fs/dlm/user.c

   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         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         int error;
 366
 367         /* The device is not registered.  This happens when the lockspace
 368            was never used from userspace, or when device_create_lockspace()
 369            calls dlm_release_lockspace() after the register fails. */
 370         if (!ls->ls_device.name)
 371                 return 0;
 372
 373         error = misc_deregister(&ls->ls_device);
 374         if (!error)
 375                 kfree(ls->ls_device.name);
 376         return error;
 377 }
 378
 379 static int device_user_purge(struct dlm_user_proc *proc,
 380                              struct dlm_purge_params *params)
 381 {
 382         struct dlm_ls *ls;
 383         int error;
 384
 385         ls = dlm_find_lockspace_local(proc->lockspace);
 386         if (!ls)
 387                 return -ENOENT;
 388
 389         error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
 390
 391         dlm_put_lockspace(ls);
 392         return error;
 393 }
 394
 395 static int device_create_lockspace(struct dlm_lspace_params *params)
 396 {
 397         dlm_lockspace_t *lockspace;
 398         struct dlm_ls *ls;
 399         int error;
 400
 401         if (!capable(CAP_SYS_ADMIN))
 402                 return -EPERM;
 403
 404         error = dlm_new_lockspace(params->name, NULL, params->flags,
 405                                   DLM_USER_LVB_LEN, NULL, NULL, NULL,
 406                                   &lockspace);
 407         if (error)
 408                 return error;
 409
 410         ls = dlm_find_lockspace_local(lockspace);
 411         if (!ls)
 412                 return -ENOENT;
 413
 414         error = dlm_device_register(ls, params->name);
 415         dlm_put_lockspace(ls);
 416
 417         if (error)
 418                 dlm_release_lockspace(lockspace, 0);
 419         else
 420                 error = ls->ls_device.minor;
 421
 422         return error;
 423 }
 424
 425 static int device_remove_lockspace(struct dlm_lspace_params *params)
 426 {
 427         dlm_lockspace_t *lockspace;
 428         struct dlm_ls *ls;
 429         int error, force = 0;
 430
 431         if (!capable(CAP_SYS_ADMIN))
 432                 return -EPERM;
 433
 434         ls = dlm_find_lockspace_device(params->minor);
 435         if (!ls)
 436                 return -ENOENT;
 437
 438         if (params->flags & DLM_USER_LSFLG_FORCEFREE)
 439                 force = 2;
 440
 441         lockspace = ls->ls_local_handle;
 442         dlm_put_lockspace(ls);
 443
 444         /* The final dlm_release_lockspace waits for references to go to
 445            zero, so all processes will need to close their device for the
 446            ls before the release will proceed.  release also calls the
 447            device_deregister above.  Converting a positive return value
 448            from release to zero means that userspace won't know when its
 449            release was the final one, but it shouldn't need to know. */
 450
 451         error = dlm_release_lockspace(lockspace, force);
 452         if (error > 0)
 453                 error = 0;
 454         return error;
 455 }
 456
 457 /* Check the user's version matches ours */
 458 static int check_version(struct dlm_write_request *req)
 459 {
 460         if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
 461             (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
 462              req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
 463
 464                 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
 465                        "user (%d.%d.%d) kernel (%d.%d.%d)\n",
 466                        current->comm,
 467                        task_pid_nr(current),
 468                        req->version[0],
 469                        req->version[1],
 470                        req->version[2],
 471                        DLM_DEVICE_VERSION_MAJOR,
 472                        DLM_DEVICE_VERSION_MINOR,
 473                        DLM_DEVICE_VERSION_PATCH);
 474                 return -EINVAL;
 475         }
 476         return 0;
 477 }
 478
 479 /*
 480  * device_write
 481  *
 482  *   device_user_lock
 483  *     dlm_user_request -> request_lock
 484  *     dlm_user_convert -> convert_lock
 485  *
 486  *   device_user_unlock
 487  *     dlm_user_unlock -> unlock_lock
