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/smp_lock.h>
  19 #include <linux/dlm.h>
  20 #include <linux/dlm_device.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
  28 static const char name_prefix[] = "dlm";
  29 static const struct file_operations device_fops;
  30
  31 #ifdef CONFIG_COMPAT
  32
  33 struct dlm_lock_params32 {
  34         __u8 mode;
  35         __u8 namelen;
  36         __u16 unused;
  37         __u32 flags;
  38         __u32 lkid;
  39         __u32 parent;
  40         __u64 xid;
  41         __u64 timeout;
  42         __u32 castparam;
  43         __u32 castaddr;
  44         __u32 bastparam;
  45         __u32 bastaddr;
  46         __u32 lksb;
  47         char lvb[DLM_USER_LVB_LEN];
  48         char name[0];
  49 };
  50
  51 struct dlm_write_request32 {
  52         __u32 version[3];
  53         __u8 cmd;
  54         __u8 is64bit;
  55         __u8 unused[2];
  56
  57         union  {
  58                 struct dlm_lock_params32 lock;
  59                 struct dlm_lspace_params lspace;
  60                 struct dlm_purge_params purge;
  61         } i;
  62 };
  63
  64 struct dlm_lksb32 {
  65         __u32 sb_status;
  66         __u32 sb_lkid;
  67         __u8 sb_flags;
  68         __u32 sb_lvbptr;
  69 };
  70
  71 struct dlm_lock_result32 {
  72         __u32 version[3];
  73         __u32 length;
  74         __u32 user_astaddr;
  75         __u32 user_astparam;
  76         __u32 user_lksb;
  77         struct dlm_lksb32 lksb;
  78         __u8 bast_mode;
  79         __u8 unused[3];
  80         /* Offsets may be zero if no data is present */
  81         __u32 lvb_offset;
  82 };
  83
  84 static void compat_input(struct dlm_write_request *kb,
  85                          struct dlm_write_request32 *kb32,
  86                          size_t count)
  87 {
  88         kb->version[0] = kb32->version[0];
  89         kb->version[1] = kb32->version[1];
  90         kb->version[2] = kb32->version[2];
  91
  92         kb->cmd = kb32->cmd;
  93         kb->is64bit = kb32->is64bit;
  94         if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
  95             kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
  96                 kb->i.lspace.flags = kb32->i.lspace.flags;
  97                 kb->i.lspace.minor = kb32->i.lspace.minor;
  98                 memcpy(kb->i.lspace.name, kb32->i.lspace.name, count -
  99                         offsetof(struct dlm_write_request32, i.lspace.name));
 100         } else if (kb->cmd == DLM_USER_PURGE) {
 101                 kb->i.purge.nodeid = kb32->i.purge.nodeid;
 102                 kb->i.purge.pid = kb32->i.purge.pid;
 103         } else {
 104                 kb->i.lock.mode = kb32->i.lock.mode;
 105                 kb->i.lock.namelen = kb32->i.lock.namelen;
 106                 kb->i.lock.flags = kb32->i.lock.flags;
 107                 kb->i.lock.lkid = kb32->i.lock.lkid;
 108                 kb->i.lock.parent = kb32->i.lock.parent;
 109                 kb->i.lock.xid = kb32->i.lock.xid;
 110                 kb->i.lock.timeout = kb32->i.lock.timeout;
 111                 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
 112                 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
 113                 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
 114                 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
 115                 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
 116                 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
 117                 memcpy(kb->i.lock.name, kb32->i.lock.name, count -
 118                         offsetof(struct dlm_write_request32, i.lock.name));
 119         }
 120 }
 121
 122 static void compat_output(struct dlm_lock_result *res,
 123                           struct dlm_lock_result32 *res32)
 124 {
 125         res32->version[0] = res->version[0];
 126         res32->version[1] = res->version[1];
 127         res32->version[2] = res->version[2];
 128
 129         res32->user_astaddr = (__u32)(long)res->user_astaddr;
 130         res32->user_astparam = (__u32)(long)res->user_astparam;
 131         res32->user_lksb = (__u32)(long)res->user_lksb;
 132         res32->bast_mode = res->bast_mode;
 133
 134         res32->lvb_offset = res->lvb_offset;
 135         res32->length = res->length;
 136
 137         res32->lksb.sb_status = res->lksb.sb_status;
 138         res32->lksb.sb_flags = res->lksb.sb_flags;
 139         res32->lksb.sb_lkid = res->lksb.sb_lkid;
 140         res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
 141 }
 142 #endif
 143
 144 /* Figure out if this lock is at the end of its life and no longer
 145    available for the application to use.  The lkb still exists until
 146    the final ast is read.  A lock becomes EOL in three situations:
