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mm-only debug patch...
[mmotm.git] / fs / dlm / user.c
blobebce994ab0b717253a0bfa98230c80cefde397d2
1 /*
2 * Copyright (C) 2006-2009 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
21 #include "dlm_internal.h"
22 #include "lockspace.h"
23 #include "lock.h"
24 #include "lvb_table.h"
25 #include "user.h"
26
27 static const char name_prefix[] = "dlm";
28 static const struct file_operations device_fops;
29 static atomic_t dlm_monitor_opened;
30 static int dlm_monitor_unused = 1;
31
32 #ifdef CONFIG_COMPAT
33
34 struct dlm_lock_params32 {
35 __u8 mode;
36 __u8 namelen;
37 __u16 unused;
38 __u32 flags;
39 __u32 lkid;
40 __u32 parent;
41 __u64 xid;
42 __u64 timeout;
43 __u32 castparam;
44 __u32 castaddr;
45 __u32 bastparam;
46 __u32 bastaddr;
47 __u32 lksb;
48 char lvb[DLM_USER_LVB_LEN];
49 char name[0];
50 };
51
52 struct dlm_write_request32 {
53 __u32 version[3];
54 __u8 cmd;
55 __u8 is64bit;
56 __u8 unused[2];
57
58 union {
59 struct dlm_lock_params32 lock;
60 struct dlm_lspace_params lspace;
61 struct dlm_purge_params purge;
62 } i;
63 };
64
65 struct dlm_lksb32 {
66 __u32 sb_status;
67 __u32 sb_lkid;
68 __u8 sb_flags;
69 __u32 sb_lvbptr;
70 };
71
72 struct dlm_lock_result32 {
73 __u32 version[3];
74 __u32 length;
75 __u32 user_astaddr;
76 __u32 user_astparam;
77 __u32 user_lksb;
78 struct dlm_lksb32 lksb;
79 __u8 bast_mode;
80 __u8 unused[3];
81 /* Offsets may be zero if no data is present */
82 __u32 lvb_offset;
83 };
84
85 static void compat_input(struct dlm_write_request *kb,
86 struct dlm_write_request32 *kb32,
87 int namelen)
88 {
89 kb->version[0] = kb32->version[0];
90 kb->version[1] = kb32->version[1];
91 kb->version[2] = kb32->version[2];
92
93 kb->cmd = kb32->cmd;
94 kb->is64bit = kb32->is64bit;
95 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
96 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
97 kb->i.lspace.flags = kb32->i.lspace.flags;
98 kb->i.lspace.minor = kb32->i.lspace.minor;
99 memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
100 } else if (kb->cmd == DLM_USER_PURGE) {
101 kb->i.purge.nodeid = kb32->i.purge.nodeid;
102 kb->i.purge.pid = kb32->i.purge.pid;
103 } else {
104 kb->i.lock.mode = kb32->i.lock.mode;
105 kb->i.lock.namelen = kb32->i.lock.namelen;
106 kb->i.lock.flags = kb32->i.lock.flags;
107 kb->i.lock.lkid = kb32->i.lock.lkid;
108 kb->i.lock.parent = kb32->i.lock.parent;
109 kb->i.lock.xid = kb32->i.lock.xid;
110 kb->i.lock.timeout = kb32->i.lock.timeout;
111 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
112 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
113 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
114 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
115 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
116 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
117 memcpy(kb->i.lock.name, kb32->i.lock.name, namelen);
118 }
119 }
120
121 static void compat_output(struct dlm_lock_result *res,
122 struct dlm_lock_result32 *res32)
123 {
124 res32->version[0] = res->version[0];
125 res32->version[1] = res->version[1];
126 res32->version[2] = res->version[2];
127
128 res32->user_astaddr = (__u32)(long)res->user_astaddr;
129 res32->user_astparam = (__u32)(long)res->user_astparam;
130 res32->user_lksb = (__u32)(long)res->user_lksb;
131 res32->bast_mode = res->bast_mode;
132
133 res32->lvb_offset = res->lvb_offset;
134 res32->length = res->length;
135
136 res32->lksb.sb_status = res->lksb.sb_status;
137 res32->lksb.sb_flags = res->lksb.sb_flags;
138 res32->lksb.sb_lkid = res->lksb.sb_lkid;
139 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
140 }
141 #endif
142
143 /* Figure out if this lock is at the end of its life and no longer
144 available for the application to use. The lkb still exists until
145 the final ast is read. A lock becomes EOL in three situations:
