1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2006-2010 Red Hat, Inc. All rights reserved.
4 */
5
6 #include <linux/miscdevice.h>
7 #include <linux/init.h>
8 #include <linux/wait.h>
9 #include <linux/file.h>
10 #include <linux/fs.h>
11 #include <linux/poll.h>
12 #include <linux/signal.h>
13 #include <linux/spinlock.h>
14 #include <linux/dlm.h>
15 #include <linux/dlm_device.h>
16 #include <linux/slab.h>
17 #include <linux/sched/signal.h>
18
19 #include <trace/events/dlm.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 #include "ast.h"
27 #include "config.h"
28 #include "memory.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[];
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 = (__user void *)(long)kb32->i.lock.castparam;
115 kb->i.lock.castaddr = (__user void *)(long)kb32->i.lock.castaddr;
116 kb->i.lock.bastparam = (__user void *)(long)kb32->i.lock.bastparam;
117 kb->i.lock.bastaddr = (__user void *)(long)kb32->i.lock.bastaddr;
118 kb->i.lock.lksb = (__user 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)(__force long)res->user_astaddr;
134 res32->user_astparam = (__u32)(__force long)res->user_astparam;
135 res32->user_lksb = (__u32)(__force 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)178 void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode,
179 int status, uint32_t sbflags)
180 {
181 struct dlm_ls *ls;
182 struct dlm_user_args *ua;
183 struct dlm_user_proc *proc;
184 struct dlm_callback *cb;
185 int rv;
186
187 if (test_bit(DLM_DFL_ORPHAN_BIT, &lkb->lkb_dflags) ||
188 test_bit(DLM_IFL_DEAD_BIT, &lkb->lkb_iflags))
189 return;
190
191 ls = lkb->lkb_resource->res_ls;
192 spin_lock_bh(&ls->ls_clear_proc_locks);
193
194 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
195 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed
196 lkb->ua so we can't try to use it. This second check is necessary
197 for cases where a completion ast is received for an operation that
198 began before clear_proc_locks did its cancel/unlock. */
199
200 if (test_bit(DLM_DFL_ORPHAN_BIT, &lkb->lkb_dflags) ||
201 test_bit(DLM_IFL_DEAD_BIT, &lkb->lkb_iflags))
202 goto out;
203
204 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
205 ua = lkb->lkb_ua;
206 proc = ua->proc;
207
208 if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL)
209 goto out;
210
211 if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status))
212 set_bit(DLM_IFL_ENDOFLIFE_BIT, &lkb->lkb_iflags);
213
214 spin_lock_bh(&proc->asts_spin);
215
216 rv = dlm_queue_lkb_callback(lkb, flags, mode, status, sbflags, &cb);
217 switch (rv) {
218 case DLM_ENQUEUE_CALLBACK_NEED_SCHED:
219 cb->ua = *ua;
220 cb->lkb_lksb = &cb->ua.lksb;
221 if (cb->copy_lvb) {
222 memcpy(cb->lvbptr, ua->lksb.sb_lvbptr,
223 DLM_USER_LVB_LEN);
224 cb->lkb_lksb->sb_lvbptr = cb->lvbptr;
225 }
226
227 list_add_tail(&cb->list, &proc->asts);
228 wake_up_interruptible(&proc->wait);
229 break;
230 case DLM_ENQUEUE_CALLBACK_SUCCESS:
231 break;
232 case DLM_ENQUEUE_CALLBACK_FAILURE:
233 fallthrough;
234 default:
235 spin_unlock_bh(&proc->asts_spin);
236 WARN_ON_ONCE(1);
237 goto out;
238 }
239 spin_unlock_bh(&proc->asts_spin);
240
241 if (test_bit(DLM_IFL_ENDOFLIFE_BIT, &lkb->lkb_iflags)) {
242 /* N.B. spin_lock locks_spin, not asts_spin */
243 spin_lock_bh(&proc->locks_spin);
244 if (!list_empty(&lkb->lkb_ownqueue)) {
245 list_del_init(&lkb->lkb_ownqueue);
246 dlm_put_lkb(lkb);
247 }
248 spin_unlock_bh(&proc->locks_spin);
249 }
250 out:
251 spin_unlock_bh(&ls->ls_clear_proc_locks);
252 }
253
device_user_lock(struct dlm_user_proc * proc,struct dlm_lock_params * params)254 static int device_user_lock(struct dlm_user_proc *proc,
255 struct dlm_lock_params *params)
256 {
257 struct dlm_ls *ls;
258 struct dlm_user_args *ua;
259 uint32_t lkid;
260 int error = -ENOMEM;
261
262 ls = dlm_find_lockspace_local(proc->lockspace);
263 if (!ls)
264 return -ENOENT;
265
266 if (!params->castaddr || !params->lksb) {
267 error = -EINVAL;
268 goto out;
269 }
270
271 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
272 if (!ua)
273 goto out;
274 ua->proc = proc;
275 ua->user_lksb = params->lksb;
276 ua->castparam = params->castparam;
277 ua->castaddr = params->castaddr;
278 ua->bastparam = params->bastparam;
279 ua->bastaddr = params->bastaddr;
280 ua->xid = params->xid;
281
282 if (params->flags & DLM_LKF_CONVERT) {
283 error = dlm_user_convert(ls, ua,
284 params->mode, params->flags,
285 params->lkid, params->lvb);
286 } else if (params->flags & DLM_LKF_ORPHAN) {
287 error = dlm_user_adopt_orphan(ls, ua,
288 params->mode, params->flags,
289 params->name, params->namelen,
290 &lkid);
291 if (!error)
292 error = lkid;
293 } else {
294 error = dlm_user_request(ls, ua,
295 params->mode, params->flags,
296 params->name, params->namelen);
297 if (!error)
298 error = ua->lksb.sb_lkid;
299 }
300 out:
301 dlm_put_lockspace(ls);
302 return error;
303 }
304
device_user_unlock(struct dlm_user_proc * proc,struct dlm_lock_params * params)305 static int device_user_unlock(struct dlm_user_proc *proc,
306 struct dlm_lock_params *params)
307 {
308 struct dlm_ls *ls;
309 struct dlm_user_args *ua;
310 int error = -ENOMEM;
311
312 ls = dlm_find_lockspace_local(proc->lockspace);
313 if (!ls)
314 return -ENOENT;
315
316 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
317 if (!ua)
318 goto out;
319 ua->proc = proc;
320 ua->user_lksb = params->lksb;
321 ua->castparam = params->castparam;
322 ua->castaddr = params->castaddr;
323
324 if (params->flags & DLM_LKF_CANCEL)
325 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
326 else
327 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
328 params->lvb);
329 out:
330 dlm_put_lockspace(ls);
331 return error;
332 }
333
device_user_deadlock(struct dlm_user_proc * proc,struct dlm_lock_params * params)334 static int device_user_deadlock(struct dlm_user_proc *proc,
335 struct dlm_lock_params *params)
336 {
337 struct dlm_ls *ls;
338 int error;
339
340 ls = dlm_find_lockspace_local(proc->lockspace);
341 if (!ls)
342 return -ENOENT;
343
344 error = dlm_user_deadlock(ls, params->flags, params->lkid);
345
346 dlm_put_lockspace(ls);
347 return error;
348 }
349
dlm_device_register(struct dlm_ls * ls,char * name)350 static int dlm_device_register(struct dlm_ls *ls, char *name)
351 {
352 int error, len;
353
354 /* The device is already registered. This happens when the
355 lockspace is created multiple times from userspace. */
356 if (ls->ls_device.name)
357 return 0;
358
359 error = -ENOMEM;
360 len = strlen(name) + strlen(name_prefix) + 2;
361 ls->ls_device.name = kzalloc(len, GFP_NOFS);
362 if (!ls->ls_device.name)
363 goto fail;
364
365 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
366 name);
367 ls->ls_device.fops = &device_fops;
368 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
369
370 error = misc_register(&ls->ls_device);
371 if (error) {
372 kfree(ls->ls_device.name);
373 /* this has to be set to NULL
374 * to avoid a double-free in dlm_device_deregister
