linux/fs/dlm/user.c
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   1/*
   2 * Copyright (C) 2006-2010 Red Hat, Inc.  All rights reserved.
   3 *
   4 * This copyrighted material is made available to anyone wishing to use,
   5 * modify, copy, or redistribute it subject to the terms and conditions
   6 * of the GNU General Public License v.2.
   7 */
   8
   9#include <linux/miscdevice.h>
  10#include <linux/init.h>
  11#include <linux/wait.h>
  12#include <linux/module.h>
  13#include <linux/file.h>
  14#include <linux/fs.h>
  15#include <linux/poll.h>
  16#include <linux/signal.h>
  17#include <linux/spinlock.h>
  18#include <linux/dlm.h>
  19#include <linux/dlm_device.h>
  20#include <linux/slab.h>
  21
  22#include "dlm_internal.h"
  23#include "lockspace.h"
  24#include "lock.h"
  25#include "lvb_table.h"
  26#include "user.h"
  27#include "ast.h"
  28
  29static const char name_prefix[] = "dlm";
  30static const struct file_operations device_fops;
  31static atomic_t dlm_monitor_opened;
  32static int dlm_monitor_unused = 1;
  33
  34#ifdef CONFIG_COMPAT
  35
  36struct dlm_lock_params32 {
  37        __u8 mode;
  38        __u8 namelen;
  39        __u16 unused;
  40        __u32 flags;
  41        __u32 lkid;
  42        __u32 parent;
  43        __u64 xid;
  44        __u64 timeout;
  45        __u32 castparam;
  46        __u32 castaddr;
  47        __u32 bastparam;
  48        __u32 bastaddr;
  49        __u32 lksb;
  50        char lvb[DLM_USER_LVB_LEN];
  51        char name[0];
  52};
  53
  54struct dlm_write_request32 {
  55        __u32 version[3];
  56        __u8 cmd;
  57        __u8 is64bit;
  58        __u8 unused[2];
  59
  60        union  {
  61                struct dlm_lock_params32 lock;
  62                struct dlm_lspace_params lspace;
  63                struct dlm_purge_params purge;
  64        } i;
  65};
  66
  67struct dlm_lksb32 {
  68        __u32 sb_status;
  69        __u32 sb_lkid;
  70        __u8 sb_flags;
  71        __u32 sb_lvbptr;
  72};
  73
  74struct dlm_lock_result32 {
  75        __u32 version[3];
  76        __u32 length;
  77        __u32 user_astaddr;
  78        __u32 user_astparam;
  79        __u32 user_lksb;
  80        struct dlm_lksb32 lksb;
  81        __u8 bast_mode;
  82        __u8 unused[3];
  83        /* Offsets may be zero if no data is present */
  84        __u32 lvb_offset;
  85};
  86
  87static void compat_input(struct dlm_write_request *kb,
  88                         struct dlm_write_request32 *kb32,
  89                         int namelen)
  90{
  91        kb->version[0] = kb32->version[0];
  92        kb->version[1] = kb32->version[1];
  93        kb->version[2] = kb32->version[2];
  94
  95        kb->cmd = kb32->cmd;
  96        kb->is64bit = kb32->is64bit;
  97        if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
  98            kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
  99                kb->i.lspace.flags = kb32->i.lspace.flags;
 100                kb->i.lspace.minor = kb32->i.lspace.minor;
 101                memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
 102        } else if (kb->cmd == DLM_USER_PURGE) {
 103                kb->i.purge.nodeid = kb32->i.purge.nodeid;
 104                kb->i.purge.pid = kb32->i.purge.pid;
 105        } else {
 106                kb->i.lock.mode = kb32->i.lock.mode;
 107                kb->i.lock.namelen = kb32->i.lock.namelen;
 108                kb->i.lock.flags = kb32->i.lock.flags;
 109                kb->i.lock.lkid = kb32->i.lock.lkid;
 110                kb->i.lock.parent = kb32->i.lock.parent;
 111                kb->i.lock.xid = kb32->i.lock.xid;
 112                kb->i.lock.timeout = kb32->i.lock.timeout;
 113                kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
 114                kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
 115                kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
 116                kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
 117                kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
 118                memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
 119                memcpy(kb->i.lock.name, kb32->i.lock.name, namelen);
