On 7/30/19 12:25 PM, Max Reitz wrote: > The only case where we currently reject snapshot table entries is when > they have too much extra data. Fix them with qemu-img check -r all by > counting it as a corruption, reducing their extra_data_size, and then > letting qcow2_check_fix_snapshot_table() do the rest. > > Signed-off-by: Max Reitz <mre...@redhat.com> > --- > block/qcow2-snapshot.c | 69 ++++++++++++++++++++++++++++++++++-------- > 1 file changed, 56 insertions(+), 13 deletions(-) >
> @@ -112,16 +141,22 @@ int qcow2_read_snapshots(BlockDriverState *bs, Error
> **errp)
> }
>
> if (sn->extra_data_size > sizeof(extra)) {
> - /* Store unknown extra data */
> size_t unknown_extra_data_size =
> sn->extra_data_size - sizeof(extra);
>
> - sn->unknown_extra_data = g_malloc(unknown_extra_data_size);
> - ret = bdrv_pread(bs->file, offset, sn->unknown_extra_data,
> - unknown_extra_data_size);
> - if (ret < 0) {
> - error_setg_errno(errp, -ret, "Failed to read snapshot
> table");
> - goto fail;
> + if (discard_unknown_extra_data) {
> + /* Discard unknown extra data */
> + sn->extra_data_size = sizeof(extra);
This truncates it down to just the data we know. Should it instead
truncate down to the 1024 bytes of QCOW_MAX_SNAPSHOT_EXTRA_DATA defined
in 2/13? (We can't keep all of the user's extra stuff, but we can at
least try to preserve as much as possible)
Otherwise, looks good.
Reviewed-by: Eric Blake <ebl...@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
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