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IRQ: check for PERCPU flag only when adding first irqaction
[linux-2.6/openmoko-kernel.git] / fs / dlm / user.c
blobb0201ec325a79578761a686c85ab376944ec2abe
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 struct miscdevice ctl_device;
29 static const struct file_operations device_fops;
30
31 #ifdef CONFIG_COMPAT
32
33 struct dlm_lock_params32 {
34 __u8 mode;
35 __u8 namelen;
36 __u16 flags;
37 __u32 lkid;
38 __u32 parent;
39
40 __u32 castparam;
41 __u32 castaddr;
42 __u32 bastparam;
43 __u32 bastaddr;
44 __u32 lksb;
45
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 length;
72 __u32 user_astaddr;
73 __u32 user_astparam;
74 __u32 user_lksb;
75 struct dlm_lksb32 lksb;
76 __u8 bast_mode;
77 __u8 unused[3];
78 /* Offsets may be zero if no data is present */
79 __u32 lvb_offset;
80 };
81
82 static void compat_input(struct dlm_write_request *kb,
83 struct dlm_write_request32 *kb32)
84 {
85 kb->version[0] = kb32->version[0];
86 kb->version[1] = kb32->version[1];
87 kb->version[2] = kb32->version[2];
88
89 kb->cmd = kb32->cmd;
90 kb->is64bit = kb32->is64bit;
91 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
92 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
93 kb->i.lspace.flags = kb32->i.lspace.flags;
94 kb->i.lspace.minor = kb32->i.lspace.minor;
95 strcpy(kb->i.lspace.name, kb32->i.lspace.name);
96 } else if (kb->cmd == DLM_USER_PURGE) {
97 kb->i.purge.nodeid = kb32->i.purge.nodeid;
98 kb->i.purge.pid = kb32->i.purge.pid;
99 } else {
100 kb->i.lock.mode = kb32->i.lock.mode;
101 kb->i.lock.namelen = kb32->i.lock.namelen;
102 kb->i.lock.flags = kb32->i.lock.flags;
103 kb->i.lock.lkid = kb32->i.lock.lkid;
104 kb->i.lock.parent = kb32->i.lock.parent;
105 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
106 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
107 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
108 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
109 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
110 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
111 memcpy(kb->i.lock.name, kb32->i.lock.name, kb->i.lock.namelen);
112 }
113 }
114
115 static void compat_output(struct dlm_lock_result *res,
116 struct dlm_lock_result32 *res32)
117 {
118 res32->user_astaddr = (__u32)(long)res->user_astaddr;
119 res32->user_astparam = (__u32)(long)res->user_astparam;
120 res32->user_lksb = (__u32)(long)res->user_lksb;
121 res32->bast_mode = res->bast_mode;
122
123 res32->lvb_offset = res->lvb_offset;
124 res32->length = res->length;
125
126 res32->lksb.sb_status = res->lksb.sb_status;
127 res32->lksb.sb_flags = res->lksb.sb_flags;
128 res32->lksb.sb_lkid = res->lksb.sb_lkid;
129 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
130 }
131 #endif
132
133 /* we could possibly check if the cancel of an orphan has resulted in the lkb
134 being removed and then remove that lkb from the orphans list and free it */
135
136 void dlm_user_add_ast(struct dlm_lkb *lkb, int type)
137 {
138 struct dlm_ls *ls;
139 struct dlm_user_args *ua;
140 struct dlm_user_proc *proc;
141 int eol = 0, ast_type;
142
143 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
144 return;
145
146 ls = lkb->lkb_resource->res_ls;
147 mutex_lock(&ls->ls_clear_proc_locks);
148
149 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
150 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed
151 lkb->ua so we can't try to use it. This second check is necessary
152 for cases where a completion ast is received for an operation that
153 began before clear_proc_locks did its cancel/unlock. */
154
155 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
156 goto out;
157
158 DLM_ASSERT(lkb->lkb_astparam, dlm_print_lkb(lkb););
159 ua = (struct dlm_user_args *)lkb->lkb_astparam;
160 proc = ua->proc;
161
162 if (type == AST_BAST && ua->bastaddr == NULL)
163 goto out;
164
165 spin_lock(&proc->asts_spin);
166
167 ast_type = lkb->lkb_ast_type;
168 lkb->lkb_ast_type |= type;
169
170 if (!ast_type) {
171 kref_get(&lkb->lkb_ref);
172 list_add_tail(&lkb->lkb_astqueue, &proc->asts);
173 wake_up_interruptible(&proc->wait);
174 }
175 if (type == AST_COMP && (ast_type & AST_COMP))
176 log_debug(ls, "ast overlap %x status %x %x",
177 lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags);
178
179 /* Figure out if this lock is at the end of its life and no longer
180 available for the application to use. The lkb still exists until
181 the final ast is read. A lock becomes EOL in three situations:
