From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59393) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1evmdD-0001QA-D0 for qemu-devel@nongnu.org; Tue, 13 Mar 2018 12:18:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1evmd9-0004bV-1n for qemu-devel@nongnu.org; Tue, 13 Mar 2018 12:18:31 -0400 From: Kevin Wolf Date: Tue, 13 Mar 2018 17:17:34 +0100 Message-Id: <20180313161803.1814-13-kwolf@redhat.com> In-Reply-To: <20180313161803.1814-1-kwolf@redhat.com> References: <20180313161803.1814-1-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 12/41] blockjobs: ensure abort is called for cancelled jobs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org From: John Snow Presently, even if a job is canceled post-completion as a result of a failing peer in a transaction, it will still call .commit because nothing has updated or changed its return code. The reason why this does not cause problems currently is because backup's implementation of .commit checks for cancellation itself. I'd like to simplify this contract: (1) Abort is called if the job/transaction fails (2) Commit is called if the job/transaction succeeds To this end: A job's return code, if 0, will be forcibly set as -ECANCELED if that job has already concluded. Remove the now redundant check in the backup job implementation. We need to check for cancellation in both block_job_completed AND block_job_completed_single, because jobs may be cancelled between those two calls; for instance in transactions. This also necessitates an ABORTING -> ABORTING transition to be allowed. The check in block_job_completed could be removed, but there's no point in starting to attempt to succeed a transaction that we know in advance will fail. This does NOT affect mirror jobs that are "canceled" during their synchronous phase. The mirror job itself forcibly sets the canceled property to false prior to ceding control, so such cases will invoke the "commit" callback. Signed-off-by: John Snow Reviewed-by: Eric Blake Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block/backup.c | 2 +- blockjob.c | 21 ++++++++++++++++----- block/trace-events | 1 + 3 files changed, 18 insertions(+), 6 deletions(-) diff --git a/block/backup.c b/block/backup.c index 7e254dabff..453cd62c24 100644 --- a/block/backup.c +++ b/block/backup.c @@ -206,7 +206,7 @@ static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret) BdrvDirtyBitmap *bm; BlockDriverState *bs = blk_bs(job->common.blk); - if (ret < 0 || block_job_is_cancelled(&job->common)) { + if (ret < 0) { /* Merge the successor back into the parent, delete nothing. */ bm = bdrv_reclaim_dirty_bitmap(bs, job->sync_bitmap, NULL); assert(bm); diff --git a/blockjob.c b/blockjob.c index 59ac4a13c7..61af628376 100644 --- a/blockjob.c +++ b/blockjob.c @@ -51,7 +51,7 @@ bool BlockJobSTT[BLOCK_JOB_STATUS__MAX][BLOCK_JOB_STATUS__MAX] = { /* P: */ [BLOCK_JOB_STATUS_PAUSED] = {0, 0, 1, 0, 0, 0, 0, 0, 0}, /* Y: */ [BLOCK_JOB_STATUS_READY] = {0, 0, 0, 0, 0, 1, 1, 1, 0}, /* S: */ [BLOCK_JOB_STATUS_STANDBY] = {0, 0, 0, 0, 1, 0, 0, 0, 0}, - /* X: */ [BLOCK_JOB_STATUS_ABORTING] = {0, 0, 0, 0, 0, 0, 0, 1, 0}, + /* X: */ [BLOCK_JOB_STATUS_ABORTING] = {0, 0, 0, 0, 0, 0, 1, 1, 0}, /* E: */ [BLOCK_JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0, 1}, /* N: */ [BLOCK_JOB_STATUS_NULL] = {0, 0, 0, 0, 0, 0, 0, 0, 0}, }; @@ -405,13 +405,22 @@ static void block_job_conclude(BlockJob *job) } } +static void block_job_update_rc(BlockJob *job) +{ + if (!job->ret && block_job_is_cancelled(job)) { + job->ret = -ECANCELED; + } + if (job->ret) { + block_job_state_transition(job, BLOCK_JOB_STATUS_ABORTING); + } +} + static void block_job_completed_single(BlockJob *job) { assert(job->completed); - if (job->ret || block_job_is_cancelled(job)) { - block_job_state_transition(job, BLOCK_JOB_STATUS_ABORTING); - } + /* Ensure abort is called for late-transactional failures */ + block_job_update_rc(job); if (!job->ret) { if (job->driver->commit) { @@ -896,7 +905,9 @@ void block_job_completed(BlockJob *job, int ret) assert(blk_bs(job->blk)->job == job); job->completed = true; job->ret = ret; - if (ret < 0 || block_job_is_cancelled(job)) { + block_job_update_rc(job); + trace_block_job_completed(job, ret, job->ret); + if (job->ret) { block_job_completed_txn_abort(job); } else { block_job_completed_txn_success(job); diff --git a/block/trace-events b/block/trace-events index 266afd9e99..5e531e0310 100644 --- a/block/trace-events +++ b/block/trace-events @@ -5,6 +5,7 @@ bdrv_open_common(void *bs, const char *filename, int flags, const char *format_n bdrv_lock_medium(void *bs, bool locked) "bs %p locked %d" # blockjob.c +block_job_completed(void *job, int ret, int jret) "job %p ret %d corrected ret %d" block_job_state_transition(void *job, int ret, const char *legal, const char *s0, const char *s1) "job %p (ret: %d) attempting %s transition (%s-->%s)" block_job_apply_verb(void *job, const char *state, const char *verb, const char *legal) "job %p in state %s; applying verb %s (%s)" -- 2.13.6