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        int error = -ENOMEM;
 242
 243        ls = dlm_find_lockspace_local(proc->lockspace);
 244        if (!ls)
 245                return -ENOENT;
 246
 247        if (!params->castaddr || !params->lksb) {
 248                error = -EINVAL;
 249                goto out;
 250        }
 251
 252        ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
 253        if (!ua)
 254                goto out;
 255        ua->proc = proc;
 256        ua->user_lksb = params->lksb;
 257        ua->castparam = params->castparam;
 258        ua->castaddr = params->castaddr;
 259        ua->bastparam = params->bastparam;
 260        ua->bastaddr = params->bastaddr;
 261        ua->xid = params->xid;
 262
 263        if (params->flags & DLM_LKF_CONVERT)
 264                error = dlm_user_convert(ls, ua,
 265                                         params->mode, params->flags,
 266                                         params->lkid, params->lvb,
 267                                         (unsigned long) params->timeout);
 268        else {
 269                error = dlm_user_request(ls, ua,
 270                                         params->mode, params->flags,
 271                                         params->name, params->namelen,
 272                                         (unsigned long) params->timeout);
 273                if (!error)
 274                        error = ua->lksb.sb_lkid;
 275        }
 276 out:
 277        dlm_put_lockspace(ls);
 278        return error;
 279}
 280
 281static int device_user_unlock(struct dlm_user_proc *proc,
 282                              struct dlm_lock_params *params)
 283{
 284        struct dlm_ls *ls;
 285        struct dlm_user_args *ua;
 286        int error = -ENOMEM;
 287
 288        ls = dlm_find_lockspace_local(proc->lockspace);
 289        if (!ls)
 290                return -ENOENT;
 291
 292        ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
 293        if (!ua)
 294                goto out;
 295        ua->proc = proc;
 296        ua->user_lksb = params->lksb;
 297        ua->castparam = params->castparam;
 298        ua->castaddr = params->castaddr;
 299
 300        if (params->flags & DLM_LKF_CANCEL)
 301                error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
 302        else
 303                error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
 304                                        params->lvb);
 305 out:
 306        dlm_put_lockspace(ls);
 307        return error;
 308}
 309
 310static int device_user_deadlock(struct dlm_user_proc *proc,
 311                                struct dlm_lock_params *params)
 312{
 313        struct dlm_ls *ls;
 314        int error;
 315
 316        ls = dlm_find_lockspace_local(proc->lockspace);
 317        if (!ls)
 318                return -ENOENT;
 319
 320        error = dlm_user_deadlock(ls, params->flags, params->lkid);
 321
 322        dlm_put_lockspace(ls);
 323        return error;
 324}
 325
 326static int dlm_device_register(struct dlm_ls *ls, char *name)
 327{
 328        int error, len;
 329
 330        /* The device is already registered.  This happens when the
 331           lockspace is created multiple times from userspace. */
 332        if (ls->ls_device.name)
 333                return 0;
 334
 335        error = -ENOMEM;
 336        len = strlen(name) + strlen(name_prefix) + 2;
 337        ls->ls_device.name = kzalloc(len, GFP_NOFS);
 338        if (!ls->ls_device.name)
 339                goto fail;
 340
 341        snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
 342                 name);
 343        ls->ls_device.fops = &device_fops;
 344        ls->ls_device.minor = MISC_DYNAMIC_MINOR;
 345
 346        error = misc_register(&ls->ls_device);
 347        if (error) {
 348                kfree(ls->ls_device.name);
 349        }
 350fail:
 351        return error;
 352}
 353
 354int dlm_device_deregister(struct dlm_ls *ls)
 355{
 356        int error;
 357
 358        /* The device is not registered.  This happens when the lockspace
 359           was never used from userspace, or when device_create_lockspace()
 360           calls dlm_release_lockspace() after the register fails. */
 361        if (!ls->ls_device.name)
 362                return 0;
 363
 364        error = misc_deregister(&ls->ls_device);
 365        if (!error)
 366                kfree(ls->ls_device.name);
