xemu/tests/qemu-iotests/039.out
Kevin Wolf 4c2e5f8f46 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>
2014-04-04 14:12:26 +02:00

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QA output created by 039
== Checking that image is clean on shutdown ==
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728
wrote 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
incompatible_features 0x0
No errors were found on the image.
== Creating a dirty image file ==
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728
wrote 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
incompatible_features 0x1
ERROR cluster 5 refcount=0 reference=1
ERROR OFLAG_COPIED data cluster: l2_entry=8000000000050000 refcount=0
2 errors were found on the image.
Data may be corrupted, or further writes to the image may corrupt it.
== Read-only access must still work ==
read 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
incompatible_features 0x1
== Repairing the image file must succeed ==
Repairing cluster 5 refcount=0 reference=1
The following inconsistencies were found and repaired:
0 leaked clusters
1 corruptions
Double checking the fixed image now...
No errors were found on the image.
incompatible_features 0x0
== Data should still be accessible after repair ==
read 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
== Opening a dirty image read/write should repair it ==
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728
wrote 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
incompatible_features 0x1
Repairing cluster 5 refcount=0 reference=1
wrote 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
incompatible_features 0x0
== Creating an image file with lazy_refcounts=off ==
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728
wrote 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
incompatible_features 0x0
No errors were found on the image.
== Committing to a backing file with lazy_refcounts=on ==
Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=134217728
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 backing_file='TEST_DIR/t.IMGFMT.base'
wrote 512/512 bytes at offset 0
512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
Image committed.
incompatible_features 0x0
incompatible_features 0x0
No errors were found on the image.
No errors were found on the image.
*** done