 120        }
 121}
 122
 123static 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
 156static int lkb_is_endoflife(int mode, int status)
 157{
 158        switch (status) {
 159        case -DLM_EUNLOCK:
 160                return 1;
 161        case -DLM_ECANCEL:
 162        case -ETIMEDOUT:
 163        case -EDEADLK:
 164        case -EAGAIN:
 165                if (mode == DLM_LOCK_IV)
 166                        return 1;
 167                break;
 168        }
 169        return 0;
 170}
 171
 172/* we could possibly check if the cancel of an orphan has resulted in the lkb
 173   being removed and then remove that lkb from the orphans list and free it */
 174
 175void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode,
 176                      int status, uint32_t sbflags, uint64_t seq)
 177{
 178        struct dlm_ls *ls;
 179        struct dlm_user_args *ua;
 180        struct dlm_user_proc *proc;
 181        int rv;
 182
 183        if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
 184                return;
 185
 186        ls = lkb->lkb_resource->res_ls;
 187        mutex_lock(&ls->ls_clear_proc_locks);
 188
 189        /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
 190           can't be delivered.  For ORPHAN's, dlm_clear_proc_locks() freed
 191           lkb->ua so we can't try to use it.  This second check is necessary
 192           for cases where a completion ast is received for an operation that
 193           began before clear_proc_locks did its cancel/unlock. */
 194
 195        if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
 196                goto out;
 197
 198        DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
 199        ua = lkb->lkb_ua;
 200        proc = ua->proc;
 201
 202        if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL)
 203                goto out;
 204
 205        if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status))
 206                lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
 207
 208        spin_lock(&proc->asts_spin);
 209
 210        rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq);
 211        if (rv < 0) {
 212                spin_unlock(&proc->asts_spin);
 213                goto out;
 214        }
 215
 216        if (list_empty(&lkb->lkb_cb_list)) {
 217                kref_get(&lkb->lkb_ref);
 218                list_add_tail(&lkb->lkb_cb_list, &proc->asts);
 219                wake_up_interruptible(&proc->wait);
 220        }
 221        spin_unlock(&proc->asts_spin);
 222
 223        if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) {
 224                /* N.B. spin_lock locks_spin, not asts_spin */
 225                spin_lock(&proc->locks_spin);
 226                if (!list_empty(&lkb->lkb_ownqueue)) {
 227                        list_del_init(&lkb->lkb_ownqueue);
 228                        dlm_put_lkb(lkb);
 229                }
 230                spin_unlock(&proc->locks_spin);
 231        }
 232 out:
 233        mutex_unlock(&ls->ls_clear_proc_locks);
 234}
 235
 236static int device_user_lock(struct dlm_user_proc *proc,
 237                            struct dlm_lock_params *params)
 238{
 239        struct dlm_ls *ls;
 240        struct dlm_user_args *ua;
 241        uint32_t lkid;
 242        int error = -ENOMEM;
 243
 244        ls = dlm_find_lockspace_local(proc->lockspace);
 245        if (!ls)
 246                return -ENOENT;
 247
 248        if (!params->castaddr || !params->lksb) {
 249                error = -EINVAL;
 250                goto out;
 251        }
 252
 253        ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
 254        if (!ua)
 255                goto out;
 256        ua->proc = proc;
 257        ua->user_lksb = params->lksb;
 258        ua->castparam = params->castparam;
 259        ua->castaddr = params->castaddr;
 260        ua->bastparam = params->bastparam;
 261        ua->bastaddr = params->bastaddr;
 262        ua->xid = params->xid;
 263
 264        if (params->flags & DLM_LKF_CONVERT) {
 265                error = dlm_user_convert(ls, ua,
 266                                         params->mode, params->flags,
