fs/dlm/user.c

   1 /*
   2  * Copyright (C) 2006-2007 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
  21 #include "dlm_internal.h"
  22 #include "lockspace.h"
  23 #include "lock.h"
  24 #include "lvb_table.h"
  25 #include "user.h"
  26
  27 static const char name_prefix[] = "dlm";
  28 static const struct file_operations device_fops;
  29
  30 #ifdef CONFIG_COMPAT
  31
  32 struct dlm_lock_params32 {
  33         __u8 mode;
  34         __u8 namelen;
  35         __u16 unused;
  36         __u32 flags;
  37         __u32 lkid;
  38         __u32 parent;
  39         __u64 xid;
  40         __u64 timeout;
  41         __u32 castparam;
  42         __u32 castaddr;
  43         __u32 bastparam;
  44         __u32 bastaddr;
  45         __u32 lksb;
  46         char lvb[DLM_USER_LVB_LEN];
  47         char name[0];
  48 };
  49
  50 struct dlm_write_request32 {
  51         __u32 version[3];
  52         __u8 cmd;
  53         __u8 is64bit;
  54         __u8 unused[2];
  55
  56         union  {
  57                 struct dlm_lock_params32 lock;
  58                 struct dlm_lspace_params lspace;
  59                 struct dlm_purge_params purge;
  60         } i;
  61 };
  62
  63 struct dlm_lksb32 {
  64         __u32 sb_status;
  65         __u32 sb_lkid;
  66         __u8 sb_flags;
  67         __u32 sb_lvbptr;
  68 };
  69
  70 struct dlm_lock_result32 {
  71         __u32 version[3];
  72         __u32 length;
  73         __u32 user_astaddr;
  74         __u32 user_astparam;
  75         __u32 user_lksb;
  76         struct dlm_lksb32 lksb;
  77         __u8 bast_mode;
  78         __u8 unused[3];
  79         /* Offsets may be zero if no data is present */
  80         __u32 lvb_offset;
  81 };
  82
  83 static void compat_input(struct dlm_write_request *kb,
  84                          struct dlm_write_request32 *kb32,
  85                          int max_namelen)
  86 {
  87         kb->version[0] = kb32->version[0];
  88         kb->version[1] = kb32->version[1];
  89         kb->version[2] = kb32->version[2];
  90
  91         kb->cmd = kb32->cmd;
  92         kb->is64bit = kb32->is64bit;
  93         if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
  94             kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
  95                 kb->i.lspace.flags = kb32->i.lspace.flags;
  96                 kb->i.lspace.minor = kb32->i.lspace.minor;
  97                 strcpy(kb->i.lspace.name, kb32->i.lspace.name);
  98         } else if (kb->cmd == DLM_USER_PURGE) {
  99                 kb->i.purge.nodeid = kb32->i.purge.nodeid;
 100                 kb->i.purge.pid = kb32->i.purge.pid;
 101         } else {
 102                 kb->i.lock.mode = kb32->i.lock.mode;
 103                 kb->i.lock.namelen = kb32->i.lock.namelen;
 104                 kb->i.lock.flags = kb32->i.lock.flags;
 105                 kb->i.lock.lkid = kb32->i.lock.lkid;
 106                 kb->i.lock.parent = kb32->i.lock.parent;
 107                 kb->i.lock.xid = kb32->i.lock.xid;
 108                 kb->i.lock.timeout = kb32->i.lock.timeout;
 109                 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
 110                 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
 111                 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
 112                 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
 113                 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
 114                 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
 115                 if (kb->i.lock.namelen <= max_namelen)
 116                         memcpy(kb->i.lock.name, kb32->i.lock.name,
 117                                kb->i.lock.namelen);
 118                 else
 119                         kb->i.lock.namelen = max_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(struct dlm_lkb *lkb, int sb_status, int type)
 157 {
 158         switch (sb_status) {
 159         case -DLM_EUNLOCK:
 160                 return 1;
 161         case -DLM_ECANCEL:
 162         case -ETIMEDOUT:
 163         case -EDEADLK:
 164                 if (lkb->lkb_grmode == DLM_LOCK_IV)
 165                         return 1;
 166                 break;
