get rid of kern_path_parent()

all callers want the same thing, actually - a kinda-sorta analog of
kern_path_create().  I.e. they want parent vfsmount/dentry (with
->i_mutex held, to make sure the child dentry is still their child)
+ the child dentry.

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

1 files changed, 20 insertions, 2 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 5abab9176903..6b29a51bef5d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1814,9 +1814,27 @@ static int do_path_lookup(int dfd, const char *name,
         return retval;
 }
 
-int kern_path_parent(const char *name, struct nameidata *nd)
+/* does lookup, returns the object with parent locked */
+struct dentry *kern_path_locked(const char *name, struct path *path)
 {
-        return do_path_lookup(AT_FDCWD, name, LOOKUP_PARENT, nd);
+        struct nameidata nd;
+        struct dentry *d;
+        int err = do_path_lookup(AT_FDCWD, name, LOOKUP_PARENT, &nd);
+        if (err)
+                return ERR_PTR(err);
+        if (nd.last_type != LAST_NORM) {
+                path_put(&nd.path);
+                return ERR_PTR(-EINVAL);
+        }
+        mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
+        d = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len);
+        if (IS_ERR(d)) {
+                mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
+                path_put(&nd.path);
+                return d;
+        }
+        *path = nd.path;
+        return d;
 }
 
 int kern_path(const char *name, unsigned int flags, struct path *path)