fs/xfs/xfs_log.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   4  * All Rights Reserved.
   5  */
   6 #include "xfs.h"
   7 #include "xfs_fs.h"
   8 #include "xfs_shared.h"
   9 #include "xfs_format.h"
  10 #include "xfs_log_format.h"
  11 #include "xfs_trans_resv.h"
  12 #include "xfs_mount.h"
  13 #include "xfs_errortag.h"
  14 #include "xfs_error.h"
  15 #include "xfs_trans.h"
  16 #include "xfs_trans_priv.h"
  17 #include "xfs_log.h"
  18 #include "xfs_log_priv.h"
  19 #include "xfs_trace.h"
  20 #include "xfs_sysfs.h"
  21 #include "xfs_sb.h"
  22 #include "xfs_health.h"
  23
  24 kmem_zone_t     *xfs_log_ticket_zone;
  25
  26 /* Local miscellaneous function prototypes */
  27 STATIC int
  28 xlog_commit_record(
  29         struct xlog             *log,
  30         struct xlog_ticket      *ticket,
  31         struct xlog_in_core     **iclog,
  32         xfs_lsn_t               *commitlsnp);
  33
  34 STATIC struct xlog *
  35 xlog_alloc_log(
  36         struct xfs_mount        *mp,
  37         struct xfs_buftarg      *log_target,
  38         xfs_daddr_t             blk_offset,
  39         int                     num_bblks);
  40 STATIC int
  41 xlog_space_left(
  42         struct xlog             *log,
  43         atomic64_t              *head);
  44 STATIC void
  45 xlog_dealloc_log(
  46         struct xlog             *log);
  47
  48 /* local state machine functions */
  49 STATIC void xlog_state_done_syncing(
  50         struct xlog_in_core     *iclog,
  51         bool                    aborted);
  52 STATIC int
  53 xlog_state_get_iclog_space(
  54         struct xlog             *log,
  55         int                     len,
  56         struct xlog_in_core     **iclog,
  57         struct xlog_ticket      *ticket,
  58         int                     *continued_write,
  59         int                     *logoffsetp);
  60 STATIC int
  61 xlog_state_release_iclog(
  62         struct xlog             *log,
  63         struct xlog_in_core     *iclog);
  64 STATIC void
  65 xlog_state_switch_iclogs(
  66         struct xlog             *log,
  67         struct xlog_in_core     *iclog,
  68         int                     eventual_size);
  69 STATIC void
  70 xlog_state_want_sync(
  71         struct xlog             *log,
  72         struct xlog_in_core     *iclog);
  73
  74 STATIC void
  75 xlog_grant_push_ail(
  76         struct xlog             *log,
  77         int                     need_bytes);
  78 STATIC void
  79 xlog_regrant_reserve_log_space(
  80         struct xlog             *log,
  81         struct xlog_ticket      *ticket);
  82 STATIC void
  83 xlog_ungrant_log_space(
  84         struct xlog             *log,
  85         struct xlog_ticket      *ticket);
  86
  87 #if defined(DEBUG)
  88 STATIC void
  89 xlog_verify_dest_ptr(
  90         struct xlog             *log,
  91         void                    *ptr);
  92 STATIC void
  93 xlog_verify_grant_tail(
  94         struct xlog *log);
  95 STATIC void
  96 xlog_verify_iclog(
  97         struct xlog             *log,
  98         struct xlog_in_core     *iclog,
  99         int                     count);
 100 STATIC void
 101 xlog_verify_tail_lsn(
 102         struct xlog             *log,
 103         struct xlog_in_core     *iclog,
 104         xfs_lsn_t               tail_lsn);
 105 #else
 106 #define xlog_verify_dest_ptr(a,b)
 107 #define xlog_verify_grant_tail(a)
 108 #define xlog_verify_iclog(a,b,c)
 109 #define xlog_verify_tail_lsn(a,b,c)
 110 #endif
 111
 112 STATIC int
 113 xlog_iclogs_empty(
 114         struct xlog             *log);
 115
 116 static void
 117 xlog_grant_sub_space(
 118         struct xlog             *log,
 119         atomic64_t              *head,
 120         int                     bytes)
 121 {
 122         int64_t head_val = atomic64_read(head);
 123         int64_t new, old;
 124
 125         do {
 126                 int     cycle, space;
 127
 128                 xlog_crack_grant_head_val(head_val, &cycle, &space);
 129
 130                 space -= bytes;
 131                 if (space < 0) {
 132                         space += log->l_logsize;
 133                         cycle--;
 134                 }
 135
 136                 old = head_val;
 137                 new = xlog_assign_grant_head_val(cycle, space);
 138                 head_val = atomic64_cmpxchg(head, old, new);
 139         } while (head_val != old);
 140 }
 141
 142 static void
 143 xlog_grant_add_space(
 144         struct xlog             *log,
 145         atomic64_t              *head,
 146         int                     bytes)
 147 {
 148         int64_t head_val = atomic64_read(head);
 149         int64_t new, old;
 150
 151         do {
 152                 int             tmp;
 153                 int             cycle, space;
 154
 155                 xlog_crack_grant_head_val(head_val, &cycle, &space);
 156
 157                 tmp = log->l_logsize - space;
 158                 if (tmp > bytes)
 159                         space += bytes;
 160                 else {
 161                         space = bytes - tmp;
 162                         cycle++;
 163                 }
 164
 165                 old = head_val;
 166                 new = xlog_assign_grant_head_val(cycle, space);
 167                 head_val = atomic64_cmpxchg(head, old, new);
 168         } while (head_val != old);
 169 }
 170
 171 STATIC void
 172 xlog_grant_head_init(
 173         struct xlog_grant_head  *head)
 174 {
 175         xlog_assign_grant_head(&head->grant, 1, 0);
 176         INIT_LIST_HEAD(&head->waiters);
 177         spin_lock_init(&head->lock);
 178 }
 179
 180 STATIC void
 181 xlog_grant_head_wake_all(
 182         struct xlog_grant_head  *head)
 183 {
 184         struct xlog_ticket      *tic;
 185
 186         spin_lock(&head->lock);
 187         list_for_each_entry(tic, &head->waiters, t_queue)
 188                 wake_up_process(tic->t_task);
 189         spin_unlock(&head->lock);
 190 }
 191
 192 static inline int
 193 xlog_ticket_reservation(
 194         struct xlog             *log,
 195         struct xlog_grant_head  *head,
 196         struct xlog_ticket      *tic)
 197 {
 198         if (head == &log->l_write_head) {
 199                 ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
 200                 return tic->t_unit_res;
 201         } else {
 202                 if (tic->t_flags & XLOG_TIC_PERM_RESERV)
 203                         return tic->t_unit_res * tic->t_cnt;
 204                 else
 205                         return tic->t_unit_res;
 206         }
 207 }
 208
 209 STATIC bool
 210 xlog_grant_head_wake(
 211         struct xlog             *log,
 212         struct xlog_grant_head  *head,
 213         int                     *free_bytes)
 214 {
 215         struct xlog_ticket      *tic;
 216         int                     need_bytes;
 217
 218         list_for_each_entry(tic, &head->waiters, t_queue) {
 219                 need_bytes = xlog_ticket_reservation(log, head, tic);
 220                 if (*free_bytes < need_bytes)
 221                         return false;
 222
 223                 *free_bytes -= need_bytes;
 224                 trace_xfs_log_grant_wake_up(log, tic);
 225                 wake_up_process(tic->t_task);
 226         }
 227
 228         return true;
 229 }
 230
 231 STATIC int
 232 xlog_grant_head_wait(
 233         struct xlog             *log,
 234         struct xlog_grant_head  *head,
 235         struct xlog_ticket      *tic,
 236         int                     need_bytes) __releases(&head->lock)
 237                                             __acquires(&head->lock)
 238 {
 239         list_add_tail(&tic->t_queue, &head->waiters);
 240
 241         do {
 242                 if (XLOG_FORCED_SHUTDOWN(log))
 243                         goto shutdown;
 244                 xlog_grant_push_ail(log, need_bytes);
 245
 246                 __set_current_state(TASK_UNINTERRUPTIBLE);
 247                 spin_unlock(&head->lock);
 248
 249                 XFS_STATS_INC(log->l_mp, xs_sleep_logspace);
 250
 251                 trace_xfs_log_grant_sleep(log, tic);
 252                 schedule();
 253                 trace_xfs_log_grant_wake(log, tic);
 254
 255                 spin_lock(&head->lock);
 256                 if (XLOG_FORCED_SHUTDOWN(log))
 257                         goto shutdown;
 258         } while (xlog_space_left(log, &head->grant) < need_bytes);
 259
 260         list_del_init(&tic->t_queue);
 261         return 0;
 262 shutdown:
 263         list_del_init(&tic->t_queue);
 264         return -EIO;
 265 }
 266
 267 /*
 268  * Atomically get the log space required for a log ticket.
 269  *
 270  * Once a ticket gets put onto head->waiters, it will only return after the
 271  * needed reservation is satisfied.
 272  *
 273  * This function is structured so that it has a lock free fast path. This is
 274  * necessary because every new transaction reservation will come through this
 275  * path. Hence any lock will be globally hot if we take it unconditionally on
 276  * every pass.
 277  *
 278  * As tickets are only ever moved on and off head->waiters under head->lock, we
 279  * only need to take that lock if we are going to add the ticket to the queue
 280  * and sleep. We can avoid taking the lock if the ticket was never added to
 281  * head->waiters because the t_queue list head will be empty and we hold the
 282  * only reference to it so it can safely be checked unlocked.
