linux/fs/dlm/user.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) 2006-2010 Red Hat, Inc.  All rights reserved.
   4 */
   5
   6#include <linux/miscdevice.h>
   7#include <linux/init.h>
   8#include <linux/wait.h>
   9#include <linux/file.h>
  10#include <linux/fs.h>
  11#include <linux/poll.h>
  12#include <linux/signal.h>
  13#include <linux/spinlock.h>
  14#include <linux/dlm.h>
  15#include <linux/dlm_device.h>
  16#include <linux/slab.h>
  17#include <linux/sched/signal.h>
  18
  19#include "dlm_internal.h"
  20#include "lockspace.h"
  21#include "lock.h"
  22#include "lvb_table.h"
  23#include "user.h"
  24#include "ast.h"
  25#include "config.h"
  26
  27static const char name_prefix[] = "dlm";
  28static const struct file_operations device_fops;
  29static atomic_t dlm_monitor_opened;
  30static int dlm_monitor_unused = 1;
  31
  32#ifdef CONFIG_COMPAT
  33
  34struct dlm_lock_params32 {
  35        __u8 mode;
  36        __u8 namelen;
  37        __u16 unused;
  38        __u32 flags;
  39        __u32 lkid;
  40        __u32 parent;
  41        __u64 xid;
  42        __u64 timeout;
  43        __u32 castparam;
  44        __u32 castaddr;
  45        __u32 bastparam;
  46        __u32 bastaddr;
  47        __u32 lksb;
  48        char lvb[DLM_USER_LVB_LEN];
  49        char name[0];
  50};
  51
  52struct dlm_write_request32 {
  53        __u32 version[3];
  54        __u8 cmd;
  55        __u8 is64bit;
  56        __u8 unused[2];
  57
  58        union  {
  59                struct dlm_lock_params32 lock;
  60                struct dlm_lspace_params lspace;
  61                struct dlm_purge_params purge;
  62        } i;
  63};
  64
  65struct dlm_lksb32 {
  66        __u32 sb_status;
  67        __u32 sb_lkid;
  68        __u8 sb_flags;
  69        __u32 sb_lvbptr;
  70};
  71
  72struct dlm_lock_result32 {
  73        __u32 version[3];
  74        __u32 length;
  75        __u32 user_astaddr;
  76        __u32 user_astparam;
  77        __u32 user_lksb;
  78        struct dlm_lksb32 lksb;
  79        __u8 bast_mode;
  80        __u8 unused[3];
  81        /* Offsets may be zero if no data is present */
  82        __u32 lvb_offset;
  83};
  84
  85static void compat_input(struct dlm_write_request *kb,
  86                         struct dlm_write_request32 *kb32,
  87                         int namelen)
  88{
  89        kb->version[0] = kb32->version[0];
  90        kb->version[1] = kb32->version[1];
  91        kb->version[2] = kb32->version[2];
  92
  93        kb->cmd = kb32->cmd;
  94        kb->is64bit = kb32->is64bit;
  95        if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
  96            kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
  97                kb->i.lspace.flags = kb32->i.lspace.flags;
  98                kb->i.lspace.minor = kb32->i.lspace.minor;
  99                memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
 100        } else if (kb->cmd == DLM_USER_PURGE) {
 101                kb->i.purge.nodeid = kb32->i.purge.nodeid;
 102                kb->i.purge.pid = kb32->i.purge.pid;
 103        } else {
 104                kb->i.lock.mode = kb32->i.lock.mode;
 105                kb->i.lock.namelen = kb32->i.lock.namelen;
 106                kb->i.lock.flags = kb32->i.lock.flags;
 107                kb->i.lock.lkid = kb32->i.lock.lkid;
 108                kb->i.lock.parent = kb32->i.lock.parent;
 109                kb->i.lock.xid = kb32->i.lock.xid;
 110                kb->i.lock.timeout = kb32->i.lock.timeout;
 111                kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
 112                kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
 113                kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
 114                kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
 115                kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
 116                memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
 117                memcpy(kb->i.lock.name, kb32->i.lock.name, namelen);
 118        }
 119}
 120
 121static void compat_output(struct dlm_lock_result *res,
 122                          struct dlm_lock_result32 *res32)
 123{
 124        memset(res32, 0, sizeof(*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                /* this has to be set to NULL
 359                 * to avoid a double-free in dlm_device_deregister
 360                 */
 361                ls->ls_device.name = NULL;
 362        }
 363fail:
 364        return error;
 365}
 366
 367int dlm_device_deregister(struct dlm_ls *ls)
 368{
 369        /* The device is not registered.  This happens when the lockspace
 370           was never used from userspace, or when device_create_lockspace()
 371           calls dlm_release_lockspace() after the register fails. */
 372        if (!ls->ls_device.name)
 373                return 0;
 374
 375        misc_deregister(&ls->ls_device);
 376        kfree(ls->ls_device.name);
 377        return 0;
 378}
 379
 380static int device_user_purge(struct dlm_user_proc *proc,
 381                             struct dlm_purge_params *params)
 382{
 383        struct dlm_ls *ls;
