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
count_bits(register const char * bmPart,register int size,int * const tf)20 static void count_bits(register const char *bmPart, register int size,
21 int *const tf)
22 {
23 char b;
24 int tot = *tf;
25
26 if (size > QNX4_BLOCK_SIZE) {
27 size = QNX4_BLOCK_SIZE;
28 }
29 do {
30 b = *bmPart++;
31 tot += 8 - hweight8(b);
32 size--;
33 } while (size != 0);
34 *tf = tot;
35 }
36
qnx4_count_free_blocks(struct super_block * sb)37 unsigned long qnx4_count_free_blocks(struct super_block *sb)
38 {
39 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
40 int total = 0;
41 int total_free = 0;
42 int offset = 0;
43 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
44 struct buffer_head *bh;
45
46 while (total < size) {
47 if ((bh = sb_bread(sb, start + offset)) == NULL) {
48 printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
49 break;
50 }
51 count_bits(bh->b_data, size - total, &total_free);
52 brelse(bh);
53 total += QNX4_BLOCK_SIZE;
54 offset++;
55 }
56
57 return total_free;
58 }
59