diff options
| author | David Howells | 2012-06-25 12:55:28 +0100 |
|---|---|---|
| committer | Al Viro | 2012-07-14 16:38:32 +0400 |
| commit | f015f1267b23d3530d3f874243fb83cb5f443005 (patch) | |
| tree | 14db3794b2716614ee8acfaaad011d6fe7e6db44 /fs | |
| parent | be34d1a3bc4b6f357a49acb55ae870c81337e4f0 (diff) | |
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>
Diffstat (limited to 'fs')
| -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) { |