diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index b85b6d7d0ccd5cf6dbf4fbe909264bb072f22eb8..1096398e1351f880a5529b401f508acdd8c127e5 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2019,10 +2019,19 @@ int btrfs_release_file(struct inode *inode, struct file *filp)
 static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
 {
 	int ret;
+	struct blk_plug plug;
 
+	/*
+	 * This is only called in fsync, which would do synchronous writes, so
+	 * a plug can merge adjacent IOs as much as possible.  Esp. in case of
+	 * multiple disks using raid profile, a large IO can be split to
+	 * several segments of stripe length (currently 64K).
+	 */
+	blk_start_plug(&plug);
 	atomic_inc(&BTRFS_I(inode)->sync_writers);
 	ret = btrfs_fdatawrite_range(inode, start, end);
 	atomic_dec(&BTRFS_I(inode)->sync_writers);
+	blk_finish_plug(&plug);
 
 	return ret;
 }