 283  */
 284 STATIC int
 285 xlog_grant_head_check(
 286         struct xlog             *log,
 287         struct xlog_grant_head  *head,
 288         struct xlog_ticket      *tic,
 289         int                     *need_bytes)
 290 {
 291         int                     free_bytes;
 292         int                     error = 0;
 293
 294         ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
 295
 296         /*
 297          * If there are other waiters on the queue then give them a chance at
 298          * logspace before us.  Wake up the first waiters, if we do not wake
 299          * up all the waiters then go to sleep waiting for more free space,
 300          * otherwise try to get some space for this transaction.
 301          */
 302         *need_bytes = xlog_ticket_reservation(log, head, tic);
 303         free_bytes = xlog_space_left(log, &head->grant);
 304         if (!list_empty_careful(&head->waiters)) {
 305                 spin_lock(&head->lock);
 306                 if (!xlog_grant_head_wake(log, head, &free_bytes) ||
 307                     free_bytes < *need_bytes) {
 308                         error = xlog_grant_head_wait(log, head, tic,
 309                                                      *need_bytes);
 310                 }
 311                 spin_unlock(&head->lock);
 312         } else if (free_bytes < *need_bytes) {
 313                 spin_lock(&head->lock);
 314                 error = xlog_grant_head_wait(log, head, tic, *need_bytes);
 315                 spin_unlock(&head->lock);
 316         }
 317
 318         return error;
 319 }
 320
 321 static void
 322 xlog_tic_reset_res(xlog_ticket_t *tic)
 323 {
 324         tic->t_res_num = 0;
 325         tic->t_res_arr_sum = 0;
 326         tic->t_res_num_ophdrs = 0;
 327 }
 328
 329 static void
 330 xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type)
 331 {
 332         if (tic->t_res_num == XLOG_TIC_LEN_MAX) {
 333                 /* add to overflow and start again */
 334                 tic->t_res_o_flow += tic->t_res_arr_sum;
 335                 tic->t_res_num = 0;
 336                 tic->t_res_arr_sum = 0;
 337         }
 338
 339         tic->t_res_arr[tic->t_res_num].r_len = len;
 340         tic->t_res_arr[tic->t_res_num].r_type = type;
 341         tic->t_res_arr_sum += len;
 342         tic->t_res_num++;
 343 }
 344
 345 /*
 346  * Replenish the byte reservation required by moving the grant write head.
 347  */
 348 int
 349 xfs_log_regrant(
 350         struct xfs_mount        *mp,
 351         struct xlog_ticket      *tic)
 352 {
 353         struct xlog             *log = mp->m_log;
 354         int                     need_bytes;
 355         int                     error = 0;
 356
 357         if (XLOG_FORCED_SHUTDOWN(log))
 358                 return -EIO;
 359
 360         XFS_STATS_INC(mp, xs_try_logspace);
 361
 362         /*
 363          * This is a new transaction on the ticket, so we need to change the
 364          * transaction ID so that the next transaction has a different TID in
 365          * the log. Just add one to the existing tid so that we can see chains
 366          * of rolling transactions in the log easily.
 367          */
 368         tic->t_tid++;
 369
 370         xlog_grant_push_ail(log, tic->t_unit_res);
 371
 372         tic->t_curr_res = tic->t_unit_res;
 373         xlog_tic_reset_res(tic);
 374
 375         if (tic->t_cnt > 0)
 376                 return 0;
 377
 378         trace_xfs_log_regrant(log, tic);
 379
 380         error = xlog_grant_head_check(log, &log->l_write_head, tic,
 381                                       &need_bytes);
 382         if (error)
 383                 goto out_error;
 384
 385         xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
 386         trace_xfs_log_regrant_exit(log, tic);
 387         xlog_verify_grant_tail(log);
 388         return 0;
 389
 390 out_error:
 391         /*
 392          * If we are failing, make sure the ticket doesn't have any current
 393          * reservations.  We don't want to add this back when the ticket/
 394          * transaction gets cancelled.
 395          */
 396         tic->t_curr_res = 0;
 397         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
 398         return error;
 399 }
 400
 401 /*
 402  * Reserve log space and return a ticket corresponding to the reservation.
 403  *
 404  * Each reservation is going to reserve extra space for a log record header.
 405  * When writes happen to the on-disk log, we don't subtract the length of the
 406  * log record header from any reservation.  By wasting space in each
 407  * reservation, we prevent over allocation problems.
 408  */
 409 int
 410 xfs_log_reserve(
 411         struct xfs_mount        *mp,
 412         int                     unit_bytes,
 413         int                     cnt,
 414         struct xlog_ticket      **ticp,
 415         uint8_t                 client,
 416         bool                    permanent)
 417 {
 418         struct xlog             *log = mp->m_log;
 419         struct xlog_ticket      *tic;
 420         int                     need_bytes;
 421         int                     error = 0;
 422
 423         ASSERT(client == XFS_TRANSACTION || client == XFS_LOG);
 424
 425         if (XLOG_FORCED_SHUTDOWN(log))
 426                 return -EIO;
 427
 428         XFS_STATS_INC(mp, xs_try_logspace);
 429
 430         ASSERT(*ticp == NULL);
 431         tic = xlog_ticket_alloc(log, unit_bytes, cnt, client, permanent,
 432                                 KM_SLEEP | KM_MAYFAIL);
 433         if (!tic)
 434                 return -ENOMEM;
 435
 436         *ticp = tic;
 437
 438         xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt
 439                                             : tic->t_unit_res);
 440
 441         trace_xfs_log_reserve(log, tic);
 442
 443         error = xlog_grant_head_check(log, &log->l_reserve_head, tic,
 444                                       &need_bytes);
 445         if (error)
 446                 goto out_error;
 447
 448         xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes);
 449         xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
 450         trace_xfs_log_reserve_exit(log, tic);
 451         xlog_verify_grant_tail(log);
 452         return 0;
 453
 454 out_error:
 455         /*
 456          * If we are failing, make sure the ticket doesn't have any current
 457          * reservations.  We don't want to add this back when the ticket/
 458          * transaction gets cancelled.
 459          */
 460         tic->t_curr_res = 0;
 461         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
 462         return error;
 463 }
 464
 465
 466 /*
 467  * NOTES:
 468  *
 469  *      1. currblock field gets updated at startup and after in-core logs
 470  *              marked as with WANT_SYNC.
 471  */
 472
 473 /*
 474  * This routine is called when a user of a log manager ticket is done with
 475  * the reservation.  If the ticket was ever used, then a commit record for
 476  * the associated transaction is written out as a log operation header with
 477  * no data.  The flag XLOG_TIC_INITED is set when the first write occurs with
 478  * a given ticket.  If the ticket was one with a permanent reservation, then
 479  * a few operations are done differently.  Permanent reservation tickets by
 480  * default don't release the reservation.  They just commit the current
 481  * transaction with the belief that the reservation is still needed.  A flag
 482  * must be passed in before permanent reservations are actually released.
 483  * When these type of tickets are not released, they need to be set into
 484  * the inited state again.  By doing this, a start record will be written
 485  * out when the next write occurs.
 486  */
 487 xfs_lsn_t
 488 xfs_log_done(
 489         struct xfs_mount        *mp,
 490         struct xlog_ticket      *ticket,
 491         struct xlog_in_core     **iclog,
 492         bool                    regrant)
 493 {
 494         struct xlog             *log = mp->m_log;
 495         xfs_lsn_t               lsn = 0;
 496
 497         if (XLOG_FORCED_SHUTDOWN(log) ||
 498             /*
 499              * If nothing was ever written, don't write out commit record.
 500              * If we get an error, just continue and give back the log ticket.
 501              */
 502             (((ticket->t_flags & XLOG_TIC_INITED) == 0) &&
 503              (xlog_commit_record(log, ticket, iclog, &lsn)))) {
 504                 lsn = (xfs_lsn_t) -1;
 505                 regrant = false;
 506         }
 507
 508
 509         if (!regrant) {
 510                 trace_xfs_log_done_nonperm(log, ticket);
 511
 512                 /*
 513                  * Release ticket if not permanent reservation or a specific
 514                  * request has been made to release a permanent reservation.
 515                  */
 516                 xlog_ungrant_log_space(log, ticket);
 517         } else {
 518                 trace_xfs_log_done_perm(log, ticket);
 519
 520                 xlog_regrant_reserve_log_space(log, ticket);
 521                 /* If this ticket was a permanent reservation and we aren't
 522                  * trying to release it, reset the inited flags; so next time
 523                  * we write, a start record will be written out.
 524                  */
 525                 ticket->t_flags |= XLOG_TIC_INITED;
 526         }
 527
 528         xfs_log_ticket_put(ticket);
 529         return lsn;
 530 }
 531
 532 int
 533 xfs_log_release_iclog(
 534         struct xfs_mount        *mp,
 535         struct xlog_in_core     *iclog)
 536 {
 537         if (xlog_state_release_iclog(mp->m_log, iclog)) {
 538                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
 539                 return -EIO;
 540         }
 541
 542         return 0;
 543 }
 544
 545 /*
 546  * Mount a log filesystem
 547  *
 548  * mp           - ubiquitous xfs mount point structure
 549  * log_target   - buftarg of on-disk log device
 550  * blk_offset   - Start block # where block size is 512 bytes (BBSIZE)
 551  * num_bblocks  - Number of BBSIZE blocks in on-disk log
 552  *
 553  * Return error or zero.
