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TOMOYO Linux Cross Reference
Linux/fs/dlm/user.c

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  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 "dlm_internal.h"
 20 #include "lockspace.h"
 21 #include "lock.h"
 22 #include "lvb_table.h"
 23 #include "user.h"
 24 #include "ast.h"
 25 #include "config.h"
 26 
 27 static const char name_prefix[] = "dlm";
 28 static const struct file_operations device_fops;
 29 static atomic_t dlm_monitor_opened;
 30 static int dlm_monitor_unused = 1;
 31 
 32 #ifdef CONFIG_COMPAT
 33 
 34 struct dlm_lock_params32 {
 35         __u8 mode;
 36         __u8 namelen;
 37         __u16 unused;
 38         __u32 flags;
 39         __u32 lkid;
 40         __u32 parent;
 41         __u64 xid;
 42         __u64 timeout;
 43         __u32 castparam;
 44         __u32 castaddr;
 45         __u32 bastparam;
 46         __u32 bastaddr;
 47         __u32 lksb;
 48         char lvb[DLM_USER_LVB_LEN];
 49         char name[0];
 50 };
 51 
 52 struct dlm_write_request32 {
 53         __u32 version[3];
 54         __u8 cmd;
 55         __u8 is64bit;
 56         __u8 unused[2];
 57 
 58         union  {
 59                 struct dlm_lock_params32 lock;
 60                 struct dlm_lspace_params lspace;
 61                 struct dlm_purge_params purge;
 62         } i;
 63 };
 64 
 65 struct dlm_lksb32 {
 66         __u32 sb_status;
 67         __u32 sb_lkid;
 68         __u8 sb_flags;
 69         __u32 sb_lvbptr;
 70 };
 71 
 72 struct dlm_lock_result32 {
 73         __u32 version[3];
 74         __u32 length;
 75         __u32 user_astaddr;
 76         __u32 user_astparam;
 77         __u32 user_lksb;
 78         struct dlm_lksb32 lksb;
 79         __u8 bast_mode;
 80         __u8 unused[3];
 81         /* Offsets may be zero if no data is present */
 82         __u32 lvb_offset;
 83 };
 84 
 85 static void compat_input(struct dlm_write_request *kb,
 86                          struct dlm_write_request32 *kb32,
 87                          int namelen)
 88 {
 89         kb->version[0] = kb32->version[0];
 90         kb->version[1] = kb32->version[1];
 91         kb->version[2] = kb32->version[2];
 92 
 93         kb->cmd = kb32->cmd;
 94         kb->is64bit = kb32->is64bit;
 95         if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
 96             kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
 97                 kb->i.lspace.flags = kb32->i.lspace.flags;
 98                 kb->i.lspace.minor = kb32->i.lspace.minor;
 99                 memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
100         } else if (kb->cmd == DLM_USER_PURGE) {
101                 kb->i.purge.nodeid = kb32->i.purge.nodeid;
102                 kb->i.purge.pid = kb32->i.purge.pid;
103         } else {
104                 kb->i.lock.mode = kb32->i.lock.mode;
105                 kb->i.lock.namelen = kb32->i.lock.namelen;
106                 kb->i.lock.flags = kb32->i.lock.flags;
107                 kb->i.lock.lkid = kb32->i.lock.lkid;
108                 kb->i.lock.parent = kb32->i.lock.parent;
109                 kb->i.lock.xid = kb32->i.lock.xid;
110                 kb->i.lock.timeout = kb32->i.lock.timeout;
111                 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
112                 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
113                 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
114                 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
115                 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
116                 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
117                 memcpy(kb->i.lock.name, kb32->i.lock.name, namelen);
118         }
119 }
120 
121 static void compat_output(struct dlm_lock_result *res,
122                           struct dlm_lock_result32 *res32)
123 {
124         memset(res32, 0, sizeof(*res32));
125 
126         res32->version[0] = res->version[0];
127         res32->version[1] = res->version[1];
128         res32->version[2] = res->version[2];
129 
130         res32->user_astaddr = (__u32)(long)res->user_astaddr;
131         res32->user_astparam = (__u32)(long)res->user_astparam;
132         res32->user_lksb = (__u32)(long)res->user_lksb;
133         res32->bast_mode = res->bast_mode;
134 
135         res32->lvb_offset = res->lvb_offset;
136         res32->length = res->length;
137 
138         res32->lksb.sb_status = res->lksb.sb_status;
139         res32->lksb.sb_flags = res->lksb.sb_flags;
140         res32->lksb.sb_lkid = res->lksb.sb_lkid;
141         res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
142 }
143 #endif
144 
145 /* Figure out if this lock is at the end of its life and no longer
146    available for the application to use.  The lkb still exists until
147    the final ast is read.  A lock becomes EOL in three situations:
