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

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  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/module.h>
 13 #include <linux/file.h>
 14 #include <linux/fs.h>
 15 #include <linux/poll.h>
 16 #include <linux/signal.h>
 17 #include <linux/spinlock.h>
 18 #include <linux/dlm.h>
 19 #include <linux/dlm_device.h>
 20 #include <linux/slab.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 
 29 static const char name_prefix[] = "dlm";
 30 static const struct file_operations device_fops;
 31 static atomic_t dlm_monitor_opened;
 32 static int dlm_monitor_unused = 1;
 33 
 34 #ifdef CONFIG_COMPAT
 35 
 36 struct dlm_lock_params32 {
 37         __u8 mode;
 38         __u8 namelen;
 39         __u16 unused;
 40         __u32 flags;
 41         __u32 lkid;
 42         __u32 parent;
 43         __u64 xid;
 44         __u64 timeout;
 45         __u32 castparam;
 46         __u32 castaddr;
 47         __u32 bastparam;
 48         __u32 bastaddr;
 49         __u32 lksb;
 50         char lvb[DLM_USER_LVB_LEN];
 51         char name[0];
 52 };
 53 
 54 struct dlm_write_request32 {
 55         __u32 version[3];
 56         __u8 cmd;
 57         __u8 is64bit;
 58         __u8 unused[2];
 59 
 60         union  {
 61                 struct dlm_lock_params32 lock;
 62                 struct dlm_lspace_params lspace;
 63                 struct dlm_purge_params purge;
 64         } i;
 65 };
 66 
 67 struct dlm_lksb32 {
 68         __u32 sb_status;
 69         __u32 sb_lkid;
 70         __u8 sb_flags;
 71         __u32 sb_lvbptr;
 72 };
 73 
 74 struct dlm_lock_result32 {
 75         __u32 version[3];
 76         __u32 length;
 77         __u32 user_astaddr;
 78         __u32 user_astparam;
 79         __u32 user_lksb;
 80         struct dlm_lksb32 lksb;
 81         __u8 bast_mode;
 82         __u8 unused[3];
 83         /* Offsets may be zero if no data is present */
 84         __u32 lvb_offset;
 85 };
 86 
 87 static void compat_input(struct dlm_write_request *kb,
 88                          struct dlm_write_request32 *kb32,
 89                          int namelen)
 90 {
 91         kb->version[0] = kb32->version[0];
 92         kb->version[1] = kb32->version[1];
 93         kb->version[2] = kb32->version[2];
 94 
 95         kb->cmd = kb32->cmd;
 96         kb->is64bit = kb32->is64bit;
 97         if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
 98             kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
 99                 kb->i.lspace.flags = kb32->i.lspace.flags;
100                 kb->i.lspace.minor = kb32->i.lspace.minor;
101                 memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
102         } else if (kb->cmd == DLM_USER_PURGE) {
103                 kb->i.purge.nodeid = kb32->i.purge.nodeid;
104                 kb->i.purge.pid = kb32->i.purge.pid;
105         } else {
106                 kb->i.lock.mode = kb32->i.lock.mode;
107                 kb->i.lock.namelen = kb32->i.lock.namelen;
108                 kb->i.lock.flags = kb32->i.lock.flags;
109                 kb->i.lock.lkid = kb32->i.lock.lkid;
110                 kb->i.lock.parent = kb32->i.lock.parent;
111                 kb->i.lock.xid = kb32->i.lock.xid;
112                 kb->i.lock.timeout = kb32->i.lock.timeout;
113                 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
114                 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
115                 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
116                 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
117                 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
118                 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
119                 memcpy(kb->i.lock.name, kb32->i.lock.name, namelen);
120         }
121 }
122 
123 static void compat_output(struct dlm_lock_result *res,
124                           struct dlm_lock_result32 *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         int error = -ENOMEM;
242 
243         ls = dlm_find_lockspace_local(proc->lockspace);
244         if (!ls)
245                 return -ENOENT;
246 
247         if (!params->castaddr || !params->lksb) {
248                 error = -EINVAL;
249                 goto out;
250         }
251 
252         ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
253         if (!ua)
254                 goto out;
