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/file.h>
13 #include <linux/fs.h>
14 #include <linux/poll.h>
15 #include <linux/signal.h>
16 #include <linux/spinlock.h>
17 #include <linux/dlm.h>
18 #include <linux/dlm_device.h>
19 #include <linux/slab.h>
20 #include <linux/sched/signal.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 #include "config.h"
29
30 static const char name_prefix[] = "dlm";
31 static const struct file_operations device_fops;
32 static atomic_t dlm_monitor_opened;
33 static int dlm_monitor_unused = 1;
34
35 #ifdef CONFIG_COMPAT
36
37 struct dlm_lock_params32 {
38 __u8 mode;
39 __u8 namelen;
40 __u16 unused;
41 __u32 flags;
42 __u32 lkid;
43 __u32 parent;
44 __u64 xid;
45 __u64 timeout;
46 __u32 castparam;
47 __u32 castaddr;
48 __u32 bastparam;
49 __u32 bastaddr;
50 __u32 lksb;
51 char lvb[DLM_USER_LVB_LEN];
52 char name[0];
53 };
54
55 struct dlm_write_request32 {
56 __u32 version[3];
57 __u8 cmd;
58 __u8 is64bit;
59 __u8 unused[2];
60
61 union {
62 struct dlm_lock_params32 lock;
63 struct dlm_lspace_params lspace;
64 struct dlm_purge_params purge;
65 } i;
66 };
67
68 struct dlm_lksb32 {
69 __u32 sb_status;
70 __u32 sb_lkid;
71 __u8 sb_flags;
72 __u32 sb_lvbptr;
73 };
74
75 struct dlm_lock_result32 {
76 __u32 version[3];
77 __u32 length;
78 __u32 user_astaddr;
79 __u32 user_astparam;
80 __u32 user_lksb;
81 struct dlm_lksb32 lksb;
82 __u8 bast_mode;
83 __u8 unused[3];
84 /* Offsets may be zero if no data is present */
85 __u32 lvb_offset;
86 };
87
compat_input(struct dlm_write_request * kb,struct dlm_write_request32 * kb32,int namelen)88 static void compat_input(struct dlm_write_request *kb,
89 struct dlm_write_request32 *kb32,
90 int namelen)
91 {
92 kb->version[0] = kb32->version[0];
93 kb->version[1] = kb32->version[1];
94 kb->version[2] = kb32->version[2];
95
96 kb->cmd = kb32->cmd;
97 kb->is64bit = kb32->is64bit;
98 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
99 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
100 kb->i.lspace.flags = kb32->i.lspace.flags;
101 kb->i.lspace.minor = kb32->i.lspace.minor;
102 memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
103 } else if (kb->cmd == DLM_USER_PURGE) {
104 kb->i.purge.nodeid = kb32->i.purge.nodeid;
105 kb->i.purge.pid = kb32->i.purge.pid;
106 } else {
107 kb->i.lock.mode = kb32->i.lock.mode;
108 kb->i.lock.namelen = kb32->i.lock.namelen;
109 kb->i.lock.flags = kb32->i.lock.flags;
110 kb->i.lock.lkid = kb32->i.lock.lkid;
111 kb->i.lock.parent = kb32->i.lock.parent;
112 kb->i.lock.xid = kb32->i.lock.xid;
113 kb->i.lock.timeout = kb32->i.lock.timeout;
114 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
115 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
116 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
117 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
118 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
119 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
120 memcpy(kb->i.lock.name, kb32->i.lock.name, namelen);
121 }
122 }
123
compat_output(struct dlm_lock_result * res,struct dlm_lock_result32 * res32)124 static void compat_output(struct dlm_lock_result *res,
125 struct dlm_lock_result32 *res32)
126 {
127 memset(res32, 0, sizeof(*res32));
128
129 res32->version[0] = res->version[0];
130 res32->version[1] = res->version[1];
131 res32->version[2] = res->version[2];
132
133 res32->user_astaddr = (__u32)(long)res->user_astaddr;
134 res32->user_astparam = (__u32)(long)res->user_astparam;
135 res32->user_lksb = (__u32)(long)res->user_lksb;
136 res32->bast_mode = res->bast_mode;
137
138 res32->lvb_offset = res->lvb_offset;
139 res32->length = res->length;
140
141 res32->lksb.sb_status = res->lksb.sb_status;
142 res32->lksb.sb_flags = res->lksb.sb_flags;
143 res32->lksb.sb_lkid = res->lksb.sb_lkid;
144 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
145 }
146 #endif
147
148 /* Figure out if this lock is at the end of its life and no longer
149 available for the application to use. The lkb still exists until
150 the final ast is read. A lock becomes EOL in three situations:
