Commit 0f39ac9a authored by Max Reitz's avatar Max Reitz Committed by Stefan Hajnoczi
Browse files

qcow2: Correct snapshots size for overlap check 



Using s->snapshots_size instead of snapshots_size for the metadata
overlap check in qcow2_write_snapshots leads to the detection of an
overlap with the main qcow2 image header when deleting the last
snapshot, since s->snapshots_size has not yet been updated and is
therefore non-zero. However, the offset returned by qcow2_alloc_clusters
will be zero since snapshots_size is zero. Therefore, an overlap is
detected albeit no such will occur.

This patch fixes this by replacing s->snapshots_size by snapshots_size
when calling qcow2_pre_write_overlap_check.

Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent a9031675

block/qcow2-snapshot.c

+1 −1
Original line number Diff line number Diff line
@@ -192,7 +192,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs) 
    /* The snapshot list position has not yet been updated, so these clusters

     * must indeed be completely free */

    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset,

                                        s->snapshots_size);

                                        snapshots_size);

    if (ret < 0) {

        return ret;

    }