Commit fbf48bb0 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: track qgroup released data in own variable in insert_prealloc_file_extent 



There is a piece of weird code in insert_prealloc_file_extent(), which
looks like:

	ret = btrfs_qgroup_release_data(inode, file_offset, len);
	if (ret < 0)
		return ERR_PTR(ret);
	if (trans) {
		ret = insert_reserved_file_extent(trans, inode,
						  file_offset, &stack_fi,
						  true, ret);
	...
	}
	extent_info.is_new_extent = true;
	extent_info.qgroup_reserved = ret;
	...

Note how the variable @ret is abused here, and if anyone is adding code
just after btrfs_qgroup_release_data() call, it's super easy to
overwrite the @ret and cause tons of qgroup related bugs.

Fix such abuse by introducing new variable @qgroup_released, so that we
won't reuse the existing variable @ret.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent d2dcc8ed

fs/btrfs/inode.c

+6 −5
Original line number Diff line number Diff line
@@ -9873,6 +9873,7 @@ static struct btrfs_trans_handle *insert_prealloc_file_extent( 
	struct btrfs_path *path;

	u64 start = ins->objectid;

	u64 len = ins->offset;

	int qgroup_released;

	int ret;



	memset(&stack_fi, 0, sizeof(stack_fi));
@@ -9885,14 +9886,14 @@ static struct btrfs_trans_handle *insert_prealloc_file_extent( 
	btrfs_set_stack_file_extent_compression(&stack_fi, BTRFS_COMPRESS_NONE);

	/* Encryption and other encoding is reserved and all 0 */



	ret = btrfs_qgroup_release_data(inode, file_offset, len);

	if (ret < 0)

		return ERR_PTR(ret);

	qgroup_released = btrfs_qgroup_release_data(inode, file_offset, len);

	if (qgroup_released < 0)

		return ERR_PTR(qgroup_released);



	if (trans) {

		ret = insert_reserved_file_extent(trans, inode,

						  file_offset, &stack_fi,

						  true, ret);

						  true, qgroup_released);

		if (ret)

			return ERR_PTR(ret);

		return trans;
@@ -9905,7 +9906,7 @@ static struct btrfs_trans_handle *insert_prealloc_file_extent( 
	extent_info.file_offset = file_offset;

	extent_info.extent_buf = (char *)&stack_fi;

	extent_info.is_new_extent = true;

	extent_info.qgroup_reserved = ret;

	extent_info.qgroup_reserved = qgroup_released;

	extent_info.insertions = 0;



	path = btrfs_alloc_path();