 147      1. a noqueue request fails with EAGAIN
 148      2. an unlock completes with EUNLOCK
 149      3. a cancel of a waiting request completes with ECANCEL/EDEADLK
 150    An EOL lock needs to be removed from the process's list of locks.
 151    And we can't allow any new operation on an EOL lock.  This is
 152    not related to the lifetime of the lkb struct which is managed
 153    entirely by refcount. */
 154
 155 static int lkb_is_endoflife(struct dlm_lkb *lkb, int sb_status, int type)
 156 {
 157         switch (sb_status) {
 158         case -DLM_EUNLOCK:
 159                 return 1;
 160         case -DLM_ECANCEL:
 161         case -ETIMEDOUT:
 162         case -EDEADLK:
 163                 if (lkb->lkb_grmode == DLM_LOCK_IV)
 164                         return 1;
 165                 break;
 166         case -EAGAIN:
 167                 if (type == AST_COMP && lkb->lkb_grmode == DLM_LOCK_IV)
 168                         return 1;
 169                 break;
 170         }
 171         return 0;
 172 }
 173
 174 /* we could possibly check if the cancel of an orphan has resulted in the lkb
 175    being removed and then remove that lkb from the orphans list and free it */
 176
 177 void dlm_user_add_ast(struct dlm_lkb *lkb, int type)
 178 {
 179         struct dlm_ls *ls;
 180         struct dlm_user_args *ua;
 181         struct dlm_user_proc *proc;
 182         int eol = 0, ast_type;
 183
 184         if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
 185                 return;
 186
 187         ls = lkb->lkb_resource->res_ls;
 188         mutex_lock(&ls->ls_clear_proc_locks);
 189
 190         /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
 191            can't be delivered.  For ORPHAN's, dlm_clear_proc_locks() freed
 192            lkb->ua so we can't try to use it.  This second check is necessary
 193            for cases where a completion ast is received for an operation that
 194            began before clear_proc_locks did its cancel/unlock. */
 195
 196         if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
 197                 goto out;
 198
 199         DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
 200         ua = lkb->lkb_ua;
 201         proc = ua->proc;
 202
 203         if (type == AST_BAST && ua->bastaddr == NULL)
 204                 goto out;
 205
 206         spin_lock(&proc->asts_spin);
 207
 208         ast_type = lkb->lkb_ast_type;
 209         lkb->lkb_ast_type |= type;
 210
 211         if (!ast_type) {
 212                 kref_get(&lkb->lkb_ref);
 213                 list_add_tail(&lkb->lkb_astqueue, &proc->asts);
 214                 wake_up_interruptible(&proc->wait);
 215         }
 216         if (type == AST_COMP && (ast_type & AST_COMP))
 217                 log_debug(ls, "ast overlap %x status %x %x",
 218                           lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags);
 219
 220         eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type);
 221         if (eol) {
 222                 lkb->lkb_ast_type &= ~AST_BAST;
 223                 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
 224         }
 225
 226         /* We want to copy the lvb to userspace when the completion
 227            ast is read if the status is 0, the lock has an lvb and
 228            lvb_ops says we should.  We could probably have set_lvb_lock()
 229            set update_user_lvb instead and not need old_mode */
 230
 231         if ((lkb->lkb_ast_type & AST_COMP) &&
 232             (lkb->lkb_lksb->sb_status == 0) &&
 233             lkb->lkb_lksb->sb_lvbptr &&
 234             dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1])
 235                 ua->update_user_lvb = 1;
 236         else
 237                 ua->update_user_lvb = 0;
 238
 239         spin_unlock(&proc->asts_spin);
 240
 241         if (eol) {
 242                 spin_lock(&proc->locks_spin);
 243                 if (!list_empty(&lkb->lkb_ownqueue)) {
 244                         list_del_init(&lkb->lkb_ownqueue);
 245                         dlm_put_lkb(lkb);
 246                 }
 247                 spin_unlock(&proc->locks_spin);
 248         }
 249  out:
 250         mutex_unlock(&ls->ls_clear_proc_locks);
 251 }
 252
 253 static int device_user_lock(struct dlm_user_proc *proc,
 254                             struct dlm_lock_params *params)
 255 {
 256         struct dlm_ls *ls;
 257         struct dlm_user_args *ua;
 258         int error = -ENOMEM;
 259
 260         ls = dlm_find_lockspace_local(proc->lockspace);
 261         if (!ls)
 262                 return -ENOENT;