148      1. a noqueue request fails with EAGAIN
149      2. an unlock completes with EUNLOCK
150      3. a cancel of a waiting request completes with ECANCEL/EDEADLK
151    An EOL lock needs to be removed from the process's list of locks.
152    And we can't allow any new operation on an EOL lock.  This is
153    not related to the lifetime of the lkb struct which is managed
154    entirely by refcount. */
155 
156 static int lkb_is_endoflife(int mode, int status)
157 {
158         switch (status) {
159         case -DLM_EUNLOCK:
160                 return 1;
161         case -DLM_ECANCEL:
162         case -ETIMEDOUT:
163         case -EDEADLK:
164         case -EAGAIN:
165                 if (mode == DLM_LOCK_IV)
166                         return 1;
167                 break;
168         }
169         return 0;
170 }
171 
172 /* we could possibly check if the cancel of an orphan has resulted in the lkb
173    being removed and then remove that lkb from the orphans list and free it */
174 
175 void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode,
176                       int status, uint32_t sbflags, uint64_t seq)
177 {
178         struct dlm_ls *ls;
179         struct dlm_user_args *ua;
180         struct dlm_user_proc *proc;
181         int rv;
182 
183         if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
184                 return;
185 
186         ls = lkb->lkb_resource->res_ls;
187         mutex_lock(&ls->ls_clear_proc_locks);
188 
189         /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
190            can't be delivered.  For ORPHAN's, dlm_clear_proc_locks() freed
191            lkb->ua so we can't try to use it.  This second check is necessary
192            for cases where a completion ast is received for an operation that
193            began before clear_proc_locks did its cancel/unlock. */
194 
195         if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
196                 goto out;
197 
198         DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
199         ua = lkb->lkb_ua;
200         proc = ua->proc;
201 
202         if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL)
203                 goto out;
204 
205         if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status))
206                 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
207 
208         spin_lock(&proc->asts_spin);
209 
210         rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq);
211         if (rv < 0) {
212                 spin_unlock(&proc->asts_spin);
213                 goto out;
214         }
215 
216         if (list_empty(&lkb->lkb_cb_list)) {
217                 kref_get(&lkb->lkb_ref);
218                 list_add_tail(&lkb->lkb_cb_list, &proc->asts);
219                 wake_up_interruptible(&proc->wait);
220         }
221         spin_unlock(&proc->asts_spin);
222 
223         if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) {
224                 /* N.B. spin_lock locks_spin, not asts_spin */
225                 spin_lock(&proc->locks_spin);
226                 if (!list_empty(&lkb->lkb_ownqueue)) {
227                         list_del_init(&lkb->lkb_ownqueue);
228                         dlm_put_lkb(lkb);
229                 }
230                 spin_unlock(&proc->locks_spin);
231         }
232  out:
233         mutex_unlock(&ls->ls_clear_proc_locks);
234 }
235 
236 static int device_user_lock(struct dlm_user_proc *proc,
237                             struct dlm_lock_params *params)
238 {
239         struct dlm_ls *ls;
240         struct dlm_user_args *ua;
241         uint32_t lkid;
242         int error = -ENOMEM;
243 
244         ls = dlm_find_lockspace_local(proc->lockspace);
245         if (!ls)
246                 return -ENOENT;
247 
248         if (!params->castaddr || !params->lksb) {
249                 error = -EINVAL;
250                 goto out;
251         }
252 
253         ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
254         if (!ua)
255                 goto out;
256         ua->proc = proc;
257         ua->user_lksb = params->lksb;
258         ua->castparam = params->castparam;
259         ua->castaddr = params->castaddr;
260         ua->bastparam = params->bastparam;
261         ua->bastaddr = params->bastaddr;
262         ua->xid = params->xid;
263 
