From b0ddcbbb36a66a605eb232b905cb49b1cc72e74e Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 6 Jul 2018 18:41:07 +0200 Subject: block: Fix copy-on-read crash with partial final cluster If the virtual disk size isn't aligned to full clusters, bdrv_co_do_copy_on_readv() may get pnum == 0 before having the full cluster completed, which will let it run into an assertion failure: qemu-io: block/io.c:1203: bdrv_co_do_copy_on_readv: Assertion `skip_bytes < pnum' failed. Check for EOF, assert that we read at least as much as the read request originally wanted to have (which is true at EOF because otherwise bdrv_check_byte_request() would already have returned an error) and return success early even though we couldn't copy the full cluster. Signed-off-by: Kevin Wolf --- tests/qemu-iotests/197 | 9 +++++++++ tests/qemu-iotests/197.out | 8 ++++++++ 2 files changed, 17 insertions(+) (limited to 'tests/qemu-iotests') diff --git a/tests/qemu-iotests/197 b/tests/qemu-iotests/197 index 3ae4975..0369aa5 100755 --- a/tests/qemu-iotests/197 +++ b/tests/qemu-iotests/197 @@ -109,6 +109,15 @@ $QEMU_IO -f qcow2 -c map "$TEST_WRAP" _check_test_img $QEMU_IMG compare -f $IMGFMT -F qcow2 "$TEST_IMG" "$TEST_WRAP" +echo +echo '=== Partial final cluster ===' +echo + +_make_test_img 1024 +$QEMU_IO -f $IMGFMT -C -c 'read 0 1024' "$TEST_IMG" | _filter_qemu_io +$QEMU_IO -f $IMGFMT -c map "$TEST_IMG" +_check_test_img + # success, all done echo '*** done' status=0 diff --git a/tests/qemu-iotests/197.out b/tests/qemu-iotests/197.out index 52b4137..8febda5 100644 --- a/tests/qemu-iotests/197.out +++ b/tests/qemu-iotests/197.out @@ -23,4 +23,12 @@ can't open device TEST_DIR/t.wrap.qcow2: Can't use copy-on-read on read-only dev 1023.938 MiB (0x3fff0000) bytes not allocated at offset 3 GiB (0xc0010000) No errors were found on the image. Images are identical. + +=== Partial final cluster === + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1024 +read 1024/1024 bytes at offset 0 +1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +1 KiB (0x400) bytes allocated at offset 0 bytes (0x0) +No errors were found on the image. *** done -- cgit v1.1