[PATCH 09/16] fs: exit early in generic_update_time when there is no work

[Christoph Hellwig]

Exit early if not attributes are to be updated, to avoid a spurious call
to __mark_inode_dirty which can turn into a fairly expensive no-op due to
the extra checks and locking.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 fs/inode.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/inode.c b/fs/inode.c
index 15a8b2cf78ef..cda78f76e1dd 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2110,6 +2110,9 @@ int generic_update_time(struct inode *inode, int flags)
 	int updated = inode_update_timestamps(inode, flags);
 	int dirty_flags = 0;
 
+	if (!updated)
+		return 0;
+
 	if (updated & (S_ATIME|S_MTIME|S_CTIME))
 		dirty_flags = inode->i_sb->s_flags & SB_LAZYTIME ? I_DIRTY_TIME : I_DIRTY_SYNC;
 	if (updated & S_VERSION)
-- 
2.47.3