[PATCH v13 2/4] xfs: use memalloc_nofs_{save,restore} in xfs transaction

Yafang Shao
2020-12-17T01:12:24Z

Introduce a new API to mark the start and end of XFS transactions.
For now, just save and restore the memalloc_nofs flags.

The new helpers as follows,
- xfs_trans_context_set
Mark the start of XFS transactions
- xfs_trans_context_clear
Mark the end of XFS transactions

Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Michal Hocko <mhocko@kernel.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
fs/xfs/xfs_aops.c | 4 ++--
fs/xfs/xfs_linux.h | 4 ----
fs/xfs/xfs_trans.c | 13 +++++++------
fs/xfs/xfs_trans.h | 12 ++++++++++++
4 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 4304c6416fbb..2371187b7615 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -62,7 +62,7 @@ xfs_setfilesize_trans_alloc(
* We hand off the transaction to the completion thread now, so
* clear the flag here.
*/
- current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
+ xfs_trans_context_clear(tp);
return 0;
}

@@ -125,7 +125,7 @@ xfs_setfilesize_ioend(
* thus we need to mark ourselves as being in a transaction manually.
* Similarly for freeze protection.
*/
- current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
+ xfs_trans_context_set(tp);
__sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS);

/* we abort the update if there was an IO error */
diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index 5b7a1e201559..6ab0f8043c73 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -102,10 +102,6 @@ typedef __u32 xfs_nlink_t;
#define xfs_cowb_secs xfs_params.cowb_timer.val

#define current_cpu() (raw_smp_processor_id())
-#define current_set_flags_nested(sp, f) \
- (*(sp) = current->flags, current->flags |= (f))
-#define current_restore_flags_nested(sp, f) \
- (current->flags = ((current->flags & ~(f)) | (*(sp) & (f))))

#define NBBY 8 /* number of bits per byte */

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index c94e71f741b6..11d390f0d3f2 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -154,7 +154,7 @@ xfs_trans_reserve(
bool rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;

/* Mark this thread as being in a transaction */
- current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
+ xfs_trans_context_set(tp);

/*
* Attempt to reserve the needed disk blocks by decrementing
@@ -164,7 +164,7 @@ xfs_trans_reserve(
if (blocks > 0) {
error = xfs_mod_fdblocks(mp, -((int64_t)blocks), rsvd);
if (error != 0) {
- current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
+ xfs_trans_context_clear(tp);
return -ENOSPC;
}
tp->t_blk_res += blocks;
@@ -241,7 +241,7 @@ xfs_trans_reserve(
tp->t_blk_res = 0;
}

- current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
+ xfs_trans_context_clear(tp);

return error;
}
@@ -878,7 +878,7 @@ __xfs_trans_commit(

xfs_log_commit_cil(mp, tp, &commit_lsn, regrant);

- current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
+ xfs_trans_context_clear(tp);
xfs_trans_free(tp);

/*
@@ -910,7 +910,8 @@ __xfs_trans_commit(
xfs_log_ticket_ungrant(mp->m_log, tp->t_ticket);
tp->t_ticket = NULL;
}
- current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
+
+ xfs_trans_context_clear(tp);
xfs_trans_free_items(tp, !!error);
xfs_trans_free(tp);

@@ -971,7 +972,7 @@ xfs_trans_cancel(
}

/* mark this thread as no longer being in a transaction */
- current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
+ xfs_trans_context_clear(tp);

xfs_trans_free_items(tp, dirty);
xfs_trans_free(tp);
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 084658946cc8..44b11c64a15e 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -268,4 +268,16 @@ xfs_trans_item_relog(
return lip->li_ops->iop_relog(lip, tp);
}

+static inline void
+xfs_trans_context_set(struct xfs_trans *tp)
+{
+ tp->t_pflags = memalloc_nofs_save();
+}
+
+static inline void
+xfs_trans_context_clear(struct xfs_trans *tp)
+{
+ memalloc_nofs_restore(tp->t_pflags);
+}
+
#endif /* __XFS_TRANS_H__ */
--
2.18.4