 167         case -EAGAIN:
 168                 if (type == AST_COMP && lkb->lkb_grmode == DLM_LOCK_IV)
 169                         return 1;
 170                 break;
 171         }
 172         return 0;
 173 }
 174
 175 /* we could possibly check if the cancel of an orphan has resulted in the lkb
 176    being removed and then remove that lkb from the orphans list and free it */
 177
 178 void dlm_user_add_ast(struct dlm_lkb *lkb, int type)
 179 {
 180         struct dlm_ls *ls;
 181         struct dlm_user_args *ua;
 182         struct dlm_user_proc *proc;
 183         int eol = 0, ast_type;
 184
 185         if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
 186                 return;
 187
 188         ls = lkb->lkb_resource->res_ls;
 189         mutex_lock(&ls->ls_clear_proc_locks);
 190
 191         /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
 192            can't be delivered.  For ORPHAN's, dlm_clear_proc_locks() freed
 193            lkb->ua so we can't try to use it.  This second check is necessary
 194            for cases where a completion ast is received for an operation that
 195            began before clear_proc_locks did its cancel/unlock. */
 196
 197         if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
 198                 goto out;
 199
 200         DLM_ASSERT(lkb->lkb_astparam, dlm_print_lkb(lkb););
 201         ua = (struct dlm_user_args *)lkb->lkb_astparam;
 202         proc = ua->proc;
 203
 204         if (type == AST_BAST && ua->bastaddr == NULL)
 205                 goto out;
 206
 207         spin_lock(&proc->asts_spin);
 208
 209         ast_type = lkb->lkb_ast_type;
 210         lkb->lkb_ast_type |= type;
 211
 212         if (!ast_type) {
 213                 kref_get(&lkb->lkb_ref);
 214                 list_add_tail(&lkb->lkb_astqueue, &proc->asts);
 215                 wake_up_interruptible(&proc->wait);
 216         }
 217         if (type == AST_COMP && (ast_type & AST_COMP))
 218                 log_debug(ls, "ast overlap %x status %x %x",
 219                           lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags);
 220
 221         eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type);
 222         if (eol) {
 223                 lkb->lkb_ast_type &= ~AST_BAST;
 224                 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
 225         }
 226
 227         /* We want to copy the lvb to userspace when the completion
 228            ast is read if the status is 0, the lock has an lvb and
 229            lvb_ops says we should.  We could probably have set_lvb_lock()
 230            set update_user_lvb instead and not need old_mode */
 231
 232         if ((lkb->lkb_ast_type & AST_COMP) &&
 233             (lkb->lkb_lksb->sb_status == 0) &&
 234             lkb->lkb_lksb->sb_lvbptr &&
 235             dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1])
 236                 ua->update_user_lvb = 1;
 237         else
 238                 ua->update_user_lvb = 0;
 239
 240         spin_unlock(&proc->asts_spin);
 241
 242         if (eol) {
 243                 spin_lock(&proc->locks_spin);
 244                 if (!list_empty(&lkb->lkb_ownqueue)) {
 245                         list_del_init(&lkb->lkb_ownqueue);
 246                         dlm_put_lkb(lkb);
 247                 }
 248                 spin_unlock(&proc->locks_spin);
 249         }
 250  out:
 251         mutex_unlock(&ls->ls_clear_proc_locks);
 252 }
 253
 254 static int device_user_lock(struct dlm_user_proc *proc,
 255                             struct dlm_lock_params *params)
 256 {
 257         struct dlm_ls *ls;
 258         struct dlm_user_args *ua;
 259         int error = -ENOMEM;
 260
 261         ls = dlm_find_lockspace_local(proc->lockspace);
 262         if (!ls)
 263                 return -ENOENT;
 264
 265         if (!params->castaddr || !params->lksb) {
 266                 error = -EINVAL;
 267                 goto out;
 268         }
 269
 270         ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
 271         if (!ua)
 272                 goto out;
 273         ua->proc = proc;
 274         ua->user_lksb = params->lksb;
 275         ua->castparam = params->castparam;
