From: Eric Blake <eblake@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: vsementsov@virtuozzo.com, berto@igalia.com,
qemu-devel@nongnu.org, qemu-block@nongnu.org, mreitz@redhat.com
Subject: Re: [PATCH v5 4/9] qcow2: Support BDRV_REQ_ZERO_WRITE for truncate
Date: Thu, 23 Apr 2020 08:59:12 -0500 [thread overview]
Message-ID: <be3189fa-8120-9bae-166d-f95f5d3a94c7@redhat.com> (raw)
In-Reply-To: <20200423132302.GA23654@linux.fritz.box>
On 4/23/20 8:23 AM, Kevin Wolf wrote:
>>>
>>> So qcow2_cluster_zeroize() seems to accept the unaligned tail. It would
>>> still set the zero flag for the partial last cluster and for the
>>> external data file, bdrv_co_pwrite_zeroes() would have the correct size.
>>
>> Then I'm in favor of NOT rounding the tail. That's an easy enough change
>> and we've now justified that it does what we want, so R-b stands with that
>> one-line tweak.
>
> Would have been too easy... bs->total_sectors isn't updated yet, so the
> assertion does fail.
>
> I can make the assertion check end_offset >= ... instead. That should
> still check what we wanted to check here and allow the unaligned
> extension.
Yes, that works for me.
>
> This feels like the better option to me compared to updating
> bs->total_sectors earlier and then undoing that change in every error
> path.
Indeed.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
next prev parent reply other threads:[~2020-04-23 14:00 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-22 15:21 [PATCH v5 0/9] block: Fix resize (extending) of short overlays Kevin Wolf
2020-04-22 15:21 ` [PATCH v5 1/9] block: Add flags to BlockDriver.bdrv_co_truncate() Kevin Wolf
2020-04-23 9:41 ` Max Reitz
2020-04-23 12:42 ` Kevin Wolf
2020-04-22 15:21 ` [PATCH v5 2/9] block: Add flags to bdrv(_co)_truncate() Kevin Wolf
2020-04-23 10:04 ` Max Reitz
2020-04-22 15:21 ` [PATCH v5 3/9] block-backend: Add flags to blk_truncate() Kevin Wolf
2020-04-23 10:34 ` Max Reitz
2020-04-22 15:21 ` [PATCH v5 4/9] qcow2: Support BDRV_REQ_ZERO_WRITE for truncate Kevin Wolf
2020-04-22 15:33 ` Eric Blake
2020-04-22 15:58 ` Kevin Wolf
2020-04-22 16:14 ` Eric Blake
2020-04-23 13:23 ` Kevin Wolf
2020-04-23 13:59 ` Eric Blake [this message]
2020-04-23 10:53 ` Max Reitz
2020-04-23 13:25 ` Kevin Wolf
2020-04-23 13:56 ` Max Reitz
2020-04-22 15:21 ` [PATCH v5 5/9] raw-format: " Kevin Wolf
2020-04-22 15:34 ` Eric Blake
2020-04-23 10:54 ` Max Reitz
2020-04-22 15:21 ` [PATCH v5 6/9] file-posix: " Kevin Wolf
2020-04-23 10:57 ` Max Reitz
2020-04-22 15:21 ` [PATCH v5 7/9] block: truncate: Don't make backing file data visible Kevin Wolf
2020-04-23 11:14 ` Max Reitz
2020-04-23 13:00 ` Kevin Wolf
2020-04-22 15:21 ` [PATCH v5 8/9] iotests: Filter testfiles out in filter_img_info() Kevin Wolf
2020-04-23 11:24 ` Max Reitz
2020-04-22 15:21 ` [PATCH v5 9/9] iotests: Test committing to short backing file Kevin Wolf
2020-04-23 11:53 ` Max Reitz
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