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pid namespaces: destroy pid namespace on init's death
[linux-2.6/mini2440.git] / fs / dlm / user.c
blob6438941ab1f8baf21e4ca88ce5d05b120b525f8b
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 unused;
37 __u32 flags;
38 __u32 lkid;
39 __u32 parent;
40 __u64 xid;
41 __u64 timeout;
42 __u32 castparam;
43 __u32 castaddr;
44 __u32 bastparam;
45 __u32 bastaddr;
46 __u32 lksb;
47 char lvb[DLM_USER_LVB_LEN];
48 char name[0];
49 };
50
51 struct dlm_write_request32 {
52 __u32 version[3];
53 __u8 cmd;
54 __u8 is64bit;
55 __u8 unused[2];
56
57 union {
58 struct dlm_lock_params32 lock;
59 struct dlm_lspace_params lspace;
60 struct dlm_purge_params purge;
61 } i;
62 };
63
64 struct dlm_lksb32 {
65 __u32 sb_status;
66 __u32 sb_lkid;
67 __u8 sb_flags;
68 __u32 sb_lvbptr;
69 };
70
71 struct dlm_lock_result32 {
72 __u32 version[3];
73 __u32 length;
74 __u32 user_astaddr;
75 __u32 user_astparam;
76 __u32 user_lksb;
77 struct dlm_lksb32 lksb;
78 __u8 bast_mode;
79 __u8 unused[3];
80 /* Offsets may be zero if no data is present */
81 __u32 lvb_offset;
82 };
83
84 static void compat_input(struct dlm_write_request *kb,
85 struct dlm_write_request32 *kb32)
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 strcpy(kb->i.lspace.name, kb32->i.lspace.name);
98 } else if (kb->cmd == DLM_USER_PURGE) {
99 kb->i.purge.nodeid = kb32->i.purge.nodeid;
100 kb->i.purge.pid = kb32->i.purge.pid;
101 } else {
102 kb->i.lock.mode = kb32->i.lock.mode;
103 kb->i.lock.namelen = kb32->i.lock.namelen;
104 kb->i.lock.flags = kb32->i.lock.flags;
105 kb->i.lock.lkid = kb32->i.lock.lkid;
106 kb->i.lock.parent = kb32->i.lock.parent;
107 kb->i.lock.xid = kb32->i.lock.xid;
108 kb->i.lock.timeout = kb32->i.lock.timeout;
109 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
110 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
111 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
112 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
113 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
114 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
115 memcpy(kb->i.lock.name, kb32->i.lock.name, kb->i.lock.namelen);
116 }
117 }
118
119 static void compat_output(struct dlm_lock_result *res,
120 struct dlm_lock_result32 *res32)
121 {
122 res32->version[0] = res->version[0];
123 res32->version[1] = res->version[1];
124 res32->version[2] = res->version[2];
125
126 res32->user_astaddr = (__u32)(long)res->user_astaddr;
127 res32->user_astparam = (__u32)(long)res->user_astparam;
128 res32->user_lksb = (__u32)(long)res->user_lksb;
129 res32->bast_mode = res->bast_mode;
130
131 res32->lvb_offset = res->lvb_offset;
132 res32->length = res->length;
133
134 res32->lksb.sb_status = res->lksb.sb_status;
135 res32->lksb.sb_flags = res->lksb.sb_flags;
136 res32->lksb.sb_lkid = res->lksb.sb_lkid;
137 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
138 }
139 #endif
140
141 /* Figure out if this lock is at the end of its life and no longer
142 available for the application to use. The lkb still exists until
143 the final ast is read. A lock becomes EOL in three situations:
144 1. a noqueue request fails with EAGAIN
145 2. an unlock completes with EUNLOCK
146 3. a cancel of a waiting request completes with ECANCEL/EDEADLK
147 An EOL lock needs to be removed from the process's list of locks.
148 And we can't allow any new operation on an EOL lock. This is
149 not related to the lifetime of the lkb struct which is managed
150 entirely by refcount. */
151
152 static int lkb_is_endoflife(struct dlm_lkb *lkb, int sb_status, int type)
153 {
154 switch (sb_status) {
155 case -DLM_EUNLOCK:
156 return 1;
157 case -DLM_ECANCEL:
158 case -ETIMEDOUT:
159 case -EDEADLK:
160 if (lkb->lkb_grmode == DLM_LOCK_IV)
161 return 1;
162 break;
163 case -EAGAIN:
164 if (type == AST_COMP && lkb->lkb_grmode == DLM_LOCK_IV)
165 return 1;
166 break;
167 }
168 return 0;
169 }
170
171 /* we could possibly check if the cancel of an orphan has resulted in the lkb
172 being removed and then remove that lkb from the orphans list and free it */
173
174 void dlm_user_add_ast(struct dlm_lkb *lkb, int type)
175 {
176 struct dlm_ls *ls;
177 struct dlm_user_args *ua;
178 struct dlm_user_proc *proc;
179 int eol = 0, ast_type;
180
181 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
182 return;
183
184 ls = lkb->lkb_resource->res_ls;
185 mutex_lock(&ls->ls_clear_proc_locks);
186
187 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
188 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed
189 lkb->ua so we can't try to use it. This second check is necessary
190 for cases where a completion ast is received for an operation that
191 began before clear_proc_locks did its cancel/unlock. */
192
193 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
194 goto out;
195
196 DLM_ASSERT(lkb->lkb_astparam, dlm_print_lkb(lkb););
197 ua = (struct dlm_user_args *)lkb->lkb_astparam;
198 proc = ua->proc;
199
200 if (type == AST_BAST && ua->bastaddr == NULL)
201 goto out;
202
203 spin_lock(&proc->asts_spin);
204
205 ast_type = lkb->lkb_ast_type;
206 lkb->lkb_ast_type |= type;
207
208 if (!ast_type) {
209 kref_get(&lkb->lkb_ref);
210 list_add_tail(&lkb->lkb_astqueue, &proc->asts);
211 wake_up_interruptible(&proc->wait);
212 }
213 if (type == AST_COMP && (ast_type & AST_COMP))
214 log_debug(ls, "ast overlap %x status %x %x",
215 lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags);
216
217 eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type);
218 if (eol) {
219 lkb->lkb_ast_type &= ~AST_BAST;
220 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
221 }
222
223 /* We want to copy the lvb to userspace when the completion
224 ast is read if the status is 0, the lock has an lvb and
225 lvb_ops says we should. We could probably have set_lvb_lock()
226 set update_user_lvb instead and not need old_mode */
227
228 if ((lkb->lkb_ast_type & AST_COMP) &&
229 (lkb->lkb_lksb->sb_status == 0) &&
230 lkb->lkb_lksb->sb_lvbptr &&
231 dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1])
232 ua->update_user_lvb = 1;
233 else
234 ua->update_user_lvb = 0;
235
236 spin_unlock(&proc->asts_spin);
237
238 if (eol) {
239 spin_lock(&ua->proc->locks_spin);
240 if (!list_empty(&lkb->lkb_ownqueue)) {
241 list_del_init(&lkb->lkb_ownqueue);
242 dlm_put_lkb(lkb);
243 }
244 spin_unlock(&ua->proc->locks_spin);
245 }
246 out:
247 mutex_unlock(&ls->ls_clear_proc_locks);
248 }
249
250 static int device_user_lock(struct dlm_user_proc *proc,
251 struct dlm_lock_params *params)
252 {
253 struct dlm_ls *ls;
254 struct dlm_user_args *ua;
255 int error = -ENOMEM;
256
257 ls = dlm_find_lockspace_local(proc->lockspace);
258 if (!ls)
259 return -ENOENT;
260
261 if (!params->castaddr || !params->lksb) {
262 error = -EINVAL;
263 goto out;
264 }
265
266 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
267 if (!ua)
268 goto out;
269 ua->proc = proc;
270 ua->user_lksb = params->lksb;