151 1. a noqueue request fails with EAGAIN
152 2. an unlock completes with EUNLOCK
153 3. a cancel of a waiting request completes with ECANCEL/EDEADLK
154 An EOL lock needs to be removed from the process's list of locks.
155 And we can't allow any new operation on an EOL lock. This is
156 not related to the lifetime of the lkb struct which is managed
157 entirely by refcount. */
158
lkb_is_endoflife(int mode,int status)159 static int lkb_is_endoflife(int mode, int status)
160 {
161 switch (status) {
162 case -DLM_EUNLOCK:
163 return 1;
164 case -DLM_ECANCEL:
165 case -ETIMEDOUT:
166 case -EDEADLK:
167 case -EAGAIN:
168 if (mode == DLM_LOCK_IV)
169 return 1;
170 break;
171 }
172 return 0;
173 }
174
175 /* we could possibly check if the cancel of an orphan has resulted in the lkb
176 being removed and then remove that lkb from the orphans list and free it */
177
dlm_user_add_ast(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags,uint64_t seq)178 void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode,
179 int status, uint32_t sbflags, uint64_t seq)
180 {
181 struct dlm_ls *ls;
182 struct dlm_user_args *ua;
183 struct dlm_user_proc *proc;
184 int rv;
185
186 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
187 return;
188
189 ls = lkb->lkb_resource->res_ls;
190 mutex_lock(&ls->ls_clear_proc_locks);
191
192 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
193 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed
194 lkb->ua so we can't try to use it. This second check is necessary
195 for cases where a completion ast is received for an operation that
196 began before clear_proc_locks did its cancel/unlock. */
197
198 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
199 goto out;
200
201 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
202 ua = lkb->lkb_ua;
203 proc = ua->proc;
204
205 if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL)
206 goto out;
207
208 if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status))
209 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
210
211 spin_lock(&proc->asts_spin);
212
213 rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq);
214 if (rv < 0) {
215 spin_unlock(&proc->asts_spin);
216 goto out;
217 }
218
219 if (list_empty(&lkb->lkb_cb_list)) {
220 kref_get(&lkb->lkb_ref);
221 list_add_tail(&lkb->lkb_cb_list, &proc->asts);
222 wake_up_interruptible(&proc->wait);
223 }
224 spin_unlock(&proc->asts_spin);
225
226 if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) {
227 /* N.B. spin_lock locks_spin, not asts_spin */
228 spin_lock(&proc->locks_spin);
229 if (!list_empty(&lkb->lkb_ownqueue)) {
230 list_del_init(&lkb->lkb_ownqueue);
231 dlm_put_lkb(lkb);
232 }
233 spin_unlock(&proc->locks_spin);
234 }
235 out:
236 mutex_unlock(&ls->ls_clear_proc_locks);
237 }
238
device_user_lock(struct dlm_user_proc * proc,struct dlm_lock_params * params)239 static int device_user_lock(struct dlm_user_proc *proc,
240 struct dlm_lock_params *params)
241 {
242 struct dlm_ls *ls;
243 struct dlm_user_args *ua;
244 uint32_t lkid;
245 int error = -ENOMEM;
246
247 ls = dlm_find_lockspace_local(proc->lockspace);
248 if (!ls)
249 return -ENOENT;
250
251 if (!params->castaddr || !params->lksb) {
252 error = -EINVAL;
253 goto out;
254 }
255
256 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
257 if (!ua)
258 goto out;
259 ua->proc = proc;
260 ua->user_lksb = params->lksb;
261 ua->castparam = params->castparam;
262 ua->castaddr = params->castaddr;
263 ua->bastparam = params->bastparam;
