Document ->tmpfile()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 7d9ca7a..e95d313 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -64,6 +64,7 @@
 	int (*atomic_open)(struct inode *, struct dentry *,
 				struct file *, unsigned open_flag,
 				umode_t create_mode, int *opened);
+	int (*tmpfile) (struct inode *, struct dentry *, umode_t);
 
 locking rules:
 	all may block
@@ -91,6 +92,7 @@
 fiemap:		no
 update_time:	no
 atomic_open:	yes
+tmpfile:	no
 
 	Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
 victim.