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Dave Kleikampac27a0e2006-10-11 01:20:50 -07001/*
Mingming Cao617ba132006-10-11 01:20:53 -07002 * linux/fs/ext4/bitmap.c
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 */
9
10#include <linux/buffer_head.h>
Mingming Caodab291a2006-10-11 01:21:01 -070011#include <linux/jbd2.h>
Christoph Hellwig3dcf5452008-04-29 18:13:32 -040012#include "ext4.h"
Dave Kleikampac27a0e2006-10-11 01:20:50 -070013
Mingming Cao617ba132006-10-11 01:20:53 -070014#ifdef EXT4FS_DEBUG
Dave Kleikampac27a0e2006-10-11 01:20:50 -070015
Philippe De Muyterfebfcf92007-10-16 23:26:15 -070016static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
Dave Kleikampac27a0e2006-10-11 01:20:50 -070017
Theodore Ts'oaf5bc922008-09-08 22:25:24 -040018unsigned long ext4_count_free(struct buffer_head *map, unsigned int numchars)
Dave Kleikampac27a0e2006-10-11 01:20:50 -070019{
20 unsigned int i;
21 unsigned long sum = 0;
22
23 if (!map)
Theodore Ts'oaf5bc922008-09-08 22:25:24 -040024 return 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -070025 for (i = 0; i < numchars; i++)
26 sum += nibblemap[map->b_data[i] & 0xf] +
27 nibblemap[(map->b_data[i] >> 4) & 0xf];
Theodore Ts'oaf5bc922008-09-08 22:25:24 -040028 return sum;
Dave Kleikampac27a0e2006-10-11 01:20:50 -070029}
30
Mingming Cao617ba132006-10-11 01:20:53 -070031#endif /* EXT4FS_DEBUG */
Dave Kleikampac27a0e2006-10-11 01:20:50 -070032