 276         ua->castaddr = params->castaddr;
 277         ua->bastparam = params->bastparam;
 278         ua->bastaddr = params->bastaddr;
 279         ua->xid = params->xid;
 280
 281         if (params->flags & DLM_LKF_CONVERT)
 282                 error = dlm_user_convert(ls, ua,
 283                                          params->mode, params->flags,
 284                                          params->lkid, params->lvb,
 285                                          (unsigned long) params->timeout);
 286         else {
 287                 error = dlm_user_request(ls, ua,
 288                                          params->mode, params->flags,
 289                                          params->name, params->namelen,
 290                                          (unsigned long) params->timeout);
 291                 if (!error)
 292                         error = ua->lksb.sb_lkid;
 293         }
 294  out:
 295         dlm_put_lockspace(ls);
 296         return error;
 297 }
 298
 299 static int device_user_unlock(struct dlm_user_proc *proc,
 300                               struct dlm_lock_params *params)
 301 {
 302         struct dlm_ls *ls;
 303         struct dlm_user_args *ua;
 304         int error = -ENOMEM;
 305
 306         ls = dlm_find_lockspace_local(proc->lockspace);
 307         if (!ls)
 308                 return -ENOENT;
 309
 310         ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
 311         if (!ua)
 312                 goto out;
 313         ua->proc = proc;
 314         ua->user_lksb = params->lksb;
 315         ua->castparam = params->castparam;
 316         ua->castaddr = params->castaddr;
 317
 318         if (params->flags & DLM_LKF_CANCEL)
 319                 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
 320         else
 321                 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
 322                                         params->lvb);
 323  out:
 324         dlm_put_lockspace(ls);
 325         return error;
 326 }
 327
 328 static int device_user_deadlock(struct dlm_user_proc *proc,
 329                                 struct dlm_lock_params *params)
 330 {
 331         struct dlm_ls *ls;
 332         int error;
 333
 334         ls = dlm_find_lockspace_local(proc->lockspace);
 335         if (!ls)
 336                 return -ENOENT;
 337
 338         error = dlm_user_deadlock(ls, params->flags, params->lkid);
 339
 340         dlm_put_lockspace(ls);
 341         return error;
 342 }
 343
 344 static int create_misc_device(struct dlm_ls *ls, char *name)
 345 {
 346         int error, len;
 347
 348         error = -ENOMEM;
 349         len = strlen(name) + strlen(name_prefix) + 2;
 350         ls->ls_device.name = kzalloc(len, GFP_KERNEL);
 351         if (!ls->ls_device.name)
 352                 goto fail;
 353
 354         snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
 355                  name);
 356         ls->ls_device.fops = &device_fops;
 357         ls->ls_device.minor = MISC_DYNAMIC_MINOR;
 358
 359         error = misc_register(&ls->ls_device);
 360         if (error) {
 361                 kfree(ls->ls_device.name);
 362         }
 363 fail:
 364         return error;
 365 }
 366
 367 static int device_user_purge(struct dlm_user_proc *proc,
 368                              struct dlm_purge_params *params)
 369 {
 370         struct dlm_ls *ls;
 371         int error;
 372
 373         ls = dlm_find_lockspace_local(proc->lockspace);
 374         if (!ls)
 375                 return -ENOENT;
 376
 377         error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
 378
 379         dlm_put_lockspace(ls);
 380         return error;
 381 }
 382
 383 static int device_create_lockspace(struct dlm_lspace_params *params)
 384 {
 385         dlm_lockspace_t *lockspace;
 386         struct dlm_ls *ls;
 387         int error;
 388
 389         if (!capable(CAP_SYS_ADMIN))
 390                 return -EPERM;
 391
 392         error = dlm_new_lockspace(params->name, strlen(params->name),
 393                                   &lockspace, params->flags, DLM_USER_LVB_LEN);
 394         if (error)
 395                 return error;
 396
