diff options
| -rw-r--r-- | fs/namei.c | 10 | ||||
| -rw-r--r-- | fs/namespace.c | 16 |
2 files changed, 24 insertions, 2 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); diff --git a/fs/namespace.c b/fs/namespace.c index be1b07a774f1..c53d3381b0d0 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -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) { |