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Fix and clean top .gitignore
[linux-2.6.git] / fs / dlm / user.c
blobebbcf38fd33b098143d04e0b575b7028905fd45e
1 /*
2 * Copyright (C) 2006-2007 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
30 #ifdef CONFIG_COMPAT
31
32 struct dlm_lock_params32 {
33 __u8 mode;
34 __u8 namelen;
35 __u16 unused;
36 __u32 flags;
37 __u32 lkid;
38 __u32 parent;
39 __u64 xid;
40 __u64 timeout;
41 __u32 castparam;
42 __u32 castaddr;
43 __u32 bastparam;
44 __u32 bastaddr;
45 __u32 lksb;
46 char lvb[DLM_USER_LVB_LEN];
47 char name[0];
48 };
49
50 struct dlm_write_request32 {
51 __u32 version[3];
52 __u8 cmd;
53 __u8 is64bit;
54 __u8 unused[2];
55
56 union {
57 struct dlm_lock_params32 lock;
58 struct dlm_lspace_params lspace;
59 struct dlm_purge_params purge;
60 } i;
61 };
62
63 struct dlm_lksb32 {
64 __u32 sb_status;
65 __u32 sb_lkid;
66 __u8 sb_flags;
67 __u32 sb_lvbptr;
68 };
69
70 struct dlm_lock_result32 {
71 __u32 version[3];
72 __u32 length;
73 __u32 user_astaddr;
74 __u32 user_astparam;
75 __u32 user_lksb;
76 struct dlm_lksb32 lksb;
77 __u8 bast_mode;
78 __u8 unused[3];
79 /* Offsets may be zero if no data is present */
80 __u32 lvb_offset;
81 };
82
83 static void compat_input(struct dlm_write_request *kb,
84 struct dlm_write_request32 *kb32,
85 size_t count)
86 {
87 kb->version[0] = kb32->version[0];
88 kb->version[1] = kb32->version[1];
89 kb->version[2] = kb32->version[2];
90
91 kb->cmd = kb32->cmd;
92 kb->is64bit = kb32->is64bit;
93 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
94 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
95 kb->i.lspace.flags = kb32->i.lspace.flags;
96 kb->i.lspace.minor = kb32->i.lspace.minor;
97 memcpy(kb->i.lspace.name, kb32->i.lspace.name, count -
98 offsetof(struct dlm_write_request32, i.lspace.name));
99 } else if (kb->cmd == DLM_USER_PURGE) {
100 kb->i.purge.nodeid = kb32->i.purge.nodeid;
101 kb->i.purge.pid = kb32->i.purge.pid;
102 } else {
103 kb->i.lock.mode = kb32->i.lock.mode;
104 kb->i.lock.namelen = kb32->i.lock.namelen;
105 kb->i.lock.flags = kb32->i.lock.flags;
106 kb->i.lock.lkid = kb32->i.lock.lkid;
107 kb->i.lock.parent = kb32->i.lock.parent;
108 kb->i.lock.xid = kb32->i.lock.xid;
109 kb->i.lock.timeout = kb32->i.lock.timeout;
110 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
111 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
112 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
113 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
114 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
115 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
116 memcpy(kb->i.lock.name, kb32->i.lock.name, count -
117 offsetof(struct dlm_write_request32, i.lock.name));
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)
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
210 if (!ast_type) {
211 kref_get(&lkb->lkb_ref);
212 list_add_tail(&lkb->lkb_astqueue, &proc->asts);
213 wake_up_interruptible(&proc->wait);
214 }
215 if (type == AST_COMP && (ast_type & AST_COMP))
216 log_debug(ls, "ast overlap %x status %x %x",
217 lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags);
218
219 eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type);
220 if (eol) {
221 lkb->lkb_ast_type &= ~AST_BAST;
222 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
223 }
224
225 /* We want to copy the lvb to userspace when the completion
226 ast is read if the status is 0, the lock has an lvb and
227 lvb_ops says we should. We could probably have set_lvb_lock()
228 set update_user_lvb instead and not need old_mode */
