linux/drivers/md/dm-log-userspace-base.c
<<
>>
Prefs
   1/*
   2 * Copyright (C) 2006-2009 Red Hat, Inc.
   3 *
   4 * This file is released under the LGPL.
   5 */
   6
   7#include <linux/bio.h>
   8#include <linux/slab.h>
   9#include <linux/jiffies.h>
  10#include <linux/dm-dirty-log.h>
  11#include <linux/device-mapper.h>
  12#include <linux/dm-log-userspace.h>
  13#include <linux/module.h>
  14#include <linux/workqueue.h>
  15
  16#include "dm-log-userspace-transfer.h"
  17
  18#define DM_LOG_USERSPACE_VSN "1.3.0"
  19
  20#define FLUSH_ENTRY_POOL_SIZE 16
  21
  22struct dm_dirty_log_flush_entry {
  23        int type;
  24        region_t region;
  25        struct list_head list;
  26};
  27
  28/*
  29 * This limit on the number of mark and clear request is, to a degree,
  30 * arbitrary.  However, there is some basis for the choice in the limits
  31 * imposed on the size of data payload by dm-log-userspace-transfer.c:
  32 * dm_consult_userspace().
  33 */
  34#define MAX_FLUSH_GROUP_COUNT 32
  35
  36struct log_c {
  37        struct dm_target *ti;
  38        struct dm_dev *log_dev;
  39
  40        char *usr_argv_str;
  41        uint32_t usr_argc;
  42
  43        uint32_t region_size;
  44        region_t region_count;
  45        uint64_t luid;
  46        char uuid[DM_UUID_LEN];
  47
  48        /*
  49         * Mark and clear requests are held until a flush is issued
  50         * so that we can group, and thereby limit, the amount of
  51         * network traffic between kernel and userspace.  The 'flush_lock'
  52         * is used to protect these lists.
  53         */
  54        spinlock_t flush_lock;
  55        struct list_head mark_list;
  56        struct list_head clear_list;
  57
  58        /*
  59         * in_sync_hint gets set when doing is_remote_recovering.  It
  60         * represents the first region that needs recovery.  IOW, the
  61         * first zero bit of sync_bits.  This can be useful for to limit
  62         * traffic for calls like is_remote_recovering and get_resync_work,
  63         * but be take care in its use for anything else.
  64         */
  65        uint64_t in_sync_hint;
  66
  67        /*
  68         * Workqueue for flush of clear region requests.
  69         */
  70        struct workqueue_struct *dmlog_wq;
  71        struct delayed_work flush_log_work;
  72        atomic_t sched_flush;
  73
  74        /*
  75         * Combine userspace flush and mark requests for efficiency.
  76         */
  77        uint32_t integrated_flush;
  78
  79        mempool_t flush_entry_pool;
  80};
  81
  82static struct kmem_cache *_flush_entry_cache;
  83
  84static int userspace_do_request(struct log_c *lc, const char *uuid,
  85                                int request_type, char *data, size_t data_size,
  86                                char *rdata, size_t *rdata_size)
  87{
  88        int r;
  89
  90        /*
  91         * If the server isn't there, -ESRCH is returned,
  92         * and we must keep trying until the server is
  93         * restored.
  94         */
  95retry:
  96        r = dm_consult_userspace(uuid, lc->luid, request_type, data,
  97                                 data_size, rdata, rdata_size);
  98
  99        if (r != -ESRCH)
 100                return r;
 101
 102        DMERR(" Userspace log server not found.");
 103        while (1) {
 104                set_current_state(TASK_INTERRUPTIBLE);
 105                schedule_timeout(2*HZ);
 106                DMWARN("Attempting to contact userspace log server...");
 107                r = dm_consult_userspace(uuid, lc->luid, DM_ULOG_CTR,
 108                                         lc->usr_argv_str,
 109                                         strlen(lc->usr_argv_str) + 1,
 110                                         NULL, NULL);
 111                if (!r)
 112                        break;
 113        }
 114        DMINFO("Reconnected to userspace log server... DM_ULOG_CTR complete");
 115        r = dm_consult_userspace(uuid, lc->luid, DM_ULOG_RESUME, NULL,
 116                                 0, NULL, NULL);
 117        if (!r)
 118                goto retry;
 119
 120        DMERR("Error trying to resume userspace log: %d", r);
 121
 122        return -ESRCH;
 123}
 124
 125static int build_constructor_string(struct dm_target *ti,
 126                                    unsigned argc, char **argv,
 127                                    char **ctr_str)
 128{
 129        int i, str_size;
 130        char *str = NULL;
 131
 132        *ctr_str = NULL;
 133
 134        /*
 135         * Determine overall size of the string.
