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 struct miscdevice ctl_device;
  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 {
  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                 memcpy(kb->i.lock.name, kb32->i.lock.name, kb->i.lock.namelen);
 116         }
 117 }
 118
 119 static void compat_output(struct dlm_lock_result *res,
 120                           struct dlm_lock_result32 *res32)
 121 {
 122         res32->version[0] = res->version[0];
 123         res32->version[1] = res->version[1];
 124         res32->version[2] = res->version[2];
 125
 126         res32->user_astaddr = (__u32)(long)res->user_astaddr;
 127         res32->user_astparam = (__u32)(long)res->user_astparam;
 128         res32->user_lksb = (__u32)(long)res->user_lksb;
 129         res32->bast_mode = res->bast_mode;
 130
 131         res32->lvb_offset = res->lvb_offset;
 132         res32->length = res->length;
 133
 134         res32->lksb.sb_status = res->lksb.sb_status;
 135         res32->lksb.sb_flags = res->lksb.sb_flags;
 136         res32->lksb.sb_lkid = res->lksb.sb_lkid;
 137         res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
 138 }
 139 #endif
 140
 141 /* Figure out if this lock is at the end of its life and no longer
 142    available for the application to use.  The lkb still exists until
 143    the final ast is read.  A lock becomes EOL in three situations:
 144      1. a noqueue request fails with EAGAIN
 145      2. an unlock completes with EUNLOCK
 146      3. a cancel of a waiting request completes with ECANCEL/EDEADLK
 147    An EOL lock needs to be removed from the process's list of locks.
 148    And we can't allow any new operation on an EOL lock.  This is
 149    not related to the lifetime of the lkb struct which is managed
 150    entirely by refcount. */
 151
 152 static int lkb_is_endoflife(struct dlm_lkb *lkb, int sb_status, int type)
 153 {
 154         switch (sb_status) {
 155         case -DLM_EUNLOCK:
 156                 return 1;
 157         case -DLM_ECANCEL:
 158         case -ETIMEDOUT:
 159         case -EDEADLK:
 160                 if (lkb->lkb_grmode == DLM_LOCK_IV)
 161                         return 1;
 162                 break;
 163         case -EAGAIN:
 164                 if (type == AST_COMP && lkb->lkb_grmode == DLM_LOCK_IV)
 165                         return 1;
 166                 break;
 167         }
 168         return 0;
 169 }
 170
 171 /* we could possibly check if the cancel of an orphan has resulted in the lkb
 172    being removed and then remove that lkb from the orphans list and free it */
 173
 174 void dlm_user_add_ast(struct dlm_lkb *lkb, int type)
 175 {
 176         struct dlm_ls *ls;
 177         struct dlm_user_args *ua;
 178         struct dlm_user_proc *proc;
 179         int eol = 0, ast_type;
 180
 181         if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
 182                 return;
 183
 184         ls = lkb->lkb_resource->res_ls;
 185         mutex_lock(&ls->ls_clear_proc_locks);
 186
 187         /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
 188            can't be delivered.  For ORPHAN's, dlm_clear_proc_locks() freed
 189            lkb->ua so we can't try to use it.  This second check is necessary
 190            for cases where a completion ast is received for an operation that
 191            began before clear_proc_locks did its cancel/unlock. */
 192
 193         if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
 194                 goto out;
 195
 196         DLM_ASSERT(lkb->lkb_astparam, dlm_print_lkb(lkb););
 197         ua = (struct dlm_user_args *)lkb->lkb_astparam;
 198         proc = ua->proc;
 199
 200         if (type == AST_BAST && ua->bastaddr == NULL)
 201                 goto out;
 202
 203         spin_lock(&proc->asts_spin);
 204
 205         ast_type = lkb->lkb_ast_type;
 206         lkb->lkb_ast_type |= type;
 207
 208         if (!ast_type) {
 209                 kref_get(&lkb->lkb_ref);
 210                 list_add_tail(&lkb->lkb_astqueue, &proc->asts);
 211                 wake_up_interruptible(&proc->wait);
