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/time.h>
17 #include <linux/fs.h>
18 #include <linux/qnx4_fs.h>
19 #include <linux/stat.h>
20 #include <linux/kernel.h>
21 #include <linux/string.h>
22 #include <linux/buffer_head.h>
23 #include <linux/bitops.h>
24
25 #if 0
26 int qnx4_new_block(struct super_block *sb)
27 {
28 return 0;
29 }
30 #endif /* 0 */
31
32 static void count_bits(register const char *bmPart, register int size,
33 int *const tf)
34 {
35 char b;
36 int tot = *tf;
37
38 if (size > QNX4_BLOCK_SIZE) {
39 size = QNX4_BLOCK_SIZE;
40 }
41 do {
42 b = *bmPart++;
43 if ((b & 1) == 0)
44 tot++;
45 if ((b & 2) == 0)
46 tot++;
47 if ((b & 4) == 0)
48 tot++;
49 if ((b & 8) == 0)
50 tot++;
51 if ((b & 16) == 0)
52 tot++;
53 if ((b & 32) == 0)
54 tot++;
55 if ((b & 64) == 0)
56 tot++;
57 if ((b & 128) == 0)
58 tot++;
59 size--;
60 } while (size != 0);
61 *tf = tot;
62 }
63
64 unsigned long qnx4_count_free_blocks(struct super_block *sb)
65 {
66 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
67 int total = 0;
68 int total_free = 0;
69 int offset = 0;
70 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
71 struct buffer_head *bh;
72
73 while (total < size) {
74 if ((bh = sb_bread(sb, start + offset)) == NULL) {
75 printk("qnx4: I/O error in counting free blocks\n");
76 break;
77 }
78 count_bits(bh->b_data, size - total, &total_free);
79 brelse(bh);
80 total += QNX4_BLOCK_SIZE;
81 offset++;
82 }
83
84 return total_free;
85 }
86
87 #ifdef CONFIG_QNX4FS_RW
88
89 int qnx4_is_free(struct super_block *sb, long block)
90 {
91 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
92 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
93 struct buffer_head *bh;
94 const char *g;
95 int ret = -EIO;
96
97 start += block / (QNX4_BLOCK_SIZE * 8);
98 QNX4DEBUG(("qnx4: is_free requesting block [%lu], bitmap in block [%lu]\n",
99 (unsigned long) block, (unsigned long) start));
100 (void) size; /* CHECKME */
101 bh = sb_bread(sb, start);
102 if (bh == NULL) {
103 return -EIO;
104 }
105 g = bh->b_data + (block % QNX4_BLOCK_SIZE);
106 if (((*g) & (1 << (block % 8))) == 0) {
107 QNX4DEBUG(("qnx4: is_free -> block is free\n"));
108 ret = 1;
109 } else {
110 QNX4DEBUG(("qnx4: is_free -> block is busy\n"));
111 ret = 0;
112 }
113 brelse(bh);
114
115 return ret;
116 }
117
118 int qnx4_set_bitmap(struct super_block *sb, long block, int busy)
119 {
120 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
121 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
122 struct buffer_head *bh;
123 char *g;
124
125 start += block / (QNX4_BLOCK_SIZE * 8);
126 QNX4DEBUG(("qnx4: set_bitmap requesting block [%lu], bitmap in block [%lu]\n",
127 (unsigned long) block, (unsigned long) start));
128 (void) size; /* CHECKME */
129 bh = sb_bread(sb, start);
130 if (bh == NULL) {
131 return -EIO;
132 }
133 g = bh->b_data + (block % QNX4_BLOCK_SIZE);
134 if (busy == 0) {
135 (*g) &= ~(1 << (block % 8));
136 } else {
137 (*g) |= (1 << (block % 8));
138 }
139 mark_buffer_dirty(bh);
140 brelse(bh);
141
142 return 0;
143 }
144
145 static void qnx4_clear_inode(struct inode *inode)
146 {
147 struct qnx4_inode_entry *qnx4_ino = qnx4_raw_inode(inode);
148 /* What for? */
149 memset(qnx4_ino->di_fname, 0, sizeof qnx4_ino->di_fname);
150 qnx4_ino->di_size = 0;
151 qnx4_ino->di_num_xtnts = 0;
152 qnx4_ino->di_mode = 0;
153 qnx4_ino->di_status = 0;
154 }
155
156 void qnx4_free_inode(struct inode *inode)
157 {
158 if (inode->i_ino < 1) {
159 printk("free_inode: inode 0 or nonexistent inode\n");
160 return;
161 }
162 qnx4_clear_inode(inode);
163 clear_inode(inode);
164 }
165
166 #endif
167
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