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Luca's patch ported
[cbs-scheduler.git] / fs / dlm / user.c
blob065149e84f42ed547961c19477506489d922ac01
1 /*
2 * Copyright (C) 2006-2008 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 size_t count)
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, count -
100 offsetof(struct dlm_write_request32, i.lspace.name));
101 } else if (kb->cmd == DLM_USER_PURGE) {
102 kb->i.purge.nodeid = kb32->i.purge.nodeid;
103 kb->i.purge.pid = kb32->i.purge.pid;
104 } else {
105 kb->i.lock.mode = kb32->i.lock.mode;
106 kb->i.lock.namelen = kb32->i.lock.namelen;
107 kb->i.lock.flags = kb32->i.lock.flags;
108 kb->i.lock.lkid = kb32->i.lock.lkid;
109 kb->i.lock.parent = kb32->i.lock.parent;
110 kb->i.lock.xid = kb32->i.lock.xid;
111 kb->i.lock.timeout = kb32->i.lock.timeout;
112 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
113 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
114 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
115 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
116 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
117 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
118 memcpy(kb->i.lock.name, kb32->i.lock.name, count -
119 offsetof(struct dlm_write_request32, i.lock.name));
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(struct dlm_lkb *lkb, int sb_status, int type)
157 {
158 switch (sb_status) {
159 case -DLM_EUNLOCK:
160 return 1;
161 case -DLM_ECANCEL:
162 case -ETIMEDOUT:
163 case -EDEADLK:
164 if (lkb->lkb_grmode == DLM_LOCK_IV)
165 return 1;
166 break;
167 case -EAGAIN:
168 if (type == AST_COMP && lkb->lkb_grmode == DLM_LOCK_IV)
169 return 1;
170 break;
171 }
172 return 0;
173 }
174
175 /* we could possibly check if the cancel of an orphan has resulted in the lkb
176 being removed and then remove that lkb from the orphans list and free it */
177
178 void dlm_user_add_ast(struct dlm_lkb *lkb, int type, int bastmode)
179 {
180 struct dlm_ls *ls;
181 struct dlm_user_args *ua;
182 struct dlm_user_proc *proc;
183 int eol = 0, ast_type;
184
185 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
186 return;
187
188 ls = lkb->lkb_resource->res_ls;
189 mutex_lock(&ls->ls_clear_proc_locks);
190
191 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
192 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed
193 lkb->ua so we can't try to use it. This second check is necessary
194 for cases where a completion ast is received for an operation that
195 began before clear_proc_locks did its cancel/unlock. */
196
197 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
198 goto out;
199
200 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
201 ua = lkb->lkb_ua;
202 proc = ua->proc;
203
204 if (type == AST_BAST && ua->bastaddr == NULL)
205 goto out;
206
207 spin_lock(&proc->asts_spin);
208
209 ast_type = lkb->lkb_ast_type;
210 lkb->lkb_ast_type |= type;
211 if (bastmode)
212 lkb->lkb_bastmode = bastmode;
213
214 if (!ast_type) {
215 kref_get(&lkb->lkb_ref);
216 list_add_tail(&lkb->lkb_astqueue, &proc->asts);
217 wake_up_interruptible(&proc->wait);
218 }
219 if (type == AST_COMP && (ast_type & AST_COMP))
220 log_debug(ls, "ast overlap %x status %x %x",
221 lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags);
222
223 eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type);
224 if (eol) {
225 lkb->lkb_ast_type &= ~AST_BAST;
226 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
227 }
228
229 /* We want to copy the lvb to userspace when the completion
230 ast is read if the status is 0, the lock has an lvb and
231 lvb_ops says we should. We could probably have set_lvb_lock()
232 set update_user_lvb instead and not need old_mode */
233
234 if ((lkb->lkb_ast_type & AST_COMP) &&
235 (lkb->lkb_lksb->sb_status == 0) &&
236 lkb->lkb_lksb->sb_lvbptr &&
237 dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1])
238 ua->update_user_lvb = 1;
239 else
240 ua->update_user_lvb = 0;
