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, 25 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 8a75e3b0f49d..64c8ce4c147f 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2853,31 +2853,6 @@ int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
         return result;
 }
 
-int path_is_under(struct path *path1, struct path *path2)
-{
-        struct vfsmount *mnt = path1->mnt;
-        struct dentry *dentry = path1->dentry;
-        int res;
-
-        br_read_lock(vfsmount_lock);
-        if (mnt != path2->mnt) {
-                for (;;) {
-                        if (!mnt_has_parent(mnt)) {
-                                br_read_unlock(vfsmount_lock);
-                                return 0;
-                        }
-                        if (mnt->mnt_parent == path2->mnt)
-                                break;
-                        mnt = mnt->mnt_parent;
-                }
-                dentry = mnt->mnt_mountpoint;
-        }
-        res = is_subdir(dentry, path2->dentry);
-        br_read_unlock(vfsmount_lock);
-        return res;
-}
-EXPORT_SYMBOL(path_is_under);
-
 void d_genocide(struct dentry *root)
 {
         struct dentry *this_parent;