 384        int error;
 385
 386        ls = dlm_find_lockspace_local(proc->lockspace);
 387        if (!ls)
 388                return -ENOENT;
 389
 390        error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
 391
 392        dlm_put_lockspace(ls);
 393        return error;
 394}
 395
 396static int device_create_lockspace(struct dlm_lspace_params *params)
 397{
 398        dlm_lockspace_t *lockspace;
 399        struct dlm_ls *ls;
 400        int error;
 401
 402        if (!capable(CAP_SYS_ADMIN))
 403                return -EPERM;
 404
 405        error = dlm_new_lockspace(params->name, dlm_config.ci_cluster_name, params->flags,
 406                                  DLM_USER_LVB_LEN, NULL, NULL, NULL,
 407                                  &lockspace);
 408        if (error)
 409                return error;
 410
 411        ls = dlm_find_lockspace_local(lockspace);
 412        if (!ls)
 413                return -ENOENT;
 414
 415        error = dlm_device_register(ls, params->name);
 416        dlm_put_lockspace(ls);
 417
 418        if (error)
 419                dlm_release_lockspace(lockspace, 0);
 420        else
 421                error = ls->ls_device.minor;
 422
 423        return error;
 424}
 425
 426static int device_remove_lockspace(struct dlm_lspace_params *params)
 427{
 428        dlm_lockspace_t *lockspace;
 429        struct dlm_ls *ls;
 430        int error, force = 0;
 431
 432        if (!capable(CAP_SYS_ADMIN))
 433                return -EPERM;
 434
 435        ls = dlm_find_lockspace_device(params->minor);
 436        if (!ls)
 437                return -ENOENT;
 438
 439        if (params->flags & DLM_USER_LSFLG_FORCEFREE)
 440                force = 2;
 441
 442        lockspace = ls->ls_local_handle;
 443        dlm_put_lockspace(ls);
 444
 445        /* The final dlm_release_lockspace waits for references to go to
 446           zero, so all processes will need to close their device for the
 447           ls before the release will proceed.  release also calls the
 448           device_deregister above.  Converting a positive return value
 449           from release to zero means that userspace won't know when its
 450           release was the final one, but it shouldn't need to know. */
 451
 452        error = dlm_release_lockspace(lockspace, force);
 453        if (error > 0)
 454                error = 0;
 455        return error;
 456}
 457
 458/* Check the user's version matches ours */
 459static int check_version(struct dlm_write_request *req)
 460{
 461        if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
 462            (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
 463             req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
 464
 465                printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
 466                       "user (%d.%d.%d) kernel (%d.%d.%d)\n",
 467                       current->comm,
 468                       task_pid_nr(current),
 469                       req->version[0],
 470                       req->version[1],
 471                       req->version[2],
 472                       DLM_DEVICE_VERSION_MAJOR,
 473                       DLM_DEVICE_VERSION_MINOR,
 474                       DLM_DEVICE_VERSION_PATCH);
 475                return -EINVAL;
 476        }
 477        return 0;
 478}
 479
 480/*
 481 * device_write
 482 *
 483 *   device_user_lock
 484 *     dlm_user_request -> request_lock
 485 *     dlm_user_convert -> convert_lock
 486 *
 487 *   device_user_unlock
 488 *     dlm_user_unlock -> unlock_lock
 489 *     dlm_user_cancel -> cancel_lock
 490 *
 491 *   device_create_lockspace
 492 *     dlm_new_lockspace
 493 *
 494 *   device_remove_lockspace
 495 *     dlm_release_lockspace
 496 */
 497
 498/* a write to a lockspace device is a lock or unlock request, a write
 499   to the control device is to create/remove a lockspace */
 500
 501static ssize_t device_write(struct file *file, const char __user *buf,
 502                            size_t count, loff_t *ppos)
 503{
 504        struct dlm_user_proc *proc = file->private_data;
 505        struct dlm_write_request *kbuf;
 506        int error;
 507
 508#ifdef CONFIG_COMPAT
 509        if (count < sizeof(struct dlm_write_request32))
 510#else
 511        if (count < sizeof(struct dlm_write_request))
 512#endif
 513                return -EINVAL;
 514
 515        /*
 516         * can't compare against COMPAT/dlm_write_request32 because
 517         * we don't yet know if is64bit is zero
 518         */
 519        if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
 520                return -EINVAL;
 521
 522        kbuf = memdup_user_nul(buf, count);
 523        if (IS_ERR(kbuf))
 524                return PTR_ERR(kbuf);
 525
 526        if (check_version(kbuf)) {
 527                error = -EBADE;
 528                goto out_free;
 529        }
 530
 531#ifdef CONFIG_COMPAT
 532        if (!kbuf->is64bit) {
 533                struct dlm_write_request32 *k32buf;
 534                int namelen = 0;
 535
 536                if (count > sizeof(struct dlm_write_request32))