 267                                         params->lkid, params->lvb,
 268                                         (unsigned long) params->timeout);
 269        } else if (params->flags & DLM_LKF_ORPHAN) {
 270                error = dlm_user_adopt_orphan(ls, ua,
 271                                         params->mode, params->flags,
 272                                         params->name, params->namelen,
 273                                         (unsigned long) params->timeout,
 274                                         &lkid);
 275                if (!error)
 276                        error = lkid;
 277        } else {
 278                error = dlm_user_request(ls, ua,
 279                                         params->mode, params->flags,
 280                                         params->name, params->namelen,
 281                                         (unsigned long) params->timeout);
 282                if (!error)
 283                        error = ua->lksb.sb_lkid;
 284        }
 285 out:
 286        dlm_put_lockspace(ls);
 287        return error;
 288}
 289
 290static int device_user_unlock(struct dlm_user_proc *proc,
 291                              struct dlm_lock_params *params)
 292{
 293        struct dlm_ls *ls;
 294        struct dlm_user_args *ua;
 295        int error = -ENOMEM;
 296
 297        ls = dlm_find_lockspace_local(proc->lockspace);
 298        if (!ls)
 299                return -ENOENT;
 300
 301        ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
 302        if (!ua)
 303                goto out;
 304        ua->proc = proc;
 305        ua->user_lksb = params->lksb;
 306        ua->castparam = params->castparam;
 307        ua->castaddr = params->castaddr;
 308
 309        if (params->flags & DLM_LKF_CANCEL)
 310                error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
 311        else
 312                error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
 313                                        params->lvb);
 314 out:
 315        dlm_put_lockspace(ls);
 316        return error;
 317}
 318
 319static int device_user_deadlock(struct dlm_user_proc *proc,
 320                                struct dlm_lock_params *params)
 321{
 322        struct dlm_ls *ls;
 323        int error;
 324
 325        ls = dlm_find_lockspace_local(proc->lockspace);
 326        if (!ls)
 327                return -ENOENT;
 328
 329        error = dlm_user_deadlock(ls, params->flags, params->lkid);
 330
 331        dlm_put_lockspace(ls);
 332        return error;
 333}
 334
 335static int dlm_device_register(struct dlm_ls *ls, char *name)
 336{
 337        int error, len;
 338
 339        /* The device is already registered.  This happens when the
 340           lockspace is created multiple times from userspace. */
 341        if (ls->ls_device.name)
 342                return 0;
 343
 344        error = -ENOMEM;
 345        len = strlen(name) + strlen(name_prefix) + 2;
 346        ls->ls_device.name = kzalloc(len, GFP_NOFS);
 347        if (!ls->ls_device.name)
 348                goto fail;
 349
 350        snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
 351                 name);
 352        ls->ls_device.fops = &device_fops;
 353        ls->ls_device.minor = MISC_DYNAMIC_MINOR;
 354
 355        error = misc_register(&ls->ls_device);
 356        if (error) {
 357                kfree(ls->ls_device.name);
 358        }
 359fail:
 360        return error;
 361}
 362
 363int dlm_device_deregister(struct dlm_ls *ls)
 364{
 365        /* The device is not registered.  This happens when the lockspace
 366           was never used from userspace, or when device_create_lockspace()
 367           calls dlm_release_lockspace() after the register fails. */
 368        if (!ls->ls_device.name)
 369                return 0;
 370
 371        misc_deregister(&ls->ls_device);
 372        kfree(ls->ls_device.name);
 373        return 0;
 374}
 375
 376static int device_user_purge(struct dlm_user_proc *proc,
 377                             struct dlm_purge_params *params)
 378{
 379        struct dlm_ls *ls;
 380        int error;
 381
 382        ls = dlm_find_lockspace_local(proc->lockspace);
 383        if (!ls)
 384                return -ENOENT;
