711c924ae3fbf3289b196f7e5e8c931ccfa595d1
[ira/wip.git] / source4 / ntvfs / posix / pvfs_lock.c
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 */
32 NTSTATUS 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 */
49 struct 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 */
64 static 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 */
91 static 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                 status = NT_STATUS_FILE_LOCK_CONFLICT;
120         } else {
121                 /* 
122                  * here it's important to pass the pending pointer
123                  * because with this we'll get the correct error code
124                  * FILE_LOCK_CONFLICT in the error case
125                  */
126                 status = brl_lock(pvfs->brl_context,
127                                   f->brl_handle,
128                                   locks[pending->pending_lock].pid,
129                                   locks[pending->pending_lock].offset,
130                                   locks[pending->pending_lock].count,
131                                   rw, pending);
132         }
133         if (NT_STATUS_IS_OK(status)) {
134                 f->lock_count++;
135                 timed_out = false;
136         }
137
138         /* if we have failed and timed out, or succeeded, then we
139            don't need the pending lock any more */
140         if (NT_STATUS_IS_OK(status) || timed_out) {
141                 NTSTATUS status2;
142                 status2 = brl_remove_pending(pvfs->brl_context, 
143                                              f->brl_handle, pending);
144                 if (!NT_STATUS_IS_OK(status2)) {
145                         DEBUG(0,("pvfs_lock: failed to remove pending lock - %s\n", nt_errstr(status2)));
146                 }
147                 talloc_free(pending->wait_handle);
148         }
149
150         if (!NT_STATUS_IS_OK(status)) {
151                 if (timed_out) {
152                         /* no more chances */
153                         pvfs_lock_async_failed(pvfs, req, f, locks, pending->pending_lock, status);
154                         talloc_free(pending);
155                 } else {
156                         /* we can try again */
157                         DLIST_ADD(f->pending_list, pending);
158                 }
159                 return;
160         }
161
162         /* if we haven't timed out yet, then we can do more pending locks */
163         if (rw == READ_LOCK) {
164                 rw = PENDING_READ_LOCK;
165         } else {
166                 rw = PENDING_WRITE_LOCK;
167         }
168
169         /* we've now got the pending lock. try and get the rest, which might
170            lead to more pending locks */
171         for (i=pending->pending_lock+1;i<lck->lockx.in.lock_cnt;i++) {          
172                 if (pending) {
173                         pending->pending_lock = i;
174                 }
175
176                 status = brl_lock(pvfs->brl_context,
177                                   f->brl_handle,
178                                   locks[i].pid,
179                                   locks[i].offset,
180                                   locks[i].count,
181                                   rw, pending);
182                 if (!NT_STATUS_IS_OK(status)) {
183                         if (pending) {
184                                 /* a timed lock failed - setup a wait message to handle
185                                    the pending lock notification or a timeout */
186                                 pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY, 
187                                                                          pending->end_time,
188                                                                          pvfs_pending_lock_continue,
189                                                                          pending);
190                                 if (pending->wait_handle == NULL) {
191                                         pvfs_lock_async_failed(pvfs, req, f, locks, i, NT_STATUS_NO_MEMORY);
192                                         talloc_free(pending);
193                                 } else {
194                                         talloc_steal(pending, pending->wait_handle);
195                                         DLIST_ADD(f->pending_list, pending);
196                                 }
197                                 return;
198                         }
199                         pvfs_lock_async_failed(pvfs, req, f, locks, i, status);
200                         talloc_free(pending);
201                         return;
202                 }
203
204                 f->lock_count++;
205         }
206
207         /* we've managed to get all the locks. Tell the client */
208         req->async_states->status = NT_STATUS_OK;
209         req->async_states->send_fn(req);
210         talloc_free(pending);
211 }
212
213
214 /*
215   called when we close a file that might have locks
216 */
217 void pvfs_lock_close(struct pvfs_state *pvfs, struct pvfs_file *f)
218 {
219         struct pvfs_pending_lock *p, *next;
220
221         if (f->lock_count || f->pending_list) {
222                 DEBUG(5,("pvfs_lock: removing %.0f locks on close\n", 
223                          (double)f->lock_count));
224                 brl_close(f->pvfs->brl_context, f->brl_handle);
225                 f->lock_count = 0;
226         }
227
228         /* reply to all the pending lock requests, telling them the 
229            lock failed */
230         for (p=f->pending_list;p;p=next) {
231                 next = p->next;
232                 DLIST_REMOVE(f->pending_list, p);
233                 p->req->async_states->status = NT_STATUS_RANGE_NOT_LOCKED;
234                 p->req->async_states->send_fn(p->req);
235         }
236 }
237
238
239 /*
240   cancel a set of locks
241 */
242 static NTSTATUS pvfs_lock_cancel(struct pvfs_state *pvfs, struct ntvfs_request *req, union smb_lock *lck,
243                                  struct pvfs_file *f)
244 {
245         struct pvfs_pending_lock *p;
246
247         for (p=f->pending_list;p;p=p->next) {
248                 /* check if the lock request matches exactly - you can only cancel with exact matches */
249                 if (p->lck->lockx.in.ulock_cnt == lck->lockx.in.ulock_cnt &&
250                     p->lck->lockx.in.lock_cnt  == lck->lockx.in.lock_cnt &&
251                     p->lck->lockx.in.file.ntvfs== lck->lockx.in.file.ntvfs &&
252                     p->lck->lockx.in.mode      == (lck->lockx.in.mode & ~LOCKING_ANDX_CANCEL_LOCK)) {
253                         int i;
