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This client driver allows you to use a GPIO pin as a source for PPS
[linux-2.6/next.git] / fs / dlm / user.c
blobb38b122c2f522257fa351e58994f19a4d7c57427
1 /*
2 * Copyright (C) 2006-2010 Red Hat, Inc. All rights reserved.
3 *
4 * This copyrighted material is made available to anyone wishing to use,
5 * modify, copy, or redistribute it subject to the terms and conditions
6 * of the GNU General Public License v.2.
7 */
8
9 #include <linux/miscdevice.h>
10 #include <linux/init.h>
11 #include <linux/wait.h>
12 #include <linux/module.h>
13 #include <linux/file.h>
14 #include <linux/fs.h>
15 #include <linux/poll.h>
16 #include <linux/signal.h>
17 #include <linux/spinlock.h>
18 #include <linux/dlm.h>
19 #include <linux/dlm_device.h>
20 #include <linux/slab.h>
21
22 #include "dlm_internal.h"
23 #include "lockspace.h"
24 #include "lock.h"
25 #include "lvb_table.h"
26 #include "user.h"
27 #include "ast.h"
28
29 static const char name_prefix[] = "dlm";
30 static const struct file_operations device_fops;
31 static atomic_t dlm_monitor_opened;
32 static int dlm_monitor_unused = 1;
33
34 #ifdef CONFIG_COMPAT
35
36 struct dlm_lock_params32 {
37 __u8 mode;
38 __u8 namelen;
39 __u16 unused;
40 __u32 flags;
41 __u32 lkid;
42 __u32 parent;
43 __u64 xid;
44 __u64 timeout;
45 __u32 castparam;
46 __u32 castaddr;
47 __u32 bastparam;
48 __u32 bastaddr;
49 __u32 lksb;
50 char lvb[DLM_USER_LVB_LEN];
51 char name[0];
52 };
53
54 struct dlm_write_request32 {
55 __u32 version[3];
56 __u8 cmd;
57 __u8 is64bit;
58 __u8 unused[2];
59
60 union {
61 struct dlm_lock_params32 lock;
62 struct dlm_lspace_params lspace;
63 struct dlm_purge_params purge;
64 } i;
65 };
66
67 struct dlm_lksb32 {
68 __u32 sb_status;
69 __u32 sb_lkid;
70 __u8 sb_flags;
71 __u32 sb_lvbptr;
72 };
73
74 struct dlm_lock_result32 {
75 __u32 version[3];
76 __u32 length;
77 __u32 user_astaddr;
78 __u32 user_astparam;
79 __u32 user_lksb;
80 struct dlm_lksb32 lksb;
81 __u8 bast_mode;
82 __u8 unused[3];
83 /* Offsets may be zero if no data is present */
84 __u32 lvb_offset;
85 };
86
87 static void compat_input(struct dlm_write_request *kb,
88 struct dlm_write_request32 *kb32,
89 int namelen)
90 {
91 kb->version[0] = kb32->version[0];
92 kb->version[1] = kb32->version[1];
93 kb->version[2] = kb32->version[2];
94
95 kb->cmd = kb32->cmd;
96 kb->is64bit = kb32->is64bit;
97 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
98 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
99 kb->i.lspace.flags = kb32->i.lspace.flags;
100 kb->i.lspace.minor = kb32->i.lspace.minor;
101 memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
102 } else if (kb->cmd == DLM_USER_PURGE) {
103 kb->i.purge.nodeid = kb32->i.purge.nodeid;
104 kb->i.purge.pid = kb32->i.purge.pid;
105 } else {
106 kb->i.lock.mode = kb32->i.lock.mode;
107 kb->i.lock.namelen = kb32->i.lock.namelen;
108 kb->i.lock.flags = kb32->i.lock.flags;
109 kb->i.lock.lkid = kb32->i.lock.lkid;
110 kb->i.lock.parent = kb32->i.lock.parent;
111 kb->i.lock.xid = kb32->i.lock.xid;
112 kb->i.lock.timeout = kb32->i.lock.timeout;
113 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
114 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
115 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
116 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
117 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
118 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
119 memcpy(kb->i.lock.name, kb32->i.lock.name, namelen);
120 }
121 }
122
123 static void compat_output(struct dlm_lock_result *res,
124 struct dlm_lock_result32 *res32)
125 {
126 res32->version[0] = res->version[0];
127 res32->version[1] = res->version[1];
128 res32->version[2] = res->version[2];
129
130 res32->user_astaddr = (__u32)(long)res->user_astaddr;
131 res32->user_astparam = (__u32)(long)res->user_astparam;
132 res32->user_lksb = (__u32)(long)res->user_lksb;
133 res32->bast_mode = res->bast_mode;
134
135 res32->lvb_offset = res->lvb_offset;
136 res32->length = res->length;
137
138 res32->lksb.sb_status = res->lksb.sb_status;
139 res32->lksb.sb_flags = res->lksb.sb_flags;
140 res32->lksb.sb_lkid = res->lksb.sb_lkid;
141 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
142 }
143 #endif
144
145 /* Figure out if this lock is at the end of its life and no longer
146 available for the application to use. The lkb still exists until
147 the final ast is read. A lock becomes EOL in three situations:
148 1. a noqueue request fails with EAGAIN
149 2. an unlock completes with EUNLOCK
150 3. a cancel of a waiting request completes with ECANCEL/EDEADLK
151 An EOL lock needs to be removed from the process's list of locks.
152 And we can't allow any new operation on an EOL lock. This is
153 not related to the lifetime of the lkb struct which is managed
154 entirely by refcount. */
155
156 static int lkb_is_endoflife(int mode, int status)
157 {
158 switch (status) {
159 case -DLM_EUNLOCK:
160 return 1;
161 case -DLM_ECANCEL:
162 case -ETIMEDOUT:
163 case -EDEADLK:
164 case -EAGAIN:
165 if (mode == DLM_LOCK_IV)
166 return 1;
167 break;
168 }
169 return 0;
170 }
171
172 /* we could possibly check if the cancel of an orphan has resulted in the lkb
173 being removed and then remove that lkb from the orphans list and free it */
174
175 void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode,
176 int status, uint32_t sbflags, uint64_t seq)
177 {
178 struct dlm_ls *ls;
179 struct dlm_user_args *ua;
180 struct dlm_user_proc *proc;
181 int rv;
182
183 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
184 return;
185
186 ls = lkb->lkb_resource->res_ls;
187 mutex_lock(&ls->ls_clear_proc_locks);
188
189 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
190 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed
191 lkb->ua so we can't try to use it. This second check is necessary
192 for cases where a completion ast is received for an operation that
193 began before clear_proc_locks did its cancel/unlock. */
194
195 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
196 goto out;
197
198 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
199 ua = lkb->lkb_ua;
200 proc = ua->proc;
201
202 if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL)
203 goto out;
204
205 if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status))
206 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
207
208 spin_lock(&proc->asts_spin);
209
210 rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq);
211 if (rv < 0) {
212 spin_unlock(&proc->asts_spin);
213 goto out;
214 }
215
216 if (list_empty(&lkb->lkb_cb_list)) {
217 kref_get(&lkb->lkb_ref);
218 list_add_tail(&lkb->lkb_cb_list, &proc->asts);
219 wake_up_interruptible(&proc->wait);
220 }
221 spin_unlock(&proc->asts_spin);
222
223 if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) {
224 /* N.B. spin_lock locks_spin, not asts_spin */
225 spin_lock(&proc->locks_spin);
226 if (!list_empty(&lkb->lkb_ownqueue)) {
227 list_del_init(&lkb->lkb_ownqueue);
228 dlm_put_lkb(lkb);
229 }
230 spin_unlock(&proc->locks_spin);
231 }
232 out:
233 mutex_unlock(&ls->ls_clear_proc_locks);
234 }
235
236 static int device_user_lock(struct dlm_user_proc *proc,
237 struct dlm_lock_params *params)
238 {
239 struct dlm_ls *ls;
240 struct dlm_user_args *ua;
241 int error = -ENOMEM;
242
243 ls = dlm_find_lockspace_local(proc->lockspace);
244 if (!ls)
245 return -ENOENT;
246
247 if (!params->castaddr || !params->lksb) {
248 error = -EINVAL;
249 goto out;
250 }
251
252 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
253 if (!ua)
254 goto out;
255 ua->proc = proc;
256 ua->user_lksb = params->lksb;
257 ua->castparam = params->castparam;
258 ua->castaddr = params->castaddr;
259 ua->bastparam = params->bastparam;
260 ua->bastaddr = params->bastaddr;
261 ua->xid = params->xid;
262
263 if (params->flags & DLM_LKF_CONVERT)
264 error = dlm_user_convert(ls, ua,
265 params->mode, params->flags,
266 params->lkid, params->lvb,
267 (unsigned long) params->timeout);
268 else {
269 error = dlm_user_request(ls, ua,
270 params->mode, params->flags,
271 params->name, params->namelen,
272 (unsigned long) params->timeout);
273 if (!error)
274 error = ua->lksb.sb_lkid;
275 }
276 out:
277 dlm_put_lockspace(ls);
278 return error;
279 }
280