264 ua->bastaddr = params->bastaddr;
265 ua->xid = params->xid;
266
267 if (params->flags & DLM_LKF_CONVERT) {
268 error = dlm_user_convert(ls, ua,
269 params->mode, params->flags,
270 params->lkid, params->lvb,
271 (unsigned long) params->timeout);
272 } else if (params->flags & DLM_LKF_ORPHAN) {
273 error = dlm_user_adopt_orphan(ls, ua,
274 params->mode, params->flags,
275 params->name, params->namelen,
276 (unsigned long) params->timeout,
277 &lkid);
278 if (!error)
279 error = lkid;
280 } else {
281 error = dlm_user_request(ls, ua,
282 params->mode, params->flags,
283 params->name, params->namelen,
284 (unsigned long) params->timeout);
285 if (!error)
286 error = ua->lksb.sb_lkid;
287 }
288 out:
289 dlm_put_lockspace(ls);
290 return error;
291 }
292
device_user_unlock(struct dlm_user_proc * proc,struct dlm_lock_params * params)293 static int device_user_unlock(struct dlm_user_proc *proc,
294 struct dlm_lock_params *params)
295 {
296 struct dlm_ls *ls;
297 struct dlm_user_args *ua;
298 int error = -ENOMEM;
299
300 ls = dlm_find_lockspace_local(proc->lockspace);
301 if (!ls)
302 return -ENOENT;
303
304 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
305 if (!ua)
306 goto out;
307 ua->proc = proc;
308 ua->user_lksb = params->lksb;
309 ua->castparam = params->castparam;
310 ua->castaddr = params->castaddr;
311
312 if (params->flags & DLM_LKF_CANCEL)
313 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
314 else
315 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
316 params->lvb);
317 out:
318 dlm_put_lockspace(ls);
319 return error;
320 }
321
device_user_deadlock(struct dlm_user_proc * proc,struct dlm_lock_params * params)322 static int device_user_deadlock(struct dlm_user_proc *proc,
323 struct dlm_lock_params *params)
324 {
325 struct dlm_ls *ls;
326 int error;
327
328 ls = dlm_find_lockspace_local(proc->lockspace);
329 if (!ls)
330 return -ENOENT;
331
332 error = dlm_user_deadlock(ls, params->flags, params->lkid);
333
334 dlm_put_lockspace(ls);
335 return error;
336 }
337
dlm_device_register(struct dlm_ls * ls,char * name)338 static int dlm_device_register(struct dlm_ls *ls, char *name)
339 {
340 int error, len;
341
342 /* The device is already registered. This happens when the
343 lockspace is created multiple times from userspace. */
344 if (ls->ls_device.name)
345 return 0;
346
347 error = -ENOMEM;
348 len = strlen(name) + strlen(name_prefix) + 2;
349 ls->ls_device.name = kzalloc(len, GFP_NOFS);
350 if (!ls->ls_device.name)
351 goto fail;
352
353 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
354 name);
355 ls->ls_device.fops = &device_fops;
356 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
357
358 error = misc_register(&ls->ls_device);
359 if (error) {
360 kfree(ls->ls_device.name);
361 /* this has to be set to NULL
362 * to avoid a double-free in dlm_device_deregister
363 */
364 ls->ls_device.name = NULL;
365 }
366 fail:
367 return error;
368 }
369
dlm_device_deregister(struct dlm_ls * ls)370 int dlm_device_deregister(struct dlm_ls *ls)
371 {
372 /* The device is not registered. This happens when the lockspace
373 was never used from userspace, or when device_create_lockspace()
374 calls dlm_release_lockspace() after the register fails. */
375 if (!ls->ls_device.name)
376 return 0;
377
378 misc_deregister(&ls->ls_device);
379 kfree(ls->ls_device.name);
380 return 0;
381 }
382
device_user_purge(struct dlm_user_proc * proc,struct dlm_purge_params * params)383 static int device_user_purge(struct dlm_user_proc *proc,
