?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Revert "ahci: added support for Freescale AHCI sata"
[linux-2.6/btrfs-unstable.git] / fs / dlm / user.c
blob173b3873a4f4ee94a42c9ffa821e6d64ce902d07
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 uint32_t lkid;
242 int error = -ENOMEM;
243
244 ls = dlm_find_lockspace_local(proc->lockspace);
245 if (!ls)
246 return -ENOENT;
247
248 if (!params->castaddr || !params->lksb) {
249 error = -EINVAL;
250 goto out;
251 }
252
253 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
254 if (!ua)
255 goto out;
256 ua->proc = proc;
257 ua->user_lksb = params->lksb;
258 ua->castparam = params->castparam;
259 ua->castaddr = params->castaddr;
260 ua->bastparam = params->bastparam;
261 ua->bastaddr = params->bastaddr;
262 ua->xid = params->xid;
263
264 if (params->flags & DLM_LKF_CONVERT) {
265 error = dlm_user_convert(ls, ua,
266 params->mode, params->flags,
267 params->lkid, params->lvb,
268 (unsigned long) params->timeout);
269 } else if (params->flags & DLM_LKF_ORPHAN) {
270 error = dlm_user_adopt_orphan(ls, ua,
271 params->mode, params->flags,
272 params->name, params->namelen,
273 (unsigned long) params->timeout,
274 &lkid);
275 if (!error)
276 error = lkid;
277 } else {
278 error = dlm_user_request(ls, ua,
279 params->mode, params->flags,
280 params->name, params->namelen,
281 (unsigned long) params->timeout);
282 if (!error)
283 error = ua->lksb.sb_lkid;
284 }
285 out:
286 dlm_put_lockspace(ls);
287 return error;
288 }
289
290 static int device_user_unlock(struct dlm_user_proc *proc,
291 struct dlm_lock_params *params)
292 {
293 struct dlm_ls *ls;
294 struct dlm_user_args *ua;
295 int error = -ENOMEM;
296
297 ls = dlm_find_lockspace_local(proc->lockspace);
298 if (!ls)
299 return -ENOENT;
300
301 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
302 if (!ua)
303 goto out;
304 ua->proc = proc;
305 ua->user_lksb = params->lksb;
306 ua->castparam = params->castparam;
307 ua->castaddr = params->castaddr;
308
309 if (params->flags & DLM_LKF_CANCEL)
310 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
311 else
312 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
313 params->lvb);
314 out:
315 dlm_put_lockspace(ls);
316 return error;
317 }
318
319 static int device_user_deadlock(struct dlm_user_proc *proc,
320 struct dlm_lock_params *params)
321 {
322 struct dlm_ls *ls;
323 int error;
324
325 ls = dlm_find_lockspace_local(proc->lockspace);
326 if (!ls)
327 return -ENOENT;
328
329 error = dlm_user_deadlock(ls, params->flags, params->lkid);
330
331 dlm_put_lockspace(ls);
332 return error;
333 }
334
335 static int dlm_device_register(struct dlm_ls *ls, char *name)
336 {
337 int error, len;
338
339 /* The device is already registered. This happens when the
340 lockspace is created multiple times from userspace. */
341 if (ls->ls_device.name)
342 return 0;
343
344 error = -ENOMEM;
345 len = strlen(name) + strlen(name_prefix) + 2;
346 ls->ls_device.name = kzalloc(len, GFP_NOFS);
347 if (!ls->ls_device.name)
348 goto fail;
349
350 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
351 name);
352 ls->ls_device.fops = &device_fops;
353 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
354
355 error = misc_register(&ls->ls_device);
356 if (error) {
357 kfree(ls->ls_device.name);
358 }
359 fail:
360 return error;
361 }
362
363 int dlm_device_deregister(struct dlm_ls *ls)
364 {
365 /* The device is not registered. This happens when the lockspace
366 was never used from userspace, or when device_create_lockspace()