 212         }
 213         if (type == AST_COMP && (ast_type & AST_COMP))
 214                 log_debug(ls, "ast overlap %x status %x %x",
 215                           lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags);
 216
 217         eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type);
 218         if (eol) {
 219                 lkb->lkb_ast_type &= ~AST_BAST;
 220                 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
 221         }
 222
 223         /* We want to copy the lvb to userspace when the completion
 224            ast is read if the status is 0, the lock has an lvb and
 225            lvb_ops says we should.  We could probably have set_lvb_lock()
 226            set update_user_lvb instead and not need old_mode */
 227
 228         if ((lkb->lkb_ast_type & AST_COMP) &&
 229             (lkb->lkb_lksb->sb_status == 0) &&
 230             lkb->lkb_lksb->sb_lvbptr &&
 231             dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1])
 232                 ua->update_user_lvb = 1;
 233         else
 234                 ua->update_user_lvb = 0;
 235
 236         spin_unlock(&proc->asts_spin);
 237
 238         if (eol) {
 239                 spin_lock(&ua->proc->locks_spin);
 240                 if (!list_empty(&lkb->lkb_ownqueue)) {
 241                         list_del_init(&lkb->lkb_ownqueue);
 242                         dlm_put_lkb(lkb);
 243                 }
 244                 spin_unlock(&ua->proc->locks_spin);
 245         }
 246  out:
 247         mutex_unlock(&ls->ls_clear_proc_locks);
 248 }
 249
 250 static int device_user_lock(struct dlm_user_proc *proc,
 251                             struct dlm_lock_params *params)
 252 {
 253         struct dlm_ls *ls;
 254         struct dlm_user_args *ua;
 255         int error = -ENOMEM;
 256
 257         ls = dlm_find_lockspace_local(proc->lockspace);
 258         if (!ls)
 259                 return -ENOENT;
 260
 261         if (!params->castaddr || !params->lksb) {
 262                 error = -EINVAL;
 263                 goto out;
 264         }
 265
 266         ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
 267         if (!ua)
 268                 goto out;
 269         ua->proc = proc;
 270         ua->user_lksb = params->lksb;
 271         ua->castparam = params->castparam;
 272         ua->castaddr = params->castaddr;
 273         ua->bastparam = params->bastparam;
 274         ua->bastaddr = params->bastaddr;
 275         ua->xid = params->xid;
 276
 277         if (params->flags & DLM_LKF_CONVERT)
 278                 error = dlm_user_convert(ls, ua,
 279                                          params->mode, params->flags,
 280                                          params->lkid, params->lvb,
 281                                          (unsigned long) params->timeout);
 282         else {
 283                 error = dlm_user_request(ls, ua,
 284                                          params->mode, params->flags,
 285                                          params->name, params->namelen,
 286                                          (unsigned long) params->timeout);
 287                 if (!error)
 288                         error = ua->lksb.sb_lkid;
 289         }
 290  out:
 291         dlm_put_lockspace(ls);
 292         return error;
 293 }
 294
 295 static int device_user_unlock(struct dlm_user_proc *proc,
 296                               struct dlm_lock_params *params)
 297 {
 298         struct dlm_ls *ls;
 299         struct dlm_user_args *ua;
 300         int error = -ENOMEM;
 301
 302         ls = dlm_find_lockspace_local(proc->lockspace);
 303         if (!ls)
 304                 return -ENOENT;
 305
 306         ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
 307         if (!ua)
 308                 goto out;
 309         ua->proc = proc;
 310         ua->user_lksb = params->lksb;
 311         ua->castparam = params->castparam;
 312         ua->castaddr = params->castaddr;
 313
 314         if (params->flags & DLM_LKF_CANCEL)
 315                 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
