The following changes since commit 19b599f7664b2ebfd0f405fb79c14dd241557452:

Merge remote-tracking branch 'remotes/armbru/tags/pull-error-2018-08-27-v2' into staging (2018-08-27 16:44:20 +0100)

https://git.xanclic.moe/XanClic/qemu.git tags/pull-block-2018-08-31-v2

for you to fetch changes up to e21a1c9831fc80ae3f3c1affdfa43350035d8588:

jobs: remove job_defer_to_main_loop (2018-08-31 16:28:33 +0200)

- (Block) job exit refactoring, part 1

(removing job_defer_to_main_loop())

- test-bdrv-drain leak fix

John Snow (9):

jobs: change start callback to run callback

jobs: canonize Error object

jobs: add exit shim

block/commit: utilize job_exit shim

block/mirror: utilize job_exit shim

jobs: utilize job_exit shim

block/backup: make function variables consistently named

jobs: remove ret argument to job_completed; privatize it

jobs: remove job_defer_to_main_loop

Marc-André Lureau (1):

tests: fix bdrv-drain leak

include/qemu/job.h | 70 ++++++++++++++++-----------------

block/backup.c | 81 ++++++++++++++++-----------------------

block/commit.c | 29 +++++---------

block/create.c | 19 +++------

block/mirror.c | 39 ++++++++-----------

block/stream.c | 29 ++++++--------

job-qmp.c | 5 ++-

job.c | 73 ++++++++++++-----------------------

tests/test-bdrv-drain.c | 14 +++----

tests/test-blockjob-txn.c | 25 +++++-------

tests/test-blockjob.c | 17 ++++----

trace-events | 2 +-

12 files changed, 161 insertions(+), 242 deletions(-)

2.17.1

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Spotted by ASAN:

=================================================================

==5378==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 65536 byte(s) in 1 object(s) allocated from:

#0 0x7f788f83bc48 in malloc (/lib64/libasan.so.5+0xeec48)

#1 0x7f788c9923c5 in g_malloc (/lib64/libglib-2.0.so.0+0x523c5)

#2 0x5622a1fe37bc in coroutine_trampoline /home/elmarco/src/qq/util/coroutine-ucontext.c:116

#3 0x7f788a15d75f in __correctly_grouped_prefixwc (/lib64/libc.so.6+0x4c75f)

(Broken in commit 4c8158e359d.)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Message-id: 20180809114417.28718-3-marcandre.lureau@redhat.com

tests/test-bdrv-drain.c | 1 +

1 file changed, 1 insertion(+)

diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c

index XXXXXXX..XXXXXXX 100644

--- a/tests/test-bdrv-drain.c

+++ b/tests/test-bdrv-drain.c

@@ -XXX,XX +XXX,XX @@ static void coroutine_fn test_co_delete_by_drain(void *opaque)

}

dbdd->done = true;

+ g_free(buffer);

}

/**

2.17.1

From: John Snow <jsnow@redhat.com>

Presently we codify the entry point for a job as the "start" callback,

but a more apt name would be "run" to clarify the idea that when this

function returns we consider the job to have "finished," except for

any cleanup which occurs in separate callbacks later.

As part of this clarification, change the signature to include an error

object and a return code. The error ptr is not yet used, and the return

code while captured, will be overwritten by actions in the job_completed

function.

Signed-off-by: John Snow <jsnow@redhat.com>

Reviewed-by: Max Reitz <mreitz@redhat.com>

Message-id: 20180830015734.19765-2-jsnow@redhat.com

Reviewed-by: Jeff Cody <jcody@redhat.com>

include/qemu/job.h | 2 +-

block/backup.c | 7 ++++---

block/commit.c | 7 ++++---

block/create.c | 8 +++++---

block/mirror.c | 10 ++++++----

block/stream.c | 7 ++++---

job.c | 6 +++---

tests/test-bdrv-drain.c | 7 ++++---

tests/test-blockjob-txn.c | 16 ++++++++--------

tests/test-blockjob.c | 7 ++++---

10 files changed, 43 insertions(+), 34 deletions(-)

diff --git a/include/qemu/job.h b/include/qemu/job.h

index XXXXXXX..XXXXXXX 100644

--- a/include/qemu/job.h

+++ b/include/qemu/job.h

@@ -XXX,XX +XXX,XX @@ struct JobDriver {

JobType job_type;

