[PATCH 0/3] btrfs: remove __GFP_NOFAIL usage for debug builds

[Qu Wenruo <wqu@suse.com>]

This patchset removes all __GFP_NOFAIL flags usage inside btrfs for
DEBUG builds.

There are 3 call sites utilizing __GFP_NOFAIL:

- __alloc_extent_buffer()
  It's for the extent_buffer structure allocation.
  All callers are already handling the errors.

- attach_eb_folio_to_filemap()
  It's for the filemap_add_folio() call, the flag is also passed to mem
  cgroup, which I suspect is not handling larger folio and __GFP_NOFAIL
  correctly, as I'm hitting soft lockups when testing larger folios

  New error handling is added.

- btrfs_alloc_folio_array()
  This is for page allocation for extent buffers.
  All callers are already handling the errors.

Furthermore, to enable more testing while not affecting end users, the
change is only implemented for DEBUG builds.

Qu Wenruo (3):
  btrfs: do not use __GFP_NOFAIL flag for __alloc_extent_buffer()
  btrfs: do not use __GFP_NOFAIL flag for attach_eb_folio_to_filemap()
  btrfs: do not use __GFP_NOFAIL flag for btrfs_alloc_folio_array()

 fs/btrfs/extent_io.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

-- 
2.45.2