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Blame SOURCES/kvm-backup-don-t-acquire-aio_context-in-backup_clean.patch

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