[PATCH v3 0/4] xfs: fix a couple sparse chunk alloc problems

[Brian Foster <bfoster@redhat.com>]

Hi all,

Here's v3 of the series to fix the sparse chunk alloc shutdown. The
original report is available here[1].

This is mostly the same fundamental idea as v2, but the implementation
has been slightly reworked. Instead of creating and using a _minleft()
freelist calculation variant, we rework the min freelist helper to
calculate a min and a max for multi-alloc cases. The max is used
appropriately based on allocations that set args->minleft.

Patches 1 and 2 are unchanged from v2. Patch 3 is new and refactors the
semantics of xfs_alloc_min_freelist() as described above. Patch 4 is the
same general fix as v2, but rather than create its own helper the max
value is passed along with the min and they are used appropriately for
length checks and available space calculations.

I've also since realized that XFS_DEBUG seems to be what defeats the
custom reproducer, for whatever reason, so I can confirm this still
survives that test on !DEBUG. Otherwise the series survives fstests
without regression.

Thoughts, reviews, flames appreciated.

Brian

v3:
- Added patch 3 to refactor xfs_alloc_min_freelist() and calculate
  min/max.
- Updated patch 4 to use the max value for space available and longest
  extent checks.
v2: https://lore.kernel.org/linux-xfs/20260814132239.271492-1-bfoster@redhat.com/
- Reworked fix logic into allocator instead of sparse inode alloc
  specific.
- Dropped Fixes: tag since this is no longer directly correlated to
  sparse inodes.
v1: https://lore.kernel.org/linux-xfs/20260731163337.152522-1-bfoster@redhat.com/

[1] https://lore.kernel.org/linux-xfs/20260717130429.1838767-1-matt@readmodwrite.com/

Brian Foster (4):
  xfs: set minleft correctly for sparse chunk errortag allocation
  xfs: support additional levels in the agfl minimum calculation
  xfs: calculate AGFL max to support multiple-alloc transactions
  xfs: incorporate increased AGFL min requirement for minleft allocs

 fs/xfs/libxfs/xfs_alloc.c  | 106 +++++++++++++++++++++++++++----------
 fs/xfs/libxfs/xfs_alloc.h  |   7 +--
 fs/xfs/libxfs/xfs_bmap.c   |   7 ++-
 fs/xfs/libxfs/xfs_ialloc.c |  14 ++---
 4 files changed, 93 insertions(+), 41 deletions(-)

-- 
2.55.0