/** Mandatory: Entrypoint for the Coroutine. */

- CoroutineEntry *start;

+ int coroutine_fn (*run)(Job *job, Error **errp);

/**

* If the callback is not NULL, it will be invoked when the job transitions

diff --git a/block/backup.c b/block/backup.c

index XXXXXXX..XXXXXXX 100644

--- a/block/backup.c

+++ b/block/backup.c

@@ -XXX,XX +XXX,XX @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)

bdrv_dirty_iter_free(dbi);

}

-static void coroutine_fn backup_run(void *opaque)

+static int coroutine_fn backup_run(Job *opaque_job, Error **errp)

{

- BackupBlockJob *job = opaque;

+ BackupBlockJob *job = container_of(opaque_job, BackupBlockJob, common.job);

BackupCompleteData *data;

BlockDriverState *bs = blk_bs(job->common.blk);

int64_t offset, nb_clusters;

@@ -XXX,XX +XXX,XX @@ static void coroutine_fn backup_run(void *opaque)

data = g_malloc(sizeof(*data));

data->ret = ret;

job_defer_to_main_loop(&job->common.job, backup_complete, data);

+ return ret;

}

static const BlockJobDriver backup_job_driver = {

@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver backup_job_driver = {

.free = block_job_free,

.user_resume = block_job_user_resume,

.drain = block_job_drain,

- .start = backup_run,

+ .run = backup_run,

.commit = backup_commit,

.abort = backup_abort,

.clean = backup_clean,

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 void commit_complete(Job *job, void *opaque)

bdrv_unref(top);

}

-static void coroutine_fn commit_run(void *opaque)

+static int coroutine_fn commit_run(Job *job, Error **errp)

{

- CommitBlockJob *s = opaque;

+ CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);

CommitCompleteData *data;

int64_t offset;

uint64_t delay_ns = 0;

@@ -XXX,XX +XXX,XX @@ out:

data = g_malloc(sizeof(*data));

data->ret = ret;

job_defer_to_main_loop(&s->common.job, commit_complete, data);

+ return ret;

}

static const BlockJobDriver commit_job_driver = {

@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_job_driver = {

.free = block_job_free,

.user_resume = block_job_user_resume,

.drain = block_job_drain,

- .start = commit_run,

+ .run = commit_run,

},

};

diff --git a/block/create.c b/block/create.c

index XXXXXXX..XXXXXXX 100644

--- a/block/create.c

+++ b/block/create.c

@@ -XXX,XX +XXX,XX @@ static void blockdev_create_complete(Job *job, void *opaque)

job_completed(job, s->ret, s->err);

}

-static void coroutine_fn blockdev_create_run(void *opaque)

+static int coroutine_fn blockdev_create_run(Job *job, Error **errp)

{

- BlockdevCreateJob *s = opaque;

+ BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);

job_progress_set_remaining(&s->common, 1);

s->ret = s->drv->bdrv_co_create(s->opts, &s->err);

@@ -XXX,XX +XXX,XX @@ static void coroutine_fn blockdev_create_run(void *opaque)

qapi_free_BlockdevCreateOptions(s->opts);

job_defer_to_main_loop(&s->common, blockdev_create_complete, NULL);

+ return s->ret;

}

static const JobDriver blockdev_create_job_driver = {

.instance_size = sizeof(BlockdevCreateJob),

.job_type = JOB_TYPE_CREATE,

- .start = blockdev_create_run,

+ .run = blockdev_create_run,

};

void qmp_blockdev_create(const char *job_id, BlockdevCreateOptions *options,

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 int mirror_flush(MirrorBlockJob *s)

return ret;