 136         */
 137        for (i = 0, str_size = 0; i < argc; i++)
 138                str_size += strlen(argv[i]) + 1; /* +1 for space between args */
 139
 140        str_size += 20; /* Max number of chars in a printed u64 number */
 141
 142        str = kzalloc(str_size, GFP_KERNEL);
 143        if (!str) {
 144                DMWARN("Unable to allocate memory for constructor string");
 145                return -ENOMEM;
 146        }
 147
 148        str_size = sprintf(str, "%llu", (unsigned long long)ti->len);
 149        for (i = 0; i < argc; i++)
 150                str_size += sprintf(str + str_size, " %s", argv[i]);
 151
 152        *ctr_str = str;
 153        return str_size;
 154}
 155
 156static void do_flush(struct work_struct *work)
 157{
 158        int r;
 159        struct log_c *lc = container_of(work, struct log_c, flush_log_work.work);
 160
 161        atomic_set(&lc->sched_flush, 0);
 162
 163        r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH, NULL, 0, NULL, NULL);
 164
 165        if (r)
 166                dm_table_event(lc->ti->table);
 167}
 168
 169/*
 170 * userspace_ctr
 171 *
 172 * argv contains:
 173 *      <UUID> [integrated_flush] <other args>
 174 * Where 'other args' are the userspace implementation-specific log
 175 * arguments.
 176 *
 177 * Example:
 178 *      <UUID> [integrated_flush] clustered-disk <arg count> <log dev>
 179 *      <region_size> [[no]sync]
 180 *
 181 * This module strips off the <UUID> and uses it for identification
 182 * purposes when communicating with userspace about a log.
 183 *
 184 * If integrated_flush is defined, the kernel combines flush
 185 * and mark requests.
 186 *
 187 * The rest of the line, beginning with 'clustered-disk', is passed
 188 * to the userspace ctr function.
 189 */
 190static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 191                         unsigned argc, char **argv)
 192{
 193        int r = 0;
 194        int str_size;
 195        char *ctr_str = NULL;
 196        struct log_c *lc = NULL;
 197        uint64_t rdata;
 198        size_t rdata_size = sizeof(rdata);
 199        char *devices_rdata = NULL;
 200        size_t devices_rdata_size = DM_NAME_LEN;
 201
 202        if (argc < 3) {
 203                DMWARN("Too few arguments to userspace dirty log");
 204                return -EINVAL;
 205        }
 206
 207        lc = kzalloc(sizeof(*lc), GFP_KERNEL);
 208        if (!lc) {
 209                DMWARN("Unable to allocate userspace log context.");
 210                return -ENOMEM;
 211        }
 212
 213        /* The ptr value is sufficient for local unique id */
 214        lc->luid = (unsigned long)lc;
 215
 216        lc->ti = ti;
 217
 218        if (strlen(argv[0]) > (DM_UUID_LEN - 1)) {
 219                DMWARN("UUID argument too long.");
 220                kfree(lc);
 221                return -EINVAL;
 222        }
 223
 224        lc->usr_argc = argc;
 225
 226        strncpy(lc->uuid, argv[0], DM_UUID_LEN);
 227        argc--;
 228        argv++;
 229        spin_lock_init(&lc->flush_lock);
 230        INIT_LIST_HEAD(&lc->mark_list);
 231        INIT_LIST_HEAD(&lc->clear_list);
 232
 233        if (!strcasecmp(argv[0], "integrated_flush")) {
 234                lc->integrated_flush = 1;
 235                argc--;
 236                argv++;
 237        }
 238
 239        str_size = build_constructor_string(ti, argc, argv, &ctr_str);
 240        if (str_size < 0) {
 241                kfree(lc);
 242                return str_size;
 243        }
 244
 245        devices_rdata = kzalloc(devices_rdata_size, GFP_KERNEL);
 246        if (!devices_rdata) {
 247                DMERR("Failed to allocate memory for device information");
 248                r = -ENOMEM;
 249                goto out;
 250        }
 251
 252        r = mempool_init_slab_pool(&lc->flush_entry_pool, FLUSH_ENTRY_POOL_SIZE,
 253                                   _flush_entry_cache);
 254        if (r) {
 255                DMERR("Failed to create flush_entry_pool");
 256                goto out;
 257        }
 258
 259        /*
 260         * Send table string and get back any opened device.
