From 619b3aac9790a7ca7c01846144395a318a9ab250 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Wed, 8 Apr 2020 17:29:14 +0100 Subject: [PATCH 3/6] backup: don't acquire aio_context in backup_clean RH-Author: Kevin Wolf Message-id: <20200408172917.18712-4-kwolf@redhat.com> Patchwork-id: 94596 O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH 3/6] backup: don't acquire aio_context in backup_clean Bugzilla: 1817621 RH-Acked-by: Eric Blake RH-Acked-by: Danilo de Paula RH-Acked-by: Max Reitz From: Stefan Reiter All code-paths leading to backup_clean (via job_clean) have the job's context already acquired. The job's context is guaranteed to be the same as the one used by backup_top via backup_job_create. Since the previous logic effectively acquired the lock twice, this broke cleanup of backups for disks using IO threads, since the BDRV_POLL_WHILE in bdrv_backup_top_drop -> bdrv_do_drained_begin would only release the lock once, thus deadlocking with the IO thread. This is a partial revert of 0abf2581717a19. Signed-off-by: Stefan Reiter Reviewed-by: Max Reitz Message-Id: <20200407115651.69472-4-s.reiter@proxmox.com> Signed-off-by: Kevin Wolf (cherry picked from commit eca0f3524a4eb57d03a56b0cbcef5527a0981ce4) Signed-off-by: Kevin Wolf Signed-off-by: Danilo C. L. de Paula --- block/backup.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/block/backup.c b/block/backup.c index 1383e21..ec50946 100644 --- a/block/backup.c +++ b/block/backup.c @@ -135,11 +135,7 @@ static void backup_abort(Job *job) static void backup_clean(Job *job) { BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); - AioContext *aio_context = bdrv_get_aio_context(s->backup_top); - - aio_context_acquire(aio_context); bdrv_backup_top_drop(s->backup_top); - aio_context_release(aio_context); } void backup_do_checkpoint(BlockJob *job, Error **errp) -- 1.8.3.1