367 calls dlm_release_lockspace() after the register fails. */
368 if (!ls->ls_device.name)
369 return 0;
370
371 misc_deregister(&ls->ls_device);
372 kfree(ls->ls_device.name);
373 return 0;
374 }
375
376 static int device_user_purge(struct dlm_user_proc *proc,
377 struct dlm_purge_params *params)
378 {
379 struct dlm_ls *ls;
380 int error;
381
382 ls = dlm_find_lockspace_local(proc->lockspace);
383 if (!ls)
384 return -ENOENT;
385
386 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
387
388 dlm_put_lockspace(ls);
389 return error;
390 }
391
392 static int device_create_lockspace(struct dlm_lspace_params *params)
393 {
394 dlm_lockspace_t *lockspace;
395 struct dlm_ls *ls;
396 int error;
397
398 if (!capable(CAP_SYS_ADMIN))
399 return -EPERM;
400
401 error = dlm_new_lockspace(params->name, NULL, params->flags,
402 DLM_USER_LVB_LEN, NULL, NULL, NULL,
403 &lockspace);
404 if (error)
405 return error;
406
407 ls = dlm_find_lockspace_local(lockspace);
408 if (!ls)
409 return -ENOENT;
410
411 error = dlm_device_register(ls, params->name);
412 dlm_put_lockspace(ls);
413
414 if (error)
415 dlm_release_lockspace(lockspace, 0);
416 else
417 error = ls->ls_device.minor;
418
419 return error;
420 }
421
422 static int device_remove_lockspace(struct dlm_lspace_params *params)
423 {
424 dlm_lockspace_t *lockspace;
425 struct dlm_ls *ls;
426 int error, force = 0;
427
428 if (!capable(CAP_SYS_ADMIN))
429 return -EPERM;
430
431 ls = dlm_find_lockspace_device(params->minor);
432 if (!ls)
433 return -ENOENT;
434
435 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
436 force = 2;
437
438 lockspace = ls->ls_local_handle;
439 dlm_put_lockspace(ls);
440
441 /* The final dlm_release_lockspace waits for references to go to
442 zero, so all processes will need to close their device for the
443 ls before the release will proceed. release also calls the
444 device_deregister above. Converting a positive return value
445 from release to zero means that userspace won't know when its
446 release was the final one, but it shouldn't need to know. */
447
448 error = dlm_release_lockspace(lockspace, force);
449 if (error > 0)
450 error = 0;
451 return error;
452 }
453
454 /* Check the user's version matches ours */
455 static int check_version(struct dlm_write_request *req)
456 {
457 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
458 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
459 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
460
461 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
462 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
463 current->comm,
464 task_pid_nr(current),
465 req->version[0],
466 req->version[1],
467 req->version[2],
468 DLM_DEVICE_VERSION_MAJOR,
469 DLM_DEVICE_VERSION_MINOR,
470 DLM_DEVICE_VERSION_PATCH);
471 return -EINVAL;
472 }
473 return 0;
474 }
475
476 /*
477 * device_write
478 *
479 * device_user_lock
480 * dlm_user_request -> request_lock
481 * dlm_user_convert -> convert_lock
482 *
483 * device_user_unlock
484 * dlm_user_unlock -> unlock_lock
485 * dlm_user_cancel -> cancel_lock
486 *
487 * device_create_lockspace
488 * dlm_new_lockspace
489 *
490 * device_remove_lockspace
491 * dlm_release_lockspace
492 */
493
494 /* a write to a lockspace device is a lock or unlock request, a write
495 to the control device is to create/remove a lockspace */
496
497 static ssize_t device_write(struct file *file, const char __user *buf,
498 size_t count, loff_t *ppos)
499 {
500 struct dlm_user_proc *proc = file->private_data;