 385
 386        error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
 387
 388        dlm_put_lockspace(ls);
 389        return error;
 390}
 391
 392static int device_create_lockspace(struct dlm_lspace_params *params)
 393{
 394        dlm_lockspace_t *lockspace;
 395        struct dlm_ls *ls;
 396        int error;
 397
 398        if (!capable(CAP_SYS_ADMIN))
 399                return -EPERM;
 400
 401        error = dlm_new_lockspace(params->name, NULL, params->flags,
 402                                  DLM_USER_LVB_LEN, NULL, NULL, NULL,
 403                                  &lockspace);
 404        if (error)
 405                return error;
 406
 407        ls = dlm_find_lockspace_local(lockspace);
 408        if (!ls)
 409                return -ENOENT;
 410
 411        error = dlm_device_register(ls, params->name);
 412        dlm_put_lockspace(ls);
 413
 414        if (error)
 415                dlm_release_lockspace(lockspace, 0);
 416        else
 417                error = ls->ls_device.minor;
 418
 419        return error;
 420}
 421
 422static int device_remove_lockspace(struct dlm_lspace_params *params)
 423{
 424        dlm_lockspace_t *lockspace;
 425        struct dlm_ls *ls;
 426        int error, force = 0;
 427
 428        if (!capable(CAP_SYS_ADMIN))
 429                return -EPERM;
 430
 431        ls = dlm_find_lockspace_device(params->minor);
 432        if (!ls)
 433                return -ENOENT;
 434
 435        if (params->flags & DLM_USER_LSFLG_FORCEFREE)
 436                force = 2;
 437
 438        lockspace = ls->ls_local_handle;
 439        dlm_put_lockspace(ls);
 440
 441        /* The final dlm_release_lockspace waits for references to go to
 442           zero, so all processes will need to close their device for the
 443           ls before the release will proceed.  release also calls the
 444           device_deregister above.  Converting a positive return value
 445           from release to zero means that userspace won't know when its
 446           release was the final one, but it shouldn't need to know. */
 447
 448        error = dlm_release_lockspace(lockspace, force);
 449        if (error > 0)
 450                error = 0;
 451        return error;
 452}
 453
 454/* Check the user's version matches ours */
 455static int check_version(struct dlm_write_request *req)
 456{
 457        if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
 458            (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
 459             req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
 460
 461                printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
 462                       "user (%d.%d.%d) kernel (%d.%d.%d)\n",
 463                       current->comm,
 464                       task_pid_nr(current),
 465                       req->version[0],
 466                       req->version[1],
 467                       req->version[2],
 468                       DLM_DEVICE_VERSION_MAJOR,
 469                       DLM_DEVICE_VERSION_MINOR,
 470                       DLM_DEVICE_VERSION_PATCH);
 471                return -EINVAL;
 472        }
 473        return 0;
 474}
 475
 476/*
 477 * device_write
 478 *
 479 *   device_user_lock
 480 *     dlm_user_request -> request_lock
 481 *     dlm_user_convert -> convert_lock
 482 *
 483 *   device_user_unlock
 484 *     dlm_user_unlock -> unlock_lock
 485 *     dlm_user_cancel -> cancel_lock
 486 *
 487 *   device_create_lockspace
 488 *     dlm_new_lockspace
 489 *
 490 *   device_remove_lockspace
 491 *     dlm_release_lockspace
 492 */
 493
 494/* a write to a lockspace device is a lock or unlock request, a write
 495   to the control device is to create/remove a lockspace */
 496
 497static ssize_t device_write(struct file *file, const char __user *buf,
 498                            size_t count, loff_t *ppos)
 499{
 500        struct dlm_user_proc *proc = file->private_data;
 501        struct dlm_write_request *kbuf;
 502        int error;
 503
 504#ifdef CONFIG_COMPAT
 505        if (count < sizeof(struct dlm_write_request32))
 506#else
 507        if (count < sizeof(struct dlm_write_request))
 508#endif
 509                return -EINVAL;
