---

yaml
---
r: 274675
b: refs/heads/master
c: f9d9ef6
h: refs/heads/master
i:
  274673: 0580bef
  274671: d57bc77
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 20bcd64934e4eb8f3f90a0dca54fb0ac2edd7795
+refs/heads/master: f9d9ef62cd3ecbd6cbb7957a253c1e81f69d5586

trunk/fs/btrfs/super.c

@@ -740,6 +740,16 @@ static int btrfs_set_super(struct super_block *s, void *data)
 	return set_anon_super(s, data);
 }
 
+/*
+ * subvolumes are identified by ino 256
+ */
+static inline int is_subvolume_inode(struct inode *inode)
+{
+	if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
+		return 1;
+	return 0;
+}
+
 /*
  * This will strip out the subvol=%s argument for an argument string and add
  * subvolid=0 to make sure we get the actual tree root for path walking to the
@@ -843,6 +853,15 @@ static struct dentry *mount_subvol(const char *subvol_name, int flags,
 	if (error)
 		return ERR_PTR(error);
 
+	if (!is_subvolume_inode(path.dentry->d_inode)) {
+		path_put(&path);
+		mntput(mnt);
+		error = -EINVAL;
+		printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
+				subvol_name);
+		return ERR_PTR(-EINVAL);
+	}
+
 	/* Get a ref to the sb and the dentry we found and return it */
 	s = path.mnt->mnt_sb;
 	atomic_inc(&s->s_active);