backup: don't acquire aio_context in backup_clean

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 0abf258171.

Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200407115651.69472-4-s.reiter@proxmox.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Reiter 2020-04-07 13:56:51 +02:00 committed by Kevin Wolf
parent 08558e3325
commit eca0f3524a

View File

@ -126,11 +126,7 @@ 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)