Commit 791fff50 authored by Max Reitz's avatar Max Reitz
Browse files

qcow2: check_errors are fatal 



When trying to repair a dirty image, qcow2_check() may apparently
succeed (no really fatal error occurred that would prevent the check
from continuing), but if check_errors in the result object is non-zero,
we cannot trust the image to be usable.

Reported-by: default avatarR. Nageswara Sastry <nasastry@in.ibm.com>
Buglink: https://bugs.launchpad.net/qemu/+bug/1728639


Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
Message-id: 20171110203111.7666-2-mreitz@redhat.com
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent 3e3b838f

block/qcow2.c

+4 −1
Original line number Diff line number Diff line
@@ -1477,7 +1477,10 @@ static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags, 
        BdrvCheckResult result = {0};



        ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS);

        if (ret < 0) {

        if (ret < 0 || result.check_errors) {

            if (ret >= 0) {

                ret = -EIO;

            }

            error_setg_errno(errp, -ret, "Could not repair dirty image");

            goto fail;

        }

tests/qemu-iotests/060

+20 −0
Original line number Diff line number Diff line
@@ -301,6 +301,26 @@ _make_test_img 64M 
poke_file "$TEST_IMG" "48"                "\x00\x00\x00\x00\x00\x00\x00\x00"

$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io



echo

echo "=== Testing dirty corrupt image ==="

echo



_make_test_img 64M



# Let the refblock appear unaligned

poke_file "$TEST_IMG" "$rt_offset"        "\x00\x00\x00\x00\xff\xff\x2a\x00"

# Mark the image dirty, thus forcing an automatic check when opening it

poke_file "$TEST_IMG" 72 "\x00\x00\x00\x00\x00\x00\x00\x01"

# Open the image (qemu should refuse to do so)

$QEMU_IO -c close "$TEST_IMG" 2>&1 | _filter_testdir | _filter_imgfmt



echo '--- Repairing ---'



# The actual repair should have happened (because of the dirty bit),

# but some cleanup may have failed (like freeing the old reftable)

# because the image was already marked corrupt by that point

_check_test_img -r all



# success, all done

echo "*** done"

rm -f $seq.full

tests/qemu-iotests/060.out

+23 −0
Original line number Diff line number Diff line
@@ -284,4 +284,27 @@ No errors were found on the image. 
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864

qcow2: Marking image as corrupt: Preventing invalid allocation of L2 table at offset 0; further corruption events will be suppressed

write failed: Input/output error



=== Testing dirty corrupt image ===



Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864

ERROR refcount block 0 is not cluster aligned; refcount table entry corrupted

IMGFMT: Marking image as corrupt: Refblock offset 0xffff2a00 unaligned (reftable index: 0); further corruption events will be suppressed

Can't get refcount for cluster 0: Input/output error

Can't get refcount for cluster 1: Input/output error

Can't get refcount for cluster 2: Input/output error

Can't get refcount for cluster 3: Input/output error

Rebuilding refcount structure

Repairing cluster 1 refcount=1 reference=0

can't open device TEST_DIR/t.IMGFMT: Could not repair dirty image: Input/output error

--- Repairing ---

Leaked cluster 1 refcount=1 reference=0

Repairing cluster 1 refcount=1 reference=0

The following inconsistencies were found and repaired:



    1 leaked clusters

    0 corruptions



Double checking the fixed image now...

No errors were found on the image.

*** done