 263
 264         if (!params->castaddr || !params->lksb) {
 265                 error = -EINVAL;
 266                 goto out;
 267         }
 268
 269         ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
 270         if (!ua)
 271                 goto out;
 272         ua->proc = proc;
 273         ua->user_lksb = params->lksb;
 274         ua->castparam = params->castparam;
 275         ua->castaddr = params->castaddr;
 276         ua->bastparam = params->bastparam;
 277         ua->bastaddr = params->bastaddr;
 278         ua->xid = params->xid;
 279
 280         if (params->flags & DLM_LKF_CONVERT)
 281                 error = dlm_user_convert(ls, ua,
 282                                          params->mode, params->flags,
 283                                          params->lkid, params->lvb,
 284                                          (unsigned long) params->timeout);
 285         else {
 286                 error = dlm_user_request(ls, ua,
 287                                          params->mode, params->flags,
 288                                          params->name, params->namelen,
 289                                          (unsigned long) params->timeout);
 290                 if (!error)
 291                         error = ua->lksb.sb_lkid;
 292         }
 293  out:
 294         dlm_put_lockspace(ls);
 295         return error;
 296 }
 297
 298 static int device_user_unlock(struct dlm_user_proc *proc,
 299                               struct dlm_lock_params *params)
 300 {
 301         struct dlm_ls *ls;
 302         struct dlm_user_args *ua;
 303         int error = -ENOMEM;
 304
 305         ls = dlm_find_lockspace_local(proc->lockspace);
 306         if (!ls)
 307                 return -ENOENT;
 308
 309         ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
 310         if (!ua)
 311                 goto out;
 312         ua->proc = proc;
 313         ua->user_lksb = params->lksb;
 314         ua->castparam = params->castparam;
 315         ua->castaddr = params->castaddr;
 316
 317         if (params->flags & DLM_LKF_CANCEL)
 318                 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
 319         else
 320                 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
 321                                         params->lvb);
 322  out:
 323         dlm_put_lockspace(ls);
 324         return error;
 325 }
 326
 327 static int device_user_deadlock(struct dlm_user_proc *proc,
 328                                 struct dlm_lock_params *params)
 329 {
 330         struct dlm_ls *ls;
 331         int error;
 332
 333         ls = dlm_find_lockspace_local(proc->lockspace);
 334         if (!ls)
 335                 return -ENOENT;
 336
 337         error = dlm_user_deadlock(ls, params->flags, params->lkid);
 338
 339         dlm_put_lockspace(ls);
 340         return error;
 341 }
 342
 343 static int create_misc_device(struct dlm_ls *ls, char *name)
 344 {
 345         int error, len;
 346
 347         error = -ENOMEM;
 348         len = strlen(name) + strlen(name_prefix) + 2;
 349         ls->ls_device.name = kzalloc(len, GFP_KERNEL);
 350         if (!ls->ls_device.name)
 351                 goto fail;
 352
 353         snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
 354                  name);
 355         ls->ls_device.fops = &device_fops;
 356         ls->ls_device.minor = MISC_DYNAMIC_MINOR;
 357
 358         error = misc_register(&ls->ls_device);
 359         if (error) {
 360                 kfree(ls->ls_device.name);
 361         }
 362 fail:
 363         return error;
 364 }
 365
 366 static int device_user_purge(struct dlm_user_proc *proc,
 367                              struct dlm_purge_params *params)
 368 {
 369         struct dlm_ls *ls;
 370         int error;
 371
 372         ls = dlm_find_lockspace_local(proc->lockspace);
 373         if (!ls)
 374                 return -ENOENT;
 375
 376         error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
 377
 378         dlm_put_lockspace(ls);
 379         return error;
 380 }
 381
 382 static int device_create_lockspace(struct dlm_lspace_params *params)
 383 {
 384         dlm_lockspace_t *lockspace;
 385         struct dlm_ls *ls;
 386         int error;
 387
 388         if (!capable(CAP_SYS_ADMIN))
 389                 return -EPERM;
 390
 391         error = dlm_new_lockspace(params->name, strlen(params->name),
 392                                   &lockspace, params->flags, DLM_USER_LVB_LEN);
 393         if (error)
 394                 return error;
 395
 396         ls = dlm_find_lockspace_local(lockspace);
