btrfs: fix the length of reserved qgroup to free

commit 2b084d8205949dd804e279df8e68531da78be1e8 upstream.

The dealloc flag may be cleared and the extent won't reach the disk in
cow_file_range when errors path. The reserved qgroup space is freed in
commit 30479f31d44d ("btrfs: fix qgroup reserve leaks in
cow_file_range"). However, the length of untouched region to free needs
to be adjusted with the correct remaining region size.

Fixes: 30479f31d44d ("btrfs: fix qgroup reserve leaks in cow_file_range")
CC: [email protected] # 6.11+
Reviewed-by: Qu Wenruo <[email protected]>
Reviewed-by: Boris Burkov <[email protected]>
Signed-off-by: Haisu Wang <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Haisu Wang

fs/btrfs/inode.c

@@ -1442,7 +1442,7 @@ static noinline int cow_file_range(struct btrfs_inode *inode,
 		clear_bits |= EXTENT_CLEAR_DATA_RESV;
 		extent_clear_unlock_delalloc(inode, start, end, locked_page,
 					     clear_bits, page_ops);
-		btrfs_qgroup_free_data(inode, NULL, start, cur_alloc_size, NULL);
+		btrfs_qgroup_free_data(inode, NULL, start, end - start + 1, NULL);
 	}
 	return ret;
 }