182 1. a noqueue request fails with EAGAIN
183 2. an unlock completes with EUNLOCK
184 3. a cancel of a waiting request completes with ECANCEL
185 An EOL lock needs to be removed from the process's list of locks.
186 And we can't allow any new operation on an EOL lock. This is
187 not related to the lifetime of the lkb struct which is managed
188 entirely by refcount. */
189
190 if (type == AST_COMP &&
191 lkb->lkb_grmode == DLM_LOCK_IV &&
192 ua->lksb.sb_status == -EAGAIN)
193 eol = 1;
194 else if (ua->lksb.sb_status == -DLM_EUNLOCK ||
195 (ua->lksb.sb_status == -DLM_ECANCEL &&
196 lkb->lkb_grmode == DLM_LOCK_IV))
197 eol = 1;
198 if (eol) {
199 lkb->lkb_ast_type &= ~AST_BAST;
200 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
201 }
202
203 /* We want to copy the lvb to userspace when the completion
204 ast is read if the status is 0, the lock has an lvb and
205 lvb_ops says we should. We could probably have set_lvb_lock()
206 set update_user_lvb instead and not need old_mode */
207
208 if ((lkb->lkb_ast_type & AST_COMP) &&
209 (lkb->lkb_lksb->sb_status == 0) &&
210 lkb->lkb_lksb->sb_lvbptr &&
211 dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1])
212 ua->update_user_lvb = 1;
213 else
214 ua->update_user_lvb = 0;
215
216 spin_unlock(&proc->asts_spin);
217
218 if (eol) {
219 spin_lock(&ua->proc->locks_spin);
220 if (!list_empty(&lkb->lkb_ownqueue)) {
221 list_del_init(&lkb->lkb_ownqueue);
222 dlm_put_lkb(lkb);
223 }
224 spin_unlock(&ua->proc->locks_spin);
225 }
226 out:
227 mutex_unlock(&ls->ls_clear_proc_locks);
228 }
229
230 static int device_user_lock(struct dlm_user_proc *proc,
231 struct dlm_lock_params *params)
232 {
233 struct dlm_ls *ls;
234 struct dlm_user_args *ua;
235 int error = -ENOMEM;
236
237 ls = dlm_find_lockspace_local(proc->lockspace);
238 if (!ls)
239 return -ENOENT;
240
241 if (!params->castaddr || !params->lksb) {
242 error = -EINVAL;
243 goto out;
244 }
245
246 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
247 if (!ua)
248 goto out;
249 ua->proc = proc;
250 ua->user_lksb = params->lksb;
251 ua->castparam = params->castparam;
252 ua->castaddr = params->castaddr;
253 ua->bastparam = params->bastparam;
254 ua->bastaddr = params->bastaddr;
255
256 if (params->flags & DLM_LKF_CONVERT)
257 error = dlm_user_convert(ls, ua,
258 params->mode, params->flags,
259 params->lkid, params->lvb);
260 else {
261 error = dlm_user_request(ls, ua,
262 params->mode, params->flags,
263 params->name, params->namelen,
264 params->parent);
265 if (!error)
266 error = ua->lksb.sb_lkid;
267 }
268 out:
269 dlm_put_lockspace(ls);
270 return error;
271 }
272
273 static int device_user_unlock(struct dlm_user_proc *proc,
274 struct dlm_lock_params *params)
275 {
276 struct dlm_ls *ls;
277 struct dlm_user_args *ua;
278 int error = -ENOMEM;
279
280 ls = dlm_find_lockspace_local(proc->lockspace);
281 if (!ls)
282 return -ENOENT;
283
284 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
285 if (!ua)
286 goto out;
287 ua->proc = proc;
288 ua->user_lksb = params->lksb;
289 ua->castparam = params->castparam;
290 ua->castaddr = params->castaddr;
291
292 if (params->flags & DLM_LKF_CANCEL)
293 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
294 else
295 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
296 params->lvb);
297 out:
298 dlm_put_lockspace(ls);
299 return error;
300 }
301
302 static int create_misc_device(struct dlm_ls *ls, char *name)
303 {
304 int error, len;
305
306 error = -ENOMEM;
