The following changes since commit ccdf06c1db192152ac70a1dd974c624f566cb7d4: Open 6.1 development tree (2021-04-30 11:15:40 +0100) are available in the Git repository at: git://repo.or.cz/qemu/kevin.git tags/for-upstream for you to fetch changes up to 68bf7336533faa6aa90fdd4558edddbf5d8ef814: vhost-user-blk: Fail gracefully on too large queue size (2021-04-30 12:27:48 +0200) ---------------------------------------------------------------- Block layer patches - Fix permission update order problems with block graph changes - qemu-img convert: Unshare write permission for source - vhost-user-blk: Fail gracefully on too large queue size ---------------------------------------------------------------- Kevin Wolf (3): block: Add BDRV_O_NO_SHARE for blk_new_open() qemu-img convert: Unshare write permission for source vhost-user-blk: Fail gracefully on too large queue size Vladimir Sementsov-Ogievskiy (36): tests/test-bdrv-graph-mod: add test_parallel_exclusive_write tests/test-bdrv-graph-mod: add test_parallel_perm_update tests/test-bdrv-graph-mod: add test_append_greedy_filter block: bdrv_append(): don't consume reference block: BdrvChildClass: add .get_parent_aio_context handler block: drop ctx argument from bdrv_root_attach_child block: make bdrv_reopen_{prepare,commit,abort} private util: add transactions.c block: bdrv_refresh_perms: check for parents permissions conflict block: refactor bdrv_child* permission functions block: rewrite bdrv_child_try_set_perm() using bdrv_refresh_perms() block: inline bdrv_child_*() permission functions calls block: use topological sort for permission update block: add bdrv_drv_set_perm transaction action block: add bdrv_list_* permission update functions block: add bdrv_replace_child_safe() transaction action block: fix bdrv_replace_node_common block: add bdrv_attach_child_common() transaction action block: add bdrv_attach_child_noperm() transaction action block: split out bdrv_replace_node_noperm() block: adapt bdrv_append() for inserting filters block: add bdrv_remove_filter_or_cow transaction action block: introduce bdrv_drop_filter() block/backup-top: drop .active block: drop ignore_children for permission update functions block: make bdrv_unset_inherits_from to be a transaction action block: make bdrv_refresh_limits() to be a transaction action block: add bdrv_set_backing_noperm() transaction action block: bdrv_reopen_multiple(): move bdrv_flush to separate pre-prepare block: bdrv_reopen_multiple: refresh permissions on updated graph block: drop unused permission update functions block: inline bdrv_check_perm_common() block: inline bdrv_replace_child() block: refactor bdrv_child_set_perm_safe() transaction action block: rename bdrv_replace_child_safe() to bdrv_replace_child() block: refactor bdrv_node_check_perm() include/block/block.h | 14 +- include/block/block_int.h | 8 +- include/qemu/transactions.h | 63 ++ block.c | 1329 ++++++++++++++++++++------------- block/backup-top.c | 48 +- block/block-backend.c | 30 +- block/commit.c | 1 + block/file-posix.c | 91 +-- block/io.c | 31 +- block/mirror.c | 3 - blockdev.c | 4 - blockjob.c | 11 +- hw/block/vhost-user-blk.c | 5 + qemu-img.c | 2 +- tests/unit/test-bdrv-drain.c | 2 +- tests/unit/test-bdrv-graph-mod.c | 209 +++++- util/transactions.c | 96 +++ MAINTAINERS | 6 + tests/qemu-iotests/245 | 2 +- tests/qemu-iotests/283.out | 2 +- tests/qemu-iotests/tests/qsd-jobs.out | 2 +- util/meson.build | 1 + 22 files changed, 1280 insertions(+), 680 deletions(-) create mode 100644 include/qemu/transactions.h create mode 100644 util/transactions.c From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Add the test that shows that concept of ignore_children is incomplete. Actually, when we want to update something, ignoring permission of some existing BdrvChild, we should ignore also the propagated effect of this child to the other children. But that's not done. Better approach (update permissions on already updated graph) will be implemented later. Now the test fails, so it's added with -d argument to not break make check. Test fails with "Conflicts with use by fl1 as 'backing', which does not allow 'write' on base" because when updating permissions we can ignore original top->fl1 BdrvChild. But we don't ignore exclusive write permission in fl1->base BdrvChild, which is propagated. Correct thing to do is make graph change first and then do permission update from the top node. To run test do ./test-bdrv-graph-mod -d -p /bdrv-graph-mod/parallel-exclusive-write from <build-directory>/tests. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-2-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- tests/unit/test-bdrv-graph-mod.c | 70 +++++++++++++++++++++++++++++++- 1 file changed, 69 insertions(+), 1 deletion(-) diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-graph-mod.c +++ b/tests/unit/test-bdrv-graph-mod.c @@ -XXX,XX +XXX,XX @@ /* * Block node graph modifications tests * - * Copyright (c) 2019 Virtuozzo International GmbH. All rights reserved. + * Copyright (c) 2019-2021 Virtuozzo International GmbH. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -XXX,XX +XXX,XX @@ static BlockDriver bdrv_no_perm = { .bdrv_child_perm = no_perm_default_perms, }; +static void exclusive_write_perms(BlockDriverState *bs, BdrvChild *c, + BdrvChildRole role, + BlockReopenQueue *reopen_queue, + uint64_t perm, uint64_t shared, + uint64_t *nperm, uint64_t *nshared) +{ + *nperm = BLK_PERM_WRITE; + *nshared = BLK_PERM_ALL & ~BLK_PERM_WRITE; +} + +static BlockDriver bdrv_exclusive_writer = { + .format_name = "exclusive-writer", + .bdrv_child_perm = exclusive_write_perms, +}; + static BlockDriverState *no_perm_node(const char *name) { return bdrv_new_open_driver(&bdrv_no_perm, name, BDRV_O_RDWR, &error_abort); @@ -XXX,XX +XXX,XX @@ static BlockDriverState *pass_through_node(const char *name) BDRV_O_RDWR, &error_abort); } +static BlockDriverState *exclusive_writer_node(const char *name) +{ + return bdrv_new_open_driver(&bdrv_exclusive_writer, name, + BDRV_O_RDWR, &error_abort); +} + /* * test_update_perm_tree * @@ -XXX,XX +XXX,XX @@ static void test_should_update_child(void) blk_unref(root); } +/* + * test_parallel_exclusive_write + * + * Check that when we replace node, old permissions of the node being removed + * doesn't break the replacement. + */ +static void test_parallel_exclusive_write(void) +{ + BlockDriverState *top = exclusive_writer_node("top"); + BlockDriverState *base = no_perm_node("base"); + BlockDriverState *fl1 = pass_through_node("fl1"); + BlockDriverState *fl2 = pass_through_node("fl2"); + + /* + * bdrv_attach_child() eats child bs reference, so we need two @base + * references for two filters: + */ + bdrv_ref(base); + + bdrv_attach_child(top, fl1, "backing", &child_of_bds, BDRV_CHILD_DATA, + &error_abort); + bdrv_attach_child(fl1, base, "backing", &child_of_bds, BDRV_CHILD_FILTERED, + &error_abort); + bdrv_attach_child(fl2, base, "backing", &child_of_bds, BDRV_CHILD_FILTERED, + &error_abort); + + bdrv_replace_node(fl1, fl2, &error_abort); + + bdrv_unref(fl2); + bdrv_unref(top); +} + int main(int argc, char *argv[]) { + int i; + bool debug = false; + + for (i = 1; i < argc; i++) { + if (!strcmp(argv[i], "-d")) { + debug = true; + break; + } + } + bdrv_init(); qemu_init_main_loop(&error_abort); @@ -XXX,XX +XXX,XX @@ int main(int argc, char *argv[]) g_test_add_func("/bdrv-graph-mod/should-update-child", test_should_update_child); + if (debug) { + g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write", + test_parallel_exclusive_write); + } + return g_test_run(); } -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Add test to show that simple DFS recursion order is not correct for permission update. Correct order is topological-sort order, which will be introduced later. Consider the block driver which has two filter children: one active with exclusive write access and one inactive with no specific permissions. And, these two children has a common base child, like this: ┌─────┐ ┌──────┐ │ fl2 │ ◀── │ top │ └─────┘ └──────┘ │ │ │ │ w │ ▼ │ ┌──────┐ │ │ fl1 │ │ └──────┘ │ │ │ │ w │ ▼ │ ┌──────┐ └───────▶ │ base │ └──────┘ So, exclusive write is propagated. Assume, we want to make fl2 active instead of fl1. So, we set some option for top driver and do permission update. If permission update (remember, it's DFS) goes first through top->fl1->base branch it will succeed: it firstly drop exclusive write permissions and than apply them for another BdrvChildren. But if permission update goes first through top->fl2->base branch it will fail, as when we try to update fl2->base child, old not yet updated fl1->base child will be in conflict. Now test fails, so it runs only with -d flag. To run do ./test-bdrv-graph-mod -d -p /bdrv-graph-mod/parallel-perm-update from <build-directory>/tests. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-3-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- tests/unit/test-bdrv-graph-mod.c | 116 +++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-graph-mod.c +++ b/tests/unit/test-bdrv-graph-mod.c @@ -XXX,XX +XXX,XX @@ static void test_parallel_exclusive_write(void) bdrv_unref(top); } +static void write_to_file_perms(BlockDriverState *bs, BdrvChild *c, + BdrvChildRole role, + BlockReopenQueue *reopen_queue, + uint64_t perm, uint64_t shared, + uint64_t *nperm, uint64_t *nshared) +{ + if (bs->file && c == bs->file) { + *nperm = BLK_PERM_WRITE; + *nshared = BLK_PERM_ALL & ~BLK_PERM_WRITE; + } else { + *nperm = 0; + *nshared = BLK_PERM_ALL; + } +} + +static BlockDriver bdrv_write_to_file = { + .format_name = "tricky-perm", + .bdrv_child_perm = write_to_file_perms, +}; + + +/* + * The following test shows that topological-sort order is required for + * permission update, simple DFS is not enough. + * + * Consider the block driver which has two filter children: one active + * with exclusive write access and one inactive with no specific + * permissions. + * + * And, these two children has a common base child, like this: + * + * ┌─────┐ ┌──────┐ + * │ fl2 │ ◀── │ top │ + * └─────┘ └──────┘ + * │ │ + * │ │ w + * │ ▼ + * │ ┌──────┐ + * │ │ fl1 │ + * │ └──────┘ + * │ │ + * │ │ w + * │ ▼ + * │ ┌──────┐ + * └───────▶ │ base │ + * └──────┘ + * + * So, exclusive write is propagated. + * + * Assume, we want to make fl2 active instead of fl1. + * So, we set some option for top driver and do permission update. + * + * With simple DFS, if permission update goes first through + * top->fl1->base branch it will succeed: it firstly drop exclusive write + * permissions and than apply them for another BdrvChildren. + * But if permission update goes first through top->fl2->base branch it + * will fail, as when we try to update fl2->base child, old not yet + * updated fl1->base child will be in conflict. + * + * With topological-sort order we always update parents before children, so fl1 + * and fl2 are both updated when we update base and there is no conflict. + */ +static void test_parallel_perm_update(void) +{ + BlockDriverState *top = no_perm_node("top"); + BlockDriverState *tricky = + bdrv_new_open_driver(&bdrv_write_to_file, "tricky", BDRV_O_RDWR, + &error_abort); + BlockDriverState *base = no_perm_node("base"); + BlockDriverState *fl1 = pass_through_node("fl1"); + BlockDriverState *fl2 = pass_through_node("fl2"); + BdrvChild *c_fl1, *c_fl2; + + /* + * bdrv_attach_child() eats child bs reference, so we need two @base + * references for two filters: + */ + bdrv_ref(base); + + bdrv_attach_child(top, tricky, "file", &child_of_bds, BDRV_CHILD_DATA, + &error_abort); + c_fl1 = bdrv_attach_child(tricky, fl1, "first", &child_of_bds, + BDRV_CHILD_FILTERED, &error_abort); + c_fl2 = bdrv_attach_child(tricky, fl2, "second", &child_of_bds, + BDRV_CHILD_FILTERED, &error_abort); + bdrv_attach_child(fl1, base, "backing", &child_of_bds, BDRV_CHILD_FILTERED, + &error_abort); + bdrv_attach_child(fl2, base, "backing", &child_of_bds, BDRV_CHILD_FILTERED, + &error_abort); + + /* Select fl1 as first child to be active */ + tricky->file = c_fl1; + bdrv_child_refresh_perms(top, top->children.lh_first, &error_abort); + + assert(c_fl1->perm & BLK_PERM_WRITE); + assert(!(c_fl2->perm & BLK_PERM_WRITE)); + + /* Now, try to switch active child and update permissions */ + tricky->file = c_fl2; + bdrv_child_refresh_perms(top, top->children.lh_first, &error_abort); + + assert(c_fl2->perm & BLK_PERM_WRITE); + assert(!(c_fl1->perm & BLK_PERM_WRITE)); + + /* Switch once more, to not care about real child order in the list */ + tricky->file = c_fl1; + bdrv_child_refresh_perms(top, top->children.lh_first, &error_abort); + + assert(c_fl1->perm & BLK_PERM_WRITE); + assert(!(c_fl2->perm & BLK_PERM_WRITE)); + + bdrv_unref(top); +} + int main(int argc, char *argv[]) { int i; @@ -XXX,XX +XXX,XX @@ int main(int argc, char *argv[]) if (debug) { g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write", test_parallel_exclusive_write); + g_test_add_func("/bdrv-graph-mod/parallel-perm-update", + test_parallel_perm_update); } return g_test_run(); -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> bdrv_append() is not quite good for inserting filters: it does extra permission update in intermediate state, where filter get it filtered child but is not yet replace it in a backing chain. Some filters (for example backup-top) may want permissions even when have no parents. And described intermediate state becomes invalid. That's (half a) reason, why we need "inactive" state for backup-top filter. bdrv_append() will be improved later, now let's add a unit test. Now test fails, so it runs only with -d flag. To run do ./test-bdrv-graph-mod -d -p /bdrv-graph-mod/append-greedy-filter from <build-directory>/tests. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-4-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- tests/unit/test-bdrv-graph-mod.c | 33 ++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-graph-mod.c +++ b/tests/unit/test-bdrv-graph-mod.c @@ -XXX,XX +XXX,XX @@ static void test_parallel_perm_update(void) bdrv_unref(top); } +/* + * It's possible that filter required permissions allows to insert it to backing + * chain, like: + * + * 1. [top] -> [filter] -> [base] + * + * but doesn't allow to add it as a branch: + * + * 2. [filter] --\ + * v + * [top] -> [base] + * + * So, inserting such filter should do all graph modifications and only then + * update permissions. If we try to go through intermediate state [2] and update + * permissions on it we'll fail. + * + * Let's check that bdrv_append() can append such a filter. + */ +static void test_append_greedy_filter(void) +{ + BlockDriverState *top = exclusive_writer_node("top"); + BlockDriverState *base = no_perm_node("base"); + BlockDriverState *fl = exclusive_writer_node("fl1"); + + bdrv_attach_child(top, base, "backing", &child_of_bds, BDRV_CHILD_COW, + &error_abort); + + bdrv_append(fl, base, &error_abort); + bdrv_unref(top); +} + int main(int argc, char *argv[]) { int i; @@ -XXX,XX +XXX,XX @@ int main(int argc, char *argv[]) test_parallel_exclusive_write); g_test_add_func("/bdrv-graph-mod/parallel-perm-update", test_parallel_perm_update); + g_test_add_func("/bdrv-graph-mod/append-greedy-filter", + test_append_greedy_filter); } return g_test_run(); -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> We have too much comments for this feature. It seems better just don't do it. Most of real users (tests don't count) have to create additional reference. Drop also comment in external_snapshot_prepare: - bdrv_append doesn't "remove" old bs in common sense, it sounds strange - the fact that bdrv_append can fail is obvious from the context - the fact that we must rollback all changes in transaction abort is known (it's the direct role of abort) Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-5-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 25 +++---------------------- block/backup-top.c | 1 - block/commit.c | 1 + block/mirror.c | 3 --- blockdev.c | 4 ---- tests/unit/test-bdrv-drain.c | 2 +- tests/unit/test-bdrv-graph-mod.c | 3 +++ 7 files changed, 8 insertions(+), 31 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs, goto out; } - /* bdrv_append() consumes a strong reference to bs_snapshot - * (i.e. it will call bdrv_unref() on it) even on error, so in - * order to be able to return one, we have to increase - * bs_snapshot's refcount here */ - bdrv_ref(bs_snapshot); ret = bdrv_append(bs_snapshot, bs, errp); if (ret < 0) { bs_snapshot = NULL; @@ -XXX,XX +XXX,XX @@ int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, * bs_new must not be attached to a BlockBackend. * * This function does not create any image files. - * - * bdrv_append() takes ownership of a bs_new reference and unrefs it because - * that's what the callers commonly need. bs_new will be referenced by the old - * parents of bs_top after bdrv_append() returns. If the caller needs to keep a - * reference of its own, it must call bdrv_ref(). */ int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top, Error **errp) { int ret = bdrv_set_backing_hd(bs_new, bs_top, errp); if (ret < 0) { - goto out; + return ret; } ret = bdrv_replace_node(bs_top, bs_new, errp); if (ret < 0) { bdrv_set_backing_hd(bs_new, NULL, &error_abort); - goto out; + return ret; } - ret = 0; - -out: - /* - * bs_new is now referenced by its new parents, we don't need the - * additional reference any more. - */ - bdrv_unref(bs_new); - - return ret; + return 0; } static void bdrv_delete(BlockDriverState *bs) diff --git a/block/backup-top.c b/block/backup-top.c index XXXXXXX..XXXXXXX 100644 --- a/block/backup-top.c +++ b/block/backup-top.c @@ -XXX,XX +XXX,XX @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, bdrv_drained_begin(source); - bdrv_ref(top); ret = bdrv_append(top, source, errp); if (ret < 0) { error_prepend(errp, "Cannot append backup-top filter: "); diff --git a/block/commit.c b/block/commit.c index XXXXXXX..XXXXXXX 100644 --- a/block/commit.c +++ b/block/commit.c @@ -XXX,XX +XXX,XX @@ void commit_start(const char *job_id, BlockDriverState *bs, commit_top_bs->total_sectors = top->total_sectors; ret = bdrv_append(commit_top_bs, top, errp); + bdrv_unref(commit_top_bs); /* referenced by new parents or failed */ if (ret < 0) { commit_top_bs = NULL; goto fail; diff --git a/block/mirror.c b/block/mirror.c index XXXXXXX..XXXXXXX 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -XXX,XX +XXX,XX @@ static BlockJob *mirror_start_job( bs_opaque->is_commit = target_is_backing; - /* bdrv_append takes ownership of the mirror_top_bs reference, need to keep - * it alive until block_job_create() succeeds even if bs has no parent. */ - bdrv_ref(mirror_top_bs); bdrv_drained_begin(bs); ret = bdrv_append(mirror_top_bs, bs, errp); bdrv_drained_end(bs); diff --git a/blockdev.c b/blockdev.c index XXXXXXX..XXXXXXX 100644 --- a/blockdev.c +++ b/blockdev.c @@ -XXX,XX +XXX,XX @@ static void external_snapshot_prepare(BlkActionState *common, goto out; } - /* This removes our old bs and adds the new bs. This is an operation that - * can fail, so we need to do it in .prepare; undoing it for abort is - * always possible. */ - bdrv_ref(state->new_bs); ret = bdrv_append(state->new_bs, state->old_bs, errp); if (ret < 0) { goto out; diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-drain.c +++ b/tests/unit/test-bdrv-drain.c @@ -XXX,XX +XXX,XX @@ static void test_append_to_drained(void) g_assert_cmpint(base_s->drain_count, ==, 1); g_assert_cmpint(base->in_flight, ==, 0); - /* Takes ownership of overlay, so we don't have to unref it later */ bdrv_append(overlay, base, &error_abort); g_assert_cmpint(base->in_flight, ==, 0); g_assert_cmpint(overlay->in_flight, ==, 0); @@ -XXX,XX +XXX,XX @@ static void test_append_to_drained(void) g_assert_cmpint(overlay->quiesce_counter, ==, 0); g_assert_cmpint(overlay_s->drain_count, ==, 0); + bdrv_unref(overlay); bdrv_unref(base); blk_unref(blk); } diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-graph-mod.c +++ b/tests/unit/test-bdrv-graph-mod.c @@ -XXX,XX +XXX,XX @@ static void test_update_perm_tree(void) ret = bdrv_append(filter, bs, NULL); g_assert_cmpint(ret, <, 0); + bdrv_unref(filter); blk_unref(root); } @@ -XXX,XX +XXX,XX @@ static void test_should_update_child(void) bdrv_append(filter, bs, &error_abort); g_assert(target->backing->bs == bs); + bdrv_unref(filter); bdrv_unref(bs); blk_unref(root); } @@ -XXX,XX +XXX,XX @@ static void test_append_greedy_filter(void) &error_abort); bdrv_append(fl, base, &error_abort); + bdrv_unref(fl); bdrv_unref(top); } -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Add new handler to get aio context and implement it in all child classes. Add corresponding public interface to be used soon. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-6-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block.h | 2 ++ include/block/block_int.h | 2 ++ block.c | 13 +++++++++++++ block/block-backend.c | 9 +++++++++ blockjob.c | 8 ++++++++ 5 files changed, 34 insertions(+) diff --git a/include/block/block.h b/include/block/block.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -XXX,XX +XXX,XX @@ bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx, GSList **ignore, Error **errp); bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx, GSList **ignore, Error **errp); +AioContext *bdrv_child_get_parent_aio_context(BdrvChild *c); + int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz); int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo); diff --git a/include/block/block_int.h b/include/block/block_int.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -XXX,XX +XXX,XX @@ struct BdrvChildClass { bool (*can_set_aio_ctx)(BdrvChild *child, AioContext *ctx, GSList **ignore, Error **errp); void (*set_aio_ctx)(BdrvChild *child, AioContext *ctx, GSList **ignore); + + AioContext *(*get_parent_aio_context)(BdrvChild *child); }; extern const BdrvChildClass child_of_bds; diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_child_cb_update_filename(BdrvChild *c, BlockDriverState *base, return 0; } +static AioContext *bdrv_child_cb_get_parent_aio_context(BdrvChild *c) +{ + BlockDriverState *bs = c->opaque; + + return bdrv_get_aio_context(bs); +} + const BdrvChildClass child_of_bds = { .parent_is_bds = true, .get_parent_desc = bdrv_child_get_parent_desc, @@ -XXX,XX +XXX,XX @@ const BdrvChildClass child_of_bds = { .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx, .set_aio_ctx = bdrv_child_cb_set_aio_ctx, .update_filename = bdrv_child_cb_update_filename, + .get_parent_aio_context = bdrv_child_cb_get_parent_aio_context, }; +AioContext *bdrv_child_get_parent_aio_context(BdrvChild *c) +{ + return c->klass->get_parent_aio_context(c); +} + static int bdrv_open_flags(BlockDriverState *bs, int flags) { int open_flags = flags; diff --git a/block/block-backend.c b/block/block-backend.c index XXXXXXX..XXXXXXX 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -XXX,XX +XXX,XX @@ static void blk_root_detach(BdrvChild *child) } } +static AioContext *blk_root_get_parent_aio_context(BdrvChild *c) +{ + BlockBackend *blk = c->opaque; + + return blk_get_aio_context(blk); +} + static const BdrvChildClass child_root = { .inherit_options = blk_root_inherit_options, @@ -XXX,XX +XXX,XX @@ static const BdrvChildClass child_root = { .can_set_aio_ctx = blk_root_can_set_aio_ctx, .set_aio_ctx = blk_root_set_aio_ctx, + + .get_parent_aio_context = blk_root_get_parent_aio_context, }; /* diff --git a/blockjob.c b/blockjob.c index XXXXXXX..XXXXXXX 100644 --- a/blockjob.c +++ b/blockjob.c @@ -XXX,XX +XXX,XX @@ static void child_job_set_aio_ctx(BdrvChild *c, AioContext *ctx, job->job.aio_context = ctx; } +static AioContext *child_job_get_parent_aio_context(BdrvChild *c) +{ + BlockJob *job = c->opaque; + + return job->job.aio_context; +} + static const BdrvChildClass child_job = { .get_parent_desc = child_job_get_parent_desc, .drained_begin = child_job_drained_begin, @@ -XXX,XX +XXX,XX @@ static const BdrvChildClass child_job = { .can_set_aio_ctx = child_job_can_set_aio_ctx, .set_aio_ctx = child_job_set_aio_ctx, .stay_at_node = true, + .get_parent_aio_context = child_job_get_parent_aio_context, }; void block_job_remove_all_bdrv(BlockJob *job) -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Passing parent aio context is redundant, as child_class and parent opaque pointer are enough to retrieve it. Drop the argument and use new bdrv_child_get_parent_aio_context() interface. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-7-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block_int.h | 1 - block.c | 8 +++++--- block/block-backend.c | 4 ++-- blockjob.c | 3 +-- 4 files changed, 8 insertions(+), 8 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -XXX,XX +XXX,XX @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, const char *child_name, const BdrvChildClass *child_class, BdrvChildRole child_role, - AioContext *ctx, uint64_t perm, uint64_t shared_perm, void *opaque, Error **errp); void bdrv_root_unref_child(BdrvChild *child); diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, const char *child_name, const BdrvChildClass *child_class, BdrvChildRole child_role, - AioContext *ctx, uint64_t perm, uint64_t shared_perm, void *opaque, Error **errp) { BdrvChild *child; Error *local_err = NULL; int ret; + AioContext *ctx; ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp); if (ret < 0) { @@ -XXX,XX +XXX,XX @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, .opaque = opaque, }; + ctx = bdrv_child_get_parent_aio_context(child); + /* If the AioContexts don't match, first try to move the subtree of * child_bs into the AioContext of the new parent. If this doesn't work, * try moving the parent into the AioContext of child_bs instead. */ @@ -XXX,XX +XXX,XX @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, perm, shared_perm, &perm, &shared_perm); child = bdrv_root_attach_child(child_bs, child_name, child_class, - child_role, bdrv_get_aio_context(parent_bs), - perm, shared_perm, parent_bs, errp); + child_role, perm, shared_perm, parent_bs, + errp); if (child == NULL) { return NULL; } diff --git a/block/block-backend.c b/block/block-backend.c index XXXXXXX..XXXXXXX 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -XXX,XX +XXX,XX @@ BlockBackend *blk_new_open(const char *filename, const char *reference, blk->root = bdrv_root_attach_child(bs, "root", &child_root, BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, - blk->ctx, perm, BLK_PERM_ALL, blk, errp); + perm, BLK_PERM_ALL, blk, errp); if (!blk->root) { blk_unref(blk); return NULL; @@ -XXX,XX +XXX,XX @@ int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error **errp) bdrv_ref(bs); blk->root = bdrv_root_attach_child(bs, "root", &child_root, BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, - blk->ctx, blk->perm, blk->shared_perm, + blk->perm, blk->shared_perm, blk, errp); if (blk->root == NULL) { return -EPERM; diff --git a/blockjob.c b/blockjob.c index XXXXXXX..XXXXXXX 100644 --- a/blockjob.c +++ b/blockjob.c @@ -XXX,XX +XXX,XX @@ int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs, if (need_context_ops && job->job.aio_context != qemu_get_aio_context()) { aio_context_release(job->job.aio_context); } - c = bdrv_root_attach_child(bs, name, &child_job, 0, - job->job.aio_context, perm, shared_perm, job, + c = bdrv_root_attach_child(bs, name, &child_job, 0, perm, shared_perm, job, errp); if (need_context_ops && job->job.aio_context != qemu_get_aio_context()) { aio_context_acquire(job->job.aio_context); -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> These functions are called only from bdrv_reopen_multiple() in block.c. No reason to publish them. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-8-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block.h | 4 ---- block.c | 13 +++++++++---- 2 files changed, 9 insertions(+), 8 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -XXX,XX +XXX,XX @@ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp); int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only, Error **errp); -int bdrv_reopen_prepare(BDRVReopenState *reopen_state, - BlockReopenQueue *queue, Error **errp); -void bdrv_reopen_commit(BDRVReopenState *reopen_state); -void bdrv_reopen_abort(BDRVReopenState *reopen_state); int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset, int64_t bytes, BdrvRequestFlags flags); int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags); diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static BlockDriverState *bdrv_open_inherit(const char *filename, BdrvChildRole child_role, Error **errp); +static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue + *queue, Error **errp); +static void bdrv_reopen_commit(BDRVReopenState *reopen_state); +static void bdrv_reopen_abort(BDRVReopenState *reopen_state); + /* If non-zero, use only whitelisted block drivers */ static int use_bdrv_whitelist; @@ -XXX,XX +XXX,XX @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state, * commit() for any other BDS that have been left in a prepare() state * */ -int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, - Error **errp) +static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, + BlockReopenQueue *queue, Error **errp) { int ret = -1; int old_flags; @@ -XXX,XX +XXX,XX @@ error: * makes them final by swapping the staging BlockDriverState contents into * the active BlockDriverState contents. */ -void bdrv_reopen_commit(BDRVReopenState *reopen_state) +static void bdrv_reopen_commit(BDRVReopenState *reopen_state) { BlockDriver *drv; BlockDriverState *bs; @@ -XXX,XX +XXX,XX @@ void bdrv_reopen_commit(BDRVReopenState *reopen_state) * Abort the reopen, and delete and free the staged changes in * reopen_state */ -void bdrv_reopen_abort(BDRVReopenState *reopen_state) +static void bdrv_reopen_abort(BDRVReopenState *reopen_state) { BlockDriver *drv; -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Add simple transaction API to use in further update of block graph operations. Supposed usage is: - "prepare" is main function of the action and it should make the main effect of the action to be visible for the following actions, keeping possibility of roll-back, saving necessary things in action state, which is prepended to the action list (to do that, prepare func should call tran_add()). So, driver struct doesn't include "prepare" field, as it is supposed to be called directly. - commit/rollback is supposed to be called for the list of action states, to commit/rollback all the actions in reverse order - When possible "commit" should not make visible effect for other actions, which make possible transparent logical interaction between actions. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-9-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/qemu/transactions.h | 63 ++++++++++++++++++++++++ util/transactions.c | 96 +++++++++++++++++++++++++++++++++++++ MAINTAINERS | 6 +++ util/meson.build | 1 + 4 files changed, 166 insertions(+) create mode 100644 include/qemu/transactions.h create mode 100644 util/transactions.c diff --git a/include/qemu/transactions.h b/include/qemu/transactions.h new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/include/qemu/transactions.h @@ -XXX,XX +XXX,XX @@ +/* + * Simple transactions API + * + * Copyright (c) 2021 Virtuozzo International GmbH. + * + * Author: + * Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * + * = Generic transaction API = + * + * The intended usage is the following: you create "prepare" functions, which + * represents the actions. They will usually have Transaction* argument, and + * call tran_add() to register finalization callbacks. For finalization + * callbacks, prepare corresponding TransactionActionDrv structures. + * + * Then, when you need to make a transaction, create an empty Transaction by + * tran_create(), call your "prepare" functions on it, and finally call + * tran_abort() or tran_commit() to finalize the transaction by corresponding + * finalization actions in reverse order. + */ + +#ifndef QEMU_TRANSACTIONS_H +#define QEMU_TRANSACTIONS_H + +#include <gmodule.h> + +typedef struct TransactionActionDrv { + void (*abort)(void *opaque); + void (*commit)(void *opaque); + void (*clean)(void *opaque); +} TransactionActionDrv; + +typedef struct Transaction Transaction; + +Transaction *tran_new(void); +void tran_add(Transaction *tran, TransactionActionDrv *drv, void *opaque); +void tran_abort(Transaction *tran); +void tran_commit(Transaction *tran); + +static inline void tran_finalize(Transaction *tran, int ret) +{ + if (ret < 0) { + tran_abort(tran); + } else { + tran_commit(tran); + } +} + +#endif /* QEMU_TRANSACTIONS_H */ diff --git a/util/transactions.c b/util/transactions.c new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/util/transactions.c @@ -XXX,XX +XXX,XX @@ +/* + * Simple transactions API + * + * Copyright (c) 2021 Virtuozzo International GmbH. + * + * Author: + * Sementsov-Ogievskiy Vladimir <vsementsov@virtuozzo.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include "qemu/osdep.h" + +#include "qemu/transactions.h" +#include "qemu/queue.h" + +typedef struct TransactionAction { + TransactionActionDrv *drv; + void *opaque; + QSLIST_ENTRY(TransactionAction) entry; +} TransactionAction; + +struct Transaction { + QSLIST_HEAD(, TransactionAction) actions; +}; + +Transaction *tran_new(void) +{ + Transaction *tran = g_new(Transaction, 1); + + QSLIST_INIT(&tran->actions); + + return tran; +} + +void tran_add(Transaction *tran, TransactionActionDrv *drv, void *opaque) +{ + TransactionAction *act; + + act = g_new(TransactionAction, 1); + *act = (TransactionAction) { + .drv = drv, + .opaque = opaque + }; + + QSLIST_INSERT_HEAD(&tran->actions, act, entry); +} + +void tran_abort(Transaction *tran) +{ + TransactionAction *act, *next; + + QSLIST_FOREACH_SAFE(act, &tran->actions, entry, next) { + if (act->drv->abort) { + act->drv->abort(act->opaque); + } + + if (act->drv->clean) { + act->drv->clean(act->opaque); + } + + g_free(act); + } + + g_free(tran); +} + +void tran_commit(Transaction *tran) +{ + TransactionAction *act, *next; + + QSLIST_FOREACH_SAFE(act, &tran->actions, entry, next) { + if (act->drv->commit) { + act->drv->commit(act->opaque); + } + + if (act->drv->clean) { + act->drv->clean(act->opaque); + } + + g_free(act); + } + + g_free(tran); +} diff --git a/MAINTAINERS b/MAINTAINERS index XXXXXXX..XXXXXXX 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -XXX,XX +XXX,XX @@ M: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> S: Maintained F: scripts/simplebench/ +Transactions helper +M: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> +S: Maintained +F: include/qemu/transactions.h +F: util/transactions.c + QAPI M: Markus Armbruster <armbru@redhat.com> M: Michael Roth <michael.roth@amd.com> diff --git a/util/meson.build b/util/meson.build index XXXXXXX..XXXXXXX 100644 --- a/util/meson.build +++ b/util/meson.build @@ -XXX,XX +XXX,XX @@ util_ss.add(files('qsp.c')) util_ss.add(files('range.c')) util_ss.add(files('stats64.c')) util_ss.add(files('systemd.c')) +util_ss.add(files('transactions.c')) util_ss.add(when: 'CONFIG_POSIX', if_true: files('drm.c')) util_ss.add(files('guest-random.c')) util_ss.add(files('yank.c')) -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Add additional check that node parents do not interfere with each other. This should not hurt existing callers and allows in further patch use bdrv_refresh_perms() to update a subtree of changed BdrvChild (check that change is correct). New check will substitute bdrv_check_update_perm() in following permissions refactoring, so keep error messages the same to avoid unit test result changes. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-10-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 54 insertions(+), 9 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ bool bdrv_is_writable(BlockDriverState *bs) return bdrv_is_writable_after_reopen(bs, NULL); } +static char *bdrv_child_user_desc(BdrvChild *c) +{ + if (c->klass->get_parent_desc) { + return c->klass->get_parent_desc(c); + } + + return g_strdup("another user"); +} + +static bool bdrv_a_allow_b(BdrvChild *a, BdrvChild *b, Error **errp) +{ + g_autofree char *user = NULL; + g_autofree char *perm_names = NULL; + + if ((b->perm & a->shared_perm) == b->perm) { + return true; + } + + perm_names = bdrv_perm_names(b->perm & ~a->shared_perm); + user = bdrv_child_user_desc(a); + error_setg(errp, "Conflicts with use by %s as '%s', which does not " + "allow '%s' on %s", + user, a->name, perm_names, bdrv_get_node_name(b->bs)); + + return false; +} + +static bool bdrv_parent_perms_conflict(BlockDriverState *bs, Error **errp) +{ + BdrvChild *a, *b; + + /* + * During the loop we'll look at each pair twice. That's correct because + * bdrv_a_allow_b() is asymmetric and we should check each pair in both + * directions. + */ + QLIST_FOREACH(a, &bs->parents, next_parent) { + QLIST_FOREACH(b, &bs->parents, next_parent) { + if (a == b) { + continue; + } + + if (!bdrv_a_allow_b(a, b, errp)) { + return true; + } + } + } + + return false; +} + static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs, BdrvChild *c, BdrvChildRole role, BlockReopenQueue *reopen_queue, @@ -XXX,XX +XXX,XX @@ void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, *shared_perm = cumulative_shared_perms; } -static char *bdrv_child_user_desc(BdrvChild *c) -{ - if (c->klass->get_parent_desc) { - return c->klass->get_parent_desc(c); - } - - return g_strdup("another user"); -} - char *bdrv_perm_names(uint64_t perm) { struct perm_name { @@ -XXX,XX +XXX,XX @@ static int bdrv_refresh_perms(BlockDriverState *bs, Error **errp) int ret; uint64_t perm, shared_perm; + if (bdrv_parent_perms_conflict(bs, errp)) { + return -EPERM; + } bdrv_get_cumulative_perm(bs, &perm, &shared_perm); ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, errp); if (ret < 0) { -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Split out non-recursive parts, and refactor as block graph transaction action. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-11-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 79 ++++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 59 insertions(+), 20 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ #include "qemu/timer.h" #include "qemu/cutils.h" #include "qemu/id.h" +#include "qemu/transactions.h" #include "block/coroutines.h" #ifdef CONFIG_BSD @@ -XXX,XX +XXX,XX @@ static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs, } } +static void bdrv_child_set_perm_commit(void *opaque) +{ + BdrvChild *c = opaque; + + c->has_backup_perm = false; +} + +static void bdrv_child_set_perm_abort(void *opaque) +{ + BdrvChild *c = opaque; + /* + * We may have child->has_backup_perm unset at this point, as in case of + * _check_ stage of permission update failure we may _check_ not the whole + * subtree. Still, _abort_ is called on the whole subtree anyway. + */ + if (c->has_backup_perm) { + c->perm = c->backup_perm; + c->shared_perm = c->backup_shared_perm; + c->has_backup_perm = false; + } +} + +static TransactionActionDrv bdrv_child_set_pem_drv = { + .abort = bdrv_child_set_perm_abort, + .commit = bdrv_child_set_perm_commit, +}; + +/* + * With tran=NULL needs to be followed by direct call to either + * bdrv_child_set_perm_commit() or bdrv_child_set_perm_abort(). + * + * With non-NULL tran needs to be followed by tran_abort() or tran_commit() + * instead. + */ +static void bdrv_child_set_perm_safe(BdrvChild *c, uint64_t perm, + uint64_t shared, Transaction *tran) +{ + if (!c->has_backup_perm) { + c->has_backup_perm = true; + c->backup_perm = c->perm; + c->backup_shared_perm = c->shared_perm; + } + /* + * Note: it's OK if c->has_backup_perm was already set, as we can find the + * same c twice during check_perm procedure + */ + + c->perm = perm; + c->shared_perm = shared; + + if (tran) { + tran_add(tran, &bdrv_child_set_pem_drv, c); + } +} + /* * Check whether permissions on this node can be changed in a way that * @cumulative_perms and @cumulative_shared_perms are the new cumulative @@ -XXX,XX +XXX,XX @@ static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, return ret; } - if (!c->has_backup_perm) { - c->has_backup_perm = true; - c->backup_perm = c->perm; - c->backup_shared_perm = c->shared_perm; - } - /* - * Note: it's OK if c->has_backup_perm was already set, as we can find the - * same child twice during check_perm procedure - */ - - c->perm = perm; - c->shared_perm = shared; + bdrv_child_set_perm_safe(c, perm, shared, NULL); return 0; } static void bdrv_child_set_perm(BdrvChild *c) { - c->has_backup_perm = false; - + bdrv_child_set_perm_commit(c); bdrv_set_perm(c->bs); } static void bdrv_child_abort_perm_update(BdrvChild *c) { - if (c->has_backup_perm) { - c->perm = c->backup_perm; - c->shared_perm = c->backup_shared_perm; - c->has_backup_perm = false; - } - + bdrv_child_set_perm_abort(c); bdrv_abort_perm_update(c->bs); } -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> We are going to drop recursive bdrv_child_* functions, so stop use them in bdrv_child_try_set_perm() as a first step. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-12-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, Error **errp) { Error *local_err = NULL; + Transaction *tran = tran_new(); int ret; - ret = bdrv_child_check_perm(c, NULL, perm, shared, NULL, &local_err); + bdrv_child_set_perm_safe(c, perm, shared, tran); + + ret = bdrv_refresh_perms(c->bs, &local_err); + + tran_finalize(tran, ret); + if (ret < 0) { - bdrv_child_abort_perm_update(c); if ((perm & ~c->perm) || (c->shared_perm & ~shared)) { /* tighten permissions */ error_propagate(errp, local_err); @@ -XXX,XX +XXX,XX @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, error_free(local_err); ret = 0; } - return ret; } - bdrv_child_set_perm(c); - - return 0; + return ret; } int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp) -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Each of them has only one caller. Open-coding simplifies further pemission-update system changes. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-13-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 59 +++++++++++++++++---------------------------------------- 1 file changed, 17 insertions(+), 42 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_fill_options(QDict **options, const char *filename, return 0; } -static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, - uint64_t perm, uint64_t shared, - GSList *ignore_children, Error **errp); -static void bdrv_child_abort_perm_update(BdrvChild *c); -static void bdrv_child_set_perm(BdrvChild *c); +static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, + uint64_t new_used_perm, + uint64_t new_shared_perm, + GSList *ignore_children, + Error **errp); typedef struct BlockReopenQueueEntry { bool prepared; @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, /* Check all children */ QLIST_FOREACH(c, &bs->children, next) { uint64_t cur_perm, cur_shared; + GSList *cur_ignore_children; bdrv_child_perm(bs, c->bs, c, c->role, q, cumulative_perms, cumulative_shared_perms, &cur_perm, &cur_shared); - ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, ignore_children, - errp); + + cur_ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c); + ret = bdrv_check_update_perm(c->bs, q, cur_perm, cur_shared, + cur_ignore_children, errp); + g_slist_free(cur_ignore_children); if (ret < 0) { return ret; } + + bdrv_child_set_perm_safe(c, cur_perm, cur_shared, NULL); } return 0; @@ -XXX,XX +XXX,XX @@ static void bdrv_abort_perm_update(BlockDriverState *bs) } QLIST_FOREACH(c, &bs->children, next) { - bdrv_child_abort_perm_update(c); + bdrv_child_set_perm_abort(c); + bdrv_abort_perm_update(c->bs); } } @@ -XXX,XX +XXX,XX @@ static void bdrv_set_perm(BlockDriverState *bs) /* Update all children */ QLIST_FOREACH(c, &bs->children, next) { - bdrv_child_set_perm(c); + bdrv_child_set_perm_commit(c); + bdrv_set_perm(c->bs); } } @@ -XXX,XX +XXX,XX @@ static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, ignore_children, errp); } -/* Needs to be followed by a call to either bdrv_child_set_perm() or - * bdrv_child_abort_perm_update(). */ -static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, - uint64_t perm, uint64_t shared, - GSList *ignore_children, Error **errp) -{ - int ret; - - ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c); - ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children, errp); - g_slist_free(ignore_children); - - if (ret < 0) { - return ret; - } - - bdrv_child_set_perm_safe(c, perm, shared, NULL); - - return 0; -} - -static void bdrv_child_set_perm(BdrvChild *c) -{ - bdrv_child_set_perm_commit(c); - bdrv_set_perm(c->bs); -} - -static void bdrv_child_abort_perm_update(BdrvChild *c) -{ - bdrv_child_set_perm_abort(c); - bdrv_abort_perm_update(c->bs); -} - static int bdrv_refresh_perms(BlockDriverState *bs, Error **errp) { int ret; -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Rewrite bdrv_check_perm(), bdrv_abort_perm_update() and bdrv_set_perm() to update nodes in topological sort order instead of simple DFS. With topologically sorted nodes, we update a node only when all its parents already updated. With DFS it's not so. Consider the following example: A -+ | | | v | B | | v | C<-+ A is parent for B and C, B is parent for C. Obviously, to update permissions, we should go in order A B C, so, when we update C, all parent permissions already updated. But with current approach (simple recursion) we can update in sequence A C B C (C is updated twice). On first update of C, we consider old B permissions, so doing wrong thing. If it succeed, all is OK, on second C update we will finish with correct graph. But if the wrong thing failed, we break the whole process for no reason (it's possible that updated B permission will be less strict, but we will never check it). Also new approach gives a way to simultaneously and correctly update several nodes, we just need to run bdrv_topological_dfs() several times to add all nodes and their subtrees into one topologically sorted list (next patch will update bdrv_replace_node() in this manner). Test test_parallel_perm_update() is now passing, so move it out of debugging "if". We also need to support ignore_children in bdrv_parent_perms_conflict() For test 283 order of conflicting parents check is changed. Note also that in bdrv_check_perm() we don't check for parents conflict at root bs, as we may be in the middle of permission update in bdrv_reopen_multiple(). bdrv_reopen_multiple() will be updated soon. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-14-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 116 +++++++++++++++++++++++++------ tests/unit/test-bdrv-graph-mod.c | 4 +- tests/qemu-iotests/283.out | 2 +- 3 files changed, 99 insertions(+), 23 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static bool bdrv_a_allow_b(BdrvChild *a, BdrvChild *b, Error **errp) return false; } -static bool bdrv_parent_perms_conflict(BlockDriverState *bs, Error **errp) +static bool bdrv_parent_perms_conflict(BlockDriverState *bs, + GSList *ignore_children, + Error **errp) { BdrvChild *a, *b; @@ -XXX,XX +XXX,XX @@ static bool bdrv_parent_perms_conflict(BlockDriverState *bs, Error **errp) * directions. */ QLIST_FOREACH(a, &bs->parents, next_parent) { + if (g_slist_find(ignore_children, a)) { + continue; + } + QLIST_FOREACH(b, &bs->parents, next_parent) { - if (a == b) { + if (a == b || g_slist_find(ignore_children, b)) { continue; } @@ -XXX,XX +XXX,XX @@ static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs, } } +/* + * Adds the whole subtree of @bs (including @bs itself) to the @list (except for + * nodes that are already in the @list, of course) so that final list is + * topologically sorted. Return the result (GSList @list object is updated, so + * don't use old reference after function call). + * + * On function start @list must be already topologically sorted and for any node + * in the @list the whole subtree of the node must be in the @list as well. The + * simplest way to satisfy this criteria: use only result of + * bdrv_topological_dfs() or NULL as @list parameter. + */ +static GSList *bdrv_topological_dfs(GSList *list, GHashTable *found, + BlockDriverState *bs) +{ + BdrvChild *child; + g_autoptr(GHashTable) local_found = NULL; + + if (!found) { + assert(!list); + found = local_found = g_hash_table_new(NULL, NULL); + } + + if (g_hash_table_contains(found, bs)) { + return list; + } + g_hash_table_add(found, bs); + + QLIST_FOREACH(child, &bs->children, next) { + list = bdrv_topological_dfs(list, found, child->bs); + } + + return g_slist_prepend(list, bs); +} + static void bdrv_child_set_perm_commit(void *opaque) { BdrvChild *c = opaque; @@ -XXX,XX +XXX,XX @@ static void bdrv_child_set_perm_safe(BdrvChild *c, uint64_t perm, * A call to this function must always be followed by a call to bdrv_set_perm() * or bdrv_abort_perm_update(). */ -static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, - uint64_t cumulative_perms, - uint64_t cumulative_shared_perms, - GSList *ignore_children, Error **errp) +static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q, + uint64_t cumulative_perms, + uint64_t cumulative_shared_perms, + GSList *ignore_children, Error **errp) { BlockDriver *drv = bs->drv; BdrvChild *c; @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, /* Check all children */ QLIST_FOREACH(c, &bs->children, next) { uint64_t cur_perm, cur_shared; - GSList *cur_ignore_children; bdrv_child_perm(bs, c->bs, c, c->role, q, cumulative_perms, cumulative_shared_perms, &cur_perm, &cur_shared); + bdrv_child_set_perm_safe(c, cur_perm, cur_shared, NULL); + } + + return 0; +} + +static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, + uint64_t cumulative_perms, + uint64_t cumulative_shared_perms, + GSList *ignore_children, Error **errp) +{ + int ret; + BlockDriverState *root = bs; + g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, root); - cur_ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c); - ret = bdrv_check_update_perm(c->bs, q, cur_perm, cur_shared, - cur_ignore_children, errp); - g_slist_free(cur_ignore_children); + for ( ; list; list = list->next) { + bs = list->data; + + if (bs != root) { + if (bdrv_parent_perms_conflict(bs, ignore_children, errp)) { + return -EINVAL; + } + + bdrv_get_cumulative_perm(bs, &cumulative_perms, + &cumulative_shared_perms); + } + + ret = bdrv_node_check_perm(bs, q, cumulative_perms, + cumulative_shared_perms, + ignore_children, errp); if (ret < 0) { return ret; } - - bdrv_child_set_perm_safe(c, cur_perm, cur_shared, NULL); } return 0; @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, * Notifies drivers that after a previous bdrv_check_perm() call, the * permission update is not performed and any preparations made for it (e.g. * taken file locks) need to be undone. - * - * This function recursively notifies all child nodes. */ -static void bdrv_abort_perm_update(BlockDriverState *bs) +static void bdrv_node_abort_perm_update(BlockDriverState *bs) { BlockDriver *drv = bs->drv; BdrvChild *c; @@ -XXX,XX +XXX,XX @@ static void bdrv_abort_perm_update(BlockDriverState *bs) QLIST_FOREACH(c, &bs->children, next) { bdrv_child_set_perm_abort(c); - bdrv_abort_perm_update(c->bs); } } -static void bdrv_set_perm(BlockDriverState *bs) +static void bdrv_abort_perm_update(BlockDriverState *bs) +{ + g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); + + for ( ; list; list = list->next) { + bdrv_node_abort_perm_update((BlockDriverState *)list->data); + } +} + +static void bdrv_node_set_perm(BlockDriverState *bs) { uint64_t cumulative_perms, cumulative_shared_perms; BlockDriver *drv = bs->drv; @@ -XXX,XX +XXX,XX @@ static void bdrv_set_perm(BlockDriverState *bs) /* Update all children */ QLIST_FOREACH(c, &bs->children, next) { bdrv_child_set_perm_commit(c); - bdrv_set_perm(c->bs); + } +} + +static void bdrv_set_perm(BlockDriverState *bs) +{ + g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); + + for ( ; list; list = list->next) { + bdrv_node_set_perm((BlockDriverState *)list->data); } } @@ -XXX,XX +XXX,XX @@ static int bdrv_refresh_perms(BlockDriverState *bs, Error **errp) int ret; uint64_t perm, shared_perm; - if (bdrv_parent_perms_conflict(bs, errp)) { + if (bdrv_parent_perms_conflict(bs, NULL, errp)) { return -EPERM; } bdrv_get_cumulative_perm(bs, &perm, &shared_perm); diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-graph-mod.c +++ b/tests/unit/test-bdrv-graph-mod.c @@ -XXX,XX +XXX,XX @@ int main(int argc, char *argv[]) g_test_add_func("/bdrv-graph-mod/update-perm-tree", test_update_perm_tree); g_test_add_func("/bdrv-graph-mod/should-update-child", test_should_update_child); + g_test_add_func("/bdrv-graph-mod/parallel-perm-update", + test_parallel_perm_update); if (debug) { g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write", test_parallel_exclusive_write); - g_test_add_func("/bdrv-graph-mod/parallel-perm-update", - test_parallel_perm_update); g_test_add_func("/bdrv-graph-mod/append-greedy-filter", test_append_greedy_filter); } diff --git a/tests/qemu-iotests/283.out b/tests/qemu-iotests/283.out index XXXXXXX..XXXXXXX 100644 --- a/tests/qemu-iotests/283.out +++ b/tests/qemu-iotests/283.out @@ -XXX,XX +XXX,XX @@ {"execute": "blockdev-add", "arguments": {"driver": "blkdebug", "image": "base", "node-name": "other", "take-child-perms": ["write"]}} {"return": {}} {"execute": "blockdev-backup", "arguments": {"device": "source", "sync": "full", "target": "target"}} -{"error": {"class": "GenericError", "desc": "Cannot set permissions for backup-top filter: Conflicts with use by other as 'image', which uses 'write' on base"}} +{"error": {"class": "GenericError", "desc": "Cannot set permissions for backup-top filter: Conflicts with use by source as 'image', which does not allow 'write' on base"}} === backup-top should be gone after job-finalize === -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Refactor calling driver callbacks to a separate transaction action to be used later. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-15-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 70 ++++++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 54 insertions(+), 16 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static void bdrv_child_set_perm_safe(BdrvChild *c, uint64_t perm, } } +static void bdrv_drv_set_perm_commit(void *opaque) +{ + BlockDriverState *bs = opaque; + uint64_t cumulative_perms, cumulative_shared_perms; + + if (bs->drv->bdrv_set_perm) { + bdrv_get_cumulative_perm(bs, &cumulative_perms, + &cumulative_shared_perms); + bs->drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms); + } +} + +static void bdrv_drv_set_perm_abort(void *opaque) +{ + BlockDriverState *bs = opaque; + + if (bs->drv->bdrv_abort_perm_update) { + bs->drv->bdrv_abort_perm_update(bs); + } +} + +TransactionActionDrv bdrv_drv_set_perm_drv = { + .abort = bdrv_drv_set_perm_abort, + .commit = bdrv_drv_set_perm_commit, +}; + +static int bdrv_drv_set_perm(BlockDriverState *bs, uint64_t perm, + uint64_t shared_perm, Transaction *tran, + Error **errp) +{ + if (!bs->drv) { + return 0; + } + + if (bs->drv->bdrv_check_perm) { + int ret = bs->drv->bdrv_check_perm(bs, perm, shared_perm, errp); + if (ret < 0) { + return ret; + } + } + + if (tran) { + tran_add(tran, &bdrv_drv_set_perm_drv, bs); + } + + return 0; +} + /* * Check whether permissions on this node can be changed in a way that * @cumulative_perms and @cumulative_shared_perms are the new cumulative @@ -XXX,XX +XXX,XX @@ static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q, return 0; } - if (drv->bdrv_check_perm) { - ret = drv->bdrv_check_perm(bs, cumulative_perms, - cumulative_shared_perms, errp); - if (ret < 0) { - return ret; - } + ret = bdrv_drv_set_perm(bs, cumulative_perms, cumulative_shared_perms, NULL, + errp); + if (ret < 0) { + return ret; } /* Drivers that never have children can omit .bdrv_child_perm() */ @@ -XXX,XX +XXX,XX @@ static void bdrv_node_abort_perm_update(BlockDriverState *bs) return; } - if (drv->bdrv_abort_perm_update) { - drv->bdrv_abort_perm_update(bs); - } + bdrv_drv_set_perm_abort(bs); QLIST_FOREACH(c, &bs->children, next) { bdrv_child_set_perm_abort(c); @@ -XXX,XX +XXX,XX @@ static void bdrv_abort_perm_update(BlockDriverState *bs) static void bdrv_node_set_perm(BlockDriverState *bs) { - uint64_t cumulative_perms, cumulative_shared_perms; BlockDriver *drv = bs->drv; BdrvChild *c; @@ -XXX,XX +XXX,XX @@ static void bdrv_node_set_perm(BlockDriverState *bs) return; } - bdrv_get_cumulative_perm(bs, &cumulative_perms, &cumulative_shared_perms); - - /* Update this node */ - if (drv->bdrv_set_perm) { - drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms); - } + bdrv_drv_set_perm_commit(bs); /* Drivers that never have children can omit .bdrv_child_perm() */ if (!drv->bdrv_child_perm) { -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Add new interface, allowing use of existing node list. It will be used to fix bdrv_replace_node() in the further commit. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-16-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 106 +++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 71 insertions(+), 35 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_drv_set_perm(BlockDriverState *bs, uint64_t perm, static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q, uint64_t cumulative_perms, uint64_t cumulative_shared_perms, - GSList *ignore_children, Error **errp) + GSList *ignore_children, + Transaction *tran, Error **errp) { BlockDriver *drv = bs->drv; BdrvChild *c; @@ -XXX,XX +XXX,XX @@ static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q, return 0; } - ret = bdrv_drv_set_perm(bs, cumulative_perms, cumulative_shared_perms, NULL, + ret = bdrv_drv_set_perm(bs, cumulative_perms, cumulative_shared_perms, tran, errp); if (ret < 0) { return ret; @@ -XXX,XX +XXX,XX @@ static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q, bdrv_child_perm(bs, c->bs, c, c->role, q, cumulative_perms, cumulative_shared_perms, &cur_perm, &cur_shared); - bdrv_child_set_perm_safe(c, cur_perm, cur_shared, NULL); + bdrv_child_set_perm_safe(c, cur_perm, cur_shared, tran); } return 0; } -static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, - uint64_t cumulative_perms, - uint64_t cumulative_shared_perms, - GSList *ignore_children, Error **errp) +/* + * If use_cumulative_perms is true, use cumulative_perms and + * cumulative_shared_perms for first element of the list. Otherwise just refresh + * all permissions. + */ +static int bdrv_check_perm_common(GSList *list, BlockReopenQueue *q, + bool use_cumulative_perms, + uint64_t cumulative_perms, + uint64_t cumulative_shared_perms, + GSList *ignore_children, + Transaction *tran, Error **errp) { int ret; - BlockDriverState *root = bs; - g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, root); + BlockDriverState *bs; - for ( ; list; list = list->next) { + if (use_cumulative_perms) { bs = list->data; - if (bs != root) { - if (bdrv_parent_perms_conflict(bs, ignore_children, errp)) { - return -EINVAL; - } + ret = bdrv_node_check_perm(bs, q, cumulative_perms, + cumulative_shared_perms, + ignore_children, tran, errp); + if (ret < 0) { + return ret; + } - bdrv_get_cumulative_perm(bs, &cumulative_perms, - &cumulative_shared_perms); + list = list->next; + } + + for ( ; list; list = list->next) { + bs = list->data; + + if (bdrv_parent_perms_conflict(bs, ignore_children, errp)) { + return -EINVAL; } + bdrv_get_cumulative_perm(bs, &cumulative_perms, + &cumulative_shared_perms); + ret = bdrv_node_check_perm(bs, q, cumulative_perms, cumulative_shared_perms, - ignore_children, errp); + ignore_children, tran, errp); if (ret < 0) { return ret; } @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, return 0; } +static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, + uint64_t cumulative_perms, + uint64_t cumulative_shared_perms, + GSList *ignore_children, Error **errp) +{ + g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); + return bdrv_check_perm_common(list, q, true, cumulative_perms, + cumulative_shared_perms, ignore_children, + NULL, errp); +} + +static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, + Transaction *tran, Error **errp) +{ + return bdrv_check_perm_common(list, q, false, 0, 0, NULL, tran, errp); +} + /* * Notifies drivers that after a previous bdrv_check_perm() call, the * permission update is not performed and any preparations made for it (e.g. @@ -XXX,XX +XXX,XX @@ static void bdrv_node_abort_perm_update(BlockDriverState *bs) } } -static void bdrv_abort_perm_update(BlockDriverState *bs) +static void bdrv_list_abort_perm_update(GSList *list) { - g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); - for ( ; list; list = list->next) { bdrv_node_abort_perm_update((BlockDriverState *)list->data); } } +static void bdrv_abort_perm_update(BlockDriverState *bs) +{ + g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); + return bdrv_list_abort_perm_update(list); +} + static void bdrv_node_set_perm(BlockDriverState *bs) { BlockDriver *drv = bs->drv; @@ -XXX,XX +XXX,XX @@ static void bdrv_node_set_perm(BlockDriverState *bs) } } -static void bdrv_set_perm(BlockDriverState *bs) +static void bdrv_list_set_perm(GSList *list) { - g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); - for ( ; list; list = list->next) { bdrv_node_set_perm((BlockDriverState *)list->data); } } +static void bdrv_set_perm(BlockDriverState *bs) +{ + g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); + return bdrv_list_set_perm(list); +} + void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, uint64_t *shared_perm) { @@ -XXX,XX +XXX,XX @@ static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, static int bdrv_refresh_perms(BlockDriverState *bs, Error **errp) { int ret; - uint64_t perm, shared_perm; + Transaction *tran = tran_new(); + g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); - if (bdrv_parent_perms_conflict(bs, NULL, errp)) { - return -EPERM; - } - bdrv_get_cumulative_perm(bs, &perm, &shared_perm); - ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, errp); - if (ret < 0) { - bdrv_abort_perm_update(bs); - return ret; - } - bdrv_set_perm(bs); + ret = bdrv_list_refresh_perms(list, NULL, tran, errp); + tran_finalize(tran, ret); - return 0; + return ret; } int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> To be used in the following commit. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-17-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static BlockDriverState *bdrv_open_inherit(const char *filename, BdrvChildRole child_role, Error **errp); +static void bdrv_replace_child_noperm(BdrvChild *child, + BlockDriverState *new_bs); + static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, Error **errp); static void bdrv_reopen_commit(BDRVReopenState *reopen_state); @@ -XXX,XX +XXX,XX @@ static int bdrv_drv_set_perm(BlockDriverState *bs, uint64_t perm, return 0; } +typedef struct BdrvReplaceChildState { + BdrvChild *child; + BlockDriverState *old_bs; +} BdrvReplaceChildState; + +static void bdrv_replace_child_commit(void *opaque) +{ + BdrvReplaceChildState *s = opaque; + + bdrv_unref(s->old_bs); +} + +static void bdrv_replace_child_abort(void *opaque) +{ + BdrvReplaceChildState *s = opaque; + BlockDriverState *new_bs = s->child->bs; + + /* old_bs reference is transparently moved from @s to @s->child */ + bdrv_replace_child_noperm(s->child, s->old_bs); + bdrv_unref(new_bs); +} + +static TransactionActionDrv bdrv_replace_child_drv = { + .commit = bdrv_replace_child_commit, + .abort = bdrv_replace_child_abort, + .clean = g_free, +}; + +/* + * bdrv_replace_child_safe + * + * Note: real unref of old_bs is done only on commit. + */ +__attribute__((unused)) +static void bdrv_replace_child_safe(BdrvChild *child, BlockDriverState *new_bs, + Transaction *tran) +{ + BdrvReplaceChildState *s = g_new(BdrvReplaceChildState, 1); + *s = (BdrvReplaceChildState) { + .child = child, + .old_bs = child->bs, + }; + tran_add(tran, &bdrv_replace_child_drv, s); + + if (new_bs) { + bdrv_ref(new_bs); + } + bdrv_replace_child_noperm(child, new_bs); + /* old_bs reference is transparently moved from @child to @s */ +} + /* * Check whether permissions on this node can be changed in a way that * @cumulative_perms and @cumulative_shared_perms are the new cumulative -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> inore_children thing doesn't help to track all propagated permissions of children we want to ignore. The simplest way to correctly update permissions is update graph first and then do permission update. In this case we just referesh permissions for the whole subgraph (in topological-sort defined order) and everything is correctly calculated automatically without any ignore_children. So, refactor bdrv_replace_node_common to first do graph update and then refresh the permissions. Test test_parallel_exclusive_write() now pass, so move it out of debugging "if". Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-18-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 43 +++++++++++++------------------- tests/unit/test-bdrv-graph-mod.c | 4 +-- 2 files changed, 20 insertions(+), 27 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static TransactionActionDrv bdrv_replace_child_drv = { * * Note: real unref of old_bs is done only on commit. */ -__attribute__((unused)) static void bdrv_replace_child_safe(BdrvChild *child, BlockDriverState *new_bs, Transaction *tran) { @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_common(BlockDriverState *from, bool auto_skip, Error **errp) { BdrvChild *c, *next; - GSList *list = NULL, *p; - uint64_t perm = 0, shared = BLK_PERM_ALL; + Transaction *tran = tran_new(); + g_autoptr(GHashTable) found = NULL; + g_autoptr(GSList) refresh_list = NULL; int ret; /* Make sure that @from doesn't go away until we have successfully attached @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_common(BlockDriverState *from, assert(bdrv_get_aio_context(from) == bdrv_get_aio_context(to)); bdrv_drained_begin(from); - /* Put all parents into @list and calculate their cumulative permissions */ + /* + * Do the replacement without permission update. + * Replacement may influence the permissions, we should calculate new + * permissions based on new graph. If we fail, we'll roll-back the + * replacement. + */ QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) { assert(c->bs == from); if (!should_update_child(c, to)) { @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_common(BlockDriverState *from, c->name, from->node_name); goto out; } - list = g_slist_prepend(list, c); - perm |= c->perm; - shared &= c->shared_perm; + bdrv_replace_child_safe(c, to, tran); } - /* Check whether the required permissions can be granted on @to, ignoring - * all BdrvChild in @list so that they can't block themselves. */ - ret = bdrv_check_update_perm(to, NULL, perm, shared, list, errp); - if (ret < 0) { - bdrv_abort_perm_update(to); - goto out; - } + found = g_hash_table_new(NULL, NULL); - /* Now actually perform the change. We performed the permission check for - * all elements of @list at once, so set the permissions all at once at the - * very end. */ - for (p = list; p != NULL; p = p->next) { - c = p->data; + refresh_list = bdrv_topological_dfs(refresh_list, found, to); + refresh_list = bdrv_topological_dfs(refresh_list, found, from); - bdrv_ref(to); - bdrv_replace_child_noperm(c, to); - bdrv_unref(from); + ret = bdrv_list_refresh_perms(refresh_list, NULL, tran, errp); + if (ret < 0) { + goto out; } - bdrv_set_perm(to); - ret = 0; out: - g_slist_free(list); + tran_finalize(tran, ret); + bdrv_drained_end(from); bdrv_unref(from); diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-graph-mod.c +++ b/tests/unit/test-bdrv-graph-mod.c @@ -XXX,XX +XXX,XX @@ int main(int argc, char *argv[]) test_should_update_child); g_test_add_func("/bdrv-graph-mod/parallel-perm-update", test_parallel_perm_update); + g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write", + test_parallel_exclusive_write); if (debug) { - g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write", - test_parallel_exclusive_write); g_test_add_func("/bdrv-graph-mod/append-greedy-filter", test_append_greedy_filter); } -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Split out no-perm part of bdrv_root_attach_child() into separate transaction action. bdrv_root_attach_child() now moves to new permission update paradigm: first update graph relations then update permissions. qsd-jobs test output updated. Seems now permission update goes in another order. Still, the test comment say that we only want to check that command doesn't crash, and it's still so. Error message is a bit misleading as it looks like job was added first. But actually in new paradigm of graph update we can't distinguish such things. We should update the error message, but let's not do it now. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210428151804.439460-19-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 190 ++++++++++++++++++-------- tests/qemu-iotests/tests/qsd-jobs.out | 2 +- 2 files changed, 137 insertions(+), 55 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) } } -/* - * This function steals the reference to child_bs from the caller. - * That reference is later dropped by bdrv_root_unref_child(). - * - * On failure NULL is returned, errp is set and the reference to - * child_bs is also dropped. - * - * The caller must hold the AioContext lock @child_bs, but not that of @ctx - * (unless @child_bs is already in @ctx). - */ -BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, - const char *child_name, - const BdrvChildClass *child_class, - BdrvChildRole child_role, - uint64_t perm, uint64_t shared_perm, - void *opaque, Error **errp) +static void bdrv_remove_empty_child(BdrvChild *child) { - BdrvChild *child; - Error *local_err = NULL; - int ret; - AioContext *ctx; + assert(!child->bs); + QLIST_SAFE_REMOVE(child, next); + g_free(child->name); + g_free(child); +} - ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp); - if (ret < 0) { - bdrv_abort_perm_update(child_bs); - bdrv_unref(child_bs); - return NULL; +typedef struct BdrvAttachChildCommonState { + BdrvChild **child; + AioContext *old_parent_ctx; + AioContext *old_child_ctx; +} BdrvAttachChildCommonState; + +static void bdrv_attach_child_common_abort(void *opaque) +{ + BdrvAttachChildCommonState *s = opaque; + BdrvChild *child = *s->child; + BlockDriverState *bs = child->bs; + + bdrv_replace_child_noperm(child, NULL); + + if (bdrv_get_aio_context(bs) != s->old_child_ctx) { + bdrv_try_set_aio_context(bs, s->old_child_ctx, &error_abort); } - child = g_new(BdrvChild, 1); - *child = (BdrvChild) { + if (bdrv_child_get_parent_aio_context(child) != s->old_parent_ctx) { + GSList *ignore = g_slist_prepend(NULL, child); + + child->klass->can_set_aio_ctx(child, s->old_parent_ctx, &ignore, + &error_abort); + g_slist_free(ignore); + ignore = g_slist_prepend(NULL, child); + child->klass->set_aio_ctx(child, s->old_parent_ctx, &ignore); + + g_slist_free(ignore); + } + + bdrv_unref(bs); + bdrv_remove_empty_child(child); + *s->child = NULL; +} + +static TransactionActionDrv bdrv_attach_child_common_drv = { + .abort = bdrv_attach_child_common_abort, + .clean = g_free, +}; + +/* + * Common part of attaching bdrv child to bs or to blk or to job + */ +static int bdrv_attach_child_common(BlockDriverState *child_bs, + const char *child_name, + const BdrvChildClass *child_class, + BdrvChildRole child_role, + uint64_t perm, uint64_t shared_perm, + void *opaque, BdrvChild **child, + Transaction *tran, Error **errp) +{ + BdrvChild *new_child; + AioContext *parent_ctx; + AioContext *child_ctx = bdrv_get_aio_context(child_bs); + + assert(child); + assert(*child == NULL); + + new_child = g_new(BdrvChild, 1); + *new_child = (BdrvChild) { .bs = NULL, .name = g_strdup(child_name), .klass = child_class, @@ -XXX,XX +XXX,XX @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, .opaque = opaque, }; - ctx = bdrv_child_get_parent_aio_context(child); - - /* If the AioContexts don't match, first try to move the subtree of + /* + * If the AioContexts don't match, first try to move the subtree of * child_bs into the AioContext of the new parent. If this doesn't work, - * try moving the parent into the AioContext of child_bs instead. */ - if (bdrv_get_aio_context(child_bs) != ctx) { - ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err); + * try moving the parent into the AioContext of child_bs instead. + */ + parent_ctx = bdrv_child_get_parent_aio_context(new_child); + if (child_ctx != parent_ctx) { + Error *local_err = NULL; + int ret = bdrv_try_set_aio_context(child_bs, parent_ctx, &local_err); + if (ret < 0 && child_class->can_set_aio_ctx) { - GSList *ignore = g_slist_prepend(NULL, child); - ctx = bdrv_get_aio_context(child_bs); - if (child_class->can_set_aio_ctx(child, ctx, &ignore, NULL)) { + GSList *ignore = g_slist_prepend(NULL, new_child); + if (child_class->can_set_aio_ctx(new_child, child_ctx, &ignore, + NULL)) + { error_free(local_err); ret = 0; g_slist_free(ignore); - ignore = g_slist_prepend(NULL, child); - child_class->set_aio_ctx(child, ctx, &ignore); + ignore = g_slist_prepend(NULL, new_child); + child_class->set_aio_ctx(new_child, child_ctx, &ignore); } g_slist_free(ignore); } + if (ret < 0) { error_propagate(errp, local_err); - g_free(child); - bdrv_abort_perm_update(child_bs); - bdrv_unref(child_bs); - return NULL; + bdrv_remove_empty_child(new_child); + return ret; } } - /* This performs the matching bdrv_set_perm() for the above check. */ - bdrv_replace_child(child, child_bs); + bdrv_ref(child_bs); + bdrv_replace_child_noperm(new_child, child_bs); + *child = new_child; + + BdrvAttachChildCommonState *s = g_new(BdrvAttachChildCommonState, 1); + *s = (BdrvAttachChildCommonState) { + .child = child, + .old_parent_ctx = parent_ctx, + .old_child_ctx = child_ctx, + }; + tran_add(tran, &bdrv_attach_child_common_drv, s); + + return 0; +} + +static void bdrv_detach_child(BdrvChild *child) +{ + bdrv_replace_child(child, NULL); + bdrv_remove_empty_child(child); +} + +/* + * This function steals the reference to child_bs from the caller. + * That reference is later dropped by bdrv_root_unref_child(). + * + * On failure NULL is returned, errp is set and the reference to + * child_bs is also dropped. + * + * The caller must hold the AioContext lock @child_bs, but not that of @ctx + * (unless @child_bs is already in @ctx). + */ +BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, + const char *child_name, + const BdrvChildClass *child_class, + BdrvChildRole child_role, + uint64_t perm, uint64_t shared_perm, + void *opaque, Error **errp) +{ + int ret; + BdrvChild *child = NULL; + Transaction *tran = tran_new(); + + ret = bdrv_attach_child_common(child_bs, child_name, child_class, + child_role, perm, shared_perm, opaque, + &child, tran, errp); + if (ret < 0) { + bdrv_unref(child_bs); + return NULL; + } + + ret = bdrv_refresh_perms(child_bs, errp); + tran_finalize(tran, ret); + + bdrv_unref(child_bs); return child; } @@ -XXX,XX +XXX,XX @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, return child; } -static void bdrv_detach_child(BdrvChild *child) -{ - QLIST_SAFE_REMOVE(child, next); - - bdrv_replace_child(child, NULL); - - g_free(child->name); - g_free(child); -} - /* Callers must ensure that child->frozen is false. */ void bdrv_root_unref_child(BdrvChild *child) { diff --git a/tests/qemu-iotests/tests/qsd-jobs.out b/tests/qemu-iotests/tests/qsd-jobs.out index XXXXXXX..XXXXXXX 100644 --- a/tests/qemu-iotests/tests/qsd-jobs.out +++ b/tests/qemu-iotests/tests/qsd-jobs.out @@ -XXX,XX +XXX,XX @@ QMP_VERSION {"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "created", "id": "job0"}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "null", "id": "job0"}} -{"error": {"class": "GenericError", "desc": "Conflicts with use by a block device as 'root', which uses 'write' on fmt_base"}} +{"error": {"class": "GenericError", "desc": "Conflicts with use by stream job 'job0' as 'intermediate node', which does not allow 'write' on fmt_base"}} {"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_EXPORT_DELETED", "data": {"id": "export1"}} *** done -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Split no-perm part of bdrv_attach_child as separate transaction action. It will be used in later commits. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-20-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 58 insertions(+), 13 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static BlockDriverState *bdrv_open_inherit(const char *filename, static void bdrv_replace_child_noperm(BdrvChild *child, BlockDriverState *new_bs); +static int bdrv_attach_child_noperm(BlockDriverState *parent_bs, + BlockDriverState *child_bs, + const char *child_name, + const BdrvChildClass *child_class, + BdrvChildRole child_role, + BdrvChild **child, + Transaction *tran, + Error **errp); static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, Error **errp); @@ -XXX,XX +XXX,XX @@ static int bdrv_attach_child_common(BlockDriverState *child_bs, return 0; } +static int bdrv_attach_child_noperm(BlockDriverState *parent_bs, + BlockDriverState *child_bs, + const char *child_name, + const BdrvChildClass *child_class, + BdrvChildRole child_role, + BdrvChild **child, + Transaction *tran, + Error **errp) +{ + int ret; + uint64_t perm, shared_perm; + + assert(parent_bs->drv); + + bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm); + bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL, + perm, shared_perm, &perm, &shared_perm); + + ret = bdrv_attach_child_common(child_bs, child_name, child_class, + child_role, perm, shared_perm, parent_bs, + child, tran, errp); + if (ret < 0) { + return ret; + } + + QLIST_INSERT_HEAD(&parent_bs->children, *child, next); + /* + * child is removed in bdrv_attach_child_common_abort(), so don't care to + * abort this change separately. + */ + + return 0; +} + static void bdrv_detach_child(BdrvChild *child) { bdrv_replace_child(child, NULL); @@ -XXX,XX +XXX,XX @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, BdrvChildRole child_role, Error **errp) { - BdrvChild *child; - uint64_t perm, shared_perm; - - bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm); + int ret; + BdrvChild *child = NULL; + Transaction *tran = tran_new(); - assert(parent_bs->drv); - bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL, - perm, shared_perm, &perm, &shared_perm); + ret = bdrv_attach_child_noperm(parent_bs, child_bs, child_name, child_class, + child_role, &child, tran, errp); + if (ret < 0) { + goto out; + } - child = bdrv_root_attach_child(child_bs, child_name, child_class, - child_role, perm, shared_perm, parent_bs, - errp); - if (child == NULL) { - return NULL; + ret = bdrv_refresh_perms(parent_bs, errp); + if (ret < 0) { + goto out; } - QLIST_INSERT_HEAD(&parent_bs->children, child, next); +out: + tran_finalize(tran, ret); + + bdrv_unref(child_bs); + return child; } -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Split part of bdrv_replace_node_common() to be used separately. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-21-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 50 +++++++++++++++++++++++++++++++------------------- 1 file changed, 31 insertions(+), 19 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static bool should_update_child(BdrvChild *c, BlockDriverState *to) return ret; } +static int bdrv_replace_node_noperm(BlockDriverState *from, + BlockDriverState *to, + bool auto_skip, Transaction *tran, + Error **errp) +{ + BdrvChild *c, *next; + + QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) { + assert(c->bs == from); + if (!should_update_child(c, to)) { + if (auto_skip) { + continue; + } + error_setg(errp, "Should not change '%s' link to '%s'", + c->name, from->node_name); + return -EINVAL; + } + if (c->frozen) { + error_setg(errp, "Cannot change '%s' link to '%s'", + c->name, from->node_name); + return -EPERM; + } + bdrv_replace_child_safe(c, to, tran); + } + + return 0; +} + /* * With auto_skip=true bdrv_replace_node_common skips updating from parents * if it creates a parent-child relation loop or if parent is block-job. @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_common(BlockDriverState *from, BlockDriverState *to, bool auto_skip, Error **errp) { - BdrvChild *c, *next; Transaction *tran = tran_new(); g_autoptr(GHashTable) found = NULL; g_autoptr(GSList) refresh_list = NULL; @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_common(BlockDriverState *from, * permissions based on new graph. If we fail, we'll roll-back the * replacement. */ - QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) { - assert(c->bs == from); - if (!should_update_child(c, to)) { - if (auto_skip) { - continue; - } - ret = -EINVAL; - error_setg(errp, "Should not change '%s' link to '%s'", - c->name, from->node_name); - goto out; - } - if (c->frozen) { - ret = -EPERM; - error_setg(errp, "Cannot change '%s' link to '%s'", - c->name, from->node_name); - goto out; - } - bdrv_replace_child_safe(c, to, tran); + ret = bdrv_replace_node_noperm(from, to, auto_skip, tran, errp); + if (ret < 0) { + goto out; } found = g_hash_table_new(NULL, NULL); -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> bdrv_append is not very good for inserting filters: it does extra permission update as part of bdrv_set_backing_hd(). During this update filter may conflict with other parents of top_bs. Instead, let's first do all graph modifications and after it update permissions. append-greedy-filter test-case in test-bdrv-graph-mod is now works, so move it out of debug option. Note: bdrv_append() is still only works for backing-child based filters. It's something to improve later. Note2: we use the fact that bdrv_append() is used to append new nodes, without backing child, so we don't need frozen check and inherits_from logic from bdrv_set_backing_hd(). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-22-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 27 ++++++++++++++++++++------- tests/unit/test-bdrv-graph-mod.c | 17 ++--------------- 2 files changed, 22 insertions(+), 22 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, * This will modify the BlockDriverState fields, and swap contents * between bs_new and bs_top. Both bs_new and bs_top are modified. * - * bs_new must not be attached to a BlockBackend. + * bs_new must not be attached to a BlockBackend and must not have backing + * child. * * This function does not create any image files. */ int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top, Error **errp) { - int ret = bdrv_set_backing_hd(bs_new, bs_top, errp); + int ret; + Transaction *tran = tran_new(); + + assert(!bs_new->backing); + + ret = bdrv_attach_child_noperm(bs_new, bs_top, "backing", + &child_of_bds, bdrv_backing_role(bs_new), + &bs_new->backing, tran, errp); if (ret < 0) { - return ret; + goto out; } - ret = bdrv_replace_node(bs_top, bs_new, errp); + ret = bdrv_replace_node_noperm(bs_top, bs_new, true, tran, errp); if (ret < 0) { - bdrv_set_backing_hd(bs_new, NULL, &error_abort); - return ret; + goto out; } - return 0; + ret = bdrv_refresh_perms(bs_new, errp); +out: + tran_finalize(tran, ret); + + bdrv_refresh_limits(bs_top, NULL); + + return ret; } static void bdrv_delete(BlockDriverState *bs) diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-graph-mod.c +++ b/tests/unit/test-bdrv-graph-mod.c @@ -XXX,XX +XXX,XX @@ static void test_append_greedy_filter(void) int main(int argc, char *argv[]) { - int i; - bool debug = false; - - for (i = 1; i < argc; i++) { - if (!strcmp(argv[i], "-d")) { - debug = true; - break; - } - } - bdrv_init(); qemu_init_main_loop(&error_abort); @@ -XXX,XX +XXX,XX @@ int main(int argc, char *argv[]) test_parallel_perm_update); g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write", test_parallel_exclusive_write); - - if (debug) { - g_test_add_func("/bdrv-graph-mod/append-greedy-filter", - test_append_greedy_filter); - } + g_test_add_func("/bdrv-graph-mod/append-greedy-filter", + test_append_greedy_filter); return g_test_run(); } -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-23-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 82 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) } } +static void bdrv_child_free(void *opaque) +{ + BdrvChild *c = opaque; + + g_free(c->name); + g_free(c); +} + static void bdrv_remove_empty_child(BdrvChild *child) { assert(!child->bs); QLIST_SAFE_REMOVE(child, next); - g_free(child->name); - g_free(child); + bdrv_child_free(child); } typedef struct BdrvAttachChildCommonState { @@ -XXX,XX +XXX,XX @@ static bool should_update_child(BdrvChild *c, BlockDriverState *to) return ret; } +typedef struct BdrvRemoveFilterOrCowChild { + BdrvChild *child; + bool is_backing; +} BdrvRemoveFilterOrCowChild; + +static void bdrv_remove_filter_or_cow_child_abort(void *opaque) +{ + BdrvRemoveFilterOrCowChild *s = opaque; + BlockDriverState *parent_bs = s->child->opaque; + + QLIST_INSERT_HEAD(&parent_bs->children, s->child, next); + if (s->is_backing) { + parent_bs->backing = s->child; + } else { + parent_bs->file = s->child; + } + + /* + * We don't have to restore child->bs here to undo bdrv_replace_child() + * because that function is transactionable and it registered own completion + * entries in @tran, so .abort() for bdrv_replace_child_safe() will be + * called automatically. + */ +} + +static void bdrv_remove_filter_or_cow_child_commit(void *opaque) +{ + BdrvRemoveFilterOrCowChild *s = opaque; + + bdrv_child_free(s->child); +} + +static TransactionActionDrv bdrv_remove_filter_or_cow_child_drv = { + .abort = bdrv_remove_filter_or_cow_child_abort, + .commit = bdrv_remove_filter_or_cow_child_commit, + .clean = g_free, +}; + +/* + * A function to remove backing-chain child of @bs if exists: cow child for + * format nodes (always .backing) and filter child for filters (may be .file or + * .backing) + */ +__attribute__((unused)) +static void bdrv_remove_filter_or_cow_child(BlockDriverState *bs, + Transaction *tran) +{ + BdrvRemoveFilterOrCowChild *s; + BdrvChild *child = bdrv_filter_or_cow_child(bs); + + if (!child) { + return; + } + + if (child->bs) { + bdrv_replace_child_safe(child, NULL, tran); + } + + s = g_new(BdrvRemoveFilterOrCowChild, 1); + *s = (BdrvRemoveFilterOrCowChild) { + .child = child, + .is_backing = (child == bs->backing), + }; + tran_add(tran, &bdrv_remove_filter_or_cow_child_drv, s); + + QLIST_SAFE_REMOVE(child, next); + if (s->is_backing) { + bs->backing = NULL; + } else { + bs->file = NULL; + } +} + static int bdrv_replace_node_noperm(BlockDriverState *from, BlockDriverState *to, bool auto_skip, Transaction *tran, -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Using bdrv_replace_node() for removing filter is not good enough: it keeps child reference of the filter, which may conflict with original top node during permission update. Instead let's create new interface, which will do all graph modifications first and then update permissions. Let's modify bdrv_replace_node_common(), allowing it additionally drop backing chain child link pointing to new node. This is quite appropriate for bdrv_drop_intermediate() and makes possible to add new bdrv_drop_filter() as a simple wrapper. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-24-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block.h | 1 + block.c | 43 +++++++++++++++++++++++++++++++++++++++---- 2 files changed, 40 insertions(+), 4 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -XXX,XX +XXX,XX @@ int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, Error **errp); BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *node_options, int flags, Error **errp); +int bdrv_drop_filter(BlockDriverState *bs, Error **errp); int bdrv_parse_aio(const char *mode, int *flags); int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough); diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static TransactionActionDrv bdrv_remove_filter_or_cow_child_drv = { * format nodes (always .backing) and filter child for filters (may be .file or * .backing) */ -__attribute__((unused)) static void bdrv_remove_filter_or_cow_child(BlockDriverState *bs, Transaction *tran) { @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_noperm(BlockDriverState *from, * * With auto_skip=false the error is returned if from has a parent which should * not be updated. + * + * With @detach_subchain=true @to must be in a backing chain of @from. In this + * case backing link of the cow-parent of @to is removed. */ static int bdrv_replace_node_common(BlockDriverState *from, BlockDriverState *to, - bool auto_skip, Error **errp) + bool auto_skip, bool detach_subchain, + Error **errp) { Transaction *tran = tran_new(); g_autoptr(GHashTable) found = NULL; g_autoptr(GSList) refresh_list = NULL; + BlockDriverState *to_cow_parent; int ret; + if (detach_subchain) { + assert(bdrv_chain_contains(from, to)); + assert(from != to); + for (to_cow_parent = from; + bdrv_filter_or_cow_bs(to_cow_parent) != to; + to_cow_parent = bdrv_filter_or_cow_bs(to_cow_parent)) + { + ; + } + } + /* Make sure that @from doesn't go away until we have successfully attached * all of its parents to @to. */ bdrv_ref(from); @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_common(BlockDriverState *from, goto out; } + if (detach_subchain) { + bdrv_remove_filter_or_cow_child(to_cow_parent, tran); + } + found = g_hash_table_new(NULL, NULL); refresh_list = bdrv_topological_dfs(refresh_list, found, to); @@ -XXX,XX +XXX,XX @@ out: int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, Error **errp) { - return bdrv_replace_node_common(from, to, true, errp); + return bdrv_replace_node_common(from, to, true, false, errp); +} + +int bdrv_drop_filter(BlockDriverState *bs, Error **errp) +{ + return bdrv_replace_node_common(bs, bdrv_filter_or_cow_bs(bs), true, true, + errp); } /* @@ -XXX,XX +XXX,XX @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, updated_children = g_slist_prepend(updated_children, c); } - bdrv_replace_node_common(top, base, false, &local_err); + /* + * It seems correct to pass detach_subchain=true here, but it triggers + * one more yet not fixed bug, when due to nested aio_poll loop we switch to + * another drained section, which modify the graph (for example, removing + * the child, which we keep in updated_children list). So, it's a TODO. + * + * Note, bug triggered if pass detach_subchain=true here and run + * test-bdrv-drain. test_drop_intermediate_poll() test-case will crash. + * That's a FIXME. + */ + bdrv_replace_node_common(top, base, false, false, &local_err); if (local_err) { error_report_err(local_err); goto exit; -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> We don't need this workaround anymore: bdrv_append is already smart enough and we can use new bdrv_drop_filter(). This commit efficiently reverts also recent 705dde27c6c53b73, which checked .active on io path. Still it said that the problem should be theoretical. And the logic of filter removement is changed anyway. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-25-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/backup-top.c | 47 +------------------------------------- tests/qemu-iotests/283.out | 2 +- 2 files changed, 2 insertions(+), 47 deletions(-) diff --git a/block/backup-top.c b/block/backup-top.c index XXXXXXX..XXXXXXX 100644 --- a/block/backup-top.c +++ b/block/backup-top.c @@ -XXX,XX +XXX,XX @@ typedef struct BDRVBackupTopState { BlockCopyState *bcs; BdrvChild *target; - bool active; int64_t cluster_size; } BDRVBackupTopState; @@ -XXX,XX +XXX,XX @@ static coroutine_fn int backup_top_co_preadv( BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) { - BDRVBackupTopState *s = bs->opaque; - - if (!s->active) { - return -EIO; - } - return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); } @@ -XXX,XX +XXX,XX @@ static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset, BDRVBackupTopState *s = bs->opaque; uint64_t off, end; - if (!s->active) { - return -EIO; - } - if (flags & BDRV_REQ_WRITE_UNCHANGED) { return 0; } @@ -XXX,XX +XXX,XX @@ static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c, uint64_t perm, uint64_t shared, uint64_t *nperm, uint64_t *nshared) { - BDRVBackupTopState *s = bs->opaque; - - if (!s->active) { - /* - * The filter node may be in process of bdrv_append(), which firstly do - * bdrv_set_backing_hd() and then bdrv_replace_node(). This means that - * we can't unshare BLK_PERM_WRITE during bdrv_append() operation. So, - * let's require nothing during bdrv_append() and refresh permissions - * after it (see bdrv_backup_top_append()). - */ - *nperm = 0; - *nshared = BLK_PERM_ALL; - return; - } - if (!