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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/file.h>
 13 #include <linux/fs.h>
 14 #include <linux/poll.h>
 15 #include <linux/signal.h>
 16 #include <linux/spinlock.h>
 17 #include <linux/dlm.h>
 18 #include <linux/dlm_device.h>
 19 #include <linux/slab.h>
 20 #include <linux/sched/signal.h>
 21 
 22 #include "dlm_internal.h"
 23 #include "lockspace.h"
 24 #include "lock.h"
 25 #include "lvb_table.h"
 26 #include "user.h"
 27 #include "ast.h"
 28 
 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         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         }
359 fail:
360         return error;
361 }
362 
363 int dlm_device_deregister(struct dlm_ls *ls)
364 {
365         /* The device is not registered.  This happens when the lockspace
366            was never used from userspace, or when device_create_lockspace()
367            calls dlm_release_lockspace() after the register fails. */
368         if (!ls->ls_device.name)
369                 return 0;
370 
371         misc_deregister(&ls->ls_device);
372         kfree(ls->ls_device.name);
373         return 0;
374 }
375 
376 static int device_user_purge(struct dlm_user_proc *proc,
377                              struct dlm_purge_params *params)
378 {
379         struct dlm_ls *ls;
380         int error;
381 
382         ls = dlm_find_lockspace_local(proc->lockspace);
383         if (!ls)
384                 return -ENOENT;
385 
386         error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
387 
388         dlm_put_lockspace(ls);
389         return error;
390 }
391 
392 static int device_create_lockspace(struct dlm_lspace_params *params)
393 {
394         dlm_lockspace_t *lockspace;
395         struct dlm_ls *ls;
396         int error;
397 
398         if (!capable(CAP_SYS_ADMIN))
399                 return -EPERM;
400 
401         error = dlm_new_lockspace(params->name, NULL, params->flags,
402                                   DLM_USER_LVB_LEN, NULL, NULL, NULL,
403                                   &lockspace);
404         if (error)
405                 return error;
406 
407         ls = dlm_find_lockspace_local(lockspace);
408         if (!ls)
409                 return -ENOENT;
410 
411         error = dlm_device_register(ls, params->name);
412         dlm_put_lockspace(ls);
413 
414         if (error)
415                 dlm_release_lockspace(lockspace, 0);
416         else
417                 error = ls->ls_device.minor;
418 
419         return error;
420 }
421 
422 static int device_remove_lockspace(struct dlm_lspace_params *params)
423 {
424         dlm_lockspace_t *lockspace;
425         struct dlm_ls *ls;
426         int error, force = 0;
427 
428         if (!capable(CAP_SYS_ADMIN))
429                 return -EPERM;
430 
431         ls = dlm_find_lockspace_device(params->minor);
432         if (!ls)
433                 return -ENOENT;
434 
435         if (params->flags & DLM_USER_LSFLG_FORCEFREE)
436                 force = 2;
437 
438         lockspace = ls->ls_local_handle;
439         dlm_put_lockspace(ls);
440 
441         /* The final dlm_release_lockspace waits for references to go to
442            zero, so all processes will need to close their device for the
443            ls before the release will proceed.  release also calls the
444            device_deregister above.  Converting a positive return value
445            from release to zero means that userspace won't know when its
446            release was the final one, but it shouldn't need to know. */
447 
448         error = dlm_release_lockspace(lockspace, force);
449         if (error > 0)
450                 error = 0;
451         return error;
452 }
453 
454 /* Check the user's version matches ours */
455 static int check_version(struct dlm_write_request *req)
456 {
457         if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
458             (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
459              req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
460 
461                 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
462                        "user (%d.%d.%d) kernel (%d.%d.%d)\n",
463                        current->comm,
464                        task_pid_nr(current),
465                        req->version[0],
466                        req->version[1],