 367        return error;
 368}
 369
 370static int device_user_purge(struct dlm_user_proc *proc,
 371                             struct dlm_purge_params *params)
 372{
 373        struct dlm_ls *ls;
 374        int error;
 375
 376        ls = dlm_find_lockspace_local(proc->lockspace);
 377        if (!ls)
 378                return -ENOENT;
 379
 380        error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
 381
 382        dlm_put_lockspace(ls);
 383        return error;
 384}
 385
 386static int device_create_lockspace(struct dlm_lspace_params *params)
 387{
 388        dlm_lockspace_t *lockspace;
 389        struct dlm_ls *ls;
 390        int error;
 391
 392        if (!capable(CAP_SYS_ADMIN))
 393                return -EPERM;
 394
 395        error = dlm_new_lockspace(params->name, NULL, params->flags,
 396                                  DLM_USER_LVB_LEN, NULL, NULL, NULL,
 397                                  &lockspace);
 398        if (error)
 399                return error;
 400
 401        ls = dlm_find_lockspace_local(lockspace);
 402        if (!ls)
 403                return -ENOENT;
 404
 405        error = dlm_device_register(ls, params->name);
 406        dlm_put_lockspace(ls);
 407
 408        if (error)
 409                dlm_release_lockspace(lockspace, 0);
 410        else
 411                error = ls->ls_device.minor;
 412
 413        return error;
 414}
 415
 416static int device_remove_lockspace(struct dlm_lspace_params *params)
 417{
 418        dlm_lockspace_t *lockspace;
 419        struct dlm_ls *ls;
 420        int error, force = 0;
 421
 422        if (!capable(CAP_SYS_ADMIN))
 423                return -EPERM;
 424
 425        ls = dlm_find_lockspace_device(params->minor);
 426        if (!ls)
 427                return -ENOENT;
 428
 429        if (params->flags & DLM_USER_LSFLG_FORCEFREE)
 430                force = 2;
 431
 432        lockspace = ls->ls_local_handle;
 433        dlm_put_lockspace(ls);
 434
 435        /* The final dlm_release_lockspace waits for references to go to
 436           zero, so all processes will need to close their device for the
 437           ls before the release will proceed.  release also calls the
 438           device_deregister above.  Converting a positive return value
 439           from release to zero means that userspace won't know when its
 440           release was the final one, but it shouldn't need to know. */
 441
 442        error = dlm_release_lockspace(lockspace, force);
 443        if (error > 0)
 444                error = 0;
 445        return error;
 446}
 447
 448/* Check the user's version matches ours */
 449static int check_version(struct dlm_write_request *req)
 450{
 451        if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
 452            (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
 453             req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
 454
 455                printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
 456                       "user (%d.%d.%d) kernel (%d.%d.%d)\n",
 457                       current->comm,
 458                       task_pid_nr(current),
 459                       req->version[0],
 460                       req->version[1],
 461                       req->version[2],
 462                       DLM_DEVICE_VERSION_MAJOR,
 463                       DLM_DEVICE_VERSION_MINOR,
 464                       DLM_DEVICE_VERSION_PATCH);
 465                return -EINVAL;
 466        }
 467        return 0;
 468}
 469
 470/*
 471 * device_write
 472 *
 473 *   device_user_lock
 474 *     dlm_user_request -> request_lock
 475 *     dlm_user_convert -> convert_lock
 476 *
 477 *   device_user_unlock
 478 *     dlm_user_unlock -> unlock_lock
 479 *     dlm_user_cancel -> cancel_lock
 480 *
 481 *   device_create_lockspace
 482 *     dlm_new_lockspace
 483 *
 484 *   device_remove_lockspace
 485 *     dlm_release_lockspace
 486 */
 487
 488/* a write to a lockspace device is a lock or unlock request, a write
 489   to the control device is to create/remove a lockspace */
 490
 491static ssize_t device_write(struct file *file, const char __user *buf,
 492                            size_t count, loff_t *ppos)
 493{
 494        struct dlm_user_proc *proc = file->private_data;
 495        struct dlm_write_request *kbuf;
 496        sigset_t tmpsig, allsigs;
 497        int error;
 498
 499#ifdef CONFIG_COMPAT
 500        if (count < sizeof(struct dlm_write_request32))