 554  */
 555 int
 556 xfs_log_mount(
 557         xfs_mount_t     *mp,
 558         xfs_buftarg_t   *log_target,
 559         xfs_daddr_t     blk_offset,
 560         int             num_bblks)
 561 {
 562         bool            fatal = xfs_sb_version_hascrc(&mp->m_sb);
 563         int             error = 0;
 564         int             min_logfsbs;
 565
 566         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
 567                 xfs_notice(mp, "Mounting V%d Filesystem",
 568                            XFS_SB_VERSION_NUM(&mp->m_sb));
 569         } else {
 570                 xfs_notice(mp,
 571 "Mounting V%d filesystem in no-recovery mode. Filesystem will be inconsistent.",
 572                            XFS_SB_VERSION_NUM(&mp->m_sb));
 573                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 574         }
 575
 576         mp->m_log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
 577         if (IS_ERR(mp->m_log)) {
 578                 error = PTR_ERR(mp->m_log);
 579                 goto out;
 580         }
 581
 582         /*
 583          * Validate the given log space and drop a critical message via syslog
 584          * if the log size is too small that would lead to some unexpected
 585          * situations in transaction log space reservation stage.
 586          *
 587          * Note: we can't just reject the mount if the validation fails.  This
 588          * would mean that people would have to downgrade their kernel just to
 589          * remedy the situation as there is no way to grow the log (short of
 590          * black magic surgery with xfs_db).
 591          *
 592          * We can, however, reject mounts for CRC format filesystems, as the
 593          * mkfs binary being used to make the filesystem should never create a
 594          * filesystem with a log that is too small.
 595          */
 596         min_logfsbs = xfs_log_calc_minimum_size(mp);
 597
 598         if (mp->m_sb.sb_logblocks < min_logfsbs) {
 599                 xfs_warn(mp,
 600                 "Log size %d blocks too small, minimum size is %d blocks",
 601                          mp->m_sb.sb_logblocks, min_logfsbs);
 602                 error = -EINVAL;
 603         } else if (mp->m_sb.sb_logblocks > XFS_MAX_LOG_BLOCKS) {
 604                 xfs_warn(mp,
 605                 "Log size %d blocks too large, maximum size is %lld blocks",
 606                          mp->m_sb.sb_logblocks, XFS_MAX_LOG_BLOCKS);
 607                 error = -EINVAL;
 608         } else if (XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks) > XFS_MAX_LOG_BYTES) {
 609                 xfs_warn(mp,
 610                 "log size %lld bytes too large, maximum size is %lld bytes",
 611                          XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks),
 612                          XFS_MAX_LOG_BYTES);
 613                 error = -EINVAL;
 614         } else if (mp->m_sb.sb_logsunit > 1 &&
 615                    mp->m_sb.sb_logsunit % mp->m_sb.sb_blocksize) {
 616                 xfs_warn(mp,
 617                 "log stripe unit %u bytes must be a multiple of block size",
 618                          mp->m_sb.sb_logsunit);
 619                 error = -EINVAL;
 620                 fatal = true;
 621         }
 622         if (error) {
 623                 /*
 624                  * Log check errors are always fatal on v5; or whenever bad
 625                  * metadata leads to a crash.
 626                  */
 627                 if (fatal) {
 628                         xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
 629                         ASSERT(0);
 630                         goto out_free_log;
 631                 }
 632                 xfs_crit(mp, "Log size out of supported range.");
 633                 xfs_crit(mp,
 634 "Continuing onwards, but if log hangs are experienced then please report this message in the bug report.");
 635         }
 636
 637         /*
 638          * Initialize the AIL now we have a log.
 639          */
 640         error = xfs_trans_ail_init(mp);
 641         if (error) {
 642                 xfs_warn(mp, "AIL initialisation failed: error %d", error);
 643                 goto out_free_log;
 644         }
 645         mp->m_log->l_ailp = mp->m_ail;
 646
 647         /*
 648          * skip log recovery on a norecovery mount.  pretend it all
 649          * just worked.
 650          */
 651         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
 652                 int     readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
 653
 654                 if (readonly)
 655                         mp->m_flags &= ~XFS_MOUNT_RDONLY;
 656
 657                 error = xlog_recover(mp->m_log);
 658
 659                 if (readonly)
 660                         mp->m_flags |= XFS_MOUNT_RDONLY;
 661                 if (error) {
 662                         xfs_warn(mp, "log mount/recovery failed: error %d",
 663                                 error);
 664                         xlog_recover_cancel(mp->m_log);
 665                         goto out_destroy_ail;
 666                 }
 667         }
 668
 669         error = xfs_sysfs_init(&mp->m_log->l_kobj, &xfs_log_ktype, &mp->m_kobj,
 670                                "log");
 671         if (error)
 672                 goto out_destroy_ail;
 673
 674         /* Normal transactions can now occur */
 675         mp->m_log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
 676
 677         /*
 678          * Now the log has been fully initialised and we know were our
 679          * space grant counters are, we can initialise the permanent ticket
 680          * needed for delayed logging to work.
 681          */
 682         xlog_cil_init_post_recovery(mp->m_log);
 683
 684         return 0;
 685
 686 out_destroy_ail:
 687         xfs_trans_ail_destroy(mp);
 688 out_free_log:
 689         xlog_dealloc_log(mp->m_log);
 690 out:
 691         return error;
 692 }
 693
 694 /*
 695  * Finish the recovery of the file system.  This is separate from the
 696  * xfs_log_mount() call, because it depends on the code in xfs_mountfs() to read
 697  * in the root and real-time bitmap inodes between calling xfs_log_mount() and
 698  * here.
 699  *
 700  * If we finish recovery successfully, start the background log work. If we are
 701  * not doing recovery, then we have a RO filesystem and we don't need to start
 702  * it.
 703  */
 704 int
 705 xfs_log_mount_finish(
 706         struct xfs_mount        *mp)
 707 {
 708         int     error = 0;
 709         bool    readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
 710         bool    recovered = mp->m_log->l_flags & XLOG_RECOVERY_NEEDED;
 711
 712         if (mp->m_flags & XFS_MOUNT_NORECOVERY) {
 713                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 714                 return 0;
 715         } else if (readonly) {
 716                 /* Allow unlinked processing to proceed */
 717                 mp->m_flags &= ~XFS_MOUNT_RDONLY;
 718         }
 719
 720         /*
 721          * During the second phase of log recovery, we need iget and
 722          * iput to behave like they do for an active filesystem.
 723          * xfs_fs_drop_inode needs to be able to prevent the deletion
 724          * of inodes before we're done replaying log items on those
 725          * inodes.  Turn it off immediately after recovery finishes
 726          * so that we don't leak the quota inodes if subsequent mount
 727          * activities fail.
 728          *
 729          * We let all inodes involved in redo item processing end up on
 730          * the LRU instead of being evicted immediately so that if we do
 731          * something to an unlinked inode, the irele won't cause
 732          * premature truncation and freeing of the inode, which results
 733          * in log recovery failure.  We have to evict the unreferenced
 734          * lru inodes after clearing SB_ACTIVE because we don't
 735          * otherwise clean up the lru if there's a subsequent failure in
 736          * xfs_mountfs, which leads to us leaking the inodes if nothing
 737          * else (e.g. quotacheck) references the inodes before the
 738          * mount failure occurs.
 739          */
 740         mp->m_super->s_flags |= SB_ACTIVE;
 741         error = xlog_recover_finish(mp->m_log);
 742         if (!error)
 743                 xfs_log_work_queue(mp);
 744         mp->m_super->s_flags &= ~SB_ACTIVE;
 745         evict_inodes(mp->m_super);
 746
 747         /*
 748          * Drain the buffer LRU after log recovery. This is required for v4
 749          * filesystems to avoid leaving around buffers with NULL verifier ops,
 750          * but we do it unconditionally to make sure we're always in a clean
 751          * cache state after mount.
 752          *
 753          * Don't push in the error case because the AIL may have pending intents
 754          * that aren't removed until recovery is cancelled.
 755          */
 756         if (!error && recovered) {
 757                 xfs_log_force(mp, XFS_LOG_SYNC);
 758                 xfs_ail_push_all_sync(mp->m_ail);
 759         }
 760         xfs_wait_buftarg(mp->m_ddev_targp);
 761
 762         if (readonly)
 763                 mp->m_flags |= XFS_MOUNT_RDONLY;
 764
 765         return error;
 766 }
 767
 768 /*
 769  * The mount has failed. Cancel the recovery if it hasn't completed and destroy
 770  * the log.
 771  */
 772 void
 773 xfs_log_mount_cancel(
 774         struct xfs_mount        *mp)
 775 {
 776         xlog_recover_cancel(mp->m_log);
 777         xfs_log_unmount(mp);
 778 }
 779
 780 /*
 781  * Final log writes as part of unmount.
 782  *
 783  * Mark the filesystem clean as unmount happens.  Note that during relocation
 784  * this routine needs to be executed as part of source-bag while the
 785  * deallocation must not be done until source-end.
 786  */
 787
 788 /* Actually write the unmount record to disk. */
 789 static void
 790 xfs_log_write_unmount_record(
 791         struct xfs_mount        *mp)
 792 {
 793         /* the data section must be 32 bit size aligned */
 794         struct xfs_unmount_log_format magic = {
 795                 .magic = XLOG_UNMOUNT_TYPE,
 796         };
 797         struct xfs_log_iovec reg = {
 798                 .i_addr = &magic,
 799                 .i_len = sizeof(magic),
 800                 .i_type = XLOG_REG_TYPE_UNMOUNT,
 801         };
 802         struct xfs_log_vec vec = {
 803                 .lv_niovecs = 1,
 804                 .lv_iovecp = &reg,
 805         };
 806         struct xlog             *log = mp->m_log;
 807         struct xlog_in_core     *iclog;
 808         struct xlog_ticket      *tic = NULL;
 809         xfs_lsn_t               lsn;
 810         uint                    flags = XLOG_UNMOUNT_TRANS;
 811         int                     error;
 812
 813         error = xfs_log_reserve(mp, 600, 1, &tic, XFS_LOG, 0);
 814         if (error)
 815                 goto out_err;
 816
 817         /*
 818          * If we think the summary counters are bad, clear the unmount header
 819          * flag in the unmount record so that the summary counters will be
 820          * recalculated during log recovery at next mount.  Refer to
 821          * xlog_check_unmount_rec for more details.