}

-static void coroutine_fn mirror_run(void *opaque)

+static int coroutine_fn mirror_run(Job *job, Error **errp)

{

- MirrorBlockJob *s = opaque;

+ MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);

MirrorExitData *data;

BlockDriverState *bs = s->mirror_top_bs->backing->bs;

BlockDriverState *target_bs = blk_bs(s->target);

@@ -XXX,XX +XXX,XX @@ immediate_exit:

if (need_drain) {

bdrv_drained_begin(bs);

}

+

job_defer_to_main_loop(&s->common.job, mirror_exit, data);

+ return ret;

}

static void mirror_complete(Job *job, Error **errp)

@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver mirror_job_driver = {

.free = block_job_free,

.user_resume = block_job_user_resume,

.drain = block_job_drain,

- .start = mirror_run,

+ .run = mirror_run,

.pause = mirror_pause,

.complete = mirror_complete,

},

@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_active_job_driver = {

.free = block_job_free,

.user_resume = block_job_user_resume,

.drain = block_job_drain,

- .start = mirror_run,

+ .run = mirror_run,

.pause = mirror_pause,

.complete = mirror_complete,

},

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 @@ out:

g_free(data);

}

-static void coroutine_fn stream_run(void *opaque)

+static int coroutine_fn stream_run(Job *job, Error **errp)

{

- StreamBlockJob *s = opaque;

+ StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);

StreamCompleteData *data;

BlockBackend *blk = s->common.blk;

BlockDriverState *bs = blk_bs(blk);

@@ -XXX,XX +XXX,XX @@ out:

data = g_malloc(sizeof(*data));

data->ret = ret;

job_defer_to_main_loop(&s->common.job, stream_complete, data);

+ return ret;

}

static const BlockJobDriver stream_job_driver = {

@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver stream_job_driver = {

.instance_size = sizeof(StreamBlockJob),

.job_type = JOB_TYPE_STREAM,

.free = block_job_free,

- .start = stream_run,

+ .run = stream_run,

.user_resume = block_job_user_resume,

.drain = block_job_drain,

},

diff --git a/job.c b/job.c

index XXXXXXX..XXXXXXX 100644

--- a/job.c

+++ b/job.c

@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)

{

Job *job = opaque;

- assert(job && job->driver && job->driver->start);

+ assert(job && job->driver && job->driver->run);

job_pause_point(job);

- job->driver->start(job);

+ job->ret = job->driver->run(job, NULL);

}

void job_start(Job *job)

{

assert(job && !job_started(job) && job->paused &&

- job->driver && job->driver->start);

+ job->driver && job->driver->run);

job->co = qemu_coroutine_create(job_co_entry, job);

job->pause_count--;

job->busy = true;

diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c

index XXXXXXX..XXXXXXX 100644

--- a/tests/test-bdrv-drain.c

+++ b/tests/test-bdrv-drain.c

@@ -XXX,XX +XXX,XX @@ static void test_job_completed(Job *job, void *opaque)

job_completed(job, 0, NULL);

}

-static void coroutine_fn test_job_start(void *opaque)

+static int coroutine_fn test_job_run(Job *job, Error **errp)

{

- TestBlockJob *s = opaque;

+ TestBlockJob *s = container_of(job, TestBlockJob, common.job);

job_transition_to_ready(&s->common.job);

while (!s->should_complete) {

@@ -XXX,XX +XXX,XX @@ static void coroutine_fn test_job_start(void *opaque)

}

job_defer_to_main_loop(&s->common.job, test_job_completed, NULL);

+ return 0;

}

static void test_job_complete(Job *job, Error **errp)

@@ -XXX,XX +XXX,XX @@ BlockJobDriver test_job_driver = {

.free = block_job_free,

.user_resume = block_job_user_resume,

.drain = block_job_drain,

- .start = test_job_start,

+ .run = test_job_run,

.complete = test_job_complete,

},

};

diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c

index XXXXXXX..XXXXXXX 100644

--- a/tests/test-blockjob-txn.c

+++ b/tests/test-blockjob-txn.c

@@ -XXX,XX +XXX,XX @@ static void test_block_job_complete(Job *job, void *opaque)

bdrv_unref(bs);