271 ua->castparam = params->castparam;
272 ua->castaddr = params->castaddr;
273 ua->bastparam = params->bastparam;
274 ua->bastaddr = params->bastaddr;
275 ua->xid = params->xid;
276
277 if (params->flags & DLM_LKF_CONVERT)
278 error = dlm_user_convert(ls, ua,
279 params->mode, params->flags,
280 params->lkid, params->lvb,
281 (unsigned long) params->timeout);
282 else {
283 error = dlm_user_request(ls, ua,
284 params->mode, params->flags,
285 params->name, params->namelen,
286 (unsigned long) params->timeout);
287 if (!error)
288 error = ua->lksb.sb_lkid;
289 }
290 out:
291 dlm_put_lockspace(ls);
292 return error;
293 }
294
295 static int device_user_unlock(struct dlm_user_proc *proc,
296 struct dlm_lock_params *params)
297 {
298 struct dlm_ls *ls;
299 struct dlm_user_args *ua;
300 int error = -ENOMEM;
301
302 ls = dlm_find_lockspace_local(proc->lockspace);
303 if (!ls)
304 return -ENOENT;
305
306 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
307 if (!ua)
308 goto out;
309 ua->proc = proc;
310 ua->user_lksb = params->lksb;
311 ua->castparam = params->castparam;
312 ua->castaddr = params->castaddr;
313
314 if (params->flags & DLM_LKF_CANCEL)
315 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
316 else
317 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
318 params->lvb);
319 out:
320 dlm_put_lockspace(ls);
321 return error;
322 }
323
324 static int device_user_deadlock(struct dlm_user_proc *proc,
325 struct dlm_lock_params *params)
326 {
327 struct dlm_ls *ls;
328 int error;
329
330 ls = dlm_find_lockspace_local(proc->lockspace);
331 if (!ls)
332 return -ENOENT;
333
334 error = dlm_user_deadlock(ls, params->flags, params->lkid);
335
336 dlm_put_lockspace(ls);
337 return error;
338 }
339
340 static int create_misc_device(struct dlm_ls *ls, char *name)
341 {
342 int error, len;
343
344 error = -ENOMEM;
345 len = strlen(name) + strlen(name_prefix) + 2;
346 ls->ls_device.name = kzalloc(len, GFP_KERNEL);
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 static int device_user_purge(struct dlm_user_proc *proc,
364 struct dlm_purge_params *params)
365 {
366 struct dlm_ls *ls;
367 int error;
368
369 ls = dlm_find_lockspace_local(proc->lockspace);
370 if (!ls)
371 return -ENOENT;
372
373 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
374
375 dlm_put_lockspace(ls);
376 return error;
377 }
378
379 static int device_create_lockspace(struct dlm_lspace_params *params)
380 {
381 dlm_lockspace_t *lockspace;
382 struct dlm_ls *ls;
383 int error;
384
385 if (!capable(CAP_SYS_ADMIN))
386 return -EPERM;
387
388 error = dlm_new_lockspace(params->name, strlen(params->name),
389 &lockspace, params->flags, DLM_USER_LVB_LEN);
390 if (error)
391 return error;
392
393 ls = dlm_find_lockspace_local(lockspace);
394 if (!ls)
395 return -ENOENT;
396
397 error = create_misc_device(ls, params->name);
398 dlm_put_lockspace(ls);
399
400 if (error)
401 dlm_release_lockspace(lockspace, 0);
402 else
403 error = ls->ls_device.minor;
404
405 return error;
406 }
407
408 static int device_remove_lockspace(struct dlm_lspace_params *params)
409 {
410 dlm_lockspace_t *lockspace;
411 struct dlm_ls *ls;
412 int error, force = 0;
413
414 if (!capable(CAP_SYS_ADMIN))
415 return -EPERM;
416
417 ls = dlm_find_lockspace_device(params->minor);
418 if (!ls)
419 return -ENOENT;
420
421 /* Deregister the misc device first, so we don't have
422 * a device that's not attached to a lockspace. If
423 * dlm_release_lockspace fails then we can recreate it
424 */
425 error = misc_deregister(&ls->ls_device);
426 if (error) {
427 dlm_put_lockspace(ls);
428 goto out;
429 }
430 kfree(ls->ls_device.name);
431
432 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
433 force = 2;
434
435 lockspace = ls->ls_local_handle;
436
437 /* dlm_release_lockspace waits for references to go to zero,
