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| author | David Howells <dhowells@redhat.com> | 2012-06-25 12:55:28 +0100 |
|---|---|---|
| committer | Ziyan <jaraidaniel@gmail.com> | 2016-04-03 14:55:51 +0200 |
| commit | bc9600bb91c52252e67c163606ca57fbf0c369b3 (patch) | |
| tree | 3ccdbef9f842f9adb1f06aea8498db894172a2a3 | |
| parent | 14df004d01cf1e919471fdf32cf97e7a7169178b (diff) | |
| download | kernel_samsung_tuna-bc9600bb91c52252e67c163606ca57fbf0c369b3.zip kernel_samsung_tuna-bc9600bb91c52252e67c163606ca57fbf0c369b3.tar.gz kernel_samsung_tuna-bc9600bb91c52252e67c163606ca57fbf0c369b3.tar.bz2 | |
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>
(cherry picked from commit f015f1267b23d3530d3f874243fb83cb5f443005)
| -rw-r--r-- | fs/namei.c | 10 | ||||
| -rw-r--r-- | fs/namespace.c | 16 |
2 files changed, 24 insertions, 2 deletions
@@ -740,6 +740,16 @@ 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 vfsmount *parent; diff --git a/fs/namespace.c b/fs/namespace.c index 040e00f..7df8bf9 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -509,8 +509,20 @@ struct vfsmount *__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) { |