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review.evervolv.com / android_kernel_htc_msm8960 / ada70d9425bcc5e376fef8591e4e76e204c0834c / . / fs / qnx4 / bitmap.c
blob: 991253927658bf2a2673c70c8ec99789f709f59f [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700[diff] [blame]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/config.h>
17#include <linux/time.h>
18#include <linux/fs.h>
19#include <linux/qnx4_fs.h>
20#include <linux/stat.h>
21#include <linux/kernel.h>
22#include <linux/string.h>
23#include <linux/buffer_head.h>
24#include <linux/bitops.h>
25
26int qnx4_new_block(struct super_block *sb)
27{
28 return 0;
29}
30
31static void count_bits(register const char *bmPart, register int size,
32 int *const tf)
33{
34 char b;
35 int tot = *tf;
36
37 if (size > QNX4_BLOCK_SIZE) {
38 size = QNX4_BLOCK_SIZE;
39 }
40 do {
41 b = *bmPart++;
42 if ((b & 1) == 0)
43 tot++;
44 if ((b & 2) == 0)
45 tot++;
46 if ((b & 4) == 0)
47 tot++;
48 if ((b & 8) == 0)
49 tot++;
50 if ((b & 16) == 0)
51 tot++;
52 if ((b & 32) == 0)
53 tot++;
54 if ((b & 64) == 0)
55 tot++;
56 if ((b & 128) == 0)
57 tot++;
58 size--;
59 } while (size != 0);
60 *tf = tot;
61}
62
63unsigned long qnx4_count_free_blocks(struct super_block *sb)
64{
65 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
66 int total = 0;
67 int total_free = 0;
68 int offset = 0;
69 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
70 struct buffer_head *bh;
71
72 while (total < size) {
73 if ((bh = sb_bread(sb, start + offset)) == NULL) {
74 printk("qnx4: I/O error in counting free blocks\n");
75 break;
76 }
77 count_bits(bh->b_data, size - total, &total_free);
78 brelse(bh);
79 total += QNX4_BLOCK_SIZE;
80 offset++;
81 }
82
83 return total_free;
84}
85
86#ifdef CONFIG_QNX4FS_RW
87
88int qnx4_is_free(struct super_block *sb, long block)
89{
90 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
91 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
92 struct buffer_head *bh;
93 const char *g;
94 int ret = -EIO;
95
96 start += block / (QNX4_BLOCK_SIZE * 8);
97 QNX4DEBUG(("qnx4: is_free requesting block [%lu], bitmap in block [%lu]\n",
98 (unsigned long) block, (unsigned long) start));
99 (void) size; /* CHECKME */
100 bh = sb_bread(sb, start);
101 if (bh == NULL) {
102 return -EIO;
103 }
104 g = bh->b_data + (block % QNX4_BLOCK_SIZE);
105 if (((*g) & (1 << (block % 8))) == 0) {
106 QNX4DEBUG(("qnx4: is_free -> block is free\n"));
107 ret = 1;
108 } else {
109 QNX4DEBUG(("qnx4: is_free -> block is busy\n"));
110 ret = 0;
111 }
112 brelse(bh);
113
114 return ret;
115}
116
117int qnx4_set_bitmap(struct super_block *sb, long block, int busy)
118{
119 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
120 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
121 struct buffer_head *bh;
122 char *g;
123
124 start += block / (QNX4_BLOCK_SIZE * 8);
125 QNX4DEBUG(("qnx4: set_bitmap requesting block [%lu], bitmap in block [%lu]\n",
126 (unsigned long) block, (unsigned long) start));
127 (void) size; /* CHECKME */
128 bh = sb_bread(sb, start);
129 if (bh == NULL) {
130 return -EIO;
131 }
132 g = bh->b_data + (block % QNX4_BLOCK_SIZE);
133 if (busy == 0) {
134 (*g) &= ~(1 << (block % 8));
135 } else {
136 (*g) |= (1 << (block % 8));
137 }
138 mark_buffer_dirty(bh);
139 brelse(bh);
140
141 return 0;
142}
143
144static void qnx4_clear_inode(struct inode *inode)
145{
146 struct qnx4_inode_entry *qnx4_ino = qnx4_raw_inode(inode);
147 /* What for? */
148 memset(qnx4_ino->di_fname, 0, sizeof qnx4_ino->di_fname);
149 qnx4_ino->di_size = 0;
150 qnx4_ino->di_num_xtnts = 0;
151 qnx4_ino->di_mode = 0;
152 qnx4_ino->di_status = 0;
153}
154
155void qnx4_free_inode(struct inode *inode)
156{
157 if (inode->i_ino < 1) {
158 printk("free_inode: inode 0 or nonexistent inode\n");
159 return;
160 }
161 qnx4_clear_inode(inode);
162 clear_inode(inode);
163}
164
165#endif