locks: Set FL_CLOSE when removing flock locks on close()

Set FL_CLOSE in fl_flags as in locks_remove_posix() when clearing locks.
NFS will check for this flag to ensure an unlock is sent in a following
patch.

Fuse handles flock and posix locks differently for FL_CLOSE, and so
requires a fixup to retain the existing behavior for flock.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

include/linux/fs.h

@@ -909,6 +909,8 @@ static inline struct file *get_file(struct file *f)
 #define FL_OFDLCK	1024	/* lock is "owned" by struct file */
 #define FL_LAYOUT	2048	/* outstanding pNFS layout */
 
+#define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE)
+
 /*
  * Special return value from posix_lock_file() and vfs_lock_file() for
  * asynchronous locking.