501 struct dlm_write_request *kbuf;
502 int error;
503
504 #ifdef CONFIG_COMPAT
505 if (count < sizeof(struct dlm_write_request32))
506 #else
507 if (count < sizeof(struct dlm_write_request))
508 #endif
509 return -EINVAL;
510
511 /*
512 * can't compare against COMPAT/dlm_write_request32 because
513 * we don't yet know if is64bit is zero
514 */
515 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
516 return -EINVAL;
517
518 kbuf = kzalloc(count + 1, GFP_NOFS);
519 if (!kbuf)
520 return -ENOMEM;
521
522 if (copy_from_user(kbuf, buf, count)) {
523 error = -EFAULT;
524 goto out_free;
525 }
526
527 if (check_version(kbuf)) {
528 error = -EBADE;
529 goto out_free;
530 }
531
532 #ifdef CONFIG_COMPAT
533 if (!kbuf->is64bit) {
534 struct dlm_write_request32 *k32buf;
535 int namelen = 0;
536
537 if (count > sizeof(struct dlm_write_request32))
538 namelen = count - sizeof(struct dlm_write_request32);
539
540 k32buf = (struct dlm_write_request32 *)kbuf;
541
542 /* add 1 after namelen so that the name string is terminated */
543 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
544 GFP_NOFS);
545 if (!kbuf) {
546 kfree(k32buf);
547 return -ENOMEM;
548 }
549
550 if (proc)
551 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
552
553 compat_input(kbuf, k32buf, namelen);
554 kfree(k32buf);
555 }
556 #endif
557
558 /* do we really need this? can a write happen after a close? */
559 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
560 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
561 error = -EINVAL;
562 goto out_free;
563 }
564
565 error = -EINVAL;
566
567 switch (kbuf->cmd)
568 {
569 case DLM_USER_LOCK:
570 if (!proc) {
571 log_print("no locking on control device");
572 goto out_free;
573 }
574 error = device_user_lock(proc, &kbuf->i.lock);
575 break;
576
577 case DLM_USER_UNLOCK:
578 if (!proc) {
579 log_print("no locking on control device");
580 goto out_free;
581 }
582 error = device_user_unlock(proc, &kbuf->i.lock);
583 break;
584
585 case DLM_USER_DEADLOCK:
586 if (!proc) {
587 log_print("no locking on control device");
588 goto out_free;
589 }
590 error = device_user_deadlock(proc, &kbuf->i.lock);
591 break;
592
593 case DLM_USER_CREATE_LOCKSPACE:
594 if (proc) {
595 log_print("create/remove only on control device");
596 goto out_free;
597 }
598 error = device_create_lockspace(&kbuf->i.lspace);
599 break;
600
601 case DLM_USER_REMOVE_LOCKSPACE:
602 if (proc) {
603 log_print("create/remove only on control device");
604 goto out_free;
605 }
606 error = device_remove_lockspace(&kbuf->i.lspace);
607 break;
608
609 case DLM_USER_PURGE:
610 if (!proc) {
611 log_print("no locking on control device");
612 goto out_free;
613 }
614 error = device_user_purge(proc, &kbuf->i.purge);
615 break;
616
617 default:
618 log_print("Unknown command passed to DLM device : %d\n",
619 kbuf->cmd);
620 }
621
622 out_free:
623 kfree(kbuf);
624 return error;
625 }
626
627 /* Every process that opens the lockspace device has its own "proc" structure
628 hanging off the open file that's used to keep track of locks owned by the
629 process and asts that need to be delivered to the process. */
630
631 static int device_open(struct inode *inode, struct file *file)
632 {
633 struct dlm_user_proc *proc;
634 struct dlm_ls *ls;
635
636 ls = dlm_find_lockspace_device(iminor(inode));
637 if (!ls)
638 return -ENOENT;
639
640 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
641 if (!proc) {
642 dlm_put_lockspace(ls);
643 return -ENOMEM;
644 }
645
646 proc->lockspace = ls->ls_local_handle;
