[PATCH 0/2] btrfs: disable inline checksum for multi-dev striped FS

[Naohiro Aota <naohiro.aota@wdc.com>]

There was a report of write performance regression on 6.5-rc4 on RAID0
(4 devices) btrfs [1]. Then, I reported that BTRFS_FS_CSUM_IMPL_FAST
and doing the checksum inline can be bad for performance on RAID0
setup [2]. 

[1] https://lore.kernel.org/linux-btrfs/20230731152223.4EFB.409509F4@e16-tech.com/
[2] https://lore.kernel.org/linux-btrfs/p3vo3g7pqn664mhmdhlotu5dzcna6vjtcoc2hb2lsgo2fwct7k@xzaxclba5tae/

While inlining the fast checksum is good for single (or two) device,
but it is not fast enough for multi-device striped writing.

So, this series first introduces fs_devices->inline_csum_mode and its
sysfs interface to tweak the inline csum behavior (auto/on/off). Then,
it disables inline checksum when it find a block group striped writing
into multiple devices.

Naohiro Aota (2):
  btrfs: introduce inline_csum_mode to tweak inline checksum behavior
  btrfs: detect multi-dev stripe and disable automatic inline checksum

 fs/btrfs/bio.c     | 14 ++++++++++++--
 fs/btrfs/sysfs.c   | 39 +++++++++++++++++++++++++++++++++++++++
 fs/btrfs/volumes.c | 20 ++++++++++++++++++++
 fs/btrfs/volumes.h | 21 +++++++++++++++++++++
 4 files changed, 92 insertions(+), 2 deletions(-)

-- 
2.43.0