Re: [Qemu-devel] [PATCH 0/2] block/file-posix: Fix xfs_write_zeroes()

[Paolo Bonzini]

On 22/08/19 18:26, Max Reitz wrote:
> Lukàš ran over a nasty regression in our xfs_write_zeroes() function
> (sorry, my fault) made apparent by a recent patch from Anton that makes
> qcow2 images heavily exercise the offending code path.
> 
> This series fixes the bug and adds a test to prevent it from
> reoccurring.
> 
> 
> Max Reitz (2):
>   block/file-posix: Fix xfs_write_zeroes()
>   iotests: Test reverse sub-cluster qcow2 writes
> 
>  block/file-posix.c         | 16 ++++++---
>  tests/qemu-iotests/265     | 67 ++++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/265.out |  6 ++++
>  tests/qemu-iotests/group   |  1 +
>  4 files changed, 85 insertions(+), 5 deletions(-)
>  create mode 100755 tests/qemu-iotests/265
>  create mode 100644 tests/qemu-iotests/265.out
> 

What about just killing libxfs support and only use fallocate?
FALLOC_FL_ZERO_RANGE was added in Linux 3.15 (2014) and the only
platform we probably support with such an old kernel is of course
RHEL/CentOS 7 which has had it backported.

Paolo