254
255                         for (i=0;i<lck->lockx.in.ulock_cnt + lck->lockx.in.lock_cnt;i++) {
256                                 if (p->lck->lockx.in.locks[i].pid != lck->lockx.in.locks[i].pid ||
257                                     p->lck->lockx.in.locks[i].offset != lck->lockx.in.locks[i].offset ||
258                                     p->lck->lockx.in.locks[i].count != lck->lockx.in.locks[i].count) {
259                                         break;
260                                 }
261                         }
262                         if (i < lck->lockx.in.ulock_cnt) continue;
263
264                         /* an exact match! we can cancel it, which is equivalent
265                            to triggering the timeout early */
266                         pvfs_pending_lock_continue(p, PVFS_WAIT_TIMEOUT);
267                         return NT_STATUS_OK;
268                 }
269         }
270
271         return NT_STATUS_DOS(ERRDOS, ERRcancelviolation);
272 }
273
274
275 /*
276   lock or unlock a byte range
277 */
278 NTSTATUS pvfs_lock(struct ntvfs_module_context *ntvfs,
279                    struct ntvfs_request *req, union smb_lock *lck)
280 {
281         struct pvfs_state *pvfs = talloc_get_type(ntvfs->private_data,
282                                   struct pvfs_state);
283         struct pvfs_file *f;
284         struct smb_lock_entry *locks;
285         int i;
286         enum brl_type rw;
287         struct pvfs_pending_lock *pending = NULL;
288         NTSTATUS status;
289
290         if (lck->generic.level != RAW_LOCK_GENERIC) {
291                 return ntvfs_map_lock(ntvfs, req, lck);
292         }
293
294         if (lck->lockx.in.mode & LOCKING_ANDX_OPLOCK_RELEASE) {
295                 return pvfs_oplock_release(ntvfs, req, lck);
296         }
297
298         f = pvfs_find_fd(pvfs, req, lck->lockx.in.file.ntvfs);
299         if (!f) {
300                 return NT_STATUS_INVALID_HANDLE;
301         }
302
303         if (f->handle->fd == -1) {
304                 return NT_STATUS_FILE_IS_A_DIRECTORY;
305         }
306
307         status = pvfs_break_level2_oplocks(f);
308         NT_STATUS_NOT_OK_RETURN(status);
309
310         if (lck->lockx.in.timeout != 0 && 
311             (req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
312                 pending = talloc(f, struct pvfs_pending_lock);
313                 if (pending == NULL) {
314                         return NT_STATUS_NO_MEMORY;
315                 }
316
317                 pending->pvfs = pvfs;
318                 pending->lck = lck;
319                 pending->f = f;
320                 pending->req = req;
321
322                 pending->end_time = 
323                         timeval_current_ofs(lck->lockx.in.timeout/1000,
324                                             1000*(lck->lockx.in.timeout%1000));
325         }
326
327         if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) {
328                 rw = pending? PENDING_READ_LOCK : READ_LOCK;
329         } else {
330                 rw = pending? PENDING_WRITE_LOCK : WRITE_LOCK;
331         }
332
333         if (lck->lockx.in.mode & LOCKING_ANDX_CANCEL_LOCK) {
334                 talloc_free(pending);
335                 return pvfs_lock_cancel(pvfs, req, lck, f);
336         }
337
338         if (lck->lockx.in.mode & LOCKING_ANDX_CHANGE_LOCKTYPE) {
339                 /* this seems to not be supported by any windows server,
340                    or used by any clients */
341                 talloc_free(pending);
342                 return NT_STATUS_DOS(ERRDOS, ERRnoatomiclocks);
343         }
344
345         /* the unlocks happen first */
346         locks = lck->lockx.in.locks;
347
348         for (i=0;i<lck->lockx.in.ulock_cnt;i++) {
349                 status = brl_unlock(pvfs->brl_context,
350                                     f->brl_handle,
351                                     locks[i].pid,
352                                     locks[i].offset,
353                                     locks[i].count);
354                 if (!NT_STATUS_IS_OK(status)) {
355                         talloc_free(pending);
356                         return status;
357                 }
358                 f->lock_count--;
359         }
360
361         locks += i;
362
363         for (i=0;i<lck->lockx.in.lock_cnt;i++) {
364                 if (pending) {
365                         pending->pending_lock = i;
366                 }
367
368                 status = brl_lock(pvfs->brl_context,
369                                   f->brl_handle,
370                                   locks[i].pid,
371                                   locks[i].offset,
372                                   locks[i].count,
373                                   rw, pending);
374                 if (!NT_STATUS_IS_OK(status)) {
375                         if (pending) {
376                                 /* a timed lock failed - setup a wait message to handle
377                                    the pending lock notification or a timeout */
378                                 pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY, 
379                                                                          pending->end_time,
380                                                                          pvfs_pending_lock_continue,
381                                                                          pending);
382                                 if (pending->wait_handle == NULL) {
383                                         talloc_free(pending);
384                                         return NT_STATUS_NO_MEMORY;
385                                 }
386                                 talloc_steal(pending, pending->wait_handle);
387                                 DLIST_ADD(f->pending_list, pending);
388                                 return NT_STATUS_OK;
389                         }
390
391                         /* undo the locks we just did */
392                         for (i--;i>=0;i--) {
393                                 brl_unlock(pvfs->brl_context,
394                                            f->brl_handle,
395                                            locks[i].pid,
396                                            locks[i].offset,
397                                            locks[i].count);
398                                 f->lock_count--;
399                         }
400                         talloc_free(pending);
401                         return status;
402                 }
403                 f->lock_count++;
404         }
405
406         talloc_free(pending);
407         return NT_STATUS_OK;
408 }