281 static int device_user_unlock(struct dlm_user_proc *proc,
282 struct dlm_lock_params *params)
283 {
284 struct dlm_ls *ls;
285 struct dlm_user_args *ua;
286 int error = -ENOMEM;
287
288 ls = dlm_find_lockspace_local(proc->lockspace);
289 if (!ls)
290 return -ENOENT;
291
292 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
293 if (!ua)
294 goto out;
295 ua->proc = proc;
296 ua->user_lksb = params->lksb;
297 ua->castparam = params->castparam;
298 ua->castaddr = params->castaddr;
299
300 if (params->flags & DLM_LKF_CANCEL)
301 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
302 else
303 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
304 params->lvb);
305 out:
306 dlm_put_lockspace(ls);
307 return error;
308 }
309
310 static int device_user_deadlock(struct dlm_user_proc *proc,
311 struct dlm_lock_params *params)
312 {
313 struct dlm_ls *ls;
314 int error;
315
316 ls = dlm_find_lockspace_local(proc->lockspace);
317 if (!ls)
318 return -ENOENT;
319
320 error = dlm_user_deadlock(ls, params->flags, params->lkid);
321
322 dlm_put_lockspace(ls);
323 return error;
324 }
325
326 static int dlm_device_register(struct dlm_ls *ls, char *name)
327 {
328 int error, len;
329
330 /* The device is already registered. This happens when the
331 lockspace is created multiple times from userspace. */
332 if (ls->ls_device.name)
333 return 0;
334
335 error = -ENOMEM;
336 len = strlen(name) + strlen(name_prefix) + 2;
337 ls->ls_device.name = kzalloc(len, GFP_NOFS);
338 if (!ls->ls_device.name)
339 goto fail;
340
341 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
342 name);
343 ls->ls_device.fops = &device_fops;
344 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
345
346 error = misc_register(&ls->ls_device);
347 if (error) {
348 kfree(ls->ls_device.name);
349 }
350 fail:
351 return error;
352 }
353
354 int dlm_device_deregister(struct dlm_ls *ls)
355 {
356 int error;
357
358 /* The device is not registered. This happens when the lockspace
359 was never used from userspace, or when device_create_lockspace()
360 calls dlm_release_lockspace() after the register fails. */
361 if (!ls->ls_device.name)
362 return 0;
363
364 error = misc_deregister(&ls->ls_device);
365 if (!error)
366 kfree(ls->ls_device.name);
367 return error;
368 }
369
370 static int device_user_purge(struct dlm_user_proc *proc,
371 struct dlm_purge_params *params)
372 {
373 struct dlm_ls *ls;
374 int error;
375
376 ls = dlm_find_lockspace_local(proc->lockspace);
377 if (!ls)
378 return -ENOENT;
379
380 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
381
382 dlm_put_lockspace(ls);
383 return error;
384 }
385
386 static int device_create_lockspace(struct dlm_lspace_params *params)
387 {
388 dlm_lockspace_t *lockspace;
389 struct dlm_ls *ls;
390 int error;
391
392 if (!capable(CAP_SYS_ADMIN))
393 return -EPERM;
394
395 error = dlm_new_lockspace(params->name, strlen(params->name),
396 &lockspace, params->flags, DLM_USER_LVB_LEN);
397 if (error)
398 return error;
399
400 ls = dlm_find_lockspace_local(lockspace);
401 if (!ls)
402 return -ENOENT;
403
404 error = dlm_device_register(ls, params->name);
405 dlm_put_lockspace(ls);
406
407 if (error)
408 dlm_release_lockspace(lockspace, 0);
409 else
410 error = ls->ls_device.minor;
411
412 return error;
413 }
414
415 static int device_remove_lockspace(struct dlm_lspace_params *params)
416 {
417 dlm_lockspace_t *lockspace;
418 struct dlm_ls *ls;
419 int error, force = 0;
420
421 if (!capable(CAP_SYS_ADMIN))
422 return -EPERM;
423
424 ls = dlm_find_lockspace_device(params->minor);
425 if (!ls)
426 return -ENOENT;
427
428 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
429 force = 2;
430
431 lockspace = ls->ls_local_handle;
432 dlm_put_lockspace(ls);
433
434 /* The final dlm_release_lockspace waits for references to go to
435 zero, so all processes will need to close their device for the
