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
|
/*
* Copyright (c) James Peach 2006
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
/* Commit data module.
*
* The purpose of this module is to flush data to disk at regular intervals,
* just like the NFS commit operation. There's two rationales for this. First,
* it minimises the data loss in case of a power outage without incurring
* the poor performance of synchronous I/O. Second, a steady flush rate
* can produce better throughput than suddenly dumping massive amounts of
* writes onto a disk.
*
* Tunables:
*
* commit: dthresh Amount of dirty data that can accumulate
* before we commit (sync) it.
*
* commit: debug Debug level at which to emit messages.
*
*/
#define MODULE "commit"
static int module_debug;
struct commit_info
{
SMB_OFF_T dbytes; /* Dirty (uncommitted) bytes */
SMB_OFF_T dthresh; /* Dirty data threshold */
};
static void commit_all(
struct vfs_handle_struct * handle,
files_struct * fsp)
{
struct commit_info *c;
if ((c = VFS_FETCH_FSP_EXTENSION(handle, fsp))) {
if (c->dbytes) {
DEBUG(module_debug,
("%s: flushing %lu dirty bytes\n",
MODULE, (unsigned long)c->dbytes));
fdatasync(fsp->fh->fd);
c->dbytes = 0;
}
}
}
static void commit(
struct vfs_handle_struct * handle,
files_struct * fsp,
ssize_t last_write)
{
struct commit_info *c;
if ((c = VFS_FETCH_FSP_EXTENSION(handle, fsp))) {
if (last_write > 0) {
c->dbytes += last_write;
}
if (c->dbytes > c->dthresh) {
DEBUG(module_debug,
("%s: flushing %lu dirty bytes\n",
MODULE, (unsigned long)c->dbytes));
fdatasync(fsp->fh->fd);
c->dbytes = 0;
}
}
}
static int commit_connect(
struct vfs_handle_struct * handle,
const char * service,
const char * user)
{
module_debug = lp_parm_int(SNUM(handle->conn), MODULE, "debug", 100);
return SMB_VFS_NEXT_CONNECT(handle, service, user);
}
static int commit_open(
vfs_handle_struct * handle,
const char * fname,
files_struct * fsp,
int flags,
mode_t mode)
{
SMB_OFF_T dthresh;
/* Don't bother with read-only files. */
if ((flags & O_ACCMODE) == O_RDONLY) {
return SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode);
}
dthresh = conv_str_size(lp_parm_const_string(SNUM(handle->conn),
MODULE, "dthresh", NULL));
if (dthresh > 0) {
struct commit_info * c;
c = VFS_ADD_FSP_EXTENSION(handle, fsp, struct commit_info);
if (c) {
c->dthresh = dthresh;
c->dbytes = 0;
}
}
return SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode);
}
static ssize_t commit_write(
vfs_handle_struct * handle,
files_struct * fsp,
int fd,
void * data,
size_t count)
{
ssize_t ret;
ret = SMB_VFS_NEXT_WRITE(handle, fsp, fd, data, count);
commit(handle, fsp, ret);
return ret;
}
static ssize_t commit_pwrite(
vfs_handle_struct * handle,
files_struct * fsp,
int fd,
void * data,
size_t count,
SMB_OFF_T offset)
{
ssize_t ret;
ret = SMB_VFS_NEXT_PWRITE(handle, fsp, fd, data, count, offset);
commit(handle, fsp, ret);
return ret;
}
static ssize_t commit_close(
vfs_handle_struct * handle,
files_struct * fsp,
int fd)
{
commit_all(handle, fsp);
return SMB_VFS_NEXT_CLOSE(handle, fsp, fd);
}
static vfs_op_tuple commit_ops [] =
{
{SMB_VFS_OP(commit_open),
SMB_VFS_OP_OPEN, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(commit_close),
SMB_VFS_OP_CLOSE, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(commit_write),
SMB_VFS_OP_WRITE, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(commit_pwrite),
SMB_VFS_OP_PWRITE, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(commit_connect),
SMB_VFS_OP_CONNECT, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
};
NTSTATUS vfs_commit_init(void);
NTSTATUS vfs_commit_init(void)
{
return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, MODULE, commit_ops);
}
|