(role & BDRV_CHILD_FILTERED)) { /* * Target child @@ -XXX,XX +XXX,XX @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, } appended = true; - /* - * bdrv_append() finished successfully, now we can require permissions - * we want. - */ - state->active = true; - ret = bdrv_child_refresh_perms(top, top->backing, errp); - if (ret < 0) { - error_prepend(errp, "Cannot set permissions for backup-top filter: "); - goto fail; - } - state->cluster_size = cluster_size; state->bcs = block_copy_state_new(top->backing, state->target, cluster_size, perf->use_copy_range, @@ -XXX,XX +XXX,XX @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, fail: if (appended) { - state->active = false; bdrv_backup_top_drop(top); } else { bdrv_unref(top); @@ -XXX,XX +XXX,XX @@ void bdrv_backup_top_drop(BlockDriverState *bs) { BDRVBackupTopState *s = bs->opaque; - bdrv_drained_begin(bs); + bdrv_drop_filter(bs, &error_abort); block_copy_state_free(s->bcs); - s->active = false; - bdrv_child_refresh_perms(bs, bs->backing, &error_abort); - bdrv_replace_node(bs, bs->backing->bs, &error_abort); - bdrv_set_backing_hd(bs, NULL, &error_abort); - - bdrv_drained_end(bs); - bdrv_unref(bs); } diff --git a/tests/qemu-iotests/283.out b/tests/qemu-iotests/283.out index XXXXXXX..XXXXXXX 100644 --- a/tests/qemu-iotests/283.out +++ b/tests/qemu-iotests/283.out @@ -XXX,XX +XXX,XX @@ {"execute": "blockdev-add", "arguments": {"driver": "blkdebug", "image": "base", "node-name": "other", "take-child-perms": ["write"]}} {"return": {}} {"execute": "blockdev-backup", "arguments": {"device": "source", "sync": "full", "target": "target"}} -{"error": {"class": "GenericError", "desc": "Cannot set permissions for backup-top filter: Conflicts with use by source as 'image', which does not allow 'write' on base"}} +{"error": {"class": "GenericError", "desc": "Cannot append backup-top filter: Conflicts with use by source as 'image', which does not allow 'write' on base"}} === backup-top should be gone after job-finalize === -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> This argument is always NULL. Drop it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-26-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 38 +++++++++++--------------------------- 1 file changed, 11 insertions(+), 27 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_fill_options(QDict **options, const char *filename, static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, uint64_t new_used_perm, uint64_t new_shared_perm, - GSList *ignore_children, Error **errp); typedef struct BlockReopenQueueEntry { @@ -XXX,XX +XXX,XX @@ static bool bdrv_a_allow_b(BdrvChild *a, BdrvChild *b, Error **errp) return false; } -static bool bdrv_parent_perms_conflict(BlockDriverState *bs, - GSList *ignore_children, - Error **errp) +static bool bdrv_parent_perms_conflict(BlockDriverState *bs, Error **errp) { BdrvChild *a, *b; @@ -XXX,XX +XXX,XX @@ static bool bdrv_parent_perms_conflict(BlockDriverState *bs, * directions. */ QLIST_FOREACH(a, &bs->parents, next_parent) { - if (g_slist_find(ignore_children, a)) { - continue; - } - QLIST_FOREACH(b, &bs->parents, next_parent) { - if (a == b || g_slist_find(ignore_children, b)) { + if (a == b) { continue; } @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_safe(BdrvChild *child, BlockDriverState *new_bs, static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q, uint64_t cumulative_perms, uint64_t cumulative_shared_perms, - GSList *ignore_children, Transaction *tran, Error **errp) { BlockDriver *drv = bs->drv; @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm_common(GSList *list, BlockReopenQueue *q, bool use_cumulative_perms, uint64_t cumulative_perms, uint64_t cumulative_shared_perms, - GSList *ignore_children, Transaction *tran, Error **errp) { int ret; @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm_common(GSList *list, BlockReopenQueue *q, ret = bdrv_node_check_perm(bs, q, cumulative_perms, cumulative_shared_perms, - ignore_children, tran, errp); + tran, errp); if (ret < 0) { return ret; } @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm_common(GSList *list, BlockReopenQueue *q, for ( ; list; list = list->next) { bs = list->data; - if (bdrv_parent_perms_conflict(bs, ignore_children, errp)) { + if (bdrv_parent_perms_conflict(bs, errp)) { return -EINVAL; } @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm_common(GSList *list, BlockReopenQueue *q, ret = bdrv_node_check_perm(bs, q, cumulative_perms, cumulative_shared_perms, - ignore_children, tran, errp); + tran, errp); if (ret < 0) { return ret; } @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm_common(GSList *list, BlockReopenQueue *q, static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, uint64_t cumulative_perms, - uint64_t cumulative_shared_perms, - GSList *ignore_children, Error **errp) + uint64_t cumulative_shared_perms, Error **errp) { g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); return bdrv_check_perm_common(list, q, true, cumulative_perms, - cumulative_shared_perms, ignore_children, - NULL, errp); + cumulative_shared_perms, NULL, errp); } static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, Transaction *tran, Error **errp) { - return bdrv_check_perm_common(list, q, false, 0, 0, NULL, tran, errp); + return bdrv_check_perm_common(list, q, false, 0, 0, tran, errp); } /* @@ -XXX,XX +XXX,XX @@ char *bdrv_perm_names(uint64_t perm) static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, uint64_t new_used_perm, uint64_t new_shared_perm, - GSList *ignore_children, Error **errp) { BdrvChild *c; @@ -XXX,XX +XXX,XX @@ static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED); QLIST_FOREACH(c, &bs->parents, next_parent) { - if (g_slist_find(ignore_children, c)) { - continue; - } - if ((new_used_perm & c->shared_perm) != new_used_perm) { char *user = bdrv_child_user_desc(c); char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm); @@ -XXX,XX +XXX,XX @@ static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, } return bdrv_check_perm(bs, q, cumulative_perms, cumulative_shared_perms, - ignore_children, errp); + errp); } static int bdrv_refresh_perms(BlockDriverState *bs, Error **errp) @@ -XXX,XX +XXX,XX @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) QTAILQ_FOREACH(bs_entry, bs_queue, entry) { BDRVReopenState *state = &bs_entry->state; ret = bdrv_check_perm(state->bs, bs_queue, state->perm, - state->shared_perm, NULL, errp); + state->shared_perm, errp); if (ret < 0) { goto cleanup_perm; } @@ -XXX,XX +XXX,XX @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) bs_queue, state->perm, state->shared_perm, &nperm, &nshared); ret = bdrv_check_update_perm(state->new_backing_bs, NULL, - nperm, nshared, NULL, errp); + nperm, nshared, errp); if (ret < 0) { goto cleanup_perm; } -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> To be used in the further commit. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-27-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 46 ++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 42 insertions(+), 4 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ void bdrv_root_unref_child(BdrvChild *child) bdrv_unref(child_bs); } +typedef struct BdrvSetInheritsFrom { + BlockDriverState *bs; + BlockDriverState *old_inherits_from; +} BdrvSetInheritsFrom; + +static void bdrv_set_inherits_from_abort(void *opaque) +{ + BdrvSetInheritsFrom *s = opaque; + + s->bs->inherits_from = s->old_inherits_from; +} + +static TransactionActionDrv bdrv_set_inherits_from_drv = { + .abort = bdrv_set_inherits_from_abort, + .clean = g_free, +}; + +/* @tran is allowed to be NULL. In this case no rollback is possible */ +static void bdrv_set_inherits_from(BlockDriverState *bs, + BlockDriverState *new_inherits_from, + Transaction *tran) +{ + if (tran) { + BdrvSetInheritsFrom *s = g_new(BdrvSetInheritsFrom, 1); + + *s = (BdrvSetInheritsFrom) { + .bs = bs, + .old_inherits_from = bs->inherits_from, + }; + + tran_add(tran, &bdrv_set_inherits_from_drv, s); + } + + bs->inherits_from = new_inherits_from; +} + /** * Clear all inherits_from pointers from children and grandchildren of * @root that point to @root, where necessary. + * @tran is allowed to be NULL. In this case no rollback is possible */ -static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child) +static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child, + Transaction *tran) { BdrvChild *c; @@ -XXX,XX +XXX,XX @@ static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child) } } if (c == NULL) { - child->bs->inherits_from = NULL; + bdrv_set_inherits_from(child->bs, NULL, tran); } } QLIST_FOREACH(c, &child->bs->children, next) { - bdrv_unset_inherits_from(root, c); + bdrv_unset_inherits_from(root, c, tran); } } @@ -XXX,XX +XXX,XX @@ void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) return; } - bdrv_unset_inherits_from(parent, child); + bdrv_unset_inherits_from(parent, child, NULL); bdrv_root_unref_child(child); } -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> To be used in further commit. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-28-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block.h | 3 ++- block.c | 9 ++++----- block/io.c | 31 +++++++++++++++++++++++++++++-- 3 files changed, 35 insertions(+), 8 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -XXX,XX +XXX,XX @@ #include "block/dirty-bitmap.h" #include "block/blockjob.h" #include "qemu/hbitmap.h" +#include "qemu/transactions.h" /* * generated_co_wrapper @@ -XXX,XX +XXX,XX @@ int64_t bdrv_get_allocated_file_size(BlockDriverState *bs); BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts, BlockDriverState *in_bs, Error **errp); void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr); -void bdrv_refresh_limits(BlockDriverState *bs, Error **errp); +void bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp); int bdrv_commit(BlockDriverState *bs); int bdrv_make_empty(BdrvChild *c, Error **errp); int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file, diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ #include "qemu/timer.h" #include "qemu/cutils.h" #include "qemu/id.h" -#include "qemu/transactions.h" #include "block/coroutines.h" #ifdef CONFIG_BSD @@ -XXX,XX +XXX,XX @@ static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv, return ret; } - bdrv_refresh_limits(bs, &local_err); + bdrv_refresh_limits(bs, NULL, &local_err); if (local_err) { error_propagate(errp, local_err); return -EINVAL; @@ -XXX,XX +XXX,XX @@ int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, } out: - bdrv_refresh_limits(bs, NULL); + bdrv_refresh_limits(bs, NULL, NULL); return ret; } @@ -XXX,XX +XXX,XX @@ static void bdrv_reopen_commit(BDRVReopenState *reopen_state) bdrv_set_backing_hd(bs, reopen_state->new_backing_bs, &error_abort); } - bdrv_refresh_limits(bs, NULL); + bdrv_refresh_limits(bs, NULL, NULL); } /* @@ -XXX,XX +XXX,XX @@ int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top, out: tran_finalize(tran, ret); - bdrv_refresh_limits(bs_top, NULL); + bdrv_refresh_limits(bs_top, NULL, NULL); return ret; } diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov); } -void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) +typedef struct BdrvRefreshLimitsState { + BlockDriverState *bs; + BlockLimits old_bl; +} BdrvRefreshLimitsState; + +static void bdrv_refresh_limits_abort(void *opaque) +{ + BdrvRefreshLimitsState *s = opaque; + + s->bs->bl = s->old_bl; +} + +static TransactionActionDrv bdrv_refresh_limits_drv = { + .abort = bdrv_refresh_limits_abort, + .clean = g_free, +}; + +/* @tran is allowed to be NULL, in this case no rollback is possible. */ +void bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp) { ERRP_GUARD(); BlockDriver *drv = bs->drv; BdrvChild *c; bool have_limits; + if (tran) { + BdrvRefreshLimitsState *s = g_new(BdrvRefreshLimitsState, 1); + *s = (BdrvRefreshLimitsState) { + .bs = bs, + .old_bl = bs->bl, + }; + tran_add(tran, &bdrv_refresh_limits_drv, s); + } + memset(&bs->bl, 0, sizeof(bs->bl)); if (!drv) { @@ -XXX,XX +XXX,XX @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) QLIST_FOREACH(c, &bs->children, next) { if (c->role & (BDRV_CHILD_DATA | BDRV_CHILD_FILTERED | BDRV_CHILD_COW)) { - bdrv_refresh_limits(c->bs, errp); + bdrv_refresh_limits(c->bs, tran, errp); if (*errp) { return; } -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Split out no-perm part of bdrv_set_backing_hd() as a separate transaction action. Note the in case of existing BdrvChild we reuse it, not recreate, just to do less actions. We don't need to create extra reference to backing_hd as we don't lose it in bdrv_attach_child(). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-29-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 54 +++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 37 insertions(+), 17 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_attach_child_noperm(BlockDriverState *parent_bs, BdrvChild **child, Transaction *tran, Error **errp); +static void bdrv_remove_filter_or_cow_child(BlockDriverState *bs, + Transaction *tran); static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, Error **errp); @@ -XXX,XX +XXX,XX @@ static BdrvChildRole bdrv_backing_role(BlockDriverState *bs) * Sets the bs->backing link of a BDS. A new reference is created; callers * which don't need their own reference any more must call bdrv_unref(). */ -int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, - Error **errp) +static int bdrv_set_backing_noperm(BlockDriverState *bs, + BlockDriverState *backing_hd, + Transaction *tran, Error **errp) { int ret = 0; bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) && @@ -XXX,XX +XXX,XX @@ int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, return -EPERM; } - if (backing_hd) { - bdrv_ref(backing_hd); - } - if (bs->backing) { /* Cannot be frozen, we checked that above */ - bdrv_unref_child(bs, bs->backing); - bs->backing = NULL; + bdrv_unset_inherits_from(bs, bs->backing, tran); + bdrv_remove_filter_or_cow_child(bs, tran); } if (!backing_hd) { goto out; } - bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_of_bds, - bdrv_backing_role(bs), errp); - if (!bs->backing) { - ret = -EPERM; - goto out; + ret = bdrv_attach_child_noperm(bs, backing_hd, "backing", + &child_of_bds, bdrv_backing_role(bs), + &bs->backing, tran, errp); + if (ret < 0) { + return ret; } - /* If backing_hd was already part of bs's backing chain, and + + /* + * If backing_hd was already part of bs's backing chain, and * inherits_from pointed recursively to bs then let's update it to - * point directly to bs (else it will become NULL). */ + * point directly to bs (else it will become NULL). + */ if (update_inherits_from) { - backing_hd->inherits_from = bs; + bdrv_set_inherits_from(backing_hd, bs, tran); } out: - bdrv_refresh_limits(bs, NULL, NULL); + bdrv_refresh_limits(bs, tran, NULL); + + return 0; +} + +int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, + Error **errp) +{ + int ret; + Transaction *tran = tran_new(); + + ret = bdrv_set_backing_noperm(bs, backing_hd, tran, errp); + if (ret < 0) { + goto out; + } + + ret = bdrv_refresh_perms(bs, errp); +out: + tran_finalize(tran, ret); return ret; } -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> During reopen we may add backing bs from other aio context, which may lead to changing original context of top bs. We are going to move graph modification to prepare stage. So, it will be possible that bdrv_flush() in bdrv_reopen_prepare called on bs in non-original aio context, which we didn't aquire which leads to crash. To avoid this problem move bdrv_flush() to be a separate reopen stage before bdrv_reopen_prepare(). This doesn't seem correct to acquire only one aio context and not all contexts participating in reopen. But it's not obvious how to do it correctly, keeping in mind: 1. rules of bdrv_set_aio_context_ignore() that requires new_context lock not being held 2. possible deadlocks because of holding all (or several?) AioContext locks Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-30-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) assert(bs_queue != NULL); + QTAILQ_FOREACH(bs_entry, bs_queue, entry) { + ret = bdrv_flush(bs_entry->state.bs); + if (ret < 0) { + error_setg_errno(errp, -ret, "Error flushing drive"); + goto cleanup; + } + } + QTAILQ_FOREACH(bs_entry, bs_queue, entry) { assert(bs_entry->state.bs->quiesce_counter > 0); if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, errp)) { @@ -XXX,XX +XXX,XX @@ static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, bdrv_reopen_perm(queue, reopen_state->bs, &reopen_state->perm, &reopen_state->shared_perm); - ret = bdrv_flush(reopen_state->bs); - if (ret) { - error_setg_errno(errp, -ret, "Error flushing drive"); - goto error; - } - if (drv->bdrv_reopen_prepare) { /* * If a driver-specific option is missing, it means that we -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Move bdrv_reopen_multiple to new paradigm of permission update: first update graph relations, then do refresh the permissions. We have to modify reopen process in file-posix driver: with new scheme we don't have prepared permissions in raw_reopen_prepare(), so we should reconfigure fd in raw_check_perm(). Still this seems more native and simple anyway. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-31-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block.h | 3 +- block.c | 187 ++++++++++++------------------------------ block/file-posix.c | 91 +++++++------------- 3 files changed, 84 insertions(+), 197 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -XXX,XX +XXX,XX @@ typedef struct BDRVReopenState { BlockdevDetectZeroesOptions detect_zeroes; bool backing_missing; bool replace_backing_bs; /* new_backing_bs is ignored if this is false */ - BlockDriverState *new_backing_bs; /* If NULL then detach the current bs */ - uint64_t perm, shared_perm; + BlockDriverState *old_backing_bs; /* keep pointer for permissions update */ QDict *options; QDict *explicit_options; void *opaque; diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_attach_child_noperm(BlockDriverState *parent_bs, static void bdrv_remove_filter_or_cow_child(BlockDriverState *bs, Transaction *tran); -static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue - *queue, Error **errp); +static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, + BlockReopenQueue *queue, + Transaction *set_backings_tran, Error **errp); static void bdrv_reopen_commit(BDRVReopenState *reopen_state); static void bdrv_reopen_abort(BDRVReopenState *reopen_state); @@ -XXX,XX +XXX,XX @@ static void bdrv_list_abort_perm_update(GSList *list) } } +__attribute__((unused)) static void bdrv_abort_perm_update(BlockDriverState *bs) { g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); @@ -XXX,XX +XXX,XX @@ char *bdrv_perm_names(uint64_t perm) * * Needs to be followed by a call to either bdrv_set_perm() or * bdrv_abort_perm_update(). */ +__attribute__((unused)) static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, uint64_t new_used_perm, uint64_t new_shared_perm, @@ -XXX,XX +XXX,XX @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, bs_entry->state.explicit_options = explicit_options; bs_entry->state.flags = flags; - /* This needs to be overwritten in bdrv_reopen_prepare() */ - bs_entry->state.perm = UINT64_MAX; - bs_entry->state.shared_perm = 0; - /* * If keep_old_opts is false then it means that unspecified * options must be reset to their original value. We don't allow @@ -XXX,XX +XXX,XX @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) { int ret = -1; BlockReopenQueueEntry *bs_entry, *next; + Transaction *tran = tran_new(); + g_autoptr(GHashTable) found = NULL; + g_autoptr(GSList) refresh_list = NULL; assert(bs_queue != NULL); @@ -XXX,XX +XXX,XX @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) QTAILQ_FOREACH(bs_entry, bs_queue, entry) { assert(bs_entry->state.bs->quiesce_counter > 0); - if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, errp)) { - goto cleanup; + ret = bdrv_reopen_prepare(&bs_entry->state, bs_queue, tran, errp); + if (ret < 0) { + goto abort; } bs_entry->prepared = true; } + found = g_hash_table_new(NULL, NULL); QTAILQ_FOREACH(bs_entry, bs_queue, entry) { BDRVReopenState *state = &bs_entry->state; - ret = bdrv_check_perm(state->bs, bs_queue, state->perm, - state->shared_perm, errp); - if (ret < 0) { - goto cleanup_perm; - } - /* Check if new_backing_bs would accept the new permissions */ - if (state->replace_backing_bs && state->new_backing_bs) { - uint64_t nperm, nshared; - bdrv_child_perm(state->bs, state->new_backing_bs, - NULL, bdrv_backing_role(state->bs), - bs_queue, state->perm, state->shared_perm, - &nperm, &nshared); - ret = bdrv_check_update_perm(state->new_backing_bs, NULL, - nperm, nshared, errp); - if (ret < 0) { - goto cleanup_perm; - } + + refresh_list = bdrv_topological_dfs(refresh_list, found, state->bs); + if (state->old_backing_bs) { + refresh_list = bdrv_topological_dfs(refresh_list, found, + state->old_backing_bs); } - bs_entry->perms_checked = true; + } + + /* + * Note that file-posix driver rely on permission update done during reopen + * (even if no permission changed), because it wants "new" permissions for + * reconfiguring the fd and that's why it does it in raw_check_perm(), not + * in raw_reopen_prepare() which is called with "old" permissions. + */ + ret = bdrv_list_refresh_perms(refresh_list, bs_queue, tran, errp); + if (ret < 0) { + goto abort; } /* @@ -XXX,XX +XXX,XX @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) bdrv_reopen_commit(&bs_entry->state); } - ret = 0; -cleanup_perm: - QTAILQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { - BDRVReopenState *state = &bs_entry->state; - - if (!bs_entry->perms_checked) { - continue; - } - - if (ret == 0) { - uint64_t perm, shared; + tran_commit(tran); - bdrv_get_cumulative_perm(state->bs, &perm, &shared); - assert(perm == state->perm); - assert(shared == state->shared_perm); + QTAILQ_FOREACH_REVERSE(bs_entry, bs_queue, entry) { + BlockDriverState *bs = bs_entry->state.bs; - bdrv_set_perm(state->bs); - } else { - bdrv_abort_perm_update(state->bs); - if (state->replace_backing_bs && state->new_backing_bs) { - bdrv_abort_perm_update(state->new_backing_bs); - } + if (bs->drv->bdrv_reopen_commit_post) { + bs->drv->bdrv_reopen_commit_post(&bs_entry->state); } } - if (ret == 0) { - QTAILQ_FOREACH_REVERSE(bs_entry, bs_queue, entry) { - BlockDriverState *bs = bs_entry->state.bs; + ret = 0; + goto cleanup; - if (bs->drv->bdrv_reopen_commit_post) - bs->drv->bdrv_reopen_commit_post(&bs_entry->state); +abort: + tran_abort(tran); + QTAILQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { + if (bs_entry->prepared) { + bdrv_reopen_abort(&bs_entry->state); } + qobject_unref(bs_entry->state.explicit_options); + qobject_unref(bs_entry->state.options); } + cleanup: QTAILQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { - if (ret) { - if (bs_entry->prepared) { - bdrv_reopen_abort(&bs_entry->state); - } - qobject_unref(bs_entry->state.explicit_options); - qobject_unref(bs_entry->state.options); - } - if (bs_entry->state.new_backing_bs) { - bdrv_unref(bs_entry->state.new_backing_bs); - } g_free(bs_entry); } g_free(bs_queue); @@ -XXX,XX +XXX,XX @@ int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only, return ret; } -static BlockReopenQueueEntry *find_parent_in_reopen_queue(BlockReopenQueue *q, - BdrvChild *c) -{ - BlockReopenQueueEntry *entry; - - QTAILQ_FOREACH(entry, q, entry) { - BlockDriverState *bs = entry->state.bs; - BdrvChild *child; - - QLIST_FOREACH(child, &bs->children, next) { - if (child == c) { - return entry; - } - } - } - - return NULL; -} - -static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs, - uint64_t *perm, uint64_t *shared) -{ - BdrvChild *c; - BlockReopenQueueEntry *parent; - uint64_t cumulative_perms = 0; - uint64_t cumulative_shared_perms = BLK_PERM_ALL; - - QLIST_FOREACH(c, &bs->parents, next_parent) { - parent = find_parent_in_reopen_queue(q, c); - if (!parent) { - cumulative_perms |= c->perm; - cumulative_shared_perms &= c->shared_perm; - } else { - uint64_t nperm, nshared; - - bdrv_child_perm(parent->state.bs, bs, c, c->role, q, - parent->state.perm, parent->state.shared_perm, - &nperm, &nshared); - - cumulative_perms |= nperm; - cumulative_shared_perms &= nshared; - } - } - *perm = cumulative_perms; - *shared = cumulative_shared_perms; -} - static bool bdrv_reopen_can_attach(BlockDriverState *parent, BdrvChild *child, BlockDriverState *new_child, @@ -XXX,XX +XXX,XX @@ static bool bdrv_reopen_can_attach(BlockDriverState *parent, * Return 0 on success, otherwise return < 0 and set @errp. */ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state, + Transaction *set_backings_tran, Error **errp) { BlockDriverState *bs = reopen_state->bs; @@ -XXX,XX +XXX,XX @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state, /* If we want to replace the backing file we need some extra checks */ if (new_backing_bs != bdrv_filter_or_cow_bs(overlay_bs)) { + int ret; + /* Check for implicit nodes between bs and its backing file */ if (bs != overlay_bs) { error_setg(errp, "Cannot change backing link if '%s' has " @@ -XXX,XX +XXX,XX @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state, return -EPERM; } reopen_state->replace_backing_bs = true; - if (new_backing_bs) { - bdrv_ref(new_backing_bs); - reopen_state->new_backing_bs = new_backing_bs; + reopen_state->old_backing_bs = bs->backing ? bs->backing->bs : NULL; + ret = bdrv_set_backing_noperm(bs, new_backing_bs, set_backings_tran, + errp); + if (ret < 0) { + return ret; } } @@ -XXX,XX +XXX,XX @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state, * */ static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, - BlockReopenQueue *queue, Error **errp) + BlockReopenQueue *queue, + Transaction *set_backings_tran, Error **errp) { int ret = -1; int old_flags; @@ -XXX,XX +XXX,XX @@ static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, goto error; } - /* Calculate required permissions after reopening */ - bdrv_reopen_perm(queue, reopen_state->bs, - &reopen_state->perm, &reopen_state->shared_perm); - if (drv->bdrv_reopen_prepare) { /* * If a driver-specific option is missing, it means that we @@ -XXX,XX +XXX,XX @@ static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, * either a reference to an existing node (using its node name) * or NULL to simply detach the current backing file. */ - ret = bdrv_reopen_parse_backing(reopen_state, errp); + ret = bdrv_reopen_parse_backing(reopen_state, set_backings_tran, errp); if (ret < 0) { goto error; } @@ -XXX,XX +XXX,XX @@ static void bdrv_reopen_commit(BDRVReopenState *reopen_state) qdict_del(bs->explicit_options, child->name); qdict_del(bs->options, child->name); } - - /* - * Change the backing file if a new one was specified. We do this - * after updating bs->options, so bdrv_refresh_filename() (called - * from bdrv_set_backing_hd()) has the new values. - */ - if (reopen_state->replace_backing_bs) { - BlockDriverState *old_backing_bs = child_bs(bs->backing); - assert(!old_backing_bs || !old_backing_bs->implicit); - /* Abort the permission update on the backing bs we're detaching */ - if (old_backing_bs) { - bdrv_abort_perm_update(old_backing_bs); - } - bdrv_set_backing_hd(bs, reopen_state->new_backing_bs, &error_abort); - } - bdrv_refresh_limits(bs, NULL, NULL); } diff --git a/block/file-posix.c b/block/file-posix.c index XXXXXXX..XXXXXXX 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -XXX,XX +XXX,XX @@ typedef struct BDRVRawState { } BDRVRawState; typedef struct BDRVRawReopenState { - int fd; int open_flags; bool drop_cache; bool check_cache_dropped; @@ -XXX,XX +XXX,XX @@ static int raw_reopen_prepare(BDRVReopenState *state, BDRVRawReopenState *rs; QemuOpts *opts; int ret; - Error *local_err = NULL; assert(state != NULL); assert(state->bs != NULL); @@ -XXX,XX +XXX,XX @@ static int raw_reopen_prepare(BDRVReopenState *state, * bdrv_reopen_prepare() will detect changes and complain. */ qemu_opts_to_qdict(opts, state->options); - rs->fd = raw_reconfigure_getfd(state->bs, state->flags, &rs->open_flags, - state->perm, true, &local_err); - if (local_err) { - error_propagate(errp, local_err); - ret = -1; - goto out; - } - - /* Fail already reopen_prepare() if we can't get a working O_DIRECT - * alignment with the new fd. */ - if (rs->fd != -1) { - raw_probe_alignment(state->bs, rs->fd, &local_err); - if (local_err) { - error_propagate(errp, local_err); - ret = -EINVAL; - goto out_fd; - } - } + /* + * As part of reopen prepare we also want to create new fd by + * raw_reconfigure_getfd(). But it wants updated "perm", when in + * bdrv_reopen_multiple() .bdrv_reopen_prepare() callback called prior to + * permission update. Happily, permission update is always a part (a seprate + * stage) of bdrv_reopen_multiple() so we can rely on this fact and + * reconfigure fd in raw_check_perm(). + */ s->reopen_state = state; ret = 0; -out_fd: - if (ret < 0) { - qemu_close(rs->fd); - rs->fd = -1; - } + out: qemu_opts_del(opts); return ret; @@ -XXX,XX +XXX,XX @@ static void raw_reopen_commit(BDRVReopenState *state) s->drop_cache = rs->drop_cache; s->check_cache_dropped = rs->check_cache_dropped; s->open_flags = rs->open_flags; - - qemu_close(s->fd); - s->fd = rs->fd; - g_free(state->opaque); state->opaque = NULL; @@ -XXX,XX +XXX,XX @@ static void raw_reopen_abort(BDRVReopenState *state) return; } - if (rs->fd >= 0) { - qemu_close(rs->fd); - rs->fd = -1; - } g_free(state->opaque); state->opaque = NULL; @@ -XXX,XX +XXX,XX @@ static int raw_check_perm(BlockDriverState *bs, uint64_t perm, uint64_t shared, Error **errp) { BDRVRawState *s = bs->opaque; - BDRVRawReopenState *rs = NULL; + int input_flags = s->reopen_state ? s->reopen_state->flags : bs->open_flags; int open_flags; int ret; - if (s->perm_change_fd) { + /* We may need a new fd if auto-read-only switches the mode */ + ret = raw_reconfigure_getfd(bs, input_flags, &open_flags, perm, + false, errp); + if (ret < 0) { + return ret; + } else if (ret != s->fd) { + Error *local_err = NULL; + /* - * In the context of reopen, this function may be called several times - * (directly and recursively while change permissions of the parent). - * This is even true for children that don't inherit from the original - * reopen node, so s->reopen_state is not set. - * - * Ignore all but the first call. + * Fail already check_perm() if we can't get a working O_DIRECT + * alignment with the new fd. */ - return 0; - } - - if (s->reopen_state) { - /* We already have a new file descriptor to set permissions for */ - assert(s->reopen_state->perm == perm); - assert(s->reopen_state->shared_perm == shared); - rs = s->reopen_state->opaque; - s->perm_change_fd = rs->fd; - s->perm_change_flags = rs->open_flags; - } else { - /* We may need a new fd if auto-read-only switches the mode */ - ret = raw_reconfigure_getfd(bs, bs->open_flags, &open_flags, perm, - false, errp); - if (ret < 0) { - return ret; - } else if (ret != s->fd) { - s->perm_change_fd = ret; - s->perm_change_flags = open_flags; + raw_probe_alignment(bs, ret, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return -EINVAL; } + + s->perm_change_fd = ret; + s->perm_change_flags = open_flags; } /* Prepare permissions on old fd to avoid conflicts between old and new, @@ -XXX,XX +XXX,XX @@ static int raw_check_perm(BlockDriverState *bs, uint64_t perm, uint64_t shared, return 0; fail: - if (s->perm_change_fd && !s->reopen_state) { + if (s->perm_change_fd) { qemu_close(s->perm_change_fd); } s->perm_change_fd = 0; @@ -XXX,XX +XXX,XX @@ static void raw_abort_perm_update(BlockDriverState *bs) /* For reopen, .bdrv_reopen_abort is called afterwards and will close * the file descriptor. */ - if (s->perm_change_fd && !s->reopen_state) { + if (s->perm_change_fd) { qemu_close(s->perm_change_fd); } s->perm_change_fd = 0; -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-32-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 103 -------------------------------------------------------- 1 file changed, 103 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_fill_options(QDict **options, const char *filename, return 0; } -static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, - uint64_t new_used_perm, - uint64_t new_shared_perm, - Error **errp); - typedef struct BlockReopenQueueEntry { bool prepared; bool perms_checked; @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm_common(GSList *list, BlockReopenQueue *q, return 0; } -static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, - uint64_t cumulative_perms, - uint64_t cumulative_shared_perms, Error **errp) -{ - g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); - return bdrv_check_perm_common(list, q, true, cumulative_perms, - cumulative_shared_perms, NULL, errp); -} - static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, Transaction *tran, Error **errp) { return bdrv_check_perm_common(list, q, false, 0, 0, tran, errp); } -/* - * Notifies drivers that after a previous bdrv_check_perm() call, the - * permission update is not performed and any preparations made for it (e.g. - * taken file locks) need to be undone. - */ -static void bdrv_node_abort_perm_update(BlockDriverState *bs) -{ - BlockDriver *drv = bs->drv; - BdrvChild *c; - - if (!drv) { - return; - } - - bdrv_drv_set_perm_abort(bs); - - QLIST_FOREACH(c, &bs->children, next) { - bdrv_child_set_perm_abort(c); - } -} - -static void bdrv_list_abort_perm_update(GSList *list) -{ - for ( ; list; list = list->next) { - bdrv_node_abort_perm_update((BlockDriverState *)list->data); - } -} - -__attribute__((unused)) -static void bdrv_abort_perm_update(BlockDriverState *bs) -{ - g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); - return bdrv_list_abort_perm_update(list); -} - static void bdrv_node_set_perm(BlockDriverState *bs) { BlockDriver *drv = bs->drv; @@ -XXX,XX +XXX,XX @@ char *bdrv_perm_names(uint64_t perm) return g_string_free(result, FALSE); } -/* - * Checks whether a new reference to @bs can be added if the new user requires - * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is - * set, the BdrvChild objects in this list are ignored in the calculations; - * this allows checking permission updates for an existing reference. - * - * Needs to be followed by a call to either bdrv_set_perm() or - * bdrv_abort_perm_update(). */ -__attribute__((unused)) -static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, - uint64_t new_used_perm, - uint64_t new_shared_perm, - Error **errp) -{ - BdrvChild *c; - uint64_t cumulative_perms = new_used_perm; - uint64_t cumulative_shared_perms = new_shared_perm; - - - /* There is no reason why anyone couldn't tolerate write_unchanged */ - assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED); - - QLIST_FOREACH(c, &bs->parents, next_parent) { - if ((new_used_perm & c->shared_perm) != new_used_perm) { - char *user = bdrv_child_user_desc(c); - char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm); - - error_setg(errp, "Conflicts with use by %s as '%s', which does not " - "allow '%s' on %s", - user, c->name, perm_names, bdrv_get_node_name(c->bs)); - g_free(user); - g_free(perm_names); - return -EPERM; - } - - if ((c->perm & new_shared_perm) != c->perm) { - char *user = bdrv_child_user_desc(c); - char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm); - - error_setg(errp, "Conflicts with use by %s as '%s', which uses " - "'%s' on %s", - user, c->name, perm_names, bdrv_get_node_name(c->bs)); - g_free(user); - g_free(perm_names); - return -EPERM; - } - - cumulative_perms |= c->perm; - cumulative_shared_perms &= c->shared_perm; - } - - return bdrv_check_perm(bs, q, cumulative_perms, cumulative_shared_perms, - errp); -} static int bdrv_refresh_perms(BlockDriverState *bs, Error **errp) { -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> bdrv_check_perm_common() has only one caller, so no more sense in "common". Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-33-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 32 +++----------------------------- 1 file changed, 3 insertions(+), 29 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q, return 0; } -/* - * If use_cumulative_perms is true, use cumulative_perms and - * cumulative_shared_perms for first element of the list. Otherwise just refresh - * all permissions. - */ -static int bdrv_check_perm_common(GSList *list, BlockReopenQueue *q, - bool use_cumulative_perms, - uint64_t cumulative_perms, - uint64_t cumulative_shared_perms, - Transaction *tran, Error **errp) +static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, + Transaction *tran, Error **errp) { int ret; + uint64_t cumulative_perms, cumulative_shared_perms; BlockDriverState *bs; - if (use_cumulative_perms) { - bs = list->data; - - ret = bdrv_node_check_perm(bs, q, cumulative_perms, - cumulative_shared_perms, - tran, errp); - if (ret < 0) { - return ret; - } - - list = list->next; - } - for ( ; list; list = list->next) { bs = list->data; @@ -XXX,XX +XXX,XX @@ static int bdrv_check_perm_common(GSList *list, BlockReopenQueue *q, return 0; } -static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, - Transaction *tran, Error **errp) -{ - return bdrv_check_perm_common(list, q, false, 0, 0, tran, errp); -} - static void bdrv_node_set_perm(BlockDriverState *bs) { BlockDriver *drv = bs->drv; -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> bdrv_replace_child() has only one caller, the second argument is unused. Inline it now. This triggers deletion of some more unused interfaces. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-34-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 101 ++++++++++---------------------------------------------- 1 file changed, 18 insertions(+), 83 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, return 0; } -static void bdrv_node_set_perm(BlockDriverState *bs) -{ - BlockDriver *drv = bs->drv; - BdrvChild *c; - - if (!drv) { - return; - } - - bdrv_drv_set_perm_commit(bs); - - /* Drivers that never have children can omit .bdrv_child_perm() */ - if (!drv->bdrv_child_perm) { - assert(QLIST_EMPTY(&bs->children)); - return; - } - - /* Update all children */ - QLIST_FOREACH(c, &bs->children, next) { - bdrv_child_set_perm_commit(c); - } -} - -static void bdrv_list_set_perm(GSList *list) -{ - for ( ; list; list = list->next) { - bdrv_node_set_perm((BlockDriverState *)list->data); - } -} - -static void bdrv_set_perm(BlockDriverState *bs) -{ - g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); - return bdrv_list_set_perm(list); -} - void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, uint64_t *shared_perm) { @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, } } -/* - * Updates @child to change its reference to point to @new_bs, including - * checking and applying the necessary permission updates both to the old node - * and to @new_bs. - * - * NULL is passed as @new_bs for removing the reference before freeing @child. - * - * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this - * function uses bdrv_set_perm() to update the permissions according to the new - * reference that @new_bs gets. - * - * Callers must ensure that child->frozen is false. - */ -static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) -{ - BlockDriverState *old_bs = child->bs; - - /* Asserts that child->frozen == false */ - bdrv_replace_child_noperm(child, new_bs); - - /* - * Start with the new node's permissions. If @new_bs is a (direct - * or indirect) child of @old_bs, we must complete the permission - * update on @new_bs before we loosen the restrictions on @old_bs. - * Otherwise, bdrv_check_perm() on @old_bs would re-initiate - * updating the permissions of @new_bs, and thus not purely loosen - * restrictions. - */ - if (new_bs) { - bdrv_set_perm(new_bs); - } - - if (old_bs) { - /* - * Update permissions for old node. We're just taking a parent away, so - * we're loosening restrictions. Errors of permission update are not - * fatal in this case, ignore them. - */ - bdrv_refresh_perms(old_bs, NULL); - - /* When the parent requiring a non-default AioContext is removed, the - * node moves back to the main AioContext */ - bdrv_try_set_aio_context(old_bs, qemu_get_aio_context(), NULL); - } -} - static void bdrv_child_free(void *opaque) { BdrvChild *c = opaque; @@ -XXX,XX +XXX,XX @@ static int bdrv_attach_child_noperm(BlockDriverState *parent_bs, static void bdrv_detach_child(BdrvChild *child) { - bdrv_replace_child(child, NULL); + BlockDriverState *old_bs = child->bs; + + bdrv_replace_child_noperm(child, NULL); bdrv_remove_empty_child(child); + + if (old_bs) { + /* + * Update permissions for old node. We're just taking a parent away, so + * we're loosening restrictions. Errors of permission update are not + * fatal in this case, ignore them. + */ + bdrv_refresh_perms(old_bs, NULL); + + /* + * When the parent requiring a non-default AioContext is removed, the + * node moves back to the main AioContext + */ + bdrv_try_set_aio_context(old_bs, qemu_get_aio_context(), NULL); + } } /* -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Old interfaces dropped, nobody directly calls bdrv_child_set_perm_abort() and bdrv_child_set_perm_commit(), so we can use personal state structure for the action and stop exploiting BdrvChild structure. Also, drop "_safe" suffix which is redundant now. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-35-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block_int.h | 5 ---- block.c | 63 ++++++++++++++------------------------- 2 files changed, 22 insertions(+), 46 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -XXX,XX +XXX,XX @@ struct BdrvChild { */ uint64_t shared_perm; - /* backup of permissions during permission update procedure */ - bool has_backup_perm; - uint64_t backup_perm; - uint64_t backup_shared_perm; - /* * This link is frozen: the child can neither be replaced nor * detached from the parent. diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static GSList *bdrv_topological_dfs(GSList *list, GHashTable *found, return g_slist_prepend(list, bs); } -static void bdrv_child_set_perm_commit(void *opaque) -{ - BdrvChild *c = opaque; - - c->has_backup_perm = false; -} +typedef struct BdrvChildSetPermState { + BdrvChild *child; + uint64_t old_perm; + uint64_t old_shared_perm; +} BdrvChildSetPermState; static void bdrv_child_set_perm_abort(void *opaque) { - BdrvChild *c = opaque; - /* - * We may have child->has_backup_perm unset at this point, as in case of - * _check_ stage of permission update failure we may _check_ not the whole - * subtree. Still, _abort_ is called on the whole subtree anyway. - */ - if (c->has_backup_perm) { - c->perm = c->backup_perm; - c->shared_perm = c->backup_shared_perm; - c->has_backup_perm = false; - } + BdrvChildSetPermState *s = opaque; + + s->child->perm = s->old_perm; + s->child->shared_perm = s->old_shared_perm; } static TransactionActionDrv bdrv_child_set_pem_drv = { .abort = bdrv_child_set_perm_abort, - .commit = bdrv_child_set_perm_commit, + .clean = g_free, }; -/* - * With tran=NULL needs to be followed by direct call to either - * bdrv_child_set_perm_commit() or bdrv_child_set_perm_abort(). - * - * With non-NULL tran needs to be followed by tran_abort() or tran_commit() - * instead. - */ -static void bdrv_child_set_perm_safe(BdrvChild *c, uint64_t perm, - uint64_t shared, Transaction *tran) +static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, + uint64_t shared, Transaction *tran) { - if (!c->has_backup_perm) { - c->has_backup_perm = true; - c->backup_perm = c->perm; - c->backup_shared_perm = c->shared_perm; - } - /* - * Note: it's OK if c->has_backup_perm was already set, as we can find the - * same c twice during check_perm procedure - */ + BdrvChildSetPermState *s = g_new(BdrvChildSetPermState, 1); + + *s = (BdrvChildSetPermState) { + .child = c, + .old_perm = c->perm, + .old_shared_perm = c->shared_perm, + }; c->perm = perm; c->shared_perm = shared; - if (tran) { - tran_add(tran, &bdrv_child_set_pem_drv, c); - } + tran_add(tran, &bdrv_child_set_pem_drv, s); } static void bdrv_drv_set_perm_commit(void *opaque) @@ -XXX,XX +XXX,XX @@ static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q, bdrv_child_perm(bs, c->bs, c, c->role, q, cumulative_perms, cumulative_shared_perms, &cur_perm, &cur_shared); - bdrv_child_set_perm_safe(c, cur_perm, cur_shared, tran); + bdrv_child_set_perm(c, cur_perm, cur_shared, tran); } return 0; @@ -XXX,XX +XXX,XX @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, Transaction *tran = tran_new(); int ret; - bdrv_child_set_perm_safe(c, perm, shared, tran); + bdrv_child_set_perm(c, perm, shared, tran); ret = bdrv_refresh_perms(c->bs, &local_err); -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> We don't have bdrv_replace_child(), so it's time for bdrv_replace_child_safe() to take its place. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-36-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static TransactionActionDrv bdrv_replace_child_drv = { }; /* - * bdrv_replace_child_safe + * bdrv_replace_child * * Note: real unref of old_bs is done only on commit. */ -static void bdrv_replace_child_safe(BdrvChild *child, BlockDriverState *new_bs, - Transaction *tran) +static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs, + Transaction *tran) { BdrvReplaceChildState *s = g_new(BdrvReplaceChildState, 1); *s = (BdrvReplaceChildState) { @@ -XXX,XX +XXX,XX @@ static void bdrv_remove_filter_or_cow_child(BlockDriverState *bs, } if (child->bs) { - bdrv_replace_child_safe(child, NULL, tran); + bdrv_replace_child(child, NULL, tran); } s = g_new(BdrvRemoveFilterOrCowChild, 1); @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_noperm(BlockDriverState *from, c->name, from->node_name); return -EPERM; } - bdrv_replace_child_safe(c, to, tran); + bdrv_replace_child(c, to, tran); } return 0; -- 2.30.2 From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Now, bdrv_node_check_perm() is called only with fresh cumulative permissions, so its actually "refresh_perm". Move permission calculation to the function. Also, drop unreachable error message and rewrite the remaining one to be more generic (as now we don't know which node is added and which was already here). Add also Virtuozzo copyright, as big work is done at this point. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-37-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 38 +++++++++++--------------------------- tests/qemu-iotests/245 | 2 +- 2 files changed, 12 insertions(+), 28 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ * QEMU System Emulator block driver * * Copyright (c) 2003 Fabrice Bellard + * Copyright (c) 2020 Virtuozzo International GmbH. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs, } /* - * Check whether permissions on this node can be changed in a way that - * @cumulative_perms and @cumulative_shared_perms are the new cumulative - * permissions of all its parents. This involves checking whether all necessary - * permission changes to child nodes can be performed. - * - * A call to this function must always be followed by a call to bdrv_set_perm() - * or bdrv_abort_perm_update(). + * Refresh permissions in @bs subtree. The function is intended to be called + * after some graph modification that was done without permission update. */ -static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q, - uint64_t cumulative_perms, - uint64_t cumulative_shared_perms, - Transaction *tran, Error **errp) +static int bdrv_node_refresh_perm(BlockDriverState *bs, BlockReopenQueue *q, + Transaction *tran, Error **errp) { BlockDriver *drv = bs->drv; BdrvChild *c; int ret; + uint64_t cumulative_perms, cumulative_shared_perms; + + bdrv_get_cumulative_perm(bs, &cumulative_perms, &cumulative_shared_perms); /* Write permissions never work with read-only images */ if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) && @@ -XXX,XX +XXX,XX @@ static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q, if (!bdrv_is_writable_after_reopen(bs, NULL)) { error_setg(errp, "Block node is read-only"); } else { - uint64_t current_perms, current_shared; - bdrv_get_cumulative_perm(bs, &current_perms, &current_shared); - if (current_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) { - error_setg(errp, "Cannot make block node read-only, there is " - "a writer on it"); - } else { - error_setg(errp, "Cannot make block node read-only and create " - "a writer on it"); - } + error_setg(errp, "Read-only block node '%s' cannot support " + "read-write users", bdrv_get_node_name(bs)); } return -EPERM; @@ -XXX,XX +XXX,XX @@ static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, Transaction *tran, Error **errp) { int ret; - uint64_t cumulative_perms, cumulative_shared_perms; BlockDriverState *bs; for ( ; list; list = list->next) { @@ -XXX,XX +XXX,XX @@ static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, return -EINVAL; } - bdrv_get_cumulative_perm(bs, &cumulative_perms, - &cumulative_shared_perms); - - ret = bdrv_node_check_perm(bs, q, cumulative_perms, - cumulative_shared_perms, - tran, errp); + ret = bdrv_node_refresh_perm(bs, q, tran, errp); if (ret < 0) { return ret; } diff --git a/tests/qemu-iotests/245 b/tests/qemu-iotests/245 index XXXXXXX..XXXXXXX 100755 --- a/tests/qemu-iotests/245 +++ b/tests/qemu-iotests/245 @@ -XXX,XX +XXX,XX @@ class TestBlockdevReopen(iotests.QMPTestCase): # We can't reopen hd1 to read-only, as block-stream requires it to be # read-write self.reopen(opts['backing'], {'read-only': True}, - "Cannot make block node read-only, there is a writer on it") + "Read-only block node 'hd1' cannot support read-write users") # We can't remove hd2 while the stream job is ongoing opts['backing']['backing'] = None -- 2.30.2 Normally, blk_new_open() just shares all permissions. This was fine originally when permissions only protected against uses in the same process because no other part of the code would actually get to access the block nodes opened with blk_new_open(). However, since we use it for file locking now, unsharing permissions becomes desirable. Add a new BDRV_O_NO_SHARE flag that is used in blk_new_open() to unshare any permissions that can be unshared. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210422164344.283389-2-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block.h | 1 + block/block-backend.c | 19 +++++++++++++------ 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -XXX,XX +XXX,XX @@ typedef struct HDGeometry { uint32_t cylinders; } HDGeometry; +#define BDRV_O_NO_SHARE 0x0001 /* don't share permissions */ #define BDRV_O_RDWR 0x0002 #define BDRV_O_RESIZE 0x0004 /* request permission for resizing the node */ #define BDRV_O_SNAPSHOT 0x0008 /* open the file read only and save writes in a snapshot */ diff --git a/block/block-backend.c b/block/block-backend.c index XXXXXXX..XXXXXXX 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -XXX,XX +XXX,XX @@ BlockBackend *blk_new_open(const char *filename, const char *reference, BlockBackend *blk; BlockDriverState *bs; uint64_t perm = 0; + uint64_t shared = BLK_PERM_ALL; - /* blk_new_open() is mainly used in .bdrv_create implementations and the - * tools where sharing isn't a concern because the BDS stays private, so we - * just request permission according to the flags. + /* + * blk_new_open() is mainly used in .bdrv_create implementations and the + * tools where sharing isn't a major concern because the BDS stays private + * and the file is generally not supposed to be used by a second process, + * so we just request permission according to the flags. * * The exceptions are xen_disk and blockdev_init(); in these cases, the * caller of blk_new_open() doesn't make use of the permissions, but they * shouldn't hurt either. We can still share everything here because the - * guest devices will add their own blockers if they can't share. */ + * guest devices will add their own blockers if they can't share. + */ if ((flags & BDRV_O_NO_IO) == 0) { perm |= BLK_PERM_CONSISTENT_READ; if (flags & BDRV_O_RDWR) { @@ -XXX,XX +XXX,XX @@ BlockBackend *blk_new_open(const char *filename, const char *reference, if (flags & BDRV_O_RESIZE) { perm |= BLK_PERM_RESIZE; } + if (flags & BDRV_O_NO_SHARE) { + shared = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED; + } - blk = blk_new(qemu_get_aio_context(), perm, BLK_PERM_ALL); + blk = blk_new(qemu_get_aio_context(), perm, shared); bs = bdrv_open(filename, reference, options, flags, errp); if (!bs) { blk_unref(blk); @@ -XXX,XX +XXX,XX @@ BlockBackend *blk_new_open(const char *filename, const char *reference, blk->root = bdrv_root_attach_child(bs, "root", &child_root, BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, - perm, BLK_PERM_ALL, blk, errp); + perm, shared, blk, errp); if (!blk->root) { blk_unref(blk); return NULL; -- 2.30.2 For a successful conversion of an image, we must make sure that its content doesn't change during the conversion. A special case of this is using the same image file both as the source and as the destination. If both input and output format are raw, the operation would just be useless work, with other formats it is a sure way to destroy the image. This will now fail because the image file can't be opened a second time for the output when opening it for the input has already acquired file locks to unshare BLK_PERM_WRITE. Nevertheless, if there is some reason in a special case why it is actually okay to allow writes to the image while it is being converted, -U can still be used to force sharing all permissions. Note that for most image formats, BLK_PERM_WRITE would already be unshared by the format driver, so this only really makes a difference for raw source images (but any output format). Reported-by: Xueqiang Wei <xuwei@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210422164344.283389-3-kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- qemu-img.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/qemu-img.c b/qemu-img.c index XXXXXXX..XXXXXXX 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -XXX,XX +XXX,XX @@ static void set_rate_limit(BlockBackend *blk, int64_t rate_limit) static int img_convert(int argc, char **argv) { - int c, bs_i, flags, src_flags = 0; + int c, bs_i, flags, src_flags = BDRV_O_NO_SHARE; const char *fmt = NULL, *out_fmt = NULL, *cache = "unsafe", *src_cache = BDRV_DEFAULT_CACHE, *out_baseimg = NULL, *out_filename, *out_baseimg_param, *snapshot_name = NULL; -- 2.30.2 virtio_add_queue() aborts when queue_size > VIRTQUEUE_MAX_SIZE, so vhost_user_blk_device_realize() should check this before calling it. Simple reproducer: qemu-system-x86_64 \ -chardev null,id=foo \ -device vhost-user-blk-pci,queue-size=4096,chardev=foo Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1935014 Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210413165654.50810-1-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- hw/block/vhost-user-blk.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c index XXXXXXX..XXXXXXX 100644 --- a/hw/block/vhost-user-blk.c +++ b/hw/block/vhost-user-blk.c @@ -XXX,XX +XXX,XX @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp) error_setg(errp, "vhost-user-blk: queue size must be non-zero"); return; } + if (s->queue_size > VIRTQUEUE_MAX_SIZE) { + error_setg(errp, "vhost-user-blk: queue size must not exceed %d", + VIRTQUEUE_MAX_SIZE); + return; + } if (!vhost_user_init(&s->vhost_user, &s->chardev, errp)) { return; -- 2.30.2 The following changes since commit 5204b499a6cae4dfd9fe762d5e6e82224892383b: mailmap: Fix Stefan Weil author email (2022-12-13 15:56:57 -0500) are available in the Git repository at: https://repo.or.cz/qemu/kevin.git tags/for-upstream for you to fetch changes up to 2ad19e5dc950d4b340894846b9e71c0b20f9a1cc: block: GRAPH_RDLOCK for functions only called by co_wrappers (2022-12-14 13:13:07 +0100) ---------------------------------------------------------------- Block layer patches - Code cleanups around block graph modification - Simplify drain - coroutine_fn correctness fixes, including splitting generated coroutine wrappers into co_wrapper (to be called only from non-coroutine context) and co_wrapper_mixed (both coroutine and non-coroutine context) - Introduce a block graph rwlock ---------------------------------------------------------------- Emanuele Giuseppe Esposito (21): block-io: introduce coroutine_fn duplicates for bdrv_common_block_status_above callers block-copy: add coroutine_fn annotations nbd/server.c: add coroutine_fn annotations block-backend: replace bdrv_*_above with blk_*_above block/vmdk: add coroutine_fn annotations block: avoid duplicating filename string in bdrv_create block: distinguish between bdrv_create running in coroutine and not block: bdrv_create_file is a coroutine_fn block: rename generated_co_wrapper in co_wrapper_mixed block-coroutine-wrapper.py: introduce co_wrapper block-coroutine-wrapper.py: support functions without bs arg block-coroutine-wrapper.py: support also basic return types block: convert bdrv_create to co_wrapper block/dirty-bitmap: convert coroutine-only functions to co_wrapper graph-lock: Implement guard macros async: Register/unregister aiocontext in graph lock list block: wrlock in bdrv_replace_child_noperm block: remove unnecessary assert_bdrv_graph_writable() block: assert that graph read and writes are performed correctly block-coroutine-wrapper.py: introduce annotations that take the graph rdlock block: use co_wrapper_mixed_bdrv_rdlock in functions taking the rdlock Kevin Wolf (25): qed: Don't yield in bdrv_qed_co_drain_begin() test-bdrv-drain: Don't yield in .bdrv_co_drained_begin/end() block: Revert .bdrv_drained_begin/end to non-coroutine_fn block: Remove drained_end_counter block: Inline bdrv_drain_invoke() block: Fix locking for bdrv_reopen_queue_child() block: Drain individual nodes during reopen block: Don't use subtree drains in bdrv_drop_intermediate() stream: Replace subtree drain with a single node drain block: Remove subtree drains block: Call drain callbacks only once block: Remove ignore_bds_parents parameter from drain_begin/end. block: Drop out of coroutine in bdrv_do_drained_begin_quiesce() block: Don't poll in bdrv_replace_child_noperm() block: Remove poll parameter from bdrv_parent_drained_begin_single() block: Factor out bdrv_drain_all_begin_nopoll() Import clang-tsa.h clang-tsa: Add TSA_ASSERT() macro clang-tsa: Add macros for shared locks configure: Enable -Wthread-safety if present test-bdrv-drain: Fix incorrrect drain assumptions block: Fix locking in external_snapshot_prepare() graph-lock: TSA annotations for lock/unlock functions Mark assert_bdrv_graph_readable/writable() GRAPH_RD/WRLOCK block: GRAPH_RDLOCK for functions only called by co_wrappers Paolo Bonzini (1): graph-lock: Introduce a lock to protect block graph operations Vladimir Sementsov-Ogievskiy (4): block: Inline bdrv_detach_child() block: drop bdrv_remove_filter_or_cow_child block: bdrv_refresh_perms(): allow external tran block: refactor bdrv_list_refresh_perms to allow any list of nodes docs/devel/block-coroutine-wrapper.rst | 6 +- configure | 1 + block/block-gen.h | 11 +- block/coroutines.h | 21 +- include/block/aio.h | 9 + include/block/block-common.h | 27 ++- include/block/block-copy.h | 5 +- include/block/block-global-state.h | 15 +- include/block/block-io.h | 136 +++++------ include/block/block_int-common.h | 49 ++-- include/block/block_int-global-state.h | 17 -- include/block/block_int-io.h | 12 - include/block/block_int.h | 1 + include/block/dirty-bitmap.h | 10 +- include/block/graph-lock.h | 280 +++++++++++++++++++++++ include/qemu/clang-tsa.h | 114 ++++++++++ include/sysemu/block-backend-io.h | 77 ++++--- block.c | 404 ++++++++++++++++++--------------- block/block-backend.c | 25 +- block/block-copy.c | 21 +- block/commit.c | 4 +- block/crypto.c | 2 +- block/dirty-bitmap.c | 88 +------ block/graph-lock.c | 275 ++++++++++++++++++++++ block/io.c | 367 ++++++++++-------------------- block/parallels.c | 2 +- block/qcow.c | 2 +- block/qcow2.c | 4 +- block/qed.c | 28 ++- block/raw-format.c | 2 +- block/replication.c | 6 - block/stream.c | 26 ++- block/throttle.c | 8 +- block/vdi.c | 2 +- block/vhdx.c | 2 +- block/vmdk.c | 38 ++-- block/vpc.c | 2 +- blockdev.c | 17 +- blockjob.c | 2 +- nbd/server.c | 47 ++-- stubs/graph-lock.c | 10 + tests/unit/test-bdrv-drain.c | 387 +++++++++---------------------- util/async.c | 4 + scripts/block-coroutine-wrapper.py | 133 ++++++++--- block/meson.build | 2 + stubs/meson.build | 1 + 46 files changed, 1575 insertions(+), 1127 deletions(-) create mode 100644 include/block/graph-lock.h create mode 100644 include/qemu/clang-tsa.h create mode 100644 block/graph-lock.c create mode 100644 stubs/graph-lock.c From: Vladimir Sementsov-Ogievskiy <vladimir.sementsov-ogievskiy@openvz.org> The only caller is bdrv_root_unref_child(), let's just do the logic directly in it. It simplifies further conversion of bdrv_root_unref_child() to transaction actions. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221107163558.618889-2-vsementsov@yandex-team.ru> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 46 +++++++++++++++++++--------------------------- 1 file changed, 19 insertions(+), 27 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static BdrvChild *bdrv_attach_child_noperm(BlockDriverState *parent_bs, tran, errp); } -static void bdrv_detach_child(BdrvChild *child) -{ - BlockDriverState *old_bs = child->bs; - - GLOBAL_STATE_CODE(); - bdrv_replace_child_noperm(child, NULL); - bdrv_child_free(child); - - if (old_bs) { - /* - * Update permissions for old node. We're just taking a parent away, so - * we're loosening restrictions. Errors of permission update are not - * fatal in this case, ignore them. - */ - bdrv_refresh_perms(old_bs, NULL); - - /* - * When the parent requiring a non-default AioContext is removed, the - * node moves back to the main AioContext - */ - bdrv_try_change_aio_context(old_bs, qemu_get_aio_context(), NULL, NULL); - } -} - /* * This function steals the reference to child_bs from the caller. * That reference is later dropped by bdrv_root_unref_child(). @@ -XXX,XX +XXX,XX @@ out: /* Callers must ensure that child->frozen is false. */ void bdrv_root_unref_child(BdrvChild *child) { - BlockDriverState *child_bs; + BlockDriverState *child_bs = child->bs; GLOBAL_STATE_CODE(); + bdrv_replace_child_noperm(child, NULL); + bdrv_child_free(child); + + if (child_bs) { + /* + * Update permissions for old node. We're just taking a parent away, so + * we're loosening restrictions. Errors of permission update are not + * fatal in this case, ignore them. + */ + bdrv_refresh_perms(child_bs, NULL); + + /* + * When the parent requiring a non-default AioContext is removed, the + * node moves back to the main AioContext + */ + bdrv_try_change_aio_context(child_bs, qemu_get_aio_context(), NULL, + NULL); + } - child_bs = child->bs; - bdrv_detach_child(child); bdrv_unref(child_bs); } -- 2.38.1 From: Vladimir Sementsov-Ogievskiy <vladimir.sementsov-ogievskiy@openvz.org> Drop this simple wrapper used only in one place. We have too many graph modifying functions even without it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221107163558.618889-3-vsementsov@yandex-team.ru> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static bool bdrv_recurse_has_child(BlockDriverState *bs, static void bdrv_replace_child_noperm(BdrvChild *child, BlockDriverState *new_bs); static void bdrv_remove_child(BdrvChild *child, Transaction *tran); -static void bdrv_remove_filter_or_cow_child(BlockDriverState *bs, - Transaction *tran); static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, @@ -XXX,XX +XXX,XX @@ static void bdrv_remove_child(BdrvChild *child, Transaction *tran) tran_add(tran, &bdrv_remove_child_drv, child); } -/* - * A function to remove backing-chain child of @bs if exists: cow child for - * format nodes (always .backing) and filter child for filters (may be .file or - * .backing) - */ -static void bdrv_remove_filter_or_cow_child(BlockDriverState *bs, - Transaction *tran) -{ - bdrv_remove_child(bdrv_filter_or_cow_child(bs), tran); -} - static int bdrv_replace_node_noperm(BlockDriverState *from, BlockDriverState *to, bool auto_skip, Transaction *tran, @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_common(BlockDriverState *from, } if (detach_subchain) { - bdrv_remove_filter_or_cow_child(to_cow_parent, tran); + bdrv_remove_child(bdrv_filter_or_cow_child(to_cow_parent), tran); } found = g_hash_table_new(NULL, NULL); -- 2.38.1 From: Vladimir Sementsov-Ogievskiy <vladimir.sementsov-ogievskiy@openvz.org> Allow passing external Transaction pointer, stop creating extra Transaction objects. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221107163558.618889-4-vsementsov@yandex-team.ru> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ char *bdrv_perm_names(uint64_t perm) } -static int bdrv_refresh_perms(BlockDriverState *bs, Error **errp) +/* @tran is allowed to be NULL. In this case no rollback is possible */ +static int bdrv_refresh_perms(BlockDriverState *bs, Transaction *tran, + Error **errp) { int ret; - Transaction *tran = tran_new(); + Transaction *local_tran = NULL; g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs); GLOBAL_STATE_CODE(); + if (!tran) { + tran = local_tran = tran_new(); + } + ret = bdrv_list_refresh_perms(list, NULL, tran, errp); - tran_finalize(tran, ret); + + if (local_tran) { + tran_finalize(local_tran, ret); + } return ret; } @@ -XXX,XX +XXX,XX @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, bdrv_child_set_perm(c, perm, shared, tran); - ret = bdrv_refresh_perms(c->bs, &local_err); + ret = bdrv_refresh_perms(c->bs, tran, &local_err); tran_finalize(tran, ret); @@ -XXX,XX +XXX,XX @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, goto out; } - ret = bdrv_refresh_perms(child_bs, errp); + ret = bdrv_refresh_perms(child_bs, tran, errp); out: tran_finalize(tran, ret); @@ -XXX,XX +XXX,XX @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, goto out; } - ret = bdrv_refresh_perms(parent_bs, errp); + ret = bdrv_refresh_perms(parent_bs, tran, errp); if (ret < 0) { goto out; } @@ -XXX,XX +XXX,XX @@ void bdrv_root_unref_child(BdrvChild *child) * we're loosening restrictions. Errors of permission update are not * fatal in this case, ignore them. */ - bdrv_refresh_perms(child_bs, NULL); + bdrv_refresh_perms(child_bs, NULL, NULL); /* * When the parent requiring a non-default AioContext is removed, the @@ -XXX,XX +XXX,XX @@ int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, goto out; } - ret = bdrv_refresh_perms(bs, errp); + ret = bdrv_refresh_perms(bs, tran, errp); out: tran_finalize(tran, ret); @@ -XXX,XX +XXX,XX @@ int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top, goto out; } - ret = bdrv_refresh_perms(bs_new, errp); + ret = bdrv_refresh_perms(bs_new, tran, errp); out: tran_finalize(tran, ret); @@ -XXX,XX +XXX,XX @@ int bdrv_activate(BlockDriverState *bs, Error **errp) */ if (bs->open_flags & BDRV_O_INACTIVE) { bs->open_flags &= ~BDRV_O_INACTIVE; - ret = bdrv_refresh_perms(bs, errp); + ret = bdrv_refresh_perms(bs, NULL, errp); if (ret < 0) { bs->open_flags |= BDRV_O_INACTIVE; return ret; @@ -XXX,XX +XXX,XX @@ static int bdrv_inactivate_recurse(BlockDriverState *bs) * We only tried to loosen restrictions, so errors are not fatal, ignore * them. */ - bdrv_refresh_perms(bs, NULL); + bdrv_refresh_perms(bs, NULL, NULL); /* Recursively inactivate children */ QLIST_FOREACH(child, &bs->children, next) { -- 2.38.1 From: Vladimir Sementsov-Ogievskiy <vladimir.sementsov-ogievskiy@openvz.org> We are going to increase usage of collecting nodes in a list to then update, and calling bdrv_topological_dfs() each time is not convenient, and not correct as we are going to interleave graph modifying with filling the node list. So, let's switch to a function that takes any list of nodes, adds all their subtrees and do topological sort. And finally, refresh permissions. While being here, make the function public, as we'll want to use it from blockdev.c in near future. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221107163558.618889-5-vsementsov@yandex-team.ru> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 51 ++++++++++++++++++++++++++++++++------------------- 1 file changed, 32 insertions(+), 19 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_node_refresh_perm(BlockDriverState *bs, BlockReopenQueue *q, return 0; } -static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, - Transaction *tran, Error **errp) +/* + * @list is a product of bdrv_topological_dfs() (may be called several times) - + * a topologically sorted subgraph. + */ +static int bdrv_do_refresh_perms(GSList *list, BlockReopenQueue *q, + Transaction *tran, Error **errp) { int ret; BlockDriverState *bs; @@ -XXX,XX +XXX,XX @@ static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, return 0; } +/* + * @list is any list of nodes. List is completed by all subtrees and + * topologically sorted. It's not a problem if some node occurs in the @list + * several times. + */ +static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q, + Transaction *tran, Error **errp) +{ + g_autoptr(GHashTable) found = g_hash_table_new(NULL, NULL); + g_autoptr(GSList) refresh_list = NULL; + + for ( ; list; list = list->next) { + refresh_list = bdrv_topological_dfs(refresh_list, found, list->data); + } + + return bdrv_do_refresh_perms(refresh_list, q, tran, errp); +} + void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, uint64_t *shared_perm) { @@ -XXX,XX +XXX,XX @@ static int bdrv_refresh_perms(BlockDriverState *bs, Transaction *tran, tran = local_tran = tran_new(); } - ret = bdrv_list_refresh_perms(list, NULL, tran, errp); + ret = bdrv_do_refresh_perms(list, NULL, tran, errp); if (local_tran) { tran_finalize(local_tran, ret); @@ -XXX,XX +XXX,XX @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) BlockReopenQueueEntry *bs_entry, *next; AioContext *ctx; Transaction *tran = tran_new(); - g_autoptr(GHashTable) found = NULL; g_autoptr(GSList) refresh_list = NULL; assert(qemu_get_current_aio_context() == qemu_get_aio_context()); @@ -XXX,XX +XXX,XX @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) bs_entry->prepared = true; } - found = g_hash_table_new(NULL, NULL); QTAILQ_FOREACH(bs_entry, bs_queue, entry) { BDRVReopenState *state = &bs_entry->state; - refresh_list = bdrv_topological_dfs(refresh_list, found, state->bs); + refresh_list = g_slist_prepend(refresh_list, state->bs); if (state->old_backing_bs) { - refresh_list = bdrv_topological_dfs(refresh_list, found, - state->old_backing_bs); + refresh_list = g_slist_prepend(refresh_list, state->old_backing_bs); } if (state->old_file_bs) { - refresh_list = bdrv_topological_dfs(refresh_list, found, - state->old_file_bs); + refresh_list = g_slist_prepend(refresh_list, state->old_file_bs); } } @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_common(BlockDriverState *from, Error **errp) { Transaction *tran = tran_new(); - g_autoptr(GHashTable) found = NULL; g_autoptr(GSList) refresh_list = NULL; BlockDriverState *to_cow_parent = NULL; int ret; @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_common(BlockDriverState *from, bdrv_remove_child(bdrv_filter_or_cow_child(to_cow_parent), tran); } - found = g_hash_table_new(NULL, NULL); - - refresh_list = bdrv_topological_dfs(refresh_list, found, to); - refresh_list = bdrv_topological_dfs(refresh_list, found, from); + refresh_list = g_slist_prepend(refresh_list, to); + refresh_list = g_slist_prepend(refresh_list, from); ret = bdrv_list_refresh_perms(refresh_list, NULL, tran, errp); if (ret < 0) { @@ -XXX,XX +XXX,XX @@ int bdrv_replace_child_bs(BdrvChild *child, BlockDriverState *new_bs, { int ret; Transaction *tran = tran_new(); - g_autoptr(GHashTable) found = NULL; g_autoptr(GSList) refresh_list = NULL; BlockDriverState *old_bs = child->bs; @@ -XXX,XX +XXX,XX @@ int bdrv_replace_child_bs(BdrvChild *child, BlockDriverState *new_bs, bdrv_replace_child_tran(child, new_bs, tran); - found = g_hash_table_new(NULL, NULL); - refresh_list = bdrv_topological_dfs(refresh_list, found, old_bs); - refresh_list = bdrv_topological_dfs(refresh_list, found, new_bs); + refresh_list = g_slist_prepend(refresh_list, old_bs); + refresh_list = g_slist_prepend(refresh_list, new_bs); ret = bdrv_list_refresh_perms(refresh_list, NULL, tran, errp); -- 2.38.1 We want to change .bdrv_co_drained_begin() back to be a non-coroutine callback, so in preparation, avoid yielding in its implementation. Because we increase bs->in_flight and bdrv_drained_begin() polls, the behaviour is unchanged. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221118174110.55183-2-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/qed.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/block/qed.c b/block/qed.c index XXXXXXX..XXXXXXX 100644 --- a/block/qed.c +++ b/block/qed.c @@ -XXX,XX +XXX,XX @@ static void coroutine_fn qed_unplug_allocating_write_reqs(BDRVQEDState *s) qemu_co_mutex_unlock(&s->table_lock); } -static void coroutine_fn qed_need_check_timer_entry(void *opaque) +static void coroutine_fn qed_need_check_timer(BDRVQEDState *s) { - BDRVQEDState *s = opaque; int ret; trace_qed_need_check_timer_cb(s); @@ -XXX,XX +XXX,XX @@ static void coroutine_fn qed_need_check_timer_entry(void *opaque) (void) ret; } +static void coroutine_fn qed_need_check_timer_entry(void *opaque) +{ + BDRVQEDState *s = opaque; + + qed_need_check_timer(opaque); + bdrv_dec_in_flight(s->bs); +} + static void qed_need_check_timer_cb(void *opaque) { + BDRVQEDState *s = opaque; Coroutine *co = qemu_coroutine_create(qed_need_check_timer_entry, opaque); + + bdrv_inc_in_flight(s->bs); qemu_coroutine_enter(co); } @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_qed_co_drain_begin(BlockDriverState *bs) * header is flushed. */ if (s->need_check_timer && timer_pending(s->need_check_timer)) { + Coroutine *co; + qed_cancel_need_check_timer(s); - qed_need_check_timer_entry(s); + co = qemu_coroutine_create(qed_need_check_timer_entry, s); + bdrv_inc_in_flight(bs); + aio_co_enter(bdrv_get_aio_context(bs), co); } } -- 2.38.1 We want to change .bdrv_co_drained_begin/end() back to be non-coroutine callbacks, so in preparation, avoid yielding in their implementation. This does almost the same as the existing logic in bdrv_drain_invoke(), by creating and entering coroutines internally. However, since the test case is by far the heaviest user of coroutine code in drain callbacks, it is preferable to have the complexity in the test case rather than the drain core, which is already complicated enough without this. The behaviour for bdrv_drain_begin() is unchanged because we increase bs->in_flight and this is still polled. However, bdrv_drain_end() doesn't wait for the spawned coroutine to complete any more. This is fine, we don't rely on bdrv_drain_end() restarting all operations immediately before the next aio_poll(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221118174110.55183-3-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- tests/unit/test-bdrv-drain.c | 64 ++++++++++++++++++++++++++---------- 1 file changed, 46 insertions(+), 18 deletions(-) diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-drain.c +++ b/tests/unit/test-bdrv-drain.c @@ -XXX,XX +XXX,XX @@ typedef struct BDRVTestState { bool sleep_in_drain_begin; } BDRVTestState; +static void coroutine_fn sleep_in_drain_begin(void *opaque) +{ + BlockDriverState *bs = opaque; + + qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000); + bdrv_dec_in_flight(bs); +} + static void coroutine_fn bdrv_test_co_drain_begin(BlockDriverState *bs) { BDRVTestState *s = bs->opaque; s->drain_count++; if (s->sleep_in_drain_begin) { - qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000); + Coroutine *co = qemu_coroutine_create(sleep_in_drain_begin, bs); + bdrv_inc_in_flight(bs); + aio_co_enter(bdrv_get_aio_context(bs), co); } } @@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_replace_test_co_preadv(BlockDriverState *bs, return 0; } +static void coroutine_fn bdrv_replace_test_drain_co(void *opaque) +{ + BlockDriverState *bs = opaque; + BDRVReplaceTestState *s = bs->opaque; + + /* Keep waking io_co up until it is done */ + while (s->io_co) { + aio_co_wake(s->io_co); + s->io_co = NULL; + qemu_coroutine_yield(); + } + s->drain_co = NULL; + bdrv_dec_in_flight(bs); +} + /** * If .drain_count is 0, wake up .io_co if there is one; and set * .was_drained. @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_replace_test_co_drain_begin(BlockDriverState *bs) BDRVReplaceTestState *s = bs->opaque; if (!s->drain_count) { - /* Keep waking io_co up until it is done */ - s->drain_co = qemu_coroutine_self(); - while (s->io_co) { - aio_co_wake(s->io_co); - s->io_co = NULL; - qemu_coroutine_yield(); - } - s->drain_co = NULL; - + s->drain_co = qemu_coroutine_create(bdrv_replace_test_drain_co, bs); + bdrv_inc_in_flight(bs); + aio_co_enter(bdrv_get_aio_context(bs), s->drain_co); s->was_drained = true; } s->drain_count++; } +static void coroutine_fn bdrv_replace_test_read_entry(void *opaque) +{ + BlockDriverState *bs = opaque; + char data; + QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, &data, 1); + int ret; + + /* Queue a read request post-drain */ + ret = bdrv_replace_test_co_preadv(bs, 0, 1, &qiov, 0); + g_assert(ret >= 0); + bdrv_dec_in_flight(bs); +} + /** * Reduce .drain_count, set .was_undrained once it reaches 0. * If .drain_count reaches 0 and the node has a backing file, issue a @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_replace_test_co_drain_end(BlockDriverState *bs) g_assert(s->drain_count > 0); if (!--s->drain_count) { - int ret; - s->was_undrained = true; if (bs->backing) { - char data; - QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, &data, 1); - - /* Queue a read request post-drain */ - ret = bdrv_replace_test_co_preadv(bs, 0, 1, &qiov, 0); - g_assert(ret >= 0); + Coroutine *co = qemu_coroutine_create(bdrv_replace_test_read_entry, + bs); + bdrv_inc_in_flight(bs); + aio_co_enter(bdrv_get_aio_context(bs), co); } } } -- 2.38.1 Polling during bdrv_drained_end() can be problematic (and in the future, we may get cases for bdrv_drained_begin() where polling is forbidden, and we don't care about already in-flight requests, but just want to prevent new requests from arriving). The .bdrv_drained_begin/end callbacks running in a coroutine is the only reason why we have to do this polling, so make them non-coroutine callbacks again. None of the callers actually yield any more. This means that bdrv_drained_end() effectively doesn't poll any more, even if AIO_WAIT_WHILE() loops are still there (their condition is false from the beginning). This is generally not a problem, but in test-bdrv-drain, some additional explicit aio_poll() calls need to be added because the test case wants to verify the final state after BHs have executed. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221118174110.55183-4-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block_int-common.h | 10 ++++--- block.c | 4 +-- block/io.c | 49 +++++--------------------------- block/qed.c | 6 ++-- block/throttle.c | 8 +++--- tests/unit/test-bdrv-drain.c | 18 ++++++------ 6 files changed, 32 insertions(+), 63 deletions(-) diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -XXX,XX +XXX,XX @@ struct BlockDriver { void (*bdrv_io_unplug)(BlockDriverState *bs); /** - * bdrv_co_drain_begin is called if implemented in the beginning of a + * bdrv_drain_begin is called if implemented in the beginning of a * drain operation to drain and stop any internal sources of requests in * the driver. - * bdrv_co_drain_end is called if implemented at the end of the drain. + * bdrv_drain_end is called if implemented at the end of the drain. * * They should be used by the driver to e.g. manage scheduled I/O * requests, or toggle an internal state. After the end of the drain new * requests will continue normally. + * + * Implementations of both functions must not call aio_poll(). */ - void coroutine_fn (*bdrv_co_drain_begin)(BlockDriverState *bs); - void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs); + void (*bdrv_drain_begin)(BlockDriverState *bs); + void (*bdrv_drain_end)(BlockDriverState *bs); bool (*bdrv_supports_persistent_dirty_bitmap)(BlockDriverState *bs); bool coroutine_fn (*bdrv_co_can_store_new_dirty_bitmap)( diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv, assert(is_power_of_2(bs->bl.request_alignment)); for (i = 0; i < bs->quiesce_counter; i++) { - if (drv->bdrv_co_drain_begin) { - drv->bdrv_co_drain_begin(bs); + if (drv->bdrv_drain_begin) { + drv->bdrv_drain_begin(bs); } } diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ typedef struct { int *drained_end_counter; } BdrvCoDrainData; -static void coroutine_fn bdrv_drain_invoke_entry(void *opaque) -{ - BdrvCoDrainData *data = opaque; - BlockDriverState *bs = data->bs; - - if (data->begin) { - bs->drv->bdrv_co_drain_begin(bs); - } else { - bs->drv->bdrv_co_drain_end(bs); - } - - /* Set data->done and decrement drained_end_counter before bdrv_wakeup() */ - qatomic_mb_set(&data->done, true); - if (!data->begin) { - qatomic_dec(data->drained_end_counter); - } - bdrv_dec_in_flight(bs); - - g_free(data); -} - -/* Recursively call BlockDriver.bdrv_co_drain_begin/end callbacks */ +/* Recursively call BlockDriver.bdrv_drain_begin/end callbacks */ static void bdrv_drain_invoke(BlockDriverState *bs, bool begin, int *drained_end_counter) { - BdrvCoDrainData *data; - - if (!bs->drv || (begin && !bs->drv->bdrv_co_drain_begin) || - (!begin && !bs->drv->bdrv_co_drain_end)) { + if (!bs->drv || (begin && !bs->drv->bdrv_drain_begin) || + (!begin && !bs->drv->bdrv_drain_end)) { return; } - data = g_new(BdrvCoDrainData, 1); - *data = (BdrvCoDrainData) { - .bs = bs, - .done = false, - .begin = begin, - .drained_end_counter = drained_end_counter, - }; - - if (!begin) { - qatomic_inc(drained_end_counter); + if (begin) { + bs->drv->bdrv_drain_begin(bs); + } else { + bs->drv->bdrv_drain_end(bs); } - - /* Make sure the driver callback completes during the polling phase for - * drain_begin. */ - bdrv_inc_in_flight(bs); - data->co = qemu_coroutine_create(bdrv_drain_invoke_entry, data); - aio_co_schedule(bdrv_get_aio_context(bs), data->co); } /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */ diff --git a/block/qed.c b/block/qed.c index XXXXXXX..XXXXXXX 100644 --- a/block/qed.c +++ b/block/qed.c @@ -XXX,XX +XXX,XX @@ static bool coroutine_fn qed_plug_allocating_write_reqs(BDRVQEDState *s) assert(!s->allocating_write_reqs_plugged); if (s->allocating_acb != NULL) { /* Another allocating write came concurrently. This cannot happen - * from bdrv_qed_co_drain_begin, but it can happen when the timer runs. + * from bdrv_qed_drain_begin, but it can happen when the timer runs. */ qemu_co_mutex_unlock(&s->table_lock); return false; @@ -XXX,XX +XXX,XX @@ static void bdrv_qed_attach_aio_context(BlockDriverState *bs, } } -static void coroutine_fn bdrv_qed_co_drain_begin(BlockDriverState *bs) +static void bdrv_qed_drain_begin(BlockDriverState *bs) { BDRVQEDState *s = bs->opaque; @@ -XXX,XX +XXX,XX @@ static BlockDriver bdrv_qed = { .bdrv_co_check = bdrv_qed_co_check, .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, - .bdrv_co_drain_begin = bdrv_qed_co_drain_begin, + .bdrv_drain_begin = bdrv_qed_drain_begin, }; static void bdrv_qed_init(void) diff --git a/block/throttle.c b/block/throttle.c index XXXXXXX..XXXXXXX 100644 --- a/block/throttle.c +++ b/block/throttle.c @@ -XXX,XX +XXX,XX @@ static void throttle_reopen_abort(BDRVReopenState *reopen_state) reopen_state->opaque = NULL; } -static void coroutine_fn throttle_co_drain_begin(BlockDriverState *bs) +static void throttle_drain_begin(BlockDriverState *bs) { ThrottleGroupMember *tgm = bs->opaque; if (qatomic_fetch_inc(&tgm->io_limits_disabled) == 0) { @@ -XXX,XX +XXX,XX @@ static void coroutine_fn throttle_co_drain_begin(BlockDriverState *bs) } } -static void coroutine_fn throttle_co_drain_end(BlockDriverState *bs) +static void throttle_drain_end(BlockDriverState *bs) { ThrottleGroupMember *tgm = bs->opaque; assert(tgm->io_limits_disabled); @@ -XXX,XX +XXX,XX @@ static BlockDriver bdrv_throttle = { .bdrv_reopen_commit = throttle_reopen_commit, .bdrv_reopen_abort = throttle_reopen_abort, - .bdrv_co_drain_begin = throttle_co_drain_begin, - .bdrv_co_drain_end = throttle_co_drain_end, + .bdrv_drain_begin = throttle_drain_begin, + .bdrv_drain_end = throttle_drain_end, .is_filter = true, .strong_runtime_opts = throttle_strong_runtime_opts, diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-drain.c +++ b/tests/unit/test-bdrv-drain.c @@ -XXX,XX +XXX,XX @@ static void coroutine_fn sleep_in_drain_begin(void *opaque) bdrv_dec_in_flight(bs); } -static void coroutine_fn bdrv_test_co_drain_begin(BlockDriverState *bs) +static void bdrv_test_drain_begin(BlockDriverState *bs) { BDRVTestState *s = bs->opaque; s->drain_count++; @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_test_co_drain_begin(BlockDriverState *bs) } } -static void coroutine_fn bdrv_test_co_drain_end(BlockDriverState *bs) +static void bdrv_test_drain_end(BlockDriverState *bs) { BDRVTestState *s = bs->opaque; s->drain_count--; @@ -XXX,XX +XXX,XX @@ static BlockDriver bdrv_test = { .bdrv_close = bdrv_test_close, .bdrv_co_preadv = bdrv_test_co_preadv, - .bdrv_co_drain_begin = bdrv_test_co_drain_begin, - .bdrv_co_drain_end = bdrv_test_co_drain_end, + .bdrv_drain_begin = bdrv_test_drain_begin, + .bdrv_drain_end = bdrv_test_drain_end, .bdrv_child_perm = bdrv_default_perms, @@ -XXX,XX +XXX,XX @@ static void test_blockjob_commit_by_drained_end(void) bdrv_drained_begin(bs_child); g_assert(!job_has_completed); bdrv_drained_end(bs_child); + aio_poll(qemu_get_aio_context(), false); g_assert(job_has_completed); bdrv_unref(bs_parents[0]); @@ -XXX,XX +XXX,XX @@ static void test_drop_intermediate_poll(void) g_assert(!job_has_completed); ret = bdrv_drop_intermediate(chain[1], chain[0], NULL); + aio_poll(qemu_get_aio_context(), false); g_assert(ret == 0); g_assert(job_has_completed); @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_replace_test_drain_co(void *opaque) * .was_drained. * Increment .drain_count. */ -static void coroutine_fn bdrv_replace_test_co_drain_begin(BlockDriverState *bs) +static void bdrv_replace_test_drain_begin(BlockDriverState *bs) { BDRVReplaceTestState *s = bs->opaque; @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_replace_test_read_entry(void *opaque) * If .drain_count reaches 0 and the node has a backing file, issue a * read request. */ -static void coroutine_fn bdrv_replace_test_co_drain_end(BlockDriverState *bs) +static void bdrv_replace_test_drain_end(BlockDriverState *bs) { BDRVReplaceTestState *s = bs->opaque; @@ -XXX,XX +XXX,XX @@ static BlockDriver bdrv_replace_test = { .bdrv_close = bdrv_replace_test_close, .bdrv_co_preadv = bdrv_replace_test_co_preadv, - .bdrv_co_drain_begin = bdrv_replace_test_co_drain_begin, - .bdrv_co_drain_end = bdrv_replace_test_co_drain_end, + .bdrv_drain_begin = bdrv_replace_test_drain_begin, + .bdrv_drain_end = bdrv_replace_test_drain_end, .bdrv_child_perm = bdrv_default_perms, }; -- 2.38.1 drained_end_counter is unused now, nobody changes its value any more. It can be removed. In cases where we had two almost identical functions that only differed in whether the caller passes drained_end_counter, or whether they would poll for a local drained_end_counter to reach 0, these become a single function. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20221118174110.55183-5-kwolf@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-io.h | 24 -------- include/block/block_int-common.h | 6 +- block.c | 5 +- block/block-backend.c | 4 +- block/io.c | 98 ++++++++------------------------ blockjob.c | 2 +- 6 files changed, 30 insertions(+), 109 deletions(-) diff --git a/include/block/block-io.h b/include/block/block-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset, int64_t bytes, BdrvRequestFlags read_flags, BdrvRequestFlags write_flags); -/** - * bdrv_drained_end_no_poll: - * - * Same as bdrv_drained_end(), but do not poll for the subgraph to - * actually become unquiesced. Therefore, no graph changes will occur - * with this function. - * - * *drained_end_counter is incremented for every background operation - * that is scheduled, and will be decremented for every operation once - * it settles. The caller must poll until it reaches 0. The counter - * should be accessed using atomic operations only. - */ -void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter); - - /* * "I/O or GS" API functions. These functions can run without * the BQL, but only in one specific iothread/main loop. @@ -XXX,XX +XXX,XX @@ void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll); * bdrv_parent_drained_end_single: * * End a quiesced section for the parent of @c. - * - * This polls @bs's AioContext until all scheduled sub-drained_ends - * have settled, which may result in graph changes. */ void bdrv_parent_drained_end_single(BdrvChild *c); @@ -XXX,XX +XXX,XX @@ void bdrv_subtree_drained_begin(BlockDriverState *bs); * bdrv_drained_end: * * End a quiescent section started by bdrv_drained_begin(). - * - * This polls @bs's AioContext until all scheduled sub-drained_ends - * have settled. On one hand, that may result in graph changes. On - * the other, this requires that the caller either runs in the main - * loop; or that all involved nodes (@bs and all of its parents) are - * in the caller's AioContext. */ void bdrv_drained_end(BlockDriverState *bs); diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -XXX,XX +XXX,XX @@ struct BdrvChildClass { * These functions must not change the graph (and therefore also must not * call aio_poll(), which could change the graph indirectly). * - * If drained_end() schedules background operations, it must atomically - * increment *drained_end_counter for each such operation and atomically - * decrement it once the operation has settled. - * * Note that this can be nested. If drained_begin() was called twice, new * I/O is allowed only after drained_end() was called twice, too. */ void (*drained_begin)(BdrvChild *child); - void (*drained_end)(BdrvChild *child, int *drained_end_counter); + void (*drained_end)(BdrvChild *child); /* * Returns whether the parent has pending requests for the child. This diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static bool bdrv_child_cb_drained_poll(BdrvChild *child) return bdrv_drain_poll(bs, false, NULL, false); } -static void bdrv_child_cb_drained_end(BdrvChild *child, - int *drained_end_counter) +static void bdrv_child_cb_drained_end(BdrvChild *child) { BlockDriverState *bs = child->opaque; - bdrv_drained_end_no_poll(bs, drained_end_counter); + bdrv_drained_end(bs); } static int bdrv_child_cb_inactivate(BdrvChild *child) diff --git a/block/block-backend.c b/block/block-backend.c index XXXXXXX..XXXXXXX 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -XXX,XX +XXX,XX @@ static void blk_root_inherit_options(BdrvChildRole role, bool parent_is_format, } static void blk_root_drained_begin(BdrvChild *child); static bool blk_root_drained_poll(BdrvChild *child); -static void blk_root_drained_end(BdrvChild *child, int *drained_end_counter); +static void blk_root_drained_end(BdrvChild *child); static void blk_root_change_media(BdrvChild *child, bool load); static void blk_root_resize(BdrvChild *child); @@ -XXX,XX +XXX,XX @@ static bool blk_root_drained_poll(BdrvChild *child) return busy || !!blk->in_flight; } -static void blk_root_drained_end(BdrvChild *child, int *drained_end_counter) +static void blk_root_drained_end(BdrvChild *child) { BlockBackend *blk = child->opaque; assert(blk->quiesce_counter); diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore, } } -static void bdrv_parent_drained_end_single_no_poll(BdrvChild *c, - int *drained_end_counter) +void bdrv_parent_drained_end_single(BdrvChild *c) { + IO_OR_GS_CODE(); + assert(c->parent_quiesce_counter > 0); c->parent_quiesce_counter--; if (c->klass->drained_end) { - c->klass->drained_end(c, drained_end_counter); + c->klass->drained_end(c); } } -void bdrv_parent_drained_end_single(BdrvChild *c) -{ - int drained_end_counter = 0; - AioContext *ctx = bdrv_child_get_parent_aio_context(c); - IO_OR_GS_CODE(); - bdrv_parent_drained_end_single_no_poll(c, &drained_end_counter); - AIO_WAIT_WHILE(ctx, qatomic_read(&drained_end_counter) > 0); -} - static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore, - bool ignore_bds_parents, - int *drained_end_counter) + bool ignore_bds_parents) { BdrvChild *c; @@ -XXX,XX +XXX,XX @@ static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore, if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) { continue; } - bdrv_parent_drained_end_single_no_poll(c, drained_end_counter); + bdrv_parent_drained_end_single(c); } } @@ -XXX,XX +XXX,XX @@ typedef struct { bool poll; BdrvChild *parent; bool ignore_bds_parents; - int *drained_end_counter; } BdrvCoDrainData; /* Recursively call BlockDriver.bdrv_drain_begin/end callbacks */ -static void bdrv_drain_invoke(BlockDriverState *bs, bool begin, - int *drained_end_counter) +static void bdrv_drain_invoke(BlockDriverState *bs, bool begin) { if (!bs->drv || (begin && !bs->drv->bdrv_drain_begin) || (!begin && !bs->drv->bdrv_drain_end)) { @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive, BdrvChild *parent, bool ignore_bds_parents, bool poll); static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive, - BdrvChild *parent, bool ignore_bds_parents, - int *drained_end_counter); + BdrvChild *parent, bool ignore_bds_parents); static void bdrv_co_drain_bh_cb(void *opaque) { @@ -XXX,XX +XXX,XX @@ static void bdrv_co_drain_bh_cb(void *opaque) aio_context_acquire(ctx); bdrv_dec_in_flight(bs); if (data->begin) { - assert(!data->drained_end_counter); bdrv_do_drained_begin(bs, data->recursive, data->parent, data->ignore_bds_parents, data->poll); } else { assert(!data->poll); bdrv_do_drained_end(bs, data->recursive, data->parent, - data->ignore_bds_parents, - data->drained_end_counter); + data->ignore_bds_parents); } aio_context_release(ctx); } else { @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, bool begin, bool recursive, BdrvChild *parent, bool ignore_bds_parents, - bool poll, - int *drained_end_counter) + bool poll) { BdrvCoDrainData data; Coroutine *self = qemu_coroutine_self(); @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, .parent = parent, .ignore_bds_parents = ignore_bds_parents, .poll = poll, - .drained_end_counter = drained_end_counter, }; if (bs) { @@ -XXX,XX +XXX,XX @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, } bdrv_parent_drained_begin(bs, parent, ignore_bds_parents); - bdrv_drain_invoke(bs, true, NULL); + bdrv_drain_invoke(bs, true); } static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive, @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive, if (qemu_in_coroutine()) { bdrv_co_yield_to_drain(bs, true, recursive, parent, ignore_bds_parents, - poll, NULL); + poll); return; } @@ -XXX,XX +XXX,XX @@ void bdrv_subtree_drained_begin(BlockDriverState *bs) /** * This function does not poll, nor must any of its recursively called - * functions. The *drained_end_counter pointee will be incremented - * once for every background operation scheduled, and decremented once - * the operation settles. Therefore, the pointer must remain valid - * until the pointee reaches 0. That implies that whoever sets up the - * pointee has to poll until it is 0. - * - * We use atomic operations to access *drained_end_counter, because - * (1) when called from bdrv_set_aio_context_ignore(), the subgraph of - * @bs may contain nodes in different AioContexts, - * (2) bdrv_drain_all_end() uses the same counter for all nodes, - * regardless of which AioContext they are in. + * functions. */ static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive, - BdrvChild *parent, bool ignore_bds_parents, - int *drained_end_counter) + BdrvChild *parent, bool ignore_bds_parents) { BdrvChild *child; int old_quiesce_counter; - assert(drained_end_counter != NULL); - if (qemu_in_coroutine()) { bdrv_co_yield_to_drain(bs, false, recursive, parent, ignore_bds_parents, - false, drained_end_counter); + false); return; } assert(bs->quiesce_counter > 0); /* Re-enable things in child-to-parent order */ - bdrv_drain_invoke(bs, false, drained_end_counter); - bdrv_parent_drained_end(bs, parent, ignore_bds_parents, - drained_end_counter); + bdrv_drain_invoke(bs, false); + bdrv_parent_drained_end(bs, parent, ignore_bds_parents); old_quiesce_counter = qatomic_fetch_dec(&bs->quiesce_counter); if (old_quiesce_counter == 1) { @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive, assert(!ignore_bds_parents); bs->recursive_quiesce_counter--; QLIST_FOREACH(child, &bs->children, next) { - bdrv_do_drained_end(child->bs, true, child, ignore_bds_parents, - drained_end_counter); + bdrv_do_drained_end(child->bs, true, child, ignore_bds_parents); } } } void bdrv_drained_end(BlockDriverState *bs) { - int drained_end_counter = 0; IO_OR_GS_CODE(); - bdrv_do_drained_end(bs, false, NULL, false, &drained_end_counter); - BDRV_POLL_WHILE(bs, qatomic_read(&drained_end_counter) > 0); -} - -void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter) -{ - IO_CODE(); - bdrv_do_drained_end(bs, false, NULL, false, drained_end_counter); + bdrv_do_drained_end(bs, false, NULL, false); } void bdrv_subtree_drained_end(BlockDriverState *bs) { - int drained_end_counter = 0; IO_OR_GS_CODE(); - bdrv_do_drained_end(bs, true, NULL, false, &drained_end_counter); - BDRV_POLL_WHILE(bs, qatomic_read(&drained_end_counter) > 0); + bdrv_do_drained_end(bs, true, NULL, false); } void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent) @@ -XXX,XX +XXX,XX @@ void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent) void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent) { - int drained_end_counter = 0; int i; IO_OR_GS_CODE(); for (i = 0; i < old_parent->recursive_quiesce_counter; i++) { - bdrv_do_drained_end(child->bs, true, child, false, - &drained_end_counter); + bdrv_do_drained_end(child->bs, true, child, false); } - - BDRV_POLL_WHILE(child->bs, qatomic_read(&drained_end_counter) > 0); } void bdrv_drain(BlockDriverState *bs) @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_begin(void) GLOBAL_STATE_CODE(); if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(NULL, true, false, NULL, true, true, NULL); + bdrv_co_yield_to_drain(NULL, true, false, NULL, true, true); return; } @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_begin(void) void bdrv_drain_all_end_quiesce(BlockDriverState *bs) { - int drained_end_counter = 0; GLOBAL_STATE_CODE(); g_assert(bs->quiesce_counter > 0); g_assert(!bs->refcnt); while (bs->quiesce_counter) { - bdrv_do_drained_end(bs, false, NULL, true, &drained_end_counter); + bdrv_do_drained_end(bs, false, NULL, true); } - BDRV_POLL_WHILE(bs, qatomic_read(&drained_end_counter) > 0); } void bdrv_drain_all_end(void) { BlockDriverState *bs = NULL; - int drained_end_counter = 0; GLOBAL_STATE_CODE(); /* @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_end(void) AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - bdrv_do_drained_end(bs, false, NULL, true, &drained_end_counter); + bdrv_do_drained_end(bs, false, NULL, true); aio_context_release(aio_context); } assert(qemu_get_current_aio_context() == qemu_get_aio_context()); - AIO_WAIT_WHILE(NULL, qatomic_read(&drained_end_counter) > 0); - assert(bdrv_drain_all_count > 0); bdrv_drain_all_count--; } diff --git a/blockjob.c b/blockjob.c index XXXXXXX..XXXXXXX 100644 --- a/blockjob.c +++ b/blockjob.c @@ -XXX,XX +XXX,XX @@ static bool child_job_drained_poll(BdrvChild *c) } } -static void child_job_drained_end(BdrvChild *c, int *drained_end_counter) +static void child_job_drained_end(BdrvChild *c) { BlockJob *job = c->opaque; job_resume(&job->job); -- 2.38.1 bdrv_drain_invoke() has now two entirely separate cases that share no code any more and are selected depending on a bool parameter. Each case has only one caller. Just inline the function. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221118174110.55183-6-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/io.c | 23 ++++++----------------- 1 file changed, 6 insertions(+), 17 deletions(-) diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ typedef struct { bool ignore_bds_parents; } BdrvCoDrainData; -/* Recursively call BlockDriver.bdrv_drain_begin/end callbacks */ -static void bdrv_drain_invoke(BlockDriverState *bs, bool begin) -{ - if (!bs->drv || (begin && !bs->drv->bdrv_drain_begin) || - (!begin && !bs->drv->bdrv_drain_end)) { - return; - } - - if (begin) { - bs->drv->bdrv_drain_begin(bs); - } else { - bs->drv->bdrv_drain_end(bs); - } -} - /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */ bool bdrv_drain_poll(BlockDriverState *bs, bool recursive, BdrvChild *ignore_parent, bool ignore_bds_parents) @@ -XXX,XX +XXX,XX @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, } bdrv_parent_drained_begin(bs, parent, ignore_bds_parents); - bdrv_drain_invoke(bs, true); + if (bs->drv && bs->drv->bdrv_drain_begin) { + bs->drv->bdrv_drain_begin(bs); + } } static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive, @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive, assert(bs->quiesce_counter > 0); /* Re-enable things in child-to-parent order */ - bdrv_drain_invoke(bs, false); + if (bs->drv && bs->drv->bdrv_drain_end) { + bs->drv->bdrv_drain_end(bs); + } bdrv_parent_drained_end(bs, parent, ignore_bds_parents); old_quiesce_counter = qatomic_fetch_dec(&bs->quiesce_counter); -- 2.38.1 Callers don't agree whether bdrv_reopen_queue_child() should be called with the AioContext lock held or not. Standardise on holding the lock (as done by QMP blockdev-reopen and the replication block driver) and fix bdrv_reopen() to do the same. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221118174110.55183-7-kwolf@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static bool bdrv_recurse_has_child(BlockDriverState *bs, * bs_queue, or the existing bs_queue being used. * * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple(). + * + * To be called with bs->aio_context locked. */ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, BlockDriverState *bs, @@ -XXX,XX +XXX,XX @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, return bs_queue; } +/* To be called with bs->aio_context locked */ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, BlockDriverState *bs, QDict *options, bool keep_old_opts) @@ -XXX,XX +XXX,XX @@ int bdrv_reopen(BlockDriverState *bs, QDict *opts, bool keep_old_opts, GLOBAL_STATE_CODE(); bdrv_subtree_drained_begin(bs); + queue = bdrv_reopen_queue(NULL, bs, opts, keep_old_opts); + if (ctx != qemu_get_aio_context()) { aio_context_release(ctx); } - - queue = bdrv_reopen_queue(NULL, bs, opts, keep_old_opts); ret = bdrv_reopen_multiple(queue, errp); if (ctx != qemu_get_aio_context()) { -- 2.38.1 bdrv_reopen() and friends use subtree drains as a lazy way of covering all the nodes they touch. Turns out that this lazy way is a lot more complicated than just draining the nodes individually, even not accounting for the additional complexity in the drain mechanism itself. Simplify the code by switching to draining the individual nodes that are already managed in the BlockReopenQueue anyway. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221118174110.55183-8-kwolf@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 16 +++++++++------- block/replication.c | 6 ------ blockdev.c | 13 ------------- 3 files changed, 9 insertions(+), 26 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static bool bdrv_recurse_has_child(BlockDriverState *bs, * returns a pointer to bs_queue, which is either the newly allocated * bs_queue, or the existing bs_queue being used. * - * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple(). + * bs is drained here and undrained by bdrv_reopen_queue_free(). * * To be called with bs->aio_context locked. */ @@ -XXX,XX +XXX,XX @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, int flags; QemuOpts *opts; - /* Make sure that the caller remembered to use a drained section. This is - * important to avoid graph changes between the recursive queuing here and - * bdrv_reopen_multiple(). */ - assert(bs->quiesce_counter > 0); GLOBAL_STATE_CODE(); + bdrv_drained_begin(bs); + if (bs_queue == NULL) { bs_queue = g_new0(BlockReopenQueue, 1); QTAILQ_INIT(bs_queue); @@ -XXX,XX +XXX,XX @@ void bdrv_reopen_queue_free(BlockReopenQueue *bs_queue) if (bs_queue) { BlockReopenQueueEntry *bs_entry, *next; QTAILQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { + AioContext *ctx = bdrv_get_aio_context(bs_entry->state.bs); + + aio_context_acquire(ctx); + bdrv_drained_end(bs_entry->state.bs); + aio_context_release(ctx); + qobject_unref(bs_entry->state.explicit_options); qobject_unref(bs_entry->state.options); g_free(bs_entry); @@ -XXX,XX +XXX,XX @@ int bdrv_reopen(BlockDriverState *bs, QDict *opts, bool keep_old_opts, GLOBAL_STATE_CODE(); - bdrv_subtree_drained_begin(bs); queue = bdrv_reopen_queue(NULL, bs, opts, keep_old_opts); if (ctx != qemu_get_aio_context()) { @@ -XXX,XX +XXX,XX @@ int bdrv_reopen(BlockDriverState *bs, QDict *opts, bool keep_old_opts, if (ctx != qemu_get_aio_context()) { aio_context_acquire(ctx); } - bdrv_subtree_drained_end(bs); return ret; } diff --git a/block/replication.c b/block/replication.c index XXXXXXX..XXXXXXX 100644 --- a/block/replication.c +++ b/block/replication.c @@ -XXX,XX +XXX,XX @@ static void reopen_backing_file(BlockDriverState *bs, bool writable, s->orig_secondary_read_only = bdrv_is_read_only(secondary_disk->bs); } - bdrv_subtree_drained_begin(hidden_disk->bs); - bdrv_subtree_drained_begin(secondary_disk->bs); - if (s->orig_hidden_read_only) { QDict *opts = qdict_new(); qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable); @@ -XXX,XX +XXX,XX @@ static void reopen_backing_file(BlockDriverState *bs, bool writable, aio_context_acquire(ctx); } } - - bdrv_subtree_drained_end(hidden_disk->bs); - bdrv_subtree_drained_end(secondary_disk->bs); } static void backup_job_cleanup(BlockDriverState *bs) diff --git a/blockdev.c b/blockdev.c index XXXXXXX..XXXXXXX 100644 --- a/blockdev.c +++ b/blockdev.c @@ -XXX,XX +XXX,XX @@ fail: void qmp_blockdev_reopen(BlockdevOptionsList *reopen_list, Error **errp) { BlockReopenQueue *queue = NULL; - GSList *drained = NULL; - GSList *p; /* Add each one of the BDS that we want to reopen to the queue */ for (; reopen_list != NULL; reopen_list = reopen_list->next) { @@ -XXX,XX +XXX,XX @@ void qmp_blockdev_reopen(BlockdevOptionsList *reopen_list, Error **errp) ctx = bdrv_get_aio_context(bs); aio_context_acquire(ctx); - bdrv_subtree_drained_begin(bs); queue = bdrv_reopen_queue(queue, bs, qdict, false); - drained = g_slist_prepend(drained, bs); aio_context_release(ctx); } @@ -XXX,XX +XXX,XX @@ void qmp_blockdev_reopen(BlockdevOptionsList *reopen_list, Error **errp) fail: bdrv_reopen_queue_free(queue); - for (p = drained; p; p = p->next) { - BlockDriverState *bs = p->data; - AioContext *ctx = bdrv_get_aio_context(bs); - - aio_context_acquire(ctx); - bdrv_subtree_drained_end(bs); - aio_context_release(ctx); - } - g_slist_free(drained); } void qmp_blockdev_del(const char *node_name, Error **errp) -- 2.38.1 Instead of using a subtree drain from the top node (which also drains child nodes of base that we're not even interested in), use a normal drain for base, which automatically drains all of the parents, too. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221118174110.55183-9-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, GLOBAL_STATE_CODE(); bdrv_ref(top); - bdrv_subtree_drained_begin(top); + bdrv_drained_begin(base); if (!top->drv || !base->drv) { goto exit; @@ -XXX,XX +XXX,XX @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, ret = 0; exit: - bdrv_subtree_drained_end(top); + bdrv_drained_end(base); bdrv_unref(top); return ret; } -- 2.38.1 The subtree drain was introduced in commit b1e1af394d9 as a way to avoid graph changes between finding the base node and changing the block graph as necessary on completion of the image streaming job. The block graph could change between these two points because bdrv_set_backing_hd() first drains the parent node, which involved polling and can do anything. Subtree draining was an imperfect way to make this less likely (because with it, fewer callbacks are called during this window). Everyone agreed that it's not really the right solution, and it was only committed as a stopgap solution. This replaces the subtree drain with a solution that simply drains the parent node before we try to find the base node, and then call a version of bdrv_set_backing_hd() that doesn't drain, but just asserts that the parent node is already drained. This way, any graph changes caused by draining happen before we start looking at the graph and things stay consistent between finding the base node and changing the graph. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221118174110.55183-10-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-global-state.h | 3 +++ block.c | 17 ++++++++++++++--- block/stream.c | 26 ++++++++++++++++---------- 3 files changed, 33 insertions(+), 13 deletions(-) diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -XXX,XX +XXX,XX @@ int bdrv_open_file_child(const char *filename, BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp); int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, Error **errp); +int bdrv_set_backing_hd_drained(BlockDriverState *bs, + BlockDriverState *backing_hd, + Error **errp); int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, const char *bdref_key, Error **errp); BlockDriverState *bdrv_open(const char *filename, const char *reference, diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static int bdrv_set_backing_noperm(BlockDriverState *bs, return bdrv_set_file_or_backing_noperm(bs, backing_hd, true, tran, errp); } -int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, - Error **errp) +int bdrv_set_backing_hd_drained(BlockDriverState *bs, + BlockDriverState *backing_hd, + Error **errp) { int ret; Transaction *tran = tran_new(); GLOBAL_STATE_CODE(); - bdrv_drained_begin(bs); + assert(bs->quiesce_counter > 0); ret = bdrv_set_backing_noperm(bs, backing_hd, tran, errp); if (ret < 0) { @@ -XXX,XX +XXX,XX @@ int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, ret = bdrv_refresh_perms(bs, tran, errp); out: tran_finalize(tran, ret); + return ret; +} +int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, + Error **errp) +{ + int ret; + GLOBAL_STATE_CODE(); + + bdrv_drained_begin(bs); + ret = bdrv_set_backing_hd_drained(bs, backing_hd, errp); bdrv_drained_end(bs); return ret; diff --git a/block/stream.c b/block/stream.c index XXXXXXX..XXXXXXX 100644 --- a/block/stream.c +++ b/block/stream.c @@ -XXX,XX +XXX,XX @@ static int stream_prepare(Job *job) bdrv_cor_filter_drop(s->cor_filter_bs); s->cor_filter_bs = NULL; - bdrv_subtree_drained_begin(s->above_base); + /* + * bdrv_set_backing_hd() requires that unfiltered_bs is drained. Drain + * already here and use bdrv_set_backing_hd_drained() instead because + * the polling during drained_begin() might change the graph, and if we do + * this only later, we may end up working with the wrong base node (or it + * might even have gone away by the time we want to use it). + */ + bdrv_drained_begin(unfiltered_bs); base = bdrv_filter_or_cow_bs(s->above_base); - if (base) { - bdrv_ref(base); - } - unfiltered_base = bdrv_skip_filters(base); if (bdrv_cow_child(unfiltered_bs)) { @@ -XXX,XX +XXX,XX @@ static int stream_prepare(Job *job) } } - bdrv_set_backing_hd(unfiltered_bs, base, &local_err); + bdrv_set_backing_hd_drained(unfiltered_bs, base, &local_err); + + /* + * This call will do I/O, so the graph can change again from here on. + * We have already completed the graph change, so we are not in danger + * of operating on the wrong node any more if this happens. + */ ret = bdrv_change_backing_file(unfiltered_bs, base_id, base_fmt, false); if (local_err) { error_report_err(local_err); @@ -XXX,XX +XXX,XX @@ static int stream_prepare(Job *job) } out: - if (base) { - bdrv_unref(base); - } - bdrv_subtree_drained_end(s->above_base); + bdrv_drained_end(unfiltered_bs); return ret; } -- 2.38.1 Subtree drains are not used any more. Remove them. After this, BdrvChildClass.attach/detach() don't poll any more. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221118174110.55183-11-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-io.h | 18 +-- include/block/block_int-common.h | 1 - include/block/block_int-io.h | 12 -- block.c | 20 +-- block/io.c | 121 +++----------- tests/unit/test-bdrv-drain.c | 261 ++----------------------------- 6 files changed, 44 insertions(+), 389 deletions(-) diff --git a/include/block/block-io.h b/include/block/block-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -XXX,XX +XXX,XX @@ void bdrv_parent_drained_end_single(BdrvChild *c); /** * bdrv_drain_poll: * - * Poll for pending requests in @bs, its parents (except for @ignore_parent), - * and if @recursive is true its children as well (used for subtree drain). + * Poll for pending requests in @bs and its parents (except for @ignore_parent). * * If @ignore_bds_parents is true, parents that are BlockDriverStates must * ignore the drain request because they will be drained separately (used for @@ -XXX,XX +XXX,XX @@ void bdrv_parent_drained_end_single(BdrvChild *c); * * This is part of bdrv_drained_begin. */ -bool bdrv_drain_poll(BlockDriverState *bs, bool recursive, - BdrvChild *ignore_parent, bool ignore_bds_parents); +bool bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent, + bool ignore_bds_parents); /** * bdrv_drained_begin: @@ -XXX,XX +XXX,XX @@ void bdrv_drained_begin(BlockDriverState *bs); void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent, bool ignore_bds_parents); -/** - * Like bdrv_drained_begin, but recursively begins a quiesced section for - * exclusive access to all child nodes as well. - */ -void bdrv_subtree_drained_begin(BlockDriverState *bs); - /** * bdrv_drained_end: * @@ -XXX,XX +XXX,XX @@ void bdrv_subtree_drained_begin(BlockDriverState *bs); */ void bdrv_drained_end(BlockDriverState *bs); -/** - * End a quiescent section started by bdrv_subtree_drained_begin(). - */ -void bdrv_subtree_drained_end(BlockDriverState *bs); - #endif /* BLOCK_IO_H */ diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -XXX,XX +XXX,XX @@ struct BlockDriverState { /* Accessed with atomic ops. */ int quiesce_counter; - int recursive_quiesce_counter; unsigned int write_gen; /* Current data generation */ diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int-io.h +++ b/include/block/block_int-io.h @@ -XXX,XX +XXX,XX @@ void bdrv_bsc_invalidate_range(BlockDriverState *bs, */ void bdrv_bsc_fill(BlockDriverState *bs, int64_t offset, int64_t bytes); - -/* - * "I/O or GS" API functions. These functions can run without - * the BQL, but only in one specific iothread/main loop. - * - * See include/block/block-io.h for more information about - * the "I/O or GS" API. - */ - -void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent); -void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent); - #endif /* BLOCK_INT_IO_H */ diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static void bdrv_child_cb_drained_begin(BdrvChild *child) static bool bdrv_child_cb_drained_poll(BdrvChild *child) { BlockDriverState *bs = child->opaque; - return bdrv_drain_poll(bs, false, NULL, false); + return bdrv_drain_poll(bs, NULL, false); } static void bdrv_child_cb_drained_end(BdrvChild *child) @@ -XXX,XX +XXX,XX @@ static void bdrv_child_cb_attach(BdrvChild *child) assert(!bs->file); bs->file = child; } - - bdrv_apply_subtree_drain(child, bs); } static void bdrv_child_cb_detach(BdrvChild *child) @@ -XXX,XX +XXX,XX @@ static void bdrv_child_cb_detach(BdrvChild *child) bdrv_backing_detach(child); } - bdrv_unapply_subtree_drain(child, bs); - assert_bdrv_graph_writable(bs); QLIST_REMOVE(child, next); if (child == bs->backing) { @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, } if (old_bs) { - /* Detach first so that the recursive drain sections coming from @child - * are already gone and we only end the drain sections that came from - * elsewhere. */ if (child->klass->detach) { child->klass->detach(child); } @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); /* - * Detaching the old node may have led to the new node's - * quiesce_counter having been decreased. Not a problem, we - * just need to recognize this here and then invoke - * drained_end appropriately more often. + * Polling in bdrv_parent_drained_begin_single() may have led to the new + * node's quiesce_counter having been decreased. Not a problem, we just + * need to recognize this here and then invoke drained_end appropriately + * more often. */ assert(new_bs->quiesce_counter <= new_bs_quiesce_counter); drain_saldo += new_bs->quiesce_counter - new_bs_quiesce_counter; - /* Attach only after starting new drained sections, so that recursive - * drain sections coming from @child don't get an extra .drained_begin - * callback. */ if (child->klass->attach) { child->klass->attach(child); } diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ typedef struct { BlockDriverState *bs; bool done; bool begin; - bool recursive; bool poll; BdrvChild *parent; bool ignore_bds_parents; } BdrvCoDrainData; /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */ -bool bdrv_drain_poll(BlockDriverState *bs, bool recursive, - BdrvChild *ignore_parent, bool ignore_bds_parents) +bool bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent, + bool ignore_bds_parents) { - BdrvChild *child, *next; IO_OR_GS_CODE(); if (bdrv_parent_drained_poll(bs, ignore_parent, ignore_bds_parents)) { @@ -XXX,XX +XXX,XX @@ bool bdrv_drain_poll(BlockDriverState *bs, bool recursive, return true; } - if (recursive) { - assert(!ignore_bds_parents); - QLIST_FOREACH_SAFE(child, &bs->children, next, next) { - if (bdrv_drain_poll(child->bs, recursive, child, false)) { - return true; - } - } - } - return false; } -static bool bdrv_drain_poll_top_level(BlockDriverState *bs, bool recursive, +static bool bdrv_drain_poll_top_level(BlockDriverState *bs, BdrvChild *ignore_parent) { - return bdrv_drain_poll(bs, recursive, ignore_parent, false); + return bdrv_drain_poll(bs, ignore_parent, false); } -static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive, - BdrvChild *parent, bool ignore_bds_parents, - bool poll); -static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive, - BdrvChild *parent, bool ignore_bds_parents); +static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, + bool ignore_bds_parents, bool poll); +static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent, + bool ignore_bds_parents); static void bdrv_co_drain_bh_cb(void *opaque) { @@ -XXX,XX +XXX,XX @@ static void bdrv_co_drain_bh_cb(void *opaque) aio_context_acquire(ctx); bdrv_dec_in_flight(bs); if (data->begin) { - bdrv_do_drained_begin(bs, data->recursive, data->parent, - data->ignore_bds_parents, data->poll); + bdrv_do_drained_begin(bs, data->parent, data->ignore_bds_parents, + data->poll); } else { assert(!data->poll); - bdrv_do_drained_end(bs, data->recursive, data->parent, - data->ignore_bds_parents); + bdrv_do_drained_end(bs, data->parent, data->ignore_bds_parents); } aio_context_release(ctx); } else { @@ -XXX,XX +XXX,XX @@ static void bdrv_co_drain_bh_cb(void *opaque) } static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, - bool begin, bool recursive, + bool begin, BdrvChild *parent, bool ignore_bds_parents, bool poll) @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, .bs = bs, .done = false, .begin = begin, - .recursive = recursive, .parent = parent, .ignore_bds_parents = ignore_bds_parents, .poll = poll, @@ -XXX,XX +XXX,XX @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, } } -static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive, - BdrvChild *parent, bool ignore_bds_parents, - bool poll) +static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, + bool ignore_bds_parents, bool poll) { - BdrvChild *child, *next; - if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(bs, true, recursive, parent, ignore_bds_parents, - poll); + bdrv_co_yield_to_drain(bs, true, parent, ignore_bds_parents, poll); return; } bdrv_do_drained_begin_quiesce(bs, parent, ignore_bds_parents); - if (recursive) { - assert(!ignore_bds_parents); - bs->recursive_quiesce_counter++; - QLIST_FOREACH_SAFE(child, &bs->children, next, next) { - bdrv_do_drained_begin(child->bs, true, child, ignore_bds_parents, - false); - } - } - /* * Wait for drained requests to finish. * @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive, */ if (poll) { assert(!ignore_bds_parents); - BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, recursive, parent)); + BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, parent)); } } void bdrv_drained_begin(BlockDriverState *bs) { IO_OR_GS_CODE(); - bdrv_do_drained_begin(bs, false, NULL, false, true); -} - -void bdrv_subtree_drained_begin(BlockDriverState *bs) -{ - IO_OR_GS_CODE(); - bdrv_do_drained_begin(bs, true, NULL, false, true); + bdrv_do_drained_begin(bs, NULL, false, true); } /** * This function does not poll, nor must any of its recursively called * functions. */ -static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive, - BdrvChild *parent, bool ignore_bds_parents) +static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent, + bool ignore_bds_parents) { - BdrvChild *child; int old_quiesce_counter; if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(bs, false, recursive, parent, ignore_bds_parents, - false); + bdrv_co_yield_to_drain(bs, false, parent, ignore_bds_parents, false); return; } assert(bs->quiesce_counter > 0); @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive, if (old_quiesce_counter == 1) { aio_enable_external(bdrv_get_aio_context(bs)); } - - if (recursive) { - assert(!ignore_bds_parents); - bs->recursive_quiesce_counter--; - QLIST_FOREACH(child, &bs->children, next) { - bdrv_do_drained_end(child->bs, true, child, ignore_bds_parents); - } - } } void bdrv_drained_end(BlockDriverState *bs) { IO_OR_GS_CODE(); - bdrv_do_drained_end(bs, false, NULL, false); -} - -void bdrv_subtree_drained_end(BlockDriverState *bs) -{ - IO_OR_GS_CODE(); - bdrv_do_drained_end(bs, true, NULL, false); -} - -void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent) -{ - int i; - IO_OR_GS_CODE(); - - for (i = 0; i < new_parent->recursive_quiesce_counter; i++) { - bdrv_do_drained_begin(child->bs, true, child, false, true); - } -} - -void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent) -{ - int i; - IO_OR_GS_CODE(); - - for (i = 0; i < old_parent->recursive_quiesce_counter; i++) { - bdrv_do_drained_end(child->bs, true, child, false); - } + bdrv_do_drained_end(bs, NULL, false); } void bdrv_drain(BlockDriverState *bs) @@ -XXX,XX +XXX,XX @@ static bool bdrv_drain_all_poll(void) while ((bs = bdrv_next_all_states(bs))) { AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - result |= bdrv_drain_poll(bs, false, NULL, true); + result |= bdrv_drain_poll(bs, NULL, true); aio_context_release(aio_context); } @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_begin(void) GLOBAL_STATE_CODE(); if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(NULL, true, false, NULL, true, true); + bdrv_co_yield_to_drain(NULL, true, NULL, true, true); return; } @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_begin(void) AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - bdrv_do_drained_begin(bs, false, NULL, true, false); + bdrv_do_drained_begin(bs, NULL, true, false); aio_context_release(aio_context); } @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_end_quiesce(BlockDriverState *bs) g_assert(!bs->refcnt); while (bs->quiesce_counter) { - bdrv_do_drained_end(bs, false, NULL, true); + bdrv_do_drained_end(bs, NULL, true); } } @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_end(void) AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - bdrv_do_drained_end(bs, false, NULL, true); + bdrv_do_drained_end(bs, NULL, true); aio_context_release(aio_context); } diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-drain.c +++ b/tests/unit/test-bdrv-drain.c @@ -XXX,XX +XXX,XX @@ static void call_in_coroutine(void (*entry)(void)) enum drain_type { BDRV_DRAIN_ALL, BDRV_DRAIN, - BDRV_SUBTREE_DRAIN, DRAIN_TYPE_MAX, }; @@ -XXX,XX +XXX,XX @@ static void do_drain_begin(enum drain_type drain_type, BlockDriverState *bs) switch (drain_type) { case BDRV_DRAIN_ALL: bdrv_drain_all_begin(); break; case BDRV_DRAIN: bdrv_drained_begin(bs); break; - case BDRV_SUBTREE_DRAIN: bdrv_subtree_drained_begin(bs); break; default: g_assert_not_reached(); } } @@ -XXX,XX +XXX,XX @@ static void do_drain_end(enum drain_type drain_type, BlockDriverState *bs) switch (drain_type) { case BDRV_DRAIN_ALL: bdrv_drain_all_end(); break; case BDRV_DRAIN: bdrv_drained_end(bs); break; - case BDRV_SUBTREE_DRAIN: bdrv_subtree_drained_end(bs); break; default: g_assert_not_reached(); } } @@ -XXX,XX +XXX,XX @@ static void test_drv_cb_drain(void) test_drv_cb_common(BDRV_DRAIN, false); } -static void test_drv_cb_drain_subtree(void) -{ - test_drv_cb_common(BDRV_SUBTREE_DRAIN, true); -} - static void test_drv_cb_co_drain_all(void) { call_in_coroutine(test_drv_cb_drain_all); @@ -XXX,XX +XXX,XX @@ static void test_drv_cb_co_drain(void) call_in_coroutine(test_drv_cb_drain); } -static void test_drv_cb_co_drain_subtree(void) -{ - call_in_coroutine(test_drv_cb_drain_subtree); -} - static void test_quiesce_common(enum drain_type drain_type, bool recursive) { BlockBackend *blk; @@ -XXX,XX +XXX,XX @@ static void test_quiesce_drain(void) test_quiesce_common(BDRV_DRAIN, false); } -static void test_quiesce_drain_subtree(void) -{ - test_quiesce_common(BDRV_SUBTREE_DRAIN, true); -} - static void test_quiesce_co_drain_all(void) { call_in_coroutine(test_quiesce_drain_all); @@ -XXX,XX +XXX,XX @@ static void test_quiesce_co_drain(void) call_in_coroutine(test_quiesce_drain); } -static void test_quiesce_co_drain_subtree(void) -{ - call_in_coroutine(test_quiesce_drain_subtree); -} - static void test_nested(void) { BlockBackend *blk; @@ -XXX,XX +XXX,XX @@ static void test_nested(void) blk_unref(blk); } -static void test_multiparent(void) -{ - BlockBackend *blk_a, *blk_b; - BlockDriverState *bs_a, *bs_b, *backing; - BDRVTestState *a_s, *b_s, *backing_s; - - blk_a = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); - bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR, - &error_abort); - a_s = bs_a->opaque; - blk_insert_bs(blk_a, bs_a, &error_abort); - - blk_b = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); - bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR, - &error_abort); - b_s = bs_b->opaque; - blk_insert_bs(blk_b, bs_b, &error_abort); - - backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort); - backing_s = backing->opaque; - bdrv_set_backing_hd(bs_a, backing, &error_abort); - bdrv_set_backing_hd(bs_b, backing, &error_abort); - - g_assert_cmpint(bs_a->quiesce_counter, ==, 0); - g_assert_cmpint(bs_b->quiesce_counter, ==, 0); - g_assert_cmpint(backing->quiesce_counter, ==, 0); - g_assert_cmpint(a_s->drain_count, ==, 0); - g_assert_cmpint(b_s->drain_count, ==, 0); - g_assert_cmpint(backing_s->drain_count, ==, 0); - - do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a); - - g_assert_cmpint(bs_a->quiesce_counter, ==, 1); - g_assert_cmpint(bs_b->quiesce_counter, ==, 1); - g_assert_cmpint(backing->quiesce_counter, ==, 1); - g_assert_cmpint(a_s->drain_count, ==, 1); - g_assert_cmpint(b_s->drain_count, ==, 1); - g_assert_cmpint(backing_s->drain_count, ==, 1); - - do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b); - - g_assert_cmpint(bs_a->quiesce_counter, ==, 2); - g_assert_cmpint(bs_b->quiesce_counter, ==, 2); - g_assert_cmpint(backing->quiesce_counter, ==, 2); - g_assert_cmpint(a_s->drain_count, ==, 2); - g_assert_cmpint(b_s->drain_count, ==, 2); - g_assert_cmpint(backing_s->drain_count, ==, 2); - - do_drain_end(BDRV_SUBTREE_DRAIN, bs_b); - - g_assert_cmpint(bs_a->quiesce_counter, ==, 1); - g_assert_cmpint(bs_b->quiesce_counter, ==, 1); - g_assert_cmpint(backing->quiesce_counter, ==, 1); - g_assert_cmpint(a_s->drain_count, ==, 1); - g_assert_cmpint(b_s->drain_count, ==, 1); - g_assert_cmpint(backing_s->drain_count, ==, 1); - - do_drain_end(BDRV_SUBTREE_DRAIN, bs_a); - - g_assert_cmpint(bs_a->quiesce_counter, ==, 0); - g_assert_cmpint(bs_b->quiesce_counter, ==, 0); - g_assert_cmpint(backing->quiesce_counter, ==, 0); - g_assert_cmpint(a_s->drain_count, ==, 0); - g_assert_cmpint(b_s->drain_count, ==, 0); - g_assert_cmpint(backing_s->drain_count, ==, 0); - - bdrv_unref(backing); - bdrv_unref(bs_a); - bdrv_unref(bs_b); - blk_unref(blk_a); - blk_unref(blk_b); -} - -static void test_graph_change_drain_subtree(void) -{ - BlockBackend *blk_a, *blk_b; - BlockDriverState *bs_a, *bs_b, *backing; - BDRVTestState *a_s, *b_s, *backing_s; - - blk_a = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); - bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR, - &error_abort); - a_s = bs_a->opaque; - blk_insert_bs(blk_a, bs_a, &error_abort); - - blk_b = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); - bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR, - &error_abort); - b_s = bs_b->opaque; - blk_insert_bs(blk_b, bs_b, &error_abort); - - backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort); - backing_s = backing->opaque; - bdrv_set_backing_hd(bs_a, backing, &error_abort); - - g_assert_cmpint(bs_a->quiesce_counter, ==, 0); - g_assert_cmpint(bs_b->quiesce_counter, ==, 0); - g_assert_cmpint(backing->quiesce_counter, ==, 0); - g_assert_cmpint(a_s->drain_count, ==, 0); - g_assert_cmpint(b_s->drain_count, ==, 0); - g_assert_cmpint(backing_s->drain_count, ==, 0); - - do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a); - do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a); - do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a); - do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b); - do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b); - - bdrv_set_backing_hd(bs_b, backing, &error_abort); - g_assert_cmpint(bs_a->quiesce_counter, ==, 5); - g_assert_cmpint(bs_b->quiesce_counter, ==, 5); - g_assert_cmpint(backing->quiesce_counter, ==, 5); - g_assert_cmpint(a_s->drain_count, ==, 5); - g_assert_cmpint(b_s->drain_count, ==, 5); - g_assert_cmpint(backing_s->drain_count, ==, 5); - - bdrv_set_backing_hd(bs_b, NULL, &error_abort); - g_assert_cmpint(bs_a->quiesce_counter, ==, 3); - g_assert_cmpint(bs_b->quiesce_counter, ==, 2); - g_assert_cmpint(backing->quiesce_counter, ==, 3); - g_assert_cmpint(a_s->drain_count, ==, 3); - g_assert_cmpint(b_s->drain_count, ==, 2); - g_assert_cmpint(backing_s->drain_count, ==, 3); - - bdrv_set_backing_hd(bs_b, backing, &error_abort); - g_assert_cmpint(bs_a->quiesce_counter, ==, 5); - g_assert_cmpint(bs_b->quiesce_counter, ==, 5); - g_assert_cmpint(backing->quiesce_counter, ==, 5); - g_assert_cmpint(a_s->drain_count, ==, 5); - g_assert_cmpint(b_s->drain_count, ==, 5); - g_assert_cmpint(backing_s->drain_count, ==, 5); - - do_drain_end(BDRV_SUBTREE_DRAIN, bs_b); - do_drain_end(BDRV_SUBTREE_DRAIN, bs_b); - do_drain_end(BDRV_SUBTREE_DRAIN, bs_a); - do_drain_end(BDRV_SUBTREE_DRAIN, bs_a); - do_drain_end(BDRV_SUBTREE_DRAIN, bs_a); - - g_assert_cmpint(bs_a->quiesce_counter, ==, 0); - g_assert_cmpint(bs_b->quiesce_counter, ==, 0); - g_assert_cmpint(backing->quiesce_counter, ==, 0); - g_assert_cmpint(a_s->drain_count, ==, 0); - g_assert_cmpint(b_s->drain_count, ==, 0); - g_assert_cmpint(backing_s->drain_count, ==, 0); - - bdrv_unref(backing); - bdrv_unref(bs_a); - bdrv_unref(bs_b); - blk_unref(blk_a); - blk_unref(blk_b); -} - static void test_graph_change_drain_all(void) { BlockBackend *blk_a, *blk_b; @@ -XXX,XX +XXX,XX @@ static void test_iothread_drain(void) test_iothread_common(BDRV_DRAIN, 1); } -static void test_iothread_drain_subtree(void) -{ - test_iothread_common(BDRV_SUBTREE_DRAIN, 0); - test_iothread_common(BDRV_SUBTREE_DRAIN, 1); -} - typedef struct TestBlockJob { BlockJob common; @@ -XXX,XX +XXX,XX @@ enum test_job_result { enum test_job_drain_node { TEST_JOB_DRAIN_SRC, TEST_JOB_DRAIN_SRC_CHILD, - TEST_JOB_DRAIN_SRC_PARENT, }; static void test_blockjob_common_drain_node(enum drain_type drain_type, @@ -XXX,XX +XXX,XX @@ static void test_blockjob_common_drain_node(enum drain_type drain_type, case TEST_JOB_DRAIN_SRC_CHILD: drain_bs = src_backing; break; - case TEST_JOB_DRAIN_SRC_PARENT: - drain_bs = src_overlay; - break; default: g_assert_not_reached(); } @@ -XXX,XX +XXX,XX @@ static void test_blockjob_common(enum drain_type drain_type, bool use_iothread, TEST_JOB_DRAIN_SRC); test_blockjob_common_drain_node(drain_type, use_iothread, result, TEST_JOB_DRAIN_SRC_CHILD); - if (drain_type == BDRV_SUBTREE_DRAIN) { - test_blockjob_common_drain_node(drain_type, use_iothread, result, - TEST_JOB_DRAIN_SRC_PARENT); - } } static void test_blockjob_drain_all(void) @@ -XXX,XX +XXX,XX @@ static void test_blockjob_drain(void) test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_SUCCESS); } -static void test_blockjob_drain_subtree(void) -{ - test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_SUCCESS); -} - static void test_blockjob_error_drain_all(void) { test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_RUN); @@ -XXX,XX +XXX,XX @@ static void test_blockjob_error_drain(void) test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_PREPARE); } -static void test_blockjob_error_drain_subtree(void) -{ - test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_FAIL_RUN); - test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_FAIL_PREPARE); -} - static void test_blockjob_iothread_drain_all(void) { test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_SUCCESS); @@ -XXX,XX +XXX,XX @@ static void test_blockjob_iothread_drain(void) test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_SUCCESS); } -static void test_blockjob_iothread_drain_subtree(void) -{ - test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_SUCCESS); -} - static void test_blockjob_iothread_error_drain_all(void) { test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_RUN); @@ -XXX,XX +XXX,XX @@ static void test_blockjob_iothread_error_drain(void) test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_PREPARE); } -static void test_blockjob_iothread_error_drain_subtree(void) -{ - test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_FAIL_RUN); - test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_FAIL_PREPARE); -} - typedef struct BDRVTestTopState { BdrvChild *wait_child; @@ -XXX,XX +XXX,XX @@ static void do_test_delete_by_drain(bool detach_instead_of_delete, bdrv_drain(child_bs); bdrv_unref(child_bs); break; - case BDRV_SUBTREE_DRAIN: - /* Would have to ref/unref bs here for !detach_instead_of_delete, but - * then the whole test becomes pointless because the graph changes - * don't occur during the drain any more. */ - assert(detach_instead_of_delete); - bdrv_subtree_drained_begin(bs); - bdrv_subtree_drained_end(bs); - break; case BDRV_DRAIN_ALL: bdrv_drain_all_begin(); bdrv_drain_all_end(); @@ -XXX,XX +XXX,XX @@ static void test_detach_by_drain(void) do_test_delete_by_drain(true, BDRV_DRAIN); } -static void test_detach_by_drain_subtree(void) -{ - do_test_delete_by_drain(true, BDRV_SUBTREE_DRAIN); -} - struct detach_by_parent_data { BlockDriverState *parent_b; @@ -XXX,XX +XXX,XX @@ static void test_detach_indirect(bool by_parent_cb) g_assert(acb != NULL); /* Drain and check the expected result */ - bdrv_subtree_drained_begin(parent_b); + bdrv_drained_begin(parent_b); + bdrv_drained_begin(a); + bdrv_drained_begin(b); + bdrv_drained_begin(c); g_assert(detach_by_parent_data.child_c != NULL); @@ -XXX,XX +XXX,XX @@ static void test_detach_indirect(bool by_parent_cb) g_assert(QLIST_NEXT(child_a, next) == NULL); g_assert_cmpint(parent_a->quiesce_counter, ==, 1); - g_assert_cmpint(parent_b->quiesce_counter, ==, 1); + g_assert_cmpint(parent_b->quiesce_counter, ==, 3); g_assert_cmpint(a->quiesce_counter, ==, 1); - g_assert_cmpint(b->quiesce_counter, ==, 0); + g_assert_cmpint(b->quiesce_counter, ==, 1); g_assert_cmpint(c->quiesce_counter, ==, 1); - bdrv_subtree_drained_end(parent_b); + bdrv_drained_end(parent_b); + bdrv_drained_end(a); + bdrv_drained_end(b); + bdrv_drained_end(c); bdrv_unref(parent_b); blk_unref(blk); @@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv) g_test_add_func("/bdrv-drain/driver-cb/drain_all", test_drv_cb_drain_all); g_test_add_func("/bdrv-drain/driver-cb/drain", test_drv_cb_drain); - g_test_add_func("/bdrv-drain/driver-cb/drain_subtree", - test_drv_cb_drain_subtree); g_test_add_func("/bdrv-drain/driver-cb/co/drain_all", test_drv_cb_co_drain_all); g_test_add_func("/bdrv-drain/driver-cb/co/drain", test_drv_cb_co_drain); - g_test_add_func("/bdrv-drain/driver-cb/co/drain_subtree", - test_drv_cb_co_drain_subtree); - g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all); g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain); - g_test_add_func("/bdrv-drain/quiesce/drain_subtree", - test_quiesce_drain_subtree); g_test_add_func("/bdrv-drain/quiesce/co/drain_all", test_quiesce_co_drain_all); g_test_add_func("/bdrv-drain/quiesce/co/drain", test_quiesce_co_drain); - g_test_add_func("/bdrv-drain/quiesce/co/drain_subtree", - test_quiesce_co_drain_subtree); g_test_add_func("/bdrv-drain/nested", test_nested); - g_test_add_func("/bdrv-drain/multiparent", test_multiparent); - g_test_add_func("/bdrv-drain/graph-change/drain_subtree", - test_graph_change_drain_subtree); g_test_add_func("/bdrv-drain/graph-change/drain_all", test_graph_change_drain_all); g_test_add_func("/bdrv-drain/iothread/drain_all", test_iothread_drain_all); g_test_add_func("/bdrv-drain/iothread/drain", test_iothread_drain); - g_test_add_func("/bdrv-drain/iothread/drain_subtree", - test_iothread_drain_subtree); g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all); g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain); - g_test_add_func("/bdrv-drain/blockjob/drain_subtree", - test_blockjob_drain_subtree); g_test_add_func("/bdrv-drain/blockjob/error/drain_all", test_blockjob_error_drain_all); g_test_add_func("/bdrv-drain/blockjob/error/drain", test_blockjob_error_drain); - g_test_add_func("/bdrv-drain/blockjob/error/drain_subtree", - test_blockjob_error_drain_subtree); g_test_add_func("/bdrv-drain/blockjob/iothread/drain_all", test_blockjob_iothread_drain_all); g_test_add_func("/bdrv-drain/blockjob/iothread/drain", test_blockjob_iothread_drain); - g_test_add_func("/bdrv-drain/blockjob/iothread/drain_subtree", - test_blockjob_iothread_drain_subtree); g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain_all", test_blockjob_iothread_error_drain_all); g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain", test_blockjob_iothread_error_drain); - g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain_subtree", - test_blockjob_iothread_error_drain_subtree); g_test_add_func("/bdrv-drain/deletion/drain", test_delete_by_drain); g_test_add_func("/bdrv-drain/detach/drain_all", test_detach_by_drain_all); g_test_add_func("/bdrv-drain/detach/drain", test_detach_by_drain); - g_test_add_func("/bdrv-drain/detach/drain_subtree", test_detach_by_drain_subtree); g_test_add_func("/bdrv-drain/detach/parent_cb", test_detach_by_parent_cb); g_test_add_func("/bdrv-drain/detach/driver_cb", test_detach_by_driver_cb); -- 2.38.1 We only need to call both the BlockDriver's callback and the parent callbacks when going from undrained to drained or vice versa. A second drain section doesn't make a difference for the driver or the parent, they weren't supposed to send new requests before and after the second drain. One thing that gets in the way is the 'ignore_bds_parents' parameter in bdrv_do_drained_begin_quiesce() and bdrv_do_drained_end(): It means that bdrv_drain_all_begin() increases bs->quiesce_counter, but does not quiesce the parent through BdrvChildClass callbacks. If an additional drain section is started now, bs->quiesce_counter will be non-zero, but we would still need to quiesce the parent through BdrvChildClass in order to keep things consistent (and unquiesce it on the matching bdrv_drained_end(), even though the counter would not reach 0 yet as long as the bdrv_drain_all() section is still active). Instead of keeping track of this, let's just get rid of the parameter. It was introduced in commit 6cd5c9d7b2d as an optimisation so that during bdrv_drain_all(), we wouldn't recursively drain all parents up to the root for each node, resulting in quadratic complexity. As it happens, calling the callbacks only once solves the same problem, so as of this patch, we'll still have O(n) complexity and ignore_bds_parents is not needed any more. This patch only ignores the 'ignore_bds_parents' parameter. It will be removed in a separate patch. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221118174110.55183-12-kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block_int-common.h | 8 ++++---- block.c | 25 +++++++------------------ block/io.c | 30 ++++++++++++++++++------------ tests/unit/test-bdrv-drain.c | 16 ++++++++++------ 4 files changed, 39 insertions(+), 40 deletions(-) diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -XXX,XX +XXX,XX @@ struct BdrvChild { bool frozen; /* - * How many times the parent of this child has been drained + * True if the parent of this child has been drained by this BdrvChild * (through klass->drained_*). - * Usually, this is equal to bs->quiesce_counter (potentially - * reduced by bdrv_drain_all_count). It may differ while the + * + * It is generally true if bs->quiesce_counter > 0. It may differ while the * child is entering or leaving a drained section. */ - int parent_quiesce_counter; + bool quiesced_parent; QLIST_ENTRY(BdrvChild) next; QLIST_ENTRY(BdrvChild) next_parent; diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, { BlockDriverState *old_bs = child->bs; int new_bs_quiesce_counter; - int drain_saldo; assert(!child->frozen); assert(old_bs != new_bs); @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs)); } - new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0); - drain_saldo = new_bs_quiesce_counter - child->parent_quiesce_counter; - /* * If the new child node is drained but the old one was not, flush * all outstanding requests to the old child node. */ - while (drain_saldo > 0 && child->klass->drained_begin) { + new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0); + if (new_bs_quiesce_counter && !child->quiesced_parent) { bdrv_parent_drained_begin_single(child, true); - drain_saldo--; } if (old_bs) { @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, if (new_bs) { assert_bdrv_graph_writable(new_bs); QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); - - /* - * Polling in bdrv_parent_drained_begin_single() may have led to the new - * node's quiesce_counter having been decreased. Not a problem, we just - * need to recognize this here and then invoke drained_end appropriately - * more often. - */ - assert(new_bs->quiesce_counter <= new_bs_quiesce_counter); - drain_saldo += new_bs->quiesce_counter - new_bs_quiesce_counter; - if (child->klass->attach) { child->klass->attach(child); } @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, /* * If the old child node was drained but the new one is not, allow * requests to come in only after the new node has been attached. + * + * Update new_bs_quiesce_counter because bdrv_parent_drained_begin_single() + * polls, which could have changed the value. */ - while (drain_saldo < 0 && child->klass->drained_end) { + new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0); + if (!new_bs_quiesce_counter && child->quiesced_parent) { bdrv_parent_drained_end_single(child); - drain_saldo++; } } diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ void bdrv_parent_drained_end_single(BdrvChild *c) { IO_OR_GS_CODE(); - assert(c->parent_quiesce_counter > 0); - c->parent_quiesce_counter--; + assert(c->quiesced_parent); + c->quiesced_parent = false; + if (c->klass->drained_end) { c->klass->drained_end(c); } @@ -XXX,XX +XXX,XX @@ void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll) { AioContext *ctx = bdrv_child_get_parent_aio_context(c); IO_OR_GS_CODE(); - c->parent_quiesce_counter++; + + assert(!c->quiesced_parent); + c->quiesced_parent = true; + if (c->klass->drained_begin) { c->klass->drained_begin(c); } @@ -XXX,XX +XXX,XX @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, /* Stop things in parent-to-child order */ if (qatomic_fetch_inc(&bs->quiesce_counter) == 0) { aio_disable_external(bdrv_get_aio_context(bs)); - } - bdrv_parent_drained_begin(bs, parent, ignore_bds_parents); - if (bs->drv && bs->drv->bdrv_drain_begin) { - bs->drv->bdrv_drain_begin(bs); + /* TODO Remove ignore_bds_parents, we don't consider it any more */ + bdrv_parent_drained_begin(bs, parent, false); + if (bs->drv && bs->drv->bdrv_drain_begin) { + bs->drv->bdrv_drain_begin(bs); + } } } @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent, assert(bs->quiesce_counter > 0); /* Re-enable things in child-to-parent order */ - if (bs->drv && bs->drv->bdrv_drain_end) { - bs->drv->bdrv_drain_end(bs); - } - bdrv_parent_drained_end(bs, parent, ignore_bds_parents); - old_quiesce_counter = qatomic_fetch_dec(&bs->quiesce_counter); if (old_quiesce_counter == 1) { + if (bs->drv && bs->drv->bdrv_drain_end) { + bs->drv->bdrv_drain_end(bs); + } + /* TODO Remove ignore_bds_parents, we don't consider it any more */ + bdrv_parent_drained_end(bs, parent, false); + aio_enable_external(bdrv_get_aio_context(bs)); } } diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-drain.c +++ b/tests/unit/test-bdrv-drain.c @@ -XXX,XX +XXX,XX @@ static void test_quiesce_common(enum drain_type drain_type, bool recursive) do_drain_begin(drain_type, bs); - g_assert_cmpint(bs->quiesce_counter, ==, 1); + if (drain_type == BDRV_DRAIN_ALL) { + g_assert_cmpint(bs->quiesce_counter, ==, 2); + } else { + g_assert_cmpint(bs->quiesce_counter, ==, 1); + } g_assert_cmpint(backing->quiesce_counter, ==, !!recursive); do_drain_end(drain_type, bs); @@ -XXX,XX +XXX,XX @@ static void test_nested(void) for (outer = 0; outer < DRAIN_TYPE_MAX; outer++) { for (inner = 0; inner < DRAIN_TYPE_MAX; inner++) { - int backing_quiesce = (outer != BDRV_DRAIN) + - (inner != BDRV_DRAIN); + int backing_quiesce = (outer == BDRV_DRAIN_ALL) + + (inner == BDRV_DRAIN_ALL); g_assert_cmpint(bs->quiesce_counter, ==, 0); g_assert_cmpint(backing->quiesce_counter, ==, 0); @@ -XXX,XX +XXX,XX @@ static void test_nested(void) do_drain_begin(outer, bs); do_drain_begin(inner, bs); - g_assert_cmpint(bs->quiesce_counter, ==, 2); + g_assert_cmpint(bs->quiesce_counter, ==, 2 + !!backing_quiesce); g_assert_cmpint(backing->quiesce_counter, ==, backing_quiesce); - g_assert_cmpint(s->drain_count, ==, 2); - g_assert_cmpint(backing_s->drain_count, ==, backing_quiesce); + g_assert_cmpint(s->drain_count, ==, 1); + g_assert_cmpint(backing_s->drain_count, ==, !!backing_quiesce); do_drain_end(inner, bs); do_drain_end(outer, bs); -- 2.38.1 ignore_bds_parents is now ignored during drain_begin and drain_end, so we can just remove it there. It is still a valid optimisation for drain_all in bdrv_drained_poll(), so leave it around there. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221118174110.55183-13-kwolf@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-io.h | 3 +-- block.c | 2 +- block/io.c | 58 +++++++++++++++------------------------- 3 files changed, 24 insertions(+), 39 deletions(-) diff --git a/include/block/block-io.h b/include/block/block-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -XXX,XX +XXX,XX @@ void bdrv_drained_begin(BlockDriverState *bs); * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already * running requests to complete. */ -void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, - BdrvChild *parent, bool ignore_bds_parents); +void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent); /** * bdrv_drained_end: diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static char *bdrv_child_get_parent_desc(BdrvChild *c) static void bdrv_child_cb_drained_begin(BdrvChild *child) { BlockDriverState *bs = child->opaque; - bdrv_do_drained_begin_quiesce(bs, NULL, false); + bdrv_do_drained_begin_quiesce(bs, NULL); } static bool bdrv_child_cb_drained_poll(BdrvChild *child) diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ static void bdrv_parent_cb_resize(BlockDriverState *bs); static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes, BdrvRequestFlags flags); -static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore, - bool ignore_bds_parents) +static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore) { BdrvChild *c, *next; QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) { - if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) { + if (c == ignore) { continue; } bdrv_parent_drained_begin_single(c, false); @@ -XXX,XX +XXX,XX @@ void bdrv_parent_drained_end_single(BdrvChild *c) } } -static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore, - bool ignore_bds_parents) +static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore) { BdrvChild *c; QLIST_FOREACH(c, &bs->parents, next_parent) { - if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) { + if (c == ignore) { continue; } bdrv_parent_drained_end_single(c); @@ -XXX,XX +XXX,XX @@ typedef struct { bool begin; bool poll; BdrvChild *parent; - bool ignore_bds_parents; } BdrvCoDrainData; /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */ @@ -XXX,XX +XXX,XX @@ static bool bdrv_drain_poll_top_level(BlockDriverState *bs, } static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, - bool ignore_bds_parents, bool poll); -static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent, - bool ignore_bds_parents); + bool poll); +static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent); static void bdrv_co_drain_bh_cb(void *opaque) { @@ -XXX,XX +XXX,XX @@ static void bdrv_co_drain_bh_cb(void *opaque) aio_context_acquire(ctx); bdrv_dec_in_flight(bs); if (data->begin) { - bdrv_do_drained_begin(bs, data->parent, data->ignore_bds_parents, - data->poll); + bdrv_do_drained_begin(bs, data->parent, data->poll); } else { assert(!data->poll); - bdrv_do_drained_end(bs, data->parent, data->ignore_bds_parents); + bdrv_do_drained_end(bs, data->parent); } aio_context_release(ctx); } else { @@ -XXX,XX +XXX,XX @@ static void bdrv_co_drain_bh_cb(void *opaque) static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, bool begin, BdrvChild *parent, - bool ignore_bds_parents, bool poll) { BdrvCoDrainData data; @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, .done = false, .begin = begin, .parent = parent, - .ignore_bds_parents = ignore_bds_parents, .poll = poll, }; @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, } } -void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, - BdrvChild *parent, bool ignore_bds_parents) +void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent) { IO_OR_GS_CODE(); assert(!qemu_in_coroutine()); @@ -XXX,XX +XXX,XX @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, /* Stop things in parent-to-child order */ if (qatomic_fetch_inc(&bs->quiesce_counter) == 0) { aio_disable_external(bdrv_get_aio_context(bs)); - - /* TODO Remove ignore_bds_parents, we don't consider it any more */ - bdrv_parent_drained_begin(bs, parent, false); + bdrv_parent_drained_begin(bs, parent); if (bs->drv && bs->drv->bdrv_drain_begin) { bs->drv->bdrv_drain_begin(bs); } @@ -XXX,XX +XXX,XX @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, } static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, - bool ignore_bds_parents, bool poll) + bool poll) { if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(bs, true, parent, ignore_bds_parents, poll); + bdrv_co_yield_to_drain(bs, true, parent, poll); return; } - bdrv_do_drained_begin_quiesce(bs, parent, ignore_bds_parents); + bdrv_do_drained_begin_quiesce(bs, parent); /* * Wait for drained requests to finish. @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, * nodes. */ if (poll) { - assert(!ignore_bds_parents); BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, parent)); } } @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, void bdrv_drained_begin(BlockDriverState *bs) { IO_OR_GS_CODE(); - bdrv_do_drained_begin(bs, NULL, false, true); + bdrv_do_drained_begin(bs, NULL, true); } /** * This function does not poll, nor must any of its recursively called * functions. */ -static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent, - bool ignore_bds_parents) +static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent) { int old_quiesce_counter; if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(bs, false, parent, ignore_bds_parents, false); + bdrv_co_yield_to_drain(bs, false, parent, false); return; } assert(bs->quiesce_counter > 0); @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent, if (bs->drv && bs->drv->bdrv_drain_end) { bs->drv->bdrv_drain_end(bs); } - /* TODO Remove ignore_bds_parents, we don't consider it any more */ - bdrv_parent_drained_end(bs, parent, false); - + bdrv_parent_drained_end(bs, parent); aio_enable_external(bdrv_get_aio_context(bs)); } } @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent, void bdrv_drained_end(BlockDriverState *bs) { IO_OR_GS_CODE(); - bdrv_do_drained_end(bs, NULL, false); + bdrv_do_drained_end(bs, NULL); } void bdrv_drain(BlockDriverState *bs) @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_begin(void) GLOBAL_STATE_CODE(); if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(NULL, true, NULL, true, true); + bdrv_co_yield_to_drain(NULL, true, NULL, true); return; } @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_begin(void) AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - bdrv_do_drained_begin(bs, NULL, true, false); + bdrv_do_drained_begin(bs, NULL, false); aio_context_release(aio_context); } @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_end_quiesce(BlockDriverState *bs) g_assert(!bs->refcnt); while (bs->quiesce_counter) { - bdrv_do_drained_end(bs, NULL, true); + bdrv_do_drained_end(bs, NULL); } } @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_end(void) AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - bdrv_do_drained_end(bs, NULL, true); + bdrv_do_drained_end(bs, NULL); aio_context_release(aio_context); } -- 2.38.1 The next patch adds a parent drain to bdrv_attach_child_common(), which shouldn't be, but is currently called from coroutines in some cases (e.g. .bdrv_co_create implementations generally open new nodes). Therefore, the assertion that we're not in a coroutine doesn't hold true any more. We could just remove the assertion because there is nothing in the function that should be in conflict with running in a coroutine, but just to be on the safe side, we can reverse the caller relationship between bdrv_do_drained_begin() and bdrv_do_drained_begin_quiesce() so that the latter also just drops out of coroutine context and we can still be certain in the future that any drain code doesn't run in coroutines. As a nice side effect, the structure of bdrv_do_drained_begin() is now symmetrical with bdrv_do_drained_end(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221118174110.55183-14-kwolf@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/io.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, } } -void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent) +static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, + bool poll) { IO_OR_GS_CODE(); - assert(!qemu_in_coroutine()); + + if (qemu_in_coroutine()) { + bdrv_co_yield_to_drain(bs, true, parent, poll); + return; + } /* Stop things in parent-to-child order */ if (qatomic_fetch_inc(&bs->quiesce_counter) == 0) { @@ -XXX,XX +XXX,XX @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent) bs->drv->bdrv_drain_begin(bs); } } -} - -static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, - bool poll) -{ - if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(bs, true, parent, poll); - return; - } - - bdrv_do_drained_begin_quiesce(bs, parent); /* * Wait for drained requests to finish. @@ -XXX,XX +XXX,XX @@ static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, } } +void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent) +{ + bdrv_do_drained_begin(bs, parent, false); +} + void bdrv_drained_begin(BlockDriverState *bs) { IO_OR_GS_CODE(); -- 2.38.1 In order to make sure that bdrv_replace_child_noperm() doesn't have to poll any more, get rid of the bdrv_parent_drained_begin_single() call. This is possible now because we can require that the parent is already drained through the child in question when the function is called and we don't call the parent drain callbacks more than once. The additional drain calls needed in callers cause the test case to run its code in the drain handler too early (bdrv_attach_child() drains now), so modify it to only enable the code after the test setup has completed. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221118174110.55183-15-kwolf@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-io.h | 8 +++ block.c | 103 ++++++++++++++++++++++++++++++----- block/io.c | 2 +- tests/unit/test-bdrv-drain.c | 10 ++++ 4 files changed, 108 insertions(+), 15 deletions(-) diff --git a/include/block/block-io.h b/include/block/block-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -XXX,XX +XXX,XX @@ bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); */ void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll); +/** + * bdrv_parent_drained_poll_single: + * + * Returns true if there is any pending activity to cease before @c can be + * called quiesced, false otherwise. + */ +bool bdrv_parent_drained_poll_single(BdrvChild *c); + /** * bdrv_parent_drained_end_single: * diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_abort(void *opaque) GLOBAL_STATE_CODE(); /* old_bs reference is transparently moved from @s to @s->child */ + if (!s->child->bs) { + /* + * The parents were undrained when removing old_bs from the child. New + * requests can't have been made, though, because the child was empty. + * + * TODO Make bdrv_replace_child_noperm() transactionable to avoid + * undraining the parent in the first place. Once this is done, having + * new_bs drained when calling bdrv_replace_child_tran() is not a + * requirement any more. + */ + bdrv_parent_drained_begin_single(s->child, false); + assert(!bdrv_parent_drained_poll_single(s->child)); + } + assert(s->child->quiesced_parent); bdrv_replace_child_noperm(s->child, s->old_bs); bdrv_unref(new_bs); } @@ -XXX,XX +XXX,XX @@ static TransactionActionDrv bdrv_replace_child_drv = { * * Note: real unref of old_bs is done only on commit. * + * Both @child->bs and @new_bs (if non-NULL) must be drained. @new_bs must be + * kept drained until the transaction is completed. + * * The function doesn't update permissions, caller is responsible for this. */ static void bdrv_replace_child_tran(BdrvChild *child, BlockDriverState *new_bs, Transaction *tran) { BdrvReplaceChildState *s = g_new(BdrvReplaceChildState, 1); + + assert(child->quiesced_parent); + assert(!new_bs || new_bs->quiesce_counter); + *s = (BdrvReplaceChildState) { .child = child, .old_bs = child->bs, @@ -XXX,XX +XXX,XX @@ uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm) return permissions[qapi_perm]; } +/* + * Replaces the node that a BdrvChild points to without updating permissions. + * + * If @new_bs is non-NULL, the parent of @child must already be drained through + * @child. + * + * This function does not poll. + */ static void bdrv_replace_child_noperm(BdrvChild *child, BlockDriverState *new_bs) { @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, int new_bs_quiesce_counter; assert(!child->frozen); + + /* + * If we want to change the BdrvChild to point to a drained node as its new + * child->bs, we need to make sure that its new parent is drained, too. In + * other words, either child->quiesce_parent must already be true or we must + * be able to set it and keep the parent's quiesce_counter consistent with + * that, but without polling or starting new requests (this function + * guarantees that it doesn't poll, and starting new requests would be + * against the invariants of drain sections). + * + * To keep things simple, we pick the first option (child->quiesce_parent + * must already be true). We also generalise the rule a bit to make it + * easier to verify in callers and more likely to be covered in test cases: + * The parent must be quiesced through this child even if new_bs isn't + * currently drained. + * + * The only exception is for callers that always pass new_bs == NULL. In + * this case, we obviously never need to consider the case of a drained + * new_bs, so we can keep the callers simpler by allowing them not to drain + * the parent. + */ + assert(!new_bs || child->quiesced_parent); assert(old_bs != new_bs); GLOBAL_STATE_CODE(); @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs)); } - /* - * If the new child node is drained but the old one was not, flush - * all outstanding requests to the old child node. - */ - new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0); - if (new_bs_quiesce_counter && !child->quiesced_parent) { - bdrv_parent_drained_begin_single(child, true); - } - if (old_bs) { if (child->klass->detach) { child->klass->detach(child); @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, } /* - * If the old child node was drained but the new one is not, allow - * requests to come in only after the new node has been attached. - * - * Update new_bs_quiesce_counter because bdrv_parent_drained_begin_single() - * polls, which could have changed the value. + * If the parent was drained through this BdrvChild previously, but new_bs + * is not drained, allow requests to come in only after the new node has + * been attached. */ new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0); if (!new_bs_quiesce_counter && child->quiesced_parent) { @@ -XXX,XX +XXX,XX @@ static BdrvChild *bdrv_attach_child_common(BlockDriverState *child_bs, } bdrv_ref(child_bs); + /* + * Let every new BdrvChild start with a drained parent. Inserting the child + * in the graph with bdrv_replace_child_noperm() will undrain it if + * @child_bs is not drained. + * + * The child was only just created and is not yet visible in global state + * until bdrv_replace_child_noperm() inserts it into the graph, so nobody + * could have sent requests and polling is not necessary. + * + * Note that this means that the parent isn't fully drained yet, we only + * stop new requests from coming in. This is fine, we don't care about the + * old requests here, they are not for this child. If another place enters a + * drain section for the same parent, but wants it to be fully quiesced, it + * will not run most of the the code in .drained_begin() again (which is not + * a problem, we already did this), but it will still poll until the parent + * is fully quiesced, so it will not be negatively affected either. + */ + bdrv_parent_drained_begin_single(new_child, false); bdrv_replace_child_noperm(new_child, child_bs); BdrvAttachChildCommonState *s = g_new(BdrvAttachChildCommonState, 1); @@ -XXX,XX +XXX,XX @@ static void bdrv_remove_child(BdrvChild *child, Transaction *tran) } if (child->bs) { + BlockDriverState *bs = child->bs; + bdrv_drained_begin(bs); bdrv_replace_child_tran(child, NULL, tran); + bdrv_drained_end(bs); } tran_add(tran, &bdrv_remove_child_drv, child); } +static void undrain_on_clean_cb(void *opaque) +{ + bdrv_drained_end(opaque); +} + +static TransactionActionDrv undrain_on_clean = { + .clean = undrain_on_clean_cb, +}; + static int bdrv_replace_node_noperm(BlockDriverState *from, BlockDriverState *to, bool auto_skip, Transaction *tran, @@ -XXX,XX +XXX,XX @@ static int bdrv_replace_node_noperm(BlockDriverState *from, GLOBAL_STATE_CODE(); + bdrv_drained_begin(from); + bdrv_drained_begin(to); + tran_add(tran, &undrain_on_clean, from); + tran_add(tran, &undrain_on_clean, to); + QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) { assert(c->bs == from); if (!should_update_child(c, to)) { diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore) } } -static bool bdrv_parent_drained_poll_single(BdrvChild *c) +bool bdrv_parent_drained_poll_single(BdrvChild *c) { if (c->klass->drained_poll) { return c->klass->drained_poll(c); diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-drain.c +++ b/tests/unit/test-bdrv-drain.c @@ -XXX,XX +XXX,XX @@ static void test_drop_intermediate_poll(void) typedef struct BDRVReplaceTestState { + bool setup_completed; bool was_drained; bool was_undrained; bool has_read; @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_test_drain_begin(BlockDriverState *bs) { BDRVReplaceTestState *s = bs->opaque; + if (!s->setup_completed) { + return; + } + if (!s->drain_count) { s->drain_co = qemu_coroutine_create(bdrv_replace_test_drain_co, bs); bdrv_inc_in_flight(bs); @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_test_drain_end(BlockDriverState *bs) { BDRVReplaceTestState *s = bs->opaque; + if (!s->setup_completed) { + return; + } + g_assert(s->drain_count > 0); if (!--s->drain_count) { s->was_undrained = true; @@ -XXX,XX +XXX,XX @@ static void do_test_replace_child_mid_drain(int old_drain_count, bdrv_ref(old_child_bs); bdrv_attach_child(parent_bs, old_child_bs, "child", &child_of_bds, BDRV_CHILD_COW, &error_abort); + parent_s->setup_completed = true; for (i = 0; i < old_drain_count; i++) { bdrv_drained_begin(old_child_bs); -- 2.38.1 All callers of bdrv_parent_drained_begin_single() pass poll=false now, so we don't need the parameter any more. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221118174110.55183-16-kwolf@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-io.h | 5 ++--- block.c | 4 ++-- block/io.c | 8 ++------ 3 files changed, 6 insertions(+), 11 deletions(-) diff --git a/include/block/block-io.h b/include/block/block-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -XXX,XX +XXX,XX @@ bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); /** * bdrv_parent_drained_begin_single: * - * Begin a quiesced section for the parent of @c. If @poll is true, wait for - * any pending activity to cease. + * Begin a quiesced section for the parent of @c. */ -void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll); +void bdrv_parent_drained_begin_single(BdrvChild *c); /** * bdrv_parent_drained_poll_single: diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_abort(void *opaque) * new_bs drained when calling bdrv_replace_child_tran() is not a * requirement any more. */ - bdrv_parent_drained_begin_single(s->child, false); + bdrv_parent_drained_begin_single(s->child); assert(!bdrv_parent_drained_poll_single(s->child)); } assert(s->child->quiesced_parent); @@ -XXX,XX +XXX,XX @@ static BdrvChild *bdrv_attach_child_common(BlockDriverState *child_bs, * a problem, we already did this), but it will still poll until the parent * is fully quiesced, so it will not be negatively affected either. */ - bdrv_parent_drained_begin_single(new_child, false); + bdrv_parent_drained_begin_single(new_child); bdrv_replace_child_noperm(new_child, child_bs); BdrvAttachChildCommonState *s = g_new(BdrvAttachChildCommonState, 1); diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore) if (c == ignore) { continue; } - bdrv_parent_drained_begin_single(c, false); + bdrv_parent_drained_begin_single(c); } } @@ -XXX,XX +XXX,XX @@ static bool bdrv_parent_drained_poll(BlockDriverState *bs, BdrvChild *ignore, return busy; } -void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll) +void bdrv_parent_drained_begin_single(BdrvChild *c) { - AioContext *ctx = bdrv_child_get_parent_aio_context(c); IO_OR_GS_CODE(); assert(!c->quiesced_parent); @@ -XXX,XX +XXX,XX @@ void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll) if (c->klass->drained_begin) { c->klass->drained_begin(c); } - if (poll) { - AIO_WAIT_WHILE(ctx, bdrv_parent_drained_poll_single(c)); - } } static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> bdrv_common_block_status_above() is a g_c_w, and it is being called by many "wrapper" functions like bdrv_is_allocated(), bdrv_is_allocated_above() and bdrv_block_status_above(). Because we want to eventually split the coroutine from non-coroutine case in g_c_w, create duplicate wrappers that take care of directly calling the same coroutine functions called in the g_c_w. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-2-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-io.h | 15 +++++++++++ block/io.c | 58 +++++++++++++++++++++++++++++++++++++--- 2 files changed, 70 insertions(+), 3 deletions(-) diff --git a/include/block/block-io.h b/include/block/block-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -XXX,XX +XXX,XX @@ bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs); int bdrv_block_status(BlockDriverState *bs, int64_t offset, int64_t bytes, int64_t *pnum, int64_t *map, BlockDriverState **file); + +int coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs, + BlockDriverState *base, + int64_t offset, int64_t bytes, + int64_t *pnum, int64_t *map, + BlockDriverState **file); int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base, int64_t offset, int64_t bytes, int64_t *pnum, int64_t *map, BlockDriverState **file); + +int coroutine_fn bdrv_co_is_allocated(BlockDriverState *bs, int64_t offset, + int64_t bytes, int64_t *pnum); int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes, int64_t *pnum); + +int coroutine_fn bdrv_co_is_allocated_above(BlockDriverState *top, + BlockDriverState *base, + bool include_base, int64_t offset, + int64_t bytes, int64_t *pnum); int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base, bool include_base, int64_t offset, int64_t bytes, int64_t *pnum); + int coroutine_fn bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset, int64_t bytes); diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs, return ret; } +int coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs, + BlockDriverState *base, + int64_t offset, int64_t bytes, + int64_t *pnum, int64_t *map, + BlockDriverState **file) +{ + IO_CODE(); + return bdrv_co_common_block_status_above(bs, base, false, true, offset, + bytes, pnum, map, file, NULL); +} + int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base, int64_t offset, int64_t bytes, int64_t *pnum, int64_t *map, BlockDriverState **file) @@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset, return (pnum == bytes) && (ret & BDRV_BLOCK_ZERO); } +int coroutine_fn bdrv_co_is_allocated(BlockDriverState *bs, int64_t offset, + int64_t bytes, int64_t *pnum) +{ + int ret; + int64_t dummy; + IO_CODE(); + + ret = bdrv_co_common_block_status_above(bs, bs, true, false, offset, + bytes, pnum ? pnum : &dummy, NULL, + NULL, NULL); + if (ret < 0) { + return ret; + } + return !!(ret & BDRV_BLOCK_ALLOCATED); +} + int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes, int64_t *pnum) { @@ -XXX,XX +XXX,XX @@ int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes, return !!(ret & BDRV_BLOCK_ALLOCATED); } +/* See bdrv_is_allocated_above for documentation */ +int coroutine_fn bdrv_co_is_allocated_above(BlockDriverState *top, + BlockDriverState *base, + bool include_base, int64_t offset, + int64_t bytes, int64_t *pnum) +{ + int depth; + int ret; + IO_CODE(); + + ret = bdrv_co_common_block_status_above(top, base, include_base, false, + offset, bytes, pnum, NULL, NULL, + &depth); + if (ret < 0) { + return ret; + } + + if (ret & BDRV_BLOCK_ALLOCATED) { + return depth; + } + return 0; +} + /* * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] * @@ -XXX,XX +XXX,XX @@ int bdrv_is_allocated_above(BlockDriverState *top, int64_t bytes, int64_t *pnum) { int depth; - int ret = bdrv_common_block_status_above(top, base, include_base, false, - offset, bytes, pnum, NULL, NULL, - &depth); + int ret; IO_CODE(); + + ret = bdrv_common_block_status_above(top, base, include_base, false, + offset, bytes, pnum, NULL, NULL, + &depth); if (ret < 0) { return ret; } -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> These functions end up calling bdrv_common_block_status_above(), a generated_co_wrapper function. In addition, they also happen to be always called in coroutine context, meaning all callers are coroutine_fn. This means that the g_c_w function will enter the qemu_in_coroutine() case and eventually suspend (or in other words call qemu_coroutine_yield()). Therefore we can mark such functions coroutine_fn too. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-3-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-copy.h | 5 +++-- block/block-copy.c | 21 ++++++++++++--------- 2 files changed, 15 insertions(+), 11 deletions(-) diff --git a/include/block/block-copy.h b/include/block/block-copy.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-copy.h +++ b/include/block/block-copy.h @@ -XXX,XX +XXX,XX @@ void block_copy_set_progress_meter(BlockCopyState *s, ProgressMeter *pm); void block_copy_state_free(BlockCopyState *s); void block_copy_reset(BlockCopyState *s, int64_t offset, int64_t bytes); -int64_t block_copy_reset_unallocated(BlockCopyState *s, - int64_t offset, int64_t *count); +int64_t coroutine_fn block_copy_reset_unallocated(BlockCopyState *s, + int64_t offset, + int64_t *count); int coroutine_fn block_copy(BlockCopyState *s, int64_t offset, int64_t bytes, bool ignore_ratelimit, uint64_t timeout_ns, diff --git a/block/block-copy.c b/block/block-copy.c index XXXXXXX..XXXXXXX 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -XXX,XX +XXX,XX @@ static coroutine_fn int block_copy_task_entry(AioTask *task) return ret; } -static int block_copy_block_status(BlockCopyState *s, int64_t offset, - int64_t bytes, int64_t *pnum) +static coroutine_fn int block_copy_block_status(BlockCopyState *s, + int64_t offset, + int64_t bytes, int64_t *pnum) { int64_t num; BlockDriverState *base; @@ -XXX,XX +XXX,XX @@ static int block_copy_block_status(BlockCopyState *s, int64_t offset, base = NULL; } - ret = bdrv_block_status_above(s->source->bs, base, offset, bytes, &num, - NULL, NULL); + ret = bdrv_co_block_status_above(s->source->bs, base, offset, bytes, &num, + NULL, NULL); if (ret < 0 || num < s->cluster_size) { /* * On error or if failed to obtain large enough chunk just fallback to @@ -XXX,XX +XXX,XX @@ static int block_copy_block_status(BlockCopyState *s, int64_t offset, * Check if the cluster starting at offset is allocated or not. * return via pnum the number of contiguous clusters sharing this allocation. */ -static int block_copy_is_cluster_allocated(BlockCopyState *s, int64_t offset, - int64_t *pnum) +static int coroutine_fn block_copy_is_cluster_allocated(BlockCopyState *s, + int64_t offset, + int64_t *pnum) { BlockDriverState *bs = s->source->bs; int64_t count, total_count = 0; @@ -XXX,XX +XXX,XX @@ static int block_copy_is_cluster_allocated(BlockCopyState *s, int64_t offset, assert(QEMU_IS_ALIGNED(offset, s->cluster_size)); while (true) { - ret = bdrv_is_allocated(bs, offset, bytes, &count); + ret = bdrv_co_is_allocated(bs, offset, bytes, &count); if (ret < 0) { return ret; } @@ -XXX,XX +XXX,XX @@ void block_copy_reset(BlockCopyState *s, int64_t offset, int64_t bytes) * @return 0 when the cluster at @offset was unallocated, * 1 otherwise, and -ret on error. */ -int64_t block_copy_reset_unallocated(BlockCopyState *s, - int64_t offset, int64_t *count) +int64_t coroutine_fn block_copy_reset_unallocated(BlockCopyState *s, + int64_t offset, + int64_t *count) { int ret; int64_t clusters, bytes; -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> These functions end up calling bdrv_*() implemented as generated_co_wrapper functions. In addition, they also happen to be always called in coroutine context, meaning all callers are coroutine_fn. This means that the g_c_w function will enter the qemu_in_coroutine() case and eventually suspend (or in other words call qemu_coroutine_yield()). Therefore we can mark such functions coroutine_fn too. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-4-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- nbd/server.c | 29 ++++++++++++++++------------- 1 file changed, 16 insertions(+), 13 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index XXXXXXX..XXXXXXX 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -XXX,XX +XXX,XX @@ static int nbd_extent_array_add(NBDExtentArray *ea, return 0; } -static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, - uint64_t bytes, NBDExtentArray *ea) +static int coroutine_fn blockstatus_to_extents(BlockDriverState *bs, + uint64_t offset, uint64_t bytes, + NBDExtentArray *ea) { while (bytes) { uint32_t flags; int64_t num; - int ret = bdrv_block_status_above(bs, NULL, offset, bytes, &num, - NULL, NULL); + int ret = bdrv_co_block_status_above(bs, NULL, offset, bytes, &num, + NULL, NULL); if (ret < 0) { return ret; @@ -XXX,XX +XXX,XX @@ static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, return 0; } -static int blockalloc_to_extents(BlockDriverState *bs, uint64_t offset, - uint64_t bytes, NBDExtentArray *ea) +static int coroutine_fn blockalloc_to_extents(BlockDriverState *bs, + uint64_t offset, uint64_t bytes, + NBDExtentArray *ea) { while (bytes) { int64_t num; - int ret = bdrv_is_allocated_above(bs, NULL, false, offset, bytes, - &num); + int ret = bdrv_co_is_allocated_above(bs, NULL, false, offset, bytes, + &num); if (ret < 0) { return ret; @@ -XXX,XX +XXX,XX @@ static int nbd_co_send_extents(NBDClient *client, uint64_t handle, } /* Get block status from the exported device and send it to the client */ -static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, - BlockDriverState *bs, uint64_t offset, - uint32_t length, bool dont_fragment, - bool last, uint32_t context_id, - Error **errp) +static int +coroutine_fn nbd_co_send_block_status(NBDClient *client, uint64_t handle, + BlockDriverState *bs, uint64_t offset, + uint32_t length, bool dont_fragment, + bool last, uint32_t context_id, + Error **errp) { int ret; unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> Avoid mixing bdrv_* functions with blk_*, so create blk_* counterparts for bdrv_block_status_above and bdrv_is_allocated_above. Note that since blk_co_block_status_above only calls the g_c_w function bdrv_common_block_status_above and is marked as coroutine_fn, call directly bdrv_co_common_block_status_above() to avoid using a g_c_w. Same applies to blk_co_is_allocated_above. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-5-eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/sysemu/block-backend-io.h | 9 +++++++++ block/block-backend.c | 21 ++++++++++++++++++++ block/commit.c | 4 ++-- nbd/server.c | 32 +++++++++++++++---------------- 4 files changed, 48 insertions(+), 18 deletions(-) diff --git a/include/sysemu/block-backend-io.h b/include/sysemu/block-backend-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/sysemu/block-backend-io.h +++ b/include/sysemu/block-backend-io.h @@ -XXX,XX +XXX,XX @@ int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in, int64_t bytes, BdrvRequestFlags read_flags, BdrvRequestFlags write_flags); +int coroutine_fn blk_co_block_status_above(BlockBackend *blk, + BlockDriverState *base, + int64_t offset, int64_t bytes, + int64_t *pnum, int64_t *map, + BlockDriverState **file); +int coroutine_fn blk_co_is_allocated_above(BlockBackend *blk, + BlockDriverState *base, + bool include_base, int64_t offset, + int64_t bytes, int64_t *pnum); /* * "I/O or GS" API functions. These functions can run without diff --git a/block/block-backend.c b/block/block-backend.c index XXXXXXX..XXXXXXX 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -XXX,XX +XXX,XX @@ int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset, return blk_co_pwritev_part(blk, offset, bytes, qiov, 0, flags); } +int coroutine_fn blk_co_block_status_above(BlockBackend *blk, + BlockDriverState *base, + int64_t offset, int64_t bytes, + int64_t *pnum, int64_t *map, + BlockDriverState **file) +{ + IO_CODE(); + return bdrv_co_block_status_above(blk_bs(blk), base, offset, bytes, pnum, + map, file); +} + +int coroutine_fn blk_co_is_allocated_above(BlockBackend *blk, + BlockDriverState *base, + bool include_base, int64_t offset, + int64_t bytes, int64_t *pnum) +{ + IO_CODE(); + return bdrv_co_is_allocated_above(blk_bs(blk), base, include_base, offset, + bytes, pnum); +} + typedef struct BlkRwCo { BlockBackend *blk; int64_t offset; diff --git a/block/commit.c b/block/commit.c index XXXXXXX..XXXXXXX 100644 --- a/block/commit.c +++ b/block/commit.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn commit_run(Job *job, Error **errp) break; } /* Copy if allocated above the base */ - ret = bdrv_is_allocated_above(blk_bs(s->top), s->base_overlay, true, - offset, COMMIT_BUFFER_SIZE, &n); + ret = blk_co_is_allocated_above(s->top, s->base_overlay, true, + offset, COMMIT_BUFFER_SIZE, &n); copy = (ret > 0); trace_commit_one_iteration(s, offset, n, ret); if (copy) { diff --git a/nbd/server.c b/nbd/server.c index XXXXXXX..XXXXXXX 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, } /* Do a sparse read and send the structured reply to the client. - * Returns -errno if sending fails. bdrv_block_status_above() failure is + * Returns -errno if sending fails. blk_co_block_status_above() failure is * reported to the client, at which point this function succeeds. */ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, @@ -XXX,XX +XXX,XX @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, while (progress < size) { int64_t pnum; - int status = bdrv_block_status_above(blk_bs(exp->common.blk), NULL, - offset + progress, - size - progress, &pnum, NULL, - NULL); + int status = blk_co_block_status_above(exp->common.blk, NULL, + offset + progress, + size - progress, &pnum, NULL, + NULL); bool final; if (status < 0) { @@ -XXX,XX +XXX,XX @@ static int nbd_extent_array_add(NBDExtentArray *ea, return 0; } -static int coroutine_fn blockstatus_to_extents(BlockDriverState *bs, +static int coroutine_fn blockstatus_to_extents(BlockBackend *blk, uint64_t offset, uint64_t bytes, NBDExtentArray *ea) { while (bytes) { uint32_t flags; int64_t num; - int ret = bdrv_co_block_status_above(bs, NULL, offset, bytes, &num, - NULL, NULL); + int ret = blk_co_block_status_above(blk, NULL, offset, bytes, &num, + NULL, NULL); if (ret < 0) { return ret; @@ -XXX,XX +XXX,XX @@ static int coroutine_fn blockstatus_to_extents(BlockDriverState *bs, return 0; } -static int coroutine_fn blockalloc_to_extents(BlockDriverState *bs, +static int coroutine_fn blockalloc_to_extents(BlockBackend *blk, uint64_t offset, uint64_t bytes, NBDExtentArray *ea) { while (bytes) { int64_t num; - int ret = bdrv_co_is_allocated_above(bs, NULL, false, offset, bytes, - &num); + int ret = blk_co_is_allocated_above(blk, NULL, false, offset, bytes, + &num); if (ret < 0) { return ret; @@ -XXX,XX +XXX,XX @@ static int nbd_co_send_extents(NBDClient *client, uint64_t handle, /* Get block status from the exported device and send it to the client */ static int coroutine_fn nbd_co_send_block_status(NBDClient *client, uint64_t handle, - BlockDriverState *bs, uint64_t offset, + BlockBackend *blk, uint64_t offset, uint32_t length, bool dont_fragment, bool last, uint32_t context_id, Error **errp) @@ -XXX,XX +XXX,XX @@ coroutine_fn nbd_co_send_block_status(NBDClient *client, uint64_t handle, g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents); if (context_id == NBD_META_ID_BASE_ALLOCATION) { - ret = blockstatus_to_extents(bs, offset, length, ea); + ret = blockstatus_to_extents(blk, offset, length, ea); } else { - ret = blockalloc_to_extents(bs, offset, length, ea); + ret = blockalloc_to_extents(blk, offset, length, ea); } if (ret < 0) { return nbd_co_send_structured_error( @@ -XXX,XX +XXX,XX @@ static coroutine_fn int nbd_handle_request(NBDClient *client, if (client->export_meta.base_allocation) { ret = nbd_co_send_block_status(client, request->handle, - blk_bs(exp->common.blk), + exp->common.blk, request->from, request->len, dont_fragment, !--contexts_remaining, @@ -XXX,XX +XXX,XX @@ static coroutine_fn int nbd_handle_request(NBDClient *client, if (client->export_meta.allocation_depth) { ret = nbd_co_send_block_status(client, request->handle, - blk_bs(exp->common.blk), + exp->common.blk, request->from, request->len, dont_fragment, !--contexts_remaining, -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> These functions end up calling bdrv_create() implemented as generated_co_wrapper functions. In addition, they also happen to be always called in coroutine context, meaning all callers are coroutine_fn. This means that the g_c_w function will enter the qemu_in_coroutine() case and eventually suspend (or in other words call qemu_coroutine_yield()). Therefore we can mark such functions coroutine_fn too. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-6-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/vmdk.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/block/vmdk.c b/block/vmdk.c index XXXXXXX..XXXXXXX 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -XXX,XX +XXX,XX @@ exit: return ret; } -static int vmdk_create_extent(const char *filename, int64_t filesize, - bool flat, bool compress, bool zeroed_grain, - BlockBackend **pbb, - QemuOpts *opts, Error **errp) +static int coroutine_fn vmdk_create_extent(const char *filename, + int64_t filesize, bool flat, + bool compress, bool zeroed_grain, + BlockBackend **pbb, + QemuOpts *opts, Error **errp) { int ret; BlockBackend *blk = NULL; @@ -XXX,XX +XXX,XX @@ static int filename_decompose(const char *filename, char *path, char *prefix, * non-split format. * idx >= 1: get the n-th extent if in a split subformat */ -typedef BlockBackend *(*vmdk_create_extent_fn)(int64_t size, - int idx, - bool flat, - bool split, - bool compress, - bool zeroed_grain, - void *opaque, - Error **errp); +typedef BlockBackend * coroutine_fn (*vmdk_create_extent_fn)(int64_t size, + int idx, + bool flat, + bool split, + bool compress, + bool zeroed_grain, + void *opaque, + Error **errp); static void vmdk_desc_add_extent(GString *desc, const char *extent_line_fmt, @@ -XXX,XX +XXX,XX @@ typedef struct { QemuOpts *opts; } VMDKCreateOptsData; -static BlockBackend *vmdk_co_create_opts_cb(int64_t size, int idx, +static BlockBackend * coroutine_fn vmdk_co_create_opts_cb(int64_t size, int idx, bool flat, bool split, bool compress, bool zeroed_grain, void *opaque, Error **errp) @@ -XXX,XX +XXX,XX @@ exit: return ret; } -static BlockBackend *vmdk_co_create_cb(int64_t size, int idx, - bool flat, bool split, bool compress, - bool zeroed_grain, void *opaque, - Error **errp) +static BlockBackend * coroutine_fn vmdk_co_create_cb(int64_t size, int idx, + bool flat, bool split, + bool compress, + bool zeroed_grain, + void *opaque, Error **errp) { int ret; BlockDriverState *bs; -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> We know that the string will stay around until the function returns, and the parameter of drv->bdrv_co_create_opts is const char*, so it must not be modified either. Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-7-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ int bdrv_create(BlockDriver *drv, const char* filename, Coroutine *co; CreateCo cco = { .drv = drv, - .filename = g_strdup(filename), + .filename = filename, .opts = opts, .ret = NOT_DONE, .err = NULL, @@ -XXX,XX +XXX,XX @@ int bdrv_create(BlockDriver *drv, const char* filename, if (!drv->bdrv_co_create_opts) { error_setg(errp, "Driver '%s' does not support image creation", drv->format_name); - ret = -ENOTSUP; - goto out; + return -ENOTSUP; } if (qemu_in_coroutine()) { @@ -XXX,XX +XXX,XX @@ int bdrv_create(BlockDriver *drv, const char* filename, } } -out: - g_free(cco.filename); return ret; } -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> Call two different functions depending on whether bdrv_create is in coroutine or not, following the same pattern as generated_co_wrapper functions. This allows to also call the coroutine function directly, without using CreateCo or relying in bdrv_create(). Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-8-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 69 ++++++++++++++++++++++++++++----------------------------- 1 file changed, 34 insertions(+), 35 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ typedef struct CreateCo { Error *err; } CreateCo; -static void coroutine_fn bdrv_create_co_entry(void *opaque) +static int coroutine_fn bdrv_co_create(BlockDriver *drv, const char *filename, + QemuOpts *opts, Error **errp) { - Error *local_err = NULL; int ret; + GLOBAL_STATE_CODE(); + ERRP_GUARD(); + if (!drv->bdrv_co_create_opts) { + error_setg(errp, "Driver '%s' does not support image creation", + drv->format_name); + return -ENOTSUP; + } + + ret = drv->bdrv_co_create_opts(drv, filename, opts, errp); + if (ret < 0 && !*errp) { + error_setg_errno(errp, -ret, "Could not create image"); + } + + return ret; +} + +static void coroutine_fn bdrv_create_co_entry(void *opaque) +{ CreateCo *cco = opaque; - assert(cco->drv); GLOBAL_STATE_CODE(); - ret = cco->drv->bdrv_co_create_opts(cco->drv, - cco->filename, cco->opts, &local_err); - error_propagate(&cco->err, local_err); - cco->ret = ret; + cco->ret = bdrv_co_create(cco->drv, cco->filename, cco->opts, &cco->err); + aio_wait_kick(); } int bdrv_create(BlockDriver *drv, const char* filename, QemuOpts *opts, Error **errp) { - int ret; - GLOBAL_STATE_CODE(); - Coroutine *co; - CreateCo cco = { - .drv = drv, - .filename = filename, - .opts = opts, - .ret = NOT_DONE, - .err = NULL, - }; - - if (!drv->bdrv_co_create_opts) { - error_setg(errp, "Driver '%s' does not support image creation", drv->format_name); - return -ENOTSUP; - } - if (qemu_in_coroutine()) { /* Fast-path if already in coroutine context */ - bdrv_create_co_entry(&cco); + return bdrv_co_create(drv, filename, opts, errp); } else { + Coroutine *co; + CreateCo cco = { + .drv = drv, + .filename = filename, + .opts = opts, + .ret = NOT_DONE, + .err = NULL, + }; + co = qemu_coroutine_create(bdrv_create_co_entry, &cco); qemu_coroutine_enter(co); while (cco.ret == NOT_DONE) { aio_poll(qemu_get_aio_context(), true); } + error_propagate(errp, cco.err); + return cco.ret; } - - ret = cco.ret; - if (ret < 0) { - if (cco.err) { - error_propagate(errp, cco.err); - } else { - error_setg_errno(errp, -ret, "Could not create image"); - } - } - - return ret; } /** -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> It is always called in coroutine_fn callbacks, therefore it can directly call bdrv_co_create(). Rename it to bdrv_co_create_file too. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-9-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-global-state.h | 3 ++- block.c | 5 +++-- block/crypto.c | 2 +- block/parallels.c | 2 +- block/qcow.c | 2 +- block/qcow2.c | 4 ++-- block/qed.c | 2 +- block/raw-format.c | 2 +- block/vdi.c | 2 +- block/vhdx.c | 2 +- block/vmdk.c | 2 +- block/vpc.c | 2 +- 12 files changed, 16 insertions(+), 14 deletions(-) diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -XXX,XX +XXX,XX @@ BlockDriver *bdrv_find_protocol(const char *filename, BlockDriver *bdrv_find_format(const char *format_name); int bdrv_create(BlockDriver *drv, const char* filename, QemuOpts *opts, Error **errp); -int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp); +int coroutine_fn bdrv_co_create_file(const char *filename, QemuOpts *opts, + Error **errp); BlockDriverState *bdrv_new(void); int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top, diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ out: return ret; } -int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp) +int coroutine_fn bdrv_co_create_file(const char *filename, QemuOpts *opts, + Error **errp) { QemuOpts *protocol_opts; BlockDriver *drv; @@ -XXX,XX +XXX,XX @@ int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp) goto out; } - ret = bdrv_create(drv, filename, protocol_opts, errp); + ret = bdrv_co_create(drv, filename, protocol_opts, errp); out: qemu_opts_del(protocol_opts); qobject_unref(qdict); diff --git a/block/crypto.c b/block/crypto.c index XXXXXXX..XXXXXXX 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn block_crypto_co_create_opts_luks(BlockDriver *drv, } /* Create protocol layer */ - ret = bdrv_create_file(filename, opts, errp); + ret = bdrv_co_create_file(filename, opts, errp); if (ret < 0) { goto fail; } diff --git a/block/parallels.c b/block/parallels.c index XXXXXXX..XXXXXXX 100644 --- a/block/parallels.c +++ b/block/parallels.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn parallels_co_create_opts(BlockDriver *drv, } /* Create and open the file (protocol layer) */ - ret = bdrv_create_file(filename, opts, errp); + ret = bdrv_co_create_file(filename, opts, errp); if (ret < 0) { goto done; } diff --git a/block/qcow.c b/block/qcow.c index XXXXXXX..XXXXXXX 100644 --- a/block/qcow.c +++ b/block/qcow.