 397         if (!ls)
 398                 return -ENOENT;
 399
 400         error = create_misc_device(ls, params->name);
 401         dlm_put_lockspace(ls);
 402
 403         if (error)
 404                 dlm_release_lockspace(lockspace, 0);
 405         else
 406                 error = ls->ls_device.minor;
 407
 408         return error;
 409 }
 410
 411 static int device_remove_lockspace(struct dlm_lspace_params *params)
 412 {
 413         dlm_lockspace_t *lockspace;
 414         struct dlm_ls *ls;
 415         int error, force = 0;
 416
 417         if (!capable(CAP_SYS_ADMIN))
 418                 return -EPERM;
 419
 420         ls = dlm_find_lockspace_device(params->minor);
 421         if (!ls)
 422                 return -ENOENT;
 423
 424         /* Deregister the misc device first, so we don't have
 425          * a device that's not attached to a lockspace. If
 426          * dlm_release_lockspace fails then we can recreate it
 427          */
 428         error = misc_deregister(&ls->ls_device);
 429         if (error) {
 430                 dlm_put_lockspace(ls);
 431                 goto out;
 432         }
 433         kfree(ls->ls_device.name);
 434
 435         if (params->flags & DLM_USER_LSFLG_FORCEFREE)
 436                 force = 2;
 437
 438         lockspace = ls->ls_local_handle;
 439
 440         /* dlm_release_lockspace waits for references to go to zero,
 441            so all processes will need to close their device for the ls
 442            before the release will procede */
 443
 444         dlm_put_lockspace(ls);
 445         error = dlm_release_lockspace(lockspace, force);
 446         if (error)
 447                 create_misc_device(ls, ls->ls_name);
 448  out:
 449         return error;
 450 }
 451
 452 /* Check the user's version matches ours */
 453 static int check_version(struct dlm_write_request *req)
 454 {
 455         if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
 456             (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
 457              req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
 458
 459                 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
 460                        "user (%d.%d.%d) kernel (%d.%d.%d)\n",
 461                        current->comm,
 462                        task_pid_nr(current),
 463                        req->version[0],
 464                        req->version[1],
 465                        req->version[2],
 466                        DLM_DEVICE_VERSION_MAJOR,
 467                        DLM_DEVICE_VERSION_MINOR,
 468                        DLM_DEVICE_VERSION_PATCH);
 469                 return -EINVAL;
 470         }
 471         return 0;
 472 }
 473
 474 /*
 475  * device_write
 476  *
 477  *   device_user_lock
 478  *     dlm_user_request -> request_lock
 479  *     dlm_user_convert -> convert_lock
 480  *
 481  *   device_user_unlock
 482  *     dlm_user_unlock -> unlock_lock
 483  *     dlm_user_cancel -> cancel_lock
 484  *
 485  *   device_create_lockspace
 486  *     dlm_new_lockspace
 487  *
 488  *   device_remove_lockspace
 489  *     dlm_release_lockspace
 490  */
 491
 492 /* a write to a lockspace device is a lock or unlock request, a write
 493    to the control device is to create/remove a lockspace */
 494
 495 static ssize_t device_write(struct file *file, const char __user *buf,
 496                             size_t count, loff_t *ppos)
 497 {
 498         struct dlm_user_proc *proc = file->private_data;
 499         struct dlm_write_request *kbuf;
 500         sigset_t tmpsig, allsigs;
 501         int error;
 502
 503 #ifdef CONFIG_COMPAT
 504         if (count < sizeof(struct dlm_write_request32))
 505 #else
 506         if (count < sizeof(struct dlm_write_request))
 507 #endif
 508                 return -EINVAL;
 509
 510         kbuf = kzalloc(count + 1, GFP_KERNEL);
 511         if (!kbuf)
 512                 return -ENOMEM;
 513
 514         if (copy_from_user(kbuf, buf, count)) {
 515                 error = -EFAULT;
 516                 goto out_free;
 517         }
 518
 519         if (check_version(kbuf)) {
 520                 error = -EBADE;
 521                 goto out_free;
 522         }
 523
 524 #ifdef CONFIG_COMPAT
 525         if (!kbuf->is64bit) {
 526                 struct dlm_write_request32 *k32buf;
 527                 k32buf = (struct dlm_write_request32 *)kbuf;
 528                 kbuf = kmalloc(count + 1 + (sizeof(struct dlm_write_request) -
 529                                sizeof(struct dlm_write_request32)), GFP_KERNEL);
 530                 if (!kbuf) {
