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#ifdef CONFIG_COMPAT
 507        if (count > sizeof(struct dlm_write_request32) + DLM_RESNAME_MAXLEN)
 508#else
 509        if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
 510#endif
 511                return -EINVAL;
 512
 513        kbuf = kzalloc(count + 1, GFP_NOFS);
 514        if (!kbuf)
 515                return -ENOMEM;
 516
 517        if (copy_from_user(kbuf, buf, count)) {
 518                error = -EFAULT;
 519                goto out_free;
 520        }
 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        sigfillset(&allsigs);
 561        sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
 562
 563        error = -EINVAL;
 564
 565        switch (kbuf->cmd)
 566        {
 567        case DLM_USER_LOCK:
 568                if (!proc) {
 569                        log_print("no locking on control device");
 570                        goto out_sig;
 571                }
 572                error = device_user_lock(proc, &kbuf->i.lock);
 573                break;
 574
 575        case DLM_USER_UNLOCK:
 576                if (!proc) {
 577                        log_print("no locking on control device");
 578                        goto out_sig;
 579                }
 580                error = device_user_unlock(proc, &kbuf->i.lock);
 581                break;
 582
 583        case DLM_USER_DEADLOCK:
 584                if (!proc) {
 585                        log_print("no locking on control device");
 586                        goto out_sig;
 587                }
 588                error = device_user_deadlock(proc, &kbuf->i.lock);
 589                break;
 590
 591        case DLM_USER_CREATE_LOCKSPACE:
 592                if (proc) {
 593                        log_print("create/remove only on control device");
 594                        goto out_sig;
 595                }
 596                error = device_create_lockspace(&kbuf->i.lspace);
 597                break;
 598
 599        case DLM_USER_REMOVE_LOCKSPACE:
 600                if (proc) {
 601                        log_print("create/remove only on control device");
 602                        goto out_sig;
 603                }
 604                error = device_remove_lockspace(&kbuf->i.lspace);
 605                break;
 606
 607        case DLM_USER_PURGE:
 608                if (!proc) {
 609                        log_print("no locking on control device");
 610                        goto out_sig;
 611                }
 612                error = device_user_purge(proc, &kbuf->i.purge);
 613                break;
 614
 615        default:
 616                log_print("Unknown command passed to DLM device : %d\n",
 617                          kbuf->cmd);
 618        }
 619
 620 out_sig:
 621        sigprocmask(SIG_SETMASK, &tmpsig, NULL);
 622 out_free:
 623        kfree(kbuf);
 624        return error;
 625}
 626
 627/* Every process that opens the lockspace device has its own "proc" structure
 628   hanging off the open file that's used to keep track of locks owned by the
 629   process and asts that need to be delivered to the process. */
 630
 631static int device_open(struct inode *inode, struct file *file)
 632{
 633        struct dlm_user_proc *proc;
 634        struct dlm_ls *ls;
 635
 636        ls = dlm_find_lockspace_device(iminor(inode));
 637        if (!ls)
 638                return -ENOENT;
 639
 640        proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
 641        if (!proc) {
 642                dlm_put_lockspace(ls);
 643                return -ENOMEM;
 644        }
 645
 646        proc->lockspace = ls->ls_local_handle;
 647        INIT_LIST_HEAD(&proc->asts);
 648        INIT_LIST_HEAD(&proc->locks);
 649        INIT_LIST_HEAD(&proc->unlocking);
 650        spin_lock_init(&proc->asts_spin);
 651        spin_lock_init(&proc->locks_spin);
 652        init_waitqueue_head(&proc->wait);
 653        file->private_data = proc;
 654
 655        return 0;
 656}
 657
 658static int device_close(struct inode *inode, struct file *file)
 659{
 660        struct dlm_user_proc *proc = file->private_data;
 661        struct dlm_ls *ls;
