source: trunk/server/source4/ntvfs/posix/pvfs_lock.c

Last change on this file was 745, checked in by Silvan Scherrer, 13 years ago

Samba Server: updated trunk to 3.6.0
File size: 11.2 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3
4 POSIX NTVFS backend - locking
5
6 Copyright (C) Andrew Tridgell 2004
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
20*/
21
22#include "includes.h"
23#include "vfs_posix.h"
24#include "system/time.h"
25#include "../lib/util/dlinklist.h"
26#include "messaging/messaging.h"
27
28
29/*
30 check if we can perform IO on a range that might be locked
31*/
32NTSTATUS pvfs_check_lock(struct pvfs_state *pvfs,
33 struct pvfs_file *f,
34 uint32_t smbpid,
35 uint64_t offset, uint64_t count,
36 enum brl_type rw)
37{
38 if (!(pvfs->flags & PVFS_FLAG_STRICT_LOCKING)) {
39 return NT_STATUS_OK;
40 }
41
42 return brl_locktest(pvfs->brl_context,
43 f->brl_handle,
44 smbpid,
45 offset, count, rw);
46}
47
48/* this state structure holds information about a lock we are waiting on */
49struct pvfs_pending_lock {
50 struct pvfs_pending_lock *next, *prev;
51 struct pvfs_state *pvfs;
52 union smb_lock *lck;
53 struct pvfs_file *f;
54 struct ntvfs_request *req;
55 int pending_lock;
56 struct pvfs_wait *wait_handle;
57 struct timeval end_time;
58};
59
60/*
61 a secondary attempt to setup a lock has failed - back out
62 the locks we did get and send an error
63*/
64static void pvfs_lock_async_failed(struct pvfs_state *pvfs,
65 struct ntvfs_request *req,
66 struct pvfs_file *f,
67 struct smb_lock_entry *locks,
68 int i,
69 NTSTATUS status)
70{
71 /* undo the locks we just did */
72 for (i--;i>=0;i--) {
73 brl_unlock(pvfs->brl_context,
74 f->brl_handle,
75 locks[i].pid,
76 locks[i].offset,
77 locks[i].count);
78 f->lock_count--;
79 }
80 req->async_states->status = status;
81 req->async_states->send_fn(req);
82}
83
84
85/*
86 called when we receive a pending lock notification. It means that
87 either our lock timed out or someone else has unlocked a overlapping
88 range, so we should try the lock again. Note that on timeout we
89 do retry the lock, giving it a last chance.
90*/
91static void pvfs_pending_lock_continue(void *private_data, enum pvfs_wait_notice reason)
92{
93 struct pvfs_pending_lock *pending = talloc_get_type(private_data,
94 struct pvfs_pending_lock);
95 struct pvfs_state *pvfs = pending->pvfs;
96 struct pvfs_file *f = pending->f;
97 struct ntvfs_request *req = pending->req;
98 union smb_lock *lck = pending->lck;
99 struct smb_lock_entry *locks;
100 enum brl_type rw;
101 NTSTATUS status;
102 int i;
103 bool timed_out;
104
105 timed_out = (reason != PVFS_WAIT_EVENT);
106
107 locks = lck->lockx.in.locks + lck->lockx.in.ulock_cnt;
108
109 if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) {
110 rw = READ_LOCK;
111 } else {
112 rw = WRITE_LOCK;
113 }
114
115 DLIST_REMOVE(f->pending_list, pending);
116
117 /* we don't retry on a cancel */
118 if (reason == PVFS_WAIT_CANCEL) {
119 if (pvfs->ntvfs->ctx->protocol != PROTOCOL_SMB2) {
120 status = NT_STATUS_FILE_LOCK_CONFLICT;
121 } else {
122 status = NT_STATUS_CANCELLED;
123 }
124 } else {
125 /*
126 * here it's important to pass the pending pointer
127 * because with this we'll get the correct error code
128 * FILE_LOCK_CONFLICT in the error case
129 */
130 status = brl_lock(pvfs->brl_context,
131 f->brl_handle,
132 locks[pending->pending_lock].pid,
133 locks[pending->pending_lock].offset,
134 locks[pending->pending_lock].count,
135 rw, pending);
136 }
137 if (NT_STATUS_IS_OK(status)) {
138 f->lock_count++;
139 timed_out = false;
140 }
141
142 /* if we have failed and timed out, or succeeded, then we
143 don't need the pending lock any more */
144 if (NT_STATUS_IS_OK(status) || timed_out) {
