[PATCH v3 18/19] btrfs: only dirty the inode in btrfs_update_time if something was changed

[Jeff Layton]

From: Jeff Layton <jlayton@xxxxxxxxxx>

At this point, we know that "now" and the file times may differ, and we
suspect that the i_version has been flagged to be bumped. Attempt to
bump the i_version, and only mark the inode dirty if that actually
occurred or if one of the times was updated.

Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
 fs/btrfs/inode.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ac8692849a81..76245323a7c8 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6107,19 +6107,20 @@ static int btrfs_update_time(struct inode *inode, struct timespec *now,
 			     int flags)
 {
 	struct btrfs_root *root = BTRFS_I(inode)->root;
+	bool dirty = flags & ~S_VERSION;
 
 	if (btrfs_root_readonly(root))
 		return -EROFS;
 
 	if (flags & S_VERSION)
-		inode_inc_iversion(inode);
+		dirty |= inode_maybe_inc_iversion(inode, dirty);
 	if (flags & S_CTIME)
 		inode->i_ctime = *now;
 	if (flags & S_MTIME)
 		inode->i_mtime = *now;
 	if (flags & S_ATIME)
 		inode->i_atime = *now;
-	return btrfs_dirty_inode(inode);
+	return dirty ? btrfs_dirty_inode(inode) : 0;
 }
 
 /*
-- 
2.14.3