 397         ls = dlm_find_lockspace_local(lockspace);
 398         if (!ls)
 399                 return -ENOENT;
 400
 401         error = create_misc_device(ls, params->name);
 402         dlm_put_lockspace(ls);
 403
 404         if (error)
 405                 dlm_release_lockspace(lockspace, 0);
 406         else
 407                 error = ls->ls_device.minor;
 408
 409         return error;
 410 }
 411
 412 static int device_remove_lockspace(struct dlm_lspace_params *params)
 413 {
 414         dlm_lockspace_t *lockspace;
 415         struct dlm_ls *ls;
 416         int error, force = 0;
 417
 418         if (!capable(CAP_SYS_ADMIN))
 419                 return -EPERM;
 420
 421         ls = dlm_find_lockspace_device(params->minor);
 422         if (!ls)
 423                 return -ENOENT;
 424
 425         /* Deregister the misc device first, so we don't have
 426          * a device that's not attached to a lockspace. If
 427          * dlm_release_lockspace fails then we can recreate it
 428          */
 429         error = misc_deregister(&ls->ls_device);
 430         if (error) {
 431                 dlm_put_lockspace(ls);
 432                 goto out;
 433         }
 434         kfree(ls->ls_device.name);
 435
 436         if (params->flags & DLM_USER_LSFLG_FORCEFREE)
 437                 force = 2;
 438
 439         lockspace = ls->ls_local_handle;
 440
 441         /* dlm_release_lockspace waits for references to go to zero,
 442            so all processes will need to close their device for the ls
 443            before the release will procede */
 444
 445         dlm_put_lockspace(ls);
 446         error = dlm_release_lockspace(lockspace, force);
 447         if (error)
 448                 create_misc_device(ls, ls->ls_name);
 449  out:
 450         return error;
 451 }
 452
 453 /* Check the user's version matches ours */
 454 static int check_version(struct dlm_write_request *req)
 455 {
 456         if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
 457             (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
 458              req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
 459
 460                 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
 461                        "user (%d.%d.%d) kernel (%d.%d.%d)\n",
 462                        current->comm,
 463                        task_pid_nr(current),
 464                        req->version[0],
 465                        req->version[1],
 466                        req->version[2],
 467                        DLM_DEVICE_VERSION_MAJOR,
 468                        DLM_DEVICE_VERSION_MINOR,
 469                        DLM_DEVICE_VERSION_PATCH);
 470                 return -EINVAL;
 471         }
 472         return 0;
 473 }
 474
 475 /*
 476  * device_write
 477  *
 478  *   device_user_lock
 479  *     dlm_user_request -> request_lock
 480  *     dlm_user_convert -> convert_lock
 481  *
 482  *   device_user_unlock
 483  *     dlm_user_unlock -> unlock_lock
 484  *     dlm_user_cancel -> cancel_lock
 485  *
 486  *   device_create_lockspace
 487  *     dlm_new_lockspace
 488  *
 489  *   device_remove_lockspace
 490  *     dlm_release_lockspace
 491  */
 492
 493 /* a write to a lockspace device is a lock or unlock request, a write
 494    to the control device is to create/remove a lockspace */
 495
 496 static ssize_t device_write(struct file *file, const char __user *buf,
 497                             size_t count, loff_t *ppos)
 498 {
 499         struct dlm_user_proc *proc = file->private_data;
 500         struct dlm_write_request *kbuf;
 501         sigset_t tmpsig, allsigs;
 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         kbuf = kmalloc(count, GFP_KERNEL);
 512         if (!kbuf)
 513                 return -ENOMEM;
 514
 515         if (copy_from_user(kbuf, buf, count)) {
 516                 error = -EFAULT;
 517                 goto out_free;
 518         }
 519
 520         if (check_version(kbuf)) {
 521                 error = -EBADE;
 522                 goto out_free;
 523         }
 524
 525 #ifdef CONFIG_COMPAT
 526         if (!kbuf->is64bit) {
 527                 struct dlm_write_request32 *k32buf;
