Commit 8ac0f15f335 accidently broke the COW of non changed areas
of newly allocated clusters, when the write spans multiple clusters,
and needs COW both prior and after the write.
This results in 'after' COW area beeing encrypted with wrong
sector address, which render it corrupted.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1745922

CC: qemu-stable <qemu-stable@nongnu.org>

Best regards,
	Maxim Levitsky

Maxim Levitsky (3):
  block/qcow2: refactoring of threaded encryption code
  block/qcow2: fix the corruption when rebasing luks encrypted files
  qemu-iotests: test for bz #1745922

 block/qcow2-cluster.c      | 26 +++++++------
 block/qcow2-threads.c      | 53 ++++++++++++++++++++------
 tests/qemu-iotests/263     | 76 ++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/263.out | 19 ++++++++++
 tests/qemu-iotests/group   |  1 +
 5 files changed, 153 insertions(+), 22 deletions(-)
 create mode 100755 tests/qemu-iotests/263
 create mode 100644 tests/qemu-iotests/263.out

-- 
2.17.2

On Fri, 2019-09-06 at 20:31 +0300, Maxim Levitsky wrote:
> Commit 8ac0f15f335 accidently broke the COW of non changed areas
> of newly allocated clusters, when the write spans multiple clusters,
> and needs COW both prior and after the write.
> This results in 'after' COW area beeing encrypted with wrong
> sector address, which render it corrupted.
> 
> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1745922
> 
> CC: qemu-stable <qemu-stable@nongnu.org>

I forgot to mention, huge thanks to Kevin Wolf,
for helping me to define the proper fix for this bug.

Best regards,
	Maxim Levitsky