 261         */
 262        r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_CTR,
 263                                 ctr_str, str_size,
 264                                 devices_rdata, &devices_rdata_size);
 265
 266        if (r < 0) {
 267                if (r == -ESRCH)
 268                        DMERR("Userspace log server not found");
 269                else
 270                        DMERR("Userspace log server failed to create log");
 271                goto out;
 272        }
 273
 274        /* Since the region size does not change, get it now */
 275        rdata_size = sizeof(rdata);
 276        r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_GET_REGION_SIZE,
 277                                 NULL, 0, (char *)&rdata, &rdata_size);
 278
 279        if (r) {
 280                DMERR("Failed to get region size of dirty log");
 281                goto out;
 282        }
 283
 284        lc->region_size = (uint32_t)rdata;
 285        lc->region_count = dm_sector_div_up(ti->len, lc->region_size);
 286
 287        if (devices_rdata_size) {
 288                if (devices_rdata[devices_rdata_size - 1] != '\0') {
 289                        DMERR("DM_ULOG_CTR device return string not properly terminated");
 290                        r = -EINVAL;
 291                        goto out;
 292                }
 293                r = dm_get_device(ti, devices_rdata,
 294                                  dm_table_get_mode(ti->table), &lc->log_dev);
 295                if (r)
 296                        DMERR("Failed to register %s with device-mapper",
 297                              devices_rdata);
 298        }
 299
 300        if (lc->integrated_flush) {
 301                lc->dmlog_wq = alloc_workqueue("dmlogd", WQ_MEM_RECLAIM, 0);
 302                if (!lc->dmlog_wq) {
 303                        DMERR("couldn't start dmlogd");
 304                        r = -ENOMEM;
 305                        goto out;
 306                }
 307
 308                INIT_DELAYED_WORK(&lc->flush_log_work, do_flush);
 309                atomic_set(&lc->sched_flush, 0);
 310        }
 311
 312out:
 313        kfree(devices_rdata);
 314        if (r) {
 315                mempool_exit(&lc->flush_entry_pool);
 316                kfree(lc);
 317                kfree(ctr_str);
 318        } else {
 319                lc->usr_argv_str = ctr_str;
 320                log->context = lc;
 321        }
 322
 323        return r;
 324}
 325
 326static void userspace_dtr(struct dm_dirty_log *log)
 327{
 328        struct log_c *lc = log->context;
 329
 330        if (lc->integrated_flush) {
 331                /* flush workqueue */
 332                if (atomic_read(&lc->sched_flush))
 333                        flush_delayed_work(&lc->flush_log_work);
 334
 335                destroy_workqueue(lc->dmlog_wq);
 336        }
 337
 338        (void) dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_DTR,
 339                                    NULL, 0, NULL, NULL);
 340
 341        if (lc->log_dev)
 342                dm_put_device(lc->ti, lc->log_dev);
 343
 344        mempool_exit(&lc->flush_entry_pool);
 345
 346        kfree(lc->usr_argv_str);
 347        kfree(lc);
 348
 349        return;
 350}
 351
 352static int userspace_presuspend(struct dm_dirty_log *log)
 353{
 354        int r;
 355        struct log_c *lc = log->context;
 356
 357        r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_PRESUSPEND,
 358                                 NULL, 0, NULL, NULL);
 359
 360        return r;
 361}
 362
 363static int userspace_postsuspend(struct dm_dirty_log *log)
 364{
 365        int r;
 366        struct log_c *lc = log->context;
 367
 368        /*
 369         * Run planned flush earlier.
