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| 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 | |
| parent | 2118771ddf27dbfd6fb0b1e611423aa6cd72e160 (diff) | |
| download | qemu-7bbb59202a538b12df5840f250899ac3ec39a069.zip qemu-7bbb59202a538b12df5840f250899ac3ec39a069.tar.gz qemu-7bbb59202a538b12df5840f250899ac3ec39a069.tar.bz2 | |
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>
| -rw-r--r-- | block/qcow2-cluster.c | 14 | ||||
| -rwxr-xr-x | tests/qemu-iotests/061 | 6 | ||||
| -rw-r--r-- | tests/qemu-iotests/061.out | 5 |
3 files changed, 23 insertions, 2 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index fd506b4c..996b331 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; } diff --git a/tests/qemu-iotests/061 b/tests/qemu-iotests/061 index 08ddbdd..5747beb 100755 --- a/tests/qemu-iotests/061 +++ b/tests/qemu-iotests/061 @@ -304,6 +304,12 @@ _img_info --format-specific _check_test_img echo +echo "=== Testing version downgrade with extended L2 entries ===" +echo +_make_test_img -o "compat=1.1,extended_l2=on" 64M +$QEMU_IMG amend -o "compat=0.10" "$TEST_IMG" + +echo echo "=== Try changing the external data file ===" echo _make_test_img -o "compat=1.1" 64M diff --git a/tests/qemu-iotests/061.out b/tests/qemu-iotests/061.out index b0a1382..ee30da2 100644 --- a/tests/qemu-iotests/061.out +++ b/tests/qemu-iotests/061.out @@ -533,6 +533,11 @@ Format specific information: extended l2: false No errors were found on the image. +=== Testing version downgrade with extended L2 entries === + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qemu-img: Cannot downgrade an image with incompatible features 0x10 set + === Try changing the external data file === Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 |