From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: Alberto Garcia <berto@igalia.com>,
qemu-devel@nongnu.org, qemu-block@nongnu.org,
Max Reitz <mreitz@redhat.com>
Subject: Re: [PATCH v4 4/6] block: Support multiple reopening with x-blockdev-reopen
Date: Thu, 6 May 2021 12:21:42 +0300 [thread overview]
Message-ID: <fee69f02-6553-ff02-0bae-ee4e3cee343a@virtuozzo.com> (raw)
In-Reply-To: <YJLFboRME/eFXetd@merkur.fritz.box>
05.05.2021 19:18, Kevin Wolf wrote:
>> And then, bdrv_reopen_multiple() is called with no aio context
>> acquired, and no drained section.. And it shoud be refactored to
>> properly operate with acquiring and realeasing the contexts and
>> drained sections when needed...
> The drained section shouldn't be a problem, we can keep this. In fact,
> we need this, it is a documented requirement of bdrv_reopen_multiple().
> We just need to drop the AioContext lock after drained_begin.
>
> bdrv_reopen_multiple() should really document its requirements regarding
> AioContext locks. It probably doesn't really care, but requires that
> it be called from the main thread.
>
>> (note preexisting problem of reopen, that during reopen the whole tree
>> may be moved to another aio context, but we continue operations with
>> acquired old aio context which is wrong).
> Do we even acquire the old AioContext?
>
I think, I mean aio_context_acquire(ctx); in current qmp_x_blockdev_reopen()..
And I remember, that you said about that problem. Still, may be I misunderstood (or misremember). Doesn't worth digging, I'd prefer just review v5 with a fresh eye when it comes.
--
Best regards,
Vladimir
next prev parent reply other threads:[~2021-05-06 9:31 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-17 17:15 [PATCH v4 0/6] Allow changing bs->file on reopen Alberto Garcia
2021-03-17 17:15 ` [PATCH v4 1/6] block: Add bdrv_reopen_queue_free() Alberto Garcia
2021-03-18 13:32 ` Vladimir Sementsov-Ogievskiy
2021-03-17 17:15 ` [PATCH v4 2/6] block: Allow changing bs->file on reopen Alberto Garcia
2021-03-18 14:25 ` Vladimir Sementsov-Ogievskiy
2021-03-24 12:25 ` Alberto Garcia
2021-03-24 15:08 ` Vladimir Sementsov-Ogievskiy
2021-05-05 13:58 ` Kevin Wolf
2021-05-07 7:11 ` Vladimir Sementsov-Ogievskiy
2021-05-07 14:09 ` Kevin Wolf
2021-05-10 9:26 ` Vladimir Sementsov-Ogievskiy
2021-03-17 17:15 ` [PATCH v4 3/6] iotests: Test replacing files with x-blockdev-reopen Alberto Garcia
2021-05-05 15:57 ` Kevin Wolf
2021-03-17 17:15 ` [PATCH v4 4/6] block: Support multiple reopening " Alberto Garcia
2021-03-18 14:45 ` Vladimir Sementsov-Ogievskiy
2021-05-05 16:18 ` Kevin Wolf
2021-05-06 9:21 ` Vladimir Sementsov-Ogievskiy [this message]
2021-03-17 17:15 ` [PATCH v4 5/6] iotests: Test reopening multiple devices at the same time Alberto Garcia
2021-03-17 17:15 ` [PATCH v4 6/6] block: Make blockdev-reopen stable API Alberto Garcia
2021-05-14 15:53 ` [PATCH v4 0/6] Allow changing bs->file on reopen Vladimir Sementsov-Ogievskiy
2021-06-09 15:53 ` Kevin Wolf
2021-06-09 16:40 ` Vladimir Sementsov-Ogievskiy
2021-06-10 12:10 ` Vladimir Sementsov-Ogievskiy
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