264         if (params->flags & DLM_LKF_CONVERT) {
265                 error = dlm_user_convert(ls, ua,
266                                          params->mode, params->flags,
267                                          params->lkid, params->lvb,
268                                          (unsigned long) params->timeout);
269         } else if (params->flags & DLM_LKF_ORPHAN) {
270                 error = dlm_user_adopt_orphan(ls, ua,
271                                          params->mode, params->flags,
272                                          params->name, params->namelen,
273                                          (unsigned long) params->timeout,
274                                          &lkid);
275                 if (!error)
276                         error = lkid;
277         } else {
278                 error = dlm_user_request(ls, ua,
279                                          params->mode, params->flags,
280                                          params->name, params->namelen,
281                                          (unsigned long) params->timeout);
282                 if (!error)
283                         error = ua->lksb.sb_lkid;
284         }
285  out:
286         dlm_put_lockspace(ls);
287         return error;
288 }
289 
290 static int device_user_unlock(struct dlm_user_proc *proc,
291                               struct dlm_lock_params *params)
292 {
293         struct dlm_ls *ls;
294         struct dlm_user_args *ua;
295         int error = -ENOMEM;
296 
297         ls = dlm_find_lockspace_local(proc->lockspace);
298         if (!ls)
299                 return -ENOENT;
300 
301         ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
302         if (!ua)
303                 goto out;
304         ua->proc = proc;
305         ua->user_lksb = params->lksb;
306         ua->castparam = params->castparam;
307         ua->castaddr = params->castaddr;
308 
309         if (params->flags & DLM_LKF_CANCEL)
310                 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
311         else
312                 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
313                                         params->lvb);
314  out:
315         dlm_put_lockspace(ls);
316         return error;
317 }
318 
319 static int device_user_deadlock(struct dlm_user_proc *proc,
320                                 struct dlm_lock_params *params)
321 {
322         struct dlm_ls *ls;
323         int error;
324 
325         ls = dlm_find_lockspace_local(proc->lockspace);
326         if (!ls)
327                 return -ENOENT;
328 
329         error = dlm_user_deadlock(ls, params->flags, params->lkid);
330 
331         dlm_put_lockspace(ls);
332         return error;
333 }
334 
335 static int dlm_device_register(struct dlm_ls *ls, char *name)
336 {
337         int error, len;
338 
339         /* The device is already registered.  This happens when the
340            lockspace is created multiple times from userspace. */
341         if (ls->ls_device.name)
342                 return 0;
343 
344         error = -ENOMEM;
345         len = strlen(name) + strlen(name_prefix) + 2;
346         ls->ls_device.name = kzalloc(len, GFP_NOFS);
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                 /* this has to be set to NULL
359                  * to avoid a double-free in dlm_device_deregister
360                  */
361                 ls->ls_device.name = NULL;
362         }
363 fail:
364         return error;
365 }
366 
367 int dlm_device_deregister(struct dlm_ls *ls)
368 {
369         /* The device is not registered.  This happens when the lockspace
370            was never used from userspace, or when device_create_lockspace()
371            calls dlm_release_lockspace() after the register fails. */
372         if (!ls->ls_device.name)
373                 return 0;
374 
375         misc_deregister(&ls->ls_device);
376         kfree(ls->ls_device.name);
377         return 0;
378 }
379 
380 static int device_user_purge(struct dlm_user_proc *proc,
381                              struct dlm_purge_params *params)
382 {
383         struct dlm_ls *ls;
384         int error;
385 
386         ls = dlm_find_lockspace_local(proc->lockspace);
387         if (!ls)
388                 return -ENOENT;
389 
390         error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