 488  *     dlm_user_cancel -> cancel_lock
 489  *
 490  *   device_create_lockspace
 491  *     dlm_new_lockspace
 492  *
 493  *   device_remove_lockspace
 494  *     dlm_release_lockspace
 495  */
 496
 497 /* a write to a lockspace device is a lock or unlock request, a write
 498    to the control device is to create/remove a lockspace */
 499
 500 static ssize_t device_write(struct file *file, const char __user *buf,
 501                             size_t count, loff_t *ppos)
 502 {
 503         struct dlm_user_proc *proc = file->private_data;
 504         struct dlm_write_request *kbuf;
 505         int error;
 506
 507 #ifdef CONFIG_COMPAT
 508         if (count < sizeof(struct dlm_write_request32))
 509 #else
 510         if (count < sizeof(struct dlm_write_request))
 511 #endif
 512                 return -EINVAL;
 513
 514         /*
 515          * can't compare against COMPAT/dlm_write_request32 because
 516          * we don't yet know if is64bit is zero
 517          */
 518         if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
 519                 return -EINVAL;
 520
 521         kbuf = kzalloc(count + 1, GFP_NOFS);
 522         if (!kbuf)
 523                 return -ENOMEM;
 524
 525         if (copy_from_user(kbuf, buf, count)) {
 526                 error = -EFAULT;
 527                 goto out_free;
 528         }
 529
 530         if (check_version(kbuf)) {
 531                 error = -EBADE;
 532                 goto out_free;
 533         }
 534
 535 #ifdef CONFIG_COMPAT
 536         if (!kbuf->is64bit) {
 537                 struct dlm_write_request32 *k32buf;
 538                 int namelen = 0;
 539
 540                 if (count > sizeof(struct dlm_write_request32))
 541                         namelen = count - sizeof(struct dlm_write_request32);
 542
 543                 k32buf = (struct dlm_write_request32 *)kbuf;
 544
 545                 /* add 1 after namelen so that the name string is terminated */
 546                 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
 547                                GFP_NOFS);
 548                 if (!kbuf) {
 549                         kfree(k32buf);
 550                         return -ENOMEM;
 551                 }
 552
 553                 if (proc)
 554                         set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
 555
 556                 compat_input(kbuf, k32buf, namelen);
 557                 kfree(k32buf);
 558         }
 559 #endif
 560
 561         /* do we really need this? can a write happen after a close? */
 562         if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
 563             (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
 564                 error = -EINVAL;
 565                 goto out_free;
 566         }
 567
 568         error = -EINVAL;
 569
 570         switch (kbuf->cmd)
 571         {
 572         case DLM_USER_LOCK:
 573                 if (!proc) {
 574                         log_print("no locking on control device");
 575                         goto out_free;
 576                 }
 577                 error = device_user_lock(proc, &kbuf->i.lock);
 578                 break;
 579
 580         case DLM_USER_UNLOCK:
 581                 if (!proc) {
 582                         log_print("no locking on control device");
 583                         goto out_free;
 584                 }
 585                 error = device_user_unlock(proc, &kbuf->i.lock);
 586                 break;
 587
 588         case DLM_USER_DEADLOCK:
 589                 if (!proc) {
 590                         log_print("no locking on control device");
 591                         goto out_free;
 592                 }
 593                 error = device_user_deadlock(proc, &kbuf->i.lock);
 594                 break;
 595
 596         case DLM_USER_CREATE_LOCKSPACE:
 597                 if (proc) {
 598                         log_print("create/remove only on control device");
 599                         goto out_free;
 600                 }
 601                 error = device_create_lockspace(&kbuf->i.lspace);
 602                 break;
 603
 604         case DLM_USER_REMOVE_LOCKSPACE:
 605                 if (proc) {
 606                         log_print("create/remove only on control device");
 607                         goto out_free;
 608                 }
 609                 error = device_remove_lockspace(&kbuf->i.lspace);
 610                 break;