 510
 511        /*
 512         * can't compare against COMPAT/dlm_write_request32 because
 513         * we don't yet know if is64bit is zero
 514         */
 515        if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
 516                return -EINVAL;
 517
 518        kbuf = memdup_user_nul(buf, count);
 519        if (IS_ERR(kbuf))
 520                return PTR_ERR(kbuf);
 521
 522        if (check_version(kbuf)) {
 523                error = -EBADE;
 524                goto out_free;
 525        }
 526
 527#ifdef CONFIG_COMPAT
 528        if (!kbuf->is64bit) {
 529                struct dlm_write_request32 *k32buf;
 530                int namelen = 0;
 531
 532                if (count > sizeof(struct dlm_write_request32))
 533                        namelen = count - sizeof(struct dlm_write_request32);
 534
 535                k32buf = (struct dlm_write_request32 *)kbuf;
 536
 537                /* add 1 after namelen so that the name string is terminated */
 538                kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
 539                               GFP_NOFS);
 540                if (!kbuf) {
 541                        kfree(k32buf);
 542                        return -ENOMEM;
 543                }
 544
 545                if (proc)
 546                        set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
 547
 548                compat_input(kbuf, k32buf, namelen);
 549                kfree(k32buf);
 550        }
 551#endif
 552
 553        /* do we really need this? can a write happen after a close? */
 554        if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
 555            (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
 556                error = -EINVAL;
 557                goto out_free;
 558        }
 559
 560        error = -EINVAL;
 561
 562        switch (kbuf->cmd)
 563        {
 564        case DLM_USER_LOCK:
 565                if (!proc) {
 566                        log_print("no locking on control device");
 567                        goto out_free;
 568                }
 569                error = device_user_lock(proc, &kbuf->i.lock);
 570                break;
 571
 572        case DLM_USER_UNLOCK:
 573                if (!proc) {
 574                        log_print("no locking on control device");
 575                        goto out_free;
 576                }
 577                error = device_user_unlock(proc, &kbuf->i.lock);
 578                break;
 579
 580        case DLM_USER_DEADLOCK:
 581                if (!proc) {
 582                        log_print("no locking on control device");
 583                        goto out_free;
 584                }
 585                error = device_user_deadlock(proc, &kbuf->i.lock);
 586                break;
 587
 588        case DLM_USER_CREATE_LOCKSPACE:
 589                if (proc) {
 590                        log_print("create/remove only on control device");
 591                        goto out_free;
 592                }
 593                error = device_create_lockspace(&kbuf->i.lspace);
 594                break;
 595
 596        case DLM_USER_REMOVE_LOCKSPACE:
 597                if (proc) {
 598                        log_print("create/remove only on control device");
 599                        goto out_free;
 600                }
 601                error = device_remove_lockspace(&kbuf->i.lspace);
 602                break;
 603
 604        case DLM_USER_PURGE:
 605                if (!proc) {
 606                        log_print("no locking on control device");
 607                        goto out_free;
 608                }
 609                error = device_user_purge(proc, &kbuf->i.purge);
 610                break;
 611
 612        default:
 613                log_print("Unknown command passed to DLM device : %d\n",
 614                          kbuf->cmd);
 615        }
 616
 617 out_free:
 618        kfree(kbuf);
 619        return error;
 620}
 621
 622/* Every process that opens the lockspace device has its own "proc" structure
 623   hanging off the open file that's used to keep track of locks owned by the
 624   process and asts that need to be delivered to the process. */
 625