229
230 if ((lkb->lkb_ast_type & AST_COMP) &&
231 (lkb->lkb_lksb->sb_status == 0) &&
232 lkb->lkb_lksb->sb_lvbptr &&
233 dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1])
234 ua->update_user_lvb = 1;
235 else
236 ua->update_user_lvb = 0;
237
238 spin_unlock(&proc->asts_spin);
239
240 if (eol) {
241 spin_lock(&proc->locks_spin);
242 if (!list_empty(&lkb->lkb_ownqueue)) {
243 list_del_init(&lkb->lkb_ownqueue);
244 dlm_put_lkb(lkb);
245 }
246 spin_unlock(&proc->locks_spin);
247 }
248 out:
249 mutex_unlock(&ls->ls_clear_proc_locks);
250 }
251
252 static int device_user_lock(struct dlm_user_proc *proc,
253 struct dlm_lock_params *params)
254 {
255 struct dlm_ls *ls;
256 struct dlm_user_args *ua;
257 int error = -ENOMEM;
258
259 ls = dlm_find_lockspace_local(proc->lockspace);
260 if (!ls)
261 return -ENOENT;
262
263 if (!params->castaddr || !params->lksb) {
264 error = -EINVAL;
265 goto out;
266 }
267
268 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
269 if (!ua)
270 goto out;
271 ua->proc = proc;
272 ua->user_lksb = params->lksb;
273 ua->castparam = params->castparam;
274 ua->castaddr = params->castaddr;
275 ua->bastparam = params->bastparam;
276 ua->bastaddr = params->bastaddr;
277 ua->xid = params->xid;
278
279 if (params->flags & DLM_LKF_CONVERT)
280 error = dlm_user_convert(ls, ua,
281 params->mode, params->flags,
282 params->lkid, params->lvb,
283 (unsigned long) params->timeout);
284 else {
285 error = dlm_user_request(ls, ua,
286 params->mode, params->flags,
287 params->name, params->namelen,
288 (unsigned long) params->timeout);
289 if (!error)
290 error = ua->lksb.sb_lkid;
291 }
292 out:
293 dlm_put_lockspace(ls);
294 return error;
295 }
296
297 static int device_user_unlock(struct dlm_user_proc *proc,
298 struct dlm_lock_params *params)
299 {
300 struct dlm_ls *ls;
301 struct dlm_user_args *ua;
302 int error = -ENOMEM;
303
304 ls = dlm_find_lockspace_local(proc->lockspace);
305 if (!ls)
306 return -ENOENT;
307
308 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
309 if (!ua)
310 goto out;
311 ua->proc = proc;
312 ua->user_lksb = params->lksb;
313 ua->castparam = params->castparam;
314 ua->castaddr = params->castaddr;
315
316 if (params->flags & DLM_LKF_CANCEL)
317 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
318 else
319 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
320 params->lvb);
321 out:
322 dlm_put_lockspace(ls);
323 return error;
324 }
325
326 static int device_user_deadlock(struct dlm_user_proc *proc,
327 struct dlm_lock_params *params)
328 {
329 struct dlm_ls *ls;
330 int error;
331
332 ls = dlm_find_lockspace_local(proc->lockspace);
333 if (!ls)
334 return -ENOENT;
335
336 error = dlm_user_deadlock(ls, params->flags, params->lkid);
337
338 dlm_put_lockspace(ls);
339 return error;
340 }
341
342 static int create_misc_device(struct dlm_ls *ls, char *name)
343 {
344 int error, len;
345
346 error = -ENOMEM;
347 len = strlen(name) + strlen(name_prefix) + 2;
348 ls->ls_device.name = kzalloc(len, GFP_KERNEL);
349 if (!ls->ls_device.name)
350 goto fail;
351
352 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
353 name);
354 ls->ls_device.fops = &device_fops;
355 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
356
357 error = misc_register(&ls->ls_device);
358 if (error) {
359 kfree(ls->ls_device.name);
360 }
361 fail:
362 return error;
363 }
364
365 static int device_user_purge(struct dlm_user_proc *proc,
366 struct dlm_purge_params *params)
367 {
368 struct dlm_ls *ls;
369 int error;
370
371 ls = dlm_find_lockspace_local(proc->lockspace);