375 */
376 ls->ls_device.name = NULL;
377 }
378 fail:
379 return error;
380 }
381
dlm_device_deregister(struct dlm_ls * ls)382 int dlm_device_deregister(struct dlm_ls *ls)
383 {
384 /* The device is not registered. This happens when the lockspace
385 was never used from userspace, or when device_create_lockspace()
386 calls dlm_release_lockspace() after the register fails. */
387 if (!ls->ls_device.name)
388 return 0;
389
390 misc_deregister(&ls->ls_device);
391 kfree(ls->ls_device.name);
392 return 0;
393 }
394
device_user_purge(struct dlm_user_proc * proc,struct dlm_purge_params * params)395 static int device_user_purge(struct dlm_user_proc *proc,
396 struct dlm_purge_params *params)
397 {
398 struct dlm_ls *ls;
399 int error;
400
401 ls = dlm_find_lockspace_local(proc->lockspace);
402 if (!ls)
403 return -ENOENT;
404
405 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
406
407 dlm_put_lockspace(ls);
408 return error;
409 }
410
device_create_lockspace(struct dlm_lspace_params * params)411 static int device_create_lockspace(struct dlm_lspace_params *params)
412 {
413 dlm_lockspace_t *lockspace;
414 struct dlm_ls *ls;
415 int error;
416
417 if (!capable(CAP_SYS_ADMIN))
418 return -EPERM;
419
420 error = dlm_new_user_lockspace(params->name, dlm_config.ci_cluster_name,
421 params->flags, DLM_USER_LVB_LEN, NULL,
422 NULL, NULL, &lockspace);
423 if (error)
424 return error;
425
426 ls = dlm_find_lockspace_local(lockspace);
427 if (!ls)
428 return -ENOENT;
429
430 error = dlm_device_register(ls, params->name);
431 dlm_put_lockspace(ls);
432
433 if (error)
434 dlm_release_lockspace(lockspace, 0);
435 else
436 error = ls->ls_device.minor;
437
438 return error;
439 }
440
device_remove_lockspace(struct dlm_lspace_params * params)441 static int device_remove_lockspace(struct dlm_lspace_params *params)
442 {
443 dlm_lockspace_t *lockspace;
444 struct dlm_ls *ls;
445 int error, force = 0;
446
447 if (!capable(CAP_SYS_ADMIN))
448 return -EPERM;
449
450 ls = dlm_find_lockspace_device(params->minor);
451 if (!ls)
452 return -ENOENT;
453
454 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
455 force = 2;
456
457 lockspace = ls->ls_local_handle;
458 dlm_put_lockspace(ls);
459
460 /* The final dlm_release_lockspace waits for references to go to
461 zero, so all processes will need to close their device for the
462 ls before the release will proceed. release also calls the
463 device_deregister above. Converting a positive return value
464 from release to zero means that userspace won't know when its
465 release was the final one, but it shouldn't need to know. */
466
467 error = dlm_release_lockspace(lockspace, force);
468 if (error > 0)
469 error = 0;
470 return error;
471 }
472
473 /* Check the user's version matches ours */
check_version(struct dlm_write_request * req)474 static int check_version(struct dlm_write_request *req)
475 {
476 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
477 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
478 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
479
480 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
481 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
482 current->comm,
483 task_pid_nr(current),
484 req->version[0],
485 req->version[1],
486 req->version[2],
487 DLM_DEVICE_VERSION_MAJOR,
488 DLM_DEVICE_VERSION_MINOR,
489 DLM_DEVICE_VERSION_PATCH);
490 return -EINVAL;
491 }
492 return 0;
493 }
494
495 /*
496 * device_write
497 *