 537                        namelen = count - sizeof(struct dlm_write_request32);
 538
 539                k32buf = (struct dlm_write_request32 *)kbuf;
 540
 541                /* add 1 after namelen so that the name string is terminated */
 542                kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
 543                               GFP_NOFS);
 544                if (!kbuf) {
 545                        kfree(k32buf);
 546                        return -ENOMEM;
 547                }
 548
 549                if (proc)
 550                        set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
 551
 552                compat_input(kbuf, k32buf, namelen);
 553                kfree(k32buf);
 554        }
 555#endif
 556
 557        /* do we really need this? can a write happen after a close? */
 558        if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
 559            (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
 560                error = -EINVAL;
 561                goto out_free;
 562        }
 563
 564        error = -EINVAL;
 565
 566        switch (kbuf->cmd)
 567        {
 568        case DLM_USER_LOCK:
 569                if (!proc) {
 570                        log_print("no locking on control device");
 571                        goto out_free;
 572                }
 573                error = device_user_lock(proc, &kbuf->i.lock);
 574                break;
 575
 576        case DLM_USER_UNLOCK:
 577                if (!proc) {
 578                        log_print("no locking on control device");
 579                        goto out_free;
 580                }
 581                error = device_user_unlock(proc, &kbuf->i.lock);
 582                break;
 583
 584        case DLM_USER_DEADLOCK:
 585                if (!proc) {
 586                        log_print("no locking on control device");
 587                        goto out_free;
 588                }
 589                error = device_user_deadlock(proc, &kbuf->i.lock);
 590                break;
 591
 592        case DLM_USER_CREATE_LOCKSPACE:
 593                if (proc) {
 594                        log_print("create/remove only on control device");
 595                        goto out_free;
 596                }
 597                error = device_create_lockspace(&kbuf->i.lspace);
 598                break;
 599
 600        case DLM_USER_REMOVE_LOCKSPACE:
 601                if (proc) {
 602                        log_print("create/remove only on control device");
 603                        goto out_free;
 604                }
 605                error = device_remove_lockspace(&kbuf->i.lspace);
 606                break;
 607
 608        case DLM_USER_PURGE:
 609                if (!proc) {
 610                        log_print("no locking on control device");
 611                        goto out_free;
 612                }
 613                error = device_user_purge(proc, &kbuf->i.purge);
 614                break;
 615
 616        default:
 617                log_print("Unknown command passed to DLM device : %d\n",
 618                          kbuf->cmd);
 619        }
 620
 621 out_free:
 622        kfree(kbuf);
 623        return error;
 624}
 625
 626/* Every process that opens the lockspace device has its own "proc" structure
 627   hanging off the open file that's used to keep track of locks owned by the
 628   process and asts that need to be delivered to the process. */
 629
 630static int device_open(struct inode *inode, struct file *file)
 631{
 632        struct dlm_user_proc *proc;
 633        struct dlm_ls *ls;
 634
 635        ls = dlm_find_lockspace_device(iminor(inode));
 636        if (!ls)
 637                return -ENOENT;
 638
 639        proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
 640        if (!proc) {
 641                dlm_put_lockspace(ls);
 642                return -ENOMEM;
 643        }
 644
 645        proc->lockspace = ls->ls_local_handle;
 646        INIT_LIST_HEAD(&proc->asts);
 647        INIT_LIST_HEAD(&proc->locks);
 648        INIT_LIST_HEAD(&proc->unlocking);
 649        spin_lock_init(&proc->asts_spin);
 650        spin_lock_init(&proc->locks_spin);
 651        init_waitqueue_head(&proc->wait);
 652        file->private_data = proc;
 653
 654        return 0;
 655}
 656
 657static int device_close(struct inode *inode, struct file *file)
 658{
 659        struct dlm_user_proc *proc = file->private_data;
 660        struct dlm_ls *ls;
 661
 662        ls = dlm_find_lockspace_local(proc->lockspace);
 663        if (!ls)
 664                return -ENOENT;
 665
 666        set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
 667
 668        dlm_clear_proc_locks(ls, proc);
 669
 670        /* at this point no more lkb's should exist for this lockspace,
 671           so there's no chance of dlm_user_add_ast() being called and
 672           looking for lkb->ua->proc */
 673
 674        kfree(proc);
 675        file->private_data = NULL;
 676
 677        dlm_put_lockspace(ls);
 678        dlm_put_lockspace(ls);  /* for the find in device_open() */
 679
 680        /* FIXME: AUTOFREE: if this ls is no longer used do
 681           device_remove_lockspace() */