 822          */
 823         if (XFS_TEST_ERROR(xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS), mp,
 824                         XFS_ERRTAG_FORCE_SUMMARY_RECALC)) {
 825                 xfs_alert(mp, "%s: will fix summary counters at next mount",
 826                                 __func__);
 827                 flags &= ~XLOG_UNMOUNT_TRANS;
 828         }
 829
 830         /* remove inited flag, and account for space used */
 831         tic->t_flags = 0;
 832         tic->t_curr_res -= sizeof(magic);
 833         error = xlog_write(log, &vec, tic, &lsn, NULL, flags);
 834         /*
 835          * At this point, we're umounting anyway, so there's no point in
 836          * transitioning log state to IOERROR. Just continue...
 837          */
 838 out_err:
 839         if (error)
 840                 xfs_alert(mp, "%s: unmount record failed", __func__);
 841
 842         spin_lock(&log->l_icloglock);
 843         iclog = log->l_iclog;
 844         atomic_inc(&iclog->ic_refcnt);
 845         xlog_state_want_sync(log, iclog);
 846         spin_unlock(&log->l_icloglock);
 847         error = xlog_state_release_iclog(log, iclog);
 848
 849         spin_lock(&log->l_icloglock);
 850         switch (iclog->ic_state) {
 851         default:
 852                 if (!XLOG_FORCED_SHUTDOWN(log)) {
 853                         xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
 854                         break;
 855                 }
 856                 /* fall through */
 857         case XLOG_STATE_ACTIVE:
 858         case XLOG_STATE_DIRTY:
 859                 spin_unlock(&log->l_icloglock);
 860                 break;
 861         }
 862
 863         if (tic) {
 864                 trace_xfs_log_umount_write(log, tic);
 865                 xlog_ungrant_log_space(log, tic);
 866                 xfs_log_ticket_put(tic);
 867         }
 868 }
 869
 870 /*
 871  * Unmount record used to have a string "Unmount filesystem--" in the
 872  * data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
 873  * We just write the magic number now since that particular field isn't
 874  * currently architecture converted and "Unmount" is a bit foo.
 875  * As far as I know, there weren't any dependencies on the old behaviour.
 876  */
 877
 878 static int
 879 xfs_log_unmount_write(xfs_mount_t *mp)
 880 {
 881         struct xlog      *log = mp->m_log;
 882         xlog_in_core_t   *iclog;
 883 #ifdef DEBUG
 884         xlog_in_core_t   *first_iclog;
 885 #endif
 886         int              error;
 887
 888         /*
 889          * Don't write out unmount record on norecovery mounts or ro devices.
 890          * Or, if we are doing a forced umount (typically because of IO errors).
 891          */
 892         if (mp->m_flags & XFS_MOUNT_NORECOVERY ||
 893             xfs_readonly_buftarg(log->l_targ)) {
 894                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 895                 return 0;
 896         }
 897
 898         error = xfs_log_force(mp, XFS_LOG_SYNC);
 899         ASSERT(error || !(XLOG_FORCED_SHUTDOWN(log)));
 900
 901 #ifdef DEBUG
 902         first_iclog = iclog = log->l_iclog;
 903         do {
 904                 if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
 905                         ASSERT(iclog->ic_state & XLOG_STATE_ACTIVE);
 906                         ASSERT(iclog->ic_offset == 0);
 907                 }
 908                 iclog = iclog->ic_next;
 909         } while (iclog != first_iclog);
 910 #endif
 911         if (! (XLOG_FORCED_SHUTDOWN(log))) {
 912                 xfs_log_write_unmount_record(mp);
 913         } else {
 914                 /*
 915                  * We're already in forced_shutdown mode, couldn't
 916                  * even attempt to write out the unmount transaction.
 917                  *
 918                  * Go through the motions of sync'ing and releasing
 919                  * the iclog, even though no I/O will actually happen,
 920                  * we need to wait for other log I/Os that may already
 921                  * be in progress.  Do this as a separate section of
 922                  * code so we'll know if we ever get stuck here that
 923                  * we're in this odd situation of trying to unmount
 924                  * a file system that went into forced_shutdown as
 925                  * the result of an unmount..
 926                  */
 927                 spin_lock(&log->l_icloglock);
 928                 iclog = log->l_iclog;
 929                 atomic_inc(&iclog->ic_refcnt);
 930
 931                 xlog_state_want_sync(log, iclog);
 932                 spin_unlock(&log->l_icloglock);
 933                 error =  xlog_state_release_iclog(log, iclog);
 934
 935                 spin_lock(&log->l_icloglock);
 936
 937                 if ( ! (   iclog->ic_state == XLOG_STATE_ACTIVE
 938                         || iclog->ic_state == XLOG_STATE_DIRTY
 939                         || iclog->ic_state == XLOG_STATE_IOERROR) ) {
 940
 941                                 xlog_wait(&iclog->ic_force_wait,
 942                                                         &log->l_icloglock);
 943                 } else {
 944                         spin_unlock(&log->l_icloglock);
 945                 }
 946         }
 947
 948         return error;
 949 }       /* xfs_log_unmount_write */
 950
 951 /*
 952  * Empty the log for unmount/freeze.
 953  *
 954  * To do this, we first need to shut down the background log work so it is not
 955  * trying to cover the log as we clean up. We then need to unpin all objects in
 956  * the log so we can then flush them out. Once they have completed their IO and
 957  * run the callbacks removing themselves from the AIL, we can write the unmount
 958  * record.
 959  */
 960 void
 961 xfs_log_quiesce(
 962         struct xfs_mount        *mp)
 963 {
 964         cancel_delayed_work_sync(&mp->m_log->l_work);
 965         xfs_log_force(mp, XFS_LOG_SYNC);
 966
 967         /*
 968          * The superblock buffer is uncached and while xfs_ail_push_all_sync()
 969          * will push it, xfs_wait_buftarg() will not wait for it. Further,
 970          * xfs_buf_iowait() cannot be used because it was pushed with the
 971          * XBF_ASYNC flag set, so we need to use a lock/unlock pair to wait for
 972          * the IO to complete.
 973          */
 974         xfs_ail_push_all_sync(mp->m_ail);
 975         xfs_wait_buftarg(mp->m_ddev_targp);
 976         xfs_buf_lock(mp->m_sb_bp);
 977         xfs_buf_unlock(mp->m_sb_bp);
 978
 979         xfs_log_unmount_write(mp);
 980 }
 981
 982 /*
 983  * Shut down and release the AIL and Log.
 984  *
 985  * During unmount, we need to ensure we flush all the dirty metadata objects
 986  * from the AIL so that the log is empty before we write the unmount record to
 987  * the log. Once this is done, we can tear down the AIL and the log.
 988  */
 989 void
 990 xfs_log_unmount(
 991         struct xfs_mount        *mp)
 992 {
 993         xfs_log_quiesce(mp);
 994
 995         xfs_trans_ail_destroy(mp);
 996
 997         xfs_sysfs_del(&mp->m_log->l_kobj);
 998
 999         xlog_dealloc_log(mp->m_log);
1000 }
1001
1002 void
1003 xfs_log_item_init(
1004         struct xfs_mount        *mp,
1005         struct xfs_log_item     *item,
1006         int                     type,
1007         const struct xfs_item_ops *ops)
1008 {
1009         item->li_mountp = mp;
1010         item->li_ailp = mp->m_ail;
1011         item->li_type = type;
1012         item->li_ops = ops;
1013         item->li_lv = NULL;
1014
1015         INIT_LIST_HEAD(&item->li_ail);
1016         INIT_LIST_HEAD(&item->li_cil);
1017         INIT_LIST_HEAD(&item->li_bio_list);
1018         INIT_LIST_HEAD(&item->li_trans);
1019 }
1020
1021 /*
1022  * Wake up processes waiting for log space after we have moved the log tail.
1023  */
1024 void
1025 xfs_log_space_wake(
1026         struct xfs_mount        *mp)
1027 {
1028         struct xlog             *log = mp->m_log;
1029         int                     free_bytes;
1030
1031         if (XLOG_FORCED_SHUTDOWN(log))
1032                 return;
1033
1034         if (!list_empty_careful(&log->l_write_head.waiters)) {
1035                 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
1036
1037                 spin_lock(&log->l_write_head.lock);
1038                 free_bytes = xlog_space_left(log, &log->l_write_head.grant);
1039                 xlog_grant_head_wake(log, &log->l_write_head, &free_bytes);
1040                 spin_unlock(&log->l_write_head.lock);
1041         }
1042
1043         if (!list_empty_careful(&log->l_reserve_head.waiters)) {
1044                 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
1045
1046                 spin_lock(&log->l_reserve_head.lock);
1047                 free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1048                 xlog_grant_head_wake(log, &log->l_reserve_head, &free_bytes);
1049                 spin_unlock(&log->l_reserve_head.lock);
1050         }
1051 }
1052
1053 /*
1054  * Determine if we have a transaction that has gone to disk that needs to be
1055  * covered. To begin the transition to the idle state firstly the log needs to
1056  * be idle. That means the CIL, the AIL and the iclogs needs to be empty before
1057  * we start attempting to cover the log.
1058  *
1059  * Only if we are then in a state where covering is needed, the caller is
1060  * informed that dummy transactions are required to move the log into the idle
1061  * state.
