2
* ensure meta data operations are performed synchronously
4
* Copyright (C) Andrew Tridgell 2007
6
* This program is free software; you can redistribute it and/or modify
7
* it under the terms of the GNU General Public License as published by
8
* the Free Software Foundation; either version 2 of the License, or
9
* (at your option) any later version.
11
* This program is distributed in the hope that it will be useful,
12
* but WITHOUT ANY WARRANTY; without even the implied warranty of
13
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14
* GNU General Public License for more details.
16
* You should have received a copy of the GNU General Public License
17
* along with this program; if not, write to the Free Software
18
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25
Some filesystems (even some journaled filesystems) require that a
26
fsync() be performed on many meta data operations to ensure that the
27
operation is guaranteed to remain in the filesystem after a power
28
failure. This is particularly important for some cluster filesystems
29
which are participating in a node failover system with clustered
32
On those filesystems this module provides a way to perform those
37
most of the performance loss with this module is in fsync on close().
38
You can disable that with syncops:onclose = no
40
static bool sync_onclose;
43
given a filename, find the parent directory
45
static char *parent_dir(TALLOC_CTX *mem_ctx, const char *name)
47
const char *p = strrchr(name, '/');
49
return talloc_strdup(mem_ctx, ".");
51
return talloc_strndup(mem_ctx, name, (p+1) - name);
55
fsync a directory by name
57
static void syncops_sync_directory(const char *dname)
60
int fd = open(dname, O_DIRECTORY|O_RDONLY);
66
DIR *d = opendir(dname);
75
sync two meta data changes for 2 names
77
static void syncops_two_names(const char *name1, const char *name2)
79
TALLOC_CTX *tmp_ctx = talloc_new(NULL);
80
char *parent1, *parent2;
81
parent1 = parent_dir(tmp_ctx, name1);
82
parent2 = parent_dir(tmp_ctx, name2);
83
if (!parent1 || !parent2) {
87
syncops_sync_directory(parent1);
88
if (strcmp(parent1, parent2) != 0) {
89
syncops_sync_directory(parent2);
95
sync two meta data changes for 1 names
97
static void syncops_name(const char *name)
100
parent = parent_dir(NULL, name);
102
syncops_sync_directory(parent);
109
rename needs special handling, as we may need to fsync two directories
111
static int syncops_rename(vfs_handle_struct *handle,
112
const char *oldname, const char *newname)
114
int ret = SMB_VFS_NEXT_RENAME(handle, oldname, newname);
116
syncops_two_names(oldname, newname);
121
/* handle the rest with a macro */
122
#define SYNCOPS_NEXT(op, fname, args) do { \
123
int ret = SMB_VFS_NEXT_ ## op args; \
124
if (ret == 0 && fname) syncops_name(fname); \
128
static int syncops_symlink(vfs_handle_struct *handle,
129
const char *oldname, const char *newname)
131
SYNCOPS_NEXT(SYMLINK, newname, (handle, oldname, newname));
134
static int syncops_link(vfs_handle_struct *handle,
135
const char *oldname, const char *newname)
137
SYNCOPS_NEXT(LINK, newname, (handle, oldname, newname));
140
static int syncops_open(vfs_handle_struct *handle,
141
const char *fname, files_struct *fsp, int flags, mode_t mode)
143
SYNCOPS_NEXT(OPEN, (flags&O_CREAT?fname:NULL), (handle, fname, fsp, flags, mode));
146
static int syncops_unlink(vfs_handle_struct *handle, const char *fname)
148
SYNCOPS_NEXT(UNLINK, fname, (handle, fname));
151
static int syncops_mknod(vfs_handle_struct *handle,
152
const char *fname, mode_t mode, SMB_DEV_T dev)
154
SYNCOPS_NEXT(MKNOD, fname, (handle, fname, mode, dev));
157
static int syncops_mkdir(vfs_handle_struct *handle, const char *fname, mode_t mode)
159
SYNCOPS_NEXT(MKDIR, fname, (handle, fname, mode));
162
static int syncops_rmdir(vfs_handle_struct *handle, const char *fname)
164
SYNCOPS_NEXT(RMDIR, fname, (handle, fname));
167
/* close needs to be handled specially */
168
static int syncops_close(vfs_handle_struct *handle, files_struct *fsp)
170
if (fsp->can_write && sync_onclose) {
171
/* ideally we'd only do this if we have written some
172
data, but there is no flag for that in fsp yet. */
175
return SMB_VFS_NEXT_CLOSE(handle, fsp);
179
/* VFS operations structure */
181
static vfs_op_tuple syncops_ops[] = {
182
/* directory operations */
183
{SMB_VFS_OP(syncops_mkdir), SMB_VFS_OP_MKDIR, SMB_VFS_LAYER_TRANSPARENT},
184
{SMB_VFS_OP(syncops_rmdir), SMB_VFS_OP_RMDIR, SMB_VFS_LAYER_TRANSPARENT},
186
/* File operations */
187
{SMB_VFS_OP(syncops_open), SMB_VFS_OP_OPEN, SMB_VFS_LAYER_TRANSPARENT},
188
{SMB_VFS_OP(syncops_rename), SMB_VFS_OP_RENAME, SMB_VFS_LAYER_TRANSPARENT},
189
{SMB_VFS_OP(syncops_unlink), SMB_VFS_OP_UNLINK, SMB_VFS_LAYER_TRANSPARENT},
190
{SMB_VFS_OP(syncops_symlink), SMB_VFS_OP_SYMLINK, SMB_VFS_LAYER_TRANSPARENT},
191
{SMB_VFS_OP(syncops_link), SMB_VFS_OP_LINK, SMB_VFS_LAYER_TRANSPARENT},
192
{SMB_VFS_OP(syncops_mknod), SMB_VFS_OP_MKNOD, SMB_VFS_LAYER_TRANSPARENT},
193
{SMB_VFS_OP(syncops_close), SMB_VFS_OP_CLOSE, SMB_VFS_LAYER_TRANSPARENT},
195
{SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
198
NTSTATUS vfs_syncops_init(void)
202
ret = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "syncops", syncops_ops);
204
if (!NT_STATUS_IS_OK(ret))
207
sync_onclose = lp_parm_bool(-1, "syncops", "onclose", true);