Merge tag 'pull-automount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull automount updates from Al Viro:
 "Automount wart removal

  A bunch of odd boilerplate gone from instances - the reason for
  those was the need to protect the yet-to-be-attched mount from
  mark_mounts_for_expiry() deciding to take it out.

  But that's easy to detect and take care of in mark_mounts_for_expiry()
  itself; no need to have every instance simulate mount being busy by
  grabbing an extra reference to it, with finish_automount() undoing
  that once it attaches that mount.

  Should've done it that way from the very beginning... This is a
  flagday change, thankfully there are very few instances.

  vfs_submount() is gone - its sole remaining user (trace_automount)
  had been switched to saner primitives"

* tag 'pull-automount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  kill vfs_submount()
  saner calling conventions for ->d_automount()

1 files changed, 3 insertions, 21 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 7c0ebc4f4ef2..2f2e93927f46 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1326,21 +1326,6 @@ struct vfsmount *vfs_kern_mount(struct file_system_type *type,
 }
 EXPORT_SYMBOL_GPL(vfs_kern_mount);
 
-struct vfsmount *
-vfs_submount(const struct dentry *mountpoint, struct file_system_type *type,
-	     const char *name, void *data)
-{
-	/* Until it is worked out how to pass the user namespace
-	 * through from the parent mount to the submount don't support
-	 * unprivileged mounts with submounts.
-	 */
-	if (mountpoint->d_sb->s_user_ns != &init_user_ns)
-		return ERR_PTR(-EPERM);
-
-	return vfs_kern_mount(type, SB_SUBMOUNT, name, data);
-}
-EXPORT_SYMBOL_GPL(vfs_submount);
-
 static struct mount *clone_mnt(struct mount *old, struct dentry *root,
 					int flag)
 {
@@ -3889,10 +3874,6 @@ int finish_automount(struct vfsmount *m, const struct path *path)
 		return PTR_ERR(m);
 
 	mnt = real_mount(m);
-	/* The new mount record should have at least 2 refs to prevent it being
-	 * expired before we get a chance to add it
-	 */
-	BUG_ON(mnt_get_count(mnt) < 2);
 
 	if (m->mnt_sb == path->mnt->mnt_sb &&
 	    m->mnt_root == dentry) {
@@ -3925,7 +3906,6 @@ int finish_automount(struct vfsmount *m, const struct path *path)
 	unlock_mount(mp);
 	if (unlikely(err))
 		goto discard;
-	mntput(m);
 	return 0;
 
 discard_locked:
@@ -3939,7 +3919,6 @@ discard:
 		namespace_unlock();
 	}
 	mntput(m);
-	mntput(m);
 	return err;
 }
 
@@ -3976,11 +3955,14 @@ void mark_mounts_for_expiry(struct list_head *mounts)
 
 	/* extract from the expiration list every vfsmount that matches the
 	 * following criteria:
+	 * - already mounted
 	 * - only referenced by its parent vfsmount
 	 * - still marked for expiry (marked on the last call here; marks are
 	 *   cleared by mntput())
 	 */
 	list_for_each_entry_safe(mnt, next, mounts, mnt_expire) {
+		if (!is_mounted(&mnt->mnt))
+			continue;
 		if (!xchg(&mnt->mnt_expiry_mark, 1) ||
 			propagate_mount_busy(mnt, 1))
 			continue;