Re: [Qemu-block] [PATCH 1/5 for-2.11?] qcow2: reject unaligned offsets in write compressed

[Anton Nefedov]

On 14/11/2017 7:50 PM, Eric Blake wrote:
> On 11/14/2017 04:16 AM, Anton Nefedov wrote:
> > Misaligned compressed write is not supported.
> >
> > Signed-off-by: Anton Nefedov <address@hidden>
> > ---
> >   block/qcow2.c | 4 ++++
> >   1 file changed, 4 insertions(+)
>
> Should this one be applied in 2.11?

For the record, this one is pretty hard to trigger; backup and qemu-img
convert currently use compressed write, both make sure they operate in
clusters.

qemu-io is almighty though

qemu-io> write -c -P 7 512 64k
wrote 65536/65536 bytes at offset 512
64 KiB, 1 ops; 0.0187 sec (3.329 MiB/sec and 53.2566 ops/sec)
qemu-io> read -P 7 512 64k
Pattern verification failed at offset 512, 65536 bytes
read 65536/65536 bytes at offset 512
64 KiB, 1 ops; 0.0002 sec (248.016 MiB/sec and 3968.2540 ops/sec)
qemu-io> read -P 7 0 64k
read 65536/65536 bytes at offset 0
64 KiB, 1 ops; 0.0000 sec (1.606 GiB/sec and 26315.7895 ops/sec)

/Anton