241
242 spin_unlock(&proc->asts_spin);
243
244 if (eol) {
245 spin_lock(&proc->locks_spin);
246 if (!list_empty(&lkb->lkb_ownqueue)) {
247 list_del_init(&lkb->lkb_ownqueue);
248 dlm_put_lkb(lkb);
249 }
250 spin_unlock(&proc->locks_spin);
251 }
252 out:
253 mutex_unlock(&ls->ls_clear_proc_locks);
254 }
255
256 static int device_user_lock(struct dlm_user_proc *proc,
257 struct dlm_lock_params *params)
258 {
259 struct dlm_ls *ls;
260 struct dlm_user_args *ua;
261 int error = -ENOMEM;
262
263 ls = dlm_find_lockspace_local(proc->lockspace);
264 if (!ls)
265 return -ENOENT;
266
267 if (!params->castaddr || !params->lksb) {
268 error = -EINVAL;
269 goto out;
270 }
271
272 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
273 if (!ua)
274 goto out;
275 ua->proc = proc;
276 ua->user_lksb = params->lksb;
277 ua->castparam = params->castparam;
278 ua->castaddr = params->castaddr;
279 ua->bastparam = params->bastparam;
280 ua->bastaddr = params->bastaddr;
281 ua->xid = params->xid;
282
283 if (params->flags & DLM_LKF_CONVERT)
284 error = dlm_user_convert(ls, ua,
285 params->mode, params->flags,
286 params->lkid, params->lvb,
287 (unsigned long) params->timeout);
288 else {
289 error = dlm_user_request(ls, ua,
290 params->mode, params->flags,
291 params->name, params->namelen,
292 (unsigned long) params->timeout);
293 if (!error)
294 error = ua->lksb.sb_lkid;
295 }
296 out:
297 dlm_put_lockspace(ls);
298 return error;
299 }
300
301 static int device_user_unlock(struct dlm_user_proc *proc,
302 struct dlm_lock_params *params)
303 {
304 struct dlm_ls *ls;
305 struct dlm_user_args *ua;
306 int error = -ENOMEM;
307
308 ls = dlm_find_lockspace_local(proc->lockspace);
309 if (!ls)
310 return -ENOENT;
311
312 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
313 if (!ua)
314 goto out;
315 ua->proc = proc;
316 ua->user_lksb = params->lksb;
317 ua->castparam = params->castparam;
318 ua->castaddr = params->castaddr;
319
320 if (params->flags & DLM_LKF_CANCEL)
321 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
322 else
323 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
324 params->lvb);
325 out:
326 dlm_put_lockspace(ls);
327 return error;
328 }
329
330 static int device_user_deadlock(struct dlm_user_proc *proc,
331 struct dlm_lock_params *params)
332 {
333 struct dlm_ls *ls;
334 int error;
335
336 ls = dlm_find_lockspace_local(proc->lockspace);
337 if (!ls)
338 return -ENOENT;
339
340 error = dlm_user_deadlock(ls, params->flags, params->lkid);
341
342 dlm_put_lockspace(ls);
343 return error;
344 }
345
346 static int dlm_device_register(struct dlm_ls *ls, char *name)
347 {
348 int error, len;
349
350 /* The device is already registered. This happens when the
351 lockspace is created multiple times from userspace. */
352 if (ls->ls_device.name)
353 return 0;
354
355 error = -ENOMEM;
356 len = strlen(name) + strlen(name_prefix) + 2;
357 ls->ls_device.name = kzalloc(len, GFP_KERNEL);
358 if (!ls->ls_device.name)
359 goto fail;
360
361 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
362 name);
363 ls->ls_device.fops = &device_fops;
364 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
365
366 error = misc_register(&ls->ls_device);
367 if (error) {
368 kfree(ls->ls_device.name);
369 }
370 fail:
371 return error;
372 }
373
374 int dlm_device_deregister(struct dlm_ls *ls)
375 {
376 int error;
377
378 /* The device is not registered. This happens when the lockspace
379 was never used from userspace, or when device_create_lockspace()
380 calls dlm_release_lockspace() after the register fails. */
381 if (!ls->ls_device.name)
382 return 0;
383
384 error = misc_deregister(&ls->ls_device);
385 if (!error)
386 kfree(ls->ls_device.name);
387 return error;
388 }
389
390 static int device_user_purge(struct dlm_user_proc *proc,
391 struct dlm_purge_params *params)
392 {
393 struct dlm_ls *ls;
394 int error;
395
396 ls = dlm_find_lockspace_local(proc->lockspace);
397 if (!ls)