384 struct dlm_purge_params *params)
385 {
386 struct dlm_ls *ls;
387 int error;
388
389 ls = dlm_find_lockspace_local(proc->lockspace);
390 if (!ls)
391 return -ENOENT;
392
393 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
394
395 dlm_put_lockspace(ls);
396 return error;
397 }
398
device_create_lockspace(struct dlm_lspace_params * params)399 static int device_create_lockspace(struct dlm_lspace_params *params)
400 {
401 dlm_lockspace_t *lockspace;
402 struct dlm_ls *ls;
403 int error;
404
405 if (!capable(CAP_SYS_ADMIN))
406 return -EPERM;
407
408 error = dlm_new_lockspace(params->name, dlm_config.ci_cluster_name, params->flags,
409 DLM_USER_LVB_LEN, NULL, NULL, NULL,
410 &lockspace);
411 if (error)
412 return error;
413
414 ls = dlm_find_lockspace_local(lockspace);
415 if (!ls)
416 return -ENOENT;
417
418 error = dlm_device_register(ls, params->name);
419 dlm_put_lockspace(ls);
420
421 if (error)
422 dlm_release_lockspace(lockspace, 0);
423 else
424 error = ls->ls_device.minor;
425
426 return error;
427 }
428
device_remove_lockspace(struct dlm_lspace_params * params)429 static int device_remove_lockspace(struct dlm_lspace_params *params)
430 {
431 dlm_lockspace_t *lockspace;
432 struct dlm_ls *ls;
433 int error, force = 0;
434
435 if (!capable(CAP_SYS_ADMIN))
436 return -EPERM;
437
438 ls = dlm_find_lockspace_device(params->minor);
439 if (!ls)
440 return -ENOENT;
441
442 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
443 force = 2;
444
445 lockspace = ls->ls_local_handle;
446 dlm_put_lockspace(ls);
447
448 /* The final dlm_release_lockspace waits for references to go to
449 zero, so all processes will need to close their device for the
450 ls before the release will proceed. release also calls the
451 device_deregister above. Converting a positive return value
452 from release to zero means that userspace won't know when its
453 release was the final one, but it shouldn't need to know. */
454
455 error = dlm_release_lockspace(lockspace, force);
456 if (error > 0)
457 error = 0;
458 return error;
459 }
460
461 /* Check the user's version matches ours */
check_version(struct dlm_write_request * req)462 static int check_version(struct dlm_write_request *req)
463 {
464 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
465 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
466 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
467
468 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
469 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
470 current->comm,
471 task_pid_nr(current),
472 req->version[0],
473 req->version[1],
474 req->version[2],
475 DLM_DEVICE_VERSION_MAJOR,
476 DLM_DEVICE_VERSION_MINOR,
477 DLM_DEVICE_VERSION_PATCH);
478 return -EINVAL;
479 }
480 return 0;
481 }
482
483 /*
484 * device_write
485 *
486 * device_user_lock
487 * dlm_user_request -> request_lock
488 * dlm_user_convert -> convert_lock
489 *
490 * device_user_unlock
491 * dlm_user_unlock -> unlock_lock
492 * dlm_user_cancel -> cancel_lock
493 *
494 * device_create_lockspace
495 * dlm_new_lockspace
496 *
497 * device_remove_lockspace
498 * dlm_release_lockspace
499 */
500
501 /* a write to a lockspace device is a lock or unlock request, a write
502 to the control device is to create/remove a lockspace */
503
device_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)504 static ssize_t device_write(struct file *file, const char __user *buf,
505 size_t count, loff_t *ppos)
506 {
507 struct dlm_user_proc *proc = file->private_data;
508 struct dlm_write_request *kbuf;