 501#else
 502        if (count < sizeof(struct dlm_write_request))
 503#endif
 504                return -EINVAL;
 505
 506        kbuf = kzalloc(count + 1, GFP_NOFS);
 507        if (!kbuf)
 508                return -ENOMEM;
 509
 510        if (copy_from_user(kbuf, buf, count)) {
 511                error = -EFAULT;
 512                goto out_free;
 513        }
 514
 515        if (check_version(kbuf)) {
 516                error = -EBADE;
 517                goto out_free;
 518        }
 519
 520#ifdef CONFIG_COMPAT
 521        if (!kbuf->is64bit) {
 522                struct dlm_write_request32 *k32buf;
 523                int namelen = 0;
 524
 525                if (count > sizeof(struct dlm_write_request32))
 526                        namelen = count - sizeof(struct dlm_write_request32);
 527
 528                k32buf = (struct dlm_write_request32 *)kbuf;
 529
 530                /* add 1 after namelen so that the name string is terminated */
 531                kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
 532                               GFP_NOFS);
 533                if (!kbuf) {
 534                        kfree(k32buf);
 535                        return -ENOMEM;
 536                }
 537
 538                if (proc)
 539                        set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
 540
 541                compat_input(kbuf, k32buf, namelen);
 542                kfree(k32buf);
 543        }
 544#endif
 545
 546        /* do we really need this? can a write happen after a close? */
 547        if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
 548            (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
 549                error = -EINVAL;
 550                goto out_free;
 551        }
 552
 553        sigfillset(&allsigs);
 554        sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
 555
 556        error = -EINVAL;
 557
 558        switch (kbuf->cmd)
 559        {
 560        case DLM_USER_LOCK:
 561                if (!proc) {
 562                        log_print("no locking on control device");
 563                        goto out_sig;
 564                }
 565                error = device_user_lock(proc, &kbuf->i.lock);
 566                break;
 567
 568        case DLM_USER_UNLOCK:
 569                if (!proc) {
 570                        log_print("no locking on control device");
 571                        goto out_sig;
 572                }
 573                error = device_user_unlock(proc, &kbuf->i.lock);
 574                break;
 575
 576        case DLM_USER_DEADLOCK:
 577                if (!proc) {
 578                        log_print("no locking on control device");
 579                        goto out_sig;
 580                }
 581                error = device_user_deadlock(proc, &kbuf->i.lock);
 582                break;
 583
 584        case DLM_USER_CREATE_LOCKSPACE:
 585                if (proc) {
 586                        log_print("create/remove only on control device");
 587                        goto out_sig;
 588                }
 589                error = device_create_lockspace(&kbuf->i.lspace);
 590                break;
 591
 592        case DLM_USER_REMOVE_LOCKSPACE:
 593                if (proc) {
 594                        log_print("create/remove only on control device");
 595                        goto out_sig;
 596                }
 597                error = device_remove_lockspace(&kbuf->i.lspace);
 598                break;
 599
 600        case DLM_USER_PURGE:
 601                if (!proc) {
 602                        log_print("no locking on control device");
 603                        goto out_sig;
 604                }
 605                error = device_user_purge(proc, &kbuf->i.purge);
 606                break;
 607
 608        default:
 609                log_print("Unknown command passed to DLM device : %d\n",
 610                          kbuf->cmd);
 611        }
 612
 613 out_sig:
 614        sigprocmask(SIG_SETMASK, &tmpsig, NULL);
 615 out_free:
 616        kfree(kbuf);
 617        return error;
 618}
 619
 620/* Every process that opens the lockspace device has its own "proc" structure
 621   hanging off the open file that's used to keep track of locks owned by the
 622   process and asts that need to be delivered to the process. */
 623
 624static int device_open(struct inode *inode, struct file *file)
 625{
 626        struct dlm_user_proc *proc;
