AFS: implement file locking

Implement file locking for AFS.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 51c938a..aa4530c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -820,6 +820,10 @@
 	union {
 		struct nfs_lock_info	nfs_fl;
 		struct nfs4_lock_info	nfs4_fl;
+		struct {
+			struct list_head link;	/* link in AFS vnode's pending_locks list */
+			int state;		/* state of grant or error if -ve */
+		} afs;
 	} fl_u;
 };