509 int error;
510
511 #ifdef CONFIG_COMPAT
512 if (count < sizeof(struct dlm_write_request32))
513 #else
514 if (count < sizeof(struct dlm_write_request))
515 #endif
516 return -EINVAL;
517
518 /*
519 * can't compare against COMPAT/dlm_write_request32 because
520 * we don't yet know if is64bit is zero
521 */
522 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
523 return -EINVAL;
524
525 kbuf = memdup_user_nul(buf, count);
526 if (IS_ERR(kbuf))
527 return PTR_ERR(kbuf);
528
529 if (check_version(kbuf)) {
530 error = -EBADE;
531 goto out_free;
532 }
533
534 #ifdef CONFIG_COMPAT
535 if (!kbuf->is64bit) {
536 struct dlm_write_request32 *k32buf;
537 int namelen = 0;
538
539 if (count > sizeof(struct dlm_write_request32))
540 namelen = count - sizeof(struct dlm_write_request32);
541
542 k32buf = (struct dlm_write_request32 *)kbuf;
543
544 /* add 1 after namelen so that the name string is terminated */
545 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
546 GFP_NOFS);
547 if (!kbuf) {
548 kfree(k32buf);
549 return -ENOMEM;
550 }
551
552 if (proc)
553 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
554
555 compat_input(kbuf, k32buf, namelen);
556 kfree(k32buf);
557 }
558 #endif
559
560 /* do we really need this? can a write happen after a close? */
561 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
562 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
563 error = -EINVAL;
564 goto out_free;
565 }
566
567 error = -EINVAL;
568
569 switch (kbuf->cmd)
570 {
571 case DLM_USER_LOCK:
572 if (!proc) {
573 log_print("no locking on control device");
574 goto out_free;
575 }
576 error = device_user_lock(proc, &kbuf->i.lock);
577 break;
578
579 case DLM_USER_UNLOCK:
580 if (!proc) {
581 log_print("no locking on control device");
582 goto out_free;
583 }
584 error = device_user_unlock(proc, &kbuf->i.lock);
585 break;
586
587 case DLM_USER_DEADLOCK:
588 if (!proc) {
589 log_print("no locking on control device");
590 goto out_free;
591 }
592 error = device_user_deadlock(proc, &kbuf->i.lock);
593 break;
594
595 case DLM_USER_CREATE_LOCKSPACE:
596 if (proc) {
597 log_print("create/remove only on control device");
598 goto out_free;
599 }
600 error = device_create_lockspace(&kbuf->i.lspace);
601 break;
602
603 case DLM_USER_REMOVE_LOCKSPACE:
604 if (proc) {
605 log_print("create/remove only on control device");
606 goto out_free;
607 }
608 error = device_remove_lockspace(&kbuf->i.lspace);
609 break;
610
611 case DLM_USER_PURGE:
612 if (!proc) {
613 log_print("no locking on control device");
614 goto out_free;
615 }
616 error = device_user_purge(proc, &kbuf->i.purge);
617 break;
618
619 default:
620 log_print("Unknown command passed to DLM device : %d\n",
621 kbuf->cmd);
622 }
623
624 out_free:
625 kfree(kbuf);
626 return error;
627 }
628
629 /* Every process that opens the lockspace device has its own "proc" structure
630 hanging off the open file that's used to keep track of locks owned by the
631 process and asts that need to be delivered to the process. */
632
device_open(struct inode * inode,struct file * file)633 static int device_open(struct inode *inode, struct file *file)
634 {
635 struct dlm_user_proc *proc;
636 struct dlm_ls *ls;
637
638 ls = dlm_find_lockspace_device(iminor(inode));
639 if (!ls)
640 return -ENOENT;
641
642 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
643 if (!proc) {
644 dlm_put_lockspace(ls);
645 return -ENOMEM;
646 }
647
648 proc->lockspace = ls->ls_local_handle;
649 INIT_LIST_HEAD(&proc->asts);