398 return -ENOENT;
399
400 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
401
402 dlm_put_lockspace(ls);
403 return error;
404 }
405
406 static int device_create_lockspace(struct dlm_lspace_params *params)
407 {
408 dlm_lockspace_t *lockspace;
409 struct dlm_ls *ls;
410 int error;
411
412 if (!capable(CAP_SYS_ADMIN))
413 return -EPERM;
414
415 error = dlm_new_lockspace(params->name, strlen(params->name),
416 &lockspace, params->flags, DLM_USER_LVB_LEN);
417 if (error)
418 return error;
419
420 ls = dlm_find_lockspace_local(lockspace);
421 if (!ls)
422 return -ENOENT;
423
424 error = dlm_device_register(ls, params->name);
425 dlm_put_lockspace(ls);
426
427 if (error)
428 dlm_release_lockspace(lockspace, 0);
429 else
430 error = ls->ls_device.minor;
431
432 return error;
433 }
434
435 static int device_remove_lockspace(struct dlm_lspace_params *params)
436 {
437 dlm_lockspace_t *lockspace;
438 struct dlm_ls *ls;
439 int error, force = 0;
440
441 if (!capable(CAP_SYS_ADMIN))
442 return -EPERM;
443
444 ls = dlm_find_lockspace_device(params->minor);
445 if (!ls)
446 return -ENOENT;
447
448 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
449 force = 2;
450
451 lockspace = ls->ls_local_handle;
452 dlm_put_lockspace(ls);
453
454 /* The final dlm_release_lockspace waits for references to go to
455 zero, so all processes will need to close their device for the
456 ls before the release will proceed. release also calls the
457 device_deregister above. Converting a positive return value
458 from release to zero means that userspace won't know when its
459 release was the final one, but it shouldn't need to know. */
460
461 error = dlm_release_lockspace(lockspace, force);
462 if (error > 0)
463 error = 0;
464 return error;
465 }
466
467 /* Check the user's version matches ours */
468 static int check_version(struct dlm_write_request *req)
469 {
470 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
471 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
472 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
473
474 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
475 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
476 current->comm,
477 task_pid_nr(current),
478 req->version[0],
479 req->version[1],
480 req->version[2],
481 DLM_DEVICE_VERSION_MAJOR,
482 DLM_DEVICE_VERSION_MINOR,
483 DLM_DEVICE_VERSION_PATCH);
484 return -EINVAL;
485 }
486 return 0;
487 }
488
489 /*
490 * device_write
491 *
492 * device_user_lock
493 * dlm_user_request -> request_lock
494 * dlm_user_convert -> convert_lock
495 *
496 * device_user_unlock
497 * dlm_user_unlock -> unlock_lock
498 * dlm_user_cancel -> cancel_lock
499 *
500 * device_create_lockspace
501 * dlm_new_lockspace
502 *
503 * device_remove_lockspace
504 * dlm_release_lockspace
505 */
506
507 /* a write to a lockspace device is a lock or unlock request, a write
508 to the control device is to create/remove a lockspace */
509
510 static ssize_t device_write(struct file *file, const char __user *buf,
511 size_t count, loff_t *ppos)
512 {
513 struct dlm_user_proc *proc = file->private_data;
514 struct dlm_write_request *kbuf;
515 sigset_t tmpsig, allsigs;
516 int error;
517
518 #ifdef CONFIG_COMPAT
519 if (count < sizeof(struct dlm_write_request32))
520 #else
521 if (count < sizeof(struct dlm_write_request))
522 #endif
523 return -EINVAL;
524
525 kbuf = kzalloc(count + 1, GFP_KERNEL);
526 if (!kbuf)
527 return -ENOMEM;
528
529 if (copy_from_user(kbuf, buf, count)) {
530 error = -EFAULT;
531 goto out_free;
532 }
533
534 if (check_version(kbuf)) {
535 error = -EBADE;
536 goto out_free;
537 }
538
539 #ifdef CONFIG_COMPAT
540 if (!kbuf->is64bit) {
541 struct dlm_write_request32 *k32buf;
542 k32buf = (struct dlm_write_request32 *)kbuf;
543 kbuf = kmalloc(count + 1 + (sizeof(struct dlm_write_request) -
544 sizeof(struct dlm_write_request32)), GFP_KERNEL);
545 if (!kbuf) {
546 kfree(k32buf);
547 return -ENOMEM;
548 }
549
550 if (proc)