498 * device_user_lock
499 * dlm_user_request -> request_lock
500 * dlm_user_convert -> convert_lock
501 *
502 * device_user_unlock
503 * dlm_user_unlock -> unlock_lock
504 * dlm_user_cancel -> cancel_lock
505 *
506 * device_create_lockspace
507 * dlm_new_lockspace
508 *
509 * device_remove_lockspace
510 * dlm_release_lockspace
511 */
512
513 /* a write to a lockspace device is a lock or unlock request, a write
514 to the control device is to create/remove a lockspace */
515
device_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)516 static ssize_t device_write(struct file *file, const char __user *buf,
517 size_t count, loff_t *ppos)
518 {
519 struct dlm_user_proc *proc = file->private_data;
520 struct dlm_write_request *kbuf;
521 int error;
522
523 #ifdef CONFIG_COMPAT
524 if (count < sizeof(struct dlm_write_request32))
525 #else
526 if (count < sizeof(struct dlm_write_request))
527 #endif
528 return -EINVAL;
529
530 /*
531 * can't compare against COMPAT/dlm_write_request32 because
532 * we don't yet know if is64bit is zero
533 */
534 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
535 return -EINVAL;
536
537 kbuf = memdup_user_nul(buf, count);
538 if (IS_ERR(kbuf))
539 return PTR_ERR(kbuf);
540
541 if (check_version(kbuf)) {
542 error = -EBADE;
543 goto out_free;
544 }
545
546 #ifdef CONFIG_COMPAT
547 if (!kbuf->is64bit) {
548 struct dlm_write_request32 *k32buf;
549 int namelen = 0;
550
551 if (count > sizeof(struct dlm_write_request32))
552 namelen = count - sizeof(struct dlm_write_request32);
553
554 k32buf = (struct dlm_write_request32 *)kbuf;
555
556 /* add 1 after namelen so that the name string is terminated */
557 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
558 GFP_NOFS);
559 if (!kbuf) {
560 kfree(k32buf);
561 return -ENOMEM;
562 }
563
564 if (proc)
565 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
566
567 compat_input(kbuf, k32buf, namelen);
568 kfree(k32buf);
569 }
570 #endif
571
572 /* do we really need this? can a write happen after a close? */
573 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
574 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
575 error = -EINVAL;
576 goto out_free;
577 }
578
579 error = -EINVAL;
580
581 switch (kbuf->cmd)
582 {
583 case DLM_USER_LOCK:
584 if (!proc) {
585 log_print("no locking on control device");
586 goto out_free;
587 }
588 error = device_user_lock(proc, &kbuf->i.lock);
589 break;
590
591 case DLM_USER_UNLOCK:
592 if (!proc) {
593 log_print("no locking on control device");
594 goto out_free;
595 }
596 error = device_user_unlock(proc, &kbuf->i.lock);
597 break;
598
599 case DLM_USER_DEADLOCK:
600 if (!proc) {
601 log_print("no locking on control device");
602 goto out_free;
603 }
604 error = device_user_deadlock(proc, &kbuf->i.lock);
605 break;
606
607 case DLM_USER_CREATE_LOCKSPACE:
608 if (proc) {
609 log_print("create/remove only on control device");
610 goto out_free;
611 }
612 error = device_create_lockspace(&kbuf->i.lspace);
613 break;
614
615 case DLM_USER_REMOVE_LOCKSPACE:
616 if (proc) {
617 log_print("create/remove only on control device");
618 goto out_free;
619 }
620 error = device_remove_lockspace(&kbuf->i.lspace);
621 break;
622
623 case DLM_USER_PURGE:
624 if (!proc) {
625 log_print("no locking on control device");
626 goto out_free;
627 }
628 error = device_user_purge(proc, &kbuf->i.purge);
629 break;
630
631 default:
632 log_print("Unknown command passed to DLM device : %d\n",
633 kbuf->cmd);
634 }
635
636 out_free:
637 kfree(kbuf);
638 return error;
639 }
640
641 /* Every process that opens the lockspace device has its own "proc" structure
642 hanging off the open file that's used to keep track of locks owned by the
643 process and asts that need to be delivered to the process. */
644
device_open(struct inode * inode,struct file * file)645 static int device_open(struct inode *inode, struct file *file)
646 {
647 struct dlm_user_proc *proc;
648 struct dlm_ls *ls;
649
650 ls = dlm_find_lockspace_device(iminor(inode));
651 if (!ls)
652 return -ENOENT;
653
654 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
655 if (!proc) {
656 dlm_put_lockspace(ls);
657 return -ENOMEM;
658 }
659
660 proc->lockspace = ls->ls_local_handle;
661 INIT_LIST_HEAD(&proc->asts);
662 INIT_LIST_HEAD(&proc->locks);
663 INIT_LIST_HEAD(&proc->unlocking);
664 spin_lock_init(&proc->asts_spin);
665 spin_lock_init(&proc->locks_spin);
666 init_waitqueue_head(&proc->wait);
667 file->private_data = proc;
668
669 return 0;
670 }
671
device_close(struct inode * inode,struct file * file)672 static int device_close(struct inode *inode, struct file *file)
673 {
674 struct dlm_user_proc *proc = file->private_data;
675 struct dlm_ls *ls;
676
677 ls = dlm_find_lockspace_local(proc->lockspace);
678 if (!ls)
679 return -ENOENT;
680
681 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
682
683 dlm_clear_proc_locks(ls, proc);
684
685 /* at this point no more lkb's should exist for this lockspace,
686 so there's no chance of dlm_user_add_ast() being called and
687 looking for lkb->ua->proc */
688
689 kfree(proc);
690 file->private_data = NULL;
691
692 dlm_put_lockspace(ls);
693 dlm_put_lockspace(ls); /* for the find in device_open() */
694
695 /* FIXME: AUTOFREE: if this ls is no longer used do
696 device_remove_lockspace() */
697
698 return 0;
699 }
700
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)701 static int copy_result_to_user(struct dlm_user_args *ua, int compat,
702 uint32_t flags, int mode, int copy_lvb,
703 char __user *buf, size_t count)
704 {
705 #ifdef CONFIG_COMPAT
706 struct dlm_lock_result32 result32;
707 #endif
708 struct dlm_lock_result result;
709 void *resultptr;
710 int error=0;
711 int len;
712 int struct_len;
713
714 memset(&result, 0, sizeof(struct dlm_lock_result));
715 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
716 result.version[1] = DLM_DEVICE_VERSION_MINOR;
717 result.version[2] = DLM_DEVICE_VERSION_PATCH;
718 memcpy(&result.lksb, &ua->lksb, offsetof(struct dlm_lksb, sb_lvbptr));
719 result.user_lksb = ua->user_lksb;
720
721 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
722 in a conversion unless the conversion is successful. See code
723 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
724 notes that a new blocking AST address and parameter are set even if
725 the conversion fails, so maybe we should just do that. */
726
727 if (flags & DLM_CB_BAST) {
728 result.user_astaddr = ua->bastaddr;
729 result.user_astparam = ua->bastparam;
730 result.bast_mode = mode;
731 } else {
732 result.user_astaddr = ua->castaddr;
733 result.user_astparam = ua->castparam;
734 }
735
736 #ifdef CONFIG_COMPAT
737 if (compat)
738 len = sizeof(struct dlm_lock_result32);
739 else
740 #endif
741 len = sizeof(struct dlm_lock_result);
742 struct_len = len;
743
744 /* copy lvb to userspace if there is one, it's been updated, and
745 the user buffer has space for it */
746
747 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