436 ls before the release will proceed. release also calls the
437 device_deregister above. Converting a positive return value
438 from release to zero means that userspace won't know when its
439 release was the final one, but it shouldn't need to know. */
440
441 error = dlm_release_lockspace(lockspace, force);
442 if (error > 0)
443 error = 0;
444 return error;
445 }
446
447 /* Check the user's version matches ours */
448 static int check_version(struct dlm_write_request *req)
449 {
450 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
451 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
452 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
453
454 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
455 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
456 current->comm,
457 task_pid_nr(current),
458 req->version[0],
459 req->version[1],
460 req->version[2],
461 DLM_DEVICE_VERSION_MAJOR,
462 DLM_DEVICE_VERSION_MINOR,
463 DLM_DEVICE_VERSION_PATCH);
464 return -EINVAL;
465 }
466 return 0;
467 }
468
469 /*
470 * device_write
471 *
472 * device_user_lock
473 * dlm_user_request -> request_lock
474 * dlm_user_convert -> convert_lock
475 *
476 * device_user_unlock
477 * dlm_user_unlock -> unlock_lock
478 * dlm_user_cancel -> cancel_lock
479 *
480 * device_create_lockspace
481 * dlm_new_lockspace
482 *
483 * device_remove_lockspace
484 * dlm_release_lockspace
485 */
486
487 /* a write to a lockspace device is a lock or unlock request, a write
488 to the control device is to create/remove a lockspace */
489
490 static ssize_t device_write(struct file *file, const char __user *buf,
491 size_t count, loff_t *ppos)
492 {
493 struct dlm_user_proc *proc = file->private_data;
494 struct dlm_write_request *kbuf;
495 sigset_t tmpsig, allsigs;
496 int error;
497
498 #ifdef CONFIG_COMPAT
499 if (count < sizeof(struct dlm_write_request32))
500 #else
501 if (count < sizeof(struct dlm_write_request))
502 #endif
503 return -EINVAL;
504
505 kbuf = kzalloc(count + 1, GFP_NOFS);
506 if (!kbuf)
507 return -ENOMEM;
508
509 if (copy_from_user(kbuf, buf, count)) {
510 error = -EFAULT;
511 goto out_free;
512 }
513
514 if (check_version(kbuf)) {
515 error = -EBADE;
516 goto out_free;
517 }
518
519 #ifdef CONFIG_COMPAT
520 if (!kbuf->is64bit) {
521 struct dlm_write_request32 *k32buf;
522 int namelen = 0;
523
524 if (count > sizeof(struct dlm_write_request32))
525 namelen = count - sizeof(struct dlm_write_request32);
526
527 k32buf = (struct dlm_write_request32 *)kbuf;
528
529 /* add 1 after namelen so that the name string is terminated */
530 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
531 GFP_NOFS);
532 if (!kbuf) {
533 kfree(k32buf);
534 return -ENOMEM;
535 }
536
537 if (proc)
538 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
539
540 compat_input(kbuf, k32buf, namelen);
541 kfree(k32buf);
542 }
543 #endif
544
545 /* do we really need this? can a write happen after a close? */
546 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
547 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
548 error = -EINVAL;
549 goto out_free;
550 }
551
552 sigfillset(&allsigs);
553 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
554
555 error = -EINVAL;
556
557 switch (kbuf->cmd)
558 {
559 case DLM_USER_LOCK:
560 if (!proc) {
561 log_print("no locking on control device");
562 goto out_sig;
563 }
564 error = device_user_lock(proc, &kbuf->i.lock);
565 break;
566
567 case DLM_USER_UNLOCK:
568 if (!proc) {
569 log_print("no locking on control device");
570 goto out_sig;
571 }
572 error = device_user_unlock(proc, &kbuf->i.lock);
573 break;
574
575 case DLM_USER_DEADLOCK:
576 if (!proc) {
577 log_print("no locking on control device");
578 goto out_sig;
579 }
580 error = device_user_deadlock(proc, &kbuf->i.lock);
581 break;
582
583 case DLM_USER_CREATE_LOCKSPACE:
584 if (proc) {
585 log_print("create/remove only on control device");
586 goto out_sig;
587 }
588 error = device_create_lockspace(&kbuf->i.lspace);
589 break;
590
591 case DLM_USER_REMOVE_LOCKSPACE:
592 if (proc) {
593 log_print("create/remove only on control device");
594 goto out_sig;
595 }
596 error = device_remove_lockspace(&kbuf->i.lspace);
597 break;
598
599 case DLM_USER_PURGE:
600 if (!proc) {
601 log_print("no locking on control device");
602 goto out_sig;
603 }
604 error = device_user_purge(proc, &kbuf->i.purge);
605 break;
606
607 default:
608 log_print("Unknown command passed to DLM device : %d\n",
609 kbuf->cmd);
610 }
611
612 out_sig:
613 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
614 out_free:
615 kfree(kbuf);
616 return error;
617 }
618
619 /* Every process that opens the lockspace device has its own "proc" structure
620 hanging off the open file that's used to keep track of locks owned by the
621 process and asts that need to be delivered to the process. */
622
623 static int device_open(struct inode *inode, struct file *file)
624 {
625 struct dlm_user_proc *proc;
626 struct dlm_ls *ls;
627
628 ls = dlm_find_lockspace_device(iminor(inode));
629 if (!ls)
630 return -ENOENT;
631
632 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
633 if (!proc) {
634 dlm_put_lockspace(ls);
635 return -ENOMEM;
636 }
637
638 proc->lockspace = ls->ls_local_handle;
639 INIT_LIST_HEAD(&proc->asts);
640 INIT_LIST_HEAD(&proc->locks);
641 INIT_LIST_HEAD(&proc->unlocking);
642 spin_lock_init(&proc->asts_spin);
643 spin_lock_init(&proc->locks_spin);
644 init_waitqueue_head(&proc->wait);
645 file->private_data = proc;
646
647 return 0;
648 }
649
650 static int device_close(struct inode *inode, struct file *file)
651 {
652 struct dlm_user_proc *proc = file->private_data;
653 struct dlm_ls *ls;
654 sigset_t tmpsig, allsigs;
655
656 ls = dlm_find_lockspace_local(proc->lockspace);
657 if (!ls)
658 return -ENOENT;
659
660 sigfillset(&allsigs);
661 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
662
663 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
664
665 dlm_clear_proc_locks(ls, proc);
666
667 /* at this point no more lkb's should exist for this lockspace,
668 so there's no chance of dlm_user_add_ast() being called and
669 looking for lkb->ua->proc */
670
671 kfree(proc);
672 file->private_data = NULL;
673
674 dlm_put_lockspace(ls);
675 dlm_put_lockspace(ls); /* for the find in device_open() */
676
677 /* FIXME: AUTOFREE: if this ls is no longer used do
678 device_remove_lockspace() */
679
680 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
681
682 return 0;
683 }
684
685 static int copy_result_to_user(struct dlm_user_args *ua, int compat,
686 uint32_t flags, int mode, int copy_lvb,
687 char __user *buf, size_t count)
688 {
689 #ifdef CONFIG_COMPAT
690 struct dlm_lock_result32 result32;
691 #endif
692 struct dlm_lock_result result;
693 void *resultptr;
694 int error=0;
695 int len;
696 int struct_len;
697
698 memset(&result, 0, sizeof(struct dlm_lock_result));
699 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
700 result.version[1] = DLM_DEVICE_VERSION_MINOR;
701 result.version[2] = DLM_DEVICE_VERSION_PATCH;
702 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
703 result.user_lksb = ua->user_lksb;
704
705 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
706 in a conversion unless the conversion is successful. See code
707 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
708 notes that a new blocking AST address and parameter are set even if
709 the conversion fails, so maybe we should just do that. */
710
711 if (flags & DLM_CB_BAST) {
712 result.user_astaddr = ua->bastaddr;
713 result.user_astparam = ua->bastparam;
714 result.bast_mode = mode;
715 } else {
716 result.user_astaddr = ua->castaddr;