146 1. a noqueue request fails with EAGAIN
147 2. an unlock completes with EUNLOCK
148 3. a cancel of a waiting request completes with ECANCEL/EDEADLK
149 An EOL lock needs to be removed from the process's list of locks.
150 And we can't allow any new operation on an EOL lock. This is
151 not related to the lifetime of the lkb struct which is managed
152 entirely by refcount. */
153
154 static int lkb_is_endoflife(struct dlm_lkb *lkb, int sb_status, int type)
155 {
156 switch (sb_status) {
157 case -DLM_EUNLOCK:
158 return 1;
159 case -DLM_ECANCEL:
160 case -ETIMEDOUT:
161 case -EDEADLK:
162 if (lkb->lkb_grmode == DLM_LOCK_IV)
163 return 1;
164 break;
165 case -EAGAIN:
166 if (type == AST_COMP && lkb->lkb_grmode == DLM_LOCK_IV)
167 return 1;
168 break;
169 }
170 return 0;
171 }
172
173 /* we could possibly check if the cancel of an orphan has resulted in the lkb
174 being removed and then remove that lkb from the orphans list and free it */
175
176 void dlm_user_add_ast(struct dlm_lkb *lkb, int type, int bastmode)
177 {
178 struct dlm_ls *ls;
179 struct dlm_user_args *ua;
180 struct dlm_user_proc *proc;
181 int eol = 0, ast_type;
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 (type == AST_BAST && ua->bastaddr == NULL)
203 goto out;
204
205 spin_lock(&proc->asts_spin);
206
207 ast_type = lkb->lkb_ast_type;
208 lkb->lkb_ast_type |= type;
209 if (bastmode)
210 lkb->lkb_bastmode = bastmode;
211
212 if (!ast_type) {
213 kref_get(&lkb->lkb_ref);
214 list_add_tail(&lkb->lkb_astqueue, &proc->asts);
215 wake_up_interruptible(&proc->wait);
216 }
217 if (type == AST_COMP && (ast_type & AST_COMP))
218 log_debug(ls, "ast overlap %x status %x %x",
219 lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags);
220
221 eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type);
222 if (eol) {
223 lkb->lkb_ast_type &= ~AST_BAST;
224 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
225 }
226
227 /* We want to copy the lvb to userspace when the completion
228 ast is read if the status is 0, the lock has an lvb and
229 lvb_ops says we should. We could probably have set_lvb_lock()
230 set update_user_lvb instead and not need old_mode */
231
232 if ((lkb->lkb_ast_type & AST_COMP) &&
233 (lkb->lkb_lksb->sb_status == 0) &&
234 lkb->lkb_lksb->sb_lvbptr &&
235 dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1])
236 ua->update_user_lvb = 1;
237 else
238 ua->update_user_lvb = 0;
239
240 spin_unlock(&proc->asts_spin);
241
242 if (eol) {
243 spin_lock(&proc->locks_spin);
244 if (!list_empty(&lkb->lkb_ownqueue)) {
245 list_del_init(&lkb->lkb_ownqueue);
246 dlm_put_lkb(lkb);
247 }
248 spin_unlock(&proc->locks_spin);
249 }
250 out:
251 mutex_unlock(&ls->ls_clear_proc_locks);
252 }
253
254 static int device_user_lock(struct dlm_user_proc *proc,
255 struct dlm_lock_params *params)
256 {
257 struct dlm_ls *ls;
258 struct dlm_user_args *ua;
259 int error = -ENOMEM;
260
261 ls = dlm_find_lockspace_local(proc->lockspace);
262 if (!ls)
263 return -ENOENT;
264
265 if (!params->castaddr || !params->lksb) {
266 error = -EINVAL;
267 goto out;
268 }
269
270 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
271 if (!ua)
272 goto out;
273 ua->proc = proc;
274 ua->user_lksb = params->lksb;
275 ua->castparam = params->castparam;
276 ua->castaddr = params->castaddr;
277 ua->bastparam = params->bastparam;
278 ua->bastaddr = params->bastaddr;
279 ua->xid = params->xid;
280
281 if (params->flags & DLM_LKF_CONVERT)
282 error = dlm_user_convert(ls, ua,
283 params->mode, params->flags,
284 params->lkid, params->lvb,
285 (unsigned long) params->timeout);
286 else {
287 error = dlm_user_request(ls, ua,
288 params->mode, params->flags,
289 params->name, params->namelen,
