1// SPDX-License-Identifier: GPL-2.0
2/*
3 * QNX4 file system, Linux implementation.
4 *
5 * Version : 0.2.1
6 *
7 * Using parts of the xiafs filesystem.
8 *
9 * History :
10 *
11 * 28-05-1998 by Richard Frowijn : first release.
12 * 20-06-1998 by Frank Denis : basic optimisations.
13 * 25-06-1998 by Frank Denis : qnx4_is_free, qnx4_set_bitmap, qnx4_bmap .
14 * 28-06-1998 by Frank Denis : qnx4_free_inode (to be fixed) .
15 */
16
17#include <linux/buffer_head.h>
18#include <linux/bitops.h>
19#include "qnx4.h"
20
21unsigned long qnx4_count_free_blocks(struct super_block *sb)
22{
23	int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
24	int total = 0;
25	int total_free = 0;
26	int offset = 0;
27	int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
28	struct buffer_head *bh;
29
30	while (total < size) {
31		int bytes = min(size - total, QNX4_BLOCK_SIZE);
32
33		if ((bh = sb_bread(sb, start + offset)) == NULL) {
34			printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
35			break;
36		}
37		total_free += bytes * BITS_PER_BYTE -
38				memweight(bh->b_data, bytes);
39		brelse(bh);
40		total += bytes;
41		offset++;
42	}
43
44	return total_free;
45}
46