717 result.user_astparam = ua->castparam;
718 }
719
720 #ifdef CONFIG_COMPAT
721 if (compat)
722 len = sizeof(struct dlm_lock_result32);
723 else
724 #endif
725 len = sizeof(struct dlm_lock_result);
726 struct_len = len;
727
728 /* copy lvb to userspace if there is one, it's been updated, and
729 the user buffer has space for it */
730
731 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
732 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
733 DLM_USER_LVB_LEN)) {
734 error = -EFAULT;
735 goto out;
736 }
737
738 result.lvb_offset = len;
739 len += DLM_USER_LVB_LEN;
740 }
741
742 result.length = len;
743 resultptr = &result;
744 #ifdef CONFIG_COMPAT
745 if (compat) {
746 compat_output(&result, &result32);
747 resultptr = &result32;
748 }
749 #endif
750
751 if (copy_to_user(buf, resultptr, struct_len))
752 error = -EFAULT;
753 else
754 error = len;
755 out:
756 return error;
757 }
758
759 static int copy_version_to_user(char __user *buf, size_t count)
760 {
761 struct dlm_device_version ver;
762
763 memset(&ver, 0, sizeof(struct dlm_device_version));
764 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
765 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
766 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
767
768 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
769 return -EFAULT;
770 return sizeof(struct dlm_device_version);
771 }
772
773 /* a read returns a single ast described in a struct dlm_lock_result */
774
775 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
776 loff_t *ppos)
777 {
778 struct dlm_user_proc *proc = file->private_data;
779 struct dlm_lkb *lkb;
780 DECLARE_WAITQUEUE(wait, current);
781 struct dlm_callback cb;
782 int rv, resid, copy_lvb = 0;
783
784 if (count == sizeof(struct dlm_device_version)) {
785 rv = copy_version_to_user(buf, count);
786 return rv;
787 }
788
789 if (!proc) {
790 log_print("non-version read from control device %zu", count);
791 return -EINVAL;
792 }
793
794 #ifdef CONFIG_COMPAT
795 if (count < sizeof(struct dlm_lock_result32))
796 #else
797 if (count < sizeof(struct dlm_lock_result))
798 #endif
799 return -EINVAL;
800
801 try_another:
802
803 /* do we really need this? can a read happen after a close? */
804 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
805 return -EINVAL;
806
807 spin_lock(&proc->asts_spin);
808 if (list_empty(&proc->asts)) {
809 if (file->f_flags & O_NONBLOCK) {
810 spin_unlock(&proc->asts_spin);
811 return -EAGAIN;
812 }
813
814 add_wait_queue(&proc->wait, &wait);
815
816 repeat:
817 set_current_state(TASK_INTERRUPTIBLE);
818 if (list_empty(&proc->asts) && !signal_pending(current)) {
819 spin_unlock(&proc->asts_spin);
820 schedule();
821 spin_lock(&proc->asts_spin);
822 goto repeat;
823 }
824 set_current_state(TASK_RUNNING);
825 remove_wait_queue(&proc->wait, &wait);
826
827 if (signal_pending(current)) {
828 spin_unlock(&proc->asts_spin);
829 return -ERESTARTSYS;
830 }
831 }
832
833 /* if we empty lkb_callbacks, we don't want to unlock the spinlock
834 without removing lkb_cb_list; so empty lkb_cb_list is always
835 consistent with empty lkb_callbacks */
836
837 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
838
839 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
840 if (rv < 0) {
841 /* this shouldn't happen; lkb should have been removed from
842 list when resid was zero */
843 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
844 list_del_init(&lkb->lkb_cb_list);
845 spin_unlock(&proc->asts_spin);
846 /* removes ref for proc->asts, may cause lkb to be freed */
847 dlm_put_lkb(lkb);
848 goto try_another;
849 }
850 if (!resid)
851 list_del_init(&lkb->lkb_cb_list);
852 spin_unlock(&proc->asts_spin);
853
854 if (cb.flags & DLM_CB_SKIP) {
855 /* removes ref for proc->asts, may cause lkb to be freed */
856 if (!resid)
857 dlm_put_lkb(lkb);
858 goto try_another;
859 }