}

-static void coroutine_fn test_block_job_run(void *opaque)

+static int coroutine_fn test_block_job_run(Job *job, Error **errp)

{

- TestBlockJob *s = opaque;

- BlockJob *job = &s->common;

+ TestBlockJob *s = container_of(job, TestBlockJob, common.job);

while (s->iterations--) {

if (s->use_timer) {

- job_sleep_ns(&job->job, 0);

+ job_sleep_ns(job, 0);

} else {

- job_yield(&job->job);

+ job_yield(job);

}

- if (job_is_cancelled(&job->job)) {

+ if (job_is_cancelled(job)) {

break;

}

}

- job_defer_to_main_loop(&job->job, test_block_job_complete,

+ job_defer_to_main_loop(job, test_block_job_complete,

(void *)(intptr_t)s->rc);

+ return s->rc;

}

typedef struct {

@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver test_block_job_driver = {

.free = block_job_free,

.user_resume = block_job_user_resume,

.drain = block_job_drain,

- .start = test_block_job_run,

+ .run = test_block_job_run,

},

};

diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c

index XXXXXXX..XXXXXXX 100644

--- a/tests/test-blockjob.c

+++ b/tests/test-blockjob.c

@@ -XXX,XX +XXX,XX @@ static void cancel_job_complete(Job *job, Error **errp)

s->should_complete = true;

}

-static void coroutine_fn cancel_job_start(void *opaque)

+static int coroutine_fn cancel_job_run(Job *job, Error **errp)

{

- CancelJob *s = opaque;

+ CancelJob *s = container_of(job, CancelJob, common.job);

while (!s->should_complete) {

if (job_is_cancelled(&s->common.job)) {

@@ -XXX,XX +XXX,XX @@ static void coroutine_fn cancel_job_start(void *opaque)

defer:

job_defer_to_main_loop(&s->common.job, cancel_job_completed, s);

+ return 0;

}

static const BlockJobDriver test_cancel_driver = {

@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver test_cancel_driver = {

.free = block_job_free,

.user_resume = block_job_user_resume,

.drain = block_job_drain,

- .start = cancel_job_start,

+ .run = cancel_job_run,

.complete = cancel_job_complete,

},

};

2.17.1

From: John Snow <jsnow@redhat.com>

Jobs presently use both an Error object in the case of the create job,

and char strings in the case of generic errors elsewhere.

Unify the two paths as just j->err, and remove the extra argument from

job_completed. The integer error code for job_completed is kept for now,

to be removed shortly in a separate patch.

Signed-off-by: John Snow <jsnow@redhat.com>

Message-id: 20180830015734.19765-3-jsnow@redhat.com

[mreitz: Dropped a superfluous g_strdup()]

Reviewed-by: Eric Blake <eblake@redhat.com>

include/qemu/job.h | 14 ++++++++------

block/backup.c | 2 +-

block/commit.c | 2 +-

block/create.c | 5 ++---

block/mirror.c | 2 +-

block/stream.c | 2 +-

job-qmp.c | 5 +++--

job.c | 18 ++++++------------

tests/test-bdrv-drain.c | 2 +-

tests/test-blockjob-txn.c | 2 +-

tests/test-blockjob.c | 2 +-

11 files changed, 26 insertions(+), 30 deletions(-)

diff --git a/include/qemu/job.h b/include/qemu/job.h

index XXXXXXX..XXXXXXX 100644

--- a/include/qemu/job.h

+++ b/include/qemu/job.h

@@ -XXX,XX +XXX,XX @@ typedef struct Job {

/** Estimated progress_current value at the completion of the job */

int64_t progress_total;

- /** Error string for a failed job (NULL if, and only if, job->ret == 0) */

- char *error;

-

/** ret code passed to job_completed. */

int ret;

+ /**

+ * Error object for a failed job.