647 INIT_LIST_HEAD(&proc->asts);
648 INIT_LIST_HEAD(&proc->locks);
649 INIT_LIST_HEAD(&proc->unlocking);
650 spin_lock_init(&proc->asts_spin);
651 spin_lock_init(&proc->locks_spin);
652 init_waitqueue_head(&proc->wait);
653 file->private_data = proc;
654
655 return 0;
656 }
657
658 static int device_close(struct inode *inode, struct file *file)
659 {
660 struct dlm_user_proc *proc = file->private_data;
661 struct dlm_ls *ls;
662
663 ls = dlm_find_lockspace_local(proc->lockspace);
664 if (!ls)
665 return -ENOENT;
666
667 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
668
669 dlm_clear_proc_locks(ls, proc);
670
671 /* at this point no more lkb's should exist for this lockspace,
672 so there's no chance of dlm_user_add_ast() being called and
673 looking for lkb->ua->proc */
674
675 kfree(proc);
676 file->private_data = NULL;
677
678 dlm_put_lockspace(ls);
679 dlm_put_lockspace(ls); /* for the find in device_open() */
680
681 /* FIXME: AUTOFREE: if this ls is no longer used do
682 device_remove_lockspace() */
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 int old_mode, new_mode;
786
787 if (count == sizeof(struct dlm_device_version)) {
788 rv = copy_version_to_user(buf, count);
789 return rv;
790 }
791
792 if (!proc) {
793 log_print("non-version read from control device %zu", count);
794 return -EINVAL;
795 }
796
797 #ifdef CONFIG_COMPAT
798 if (count < sizeof(struct dlm_lock_result32))
799 #else
800 if (count < sizeof(struct dlm_lock_result))
801 #endif
802 return -EINVAL;
803
804 try_another:
805
806 /* do we really need this? can a read happen after a close? */
807 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
808 return -EINVAL;
809
810 spin_lock(&proc->asts_spin);
811 if (list_empty(&proc->asts)) {
812 if (file->f_flags & O_NONBLOCK) {
813 spin_unlock(&proc->asts_spin);
814 return -EAGAIN;
815 }
816
817 add_wait_queue(&proc->wait, &wait);
818
819 repeat:
820 set_current_state(TASK_INTERRUPTIBLE);
821 if (list_empty(&proc->asts) && !signal_pending(current)) {
822 spin_unlock(&proc->asts_spin);
823 schedule();
824 spin_lock(&proc->asts_spin);
825 goto repeat;
826 }
827 set_current_state(TASK_RUNNING);
828 remove_wait_queue(&proc->wait, &wait);
829
830 if (signal_pending(current)) {
831 spin_unlock(&proc->asts_spin);
832 return -ERESTARTSYS;
833 }
834 }
835
836 /* if we empty lkb_callbacks, we don't want to unlock the spinlock
837 without removing lkb_cb_list; so empty lkb_cb_list is always
838 consistent with empty lkb_callbacks */
839
840 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
841
842 /* rem_lkb_callback sets a new lkb_last_cast */
843 old_mode = lkb->lkb_last_cast.mode;
844
845 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
846 if (rv < 0) {
847 /* this shouldn't happen; lkb should have been removed from
848 list when resid was zero */
849 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
850 list_del_init(&lkb->lkb_cb_list);
851 spin_unlock(&proc->asts_spin);
852 /* removes ref for proc->asts, may cause lkb to be freed */
853 dlm_put_lkb(lkb);
854 goto try_another;
855 }
856 if (!resid)
857 list_del_init(&lkb->lkb_cb_list);
858 spin_unlock(&proc->asts_spin);
859
860 if (cb.flags & DLM_CB_SKIP) {
861 /* removes ref for proc->asts, may cause lkb to be freed */
862 if (!resid)
863 dlm_put_lkb(lkb);
864 goto try_another;
865 }
866
867 if (cb.flags & DLM_CB_CAST) {
868 new_mode = cb.mode;
869
870 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
871 dlm_lvb_operations[old_mode + 1][new_mode + 1])
872 copy_lvb = 1;
873
