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From: Max Reitz <mreitz@redhat.com>
To: Stefan Reiter <s.reiter@proxmox.com>,
	qemu-devel@nongnu.org, qemu-block@nongnu.org
Cc: kwolf@redhat.com, vsementsov@virtuozzo.com, slp@redhat.com,
	stefanha@redhat.com, jsnow@redhat.com, dietmar@proxmox.com
Subject: Re: [PATCH v4 3/3] backup: don't acquire aio_context in backup_clean
Date: Thu, 2 Apr 2020 14:59:15 +0200	[thread overview]
Message-ID: <d342623b-c799-6103-18c8-656b036c60de@redhat.com> (raw)
In-Reply-To: <20200401081504.200017-4-s.reiter@proxmox.com>


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On 01.04.20 10:15, Stefan Reiter wrote:
> 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 <s.reiter@proxmox.com>
> ---
> 
> With the two previous patches applied, the commit message should now hold true.
> 
>  block/backup.c | 4 ----
>  1 file changed, 4 deletions(-)

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


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  reply	other threads:[~2020-04-02 13:00 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-01  8:15 [PATCH v4 0/3] Fix some AIO context locking in jobs Stefan Reiter
2020-04-01  8:15 ` [PATCH v4 1/3] job: take each job's lock individually in job_txn_apply Stefan Reiter
2020-04-02 12:33   ` Max Reitz
2020-04-02 15:04     ` Stefan Reiter
2020-04-01  8:15 ` [PATCH v4 2/3] replication: acquire aio context before calling job_cancel_sync Stefan Reiter
2020-04-02 12:41   ` Max Reitz
2020-04-02 15:05     ` Stefan Reiter
2020-04-01  8:15 ` [PATCH v4 3/3] backup: don't acquire aio_context in backup_clean Stefan Reiter
2020-04-02 12:59   ` Max Reitz [this message]
2020-04-02 12:48 ` [PATCH v4 0/3] Fix some AIO context locking in jobs Kevin Wolf
2020-04-06 20:11   ` John Snow

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