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Commit f015f126 authored by David Howells's avatar David Howells Committed by Al Viro
Browse files

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: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent be34d1a3

fs/namei.c

+10 −0
Original line number Diff line number Diff line
@@ -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);

fs/namespace.c

+14 −2
Original line number Diff line number Diff line
@@ -515,8 +515,20 @@ struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry, 
}



/*

 * lookup_mnt increments the ref count before returning

 * the vfsmount struct.

 * lookup_mnt - Return the first child mount mounted at path

 *

 * "First" means first mounted chronologically.  If you create the

 * following mounts:

 *

 * mount /dev/sda1 /mnt

 * mount /dev/sda2 /mnt

 * mount /dev/sda3 /mnt

 *

 * Then lookup_mnt() on the base /mnt dentry in the root mount will

 * return successively the root dentry and vfsmount of /dev/sda1, then

 * /dev/sda2, then /dev/sda3, then NULL.

 *

 * lookup_mnt takes a reference to the found vfsmount.

 */

struct vfsmount *lookup_mnt(struct path *path)

{