 662        sigset_t tmpsig, allsigs;
 663
 664        ls = dlm_find_lockspace_local(proc->lockspace);
 665        if (!ls)
 666                return -ENOENT;
 667
 668        sigfillset(&allsigs);
 669        sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
 670
 671        set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
 672
 673        dlm_clear_proc_locks(ls, proc);
 674
 675        /* at this point no more lkb's should exist for this lockspace,
 676           so there's no chance of dlm_user_add_ast() being called and
 677           looking for lkb->ua->proc */
 678
 679        kfree(proc);
 680        file->private_data = NULL;
 681
 682        dlm_put_lockspace(ls);
 683        dlm_put_lockspace(ls);  /* for the find in device_open() */
 684
 685        /* FIXME: AUTOFREE: if this ls is no longer used do
 686           device_remove_lockspace() */
 687
 688        sigprocmask(SIG_SETMASK, &tmpsig, NULL);
 689        recalc_sigpending();
 690
 691        return 0;
 692}
 693
 694static int copy_result_to_user(struct dlm_user_args *ua, int compat,
 695                               uint32_t flags, int mode, int copy_lvb,
 696                               char __user *buf, size_t count)
 697{
 698#ifdef CONFIG_COMPAT
 699        struct dlm_lock_result32 result32;
 700#endif
 701        struct dlm_lock_result result;
 702        void *resultptr;
 703        int error=0;
 704        int len;
 705        int struct_len;
 706
 707        memset(&result, 0, sizeof(struct dlm_lock_result));
 708        result.version[0] = DLM_DEVICE_VERSION_MAJOR;
 709        result.version[1] = DLM_DEVICE_VERSION_MINOR;
 710        result.version[2] = DLM_DEVICE_VERSION_PATCH;
 711        memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
 712        result.user_lksb = ua->user_lksb;
 713
 714        /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
 715           in a conversion unless the conversion is successful.  See code
 716           in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
 717           notes that a new blocking AST address and parameter are set even if
 718           the conversion fails, so maybe we should just do that. */
 719
 720        if (flags & DLM_CB_BAST) {
 721                result.user_astaddr = ua->bastaddr;
 722                result.user_astparam = ua->bastparam;
 723                result.bast_mode = mode;
 724        } else {
 725                result.user_astaddr = ua->castaddr;
 726                result.user_astparam = ua->castparam;
 727        }
 728
 729#ifdef CONFIG_COMPAT
 730        if (compat)
 731                len = sizeof(struct dlm_lock_result32);
 732        else
 733#endif
 734                len = sizeof(struct dlm_lock_result);
 735        struct_len = len;
 736
 737        /* copy lvb to userspace if there is one, it's been updated, and
 738           the user buffer has space for it */
 739
 740        if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
 741                if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
 742                                 DLM_USER_LVB_LEN)) {
 743                        error = -EFAULT;
 744                        goto out;
 745                }
 746
 747                result.lvb_offset = len;
 748                len += DLM_USER_LVB_LEN;
 749        }
 750
 751        result.length = len;
 752        resultptr = &result;
 753#ifdef CONFIG_COMPAT
 754        if (compat) {
 755                compat_output(&result, &result32);
 756                resultptr = &result32;
 757        }
 758#endif
 759
 760        if (copy_to_user(buf, resultptr, struct_len))
 761                error = -EFAULT;
 762        else
 763                error = len;
 764 out:
 765        return error;
 766}
 767
 768static int copy_version_to_user(char __user *buf, size_t count)
 769{
 770        struct dlm_device_version ver;
 771
 772        memset(&ver, 0, sizeof(struct dlm_device_version));
 773        ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
 774        ver.version[1] = DLM_DEVICE_VERSION_MINOR;
 775        ver.version[2] = DLM_DEVICE_VERSION_PATCH;
 776