+ * If job->ret is nonzero and an error object was not set, it will be set

+ * to strerror(-job->ret) during job_completed.

+ */

+ Error *err;

+

/** The completion function that will be called when the job completes. */

BlockCompletionFunc *cb;

@@ -XXX,XX +XXX,XX @@ void job_transition_to_ready(Job *job);

/**

* @job: The job being completed.

* @ret: The status code.

- * @error: The error message for a failing job (only with @ret < 0). If @ret is

- * negative, but NULL is given for @error, strerror() is used.

*

* Marks @job as completed. If @ret is non-zero, the job transaction it is part

* of is aborted. If @ret is zero, the job moves into the WAITING state. If it

* is the last job to complete in its transaction, all jobs in the transaction

* move from WAITING to PENDING.

*/

-void job_completed(Job *job, int ret, Error *error);

+void job_completed(Job *job, int ret);

/** Asynchronously complete the specified @job. */

void job_complete(Job *job, Error **errp);

diff --git a/block/backup.c b/block/backup.c

index XXXXXXX..XXXXXXX 100644

--- a/block/backup.c

+++ b/block/backup.c

@@ -XXX,XX +XXX,XX @@ static void backup_complete(Job *job, void *opaque)

{

BackupCompleteData *data = opaque;

- job_completed(job, data->ret, NULL);

+ job_completed(job, data->ret);

g_free(data);

}

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 void commit_complete(Job *job, void *opaque)

* bdrv_set_backing_hd() to fail. */

block_job_remove_all_bdrv(bjob);

- job_completed(job, ret, NULL);

+ job_completed(job, ret);

g_free(data);

/* If bdrv_drop_intermediate() didn't already do that, remove the commit

diff --git a/block/create.c b/block/create.c

index XXXXXXX..XXXXXXX 100644

--- a/block/create.c

+++ b/block/create.c

@@ -XXX,XX +XXX,XX @@ typedef struct BlockdevCreateJob {

BlockDriver *drv;

BlockdevCreateOptions *opts;

int ret;

- Error *err;

} BlockdevCreateJob;

static void blockdev_create_complete(Job *job, void *opaque)

{

BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);

- job_completed(job, s->ret, s->err);

+ job_completed(job, s->ret);

}

static int coroutine_fn blockdev_create_run(Job *job, Error **errp)

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn blockdev_create_run(Job *job, Error **errp)

BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);

job_progress_set_remaining(&s->common, 1);

- s->ret = s->drv->bdrv_co_create(s->opts, &s->err);

+ s->ret = s->drv->bdrv_co_create(s->opts, errp);

job_progress_update(&s->common, 1);

qapi_free_BlockdevCreateOptions(s->opts);

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 void mirror_exit(Job *job, void *opaque)

blk_insert_bs(bjob->blk, mirror_top_bs, &error_abort);

bs_opaque->job = NULL;

- job_completed(job, data->ret, NULL);

+ job_completed(job, data->ret);

g_free(data);

bdrv_drained_end(src);

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 @@ out:

}

g_free(s->backing_file_str);

- job_completed(job, data->ret, NULL);

+ job_completed(job, data->ret);

g_free(data);

}

diff --git a/job-qmp.c b/job-qmp.c

index XXXXXXX..XXXXXXX 100644

--- a/job-qmp.c

+++ b/job-qmp.c

@@ -XXX,XX +XXX,XX @@ static JobInfo *job_query_single(Job *job, Error **errp)

.status = job->status,

.current_progress = job->progress_current,

.total_progress = job->progress_total,

- .has_error = !!job->error,

- .error = g_strdup(job->error),

+ .has_error = !!job->err,

+ .error = job->err ? \

+ g_strdup(error_get_pretty(job->err)) : NULL,

};

return info;

diff --git a/job.c b/job.c

index XXXXXXX..XXXXXXX 100644

--- a/job.c

+++ b/job.c

@@ -XXX,XX +XXX,XX @@ void job_unref(Job *job)