255         ua->proc = proc;
256         ua->user_lksb = params->lksb;
257         ua->castparam = params->castparam;
258         ua->castaddr = params->castaddr;
259         ua->bastparam = params->bastparam;
260         ua->bastaddr = params->bastaddr;
261         ua->xid = params->xid;
262 
263         if (params->flags & DLM_LKF_CONVERT)
264                 error = dlm_user_convert(ls, ua,
265                                          params->mode, params->flags,
266                                          params->lkid, params->lvb,
267                                          (unsigned long) params->timeout);
268         else {
269                 error = dlm_user_request(ls, ua,
270                                          params->mode, params->flags,
271                                          params->name, params->namelen,
272                                          (unsigned long) params->timeout);
273                 if (!error)
274                         error = ua->lksb.sb_lkid;
275         }
276  out:
277         dlm_put_lockspace(ls);
278         return error;
279 }
280 
281 static int device_user_unlock(struct dlm_user_proc *proc,
282                               struct dlm_lock_params *params)
283 {
284         struct dlm_ls *ls;
285         struct dlm_user_args *ua;
286         int error = -ENOMEM;
287 
288         ls = dlm_find_lockspace_local(proc->lockspace);
289         if (!ls)
290                 return -ENOENT;
291 
292         ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
293         if (!ua)
294                 goto out;
295         ua->proc = proc;
296         ua->user_lksb = params->lksb;
297         ua->castparam = params->castparam;
298         ua->castaddr = params->castaddr;
299 
300         if (params->flags & DLM_LKF_CANCEL)
301                 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
302         else
303                 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
304                                         params->lvb);
305  out:
306         dlm_put_lockspace(ls);
307         return error;
308 }
309 
310 static int device_user_deadlock(struct dlm_user_proc *proc,
311                                 struct dlm_lock_params *params)
312 {
313         struct dlm_ls *ls;
314         int error;
315 
316         ls = dlm_find_lockspace_local(proc->lockspace);
317         if (!ls)
318                 return -ENOENT;
319 
320         error = dlm_user_deadlock(ls, params->flags, params->lkid);
321 
322         dlm_put_lockspace(ls);
323         return error;
324 }
325 
326 static int dlm_device_register(struct dlm_ls *ls, char *name)
327 {
328         int error, len;
329 
330         /* The device is already registered.  This happens when the
331            lockspace is created multiple times from userspace. */
332         if (ls->ls_device.name)
333                 return 0;
334 
335         error = -ENOMEM;
336         len = strlen(name) + strlen(name_prefix) + 2;
337         ls->ls_device.name = kzalloc(len, GFP_NOFS);
338         if (!ls->ls_device.name)
339                 goto fail;
340 
341         snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
342                  name);
343         ls->ls_device.fops = &device_fops;
344         ls->ls_device.minor = MISC_DYNAMIC_MINOR;
345 
346         error = misc_register(&ls->ls_device);
347         if (error) {
348                 kfree(ls->ls_device.name);
349         }
350 fail:
351         return error;
352 }
353 
354 int dlm_device_deregister(struct dlm_ls *ls)
355 {
356         int error;
357 
358         /* The device is not registered.  This happens when the lockspace
359            was never used from userspace, or when device_create_lockspace()
360            calls dlm_release_lockspace() after the register fails. */
361         if (!ls->ls_device.name)
362                 return 0;
363 
364         error = misc_deregister(&ls->ls_device);
365         if (!error)
366                 kfree(ls->ls_device.name);
367         return error;
368 }
369 
370 static int device_user_purge(struct dlm_user_proc *proc,
371                              struct dlm_purge_params *params)
372 {
373         struct dlm_ls *ls;
374         int error;
375 
376         ls = dlm_find_lockspace_local(proc->lockspace);
377         if (!ls)
378                 return -ENOENT;
379 
380         error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
381 
382         dlm_put_lockspace(ls);