650 INIT_LIST_HEAD(&proc->locks);
651 INIT_LIST_HEAD(&proc->unlocking);
652 spin_lock_init(&proc->asts_spin);
653 spin_lock_init(&proc->locks_spin);
654 init_waitqueue_head(&proc->wait);
655 file->private_data = proc;
656
657 return 0;
658 }
659
device_close(struct inode * inode,struct file * file)660 static int device_close(struct inode *inode, struct file *file)
661 {
662 struct dlm_user_proc *proc = file->private_data;
663 struct dlm_ls *ls;
664
665 ls = dlm_find_lockspace_local(proc->lockspace);
666 if (!ls)
667 return -ENOENT;
668
669 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
670
671 dlm_clear_proc_locks(ls, proc);
672
673 /* at this point no more lkb's should exist for this lockspace,
674 so there's no chance of dlm_user_add_ast() being called and
675 looking for lkb->ua->proc */
676
677 kfree(proc);
678 file->private_data = NULL;
679
680 dlm_put_lockspace(ls);
681 dlm_put_lockspace(ls); /* for the find in device_open() */
682
683 /* FIXME: AUTOFREE: if this ls is no longer used do
684 device_remove_lockspace() */
685
686 return 0;
687 }
688
copy_result_to_user(struct dlm_user_args * ua,int compat,uint32_t flags,int mode,int copy_lvb,char __user * buf,size_t count)689 static int copy_result_to_user(struct dlm_user_args *ua, int compat,
690 uint32_t flags, int mode, int copy_lvb,
691 char __user *buf, size_t count)
692 {
693 #ifdef CONFIG_COMPAT
694 struct dlm_lock_result32 result32;
695 #endif
696 struct dlm_lock_result result;
697 void *resultptr;
698 int error=0;
699 int len;
700 int struct_len;
701
702 memset(&result, 0, sizeof(struct dlm_lock_result));
703 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
704 result.version[1] = DLM_DEVICE_VERSION_MINOR;
705 result.version[2] = DLM_DEVICE_VERSION_PATCH;
706 memcpy(&result.lksb, &ua->lksb, offsetof(struct dlm_lksb, sb_lvbptr));
707 result.user_lksb = ua->user_lksb;
708
709 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
710 in a conversion unless the conversion is successful. See code
711 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
712 notes that a new blocking AST address and parameter are set even if
713 the conversion fails, so maybe we should just do that. */
714
715 if (flags & DLM_CB_BAST) {
716 result.user_astaddr = ua->bastaddr;
717 result.user_astparam = ua->bastparam;
718 result.bast_mode = mode;
719 } else {
720 result.user_astaddr = ua->castaddr;
721 result.user_astparam = ua->castparam;
722 }
723
724 #ifdef CONFIG_COMPAT
725 if (compat)
726 len = sizeof(struct dlm_lock_result32);
727 else
728 #endif
729 len = sizeof(struct dlm_lock_result);
730 struct_len = len;
731
732 /* copy lvb to userspace if there is one, it's been updated, and
733 the user buffer has space for it */
734
735 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
736 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
737 DLM_USER_LVB_LEN)) {
738 error = -EFAULT;
739 goto out;
740 }
741
742 result.lvb_offset = len;
743 len += DLM_USER_LVB_LEN;
744 }
745
746 result.length = len;
747 resultptr = &result;
748 #ifdef CONFIG_COMPAT
749 if (compat) {
750 compat_output(&result, &result32);
751 resultptr = &result32;
752 }
753 #endif
754
755 if (copy_to_user(buf, resultptr, struct_len))
756 error = -EFAULT;
757 else
758 error = len;
759 out:
760 return error;
761 }
762
copy_version_to_user(char __user * buf,size_t count)763 static int copy_version_to_user(char __user *buf, size_t count)
764 {
765 struct dlm_device_version ver;
766
767 memset(&ver, 0, sizeof(struct dlm_device_version));