QLIST_REMOVE(job, job_list);

- g_free(job->error);

+ error_free(job->err);

g_free(job->id);

g_free(job);

}

@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)

assert(job && job->driver && job->driver->run);

job_pause_point(job);

- job->ret = job->driver->run(job, NULL);

+ job->ret = job->driver->run(job, &job->err);

}

@@ -XXX,XX +XXX,XX @@ static void job_update_rc(Job *job)

job->ret = -ECANCELED;

}

if (job->ret) {

- if (!job->error) {

- job->error = g_strdup(strerror(-job->ret));

+ if (!job->err) {

+ error_setg(&job->err, "%s", strerror(-job->ret));

}

job_state_transition(job, JOB_STATUS_ABORTING);

}

@@ -XXX,XX +XXX,XX @@ static void job_completed_txn_success(Job *job)

}

}

-void job_completed(Job *job, int ret, Error *error)

+void job_completed(Job *job, int ret)

{

assert(job && job->txn && !job_is_completed(job));

job->ret = ret;

- if (error) {

- assert(job->ret < 0);

- job->error = g_strdup(error_get_pretty(error));

- error_free(error);

- }

-

job_update_rc(job);

trace_job_completed(job, ret, job->ret);

if (job->ret) {

@@ -XXX,XX +XXX,XX @@ void job_cancel(Job *job, bool force)

}

job_cancel_async(job, force);

if (!job_started(job)) {

- job_completed(job, -ECANCELED, NULL);

+ job_completed(job, -ECANCELED);

} else if (job->deferred_to_main_loop) {

job_completed_txn_abort(job);

} else {

diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c

index XXXXXXX..XXXXXXX 100644

--- a/tests/test-bdrv-drain.c

+++ b/tests/test-bdrv-drain.c

@@ -XXX,XX +XXX,XX @@ typedef struct TestBlockJob {

static void test_job_completed(Job *job, void *opaque)

{

- job_completed(job, 0, NULL);

+ job_completed(job, 0);

}

static int coroutine_fn test_job_run(Job *job, Error **errp)

diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c

index XXXXXXX..XXXXXXX 100644

--- a/tests/test-blockjob-txn.c

+++ b/tests/test-blockjob-txn.c

@@ -XXX,XX +XXX,XX @@ static void test_block_job_complete(Job *job, void *opaque)

rc = -ECANCELED;

}

- job_completed(job, rc, NULL);

+ job_completed(job, rc);

bdrv_unref(bs);

}

diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c

index XXXXXXX..XXXXXXX 100644

--- a/tests/test-blockjob.c

+++ b/tests/test-blockjob.c

@@ -XXX,XX +XXX,XX @@ static void cancel_job_completed(Job *job, void *opaque)

{

CancelJob *s = opaque;

s->completed = true;

- job_completed(job, 0, NULL);

+ job_completed(job, 0);

}

static void cancel_job_complete(Job *job, Error **errp)

2.17.1

From: John Snow <jsnow@redhat.com>

All jobs do the same thing when they leave their running loop:

- Store the return code in a structure

- wait to receive this structure in the main thread

- signal job completion via job_completed

Few jobs do anything beyond exactly this. Consolidate this exit

logic for a net reduction in SLOC.

More seriously, when we utilize job_defer_to_main_loop_bh to call

a function that calls job_completed, job_finalize_single will run

in a context where it has recursively taken the aio_context lock,

which can cause hangs if it puts down a reference that causes a flush.

You can observe this in practice by looking at mirror_exit's careful

placement of job_completed and bdrv_unref calls.

If we centralize job exiting, we can signal job completion from outside

of the aio_context, which should allow for job cleanup code to run with

only one lock, which makes cleanup callbacks less tricky to write.

