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| author | Kevin Wolf <kwolf@redhat.com> | 2014-04-03 13:47:50 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2014-04-04 14:12:26 +0200 |
| commit | 4c2e5f8f46a17966dc45b5a3e07b97434c0eabdf (patch) | |
| tree | aa545165b570b6c297d75dd0ae623abd3861e4f1 /tests/qemu-iotests/039 | |
| parent | cbee81f6de57ddc1b21ba28f01f6a3b5d87428a5 (diff) | |
| download | qemu-4c2e5f8f46a17966dc45b5a3e07b97434c0eabdf.tar.gz | |
qcow2: Flush metadata during read-only reopen
If lazy refcounts are enabled for a backing file, committing to this
backing file may leave it in a dirty state even if the commit succeeds.
The reason is that the bdrv_flush() call in bdrv_commit() doesn't flush
refcount updates with lazy refcounts enabled, and qcow2_reopen_prepare()
doesn't take care to flush metadata.
In order to fix this, this patch also fixes qcow2_mark_clean(), which
contains another ineffective bdrv_flush() call beause lazy refcounts are
disabled only afterwards. All existing callers of qcow2_mark_clean()
either don't modify refcounts or already flush manually, so that this
fixes only a latent, but not yet actually triggerable bug.
Another instance of the same problem is live snapshots. Again, a real
corruption is prevented by an explicit flush for non-read-only images in
external_snapshot_prepare(), but images using lazy refcounts stay dirty.
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'tests/qemu-iotests/039')
| -rwxr-xr-x | tests/qemu-iotests/039 | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/tests/qemu-iotests/039 b/tests/qemu-iotests/039 index 9b355c0977..b9cbe99560 100755 --- a/tests/qemu-iotests/039 +++ b/tests/qemu-iotests/039 @@ -131,6 +131,26 @@ ulimit -c "$old_ulimit" ./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features _check_test_img +echo +echo "== Committing to a backing file with lazy_refcounts=on ==" + +IMGOPTS="compat=1.1,lazy_refcounts=on" +TEST_IMG="$TEST_IMG".base _make_test_img $size + +IMGOPTS="compat=1.1,lazy_refcounts=on,backing_file=$TEST_IMG.base" +_make_test_img $size + +$QEMU_IO -c "write 0 512" "$TEST_IMG" | _filter_qemu_io +$QEMU_IMG commit "$TEST_IMG" + +# The dirty bit must not be set +./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features +./qcow2.py "$TEST_IMG".base dump-header | grep incompatible_features + +_check_test_img +TEST_IMG="$TEST_IMG".base _check_test_img + + # success, all done echo "*** done" rm -f $seq.full |