372 if (!ls)
373 return -ENOENT;
374
375 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
376
377 dlm_put_lockspace(ls);
378 return error;
379 }
380
381 static int device_create_lockspace(struct dlm_lspace_params *params)
382 {
383 dlm_lockspace_t *lockspace;
384 struct dlm_ls *ls;
385 int error;
386
387 if (!capable(CAP_SYS_ADMIN))
388 return -EPERM;
389
390 error = dlm_new_lockspace(params->name, strlen(params->name),
391 &lockspace, params->flags, DLM_USER_LVB_LEN);
392 if (error)
393 return error;
394
395 ls = dlm_find_lockspace_local(lockspace);
396 if (!ls)
397 return -ENOENT;
398
399 error = create_misc_device(ls, params->name);
400 dlm_put_lockspace(ls);
401
402 if (error)
403 dlm_release_lockspace(lockspace, 0);
404 else
405 error = ls->ls_device.minor;
406
407 return error;
408 }
409
410 static int device_remove_lockspace(struct dlm_lspace_params *params)
411 {
412 dlm_lockspace_t *lockspace;
413 struct dlm_ls *ls;
414 int error, force = 0;
415
416 if (!capable(CAP_SYS_ADMIN))
417 return -EPERM;
418
419 ls = dlm_find_lockspace_device(params->minor);
420 if (!ls)
421 return -ENOENT;
422
423 /* Deregister the misc device first, so we don't have
424 * a device that's not attached to a lockspace. If
425 * dlm_release_lockspace fails then we can recreate it
426 */
427 error = misc_deregister(&ls->ls_device);
428 if (error) {
429 dlm_put_lockspace(ls);
430 goto out;
431 }
432 kfree(ls->ls_device.name);
433
434 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
435 force = 2;
436
437 lockspace = ls->ls_local_handle;
438
439 /* dlm_release_lockspace waits for references to go to zero,
440 so all processes will need to close their device for the ls
441 before the release will procede */
442
443 dlm_put_lockspace(ls);
444 error = dlm_release_lockspace(lockspace, force);
445 if (error)
446 create_misc_device(ls, ls->ls_name);
447 out:
448 return error;
449 }
450
451 /* Check the user's version matches ours */
452 static int check_version(struct dlm_write_request *req)
453 {
454 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
455 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
456 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
457
458 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
459 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
460 current->comm,
461 task_pid_nr(current),
462 req->version[0],
463 req->version[1],
464 req->version[2],
465 DLM_DEVICE_VERSION_MAJOR,
466 DLM_DEVICE_VERSION_MINOR,
467 DLM_DEVICE_VERSION_PATCH);
468 return -EINVAL;
469 }
470 return 0;
471 }
472
473 /*
474 * device_write
475 *
476 * device_user_lock
477 * dlm_user_request -> request_lock
478 * dlm_user_convert -> convert_lock
479 *
480 * device_user_unlock
481 * dlm_user_unlock -> unlock_lock
482 * dlm_user_cancel -> cancel_lock
483 *
484 * device_create_lockspace
485 * dlm_new_lockspace
486 *
487 * device_remove_lockspace
488 * dlm_release_lockspace
489 */
490
491 /* a write to a lockspace device is a lock or unlock request, a write
492 to the control device is to create/remove a lockspace */
493
494 static ssize_t device_write(struct file *file, const char __user *buf,
495 size_t count, loff_t *ppos)
496 {
497 struct dlm_user_proc *proc = file->private_data;
498 struct dlm_write_request *kbuf;
499 sigset_t tmpsig, allsigs;
500 int error;
501
502 #ifdef CONFIG_COMPAT
503 if (count < sizeof(struct dlm_write_request32))
504 #else
505 if (count < sizeof(struct dlm_write_request))
506 #endif
507 return -EINVAL;
508
509 kbuf = kzalloc(count + 1, GFP_KERNEL);
510 if (!kbuf)
511 return -ENOMEM;
512