1062  *
1063  * If there are any items in the AIl or CIL, then we do not want to attempt to
1064  * cover the log as we may be in a situation where there isn't log space
1065  * available to run a dummy transaction and this can lead to deadlocks when the
1066  * tail of the log is pinned by an item that is modified in the CIL.  Hence
1067  * there's no point in running a dummy transaction at this point because we
1068  * can't start trying to idle the log until both the CIL and AIL are empty.
1069  */
1070 static int
1071 xfs_log_need_covered(xfs_mount_t *mp)
1072 {
1073         struct xlog     *log = mp->m_log;
1074         int             needed = 0;
1075
1076         if (!xfs_fs_writable(mp, SB_FREEZE_WRITE))
1077                 return 0;
1078
1079         if (!xlog_cil_empty(log))
1080                 return 0;
1081
1082         spin_lock(&log->l_icloglock);
1083         switch (log->l_covered_state) {
1084         case XLOG_STATE_COVER_DONE:
1085         case XLOG_STATE_COVER_DONE2:
1086         case XLOG_STATE_COVER_IDLE:
1087                 break;
1088         case XLOG_STATE_COVER_NEED:
1089         case XLOG_STATE_COVER_NEED2:
1090                 if (xfs_ail_min_lsn(log->l_ailp))
1091                         break;
1092                 if (!xlog_iclogs_empty(log))
1093                         break;
1094
1095                 needed = 1;
1096                 if (log->l_covered_state == XLOG_STATE_COVER_NEED)
1097                         log->l_covered_state = XLOG_STATE_COVER_DONE;
1098                 else
1099                         log->l_covered_state = XLOG_STATE_COVER_DONE2;
1100                 break;
1101         default:
1102                 needed = 1;
1103                 break;
1104         }
1105         spin_unlock(&log->l_icloglock);
1106         return needed;
1107 }
1108
1109 /*
1110  * We may be holding the log iclog lock upon entering this routine.
1111  */
1112 xfs_lsn_t
1113 xlog_assign_tail_lsn_locked(
1114         struct xfs_mount        *mp)
1115 {
1116         struct xlog             *log = mp->m_log;
1117         struct xfs_log_item     *lip;
1118         xfs_lsn_t               tail_lsn;
1119
1120         assert_spin_locked(&mp->m_ail->ail_lock);
1121
1122         /*
1123          * To make sure we always have a valid LSN for the log tail we keep
1124          * track of the last LSN which was committed in log->l_last_sync_lsn,
1125          * and use that when the AIL was empty.
1126          */
1127         lip = xfs_ail_min(mp->m_ail);
1128         if (lip)
1129                 tail_lsn = lip->li_lsn;
1130         else
1131                 tail_lsn = atomic64_read(&log->l_last_sync_lsn);
1132         trace_xfs_log_assign_tail_lsn(log, tail_lsn);
1133         atomic64_set(&log->l_tail_lsn, tail_lsn);
1134         return tail_lsn;
1135 }
1136
1137 xfs_lsn_t
1138 xlog_assign_tail_lsn(
1139         struct xfs_mount        *mp)
1140 {
1141         xfs_lsn_t               tail_lsn;
1142
1143         spin_lock(&mp->m_ail->ail_lock);
1144         tail_lsn = xlog_assign_tail_lsn_locked(mp);
1145         spin_unlock(&mp->m_ail->ail_lock);
1146
1147         return tail_lsn;
1148 }
1149
1150 /*
1151  * Return the space in the log between the tail and the head.  The head
1152  * is passed in the cycle/bytes formal parms.  In the special case where
1153  * the reserve head has wrapped passed the tail, this calculation is no
1154  * longer valid.  In this case, just return 0 which means there is no space
1155  * in the log.  This works for all places where this function is called
1156  * with the reserve head.  Of course, if the write head were to ever
1157  * wrap the tail, we should blow up.  Rather than catch this case here,
1158  * we depend on other ASSERTions in other parts of the code.   XXXmiken
1159  *
1160  * This code also handles the case where the reservation head is behind
1161  * the tail.  The details of this case are described below, but the end
1162  * result is that we return the size of the log as the amount of space left.
1163  */
1164 STATIC int
1165 xlog_space_left(
1166         struct xlog     *log,
1167         atomic64_t      *head)
1168 {
1169         int             free_bytes;
1170         int             tail_bytes;
1171         int             tail_cycle;
1172         int             head_cycle;
1173         int             head_bytes;
1174
1175         xlog_crack_grant_head(head, &head_cycle, &head_bytes);
1176         xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_bytes);
1177         tail_bytes = BBTOB(tail_bytes);
1178         if (tail_cycle == head_cycle && head_bytes >= tail_bytes)
1179                 free_bytes = log->l_logsize - (head_bytes - tail_bytes);
1180         else if (tail_cycle + 1 < head_cycle)
1181                 return 0;
1182         else if (tail_cycle < head_cycle) {
1183                 ASSERT(tail_cycle == (head_cycle - 1));
1184                 free_bytes = tail_bytes - head_bytes;
1185         } else {
1186                 /*
1187                  * The reservation head is behind the tail.
1188                  * In this case we just want to return the size of the
1189                  * log as the amount of space left.
1190                  */
1191                 xfs_alert(log->l_mp, "xlog_space_left: head behind tail");
1192                 xfs_alert(log->l_mp,
1193                           "  tail_cycle = %d, tail_bytes = %d",
1194                           tail_cycle, tail_bytes);
1195                 xfs_alert(log->l_mp,
1196                           "  GH   cycle = %d, GH   bytes = %d",
1197                           head_cycle, head_bytes);
1198                 ASSERT(0);
1199                 free_bytes = log->l_logsize;
1200         }
1201         return free_bytes;
1202 }
1203
1204
1205 static void
1206 xlog_ioend_work(
1207         struct work_struct      *work)
1208 {
1209         struct xlog_in_core     *iclog =
1210                 container_of(work, struct xlog_in_core, ic_end_io_work);
1211         struct xlog             *log = iclog->ic_log;
1212         bool                    aborted = false;
1213         int                     error;
1214
1215         error = blk_status_to_errno(iclog->ic_bio.bi_status);
1216 #ifdef DEBUG
1217         /* treat writes with injected CRC errors as failed */
1218         if (iclog->ic_fail_crc)
1219                 error = -EIO;
1220 #endif
1221
1222         /*
1223          * Race to shutdown the filesystem if we see an error.
1224          */
1225         if (XFS_TEST_ERROR(error, log->l_mp, XFS_ERRTAG_IODONE_IOERR)) {
1226                 xfs_alert(log->l_mp, "log I/O error %d", error);
1227                 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
1228                 /*
1229                  * This flag will be propagated to the trans-committed
1230                  * callback routines to let them know that the log-commit
1231                  * didn't succeed.
1232                  */
1233                 aborted = true;
1234         } else if (iclog->ic_state & XLOG_STATE_IOERROR) {
1235                 aborted = true;
1236         }
1237
1238         xlog_state_done_syncing(iclog, aborted);
1239         bio_uninit(&iclog->ic_bio);
1240
1241         /*
1242          * Drop the lock to signal that we are done. Nothing references the
1243          * iclog after this, so an unmount waiting on this lock can now tear it
1244          * down safely. As such, it is unsafe to reference the iclog after the
1245          * unlock as we could race with it being freed.
1246          */
1247         up(&iclog->ic_sema);
1248 }
1249
1250 /*
1251  * Return size of each in-core log record buffer.
1252  *
1253  * All machines get 8 x 32kB buffers by default, unless tuned otherwise.
1254  *
1255  * If the filesystem blocksize is too large, we may need to choose a
1256  * larger size since the directory code currently logs entire blocks.
1257  */
1258 STATIC void
1259 xlog_get_iclog_buffer_size(
1260         struct xfs_mount        *mp,
1261         struct xlog             *log)
1262 {
1263         if (mp->m_logbufs <= 0)
1264                 mp->m_logbufs = XLOG_MAX_ICLOGS;
1265         if (mp->m_logbsize <= 0)
1266                 mp->m_logbsize = XLOG_BIG_RECORD_BSIZE;
1267
1268         log->l_iclog_bufs = mp->m_logbufs;
1269         log->l_iclog_size = mp->m_logbsize;
1270
1271         /*
1272          * # headers = size / 32k - one header holds cycles from 32k of data.
1273          */
1274         log->l_iclog_heads =
1275                 DIV_ROUND_UP(mp->m_logbsize, XLOG_HEADER_CYCLE_SIZE);
1276         log->l_iclog_hsize = log->l_iclog_heads << BBSHIFT;
1277 }
1278
1279 void
1280 xfs_log_work_queue(
1281         struct xfs_mount        *mp)
1282 {
1283         queue_delayed_work(mp->m_sync_workqueue, &mp->m_log->l_work,
1284                                 msecs_to_jiffies(xfs_syncd_centisecs * 10));
1285 }
1286
1287 /*
1288  * Every sync period we need to unpin all items in the AIL and push them to
1289  * disk. If there is nothing dirty, then we might need to cover the log to
1290  * indicate that the filesystem is idle.
1291  */
1292 static void
1293 xfs_log_worker(
1294         struct work_struct      *work)
1295 {
1296         struct xlog             *log = container_of(to_delayed_work(work),
1297                                                 struct xlog, l_work);
1298         struct xfs_mount        *mp = log->l_mp;
1299
1300         /* dgc: errors ignored - not fatal and nowhere to report them */
1301         if (xfs_log_need_covered(mp)) {
1302                 /*
1303                  * Dump a transaction into the log that contains no real change.
1304                  * This is needed to stamp the current tail LSN into the log
1305                  * during the covering operation.
1306                  *
1307                  * We cannot use an inode here for this - that will push dirty
1308                  * state back up into the VFS and then periodic inode flushing
1309                  * will prevent log covering from making progress. Hence we
1310                  * synchronously log the superblock instead to ensure the
1311                  * superblock is immediately unpinned and can be written back.
