VFS: Comment mount following code

Add comments describing what the directions "up" and "down" mean and ref count
handling to the VFS mount following family of functions.

Signed-off-by: Valerie Aurora <vaurora@redhat.com> (Original author)
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 0e1b9c3eb36d..c6dcb4c8f86c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -672,6 +672,16 @@ static int follow_up_rcu(struct path *path)
         return 1;
 }
 
+/*
+ * follow_up - Find the mountpoint of path's vfsmount
+ *
+ * Given a path, find the mountpoint of its source file system.
+ * Replace @path with the path of the mountpoint in the parent mount.
+ * Up is towards /.
+ *
+ * Return 1 if we went up a level and 0 if we were already at the
+ * root.
+ */
 int follow_up(struct path *path)
 {
         struct mount *mnt = real_mount(path->mnt);