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nohz: Fix one jiffy count too far in idle cputime
[linux/fpc-iii.git] / fs / dlm / user.c
blobeb4ed9ba3098198e8d1db357db48c8f6e9e2ff34
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, NULL, params->flags,
396 DLM_USER_LVB_LEN, NULL, NULL, NULL,
397 &lockspace);
398 if (error)
399 return error;
400
401 ls = dlm_find_lockspace_local(lockspace);
402 if (!ls)
403 return -ENOENT;
404
405 error = dlm_device_register(ls, params->name);
406 dlm_put_lockspace(ls);
407
408 if (error)
409 dlm_release_lockspace(lockspace, 0);
410 else
411 error = ls->ls_device.minor;
412
413 return error;
414 }
415
416 static int device_remove_lockspace(struct dlm_lspace_params *params)
417 {
418 dlm_lockspace_t *lockspace;
419 struct dlm_ls *ls;
420 int error, force = 0;
421
422 if (!capable(CAP_SYS_ADMIN))
423 return -EPERM;
424
425 ls = dlm_find_lockspace_device(params->minor);
426 if (!ls)
427 return -ENOENT;
428
429 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
430 force = 2;
431
432 lockspace = ls->ls_local_handle;
433 dlm_put_lockspace(ls);
434
435 /* The final dlm_release_lockspace waits for references to go to
436 zero, so all processes will need to close their device for the
437 ls before the release will proceed. release also calls the
438 device_deregister above. Converting a positive return value
439 from release to zero means that userspace won't know when its
440 release was the final one, but it shouldn't need to know. */
441
442 error = dlm_release_lockspace(lockspace, force);
443 if (error > 0)
444 error = 0;
445 return error;
446 }
447
448 /* Check the user's version matches ours */
449 static int check_version(struct dlm_write_request *req)
450 {
451 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
452 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
453 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
454
455 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
456 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
457 current->comm,
458 task_pid_nr(current),
459 req->version[0],
460 req->version[1],
461 req->version[2],
462 DLM_DEVICE_VERSION_MAJOR,
463 DLM_DEVICE_VERSION_MINOR,
464 DLM_DEVICE_VERSION_PATCH);
465 return -EINVAL;
466 }
467 return 0;
468 }
469
470 /*
471 * device_write
472 *
473 * device_user_lock
474 * dlm_user_request -> request_lock
475 * dlm_user_convert -> convert_lock
476 *
477 * device_user_unlock
478 * dlm_user_unlock -> unlock_lock
479 * dlm_user_cancel -> cancel_lock
480 *
481 * device_create_lockspace
482 * dlm_new_lockspace
483 *
484 * device_remove_lockspace
485 * dlm_release_lockspace
486 */
487
488 /* a write to a lockspace device is a lock or unlock request, a write
489 to the control device is to create/remove a lockspace */
490
491 static ssize_t device_write(struct file *file, const char __user *buf,
492 size_t count, loff_t *ppos)
493 {
494 struct dlm_user_proc *proc = file->private_data;
495 struct dlm_write_request *kbuf;
496 sigset_t tmpsig, allsigs;
497 int error;
498
499 #ifdef CONFIG_COMPAT
500 if (count < sizeof(struct dlm_write_request32))
501 #else
502 if (count < sizeof(struct dlm_write_request))
503 #endif
504 return -EINVAL;
505
506 kbuf = kzalloc(count + 1, GFP_NOFS);
507 if (!kbuf)
508 return -ENOMEM;
509
510 if (copy_from_user(kbuf, buf, count)) {
511 error = -EFAULT;
512 goto out_free;
513 }
514
515 if (check_version(kbuf)) {
516 error = -EBADE;
517 goto out_free;
518 }
519
520 #ifdef CONFIG_COMPAT
521 if (!kbuf->is64bit) {
522 struct dlm_write_request32 *k32buf;
523 int namelen = 0;
524
525 if (count > sizeof(struct dlm_write_request32))
526 namelen = count - sizeof(struct dlm_write_request32);
527
528 k32buf = (struct dlm_write_request32 *)kbuf;
529
530 /* add 1 after namelen so that the name string is terminated */
531 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
532 GFP_NOFS);
533 if (!kbuf) {
534 kfree(k32buf);
535 return -ENOMEM;
536 }
537
538 if (proc)
539 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
540
541 compat_input(kbuf, k32buf, namelen);
542 kfree(k32buf);
543 }
544 #endif
545