 531                         kfree(k32buf);
 532                         return -ENOMEM;
 533                 }
 534
 535                 if (proc)
 536                         set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
 537                 compat_input(kbuf, k32buf, count + 1);
 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             (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
 545                 error = -EINVAL;
 546                 goto out_free;
 547         }
 548
 549         sigfillset(&allsigs);
 550         sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
 551
 552         error = -EINVAL;
 553
 554         switch (kbuf->cmd)
 555         {
 556         case DLM_USER_LOCK:
 557                 if (!proc) {
 558                         log_print("no locking on control device");
 559                         goto out_sig;
 560                 }
 561                 error = device_user_lock(proc, &kbuf->i.lock);
 562                 break;
 563
 564         case DLM_USER_UNLOCK:
 565                 if (!proc) {
 566                         log_print("no locking on control device");
 567                         goto out_sig;
 568                 }
 569                 error = device_user_unlock(proc, &kbuf->i.lock);
 570                 break;
 571
 572         case DLM_USER_DEADLOCK:
 573                 if (!proc) {
 574                         log_print("no locking on control device");
 575                         goto out_sig;
 576                 }
 577                 error = device_user_deadlock(proc, &kbuf->i.lock);
 578                 break;
 579
 580         case DLM_USER_CREATE_LOCKSPACE:
 581                 if (proc) {
 582                         log_print("create/remove only on control device");
 583                         goto out_sig;
 584                 }
 585                 error = device_create_lockspace(&kbuf->i.lspace);
 586                 break;
 587
 588         case DLM_USER_REMOVE_LOCKSPACE:
 589                 if (proc) {
 590                         log_print("create/remove only on control device");
 591                         goto out_sig;
 592                 }
 593                 error = device_remove_lockspace(&kbuf->i.lspace);
 594                 break;
 595
 596         case DLM_USER_PURGE:
 597                 if (!proc) {
 598                         log_print("no locking on control device");
 599                         goto out_sig;
 600                 }
 601                 error = device_user_purge(proc, &kbuf->i.purge);
 602                 break;
 603
 604         default:
 605                 log_print("Unknown command passed to DLM device : %d\n",
 606                           kbuf->cmd);
 607         }
 608
 609  out_sig:
 610         sigprocmask(SIG_SETMASK, &tmpsig, NULL);
 611         recalc_sigpending();
 612  out_free:
 613         kfree(kbuf);
 614         return error;
 615 }
 616
 617 /* Every process that opens the lockspace device has its own "proc" structure
 618    hanging off the open file that's used to keep track of locks owned by the
 619    process and asts that need to be delivered to the process. */
 620
 621 static int device_open(struct inode *inode, struct file *file)
 622 {
 623         struct dlm_user_proc *proc;
 624         struct dlm_ls *ls;
 625
 626         lock_kernel();
 627         ls = dlm_find_lockspace_device(iminor(inode));
 628         if (!ls) {
 629                 unlock_kernel();
 630                 return -ENOENT;
 631         }
 632
 633         proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
 634         if (!proc) {
 635                 dlm_put_lockspace(ls);
 636                 unlock_kernel();
 637                 return -ENOMEM;
 638         }
 639
 640         proc->lockspace = ls->ls_local_handle;
 641         INIT_LIST_HEAD(&proc->asts);
 642         INIT_LIST_HEAD(&proc->locks);
 643         INIT_LIST_HEAD(&proc->unlocking);
 644         spin_lock_init(&proc->asts_spin);
 645         spin_lock_init(&proc->locks_spin);
 646         init_waitqueue_head(&proc->wait);
 647         file->private_data = proc;
 648         unlock_kernel();
 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         sigset_t tmpsig, allsigs;
 658
 659         ls = dlm_find_lockspace_local(proc->lockspace);
 660         if (!ls)
 661                 return -ENOENT;
 662
 663         sigfillset(&allsigs);
 664         sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
 665
 666         set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
 667
 668         dlm_clear_proc_locks(ls, proc);
 669
