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qcow2: Write v3-compliant snapshot list on upgrade

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qcow2 v3 requires every snapshot table entry to have two extra data
fields: The 64-bit VM state size, and the virtual disk size.  Both are
optional for v2 images, so they may not be present.

qcow2_upgrade() therefore should update the snapshot table to ensure all
entries have these extra data fields.

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1727347
Reported-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20191011152814.14791-8-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Max Reitz 2019-10-11 17:28:05 +02:00
parent 722efb0c7c
commit 0a85af351d
1 changed files with 30 additions and 2 deletions
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32
block/qcow2.c
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@ -4922,7 +4922,9 @@ static int qcow2_upgrade(BlockDriverState *bs, int target_version,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
bool need_snapshot_update;
int current_version = s->qcow_version;
int i;
int ret;
/* This is qcow2_upgrade(), not qcow2_downgrade() */
@ -4931,7 +4933,33 @@ static int qcow2_upgrade(BlockDriverState *bs, int target_version,
/* There are no other versions (yet) that you can upgrade to */
assert(target_version == 3);
status_cb(bs, 0, 1, cb_opaque);
status_cb(bs, 0, 2, cb_opaque);
/*
* In v2, snapshots do not need to have extra data. v3 requires
* the 64-bit VM state size and the virtual disk size to be
* present.
* qcow2_write_snapshots() will always write the list in the
* v3-compliant format.
*/
need_snapshot_update = false;
for (i = 0; i < s->nb_snapshots; i++) {
if (s->snapshots[i].extra_data_size <
sizeof_field(QCowSnapshotExtraData, vm_state_size_large) +
sizeof_field(QCowSnapshotExtraData, disk_size))
{
need_snapshot_update = true;
break;
}
}
if (need_snapshot_update) {
ret = qcow2_write_snapshots(bs);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to update the snapshot table");
return ret;
}
}
status_cb(bs, 1, 2, cb_opaque);
s->qcow_version = target_version;
ret = qcow2_update_header(bs);
@ -4940,7 +4968,7 @@ static int qcow2_upgrade(BlockDriverState *bs, int target_version,
error_setg_errno(errp, -ret, "Failed to update the image header");
return ret;
}
status_cb(bs, 1, 1, cb_opaque);
status_cb(bs, 2, 2, cb_opaque);
return 0;
}