Signed-off-by: John Snow <jsnow@redhat.com>

Reviewed-by: Max Reitz <mreitz@redhat.com>

Message-id: 20180830015734.19765-4-jsnow@redhat.com

Reviewed-by: Jeff Cody <jcody@redhat.com>

include/qemu/job.h | 11 +++++++++++

job.c | 18 ++++++++++++++++++

2 files changed, 29 insertions(+)

diff --git a/include/qemu/job.h b/include/qemu/job.h

index XXXXXXX..XXXXXXX 100644

--- a/include/qemu/job.h

+++ b/include/qemu/job.h

@@ -XXX,XX +XXX,XX @@ struct JobDriver {

*/

void (*drain)(Job *job);

+ /**

+ * If the callback is not NULL, exit will be invoked from the main thread

+ * when the job's coroutine has finished, but before transactional

+ * convergence; before @prepare or @abort.

+ *

+ * FIXME TODO: This callback is only temporary to transition remaining jobs

+ * to prepare/commit/abort/clean callbacks and will be removed before 3.1.

+ * is released.

+ */

+ void (*exit)(Job *job);

+

/**

* If the callback is not NULL, prepare will be invoked when all the jobs

* belonging to the same transaction complete; or upon this job's completion

diff --git a/job.c b/job.c

index XXXXXXX..XXXXXXX 100644

--- a/job.c

+++ b/job.c

@@ -XXX,XX +XXX,XX @@ void job_drain(Job *job)

}

+static void job_exit(void *opaque)

+{

+ Job *job = (Job *)opaque;

+ AioContext *aio_context = job->aio_context;

+

+ if (job->driver->exit) {

+ aio_context_acquire(aio_context);

+ job->driver->exit(job);

+ aio_context_release(aio_context);

+ }

+ job_completed(job, job->ret);

+}

/**

* All jobs must allow a pause point before entering their job proper. This

@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)

assert(job && job->driver && job->driver->run);

job_pause_point(job);

job->ret = job->driver->run(job, &job->err);

+ if (!job->deferred_to_main_loop) {

+ job->deferred_to_main_loop = true;

+ aio_bh_schedule_oneshot(qemu_get_aio_context(),

+ job_exit,

+ job);

+ }

2.17.1

From: John Snow <jsnow@redhat.com>

Change the manual deferment to commit_complete into the implicit

callback to job_exit, renaming commit_complete to commit_exit.

This conversion does change the timing of when job_completed is

called to after the bdrv_replace_node and bdrv_unref calls, which

could have implications for bjob->blk which will now be put down

after this cleanup.

Kevin highlights that we did not take any permissions for that backend

at job creation time, so it is safe to reorder these operations.

Signed-off-by: John Snow <jsnow@redhat.com>

Reviewed-by: Max Reitz <mreitz@redhat.com>

Message-id: 20180830015734.19765-5-jsnow@redhat.com

Reviewed-by: Jeff Cody <jcody@redhat.com>

block/commit.c | 22 +++++-----------------

1 file changed, 5 insertions(+), 17 deletions(-)

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_populate(BlockBackend *bs, BlockBackend *base,

return 0;

}

-typedef struct {

- int ret;

-} CommitCompleteData;

-

-static void commit_complete(Job *job, void *opaque)

+static void commit_exit(Job *job)

{

CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);

BlockJob *bjob = &s->common;

- CommitCompleteData *data = opaque;

BlockDriverState *top = blk_bs(s->top);

BlockDriverState *base = blk_bs(s->base);

BlockDriverState *commit_top_bs = s->commit_top_bs;

- int ret = data->ret;

bool remove_commit_top_bs = false;

/* Make sure commit_top_bs and top stay around until bdrv_replace_node() */

@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)

* the normal backing chain can be restored. */

blk_unref(s->base);

- if (!job_is_cancelled(job) && ret == 0) {

+ if (!job_is_cancelled(job) && job->ret == 0) {

/* success */

- ret = bdrv_drop_intermediate(s->commit_top_bs, base,

- s->backing_file_str);

+ job->ret = bdrv_drop_intermediate(s->commit_top_bs, base,

+ s->backing_file_str);