391 
392         dlm_put_lockspace(ls);
393         return error;
394 }
395 
396 static int device_create_lockspace(struct dlm_lspace_params *params)
397 {
398         dlm_lockspace_t *lockspace;
399         struct dlm_ls *ls;
400         int error;
401 
402         if (!capable(CAP_SYS_ADMIN))
403                 return -EPERM;
404 
405         error = dlm_new_lockspace(params->name, dlm_config.ci_cluster_name, params->flags,
406                                   DLM_USER_LVB_LEN, NULL, NULL, NULL,
407                                   &lockspace);
408         if (error)
409                 return error;
410 
411         ls = dlm_find_lockspace_local(lockspace);
412         if (!ls)
413                 return -ENOENT;
414 
415         error = dlm_device_register(ls, params->name);
416         dlm_put_lockspace(ls);
417 
418         if (error)
419                 dlm_release_lockspace(lockspace, 0);
420         else
421                 error = ls->ls_device.minor;
422 
423         return error;
424 }
425 
426 static int device_remove_lockspace(struct dlm_lspace_params *params)
427 {
428         dlm_lockspace_t *lockspace;
429         struct dlm_ls *ls;
430         int error, force = 0;
431 
432         if (!capable(CAP_SYS_ADMIN))
433                 return -EPERM;
434 
435         ls = dlm_find_lockspace_device(params->minor);
436         if (!ls)
437                 return -ENOENT;
438 
439         if (params->flags & DLM_USER_LSFLG_FORCEFREE)
440                 force = 2;
441 
442         lockspace = ls->ls_local_handle;
443         dlm_put_lockspace(ls);
444 
445         /* The final dlm_release_lockspace waits for references to go to
446            zero, so all processes will need to close their device for the
447            ls before the release will proceed.  release also calls the
448            device_deregister above.  Converting a positive return value
449            from release to zero means that userspace won't know when its
450            release was the final one, but it shouldn't need to know. */
451 
452         error = dlm_release_lockspace(lockspace, force);
453         if (error > 0)
454                 error = 0;
455         return error;
456 }
457 
458 /* Check the user's version matches ours */
459 static int check_version(struct dlm_write_request *req)
460 {
461         if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
462             (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
463              req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
464 
465                 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
466                        "user (%d.%d.%d) kernel (%d.%d.%d)\n",
467                        current->comm,
468                        task_pid_nr(current),
469                        req->version[0],
470                        req->version[1],
471                        req->version[2],
472                        DLM_DEVICE_VERSION_MAJOR,
473                        DLM_DEVICE_VERSION_MINOR,
474                        DLM_DEVICE_VERSION_PATCH);
475                 return -EINVAL;
476         }
477         return 0;
478 }
479 
480 /*
481  * device_write
482  *
483  *   device_user_lock
484  *     dlm_user_request -> request_lock
485  *     dlm_user_convert -> convert_lock
486  *
487  *   device_user_unlock
488  *     dlm_user_unlock -> unlock_lock
489  *     dlm_user_cancel -> cancel_lock
490  *
491  *   device_create_lockspace
492  *     dlm_new_lockspace
493  *
494  *   device_remove_lockspace
495  *     dlm_release_lockspace
496  */
497 
498 /* a write to a lockspace device is a lock or unlock request, a write
499    to the control device is to create/remove a lockspace */
500 
501 static ssize_t device_write(struct file *file, const char __user *buf,
502                             size_t count, loff_t *ppos)
503 {
504         struct dlm_user_proc *proc = file->private_data;
505         struct dlm_write_request *kbuf;
506         int error;
507 
508 #ifdef CONFIG_COMPAT
509         if (count < sizeof(struct dlm_write_request32))
510 #else
511         if (count < sizeof(struct dlm_write_request))
512 #endif
513                 return -EINVAL;
514 
515         /*
516          * can't compare against COMPAT/dlm_write_request32 because
517          * we don't yet know if is64bit is zero
518          */