748 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
749 DLM_USER_LVB_LEN)) {
750 error = -EFAULT;
751 goto out;
752 }
753
754 result.lvb_offset = len;
755 len += DLM_USER_LVB_LEN;
756 }
757
758 result.length = len;
759 resultptr = &result;
760 #ifdef CONFIG_COMPAT
761 if (compat) {
762 compat_output(&result, &result32);
763 resultptr = &result32;
764 }
765 #endif
766
767 if (copy_to_user(buf, resultptr, struct_len))
768 error = -EFAULT;
769 else
770 error = len;
771 out:
772 return error;
773 }
774
copy_version_to_user(char __user * buf,size_t count)775 static int copy_version_to_user(char __user *buf, size_t count)
776 {
777 struct dlm_device_version ver;
778
779 memset(&ver, 0, sizeof(struct dlm_device_version));
780 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
781 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
782 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
783
784 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
785 return -EFAULT;
786 return sizeof(struct dlm_device_version);
787 }
788
789 /* a read returns a single ast described in a struct dlm_lock_result */
790
device_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)791 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
792 loff_t *ppos)
793 {
794 struct dlm_user_proc *proc = file->private_data;
795 DECLARE_WAITQUEUE(wait, current);
796 struct dlm_callback *cb;
797 int rv, ret;
798
799 if (count == sizeof(struct dlm_device_version)) {
800 rv = copy_version_to_user(buf, count);
801 return rv;
802 }
803
804 if (!proc) {
805 log_print("non-version read from control device %zu", count);
806 return -EINVAL;
807 }
808
809 #ifdef CONFIG_COMPAT
810 if (count < sizeof(struct dlm_lock_result32))
811 #else
812 if (count < sizeof(struct dlm_lock_result))
813 #endif
814 return -EINVAL;
815
816 /* do we really need this? can a read happen after a close? */
817 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
818 return -EINVAL;
819
820 spin_lock_bh(&proc->asts_spin);
821 if (list_empty(&proc->asts)) {
822 if (file->f_flags & O_NONBLOCK) {
823 spin_unlock_bh(&proc->asts_spin);
824 return -EAGAIN;
825 }
826
827 add_wait_queue(&proc->wait, &wait);
828
829 repeat:
830 set_current_state(TASK_INTERRUPTIBLE);
831 if (list_empty(&proc->asts) && !signal_pending(current)) {
832 spin_unlock_bh(&proc->asts_spin);
833 schedule();
834 spin_lock_bh(&proc->asts_spin);
835 goto repeat;
836 }
837 set_current_state(TASK_RUNNING);
838 remove_wait_queue(&proc->wait, &wait);
839
840 if (signal_pending(current)) {
841 spin_unlock_bh(&proc->asts_spin);
842 return -ERESTARTSYS;
843 }
844 }
845
846 /* if we empty lkb_callbacks, we don't want to unlock the spinlock
847 without removing lkb_cb_list; so empty lkb_cb_list is always
848 consistent with empty lkb_callbacks */
849
850 cb = list_first_entry(&proc->asts, struct dlm_callback, list);
851 list_del(&cb->list);
852 spin_unlock_bh(&proc->asts_spin);
853
854 if (cb->flags & DLM_CB_BAST) {
855 trace_dlm_bast(cb->ls_id, cb->lkb_id, cb->mode, cb->res_name,
856 cb->res_length);
857 } else if (cb->flags & DLM_CB_CAST) {
858 cb->lkb_lksb->sb_status = cb->sb_status;
859 cb->lkb_lksb->sb_flags = cb->sb_flags;
860 trace_dlm_ast(cb->ls_id, cb->lkb_id, cb->sb_status,
861 cb->sb_flags, cb->res_name, cb->res_length);
862 }
863
864 ret = copy_result_to_user(&cb->ua,
865 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
866 cb->flags, cb->mode, cb->copy_lvb, buf, count);
867 dlm_free_cb(cb);
868 return ret;
869 }
870