} else {

/* XXX Can (or should) we somehow keep 'consistent read' blocked even

* after the failed/cancelled commit job is gone? If we already wrote

@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)

* bdrv_set_backing_hd() to fail. */

block_job_remove_all_bdrv(bjob);

- job_completed(job, ret);

- g_free(data);

-

/* If bdrv_drop_intermediate() didn't already do that, remove the commit

* filter driver from the backing chain. Do this as the final step so that

* the 'consistent read' permission can be granted. */

@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)

static int coroutine_fn commit_run(Job *job, Error **errp)

{

CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);

- CommitCompleteData *data;

int64_t offset;

uint64_t delay_ns = 0;

int ret = 0;

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn commit_run(Job *job, Error **errp)

out:

qemu_vfree(buf);

- data = g_malloc(sizeof(*data));

- data->ret = ret;

- job_defer_to_main_loop(&s->common.job, commit_complete, data);

return ret;

}

@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_job_driver = {

.user_resume = block_job_user_resume,

.drain = block_job_drain,

.run = commit_run,

+ .exit = commit_exit,

},

};

2.17.1

From: John Snow <jsnow@redhat.com>

Change the manual deferment to mirror_exit into the implicit

callback to job_exit and the mirror_exit callback.

This does change the order of some bdrv_unref calls and job_completed,

but thanks to the new context in which we call .exit, this is safe to

defer the possible flushing of any nodes to the job_finalize_single

cleanup stage.

Signed-off-by: John Snow <jsnow@redhat.com>

Message-id: 20180830015734.19765-6-jsnow@redhat.com

Reviewed-by: Max Reitz <mreitz@redhat.com>

Reviewed-by: Jeff Cody <jcody@redhat.com>

block/mirror.c | 29 +++++++++++------------------

1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c

--- a/block/mirror.c

+++ b/block/mirror.c

@@ -XXX,XX +XXX,XX @@ static void mirror_wait_for_all_io(MirrorBlockJob *s)

}

-typedef struct {

- int ret;

-} MirrorExitData;

-

-static void mirror_exit(Job *job, void *opaque)

+static void mirror_exit(Job *job)

MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);

BlockJob *bjob = &s->common;

- MirrorExitData *data = opaque;

MirrorBDSOpaque *bs_opaque = s->mirror_top_bs->opaque;

AioContext *replace_aio_context = NULL;

BlockDriverState *src = s->mirror_top_bs->backing->bs;

BlockDriverState *target_bs = blk_bs(s->target);

BlockDriverState *mirror_top_bs = s->mirror_top_bs;

Error *local_err = NULL;

+ int ret = job->ret;

bdrv_release_dirty_bitmap(src, s->dirty_bitmap);

- /* Make sure that the source BDS doesn't go away before we called

- * job_completed(). */

+ /* Make sure that the source BDS doesn't go away during bdrv_replace_node,

+ * before we can call bdrv_drained_end */

bdrv_ref(src);

bdrv_ref(mirror_top_bs);

bdrv_ref(target_bs);

@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)

bdrv_set_backing_hd(target_bs, backing, &local_err);

if (local_err) {

error_report_err(local_err);

- data->ret = -EPERM;

+ ret = -EPERM;

}

}

@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)

aio_context_acquire(replace_aio_context);

}

- if (s->should_complete && data->ret == 0) {

+ if (s->should_complete && ret == 0) {

BlockDriverState *to_replace = src;

if (s->to_replace) {

to_replace = s->to_replace;

@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)

bdrv_drained_end(target_bs);

error_report_err(local_err);

- data->ret = -EPERM;

+ ret = -EPERM;

if (s->to_replace) {

@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)

blk_insert_bs(bjob->blk, mirror_top_bs, &error_abort);

bs_opaque->job = NULL;

- job_completed(job, data->ret);

- g_free(data);

bdrv_drained_end(src);

bdrv_unref(mirror_top_bs);

bdrv_unref(src);

+ job->ret = ret;

}

static void mirror_throttle(MirrorBlockJob *s)