438 so all processes will need to close their device for the ls
439 before the release will procede */
440
441 dlm_put_lockspace(ls);
442 error = dlm_release_lockspace(lockspace, force);
443 if (error)
444 create_misc_device(ls, ls->ls_name);
445 out:
446 return error;
447 }
448
449 /* Check the user's version matches ours */
450 static int check_version(struct dlm_write_request *req)
451 {
452 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
453 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
454 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
455
456 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
457 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
458 current->comm,
459 current->pid,
460 req->version[0],
461 req->version[1],
462 req->version[2],
463 DLM_DEVICE_VERSION_MAJOR,
464 DLM_DEVICE_VERSION_MINOR,
465 DLM_DEVICE_VERSION_PATCH);
466 return -EINVAL;
467 }
468 return 0;
469 }
470
471 /*
472 * device_write
473 *
474 * device_user_lock
475 * dlm_user_request -> request_lock
476 * dlm_user_convert -> convert_lock
477 *
478 * device_user_unlock
479 * dlm_user_unlock -> unlock_lock
480 * dlm_user_cancel -> cancel_lock
481 *
482 * device_create_lockspace
483 * dlm_new_lockspace
484 *
485 * device_remove_lockspace
486 * dlm_release_lockspace
487 */
488
489 /* a write to a lockspace device is a lock or unlock request, a write
490 to the control device is to create/remove a lockspace */
491
492 static ssize_t device_write(struct file *file, const char __user *buf,
493 size_t count, loff_t *ppos)
494 {
495 struct dlm_user_proc *proc = file->private_data;
496 struct dlm_write_request *kbuf;
497 sigset_t tmpsig, allsigs;
498 int error;
499
500 #ifdef CONFIG_COMPAT
501 if (count < sizeof(struct dlm_write_request32))
502 #else
503 if (count < sizeof(struct dlm_write_request))
504 #endif
505 return -EINVAL;
506
507 kbuf = kmalloc(count, GFP_KERNEL);
508 if (!kbuf)
509 return -ENOMEM;
510
511 if (copy_from_user(kbuf, buf, count)) {
512 error = -EFAULT;
513 goto out_free;
514 }
515
516 if (check_version(kbuf)) {
517 error = -EBADE;
518 goto out_free;
519 }
520
521 #ifdef CONFIG_COMPAT
522 if (!kbuf->is64bit) {
523 struct dlm_write_request32 *k32buf;
524 k32buf = (struct dlm_write_request32 *)kbuf;
525 kbuf = kmalloc(count + (sizeof(struct dlm_write_request) -
526 sizeof(struct dlm_write_request32)), GFP_KERNEL);
527 if (!kbuf)
528 return -ENOMEM;
529
530 if (proc)
531 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
532 compat_input(kbuf, k32buf);
533 kfree(k32buf);
534 }
535 #endif
536
537 /* do we really need this? can a write happen after a close? */
538 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
539 test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
540 return -EINVAL;
541
542 sigfillset(&allsigs);
543 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
544
545 error = -EINVAL;
546
547 switch (kbuf->cmd)
548 {
549 case DLM_USER_LOCK:
550 if (!proc) {
551 log_print("no locking on control device");
552 goto out_sig;
553 }
554 error = device_user_lock(proc, &kbuf->i.lock);
555 break;
556
557 case DLM_USER_UNLOCK:
558 if (!proc) {
559 log_print("no locking on control device");
560 goto out_sig;
561 }
562 error = device_user_unlock(proc, &kbuf->i.lock);
563 break;
564
565 case DLM_USER_DEADLOCK:
566 if (!proc) {
567 log_print("no locking on control device");
568 goto out_sig;
569 }
570 error = device_user_deadlock(proc, &kbuf->i.lock);
571 break;
572
573 case DLM_USER_CREATE_LOCKSPACE:
574 if (proc) {
575 log_print("create/remove only on control device");
576 goto out_sig;
577 }
578 error = device_create_lockspace(&kbuf->i.lspace);
579 break;
580
581 case DLM_USER_REMOVE_LOCKSPACE:
582 if (proc) {
583 log_print("create/remove only on control device");
584 goto out_sig;
585 }
586 error = device_remove_lockspace(&kbuf->i.lspace);