519         if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
520                 return -EINVAL;
521 
522         kbuf = memdup_user_nul(buf, count);
523         if (IS_ERR(kbuf))
524                 return PTR_ERR(kbuf);
525 
526         if (check_version(kbuf)) {
527                 error = -EBADE;
528                 goto out_free;
529         }
530 
531 #ifdef CONFIG_COMPAT
532         if (!kbuf->is64bit) {
533                 struct dlm_write_request32 *k32buf;
534                 int namelen = 0;
535 
536                 if (count > sizeof(struct dlm_write_request32))
537                         namelen = count - sizeof(struct dlm_write_request32);
538 
539                 k32buf = (struct dlm_write_request32 *)kbuf;
540 
541                 /* add 1 after namelen so that the name string is terminated */
542                 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
543                                GFP_NOFS);
544                 if (!kbuf) {
545                         kfree(k32buf);
546                         return -ENOMEM;
547                 }
548 
549                 if (proc)
550                         set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
551 
552                 compat_input(kbuf, k32buf, namelen);
553                 kfree(k32buf);
554         }
555 #endif
556 
557         /* do we really need this? can a write happen after a close? */
558         if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
559             (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
560                 error = -EINVAL;
561                 goto out_free;
562         }
563 
564         error = -EINVAL;
565 
566         switch (kbuf->cmd)
567         {
568         case DLM_USER_LOCK:
569                 if (!proc) {
570                         log_print("no locking on control device");
571                         goto out_free;
572                 }
573                 error = device_user_lock(proc, &kbuf->i.lock);
574                 break;
575 
576         case DLM_USER_UNLOCK:
577                 if (!proc) {
578                         log_print("no locking on control device");
579                         goto out_free;
580                 }
581                 error = device_user_unlock(proc, &kbuf->i.lock);
582                 break;
583 
584         case DLM_USER_DEADLOCK:
585                 if (!proc) {
586                         log_print("no locking on control device");
587                         goto out_free;
588                 }
589                 error = device_user_deadlock(proc, &kbuf->i.lock);
590                 break;
591 
592         case DLM_USER_CREATE_LOCKSPACE:
593                 if (proc) {
594                         log_print("create/remove only on control device");
595                         goto out_free;
596                 }
597                 error = device_create_lockspace(&kbuf->i.lspace);
598                 break;
599 
600         case DLM_USER_REMOVE_LOCKSPACE:
601                 if (proc) {
602                         log_print("create/remove only on control device");
603                         goto out_free;
604                 }
605                 error = device_remove_lockspace(&kbuf->i.lspace);
606                 break;
607 
608         case DLM_USER_PURGE:
609                 if (!proc) {
610                         log_print("no locking on control device");
611                         goto out_free;
612                 }
613                 error = device_user_purge(proc, &kbuf->i.purge);
614                 break;
615 
616         default:
617                 log_print("Unknown command passed to DLM device : %d\n",
618                           kbuf->cmd);
619         }
620 
621  out_free:
622         kfree(kbuf);
623         return error;
624 }
625 
626 /* Every process that opens the lockspace device has its own "proc" structure
627    hanging off the open file that's used to keep track of locks owned by the
628    process and asts that need to be delivered to the process. */
629 
630 static int device_open(struct inode *inode, struct file *file)
631 {
632         struct dlm_user_proc *proc;
633         struct dlm_ls *ls;
634 
635         ls = dlm_find_lockspace_device(iminor(inode));
636         if (!ls)
637                 return -ENOENT;
638 
639         proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
