Btrfs: Some code cleanups

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

fs/btrfs/ctree.c

@@ -172,11 +172,13 @@ static int check_node(struct btrfs_root *root, struct btrfs_path *path,
 
 	if (path->nodes[level + 1])
 		parent = btrfs_buffer_node(path->nodes[level + 1]);
-	parent_slot = path->slots[level + 1];
+
 	slot = path->slots[level];
 	BUG_ON(nritems == 0);
 	if (parent) {
 		struct btrfs_disk_key *parent_key;
+
+		parent_slot = path->slots[level + 1];
 		parent_key = &parent->ptrs[parent_slot].key;
 		BUG_ON(memcmp(parent_key, &node->ptrs[0].key,
 			      sizeof(struct btrfs_disk_key)));
@@ -208,7 +210,7 @@ static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
 
 	if (path->nodes[level + 1])
 		parent = btrfs_buffer_node(path->nodes[level + 1]);
-	parent_slot = path->slots[level + 1];
+
 	BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
 
 	if (nritems == 0)
@@ -216,6 +218,8 @@ static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
 
 	if (parent) {
 		struct btrfs_disk_key *parent_key;
+
+		parent_slot = path->slots[level + 1];
 		parent_key = &parent->ptrs[parent_slot].key;
 		BUG_ON(memcmp(parent_key, &leaf->items[0].key,
 		       sizeof(struct btrfs_disk_key)));

fs/btrfs/root-tree.c

@@ -135,8 +135,8 @@ int btrfs_find_dead_roots(struct btrfs_root *root)
 		if (btrfs_root_refs(ri) != 0)
 			goto next;
 		dead_root = btrfs_read_fs_root_no_radix(root->fs_info, &key);
-		if (IS_ERR(root)) {
-			ret = PTR_ERR(root);
+		if (IS_ERR(dead_root)) {
+			ret = PTR_ERR(dead_root);
 			goto err;
 		}
 		ret = btrfs_add_dead_root(dead_root,