467                        req->version[2],
468                        DLM_DEVICE_VERSION_MAJOR,
469                        DLM_DEVICE_VERSION_MINOR,
470                        DLM_DEVICE_VERSION_PATCH);
471                 return -EINVAL;
472         }
473         return 0;
474 }
475 
476 /*
477  * device_write
478  *
479  *   device_user_lock
480  *     dlm_user_request -> request_lock
481  *     dlm_user_convert -> convert_lock
482  *
483  *   device_user_unlock
484  *     dlm_user_unlock -> unlock_lock
485  *     dlm_user_cancel -> cancel_lock
486  *
487  *   device_create_lockspace
488  *     dlm_new_lockspace
489  *
490  *   device_remove_lockspace
491  *     dlm_release_lockspace
492  */
493 
494 /* a write to a lockspace device is a lock or unlock request, a write
495    to the control device is to create/remove a lockspace */
496 
497 static ssize_t device_write(struct file *file, const char __user *buf,
498                             size_t count, loff_t *ppos)
499 {
500         struct dlm_user_proc *proc = file->private_data;
501         struct dlm_write_request *kbuf;
502         int error;
503 
504 #ifdef CONFIG_COMPAT
505         if (count < sizeof(struct dlm_write_request32))
506 #else
507         if (count < sizeof(struct dlm_write_request))
508 #endif
509                 return -EINVAL;
510 
511         /*
512          * can't compare against COMPAT/dlm_write_request32 because
513          * we don't yet know if is64bit is zero
514          */
515         if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
516                 return -EINVAL;
517 
518         kbuf = memdup_user_nul(buf, count);
519         if (IS_ERR(kbuf))
520                 return PTR_ERR(kbuf);
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         error = -EINVAL;
561 
562         switch (kbuf->cmd)
563         {
564         case DLM_USER_LOCK:
565                 if (!proc) {
566                         log_print("no locking on control device");
567                         goto out_free;
568                 }
569                 error = device_user_lock(proc, &kbuf->i.lock);
570                 break;
571 
572         case DLM_USER_UNLOCK:
573                 if (!proc) {
574                         log_print("no locking on control device");
575                         goto out_free;
576                 }
577                 error = device_user_unlock(proc, &kbuf->i.lock);
578                 break;
579 
580         case DLM_USER_DEADLOCK:
581                 if (!proc) {
582                         log_print("no locking on control device");
583                         goto out_free;
584                 }
585                 error = device_user_deadlock(proc, &kbuf->i.lock);
586                 break;
587 
588         case DLM_USER_CREATE_LOCKSPACE:
589                 if (proc) {
590                         log_print("create/remove only on control device");
591                         goto out_free;
592                 }
593                 error = device_create_lockspace(&kbuf->i.lspace);
594                 break;
595 
596         case DLM_USER_REMOVE_LOCKSPACE:
597                 if (proc) {
598                         log_print("create/remove only on control device");
599                         goto out_free;
600                 }
601                 error = device_remove_lockspace(&kbuf->i.lspace);
602                 break;
603 
604         case DLM_USER_PURGE:
605                 if (!proc) {
606                         log_print("no locking on control device");
607                         goto out_free;
608                 }
609                 error = device_user_purge(proc, &kbuf->i.purge);
610                 break;
611 
612         default:
613                 log_print("Unknown command passed to DLM device : %d\n",
614                           kbuf->cmd);
615         }
616 
617  out_free:
618         kfree(kbuf);
619         return error;
620 }
621 
622 /* Every process that opens the lockspace device has its own "proc" structure
623    hanging off the open file that's used to keep track of locks owned by the
624    process and asts that need to be delivered to the process. */
625 
626 static int device_open(struct inode *inode, struct file *file)
627 {
628         struct dlm_user_proc *proc;
629         struct dlm_ls *ls;
630 
631         ls = dlm_find_lockspace_device(iminor(inode));
