2 * ensure meta data operations are performed synchronously
4 * Copyright (C) Andrew Tridgell 2007
5 * Copyright (C) Christian Ambach, 2010-2011
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 #include "system/filesys.h"
24 #include "smbd/smbd.h"
28 Some filesystems (even some journaled filesystems) require that a
29 fsync() be performed on many meta data operations to ensure that the
30 operation is guaranteed to remain in the filesystem after a power
31 failure. This is particularly important for some cluster filesystems
32 which are participating in a node failover system with clustered
35 On those filesystems this module provides a way to perform those
38 most of the performance loss with this module is in fsync on close().
39 You can disable that with
41 that can be set either globally or per share.
43 On certain filesystems that only require the last data written to be
44 fsync()'ed, you can disable the metadata synchronization of this module with
46 This option can be set either globally or per share.
48 you can also disable the module completely for a share with
49 syncops:disable = true
53 struct syncops_config_data {
60 given a filename, find the parent directory
62 static char *parent_dir(TALLOC_CTX *mem_ctx, const char *name)
64 const char *p = strrchr(name, '/');
66 return talloc_strdup(mem_ctx, ".");
68 return talloc_strndup(mem_ctx, name, (p+1) - name);
72 fsync a directory by name
74 static void syncops_sync_directory(const char *dname)
77 int fd = open(dname, O_DIRECTORY|O_RDONLY);
83 DIR *d = opendir(dname);
92 sync two meta data changes for 2 names
94 static void syncops_two_names(const char *name1, const char *name2)
96 TALLOC_CTX *tmp_ctx = talloc_new(NULL);
97 char *parent1, *parent2;
98 parent1 = parent_dir(tmp_ctx, name1);
99 parent2 = parent_dir(tmp_ctx, name2);
100 if (!parent1 || !parent2) {
101 talloc_free(tmp_ctx);
104 syncops_sync_directory(parent1);
105 if (strcmp(parent1, parent2) != 0) {
106 syncops_sync_directory(parent2);
108 talloc_free(tmp_ctx);
112 sync two meta data changes for 1 names
114 static void syncops_smb_fname(const struct smb_filename *smb_fname)
117 if (smb_fname != NULL) {
118 parent = parent_dir(NULL, smb_fname->base_name);
119 if (parent != NULL) {
120 syncops_sync_directory(parent);
128 rename needs special handling, as we may need to fsync two directories
130 static int syncops_rename(vfs_handle_struct *handle,
131 const struct smb_filename *smb_fname_src,
132 const struct smb_filename *smb_fname_dst)
136 struct syncops_config_data *config;
138 SMB_VFS_HANDLE_GET_DATA(handle, config,
139 struct syncops_config_data,
142 ret = SMB_VFS_NEXT_RENAME(handle, smb_fname_src, smb_fname_dst);
143 if (ret == 0 && config->onmeta && !config->disable) {
144 syncops_two_names(smb_fname_src->base_name,
145 smb_fname_dst->base_name);
150 #define SYNCOPS_NEXT_SMB_FNAME(op, fname, args) do { \
152 struct syncops_config_data *config; \
153 SMB_VFS_HANDLE_GET_DATA(handle, config, \
154 struct syncops_config_data, \
156 ret = SMB_VFS_NEXT_ ## op args; \
158 && config->onmeta && !config->disable \
159 && fname) syncops_smb_fname(fname); \
163 static int syncops_symlink(vfs_handle_struct *handle,
164 const char *link_contents,
165 const struct smb_filename *new_smb_fname)
168 struct syncops_config_data *config;
170 SMB_VFS_HANDLE_GET_DATA(handle, config,
171 struct syncops_config_data,
174 ret = SMB_VFS_NEXT_SYMLINK(handle, link_contents, new_smb_fname);
175 if (ret == 0 && config->onmeta && !config->disable) {
176 syncops_two_names(link_contents,
177 new_smb_fname->base_name);
182 static int syncops_link(vfs_handle_struct *handle,
183 const struct smb_filename *old_smb_fname,
184 const struct smb_filename *new_smb_fname)
187 struct syncops_config_data *config;
189 SMB_VFS_HANDLE_GET_DATA(handle, config,
190 struct syncops_config_data,
193 ret = SMB_VFS_NEXT_LINK(handle, old_smb_fname, new_smb_fname);
194 if (ret == 0 && config->onmeta && !config->disable) {
195 syncops_two_names(old_smb_fname->base_name,
196 new_smb_fname->base_name);
201 static int syncops_open(vfs_handle_struct *handle,
202 struct smb_filename *smb_fname, files_struct *fsp,
203 int flags, mode_t mode)
205 SYNCOPS_NEXT_SMB_FNAME(OPEN, (flags&O_CREAT?smb_fname:NULL),
206 (handle, smb_fname, fsp, flags, mode));
209 static int syncops_unlink(vfs_handle_struct *handle,
210 const struct smb_filename *smb_fname)
212 SYNCOPS_NEXT_SMB_FNAME(UNLINK, smb_fname, (handle, smb_fname));
215 static int syncops_mknod(vfs_handle_struct *handle,
216 const struct smb_filename *smb_fname,
220 SYNCOPS_NEXT_SMB_FNAME(MKNOD,
221 smb_fname, (handle, smb_fname, mode, dev));
224 static int syncops_mkdir(vfs_handle_struct *handle,
225 const struct smb_filename *smb_fname,
228 SYNCOPS_NEXT_SMB_FNAME(MKDIR, smb_fname, (handle, smb_fname, mode));
231 static int syncops_rmdir(vfs_handle_struct *handle,
232 const struct smb_filename *smb_fname)
234 SYNCOPS_NEXT_SMB_FNAME(RMDIR, smb_fname, (handle, smb_fname));
237 /* close needs to be handled specially */
238 static int syncops_close(vfs_handle_struct *handle, files_struct *fsp)
240 struct syncops_config_data *config;
242 SMB_VFS_HANDLE_GET_DATA(handle, config,
243 struct syncops_config_data,
246 if (fsp->can_write && config->onclose) {
247 /* ideally we'd only do this if we have written some
248 data, but there is no flag for that in fsp yet. */
251 return SMB_VFS_NEXT_CLOSE(handle, fsp);
254 static int syncops_connect(struct vfs_handle_struct *handle, const char *service,
258 struct syncops_config_data *config;
259 int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
264 config = talloc_zero(handle->conn, struct syncops_config_data);
266 SMB_VFS_NEXT_DISCONNECT(handle);
267 DEBUG(0, ("talloc_zero() failed\n"));
271 config->onclose = lp_parm_bool(SNUM(handle->conn), "syncops",
274 config->onmeta = lp_parm_bool(SNUM(handle->conn), "syncops",
277 config->disable = lp_parm_bool(SNUM(handle->conn), "syncops",
280 SMB_VFS_HANDLE_SET_DATA(handle, config,
281 NULL, struct syncops_config_data,
288 static struct vfs_fn_pointers vfs_syncops_fns = {
289 .connect_fn = syncops_connect,
290 .mkdir_fn = syncops_mkdir,
291 .rmdir_fn = syncops_rmdir,
292 .open_fn = syncops_open,
293 .rename_fn = syncops_rename,
294 .unlink_fn = syncops_unlink,
295 .symlink_fn = syncops_symlink,
296 .link_fn = syncops_link,
297 .mknod_fn = syncops_mknod,
298 .close_fn = syncops_close,
302 NTSTATUS vfs_syncops_init(TALLOC_CTX *ctx)
306 ret = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "syncops",
309 if (!NT_STATUS_IS_OK(ret))