 670         /* at this point no more lkb's should exist for this lockspace,
 671            so there's no chance of dlm_user_add_ast() being called and
 672            looking for lkb->ua->proc */
 673
 674         kfree(proc);
 675         file->private_data = NULL;
 676
 677         dlm_put_lockspace(ls);
 678         dlm_put_lockspace(ls);  /* for the find in device_open() */
 679
 680         /* FIXME: AUTOFREE: if this ls is no longer used do
 681            device_remove_lockspace() */
 682
 683         sigprocmask(SIG_SETMASK, &tmpsig, NULL);
 684         recalc_sigpending();
 685
 686         return 0;
 687 }
 688
 689 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type,
 690                                int bmode, char __user *buf, size_t count)
 691 {
 692 #ifdef CONFIG_COMPAT
 693         struct dlm_lock_result32 result32;
 694 #endif
 695         struct dlm_lock_result result;
 696         void *resultptr;
 697         int error=0;
 698         int len;
 699         int struct_len;
 700
 701         memset(&result, 0, sizeof(struct dlm_lock_result));
 702         result.version[0] = DLM_DEVICE_VERSION_MAJOR;
 703         result.version[1] = DLM_DEVICE_VERSION_MINOR;
 704         result.version[2] = DLM_DEVICE_VERSION_PATCH;
 705         memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
 706         result.user_lksb = ua->user_lksb;
 707
 708         /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
 709            in a conversion unless the conversion is successful.  See code
 710            in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
 711            notes that a new blocking AST address and parameter are set even if
 712            the conversion fails, so maybe we should just do that. */
 713
 714         if (type == AST_BAST) {
 715                 result.user_astaddr = ua->bastaddr;
 716                 result.user_astparam = ua->bastparam;
 717                 result.bast_mode = bmode;
 718         } else {
 719                 result.user_astaddr = ua->castaddr;
 720                 result.user_astparam = ua->castparam;
 721         }
 722
 723 #ifdef CONFIG_COMPAT
 724         if (compat)
 725                 len = sizeof(struct dlm_lock_result32);
 726         else
 727 #endif
 728                 len = sizeof(struct dlm_lock_result);
 729         struct_len = len;
 730
 731         /* copy lvb to userspace if there is one, it's been updated, and
 732            the user buffer has space for it */
 733
 734         if (ua->update_user_lvb && ua->lksb.sb_lvbptr &&
 735             count >= len + DLM_USER_LVB_LEN) {
 736                 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
 737                                  DLM_USER_LVB_LEN)) {
 738                         error = -EFAULT;
 739                         goto out;
 740                 }
 741
 742                 result.lvb_offset = len;
 743                 len += DLM_USER_LVB_LEN;
 744         }
 745
 746         result.length = len;
 747         resultptr = &result;
 748 #ifdef CONFIG_COMPAT
 749         if (compat) {
 750                 compat_output(&result, &result32);
 751                 resultptr = &result32;
 752         }
 753 #endif
 754
 755         if (copy_to_user(buf, resultptr, struct_len))
 756                 error = -EFAULT;
 757         else
 758                 error = len;
 759  out:
 760         return error;
 761 }
 762
 763 static int copy_version_to_user(char __user *buf, size_t count)
 764 {
 765         struct dlm_device_version ver;
 766
 767         memset(&ver, 0, sizeof(struct dlm_device_version));
 768         ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
 769         ver.version[1] = DLM_DEVICE_VERSION_MINOR;
 770         ver.version[2] = DLM_DEVICE_VERSION_PATCH;
 771
 772         if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
 773                 return -EFAULT;
 774         return sizeof(struct dlm_device_version);
 775 }
 776
 777 /* a read returns a single ast described in a struct dlm_lock_result */
 778
 779 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 780                            loff_t *ppos)
 781 {
 782         struct dlm_user_proc *proc = file->private_data;
 783         struct dlm_lkb *lkb;
 784         DECLARE_WAITQUEUE(wait, current);
 785         int error, type=0, bmode=0, removed = 0;
 786
 787         if (count == sizeof(struct dlm_device_version)) {
 788                 error = copy_version_to_user(buf, count);
 789                 return error;
 790         }
 791
 792         if (!proc) {
 793                 log_print("non-version read from control device %zu", count);