 627        struct dlm_ls *ls;
 628
 629        ls = dlm_find_lockspace_device(iminor(inode));
 630        if (!ls)
 631                return -ENOENT;
 632
 633        proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
 634        if (!proc) {
 635                dlm_put_lockspace(ls);
 636                return -ENOMEM;
 637        }
 638
 639        proc->lockspace = ls->ls_local_handle;
 640        INIT_LIST_HEAD(&proc->asts);
 641        INIT_LIST_HEAD(&proc->locks);
 642        INIT_LIST_HEAD(&proc->unlocking);
 643        spin_lock_init(&proc->asts_spin);
 644        spin_lock_init(&proc->locks_spin);
 645        init_waitqueue_head(&proc->wait);
 646        file->private_data = proc;
 647
 648        return 0;
 649}
 650
 651static int device_close(struct inode *inode, struct file *file)
 652{
 653        struct dlm_user_proc *proc = file->private_data;
 654        struct dlm_ls *ls;
 655        sigset_t tmpsig, allsigs;
 656
 657        ls = dlm_find_lockspace_local(proc->lockspace);
 658        if (!ls)
 659                return -ENOENT;
 660
 661        sigfillset(&allsigs);
 662        sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
 663
 664        set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
 665
 666        dlm_clear_proc_locks(ls, proc);
 667
 668        /* at this point no more lkb's should exist for this lockspace,
 669           so there's no chance of dlm_user_add_ast() being called and
 670           looking for lkb->ua->proc */
 671
 672        kfree(proc);
 673        file->private_data = NULL;
 674
 675        dlm_put_lockspace(ls);
 676        dlm_put_lockspace(ls);  /* for the find in device_open() */
 677
 678        /* FIXME: AUTOFREE: if this ls is no longer used do
 679           device_remove_lockspace() */
 680
 681        sigprocmask(SIG_SETMASK, &tmpsig, NULL);
 682        recalc_sigpending();
 683
 684        return 0;
 685}
 686
 687static int copy_result_to_user(struct dlm_user_args *ua, int compat,
 688                               uint32_t flags, int mode, int copy_lvb,
 689                               char __user *buf, size_t count)
 690{
 691#ifdef CONFIG_COMPAT
 692        struct dlm_lock_result32 result32;
 693#endif
 694        struct dlm_lock_result result;
 695        void *resultptr;
 696        int error=0;
 697        int len;
 698        int struct_len;
 699
 700        memset(&result, 0, sizeof(struct dlm_lock_result));
 701        result.version[0] = DLM_DEVICE_VERSION_MAJOR;
 702        result.version[1] = DLM_DEVICE_VERSION_MINOR;
 703        result.version[2] = DLM_DEVICE_VERSION_PATCH;
 704        memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
 705        result.user_lksb = ua->user_lksb;
 706
 707        /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
 708           in a conversion unless the conversion is successful.  See code
 709           in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
 710           notes that a new blocking AST address and parameter are set even if
 711           the conversion fails, so maybe we should just do that. */
 712
 713        if (flags & DLM_CB_BAST) {
 714                result.user_astaddr = ua->bastaddr;
 715                result.user_astparam = ua->bastparam;
 716                result.bast_mode = mode;
 717        } else {
 718                result.user_astaddr = ua->castaddr;
 719                result.user_astparam = ua->castparam;
 720        }
 721
 722#ifdef CONFIG_COMPAT
 723        if (compat)
 724                len = sizeof(struct dlm_lock_result32);
 725        else
 726#endif
 727                len = sizeof(struct dlm_lock_result);
 728        struct_len = len;
 729
 730        /* copy lvb to userspace if there is one, it's been updated, and
 731           the user buffer has space for it */
 732
 733        if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
 734                if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
 735                                 DLM_USER_LVB_LEN)) {
 736                        error = -EFAULT;
 737                        goto out;
 738                }
 739
 740                result.lvb_offset = len;
 741                len += DLM_USER_LVB_LEN;
 742        }
 743
 744        result.length = len;
 745        resultptr = &result;
 746#ifdef CONFIG_COMPAT
 747        if (compat) {
 748                compat_output(&result, &result32);
 749                resultptr = &result32;
