On 2018-05-09 22:00, Max Reitz wrote: > Suppose you have an image with consistent OFLAG_COPIED and refcounts. > Now further suppose that image has leaked clusters (single reference, > but refcount 2). When checking such an image with qemu-img check, it > will notify you of the leakage, and that's it. > > Now when trying to repair that image, you naturally use -r leaks because > that should be sufficient and you want to give qemu-img check just as > many "permissions" as it needs so it doesn't destroy your image by > accident. But while the qcow2 driver will fix the refcounts, alas! it > will now complain about OFLAG_COPIED because that should be set now. > However, it will not set that without -r all. So, congratulations, now > you have an image that qemu-img check tells you is really corrupted. > > This series makes -r leaks fix OFLAG_COPIED as well, but only if > repairing the refcounts was completely successful. > > There is a Red Hat Bugzilla entry here: > https://bugzilla.redhat.com/show_bug.cgi?id=1527085 > > ...but I'm afraid the bug description is set to confidential, although I > don't know why. Sorry. :-/ > For everyone who cannot read it, let's say the test case in this series > may very well be a good indication of what you don't see. > > > v2: > - Reworded the comment in patch 2 on why the test does not support > refcount_bits=1 -- it's not just because of the snapshotting, but > mostly because we test OFLAG_COPIED and refcount_bits=1 won't get us > far there [Eric] > > > git-backport-diff against v1: > > Key: > [----] : patches are identical > [####] : number of functional differences between upstream/downstream patch > [down] : patch is downstream-only > The flags [FC] indicate (F)unctional and (C)ontextual differences, > respectively > > 001/2:[----] [--] 'qcow2: Repair OFLAG_COPIED when fixing leaks' > 002/2:[0003] [FC] 'iotests: Repairing error during snapshot deletion' > > > Max Reitz (2): > qcow2: Repair OFLAG_COPIED when fixing leaks > iotests: Repairing error during snapshot deletion > > block/qcow2-refcount.c | 25 ++++++++----- > tests/qemu-iotests/217 | 90 > ++++++++++++++++++++++++++++++++++++++++++++++ > tests/qemu-iotests/217.out | 42 ++++++++++++++++++++++ > tests/qemu-iotests/group | 1 + > 4 files changed, 150 insertions(+), 8 deletions(-) > create mode 100755 tests/qemu-iotests/217 > create mode 100644 tests/qemu-iotests/217.out
Applied to my block branch. Max
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