From 3a8c7231d53641a21d794c7406044e19ad299a00 Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@redhat.com>
Date: Mon, 11 Dec 2017 06:35:24 -0500
Subject: [PATCH 21/24] btrfs: only dirty the inode in btrfs_update_time if
 something was changed
Git-commit: 3a8c7231d53641a21d794c7406044e19ad299a00
Patch-mainline: v4.16-rc1
References: bsc#1081186

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@redhat.com>
Acked-by: David Sterba <dsterba@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Acked-by: Jan Kara <jack@suse.cz>

---
 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 aee5b0c28a4f..d46b7a26af5c 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6074,19 +6074,20 @@ 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;
 }
 
 /*
-- 
2.10.0