383         return error;
384 }
385 
386 static int device_create_lockspace(struct dlm_lspace_params *params)
387 {
388         dlm_lockspace_t *lockspace;
389         struct dlm_ls *ls;
390         int error;
391 
392         if (!capable(CAP_SYS_ADMIN))
393                 return -EPERM;
394 
395         error = dlm_new_lockspace(params->name, NULL, params->flags,
396                                   DLM_USER_LVB_LEN, NULL, NULL, NULL,
397                                   &lockspace);
398         if (error)
399                 return error;
400 
401         ls = dlm_find_lockspace_local(lockspace);
402         if (!ls)
403                 return -ENOENT;
404 
405         error = dlm_device_register(ls, params->name);
406         dlm_put_lockspace(ls);
407 
408         if (error)
409                 dlm_release_lockspace(lockspace, 0);
410         else
411                 error = ls->ls_device.minor;
412 
413         return error;
414 }
415 
416 static int device_remove_lockspace(struct dlm_lspace_params *params)
417 {
418         dlm_lockspace_t *lockspace;
419         struct dlm_ls *ls;
420         int error, force = 0;
421 
422         if (!capable(CAP_SYS_ADMIN))
423                 return -EPERM;
424 
425         ls = dlm_find_lockspace_device(params->minor);
426         if (!ls)
427                 return -ENOENT;
428 
429         if (params->flags & DLM_USER_LSFLG_FORCEFREE)
430                 force = 2;
431 
432         lockspace = ls->ls_local_handle;
433         dlm_put_lockspace(ls);
434 
435         /* The final dlm_release_lockspace waits for references to go to
436            zero, so all processes will need to close their device for the
437            ls before the release will proceed.  release also calls the
438            device_deregister above.  Converting a positive return value
439            from release to zero means that userspace won't know when its
440            release was the final one, but it shouldn't need to know. */
441 
442         error = dlm_release_lockspace(lockspace, force);
443         if (error > 0)
444                 error = 0;
445         return error;
446 }
447 
448 /* Check the user's version matches ours */
449 static int check_version(struct dlm_write_request *req)
450 {
451         if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
452             (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
453              req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
454 
455                 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
456                        "user (%d.%d.%d) kernel (%d.%d.%d)\n",
457                        current->comm,
458                        task_pid_nr(current),
459                        req->version[0],
460                        req->version[1],
461                        req->version[2],
462                        DLM_DEVICE_VERSION_MAJOR,
463                        DLM_DEVICE_VERSION_MINOR,
464                        DLM_DEVICE_VERSION_PATCH);
465                 return -EINVAL;
466         }
467         return 0;
468 }
469 
470 /*
471  * device_write
472  *
473  *   device_user_lock
474  *     dlm_user_request -> request_lock
475  *     dlm_user_convert -> convert_lock
476  *
477  *   device_user_unlock
478  *     dlm_user_unlock -> unlock_lock
479  *     dlm_user_cancel -> cancel_lock
480  *
481  *   device_create_lockspace
482  *     dlm_new_lockspace
483  *
484  *   device_remove_lockspace
485  *     dlm_release_lockspace
486  */
487 
488 /* a write to a lockspace device is a lock or unlock request, a write
489    to the control device is to create/remove a lockspace */
490 
491 static ssize_t device_write(struct file *file, const char __user *buf,
492                             size_t count, loff_t *ppos)
493 {
494         struct dlm_user_proc *proc = file->private_data;
495         struct dlm_write_request *kbuf;
496         sigset_t tmpsig, allsigs;
497         int error;
498 
499 #ifdef CONFIG_COMPAT
500         if (count < sizeof(struct dlm_write_request32))
501 #else
502         if (count < sizeof(struct dlm_write_request))
503 #endif
504                 return -EINVAL;
505 
506         /*
507          * can't compare against COMPAT/dlm_write_request32 because
508          * we don't yet know if is64bit is zero
509          */
510         if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
511                 return -EINVAL;
512 
