vfs: more mnt_parent cleanups

a) mount --move is checking that ->mnt_parent is non-NULL before
looking if that parent happens to be shared; ->mnt_parent is never
NULL and it's not even an misspelled !mnt_has_parent()

b) pivot_root open-codes is_path_reachable(), poorly.

c) so does path_is_under(), while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 0 insertions, 15 deletions

diff --git a/fs/pnode.c b/fs/pnode.c
index f1cd958..4d5a06e 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -28,21 +28,6 @@ static inline struct vfsmount *next_slave(struct vfsmount *p)
 	return list_entry(p->mnt_slave.next, struct vfsmount, mnt_slave);
 }
 
-/*
- * Return true if path is reachable from root
- *
- * namespace_sem is held, and mnt is attached
- */
-static bool is_path_reachable(struct vfsmount *mnt, struct dentry *dentry,
-			 const struct path *root)
-{
-	while (mnt != root->mnt && mnt_has_parent(mnt)) {
-		dentry = mnt->mnt_mountpoint;
-		mnt = mnt->mnt_parent;
-	}
-	return mnt == root->mnt && is_subdir(dentry, root->dentry);
-}
-
 static struct vfsmount *get_peer_under_root(struct vfsmount *mnt,
 					    struct mnt_namespace *ns,
 					    const struct path *root)