860
861 if (cb.flags & DLM_CB_CAST) {
862 int old_mode, new_mode;
863
864 old_mode = lkb->lkb_last_cast.mode;
865 new_mode = cb.mode;
866
867 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
868 dlm_lvb_operations[old_mode + 1][new_mode + 1])
869 copy_lvb = 1;
870
871 lkb->lkb_lksb->sb_status = cb.sb_status;
872 lkb->lkb_lksb->sb_flags = cb.sb_flags;
873 }
874
875 rv = copy_result_to_user(lkb->lkb_ua,
876 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
877 cb.flags, cb.mode, copy_lvb, buf, count);
878
879 /* removes ref for proc->asts, may cause lkb to be freed */
880 if (!resid)
881 dlm_put_lkb(lkb);
882
883 return rv;
884 }
885
886 static unsigned int device_poll(struct file *file, poll_table *wait)
887 {
888 struct dlm_user_proc *proc = file->private_data;
889
890 poll_wait(file, &proc->wait, wait);
891
892 spin_lock(&proc->asts_spin);
893 if (!list_empty(&proc->asts)) {
894 spin_unlock(&proc->asts_spin);
895 return POLLIN | POLLRDNORM;
896 }
897 spin_unlock(&proc->asts_spin);
898 return 0;
899 }
900
901 int dlm_user_daemon_available(void)
902 {
903 /* dlm_controld hasn't started (or, has started, but not
904 properly populated configfs) */
905
906 if (!dlm_our_nodeid())
907 return 0;
908
909 /* This is to deal with versions of dlm_controld that don't
910 know about the monitor device. We assume that if the
911 dlm_controld was started (above), but the monitor device
912 was never opened, that it's an old version. dlm_controld
913 should open the monitor device before populating configfs. */
914
915 if (dlm_monitor_unused)
916 return 1;
917
918 return atomic_read(&dlm_monitor_opened) ? 1 : 0;
919 }
920
921 static int ctl_device_open(struct inode *inode, struct file *file)
922 {
923 file->private_data = NULL;
924 return 0;
925 }
926
927 static int ctl_device_close(struct inode *inode, struct file *file)
928 {
929 return 0;
930 }
931
932 static int monitor_device_open(struct inode *inode, struct file *file)
933 {
934 atomic_inc(&dlm_monitor_opened);
935 dlm_monitor_unused = 0;
936 return 0;
937 }
938
939 static int monitor_device_close(struct inode *inode, struct file *file)
940 {
941 if (atomic_dec_and_test(&dlm_monitor_opened))
942 dlm_stop_lockspaces();
943 return 0;
944 }
945
946 static const struct file_operations device_fops = {
947 .open = device_open,
948 .release = device_close,
949 .read = device_read,
950 .write = device_write,
951 .poll = device_poll,
952 .owner = THIS_MODULE,
953 .llseek = noop_llseek,
954 };
955
956 static const struct file_operations ctl_device_fops = {
957 .open = ctl_device_open,
958 .release = ctl_device_close,
959 .read = device_read,
960 .write = device_write,
961 .owner = THIS_MODULE,
962 .llseek = noop_llseek,
963 };
964
965 static struct miscdevice ctl_device = {
966 .name = "dlm-control",
967 .fops = &ctl_device_fops,
968 .minor = MISC_DYNAMIC_MINOR,
969 };
970
971 static const struct file_operations monitor_device_fops = {
972 .open = monitor_device_open,
973 .release = monitor_device_close,
974 .owner = THIS_MODULE,
975 .llseek = noop_llseek,
976 };
977
978 static struct miscdevice monitor_device = {
979 .name = "dlm-monitor",
980 .fops = &monitor_device_fops,
981 .minor = MISC_DYNAMIC_MINOR,
982 };
983
984 int __init dlm_user_init(void)
985 {
986 int error;
987
988 atomic_set(&dlm_monitor_opened, 0);
989
990 error = misc_register(&ctl_device);
991 if (error) {
992 log_print("misc_register failed for control device");
993 goto out;
994 }
995
996 error = misc_register(&monitor_device);
997 if (error) {
998 log_print("misc_register failed for monitor device");
999 misc_deregister(&ctl_device);
1000 }
1001 out:
1002 return error;
1003 }
1004
1005 void dlm_user_exit(void)
1006 {
1007 misc_deregister(&ctl_device);
1008 misc_deregister(&monitor_device);
1009 }
1010
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