632         if (!ls)
633                 return -ENOENT;
634 
635         proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
636         if (!proc) {
637                 dlm_put_lockspace(ls);
638                 return -ENOMEM;
639         }
640 
641         proc->lockspace = ls->ls_local_handle;
642         INIT_LIST_HEAD(&proc->asts);
643         INIT_LIST_HEAD(&proc->locks);
644         INIT_LIST_HEAD(&proc->unlocking);
645         spin_lock_init(&proc->asts_spin);
646         spin_lock_init(&proc->locks_spin);
647         init_waitqueue_head(&proc->wait);
648         file->private_data = proc;
649 
650         return 0;
651 }
652 
653 static int device_close(struct inode *inode, struct file *file)
654 {
655         struct dlm_user_proc *proc = file->private_data;
656         struct dlm_ls *ls;
657 
658         ls = dlm_find_lockspace_local(proc->lockspace);
659         if (!ls)
660                 return -ENOENT;
661 
662         set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
663 
664         dlm_clear_proc_locks(ls, proc);
665 
666         /* at this point no more lkb's should exist for this lockspace,
667            so there's no chance of dlm_user_add_ast() being called and
668            looking for lkb->ua->proc */
669 
670         kfree(proc);
671         file->private_data = NULL;
672 
673         dlm_put_lockspace(ls);
674         dlm_put_lockspace(ls);  /* for the find in device_open() */
675 
676         /* FIXME: AUTOFREE: if this ls is no longer used do
677            device_remove_lockspace() */
678 
679         return 0;
680 }
681 
682 static int copy_result_to_user(struct dlm_user_args *ua, int compat,
683                                uint32_t flags, int mode, int copy_lvb,
684                                char __user *buf, size_t count)
685 {
686 #ifdef CONFIG_COMPAT
687         struct dlm_lock_result32 result32;
688 #endif
689         struct dlm_lock_result result;
690         void *resultptr;
691         int error=0;
692         int len;
693         int struct_len;
694 
695         memset(&result, 0, sizeof(struct dlm_lock_result));
696         result.version[0] = DLM_DEVICE_VERSION_MAJOR;
697         result.version[1] = DLM_DEVICE_VERSION_MINOR;
698         result.version[2] = DLM_DEVICE_VERSION_PATCH;
699         memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
700         result.user_lksb = ua->user_lksb;
701 
702         /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
703            in a conversion unless the conversion is successful.  See code
704            in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
705            notes that a new blocking AST address and parameter are set even if
706            the conversion fails, so maybe we should just do that. */
707 
708         if (flags & DLM_CB_BAST) {
709                 result.user_astaddr = ua->bastaddr;
710                 result.user_astparam = ua->bastparam;
711                 result.bast_mode = mode;
712         } else {
713                 result.user_astaddr = ua->castaddr;
714                 result.user_astparam = ua->castparam;
715         }
716 
717 #ifdef CONFIG_COMPAT
718         if (compat)
719                 len = sizeof(struct dlm_lock_result32);
720         else
721 #endif
722                 len = sizeof(struct dlm_lock_result);
723         struct_len = len;
724 
725         /* copy lvb to userspace if there is one, it's been updated, and
726            the user buffer has space for it */
727 
728         if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
729                 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
730                                  DLM_USER_LVB_LEN)) {
731                         error = -EFAULT;
732                         goto out;
733                 }
734 
735                 result.lvb_offset = len;
736                 len += DLM_USER_LVB_LEN;
737         }
738 
739         result.length = len;
740         resultptr = &result;
741 #ifdef CONFIG_COMPAT
742         if (compat) {
743                 compat_output(&result, &result32);
744                 resultptr = &result32;
745         }
746 #endif
747 
748         if (copy_to_user(buf, resultptr, struct_len))
749                 error = -EFAULT;
750         else
751                 error = len;
752  out:
753         return error;
754 }
755 