145 NTSTATUS status2;
146 status2 = brl_remove_pending(pvfs->brl_context,
147 f->brl_handle, pending);
148 if (!NT_STATUS_IS_OK(status2)) {
149 DEBUG(0,("pvfs_lock: failed to remove pending lock - %s\n", nt_errstr(status2)));
150 }
151 talloc_free(pending->wait_handle);
152 }
153
154 if (!NT_STATUS_IS_OK(status)) {
155 if (timed_out) {
156 /* no more chances */
157 pvfs_lock_async_failed(pvfs, req, f, locks, pending->pending_lock, status);
158 talloc_free(pending);
159 } else {
160 /* we can try again */
161 DLIST_ADD(f->pending_list, pending);
162 }
163 return;
164 }
165
166 /* if we haven't timed out yet, then we can do more pending locks */
167 if (rw == READ_LOCK) {
168 rw = PENDING_READ_LOCK;
169 } else {
170 rw = PENDING_WRITE_LOCK;
171 }
172
173 /* we've now got the pending lock. try and get the rest, which might
174 lead to more pending locks */
175 for (i=pending->pending_lock+1;i<lck->lockx.in.lock_cnt;i++) {
176 if (pending) {
177 pending->pending_lock = i;
178 }
179
180 status = brl_lock(pvfs->brl_context,
181 f->brl_handle,
182 locks[i].pid,
183 locks[i].offset,
184 locks[i].count,
185 rw, pending);
186 if (!NT_STATUS_IS_OK(status)) {
187 if (pending) {
188 /* a timed lock failed - setup a wait message to handle
189 the pending lock notification or a timeout */
190 pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY,
191 pending->end_time,
192 pvfs_pending_lock_continue,
193 pending);
194 if (pending->wait_handle == NULL) {
195 pvfs_lock_async_failed(pvfs, req, f, locks, i, NT_STATUS_NO_MEMORY);
196 talloc_free(pending);
197 } else {
198 talloc_steal(pending, pending->wait_handle);
199 DLIST_ADD(f->pending_list, pending);
200 }
201 return;
202 }
203 pvfs_lock_async_failed(pvfs, req, f, locks, i, status);
204 talloc_free(pending);
205 return;
206 }
207
208 f->lock_count++;
209 }
210
211 /* we've managed to get all the locks. Tell the client */
212 req->async_states->status = NT_STATUS_OK;
213 req->async_states->send_fn(req);
214 talloc_free(pending);
215}
216
217
218/*
219 called when we close a file that might have locks
220*/
221void pvfs_lock_close(struct pvfs_state *pvfs, struct pvfs_file *f)
222{
223 struct pvfs_pending_lock *p, *next;
224
225 if (f->lock_count || f->pending_list) {
226 DEBUG(5,("pvfs_lock: removing %.0f locks on close\n",
227 (double)f->lock_count));
228 brl_close(f->pvfs->brl_context, f->brl_handle);
229 f->lock_count = 0;
230 }
231
232 /* reply to all the pending lock requests, telling them the
233 lock failed */
234 for (p=f->pending_list;p;p=next) {
235 next = p->next;
236 DLIST_REMOVE(f->pending_list, p);
237 p->req->async_states->status = NT_STATUS_RANGE_NOT_LOCKED;
238 p->req->async_states->send_fn(p->req);
239 }
240}
241
242
243/*
244 cancel a set of locks
245*/
246static NTSTATUS pvfs_lock_cancel(struct pvfs_state *pvfs, struct ntvfs_request *req, union smb_lock *lck,
247 struct pvfs_file *f)
248{
249 struct pvfs_pending_lock *p;
250
251 for (p=f->pending_list;p;p=p->next) {
252 /* check if the lock request matches exactly - you can only cancel with exact matches */
253 if (p->lck->lockx.in.ulock_cnt == lck->lockx.in.ulock_cnt &&
254 p->lck->lockx.in.lock_cnt == lck->lockx.in.lock_cnt &&
255 p->lck->lockx.in.file.ntvfs== lck->lockx.in.file.ntvfs &&
256 p->lck->lockx.in.mode == (lck->lockx.in.mode & ~LOCKING_ANDX_CANCEL_LOCK)) {
257 int i;
258
259 for (i=0;i<lck->lockx.in.ulock_cnt + lck->lockx.in.lock_cnt;i++) {
260 if (p->lck->lockx.in.locks[i].pid != lck->lockx.in.locks[i].pid ||
261 p->lck->lockx.in.locks[i].offset != lck->lockx.in.locks[i].offset ||
262 p->lck->lockx.in.locks[i].count != lck->lockx.in.locks[i].count) {
263 break;
264 }
265 }
266 if (i < lck->lockx.in.ulock_cnt) continue;
267
