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From: Max Reitz <mreitz@redhat.com>
To: Eric Blake <eblake@redhat.com>, qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-devel@nongnu.org
Subject: Re: [PATCH v3 04/16] qcow2: Keep unknown extra snapshot data
Date: Mon, 14 Oct 2019 10:46:24 +0200	[thread overview]
Message-ID: <2831d94c-eb4f-00c8-a462-029a3403d79a@redhat.com> (raw)
In-Reply-To: <8ecf3ce6-51e4-63ee-8fdc-945ca3e1f397@redhat.com>


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On 11.10.19 18:20, Eric Blake wrote:
> On 10/11/19 10:28 AM, Max Reitz wrote:
>> The qcow2 specification says to ignore unknown extra data fields in
>> snapshot table entries.  Currently, we discard it whenever we update the
>> image, which is a bit different from "ignore".
>>
>> This patch makes the qcow2 driver keep all unknown extra data fields
>> when updating an image's snapshot table.
>>
>> Signed-off-by: Max Reitz <mreitz@redhat.com>
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>> ---
> 
>>   /* Bitmap header extension constraints */
>>   #define QCOW2_MAX_BITMAPS 65535
>>   #define QCOW2_MAX_BITMAP_DIRECTORY_SIZE (1024 * QCOW2_MAX_BITMAPS)
>> @@ -181,6 +184,8 @@ typedef struct QCowSnapshot {
>>       uint32_t date_sec;
>>       uint32_t date_nsec;
>>       uint64_t vm_clock_nsec;
>> +    uint32_t extra_data_size;
>> +    void *unknown_extra_data; /* Extra data past
>> QCowSnapshotExtraData */
> 
> Would it be worth a comment change:
> 
> uint32_t extra_data_size; /* Size of all extra data, including
> QCowSnapshotExtraData */
> void *unknown_extra_data; /* Data beyond QCowSnapshotExtraData, if any */
> 
> Either way, R-b stands.

Can’t hurt.  Well, except that extra_data_size may or may not include
QCowSnapshotExtraData, because maybe it isn’t fully present in the image.

Max


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  reply	other threads:[~2019-10-14  8:49 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-11 15:27 [PATCH v3 00/16] qcow2: Let check -r all repair some snapshot bits Max Reitz
2019-10-11 15:27 ` [PATCH v3 01/16] include: Move endof() up from hw/virtio/virtio.h Max Reitz
2019-10-11 15:28 ` [PATCH v3 02/16] qcow2: Use endof() Max Reitz
2019-10-11 15:28 ` [PATCH v3 03/16] qcow2: Add Error ** to qcow2_read_snapshots() Max Reitz
2019-10-11 15:28 ` [PATCH v3 04/16] qcow2: Keep unknown extra snapshot data Max Reitz
2019-10-11 16:20   ` Eric Blake
2019-10-14  8:46     ` Max Reitz [this message]
2019-10-11 15:28 ` [PATCH v3 05/16] qcow2: Make qcow2_write_snapshots() public Max Reitz
2019-10-11 15:28 ` [PATCH v3 06/16] qcow2: Put qcow2_upgrade() into its own function Max Reitz
2019-10-11 15:28 ` [PATCH v3 07/16] qcow2: Write v3-compliant snapshot list on upgrade Max Reitz
2019-10-11 16:23   ` Eric Blake
2019-10-14  8:45     ` Max Reitz
2019-10-14 13:53       ` Eric Blake
2019-10-14 14:09         ` Max Reitz
2019-10-11 15:28 ` [PATCH v3 08/16] qcow2: Separate qcow2_check_read_snapshot_table() Max Reitz
2019-10-11 15:28 ` [PATCH v3 09/16] qcow2: Add qcow2_check_fix_snapshot_table() Max Reitz
2019-10-11 15:28 ` [PATCH v3 10/16] qcow2: Fix broken snapshot table entries Max Reitz
2019-10-11 15:28 ` [PATCH v3 11/16] qcow2: Keep track of the snapshot table length Max Reitz
2019-10-11 15:28 ` [PATCH v3 12/16] qcow2: Fix overly long snapshot tables Max Reitz
2019-10-11 15:28 ` [PATCH v3 13/16] qcow2: Repair snapshot table with too many entries Max Reitz
2019-10-11 16:31   ` Eric Blake
2019-10-11 15:28 ` [PATCH v3 14/16] qcow2: Fix v3 snapshot table entry compliancy Max Reitz
2019-10-11 16:32   ` Eric Blake
2019-10-11 15:28 ` [PATCH v3 15/16] iotests: Add peek_file* functions Max Reitz
2019-10-11 15:28 ` [PATCH v3 16/16] iotests: Test qcow2's snapshot table handling Max Reitz
2019-10-28 10:55 ` [PATCH v3 00/16] qcow2: Let check -r all repair some snapshot bits Max Reitz

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