756 static int copy_version_to_user(char __user *buf, size_t count)
757 {
758         struct dlm_device_version ver;
759 
760         memset(&ver, 0, sizeof(struct dlm_device_version));
761         ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
762         ver.version[1] = DLM_DEVICE_VERSION_MINOR;
763         ver.version[2] = DLM_DEVICE_VERSION_PATCH;
764 
765         if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
766                 return -EFAULT;
767         return sizeof(struct dlm_device_version);
768 }
769 
770 /* a read returns a single ast described in a struct dlm_lock_result */
771 
772 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
773                            loff_t *ppos)
774 {
775         struct dlm_user_proc *proc = file->private_data;
776         struct dlm_lkb *lkb;
777         DECLARE_WAITQUEUE(wait, current);
778         struct dlm_callback cb;
779         int rv, resid, copy_lvb = 0;
780         int old_mode, new_mode;
781 
782         if (count == sizeof(struct dlm_device_version)) {
783                 rv = copy_version_to_user(buf, count);
784                 return rv;
785         }
786 
787         if (!proc) {
788                 log_print("non-version read from control device %zu", count);
789                 return -EINVAL;
790         }
791 
792 #ifdef CONFIG_COMPAT
793         if (count < sizeof(struct dlm_lock_result32))
794 #else
795         if (count < sizeof(struct dlm_lock_result))
796 #endif
797                 return -EINVAL;
798 
799  try_another:
800 
801         /* do we really need this? can a read happen after a close? */
802         if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
803                 return -EINVAL;
804 
805         spin_lock(&proc->asts_spin);
806         if (list_empty(&proc->asts)) {
807                 if (file->f_flags & O_NONBLOCK) {
808                         spin_unlock(&proc->asts_spin);
809                         return -EAGAIN;
810                 }
811 
812                 add_wait_queue(&proc->wait, &wait);
813 
814         repeat:
815                 set_current_state(TASK_INTERRUPTIBLE);
816                 if (list_empty(&proc->asts) && !signal_pending(current)) {
817                         spin_unlock(&proc->asts_spin);
818                         schedule();
819                         spin_lock(&proc->asts_spin);
820                         goto repeat;
821                 }
822                 set_current_state(TASK_RUNNING);
823                 remove_wait_queue(&proc->wait, &wait);
824 
825                 if (signal_pending(current)) {
826                         spin_unlock(&proc->asts_spin);
827                         return -ERESTARTSYS;
828                 }
829         }
830 
831         /* if we empty lkb_callbacks, we don't want to unlock the spinlock
832            without removing lkb_cb_list; so empty lkb_cb_list is always
833            consistent with empty lkb_callbacks */
834 
835         lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
836 
837         /* rem_lkb_callback sets a new lkb_last_cast */
838         old_mode = lkb->lkb_last_cast.mode;
839 
840         rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
841         if (rv < 0) {
842                 /* this shouldn't happen; lkb should have been removed from
843                    list when resid was zero */
844                 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
845                 list_del_init(&lkb->lkb_cb_list);
846                 spin_unlock(&proc->asts_spin);
847                 /* removes ref for proc->asts, may cause lkb to be freed */
848                 dlm_put_lkb(lkb);
849                 goto try_another;
850         }
851         if (!resid)
852                 list_del_init(&lkb->lkb_cb_list);
853         spin_unlock(&proc->asts_spin);
854 
855         if (cb.flags & DLM_CB_SKIP) {
856                 /* removes ref for proc->asts, may cause lkb to be freed */
857                 if (!resid)
858                         dlm_put_lkb(lkb);
859                 goto try_another;
860         }
861 
862         if (cb.flags & DLM_CB_CAST) {
863                 new_mode = cb.mode;
864 
865                 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
866                     dlm_lvb_operations[old_mode + 1][new_mode + 1])
867                         copy_lvb = 1;
868 
869                 lkb->lkb_lksb->sb_status = cb.sb_status;