513         kbuf = kzalloc(count + 1, GFP_NOFS);
514         if (!kbuf)
515                 return -ENOMEM;
516 
517         if (copy_from_user(kbuf, buf, count)) {
518                 error = -EFAULT;
519                 goto out_free;
520         }
521 
522         if (check_version(kbuf)) {
523                 error = -EBADE;
524                 goto out_free;
525         }
526 
527 #ifdef CONFIG_COMPAT
528         if (!kbuf->is64bit) {
529                 struct dlm_write_request32 *k32buf;
530                 int namelen = 0;
531 
532                 if (count > sizeof(struct dlm_write_request32))
533                         namelen = count - sizeof(struct dlm_write_request32);
534 
535                 k32buf = (struct dlm_write_request32 *)kbuf;
536 
537                 /* add 1 after namelen so that the name string is terminated */
538                 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
539                                GFP_NOFS);
540                 if (!kbuf) {
541                         kfree(k32buf);
542                         return -ENOMEM;
543                 }
544 
545                 if (proc)
546                         set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
547 
548                 compat_input(kbuf, k32buf, namelen);
549                 kfree(k32buf);
550         }
551 #endif
552 
553         /* do we really need this? can a write happen after a close? */
554         if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
555             (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
556                 error = -EINVAL;
557                 goto out_free;
558         }
559 
560         sigfillset(&allsigs);
561         sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
562 
563         error = -EINVAL;
564 
565         switch (kbuf->cmd)
566         {
567         case DLM_USER_LOCK:
568                 if (!proc) {
569                         log_print("no locking on control device");
570                         goto out_sig;
571                 }
572                 error = device_user_lock(proc, &kbuf->i.lock);
573                 break;
574 
575         case DLM_USER_UNLOCK:
576                 if (!proc) {
577                         log_print("no locking on control device");
578                         goto out_sig;
579                 }
580                 error = device_user_unlock(proc, &kbuf->i.lock);
581                 break;
582 
583         case DLM_USER_DEADLOCK:
584                 if (!proc) {
585                         log_print("no locking on control device");
586                         goto out_sig;
587                 }
588                 error = device_user_deadlock(proc, &kbuf->i.lock);
589                 break;
590 
591         case DLM_USER_CREATE_LOCKSPACE:
592                 if (proc) {
593                         log_print("create/remove only on control device");
594                         goto out_sig;
595                 }
596                 error = device_create_lockspace(&kbuf->i.lspace);
597                 break;
598 
599         case DLM_USER_REMOVE_LOCKSPACE:
600                 if (proc) {
601                         log_print("create/remove only on control device");
602                         goto out_sig;
603                 }
604                 error = device_remove_lockspace(&kbuf->i.lspace);
605                 break;
606 
607         case DLM_USER_PURGE:
608                 if (!proc) {
609                         log_print("no locking on control device");
610                         goto out_sig;
611                 }
612                 error = device_user_purge(proc, &kbuf->i.purge);
613                 break;
614 
615         default:
616                 log_print("Unknown command passed to DLM device : %d\n",
617                           kbuf->cmd);
618         }
619 
620  out_sig:
621         sigprocmask(SIG_SETMASK, &tmpsig, NULL);
622  out_free:
623         kfree(kbuf);
624         return error;
625 }
626 
627 /* Every process that opens the lockspace device has its own "proc" structure
628    hanging off the open file that's used to keep track of locks owned by the
629    process and asts that need to be delivered to the process. */
630 
631 static int device_open(struct inode *inode, struct file *file)
632 {
633         struct dlm_user_proc *proc;
634         struct dlm_ls *ls;
635 
636         ls = dlm_find_lockspace_device(iminor(inode));