307 len = strlen(name) + strlen(name_prefix) + 2;
308 ls->ls_device.name = kzalloc(len, GFP_KERNEL);
309 if (!ls->ls_device.name)
310 goto fail;
311
312 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
313 name);
314 ls->ls_device.fops = &device_fops;
315 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
316
317 error = misc_register(&ls->ls_device);
318 if (error) {
319 kfree(ls->ls_device.name);
320 }
321 fail:
322 return error;
323 }
324
325 static int device_user_purge(struct dlm_user_proc *proc,
326 struct dlm_purge_params *params)
327 {
328 struct dlm_ls *ls;
329 int error;
330
331 ls = dlm_find_lockspace_local(proc->lockspace);
332 if (!ls)
333 return -ENOENT;
334
335 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
336
337 dlm_put_lockspace(ls);
338 return error;
339 }
340
341 static int device_create_lockspace(struct dlm_lspace_params *params)
342 {
343 dlm_lockspace_t *lockspace;
344 struct dlm_ls *ls;
345 int error;
346
347 if (!capable(CAP_SYS_ADMIN))
348 return -EPERM;
349
350 error = dlm_new_lockspace(params->name, strlen(params->name),
351 &lockspace, 0, DLM_USER_LVB_LEN);
352 if (error)
353 return error;
354
355 ls = dlm_find_lockspace_local(lockspace);
356 if (!ls)
357 return -ENOENT;
358
359 error = create_misc_device(ls, params->name);
360 dlm_put_lockspace(ls);
361
362 if (error)
363 dlm_release_lockspace(lockspace, 0);
364 else
365 error = ls->ls_device.minor;
366
367 return error;
368 }
369
370 static int device_remove_lockspace(struct dlm_lspace_params *params)
371 {
372 dlm_lockspace_t *lockspace;
373 struct dlm_ls *ls;
374 int error, force = 0;
375
376 if (!capable(CAP_SYS_ADMIN))
377 return -EPERM;
378
379 ls = dlm_find_lockspace_device(params->minor);
380 if (!ls)
381 return -ENOENT;
382
383 /* Deregister the misc device first, so we don't have
384 * a device that's not attached to a lockspace. If
385 * dlm_release_lockspace fails then we can recreate it
386 */
387 error = misc_deregister(&ls->ls_device);
388 if (error) {
389 dlm_put_lockspace(ls);
390 goto out;
391 }
392 kfree(ls->ls_device.name);
393
394 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
395 force = 2;
396
397 lockspace = ls->ls_local_handle;
398
399 /* dlm_release_lockspace waits for references to go to zero,
400 so all processes will need to close their device for the ls
401 before the release will procede */
402
403 dlm_put_lockspace(ls);
404 error = dlm_release_lockspace(lockspace, force);
405 if (error)
406 create_misc_device(ls, ls->ls_name);
407 out:
408 return error;
409 }
410
411 /* Check the user's version matches ours */
412 static int check_version(struct dlm_write_request *req)
413 {
414 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
415 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
416 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
417
418 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
419 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
420 current->comm,
421 current->pid,
422 req->version[0],
423 req->version[1],
424 req->version[2],
425 DLM_DEVICE_VERSION_MAJOR,
426 DLM_DEVICE_VERSION_MINOR,
427 DLM_DEVICE_VERSION_PATCH);
428 return -EINVAL;
429 }
430 return 0;
431 }
432
433 /*
434 * device_write
435 *
436 * device_user_lock
437 * dlm_user_request -> request_lock
438 * dlm_user_convert -> convert_lock
439 *
440 * device_user_unlock
441 * dlm_user_unlock -> unlock_lock
442 * dlm_user_cancel -> cancel_lock
443 *
444 * device_create_lockspace
445 * dlm_new_lockspace
446 *
447 * device_remove_lockspace