 316         else
 317                 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
 318                                         params->lvb);
 319  out:
 320         dlm_put_lockspace(ls);
 321         return error;
 322 }
 323
 324 static int device_user_deadlock(struct dlm_user_proc *proc,
 325                                 struct dlm_lock_params *params)
 326 {
 327         struct dlm_ls *ls;
 328         int error;
 329
 330         ls = dlm_find_lockspace_local(proc->lockspace);
 331         if (!ls)
 332                 return -ENOENT;
 333
 334         error = dlm_user_deadlock(ls, params->flags, params->lkid);
 335
 336         dlm_put_lockspace(ls);
 337         return error;
 338 }
 339
 340 static int create_misc_device(struct dlm_ls *ls, char *name)
 341 {
 342         int error, len;
 343
 344         error = -ENOMEM;
 345         len = strlen(name) + strlen(name_prefix) + 2;
 346         ls->ls_device.name = kzalloc(len, GFP_KERNEL);
 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 static int device_user_purge(struct dlm_user_proc *proc,
 364                              struct dlm_purge_params *params)
 365 {
 366         struct dlm_ls *ls;
 367         int error;
 368
 369         ls = dlm_find_lockspace_local(proc->lockspace);
 370         if (!ls)
 371                 return -ENOENT;
 372
 373         error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
 374
 375         dlm_put_lockspace(ls);
 376         return error;
 377 }
 378
 379 static int device_create_lockspace(struct dlm_lspace_params *params)
 380 {
 381         dlm_lockspace_t *lockspace;
 382         struct dlm_ls *ls;
 383         int error;
 384
 385         if (!capable(CAP_SYS_ADMIN))
 386                 return -EPERM;
 387
 388         error = dlm_new_lockspace(params->name, strlen(params->name),
 389                                   &lockspace, params->flags, DLM_USER_LVB_LEN);
 390         if (error)
 391                 return error;
 392
 393         ls = dlm_find_lockspace_local(lockspace);
 394         if (!ls)
 395                 return -ENOENT;
 396
 397         error = create_misc_device(ls, params->name);
 398         dlm_put_lockspace(ls);
 399
 400         if (error)
 401                 dlm_release_lockspace(lockspace, 0);
 402         else
 403                 error = ls->ls_device.minor;
 404
 405         return error;
 406 }
 407
 408 static int device_remove_lockspace(struct dlm_lspace_params *params)
 409 {
 410         dlm_lockspace_t *lockspace;
 411         struct dlm_ls *ls;
 412         int error, force = 0;
 413
 414         if (!capable(CAP_SYS_ADMIN))
 415                 return -EPERM;
 416
 417         ls = dlm_find_lockspace_device(params->minor);
 418         if (!ls)
 419                 return -ENOENT;
 420
 421         /* Deregister the misc device first, so we don't have
 422          * a device that's not attached to a lockspace. If
 423          * dlm_release_lockspace fails then we can recreate it
 424          */
 425         error = misc_deregister(&ls->ls_device);
 426         if (error) {
 427                 dlm_put_lockspace(ls);
 428                 goto out;
 429         }
 430         kfree(ls->ls_device.name);
 431
 432         if (params->flags & DLM_USER_LSFLG_FORCEFREE)
 433                 force = 2;
 434
 435         lockspace = ls->ls_local_handle;
 436
 437         /* dlm_release_lockspace waits for references to go to zero,
 438            so all processes will need to close their device for the ls
 439            before the release will procede */
 440
 441         dlm_put_lockspace(ls);
 442         error = dlm_release_lockspace(lockspace, force);
 443         if (error)
 444                 create_misc_device(ls, ls->ls_name);
 445  out:
 446         return error;
 447 }
 448
 449 /* Check the user's version matches ours */
 450 static int check_version(struct dlm_write_request *req)
 451 {
 452         if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
 453             (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
 454              req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