290 (unsigned long) params->timeout);
291 if (!error)
292 error = ua->lksb.sb_lkid;
293 }
294 out:
295 dlm_put_lockspace(ls);
296 return error;
297 }
298
299 static int device_user_unlock(struct dlm_user_proc *proc,
300 struct dlm_lock_params *params)
301 {
302 struct dlm_ls *ls;
303 struct dlm_user_args *ua;
304 int error = -ENOMEM;
305
306 ls = dlm_find_lockspace_local(proc->lockspace);
307 if (!ls)
308 return -ENOENT;
309
310 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
311 if (!ua)
312 goto out;
313 ua->proc = proc;
314 ua->user_lksb = params->lksb;
315 ua->castparam = params->castparam;
316 ua->castaddr = params->castaddr;
317
318 if (params->flags & DLM_LKF_CANCEL)
319 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
320 else
321 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
322 params->lvb);
323 out:
324 dlm_put_lockspace(ls);
325 return error;
326 }
327
328 static int device_user_deadlock(struct dlm_user_proc *proc,
329 struct dlm_lock_params *params)
330 {
331 struct dlm_ls *ls;
332 int error;
333
334 ls = dlm_find_lockspace_local(proc->lockspace);
335 if (!ls)
336 return -ENOENT;
337
338 error = dlm_user_deadlock(ls, params->flags, params->lkid);
339
340 dlm_put_lockspace(ls);
341 return error;
342 }
343
344 static int dlm_device_register(struct dlm_ls *ls, char *name)
345 {
346 int error, len;
347
348 /* The device is already registered. This happens when the
349 lockspace is created multiple times from userspace. */
350 if (ls->ls_device.name)
351 return 0;
352
353 error = -ENOMEM;
354 len = strlen(name) + strlen(name_prefix) + 2;
355 ls->ls_device.name = kzalloc(len, GFP_KERNEL);
356 if (!ls->ls_device.name)
357 goto fail;
358
359 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
360 name);
361 ls->ls_device.fops = &device_fops;
362 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
363
364 error = misc_register(&ls->ls_device);
365 if (error) {
366 kfree(ls->ls_device.name);
367 }
368 fail:
369 return error;
370 }
371
372 int dlm_device_deregister(struct dlm_ls *ls)
373 {
374 int error;
375
376 /* The device is not registered. This happens when the lockspace
377 was never used from userspace, or when device_create_lockspace()
378 calls dlm_release_lockspace() after the register fails. */
379 if (!ls->ls_device.name)
380 return 0;
381
382 error = misc_deregister(&ls->ls_device);
383 if (!error)
384 kfree(ls->ls_device.name);
385 return error;
386 }
387
388 static int device_user_purge(struct dlm_user_proc *proc,
389 struct dlm_purge_params *params)
390 {
391 struct dlm_ls *ls;
392 int error;
393
394 ls = dlm_find_lockspace_local(proc->lockspace);
395 if (!ls)
396 return -ENOENT;
397
398 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
399
400 dlm_put_lockspace(ls);
401 return error;
402 }
403
404 static int device_create_lockspace(struct dlm_lspace_params *params)
405 {
406 dlm_lockspace_t *lockspace;
407 struct dlm_ls *ls;
408 int error;
409
410 if (!capable(CAP_SYS_ADMIN))
411 return -EPERM;
412
413 error = dlm_new_lockspace(params->name, strlen(params->name),
414 &lockspace, params->flags, DLM_USER_LVB_LEN);
415 if (error)
416 return error;
417
418 ls = dlm_find_lockspace_local(lockspace);
419 if (!ls)
420 return -ENOENT;
421
422 error = dlm_device_register(ls, params->name);
423 dlm_put_lockspace(ls);
424
425 if (error)
426 dlm_release_lockspace(lockspace, 0);
427 else
428 error = ls->ls_device.minor;
429
430 return error;
431 }
432
433 static int device_remove_lockspace(struct dlm_lspace_params *params)
434 {
435 dlm_lockspace_t *lockspace;
436 struct dlm_ls *ls;
437 int error, force = 0;
438
439 if (!capable(CAP_SYS_ADMIN))
440 return -EPERM;
441
442 ls = dlm_find_lockspace_device(params->minor);
443 if (!ls)