637         if (!ls)
638                 return -ENOENT;
639 
640         proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
641         if (!proc) {
642                 dlm_put_lockspace(ls);
643                 return -ENOMEM;
644         }
645 
646         proc->lockspace = ls->ls_local_handle;
647         INIT_LIST_HEAD(&proc->asts);
648         INIT_LIST_HEAD(&proc->locks);
649         INIT_LIST_HEAD(&proc->unlocking);
650         spin_lock_init(&proc->asts_spin);
651         spin_lock_init(&proc->locks_spin);
652         init_waitqueue_head(&proc->wait);
653         file->private_data = proc;
654 
655         return 0;
656 }
657 
658 static int device_close(struct inode *inode, struct file *file)
659 {
660         struct dlm_user_proc *proc = file->private_data;
661         struct dlm_ls *ls;
662         sigset_t tmpsig, allsigs;
663 
664         ls = dlm_find_lockspace_local(proc->lockspace);
665         if (!ls)
666                 return -ENOENT;
667 
668         sigfillset(&allsigs);
669         sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
670 
671         set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
672 
673         dlm_clear_proc_locks(ls, proc);
674 
675         /* at this point no more lkb's should exist for this lockspace,
676            so there's no chance of dlm_user_add_ast() being called and
677            looking for lkb->ua->proc */
678 
679         kfree(proc);
680         file->private_data = NULL;
681 
682         dlm_put_lockspace(ls);
683         dlm_put_lockspace(ls);  /* for the find in device_open() */
684 
685         /* FIXME: AUTOFREE: if this ls is no longer used do
686            device_remove_lockspace() */
687 
688         sigprocmask(SIG_SETMASK, &tmpsig, NULL);
689         recalc_sigpending();
690 
691         return 0;
692 }
693 
694 static int copy_result_to_user(struct dlm_user_args *ua, int compat,
695                                uint32_t flags, int mode, int copy_lvb,
696                                char __user *buf, size_t count)
697 {
698 #ifdef CONFIG_COMPAT
699         struct dlm_lock_result32 result32;
700 #endif
701         struct dlm_lock_result result;
702         void *resultptr;
703         int error=0;
704         int len;
705         int struct_len;
706 
707         memset(&result, 0, sizeof(struct dlm_lock_result));
708         result.version[0] = DLM_DEVICE_VERSION_MAJOR;
709         result.version[1] = DLM_DEVICE_VERSION_MINOR;
710         result.version[2] = DLM_DEVICE_VERSION_PATCH;
711         memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
712         result.user_lksb = ua->user_lksb;
713 
714         /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
715            in a conversion unless the conversion is successful.  See code
716            in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
717            notes that a new blocking AST address and parameter are set even if
718            the conversion fails, so maybe we should just do that. */
719 
720         if (flags & DLM_CB_BAST) {
721                 result.user_astaddr = ua->bastaddr;
722                 result.user_astparam = ua->bastparam;
723                 result.bast_mode = mode;
724         } else {
725                 result.user_astaddr = ua->castaddr;
726                 result.user_astparam = ua->castparam;
727         }
728 
729 #ifdef CONFIG_COMPAT
730         if (compat)
731                 len = sizeof(struct dlm_lock_result32);
732         else
733 #endif
734                 len = sizeof(struct dlm_lock_result);
735         struct_len = len;
736 
737         /* copy lvb to userspace if there is one, it's been updated, and
738            the user buffer has space for it */
739 
740         if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
741                 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
742                                  DLM_USER_LVB_LEN)) {
743                         error = -EFAULT;
744                         goto out;
745                 }
746 
747                 result.lvb_offset = len;
748                 len += DLM_USER_LVB_LEN;
749         }
750 
751         result.length = len;
752         resultptr = &result;
753 #ifdef CONFIG_COMPAT
754         if (compat) {
755                 compat_output(&result, &result32);
756                 resultptr = &result32;
757         }
758 #endif
759 
760         if (copy_to_user(buf, resultptr, struct_len))