448 * dlm_release_lockspace
449 */
450
451 /* a write to a lockspace device is a lock or unlock request, a write
452 to the control device is to create/remove a lockspace */
453
454 static ssize_t device_write(struct file *file, const char __user *buf,
455 size_t count, loff_t *ppos)
456 {
457 struct dlm_user_proc *proc = file->private_data;
458 struct dlm_write_request *kbuf;
459 sigset_t tmpsig, allsigs;
460 int error;
461
462 #ifdef CONFIG_COMPAT
463 if (count < sizeof(struct dlm_write_request32))
464 #else
465 if (count < sizeof(struct dlm_write_request))
466 #endif
467 return -EINVAL;
468
469 kbuf = kmalloc(count, GFP_KERNEL);
470 if (!kbuf)
471 return -ENOMEM;
472
473 if (copy_from_user(kbuf, buf, count)) {
474 error = -EFAULT;
475 goto out_free;
476 }
477
478 if (check_version(kbuf)) {
479 error = -EBADE;
480 goto out_free;
481 }
482
483 #ifdef CONFIG_COMPAT
484 if (!kbuf->is64bit) {
485 struct dlm_write_request32 *k32buf;
486 k32buf = (struct dlm_write_request32 *)kbuf;
487 kbuf = kmalloc(count + (sizeof(struct dlm_write_request) -
488 sizeof(struct dlm_write_request32)), GFP_KERNEL);
489 if (!kbuf)
490 return -ENOMEM;
491
492 if (proc)
493 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
494 compat_input(kbuf, k32buf);
495 kfree(k32buf);
496 }
497 #endif
498
499 /* do we really need this? can a write happen after a close? */
500 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
501 test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
502 return -EINVAL;
503
504 sigfillset(&allsigs);
505 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
506
507 error = -EINVAL;
508
509 switch (kbuf->cmd)
510 {
511 case DLM_USER_LOCK:
512 if (!proc) {
513 log_print("no locking on control device");
514 goto out_sig;
515 }
516 error = device_user_lock(proc, &kbuf->i.lock);
517 break;
518
519 case DLM_USER_UNLOCK:
520 if (!proc) {
521 log_print("no locking on control device");
522 goto out_sig;
523 }
524 error = device_user_unlock(proc, &kbuf->i.lock);
525 break;
526
527 case DLM_USER_CREATE_LOCKSPACE:
528 if (proc) {
529 log_print("create/remove only on control device");
530 goto out_sig;
531 }
532 error = device_create_lockspace(&kbuf->i.lspace);
533 break;
534
535 case DLM_USER_REMOVE_LOCKSPACE:
536 if (proc) {
537 log_print("create/remove only on control device");
538 goto out_sig;
539 }
540 error = device_remove_lockspace(&kbuf->i.lspace);
541 break;
542
543 case DLM_USER_PURGE:
544 if (!proc) {
545 log_print("no locking on control device");
546 goto out_sig;
547 }
548 error = device_user_purge(proc, &kbuf->i.purge);
549 break;
550
551 default:
552 log_print("Unknown command passed to DLM device : %d\n",
553 kbuf->cmd);
554 }
555
556 out_sig:
557 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
558 recalc_sigpending();
559 out_free:
560 kfree(kbuf);
561 return error;
562 }
563
564 /* Every process that opens the lockspace device has its own "proc" structure
565 hanging off the open file that's used to keep track of locks owned by the
566 process and asts that need to be delivered to the process. */
567
568 static int device_open(struct inode *inode, struct file *file)
569 {
570 struct dlm_user_proc *proc;
571 struct dlm_ls *ls;
572
573 ls = dlm_find_lockspace_device(iminor(inode));
574 if (!ls)
575 return -ENOENT;
576
577 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
578 if (!proc) {
579 dlm_put_lockspace(ls);
580 return -ENOMEM;
581 }
582
583 proc->lockspace = ls->ls_local_handle;
584 INIT_LIST_HEAD(&proc->asts);
