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 static int syncops_renameat(vfs_handle_struct *handle,
151 files_struct *srcfsp,
152 const struct smb_filename *smb_fname_src,
153 files_struct *dstfsp,
154 const struct smb_filename *smb_fname_dst)
158 struct syncops_config_data *config;
160 SMB_VFS_HANDLE_GET_DATA(handle, config,
161 struct syncops_config_data,
164 ret = SMB_VFS_NEXT_RENAMEAT(handle,
169 if (ret == 0 && config->onmeta && !config->disable) {
170 syncops_two_names(smb_fname_src->base_name,
171 smb_fname_dst->base_name);
176 #define SYNCOPS_NEXT_SMB_FNAME(op, fname, args) do { \
178 struct syncops_config_data *config; \
179 SMB_VFS_HANDLE_GET_DATA(handle, config, \
180 struct syncops_config_data, \
182 ret = SMB_VFS_NEXT_ ## op args; \
184 && config->onmeta && !config->disable \
185 && fname) syncops_smb_fname(fname); \
189 static int syncops_symlink(vfs_handle_struct *handle,
190 const char *link_contents,
191 const struct smb_filename *new_smb_fname)
194 struct syncops_config_data *config;
196 SMB_VFS_HANDLE_GET_DATA(handle, config,
197 struct syncops_config_data,
200 ret = SMB_VFS_NEXT_SYMLINK(handle, link_contents, new_smb_fname);
201 if (ret == 0 && config->onmeta && !config->disable) {
202 syncops_two_names(link_contents,
203 new_smb_fname->base_name);
208 static int syncops_link(vfs_handle_struct *handle,
209 const struct smb_filename *old_smb_fname,
210 const struct smb_filename *new_smb_fname)
213 struct syncops_config_data *config;
215 SMB_VFS_HANDLE_GET_DATA(handle, config,
216 struct syncops_config_data,
219 ret = SMB_VFS_NEXT_LINK(handle, old_smb_fname, new_smb_fname);
220 if (ret == 0 && config->onmeta && !config->disable) {
221 syncops_two_names(old_smb_fname->base_name,
222 new_smb_fname->base_name);
227 static int syncops_open(vfs_handle_struct *handle,
228 struct smb_filename *smb_fname, files_struct *fsp,
229 int flags, mode_t mode)
231 SYNCOPS_NEXT_SMB_FNAME(OPEN, (flags&O_CREAT?smb_fname:NULL),
232 (handle, smb_fname, fsp, flags, mode));
235 static int syncops_unlink(vfs_handle_struct *handle,
236 const struct smb_filename *smb_fname)
238 SYNCOPS_NEXT_SMB_FNAME(UNLINK, smb_fname, (handle, smb_fname));
241 static int syncops_mknod(vfs_handle_struct *handle,
242 const struct smb_filename *smb_fname,
246 SYNCOPS_NEXT_SMB_FNAME(MKNOD,
247 smb_fname, (handle, smb_fname, mode, dev));
250 static int syncops_mkdir(vfs_handle_struct *handle,
251 const struct smb_filename *smb_fname,
254 SYNCOPS_NEXT_SMB_FNAME(MKDIR, smb_fname, (handle, smb_fname, mode));
257 static int syncops_rmdir(vfs_handle_struct *handle,
258 const struct smb_filename *smb_fname)
260 SYNCOPS_NEXT_SMB_FNAME(RMDIR, smb_fname, (handle, smb_fname));
263 /* close needs to be handled specially */
264 static int syncops_close(vfs_handle_struct *handle, files_struct *fsp)
266 struct syncops_config_data *config;
268 SMB_VFS_HANDLE_GET_DATA(handle, config,
269 struct syncops_config_data,
272 if (fsp->can_write && config->onclose) {
273 /* ideally we'd only do this if we have written some
274 data, but there is no flag for that in fsp yet. */
277 return SMB_VFS_NEXT_CLOSE(handle, fsp);
280 static int syncops_connect(struct vfs_handle_struct *handle, const char *service,
284 struct syncops_config_data *config;
285 int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
290 config = talloc_zero(handle->conn, struct syncops_config_data);
292 SMB_VFS_NEXT_DISCONNECT(handle);
293 DEBUG(0, ("talloc_zero() failed\n"));
297 config->onclose = lp_parm_bool(SNUM(handle->conn), "syncops",
300 config->onmeta = lp_parm_bool(SNUM(handle->conn), "syncops",
303 config->disable = lp_parm_bool(SNUM(handle->conn), "syncops",
306 SMB_VFS_HANDLE_SET_DATA(handle, config,
307 NULL, struct syncops_config_data,
314 static struct vfs_fn_pointers vfs_syncops_fns = {
315 .connect_fn = syncops_connect,
316 .mkdir_fn = syncops_mkdir,
317 .rmdir_fn = syncops_rmdir,
318 .open_fn = syncops_open,
319 .rename_fn = syncops_rename,
320 .renameat_fn = syncops_renameat,
321 .unlink_fn = syncops_unlink,
322 .symlink_fn = syncops_symlink,
323 .link_fn = syncops_link,
324 .mknod_fn = syncops_mknod,
325 .close_fn = syncops_close,
329 NTSTATUS vfs_syncops_init(TALLOC_CTX *ctx)
333 ret = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "syncops",
336 if (!NT_STATUS_IS_OK(ret))