btrfs: fix reservation leak in some error paths when inserting inline extent

If we fail to allocate a path or join a transaction, we return from
__cow_file_range_inline() without freeing the reserved qgroup data,
resulting in a leak. Fix this by ensuring we call btrfs_qgroup_free_data()
in such cases.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: fdmanana

fs/btrfs/inode.c

@@ -617,19 +617,22 @@ static noinline int __cow_file_range_inline(struct btrfs_inode *inode,
 	struct btrfs_drop_extents_args drop_args = { 0 };
 	struct btrfs_root *root = inode->root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
-	struct btrfs_trans_handle *trans;
+	struct btrfs_trans_handle *trans = NULL;
 	u64 data_len = (compressed_size ?: size);
 	int ret;
 	struct btrfs_path *path;
 
 	path = btrfs_alloc_path();
-	if (!path)
-		return -ENOMEM;
+	if (!path) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
 	trans = btrfs_join_transaction(root);
 	if (IS_ERR(trans)) {
-		btrfs_free_path(path);
-		return PTR_ERR(trans);
+		ret = PTR_ERR(trans);
+		trans = NULL;
+		goto out;
 	}
 	trans->block_rsv = &inode->block_rsv;
 
@@ -680,7 +683,8 @@ static noinline int __cow_file_range_inline(struct btrfs_inode *inode,
 	if (ret <= 0)
 		btrfs_qgroup_free_data(inode, NULL, 0, fs_info->sectorsize, NULL);
 	btrfs_free_path(path);
-	btrfs_end_transaction(trans);
+	if (trans)
+		btrfs_end_transaction(trans);
 	return ret;
 }