587 break;
588
589 case DLM_USER_PURGE:
590 if (!proc) {
591 log_print("no locking on control device");
592 goto out_sig;
593 }
594 error = device_user_purge(proc, &kbuf->i.purge);
595 break;
596
597 default:
598 log_print("Unknown command passed to DLM device : %d\n",
599 kbuf->cmd);
600 }
601
602 out_sig:
603 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
604 recalc_sigpending();
605 out_free:
606 kfree(kbuf);
607 return error;
608 }
609
610 /* Every process that opens the lockspace device has its own "proc" structure
611 hanging off the open file that's used to keep track of locks owned by the
612 process and asts that need to be delivered to the process. */
613
614 static int device_open(struct inode *inode, struct file *file)
615 {
616 struct dlm_user_proc *proc;
617 struct dlm_ls *ls;
618
619 ls = dlm_find_lockspace_device(iminor(inode));
620 if (!ls)
621 return -ENOENT;
622
623 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
624 if (!proc) {
625 dlm_put_lockspace(ls);
626 return -ENOMEM;
627 }
628
629 proc->lockspace = ls->ls_local_handle;
630 INIT_LIST_HEAD(&proc->asts);
631 INIT_LIST_HEAD(&proc->locks);
632 INIT_LIST_HEAD(&proc->unlocking);
633 spin_lock_init(&proc->asts_spin);
634 spin_lock_init(&proc->locks_spin);
635 init_waitqueue_head(&proc->wait);
636 file->private_data = proc;
637
638 return 0;
639 }
640
641 static int device_close(struct inode *inode, struct file *file)
642 {
643 struct dlm_user_proc *proc = file->private_data;
644 struct dlm_ls *ls;
645 sigset_t tmpsig, allsigs;
646
647 ls = dlm_find_lockspace_local(proc->lockspace);
648 if (!ls)
649 return -ENOENT;
650
651 sigfillset(&allsigs);
652 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
653
654 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
655
656 dlm_clear_proc_locks(ls, proc);
657
658 /* at this point no more lkb's should exist for this lockspace,
659 so there's no chance of dlm_user_add_ast() being called and
660 looking for lkb->ua->proc */
661
662 kfree(proc);
663 file->private_data = NULL;
664
665 dlm_put_lockspace(ls);
666 dlm_put_lockspace(ls); /* for the find in device_open() */
667
668 /* FIXME: AUTOFREE: if this ls is no longer used do
669 device_remove_lockspace() */
670
671 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
672 recalc_sigpending();
673
674 return 0;
675 }
676
677 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type,
678 int bmode, char __user *buf, size_t count)
679 {
680 #ifdef CONFIG_COMPAT
681 struct dlm_lock_result32 result32;
682 #endif
683 struct dlm_lock_result result;
684 void *resultptr;
685 int error=0;
686 int len;
687 int struct_len;
688
689 memset(&result, 0, sizeof(struct dlm_lock_result));
690 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
691 result.version[1] = DLM_DEVICE_VERSION_MINOR;
692 result.version[2] = DLM_DEVICE_VERSION_PATCH;
693 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
694 result.user_lksb = ua->user_lksb;
695
696 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
697 in a conversion unless the conversion is successful. See code
698 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
699 notes that a new blocking AST address and parameter are set even if
700 the conversion fails, so maybe we should just do that. */
701
702 if (type == AST_BAST) {
703 result.user_astaddr = ua->bastaddr;
704 result.user_astparam = ua->bastparam;
705 result.bast_mode = bmode;
706 } else {
707 result.user_astaddr = ua->castaddr;
708 result.user_astparam = ua->castparam;
709 }
710
711 #ifdef CONFIG_COMPAT
712 if (compat)
713 len = sizeof(struct dlm_lock_result32);
714 else
715 #endif
716 len = sizeof(struct dlm_lock_result);
717 struct_len = len;
718
719 /* copy lvb to userspace if there is one, it's been updated, and
720 the user buffer has space for it */