 750        }
 751#endif
 752
 753        if (copy_to_user(buf, resultptr, struct_len))
 754                error = -EFAULT;
 755        else
 756                error = len;
 757 out:
 758        return error;
 759}
 760
 761static int copy_version_to_user(char __user *buf, size_t count)
 762{
 763        struct dlm_device_version ver;
 764
 765        memset(&ver, 0, sizeof(struct dlm_device_version));
 766        ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
 767        ver.version[1] = DLM_DEVICE_VERSION_MINOR;
 768        ver.version[2] = DLM_DEVICE_VERSION_PATCH;
 769
 770        if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
 771                return -EFAULT;
 772        return sizeof(struct dlm_device_version);
 773}
 774
 775/* a read returns a single ast described in a struct dlm_lock_result */
 776
 777static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 778                           loff_t *ppos)
 779{
 780        struct dlm_user_proc *proc = file->private_data;
 781        struct dlm_lkb *lkb;
 782        DECLARE_WAITQUEUE(wait, current);
 783        struct dlm_callback cb;
 784        int rv, resid, copy_lvb = 0;
 785
 786        if (count == sizeof(struct dlm_device_version)) {
 787                rv = copy_version_to_user(buf, count);
 788                return rv;
 789        }
 790
 791        if (!proc) {
 792                log_print("non-version read from control device %zu", count);
 793                return -EINVAL;
 794        }
 795
 796#ifdef CONFIG_COMPAT
 797        if (count < sizeof(struct dlm_lock_result32))
 798#else
 799        if (count < sizeof(struct dlm_lock_result))
 800#endif
 801                return -EINVAL;
 802
 803 try_another:
 804
 805        /* do we really need this? can a read happen after a close? */
 806        if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
 807                return -EINVAL;
 808
 809        spin_lock(&proc->asts_spin);
 810        if (list_empty(&proc->asts)) {
 811                if (file->f_flags & O_NONBLOCK) {
 812                        spin_unlock(&proc->asts_spin);
 813                        return -EAGAIN;
 814                }
 815
 816                add_wait_queue(&proc->wait, &wait);
 817
 818        repeat:
 819                set_current_state(TASK_INTERRUPTIBLE);
 820                if (list_empty(&proc->asts) && !signal_pending(current)) {
 821                        spin_unlock(&proc->asts_spin);
 822                        schedule();
 823                        spin_lock(&proc->asts_spin);
 824                        goto repeat;
 825                }
 826                set_current_state(TASK_RUNNING);
 827                remove_wait_queue(&proc->wait, &wait);
 828
 829                if (signal_pending(current)) {
 830                        spin_unlock(&proc->asts_spin);
 831                        return -ERESTARTSYS;
 832                }
 833        }
 834
 835        /* if we empty lkb_callbacks, we don't want to unlock the spinlock
 836           without removing lkb_cb_list; so empty lkb_cb_list is always
 837           consistent with empty lkb_callbacks */
 838
 839        lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
 840
 841        rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
 842        if (rv < 0) {
 843                /* this shouldn't happen; lkb should have been removed from
 844                   list when resid was zero */
 845                log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
 846                list_del_init(&lkb->lkb_cb_list);
 847                spin_unlock(&proc->asts_spin);
 848                /* removes ref for proc->asts, may cause lkb to be freed */
 849                dlm_put_lkb(lkb);
 850                goto try_another;
 851        }
 852        if (!resid)
 853                list_del_init(&lkb->lkb_cb_list);
 854        spin_unlock(&proc->asts_spin);
 855
 856        if (cb.flags & DLM_CB_SKIP) {
 857                /* removes ref for proc->asts, may cause lkb to be freed */
 858                if (!resid)
 859                        dlm_put_lkb(lkb);
 860                goto try_another;
 861        }
 862
 863        if (cb.flags & DLM_CB_CAST) {
 864                int old_mode, new_mode;
 865
 866                old_mode = lkb->lkb_last_cast.mode;
 867                new_mode = cb.mode;
 868
 869                if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
 870                    dlm_lvb_operations[old_mode + 1][new_mode + 1])
