xfs: use current->journal_info for detecting transaction recursion

Because the iomap code using PF_MEMALLOC_NOFS to detect transaction
recursion in XFS is just wrong. Remove it from the iomap code and
replace it with XFS specific internal checks using
current->journal_info instead.

[djwong: This change also realigns the lifetime of NOFS flag changes to
match the incore transaction, instead of the inconsistent scheme we have
now.]

Fixes: 9070733b4efa ("xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 30 insertions, 0 deletions

diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 8b03fbfe9a1b..9dd745cf77c9 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -281,4 +281,34 @@ int xfs_trans_alloc_ichange(struct xfs_inode *ip, struct xfs_dquot *udqp,
 		struct xfs_dquot *gdqp, struct xfs_dquot *pdqp, bool force,
 		struct xfs_trans **tpp);
 
+static inline void
+xfs_trans_set_context(
+	struct xfs_trans	*tp)
+{
+	ASSERT(current->journal_info == NULL);
+	tp->t_pflags = memalloc_nofs_save();
+	current->journal_info = tp;
+}
+
+static inline void
+xfs_trans_clear_context(
+	struct xfs_trans	*tp)
+{
+	if (current->journal_info == tp) {
+		memalloc_nofs_restore(tp->t_pflags);
+		current->journal_info = NULL;
+	}
+}
+
+static inline void
+xfs_trans_switch_context(
+	struct xfs_trans	*old_tp,
+	struct xfs_trans	*new_tp)
+{
+	ASSERT(current->journal_info == old_tp);
+	new_tp->t_pflags = old_tp->t_pflags;
+	old_tp->t_pflags = 0;
+	current->journal_info = new_tp;
+}
+
 #endif	/* __XFS_TRANS_H__ */