761                 error = -EFAULT;
762         else
763                 error = len;
764  out:
765         return error;
766 }
767 
768 static int copy_version_to_user(char __user *buf, size_t count)
769 {
770         struct dlm_device_version ver;
771 
772         memset(&ver, 0, sizeof(struct dlm_device_version));
773         ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
774         ver.version[1] = DLM_DEVICE_VERSION_MINOR;
775         ver.version[2] = DLM_DEVICE_VERSION_PATCH;
776 
777         if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
778                 return -EFAULT;
779         return sizeof(struct dlm_device_version);
780 }
781 
782 /* a read returns a single ast described in a struct dlm_lock_result */
783 
784 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
785                            loff_t *ppos)
786 {
787         struct dlm_user_proc *proc = file->private_data;
788         struct dlm_lkb *lkb;
789         DECLARE_WAITQUEUE(wait, current);
790         struct dlm_callback cb;
791         int rv, resid, copy_lvb = 0;
792 
793         if (count == sizeof(struct dlm_device_version)) {
794                 rv = copy_version_to_user(buf, count);
795                 return rv;
796         }
797 
798         if (!proc) {
799                 log_print("non-version read from control device %zu", count);
800                 return -EINVAL;
801         }
802 
803 #ifdef CONFIG_COMPAT
804         if (count < sizeof(struct dlm_lock_result32))
805 #else
806         if (count < sizeof(struct dlm_lock_result))
807 #endif
808                 return -EINVAL;
809 
810  try_another:
811 
812         /* do we really need this? can a read happen after a close? */
813         if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
814                 return -EINVAL;
815 
816         spin_lock(&proc->asts_spin);
817         if (list_empty(&proc->asts)) {
818                 if (file->f_flags & O_NONBLOCK) {
819                         spin_unlock(&proc->asts_spin);
820                         return -EAGAIN;
821                 }
822 
823                 add_wait_queue(&proc->wait, &wait);
824 
825         repeat:
826                 set_current_state(TASK_INTERRUPTIBLE);
827                 if (list_empty(&proc->asts) && !signal_pending(current)) {
828                         spin_unlock(&proc->asts_spin);
829                         schedule();
830                         spin_lock(&proc->asts_spin);
831                         goto repeat;
832                 }
833                 set_current_state(TASK_RUNNING);
834                 remove_wait_queue(&proc->wait, &wait);
835 
836                 if (signal_pending(current)) {
837                         spin_unlock(&proc->asts_spin);
838                         return -ERESTARTSYS;
839                 }
840         }
841 
842         /* if we empty lkb_callbacks, we don't want to unlock the spinlock
843            without removing lkb_cb_list; so empty lkb_cb_list is always
844            consistent with empty lkb_callbacks */
845 
846         lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
847 
848         rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
849         if (rv < 0) {
850                 /* this shouldn't happen; lkb should have been removed from
851                    list when resid was zero */
852                 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
853                 list_del_init(&lkb->lkb_cb_list);
854                 spin_unlock(&proc->asts_spin);
855                 /* removes ref for proc->asts, may cause lkb to be freed */
856                 dlm_put_lkb(lkb);
857                 goto try_another;
858         }
859         if (!resid)
860                 list_del_init(&lkb->lkb_cb_list);
861         spin_unlock(&proc->asts_spin);
862 
863         if (cb.flags & DLM_CB_SKIP) {
864                 /* removes ref for proc->asts, may cause lkb to be freed */
865                 if (!resid)
866                         dlm_put_lkb(lkb);
867                 goto try_another;
868         }
869 
870         if (cb.flags & DLM_CB_CAST) {
871                 int old_mode, new_mode;
872 
873                 old_mode = lkb->lkb_last_cast.mode;
874                 new_mode = cb.mode;
875 
876                 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
877                     dlm_lvb_operations[old_mode + 1][new_mode + 1])
878                         copy_lvb = 1;