 871                        copy_lvb = 1;
 872
 873                lkb->lkb_lksb->sb_status = cb.sb_status;
 874                lkb->lkb_lksb->sb_flags = cb.sb_flags;
 875        }
 876
 877        rv = copy_result_to_user(lkb->lkb_ua,
 878                                 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
 879                                 cb.flags, cb.mode, copy_lvb, buf, count);
 880
 881        /* removes ref for proc->asts, may cause lkb to be freed */
 882        if (!resid)
 883                dlm_put_lkb(lkb);
 884
 885        return rv;
 886}
 887
 888static unsigned int device_poll(struct file *file, poll_table *wait)
 889{
 890        struct dlm_user_proc *proc = file->private_data;
 891
 892        poll_wait(file, &proc->wait, wait);
 893
 894        spin_lock(&proc->asts_spin);
 895        if (!list_empty(&proc->asts)) {
 896                spin_unlock(&proc->asts_spin);
 897                return POLLIN | POLLRDNORM;
 898        }
 899        spin_unlock(&proc->asts_spin);
 900        return 0;
 901}
 902
 903int dlm_user_daemon_available(void)
 904{
 905        /* dlm_controld hasn't started (or, has started, but not
 906           properly populated configfs) */
 907
 908        if (!dlm_our_nodeid())
 909                return 0;
 910
 911        /* This is to deal with versions of dlm_controld that don't
 912           know about the monitor device.  We assume that if the
 913           dlm_controld was started (above), but the monitor device
 914           was never opened, that it's an old version.  dlm_controld
 915           should open the monitor device before populating configfs. */
 916
 917        if (dlm_monitor_unused)
 918                return 1;
 919
 920        return atomic_read(&dlm_monitor_opened) ? 1 : 0;
 921}
 922
 923static int ctl_device_open(struct inode *inode, struct file *file)
 924{
 925        file->private_data = NULL;
 926        return 0;
 927}
 928
 929static int ctl_device_close(struct inode *inode, struct file *file)
 930{
 931        return 0;
 932}
 933
 934static int monitor_device_open(struct inode *inode, struct file *file)
 935{
 936        atomic_inc(&dlm_monitor_opened);
 937        dlm_monitor_unused = 0;
 938        return 0;
 939}
 940
 941static int monitor_device_close(struct inode *inode, struct file *file)
 942{
 943        if (atomic_dec_and_test(&dlm_monitor_opened))
 944                dlm_stop_lockspaces();
 945        return 0;
 946}
 947
 948static const struct file_operations device_fops = {
 949        .open    = device_open,
 950        .release = device_close,
 951        .read    = device_read,
 952        .write   = device_write,
 953        .poll    = device_poll,
 954        .owner   = THIS_MODULE,
 955        .llseek  = noop_llseek,
 956};
 957
 958static const struct file_operations ctl_device_fops = {
 959        .open    = ctl_device_open,
 960        .release = ctl_device_close,
 961        .read    = device_read,
 962        .write   = device_write,
 963        .owner   = THIS_MODULE,
 964        .llseek  = noop_llseek,
 965};
 966
 967static struct miscdevice ctl_device = {
 968        .name  = "dlm-control",
 969        .fops  = &ctl_device_fops,
 970        .minor = MISC_DYNAMIC_MINOR,
 971};
 972
 973static const struct file_operations monitor_device_fops = {
 974        .open    = monitor_device_open,
 975        .release = monitor_device_close,
 976        .owner   = THIS_MODULE,
 977        .llseek  = noop_llseek,
 978};
 979
 980static struct miscdevice monitor_device = {
 981        .name  = "dlm-monitor",
 982        .fops  = &monitor_device_fops,
 983        .minor = MISC_DYNAMIC_MINOR,
 984};
 985
 986int __init dlm_user_init(void)
 987{
 988        int error;
 989
 990        atomic_set(&dlm_monitor_opened, 0);
 991
 992        error = misc_register(&ctl_device);
 993        if (error) {
 994                log_print("misc_register failed for control device");
 995                goto out;
 996        }
 997
 998        error = misc_register(&monitor_device);
 999        if (error) {
1000                log_print("misc_register failed for monitor device");
1001                misc_deregister(&ctl_device);
1002        }
1003 out:
1004        return error;
1005}
1006
1007void dlm_user_exit(void)
1008{
1009        misc_deregister(&ctl_device);
1010        misc_deregister(&monitor_device);
1011}
1012
1013
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