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1da177e4 LT |
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 | ||
1da177e4 LT |
16 | #include <linux/buffer_head.h> |
17 | #include <linux/bitops.h> | |
964f5369 | 18 | #include "qnx4.h" |
1da177e4 | 19 | |
7a1119b1 | 20 | #if 0 |
1da177e4 LT |
21 | int qnx4_new_block(struct super_block *sb) |
22 | { | |
23 | return 0; | |
24 | } | |
7a1119b1 | 25 | #endif /* 0 */ |
1da177e4 LT |
26 | |
27 | static void count_bits(register const char *bmPart, register int size, | |
28 | int *const tf) | |
29 | { | |
30 | char b; | |
31 | int tot = *tf; | |
32 | ||
33 | if (size > QNX4_BLOCK_SIZE) { | |
34 | size = QNX4_BLOCK_SIZE; | |
35 | } | |
36 | do { | |
37 | b = *bmPart++; | |
38 | if ((b & 1) == 0) | |
39 | tot++; | |
40 | if ((b & 2) == 0) | |
41 | tot++; | |
42 | if ((b & 4) == 0) | |
43 | tot++; | |
44 | if ((b & 8) == 0) | |
45 | tot++; | |
46 | if ((b & 16) == 0) | |
47 | tot++; | |
48 | if ((b & 32) == 0) | |
49 | tot++; | |
50 | if ((b & 64) == 0) | |
51 | tot++; | |
52 | if ((b & 128) == 0) | |
53 | tot++; | |
54 | size--; | |
55 | } while (size != 0); | |
56 | *tf = tot; | |
57 | } | |
58 | ||
59 | unsigned long qnx4_count_free_blocks(struct super_block *sb) | |
60 | { | |
61 | int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1; | |
62 | int total = 0; | |
63 | int total_free = 0; | |
64 | int offset = 0; | |
65 | int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size); | |
66 | struct buffer_head *bh; | |
67 | ||
68 | while (total < size) { | |
69 | if ((bh = sb_bread(sb, start + offset)) == NULL) { | |
70 | printk("qnx4: I/O error in counting free blocks\n"); | |
71 | break; | |
72 | } | |
73 | count_bits(bh->b_data, size - total, &total_free); | |
74 | brelse(bh); | |
75 | total += QNX4_BLOCK_SIZE; | |
76 | offset++; | |
77 | } | |
78 | ||
79 | return total_free; | |
80 | } |