721
722 if (ua->update_user_lvb && ua->lksb.sb_lvbptr &&
723 count >= len + DLM_USER_LVB_LEN) {
724 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
725 DLM_USER_LVB_LEN)) {
726 error = -EFAULT;
727 goto out;
728 }
729
730 result.lvb_offset = len;
731 len += DLM_USER_LVB_LEN;
732 }
733
734 result.length = len;
735 resultptr = &result;
736 #ifdef CONFIG_COMPAT
737 if (compat) {
738 compat_output(&result, &result32);
739 resultptr = &result32;
740 }
741 #endif
742
743 if (copy_to_user(buf, resultptr, struct_len))
744 error = -EFAULT;
745 else
746 error = len;
747 out:
748 return error;
749 }
750
751 static int copy_version_to_user(char __user *buf, size_t count)
752 {
753 struct dlm_device_version ver;
754
755 memset(&ver, 0, sizeof(struct dlm_device_version));
756 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
757 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
758 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
759
760 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
761 return -EFAULT;
762 return sizeof(struct dlm_device_version);
763 }
764
765 /* a read returns a single ast described in a struct dlm_lock_result */
766
767 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
768 loff_t *ppos)
769 {
770 struct dlm_user_proc *proc = file->private_data;
771 struct dlm_lkb *lkb;
772 struct dlm_user_args *ua;
773 DECLARE_WAITQUEUE(wait, current);
774 int error, type=0, bmode=0, removed = 0;
775
776 if (count == sizeof(struct dlm_device_version)) {
777 error = copy_version_to_user(buf, count);
778 return error;
779 }
780
781 if (!proc) {
782 log_print("non-version read from control device %zu", count);
783 return -EINVAL;
784 }
785
786 #ifdef CONFIG_COMPAT
787 if (count < sizeof(struct dlm_lock_result32))
788 #else
789 if (count < sizeof(struct dlm_lock_result))
790 #endif
791 return -EINVAL;
792
793 /* do we really need this? can a read happen after a close? */
794 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
795 return -EINVAL;
796
797 spin_lock(&proc->asts_spin);
798 if (list_empty(&proc->asts)) {
799 if (file->f_flags & O_NONBLOCK) {
800 spin_unlock(&proc->asts_spin);
801 return -EAGAIN;
802 }
803
804 add_wait_queue(&proc->wait, &wait);
805
806 repeat:
807 set_current_state(TASK_INTERRUPTIBLE);
808 if (list_empty(&proc->asts) && !signal_pending(current)) {
809 spin_unlock(&proc->asts_spin);
810 schedule();
811 spin_lock(&proc->asts_spin);
812 goto repeat;
813 }
814 set_current_state(TASK_RUNNING);
815 remove_wait_queue(&proc->wait, &wait);
816
817 if (signal_pending(current)) {
818 spin_unlock(&proc->asts_spin);
819 return -ERESTARTSYS;
820 }
821 }
822
823 /* there may be both completion and blocking asts to return for
824 the lkb, don't remove lkb from asts list unless no asts remain */
825
826 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue);
827
828 if (lkb->lkb_ast_type & AST_COMP) {
829 lkb->lkb_ast_type &= ~AST_COMP;
830 type = AST_COMP;
831 } else if (lkb->lkb_ast_type & AST_BAST) {
832 lkb->lkb_ast_type &= ~AST_BAST;
833 type = AST_BAST;
834 bmode = lkb->lkb_bastmode;
835 }
836
837 if (!lkb->lkb_ast_type) {
838 list_del(&lkb->lkb_astqueue);
839 removed = 1;
840 }
841 spin_unlock(&proc->asts_spin);
842
843 ua = (struct dlm_user_args *)lkb->lkb_astparam;
844 error = copy_result_to_user(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 int dlm_user_init(void)
900 {
901 int error;
902
903 ctl_device.name = "dlm-control";
904 ctl_device.fops = &ctl_device_fops;
905 ctl_device.minor = MISC_DYNAMIC_MINOR;
906
907 error = misc_register(&ctl_device);
908 if (error)
909 log_print("misc_register failed for control device");
910
911 return error;
912 }
913
914 void dlm_user_exit(void)
915 {
916 misc_deregister(&ctl_device);
917 }
918
Support for the Chinese Samsung S3C2440 based development boards