268 /* an exact match! we can cancel it, which is equivalent
269 to triggering the timeout early */
270 pvfs_pending_lock_continue(p, PVFS_WAIT_TIMEOUT);
271 return NT_STATUS_OK;
272 }
273 }
274
275 return NT_STATUS_DOS(ERRDOS, ERRcancelviolation);
276}
277
278
279/*
280 lock or unlock a byte range
281*/
282NTSTATUS pvfs_lock(struct ntvfs_module_context *ntvfs,
283 struct ntvfs_request *req, union smb_lock *lck)
284{
285 struct pvfs_state *pvfs = talloc_get_type(ntvfs->private_data,
286 struct pvfs_state);
287 struct pvfs_file *f;
288 struct smb_lock_entry *locks;
289 int i;
290 enum brl_type rw;
291 struct pvfs_pending_lock *pending = NULL;
292 NTSTATUS status;
293
294 if (lck->generic.level != RAW_LOCK_GENERIC) {
295 return ntvfs_map_lock(ntvfs, req, lck);
296 }
297
298 if (lck->lockx.in.mode & LOCKING_ANDX_OPLOCK_RELEASE) {
299 return pvfs_oplock_release(ntvfs, req, lck);
300 }
301
302 f = pvfs_find_fd(pvfs, req, lck->lockx.in.file.ntvfs);
303 if (!f) {
304 return NT_STATUS_INVALID_HANDLE;
305 }
306
307 if (f->handle->fd == -1) {
308 return NT_STATUS_FILE_IS_A_DIRECTORY;
309 }
310
311 status = pvfs_break_level2_oplocks(f);
312 NT_STATUS_NOT_OK_RETURN(status);
313
314 if (lck->lockx.in.timeout != 0 &&
315 (req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
316 pending = talloc(f, struct pvfs_pending_lock);
317 if (pending == NULL) {
318 return NT_STATUS_NO_MEMORY;
319 }
320
321 pending->pvfs = pvfs;
322 pending->lck = lck;
323 pending->f = f;
324 pending->req = req;
325
326 pending->end_time =
327 timeval_current_ofs(lck->lockx.in.timeout/1000,
328 1000*(lck->lockx.in.timeout%1000));
329 }
330
331 if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) {
332 rw = pending? PENDING_READ_LOCK : READ_LOCK;
333 } else {
334 rw = pending? PENDING_WRITE_LOCK : WRITE_LOCK;
335 }
336
337 if (lck->lockx.in.mode & LOCKING_ANDX_CANCEL_LOCK) {
338 talloc_free(pending);
339 return pvfs_lock_cancel(pvfs, req, lck, f);
340 }
341
342 if (lck->lockx.in.mode & LOCKING_ANDX_CHANGE_LOCKTYPE) {
343 /* this seems to not be supported by any windows server,
344 or used by any clients */
345 talloc_free(pending);
346 return NT_STATUS_DOS(ERRDOS, ERRnoatomiclocks);
347 }
348
349 /* the unlocks happen first */
350 locks = lck->lockx.in.locks;
351
352 for (i=0;i<lck->lockx.in.ulock_cnt;i++) {
353 status = brl_unlock(pvfs->brl_context,
354 f->brl_handle,
355 locks[i].pid,
356 locks[i].offset,
357 locks[i].count);
358 if (!NT_STATUS_IS_OK(status)) {
359 talloc_free(pending);
360 return status;
361 }
362 f->lock_count--;
363 }
364
365 locks += i;
366
367 for (i=0;i<lck->lockx.in.lock_cnt;i++) {
368 if (pending) {
369 pending->pending_lock = i;
370 }
371
372 status = brl_lock(pvfs->brl_context,
373 f->brl_handle,
374 locks[i].pid,
375 locks[i].offset,
376 locks[i].count,
377 rw, pending);
378 if (!NT_STATUS_IS_OK(status)) {
379 if (pending) {
380 /* a timed lock failed - setup a wait message to handle
381 the pending lock notification or a timeout */
382 pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY,
383 pending->end_time,
384 pvfs_pending_lock_continue,
385 pending);
386 if (pending->wait_handle == NULL) {
387 talloc_free(pending);
388 return NT_STATUS_NO_MEMORY;
389 }
390 talloc_steal(pending, pending->wait_handle);
391 DLIST_ADD(f->pending_list, pending);
392 return NT_STATUS_OK;
393 }
394
395 /* undo the locks we just did */
396 for (i--;i>=0;i--) {
397 brl_unlock(pvfs->brl_context,
398 f->brl_handle,
399 locks[i].pid,
400 locks[i].offset,
401 locks[i].count);
402 f->lock_count--;
403 }
404 talloc_free(pending);
405 return status;
406 }
407 f->lock_count++;
408 }
409
410 talloc_free(pending);
411 return NT_STATUS_OK;
412}
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