640         if (!proc) {
641                 dlm_put_lockspace(ls);
642                 return -ENOMEM;
643         }
644 
645         proc->lockspace = ls->ls_local_handle;
646         INIT_LIST_HEAD(&proc->asts);
647         INIT_LIST_HEAD(&proc->locks);
648         INIT_LIST_HEAD(&proc->unlocking);
649         spin_lock_init(&proc->asts_spin);
650         spin_lock_init(&proc->locks_spin);
651         init_waitqueue_head(&proc->wait);
652         file->private_data = proc;
653 
654         return 0;
655 }
656 
657 static int device_close(struct inode *inode, struct file *file)
658 {
659         struct dlm_user_proc *proc = file->private_data;
660         struct dlm_ls *ls;
661 
662         ls = dlm_find_lockspace_local(proc->lockspace);
663         if (!ls)
664                 return -ENOENT;
665 
666         set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
667 
668         dlm_clear_proc_locks(ls, proc);
669 
670         /* at this point no more lkb's should exist for this lockspace,
671            so there's no chance of dlm_user_add_ast() being called and
672            looking for lkb->ua->proc */
673 
674         kfree(proc);
675         file->private_data = NULL;
676 
677         dlm_put_lockspace(ls);
678         dlm_put_lockspace(ls);  /* for the find in device_open() */
679 
680         /* FIXME: AUTOFREE: if this ls is no longer used do
681            device_remove_lockspace() */
682 
683         return 0;
684 }
685 
686 static int copy_result_to_user(struct dlm_user_args *ua, int compat,
687                                uint32_t flags, int mode, int copy_lvb,
688                                char __user *buf, size_t count)
689 {
690 #ifdef CONFIG_COMPAT
691         struct dlm_lock_result32 result32;
692 #endif
693         struct dlm_lock_result result;
694         void *resultptr;
695         int error=0;
696         int len;
697         int struct_len;
698 
699         memset(&result, 0, sizeof(struct dlm_lock_result));
700         result.version[0] = DLM_DEVICE_VERSION_MAJOR;
701         result.version[1] = DLM_DEVICE_VERSION_MINOR;
702         result.version[2] = DLM_DEVICE_VERSION_PATCH;
703         memcpy(&result.lksb, &ua->lksb, offsetof(struct dlm_lksb, sb_lvbptr));
704         result.user_lksb = ua->user_lksb;
705 
706         /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
707            in a conversion unless the conversion is successful.  See code
708            in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
709            notes that a new blocking AST address and parameter are set even if
710            the conversion fails, so maybe we should just do that. */
711 
712         if (flags & DLM_CB_BAST) {
713                 result.user_astaddr = ua->bastaddr;
714                 result.user_astparam = ua->bastparam;
715                 result.bast_mode = mode;
716         } else {
717                 result.user_astaddr = ua->castaddr;
718                 result.user_astparam = ua->castparam;
719         }
720 
721 #ifdef CONFIG_COMPAT
722         if (compat)
723                 len = sizeof(struct dlm_lock_result32);
724         else
725 #endif
726                 len = sizeof(struct dlm_lock_result);
727         struct_len = len;
728 
729         /* copy lvb to userspace if there is one, it's been updated, and
730            the user buffer has space for it */
731 
732         if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
733                 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
734                                  DLM_USER_LVB_LEN)) {
735                         error = -EFAULT;
736                         goto out;
737                 }
738 
739                 result.lvb_offset = len;
740                 len += DLM_USER_LVB_LEN;
741         }
742 
743         result.length = len;
744         resultptr = &result;
745 #ifdef CONFIG_COMPAT
746         if (compat) {
747                 compat_output(&result, &result32);
748                 resultptr = &result32;
749         }
750 #endif
751 
752         if (copy_to_user(buf, resultptr, struct_len))
753                 error = -EFAULT;
754         else
755                 error = len;
756  out:
757         return error;
758 }
759 
760 static int copy_version_to_user(char __user *buf, size_t count)
761 {