551 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
552 compat_input(kbuf, k32buf, count + 1);
553 kfree(k32buf);
554 }
555 #endif
556
557 /* do we really need this? can a write happen after a close? */
558 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
559 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
560 error = -EINVAL;
561 goto out_free;
562 }
563
564 sigfillset(&allsigs);
565 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
566
567 error = -EINVAL;
568
569 switch (kbuf->cmd)
570 {
571 case DLM_USER_LOCK:
572 if (!proc) {
573 log_print("no locking on control device");
574 goto out_sig;
575 }
576 error = device_user_lock(proc, &kbuf->i.lock);
577 break;
578
579 case DLM_USER_UNLOCK:
580 if (!proc) {
581 log_print("no locking on control device");
582 goto out_sig;
583 }
584 error = device_user_unlock(proc, &kbuf->i.lock);
585 break;
586
587 case DLM_USER_DEADLOCK:
588 if (!proc) {
589 log_print("no locking on control device");
590 goto out_sig;
591 }
592 error = device_user_deadlock(proc, &kbuf->i.lock);
593 break;
594
595 case DLM_USER_CREATE_LOCKSPACE:
596 if (proc) {
597 log_print("create/remove only on control device");
598 goto out_sig;
599 }
600 error = device_create_lockspace(&kbuf->i.lspace);
601 break;
602
603 case DLM_USER_REMOVE_LOCKSPACE:
604 if (proc) {
605 log_print("create/remove only on control device");
606 goto out_sig;
607 }
608 error = device_remove_lockspace(&kbuf->i.lspace);
609 break;
610
611 case DLM_USER_PURGE:
612 if (!proc) {
613 log_print("no locking on control device");
614 goto out_sig;
615 }
616 error = device_user_purge(proc, &kbuf->i.purge);
617 break;
618
619 default:
620 log_print("Unknown command passed to DLM device : %d\n",
621 kbuf->cmd);
622 }
623
624 out_sig:
625 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
626 recalc_sigpending();
627 out_free:
628 kfree(kbuf);
629 return error;
630 }
631
632 /* Every process that opens the lockspace device has its own "proc" structure
633 hanging off the open file that's used to keep track of locks owned by the
634 process and asts that need to be delivered to the process. */
635
636 static int device_open(struct inode *inode, struct file *file)
637 {
638 struct dlm_user_proc *proc;
639 struct dlm_ls *ls;
640
641 ls = dlm_find_lockspace_device(iminor(inode));
642 if (!ls)
643 return -ENOENT;
644
645 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
646 if (!proc) {
647 dlm_put_lockspace(ls);
648 return -ENOMEM;
649 }
650
651 proc->lockspace = ls->ls_local_handle;
652 INIT_LIST_HEAD(&proc->asts);
653 INIT_LIST_HEAD(&proc->locks);
654 INIT_LIST_HEAD(&proc->unlocking);
655 spin_lock_init(&proc->asts_spin);
656 spin_lock_init(&proc->locks_spin);
657 init_waitqueue_head(&proc->wait);
658 file->private_data = proc;
659
660 return 0;
661 }
662
663 static int device_close(struct inode *inode, struct file *file)
664 {
665 struct dlm_user_proc *proc = file->private_data;
666 struct dlm_ls *ls;
667 sigset_t tmpsig, allsigs;
668
669 ls = dlm_find_lockspace_local(proc->lockspace);
670 if (!ls)
671 return -ENOENT;
672
673 sigfillset(&allsigs);
674 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
675
676 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
677
678 dlm_clear_proc_locks(ls, proc);
679
680 /* at this point no more lkb's should exist for this lockspace,
681 so there's no chance of dlm_user_add_ast() being called and
682 looking for lkb->ua->proc */
683
684 kfree(proc);
685 file->private_data = NULL;
686
687 dlm_put_lockspace(ls);
688 dlm_put_lockspace(ls); /* for the find in device_open() */
689
690 /* FIXME: AUTOFREE: if this ls is no longer used do
691 device_remove_lockspace() */
692
693 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
694 recalc_sigpending();
695
696 return 0;
697 }
698
699 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type,
700 int bmode, char __user *buf, size_t count)
701 {
702 #ifdef CONFIG_COMPAT
