On Fri, Jul 09, 2021 at 04:49:01PM +0300, Vladimir Sementsov-Ogievskiy wrote: > 09.07.2021 16:16, Eric Blake wrote: > > On Fri, Jul 09, 2021 at 09:33:50AM +0300, Vladimir Sementsov-Ogievskiy > > wrote: > > > > +++ b/tests/qemu-iotests/tests/qemu-img-bitmaps > > > > > > +echo > > > > +echo "=== Check handling of inconsistent bitmap ===" > > > > +echo > > > > + > > > > +$QEMU_IO -c abort "$TEST_IMG" 2>/dev/null > > > > +$QEMU_IMG bitmap --add "$TEST_IMG" b4 > > > > +$QEMU_IMG bitmap --remove "$TEST_IMG" b1 > > > > +_img_info --format-specific | _filter_irrelevant_img_info > > > > +$QEMU_IMG convert --bitmaps -O qcow2 "$TEST_IMG" "$TEST_IMG.copy" > > > > > > Worth then removing remaining inconsistent bitmaps and try again? > > > > > > I think you should now remove $TEST_IMG.copy in _cleanup > > > > $TEST_IMG.copy isn't created on failure (or if it is, that in itself > > is a problem we should be avoiding), > > Seems that's the case:
Oh. Thanks for checking. Yeah, re-reading the code, we don't attempt to copy the bitmaps until after the rest of the convert operation is done. Which means a fix to pre-validate bitmaps before starting the convert requires more code, but may be the right thing (failing at the very end of a long convert attempt, but leaving the file around, is not ideal compared to failing fast). Looks like my v2 will be a bit more beefy. > ./build/qemu-img convert --bitmaps -O qcow2 x y > qemu-img: Failed to populate bitmap b1: Bitmap 'b1' is inconsistent and > cannot be used > Try block-dirty-bitmap-remove to delete this bitmap from disk[root@kvm > master]# > # ls y > y > ./build/qemu-img info y > image: y > file format: qcow2 > virtual size: 1 MiB (1048576 bytes) > disk size: 204 KiB > cluster_size: 65536 > Format specific information: > compat: 1.1 > compression type: zlib > lazy refcounts: false > bitmaps: > [0]: > flags: > name: b1 > granularity: 65536 > refcount bits: 16 > corrupt: false > extended l2: false > > > WOW! It even contains the bitmap not marked in-use. That's a real bug. So we left things dangling with a bitmap that has completely different contents than in the original file. Yeah, that looks like an issue worth improving. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
