diff options
| author | Alberto Garcia <berto@igalia.com> | 2020-07-10 18:13:15 +0200 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2020-08-25 10:20:15 +0200 |
| commit | 7bbb59202a538b12df5840f250899ac3ec39a069 (patch) | |
| tree | 5c4553f0bd93e72d1e63cbb3ab45f109f5024893 /block | |
| parent | 2118771ddf27dbfd6fb0b1e611423aa6cd72e160 (diff) | |
qcow2: Assert that expand_zero_clusters_in_l1() does not support subclusters
This function is only used by qcow2_expand_zero_clusters() to
downgrade a qcow2 image to a previous version. This would require
transforming all extended L2 entries into normal L2 entries but this
is not a simple task and there are no plans to implement this at the
moment.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <15e65112b4144381b4d8c0bdf8fb76b0d813e3d1.1594396418.git.berto@igalia.com>
[mreitz: Fixed comment style]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/qcow2-cluster.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index fd506b4cb3..996b3314f4 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -2166,6 +2166,9 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table, int ret; int i, j; + /* qcow2_downgrade() is not allowed in images with subclusters */ + assert(!has_subclusters(s)); + slice_size2 = s->l2_slice_size * l2_entry_size(s); n_slices = s->cluster_size / slice_size2; @@ -2233,8 +2236,11 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table, if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) { if (!bs->backing) { - /* not backed; therefore we can simply deallocate the - * cluster */ + /* + * not backed; therefore we can simply deallocate the + * cluster. No need to call set_l2_bitmap(), this + * function doesn't support images with subclusters. + */ set_l2_entry(s, l2_slice, j, 0); l2_dirty = true; continue; @@ -2305,6 +2311,10 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table, } else { set_l2_entry(s, l2_slice, j, offset); } + /* + * No need to call set_l2_bitmap() after set_l2_entry() because + * this function doesn't support images with subclusters. + */ l2_dirty = true; } |