 370         */
 371        if (lc->integrated_flush && atomic_read(&lc->sched_flush))
 372                flush_delayed_work(&lc->flush_log_work);
 373
 374        r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_POSTSUSPEND,
 375                                 NULL, 0, NULL, NULL);
 376
 377        return r;
 378}
 379
 380static int userspace_resume(struct dm_dirty_log *log)
 381{
 382        int r;
 383        struct log_c *lc = log->context;
 384
 385        lc->in_sync_hint = 0;
 386        r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_RESUME,
 387                                 NULL, 0, NULL, NULL);
 388
 389        return r;
 390}
 391
 392static uint32_t userspace_get_region_size(struct dm_dirty_log *log)
 393{
 394        struct log_c *lc = log->context;
 395
 396        return lc->region_size;
 397}
 398
 399/*
 400 * userspace_is_clean
 401 *
 402 * Check whether a region is clean.  If there is any sort of
 403 * failure when consulting the server, we return not clean.
 404 *
 405 * Returns: 1 if clean, 0 otherwise
 406 */
 407static int userspace_is_clean(struct dm_dirty_log *log, region_t region)
 408{
 409        int r;
 410        uint64_t region64 = (uint64_t)region;
 411        int64_t is_clean;
 412        size_t rdata_size;
 413        struct log_c *lc = log->context;
 414
 415        rdata_size = sizeof(is_clean);
 416        r = userspace_do_request(lc, lc->uuid, DM_ULOG_IS_CLEAN,
 417                                 (char *)&region64, sizeof(region64),
 418                                 (char *)&is_clean, &rdata_size);
 419
 420        return (r) ? 0 : (int)is_clean;
 421}
 422
 423/*
 424 * userspace_in_sync
 425 *
 426 * Check if the region is in-sync.  If there is any sort
 427 * of failure when consulting the server, we assume that
 428 * the region is not in sync.
 429 *
 430 * If 'can_block' is set, return immediately
 431 *
 432 * Returns: 1 if in-sync, 0 if not-in-sync, -EWOULDBLOCK
 433 */
 434static int userspace_in_sync(struct dm_dirty_log *log, region_t region,
 435                             int can_block)
 436{
 437        int r;
 438        uint64_t region64 = region;
 439        int64_t in_sync;
 440        size_t rdata_size;
 441        struct log_c *lc = log->context;
 442
 443        /*
 444         * We can never respond directly - even if in_sync_hint is
 445         * set.  This is because another machine could see a device
 446         * failure and mark the region out-of-sync.  If we don't go
 447         * to userspace to ask, we might think the region is in-sync
 448         * and allow a read to pick up data that is stale.  (This is
 449         * very unlikely if a device actually fails; but it is very
 450         * likely if a connection to one device from one machine fails.)
 451         *
 452         * There still might be a problem if the mirror caches the region
 453         * state as in-sync... but then this call would not be made.  So,
 454         * that is a mirror problem.