 455
 456                 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
 457                        "user (%d.%d.%d) kernel (%d.%d.%d)\n",
 458                        current->comm,
 459                        task_pid_nr(current),
 460                        req->version[0],
 461                        req->version[1],
 462                        req->version[2],
 463                        DLM_DEVICE_VERSION_MAJOR,
 464                        DLM_DEVICE_VERSION_MINOR,
 465                        DLM_DEVICE_VERSION_PATCH);
 466                 return -EINVAL;
 467         }
 468         return 0;
 469 }
 470
 471 /*
 472  * device_write
 473  *
 474  *   device_user_lock
 475  *     dlm_user_request -> request_lock
 476  *     dlm_user_convert -> convert_lock
 477  *
 478  *   device_user_unlock
 479  *     dlm_user_unlock -> unlock_lock
 480  *     dlm_user_cancel -> cancel_lock
 481  *
 482  *   device_create_lockspace
 483  *     dlm_new_lockspace
 484  *
 485  *   device_remove_lockspace
 486  *     dlm_release_lockspace
 487  */
 488
 489 /* a write to a lockspace device is a lock or unlock request, a write
 490    to the control device is to create/remove a lockspace */
 491
 492 static ssize_t device_write(struct file *file, const char __user *buf,
 493                             size_t count, loff_t *ppos)
 494 {
 495         struct dlm_user_proc *proc = file->private_data;
 496         struct dlm_write_request *kbuf;
 497         sigset_t tmpsig, allsigs;
 498         int error;
 499
 500 #ifdef CONFIG_COMPAT
 501         if (count < sizeof(struct dlm_write_request32))
 502 #else
 503         if (count < sizeof(struct dlm_write_request))
 504 #endif
 505                 return -EINVAL;
 506
 507         kbuf = kmalloc(count, GFP_KERNEL);
 508         if (!kbuf)
 509                 return -ENOMEM;
 510
 511         if (copy_from_user(kbuf, buf, count)) {
 512                 error = -EFAULT;
 513                 goto out_free;
 514         }
 515
 516         if (check_version(kbuf)) {
 517                 error = -EBADE;
 518                 goto out_free;
 519         }
 520
 521 #ifdef CONFIG_COMPAT
 522         if (!kbuf->is64bit) {
 523                 struct dlm_write_request32 *k32buf;
 524                 k32buf = (struct dlm_write_request32 *)kbuf;
 525                 kbuf = kmalloc(count + (sizeof(struct dlm_write_request) -
 526                                sizeof(struct dlm_write_request32)), GFP_KERNEL);
 527                 if (!kbuf)
 528                         return -ENOMEM;
 529
 530                 if (proc)
 531                         set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
 532                 compat_input(kbuf, k32buf);
 533                 kfree(k32buf);
 534         }
 535 #endif
 536
 537         /* do we really need this? can a write happen after a close? */
 538         if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
 539             test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
 540                 return -EINVAL;
 541
 542         sigfillset(&allsigs);
 543         sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
 544
 545         error = -EINVAL;
 546
 547         switch (kbuf->cmd)
 548         {
 549         case DLM_USER_LOCK:
 550                 if (!proc) {
 551                         log_print("no locking on control device");
 552                         goto out_sig;
 553                 }
 554                 error = device_user_lock(proc, &kbuf->i.lock);
 555                 break;
 556
 557         case DLM_USER_UNLOCK:
 558                 if (!proc) {
 559                         log_print("no locking on control device");
 560                         goto out_sig;
 561                 }
 562                 error = device_user_unlock(proc, &kbuf->i.lock);
 563                 break;
 564
 565         case DLM_USER_DEADLOCK:
 566                 if (!proc) {
 567                         log_print("no locking on control device");
 568                         goto out_sig;
 569                 }