513 if (copy_from_user(kbuf, buf, count)) {
514 error = -EFAULT;
515 goto out_free;
516 }
517
518 if (check_version(kbuf)) {
519 error = -EBADE;
520 goto out_free;
521 }
522
523 #ifdef CONFIG_COMPAT
524 if (!kbuf->is64bit) {
525 struct dlm_write_request32 *k32buf;
526 k32buf = (struct dlm_write_request32 *)kbuf;
527 kbuf = kmalloc(count + 1 + (sizeof(struct dlm_write_request) -
528 sizeof(struct dlm_write_request32)), GFP_KERNEL);
529 if (!kbuf)
530 return -ENOMEM;
531
532 if (proc)
533 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
534 compat_input(kbuf, k32buf, count + 1);
535 kfree(k32buf);
536 }
537 #endif
538
539 /* do we really need this? can a write happen after a close? */
540 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
541 test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
542 return -EINVAL;
543
544 sigfillset(&allsigs);
545 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
546
547 error = -EINVAL;
548
549 switch (kbuf->cmd)
550 {
551 case DLM_USER_LOCK:
552 if (!proc) {
553 log_print("no locking on control device");
554 goto out_sig;
555 }
556 error = device_user_lock(proc, &kbuf->i.lock);
557 break;
558
559 case DLM_USER_UNLOCK:
560 if (!proc) {
561 log_print("no locking on control device");
562 goto out_sig;
563 }
564 error = device_user_unlock(proc, &kbuf->i.lock);
565 break;
566
567 case DLM_USER_DEADLOCK:
568 if (!proc) {
569 log_print("no locking on control device");
570 goto out_sig;
571 }
572 error = device_user_deadlock(proc, &kbuf->i.lock);
573 break;
574
575 case DLM_USER_CREATE_LOCKSPACE:
576 if (proc) {
577 log_print("create/remove only on control device");
578 goto out_sig;
579 }
580 error = device_create_lockspace(&kbuf->i.lspace);
581 break;
582
583 case DLM_USER_REMOVE_LOCKSPACE:
584 if (proc) {
585 log_print("create/remove only on control device");
586 goto out_sig;
587 }
588 error = device_remove_lockspace(&kbuf->i.lspace);
589 break;
590
591 case DLM_USER_PURGE:
592 if (!proc) {
593 log_print("no locking on control device");
594 goto out_sig;
595 }
596 error = device_user_purge(proc, &kbuf->i.purge);
597 break;
598
599 default:
600 log_print("Unknown command passed to DLM device : %d\n",
601 kbuf->cmd);
602 }
603
604 out_sig:
605 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
606 recalc_sigpending();
607 out_free:
608 kfree(kbuf);
609 return error;
610 }
611
612 /* Every process that opens the lockspace device has its own "proc" structure
613 hanging off the open file that's used to keep track of locks owned by the
614 process and asts that need to be delivered to the process. */
615
616 static int device_open(struct inode *inode, struct file *file)
617 {
618 struct dlm_user_proc *proc;
619 struct dlm_ls *ls;
620
621 ls = dlm_find_lockspace_device(iminor(inode));
622 if (!ls)
623 return -ENOENT;
624
625 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
626 if (!proc) {
627 dlm_put_lockspace(ls);
628 return -ENOMEM;
629 }
630
631 proc->lockspace = ls->ls_local_handle;
632 INIT_LIST_HEAD(&proc->asts);
633 INIT_LIST_HEAD(&proc->locks);
634 INIT_LIST_HEAD(&proc->unlocking);
635 spin_lock_init(&proc->asts_spin);
636 spin_lock_init(&proc->locks_spin);
637 init_waitqueue_head(&proc->wait);
638 file->private_data = proc;
639
640 return 0;
641 }
642
643 static int device_close(struct inode *inode, struct file *file)
644 {
645 struct dlm_user_proc *proc = file->private_data;
646 struct dlm_ls *ls;
647 sigset_t tmpsig, allsigs;
648
649 ls = dlm_find_lockspace_local(proc->lockspace);
650 if (!ls)
651 return -ENOENT;
652
653 sigfillset(&allsigs);