 626static int device_open(struct inode *inode, struct file *file)
 627{
 628        struct dlm_user_proc *proc;
 629        struct dlm_ls *ls;
 630
 631        ls = dlm_find_lockspace_device(iminor(inode));
 632        if (!ls)
 633                return -ENOENT;
 634
 635        proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
 636        if (!proc) {
 637                dlm_put_lockspace(ls);
 638                return -ENOMEM;
 639        }
 640
 641        proc->lockspace = ls->ls_local_handle;
 642        INIT_LIST_HEAD(&proc->asts);
 643        INIT_LIST_HEAD(&proc->locks);
 644        INIT_LIST_HEAD(&proc->unlocking);
 645        spin_lock_init(&proc->asts_spin);
 646        spin_lock_init(&proc->locks_spin);
 647        init_waitqueue_head(&proc->wait);
 648        file->private_data = proc;
 649
 650        return 0;
 651}
 652
 653static int device_close(struct inode *inode, struct file *file)
 654{
 655        struct dlm_user_proc *proc = file->private_data;
 656        struct dlm_ls *ls;
 657
 658        ls = dlm_find_lockspace_local(proc->lockspace);
 659        if (!ls)
 660                return -ENOENT;
 661
 662        set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
 663
 664        dlm_clear_proc_locks(ls, proc);
 665
 666        /* at this point no more lkb's should exist for this lockspace,
 667           so there's no chance of dlm_user_add_ast() being called and
 668           looking for lkb->ua->proc */
 669
 670        kfree(proc);
 671        file->private_data = NULL;
 672
 673        dlm_put_lockspace(ls);
 674        dlm_put_lockspace(ls);  /* for the find in device_open() */
 675
 676        /* FIXME: AUTOFREE: if this ls is no longer used do
 677           device_remove_lockspace() */
 678
 679        return 0;
 680}
 681
 682static int copy_result_to_user(struct dlm_user_args *ua, int compat,
 683                               uint32_t flags, int mode, int copy_lvb,
 684                               char __user *buf, size_t count)
 685{
 686#ifdef CONFIG_COMPAT
 687        struct dlm_lock_result32 result32;
 688#endif
 689        struct dlm_lock_result result;
 690        void *resultptr;
 691        int error=0;
 692        int len;
 693        int struct_len;
 694
 695        memset(&result, 0, sizeof(struct dlm_lock_result));
 696        result.version[0] = DLM_DEVICE_VERSION_MAJOR;
 697        result.version[1] = DLM_DEVICE_VERSION_MINOR;
 698        result.version[2] = DLM_DEVICE_VERSION_PATCH;
 699        memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
 700        result.user_lksb = ua->user_lksb;
 701
 702        /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
 703           in a conversion unless the conversion is successful.  See code
 704           in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
 705           notes that a new blocking AST address and parameter are set even if
 706           the conversion fails, so maybe we should just do that. */
 707
 708        if (flags & DLM_CB_BAST) {
 709                result.user_astaddr = ua->bastaddr;
 710                result.user_astparam = ua->bastparam;
 711                result.bast_mode = mode;
 712        } else {
 713                result.user_astaddr = ua->castaddr;
 714                result.user_astparam = ua->castparam;
 715        }
 716
 717#ifdef CONFIG_COMPAT
 718        if (compat)
 719                len = sizeof(struct dlm_lock_result32);
 720        else
 721#endif
 722                len = sizeof(struct dlm_lock_result);
 723        struct_len = len;
 724
 725        /* copy lvb to userspace if there is one, it's been updated, and
 726           the user buffer has space for it */
 727
 728        if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
 729                if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
 730                                 DLM_USER_LVB_LEN)) {
 731                        error = -EFAULT;
 732                        goto out;
 733                }
 734
 735                result.lvb_offset = len;
 736                len += DLM_USER_LVB_LEN;
 737        }
 738
 739        result.length = len;
 740        resultptr = &result;
 741#ifdef CONFIG_COMPAT
 742        if (compat) {
