6b13f685e
 김민수
BSP 최초 추가
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <asm/div64.h>
#include "omfs.h"
unsigned long omfs_count_free(struct super_block *sb)
{
unsigned int i;
unsigned long sum = 0;
struct omfs_sb_info *sbi = OMFS_SB(sb);
int nbits = sb->s_blocksize * 8;
for (i = 0; i < sbi->s_imap_size; i++)
sum += nbits - bitmap_weight(sbi->s_imap[i], nbits);
return sum;
}
/*
* Counts the run of zero bits starting at bit up to max.
* It handles the case where a run might spill over a buffer.
* Called with bitmap lock.
*/
static int count_run(unsigned long **addr, int nbits,
int addrlen, int bit, int max)
{
int count = 0;
int x;
for (; addrlen > 0; addrlen--, addr++) {
x = find_next_bit(*addr, nbits, bit);
count += x - bit;
if (x < nbits || count > max)
return min(count, max);
bit = 0;
}
return min(count, max);
}
/*
* Sets or clears the run of count bits starting with bit.
* Called with bitmap lock.
*/
static int set_run(struct super_block *sb, int map,
int nbits, int bit, int count, int set)
{
int i;
int err;
struct buffer_head *bh;
struct omfs_sb_info *sbi = OMFS_SB(sb);
err = -ENOMEM;
bh = sb_bread(sb, clus_to_blk(sbi, sbi->s_bitmap_ino) + map);
if (!bh)
goto out;
for (i = 0; i < count; i++, bit++) {
if (bit >= nbits) {
bit = 0;
map++;
mark_buffer_dirty(bh);
brelse(bh);
bh = sb_bread(sb,
clus_to_blk(sbi, sbi->s_bitmap_ino) + map);
if (!bh)
goto out;
}
if (set) {
set_bit(bit, sbi->s_imap[map]);
set_bit(bit, (unsigned long *)bh->b_data);
} else {
clear_bit(bit, sbi->s_imap[map]);
clear_bit(bit, (unsigned long *)bh->b_data);
}
}
mark_buffer_dirty(bh);
brelse(bh);
err = 0;
out:
return err;
}
/*
* Tries to allocate exactly one block. Returns true if successful.
*/
int omfs_allocate_block(struct super_block *sb, u64 block)
{
struct buffer_head *bh;
struct omfs_sb_info *sbi = OMFS_SB(sb);
int bits_per_entry = 8 * sb->s_blocksize;
unsigned int map, bit;
int ret = 0;
u64 tmp;
tmp = block;
bit = do_div(tmp, bits_per_entry);
map = tmp;
mutex_lock(&sbi->s_bitmap_lock);
if (map >= sbi->s_imap_size || test_and_set_bit(bit, sbi->s_imap[map]))
goto out;
if (sbi->s_bitmap_ino > 0) {
bh = sb_bread(sb, clus_to_blk(sbi, sbi->s_bitmap_ino) + map);
if (!bh)
goto out;
set_bit(bit, (unsigned long *)bh->b_data);
mark_buffer_dirty(bh);
brelse(bh);
}
ret = 1;
out:
mutex_unlock(&sbi->s_bitmap_lock);
return ret;
}
/*
* Tries to allocate a set of blocks. The request size depends on the
* type: for inodes, we must allocate sbi->s_mirrors blocks, and for file
* blocks, we try to allocate sbi->s_clustersize, but can always get away
* with just one block.
*/
int omfs_allocate_range(struct super_block *sb,
int min_request,
int max_request,
u64 *return_block,
int *return_size)
{
struct omfs_sb_info *sbi = OMFS_SB(sb);
int bits_per_entry = 8 * sb->s_blocksize;
int ret = 0;
int i, run, bit;
mutex_lock(&sbi->s_bitmap_lock);
for (i = 0; i < sbi->s_imap_size; i++) {
bit = 0;
while (bit < bits_per_entry) {
bit = find_next_zero_bit(sbi->s_imap[i], bits_per_entry,
bit);
if (bit == bits_per_entry)
break;
run = count_run(&sbi->s_imap[i], bits_per_entry,
sbi->s_imap_size-i, bit, max_request);
if (run >= min_request)
goto found;
bit += run;
}
}
ret = -ENOSPC;
goto out;
found:
*return_block = i * bits_per_entry + bit;
*return_size = run;
ret = set_run(sb, i, bits_per_entry, bit, run, 1);
out:
mutex_unlock(&sbi->s_bitmap_lock);
return ret;
}
/*
* Clears count bits starting at a given block.
*/
int omfs_clear_range(struct super_block *sb, u64 block, int count)
{
struct omfs_sb_info *sbi = OMFS_SB(sb);
int bits_per_entry = 8 * sb->s_blocksize;
u64 tmp;
unsigned int map, bit;
int ret;
tmp = block;
bit = do_div(tmp, bits_per_entry);
map = tmp;
if (map >= sbi->s_imap_size)
return 0;
mutex_lock(&sbi->s_bitmap_lock);
ret = set_run(sb, map, bits_per_entry, bit, count, 0);
mutex_unlock(&sbi->s_bitmap_lock);
return ret;
}
|