Btrfs: Fix buffer get/release issue in create_snapshot

btrfs_cow_block expects a reference to be held on the buffer being cow'd.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 37f8e0321af8..d0af0807d9f8 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2034,11 +2034,11 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
         key.objectid = objectid;
         key.offset = 1;
         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
-
+        extent_buffer_get(root->node);
         btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
+        free_extent_buffer(tmp);
         btrfs_set_root_bytenr(&new_root_item, root->node->start);
         btrfs_set_root_level(&new_root_item, btrfs_header_level(root->node));
-
         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
                                 &new_root_item);
         if (ret)