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
20 #if 0
21 int qnx4_new_block(struct super_block *sb)
22 {
23 return 0;
24 }
25 #endif /* 0 */
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 }
81
82 #ifdef CONFIG_QNX4FS_RW
83
84 int qnx4_is_free(struct super_block *sb, long block)
85 {
86 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
87 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
88 struct buffer_head *bh;
89 const char *g;
90 int ret = -EIO;
91
92 start += block / (QNX4_BLOCK_SIZE * 8);
93 QNX4DEBUG(("qnx4: is_free requesting block [%lu], bitmap in block [%lu]\n",
94 (unsigned long) block, (unsigned long) start));
95 (void) size; /* CHECKME */
96 bh = sb_bread(sb, start);
97 if (bh == NULL) {
98 return -EIO;
99 }
100 g = bh->b_data + (block % QNX4_BLOCK_SIZE);
101 if (((*g) & (1 << (block % 8))) == 0) {
102 QNX4DEBUG(("qnx4: is_free -> block is free\n"));
103 ret = 1;
104 } else {
105 QNX4DEBUG(("qnx4: is_free -> block is busy\n"));
106 ret = 0;
107 }
108 brelse(bh);
109
110 return ret;
111 }
112
113 int qnx4_set_bitmap(struct super_block *sb, long block, int busy)
114 {
115 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
116 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
117 struct buffer_head *bh;
118 char *g;
119
120 start += block / (QNX4_BLOCK_SIZE * 8);
121 QNX4DEBUG(("qnx4: set_bitmap requesting block [%lu], bitmap in block [%lu]\n",
122 (unsigned long) block, (unsigned long) start));
123 (void) size; /* CHECKME */
124 bh = sb_bread(sb, start);
125 if (bh == NULL) {
126 return -EIO;
127 }
128 g = bh->b_data + (block % QNX4_BLOCK_SIZE);
129 if (busy == 0) {
130 (*g) &= ~(1 << (block % 8));
131 } else {
132 (*g) |= (1 << (block % 8));
133 }
134 mark_buffer_dirty(bh);
135 brelse(bh);
136
137 return 0;
138 }
139
140 static void qnx4_clear_inode(struct inode *inode)
141 {
142 struct qnx4_inode_entry *qnx4_ino = qnx4_raw_inode(inode);
143 /* What for? */
144 memset(qnx4_ino->di_fname, 0, sizeof qnx4_ino->di_fname);
145 qnx4_ino->di_size = 0;
146 qnx4_ino->di_num_xtnts = 0;
147 qnx4_ino->di_mode = 0;
148 qnx4_ino->di_status = 0;
149 }
150
151 void qnx4_free_inode(struct inode *inode)
152 {
153 if (inode->i_ino < 1) {
154 printk("free_inode: inode 0 or nonexistent inode\n");
155 return;
156 }
157 qnx4_clear_inode(inode);
158 clear_inode(inode);
159 }
160
161 #endif
162
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