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 renameat needs special handling, as we may need to fsync two directories
130 static int syncops_renameat(vfs_handle_struct *handle,
131 files_struct *srcfsp,
132 const struct smb_filename *smb_fname_src,
133 files_struct *dstfsp,
134 const struct smb_filename *smb_fname_dst)
138 struct syncops_config_data *config;
140 SMB_VFS_HANDLE_GET_DATA(handle, config,
141 struct syncops_config_data,
144 ret = SMB_VFS_NEXT_RENAMEAT(handle,
149 if (ret == 0 && config->onmeta && !config->disable) {
150 syncops_two_names(smb_fname_src->base_name,
151 smb_fname_dst->base_name);
156 #define SYNCOPS_NEXT_SMB_FNAME(op, fname, args) do { \
158 struct syncops_config_data *config; \
159 SMB_VFS_HANDLE_GET_DATA(handle, config, \
160 struct syncops_config_data, \
162 ret = SMB_VFS_NEXT_ ## op args; \
164 && config->onmeta && !config->disable \
165 && fname) syncops_smb_fname(fname); \
169 static int syncops_symlinkat(vfs_handle_struct *handle,
170 const struct smb_filename *link_contents,
171 struct files_struct *dirfsp,
172 const struct smb_filename *new_smb_fname)
175 struct syncops_config_data *config;
177 SMB_VFS_HANDLE_GET_DATA(handle, config,
178 struct syncops_config_data,
181 ret = SMB_VFS_NEXT_SYMLINKAT(handle,
186 if (ret == 0 && config->onmeta && !config->disable) {
187 syncops_two_names(link_contents->base_name,
188 new_smb_fname->base_name);
193 static int syncops_linkat(vfs_handle_struct *handle,
194 files_struct *srcfsp,
195 const struct smb_filename *old_smb_fname,
196 files_struct *dstfsp,
197 const struct smb_filename *new_smb_fname,
201 struct syncops_config_data *config;
203 SMB_VFS_HANDLE_GET_DATA(handle, config,
204 struct syncops_config_data,
207 SMB_ASSERT(srcfsp == srcfsp->conn->cwd_fsp);
208 SMB_ASSERT(dstfsp == dstfsp->conn->cwd_fsp);
210 ret = SMB_VFS_NEXT_LINKAT(handle,
217 if (ret == 0 && config->onmeta && !config->disable) {
218 syncops_two_names(old_smb_fname->base_name,
219 new_smb_fname->base_name);
225 static int syncops_open(vfs_handle_struct *handle,
226 struct smb_filename *smb_fname, files_struct *fsp,
227 int flags, mode_t mode)
229 SYNCOPS_NEXT_SMB_FNAME(OPEN, (flags&O_CREAT?smb_fname:NULL),
230 (handle, smb_fname, fsp, flags, mode));
233 static int syncops_unlinkat(vfs_handle_struct *handle,
234 files_struct *dirfsp,
235 const struct smb_filename *smb_fname,
238 SYNCOPS_NEXT_SMB_FNAME(UNLINKAT,
246 static int syncops_mknodat(vfs_handle_struct *handle,
247 files_struct *dirfsp,
248 const struct smb_filename *smb_fname,
252 SYNCOPS_NEXT_SMB_FNAME(MKNODAT,
261 static int syncops_mkdirat(vfs_handle_struct *handle,
262 struct files_struct *dirfsp,
263 const struct smb_filename *smb_fname,
266 SYNCOPS_NEXT_SMB_FNAME(MKDIRAT,
274 /* close needs to be handled specially */
275 static int syncops_close(vfs_handle_struct *handle, files_struct *fsp)
277 struct syncops_config_data *config;
279 SMB_VFS_HANDLE_GET_DATA(handle, config,
280 struct syncops_config_data,
283 if (fsp->fsp_flags.can_write && config->onclose) {
284 /* ideally we'd only do this if we have written some
285 data, but there is no flag for that in fsp yet. */
288 return SMB_VFS_NEXT_CLOSE(handle, fsp);
291 static int syncops_connect(struct vfs_handle_struct *handle, const char *service,
295 struct syncops_config_data *config;
296 int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
301 config = talloc_zero(handle->conn, struct syncops_config_data);
303 SMB_VFS_NEXT_DISCONNECT(handle);
304 DEBUG(0, ("talloc_zero() failed\n"));
308 config->onclose = lp_parm_bool(SNUM(handle->conn), "syncops",
311 config->onmeta = lp_parm_bool(SNUM(handle->conn), "syncops",
314 config->disable = lp_parm_bool(SNUM(handle->conn), "syncops",
317 SMB_VFS_HANDLE_SET_DATA(handle, config,
318 NULL, struct syncops_config_data,
325 static struct vfs_fn_pointers vfs_syncops_fns = {
326 .connect_fn = syncops_connect,
327 .mkdirat_fn = syncops_mkdirat,
328 .open_fn = syncops_open,
329 .renameat_fn = syncops_renameat,
330 .unlinkat_fn = syncops_unlinkat,
331 .symlinkat_fn = syncops_symlinkat,
332 .linkat_fn = syncops_linkat,
333 .mknodat_fn = syncops_mknodat,
334 .close_fn = syncops_close,
338 NTSTATUS vfs_syncops_init(TALLOC_CTX *ctx)
342 ret = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "syncops",
345 if (!NT_STATUS_IS_OK(ret))