762         struct dlm_device_version ver;
763 
764         memset(&ver, 0, sizeof(struct dlm_device_version));
765         ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
766         ver.version[1] = DLM_DEVICE_VERSION_MINOR;
767         ver.version[2] = DLM_DEVICE_VERSION_PATCH;
768 
769         if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
770                 return -EFAULT;
771         return sizeof(struct dlm_device_version);
772 }
773 
774 /* a read returns a single ast described in a struct dlm_lock_result */
775 
776 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
777                            loff_t *ppos)
778 {
779         struct dlm_user_proc *proc = file->private_data;
780         struct dlm_lkb *lkb;
781         DECLARE_WAITQUEUE(wait, current);
782         struct dlm_callback cb;
783         int rv, resid, copy_lvb = 0;
784         int old_mode, new_mode;
785 
786         if (count == sizeof(struct dlm_device_version)) {
787                 rv = copy_version_to_user(buf, count);
788                 return rv;
789         }
790 
791         if (!proc) {
792                 log_print("non-version read from control device %zu", count);
793                 return -EINVAL;
794         }
795 
796 #ifdef CONFIG_COMPAT
797         if (count < sizeof(struct dlm_lock_result32))
798 #else
799         if (count < sizeof(struct dlm_lock_result))
800 #endif
801                 return -EINVAL;
802 
803  try_another:
804 
805         /* do we really need this? can a read happen after a close? */
806         if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
807                 return -EINVAL;
808 
809         spin_lock(&proc->asts_spin);
810         if (list_empty(&proc->asts)) {
811                 if (file->f_flags & O_NONBLOCK) {
812                         spin_unlock(&proc->asts_spin);
813                         return -EAGAIN;
814                 }
815 
816                 add_wait_queue(&proc->wait, &wait);
817 
818         repeat:
819                 set_current_state(TASK_INTERRUPTIBLE);
820                 if (list_empty(&proc->asts) && !signal_pending(current)) {
821                         spin_unlock(&proc->asts_spin);
822                         schedule();
823                         spin_lock(&proc->asts_spin);
824                         goto repeat;
825                 }
826                 set_current_state(TASK_RUNNING);
827                 remove_wait_queue(&proc->wait, &wait);
828 
829                 if (signal_pending(current)) {
830                         spin_unlock(&proc->asts_spin);
831                         return -ERESTARTSYS;
832                 }
833         }
834 
835         /* if we empty lkb_callbacks, we don't want to unlock the spinlock
836            without removing lkb_cb_list; so empty lkb_cb_list is always
837            consistent with empty lkb_callbacks */
838 
839         lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
840 
841         /* rem_lkb_callback sets a new lkb_last_cast */
842         old_mode = lkb->lkb_last_cast.mode;
843 
844         rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
845         if (rv < 0) {
846                 /* this shouldn't happen; lkb should have been removed from
847                    list when resid was zero */
848                 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
849                 list_del_init(&lkb->lkb_cb_list);
850                 spin_unlock(&proc->asts_spin);
851                 /* removes ref for proc->asts, may cause lkb to be freed */
852                 dlm_put_lkb(lkb);
853                 goto try_another;
854         }
855         if (!resid)
856                 list_del_init(&lkb->lkb_cb_list);
857         spin_unlock(&proc->asts_spin);
858 
859         if (cb.flags & DLM_CB_SKIP) {
860                 /* removes ref for proc->asts, may cause lkb to be freed */
861                 if (!resid)
862                         dlm_put_lkb(lkb);
863                 goto try_another;
864         }
865 
866         if (cb.flags & DLM_CB_CAST) {
867                 new_mode = cb.mode;
868 
869                 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
870                     dlm_lvb_operations[old_mode + 1][new_mode + 1])
871                         copy_lvb = 1;
872 
873                 lkb->lkb_lksb->sb_status = cb.sb_status;