1312                  */
1313                 xfs_sync_sb(mp, true);
1314         } else
1315                 xfs_log_force(mp, 0);
1316
1317         /* start pushing all the metadata that is currently dirty */
1318         xfs_ail_push_all(mp->m_ail);
1319
1320         /* queue us up again */
1321         xfs_log_work_queue(mp);
1322 }
1323
1324 /*
1325  * This routine initializes some of the log structure for a given mount point.
1326  * Its primary purpose is to fill in enough, so recovery can occur.  However,
1327  * some other stuff may be filled in too.
1328  */
1329 STATIC struct xlog *
1330 xlog_alloc_log(
1331         struct xfs_mount        *mp,
1332         struct xfs_buftarg      *log_target,
1333         xfs_daddr_t             blk_offset,
1334         int                     num_bblks)
1335 {
1336         struct xlog             *log;
1337         xlog_rec_header_t       *head;
1338         xlog_in_core_t          **iclogp;
1339         xlog_in_core_t          *iclog, *prev_iclog=NULL;
1340         int                     i;
1341         int                     error = -ENOMEM;
1342         uint                    log2_size = 0;
1343
1344         log = kmem_zalloc(sizeof(struct xlog), KM_MAYFAIL);
1345         if (!log) {
1346                 xfs_warn(mp, "Log allocation failed: No memory!");
1347                 goto out;
1348         }
1349
1350         log->l_mp          = mp;
1351         log->l_targ        = log_target;
1352         log->l_logsize     = BBTOB(num_bblks);
1353         log->l_logBBstart  = blk_offset;
1354         log->l_logBBsize   = num_bblks;
1355         log->l_covered_state = XLOG_STATE_COVER_IDLE;
1356         log->l_flags       |= XLOG_ACTIVE_RECOVERY;
1357         INIT_DELAYED_WORK(&log->l_work, xfs_log_worker);
1358
1359         log->l_prev_block  = -1;
1360         /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
1361         xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0);
1362         xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
1363         log->l_curr_cycle  = 1;     /* 0 is bad since this is initial value */
1364
1365         xlog_grant_head_init(&log->l_reserve_head);
1366         xlog_grant_head_init(&log->l_write_head);
1367
1368         error = -EFSCORRUPTED;
1369         if (xfs_sb_version_hassector(&mp->m_sb)) {
1370                 log2_size = mp->m_sb.sb_logsectlog;
1371                 if (log2_size < BBSHIFT) {
1372                         xfs_warn(mp, "Log sector size too small (0x%x < 0x%x)",
1373                                 log2_size, BBSHIFT);
1374                         goto out_free_log;
1375                 }
1376
1377                 log2_size -= BBSHIFT;
1378                 if (log2_size > mp->m_sectbb_log) {
1379                         xfs_warn(mp, "Log sector size too large (0x%x > 0x%x)",
1380                                 log2_size, mp->m_sectbb_log);
1381                         goto out_free_log;
1382                 }
1383
1384                 /* for larger sector sizes, must have v2 or external log */
1385                 if (log2_size && log->l_logBBstart > 0 &&
1386                             !xfs_sb_version_haslogv2(&mp->m_sb)) {
1387                         xfs_warn(mp,
1388                 "log sector size (0x%x) invalid for configuration.",
1389                                 log2_size);
1390                         goto out_free_log;
1391                 }
1392         }
1393         log->l_sectBBsize = 1 << log2_size;
1394
1395         xlog_get_iclog_buffer_size(mp, log);
1396
1397         spin_lock_init(&log->l_icloglock);
1398         init_waitqueue_head(&log->l_flush_wait);
1399
1400         iclogp = &log->l_iclog;
1401         /*
1402          * The amount of memory to allocate for the iclog structure is
1403          * rather funky due to the way the structure is defined.  It is
1404          * done this way so that we can use different sizes for machines
1405          * with different amounts of memory.  See the definition of
1406          * xlog_in_core_t in xfs_log_priv.h for details.
1407          */
1408         ASSERT(log->l_iclog_size >= 4096);
1409         for (i = 0; i < log->l_iclog_bufs; i++) {
1410                 size_t bvec_size = howmany(log->l_iclog_size, PAGE_SIZE) *
1411                                 sizeof(struct bio_vec);
1412
1413                 iclog = kmem_zalloc(sizeof(*iclog) + bvec_size, KM_MAYFAIL);
1414                 if (!iclog)
1415                         goto out_free_iclog;
1416
1417                 *iclogp = iclog;
1418                 iclog->ic_prev = prev_iclog;
1419                 prev_iclog = iclog;
1420
1421                 iclog->ic_data = kmem_alloc_large(log->l_iclog_size,
1422                                 KM_MAYFAIL);
1423                 if (!iclog->ic_data)
1424                         goto out_free_iclog;
1425 #ifdef DEBUG
1426                 log->l_iclog_bak[i] = &iclog->ic_header;
1427 #endif
1428                 head = &iclog->ic_header;
1429                 memset(head, 0, sizeof(xlog_rec_header_t));
1430                 head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1431                 head->h_version = cpu_to_be32(
1432                         xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? 2 : 1);
1433                 head->h_size = cpu_to_be32(log->l_iclog_size);
1434                 /* new fields */
1435                 head->h_fmt = cpu_to_be32(XLOG_FMT);
1436                 memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));
1437
1438                 iclog->ic_size = log->l_iclog_size - log->l_iclog_hsize;
1439                 iclog->ic_state = XLOG_STATE_ACTIVE;
1440                 iclog->ic_log = log;
1441                 atomic_set(&iclog->ic_refcnt, 0);
1442                 spin_lock_init(&iclog->ic_callback_lock);
1443                 INIT_LIST_HEAD(&iclog->ic_callbacks);
1444                 iclog->ic_datap = (char *)iclog->ic_data + log->l_iclog_hsize;
1445
1446                 init_waitqueue_head(&iclog->ic_force_wait);
1447                 init_waitqueue_head(&iclog->ic_write_wait);
1448                 INIT_WORK(&iclog->ic_end_io_work, xlog_ioend_work);
1449                 sema_init(&iclog->ic_sema, 1);
1450
1451                 iclogp = &iclog->ic_next;
1452         }
1453         *iclogp = log->l_iclog;                 /* complete ring */
1454         log->l_iclog->ic_prev = prev_iclog;     /* re-write 1st prev ptr */
1455
1456         log->l_ioend_workqueue = alloc_workqueue("xfs-log/%s",
1457                         WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_HIGHPRI, 0,
1458                         mp->m_fsname);
1459         if (!log->l_ioend_workqueue)
1460                 goto out_free_iclog;
1461
1462         error = xlog_cil_init(log);
1463         if (error)
1464                 goto out_destroy_workqueue;
1465         return log;
1466
1467 out_destroy_workqueue:
1468         destroy_workqueue(log->l_ioend_workqueue);
1469 out_free_iclog:
1470         for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
1471                 prev_iclog = iclog->ic_next;
1472                 kmem_free(iclog->ic_data);
1473                 kmem_free(iclog);
1474         }
1475 out_free_log:
1476         kmem_free(log);
1477 out:
1478         return ERR_PTR(error);
1479 }       /* xlog_alloc_log */
1480
1481
1482 /*
1483  * Write out the commit record of a transaction associated with the given
1484  * ticket.  Return the lsn of the commit record.
1485  */
1486 STATIC int
1487 xlog_commit_record(
1488         struct xlog             *log,
1489         struct xlog_ticket      *ticket,
1490         struct xlog_in_core     **iclog,
1491         xfs_lsn_t               *commitlsnp)
1492 {
1493         struct xfs_mount *mp = log->l_mp;
1494         int     error;
1495         struct xfs_log_iovec reg = {
1496                 .i_addr = NULL,
1497                 .i_len = 0,
1498                 .i_type = XLOG_REG_TYPE_COMMIT,
1499         };
1500         struct xfs_log_vec vec = {
1501                 .lv_niovecs = 1,
1502                 .lv_iovecp = &reg,
1503         };
1504
1505         ASSERT_ALWAYS(iclog);
1506         error = xlog_write(log, &vec, ticket, commitlsnp, iclog,
1507                                         XLOG_COMMIT_TRANS);
1508         if (error)
1509                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
1510         return error;
1511 }
1512
1513 /*
1514  * Push on the buffer cache code if we ever use more than 75% of the on-disk
1515  * log space.  This code pushes on the lsn which would supposedly free up
1516  * the 25% which we want to leave free.  We may need to adopt a policy which
1517  * pushes on an lsn which is further along in the log once we reach the high
1518  * water mark.  In this manner, we would be creating a low water mark.
1519  */
1520 STATIC void
1521 xlog_grant_push_ail(
1522         struct xlog     *log,
1523         int             need_bytes)
1524 {
1525         xfs_lsn_t       threshold_lsn = 0;
1526         xfs_lsn_t       last_sync_lsn;
1527         int             free_blocks;
1528         int             free_bytes;
1529         int             threshold_block;
1530         int             threshold_cycle;
1531         int             free_threshold;
1532
1533         ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
1534
1535         free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1536         free_blocks = BTOBBT(free_bytes);
1537
1538         /*
1539          * Set the threshold for the minimum number of free blocks in the
1540          * log to the maximum of what the caller needs, one quarter of the
1541          * log, and 256 blocks.