546 /* do we really need this? can a write happen after a close? */
547 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
548 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
549 error = -EINVAL;
550 goto out_free;
551 }
552
553 sigfillset(&allsigs);
554 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
555
556 error = -EINVAL;
557
558 switch (kbuf->cmd)
559 {
560 case DLM_USER_LOCK:
561 if (!proc) {
562 log_print("no locking on control device");
563 goto out_sig;
564 }
565 error = device_user_lock(proc, &kbuf->i.lock);
566 break;
567
568 case DLM_USER_UNLOCK:
569 if (!proc) {
570 log_print("no locking on control device");
571 goto out_sig;
572 }
573 error = device_user_unlock(proc, &kbuf->i.lock);
574 break;
575
576 case DLM_USER_DEADLOCK:
577 if (!proc) {
578 log_print("no locking on control device");
579 goto out_sig;
580 }
581 error = device_user_deadlock(proc, &kbuf->i.lock);
582 break;
583
584 case DLM_USER_CREATE_LOCKSPACE:
585 if (proc) {
586 log_print("create/remove only on control device");
587 goto out_sig;
588 }
589 error = device_create_lockspace(&kbuf->i.lspace);
590 break;
591
592 case DLM_USER_REMOVE_LOCKSPACE:
593 if (proc) {
594 log_print("create/remove only on control device");
595 goto out_sig;
596 }
597 error = device_remove_lockspace(&kbuf->i.lspace);
598 break;
599
600 case DLM_USER_PURGE:
601 if (!proc) {
602 log_print("no locking on control device");
603 goto out_sig;
604 }
605 error = device_user_purge(proc, &kbuf->i.purge);
606 break;
607
608 default:
609 log_print("Unknown command passed to DLM device : %d\n",
610 kbuf->cmd);
611 }
612
613 out_sig:
614 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
615 out_free:
616 kfree(kbuf);
617 return error;
618 }
619
620 /* Every process that opens the lockspace device has its own "proc" structure
621 hanging off the open file that's used to keep track of locks owned by the
622 process and asts that need to be delivered to the process. */
623
624 static int device_open(struct inode *inode, struct file *file)
625 {
626 struct dlm_user_proc *proc;
627 struct dlm_ls *ls;
628
629 ls = dlm_find_lockspace_device(iminor(inode));
630 if (!ls)
631 return -ENOENT;
632
633 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
634 if (!proc) {
635 dlm_put_lockspace(ls);
636 return -ENOMEM;
637 }
638
639 proc->lockspace = ls->ls_local_handle;
640 INIT_LIST_HEAD(&proc->asts);
641 INIT_LIST_HEAD(&proc->locks);
642 INIT_LIST_HEAD(&proc->unlocking);
643 spin_lock_init(&proc->asts_spin);
644 spin_lock_init(&proc->locks_spin);
645 init_waitqueue_head(&proc->wait);
646 file->private_data = proc;
647
648 return 0;
649 }
650
651 static int device_close(struct inode *inode, struct file *file)
652 {
653 struct dlm_user_proc *proc = file->private_data;
654 struct dlm_ls *ls;
655 sigset_t tmpsig, allsigs;
656
657 ls = dlm_find_lockspace_local(proc->lockspace);
658 if (!ls)
659 return -ENOENT;
660
661 sigfillset(&allsigs);
662 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
663
664 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
665
666 dlm_clear_proc_locks(ls, proc);
667
668 /* at this point no more lkb's should exist for this lockspace,
669 so there's no chance of dlm_user_add_ast() being called and
670 looking for lkb->ua->proc */
671
672 kfree(proc);
673 file->private_data = NULL;
674
675 dlm_put_lockspace(ls);
676 dlm_put_lockspace(ls); /* for the find in device_open() */
677
678 /* FIXME: AUTOFREE: if this ls is no longer used do
679 device_remove_lockspace() */
680
681 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
682 recalc_sigpending();
683
684 return 0;
685 }
686
687 static int copy_result_to_user(struct dlm_user_args *ua, int compat,
688 uint32_t flags, int mode, int copy_lvb,
689 char __user *buf, size_t count)
690 {
691 #ifdef CONFIG_COMPAT
692 struct dlm_lock_result32 result32;
693 #endif
694 struct dlm_lock_result result;
695 void *resultptr;
696 int error=0;
697 int len;
698 int struct_len;
699
700 memset(&result, 0, sizeof(struct dlm_lock_result));
701 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
702 result.version[1] = DLM_DEVICE_VERSION_MINOR;
703 result.version[2] = DLM_DEVICE_VERSION_PATCH;
