1/*
2 * QNX4 file system, Linux implementation.
3 *
4 * Version : 0.2.1
5 *
6 * Using parts of the xiafs filesystem.
7 *
8 * History :
9 *
10 * 28-05-1998 by Richard Frowijn : first release.
11 * 20-06-1998 by Frank Denis : basic optimisations.
12 * 25-06-1998 by Frank Denis : qnx4_is_free, qnx4_set_bitmap, qnx4_bmap .
13 * 28-06-1998 by Frank Denis : qnx4_free_inode (to be fixed) .
14 */
15
16#include <linux/buffer_head.h>
17#include <linux/bitops.h>
18#include "qnx4.h"
19
20unsigned long qnx4_count_free_blocks(struct super_block *sb)
21{
22	int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
23	int total = 0;
24	int total_free = 0;
25	int offset = 0;
26	int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
27	struct buffer_head *bh;
28
29	while (total < size) {
30		int bytes = min(size - total, QNX4_BLOCK_SIZE);
31
32		if ((bh = sb_bread(sb, start + offset)) == NULL) {
33			printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
34			break;
35		}
36		total_free += bytes * BITS_PER_BYTE -
37				memweight(bh->b_data, bytes);
38		brelse(bh);
39		total += bytes;
40		offset++;
41	}
42
43	return total_free;
44}
45