 528                 k32buf = (struct dlm_write_request32 *)kbuf;
 529                 kbuf = kmalloc(count + (sizeof(struct dlm_write_request) -
 530                                sizeof(struct dlm_write_request32)), GFP_KERNEL);
 531                 if (!kbuf)
 532                         return -ENOMEM;
 533
 534                 if (proc)
 535                         set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
 536                 compat_input(kbuf, k32buf,
 537                              count - sizeof(struct dlm_write_request32));
 538                 kfree(k32buf);
 539         }
 540 #endif
 541
 542         /* do we really need this? can a write happen after a close? */
 543         if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
 544             test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
 545                 return -EINVAL;
 546
 547         sigfillset(&allsigs);
 548         sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
 549
 550         error = -EINVAL;
 551
 552         switch (kbuf->cmd)
 553         {
 554         case DLM_USER_LOCK:
 555                 if (!proc) {
 556                         log_print("no locking on control device");
 557                         goto out_sig;
 558                 }
 559                 error = device_user_lock(proc, &kbuf->i.lock);
 560                 break;
 561
 562         case DLM_USER_UNLOCK:
 563                 if (!proc) {
 564                         log_print("no locking on control device");
 565                         goto out_sig;
 566                 }
 567                 error = device_user_unlock(proc, &kbuf->i.lock);
 568                 break;
 569
 570         case DLM_USER_DEADLOCK:
 571                 if (!proc) {
 572                         log_print("no locking on control device");
 573                         goto out_sig;
 574                 }
 575                 error = device_user_deadlock(proc, &kbuf->i.lock);
 576                 break;
 577
 578         case DLM_USER_CREATE_LOCKSPACE:
 579                 if (proc) {
 580                         log_print("create/remove only on control device");
 581                         goto out_sig;
 582                 }
 583                 error = device_create_lockspace(&kbuf->i.lspace);
 584                 break;
 585
 586         case DLM_USER_REMOVE_LOCKSPACE:
 587                 if (proc) {
 588                         log_print("create/remove only on control device");
 589                         goto out_sig;
 590                 }
 591                 error = device_remove_lockspace(&kbuf->i.lspace);
 592                 break;
 593
 594         case DLM_USER_PURGE:
 595                 if (!proc) {
 596                         log_print("no locking on control device");
 597                         goto out_sig;
 598                 }
 599                 error = device_user_purge(proc, &kbuf->i.purge);
 600                 break;
 601
 602         default:
 603                 log_print("Unknown command passed to DLM device : %d\n",
 604                           kbuf->cmd);
 605         }
 606
 607  out_sig:
 608         sigprocmask(SIG_SETMASK, &tmpsig, NULL);
 609         recalc_sigpending();
 610  out_free:
 611         kfree(kbuf);
 612         return error;
 613 }
 614
 615 /* Every process that opens the lockspace device has its own "proc" structure
 616    hanging off the open file that's used to keep track of locks owned by the
 617    process and asts that need to be delivered to the process. */
 618
 619 static int device_open(struct inode *inode, struct file *file)
 620 {
 621         struct dlm_user_proc *proc;
 622         struct dlm_ls *ls;
 623
 624         ls = dlm_find_lockspace_device(iminor(inode));
 625         if (!ls)
 626                 return -ENOENT;
 627
 628         proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
 629         if (!proc) {
 630                 dlm_put_lockspace(ls);
 631                 return -ENOMEM;
 632         }
 633
 634         proc->lockspace = ls->ls_local_handle;
 635         INIT_LIST_HEAD(&proc->asts);
 636         INIT_LIST_HEAD(&proc->locks);
 637         INIT_LIST_HEAD(&proc->unlocking);
 638         spin_lock_init(&proc->asts_spin);