870                 lkb->lkb_lksb->sb_flags = cb.sb_flags;
871         }
872 
873         rv = copy_result_to_user(lkb->lkb_ua,
874                                  test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
875                                  cb.flags, cb.mode, copy_lvb, buf, count);
876 
877         /* removes ref for proc->asts, may cause lkb to be freed */
878         if (!resid)
879                 dlm_put_lkb(lkb);
880 
881         return rv;
882 }
883 
884 static unsigned int device_poll(struct file *file, poll_table *wait)
885 {
886         struct dlm_user_proc *proc = file->private_data;
887 
888         poll_wait(file, &proc->wait, wait);
889 
890         spin_lock(&proc->asts_spin);
891         if (!list_empty(&proc->asts)) {
892                 spin_unlock(&proc->asts_spin);
893                 return POLLIN | POLLRDNORM;
894         }
895         spin_unlock(&proc->asts_spin);
896         return 0;
897 }
898 
899 int dlm_user_daemon_available(void)
900 {
901         /* dlm_controld hasn't started (or, has started, but not
902            properly populated configfs) */
903 
904         if (!dlm_our_nodeid())
905                 return 0;
906 
907         /* This is to deal with versions of dlm_controld that don't
908            know about the monitor device.  We assume that if the
909            dlm_controld was started (above), but the monitor device
910            was never opened, that it's an old version.  dlm_controld
911            should open the monitor device before populating configfs. */
912 
913         if (dlm_monitor_unused)
914                 return 1;
915 
916         return atomic_read(&dlm_monitor_opened) ? 1 : 0;
917 }
918 
919 static int ctl_device_open(struct inode *inode, struct file *file)
920 {
921         file->private_data = NULL;
922         return 0;
923 }
924 
925 static int ctl_device_close(struct inode *inode, struct file *file)
926 {
927         return 0;
928 }
929 
930 static int monitor_device_open(struct inode *inode, struct file *file)
931 {
932         atomic_inc(&dlm_monitor_opened);
933         dlm_monitor_unused = 0;
934         return 0;
935 }
936 
937 static int monitor_device_close(struct inode *inode, struct file *file)
938 {
939         if (atomic_dec_and_test(&dlm_monitor_opened))
940                 dlm_stop_lockspaces();
941         return 0;
942 }
943 
944 static const struct file_operations device_fops = {
945         .open    = device_open,
946         .release = device_close,
947         .read    = device_read,
948         .write   = device_write,
949         .poll    = device_poll,
950         .owner   = THIS_MODULE,
951         .llseek  = noop_llseek,
952 };
953 
954 static const struct file_operations ctl_device_fops = {
955         .open    = ctl_device_open,
956         .release = ctl_device_close,
957         .read    = device_read,
958         .write   = device_write,
959         .owner   = THIS_MODULE,
960         .llseek  = noop_llseek,
961 };
962 
963 static struct miscdevice ctl_device = {
964         .name  = "dlm-control",
965         .fops  = &ctl_device_fops,
966         .minor = MISC_DYNAMIC_MINOR,
967 };
968 
969 static const struct file_operations monitor_device_fops = {
970         .open    = monitor_device_open,
971         .release = monitor_device_close,
972         .owner   = THIS_MODULE,
973         .llseek  = noop_llseek,
974 };
975 
976 static struct miscdevice monitor_device = {
977         .name  = "dlm-monitor",
978         .fops  = &monitor_device_fops,
979         .minor = MISC_DYNAMIC_MINOR,
980 };
981 
982 int __init dlm_user_init(void)
983 {
984         int error;
985 
986         atomic_set(&dlm_monitor_opened, 0);
987 
988         error = misc_register(&ctl_device);
989         if (error) {
990                 log_print("misc_register failed for control device");
991                 goto out;
992         }
993 
994         error = misc_register(&monitor_device);
995         if (error) {
996                 log_print("misc_register failed for monitor device");
997                 misc_deregister(&ctl_device);
998         }
999  out:
1000         return error;
1001 }
1002 
1003 void dlm_user_exit(void)
1004 {
1005         misc_deregister(&ctl_device);
1006         misc_deregister(&monitor_device);
1007 }
1008 
1009 

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