654 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
655
656 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
657
658 dlm_clear_proc_locks(ls, proc);
659
660 /* at this point no more lkb's should exist for this lockspace,
661 so there's no chance of dlm_user_add_ast() being called and
662 looking for lkb->ua->proc */
663
664 kfree(proc);
665 file->private_data = NULL;
666
667 dlm_put_lockspace(ls);
668 dlm_put_lockspace(ls); /* for the find in device_open() */
669
670 /* FIXME: AUTOFREE: if this ls is no longer used do
671 device_remove_lockspace() */
672
673 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
674 recalc_sigpending();
675
676 return 0;
677 }
678
679 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type,
680 int bmode, char __user *buf, size_t count)
681 {
682 #ifdef CONFIG_COMPAT
683 struct dlm_lock_result32 result32;
684 #endif
685 struct dlm_lock_result result;
686 void *resultptr;
687 int error=0;
688 int len;
689 int struct_len;
690
691 memset(&result, 0, sizeof(struct dlm_lock_result));
692 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
693 result.version[1] = DLM_DEVICE_VERSION_MINOR;
694 result.version[2] = DLM_DEVICE_VERSION_PATCH;
695 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
696 result.user_lksb = ua->user_lksb;
697
698 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
699 in a conversion unless the conversion is successful. See code
700 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
701 notes that a new blocking AST address and parameter are set even if
702 the conversion fails, so maybe we should just do that. */
703
704 if (type == AST_BAST) {
705 result.user_astaddr = ua->bastaddr;
706 result.user_astparam = ua->bastparam;
707 result.bast_mode = bmode;
708 } else {
709 result.user_astaddr = ua->castaddr;
710 result.user_astparam = ua->castparam;
711 }
712
713 #ifdef CONFIG_COMPAT
714 if (compat)
715 len = sizeof(struct dlm_lock_result32);
716 else
717 #endif
718 len = sizeof(struct dlm_lock_result);
719 struct_len = len;
720
721 /* copy lvb to userspace if there is one, it's been updated, and
722 the user buffer has space for it */
723
724 if (ua->update_user_lvb && ua->lksb.sb_lvbptr &&
725 count >= len + DLM_USER_LVB_LEN) {
726 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
727 DLM_USER_LVB_LEN)) {
728 error = -EFAULT;
729 goto out;
730 }
731
732 result.lvb_offset = len;
733 len += DLM_USER_LVB_LEN;
734 }
735
736 result.length = len;
737 resultptr = &result;
738 #ifdef CONFIG_COMPAT
739 if (compat) {
740 compat_output(&result, &result32);
741 resultptr = &result32;
742 }
743 #endif
744
745 if (copy_to_user(buf, resultptr, struct_len))
746 error = -EFAULT;
747 else
748 error = len;
749 out:
750 return error;
751 }
752
753 static int copy_version_to_user(char __user *buf, size_t count)
754 {
755 struct dlm_device_version ver;
756
757 memset(&ver, 0, sizeof(struct dlm_device_version));
758 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
759 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
760 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
761
762 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
763 return -EFAULT;
764 return sizeof(struct dlm_device_version);
765 }
766
767 /* a read returns a single ast described in a struct dlm_lock_result */
768
769 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
770 loff_t *ppos)
771 {
772 struct dlm_user_proc *proc = file->private_data;
773 struct dlm_lkb *lkb;
774 DECLARE_WAITQUEUE(wait, current);
775 int error, type=0, bmode=0, removed = 0;
776