444 return -ENOENT;
445
446 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
447 force = 2;
448
449 lockspace = ls->ls_local_handle;
450 dlm_put_lockspace(ls);
451
452 /* The final dlm_release_lockspace waits for references to go to
453 zero, so all processes will need to close their device for the
454 ls before the release will proceed. release also calls the
455 device_deregister above. Converting a positive return value
456 from release to zero means that userspace won't know when its
457 release was the final one, but it shouldn't need to know. */
458
459 error = dlm_release_lockspace(lockspace, force);
460 if (error > 0)
461 error = 0;
462 return error;
463 }
464
465 /* Check the user's version matches ours */
466 static int check_version(struct dlm_write_request *req)
467 {
468 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
469 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
470 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
471
472 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
473 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
474 current->comm,
475 task_pid_nr(current),
476 req->version[0],
477 req->version[1],
478 req->version[2],
479 DLM_DEVICE_VERSION_MAJOR,
480 DLM_DEVICE_VERSION_MINOR,
481 DLM_DEVICE_VERSION_PATCH);
482 return -EINVAL;
483 }
484 return 0;
485 }
486
487 /*
488 * device_write
489 *
490 * device_user_lock
491 * dlm_user_request -> request_lock
492 * dlm_user_convert -> convert_lock
493 *
494 * device_user_unlock
495 * dlm_user_unlock -> unlock_lock
496 * dlm_user_cancel -> cancel_lock
497 *
498 * device_create_lockspace
499 * dlm_new_lockspace
500 *
501 * device_remove_lockspace
502 * dlm_release_lockspace
503 */
504
505 /* a write to a lockspace device is a lock or unlock request, a write
506 to the control device is to create/remove a lockspace */
507
508 static ssize_t device_write(struct file *file, const char __user *buf,
509 size_t count, loff_t *ppos)
510 {
511 struct dlm_user_proc *proc = file->private_data;
512 struct dlm_write_request *kbuf;
513 sigset_t tmpsig, allsigs;
514 int error;
515
516 #ifdef CONFIG_COMPAT
517 if (count < sizeof(struct dlm_write_request32))
518 #else
519 if (count < sizeof(struct dlm_write_request))
520 #endif
521 return -EINVAL;
522
523 kbuf = kzalloc(count + 1, GFP_KERNEL);
524 if (!kbuf)
525 return -ENOMEM;
526
527 if (copy_from_user(kbuf, buf, count)) {
528 error = -EFAULT;
529 goto out_free;
530 }
531
532 if (check_version(kbuf)) {
533 error = -EBADE;
534 goto out_free;
535 }
536
537 #ifdef CONFIG_COMPAT
538 if (!kbuf->is64bit) {
539 struct dlm_write_request32 *k32buf;
540 int namelen = 0;
541
542 if (count > sizeof(struct dlm_write_request32))
543 namelen = count - sizeof(struct dlm_write_request32);
544
545 k32buf = (struct dlm_write_request32 *)kbuf;
546
547 /* add 1 after namelen so that the name string is terminated */
548 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
549 GFP_KERNEL);
550 if (!kbuf) {
551 kfree(k32buf);
552 return -ENOMEM;
553 }
554
555 if (proc)
556 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
557
558 compat_input(kbuf, k32buf, namelen);
559 kfree(k32buf);
560 }
561 #endif
562
563 /* do we really need this? can a write happen after a close? */
564 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
565 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
566 error = -EINVAL;
567 goto out_free;
568 }
569
570 sigfillset(&allsigs);
571 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
572
573 error = -EINVAL;
574
575 switch (kbuf->cmd)
576 {
577 case DLM_USER_LOCK:
578 if (!proc) {
579 log_print("no locking on control device");
580 goto out_sig;
581 }
582 error = device_user_lock(proc, &kbuf->i.lock);