768 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
769 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
770 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
771
772 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
773 return -EFAULT;
774 return sizeof(struct dlm_device_version);
775 }
776
777 /* a read returns a single ast described in a struct dlm_lock_result */
778
device_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)779 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
780 loff_t *ppos)
781 {
782 struct dlm_user_proc *proc = file->private_data;
783 struct dlm_lkb *lkb;
784 DECLARE_WAITQUEUE(wait, current);
785 struct dlm_callback cb;
786 int rv, resid, copy_lvb = 0;
787 int old_mode, new_mode;
788
789 if (count == sizeof(struct dlm_device_version)) {
790 rv = copy_version_to_user(buf, count);
791 return rv;
792 }
793
794 if (!proc) {
795 log_print("non-version read from control device %zu", count);
796 return -EINVAL;
797 }
798
799 #ifdef CONFIG_COMPAT
800 if (count < sizeof(struct dlm_lock_result32))
801 #else
802 if (count < sizeof(struct dlm_lock_result))
803 #endif
804 return -EINVAL;
805
806 try_another:
807
808 /* do we really need this? can a read happen after a close? */
809 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
810 return -EINVAL;
811
812 spin_lock(&proc->asts_spin);
813 if (list_empty(&proc->asts)) {
814 if (file->f_flags & O_NONBLOCK) {
815 spin_unlock(&proc->asts_spin);
816 return -EAGAIN;
817 }
818
819 add_wait_queue(&proc->wait, &wait);
820
821 repeat:
822 set_current_state(TASK_INTERRUPTIBLE);
823 if (list_empty(&proc->asts) && !signal_pending(current)) {
824 spin_unlock(&proc->asts_spin);
825 schedule();
826 spin_lock(&proc->asts_spin);
827 goto repeat;
828 }
829 set_current_state(TASK_RUNNING);
830 remove_wait_queue(&proc->wait, &wait);
831
832 if (signal_pending(current)) {
833 spin_unlock(&proc->asts_spin);
834 return -ERESTARTSYS;
835 }
836 }
837
838 /* if we empty lkb_callbacks, we don't want to unlock the spinlock
839 without removing lkb_cb_list; so empty lkb_cb_list is always
840 consistent with empty lkb_callbacks */
841
842 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
843
844 /* rem_lkb_callback sets a new lkb_last_cast */
845 old_mode = lkb->lkb_last_cast.mode;
846
847 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
848 if (rv < 0) {
849 /* this shouldn't happen; lkb should have been removed from
850 list when resid was zero */
851 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
852 list_del_init(&lkb->lkb_cb_list);
853 spin_unlock(&proc->asts_spin);
854 /* removes ref for proc->asts, may cause lkb to be freed */
855 dlm_put_lkb(lkb);
856 goto try_another;
857 }
858 if (!resid)
859 list_del_init(&lkb->lkb_cb_list);
860 spin_unlock(&proc->asts_spin);
861
862 if (cb.flags & DLM_CB_SKIP) {
863 /* removes ref for proc->asts, may cause lkb to be freed */
864 if (!resid)
865 dlm_put_lkb(lkb);
866 goto try_another;
867 }
868
869 if (cb.flags & DLM_CB_CAST) {
870 new_mode = cb.mode;
871
872 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
873 dlm_lvb_operations[old_mode + 1][new_mode + 1])
874 copy_lvb = 1;
875
876 lkb->lkb_lksb->sb_status = cb.sb_status;
877 lkb->lkb_lksb->sb_flags = cb.sb_flags;
878 }
879
880 rv = copy_result_to_user(lkb->lkb_ua,
881 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
882 cb.flags, cb.mode, copy_lvb, buf, count);
883
884 /* removes ref for proc->asts, may cause lkb to be freed */
885 if (!resid)
886 dlm_put_lkb(lkb);
887