 639         spin_lock_init(&proc->locks_spin);
 640         init_waitqueue_head(&proc->wait);
 641         file->private_data = proc;
 642
 643         return 0;
 644 }
 645
 646 static int device_close(struct inode *inode, struct file *file)
 647 {
 648         struct dlm_user_proc *proc = file->private_data;
 649         struct dlm_ls *ls;
 650         sigset_t tmpsig, allsigs;
 651
 652         ls = dlm_find_lockspace_local(proc->lockspace);
 653         if (!ls)
 654                 return -ENOENT;
 655
 656         sigfillset(&allsigs);
 657         sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
 658
 659         set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
 660
 661         dlm_clear_proc_locks(ls, proc);
 662
 663         /* at this point no more lkb's should exist for this lockspace,
 664            so there's no chance of dlm_user_add_ast() being called and
 665            looking for lkb->ua->proc */
 666
 667         kfree(proc);
 668         file->private_data = NULL;
 669
 670         dlm_put_lockspace(ls);
 671         dlm_put_lockspace(ls);  /* for the find in device_open() */
 672
 673         /* FIXME: AUTOFREE: if this ls is no longer used do
 674            device_remove_lockspace() */
 675
 676         sigprocmask(SIG_SETMASK, &tmpsig, NULL);
 677         recalc_sigpending();
 678
 679         return 0;
 680 }
 681
 682 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type,
 683                                int bmode, char __user *buf, size_t count)
 684 {
 685 #ifdef CONFIG_COMPAT
 686         struct dlm_lock_result32 result32;
 687 #endif
 688         struct dlm_lock_result result;
 689         void *resultptr;
 690         int error=0;
 691         int len;
 692         int struct_len;
 693
 694         memset(&result, 0, sizeof(struct dlm_lock_result));
 695         result.version[0] = DLM_DEVICE_VERSION_MAJOR;
 696         result.version[1] = DLM_DEVICE_VERSION_MINOR;
 697         result.version[2] = DLM_DEVICE_VERSION_PATCH;
 698         memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
 699         result.user_lksb = ua->user_lksb;
 700
 701         /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
 702            in a conversion unless the conversion is successful.  See code
 703            in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
 704            notes that a new blocking AST address and parameter are set even if
 705            the conversion fails, so maybe we should just do that. */
 706
 707         if (type == AST_BAST) {
 708                 result.user_astaddr = ua->bastaddr;
 709                 result.user_astparam = ua->bastparam;
 710                 result.bast_mode = bmode;
 711         } else {
 712                 result.user_astaddr = ua->castaddr;
 713                 result.user_astparam = ua->castparam;
 714         }
 715
 716 #ifdef CONFIG_COMPAT
 717         if (compat)
 718                 len = sizeof(struct dlm_lock_result32);
 719         else
 720 #endif
 721                 len = sizeof(struct dlm_lock_result);
 722         struct_len = len;
 723
 724         /* copy lvb to userspace if there is one, it's been updated, and
 725            the user buffer has space for it */
 726
 727         if (ua->update_user_lvb && ua->lksb.sb_lvbptr &&
 728             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         struct dlm_user_args *ua;
 778         DECLARE_WAITQUEUE(wait, current);
 779         int error, type=0, bmode=0, removed = 0;
 780
 781         if (count == sizeof(struct dlm_device_version)) {
 782                 error = copy_version_to_user(buf, count);
 783                 return error;
 784         }
 785
 786         if (!proc) {
 787                 log_print("non-version read from control device %zu", count);
 788                 return -EINVAL;
 789         }
 790
 791 #ifdef CONFIG_COMPAT
 792         if (count < sizeof(struct dlm_lock_result32))
 793 #else
 794         if (count < sizeof(struct dlm_lock_result))
 795 #endif
 796                 return -EINVAL;
 797
 798         /* do we really need this? can a read happen after a close? */
 799         if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