704 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
705 result.user_lksb = ua->user_lksb;
706
707 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
708 in a conversion unless the conversion is successful. See code
709 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
710 notes that a new blocking AST address and parameter are set even if
711 the conversion fails, so maybe we should just do that. */
712
713 if (flags & DLM_CB_BAST) {
714 result.user_astaddr = ua->bastaddr;
715 result.user_astparam = ua->bastparam;
716 result.bast_mode = mode;
717 } else {
718 result.user_astaddr = ua->castaddr;
719 result.user_astparam = ua->castparam;
720 }
721
722 #ifdef CONFIG_COMPAT
723 if (compat)
724 len = sizeof(struct dlm_lock_result32);
725 else
726 #endif
727 len = sizeof(struct dlm_lock_result);
728 struct_len = len;
729
730 /* copy lvb to userspace if there is one, it's been updated, and
731 the user buffer has space for it */
732
733 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
734 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
735 DLM_USER_LVB_LEN)) {
736 error = -EFAULT;
737 goto out;
738 }
739
740 result.lvb_offset = len;
741 len += DLM_USER_LVB_LEN;
742 }
743
744 result.length = len;
745 resultptr = &result;
746 #ifdef CONFIG_COMPAT
747 if (compat) {
748 compat_output(&result, &result32);
749 resultptr = &result32;
750 }
751 #endif
752
753 if (copy_to_user(buf, resultptr, struct_len))
754 error = -EFAULT;
755 else
756 error = len;
757 out:
758 return error;
759 }
760
761 static int copy_version_to_user(char __user *buf, size_t count)
762 {
763 struct dlm_device_version ver;
764
765 memset(&ver, 0, sizeof(struct dlm_device_version));
766 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
767 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
768 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
769
770 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
771 return -EFAULT;
772 return sizeof(struct dlm_device_version);
773 }
774
775 /* a read returns a single ast described in a struct dlm_lock_result */
776
777 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
778 loff_t *ppos)
779 {
780 struct dlm_user_proc *proc = file->private_data;
781 struct dlm_lkb *lkb;
782 DECLARE_WAITQUEUE(wait, current);
783 struct dlm_callback cb;
784 int rv, resid, copy_lvb = 0;
785
786 if (count == sizeof(struct dlm_device_version)) {
787 rv = copy_version_to_user(buf, count);
788 return rv;
789 }
790
791 if (!proc) {
792 log_print("non-version read from control device %zu", count);
793 return -EINVAL;
794 }
795
796 #ifdef CONFIG_COMPAT
797 if (count < sizeof(struct dlm_lock_result32))
798 #else
799 if (count < sizeof(struct dlm_lock_result))
800 #endif
801 return -EINVAL;
802
803 try_another:
804
805 /* do we really need this? can a read happen after a close? */
806 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
807 return -EINVAL;
808
809 spin_lock(&proc->asts_spin);
810 if (list_empty(&proc->asts)) {
811 if (file->f_flags & O_NONBLOCK) {
812 spin_unlock(&proc->asts_spin);
813 return -EAGAIN;
814 }
815
816 add_wait_queue(&proc->wait, &wait);
817
818 repeat:
819 set_current_state(TASK_INTERRUPTIBLE);
820 if (list_empty(&proc->asts) && !signal_pending(current)) {
821 spin_unlock(&proc->asts_spin);
822 schedule();
823 spin_lock(&proc->asts_spin);
824 goto repeat;
825 }
826 set_current_state(TASK_RUNNING);
827 remove_wait_queue(&proc->wait, &wait);
828
829 if (signal_pending(current)) {
830 spin_unlock(&proc->asts_spin);
831 return -ERESTARTSYS;
832 }
833 }
834
835 /* if we empty lkb_callbacks, we don't want to unlock the spinlock
836 without removing lkb_cb_list; so empty lkb_cb_list is always
837 consistent with empty lkb_callbacks */
838
839 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
840
841 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
842 if (rv < 0) {
843 /* this shouldn't happen; lkb should have been removed from
844 list when resid was zero */
845 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
846 list_del_init(&lkb->lkb_cb_list);
847 spin_unlock(&proc->asts_spin);
848 /* removes ref for proc->asts, may cause lkb to be freed */