 777        if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
 778                return -EFAULT;
 779        return sizeof(struct dlm_device_version);
 780}
 781
 782/* a read returns a single ast described in a struct dlm_lock_result */
 783
 784static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 785                           loff_t *ppos)
 786{
 787        struct dlm_user_proc *proc = file->private_data;
 788        struct dlm_lkb *lkb;
 789        DECLARE_WAITQUEUE(wait, current);
 790        struct dlm_callback cb;
 791        int rv, resid, copy_lvb = 0;
 792
 793        if (count == sizeof(struct dlm_device_version)) {
 794                rv = copy_version_to_user(buf, count);
 795                return rv;
 796        }
 797
 798        if (!proc) {
 799                log_print("non-version read from control device %zu", count);
 800                return -EINVAL;
 801        }
 802
 803#ifdef CONFIG_COMPAT
 804        if (count < sizeof(struct dlm_lock_result32))
 805#else
 806        if (count < sizeof(struct dlm_lock_result))
 807#endif
 808                return -EINVAL;
 809
 810 try_another:
 811
 812        /* do we really need this? can a read happen after a close? */
 813        if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
 814                return -EINVAL;
 815
 816        spin_lock(&proc->asts_spin);
 817        if (list_empty(&proc->asts)) {
 818                if (file->f_flags & O_NONBLOCK) {
 819                        spin_unlock(&proc->asts_spin);
 820                        return -EAGAIN;
 821                }
 822
 823                add_wait_queue(&proc->wait, &wait);
 824
 825        repeat:
 826                set_current_state(TASK_INTERRUPTIBLE);
 827                if (list_empty(&proc->asts) && !signal_pending(current)) {
 828                        spin_unlock(&proc->asts_spin);
 829                        schedule();
 830                        spin_lock(&proc->asts_spin);
 831                        goto repeat;
 832                }
 833                set_current_state(TASK_RUNNING);
 834                remove_wait_queue(&proc->wait, &wait);
 835
 836                if (signal_pending(current)) {
 837                        spin_unlock(&proc->asts_spin);
 838                        return -ERESTARTSYS;
 839                }
 840        }
 841
 842        /* if we empty lkb_callbacks, we don't want to unlock the spinlock
 843           without removing lkb_cb_list; so empty lkb_cb_list is always
 844           consistent with empty lkb_callbacks */
 845
 846        lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
 847
 848        rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
 849        if (rv < 0) {
 850                /* this shouldn't happen; lkb should have been removed from
 851                   list when resid was zero */
 852                log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
 853                list_del_init(&lkb->lkb_cb_list);
 854                spin_unlock(&proc->asts_spin);
 855                /* removes ref for proc->asts, may cause lkb to be freed */
 856                dlm_put_lkb(lkb);
 857                goto try_another;
 858        }
 859        if (!resid)
 860                list_del_init(&lkb->lkb_cb_list);
 861        spin_unlock(&proc->asts_spin);
 862
 863        if (cb.flags & DLM_CB_SKIP) {
 864                /* removes ref for proc->asts, may cause lkb to be freed */
 865                if (!resid)
 866                        dlm_put_lkb(lkb);
 867                goto try_another;
 868        }
 869
 870        if (cb.flags & DLM_CB_CAST) {
 871                int old_mode, new_mode;
 872
 873                old_mode = lkb->lkb_last_cast.mode;
 874                new_mode = cb.mode;
 875
 876                if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
 877                    dlm_lvb_operations[old_mode + 1][new_mode + 1])
 878                        copy_lvb = 1;
 879
 880                lkb->lkb_lksb->sb_status = cb.sb_status;
 881                lkb->lkb_lksb->sb_flags = cb.sb_flags;
 882        }
 883
 884        rv = copy_result_to_user(lkb->lkb_ua,