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn qcow_co_create_opts(BlockDriver *drv, } /* Create and open the file (protocol layer) */ - ret = bdrv_create_file(filename, opts, errp); + ret = bdrv_co_create_file(filename, opts, errp); if (ret < 0) { goto fail; } diff --git a/block/qcow2.c b/block/qcow2.c index XXXXXXX..XXXXXXX 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn qcow2_co_create_opts(BlockDriver *drv, } /* Create and open the file (protocol layer) */ - ret = bdrv_create_file(filename, opts, errp); + ret = bdrv_co_create_file(filename, opts, errp); if (ret < 0) { goto finish; } @@ -XXX,XX +XXX,XX @@ static int coroutine_fn qcow2_co_create_opts(BlockDriver *drv, /* Create and open an external data file (protocol layer) */ val = qdict_get_try_str(qdict, BLOCK_OPT_DATA_FILE); if (val) { - ret = bdrv_create_file(val, opts, errp); + ret = bdrv_co_create_file(val, opts, errp); if (ret < 0) { goto finish; } diff --git a/block/qed.c b/block/qed.c index XXXXXXX..XXXXXXX 100644 --- a/block/qed.c +++ b/block/qed.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_qed_co_create_opts(BlockDriver *drv, } /* Create and open the file (protocol layer) */ - ret = bdrv_create_file(filename, opts, errp); + ret = bdrv_co_create_file(filename, opts, errp); if (ret < 0) { goto fail; } diff --git a/block/raw-format.c b/block/raw-format.c index XXXXXXX..XXXXXXX 100644 --- a/block/raw-format.c +++ b/block/raw-format.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn raw_co_create_opts(BlockDriver *drv, QemuOpts *opts, Error **errp) { - return bdrv_create_file(filename, opts, errp); + return bdrv_co_create_file(filename, opts, errp); } static int raw_open(BlockDriverState *bs, QDict *options, int flags, diff --git a/block/vdi.c b/block/vdi.c index XXXXXXX..XXXXXXX 100644 --- a/block/vdi.c +++ b/block/vdi.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn vdi_co_create_opts(BlockDriver *drv, qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vdi_create_opts, true); /* Create and open the file (protocol layer) */ - ret = bdrv_create_file(filename, opts, errp); + ret = bdrv_co_create_file(filename, opts, errp); if (ret < 0) { goto done; } diff --git a/block/vhdx.c b/block/vhdx.c index XXXXXXX..XXXXXXX 100644 --- a/block/vhdx.c +++ b/block/vhdx.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn vhdx_co_create_opts(BlockDriver *drv, } /* Create and open the file (protocol layer) */ - ret = bdrv_create_file(filename, opts, errp); + ret = bdrv_co_create_file(filename, opts, errp); if (ret < 0) { goto fail; } diff --git a/block/vmdk.c b/block/vmdk.c index XXXXXXX..XXXXXXX 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn vmdk_create_extent(const char *filename, int ret; BlockBackend *blk = NULL; - ret = bdrv_create_file(filename, opts, errp); + ret = bdrv_co_create_file(filename, opts, errp); if (ret < 0) { goto exit; } diff --git a/block/vpc.c b/block/vpc.c index XXXXXXX..XXXXXXX 100644 --- a/block/vpc.c +++ b/block/vpc.c @@ -XXX,XX +XXX,XX @@ static int coroutine_fn vpc_co_create_opts(BlockDriver *drv, } /* Create and open the file (protocol layer) */ - ret = bdrv_create_file(filename, opts, errp); + ret = bdrv_co_create_file(filename, opts, errp); if (ret < 0) { goto fail; } -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> In preparation to the incoming new function specifiers, rename g_c_w with a more meaningful name and document it. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-10-eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- docs/devel/block-coroutine-wrapper.rst | 6 +-- block/coroutines.h | 4 +- include/block/block-common.h | 11 +++-- include/block/block-io.h | 44 ++++++++--------- include/sysemu/block-backend-io.h | 68 +++++++++++++------------- scripts/block-coroutine-wrapper.py | 6 +-- 6 files changed, 71 insertions(+), 68 deletions(-) diff --git a/docs/devel/block-coroutine-wrapper.rst b/docs/devel/block-coroutine-wrapper.rst index XXXXXXX..XXXXXXX 100644 --- a/docs/devel/block-coroutine-wrapper.rst +++ b/docs/devel/block-coroutine-wrapper.rst @@ -XXX,XX +XXX,XX @@ called ``bdrv_foo(<same args>)``. In this case the script can help. To trigger the generation: 1. You need ``bdrv_foo`` declaration somewhere (for example, in - ``block/coroutines.h``) with the ``generated_co_wrapper`` mark, + ``block/coroutines.h``) with the ``co_wrapper_mixed`` mark, like this: .. code-block:: c - int generated_co_wrapper bdrv_foo(<some args>); + int co_wrapper_mixed bdrv_foo(<some args>); 2. You need to feed this declaration to block-coroutine-wrapper script. For this, add the .h (or .c) file with the declaration to the @@ -XXX,XX +XXX,XX @@ Links 1. The script location is ``scripts/block-coroutine-wrapper.py``. -2. Generic place for private ``generated_co_wrapper`` declarations is +2. Generic place for private ``co_wrapper_mixed`` declarations is ``block/coroutines.h``, for public declarations: ``include/block/block.h`` diff --git a/block/coroutines.h b/block/coroutines.h index XXXXXXX..XXXXXXX 100644 --- a/block/coroutines.h +++ b/block/coroutines.h @@ -XXX,XX +XXX,XX @@ nbd_co_do_establish_connection(BlockDriverState *bs, bool blocking, * the "I/O or GS" API. */ -int generated_co_wrapper +int co_wrapper_mixed bdrv_common_block_status_above(BlockDriverState *bs, BlockDriverState *base, bool include_base, @@ -XXX,XX +XXX,XX @@ bdrv_common_block_status_above(BlockDriverState *bs, int64_t *map, BlockDriverState **file, int *depth); -int generated_co_wrapper +int co_wrapper_mixed nbd_do_establish_connection(BlockDriverState *bs, bool blocking, Error **errp); #endif /* BLOCK_COROUTINES_H */ diff --git a/include/block/block-common.h b/include/block/block-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-common.h +++ b/include/block/block-common.h @@ -XXX,XX +XXX,XX @@ #include "qemu/transactions.h" /* - * generated_co_wrapper + * co_wrapper{*}: Function specifiers used by block-coroutine-wrapper.py * - * Function specifier, which does nothing but mark functions to be + * Function specifiers, which do nothing but mark functions to be * generated by scripts/block-coroutine-wrapper.py * - * Read more in docs/devel/block-coroutine-wrapper.rst + * Usage: read docs/devel/block-coroutine-wrapper.rst + * + * co_wrapper_mixed functions can be called by both coroutine and + * non-coroutine context. */ -#define generated_co_wrapper +#define co_wrapper_mixed /* block.c */ typedef struct BlockDriver BlockDriver; diff --git a/include/block/block-io.h b/include/block/block-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -XXX,XX +XXX,XX @@ * to catch when they are accidentally called by the wrong API. */ -int generated_co_wrapper bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset, - int64_t bytes, - BdrvRequestFlags flags); +int co_wrapper_mixed bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset, + int64_t bytes, + BdrvRequestFlags flags); int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags); -int generated_co_wrapper bdrv_pread(BdrvChild *child, int64_t offset, - int64_t bytes, void *buf, - BdrvRequestFlags flags); -int generated_co_wrapper bdrv_pwrite(BdrvChild *child, int64_t offset, - int64_t bytes, const void *buf, - BdrvRequestFlags flags); -int generated_co_wrapper bdrv_pwrite_sync(BdrvChild *child, int64_t offset, - int64_t bytes, const void *buf, - BdrvRequestFlags flags); +int co_wrapper_mixed bdrv_pread(BdrvChild *child, int64_t offset, + int64_t bytes, void *buf, + BdrvRequestFlags flags); +int co_wrapper_mixed bdrv_pwrite(BdrvChild *child, int64_t offset, + int64_t bytes, const void *buf, + BdrvRequestFlags flags); +int co_wrapper_mixed bdrv_pwrite_sync(BdrvChild *child, int64_t offset, + int64_t bytes, const void *buf, + BdrvRequestFlags flags); int coroutine_fn bdrv_co_pwrite_sync(BdrvChild *child, int64_t offset, int64_t bytes, const void *buf, BdrvRequestFlags flags); @@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset, void bdrv_drain(BlockDriverState *bs); -int generated_co_wrapper +int co_wrapper_mixed bdrv_truncate(BdrvChild *child, int64_t offset, bool exact, PreallocMode prealloc, BdrvRequestFlags flags, Error **errp); -int generated_co_wrapper bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, - BdrvCheckMode fix); +int co_wrapper_mixed bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, + BdrvCheckMode fix); /* Invalidate any cached metadata used by image formats */ -int generated_co_wrapper bdrv_invalidate_cache(BlockDriverState *bs, - Error **errp); -int generated_co_wrapper bdrv_flush(BlockDriverState *bs); -int generated_co_wrapper bdrv_pdiscard(BdrvChild *child, int64_t offset, - int64_t bytes); -int generated_co_wrapper +int co_wrapper_mixed bdrv_invalidate_cache(BlockDriverState *bs, + Error **errp); +int co_wrapper_mixed bdrv_flush(BlockDriverState *bs); +int co_wrapper_mixed bdrv_pdiscard(BdrvChild *child, int64_t offset, + int64_t bytes); +int co_wrapper_mixed bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); -int generated_co_wrapper +int co_wrapper_mixed bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); /** diff --git a/include/sysemu/block-backend-io.h b/include/sysemu/block-backend-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/sysemu/block-backend-io.h +++ b/include/sysemu/block-backend-io.h @@ -XXX,XX +XXX,XX @@ int coroutine_fn blk_co_is_allocated_above(BlockBackend *blk, * the "I/O or GS" API. */ -int generated_co_wrapper blk_pread(BlockBackend *blk, int64_t offset, - int64_t bytes, void *buf, - BdrvRequestFlags flags); +int co_wrapper_mixed blk_pread(BlockBackend *blk, int64_t offset, + int64_t bytes, void *buf, + BdrvRequestFlags flags); int coroutine_fn blk_co_pread(BlockBackend *blk, int64_t offset, int64_t bytes, void *buf, BdrvRequestFlags flags); -int generated_co_wrapper blk_preadv(BlockBackend *blk, int64_t offset, - int64_t bytes, QEMUIOVector *qiov, - BdrvRequestFlags flags); +int co_wrapper_mixed blk_preadv(BlockBackend *blk, int64_t offset, + int64_t bytes, QEMUIOVector *qiov, + BdrvRequestFlags flags); int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags); -int generated_co_wrapper blk_preadv_part(BlockBackend *blk, int64_t offset, - int64_t bytes, QEMUIOVector *qiov, - size_t qiov_offset, - BdrvRequestFlags flags); +int co_wrapper_mixed blk_preadv_part(BlockBackend *blk, int64_t offset, + int64_t bytes, QEMUIOVector *qiov, + size_t qiov_offset, + BdrvRequestFlags flags); int coroutine_fn blk_co_preadv_part(BlockBackend *blk, int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); -int generated_co_wrapper blk_pwrite(BlockBackend *blk, int64_t offset, - int64_t bytes, const void *buf, - BdrvRequestFlags flags); +int co_wrapper_mixed blk_pwrite(BlockBackend *blk, int64_t offset, + int64_t bytes, const void *buf, + BdrvRequestFlags flags); int coroutine_fn blk_co_pwrite(BlockBackend *blk, int64_t offset, int64_t bytes, const void *buf, BdrvRequestFlags flags); -int generated_co_wrapper blk_pwritev(BlockBackend *blk, int64_t offset, - int64_t bytes, QEMUIOVector *qiov, - BdrvRequestFlags flags); +int co_wrapper_mixed blk_pwritev(BlockBackend *blk, int64_t offset, + int64_t bytes, QEMUIOVector *qiov, + BdrvRequestFlags flags); int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags); -int generated_co_wrapper blk_pwritev_part(BlockBackend *blk, int64_t offset, - int64_t bytes, QEMUIOVector *qiov, - size_t qiov_offset, - BdrvRequestFlags flags); +int co_wrapper_mixed blk_pwritev_part(BlockBackend *blk, int64_t offset, + int64_t bytes, QEMUIOVector *qiov, + size_t qiov_offset, + BdrvRequestFlags flags); int coroutine_fn blk_co_pwritev_part(BlockBackend *blk, int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); -int generated_co_wrapper blk_pwrite_compressed(BlockBackend *blk, - int64_t offset, int64_t bytes, - const void *buf); +int co_wrapper_mixed blk_pwrite_compressed(BlockBackend *blk, + int64_t offset, int64_t bytes, + const void *buf); int coroutine_fn blk_co_pwrite_compressed(BlockBackend *blk, int64_t offset, int64_t bytes, const void *buf); -int generated_co_wrapper blk_pwrite_zeroes(BlockBackend *blk, int64_t offset, - int64_t bytes, - BdrvRequestFlags flags); +int co_wrapper_mixed blk_pwrite_zeroes(BlockBackend *blk, int64_t offset, + int64_t bytes, + BdrvRequestFlags flags); int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset, int64_t bytes, BdrvRequestFlags flags); -int generated_co_wrapper blk_pdiscard(BlockBackend *blk, int64_t offset, - int64_t bytes); +int co_wrapper_mixed blk_pdiscard(BlockBackend *blk, int64_t offset, + int64_t bytes); int coroutine_fn blk_co_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes); -int generated_co_wrapper blk_flush(BlockBackend *blk); +int co_wrapper_mixed blk_flush(BlockBackend *blk); int coroutine_fn blk_co_flush(BlockBackend *blk); -int generated_co_wrapper blk_ioctl(BlockBackend *blk, unsigned long int req, - void *buf); +int co_wrapper_mixed blk_ioctl(BlockBackend *blk, unsigned long int req, + void *buf); int coroutine_fn blk_co_ioctl(BlockBackend *blk, unsigned long int req, void *buf); -int generated_co_wrapper blk_truncate(BlockBackend *blk, int64_t offset, - bool exact, PreallocMode prealloc, - BdrvRequestFlags flags, Error **errp); +int co_wrapper_mixed blk_truncate(BlockBackend *blk, int64_t offset, + bool exact, PreallocMode prealloc, + BdrvRequestFlags flags, Error **errp); int coroutine_fn blk_co_truncate(BlockBackend *blk, int64_t offset, bool exact, PreallocMode prealloc, BdrvRequestFlags flags, Error **errp); diff --git a/scripts/block-coroutine-wrapper.py b/scripts/block-coroutine-wrapper.py index XXXXXXX..XXXXXXX 100644 --- a/scripts/block-coroutine-wrapper.py +++ b/scripts/block-coroutine-wrapper.py @@ -XXX,XX +XXX,XX @@ """Generate coroutine wrappers for block subsystem. The program parses one or several concatenated c files from stdin, -searches for functions with the 'generated_co_wrapper' specifier +searches for functions with the 'co_wrapper_mixed' specifier and generates corresponding wrappers on stdout. Usage: block-coroutine-wrapper.py generated-file.c FILE.[ch]... @@ -XXX,XX +XXX,XX @@ def gen_block(self, format: str) -> str: return '\n'.join(format.format_map(arg.__dict__) for arg in self.args) -# Match wrappers declared with a generated_co_wrapper mark -func_decl_re = re.compile(r'^int\s*generated_co_wrapper\s*' +# Match wrappers declared with a co_wrapper_mixed mark +func_decl_re = re.compile(r'^int\s*co_wrapper_mixed\s*' r'(?P<wrapper_name>[a-z][a-z0-9_]*)' r'\((?P<args>[^)]*)\);$', re.MULTILINE) -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> This new annotation starts just a function wrapper that creates a new coroutine. It assumes the caller is not a coroutine. It will be the default annotation to be used in the future. This is much better as c_w_mixed, because it is clear if the caller is a coroutine or not, and provides the advantage of automating the code creation. In the future all c_w_mixed functions will be substituted by co_wrapper. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-11-eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- docs/devel/block-coroutine-wrapper.rst | 6 +- include/block/block-common.h | 8 +- scripts/block-coroutine-wrapper.py | 110 +++++++++++++++++-------- 3 files changed, 86 insertions(+), 38 deletions(-) diff --git a/docs/devel/block-coroutine-wrapper.rst b/docs/devel/block-coroutine-wrapper.rst index XXXXXXX..XXXXXXX 100644 --- a/docs/devel/block-coroutine-wrapper.rst +++ b/docs/devel/block-coroutine-wrapper.rst @@ -XXX,XX +XXX,XX @@ called ``bdrv_foo(<same args>)``. In this case the script can help. To trigger the generation: 1. You need ``bdrv_foo`` declaration somewhere (for example, in - ``block/coroutines.h``) with the ``co_wrapper_mixed`` mark, + ``block/coroutines.h``) with the ``co_wrapper`` mark, like this: .. code-block:: c - int co_wrapper_mixed bdrv_foo(<some args>); + int co_wrapper bdrv_foo(<some args>); 2. You need to feed this declaration to block-coroutine-wrapper script. For this, add the .h (or .c) file with the declaration to the @@ -XXX,XX +XXX,XX @@ Links 1. The script location is ``scripts/block-coroutine-wrapper.py``. -2. Generic place for private ``co_wrapper_mixed`` declarations is +2. Generic place for private ``co_wrapper`` declarations is ``block/coroutines.h``, for public declarations: ``include/block/block.h`` diff --git a/include/block/block-common.h b/include/block/block-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-common.h +++ b/include/block/block-common.h @@ -XXX,XX +XXX,XX @@ * * Usage: read docs/devel/block-coroutine-wrapper.rst * - * co_wrapper_mixed functions can be called by both coroutine and - * non-coroutine context. + * There are 2 kind of specifiers: + * - co_wrapper functions can be called by only non-coroutine context, because + * they always generate a new coroutine. + * - co_wrapper_mixed functions can be called by both coroutine and + * non-coroutine context. */ +#define co_wrapper #define co_wrapper_mixed /* block.c */ diff --git a/scripts/block-coroutine-wrapper.py b/scripts/block-coroutine-wrapper.py index XXXXXXX..XXXXXXX 100644 --- a/scripts/block-coroutine-wrapper.py +++ b/scripts/block-coroutine-wrapper.py @@ -XXX,XX +XXX,XX @@ """Generate coroutine wrappers for block subsystem. The program parses one or several concatenated c files from stdin, -searches for functions with the 'co_wrapper_mixed' specifier +searches for functions with the 'co_wrapper' specifier and generates corresponding wrappers on stdout. Usage: block-coroutine-wrapper.py generated-file.c FILE.[ch]... @@ -XXX,XX +XXX,XX @@ def __init__(self, param_decl: str) -> None: class FuncDecl: - def __init__(self, return_type: str, name: str, args: str) -> None: + def __init__(self, return_type: str, name: str, args: str, + variant: str) -> None: self.return_type = return_type.strip() self.name = name.strip() + self.struct_name = snake_to_camel(self.name) self.args = [ParamDecl(arg.strip()) for arg in args.split(',')] + self.create_only_co = 'mixed' not in variant + + subsystem, subname = self.name.split('_', 1) + self.co_name = f'{subsystem}_co_{subname}' + + t = self.args[0].type + if t == 'BlockDriverState *': + bs = 'bs' + elif t == 'BdrvChild *': + bs = 'child->bs' + else: + bs = 'blk_bs(blk)' + self.bs = bs def gen_list(self, format: str) -> str: return ', '.join(format.format_map(arg.__dict__) for arg in self.args) @@ -XXX,XX +XXX,XX @@ def gen_block(self, format: str) -> str: return '\n'.join(format.format_map(arg.__dict__) for arg in self.args) -# Match wrappers declared with a co_wrapper_mixed mark -func_decl_re = re.compile(r'^int\s*co_wrapper_mixed\s*' +# Match wrappers declared with a co_wrapper mark +func_decl_re = re.compile(r'^int\s*co_wrapper' + r'(?P<variant>(_[a-z][a-z0-9_]*)?)\s*' r'(?P<wrapper_name>[a-z][a-z0-9_]*)' r'\((?P<args>[^)]*)\);$', re.MULTILINE) @@ -XXX,XX +XXX,XX @@ def func_decl_iter(text: str) -> Iterator: for m in func_decl_re.finditer(text): yield FuncDecl(return_type='int', name=m.group('wrapper_name'), - args=m.group('args')) + args=m.group('args'), + variant=m.group('variant')) def snake_to_camel(func_name: str) -> str: @@ -XXX,XX +XXX,XX @@ def snake_to_camel(func_name: str) -> str: return ''.join(words) +def create_mixed_wrapper(func: FuncDecl) -> str: + """ + Checks if we are already in coroutine + """ + name = func.co_name + struct_name = func.struct_name + return f"""\ +int {func.name}({ func.gen_list('{decl}') }) +{{ + if (qemu_in_coroutine()) {{ + return {name}({ func.gen_list('{name}') }); + }} else {{ + {struct_name} s = {{ + .poll_state.bs = {func.bs}, + .poll_state.in_progress = true, + +{ func.gen_block(' .{name} = {name},') } + }}; + + s.poll_state.co = qemu_coroutine_create({name}_entry, &s); + + return bdrv_poll_co(&s.poll_state); + }} +}}""" + + +def create_co_wrapper(func: FuncDecl) -> str: + """ + Assumes we are not in coroutine, and creates one + """ + name = func.co_name + struct_name = func.struct_name + return f"""\ +int {func.name}({ func.gen_list('{decl}') }) +{{ + {struct_name} s = {{ + .poll_state.bs = {func.bs}, + .poll_state.in_progress = true, + +{ func.gen_block(' .{name} = {name},') } + }}; + assert(!qemu_in_coroutine()); + + s.poll_state.co = qemu_coroutine_create({name}_entry, &s); + + return bdrv_poll_co(&s.poll_state); +}}""" + + def gen_wrapper(func: FuncDecl) -> str: assert not '_co_' in func.name assert func.return_type == 'int' assert func.args[0].type in ['BlockDriverState *', 'BdrvChild *', 'BlockBackend *'] - subsystem, subname = func.name.split('_', 1) - - name = f'{subsystem}_co_{subname}' + name = func.co_name + struct_name = func.struct_name - t = func.args[0].type - if t == 'BlockDriverState *': - bs = 'bs' - elif t == 'BdrvChild *': - bs = 'child->bs' - else: - bs = 'blk_bs(blk)' - struct_name = snake_to_camel(name) + creation_function = create_mixed_wrapper + if func.create_only_co: + creation_function = create_co_wrapper return f"""\ /* @@ -XXX,XX +XXX,XX @@ def gen_wrapper(func: FuncDecl) -> str: aio_wait_kick(); }} -int {func.name}({ func.gen_list('{decl}') }) -{{ - if (qemu_in_coroutine()) {{ - return {name}({ func.gen_list('{name}') }); - }} else {{ - {struct_name} s = {{ - .poll_state.bs = {bs}, - .poll_state.in_progress = true, - -{ func.gen_block(' .{name} = {name},') } - }}; - - s.poll_state.co = qemu_coroutine_create({name}_entry, &s); - - return bdrv_poll_co(&s.poll_state); - }} -}}""" +{creation_function(func)}""" def gen_wrappers(input_code: str) -> str: -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> Right now, we take the first parameter of the function to get the BlockDriverState to pass to bdrv_poll_co(), that internally calls functions that figure in which aiocontext the coroutine should run. However, it is useless to pass a bs just to get its own AioContext, so instead pass it directly, and default to the main loop if no BlockDriverState is passed as parameter. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-12-eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/block-gen.h | 6 +++--- scripts/block-coroutine-wrapper.py | 16 ++++++++-------- 2 files changed, 11 insertions(+), 11 deletions(-) diff --git a/block/block-gen.h b/block/block-gen.h index XXXXXXX..XXXXXXX 100644 --- a/block/block-gen.h +++ b/block/block-gen.h @@ -XXX,XX +XXX,XX @@ /* Base structure for argument packing structures */ typedef struct BdrvPollCo { - BlockDriverState *bs; + AioContext *ctx; bool in_progress; int ret; Coroutine *co; /* Keep pointer here for debugging */ @@ -XXX,XX +XXX,XX @@ static inline int bdrv_poll_co(BdrvPollCo *s) { assert(!qemu_in_coroutine()); - bdrv_coroutine_enter(s->bs, s->co); - BDRV_POLL_WHILE(s->bs, s->in_progress); + aio_co_enter(s->ctx, s->co); + AIO_WAIT_WHILE(s->ctx, s->in_progress); return s->ret; } diff --git a/scripts/block-coroutine-wrapper.py b/scripts/block-coroutine-wrapper.py index XXXXXXX..XXXXXXX 100644 --- a/scripts/block-coroutine-wrapper.py +++ b/scripts/block-coroutine-wrapper.py @@ -XXX,XX +XXX,XX @@ def __init__(self, return_type: str, name: str, args: str, t = self.args[0].type if t == 'BlockDriverState *': - bs = 'bs' + ctx = 'bdrv_get_aio_context(bs)' elif t == 'BdrvChild *': - bs = 'child->bs' + ctx = 'bdrv_get_aio_context(child->bs)' + elif t == 'BlockBackend *': + ctx = 'blk_get_aio_context(blk)' else: - bs = 'blk_bs(blk)' - self.bs = bs + ctx = 'qemu_get_aio_context()' + self.ctx = ctx def gen_list(self, format: str) -> str: return ', '.join(format.format_map(arg.__dict__) for arg in self.args) @@ -XXX,XX +XXX,XX @@ def create_mixed_wrapper(func: FuncDecl) -> str: return {name}({ func.gen_list('{name}') }); }} else {{ {struct_name} s = {{ - .poll_state.bs = {func.bs}, + .poll_state.ctx = {func.ctx}, .poll_state.in_progress = true, { func.gen_block(' .{name} = {name},') } @@ -XXX,XX +XXX,XX @@ def create_co_wrapper(func: FuncDecl) -> str: int {func.name}({ func.gen_list('{decl}') }) {{ {struct_name} s = {{ - .poll_state.bs = {func.bs}, + .poll_state.ctx = {func.ctx}, .poll_state.in_progress = true, { func.gen_block(' .{name} = {name},') } @@ -XXX,XX +XXX,XX @@ def create_co_wrapper(func: FuncDecl) -> str: def gen_wrapper(func: FuncDecl) -> str: assert not '_co_' in func.name assert func.return_type == 'int' - assert func.args[0].type in ['BlockDriverState *', 'BdrvChild *', - 'BlockBackend *'] name = func.co_name struct_name = func.struct_name -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> Extend the regex to cover also return type, pointers included. This implies that the value returned by the function cannot be a simple "int" anymore, but the custom return type. Therefore remove poll_state->ret and instead use a per-function custom "ret" field. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-13-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/block-gen.h | 5 +---- scripts/block-coroutine-wrapper.py | 19 +++++++++++-------- 2 files changed, 12 insertions(+), 12 deletions(-) diff --git a/block/block-gen.h b/block/block-gen.h index XXXXXXX..XXXXXXX 100644 --- a/block/block-gen.h +++ b/block/block-gen.h @@ -XXX,XX +XXX,XX @@ typedef struct BdrvPollCo { AioContext *ctx; bool in_progress; - int ret; Coroutine *co; /* Keep pointer here for debugging */ } BdrvPollCo; -static inline int bdrv_poll_co(BdrvPollCo *s) +static inline void bdrv_poll_co(BdrvPollCo *s) { assert(!qemu_in_coroutine()); aio_co_enter(s->ctx, s->co); AIO_WAIT_WHILE(s->ctx, s->in_progress); - - return s->ret; } #endif /* BLOCK_BLOCK_GEN_H */ diff --git a/scripts/block-coroutine-wrapper.py b/scripts/block-coroutine-wrapper.py index XXXXXXX..XXXXXXX 100644 --- a/scripts/block-coroutine-wrapper.py +++ b/scripts/block-coroutine-wrapper.py @@ -XXX,XX +XXX,XX @@ def gen_block(self, format: str) -> str: # Match wrappers declared with a co_wrapper mark -func_decl_re = re.compile(r'^int\s*co_wrapper' +func_decl_re = re.compile(r'^(?P<return_type>[a-zA-Z][a-zA-Z0-9_]* [\*]?)' + r'\s*co_wrapper' r'(?P<variant>(_[a-z][a-z0-9_]*)?)\s*' r'(?P<wrapper_name>[a-z][a-z0-9_]*)' r'\((?P<args>[^)]*)\);$', re.MULTILINE) @@ -XXX,XX +XXX,XX @@ def gen_block(self, format: str) -> str: def func_decl_iter(text: str) -> Iterator: for m in func_decl_re.finditer(text): - yield FuncDecl(return_type='int', + yield FuncDecl(return_type=m.group('return_type'), name=m.group('wrapper_name'), args=m.group('args'), variant=m.group('variant')) @@ -XXX,XX +XXX,XX @@ def create_mixed_wrapper(func: FuncDecl) -> str: name = func.co_name struct_name = func.struct_name return f"""\ -int {func.name}({ func.gen_list('{decl}') }) +{func.return_type} {func.name}({ func.gen_list('{decl}') }) {{ if (qemu_in_coroutine()) {{ return {name}({ func.gen_list('{name}') }); @@ -XXX,XX +XXX,XX @@ def create_mixed_wrapper(func: FuncDecl) -> str: s.poll_state.co = qemu_coroutine_create({name}_entry, &s); - return bdrv_poll_co(&s.poll_state); + bdrv_poll_co(&s.poll_state); + return s.ret; }} }}""" @@ -XXX,XX +XXX,XX @@ def create_co_wrapper(func: FuncDecl) -> str: name = func.co_name struct_name = func.struct_name return f"""\ -int {func.name}({ func.gen_list('{decl}') }) +{func.return_type} {func.name}({ func.gen_list('{decl}') }) {{ {struct_name} s = {{ .poll_state.ctx = {func.ctx}, @@ -XXX,XX +XXX,XX @@ def create_co_wrapper(func: FuncDecl) -> str: s.poll_state.co = qemu_coroutine_create({name}_entry, &s); - return bdrv_poll_co(&s.poll_state); + bdrv_poll_co(&s.poll_state); + return s.ret; }}""" def gen_wrapper(func: FuncDecl) -> str: assert not '_co_' in func.name - assert func.return_type == 'int' name = func.co_name struct_name = func.struct_name @@ -XXX,XX +XXX,XX @@ def gen_wrapper(func: FuncDecl) -> str: typedef struct {struct_name} {{ BdrvPollCo poll_state; + {func.return_type} ret; { func.gen_block(' {decl};') } }} {struct_name}; @@ -XXX,XX +XXX,XX @@ def gen_wrapper(func: FuncDecl) -> str: {{ {struct_name} *s = opaque; - s->poll_state.ret = {name}({ func.gen_list('s->{name}') }); + s->ret = {name}({ func.gen_list('s->{name}') }); s->poll_state.in_progress = false; aio_wait_kick(); -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> This function is never called in coroutine context, therefore instead of manually creating a new coroutine, delegate it to the block-coroutine-wrapper script, defining it as co_wrapper. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-14-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-global-state.h | 8 ++++-- block.c | 41 ++---------------------------- 2 files changed, 8 insertions(+), 41 deletions(-) diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -XXX,XX +XXX,XX @@ BlockDriver *bdrv_find_protocol(const char *filename, bool allow_protocol_prefix, Error **errp); BlockDriver *bdrv_find_format(const char *format_name); -int bdrv_create(BlockDriver *drv, const char* filename, - QemuOpts *opts, Error **errp); + +int coroutine_fn bdrv_co_create(BlockDriver *drv, const char *filename, + QemuOpts *opts, Error **errp); +int co_wrapper bdrv_create(BlockDriver *drv, const char *filename, + QemuOpts *opts, Error **errp); + int coroutine_fn bdrv_co_create_file(const char *filename, QemuOpts *opts, Error **errp); diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ typedef struct CreateCo { Error *err; } CreateCo; -static int coroutine_fn bdrv_co_create(BlockDriver *drv, const char *filename, - QemuOpts *opts, Error **errp) +int coroutine_fn bdrv_co_create(BlockDriver *drv, const char *filename, + QemuOpts *opts, Error **errp) { int ret; GLOBAL_STATE_CODE(); @@ -XXX,XX +XXX,XX @@ static int coroutine_fn bdrv_co_create(BlockDriver *drv, const char *filename, return ret; } -static void coroutine_fn bdrv_create_co_entry(void *opaque) -{ - CreateCo *cco = opaque; - GLOBAL_STATE_CODE(); - - cco->ret = bdrv_co_create(cco->drv, cco->filename, cco->opts, &cco->err); - aio_wait_kick(); -} - -int bdrv_create(BlockDriver *drv, const char* filename, - QemuOpts *opts, Error **errp) -{ - GLOBAL_STATE_CODE(); - - if (qemu_in_coroutine()) { - /* Fast-path if already in coroutine context */ - return bdrv_co_create(drv, filename, opts, errp); - } else { - Coroutine *co; - CreateCo cco = { - .drv = drv, - .filename = filename, - .opts = opts, - .ret = NOT_DONE, - .err = NULL, - }; - - co = qemu_coroutine_create(bdrv_create_co_entry, &cco); - qemu_coroutine_enter(co); - while (cco.ret == NOT_DONE) { - aio_poll(qemu_get_aio_context(), true); - } - error_propagate(errp, cco.err); - return cco.ret; - } -} - /** * Helper function for bdrv_create_file_fallback(): Resize @blk to at * least the given @minimum_size. -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> bdrv_can_store_new_dirty_bitmap and bdrv_remove_persistent_dirty_bitmap check if they are running in a coroutine, directly calling the coroutine callback if it's the case. Except that no coroutine calls such functions, therefore that check can be removed, and function creation can be offloaded to c_w. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-15-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-common.h | 5 +- include/block/block-io.h | 10 +++- include/block/dirty-bitmap.h | 10 +++- block/dirty-bitmap.c | 88 +----------------------------------- block/meson.build | 1 + 5 files changed, 22 insertions(+), 92 deletions(-) diff --git a/include/block/block-common.h b/include/block/block-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-common.h +++ b/include/block/block-common.h @@ -XXX,XX +XXX,XX @@ #include "qemu/iov.h" #include "qemu/coroutine.h" #include "block/accounting.h" -#include "block/dirty-bitmap.h" -#include "block/blockjob.h" #include "qemu/hbitmap.h" #include "qemu/transactions.h" @@ -XXX,XX +XXX,XX @@ #define co_wrapper #define co_wrapper_mixed +#include "block/dirty-bitmap.h" +#include "block/blockjob.h" + /* block.c */ typedef struct BlockDriver BlockDriver; typedef struct BdrvChild BdrvChild; diff --git a/include/block/block-io.h b/include/block/block-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -XXX,XX +XXX,XX @@ AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c); void bdrv_io_plug(BlockDriverState *bs); void bdrv_io_unplug(BlockDriverState *bs); -bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, - uint32_t granularity, Error **errp); +bool coroutine_fn bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, + const char *name, + uint32_t granularity, + Error **errp); +bool co_wrapper bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, + const char *name, + uint32_t granularity, + Error **errp); /** * diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/dirty-bitmap.h +++ b/include/block/dirty-bitmap.h @@ -XXX,XX +XXX,XX @@ int bdrv_dirty_bitmap_check(const BdrvDirtyBitmap *bitmap, uint32_t flags, Error **errp); void bdrv_release_dirty_bitmap(BdrvDirtyBitmap *bitmap); void bdrv_release_named_dirty_bitmaps(BlockDriverState *bs); -int bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name, - Error **errp); + +int coroutine_fn bdrv_co_remove_persistent_dirty_bitmap(BlockDriverState *bs, + const char *name, + Error **errp); +int co_wrapper bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs, + const char *name, + Error **errp); + void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap); void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap); void bdrv_enable_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap); diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c index XXXXXXX..XXXXXXX 100644 --- a/block/dirty-bitmap.c +++ b/block/dirty-bitmap.c @@ -XXX,XX +XXX,XX @@ void bdrv_release_named_dirty_bitmaps(BlockDriverState *bs) * not fail. * This function doesn't release corresponding BdrvDirtyBitmap. */ -static int coroutine_fn +int coroutine_fn bdrv_co_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name, Error **errp) { @@ -XXX,XX +XXX,XX @@ bdrv_co_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name, return 0; } -typedef struct BdrvRemovePersistentDirtyBitmapCo { - BlockDriverState *bs; - const char *name; - Error **errp; - int ret; -} BdrvRemovePersistentDirtyBitmapCo; - -static void coroutine_fn -bdrv_co_remove_persistent_dirty_bitmap_entry(void *opaque) -{ - BdrvRemovePersistentDirtyBitmapCo *s = opaque; - - s->ret = bdrv_co_remove_persistent_dirty_bitmap(s->bs, s->name, s->errp); - aio_wait_kick(); -} - -int bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name, - Error **errp) -{ - if (qemu_in_coroutine()) { - return bdrv_co_remove_persistent_dirty_bitmap(bs, name, errp); - } else { - Coroutine *co; - BdrvRemovePersistentDirtyBitmapCo s = { - .bs = bs, - .name = name, - .errp = errp, - .ret = -EINPROGRESS, - }; - - co = qemu_coroutine_create(bdrv_co_remove_persistent_dirty_bitmap_entry, - &s); - bdrv_coroutine_enter(bs, co); - BDRV_POLL_WHILE(bs, s.ret == -EINPROGRESS); - - return s.ret; - } -} - bool bdrv_supports_persistent_dirty_bitmap(BlockDriverState *bs) { @@ -XXX,XX +XXX,XX @@ bdrv_supports_persistent_dirty_bitmap(BlockDriverState *bs) return false; } -static bool coroutine_fn +bool coroutine_fn bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, uint32_t granularity, Error **errp) { @@ -XXX,XX +XXX,XX @@ bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, return drv->bdrv_co_can_store_new_dirty_bitmap(bs, name, granularity, errp); } -typedef struct BdrvCanStoreNewDirtyBitmapCo { - BlockDriverState *bs; - const char *name; - uint32_t granularity; - Error **errp; - bool ret; - - bool in_progress; -} BdrvCanStoreNewDirtyBitmapCo; - -static void coroutine_fn bdrv_co_can_store_new_dirty_bitmap_entry(void *opaque) -{ - BdrvCanStoreNewDirtyBitmapCo *s = opaque; - - s->ret = bdrv_co_can_store_new_dirty_bitmap(s->bs, s->name, s->granularity, - s->errp); - s->in_progress = false; - aio_wait_kick(); -} - -bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, - uint32_t granularity, Error **errp) -{ - IO_CODE(); - if (qemu_in_coroutine()) { - return bdrv_co_can_store_new_dirty_bitmap(bs, name, granularity, errp); - } else { - Coroutine *co; - BdrvCanStoreNewDirtyBitmapCo s = { - .bs = bs, - .name = name, - .granularity = granularity, - .errp = errp, - .in_progress = true, - }; - - co = qemu_coroutine_create(bdrv_co_can_store_new_dirty_bitmap_entry, - &s); - bdrv_coroutine_enter(bs, co); - BDRV_POLL_WHILE(bs, s.in_progress); - - return s.ret; - } -} - void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap) { bdrv_dirty_bitmaps_lock(bitmap->bs); diff --git a/block/meson.build b/block/meson.build index XXXXXXX..XXXXXXX 100644 --- a/block/meson.build +++ b/block/meson.build @@ -XXX,XX +XXX,XX @@ block_gen_c = custom_target('block-gen.c', output: 'block-gen.c', input: files( '../include/block/block-io.h', + '../include/block/dirty-bitmap.h', '../include/block/block-global-state.h', '../include/sysemu/block-backend-io.h', 'coroutines.h' -- 2.38.1 Provide a separate function that just quiesces the users of a node to prevent new requests from coming in, but without waiting for the already in-flight I/O to complete. This function can be used in contexts where polling is not allowed. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-2-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-global-state.h | 1 + block/io.c | 19 +++++++++++++------ 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -XXX,XX +XXX,XX @@ int bdrv_inactivate_all(void); int bdrv_flush_all(void); void bdrv_close_all(void); void bdrv_drain_all_begin(void); +void bdrv_drain_all_begin_nopoll(void); void bdrv_drain_all_end(void); void bdrv_drain_all(void); diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ static bool bdrv_drain_all_poll(void) * NOTE: no new block jobs or BlockDriverStates can be created between * the bdrv_drain_all_begin() and bdrv_drain_all_end() calls. */ -void bdrv_drain_all_begin(void) +void bdrv_drain_all_begin_nopoll(void) { BlockDriverState *bs = NULL; GLOBAL_STATE_CODE(); - if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(NULL, true, NULL, true); - return; - } - /* * bdrv queue is managed by record/replay, * waiting for finishing the I/O requests may @@ -XXX,XX +XXX,XX @@ void bdrv_drain_all_begin(void) bdrv_do_drained_begin(bs, NULL, false); aio_context_release(aio_context); } +} + +void bdrv_drain_all_begin(void) +{ + BlockDriverState *bs = NULL; + + if (qemu_in_coroutine()) { + bdrv_co_yield_to_drain(NULL, true, NULL, true); + return; + } + + bdrv_drain_all_begin_nopoll(); /* Now poll the in-flight requests */ AIO_WAIT_WHILE(NULL, bdrv_drain_all_poll()); -- 2.38.1 From: Paolo Bonzini <pbonzini@redhat.com> Block layer graph operations are always run under BQL in the main loop. This is proved by the assertion qemu_in_main_thread() and its wrapper macro GLOBAL_STATE_CODE. However, there are also concurrent coroutines running in other iothreads that always try to traverse the graph. Currently this is protected (among various other things) by the AioContext lock, but once this is removed, we need to make sure that reads do not happen while modifying the graph. We distinguish between writer (main loop, under BQL) that modifies the graph, and readers (all other coroutines running in various AioContext), that go through the graph edges, reading ->parents and->children. The writer (main loop) has "exclusive" access, so it first waits for any current read to finish, and then prevents incoming ones from entering while it has the exclusive access. The readers (coroutines in multiple AioContext) are free to access the graph as long the writer is not modifying the graph. In case it is, they go in a CoQueue and sleep until the writer is done. If a coroutine changes AioContext, the counter in the original and new AioContext are left intact, since the writer does not care where the reader is, but only if there is one. As a result, some AioContexts might have a negative reader count, to balance the positive count of the AioContext that took the lock. This also means that when an AioContext is deleted it may have a nonzero reader count. In that case we transfer the count to a global shared counter so that the writer is always aware of all readers. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-3-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/aio.h | 9 ++ include/block/block_int.h | 1 + include/block/graph-lock.h | 139 ++++++++++++++++++++ block/graph-lock.c | 261 +++++++++++++++++++++++++++++++++++++ block/meson.build | 1 + 5 files changed, 411 insertions(+) create mode 100644 include/block/graph-lock.h create mode 100644 block/graph-lock.c diff --git a/include/block/aio.h b/include/block/aio.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -XXX,XX +XXX,XX @@ #include "qemu/event_notifier.h" #include "qemu/thread.h" #include "qemu/timer.h" +#include "block/graph-lock.h" typedef struct BlockAIOCB BlockAIOCB; typedef void BlockCompletionFunc(void *opaque, int ret); @@ -XXX,XX +XXX,XX @@ struct AioContext { /* Used by AioContext users to protect from multi-threaded access. */ QemuRecMutex lock; + /* + * Keep track of readers and writers of the block layer graph. + * This is essential to avoid performing additions and removal + * of nodes and edges from block graph while some + * other thread is traversing it. + */ + BdrvGraphRWlock *bdrv_graph; + /* The list of registered AIO handlers. Protected by ctx->list_lock. */ AioHandlerList aio_handlers; diff --git a/include/block/block_int.h b/include/block/block_int.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -XXX,XX +XXX,XX @@ #include "block_int-global-state.h" #include "block_int-io.h" +#include "block/graph-lock.h" /* DO NOT ADD ANYTHING IN HERE. USE ONE OF THE HEADERS INCLUDED ABOVE */ diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/include/block/graph-lock.h @@ -XXX,XX +XXX,XX @@ +/* + * Graph lock: rwlock to protect block layer graph manipulations (add/remove + * edges and nodes) + * + * Copyright (c) 2022 Red Hat + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + */ +#ifndef GRAPH_LOCK_H +#define GRAPH_LOCK_H + +#include "qemu/osdep.h" + +#include "qemu/coroutine.h" + +/** + * Graph Lock API + * This API provides a rwlock used to protect block layer + * graph modifications like edge (BdrvChild) and node (BlockDriverState) + * addition and removal. + * Currently we have 1 writer only, the Main loop, and many + * readers, mostly coroutines running in other AioContext thus other threads. + * + * We distinguish between writer (main loop, under BQL) that modifies the + * graph, and readers (all other coroutines running in various AioContext), + * that go through the graph edges, reading + * BlockDriverState ->parents and->children. + * + * The writer (main loop) has an "exclusive" access, so it first waits for + * current read to finish, and then prevents incoming ones from + * entering while it has the exclusive access. + * + * The readers (coroutines in multiple AioContext) are free to + * access the graph as long the writer is not modifying the graph. + * In case it is, they go in a CoQueue and sleep until the writer + * is done. + * + * If a coroutine changes AioContext, the counter in the original and new + * AioContext are left intact, since the writer does not care where is the + * reader, but only if there is one. + * As a result, some AioContexts might have a negative reader count, to + * balance the positive count of the AioContext that took the lock. + * This also means that when an AioContext is deleted it may have a nonzero + * reader count. In that case we transfer the count to a global shared counter + * so that the writer is always aware of all readers. + */ +typedef struct BdrvGraphRWlock BdrvGraphRWlock; + +/* + * register_aiocontext: + * Add AioContext @ctx to the list of AioContext. + * This list is used to obtain the total number of readers + * currently running the graph. + */ +void register_aiocontext(AioContext *ctx); + +/* + * unregister_aiocontext: + * Removes AioContext @ctx to the list of AioContext. + */ +void unregister_aiocontext(AioContext *ctx); + +/* + * bdrv_graph_wrlock: + * Start an exclusive write operation to modify the graph. This means we are + * adding or removing an edge or a node in the block layer graph. Nobody else + * is allowed to access the graph. + * + * Must only be called from outside bdrv_graph_co_rdlock. + * + * The wrlock can only be taken from the main loop, with BQL held, as only the + * main loop is allowed to modify the graph. + * + * This function polls. Callers must not hold the lock of any AioContext other + * than the current one. + */ +void bdrv_graph_wrlock(void); + +/* + * bdrv_graph_wrunlock: + * Write finished, reset global has_writer to 0 and restart + * all readers that are waiting. + */ +void bdrv_graph_wrunlock(void); + +/* + * bdrv_graph_co_rdlock: + * Read the bs graph. This usually means traversing all nodes in + * the graph, therefore it can't happen while another thread is + * modifying it. + * Increases the reader counter of the current aiocontext, + * and if has_writer is set, it means that the writer is modifying + * the graph, therefore wait in a coroutine queue. + * The writer will then wake this coroutine once it is done. + * + * This lock should be taken from Iothreads (IO_CODE() class of functions) + * because it signals the writer that there are some + * readers currently running, or waits until the current + * write is finished before continuing. + * Calling this function from the Main Loop with BQL held + * is not necessary, since the Main Loop itself is the only + * writer, thus won't be able to read and write at the same time. + * The only exception to that is when we can't take the lock in the + * function/coroutine itself, and need to delegate the caller (usually main + * loop) to take it and wait that the coroutine ends, so that + * we always signal that a reader is running. + */ +void coroutine_fn bdrv_graph_co_rdlock(void); + +/* + * bdrv_graph_rdunlock: + * Read terminated, decrease the count of readers in the current aiocontext. + * If the writer is waiting for reads to finish (has_writer == 1), signal + * the writer that we are done via aio_wait_kick() to let it continue. + */ +void coroutine_fn bdrv_graph_co_rdunlock(void); + +/* + * bdrv_graph_rd{un}lock_main_loop: + * Just a placeholder to mark where the graph rdlock should be taken + * in the main loop. It is just asserting that we are not + * in a coroutine and in GLOBAL_STATE_CODE. + */ +void bdrv_graph_rdlock_main_loop(void); +void bdrv_graph_rdunlock_main_loop(void); + +#endif /* GRAPH_LOCK_H */ + diff --git a/block/graph-lock.c b/block/graph-lock.c new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/block/graph-lock.c @@ -XXX,XX +XXX,XX @@ +/* + * Graph lock: rwlock to protect block layer graph manipulations (add/remove + * edges and nodes) + * + * Copyright (c) 2022 Red Hat + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + */ + +#include "qemu/osdep.h" +#include "qemu/main-loop.h" +#include "block/graph-lock.h" +#include "block/block.h" +#include "block/block_int.h" + +/* Protects the list of aiocontext and orphaned_reader_count */ +static QemuMutex aio_context_list_lock; + +/* Written and read with atomic operations. */ +static int has_writer; + +/* + * A reader coroutine could move from an AioContext to another. + * If this happens, there is no problem from the point of view of + * counters. The problem is that the total count becomes + * unbalanced if one of the two AioContexts gets deleted. + * The count of readers must remain correct, so the AioContext's + * balance is transferred to this glboal variable. + * Protected by aio_context_list_lock. + */ +static uint32_t orphaned_reader_count; + +/* Queue of readers waiting for the writer to finish */ +static CoQueue reader_queue; + +struct BdrvGraphRWlock { + /* How many readers are currently reading the graph. */ + uint32_t reader_count; + + /* + * List of BdrvGraphRWlock kept in graph-lock.c + * Protected by aio_context_list_lock + */ + QTAILQ_ENTRY(BdrvGraphRWlock) next_aio; +}; + +/* + * List of BdrvGraphRWlock. This list ensures that each BdrvGraphRWlock + * can safely modify only its own counter, avoid reading/writing + * others and thus improving performances by avoiding cacheline bounces. + */ +static QTAILQ_HEAD(, BdrvGraphRWlock) aio_context_list = + QTAILQ_HEAD_INITIALIZER(aio_context_list); + +static void __attribute__((__constructor__)) bdrv_init_graph_lock(void) +{ + qemu_mutex_init(&aio_context_list_lock); + qemu_co_queue_init(&reader_queue); +} + +void register_aiocontext(AioContext *ctx) +{ + ctx->bdrv_graph = g_new0(BdrvGraphRWlock, 1); + QEMU_LOCK_GUARD(&aio_context_list_lock); + assert(ctx->bdrv_graph->reader_count == 0); + QTAILQ_INSERT_TAIL(&aio_context_list, ctx->bdrv_graph, next_aio); +} + +void unregister_aiocontext(AioContext *ctx) +{ + QEMU_LOCK_GUARD(&aio_context_list_lock); + orphaned_reader_count += ctx->bdrv_graph->reader_count; + QTAILQ_REMOVE(&aio_context_list, ctx->bdrv_graph, next_aio); + g_free(ctx->bdrv_graph); +} + +static uint32_t reader_count(void) +{ + BdrvGraphRWlock *brdv_graph; + uint32_t rd; + + QEMU_LOCK_GUARD(&aio_context_list_lock); + + /* rd can temporarly be negative, but the total will *always* be >= 0 */ + rd = orphaned_reader_count; + QTAILQ_FOREACH(brdv_graph, &aio_context_list, next_aio) { + rd += qatomic_read(&brdv_graph->reader_count); + } + + /* shouldn't overflow unless there are 2^31 readers */ + assert((int32_t)rd >= 0); + return rd; +} + +void bdrv_graph_wrlock(void) +{ + GLOBAL_STATE_CODE(); + assert(!qatomic_read(&has_writer)); + + /* Make sure that constantly arriving new I/O doesn't cause starvation */ + bdrv_drain_all_begin_nopoll(); + + /* + * reader_count == 0: this means writer will read has_reader as 1 + * reader_count >= 1: we don't know if writer read has_writer == 0 or 1, + * but we need to wait. + * Wait by allowing other coroutine (and possible readers) to continue. + */ + do { + /* + * has_writer must be 0 while polling, otherwise we get a deadlock if + * any callback involved during AIO_WAIT_WHILE() tries to acquire the + * reader lock. + */ + qatomic_set(&has_writer, 0); + AIO_WAIT_WHILE(qemu_get_aio_context(), reader_count() >= 1); + qatomic_set(&has_writer, 1); + + /* + * We want to only check reader_count() after has_writer = 1 is visible + * to other threads. That way no more readers can sneak in after we've + * determined reader_count() == 0. + */ + smp_mb(); + } while (reader_count() >= 1); + + bdrv_drain_all_end(); +} + +void bdrv_graph_wrunlock(void) +{ + GLOBAL_STATE_CODE(); + QEMU_LOCK_GUARD(&aio_context_list_lock); + assert(qatomic_read(&has_writer)); + + /* + * No need for memory barriers, this works in pair with + * the slow path of rdlock() and both take the lock. + */ + qatomic_store_release(&has_writer, 0); + + /* Wake up all coroutine that are waiting to read the graph */ + qemu_co_enter_all(&reader_queue, &aio_context_list_lock); +} + +void coroutine_fn bdrv_graph_co_rdlock(void) +{ + BdrvGraphRWlock *bdrv_graph; + bdrv_graph = qemu_get_current_aio_context()->bdrv_graph; + + /* Do not lock if in main thread */ + if (qemu_in_main_thread()) { + return; + } + + for (;;) { + qatomic_set(&bdrv_graph->reader_count, + bdrv_graph->reader_count + 1); + /* make sure writer sees reader_count before we check has_writer */ + smp_mb(); + + /* + * has_writer == 0: this means writer will read reader_count as >= 1 + * has_writer == 1: we don't know if writer read reader_count == 0 + * or > 0, but we need to wait anyways because + * it will write. + */ + if (!qatomic_read(&has_writer)) { + break; + } + + /* + * Synchronize access with reader_count() in bdrv_graph_wrlock(). + * Case 1: + * If this critical section gets executed first, reader_count will + * decrease and the reader will go to sleep. + * Then the writer will read reader_count that does not take into + * account this reader, and if there's no other reader it will + * enter the write section. + * Case 2: + * If reader_count() critical section gets executed first, + * then writer will read reader_count >= 1. + * It will wait in AIO_WAIT_WHILE(), but once it releases the lock + * we will enter this critical section and call aio_wait_kick(). + */ + WITH_QEMU_LOCK_GUARD(&aio_context_list_lock) { + /* + * Additional check when we use the above lock to synchronize + * with bdrv_graph_wrunlock(). + * Case 1: + * If this gets executed first, has_writer is still 1, so we reduce + * reader_count and go to sleep. + * Then the writer will set has_writer to 0 and wake up all readers, + * us included. + * Case 2: + * If bdrv_graph_wrunlock() critical section gets executed first, + * then it will set has_writer to 0 and wake up all other readers. + * Then we execute this critical section, and therefore must check + * again for has_writer, otherwise we sleep without any writer + * actually running. + */ + if (!qatomic_read(&has_writer)) { + return; + } + + /* slow path where reader sleeps */ + bdrv_graph->reader_count--; + aio_wait_kick(); + qemu_co_queue_wait(&reader_queue, &aio_context_list_lock); + } + } +} + +void coroutine_fn bdrv_graph_co_rdunlock(void) +{ + BdrvGraphRWlock *bdrv_graph; + bdrv_graph = qemu_get_current_aio_context()->bdrv_graph; + + /* Do not lock if in main thread */ + if (qemu_in_main_thread()) { + return; + } + + qatomic_store_release(&bdrv_graph->reader_count, + bdrv_graph->reader_count - 1); + /* make sure writer sees reader_count before we check has_writer */ + smp_mb(); + + /* + * has_writer == 0: this means reader will read reader_count decreased + * has_writer == 1: we don't know if writer read reader_count old or + * new. Therefore, kick again so on next iteration + * writer will for sure read the updated value. + */ + if (qatomic_read(&has_writer)) { + aio_wait_kick(); + } +} + +void bdrv_graph_rdlock_main_loop(void) +{ + GLOBAL_STATE_CODE(); + assert(!qemu_in_coroutine()); +} + +void bdrv_graph_rdunlock_main_loop(void) +{ + GLOBAL_STATE_CODE(); + assert(!qemu_in_coroutine()); +} diff --git a/block/meson.build b/block/meson.build index XXXXXXX..XXXXXXX 100644 --- a/block/meson.build +++ b/block/meson.build @@ -XXX,XX +XXX,XX @@ block_ss.add(files( 'blkverify.c', 'block-backend.c', 'block-copy.c', + 'graph-lock.c', 'commit.c', 'copy-on-read.c', 'preallocate.c', -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> Similar to the implementation in lockable.h, implement macros to automatically take and release the rdlock. Create the empty GraphLockable and GraphLockableMainloop structs only to use it as a type for G_DEFINE_AUTOPTR_CLEANUP_FUNC. