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Re: [Qemu-devel] [PATCH v2 16/16] iotests: Test qcow2's snapshot table h
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH v2 16/16] iotests: Test qcow2's snapshot table handling |
Date: |
Mon, 19 Aug 2019 15:25:28 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 |
On 8/19/19 1:56 PM, Max Reitz wrote:
> Add a test how our qcow2 driver handles extra data in snapshot table
> entries, and how it repairs overly long snapshot tables.
>
> Signed-off-by: Max Reitz <address@hidden>
> ---
> +++ b/tests/qemu-iotests/261.out
> @@ -0,0 +1,346 @@
> +QA output created by 261
> +
> +=== Create v2 template ===
> +
> +Formatting 'TEST_DIR/t.IMGFMT.v2.orig', fmt=IMGFMT size=67108864
> +No errors were found on the image.
> +Snapshots in TEST_DIR/t.IMGFMT.v2.orig:
> + [0]
> + ID: 1
> + Name: sn0
> + Extra data size: 0
> + [1]
> + ID: 2
> + Name: sn1
> + Extra data size: 42
> + VM state size: 0
> + Disk size: 67108864
> + Unknown extra data: very important data
Hmm - possibly one more patch to write - but when checking snapshots for
accuracy, do we want to insist that the 32-bit truncated VM state size
is either 0 or matches the low 32-bits of the 64-bit VM state size
field? Any mismatch between those fields (other than the 32-bit field
being left 0 because we knew to use the 64-bit field) might be a hint of
a possible corruption. But there's no good way to correct it other than
wiping the 32-bit field to 0; and for a v2 image, any change we make to
the 32-bit field might actually make the snapshot unusable for an older
client that doesn't know how to use the 64-bit field. So maybe we just
overlook that.
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
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- Re: [Qemu-devel] [PATCH v2 12/16] qcow2: Fix overly long snapshot tables, (continued)
[Qemu-devel] [PATCH v2 13/16] qcow2: Repair snapshot table with too many entries, Max Reitz, 2019/08/19
[Qemu-devel] [PATCH v2 14/16] qcow2: Fix v3 snapshot table entry compliancy, Max Reitz, 2019/08/19
[Qemu-devel] [PATCH v2 15/16] iotests: Add peek_file* functions, Max Reitz, 2019/08/19
[Qemu-devel] [PATCH v2 16/16] iotests: Test qcow2's snapshot table handling, Max Reitz, 2019/08/19
- Re: [Qemu-devel] [PATCH v2 16/16] iotests: Test qcow2's snapshot table handling,
Eric Blake <=