 455         */
 456        if (!can_block)
 457                return -EWOULDBLOCK;
 458
 459        rdata_size = sizeof(in_sync);
 460        r = userspace_do_request(lc, lc->uuid, DM_ULOG_IN_SYNC,
 461                                 (char *)&region64, sizeof(region64),
 462                                 (char *)&in_sync, &rdata_size);
 463        return (r) ? 0 : (int)in_sync;
 464}
 465
 466static int flush_one_by_one(struct log_c *lc, struct list_head *flush_list)
 467{
 468        int r = 0;
 469        struct dm_dirty_log_flush_entry *fe;
 470
 471        list_for_each_entry(fe, flush_list, list) {
 472                r = userspace_do_request(lc, lc->uuid, fe->type,
 473                                         (char *)&fe->region,
 474                                         sizeof(fe->region),
 475                                         NULL, NULL);
 476                if (r)
 477                        break;
 478        }
 479
 480        return r;
 481}
 482
 483static int flush_by_group(struct log_c *lc, struct list_head *flush_list,
 484                          int flush_with_payload)
 485{
 486        int r = 0;
 487        int count;
 488        uint32_t type = 0;
 489        struct dm_dirty_log_flush_entry *fe, *tmp_fe;
 490        LIST_HEAD(tmp_list);
 491        uint64_t group[MAX_FLUSH_GROUP_COUNT];
 492
 493        /*
 494         * Group process the requests
 495         */
 496        while (!list_empty(flush_list)) {
 497                count = 0;
 498
 499                list_for_each_entry_safe(fe, tmp_fe, flush_list, list) {
 500                        group[count] = fe->region;
 501                        count++;
 502
 503                        list_move(&fe->list, &tmp_list);
 504
 505                        type = fe->type;
 506                        if (count >= MAX_FLUSH_GROUP_COUNT)
 507                                break;
 508                }
 509
 510                if (flush_with_payload) {
 511                        r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
 512                                                 (char *)(group),
 513                                                 count * sizeof(uint64_t),
 514                                                 NULL, NULL);
 515                        /*
 516                         * Integrated flush failed.
 517                         */
 518                        if (r)
 519                                break;
 520                } else {
 521                        r = userspace_do_request(lc, lc->uuid, type,
 522                                                 (char *)(group),
 523                                                 count * sizeof(uint64_t),
 524                                                 NULL, NULL);
 525                        if (r) {
 526                                /*
 527                                 * Group send failed.  Attempt one-by-one.
 528                                 */
 529                                list_splice_init(&tmp_list, flush_list);
 530                                r = flush_one_by_one(lc, flush_list);
 531                                break;
 532                        }
 533                }
 534        }
 535
 536        /*
 537         * Must collect flush_entrys that were successfully processed
 538         * as a group so that they will be free'd by the caller.
 539         */
 540        list_splice_init(&tmp_list, flush_list);
 541
 542        return r;
 543}
 544
 545/*
 546 * userspace_flush
 547 *
 548 * This function is ok to block.
 549 * The flush happens in two stages.  First, it sends all
 550 * clear/mark requests that are on the list.  Then it
 551 * tells the server to commit them.  This gives the
 552 * server a chance to optimise the commit, instead of
 553 * doing it for every request.
 554 *
 555 * Additionally, we could implement another thread that
 556 * sends the requests up to the server - reducing the
 557 * load on flush.  Then the flush would have less in
 558 * the list and be responsible for the finishing commit.
 559 *
 560 * Returns: 0 on success, < 0 on failure
 561 */
 562static int userspace_flush(struct dm_dirty_log *log)
 563{
 564        int r = 0;
 565        unsigned long flags;
 566        struct log_c *lc = log->context;
 567        LIST_HEAD(mark_list);
 568        LIST_HEAD(clear_list);
 569        int mark_list_is_empty;
 570        int clear_list_is_empty;
 571        struct dm_dirty_log_flush_entry *fe, *tmp_fe;
 572        mempool_t *flush_entry_pool = &lc->flush_entry_pool;
 573
 574        spin_lock_irqsave(&lc->flush_lock, flags);
 575        list_splice_init(&lc->mark_list, &mark_list);
 576        list_splice_init(&lc->clear_list, &clear_list);
 577        spin_unlock_irqrestore(&lc->flush_lock, flags);
 578
 579        mark_list_is_empty = list_empty(&mark_list);
 580        clear_list_is_empty = list_empty(&clear_list);
 581
 582        if (mark_list_is_empty && clear_list_is_empty)
 583                return 0;
 584
 585        r = flush_by_group(lc, &clear_list, 0);
 586        if (r)
 587                goto out;
 588
 589        if (!lc->integrated_flush) {
 590                r = flush_by_group(lc, &mark_list, 0);
 591                if (r)
 592                        goto out;
 593                r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
 594                                         NULL, 0, NULL, NULL);
 595                goto out;
 596        }
 597
 598        /*
 599         * Send integrated flush request with mark_list as payload.
