| Message ID | 1379586555-1479-1-git-send-email-mreitz@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Sep 19, 2013 at 12:29:15PM +0200, Max Reitz wrote: > 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: Max Reitz <mreitz@redhat.com> > --- > block/qcow2-snapshot.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Thanks, applied to my block tree: https://github.com/stefanha/qemu/commits/block Stefan
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 7d14420..5e8a779 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -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; }
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: Max Reitz <mreitz@redhat.com> --- block/qcow2-snapshot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)