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-4-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/graph-lock.h | 66 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/graph-lock.h +++ b/include/block/graph-lock.h @@ -XXX,XX +XXX,XX @@ void coroutine_fn bdrv_graph_co_rdunlock(void); void bdrv_graph_rdlock_main_loop(void); void bdrv_graph_rdunlock_main_loop(void); +typedef struct GraphLockable { } GraphLockable; + +/* + * In C, compound literals have the lifetime of an automatic variable. + * In C++ it would be different, but then C++ wouldn't need QemuLockable + * either... + */ +#define GML_OBJ_() (&(GraphLockable) { }) + +static inline GraphLockable *graph_lockable_auto_lock(GraphLockable *x) +{ + bdrv_graph_co_rdlock(); + return x; +} + +static inline void graph_lockable_auto_unlock(GraphLockable *x) +{ + bdrv_graph_co_rdunlock(); +} + +G_DEFINE_AUTOPTR_CLEANUP_FUNC(GraphLockable, graph_lockable_auto_unlock) + +#define WITH_GRAPH_RDLOCK_GUARD_(var) \ + for (g_autoptr(GraphLockable) var = graph_lockable_auto_lock(GML_OBJ_()); \ + var; \ + graph_lockable_auto_unlock(var), var = NULL) + +#define WITH_GRAPH_RDLOCK_GUARD() \ + WITH_GRAPH_RDLOCK_GUARD_(glue(graph_lockable_auto, __COUNTER__)) + +#define GRAPH_RDLOCK_GUARD(x) \ + g_autoptr(GraphLockable) \ + glue(graph_lockable_auto, __COUNTER__) G_GNUC_UNUSED = \ + graph_lockable_auto_lock(GML_OBJ_()) + + +typedef struct GraphLockableMainloop { } GraphLockableMainloop; + +/* + * In C, compound literals have the lifetime of an automatic variable. + * In C++ it would be different, but then C++ wouldn't need QemuLockable + * either... + */ +#define GMLML_OBJ_() (&(GraphLockableMainloop) { }) + +static inline GraphLockableMainloop * +graph_lockable_auto_lock_mainloop(GraphLockableMainloop *x) +{ + bdrv_graph_rdlock_main_loop(); + return x; +} + +static inline void +graph_lockable_auto_unlock_mainloop(GraphLockableMainloop *x) +{ + bdrv_graph_rdunlock_main_loop(); +} + +G_DEFINE_AUTOPTR_CLEANUP_FUNC(GraphLockableMainloop, + graph_lockable_auto_unlock_mainloop) + +#define GRAPH_RDLOCK_GUARD_MAINLOOP(x) \ + g_autoptr(GraphLockableMainloop) \ + glue(graph_lockable_auto, __COUNTER__) G_GNUC_UNUSED = \ + graph_lockable_auto_lock_mainloop(GMLML_OBJ_()) + #endif /* GRAPH_LOCK_H */ -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> Add/remove the AioContext in aio_context_list in graph-lock.c when it is created/destroyed. This allows using the graph locking operations from this AioContext. In order to allow linking util/async.c with binaries that don't include the block layer, introduce stubs for (un)register_aiocontext(). Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-5-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- stubs/graph-lock.c | 10 ++++++++++ util/async.c | 4 ++++ stubs/meson.build | 1 + 3 files changed, 15 insertions(+) create mode 100644 stubs/graph-lock.c diff --git a/stubs/graph-lock.c b/stubs/graph-lock.c new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/stubs/graph-lock.c @@ -XXX,XX +XXX,XX @@ +#include "qemu/osdep.h" +#include "block/graph-lock.h" + +void register_aiocontext(AioContext *ctx) +{ +} + +void unregister_aiocontext(AioContext *ctx) +{ +} diff --git a/util/async.c b/util/async.c index XXXXXXX..XXXXXXX 100644 --- a/util/async.c +++ b/util/async.c @@ -XXX,XX +XXX,XX @@ #include "qapi/error.h" #include "block/aio.h" #include "block/thread-pool.h" +#include "block/graph-lock.h" #include "qemu/main-loop.h" #include "qemu/atomic.h" #include "qemu/rcu_queue.h" @@ -XXX,XX +XXX,XX @@ aio_ctx_finalize(GSource *source) qemu_rec_mutex_destroy(&ctx->lock); qemu_lockcnt_destroy(&ctx->list_lock); timerlistgroup_deinit(&ctx->tlg); + unregister_aiocontext(ctx); aio_context_destroy(ctx); } @@ -XXX,XX +XXX,XX @@ AioContext *aio_context_new(Error **errp) ctx->thread_pool_min = 0; ctx->thread_pool_max = THREAD_POOL_MAX_THREADS_DEFAULT; + register_aiocontext(ctx); + return ctx; fail: g_source_destroy(&ctx->source); diff --git a/stubs/meson.build b/stubs/meson.build index XXXXXXX..XXXXXXX 100644 --- a/stubs/meson.build +++ b/stubs/meson.build @@ -XXX,XX +XXX,XX @@ stub_ss.add(files('error-printf.c')) stub_ss.add(files('fdset.c')) stub_ss.add(files('gdbstub.c')) stub_ss.add(files('get-vm-name.c')) +stub_ss.add(files('graph-lock.c')) if linux_io_uring.found() stub_ss.add(files('io_uring.c')) endif -- 2.38.1 This defines macros that allow clang to perform Thread Safety Analysis based on function and variable annotations that specify the locking rules. On non-clang compilers, the annotations are ignored. Imported tsa.h from the original repository with the pthread_mutex_t wrapper removed: https://github.com/jhi/clang-thread-safety-analysis-for-c.git Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-6-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/qemu/clang-tsa.h | 101 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 include/qemu/clang-tsa.h diff --git a/include/qemu/clang-tsa.h b/include/qemu/clang-tsa.h new file mode 100644 index XXXXXXX..XXXXXXX --- /dev/null +++ b/include/qemu/clang-tsa.h @@ -XXX,XX +XXX,XX @@ +#ifndef CLANG_TSA_H +#define CLANG_TSA_H + +/* + * Copyright 2018 Jarkko Hietaniemi <jhi@iki.fi> + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without + * limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY + * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, + * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE + * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +/* http://clang.llvm.org/docs/ThreadSafetyAnalysis.html + * + * TSA is available since clang 3.6-ish. + */ +#ifdef __clang__ +# define TSA(x) __attribute__((x)) +#else +# define TSA(x) /* No TSA, make TSA attributes no-ops. */ +#endif + +/* TSA_CAPABILITY() is used to annotate typedefs: + * + * typedef pthread_mutex_t TSA_CAPABILITY("mutex") tsa_mutex; + */ +#define TSA_CAPABILITY(x) TSA(capability(x)) + +/* TSA_GUARDED_BY() is used to annotate global variables, + * the data is guarded: + * + * Foo foo TSA_GUARDED_BY(mutex); + */ +#define TSA_GUARDED_BY(x) TSA(guarded_by(x)) + +/* TSA_PT_GUARDED_BY() is used to annotate global pointers, the data + * behind the pointer is guarded. + * + * Foo* ptr TSA_PT_GUARDED_BY(mutex); + */ +#define TSA_PT_GUARDED_BY(x) TSA(pt_guarded_by(x)) + +/* The TSA_REQUIRES() is used to annotate functions: the caller of the + * function MUST hold the resource, the function will NOT release it. + * + * More than one mutex may be specified, comma-separated. + * + * void Foo(void) TSA_REQUIRES(mutex); + */ +#define TSA_REQUIRES(...) TSA(requires_capability(__VA_ARGS__)) + +/* TSA_EXCLUDES() is used to annotate functions: the caller of the + * function MUST NOT hold resource, the function first acquires the + * resource, and then releases it. + * + * More than one mutex may be specified, comma-separated. + * + * void Foo(void) TSA_EXCLUDES(mutex); + */ +#define TSA_EXCLUDES(...) TSA(locks_excluded(__VA_ARGS__)) + +/* TSA_ACQUIRE() is used to annotate functions: the caller of the + * function MUST NOT hold the resource, the function will acquire the + * resource, but NOT release it. + * + * More than one mutex may be specified, comma-separated. + * + * void Foo(void) TSA_ACQUIRE(mutex); + */ +#define TSA_ACQUIRE(...) TSA(acquire_capability(__VA_ARGS__)) + +/* TSA_RELEASE() is used to annotate functions: the caller of the + * function MUST hold the resource, but the function will then release it. + * + * More than one mutex may be specified, comma-separated. + * + * void Foo(void) TSA_RELEASE(mutex); + */ +#define TSA_RELEASE(...) TSA(release_capability(__VA_ARGS__)) + +/* TSA_NO_TSA is used to annotate functions. Use only when you need to. + * + * void Foo(void) TSA_NO_TSA; + */ +#define TSA_NO_TSA TSA(no_thread_safety_analysis) + +#endif /* #ifndef CLANG_TSA_H */ -- 2.38.1 Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-7-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/qemu/clang-tsa.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/include/qemu/clang-tsa.h b/include/qemu/clang-tsa.h index XXXXXXX..XXXXXXX 100644 --- a/include/qemu/clang-tsa.h +++ b/include/qemu/clang-tsa.h @@ -XXX,XX +XXX,XX @@ */ #define TSA_NO_TSA TSA(no_thread_safety_analysis) +/* + * TSA_ASSERT() is used to annotate functions: This function will assert that + * the lock is held. When it returns, the caller of the function is assumed to + * already hold the resource. + * + * More than one mutex may be specified, comma-separated. + */ +#define TSA_ASSERT(...) TSA(assert_capability(__VA_ARGS__)) + #endif /* #ifndef CLANG_TSA_H */ -- 2.38.1 Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-8-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/qemu/clang-tsa.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/qemu/clang-tsa.h b/include/qemu/clang-tsa.h index XXXXXXX..XXXXXXX 100644 --- a/include/qemu/clang-tsa.h +++ b/include/qemu/clang-tsa.h @@ -XXX,XX +XXX,XX @@ * void Foo(void) TSA_REQUIRES(mutex); */ #define TSA_REQUIRES(...) TSA(requires_capability(__VA_ARGS__)) +#define TSA_REQUIRES_SHARED(...) TSA(requires_shared_capability(__VA_ARGS__)) /* TSA_EXCLUDES() is used to annotate functions: the caller of the * function MUST NOT hold resource, the function first acquires the @@ -XXX,XX +XXX,XX @@ * void Foo(void) TSA_ACQUIRE(mutex); */ #define TSA_ACQUIRE(...) TSA(acquire_capability(__VA_ARGS__)) +#define TSA_ACQUIRE_SHARED(...) TSA(acquire_shared_capability(__VA_ARGS__)) /* TSA_RELEASE() is used to annotate functions: the caller of the * function MUST hold the resource, but the function will then release it. @@ -XXX,XX +XXX,XX @@ * void Foo(void) TSA_RELEASE(mutex); */ #define TSA_RELEASE(...) TSA(release_capability(__VA_ARGS__)) +#define TSA_RELEASE_SHARED(...) TSA(release_shared_capability(__VA_ARGS__)) /* TSA_NO_TSA is used to annotate functions. Use only when you need to. * @@ -XXX,XX +XXX,XX @@ * More than one mutex may be specified, comma-separated. */ #define TSA_ASSERT(...) TSA(assert_capability(__VA_ARGS__)) +#define TSA_ASSERT_SHARED(...) TSA(assert_shared_capability(__VA_ARGS__)) #endif /* #ifndef CLANG_TSA_H */ -- 2.38.1 This enables clang's thread safety analysis (TSA), which we'll use to statically check the block graph locking. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-9-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- configure | 1 + 1 file changed, 1 insertion(+) diff --git a/configure b/configure index XXXXXXX..XXXXXXX 100755 --- a/configure +++ b/configure @@ -XXX,XX +XXX,XX @@ add_to warn_flags -Wnested-externs add_to warn_flags -Wendif-labels add_to warn_flags -Wexpansion-to-defined add_to warn_flags -Wimplicit-fallthrough=2 +add_to warn_flags -Wthread-safety nowarn_flags= add_to nowarn_flags -Wno-initializer-overrides -- 2.38.1 The test case assumes that a drain only happens in one specific place where it drains explicitly. This assumption happened to hold true until now, but block layer functions may drain interally (any graph modifications are going to do that through bdrv_graph_wrlock()), so this is incorrect. Make sure that the test code in .drained_begin only runs where we actually want it to run. When scheduling a BH from .drained_begin, we also need to increase the in_flight counter to make sure that the operation is actually completed in time before the node that it works on goes away. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-10-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- tests/unit/test-bdrv-drain.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c index XXXXXXX..XXXXXXX 100644 --- a/tests/unit/test-bdrv-drain.c +++ b/tests/unit/test-bdrv-drain.c @@ -XXX,XX +XXX,XX @@ struct detach_by_parent_data { BlockDriverState *c; BdrvChild *child_c; bool by_parent_cb; + bool detach_on_drain; }; static struct detach_by_parent_data detach_by_parent_data; @@ -XXX,XX +XXX,XX @@ static void detach_indirect_bh(void *opaque) { struct detach_by_parent_data *data = opaque; + bdrv_dec_in_flight(data->child_b->bs); bdrv_unref_child(data->parent_b, data->child_b); bdrv_ref(data->c); @@ -XXX,XX +XXX,XX @@ static void detach_by_parent_aio_cb(void *opaque, int ret) g_assert_cmpint(ret, ==, 0); if (data->by_parent_cb) { + bdrv_inc_in_flight(data->child_b->bs); detach_indirect_bh(data); } } static void detach_by_driver_cb_drained_begin(BdrvChild *child) { + struct detach_by_parent_data *data = &detach_by_parent_data; + + if (!data->detach_on_drain) { + return; + } + data->detach_on_drain = false; + + bdrv_inc_in_flight(data->child_b->bs); aio_bh_schedule_oneshot(qemu_get_current_aio_context(), detach_indirect_bh, &detach_by_parent_data); child_of_bds.drained_begin(child); @@ -XXX,XX +XXX,XX @@ static void test_detach_indirect(bool by_parent_cb) detach_by_driver_cb_class = child_of_bds; detach_by_driver_cb_class.drained_begin = detach_by_driver_cb_drained_begin; + detach_by_driver_cb_class.drained_end = NULL; + detach_by_driver_cb_class.drained_poll = NULL; } + detach_by_parent_data = (struct detach_by_parent_data) { + .detach_on_drain = false, + }; + /* Create all involved nodes */ parent_a = bdrv_new_open_driver(&bdrv_test, "parent-a", BDRV_O_RDWR, &error_abort); @@ -XXX,XX +XXX,XX @@ static void test_detach_indirect(bool by_parent_cb) .child_b = child_b, .c = c, .by_parent_cb = by_parent_cb, + .detach_on_drain = true, }; acb = blk_aio_preadv(blk, 0, &qiov, 0, detach_by_parent_aio_cb, NULL); g_assert(acb != NULL); -- 2.38.1 bdrv_img_create() polls internally (when calling bdrv_create(), which is a co_wrapper), so it can't be called while holding the lock of any AioContext except the current one without causing deadlocks. Drop the lock around the call in external_snapshot_prepare(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-11-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 4 ++++ blockdev.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ bool bdrv_op_blocker_is_empty(BlockDriverState *bs) return true; } +/* + * Must not be called while holding the lock of an AioContext other than the + * current one. + */ void bdrv_img_create(const char *filename, const char *fmt, const char *base_filename, const char *base_fmt, char *options, uint64_t img_size, int flags, bool quiet, diff --git a/blockdev.c b/blockdev.c index XXXXXXX..XXXXXXX 100644 --- a/blockdev.c +++ b/blockdev.c @@ -XXX,XX +XXX,XX @@ static void external_snapshot_prepare(BlkActionState *common, goto out; } bdrv_refresh_filename(state->old_bs); + + aio_context_release(aio_context); bdrv_img_create(new_image_file, format, state->old_bs->filename, state->old_bs->drv->format_name, NULL, size, flags, false, &local_err); + aio_context_acquire(aio_context); + if (local_err) { error_propagate(errp, local_err); goto out; -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> Protect the main function where graph is modified. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-12-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm) * * If @new_bs is non-NULL, the parent of @child must already be drained through * @child. - * - * This function does not poll. */ static void bdrv_replace_child_noperm(BdrvChild *child, BlockDriverState *new_bs) @@ -XXX,XX +XXX,XX @@ static void bdrv_replace_child_noperm(BdrvChild *child, assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs)); } + /* TODO Pull this up into the callers to avoid polling here */ + bdrv_graph_wrlock(); if (old_bs) { if (child->klass->detach) { child->klass->detach(child); } - assert_bdrv_graph_writable(old_bs); QLIST_REMOVE(child, next_parent); } child->bs = new_bs; if (new_bs) { - assert_bdrv_graph_writable(new_bs); QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); if (child->klass->attach) { child->klass->attach(child); } } + bdrv_graph_wrunlock(); /* * If the parent was drained through this BdrvChild previously, but new_bs -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> We don't protect bdrv->aio_context with the graph rwlock, so these assertions are not needed Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-13-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static void bdrv_detach_aio_context(BlockDriverState *bs) if (bs->quiesce_counter) { aio_enable_external(bs->aio_context); } - assert_bdrv_graph_writable(bs); bs->aio_context = NULL; } @@ -XXX,XX +XXX,XX @@ static void bdrv_attach_aio_context(BlockDriverState *bs, aio_disable_external(new_context); } - assert_bdrv_graph_writable(bs); bs->aio_context = new_context; if (bs->drv && bs->drv->bdrv_attach_aio_context) { @@ -XXX,XX +XXX,XX @@ static void bdrv_set_aio_context_commit(void *opaque) BlockDriverState *bs = (BlockDriverState *) state->bs; AioContext *new_context = state->new_ctx; AioContext *old_context = bdrv_get_aio_context(bs); - assert_bdrv_graph_writable(bs); /* * Take the old AioContex when detaching it from bs. -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> Remove the old assert_bdrv_graph_writable, and replace it with the new version using graph-lock API. See the function documentation for more information. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-14-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block_int-global-state.h | 17 ----------------- include/block/graph-lock.h | 15 +++++++++++++++ block.c | 4 ++-- block/graph-lock.c | 11 +++++++++++ 4 files changed, 28 insertions(+), 19 deletions(-) diff --git a/include/block/block_int-global-state.h b/include/block/block_int-global-state.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int-global-state.h +++ b/include/block/block_int-global-state.h @@ -XXX,XX +XXX,XX @@ void bdrv_remove_aio_context_notifier(BlockDriverState *bs, */ void bdrv_drain_all_end_quiesce(BlockDriverState *bs); -/** - * Make sure that the function is running under both drain and BQL. - * The latter protects from concurrent writings - * from the GS API, while the former prevents concurrent reads - * from I/O. - */ -static inline void assert_bdrv_graph_writable(BlockDriverState *bs) -{ - /* - * TODO: this function is incomplete. Because the users of this - * assert lack the necessary drains, check only for BQL. - * Once the necessary drains are added, - * assert also for qatomic_read(&bs->quiesce_counter) > 0 - */ - assert(qemu_in_main_thread()); -} - #endif /* BLOCK_INT_GLOBAL_STATE_H */ diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/graph-lock.h +++ b/include/block/graph-lock.h @@ -XXX,XX +XXX,XX @@ void coroutine_fn bdrv_graph_co_rdunlock(void); void bdrv_graph_rdlock_main_loop(void); void bdrv_graph_rdunlock_main_loop(void); +/* + * assert_bdrv_graph_readable: + * Make sure that the reader is either the main loop, + * or there is at least a reader helding the rdlock. + * In this way an incoming writer is aware of the read and waits. + */ +void assert_bdrv_graph_readable(void); + +/* + * assert_bdrv_graph_writable: + * Make sure that the writer is the main loop and has set @has_writer, + * so that incoming readers will pause. + */ +void assert_bdrv_graph_writable(void); + typedef struct GraphLockable { } GraphLockable; /* diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static void bdrv_child_cb_attach(BdrvChild *child) { BlockDriverState *bs = child->opaque; - assert_bdrv_graph_writable(bs); + assert_bdrv_graph_writable(); QLIST_INSERT_HEAD(&bs->children, child, next); if (bs->drv->is_filter || (child->role & BDRV_CHILD_FILTERED)) { /* @@ -XXX,XX +XXX,XX @@ static void bdrv_child_cb_detach(BdrvChild *child) bdrv_backing_detach(child); } - assert_bdrv_graph_writable(bs); + assert_bdrv_graph_writable(); QLIST_REMOVE(child, next); if (child == bs->backing) { assert(child != bs->file); diff --git a/block/graph-lock.c b/block/graph-lock.c index XXXXXXX..XXXXXXX 100644 --- a/block/graph-lock.c +++ b/block/graph-lock.c @@ -XXX,XX +XXX,XX @@ void bdrv_graph_rdunlock_main_loop(void) GLOBAL_STATE_CODE(); assert(!qemu_in_coroutine()); } + +void assert_bdrv_graph_readable(void) +{ + assert(qemu_in_main_thread() || reader_count()); +} + +void assert_bdrv_graph_writable(void) +{ + assert(qemu_in_main_thread()); + assert(qatomic_read(&has_writer)); +} -- 2.38.1 Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-15-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/graph-lock.h | 80 +++++++++++++++++++++++++++++++++----- block/graph-lock.c | 3 ++ 2 files changed, 73 insertions(+), 10 deletions(-) diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/graph-lock.h +++ b/include/block/graph-lock.h @@ -XXX,XX +XXX,XX @@ #define GRAPH_LOCK_H #include "qemu/osdep.h" +#include "qemu/clang-tsa.h" #include "qemu/coroutine.h" @@ -XXX,XX +XXX,XX @@ */ typedef struct BdrvGraphRWlock BdrvGraphRWlock; +/* Dummy lock object to use for Thread Safety Analysis (TSA) */ +typedef struct TSA_CAPABILITY("graph-lock") BdrvGraphLock { +} BdrvGraphLock; + +extern BdrvGraphLock graph_lock; + +/* + * clang doesn't check consistency in locking annotations between forward + * declarations and the function definition. Having the annotation on the + * definition, but not the declaration in a header file, may give the reader + * a false sense of security because the condition actually remains unchecked + * for callers in other source files. + * + * Therefore, as a convention, for public functions, GRAPH_RDLOCK and + * GRAPH_WRLOCK annotations should be present only in the header file. + */ +#define GRAPH_WRLOCK TSA_REQUIRES(graph_lock) +#define GRAPH_RDLOCK TSA_REQUIRES_SHARED(graph_lock) + +/* + * TSA annotations are not part of function types, so checks are defeated when + * using a function pointer. As a workaround, annotate function pointers with + * this macro that will require that the lock is at least taken while reading + * the pointer. In most cases this is equivalent to actually protecting the + * function call. + */ +#define GRAPH_RDLOCK_PTR TSA_GUARDED_BY(graph_lock) +#define GRAPH_WRLOCK_PTR TSA_GUARDED_BY(graph_lock) + /* * register_aiocontext: * Add AioContext @ctx to the list of AioContext. @@ -XXX,XX +XXX,XX @@ void unregister_aiocontext(AioContext *ctx); * This function polls. Callers must not hold the lock of any AioContext other * than the current one. */ -void bdrv_graph_wrlock(void); +void bdrv_graph_wrlock(void) TSA_ACQUIRE(graph_lock) TSA_NO_TSA; /* * bdrv_graph_wrunlock: * Write finished, reset global has_writer to 0 and restart * all readers that are waiting. */ -void bdrv_graph_wrunlock(void); +void bdrv_graph_wrunlock(void) TSA_RELEASE(graph_lock) TSA_NO_TSA; /* * bdrv_graph_co_rdlock: @@ -XXX,XX +XXX,XX @@ void bdrv_graph_wrunlock(void); * loop) to take it and wait that the coroutine ends, so that * we always signal that a reader is running. */ -void coroutine_fn bdrv_graph_co_rdlock(void); +void coroutine_fn TSA_ACQUIRE_SHARED(graph_lock) TSA_NO_TSA +bdrv_graph_co_rdlock(void); /* * bdrv_graph_rdunlock: @@ -XXX,XX +XXX,XX @@ void coroutine_fn bdrv_graph_co_rdlock(void); * If the writer is waiting for reads to finish (has_writer == 1), signal * the writer that we are done via aio_wait_kick() to let it continue. */ -void coroutine_fn bdrv_graph_co_rdunlock(void); +void coroutine_fn TSA_RELEASE_SHARED(graph_lock) TSA_NO_TSA +bdrv_graph_co_rdunlock(void); /* * bdrv_graph_rd{un}lock_main_loop: @@ -XXX,XX +XXX,XX @@ void coroutine_fn bdrv_graph_co_rdunlock(void); * in the main loop. It is just asserting that we are not * in a coroutine and in GLOBAL_STATE_CODE. */ -void bdrv_graph_rdlock_main_loop(void); -void bdrv_graph_rdunlock_main_loop(void); +void TSA_ACQUIRE_SHARED(graph_lock) TSA_NO_TSA +bdrv_graph_rdlock_main_loop(void); + +void TSA_RELEASE_SHARED(graph_lock) TSA_NO_TSA +bdrv_graph_rdunlock_main_loop(void); /* * assert_bdrv_graph_readable: @@ -XXX,XX +XXX,XX @@ void assert_bdrv_graph_readable(void); */ void assert_bdrv_graph_writable(void); +/* + * Calling this function tells TSA that we know that the lock is effectively + * taken even though we cannot prove it (yet) with GRAPH_RDLOCK. This can be + * useful in intermediate stages of a conversion to using the GRAPH_RDLOCK + * macro. + */ +static inline void TSA_ASSERT_SHARED(graph_lock) TSA_NO_TSA +assume_graph_lock(void) +{ +} + typedef struct GraphLockable { } GraphLockable; /* @@ -XXX,XX +XXX,XX @@ typedef struct GraphLockable { } GraphLockable; */ #define GML_OBJ_() (&(GraphLockable) { }) -static inline GraphLockable *graph_lockable_auto_lock(GraphLockable *x) +/* + * This is not marked as TSA_ACQUIRE() because TSA doesn't understand the + * cleanup attribute and would therefore complain that the graph is never + * unlocked. TSA_ASSERT() makes sure that the following calls know that we + * hold the lock while unlocking is left unchecked. + */ +static inline GraphLockable * TSA_ASSERT(graph_lock) TSA_NO_TSA +graph_lockable_auto_lock(GraphLockable *x) { bdrv_graph_co_rdlock(); return x; } -static inline void graph_lockable_auto_unlock(GraphLockable *x) +static inline void TSA_NO_TSA +graph_lockable_auto_unlock(GraphLockable *x) { bdrv_graph_co_rdunlock(); } @@ -XXX,XX +XXX,XX @@ typedef struct GraphLockableMainloop { } GraphLockableMainloop; */ #define GMLML_OBJ_() (&(GraphLockableMainloop) { }) -static inline GraphLockableMainloop * +/* + * This is not marked as TSA_ACQUIRE() because TSA doesn't understand the + * cleanup attribute and would therefore complain that the graph is never + * unlocked. TSA_ASSERT() makes sure that the following calls know that we + * hold the lock while unlocking is left unchecked. + */ +static inline GraphLockableMainloop * TSA_ASSERT(graph_lock) TSA_NO_TSA graph_lockable_auto_lock_mainloop(GraphLockableMainloop *x) { bdrv_graph_rdlock_main_loop(); return x; } -static inline void +static inline void TSA_NO_TSA graph_lockable_auto_unlock_mainloop(GraphLockableMainloop *x) { bdrv_graph_rdunlock_main_loop(); diff --git a/block/graph-lock.c b/block/graph-lock.c index XXXXXXX..XXXXXXX 100644 --- a/block/graph-lock.c +++ b/block/graph-lock.c @@ -XXX,XX +XXX,XX @@ #include "block/block.h" #include "block/block_int.h" +/* Dummy lock object to use for Thread Safety Analysis (TSA) */ +BdrvGraphLock graph_lock; + /* Protects the list of aiocontext and orphaned_reader_count */ static QemuMutex aio_context_list_lock; -- 2.38.1 Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-16-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block_int-common.h | 4 ++-- include/block/graph-lock.h | 4 ++-- block.c | 4 ++-- 3 files changed, 6 insertions(+), 6 deletions(-) diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -XXX,XX +XXX,XX @@ struct BdrvChildClass { void (*activate)(BdrvChild *child, Error **errp); int (*inactivate)(BdrvChild *child); - void (*attach)(BdrvChild *child); - void (*detach)(BdrvChild *child); + void GRAPH_WRLOCK_PTR (*attach)(BdrvChild *child); + void GRAPH_WRLOCK_PTR (*detach)(BdrvChild *child); /* * Notifies the parent that the filename of its child has changed (e.g. diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/graph-lock.h +++ b/include/block/graph-lock.h @@ -XXX,XX +XXX,XX @@ bdrv_graph_rdunlock_main_loop(void); * or there is at least a reader helding the rdlock. * In this way an incoming writer is aware of the read and waits. */ -void assert_bdrv_graph_readable(void); +void GRAPH_RDLOCK assert_bdrv_graph_readable(void); /* * assert_bdrv_graph_writable: * Make sure that the writer is the main loop and has set @has_writer, * so that incoming readers will pause. */ -void assert_bdrv_graph_writable(void); +void GRAPH_WRLOCK assert_bdrv_graph_writable(void); /* * Calling this function tells TSA that we know that the lock is effectively diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format, *child_flags = flags; } -static void bdrv_child_cb_attach(BdrvChild *child) +static void GRAPH_WRLOCK bdrv_child_cb_attach(BdrvChild *child) { BlockDriverState *bs = child->opaque; @@ -XXX,XX +XXX,XX @@ static void bdrv_child_cb_attach(BdrvChild *child) } } -static void bdrv_child_cb_detach(BdrvChild *child) +static void GRAPH_WRLOCK bdrv_child_cb_detach(BdrvChild *child) { BlockDriverState *bs = child->opaque; -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> Add co_wrapper_bdrv_rdlock and co_wrapper_mixed_bdrv_rdlock option to the block-coroutine-wrapper.py script. This "_bdrv_rdlock" option takes and releases the graph rdlock when a coroutine function is created. This means that when used together with "_mixed", the function marked with co_wrapper_mixed_bdrv_rdlock will support both coroutine and non-coroutine case, and in the latter case it will create a coroutine that takes and releases the rdlock. When called from a coroutine, the caller must already hold the graph lock. Example: void co_wrapper_mixed_bdrv_rdlock bdrv_f1(); Becomes static void bdrv_co_enter_f1() { bdrv_graph_co_rdlock(); bdrv_co_function(); bdrv_graph_co_rdunlock(); } void bdrv_f1() { if (qemu_in_coroutine) { assume_graph_lock(); bdrv_co_function(); } else { qemu_co_enter(bdrv_co_enter_f1); ... } } When used alone, the function will not work in coroutine context, and when called in non-coroutine context it will create a new coroutine that takes care of taking and releasing the rdlock automatically. Example: void co_wrapper_bdrv_rdlock bdrv_f1(); Becomes static void bdrv_co_enter_f1() { bdrv_graph_co_rdlock(); bdrv_co_function(); bdrv_graph_co_rdunlock(); } void bdrv_f1() { assert(!qemu_in_coroutine()); qemu_co_enter(bdrv_co_enter_f1); ... } About their usage: - co_wrapper does not take the rdlock, so it can be used also outside the block layer. - co_wrapper_mixed will be used by many blk_* functions, since the coroutine function needs to call blk_wait_while_drained() and the rdlock *must* be taken afterwards, otherwise it's a deadlock. In the future this annotation will go away, and blk_* will use co_wrapper directly. - co_wrapper_bdrv_rdlock will be used by BlockDriver callbacks, ideally by all of them in the future. - co_wrapper_mixed_bdrv_rdlock will be used by the remaining functions that are still called by coroutine and non-coroutine context. In the future this annotation will go away, as we will split such mixed functions. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-17-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- include/block/block-common.h | 9 ++++++++- scripts/block-coroutine-wrapper.py | 12 ++++++++++++ 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/include/block/block-common.h b/include/block/block-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-common.h +++ b/include/block/block-common.h @@ -XXX,XX +XXX,XX @@ * * Usage: read docs/devel/block-coroutine-wrapper.rst * - * There are 2 kind of specifiers: + * There are 4 kind of specifiers: * - co_wrapper functions can be called by only non-coroutine context, because * they always generate a new coroutine. * - co_wrapper_mixed functions can be called by both coroutine and * non-coroutine context. + * - co_wrapper_bdrv_rdlock are co_wrapper functions but automatically take and + * release the graph rdlock when creating a new coroutine + * - co_wrapper_mixed_bdrv_rdlock are co_wrapper_mixed functions but + * automatically take and release the graph rdlock when creating a new + * coroutine. */ #define co_wrapper #define co_wrapper_mixed +#define co_wrapper_bdrv_rdlock +#define co_wrapper_mixed_bdrv_rdlock #include "block/dirty-bitmap.h" #include "block/blockjob.h" diff --git a/scripts/block-coroutine-wrapper.py b/scripts/block-coroutine-wrapper.py index XXXXXXX..XXXXXXX 100644 --- a/scripts/block-coroutine-wrapper.py +++ b/scripts/block-coroutine-wrapper.py @@ -XXX,XX +XXX,XX @@ def __init__(self, return_type: str, name: str, args: str, self.struct_name = snake_to_camel(self.name) self.args = [ParamDecl(arg.strip()) for arg in args.split(',')] self.create_only_co = 'mixed' not in variant + self.graph_rdlock = 'bdrv_rdlock' in variant subsystem, subname = self.name.split('_', 1) self.co_name = f'{subsystem}_co_{subname}' @@ -XXX,XX +XXX,XX @@ def create_mixed_wrapper(func: FuncDecl) -> str: """ name = func.co_name struct_name = func.struct_name + graph_assume_lock = 'assume_graph_lock();' if func.graph_rdlock else '' + return f"""\ {func.return_type} {func.name}({ func.gen_list('{decl}') }) {{ if (qemu_in_coroutine()) {{ + {graph_assume_lock} return {name}({ func.gen_list('{name}') }); }} else {{ {struct_name} s = {{ @@ -XXX,XX +XXX,XX @@ def gen_wrapper(func: FuncDecl) -> str: name = func.co_name struct_name = func.struct_name + graph_lock='' + graph_unlock='' + if func.graph_rdlock: + graph_lock=' bdrv_graph_co_rdlock();' + graph_unlock=' bdrv_graph_co_rdunlock();' + creation_function = create_mixed_wrapper if func.create_only_co: creation_function = create_co_wrapper @@ -XXX,XX +XXX,XX @@ def gen_wrapper(func: FuncDecl) -> str: {{ {struct_name} *s = opaque; +{graph_lock} s->ret = {name}({ func.gen_list('s->{name}') }); +{graph_unlock} s->poll_state.in_progress = false; aio_wait_kick(); -- 2.38.1 From: Emanuele Giuseppe Esposito <eesposit@redhat.com> Take the rdlock already, before we add the assertions. All these functions either read the graph recursively, or call BlockDriver callbacks that will eventually need to be protected by the graph rdlock. Do it now to all functions together, because many of these recursively call each other. For example, bdrv_co_truncate calls BlockDriver->bdrv_co_truncate, and some driver callbacks implement their own .bdrv_co_truncate by calling bdrv_flush inside. So if bdrv_flush asserts but bdrv_truncate does not take the rdlock yet, the assertion will always fail. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-18-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/coroutines.h | 2 +- include/block/block-io.h | 53 +++++++++++++++++++++++----------------- 2 files changed, 32 insertions(+), 23 deletions(-) diff --git a/block/coroutines.h b/block/coroutines.h index XXXXXXX..XXXXXXX 100644 --- a/block/coroutines.h +++ b/block/coroutines.h @@ -XXX,XX +XXX,XX @@ nbd_co_do_establish_connection(BlockDriverState *bs, bool blocking, * the "I/O or GS" API. */ -int co_wrapper_mixed +int co_wrapper_mixed_bdrv_rdlock bdrv_common_block_status_above(BlockDriverState *bs, BlockDriverState *base, bool include_base, diff --git a/include/block/block-io.h b/include/block/block-io.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -XXX,XX +XXX,XX @@ * to catch when they are accidentally called by the wrong API. */ -int co_wrapper_mixed bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset, - int64_t bytes, - BdrvRequestFlags flags); +int co_wrapper_mixed_bdrv_rdlock +bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset, int64_t bytes, + BdrvRequestFlags flags); + int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags); -int co_wrapper_mixed bdrv_pread(BdrvChild *child, int64_t offset, - int64_t bytes, void *buf, - BdrvRequestFlags flags); -int co_wrapper_mixed bdrv_pwrite(BdrvChild *child, int64_t offset, - int64_t bytes, const void *buf, - BdrvRequestFlags flags); -int co_wrapper_mixed bdrv_pwrite_sync(BdrvChild *child, int64_t offset, - int64_t bytes, const void *buf, - BdrvRequestFlags flags); + +int co_wrapper_mixed_bdrv_rdlock +bdrv_pread(BdrvChild *child, int64_t offset, int64_t bytes, void *buf, + BdrvRequestFlags flags); + +int co_wrapper_mixed_bdrv_rdlock +bdrv_pwrite(BdrvChild *child, int64_t offset,int64_t bytes, + const void *buf, BdrvRequestFlags flags); + +int co_wrapper_mixed_bdrv_rdlock +bdrv_pwrite_sync(BdrvChild *child, int64_t offset, int64_t bytes, + const void *buf, BdrvRequestFlags flags); + int coroutine_fn bdrv_co_pwrite_sync(BdrvChild *child, int64_t offset, int64_t bytes, const void *buf, BdrvRequestFlags flags); @@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset, void bdrv_drain(BlockDriverState *bs); -int co_wrapper_mixed +int co_wrapper_mixed_bdrv_rdlock bdrv_truncate(BdrvChild *child, int64_t offset, bool exact, PreallocMode prealloc, BdrvRequestFlags flags, Error **errp); -int co_wrapper_mixed bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, - BdrvCheckMode fix); +int co_wrapper_mixed_bdrv_rdlock +bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix); /* Invalidate any cached metadata used by image formats */ -int co_wrapper_mixed bdrv_invalidate_cache(BlockDriverState *bs, - Error **errp); -int co_wrapper_mixed bdrv_flush(BlockDriverState *bs); -int co_wrapper_mixed bdrv_pdiscard(BdrvChild *child, int64_t offset, - int64_t bytes); -int co_wrapper_mixed +int co_wrapper_mixed_bdrv_rdlock +bdrv_invalidate_cache(BlockDriverState *bs, Error **errp); + +int co_wrapper_mixed_bdrv_rdlock bdrv_flush(BlockDriverState *bs); + +int co_wrapper_mixed_bdrv_rdlock +bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes); + +int co_wrapper_mixed_bdrv_rdlock bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); -int co_wrapper_mixed + +int co_wrapper_mixed_bdrv_rdlock bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); /** -- 2.38.1 The generated coroutine wrappers already take care to take the lock in the non-coroutine path, and assume that the lock is already taken in the coroutine path. The only thing we need to do for the wrapped function is adding the GRAPH_RDLOCK annotation. Doing so also allows us to mark the corresponding callbacks in BlockDriver as GRAPH_RDLOCK_PTR. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-19-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/coroutines.h | 17 ++++++++++------- include/block/block_int-common.h | 20 +++++++++----------- block.c | 2 ++ block/io.c | 2 ++ 4 files changed, 23 insertions(+), 18 deletions(-) diff --git a/block/coroutines.h b/block/coroutines.h index XXXXXXX..XXXXXXX 100644 --- a/block/coroutines.h +++ b/block/coroutines.h @@ -XXX,XX +XXX,XX @@ * the I/O API. */ -int coroutine_fn bdrv_co_check(BlockDriverState *bs, - BdrvCheckResult *res, BdrvCheckMode fix); -int coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs, Error **errp); +int coroutine_fn GRAPH_RDLOCK +bdrv_co_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix); + +int coroutine_fn GRAPH_RDLOCK +bdrv_co_invalidate_cache(BlockDriverState *bs, Error **errp); int coroutine_fn bdrv_co_common_block_status_above(BlockDriverState *bs, @@ -XXX,XX +XXX,XX @@ bdrv_co_common_block_status_above(BlockDriverState *bs, BlockDriverState **file, int *depth); -int coroutine_fn bdrv_co_readv_vmstate(BlockDriverState *bs, - QEMUIOVector *qiov, int64_t pos); -int coroutine_fn bdrv_co_writev_vmstate(BlockDriverState *bs, - QEMUIOVector *qiov, int64_t pos); +int coroutine_fn GRAPH_RDLOCK +bdrv_co_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); + +int coroutine_fn GRAPH_RDLOCK +bdrv_co_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); int coroutine_fn nbd_co_do_establish_connection(BlockDriverState *bs, bool blocking, diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index XXXXXXX..XXXXXXX 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -XXX,XX +XXX,XX @@ struct BlockDriver { /* * Invalidate any cached meta-data. */ - void coroutine_fn (*bdrv_co_invalidate_cache)(BlockDriverState *bs, - Error **errp); + void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_invalidate_cache)( + BlockDriverState *bs, Error **errp); /* * Flushes all data for all layers by calling bdrv_co_flush for underlying @@ -XXX,XX +XXX,XX @@ struct BlockDriver { Error **errp); BlockStatsSpecific *(*bdrv_get_specific_stats)(BlockDriverState *bs); - int coroutine_fn (*bdrv_save_vmstate)(BlockDriverState *bs, - QEMUIOVector *qiov, - int64_t pos); - int coroutine_fn (*bdrv_load_vmstate)(BlockDriverState *bs, - QEMUIOVector *qiov, - int64_t pos); + int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_save_vmstate)( + BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); + + int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_load_vmstate)( + BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); /* removable device specific */ bool (*bdrv_is_inserted)(BlockDriverState *bs); @@ -XXX,XX +XXX,XX @@ struct BlockDriver { * Returns 0 for completed check, -errno for internal errors. * The check results are stored in result. */ - int coroutine_fn (*bdrv_co_check)(BlockDriverState *bs, - BdrvCheckResult *result, - BdrvCheckMode fix); + int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_check)( + BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix); void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event); diff --git a/block.c b/block.c index XXXXXXX..XXXXXXX 100644 --- a/block.c +++ b/block.c @@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix) { IO_CODE(); + assert_bdrv_graph_readable(); if (bs->drv == NULL) { return -ENOMEDIUM; } @@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs, Error **errp) IO_CODE(); assert(!(bs->open_flags & BDRV_O_INACTIVE)); + assert_bdrv_graph_readable(); if (bs->drv->bdrv_co_invalidate_cache) { bs->drv->bdrv_co_invalidate_cache(bs, &local_err); diff --git a/block/io.c b/block/io.c index XXXXXXX..XXXXXXX 100644 --- a/block/io.c +++ b/block/io.c @@ -XXX,XX +XXX,XX @@ bdrv_co_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) BlockDriverState *child_bs = bdrv_primary_bs(bs); int ret; IO_CODE(); + assert_bdrv_graph_readable(); ret = bdrv_check_qiov_request(pos, qiov->size, qiov, 0, NULL); if (ret < 0) { @@ -XXX,XX +XXX,XX @@ bdrv_co_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) BlockDriverState *child_bs = bdrv_primary_bs(bs); int ret; IO_CODE(); + assert_bdrv_graph_readable(); ret = bdrv_check_qiov_request(pos, qiov->size, qiov, 0, NULL); if (ret < 0) { -- 2.38.1