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
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
|
/*
* linux/fs/sysv/ialloc.c
*
* minix/bitmap.c
* Copyright (C) 1991, 1992 Linus Torvalds
*
* ext/freelists.c
* Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
*
* xenix/alloc.c
* Copyright (C) 1992 Doug Evans
*
* coh/alloc.c
* Copyright (C) 1993 Pascal Haible, Bruno Haible
*
* sysv/ialloc.c
* Copyright (C) 1993 Bruno Haible
*
* This file contains code for allocating/freeing inodes.
*/
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include "sysv.h"
/* We don't trust the value of
sb->sv_sbd2->s_tinode = *sb->sv_sb_total_free_inodes
but we nevertheless keep it up to date. */
/* An inode on disk is considered free if both i_mode == 0 and i_nlink == 0. */
/* return &sb->sv_sb_fic_inodes[i] = &sbd->s_inode[i]; */
static inline sysv_ino_t *
sv_sb_fic_inode(struct super_block * sb, unsigned int i)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
if (sbi->s_bh1 == sbi->s_bh2)
return &sbi->s_sb_fic_inodes[i];
else {
/* 512 byte Xenix FS */
unsigned int offset = offsetof(struct xenix_super_block, s_inode[i]);
if (offset < 512)
return (sysv_ino_t*)(sbi->s_sbd1 + offset);
else
return (sysv_ino_t*)(sbi->s_sbd2 + offset);
}
}
struct sysv_inode *
sysv_raw_inode(struct super_block *sb, unsigned ino, struct buffer_head **bh)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
struct sysv_inode *res;
int block = sbi->s_firstinodezone + sbi->s_block_base;
block += (ino-1) >> sbi->s_inodes_per_block_bits;
*bh = sb_bread(sb, block);
if (!*bh)
return NULL;
res = (struct sysv_inode *)(*bh)->b_data;
return res + ((ino-1) & sbi->s_inodes_per_block_1);
}
static int refill_free_cache(struct super_block *sb)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
struct buffer_head * bh;
struct sysv_inode * raw_inode;
int i = 0, ino;
ino = SYSV_ROOT_INO+1;
raw_inode = sysv_raw_inode(sb, ino, &bh);
if (!raw_inode)
goto out;
while (ino <= sbi->s_ninodes) {
if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0) {
*sv_sb_fic_inode(sb,i++) = cpu_to_fs16(SYSV_SB(sb), ino);
if (i == sbi->s_fic_size)
break;
}
if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
brelse(bh);
raw_inode = sysv_raw_inode(sb, ino, &bh);
if (!raw_inode)
goto out;
} else
raw_inode++;
}
brelse(bh);
out:
return i;
}
void sysv_free_inode(struct inode * inode)
{
struct super_block *sb = inode->i_sb;
struct sysv_sb_info *sbi = SYSV_SB(sb);
unsigned int ino;
struct buffer_head * bh;
struct sysv_inode * raw_inode;
unsigned count;
sb = inode->i_sb;
ino = inode->i_ino;
if (ino <= SYSV_ROOT_INO || ino > sbi->s_ninodes) {
printk("sysv_free_inode: inode 0,1,2 or nonexistent inode\n");
return;
}
raw_inode = sysv_raw_inode(sb, ino, &bh);
if (!raw_inode) {
printk("sysv_free_inode: unable to read inode block on device "
"%s\n", inode->i_sb->s_id);
return;
}
mutex_lock(&sbi->s_lock);
count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
if (count < sbi->s_fic_size) {
*sv_sb_fic_inode(sb,count++) = cpu_to_fs16(sbi, ino);
*sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
}
fs16_add(sbi, sbi->s_sb_total_free_inodes, 1);
dirty_sb(sb);
memset(raw_inode, 0, sizeof(struct sysv_inode));
mark_buffer_dirty(bh);
mutex_unlock(&sbi->s_lock);
brelse(bh);
}
struct inode * sysv_new_inode(const struct inode * dir, umode_t mode)
{
struct super_block *sb = dir->i_sb;
struct sysv_sb_info *sbi = SYSV_SB(sb);
struct inode *inode;
sysv_ino_t ino;
unsigned count;
struct writeback_control wbc = {
.sync_mode = WB_SYNC_NONE
};
inode = new_inode(sb);
if (!inode)
return ERR_PTR(-ENOMEM);
mutex_lock(&sbi->s_lock);
count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
if (count == 0 || (*sv_sb_fic_inode(sb,count-1) == 0)) {
count = refill_free_cache(sb);
if (count == 0) {
iput(inode);
mutex_unlock(&sbi->s_lock);
return ERR_PTR(-ENOSPC);
}
}
/* Now count > 0. */
ino = *sv_sb_fic_inode(sb,--count);
*sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
fs16_add(sbi, sbi->s_sb_total_free_inodes, -1);
dirty_sb(sb);
inode_init_owner(inode, dir, mode);
inode->i_ino = fs16_to_cpu(sbi, ino);
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
inode->i_blocks = 0;
memset(SYSV_I(inode)->i_data, 0, sizeof(SYSV_I(inode)->i_data));
SYSV_I(inode)->i_dir_start_lookup = 0;
insert_inode_hash(inode);
mark_inode_dirty(inode);
sysv_write_inode(inode, &wbc); /* ensure inode not allocated again */
mark_inode_dirty(inode); /* cleared by sysv_write_inode() */
/* That's it. */
mutex_unlock(&sbi->s_lock);
return inode;
}
unsigned long sysv_count_free_inodes(struct super_block * sb)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
struct buffer_head * bh;
struct sysv_inode * raw_inode;
int ino, count, sb_count;
mutex_lock(&sbi->s_lock);
sb_count = fs16_to_cpu(sbi, *sbi->s_sb_total_free_inodes);
if (0)
goto trust_sb;
/* this causes a lot of disk traffic ... */
count = 0;
ino = SYSV_ROOT_INO+1;
raw_inode = sysv_raw_inode(sb, ino, &bh);
if (!raw_inode)
goto Eio;
while (ino <= sbi->s_ninodes) {
if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
count++;
if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
brelse(bh);
raw_inode = sysv_raw_inode(sb, ino, &bh);
if (!raw_inode)
goto Eio;
} else
raw_inode++;
}
brelse(bh);
if (count != sb_count)
goto Einval;
out:
mutex_unlock(&sbi->s_lock);
return count;
Einval:
printk("sysv_count_free_inodes: "
"free inode count was %d, correcting to %d\n",
sb_count, count);
if (!(sb->s_flags & MS_RDONLY)) {
*sbi->s_sb_total_free_inodes = cpu_to_fs16(SYSV_SB(sb), count);
dirty_sb(sb);
}
goto out;
Eio:
printk("sysv_count_free_inodes: unable to read inode table\n");
trust_sb:
count = sb_count;
goto out;
}
|
