Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs pile 3 (of many) from Al Viro:
 "Waiman's conversion of d_path() and bits related to it,
  kern_path_mountpoint(), several cleanups and fixes (exportfs
  one is -stable fodder, IMO).

  There definitely will be more...  ;-/"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  split read_seqretry_or_unlock(), convert d_walk() to resulting primitives
  dcache: Translating dentry into pathname without taking rename_lock
  autofs4 - fix device ioctl mount lookup
  introduce kern_path_mountpoint()
  rename user_path_umountat() to user_path_mountpoint_at()
  take unlazy_walk() into umount_lookup_last()
  Kill indirect include of file.h from eventfd.h, use fdget() in cgroup.c
  prune_super(): sb->s_op is never NULL
  exportfs: don't assume that ->iterate() won't feed us too long entries
  afs: get rid of redundant ->d_name.len checks

1 files changed, 12 insertions, 11 deletions

diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index 743c7c2c949d..0f00da329e71 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -183,13 +183,14 @@ static int autofs_dev_ioctl_protosubver(struct file *fp,
 	return 0;
 }
 
+/* Find the topmost mount satisfying test() */
 static int find_autofs_mount(const char *pathname,
 			     struct path *res,
 			     int test(struct path *path, void *data),
 			     void *data)
 {
 	struct path path;
-	int err = kern_path(pathname, 0, &path);
+	int err = kern_path_mountpoint(AT_FDCWD, pathname, &path, 0);
 	if (err)
 		return err;
 	err = -ENOENT;
@@ -197,10 +198,9 @@ static int find_autofs_mount(const char *pathname,
 		if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
 			if (test(&path, data)) {
 				path_get(&path);
-				if (!err) /* already found some */
-					path_put(res);
 				*res = path;
 				err = 0;
+				break;
 			}
 		}
 		if (!follow_up(&path))
@@ -486,12 +486,11 @@ static int autofs_dev_ioctl_askumount(struct file *fp,
  * mount if there is one or 0 if it isn't a mountpoint.
  *
  * If we aren't supplied with a file descriptor then we
- * lookup the nameidata of the path and check if it is the
- * root of a mount. If a type is given we are looking for
- * a particular autofs mount and if we don't find a match
- * we return fail. If the located nameidata path is the
- * root of a mount we return 1 along with the super magic
- * of the mount or 0 otherwise.
+ * lookup the path and check if it is the root of a mount.
+ * If a type is given we are looking for a particular autofs
+ * mount and if we don't find a match we return fail. If the
+ * located path is the root of a mount we return 1 along with
+ * the super magic of the mount or 0 otherwise.
  *
  * In both cases the the device number (as returned by
  * new_encode_dev()) is also returned.
@@ -519,9 +518,11 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp,
 
 	if (!fp || param->ioctlfd == -1) {
 		if (autofs_type_any(type))
-			err = kern_path(name, LOOKUP_FOLLOW, &path);
+			err = kern_path_mountpoint(AT_FDCWD,
+						   name, &path, LOOKUP_FOLLOW);
 		else
-			err = find_autofs_mount(name, &path, test_by_type, &type);
+			err = find_autofs_mount(name, &path,
+						test_by_type, &type);
 		if (err)
 			goto out;
 		devid = new_encode_dev(path.dentry->d_sb->s_dev);