583 break;
584
585 case DLM_USER_UNLOCK:
586 if (!proc) {
587 log_print("no locking on control device");
588 goto out_sig;
589 }
590 error = device_user_unlock(proc, &kbuf->i.lock);
591 break;
592
593 case DLM_USER_DEADLOCK:
594 if (!proc) {
595 log_print("no locking on control device");
596 goto out_sig;
597 }
598 error = device_user_deadlock(proc, &kbuf->i.lock);
599 break;
600
601 case DLM_USER_CREATE_LOCKSPACE:
602 if (proc) {
603 log_print("create/remove only on control device");
604 goto out_sig;
605 }
606 error = device_create_lockspace(&kbuf->i.lspace);
607 break;
608
609 case DLM_USER_REMOVE_LOCKSPACE:
610 if (proc) {
611 log_print("create/remove only on control device");
612 goto out_sig;
613 }
614 error = device_remove_lockspace(&kbuf->i.lspace);
615 break;
616
617 case DLM_USER_PURGE:
618 if (!proc) {
619 log_print("no locking on control device");
620 goto out_sig;
621 }
622 error = device_user_purge(proc, &kbuf->i.purge);
623 break;
624
625 default:
626 log_print("Unknown command passed to DLM device : %d\n",
627 kbuf->cmd);
628 }
629
630 out_sig:
631 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
632 recalc_sigpending();
633 out_free:
634 kfree(kbuf);
635 return error;
636 }
637
638 /* Every process that opens the lockspace device has its own "proc" structure
639 hanging off the open file that's used to keep track of locks owned by the
640 process and asts that need to be delivered to the process. */
641
642 static int device_open(struct inode *inode, struct file *file)
643 {
644 struct dlm_user_proc *proc;
645 struct dlm_ls *ls;
646
647 ls = dlm_find_lockspace_device(iminor(inode));
648 if (!ls)
649 return -ENOENT;
650
651 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
652 if (!proc) {
653 dlm_put_lockspace(ls);
654 return -ENOMEM;
655 }
656
657 proc->lockspace = ls->ls_local_handle;
658 INIT_LIST_HEAD(&proc->asts);
659 INIT_LIST_HEAD(&proc->locks);
660 INIT_LIST_HEAD(&proc->unlocking);
661 spin_lock_init(&proc->asts_spin);
662 spin_lock_init(&proc->locks_spin);
663 init_waitqueue_head(&proc->wait);
664 file->private_data = proc;
665
666 return 0;
667 }
668
669 static int device_close(struct inode *inode, struct file *file)
670 {
671 struct dlm_user_proc *proc = file->private_data;
672 struct dlm_ls *ls;
673 sigset_t tmpsig, allsigs;
674
675 ls = dlm_find_lockspace_local(proc->lockspace);
676 if (!ls)
677 return -ENOENT;
678
679 sigfillset(&allsigs);
680 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
681
682 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
683
684 dlm_clear_proc_locks(ls, proc);
685
686 /* at this point no more lkb's should exist for this lockspace,
687 so there's no chance of dlm_user_add_ast() being called and
688 looking for lkb->ua->proc */
689
690 kfree(proc);
691 file->private_data = NULL;
692
693 dlm_put_lockspace(ls);
694 dlm_put_lockspace(ls); /* for the find in device_open() */
695
696 /* FIXME: AUTOFREE: if this ls is no longer used do
697 device_remove_lockspace() */
698
699 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
700 recalc_sigpending();
701
702 return 0;
703 }
704
705 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type,
706 int bmode, char __user *buf, size_t count)
707 {
708 #ifdef CONFIG_COMPAT
709 struct dlm_lock_result32 result32;
710 #endif
711 struct dlm_lock_result result;
712 void *resultptr;
713 int error=0;
714 int len;
715 int struct_len;
716
717 memset(&result, 0, sizeof(struct dlm_lock_result));
718 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
719 result.version[1] = DLM_DEVICE_VERSION_MINOR;
720 result.version[2] = DLM_DEVICE_VERSION_PATCH;
721 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
722 result.user_lksb = ua->user_lksb;
723