888 return rv;
889 }
890
device_poll(struct file * file,poll_table * wait)891 static __poll_t device_poll(struct file *file, poll_table *wait)
892 {
893 struct dlm_user_proc *proc = file->private_data;
894
895 poll_wait(file, &proc->wait, wait);
896
897 spin_lock(&proc->asts_spin);
898 if (!list_empty(&proc->asts)) {
899 spin_unlock(&proc->asts_spin);
900 return EPOLLIN | EPOLLRDNORM;
901 }
902 spin_unlock(&proc->asts_spin);
903 return 0;
904 }
905
dlm_user_daemon_available(void)906 int dlm_user_daemon_available(void)
907 {
908 /* dlm_controld hasn't started (or, has started, but not
909 properly populated configfs) */
910
911 if (!dlm_our_nodeid())
912 return 0;
913
914 /* This is to deal with versions of dlm_controld that don't
915 know about the monitor device. We assume that if the
916 dlm_controld was started (above), but the monitor device
917 was never opened, that it's an old version. dlm_controld
918 should open the monitor device before populating configfs. */
919
920 if (dlm_monitor_unused)
921 return 1;
922
923 return atomic_read(&dlm_monitor_opened) ? 1 : 0;
924 }
925
ctl_device_open(struct inode * inode,struct file * file)926 static int ctl_device_open(struct inode *inode, struct file *file)
927 {
928 file->private_data = NULL;
929 return 0;
930 }
931
ctl_device_close(struct inode * inode,struct file * file)932 static int ctl_device_close(struct inode *inode, struct file *file)
933 {
934 return 0;
935 }
936
monitor_device_open(struct inode * inode,struct file * file)937 static int monitor_device_open(struct inode *inode, struct file *file)
938 {
939 atomic_inc(&dlm_monitor_opened);
940 dlm_monitor_unused = 0;
941 return 0;
942 }
943
monitor_device_close(struct inode * inode,struct file * file)944 static int monitor_device_close(struct inode *inode, struct file *file)
945 {
946 if (atomic_dec_and_test(&dlm_monitor_opened))
947 dlm_stop_lockspaces();
948 return 0;
949 }
950
951 static const struct file_operations device_fops = {
952 .open = device_open,
953 .release = device_close,
954 .read = device_read,
955 .write = device_write,
956 .poll = device_poll,
957 .owner = THIS_MODULE,
958 .llseek = noop_llseek,
959 };
960
961 static const struct file_operations ctl_device_fops = {
962 .open = ctl_device_open,
963 .release = ctl_device_close,
964 .read = device_read,
965 .write = device_write,
966 .owner = THIS_MODULE,
967 .llseek = noop_llseek,
968 };
969
970 static struct miscdevice ctl_device = {
971 .name = "dlm-control",
972 .fops = &ctl_device_fops,
973 .minor = MISC_DYNAMIC_MINOR,
974 };
975
976 static const struct file_operations monitor_device_fops = {
977 .open = monitor_device_open,
978 .release = monitor_device_close,
979 .owner = THIS_MODULE,
980 .llseek = noop_llseek,
981 };
982
983 static struct miscdevice monitor_device = {
984 .name = "dlm-monitor",
985 .fops = &monitor_device_fops,
986 .minor = MISC_DYNAMIC_MINOR,
987 };
988
dlm_user_init(void)989 int __init dlm_user_init(void)
990 {
991 int error;
992
993 atomic_set(&dlm_monitor_opened, 0);
994
995 error = misc_register(&ctl_device);
996 if (error) {
997 log_print("misc_register failed for control device");
998 goto out;
999 }
1000
1001 error = misc_register(&monitor_device);
1002 if (error) {
1003 log_print("misc_register failed for monitor device");
1004 misc_deregister(&ctl_device);
1005 }
1006 out:
1007 return error;
1008 }
1009
dlm_user_exit(void)1010 void dlm_user_exit(void)
1011 {
1012 misc_deregister(&ctl_device);
1013 misc_deregister(&monitor_device);
1014 }
1015
1016