1542          */
1543         free_threshold = BTOBB(need_bytes);
1544         free_threshold = max(free_threshold, (log->l_logBBsize >> 2));
1545         free_threshold = max(free_threshold, 256);
1546         if (free_blocks >= free_threshold)
1547                 return;
1548
1549         xlog_crack_atomic_lsn(&log->l_tail_lsn, &threshold_cycle,
1550                                                 &threshold_block);
1551         threshold_block += free_threshold;
1552         if (threshold_block >= log->l_logBBsize) {
1553                 threshold_block -= log->l_logBBsize;
1554                 threshold_cycle += 1;
1555         }
1556         threshold_lsn = xlog_assign_lsn(threshold_cycle,
1557                                         threshold_block);
1558         /*
1559          * Don't pass in an lsn greater than the lsn of the last
1560          * log record known to be on disk. Use a snapshot of the last sync lsn
1561          * so that it doesn't change between the compare and the set.
1562          */
1563         last_sync_lsn = atomic64_read(&log->l_last_sync_lsn);
1564         if (XFS_LSN_CMP(threshold_lsn, last_sync_lsn) > 0)
1565                 threshold_lsn = last_sync_lsn;
1566
1567         /*
1568          * Get the transaction layer to kick the dirty buffers out to
1569          * disk asynchronously. No point in trying to do this if
1570          * the filesystem is shutting down.
1571          */
1572         if (!XLOG_FORCED_SHUTDOWN(log))
1573                 xfs_ail_push(log->l_ailp, threshold_lsn);
1574 }
1575
1576 /*
1577  * Stamp cycle number in every block
1578  */
1579 STATIC void
1580 xlog_pack_data(
1581         struct xlog             *log,
1582         struct xlog_in_core     *iclog,
1583         int                     roundoff)
1584 {
1585         int                     i, j, k;
1586         int                     size = iclog->ic_offset + roundoff;
1587         __be32                  cycle_lsn;
1588         char                    *dp;
1589
1590         cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn);
1591
1592         dp = iclog->ic_datap;
1593         for (i = 0; i < BTOBB(size); i++) {
1594                 if (i >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE))
1595                         break;
1596                 iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp;
1597                 *(__be32 *)dp = cycle_lsn;
1598                 dp += BBSIZE;
1599         }
1600
1601         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1602                 xlog_in_core_2_t *xhdr = iclog->ic_data;
1603
1604                 for ( ; i < BTOBB(size); i++) {
1605                         j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1606                         k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1607                         xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp;
1608                         *(__be32 *)dp = cycle_lsn;
1609                         dp += BBSIZE;
1610                 }
1611
1612                 for (i = 1; i < log->l_iclog_heads; i++)
1613                         xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
1614         }
1615 }
1616
1617 /*
1618  * Calculate the checksum for a log buffer.
1619  *
1620  * This is a little more complicated than it should be because the various
1621  * headers and the actual data are non-contiguous.
1622  */
1623 __le32
1624 xlog_cksum(
1625         struct xlog             *log,
1626         struct xlog_rec_header  *rhead,
1627         char                    *dp,
1628         int                     size)
1629 {
1630         uint32_t                crc;
1631
1632         /* first generate the crc for the record header ... */
1633         crc = xfs_start_cksum_update((char *)rhead,
1634                               sizeof(struct xlog_rec_header),
1635                               offsetof(struct xlog_rec_header, h_crc));
1636
1637         /* ... then for additional cycle data for v2 logs ... */
1638         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1639                 union xlog_in_core2 *xhdr = (union xlog_in_core2 *)rhead;
1640                 int             i;
1641                 int             xheads;
1642
1643                 xheads = size / XLOG_HEADER_CYCLE_SIZE;
1644                 if (size % XLOG_HEADER_CYCLE_SIZE)
1645                         xheads++;
1646
1647                 for (i = 1; i < xheads; i++) {
1648                         crc = crc32c(crc, &xhdr[i].hic_xheader,
1649                                      sizeof(struct xlog_rec_ext_header));
1650                 }
1651         }
1652
1653         /* ... and finally for the payload */
1654         crc = crc32c(crc, dp, size);
1655
1656         return xfs_end_cksum(crc);
1657 }
1658
1659 static void
1660 xlog_bio_end_io(
1661         struct bio              *bio)
1662 {
1663         struct xlog_in_core     *iclog = bio->bi_private;
1664
1665         queue_work(iclog->ic_log->l_ioend_workqueue,
1666                    &iclog->ic_end_io_work);
1667 }
1668
1669 static void
1670 xlog_map_iclog_data(
1671         struct bio              *bio,
1672         void                    *data,
1673         size_t                  count)
1674 {
1675         do {
1676                 struct page     *page = kmem_to_page(data);
1677                 unsigned int    off = offset_in_page(data);
1678                 size_t          len = min_t(size_t, count, PAGE_SIZE - off);
1679
1680                 WARN_ON_ONCE(bio_add_page(bio, page, len, off) != len);
1681
1682                 data += len;
1683                 count -= len;
1684         } while (count);
1685 }
1686
1687 STATIC void
1688 xlog_write_iclog(
1689         struct xlog             *log,
1690         struct xlog_in_core     *iclog,
1691         uint64_t                bno,
1692         unsigned int            count,
1693         bool                    need_flush)
1694 {
1695         ASSERT(bno < log->l_logBBsize);
1696
1697         /*
1698          * We lock the iclogbufs here so that we can serialise against I/O
1699          * completion during unmount.  We might be processing a shutdown
1700          * triggered during unmount, and that can occur asynchronously to the
1701          * unmount thread, and hence we need to ensure that completes before
1702          * tearing down the iclogbufs.  Hence we need to hold the buffer lock
1703          * across the log IO to archieve that.
1704          */
1705         down(&iclog->ic_sema);
1706         if (unlikely(iclog->ic_state & XLOG_STATE_IOERROR)) {
1707                 /*
1708                  * It would seem logical to return EIO here, but we rely on
1709                  * the log state machine to propagate I/O errors instead of
1710                  * doing it here.  We kick of the state machine and unlock
1711                  * the buffer manually, the code needs to be kept in sync
1712                  * with the I/O completion path.
1713                  */
1714                 xlog_state_done_syncing(iclog, XFS_LI_ABORTED);
1715                 up(&iclog->ic_sema);
1716                 return;
1717         }
1718
1719         iclog->ic_io_size = count;
1720
1721         bio_init(&iclog->ic_bio, iclog->ic_bvec, howmany(count, PAGE_SIZE));
1722         bio_set_dev(&iclog->ic_bio, log->l_targ->bt_bdev);
1723         iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart + bno;
1724         iclog->ic_bio.bi_end_io = xlog_bio_end_io;
1725         iclog->ic_bio.bi_private = iclog;
1726         iclog->ic_bio.bi_opf = REQ_OP_WRITE | REQ_META | REQ_SYNC | REQ_FUA;
1727         if (need_flush)
1728                 iclog->ic_bio.bi_opf |= REQ_PREFLUSH;
1729
1730         xlog_map_iclog_data(&iclog->ic_bio, iclog->ic_data, iclog->ic_io_size);
1731         if (is_vmalloc_addr(iclog->ic_data))
1732                 flush_kernel_vmap_range(iclog->ic_data, iclog->ic_io_size);
1733
1734         /*
1735          * If this log buffer would straddle the end of the log we will have
1736          * to split it up into two bios, so that we can continue at the start.
1737          */
1738         if (bno + BTOBB(count) > log->l_logBBsize) {
1739                 struct bio *split;
1740
1741                 split = bio_split(&iclog->ic_bio, log->l_logBBsize - bno,
1742                                   GFP_NOIO, &fs_bio_set);
1743                 bio_chain(split, &iclog->ic_bio);
1744                 submit_bio(split);
1745
1746                 /* restart at logical offset zero for the remainder */
1747                 iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart;
1748         }
1749
1750         submit_bio(&iclog->ic_bio);
1751 }
1752
1753 /*
1754  * We need to bump cycle number for the part of the iclog that is
1755  * written to the start of the log. Watch out for the header magic
1756  * number case, though.
1757  */
1758 static void
1759 xlog_split_iclog(
1760         struct xlog             *log,
1761         void                    *data,
1762         uint64_t                bno,
1763         unsigned int            count)
1764 {
1765         unsigned int            split_offset = BBTOB(log->l_logBBsize - bno);
1766         unsigned int            i;
1767
1768         for (i = split_offset; i < count; i += BBSIZE) {
1769                 uint32_t cycle = get_unaligned_be32(data + i);
1770
1771                 if (++cycle == XLOG_HEADER_MAGIC_NUM)
1772                         cycle++;
1773                 put_unaligned_be32(cycle, data + i);
1774         }
1775 }
1776
1777 static int
1778 xlog_calc_iclog_size(
1779         struct xlog             *log,
1780         struct xlog_in_core     *iclog,
1781         uint32_t                *roundoff)
1782 {
1783         uint32_t                count_init, count;
1784         bool                    use_lsunit;
1785
1786         use_lsunit = xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
1787                         log->l_mp->m_sb.sb_logsunit > 1;
1788
1789         /* Add for LR header */
1790         count_init = log->l_iclog_hsize + iclog->ic_offset;
1791
1792         /* Round out the log write size */
1793         if (use_lsunit) {
1794                 /* we have a v2 stripe unit to use */
1795                 count = XLOG_LSUNITTOB(log, XLOG_BTOLSUNIT(log, count_init));
1796         } else {
1797                 count = BBTOB(BTOBB(count_init));
1798         }
1799
1800         ASSERT(count >= count_init);
1801         *roundoff = count - count_init;
1802
1803         if (use_lsunit)
1804                 ASSERT(*roundoff < log->l_mp->m_sb.sb_logsunit);
1805         else
1806                 ASSERT(*roundoff < BBTOB(1));
1807         return count;
1808 }
1809
1810 /*
1811  * Flush out the in-core log (iclog) to the on-disk log in an asynchronous
1812  * fashion.  Previously, we should have moved the current iclog
1813  * ptr in the log to point to the next available iclog.  This allows further
1814  * write to continue while this code syncs out an iclog ready to go.