 611
 612         case DLM_USER_PURGE:
 613                 if (!proc) {
 614                         log_print("no locking on control device");
 615                         goto out_free;
 616                 }
 617                 error = device_user_purge(proc, &kbuf->i.purge);
 618                 break;
 619
 620         default:
 621                 log_print("Unknown command passed to DLM device : %d\n",
 622                           kbuf->cmd);
 623         }
 624
 625  out_free:
 626         kfree(kbuf);
 627         return error;
 628 }
 629
 630 /* Every process that opens the lockspace device has its own "proc" structure
 631    hanging off the open file that's used to keep track of locks owned by the
 632    process and asts that need to be delivered to the process. */
 633
 634 static int device_open(struct inode *inode, struct file *file)
 635 {
 636         struct dlm_user_proc *proc;
 637         struct dlm_ls *ls;
 638
 639         ls = dlm_find_lockspace_device(iminor(inode));
 640         if (!ls)
 641                 return -ENOENT;
 642
 643         proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
 644         if (!proc) {
 645                 dlm_put_lockspace(ls);
 646                 return -ENOMEM;
 647         }
 648
 649         proc->lockspace = ls->ls_local_handle;
 650         INIT_LIST_HEAD(&proc->asts);
 651         INIT_LIST_HEAD(&proc->locks);
 652         INIT_LIST_HEAD(&proc->unlocking);
 653         spin_lock_init(&proc->asts_spin);
 654         spin_lock_init(&proc->locks_spin);
 655         init_waitqueue_head(&proc->wait);
 656         file->private_data = proc;
 657
 658         return 0;
 659 }
 660
 661 static int device_close(struct inode *inode, struct file *file)
 662 {
 663         struct dlm_user_proc *proc = file->private_data;
 664         struct dlm_ls *ls;
 665
 666         ls = dlm_find_lockspace_local(proc->lockspace);
 667         if (!ls)
 668                 return -ENOENT;
 669
 670         set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
 671
 672         dlm_clear_proc_locks(ls, proc);
 673
 674         /* at this point no more lkb's should exist for this lockspace,
 675            so there's no chance of dlm_user_add_ast() being called and
 676            looking for lkb->ua->proc */
 677
 678         kfree(proc);
 679         file->private_data = NULL;
 680
 681         dlm_put_lockspace(ls);
 682         dlm_put_lockspace(ls);  /* for the find in device_open() */
 683
 684         /* FIXME: AUTOFREE: if this ls is no longer used do
 685            device_remove_lockspace() */
 686
 687         return 0;
 688 }
 689
 690 static int copy_result_to_user(struct dlm_user_args *ua, int compat,
 691                                uint32_t flags, int mode, int copy_lvb,
 692                                char __user *buf, size_t count)
 693 {
 694 #ifdef CONFIG_COMPAT
 695         struct dlm_lock_result32 result32;
 696 #endif
 697         struct dlm_lock_result result;
 698         void *resultptr;
 699         int error=0;
 700         int len;
 701         int struct_len;
 702
 703         memset(&result, 0, sizeof(struct dlm_lock_result));
 704         result.version[0] = DLM_DEVICE_VERSION_MAJOR;
 705         result.version[1] = DLM_DEVICE_VERSION_MINOR;
 706         result.version[2] = DLM_DEVICE_VERSION_PATCH;
 707         memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
 708         result.user_lksb = ua->user_lksb;
 709
 710         /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
 711            in a conversion unless the conversion is successful.  See code
 712            in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
 713            notes that a new blocking AST address and parameter are set even if
 714            the conversion fails, so maybe we should just do that. */
 715
 716         if (flags & DLM_CB_BAST) {
 717                 result.user_astaddr = ua->bastaddr;
 718                 result.user_astparam = ua->bastparam;
 719                 result.bast_mode = mode;
 720         } else {
 721                 result.user_astaddr = ua->castaddr;
 722                 result.user_astparam = ua->castparam;
 723         }
 724
 725 #ifdef CONFIG_COMPAT
 726         if (compat)
 727                 len = sizeof(struct dlm_lock_result32);
 728         else
 729 #endif
 730                 len = sizeof(struct dlm_lock_result);
 731         struct_len = len;
 732
