Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a05346de authored by Xiyu Yang's avatar Xiyu Yang Committed by Greg Kroah-Hartman
Browse files

btrfs: fix block group leak when removing fails 



commit f6033c5e333238f299c3ae03fac8cc1365b23b77 upstream.

btrfs_remove_block_group() invokes btrfs_lookup_block_group(), which
returns a local reference of the block group that contains the given
bytenr to "block_group" with increased refcount.

When btrfs_remove_block_group() returns, "block_group" becomes invalid,
so the refcount should be decreased to keep refcount balanced.

The reference counting issue happens in several exception handling paths
of btrfs_remove_block_group(). When those error scenarios occur such as
btrfs_alloc_path() returns NULL, the function forgets to decrease its
refcnt increased by btrfs_lookup_block_group() and will cause a refcnt
leak.

Fix this issue by jumping to "out_put_group" label and calling
btrfs_put_block_group() when those error scenarios occur.

CC: stable@vger.kernel.org # 4.4+
Signed-off-by: default avatarXiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: default avatarXin Tan <tanxin.ctf@gmail.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9148b1aa

fs/btrfs/extent-tree.c

+10 −6
Original line number Diff line number Diff line
@@ -10645,7 +10645,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, 
	path = btrfs_alloc_path();

	if (!path) {

		ret = -ENOMEM;

		goto out;

		goto out_put_group;

	}



	/*
@@ -10684,7 +10684,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, 
		ret = btrfs_orphan_add(trans, inode);

		if (ret) {

			btrfs_add_delayed_iput(inode);

			goto out;

			goto out_put_group;

		}

		clear_nlink(inode);

		/* One for the block groups ref */
@@ -10707,13 +10707,13 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, 


	ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);

	if (ret < 0)

		goto out;

		goto out_put_group;

	if (ret > 0)

		btrfs_release_path(path);

	if (ret == 0) {

		ret = btrfs_del_item(trans, tree_root, path);

		if (ret)

			goto out;

			goto out_put_group;

		btrfs_release_path(path);

	}
@@ -10871,9 +10871,9 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, 


	ret = remove_block_group_free_space(trans, root->fs_info, block_group);

	if (ret)

		goto out;

		goto out_put_group;



	btrfs_put_block_group(block_group);

	/* Once for the block groups rbtree */

	btrfs_put_block_group(block_group);



	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
@@ -10883,6 +10883,10 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, 
		goto out;



	ret = btrfs_del_item(trans, root, path);



out_put_group:

	/* Once for the lookup reference */

	btrfs_put_block_group(block_group);

out:

	btrfs_free_path(path);

	return ret;