device_poll(struct file * file,poll_table * wait)871 static __poll_t device_poll(struct file *file, poll_table *wait)
872 {
873 struct dlm_user_proc *proc = file->private_data;
874
875 poll_wait(file, &proc->wait, wait);
876
877 spin_lock_bh(&proc->asts_spin);
878 if (!list_empty(&proc->asts)) {
879 spin_unlock_bh(&proc->asts_spin);
880 return EPOLLIN | EPOLLRDNORM;
881 }
882 spin_unlock_bh(&proc->asts_spin);
883 return 0;
884 }
885
dlm_user_daemon_available(void)886 int dlm_user_daemon_available(void)
887 {
888 /* dlm_controld hasn't started (or, has started, but not
889 properly populated configfs) */
890
891 if (!dlm_our_nodeid())
892 return 0;
893
894 /* This is to deal with versions of dlm_controld that don't
895 know about the monitor device. We assume that if the
896 dlm_controld was started (above), but the monitor device
897 was never opened, that it's an old version. dlm_controld
898 should open the monitor device before populating configfs. */
899
900 if (dlm_monitor_unused)
901 return 1;
902
903 return atomic_read(&dlm_monitor_opened) ? 1 : 0;
904 }
905
ctl_device_open(struct inode * inode,struct file * file)906 static int ctl_device_open(struct inode *inode, struct file *file)
907 {
908 file->private_data = NULL;
909 return 0;
910 }
911
ctl_device_close(struct inode * inode,struct file * file)912 static int ctl_device_close(struct inode *inode, struct file *file)
913 {
914 return 0;
915 }
916
monitor_device_open(struct inode * inode,struct file * file)917 static int monitor_device_open(struct inode *inode, struct file *file)
918 {
919 atomic_inc(&dlm_monitor_opened);
920 dlm_monitor_unused = 0;
921 return 0;
922 }
923
monitor_device_close(struct inode * inode,struct file * file)924 static int monitor_device_close(struct inode *inode, struct file *file)
925 {
926 if (atomic_dec_and_test(&dlm_monitor_opened))
927 dlm_stop_lockspaces();
928 return 0;
929 }
930
931 static const struct file_operations device_fops = {
932 .open = device_open,
933 .release = device_close,
934 .read = device_read,
935 .write = device_write,
936 .poll = device_poll,
937 .owner = THIS_MODULE,
938 .llseek = noop_llseek,
939 };
940
941 static const struct file_operations ctl_device_fops = {
942 .open = ctl_device_open,
943 .release = ctl_device_close,
944 .read = device_read,
945 .write = device_write,
946 .owner = THIS_MODULE,
947 .llseek = noop_llseek,
948 };
949
950 static struct miscdevice ctl_device = {
951 .name = "dlm-control",
952 .fops = &ctl_device_fops,
953 .minor = MISC_DYNAMIC_MINOR,
954 };
955
956 static const struct file_operations monitor_device_fops = {
957 .open = monitor_device_open,
958 .release = monitor_device_close,
959 .owner = THIS_MODULE,
960 .llseek = noop_llseek,
961 };
962
963 static struct miscdevice monitor_device = {
964 .name = "dlm-monitor",
965 .fops = &monitor_device_fops,
966 .minor = MISC_DYNAMIC_MINOR,
967 };
968
dlm_user_init(void)969 int __init dlm_user_init(void)
970 {
971 int error;
972
973 atomic_set(&dlm_monitor_opened, 0);
974
975 error = misc_register(&ctl_device);
976 if (error) {
977 log_print("misc_register failed for control device");
978 goto out;
979 }
980
981 error = misc_register(&monitor_device);
982 if (error) {
983 log_print("misc_register failed for monitor device");
984 misc_deregister(&ctl_device);
985 }
986 out:
987 return error;
988 }
989
dlm_user_exit(void)990 void dlm_user_exit(void)
991 {
992 misc_deregister(&ctl_device);
993 misc_deregister(&monitor_device);
994 }
995
996