[PATCH STABLE 5.18 0/2] btrfs: raid56 backports to reduce destructive RMW

[Qu Wenruo <wqu@suse.com>]

Hi Greg and Sasha,

This two patches are backports for v5.18 branch.

These two patches are reducing the chance of destructive RMW cycle,
where btrfs can use corrupted data to generate new P/Q, thus making some
repairable data unrepairable.

Those patches are more important than what I initially thought, thus
unfortunately they are not CCed to stable by themselves.

Furthermore due to recent refactors/renames, there are quite some member
change related to those patches, thus have to be manually backported.
(The v5.18 backport is more like the v5.15 backport, with small tweaks
due to member naming change).

One of the fastest way to verify the behavior is the existing btrfs/125
test case from fstests. (not in auto group AFAIK).

Qu Wenruo (2):
  btrfs: only write the sectors in the vertical stripe which has data
    stripes
  btrfs: raid56: don't trust any cached sector in
    __raid56_parity_recover()

 fs/btrfs/raid56.c | 74 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 57 insertions(+), 17 deletions(-)

-- 
2.37.0