Add an AT_NO_AUTOMOUNT flag to suppress terminal automount

Add an AT_NO_AUTOMOUNT flag to suppress terminal automounting of automount
point directories.  This can be used by fstatat() users to permit the
gathering of attributes on an automount point and also prevent
mass-automounting of a directory of automount points by ls.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 8ef2c78..f276d4f 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -45,6 +45,7 @@
  *  - ending slashes ok even for nonexistent files
  *  - internal "there are more path components" flag
  *  - dentry cache is untrusted; force a real lookup
+ *  - suppress terminal automount
  */
 #define LOOKUP_FOLLOW		0x0001
 #define LOOKUP_DIRECTORY	0x0002
@@ -53,6 +54,7 @@
 #define LOOKUP_PARENT		0x0010
 #define LOOKUP_REVAL		0x0020
 #define LOOKUP_RCU		0x0040
+#define LOOKUP_NO_AUTOMOUNT	0x0080
 /*
  * Intent data
  */