585 INIT_LIST_HEAD(&proc->locks);
586 INIT_LIST_HEAD(&proc->unlocking);
587 spin_lock_init(&proc->asts_spin);
588 spin_lock_init(&proc->locks_spin);
589 init_waitqueue_head(&proc->wait);
590 file->private_data = proc;
591
592 return 0;
593 }
594
595 static int device_close(struct inode *inode, struct file *file)
596 {
597 struct dlm_user_proc *proc = file->private_data;
598 struct dlm_ls *ls;
599 sigset_t tmpsig, allsigs;
600
601 ls = dlm_find_lockspace_local(proc->lockspace);
602 if (!ls)
603 return -ENOENT;
604
605 sigfillset(&allsigs);
606 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
607
608 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
609
610 dlm_clear_proc_locks(ls, proc);
611
612 /* at this point no more lkb's should exist for this lockspace,
613 so there's no chance of dlm_user_add_ast() being called and
614 looking for lkb->ua->proc */
615
616 kfree(proc);
617 file->private_data = NULL;
618
619 dlm_put_lockspace(ls);
620 dlm_put_lockspace(ls); /* for the find in device_open() */
621
622 /* FIXME: AUTOFREE: if this ls is no longer used do
623 device_remove_lockspace() */
624
625 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
626 recalc_sigpending();
627
628 return 0;
629 }
630
631 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type,
632 int bmode, char __user *buf, size_t count)
633 {
634 #ifdef CONFIG_COMPAT
635 struct dlm_lock_result32 result32;
636 #endif
637 struct dlm_lock_result result;
638 void *resultptr;
639 int error=0;
640 int len;
641 int struct_len;
642
643 memset(&result, 0, sizeof(struct dlm_lock_result));
644 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
645 result.user_lksb = ua->user_lksb;
646
647 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
648 in a conversion unless the conversion is successful. See code
649 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
650 notes that a new blocking AST address and parameter are set even if
651 the conversion fails, so maybe we should just do that. */
652
653 if (type == AST_BAST) {
654 result.user_astaddr = ua->bastaddr;
655 result.user_astparam = ua->bastparam;
656 result.bast_mode = bmode;
657 } else {
658 result.user_astaddr = ua->castaddr;
659 result.user_astparam = ua->castparam;
660 }
661
662 #ifdef CONFIG_COMPAT
663 if (compat)
664 len = sizeof(struct dlm_lock_result32);
665 else
666 #endif
667 len = sizeof(struct dlm_lock_result);
668 struct_len = len;
669
670 /* copy lvb to userspace if there is one, it's been updated, and
671 the user buffer has space for it */
672
673 if (ua->update_user_lvb && ua->lksb.sb_lvbptr &&
674 count >= len + DLM_USER_LVB_LEN) {
675 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
676 DLM_USER_LVB_LEN)) {
677 error = -EFAULT;
678 goto out;
679 }
680
681 result.lvb_offset = len;
682 len += DLM_USER_LVB_LEN;
683 }
684
685 result.length = len;
686 resultptr = &result;
687 #ifdef CONFIG_COMPAT
688 if (compat) {
689 compat_output(&result, &result32);
690 resultptr = &result32;
691 }
692 #endif
693
694 if (copy_to_user(buf, resultptr, struct_len))
695 error = -EFAULT;
696 else
697 error = len;
698 out:
699 return error;
700 }
701
702 /* a read returns a single ast described in a struct dlm_lock_result */
703
704 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
705 loff_t *ppos)
706 {
707 struct dlm_user_proc *proc = file->private_data;
708 struct dlm_lkb *lkb;
709 struct dlm_user_args *ua;
710 DECLARE_WAITQUEUE(wait, current);
711 int error, type=0, bmode=0, removed = 0;