 570                 error = device_user_deadlock(proc, &kbuf->i.lock);
 571                 break;
 572
 573         case DLM_USER_CREATE_LOCKSPACE:
 574                 if (proc) {
 575                         log_print("create/remove only on control device");
 576                         goto out_sig;
 577                 }
 578                 error = device_create_lockspace(&kbuf->i.lspace);
 579                 break;
 580
 581         case DLM_USER_REMOVE_LOCKSPACE:
 582                 if (proc) {
 583                         log_print("create/remove only on control device");
 584                         goto out_sig;
 585                 }
 586                 error = device_remove_lockspace(&kbuf->i.lspace);
 587                 break;
 588
 589         case DLM_USER_PURGE:
 590                 if (!proc) {
 591                         log_print("no locking on control device");
 592                         goto out_sig;
 593                 }
 594                 error = device_user_purge(proc, &kbuf->i.purge);
 595                 break;
 596
 597         default:
 598                 log_print("Unknown command passed to DLM device : %d\n",
 599                           kbuf->cmd);
 600         }
 601
 602  out_sig:
 603         sigprocmask(SIG_SETMASK, &tmpsig, NULL);
 604         recalc_sigpending();
 605  out_free:
 606         kfree(kbuf);
 607         return error;
 608 }
 609
 610 /* Every process that opens the lockspace device has its own "proc" structure
 611    hanging off the open file that's used to keep track of locks owned by the
 612    process and asts that need to be delivered to the process. */
 613
 614 static int device_open(struct inode *inode, struct file *file)
 615 {
 616         struct dlm_user_proc *proc;
 617         struct dlm_ls *ls;
 618
 619         ls = dlm_find_lockspace_device(iminor(inode));
 620         if (!ls)
 621                 return -ENOENT;
 622
 623         proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
 624         if (!proc) {
 625                 dlm_put_lockspace(ls);
 626                 return -ENOMEM;
 627         }
 628
 629         proc->lockspace = ls->ls_local_handle;
 630         INIT_LIST_HEAD(&proc->asts);
 631         INIT_LIST_HEAD(&proc->locks);
 632         INIT_LIST_HEAD(&proc->unlocking);
 633         spin_lock_init(&proc->asts_spin);
 634         spin_lock_init(&proc->locks_spin);
 635         init_waitqueue_head(&proc->wait);
 636         file->private_data = proc;
 637
 638         return 0;
 639 }
 640
 641 static int device_close(struct inode *inode, struct file *file)
 642 {
 643         struct dlm_user_proc *proc = file->private_data;
 644         struct dlm_ls *ls;
 645         sigset_t tmpsig, allsigs;
 646
 647         ls = dlm_find_lockspace_local(proc->lockspace);
 648         if (!ls)
 649                 return -ENOENT;
 650
 651         sigfillset(&allsigs);
 652         sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
 653
 654         set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
 655
 656         dlm_clear_proc_locks(ls, proc);
 657
 658         /* at this point no more lkb's should exist for this lockspace,
 659            so there's no chance of dlm_user_add_ast() being called and
 660            looking for lkb->ua->proc */
 661
 662         kfree(proc);
 663         file->private_data = NULL;
 664
 665         dlm_put_lockspace(ls);
 666         dlm_put_lockspace(ls);  /* for the find in device_open() */
 667
 668         /* FIXME: AUTOFREE: if this ls is no longer used do
 669            device_remove_lockspace() */
 670
 671         sigprocmask(SIG_SETMASK, &tmpsig, NULL);
 672         recalc_sigpending();
 673
 674         return 0;
 675 }
 676
 677 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type,
 678                                int bmode, char __user *buf, size_t count)
 679 {
 680 #ifdef CONFIG_COMPAT
 681         struct dlm_lock_result32 result32;
 682 #endif
 683         struct dlm_lock_result result;
 684         void *resultptr;
 685         int error=0;
 686         int len;
 687         int struct_len;
 688