 743                compat_output(&result, &result32);
 744                resultptr = &result32;
 745        }
 746#endif
 747
 748        if (copy_to_user(buf, resultptr, struct_len))
 749                error = -EFAULT;
 750        else
 751                error = len;
 752 out:
 753        return error;
 754}
 755
 756static 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
 772static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 773                           loff_t *ppos)
 774{
 775        struct dlm_user_proc *proc = file->private_data;
 776        struct dlm_lkb *lkb;
 777        DECLARE_WAITQUEUE(wait, current);
 778        struct dlm_callback cb;
 779        int rv, resid, copy_lvb = 0;
 780        int old_mode, new_mode;
 781
 782        if (count == sizeof(struct dlm_device_version)) {
 783                rv = copy_version_to_user(buf, count);
 784                return rv;
 785        }
 786
 787        if (!proc) {
 788                log_print("non-version read from control device %zu", count);
 789                return -EINVAL;
 790        }
 791
 792#ifdef CONFIG_COMPAT
 793        if (count < sizeof(struct dlm_lock_result32))
 794#else
 795        if (count < sizeof(struct dlm_lock_result))
 796#endif
 797                return -EINVAL;
 798
 799 try_another:
 800
 801        /* do we really need this? can a read happen after a close? */
 802        if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
 803                return -EINVAL;
 804
 805        spin_lock(&proc->asts_spin);
 806        if (list_empty(&proc->asts)) {
 807                if (file->f_flags & O_NONBLOCK) {
 808                        spin_unlock(&proc->asts_spin);
 809                        return -EAGAIN;
 810                }
 811
 812                add_wait_queue(&proc->wait, &wait);
 813
 814        repeat:
 815                set_current_state(TASK_INTERRUPTIBLE);
 816                if (list_empty(&proc->asts) && !signal_pending(current)) {
 817                        spin_unlock(&proc->asts_spin);
 818                        schedule();
 819                        spin_lock(&proc->asts_spin);
 820                        goto repeat;
 821                }
 822                set_current_state(TASK_RUNNING);
 823                remove_wait_queue(&proc->wait, &wait);
 824
 825                if (signal_pending(current)) {
 826                        spin_unlock(&proc->asts_spin);
 827                        return -ERESTARTSYS;
 828                }
 829        }
 830
 831        /* if we empty lkb_callbacks, we don't want to unlock the spinlock
 832           without removing lkb_cb_list; so empty lkb_cb_list is always
 833           consistent with empty lkb_callbacks */
 834
 835        lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
 836
 837        /* rem_lkb_callback sets a new lkb_last_cast */
 838        old_mode = lkb->lkb_last_cast.mode;
 839
 840        rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
 841        if (rv < 0) {
 842                /* this shouldn't happen; lkb should have been removed from
 843                   list when resid was zero */
 844                log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
 845                list_del_init(&lkb->lkb_cb_list);
 846                spin_unlock(&proc->asts_spin);
 847                /* removes ref for proc->asts, may cause lkb to be freed */
 848                dlm_put_lkb(lkb);
 849                goto try_another;
 850        }
 851        if (!resid)
 852                list_del_init(&lkb->lkb_cb_list);
 853        spin_unlock(&proc->asts_spin);
 854
 855        if (cb.flags & DLM_CB_SKIP) {
 856                /* removes ref for proc->asts, may cause lkb to be freed */
 857                if (!resid)
 858                        dlm_put_lkb(lkb);
 859                goto try_another;
 860        }
 861
 862        if (cb.flags & DLM_CB_CAST) {
 863                new_mode = cb.mode;
 864
 865                if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
 866                    dlm_lvb_operations[old_mode + 1][new_mode + 1])
 867                        copy_lvb = 1;
 868
 869                lkb->lkb_lksb->sb_status = cb.sb_status;
 870                lkb->lkb_lksb->sb_flags = cb.sb_flags;