712
713 #ifdef CONFIG_COMPAT
714 if (count < sizeof(struct dlm_lock_result32))
715 #else
716 if (count < sizeof(struct dlm_lock_result))
717 #endif
718 return -EINVAL;
719
720 /* do we really need this? can a read happen after a close? */
721 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
722 return -EINVAL;
723
724 spin_lock(&proc->asts_spin);
725 if (list_empty(&proc->asts)) {
726 if (file->f_flags & O_NONBLOCK) {
727 spin_unlock(&proc->asts_spin);
728 return -EAGAIN;
729 }
730
731 add_wait_queue(&proc->wait, &wait);
732
733 repeat:
734 set_current_state(TASK_INTERRUPTIBLE);
735 if (list_empty(&proc->asts) && !signal_pending(current)) {
736 spin_unlock(&proc->asts_spin);
737 schedule();
738 spin_lock(&proc->asts_spin);
739 goto repeat;
740 }
741 set_current_state(TASK_RUNNING);
742 remove_wait_queue(&proc->wait, &wait);
743
744 if (signal_pending(current)) {
745 spin_unlock(&proc->asts_spin);
746 return -ERESTARTSYS;
747 }
748 }
749
750 if (list_empty(&proc->asts)) {
751 spin_unlock(&proc->asts_spin);
752 return -EAGAIN;
753 }
754
755 /* there may be both completion and blocking asts to return for
756 the lkb, don't remove lkb from asts list unless no asts remain */
757
758 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue);
759
760 if (lkb->lkb_ast_type & AST_COMP) {
761 lkb->lkb_ast_type &= ~AST_COMP;
762 type = AST_COMP;
763 } else if (lkb->lkb_ast_type & AST_BAST) {
764 lkb->lkb_ast_type &= ~AST_BAST;
765 type = AST_BAST;
766 bmode = lkb->lkb_bastmode;
767 }
768
769 if (!lkb->lkb_ast_type) {
770 list_del(&lkb->lkb_astqueue);
771 removed = 1;
772 }
773 spin_unlock(&proc->asts_spin);
774
775 ua = (struct dlm_user_args *)lkb->lkb_astparam;
776 error = copy_result_to_user(ua,
777 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
778 type, bmode, buf, count);
779
780 /* removes reference for the proc->asts lists added by
781 dlm_user_add_ast() and may result in the lkb being freed */
782 if (removed)
783 dlm_put_lkb(lkb);
784
785 return error;
786 }
787
788 static unsigned int device_poll(struct file *file, poll_table *wait)
789 {
790 struct dlm_user_proc *proc = file->private_data;
791
792 poll_wait(file, &proc->wait, wait);
793
794 spin_lock(&proc->asts_spin);
795 if (!list_empty(&proc->asts)) {
796 spin_unlock(&proc->asts_spin);
797 return POLLIN | POLLRDNORM;
798 }
799 spin_unlock(&proc->asts_spin);
800 return 0;
801 }
802
803 static int ctl_device_open(struct inode *inode, struct file *file)
804 {
805 file->private_data = NULL;
806 return 0;
807 }
808
809 static int ctl_device_close(struct inode *inode, struct file *file)
810 {
811 return 0;
812 }
813
814 static const struct file_operations device_fops = {
815 .open = device_open,
816 .release = device_close,
817 .read = device_read,
818 .write = device_write,
819 .poll = device_poll,
820 .owner = THIS_MODULE,
821 };
822
823 static const struct file_operations ctl_device_fops = {
824 .open = ctl_device_open,
825 .release = ctl_device_close,
826 .write = device_write,
827 .owner = THIS_MODULE,
828 };
829
830 int dlm_user_init(void)
831 {
832 int error;
833
834 ctl_device.name = "dlm-control";
835 ctl_device.fops = &ctl_device_fops;
836 ctl_device.minor = MISC_DYNAMIC_MINOR;
837
838 error = misc_register(&ctl_device);
839 if (error)
840 log_print("misc_register failed for control device");
841
842 return error;
843 }
844
845 void dlm_user_exit(void)
846 {
847 misc_deregister(&ctl_device);
848 }
849
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