 682
 683        return 0;
 684}
 685
 686static int copy_result_to_user(struct dlm_user_args *ua, int compat,
 687                               uint32_t flags, int mode, int copy_lvb,
 688                               char __user *buf, size_t count)
 689{
 690#ifdef CONFIG_COMPAT
 691        struct dlm_lock_result32 result32;
 692#endif
 693        struct dlm_lock_result result;
 694        void *resultptr;
 695        int error=0;
 696        int len;
 697        int struct_len;
 698
 699        memset(&result, 0, sizeof(struct dlm_lock_result));
 700        result.version[0] = DLM_DEVICE_VERSION_MAJOR;
 701        result.version[1] = DLM_DEVICE_VERSION_MINOR;
 702        result.version[2] = DLM_DEVICE_VERSION_PATCH;
 703        memcpy(&result.lksb, &ua->lksb, offsetof(struct dlm_lksb, sb_lvbptr));
 704        result.user_lksb = ua->user_lksb;
 705
 706        /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
 707           in a conversion unless the conversion is successful.  See code
 708           in dlm_user_convert() for updating ua from ua_tmp.  OpenVMS, though,
 709           notes that a new blocking AST address and parameter are set even if
 710           the conversion fails, so maybe we should just do that. */
 711
 712        if (flags & DLM_CB_BAST) {
 713                result.user_astaddr = ua->bastaddr;
 714                result.user_astparam = ua->bastparam;
 715                result.bast_mode = mode;
 716        } else {
 717                result.user_astaddr = ua->castaddr;
 718                result.user_astparam = ua->castparam;
 719        }
 720
 721#ifdef CONFIG_COMPAT
 722        if (compat)
 723                len = sizeof(struct dlm_lock_result32);
 724        else
 725#endif
 726                len = sizeof(struct dlm_lock_result);
 727        struct_len = len;
 728
 729        /* copy lvb to userspace if there is one, it's been updated, and
 730           the user buffer has space for it */
 731
 732        if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
 733                if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
 734                                 DLM_USER_LVB_LEN)) {
 735                        error = -EFAULT;
 736                        goto out;
 737                }
 738
 739                result.lvb_offset = len;
 740                len += DLM_USER_LVB_LEN;
 741        }
 742
 743        result.length = len;
 744        resultptr = &result;
 745#ifdef CONFIG_COMPAT
 746        if (compat) {
 747                compat_output(&result, &result32);
 748                resultptr = &result32;
 749        }
 750#endif
 751
 752        if (copy_to_user(buf, resultptr, struct_len))
 753                error = -EFAULT;
 754        else
 755                error = len;
 756 out:
 757        return error;
 758}
 759
 760static int copy_version_to_user(char __user *buf, size_t count)
 761{
 762        struct dlm_device_version ver;
 763
 764        memset(&ver, 0, sizeof(struct dlm_device_version));
 765        ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
 766        ver.version[1] = DLM_DEVICE_VERSION_MINOR;
 767        ver.version[2] = DLM_DEVICE_VERSION_PATCH;
 768
 769        if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
 770                return -EFAULT;
 771        return sizeof(struct dlm_device_version);
 772}
 773
 774/* a read returns a single ast described in a struct dlm_lock_result */
 775
 776static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 777                           loff_t *ppos)
 778{
 779        struct dlm_user_proc *proc = file->private_data;
 780        struct dlm_lkb *lkb;
 781        DECLARE_WAITQUEUE(wait, current);
 782        struct dlm_callback cb;
 783        int rv, resid, copy_lvb = 0;
 784        int old_mode, new_mode;
 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        /* rem_lkb_callback sets a new lkb_last_cast */
 842        old_mode = lkb->lkb_last_cast.mode;
 843
 844        rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
 845        if (rv < 0) {
 846                /* this shouldn't happen; lkb should have been removed from
 847                   list when resid was zero */
 848                log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
 849                list_del_init(&lkb->lkb_cb_list);
 850                spin_unlock(&proc->asts_spin);
 851                /* removes ref for proc->asts, may cause lkb to be freed */
 852                dlm_put_lkb(lkb);
 853                goto try_another;
 854        }
 855        if (!resid)
 856                list_del_init(&lkb->lkb_cb_list);
 857        spin_unlock(&proc->asts_spin);
 858
 859        if (cb.flags & DLM_CB_SKIP) {
 860                /* removes ref for proc->asts, may cause lkb to be freed */
 861                if (!resid)
 862                        dlm_put_lkb(lkb);
 863                goto try_another;
 864        }
 865
 866        if (cb.flags & DLM_CB_CAST) {
 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 __poll_t 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 EPOLLIN | EPOLLRDNORM;
 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