777 if (count == sizeof(struct dlm_device_version)) {
778 error = copy_version_to_user(buf, count);
779 return error;
780 }
781
782 if (!proc) {
783 log_print("non-version read from control device %zu", count);
784 return -EINVAL;
785 }
786
787 #ifdef CONFIG_COMPAT
788 if (count < sizeof(struct dlm_lock_result32))
789 #else
790 if (count < sizeof(struct dlm_lock_result))
791 #endif
792 return -EINVAL;
793
794 /* do we really need this? can a read happen after a close? */
795 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
796 return -EINVAL;
797
798 spin_lock(&proc->asts_spin);
799 if (list_empty(&proc->asts)) {
800 if (file->f_flags & O_NONBLOCK) {
801 spin_unlock(&proc->asts_spin);
802 return -EAGAIN;
803 }
804
805 add_wait_queue(&proc->wait, &wait);
806
807 repeat:
808 set_current_state(TASK_INTERRUPTIBLE);
809 if (list_empty(&proc->asts) && !signal_pending(current)) {
810 spin_unlock(&proc->asts_spin);
811 schedule();
812 spin_lock(&proc->asts_spin);
813 goto repeat;
814 }
815 set_current_state(TASK_RUNNING);
816 remove_wait_queue(&proc->wait, &wait);
817
818 if (signal_pending(current)) {
819 spin_unlock(&proc->asts_spin);
820 return -ERESTARTSYS;
821 }
822 }
823
824 /* there may be both completion and blocking asts to return for
825 the lkb, don't remove lkb from asts list unless no asts remain */
826
827 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue);
828
829 if (lkb->lkb_ast_type & AST_COMP) {
830 lkb->lkb_ast_type &= ~AST_COMP;
831 type = AST_COMP;
832 } else if (lkb->lkb_ast_type & AST_BAST) {
833 lkb->lkb_ast_type &= ~AST_BAST;
834 type = AST_BAST;
835 bmode = lkb->lkb_bastmode;
836 }
837
838 if (!lkb->lkb_ast_type) {
839 list_del(&lkb->lkb_astqueue);
840 removed = 1;
841 }
842 spin_unlock(&proc->asts_spin);
843
844 error = copy_result_to_user(lkb->lkb_ua,
845 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
846 type, bmode, buf, count);
847
848 /* removes reference for the proc->asts lists added by
849 dlm_user_add_ast() and may result in the lkb being freed */
850 if (removed)
851 dlm_put_lkb(lkb);
852
853 return error;
854 }
855
856 static unsigned int device_poll(struct file *file, poll_table *wait)
857 {
858 struct dlm_user_proc *proc = file->private_data;
859
860 poll_wait(file, &proc->wait, wait);
861
862 spin_lock(&proc->asts_spin);
863 if (!list_empty(&proc->asts)) {
864 spin_unlock(&proc->asts_spin);
865 return POLLIN | POLLRDNORM;
866 }
867 spin_unlock(&proc->asts_spin);
868 return 0;
869 }
870
871 static int ctl_device_open(struct inode *inode, struct file *file)
872 {
873 file->private_data = NULL;
874 return 0;
875 }
876
877 static int ctl_device_close(struct inode *inode, struct file *file)
878 {
879 return 0;
880 }
881
882 static const struct file_operations device_fops = {
883 .open = device_open,
884 .release = device_close,
885 .read = device_read,
886 .write = device_write,
887 .poll = device_poll,
888 .owner = THIS_MODULE,
889 };
890
891 static const struct file_operations ctl_device_fops = {
892 .open = ctl_device_open,
893 .release = ctl_device_close,
894 .read = device_read,
895 .write = device_write,
896 .owner = THIS_MODULE,
897 };
898
899 static struct miscdevice ctl_device = {
900 .name = "dlm-control",
901 .fops = &ctl_device_fops,
902 .minor = MISC_DYNAMIC_MINOR,
903 };
904
905 int __init dlm_user_init(void)
906 {
907 int error;
908
909 error = misc_register(&ctl_device);
910 if (error)
911 log_print("misc_register failed for control device");
912
913 return error;
914 }
915
916 void dlm_user_exit(void)
917 {
918 misc_deregister(&ctl_device);
919 }
920
Linus' kernel tree