 600         */
 601        r = flush_by_group(lc, &mark_list, 1);
 602        if (r)
 603                goto out;
 604
 605        if (mark_list_is_empty && !atomic_read(&lc->sched_flush)) {
 606                /*
 607                 * When there are only clear region requests,
 608                 * we schedule a flush in the future.
 609                 */
 610                queue_delayed_work(lc->dmlog_wq, &lc->flush_log_work, 3 * HZ);
 611                atomic_set(&lc->sched_flush, 1);
 612        } else {
 613                /*
 614                 * Cancel pending flush because we
 615                 * have already flushed in mark_region.
 616                 */
 617                cancel_delayed_work(&lc->flush_log_work);
 618                atomic_set(&lc->sched_flush, 0);
 619        }
 620
 621out:
 622        /*
 623         * We can safely remove these entries, even after failure.
 624         * Calling code will receive an error and will know that
 625         * the log facility has failed.
 626         */
 627        list_for_each_entry_safe(fe, tmp_fe, &mark_list, list) {
 628                list_del(&fe->list);
 629                mempool_free(fe, flush_entry_pool);
 630        }
 631        list_for_each_entry_safe(fe, tmp_fe, &clear_list, list) {
 632                list_del(&fe->list);
 633                mempool_free(fe, flush_entry_pool);
 634        }
 635
 636        if (r)
 637                dm_table_event(lc->ti->table);
 638
 639        return r;
 640}
 641
 642/*
 643 * userspace_mark_region
 644 *
 645 * This function should avoid blocking unless absolutely required.
 646 * (Memory allocation is valid for blocking.)
 647 */
 648static void userspace_mark_region(struct dm_dirty_log *log, region_t region)
 649{
 650        unsigned long flags;
 651        struct log_c *lc = log->context;
 652        struct dm_dirty_log_flush_entry *fe;
 653
 654        /* Wait for an allocation, but _never_ fail */
 655        fe = mempool_alloc(&lc->flush_entry_pool, GFP_NOIO);
 656        BUG_ON(!fe);
 657
 658        spin_lock_irqsave(&lc->flush_lock, flags);
 659        fe->type = DM_ULOG_MARK_REGION;
 660        fe->region = region;
 661        list_add(&fe->list, &lc->mark_list);
 662        spin_unlock_irqrestore(&lc->flush_lock, flags);
 663
 664        return;
 665}
 666
 667/*
 668 * userspace_clear_region
 669 *
 670 * This function must not block.
 671 * So, the alloc can't block.  In the worst case, it is ok to
 672 * fail.  It would simply mean we can't clear the region.
 673 * Does nothing to current sync context, but does mean
 674 * the region will be re-sync'ed on a reload of the mirror
 675 * even though it is in-sync.
 676 */
 677static void userspace_clear_region(struct dm_dirty_log *log, region_t region)
 678{
 679        unsigned long flags;
 680        struct log_c *lc = log->context;
 681        struct dm_dirty_log_flush_entry *fe;
 682
 683        /*
 684         * If we fail to allocate, we skip the clearing of
 685         * the region.  This doesn't hurt us in any way, except
 686         * to cause the region to be resync'ed when the
 687         * device is activated next time.
 688         */
 689        fe = mempool_alloc(&lc->flush_entry_pool, GFP_ATOMIC);
 690        if (!fe) {
 691                DMERR("Failed to allocate memory to clear region.");
 692                return;
 693        }
 694
 695        spin_lock_irqsave(&lc->flush_lock, flags);
 696        fe->type = DM_ULOG_CLEAR_REGION;
 697        fe->region = region;
 698        list_add(&fe->list, &lc->clear_list);
 699        spin_unlock_irqrestore(&lc->flush_lock, flags);
 700
 701        return;
 702}
 703
 704/*
 705 * userspace_get_resync_work
 706 *
 707 * Get a region that needs recovery.  It is valid to return
 708 * an error for this function.