 885                                 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
 886                                 cb.flags, cb.mode, copy_lvb, buf, count);
 887
 888        /* removes ref for proc->asts, may cause lkb to be freed */
 889        if (!resid)
 890                dlm_put_lkb(lkb);
 891
 892        return rv;
 893}
 894
 895static unsigned int device_poll(struct file *file, poll_table *wait)
 896{
 897        struct dlm_user_proc *proc = file->private_data;
 898
 899        poll_wait(file, &proc->wait, wait);
 900
 901        spin_lock(&proc->asts_spin);
 902        if (!list_empty(&proc->asts)) {
 903                spin_unlock(&proc->asts_spin);
 904                return POLLIN | POLLRDNORM;
 905        }
 906        spin_unlock(&proc->asts_spin);
 907        return 0;
 908}
 909
 910int dlm_user_daemon_available(void)
 911{
 912        /* dlm_controld hasn't started (or, has started, but not
 913           properly populated configfs) */
 914
 915        if (!dlm_our_nodeid())
 916                return 0;
 917
 918        /* This is to deal with versions of dlm_controld that don't
 919           know about the monitor device.  We assume that if the
 920           dlm_controld was started (above), but the monitor device
 921           was never opened, that it's an old version.  dlm_controld
 922           should open the monitor device before populating configfs. */
 923
 924        if (dlm_monitor_unused)
 925                return 1;
 926
 927        return atomic_read(&dlm_monitor_opened) ? 1 : 0;
 928}
 929
 930static int ctl_device_open(struct inode *inode, struct file *file)
 931{
 932        file->private_data = NULL;
 933        return 0;
 934}
 935
 936static int ctl_device_close(struct inode *inode, struct file *file)
 937{
 938        return 0;
 939}
 940
 941static int monitor_device_open(struct inode *inode, struct file *file)
 942{
 943        atomic_inc(&dlm_monitor_opened);
 944        dlm_monitor_unused = 0;
 945        return 0;
 946}
 947
 948static int monitor_device_close(struct inode *inode, struct file *file)
 949{
 950        if (atomic_dec_and_test(&dlm_monitor_opened))
 951                dlm_stop_lockspaces();
 952        return 0;
 953}
 954
 955static const struct file_operations device_fops = {
 956        .open    = device_open,
 957        .release = device_close,
 958        .read    = device_read,
 959        .write   = device_write,
 960        .poll    = device_poll,
 961        .owner   = THIS_MODULE,
 962        .llseek  = noop_llseek,
 963};
 964
 965static const struct file_operations ctl_device_fops = {
 966        .open    = ctl_device_open,
 967        .release = ctl_device_close,
 968        .read    = device_read,
 969        .write   = device_write,
 970        .owner   = THIS_MODULE,
 971        .llseek  = noop_llseek,
 972};
 973
 974static struct miscdevice ctl_device = {
 975        .name  = "dlm-control",
 976        .fops  = &ctl_device_fops,
 977        .minor = MISC_DYNAMIC_MINOR,
 978};
 979
 980static const struct file_operations monitor_device_fops = {
 981        .open    = monitor_device_open,
 982        .release = monitor_device_close,
 983        .owner   = THIS_MODULE,
 984        .llseek  = noop_llseek,
 985};
 986
 987static struct miscdevice monitor_device = {
 988        .name  = "dlm-monitor",
 989        .fops  = &monitor_device_fops,
 990        .minor = MISC_DYNAMIC_MINOR,
 991};
 992
 993int __init dlm_user_init(void)
 994{
 995        int error;
 996
 997        atomic_set(&dlm_monitor_opened, 0);
 998
 999        error = misc_register(&ctl_device);
1000        if (error) {
1001                log_print("misc_register failed for control device");
1002                goto out;
1003        }
1004
1005        error = misc_register(&monitor_device);
1006        if (error) {
1007                log_print("misc_register failed for monitor device");
1008                misc_deregister(&ctl_device);
1009        }
1010 out:
1011        return error;
1012}
1013
1014void dlm_user_exit(void)
1015{
1016        misc_deregister(&ctl_device);
1017        misc_deregister(&monitor_device);
1018}
1019
1020
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