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From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: Alberto Garcia <berto@igalia.com>, Kevin Wolf <kwolf@redhat.com>,
	qemu-block@nongnu.org
Cc: qemu-devel@nongnu.org, mreitz@redhat.com
Subject: Re: [PATCH v4 4/9] qcow2: Support BDRV_REQ_ZERO_WRITE for truncate
Date: Tue, 21 Apr 2020 14:19:09 +0300	[thread overview]
Message-ID: <a75a7331-9638-3453-9c0e-9cc337583103@virtuozzo.com> (raw)
In-Reply-To: <w51wo699kpj.fsf@maestria.local.igalia.com>

21.04.2020 13:50, Alberto Garcia wrote:
> On Tue 21 Apr 2020 10:47:17 AM CEST, Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> wrote:
>>> +    if ((flags & BDRV_REQ_ZERO_WRITE) && offset > old_length) {
>>> +        ret = qcow2_cluster_zeroize(bs, old_length, offset - old_length, 0);
>>
>> Hmm. As I understand, qcow2_cluster_zeroize is unprepared to
>> cluster-unaligned offset/size. I think we should handle it somehow.
> 
> You're right, it actually hits an assertion :-/
> 
> I suppose you can simply round the size up to the next cluster.
> 


But we also need to handle unaligned old_length, we can't just align it down, we should write zero to existing cluster if it is NORMAL cluster..


-- 
Best regards,
Vladimir


  reply	other threads:[~2020-04-21 11:20 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-20 13:32 [PATCH v4 0/9] block: Fix resize (extending) of short overlays Kevin Wolf
2020-04-20 13:32 ` [PATCH v4 1/9] block: Add flags to BlockDriver.bdrv_co_truncate() Kevin Wolf
2020-04-20 13:57   ` Alberto Garcia
2020-04-21  8:15   ` Vladimir Sementsov-Ogievskiy
2020-04-20 13:32 ` [PATCH v4 2/9] block: Add flags to bdrv(_co)_truncate() Kevin Wolf
2020-04-20 13:58   ` Alberto Garcia
2020-04-21  8:25   ` Vladimir Sementsov-Ogievskiy
2020-04-20 13:32 ` [PATCH v4 3/9] block-backend: Add flags to blk_truncate() Kevin Wolf
2020-04-20 13:59   ` Alberto Garcia
2020-04-21  8:33   ` Vladimir Sementsov-Ogievskiy
2020-04-20 13:32 ` [PATCH v4 4/9] qcow2: Support BDRV_REQ_ZERO_WRITE for truncate Kevin Wolf
2020-04-20 14:02   ` Alberto Garcia
2020-04-21  8:47   ` Vladimir Sementsov-Ogievskiy
2020-04-21 10:50     ` Alberto Garcia
2020-04-21 11:19       ` Vladimir Sementsov-Ogievskiy [this message]
2020-04-20 13:32 ` [PATCH v4 5/9] raw-format: " Kevin Wolf
2020-04-20 14:03   ` Alberto Garcia
2020-04-20 15:14   ` Eric Blake
2020-04-20 15:32     ` Kevin Wolf
2020-04-20 15:53       ` Eric Blake
2020-04-20 13:32 ` [PATCH v4 6/9] file-posix: " Kevin Wolf
2020-04-20 14:05   ` Alberto Garcia
2020-04-21 10:56   ` Vladimir Sementsov-Ogievskiy
2020-04-20 13:32 ` [PATCH v4 7/9] block: truncate: Don't make backing file data visible Kevin Wolf
2020-04-20 14:10   ` Alberto Garcia
2020-04-21 11:19   ` Vladimir Sementsov-Ogievskiy
2020-04-20 13:32 ` [PATCH v4 8/9] iotests: Filter testfiles out in img_info_log() Kevin Wolf
2020-04-21 11:34   ` Vladimir Sementsov-Ogievskiy
2020-04-20 13:32 ` [PATCH v4 9/9] iotests: Test committing to short backing file Kevin Wolf
2020-04-21 11:39   ` Vladimir Sementsov-Ogievskiy
2020-04-20 23:49 ` [PATCH v4 0/9] block: Fix resize (extending) of short overlays no-reply

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