[PATCH 11/11] xfs: enable non-blocking timestamp updates

[Christoph Hellwig]

The lazytime path using the generic helpers can never block in XFS
because there is no ->dirty_inode method that could block.  Allow
non-blocking timestamp updates for this case by replacing
generic_update_time with the open coded version without the S_NOWAIT
check.

Fixes: 66fa3cedf16a ("fs: Add async write file modification handling.")
Signed-off-by: Christoph Hellwig <hch at lst.de>
Reviewed-by: Jeff Layton <jlayton at kernel.org>
---
 fs/xfs/xfs_iops.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index e12c6e6d313e..1fba10281e54 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1195,16 +1195,23 @@ xfs_vn_update_time(
 
 	trace_xfs_update_time(ip);
 
-	if (flags & S_NOWAIT)
-		return -EAGAIN;
-
 	if (inode->i_sb->s_flags & SB_LAZYTIME) {
-		if (!((flags & S_VERSION) &&
-		      inode_maybe_inc_iversion(inode, false)))
-			return generic_update_time(inode, flags);
+		int dirty_flags;
+
+		error = inode_update_timestamps(inode,
+				flags | S_CAN_NOWAIT_LAZYTIME, &dirty_flags);
+		if (error)
+			return error;
+		if (dirty_flags == I_DIRTY_TIME) {
+			__mark_inode_dirty(inode, I_DIRTY_TIME);
+			return 0;
+		}
 
 		/* Capture the iversion update that just occurred */
 		log_flags |= XFS_ILOG_CORE;
+	} else {
+		if (flags & S_NOWAIT)
+			return -EAGAIN;
 	}
 
 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
-- 
2.47.3