 709 *
 710 * Returns: 1 if region filled, 0 if no work, <0 on error
 711 */
 712static int userspace_get_resync_work(struct dm_dirty_log *log, region_t *region)
 713{
 714        int r;
 715        size_t rdata_size;
 716        struct log_c *lc = log->context;
 717        struct {
 718                int64_t i; /* 64-bit for mix arch compatibility */
 719                region_t r;
 720        } pkg;
 721
 722        if (lc->in_sync_hint >= lc->region_count)
 723                return 0;
 724
 725        rdata_size = sizeof(pkg);
 726        r = userspace_do_request(lc, lc->uuid, DM_ULOG_GET_RESYNC_WORK,
 727                                 NULL, 0, (char *)&pkg, &rdata_size);
 728
 729        *region = pkg.r;
 730        return (r) ? r : (int)pkg.i;
 731}
 732
 733/*
 734 * userspace_set_region_sync
 735 *
 736 * Set the sync status of a given region.  This function
 737 * must not fail.
 738 */
 739static void userspace_set_region_sync(struct dm_dirty_log *log,
 740                                      region_t region, int in_sync)
 741{
 742        struct log_c *lc = log->context;
 743        struct {
 744                region_t r;
 745                int64_t i;
 746        } pkg;
 747
 748        pkg.r = region;
 749        pkg.i = (int64_t)in_sync;
 750
 751        (void) userspace_do_request(lc, lc->uuid, DM_ULOG_SET_REGION_SYNC,
 752                                    (char *)&pkg, sizeof(pkg), NULL, NULL);
 753
 754        /*
 755         * It would be nice to be able to report failures.
 756         * However, it is easy enough to detect and resolve.
 757         */
 758        return;
 759}
 760
 761/*
 762 * userspace_get_sync_count
 763 *
 764 * If there is any sort of failure when consulting the server,
 765 * we assume that the sync count is zero.
 766 *
 767 * Returns: sync count on success, 0 on failure
 768 */
 769static region_t userspace_get_sync_count(struct dm_dirty_log *log)
 770{
 771        int r;
 772        size_t rdata_size;
 773        uint64_t sync_count;
 774        struct log_c *lc = log->context;
 775
 776        rdata_size = sizeof(sync_count);
 777        r = userspace_do_request(lc, lc->uuid, DM_ULOG_GET_SYNC_COUNT,
 778                                 NULL, 0, (char *)&sync_count, &rdata_size);
 779
 780        if (r)
 781                return 0;
 782
 783        if (sync_count >= lc->region_count)
 784                lc->in_sync_hint = lc->region_count;
 785
 786        return (region_t)sync_count;
 787}
 788
 789/*
 790 * userspace_status
 791 *
 792 * Returns: amount of space consumed
 793 */
 794static int userspace_status(struct dm_dirty_log *log, status_type_t status_type,
 795                            char *result, unsigned maxlen)
 796{
 797        int r = 0;
 798        char *table_args;
 799        size_t sz = (size_t)maxlen;
 800        struct log_c *lc = log->context;
 801
 802        switch (status_type) {
 803        case STATUSTYPE_INFO:
 804                r = userspace_do_request(lc, lc->uuid, DM_ULOG_STATUS_INFO,
 805                                         NULL, 0, result, &sz);
 806
 807                if (r) {
 808                        sz = 0;
 809                        DMEMIT("%s 1 COM_FAILURE", log->type->name);
 810                }
 811                break;
 812        case STATUSTYPE_TABLE:
 813                sz = 0;
 814                table_args = strchr(lc->usr_argv_str, ' ');
 815                BUG_ON(!table_args); /* There will always be a ' ' */
 816                table_args++;
 817
 818                DMEMIT("%s %u %s ", log->type->name, lc->usr_argc, lc->uuid);
 819                if (lc->integrated_flush)
 820                        DMEMIT("integrated_flush ");
 821                DMEMIT("%s ", table_args);
 822                break;
 823        }
 824        return (r) ? 0 : (int)sz;
 825}
 826
 827/*
 828 * userspace_is_remote_recovering
 829 *
 830 * Returns: 1 if region recovering, 0 otherwise
 831 */
 832static int userspace_is_remote_recovering(struct dm_dirty_log *log,
 833                                          region_t region)
 834{
 835        int r;
 836        uint64_t region64 = region;
 837        struct log_c *lc = log->context;
 838        static unsigned long limit;
 839        struct {
 840                int64_t is_recovering;
 841                uint64_t in_sync_hint;
 842        } pkg;
 843        size_t rdata_size = sizeof(pkg);
 844
 845        /*
 846         * Once the mirror has been reported to be in-sync,
 847         * it will never again ask for recovery work.  So,
 848         * we can safely say there is not a remote machine
 849         * recovering if the device is in-sync.  (in_sync_hint
 850         * must be reset at resume time.)