874                 lkb->lkb_lksb->sb_flags = cb.sb_flags;
875         }
876 
877         rv = copy_result_to_user(lkb->lkb_ua,
878                                  test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
879                                  cb.flags, cb.mode, copy_lvb, buf, count);
880 
881         /* removes ref for proc->asts, may cause lkb to be freed */
882         if (!resid)
883                 dlm_put_lkb(lkb);
884 
885         return rv;
886 }
887 
888 static __poll_t device_poll(struct file *file, poll_table *wait)
889 {
890         struct dlm_user_proc *proc = file->private_data;
891 
892         poll_wait(file, &proc->wait, wait);
893 
894         spin_lock(&proc->asts_spin);
895         if (!list_empty(&proc->asts)) {
896                 spin_unlock(&proc->asts_spin);
897                 return EPOLLIN | EPOLLRDNORM;
898         }
899         spin_unlock(&proc->asts_spin);
900         return 0;
901 }
902 
903 int dlm_user_daemon_available(void)
904 {
905         /* dlm_controld hasn't started (or, has started, but not
906            properly populated configfs) */
907 
908         if (!dlm_our_nodeid())
909                 return 0;
910 
911         /* This is to deal with versions of dlm_controld that don't
912            know about the monitor device.  We assume that if the
913            dlm_controld was started (above), but the monitor device
914            was never opened, that it's an old version.  dlm_controld
915            should open the monitor device before populating configfs. */
916 
917         if (dlm_monitor_unused)
918                 return 1;
919 
920         return atomic_read(&dlm_monitor_opened) ? 1 : 0;
921 }
922 
923 static int ctl_device_open(struct inode *inode, struct file *file)
924 {
925         file->private_data = NULL;
926         return 0;
927 }
928 
929 static int ctl_device_close(struct inode *inode, struct file *file)
930 {
931         return 0;
932 }
933 
934 static int monitor_device_open(struct inode *inode, struct file *file)
935 {
936         atomic_inc(&dlm_monitor_opened);
937         dlm_monitor_unused = 0;
938         return 0;
939 }
940 
941 static int monitor_device_close(struct inode *inode, struct file *file)
942 {
943         if (atomic_dec_and_test(&dlm_monitor_opened))
944                 dlm_stop_lockspaces();
945         return 0;
946 }
947 
948 static const struct file_operations device_fops = {
949         .open    = device_open,
950         .release = device_close,
951         .read    = device_read,
952         .write   = device_write,
953         .poll    = device_poll,
954         .owner   = THIS_MODULE,
955         .llseek  = noop_llseek,
956 };
957 
958 static const struct file_operations ctl_device_fops = {
959         .open    = ctl_device_open,
960         .release = ctl_device_close,
961         .read    = device_read,
962         .write   = device_write,
963         .owner   = THIS_MODULE,
964         .llseek  = noop_llseek,
965 };
966 
967 static struct miscdevice ctl_device = {
968         .name  = "dlm-control",
969         .fops  = &ctl_device_fops,
970         .minor = MISC_DYNAMIC_MINOR,
971 };
972 
973 static const struct file_operations monitor_device_fops = {
974         .open    = monitor_device_open,
975         .release = monitor_device_close,
976         .owner   = THIS_MODULE,
977         .llseek  = noop_llseek,
978 };
979 
980 static struct miscdevice monitor_device = {
981         .name  = "dlm-monitor",
982         .fops  = &monitor_device_fops,
983         .minor = MISC_DYNAMIC_MINOR,
984 };
985 
986 int __init dlm_user_init(void)
987 {
988         int error;
989 
990         atomic_set(&dlm_monitor_opened, 0);
991 
992         error = misc_register(&ctl_device);
993         if (error) {
994                 log_print("misc_register failed for control device");
995                 goto out;
996         }
997 
998         error = misc_register(&monitor_device);
999         if (error) {
1000                 log_print("misc_register failed for monitor device");
1001                 misc_deregister(&ctl_device);
1002         }
1003  out:
1004         return error;
1005 }
1006 
1007 void dlm_user_exit(void)
1008 {
1009         misc_deregister(&ctl_device);
1010         misc_deregister(&monitor_device);
1011 }
1012 
1013 

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