Btrfs: Make sure to cow the root during a snapshot

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

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 7e4cf62ada5ad324105f240de94e99d41e3a9025..504d37dfa6c90a1ae9084f11adfb3447e926235c 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2096,6 +2096,7 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
        struct btrfs_trans_handle *trans;
        struct btrfs_key key;
        struct btrfs_root_item new_root_item;
+       struct buffer_head *tmp;
        int ret;
        int err;
        u64 objectid;
@@ -2123,6 +2124,7 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
        key.offset = 1;
        key.flags = 0;
        btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+       btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
        btrfs_set_root_blocknr(&new_root_item, bh_blocknr(root->node));
 
        ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,