879 
880                 lkb->lkb_lksb->sb_status = cb.sb_status;
881                 lkb->lkb_lksb->sb_flags = cb.sb_flags;
882         }
883 
884         rv = copy_result_to_user(lkb->lkb_ua,
885                                  test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
886                                  cb.flags, cb.mode, copy_lvb, buf, count);
887 
888         /* removes ref for proc->asts, may cause lkb to be freed */
889         if (!resid)
890                 dlm_put_lkb(lkb);
891 
892         return rv;
893 }
894 
895 static unsigned int device_poll(struct file *file, poll_table *wait)
896 {
897         struct dlm_user_proc *proc = file->private_data;
898 
899         poll_wait(file, &proc->wait, wait);
900 
901         spin_lock(&proc->asts_spin);
902         if (!list_empty(&proc->asts)) {
903                 spin_unlock(&proc->asts_spin);
904                 return POLLIN | POLLRDNORM;
905         }
906         spin_unlock(&proc->asts_spin);
907         return 0;
908 }
909 
910 int dlm_user_daemon_available(void)
911 {
912         /* dlm_controld hasn't started (or, has started, but not
913            properly populated configfs) */
914 
915         if (!dlm_our_nodeid())
916                 return 0;
917 
918         /* This is to deal with versions of dlm_controld that don't
919            know about the monitor device.  We assume that if the
920            dlm_controld was started (above), but the monitor device
921            was never opened, that it's an old version.  dlm_controld
922            should open the monitor device before populating configfs. */
923 
924         if (dlm_monitor_unused)
925                 return 1;
926 
927         return atomic_read(&dlm_monitor_opened) ? 1 : 0;
928 }
929 
930 static int ctl_device_open(struct inode *inode, struct file *file)
931 {
932         file->private_data = NULL;
933         return 0;
934 }
935 
936 static int ctl_device_close(struct inode *inode, struct file *file)
937 {
938         return 0;
939 }
940 
941 static int monitor_device_open(struct inode *inode, struct file *file)
942 {
943         atomic_inc(&dlm_monitor_opened);
944         dlm_monitor_unused = 0;
945         return 0;
946 }
947 
948 static int monitor_device_close(struct inode *inode, struct file *file)
949 {
950         if (atomic_dec_and_test(&dlm_monitor_opened))
951                 dlm_stop_lockspaces();
952         return 0;
953 }
954 
955 static const struct file_operations device_fops = {
956         .open    = device_open,
957         .release = device_close,
958         .read    = device_read,
959         .write   = device_write,
960         .poll    = device_poll,
961         .owner   = THIS_MODULE,
962         .llseek  = noop_llseek,
963 };
964 
965 static const struct file_operations ctl_device_fops = {
966         .open    = ctl_device_open,
967         .release = ctl_device_close,
968         .read    = device_read,
969         .write   = device_write,
970         .owner   = THIS_MODULE,
971         .llseek  = noop_llseek,
972 };
973 
974 static struct miscdevice ctl_device = {
975         .name  = "dlm-control",
976         .fops  = &ctl_device_fops,
977         .minor = MISC_DYNAMIC_MINOR,
978 };
979 
980 static const struct file_operations monitor_device_fops = {
981         .open    = monitor_device_open,
982         .release = monitor_device_close,
983         .owner   = THIS_MODULE,
984         .llseek  = noop_llseek,
985 };
986 
987 static struct miscdevice monitor_device = {
988         .name  = "dlm-monitor",
989         .fops  = &monitor_device_fops,
990         .minor = MISC_DYNAMIC_MINOR,
991 };
992 
993 int __init dlm_user_init(void)
994 {
995         int error;
996 
997         atomic_set(&dlm_monitor_opened, 0);
998 
999         error = misc_register(&ctl_device);
1000         if (error) {
1001                 log_print("misc_register failed for control device");
1002                 goto out;
1003         }
1004 
1005         error = misc_register(&monitor_device);
1006         if (error) {
1007                 log_print("misc_register failed for monitor device");
1008                 misc_deregister(&ctl_device);
1009         }
1010  out:
1011         return error;
1012 }
1013 
1014 void dlm_user_exit(void)
1015 {
1016         misc_deregister(&ctl_device);
1017         misc_deregister(&monitor_device);
1018 }
1019 
1020 

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