 851         */
 852        if (region < lc->in_sync_hint)
 853                return 0;
 854        else if (time_after(limit, jiffies))
 855                return 1;
 856
 857        limit = jiffies + (HZ / 4);
 858        r = userspace_do_request(lc, lc->uuid, DM_ULOG_IS_REMOTE_RECOVERING,
 859                                 (char *)&region64, sizeof(region64),
 860                                 (char *)&pkg, &rdata_size);
 861        if (r)
 862                return 1;
 863
 864        lc->in_sync_hint = pkg.in_sync_hint;
 865
 866        return (int)pkg.is_recovering;
 867}
 868
 869static struct dm_dirty_log_type _userspace_type = {
 870        .name = "userspace",
 871        .module = THIS_MODULE,
 872        .ctr = userspace_ctr,
 873        .dtr = userspace_dtr,
 874        .presuspend = userspace_presuspend,
 875        .postsuspend = userspace_postsuspend,
 876        .resume = userspace_resume,
 877        .get_region_size = userspace_get_region_size,
 878        .is_clean = userspace_is_clean,
 879        .in_sync = userspace_in_sync,
 880        .flush = userspace_flush,
 881        .mark_region = userspace_mark_region,
 882        .clear_region = userspace_clear_region,
 883        .get_resync_work = userspace_get_resync_work,
 884        .set_region_sync = userspace_set_region_sync,
 885        .get_sync_count = userspace_get_sync_count,
 886        .status = userspace_status,
 887        .is_remote_recovering = userspace_is_remote_recovering,
 888};
 889
 890static int __init userspace_dirty_log_init(void)
 891{
 892        int r = 0;
 893
 894        _flush_entry_cache = KMEM_CACHE(dm_dirty_log_flush_entry, 0);
 895        if (!_flush_entry_cache) {
 896                DMWARN("Unable to create flush_entry_cache: No memory.");
 897                return -ENOMEM;
 898        }
 899
 900        r = dm_ulog_tfr_init();
 901        if (r) {
 902                DMWARN("Unable to initialize userspace log communications");
 903                kmem_cache_destroy(_flush_entry_cache);
 904                return r;
 905        }
 906
 907        r = dm_dirty_log_type_register(&_userspace_type);
 908        if (r) {
 909                DMWARN("Couldn't register userspace dirty log type");
 910                dm_ulog_tfr_exit();
 911                kmem_cache_destroy(_flush_entry_cache);
 912                return r;
 913        }
 914
 915        DMINFO("version " DM_LOG_USERSPACE_VSN " loaded");
 916        return 0;
 917}
 918
 919static void __exit userspace_dirty_log_exit(void)
 920{
 921        dm_dirty_log_type_unregister(&_userspace_type);
 922        dm_ulog_tfr_exit();
 923        kmem_cache_destroy(_flush_entry_cache);
 924
 925        DMINFO("version " DM_LOG_USERSPACE_VSN " unloaded");
 926        return;
 927}
 928
 929module_init(userspace_dirty_log_init);
 930module_exit(userspace_dirty_log_exit);
 931
 932MODULE_DESCRIPTION(DM_NAME " userspace dirty log link");
 933MODULE_AUTHOR("Jonathan Brassow <dm-devel@redhat.com>");
 934MODULE_LICENSE("GPL");
 935