 689         memset(&result, 0, sizeof(struct dlm_lock_result));
 690         result.version[0] = DLM_DEVICE_VERSION_MAJOR;
 691         result.version[1] = DLM_DEVICE_VERSION_MINOR;
 692         result.version[2] = DLM_DEVICE_VERSION_PATCH;
 693         memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
 694         result.user_lksb = ua->user_lksb;
 695
 696         /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
 697            in a conversion unless the conversion is successful.  See code
 698            in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
 699            notes that a new blocking AST address and parameter are set even if
 700            the conversion fails, so maybe we should just do that. */
 701
 702         if (type == AST_BAST) {
 703                 result.user_astaddr = ua->bastaddr;
 704                 result.user_astparam = ua->bastparam;
 705                 result.bast_mode = bmode;
 706         } else {
 707                 result.user_astaddr = ua->castaddr;
 708                 result.user_astparam = ua->castparam;
 709         }
 710
 711 #ifdef CONFIG_COMPAT
 712         if (compat)
 713                 len = sizeof(struct dlm_lock_result32);
 714         else
 715 #endif
 716                 len = sizeof(struct dlm_lock_result);
 717         struct_len = len;
 718
 719         /* copy lvb to userspace if there is one, it's been updated, and
 720            the user buffer has space for it */
 721
 722         if (ua->update_user_lvb && ua->lksb.sb_lvbptr &&
 723             count >= len + DLM_USER_LVB_LEN) {
 724                 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
 725                                  DLM_USER_LVB_LEN)) {
 726                         error = -EFAULT;
 727                         goto out;
 728                 }
 729
 730                 result.lvb_offset = len;
 731                 len += DLM_USER_LVB_LEN;
 732         }
 733
 734         result.length = len;
 735         resultptr = &result;
 736 #ifdef CONFIG_COMPAT
 737         if (compat) {
 738                 compat_output(&result, &result32);
 739                 resultptr = &result32;
 740         }
 741 #endif
 742
 743         if (copy_to_user(buf, resultptr, struct_len))
 744                 error = -EFAULT;
 745         else
 746                 error = len;
 747  out:
 748         return error;
 749 }
 750
 751 static int copy_version_to_user(char __user *buf, size_t count)
 752 {
 753         struct dlm_device_version ver;
 754
 755         memset(&ver, 0, sizeof(struct dlm_device_version));
 756         ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
 757         ver.version[1] = DLM_DEVICE_VERSION_MINOR;
 758         ver.version[2] = DLM_DEVICE_VERSION_PATCH;
 759
 760         if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
 761                 return -EFAULT;
 762         return sizeof(struct dlm_device_version);
 763 }
 764
 765 /* a read returns a single ast described in a struct dlm_lock_result */
 766
 767 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 768                            loff_t *ppos)
 769 {
 770         struct dlm_user_proc *proc = file->private_data;
 771         struct dlm_lkb *lkb;
 772         struct dlm_user_args *ua;
 773         DECLARE_WAITQUEUE(wait, current);
 774         int error, type=0, bmode=0, removed = 0;
 775
 776         if (count == sizeof(struct dlm_device_version)) {
 777                 error = copy_version_to_user(buf, count);
 778                 return error;
 779         }
 780
 781         if (!proc) {
 782                 log_print("non-version read from control device %zu", count);
 783                 return -EINVAL;
 784         }
 785
 786 #ifdef CONFIG_COMPAT
 787         if (count < sizeof(struct dlm_lock_result32))
 788 #else
 789         if (count < sizeof(struct dlm_lock_result))
 790 #endif
 791                 return -EINVAL;
 792
 793         /* do we really need this? can a read happen after a close? */
 794         if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
 795                 return -EINVAL;
 796
 797         spin_lock(&proc->asts_spin);