724 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
725 in a conversion unless the conversion is successful. See code
726 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
727 notes that a new blocking AST address and parameter are set even if
728 the conversion fails, so maybe we should just do that. */
729
730 if (type == AST_BAST) {
731 result.user_astaddr = ua->bastaddr;
732 result.user_astparam = ua->bastparam;
733 result.bast_mode = bmode;
734 } else {
735 result.user_astaddr = ua->castaddr;
736 result.user_astparam = ua->castparam;
737 }
738
739 #ifdef CONFIG_COMPAT
740 if (compat)
741 len = sizeof(struct dlm_lock_result32);
742 else
743 #endif
744 len = sizeof(struct dlm_lock_result);
745 struct_len = len;
746
747 /* copy lvb to userspace if there is one, it's been updated, and
748 the user buffer has space for it */
749
750 if (ua->update_user_lvb && ua->lksb.sb_lvbptr &&
751 count >= len + DLM_USER_LVB_LEN) {
752 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
753 DLM_USER_LVB_LEN)) {
754 error = -EFAULT;
755 goto out;
756 }
757
758 result.lvb_offset = len;
759 len += DLM_USER_LVB_LEN;
760 }
761
762 result.length = len;
763 resultptr = &result;
764 #ifdef CONFIG_COMPAT
765 if (compat) {
766 compat_output(&result, &result32);
767 resultptr = &result32;
768 }
769 #endif
770
771 if (copy_to_user(buf, resultptr, struct_len))
772 error = -EFAULT;
773 else
774 error = len;
775 out:
776 return error;
777 }
778
779 static int copy_version_to_user(char __user *buf, size_t count)
780 {
781 struct dlm_device_version ver;
782
783 memset(&ver, 0, sizeof(struct dlm_device_version));
784 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
785 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
786 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
787
788 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
789 return -EFAULT;
790 return sizeof(struct dlm_device_version);
791 }
792
793 /* a read returns a single ast described in a struct dlm_lock_result */
794
795 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
796 loff_t *ppos)
797 {
798 struct dlm_user_proc *proc = file->private_data;
799 struct dlm_lkb *lkb;
800 DECLARE_WAITQUEUE(wait, current);
801 int error, type=0, bmode=0, removed = 0;
802
803 if (count == sizeof(struct dlm_device_version)) {
804 error = copy_version_to_user(buf, count);
805 return error;
806 }
807
808 if (!proc) {
809 log_print("non-version read from control device %zu", count);
810 return -EINVAL;
811 }
812
813 #ifdef CONFIG_COMPAT
814 if (count < sizeof(struct dlm_lock_result32))
815 #else
816 if (count < sizeof(struct dlm_lock_result))
817 #endif
818 return -EINVAL;
819
820 /* do we really need this? can a read happen after a close? */
821 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
822 return -EINVAL;
823
824 spin_lock(&proc->asts_spin);
825 if (list_empty(&proc->asts)) {
826 if (file->f_flags & O_NONBLOCK) {
827 spin_unlock(&proc->asts_spin);
828 return -EAGAIN;
829 }
830
831 add_wait_queue(&proc->wait, &wait);
832
833 repeat:
834 set_current_state(TASK_INTERRUPTIBLE);
835 if (list_empty(&proc->asts) && !signal_pending(current)) {
836 spin_unlock(&proc->asts_spin);
837 schedule();
838 spin_lock(&proc->asts_spin);
839 goto repeat;
840 }
841 set_current_state(TASK_RUNNING);
842 remove_wait_queue(&proc->wait, &wait);
843
844 if (signal_pending(current)) {
845 spin_unlock(&proc->asts_spin);
846 return -ERESTARTSYS;
847 }
848 }
849
850 /* there may be both completion and blocking asts to return for
851 the lkb, don't remove lkb from asts list unless no asts remain */
852
853 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue);
854
855 if (lkb->lkb_ast_type & AST_COMP) {