 800                 return -EINVAL;
 801
 802         spin_lock(&proc->asts_spin);
 803         if (list_empty(&proc->asts)) {
 804                 if (file->f_flags & O_NONBLOCK) {
 805                         spin_unlock(&proc->asts_spin);
 806                         return -EAGAIN;
 807                 }
 808
 809                 add_wait_queue(&proc->wait, &wait);
 810
 811         repeat:
 812                 set_current_state(TASK_INTERRUPTIBLE);
 813                 if (list_empty(&proc->asts) && !signal_pending(current)) {
 814                         spin_unlock(&proc->asts_spin);
 815                         schedule();
 816                         spin_lock(&proc->asts_spin);
 817                         goto repeat;
 818                 }
 819                 set_current_state(TASK_RUNNING);
 820                 remove_wait_queue(&proc->wait, &wait);
 821
 822                 if (signal_pending(current)) {
 823                         spin_unlock(&proc->asts_spin);
 824                         return -ERESTARTSYS;
 825                 }
 826         }
 827
 828         /* there may be both completion and blocking asts to return for
 829            the lkb, don't remove lkb from asts list unless no asts remain */
 830
 831         lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue);
 832
 833         if (lkb->lkb_ast_type & AST_COMP) {
 834                 lkb->lkb_ast_type &= ~AST_COMP;
 835                 type = AST_COMP;
 836         } else if (lkb->lkb_ast_type & AST_BAST) {
 837                 lkb->lkb_ast_type &= ~AST_BAST;
 838                 type = AST_BAST;
 839                 bmode = lkb->lkb_bastmode;
 840         }
 841
 842         if (!lkb->lkb_ast_type) {
 843                 list_del(&lkb->lkb_astqueue);
 844                 removed = 1;
 845         }
 846         spin_unlock(&proc->asts_spin);
 847
 848         ua = (struct dlm_user_args *)lkb->lkb_astparam;
 849         error = copy_result_to_user(ua,
 850                                 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
 851                                 type, bmode, buf, count);
 852
 853         /* removes reference for the proc->asts lists added by
 854            dlm_user_add_ast() and may result in the lkb being freed */
 855         if (removed)
 856                 dlm_put_lkb(lkb);
 857
 858         return error;
 859 }
 860
 861 static unsigned int device_poll(struct file *file, poll_table *wait)
 862 {
 863         struct dlm_user_proc *proc = file->private_data;
 864
 865         poll_wait(file, &proc->wait, wait);
 866
 867         spin_lock(&proc->asts_spin);
 868         if (!list_empty(&proc->asts)) {
 869                 spin_unlock(&proc->asts_spin);
 870                 return POLLIN | POLLRDNORM;
 871         }
 872         spin_unlock(&proc->asts_spin);
 873         return 0;
 874 }
 875
 876 static int ctl_device_open(struct inode *inode, struct file *file)
 877 {
 878         file->private_data = NULL;
 879         return 0;
 880 }
 881
 882 static int ctl_device_close(struct inode *inode, struct file *file)
 883 {
 884         return 0;
 885 }
 886
 887 static const struct file_operations device_fops = {
 888         .open    = device_open,
 889         .release = device_close,
 890         .read    = device_read,
 891         .write   = device_write,
 892         .poll    = device_poll,
 893         .owner   = THIS_MODULE,
 894 };
 895
 896 static const struct file_operations ctl_device_fops = {
 897         .open    = ctl_device_open,
 898         .release = ctl_device_close,
 899         .read    = device_read,
 900         .write   = device_write,
 901         .owner   = THIS_MODULE,
 902 };
 903
 904 static struct miscdevice ctl_device = {
 905         .name  = "dlm-control",
 906         .fops  = &ctl_device_fops,
 907         .minor = MISC_DYNAMIC_MINOR,
 908 };
 909
 910 int dlm_user_init(void)
 911 {
 912         int error;
 913
 914         error = misc_register(&ctl_device);
 915         if (error)
 916                 log_print("misc_register failed for control device");
 917
 918         return error;
 919 }
 920
 921 void dlm_user_exit(void)
 922 {
 923         misc_deregister(&ctl_device);
 924 }
 925