--- x/fs/btrfs/volumes.c
+++ y/fs/btrfs/volumes.c
@@ -1277,7 +1277,6 @@ int btrfs_open_devices(struct btrfs_fs_d
 	 * We also don't need the lock here as this is called during mount and
 	 * exclusion is provided by uuid_mutex
 	 */
-	mutex_lock(&uuid_mutex);
 	if (fs_devices->opened) {
 		fs_devices->opened++;
 		ret = 0;
@@ -1285,8 +1284,6 @@ int btrfs_open_devices(struct btrfs_fs_d
 		list_sort(NULL, &fs_devices->devices, devid_cmp);
 		ret = open_fs_devices(fs_devices, flags, holder);
 	}
-	mutex_unlock(&uuid_mutex);
-
 	return ret;
 }
 
--- x/fs/btrfs/super.c
+++ y/fs/btrfs/super.c
@@ -1472,22 +1472,6 @@ static struct dentry *btrfs_mount_root(s
 		goto error_fs_info;
 	}
 
-	mutex_lock(&uuid_mutex);
-	error = btrfs_parse_device_options(data);
-	if (error) {
-		mutex_unlock(&uuid_mutex);
-		goto error_fs_info;
-	}
-
-	device = btrfs_scan_one_device(device_name);
-	if (IS_ERR(device)) {
-		mutex_unlock(&uuid_mutex);
-		error = PTR_ERR(device);
-		goto error_fs_info;
-	}
-	fs_info->fs_devices = device->fs_devices;
-	mutex_unlock(&uuid_mutex);
-
 	s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
 		 fs_info);
 	if (IS_ERR(s)) {
@@ -1500,15 +1484,31 @@ static struct dentry *btrfs_mount_root(s
 		if ((flags ^ s->s_flags) & SB_RDONLY)
 			error = -EBUSY;
 	} else {
-		struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
+		struct btrfs_fs_devices *fs_devices;
+
+		mutex_lock(&uuid_mutex);
+		error = btrfs_parse_device_options(data);
+		if (error) {
+			mutex_unlock(&uuid_mutex);
+			goto error_fs_info;
+		}
 
+		device = btrfs_scan_one_device(device_name);
+		if (IS_ERR(device)) {
+			mutex_unlock(&uuid_mutex);
+			error = PTR_ERR(device);
+			goto error_fs_info;
+		}
+		fs_info->fs_devices = fs_devices = device->fs_devices;
 		error = btrfs_open_devices(fs_devices, sb_open_mode(flags), s);
+		mutex_unlock(&uuid_mutex);
+
 		if (error)
 			goto out_deactivate;
 
 		if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
 			error = -EACCES;
-			btrfs_close_devices(fs_info->fs_devices);
+			btrfs_close_devices(fs_devices);
 			goto out_deactivate;
 		}