This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_filter_or_cow_bs() need to hold a reader lock for the graph because
it calls bdrv_filter_or_cow_child(), which accesses bs->file/backing.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
include/block/block_int-io.h | 3 ++-
block.c | 31 ++++++++++++++++++-------------
block/stream.c | 4 ++++
blockdev.c | 2 +-
nbd/server.c | 6 ++++++
5 files changed, 31 insertions(+), 15 deletions(-)
diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h
index 26bff94e4e..6800af7590 100644
--- a/include/block/block_int-io.h
+++ b/include/block/block_int-io.h
@@ -150,7 +150,8 @@ bdrv_filter_bs(BlockDriverState *bs)
return child_bs(bdrv_filter_child(bs));
}
-static inline BlockDriverState *bdrv_filter_or_cow_bs(BlockDriverState *bs)
+static inline BlockDriverState * GRAPH_RDLOCK
+bdrv_filter_or_cow_bs(BlockDriverState *bs)
{
IO_CODE();
return child_bs(bdrv_filter_or_cow_child(bs));
diff --git a/block.c b/block.c
index 5f92eb4950..a6060eddbc 100644
--- a/block.c
+++ b/block.c
@@ -5435,17 +5435,6 @@ static int bdrv_replace_node_common(BlockDriverState *from,
GLOBAL_STATE_CODE();
- 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);
@@ -5457,6 +5446,17 @@ static int bdrv_replace_node_common(BlockDriverState *from,
bdrv_graph_wrlock(to);
+ 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))
+ {
+ ;
+ }
+ }
+
/*
* Do the replacement without permission update.
* Replacement may influence the permissions, we should calculate new
@@ -5504,10 +5504,14 @@ int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
int bdrv_drop_filter(BlockDriverState *bs, Error **errp)
{
+ BlockDriverState *child_bs;
+
GLOBAL_STATE_CODE();
+ bdrv_graph_rdlock_main_loop();
+ child_bs = bdrv_filter_or_cow_bs(bs);
+ bdrv_graph_rdunlock_main_loop();
- return bdrv_replace_node_common(bs, bdrv_filter_or_cow_bs(bs), true, true,
- errp);
+ return bdrv_replace_node_common(bs, child_bs, true, true, errp);
}
/*
@@ -6509,6 +6513,7 @@ bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
{
GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
while (top && top != base) {
top = bdrv_filter_or_cow_bs(top);
diff --git a/block/stream.c b/block/stream.c
index 51333e460b..2781441191 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -60,6 +60,8 @@ static int stream_prepare(Job *job)
Error *local_err = NULL;
int ret = 0;
+ GLOBAL_STATE_CODE();
+
/* We should drop filter at this point, as filter hold the backing chain */
bdrv_cor_filter_drop(s->cor_filter_bs);
s->cor_filter_bs = NULL;
@@ -78,8 +80,10 @@ static int stream_prepare(Job *job)
bdrv_drained_begin(unfiltered_bs_cow);
}
+ bdrv_graph_rdlock_main_loop();
base = bdrv_filter_or_cow_bs(s->above_base);
unfiltered_base = bdrv_skip_filters(base);
+ bdrv_graph_rdunlock_main_loop();
if (bdrv_cow_child(unfiltered_bs)) {
const char *base_id = NULL, *base_fmt = NULL;
diff --git a/blockdev.c b/blockdev.c
index 25c6c6e8d3..240834b6d4 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2492,8 +2492,8 @@ void qmp_block_stream(const char *job_id, const char *device,
/*
* Check for op blockers in the whole chain between bs and base (or bottom)
*/
- iter_end = bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs;
bdrv_graph_rdlock_main_loop();
+ iter_end = bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs;
for (iter = bs; iter && iter != iter_end;
iter = bdrv_filter_or_cow_bs(iter))
{
diff --git a/nbd/server.c b/nbd/server.c
index 859c163d19..895cf0a752 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1689,6 +1689,7 @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args,
size_t i;
int ret;
+ GLOBAL_STATE_CODE();
assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
if (!nbd_server_is_running()) {
@@ -1743,6 +1744,8 @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args,
}
exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
+ bdrv_graph_rdlock_main_loop();
+
for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) {
exp->nr_export_bitmaps++;
}
@@ -1825,9 +1828,12 @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args,
QTAILQ_INSERT_TAIL(&exports, exp, next);
+ bdrv_graph_rdunlock_main_loop();
+
return 0;
fail:
+ bdrv_graph_rdunlock_main_loop();
g_free(exp->export_bitmaps);
g_free(exp->name);
g_free(exp->description);
--
2.41.0