 794                 return -EINVAL;
 795         }
 796
 797 #ifdef CONFIG_COMPAT
 798         if (count < sizeof(struct dlm_lock_result32))
 799 #else
 800         if (count < sizeof(struct dlm_lock_result))
 801 #endif
 802                 return -EINVAL;
 803
 804         /* do we really need this? can a read happen after a close? */
 805         if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
 806                 return -EINVAL;
 807
 808         spin_lock(&proc->asts_spin);
 809         if (list_empty(&proc->asts)) {
 810                 if (file->f_flags & O_NONBLOCK) {
 811                         spin_unlock(&proc->asts_spin);
 812                         return -EAGAIN;
 813                 }
 814
 815                 add_wait_queue(&proc->wait, &wait);
 816
 817         repeat:
 818                 set_current_state(TASK_INTERRUPTIBLE);
 819                 if (list_empty(&proc->asts) && !signal_pending(current)) {
 820                         spin_unlock(&proc->asts_spin);
 821                         schedule();
 822                         spin_lock(&proc->asts_spin);
 823                         goto repeat;
 824                 }
 825                 set_current_state(TASK_RUNNING);
 826                 remove_wait_queue(&proc->wait, &wait);
 827
 828                 if (signal_pending(current)) {
 829                         spin_unlock(&proc->asts_spin);
 830                         return -ERESTARTSYS;
 831                 }
 832         }
 833
 834         /* there may be both completion and blocking asts to return for
 835            the lkb, don't remove lkb from asts list unless no asts remain */
 836
 837         lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue);
 838
 839         if (lkb->lkb_ast_type & AST_COMP) {
 840                 lkb->lkb_ast_type &= ~AST_COMP;
 841                 type = AST_COMP;
 842         } else if (lkb->lkb_ast_type & AST_BAST) {
 843                 lkb->lkb_ast_type &= ~AST_BAST;
 844                 type = AST_BAST;
 845                 bmode = lkb->lkb_bastmode;
 846         }
 847
 848         if (!lkb->lkb_ast_type) {
 849                 list_del(&lkb->lkb_astqueue);
 850                 removed = 1;
 851         }
 852         spin_unlock(&proc->asts_spin);
 853
 854         error = copy_result_to_user(lkb->lkb_ua,
 855                                 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
 856                                 type, bmode, buf, count);
 857
 858         /* removes reference for the proc->asts lists added by
 859            dlm_user_add_ast() and may result in the lkb being freed */
 860         if (removed)
 861                 dlm_put_lkb(lkb);
 862
 863         return error;
 864 }
 865
 866 static unsigned int device_poll(struct file *file, poll_table *wait)
 867 {
 868         struct dlm_user_proc *proc = file->private_data;
 869
 870         poll_wait(file, &proc->wait, wait);
 871
 872         spin_lock(&proc->asts_spin);
 873         if (!list_empty(&proc->asts)) {
 874                 spin_unlock(&proc->asts_spin);
 875                 return POLLIN | POLLRDNORM;
 876         }
 877         spin_unlock(&proc->asts_spin);
 878         return 0;
 879 }
 880
 881 static int ctl_device_open(struct inode *inode, struct file *file)
 882 {
 883         cycle_kernel_lock();
 884         file->private_data = NULL;
 885         return 0;
 886 }
 887
 888 static int ctl_device_close(struct inode *inode, struct file *file)
 889 {
 890         return 0;
 891 }
 892
 893 static const struct file_operations device_fops = {
 894         .open    = device_open,
 895         .release = device_close,
 896         .read    = device_read,
 897         .write   = device_write,
 898         .poll    = device_poll,
 899         .owner   = THIS_MODULE,
 900 };
 901
 902 static const struct file_operations ctl_device_fops = {
 903         .open    = ctl_device_open,
 904         .release = ctl_device_close,
 905         .read    = device_read,
 906         .write   = device_write,
 907         .owner   = THIS_MODULE,
 908 };
 909
 910 static struct miscdevice ctl_device = {
 911         .name  = "dlm-control",
 912         .fops  = &ctl_device_fops,
 913         .minor = MISC_DYNAMIC_MINOR,
 914 };
 915
 916 int __init dlm_user_init(void)
 917 {
 918         int error;
 919
 920         error = misc_register(&ctl_device);
 921         if (error)
 922                 log_print("misc_register failed for control device");
 923
 924         return error;
 925 }
 926
 927 void dlm_user_exit(void)
 928 {
 929         misc_deregister(&ctl_device);
 930 }
 931