703 struct dlm_lock_result32 result32;
704 #endif
705 struct dlm_lock_result result;
706 void *resultptr;
707 int error=0;
708 int len;
709 int struct_len;
710
711 memset(&result, 0, sizeof(struct dlm_lock_result));
712 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
713 result.version[1] = DLM_DEVICE_VERSION_MINOR;
714 result.version[2] = DLM_DEVICE_VERSION_PATCH;
715 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
716 result.user_lksb = ua->user_lksb;
717
718 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
719 in a conversion unless the conversion is successful. See code
720 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
721 notes that a new blocking AST address and parameter are set even if
722 the conversion fails, so maybe we should just do that. */
723
724 if (type == AST_BAST) {
725 result.user_astaddr = ua->bastaddr;
726 result.user_astparam = ua->bastparam;
727 result.bast_mode = bmode;
728 } else {
729 result.user_astaddr = ua->castaddr;
730 result.user_astparam = ua->castparam;
731 }
732
733 #ifdef CONFIG_COMPAT
734 if (compat)
735 len = sizeof(struct dlm_lock_result32);
736 else
737 #endif
738 len = sizeof(struct dlm_lock_result);
739 struct_len = len;
740
741 /* copy lvb to userspace if there is one, it's been updated, and
742 the user buffer has space for it */
743
744 if (ua->update_user_lvb && ua->lksb.sb_lvbptr &&
745 count >= len + DLM_USER_LVB_LEN) {
746 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
747 DLM_USER_LVB_LEN)) {
748 error = -EFAULT;
749 goto out;
750 }
751
752 result.lvb_offset = len;
753 len += DLM_USER_LVB_LEN;
754 }
755
756 result.length = len;
757 resultptr = &result;
758 #ifdef CONFIG_COMPAT
759 if (compat) {
760 compat_output(&result, &result32);
761 resultptr = &result32;
762 }
763 #endif
764
765 if (copy_to_user(buf, resultptr, struct_len))
766 error = -EFAULT;
767 else
768 error = len;
769 out:
770 return error;
771 }
772
773 static int copy_version_to_user(char __user *buf, size_t count)
774 {
775 struct dlm_device_version ver;
776
777 memset(&ver, 0, sizeof(struct dlm_device_version));
778 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
779 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
780 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
781
782 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
783 return -EFAULT;
784 return sizeof(struct dlm_device_version);
785 }
786
787 /* a read returns a single ast described in a struct dlm_lock_result */
788
789 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
790 loff_t *ppos)
791 {
792 struct dlm_user_proc *proc = file->private_data;
793 struct dlm_lkb *lkb;
794 DECLARE_WAITQUEUE(wait, current);
795 int error, type=0, bmode=0, removed = 0;
796
797 if (count == sizeof(struct dlm_device_version)) {
798 error = copy_version_to_user(buf, count);
799 return error;
800 }
801
802 if (!proc) {
803 log_print("non-version read from control device %zu", count);
804 return -EINVAL;
805 }
806
807 #ifdef CONFIG_COMPAT
808 if (count < sizeof(struct dlm_lock_result32))
809 #else
810 if (count < sizeof(struct dlm_lock_result))
811 #endif
812 return -EINVAL;
813
814 /* do we really need this? can a read happen after a close? */
815 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
816 return -EINVAL;
817
818 spin_lock(&proc->asts_spin);
819 if (list_empty(&proc->asts)) {
820 if (file->f_flags & O_NONBLOCK) {
821 spin_unlock(&proc->asts_spin);
822 return -EAGAIN;
823 }
824
825 add_wait_queue(&proc->wait, &wait);
826
827 repeat:
828 set_current_state(TASK_INTERRUPTIBLE);
829 if (list_empty(&proc->asts) && !signal_pending(current)) {
830 spin_unlock(&proc->asts_spin);
831 schedule();
832 spin_lock(&proc->asts_spin);
833 goto repeat;
834 }
835 set_current_state(TASK_RUNNING);
836 remove_wait_queue(&proc->wait, &wait);
837
838 if (signal_pending(current)) {
839 spin_unlock(&proc->asts_spin);
840 return -ERESTARTSYS;
841 }
842 }
843
