PF_FSTRANS which is used to avoid transaction reservation recursion, is
dropped since commit 9070733b4efa ("xfs: abstract PF_FSTRANS to
PF_MEMALLOC_NOFS") and commit 7dea19f9ee63 ("mm: introduce
memalloc_nofs_{save,restore} API"), and replaced by PF_MEMALLOC_NOFS which
means to avoid filesystem reclaim recursion.
As these two flags have different meanings, we'd better reintroduce
PF_FSTRANS back. To avoid wasting the space of PF_* flags in task_struct,
we can reuse the current->journal_info to do that, per Willy. As the
check of transaction reservation recursion is used by XFS only, we can
move the check into xfs_vm_writepage(s), per Dave.
Patch #1 and #2 are to use the memalloc_nofs_{save,restore} API,
which is introduced in
commit 7dea19f9ee63 ("mm: introduce memalloc_nofs_{save,restore} API"),
instead of using PF_MEMALLOC_NOFS directly in XFS.
Patch #1 is picked form Willy's patchset "Overhaul memalloc_no*"[1]
Patch #3 is the refactor of xfs_trans context, which is activated when
xfs_trans is allocated and deactivated when xfs_trans is freed.
Patch #4 is the implementation of reussing current->journal_info to
avoid transaction reservation recursion.
No obvious error occurred after running xfstests.
[1]. https://lore.kernel.org/linux-mm/20200625113122.7540-1-willy@xxxxxxxxxxxxx
v10:
- refactor the code, per Dave.
v9:
- rebase it on xfs tree.
- Darrick fixed an error occurred in xfs/141
- run xfstests, and no obvious error occurred.
v8:
- check xfs_trans_context_active() in xfs_vm_writepage(s), per Dave.
v7:
- check fstrans recursion for XFS only, by introducing a new member in
struct writeback_control.
v6:
- add Michal's ack and comment in patch #1.
v5:
- pick one of Willy's patch
- introduce four new helpers, per Dave
v4:
- retitle from "xfs: introduce task->in_fstrans for transaction reservation
recursion protection"
- reuse current->journal_info, per Willy
Matthew Wilcox (Oracle) (1):
mm: Add become_kswapd and restore_kswapd
Yafang Shao (3):
xfs: use memalloc_nofs_{save,restore} in xfs transaction
xfs: refactor the usage around xfs_trans_context_{set,clear}
xfs: use current->journal_info to avoid transaction reservation
recursion
fs/iomap/buffered-io.c | 7 -------
fs/xfs/libxfs/xfs_btree.c | 14 ++++++++------
fs/xfs/xfs_aops.c | 21 +++++++++++++++++++--
fs/xfs/xfs_linux.h | 4 ----
fs/xfs/xfs_trans.c | 24 +++++++++++-------------
fs/xfs/xfs_trans.h | 37 +++++++++++++++++++++++++++++++++++++
include/linux/sched/mm.h | 23 +++++++++++++++++++++++
mm/vmscan.c | 16 +---------------
8 files changed, 99 insertions(+), 47 deletions(-)
--
2.18.4