849 dlm_put_lkb(lkb);
850 goto try_another;
851 }
852 if (!resid)
853 list_del_init(&lkb->lkb_cb_list);
854 spin_unlock(&proc->asts_spin);
855
856 if (cb.flags & DLM_CB_SKIP) {
857 /* removes ref for proc->asts, may cause lkb to be freed */
858 if (!resid)
859 dlm_put_lkb(lkb);
860 goto try_another;
861 }
862
863 if (cb.flags & DLM_CB_CAST) {
864 int old_mode, new_mode;
865
866 old_mode = lkb->lkb_last_cast.mode;
867 new_mode = cb.mode;
868
869 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
870 dlm_lvb_operations[old_mode + 1][new_mode + 1])
871 copy_lvb = 1;
872
873 lkb->lkb_lksb->sb_status = cb.sb_status;
874 lkb->lkb_lksb->sb_flags = cb.sb_flags;
875 }
876
877 rv = copy_result_to_user(lkb->lkb_ua,
878 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
879 cb.flags, cb.mode, copy_lvb, buf, count);
880
881 /* removes ref for proc->asts, may cause lkb to be freed */
882 if (!resid)
883 dlm_put_lkb(lkb);
884
885 return rv;
886 }
887
888 static unsigned int device_poll(struct file *file, poll_table *wait)
889 {
890 struct dlm_user_proc *proc = file->private_data;
891
892 poll_wait(file, &proc->wait, wait);
893
894 spin_lock(&proc->asts_spin);
895 if (!list_empty(&proc->asts)) {
896 spin_unlock(&proc->asts_spin);
897 return POLLIN | POLLRDNORM;
898 }
899 spin_unlock(&proc->asts_spin);
900 return 0;
901 }
902
903 int dlm_user_daemon_available(void)
904 {
905 /* dlm_controld hasn't started (or, has started, but not
906 properly populated configfs) */
907
908 if (!dlm_our_nodeid())
909 return 0;
910
911 /* This is to deal with versions of dlm_controld that don't
912 know about the monitor device. We assume that if the
913 dlm_controld was started (above), but the monitor device
914 was never opened, that it's an old version. dlm_controld
915 should open the monitor device before populating configfs. */
916
917 if (dlm_monitor_unused)
918 return 1;
919
920 return atomic_read(&dlm_monitor_opened) ? 1 : 0;
921 }
922
923 static int ctl_device_open(struct inode *inode, struct file *file)
924 {
925 file->private_data = NULL;
926 return 0;
927 }
928
929 static int ctl_device_close(struct inode *inode, struct file *file)
930 {
931 return 0;
932 }
933
934 static int monitor_device_open(struct inode *inode, struct file *file)
935 {
936 atomic_inc(&dlm_monitor_opened);
937 dlm_monitor_unused = 0;
938 return 0;
939 }
940
941 static int monitor_device_close(struct inode *inode, struct file *file)
942 {
943 if (atomic_dec_and_test(&dlm_monitor_opened))
944 dlm_stop_lockspaces();
945 return 0;
946 }
947
948 static const struct file_operations device_fops = {
949 .open = device_open,
950 .release = device_close,
951 .read = device_read,
952 .write = device_write,
953 .poll = device_poll,
954 .owner = THIS_MODULE,
955 .llseek = noop_llseek,
956 };
957
958 static const struct file_operations ctl_device_fops = {
959 .open = ctl_device_open,
960 .release = ctl_device_close,
961 .read = device_read,
962 .write = device_write,
963 .owner = THIS_MODULE,
964 .llseek = noop_llseek,
965 };
966
967 static struct miscdevice ctl_device = {
968 .name = "dlm-control",
969 .fops = &ctl_device_fops,
970 .minor = MISC_DYNAMIC_MINOR,
971 };
972
973 static const struct file_operations monitor_device_fops = {
974 .open = monitor_device_open,
975 .release = monitor_device_close,
976 .owner = THIS_MODULE,
977 .llseek = noop_llseek,
978 };
979
980 static struct miscdevice monitor_device = {
981 .name = "dlm-monitor",
982 .fops = &monitor_device_fops,
983 .minor = MISC_DYNAMIC_MINOR,
984 };
985
986 int __init dlm_user_init(void)
987 {
988 int error;
989
990 atomic_set(&dlm_monitor_opened, 0);
991
992 error = misc_register(&ctl_device);
993 if (error) {
994 log_print("misc_register failed for control device");
995 goto out;
996 }
997
998 error = misc_register(&monitor_device);
999 if (error) {
1000 log_print("misc_register failed for monitor device");
1001 misc_deregister(&ctl_device);
1002 }
1003 out:
1004 return error;
1005 }
1006
1007 void dlm_user_exit(void)
1008 {
1009 misc_deregister(&ctl_device);
1010 misc_deregister(&monitor_device);
1011 }
1012
Linux with added FPC-III support