856 lkb->lkb_ast_type &= ~AST_COMP;
857 type = AST_COMP;
858 } else if (lkb->lkb_ast_type & AST_BAST) {
859 lkb->lkb_ast_type &= ~AST_BAST;
860 type = AST_BAST;
861 bmode = lkb->lkb_bastmode;
862 }
863
864 if (!lkb->lkb_ast_type) {
865 list_del(&lkb->lkb_astqueue);
866 removed = 1;
867 }
868 spin_unlock(&proc->asts_spin);
869
870 error = copy_result_to_user(lkb->lkb_ua,
871 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
872 type, bmode, buf, count);
873
874 /* removes reference for the proc->asts lists added by
875 dlm_user_add_ast() and may result in the lkb being freed */
876 if (removed)
877 dlm_put_lkb(lkb);
878
879 return error;
880 }
881
882 static unsigned int device_poll(struct file *file, poll_table *wait)
883 {
884 struct dlm_user_proc *proc = file->private_data;
885
886 poll_wait(file, &proc->wait, wait);
887
888 spin_lock(&proc->asts_spin);
889 if (!list_empty(&proc->asts)) {
890 spin_unlock(&proc->asts_spin);
891 return POLLIN | POLLRDNORM;
892 }
893 spin_unlock(&proc->asts_spin);
894 return 0;
895 }
896
897 int dlm_user_daemon_available(void)
898 {
899 /* dlm_controld hasn't started (or, has started, but not
900 properly populated configfs) */
901
902 if (!dlm_our_nodeid())
903 return 0;
904
905 /* This is to deal with versions of dlm_controld that don't
906 know about the monitor device. We assume that if the
907 dlm_controld was started (above), but the monitor device
908 was never opened, that it's an old version. dlm_controld
909 should open the monitor device before populating configfs. */
910
911 if (dlm_monitor_unused)
912 return 1;
913
914 return atomic_read(&dlm_monitor_opened) ? 1 : 0;
915 }
916
917 static int ctl_device_open(struct inode *inode, struct file *file)
918 {
919 file->private_data = NULL;
920 return 0;
921 }
922
923 static int ctl_device_close(struct inode *inode, struct file *file)
924 {
925 return 0;
926 }
927
928 static int monitor_device_open(struct inode *inode, struct file *file)
929 {
930 atomic_inc(&dlm_monitor_opened);
931 dlm_monitor_unused = 0;
932 return 0;
933 }
934
935 static int monitor_device_close(struct inode *inode, struct file *file)
936 {
937 if (atomic_dec_and_test(&dlm_monitor_opened))
938 dlm_stop_lockspaces();
939 return 0;
940 }
941
942 static const struct file_operations device_fops = {
943 .open = device_open,
944 .release = device_close,
945 .read = device_read,
946 .write = device_write,
947 .poll = device_poll,
948 .owner = THIS_MODULE,
949 };
950
951 static const struct file_operations ctl_device_fops = {
952 .open = ctl_device_open,
953 .release = ctl_device_close,
954 .read = device_read,
955 .write = device_write,
956 .owner = THIS_MODULE,
957 };
958
959 static struct miscdevice ctl_device = {
960 .name = "dlm-control",
961 .fops = &ctl_device_fops,
962 .minor = MISC_DYNAMIC_MINOR,
963 };
964
965 static const struct file_operations monitor_device_fops = {
966 .open = monitor_device_open,
967 .release = monitor_device_close,
968 .owner = THIS_MODULE,
969 };
970
971 static struct miscdevice monitor_device = {
972 .name = "dlm-monitor",
973 .fops = &monitor_device_fops,
974 .minor = MISC_DYNAMIC_MINOR,
975 };
976
977 int __init dlm_user_init(void)
978 {
979 int error;
980
981 atomic_set(&dlm_monitor_opened, 0);
982
983 error = misc_register(&ctl_device);
984 if (error) {
985 log_print("misc_register failed for control device");
986 goto out;
987 }
988
989 error = misc_register(&monitor_device);
990 if (error) {
991 log_print("misc_register failed for monitor device");
992 misc_deregister(&ctl_device);
993 }
994 out:
995 return error;
996 }
997
998 void dlm_user_exit(void)
999 {
1000 misc_deregister(&ctl_device);
1001 misc_deregister(&monitor_device);
1002 }
1003
mm of the moment repository