874 lkb->lkb_lksb->sb_status = cb.sb_status;
875 lkb->lkb_lksb->sb_flags = cb.sb_flags;
876 }
877
878 rv = copy_result_to_user(lkb->lkb_ua,
879 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
880 cb.flags, cb.mode, copy_lvb, buf, count);
881
882 /* removes ref for proc->asts, may cause lkb to be freed */
883 if (!resid)
884 dlm_put_lkb(lkb);
885
886 return rv;
887 }
888
889 static unsigned int device_poll(struct file *file, poll_table *wait)
890 {
891 struct dlm_user_proc *proc = file->private_data;
892
893 poll_wait(file, &proc->wait, wait);
894
895 spin_lock(&proc->asts_spin);
896 if (!list_empty(&proc->asts)) {
897 spin_unlock(&proc->asts_spin);
898 return POLLIN | POLLRDNORM;
899 }
900 spin_unlock(&proc->asts_spin);
901 return 0;
902 }
903
904 int dlm_user_daemon_available(void)
905 {
906 /* dlm_controld hasn't started (or, has started, but not
907 properly populated configfs) */
908
909 if (!dlm_our_nodeid())
910 return 0;
911
912 /* This is to deal with versions of dlm_controld that don't
913 know about the monitor device. We assume that if the
914 dlm_controld was started (above), but the monitor device
915 was never opened, that it's an old version. dlm_controld
916 should open the monitor device before populating configfs. */
917
918 if (dlm_monitor_unused)
919 return 1;
920
921 return atomic_read(&dlm_monitor_opened) ? 1 : 0;
922 }
923
924 static int ctl_device_open(struct inode *inode, struct file *file)
925 {
926 file->private_data = NULL;
927 return 0;
928 }
929
930 static int ctl_device_close(struct inode *inode, struct file *file)
931 {
932 return 0;
933 }
934
935 static int monitor_device_open(struct inode *inode, struct file *file)
936 {
937 atomic_inc(&dlm_monitor_opened);
938 dlm_monitor_unused = 0;
939 return 0;
940 }
941
942 static int monitor_device_close(struct inode *inode, struct file *file)
943 {
944 if (atomic_dec_and_test(&dlm_monitor_opened))
945 dlm_stop_lockspaces();
946 return 0;
947 }
948
949 static const struct file_operations device_fops = {
950 .open = device_open,
951 .release = device_close,
952 .read = device_read,
953 .write = device_write,
954 .poll = device_poll,
955 .owner = THIS_MODULE,
956 .llseek = noop_llseek,
957 };
958
959 static const struct file_operations ctl_device_fops = {
960 .open = ctl_device_open,
961 .release = ctl_device_close,
962 .read = device_read,
963 .write = device_write,
964 .owner = THIS_MODULE,
965 .llseek = noop_llseek,
966 };
967
968 static struct miscdevice ctl_device = {
969 .name = "dlm-control",
970 .fops = &ctl_device_fops,
971 .minor = MISC_DYNAMIC_MINOR,
972 };
973
974 static const struct file_operations monitor_device_fops = {
975 .open = monitor_device_open,
976 .release = monitor_device_close,
977 .owner = THIS_MODULE,
978 .llseek = noop_llseek,
979 };
980
981 static struct miscdevice monitor_device = {
982 .name = "dlm-monitor",
983 .fops = &monitor_device_fops,
984 .minor = MISC_DYNAMIC_MINOR,
985 };
986
987 int __init dlm_user_init(void)
988 {
989 int error;
990
991 atomic_set(&dlm_monitor_opened, 0);
992
993 error = misc_register(&ctl_device);
994 if (error) {
995 log_print("misc_register failed for control device");
996 goto out;
997 }
998
999 error = misc_register(&monitor_device);
1000 if (error) {
1001 log_print("misc_register failed for monitor device");
1002 misc_deregister(&ctl_device);
1003 }
1004 out:
1005 return error;
1006 }
1007
1008 void dlm_user_exit(void)
1009 {
1010 misc_deregister(&ctl_device);
1011 misc_deregister(&monitor_device);
1012 }
1013
(deprecated) Btrfs devel tree