 733         /* copy lvb to userspace if there is one, it's been updated, and
 734            the user buffer has space for it */
 735
 736         if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
 737                 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
 738                                  DLM_USER_LVB_LEN)) {
 739                         error = -EFAULT;
 740                         goto out;
 741                 }
 742
 743                 result.lvb_offset = len;
 744                 len += DLM_USER_LVB_LEN;
 745         }
 746
 747         result.length = len;
 748         resultptr = &result;
 749 #ifdef CONFIG_COMPAT
 750         if (compat) {
 751                 compat_output(&result, &result32);
 752                 resultptr = &result32;
 753         }
 754 #endif
 755
 756         if (copy_to_user(buf, resultptr, struct_len))
 757                 error = -EFAULT;
 758         else
 759                 error = len;
 760  out:
 761         return error;
 762 }
 763
 764 static int copy_version_to_user(char __user *buf, size_t count)
 765 {
 766         struct dlm_device_version ver;
 767
 768         memset(&ver, 0, sizeof(struct dlm_device_version));
 769         ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
 770         ver.version[1] = DLM_DEVICE_VERSION_MINOR;
 771         ver.version[2] = DLM_DEVICE_VERSION_PATCH;
 772
 773         if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
 774                 return -EFAULT;
 775         return sizeof(struct dlm_device_version);
 776 }
 777
 778 /* a read returns a single ast described in a struct dlm_lock_result */
 779
 780 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 781                            loff_t *ppos)
 782 {
 783         struct dlm_user_proc *proc = file->private_data;
 784         struct dlm_lkb *lkb;
 785         DECLARE_WAITQUEUE(wait, current);
 786         struct dlm_callback cb;
 787         int rv, resid, copy_lvb = 0;
 788
 789         if (count == sizeof(struct dlm_device_version)) {
 790                 rv = copy_version_to_user(buf, count);
 791                 return rv;
 792         }
 793
 794         if (!proc) {
 795                 log_print("non-version read from control device %zu", count);
 796                 return -EINVAL;
 797         }
 798
 799 #ifdef CONFIG_COMPAT
 800         if (count < sizeof(struct dlm_lock_result32))
 801 #else
 802         if (count < sizeof(struct dlm_lock_result))
 803 #endif
 804                 return -EINVAL;
 805
 806  try_another:
 807
 808         /* do we really need this? can a read happen after a close? */
 809         if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
 810                 return -EINVAL;
 811
 812         spin_lock(&proc->asts_spin);
 813         if (list_empty(&proc->asts)) {
 814                 if (file->f_flags & O_NONBLOCK) {
 815                         spin_unlock(&proc->asts_spin);
 816                         return -EAGAIN;
 817                 }
 818
 819                 add_wait_queue(&proc->wait, &wait);
 820
 821         repeat:
 822                 set_current_state(TASK_INTERRUPTIBLE);
 823                 if (list_empty(&proc->asts) && !signal_pending(current)) {
 824                         spin_unlock(&proc->asts_spin);
 825                         schedule();
 826                         spin_lock(&proc->asts_spin);
 827                         goto repeat;
 828                 }
 829                 set_current_state(TASK_RUNNING);
 830                 remove_wait_queue(&proc->wait, &wait);
 831
 832                 if (signal_pending(current)) {
 833                         spin_unlock(&proc->asts_spin);
 834                         return -ERESTARTSYS;
 835                 }
 836         }
 837
 838         /* if we empty lkb_callbacks, we don't want to unlock the spinlock
 839            without removing lkb_cb_list; so empty lkb_cb_list is always
 840            consistent with empty lkb_callbacks */
 841
 842         lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
 843
 844         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                 int old_mode, new_mode;
 868
 869                 old_mode = lkb->lkb_last_cast.mode;
 870                 new_mode = cb.mode;
 871
 872                 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
 873                     dlm_lvb_operations[old_mode + 1][new_mode + 1])
 874                         copy_lvb = 1;
 875