 798         if (list_empty(&proc->asts)) {
 799                 if (file->f_flags & O_NONBLOCK) {
 800                         spin_unlock(&proc->asts_spin);
 801                         return -EAGAIN;
 802                 }
 803
 804                 add_wait_queue(&proc->wait, &wait);
 805
 806         repeat:
 807                 set_current_state(TASK_INTERRUPTIBLE);
 808                 if (list_empty(&proc->asts) && !signal_pending(current)) {
 809                         spin_unlock(&proc->asts_spin);
 810                         schedule();
 811                         spin_lock(&proc->asts_spin);
 812                         goto repeat;
 813                 }
 814                 set_current_state(TASK_RUNNING);
 815                 remove_wait_queue(&proc->wait, &wait);
 816
 817                 if (signal_pending(current)) {
 818                         spin_unlock(&proc->asts_spin);
 819                         return -ERESTARTSYS;
 820                 }
 821         }
 822
 823         /* there may be both completion and blocking asts to return for
 824            the lkb, don't remove lkb from asts list unless no asts remain */
 825
 826         lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue);
 827
 828         if (lkb->lkb_ast_type & AST_COMP) {
 829                 lkb->lkb_ast_type &= ~AST_COMP;
 830                 type = AST_COMP;
 831         } else if (lkb->lkb_ast_type & AST_BAST) {
 832                 lkb->lkb_ast_type &= ~AST_BAST;
 833                 type = AST_BAST;
 834                 bmode = lkb->lkb_bastmode;
 835         }
 836
 837         if (!lkb->lkb_ast_type) {
 838                 list_del(&lkb->lkb_astqueue);
 839                 removed = 1;
 840         }
 841         spin_unlock(&proc->asts_spin);
 842
 843         ua = (struct dlm_user_args *)lkb->lkb_astparam;
 844         error = copy_result_to_user(ua,
 845                                 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
 846                                 type, bmode, buf, count);
 847
 848         /* removes reference for the proc->asts lists added by
 849            dlm_user_add_ast() and may result in the lkb being freed */
 850         if (removed)
 851                 dlm_put_lkb(lkb);
 852
 853         return error;
 854 }
 855
 856 static unsigned int device_poll(struct file *file, poll_table *wait)
 857 {
 858         struct dlm_user_proc *proc = file->private_data;
 859
 860         poll_wait(file, &proc->wait, wait);
 861
 862         spin_lock(&proc->asts_spin);
 863         if (!list_empty(&proc->asts)) {
 864                 spin_unlock(&proc->asts_spin);
 865                 return POLLIN | POLLRDNORM;
 866         }
 867         spin_unlock(&proc->asts_spin);
 868         return 0;
 869 }
 870
 871 static int ctl_device_open(struct inode *inode, struct file *file)
 872 {
 873         file->private_data = NULL;
 874         return 0;
 875 }
 876
 877 static int ctl_device_close(struct inode *inode, struct file *file)
 878 {
 879         return 0;
 880 }
 881
 882 static const struct file_operations device_fops = {
 883         .open    = device_open,
 884         .release = device_close,
 885         .read    = device_read,
 886         .write   = device_write,
 887         .poll    = device_poll,
 888         .owner   = THIS_MODULE,
 889 };
 890
 891 static const struct file_operations ctl_device_fops = {
 892         .open    = ctl_device_open,
 893         .release = ctl_device_close,
 894         .read    = device_read,
 895         .write   = device_write,
 896         .owner   = THIS_MODULE,
 897 };
 898
 899 int dlm_user_init(void)
 900 {
 901         int error;
 902
 903         ctl_device.name = "dlm-control";
 904         ctl_device.fops = &ctl_device_fops;
 905         ctl_device.minor = MISC_DYNAMIC_MINOR;
 906
 907         error = misc_register(&ctl_device);
 908         if (error)
 909                 log_print("misc_register failed for control device");
 910
 911         return error;
 912 }
 913
 914 void dlm_user_exit(void)
 915 {
 916         misc_deregister(&ctl_device);
 917 }
 918