 871        }
 872
 873        rv = copy_result_to_user(lkb->lkb_ua,
 874                                 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
 875                                 cb.flags, cb.mode, copy_lvb, buf, count);
 876
 877        /* removes ref for proc->asts, may cause lkb to be freed */
 878        if (!resid)
 879                dlm_put_lkb(lkb);
 880
 881        return rv;
 882}
 883
 884static unsigned int device_poll(struct file *file, poll_table *wait)
 885{
 886        struct dlm_user_proc *proc = file->private_data;
 887
 888        poll_wait(file, &proc->wait, wait);
 889
 890        spin_lock(&proc->asts_spin);
 891        if (!list_empty(&proc->asts)) {
 892                spin_unlock(&proc->asts_spin);
 893                return POLLIN | POLLRDNORM;
 894        }
 895        spin_unlock(&proc->asts_spin);
 896        return 0;
 897}
 898
 899int dlm_user_daemon_available(void)
 900{
 901        /* dlm_controld hasn't started (or, has started, but not
 902           properly populated configfs) */
 903
 904        if (!dlm_our_nodeid())
 905                return 0;
 906
 907        /* This is to deal with versions of dlm_controld that don't
 908           know about the monitor device.  We assume that if the
 909           dlm_controld was started (above), but the monitor device
 910           was never opened, that it's an old version.  dlm_controld
 911           should open the monitor device before populating configfs. */
 912
 913        if (dlm_monitor_unused)
 914                return 1;
 915
 916        return atomic_read(&dlm_monitor_opened) ? 1 : 0;
 917}
 918
 919static int ctl_device_open(struct inode *inode, struct file *file)
 920{
 921        file->private_data = NULL;
 922        return 0;
 923}
 924
 925static int ctl_device_close(struct inode *inode, struct file *file)
 926{
 927        return 0;
 928}
 929
 930static int monitor_device_open(struct inode *inode, struct file *file)
 931{
 932        atomic_inc(&dlm_monitor_opened);
 933        dlm_monitor_unused = 0;
 934        return 0;
 935}
 936
 937static int monitor_device_close(struct inode *inode, struct file *file)
 938{
 939        if (atomic_dec_and_test(&dlm_monitor_opened))
 940                dlm_stop_lockspaces();
 941        return 0;
 942}
 943
 944static const struct file_operations device_fops = {
 945        .open    = device_open,
 946        .release = device_close,
 947        .read    = device_read,
 948        .write   = device_write,
 949        .poll    = device_poll,
 950        .owner   = THIS_MODULE,
 951        .llseek  = noop_llseek,
 952};
 953
 954static const struct file_operations ctl_device_fops = {
 955        .open    = ctl_device_open,
 956        .release = ctl_device_close,
 957        .read    = device_read,
 958        .write   = device_write,
 959        .owner   = THIS_MODULE,
 960        .llseek  = noop_llseek,
 961};
 962
 963static struct miscdevice ctl_device = {
 964        .name  = "dlm-control",
 965        .fops  = &ctl_device_fops,
 966        .minor = MISC_DYNAMIC_MINOR,
 967};
 968
 969static const struct file_operations monitor_device_fops = {
 970        .open    = monitor_device_open,
 971        .release = monitor_device_close,
 972        .owner   = THIS_MODULE,
 973        .llseek  = noop_llseek,
 974};
 975
 976static struct miscdevice monitor_device = {
 977        .name  = "dlm-monitor",
 978        .fops  = &monitor_device_fops,
 979        .minor = MISC_DYNAMIC_MINOR,
 980};
 981
 982int __init dlm_user_init(void)
 983{
 984        int error;
 985
 986        atomic_set(&dlm_monitor_opened, 0);
 987
 988        error = misc_register(&ctl_device);
 989        if (error) {
 990                log_print("misc_register failed for control device");
 991                goto out;
 992        }
 993
 994        error = misc_register(&monitor_device);
 995        if (error) {
 996                log_print("misc_register failed for monitor device");
 997                misc_deregister(&ctl_device);
 998        }
 999 out:
1000        return error;
1001}
1002
1003void dlm_user_exit(void)
1004{
1005        misc_deregister(&ctl_device);
1006        misc_deregister(&monitor_device);
1007}
1008
1009