844 /* there may be both completion and blocking asts to return for
845 the lkb, don't remove lkb from asts list unless no asts remain */
846
847 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue);
848
849 if (lkb->lkb_ast_type & AST_COMP) {
850 lkb->lkb_ast_type &= ~AST_COMP;
851 type = AST_COMP;
852 } else if (lkb->lkb_ast_type & AST_BAST) {
853 lkb->lkb_ast_type &= ~AST_BAST;
854 type = AST_BAST;
855 bmode = lkb->lkb_bastmode;
856 }
857
858 if (!lkb->lkb_ast_type) {
859 list_del(&lkb->lkb_astqueue);
860 removed = 1;
861 }
862 spin_unlock(&proc->asts_spin);
863
864 error = copy_result_to_user(lkb->lkb_ua,
865 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
866 type, bmode, buf, count);
867
868 /* removes reference for the proc->asts lists added by
869 dlm_user_add_ast() and may result in the lkb being freed */
870 if (removed)
871 dlm_put_lkb(lkb);
872
873 return error;
874 }
875
876 static unsigned int device_poll(struct file *file, poll_table *wait)
877 {
878 struct dlm_user_proc *proc = file->private_data;
879
880 poll_wait(file, &proc->wait, wait);
881
882 spin_lock(&proc->asts_spin);
883 if (!list_empty(&proc->asts)) {
884 spin_unlock(&proc->asts_spin);
885 return POLLIN | POLLRDNORM;
886 }
887 spin_unlock(&proc->asts_spin);
888 return 0;
889 }
890
891 int dlm_user_daemon_available(void)
892 {
893 /* dlm_controld hasn't started (or, has started, but not
894 properly populated configfs) */
895
896 if (!dlm_our_nodeid())
897 return 0;
898
899 /* This is to deal with versions of dlm_controld that don't
900 know about the monitor device. We assume that if the
901 dlm_controld was started (above), but the monitor device
902 was never opened, that it's an old version. dlm_controld
903 should open the monitor device before populating configfs. */
904
905 if (dlm_monitor_unused)
906 return 1;
907
908 return atomic_read(&dlm_monitor_opened) ? 1 : 0;
909 }
910
911 static int ctl_device_open(struct inode *inode, struct file *file)
912 {
913 file->private_data = NULL;
914 return 0;
915 }
916
917 static int ctl_device_close(struct inode *inode, struct file *file)
918 {
919 return 0;
920 }
921
922 static int monitor_device_open(struct inode *inode, struct file *file)
923 {
924 atomic_inc(&dlm_monitor_opened);
925 dlm_monitor_unused = 0;
926 return 0;
927 }
928
929 static int monitor_device_close(struct inode *inode, struct file *file)
930 {
931 if (atomic_dec_and_test(&dlm_monitor_opened))
932 dlm_stop_lockspaces();
933 return 0;
934 }
935
936 static const struct file_operations device_fops = {
937 .open = device_open,
938 .release = device_close,
939 .read = device_read,
940 .write = device_write,
941 .poll = device_poll,
942 .owner = THIS_MODULE,
943 };
944
945 static const struct file_operations ctl_device_fops = {
946 .open = ctl_device_open,
947 .release = ctl_device_close,
948 .read = device_read,
949 .write = device_write,
950 .owner = THIS_MODULE,
951 };
952
953 static struct miscdevice ctl_device = {
954 .name = "dlm-control",
955 .fops = &ctl_device_fops,
956 .minor = MISC_DYNAMIC_MINOR,
957 };
958
959 static const struct file_operations monitor_device_fops = {
960 .open = monitor_device_open,
961 .release = monitor_device_close,
962 .owner = THIS_MODULE,
963 };
964
965 static struct miscdevice monitor_device = {
966 .name = "dlm-monitor",
967 .fops = &monitor_device_fops,
968 .minor = MISC_DYNAMIC_MINOR,
969 };
970
971 int __init dlm_user_init(void)
972 {
973 int error;
974
975 atomic_set(&dlm_monitor_opened, 0);
976
977 error = misc_register(&ctl_device);
978 if (error) {
979 log_print("misc_register failed for control device");
980 goto out;
981 }
982
983 error = misc_register(&monitor_device);
984 if (error) {
985 log_print("misc_register failed for monitor device");
986 misc_deregister(&ctl_device);
987 }
988 out:
989 return error;
990 }
991
992 void dlm_user_exit(void)
993 {
994 misc_deregister(&ctl_device);
995 misc_deregister(&monitor_device);
996 }
997
A cbs scheduler for rt-kernel