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
|
// SPDX-License-Identifier: GPL-2.0+ OR Apache-2.0
#include "erofs/diskbuf.h"
#include "erofs/internal.h"
#include "erofs/print.h"
#include <stdio.h>
#include <errno.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
/* A simple approach to avoid creating too many temporary files */
static struct erofs_diskbufstrm {
erofs_atomic_t count;
u64 tailoffset, devpos;
int fd;
unsigned int alignsize;
bool locked;
} *dbufstrm;
int erofs_diskbuf_getfd(struct erofs_diskbuf *db, u64 *fpos)
{
const struct erofs_diskbufstrm *strm = db->sp;
u64 offset;
if (!strm)
return -1;
offset = db->offset + strm->devpos;
if (fpos)
*fpos = offset;
return strm->fd;
}
int erofs_diskbuf_reserve(struct erofs_diskbuf *db, int sid, u64 *off)
{
struct erofs_diskbufstrm *strm = dbufstrm + sid;
if (strm->tailoffset & (strm->alignsize - 1)) {
strm->tailoffset = round_up(strm->tailoffset, strm->alignsize);
}
db->offset = strm->tailoffset;
if (off)
*off = db->offset + strm->devpos;
db->sp = strm;
(void)erofs_atomic_inc_return(&strm->count);
strm->locked = true; /* TODO: need a real lock for MT */
return strm->fd;
}
void erofs_diskbuf_commit(struct erofs_diskbuf *db, u64 len)
{
struct erofs_diskbufstrm *strm = db->sp;
DBG_BUGON(!strm);
DBG_BUGON(!strm->locked);
DBG_BUGON(strm->tailoffset != db->offset);
strm->tailoffset += len;
}
void erofs_diskbuf_close(struct erofs_diskbuf *db)
{
struct erofs_diskbufstrm *strm = db->sp;
DBG_BUGON(!strm);
DBG_BUGON(erofs_atomic_read(&strm->count) <= 1);
(void)erofs_atomic_dec_return(&strm->count);
db->sp = NULL;
}
int erofs_tmpfile(void)
{
#define TRAILER "tmp.XXXXXXXXXX"
char buf[PATH_MAX];
int fd;
umode_t u;
(void)snprintf(buf, sizeof(buf), "%s/" TRAILER,
getenv("TMPDIR") ?: "/tmp");
fd = mkstemp(buf);
if (fd < 0)
return -errno;
unlink(buf);
u = umask(0);
(void)umask(u);
(void)fchmod(fd, 0666 & ~u);
return fd;
}
int erofs_diskbuf_init(unsigned int nstrms)
{
struct erofs_diskbufstrm *strm;
strm = calloc(nstrms + 1, sizeof(*strm));
if (!strm)
return -ENOMEM;
strm[nstrms].fd = -1;
dbufstrm = strm;
for (; strm < dbufstrm + nstrms; ++strm) {
struct stat st;
/* try to use the devfd for regfiles on stream 0 */
if (strm == dbufstrm && !g_sbi.bdev.ops) {
strm->devpos = 1ULL << 40;
if (!ftruncate(g_sbi.bdev.fd, strm->devpos << 1)) {
strm->fd = dup(g_sbi.bdev.fd);
goto setupone;
}
}
strm->devpos = 0;
strm->fd = erofs_tmpfile();
if (strm->fd < 0)
return -ENOSPC;
setupone:
strm->tailoffset = 0;
erofs_atomic_set(&strm->count, 1);
if (fstat(strm->fd, &st))
return -errno;
strm->alignsize = max_t(u32, st.st_blksize, getpagesize());
}
return 0;
}
void erofs_diskbuf_exit(void)
{
struct erofs_diskbufstrm *strm;
if (!dbufstrm)
return;
for (strm = dbufstrm; strm->fd >= 0; ++strm) {
DBG_BUGON(erofs_atomic_read(&strm->count) != 1);
close(strm->fd);
strm->fd = -1;
}
free(dbufstrm);
}
|
