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>
The moved OFLAG_COPIED check in qcow2_check_refcounts results in a
different output from test 039 (mismatches are now found after the
general refcount check (as far as any remain)). This patch adjusts the
expected test result accordingly.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Image formats with a dirty bit, like qed and qcow2, repair dirty image
files upon open with BDRV_O_RDWR. Performing automatic repair when
qemu-img check runs is not ideal because the bdrv_open() call repairs
the image before the actual bdrv_check() call from qemu-img.c.
Fix this "double repair" since it leads to confusing output from
qemu-img check. Tell the block driver that this image is being opened
just for bdrv_check(). This skips automatic repair and qemu-img.c can
invoke it manually with bdrv_check().
Update the golden output for qemu-iotests 039 to reflect the new
qemu-img check output.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qemu-iotests already filters out image creation options that may be
present or not in order to get the same output in both cases. However,
often it only considers the default value of the option. Cover all valid
values instead so that ./check -o name=value can be used successfull for
all of them.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This tests establishes the basic post-conditions of the qcow2 lazy
refcounts features:
1. If the image was closed normally, it is marked clean.
2. If an allocating write was performed and the image was not closed
normally, then it is marked dirty.
a. Written data can be read back successfully.
b. The image file can be repaired and will be marked clean again.
c. The image file is automatically repaired when opened read/write.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