 876                 lkb->lkb_lksb->sb_status = cb.sb_status;
 877                 lkb->lkb_lksb->sb_flags = cb.sb_flags;
 878         }
 879
 880         rv = copy_result_to_user(lkb->lkb_ua,
 881                                  test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
 882                                  cb.flags, cb.mode, copy_lvb, buf, count);
 883
 884         /* removes ref for proc->asts, may cause lkb to be freed */
 885         if (!resid)
 886                 dlm_put_lkb(lkb);
 887
 888         return rv;
 889 }
 890
 891 static unsigned int device_poll(struct file *file, poll_table *wait)
 892 {
 893         struct dlm_user_proc *proc = file->private_data;
 894
 895         poll_wait(file, &proc->wait, wait);
 896
 897         spin_lock(&proc->asts_spin);
 898         if (!list_empty(&proc->asts)) {
 899                 spin_unlock(&proc->asts_spin);
 900                 return POLLIN | POLLRDNORM;
 901         }
 902         spin_unlock(&proc->asts_spin);
 903         return 0;
 904 }
 905
 906 int dlm_user_daemon_available(void)
 907 {
 908         /* dlm_controld hasn't started (or, has started, but not
 909            properly populated configfs) */
 910
 911         if (!dlm_our_nodeid())
 912                 return 0;
 913
 914         /* This is to deal with versions of dlm_controld that don't
 915            know about the monitor device.  We assume that if the
 916            dlm_controld was started (above), but the monitor device
 917            was never opened, that it's an old version.  dlm_controld
 918            should open the monitor device before populating configfs. */
 919
 920         if (dlm_monitor_unused)
 921                 return 1;
 922
 923         return atomic_read(&dlm_monitor_opened) ? 1 : 0;
 924 }
 925
 926 static int ctl_device_open(struct inode *inode, struct file *file)
 927 {
 928         file->private_data = NULL;
 929         return 0;
 930 }
 931
 932 static int ctl_device_close(struct inode *inode, struct file *file)
 933 {
 934         return 0;
 935 }
 936
 937 static int monitor_device_open(struct inode *inode, struct file *file)
 938 {
 939         atomic_inc(&dlm_monitor_opened);
 940         dlm_monitor_unused = 0;
 941         return 0;
 942 }
 943
 944 static int monitor_device_close(struct inode *inode, struct file *file)
 945 {
 946         if (atomic_dec_and_test(&dlm_monitor_opened))
 947                 dlm_stop_lockspaces();
 948         return 0;
 949 }
 950
 951 static const struct file_operations device_fops = {
 952         .open    = device_open,
 953         .release = device_close,
 954         .read    = device_read,
 955         .write   = device_write,
 956         .poll    = device_poll,
 957         .owner   = THIS_MODULE,
 958         .llseek  = noop_llseek,
 959 };
 960
 961 static const struct file_operations ctl_device_fops = {
 962         .open    = ctl_device_open,
 963         .release = ctl_device_close,
 964         .read    = device_read,
 965         .write   = device_write,
 966         .owner   = THIS_MODULE,
 967         .llseek  = noop_llseek,
 968 };
 969
 970 static struct miscdevice ctl_device = {
 971         .name  = "dlm-control",
 972         .fops  = &ctl_device_fops,
 973         .minor = MISC_DYNAMIC_MINOR,
 974 };
 975
 976 static const struct file_operations monitor_device_fops = {
 977         .open    = monitor_device_open,
 978         .release = monitor_device_close,
 979         .owner   = THIS_MODULE,
 980         .llseek  = noop_llseek,
 981 };
 982
 983 static struct miscdevice monitor_device = {
 984         .name  = "dlm-monitor",
 985         .fops  = &monitor_device_fops,
 986         .minor = MISC_DYNAMIC_MINOR,
 987 };
 988
 989 int __init dlm_user_init(void)
 990 {
 991         int error;
 992
 993         atomic_set(&dlm_monitor_opened, 0);
 994
 995         error = misc_register(&ctl_device);
 996         if (error) {
 997                 log_print("misc_register failed for control device");
 998                 goto out;
 999         }
1000
1001         error = misc_register(&monitor_device);
1002         if (error) {
1003                 log_print("misc_register failed for monitor device");
1004                 misc_deregister(&ctl_device);
1005         }
1006  out:
1007         return error;
1008 }
1009
1010 void dlm_user_exit(void)
1011 {
1012         misc_deregister(&ctl_device);
1013         misc_deregister(&monitor_device);
1014 }
1015