1815  * Before an in-core log can be written out, the data section must be scanned
1816  * to save away the 1st word of each BBSIZE block into the header.  We replace
1817  * it with the current cycle count.  Each BBSIZE block is tagged with the
1818  * cycle count because there in an implicit assumption that drives will
1819  * guarantee that entire 512 byte blocks get written at once.  In other words,
1820  * we can't have part of a 512 byte block written and part not written.  By
1821  * tagging each block, we will know which blocks are valid when recovering
1822  * after an unclean shutdown.
1823  *
1824  * This routine is single threaded on the iclog.  No other thread can be in
1825  * this routine with the same iclog.  Changing contents of iclog can there-
1826  * fore be done without grabbing the state machine lock.  Updating the global
1827  * log will require grabbing the lock though.
1828  *
1829  * The entire log manager uses a logical block numbering scheme.  Only
1830  * xlog_write_iclog knows about the fact that the log may not start with
1831  * block zero on a given device.
1832  */
1833 STATIC void
1834 xlog_sync(
1835         struct xlog             *log,
1836         struct xlog_in_core     *iclog)
1837 {
1838         unsigned int            count;          /* byte count of bwrite */
1839         unsigned int            roundoff;       /* roundoff to BB or stripe */
1840         uint64_t                bno;
1841         unsigned int            size;
1842         bool                    need_flush = true, split = false;
1843
1844         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
1845
1846         count = xlog_calc_iclog_size(log, iclog, &roundoff);
1847
1848         /* move grant heads by roundoff in sync */
1849         xlog_grant_add_space(log, &log->l_reserve_head.grant, roundoff);
1850         xlog_grant_add_space(log, &log->l_write_head.grant, roundoff);
1851
1852         /* put cycle number in every block */
1853         xlog_pack_data(log, iclog, roundoff);
1854
1855         /* real byte length */
1856         size = iclog->ic_offset;
1857         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb))
1858                 size += roundoff;
1859         iclog->ic_header.h_len = cpu_to_be32(size);
1860
1861         XFS_STATS_INC(log->l_mp, xs_log_writes);
1862         XFS_STATS_ADD(log->l_mp, xs_log_blocks, BTOBB(count));
1863
1864         bno = BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn));
1865
1866         /* Do we need to split this write into 2 parts? */
1867         if (bno + BTOBB(count) > log->l_logBBsize) {
1868                 xlog_split_iclog(log, &iclog->ic_header, bno, count);
1869                 split = true;
1870         }
1871
1872         /* calculcate the checksum */
1873         iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header,
1874                                             iclog->ic_datap, size);
1875         /*
1876          * Intentionally corrupt the log record CRC based on the error injection
1877          * frequency, if defined. This facilitates testing log recovery in the
1878          * event of torn writes. Hence, set the IOABORT state to abort the log
1879          * write on I/O completion and shutdown the fs. The subsequent mount
1880          * detects the bad CRC and attempts to recover.
1881          */
1882 #ifdef DEBUG
1883         if (XFS_TEST_ERROR(false, log->l_mp, XFS_ERRTAG_LOG_BAD_CRC)) {
1884                 iclog->ic_header.h_crc &= cpu_to_le32(0xAAAAAAAA);
1885                 iclog->ic_fail_crc = true;
1886                 xfs_warn(log->l_mp,
1887         "Intentionally corrupted log record at LSN 0x%llx. Shutdown imminent.",
1888                          be64_to_cpu(iclog->ic_header.h_lsn));
1889         }
1890 #endif
1891
1892         /*
1893          * Flush the data device before flushing the log to make sure all meta
1894          * data written back from the AIL actually made it to disk before
1895          * stamping the new log tail LSN into the log buffer.  For an external
1896          * log we need to issue the flush explicitly, and unfortunately
1897          * synchronously here; for an internal log we can simply use the block
1898          * layer state machine for preflushes.
1899          */
1900         if (log->l_targ != log->l_mp->m_ddev_targp || split) {
1901                 xfs_blkdev_issue_flush(log->l_mp->m_ddev_targp);
1902                 need_flush = false;
1903         }
1904
1905         xlog_verify_iclog(log, iclog, count);
1906         xlog_write_iclog(log, iclog, bno, count, need_flush);
1907 }
1908
1909 /*
1910  * Deallocate a log structure
1911  */
1912 STATIC void
1913 xlog_dealloc_log(
1914         struct xlog     *log)
1915 {
1916         xlog_in_core_t  *iclog, *next_iclog;
1917         int             i;
1918
1919         xlog_cil_destroy(log);
1920
1921         /*
1922          * Cycle all the iclogbuf locks to make sure all log IO completion
1923          * is done before we tear down these buffers.
1924          */
1925         iclog = log->l_iclog;
1926         for (i = 0; i < log->l_iclog_bufs; i++) {
1927                 down(&iclog->ic_sema);
1928                 up(&iclog->ic_sema);
1929                 iclog = iclog->ic_next;
1930         }
1931
1932         iclog = log->l_iclog;
1933         for (i = 0; i < log->l_iclog_bufs; i++) {
1934                 next_iclog = iclog->ic_next;
1935                 kmem_free(iclog->ic_data);
1936                 kmem_free(iclog);
1937                 iclog = next_iclog;
1938         }
1939
1940         log->l_mp->m_log = NULL;
1941         destroy_workqueue(log->l_ioend_workqueue);
1942         kmem_free(log);
1943 }       /* xlog_dealloc_log */
1944
1945 /*
1946  * Update counters atomically now that memcpy is done.
1947  */
1948 /* ARGSUSED */
1949 static inline void
1950 xlog_state_finish_copy(
1951         struct xlog             *log,
1952         struct xlog_in_core     *iclog,
1953         int                     record_cnt,
1954         int                     copy_bytes)
1955 {
1956         spin_lock(&log->l_icloglock);
1957
1958         be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
1959         iclog->ic_offset += copy_bytes;
1960
1961         spin_unlock(&log->l_icloglock);
1962 }       /* xlog_state_finish_copy */
1963
1964
1965
1966
1967 /*
1968  * print out info relating to regions written which consume
1969  * the reservation
1970  */
1971 void
1972 xlog_print_tic_res(
1973         struct xfs_mount        *mp,
1974         struct xlog_ticket      *ticket)
1975 {
1976         uint i;
1977         uint ophdr_spc = ticket->t_res_num_ophdrs * (uint)sizeof(xlog_op_header_t);
1978
1979         /* match with XLOG_REG_TYPE_* in xfs_log.h */
1980 #define REG_TYPE_STR(type, str) [XLOG_REG_TYPE_##type] = str
1981         static char *res_type_str[] = {
1982             REG_TYPE_STR(BFORMAT, "bformat"),
1983             REG_TYPE_STR(BCHUNK, "bchunk"),
1984             REG_TYPE_STR(EFI_FORMAT, "efi_format"),
1985             REG_TYPE_STR(EFD_FORMAT, "efd_format"),
1986             REG_TYPE_STR(IFORMAT, "iformat"),
1987             REG_TYPE_STR(ICORE, "icore"),
1988             REG_TYPE_STR(IEXT, "iext"),
1989             REG_TYPE_STR(IBROOT, "ibroot"),
1990             REG_TYPE_STR(ILOCAL, "ilocal"),
1991             REG_TYPE_STR(IATTR_EXT, "iattr_ext"),
1992             REG_TYPE_STR(IATTR_BROOT, "iattr_broot"),
1993             REG_TYPE_STR(IATTR_LOCAL, "iattr_local"),
1994             REG_TYPE_STR(QFORMAT, "qformat"),
1995             REG_TYPE_STR(DQUOT, "dquot"),
1996             REG_TYPE_STR(QUOTAOFF, "quotaoff"),
1997             REG_TYPE_STR(LRHEADER, "LR header"),
1998             REG_TYPE_STR(UNMOUNT, "unmount"),
1999             REG_TYPE_STR(COMMIT, "commit"),
2000             REG_TYPE_STR(TRANSHDR, "trans header"),
2001             REG_TYPE_STR(ICREATE, "inode create"),
2002             REG_TYPE_STR(RUI_FORMAT, "rui_format"),
2003             REG_TYPE_STR(RUD_FORMAT, "rud_format"),
2004             REG_TYPE_STR(CUI_FORMAT, "cui_format"),
2005             REG_TYPE_STR(CUD_FORMAT, "cud_format"),
2006             REG_TYPE_STR(BUI_FORMAT, "bui_format"),
2007             REG_TYPE_STR(BUD_FORMAT, "bud_format"),
2008         };
2009         BUILD_BUG_ON(ARRAY_SIZE(res_type_str) != XLOG_REG_TYPE_MAX + 1);
2010 #undef REG_TYPE_STR
2011
2012         xfs_warn(mp, "ticket reservation summary:");
2013         xfs_warn(mp, "  unit res    = %d bytes",
2014                  ticket->t_unit_res);
2015         xfs_warn(mp, "  current res = %d bytes",
2016                  ticket->t_curr_res);
2017         xfs_warn(mp, "  total reg   = %u bytes (o/flow = %u bytes)",
2018                  ticket->t_res_arr_sum, ticket->t_res_o_flow);
2019         xfs_warn(mp, "  ophdrs      = %u (ophdr space = %u bytes)",
2020                  ticket->t_res_num_ophdrs, ophdr_spc);
2021         xfs_warn(mp, "  ophdr + reg = %u bytes",
2022                  ticket->t_res_arr_sum + ticket->t_res_o_flow + ophdr_spc);
2023         xfs_warn(mp, "  num regions = %u",
2024                  ticket->t_res_num);
2025
2026         for (i = 0; i < ticket->t_res_num; i++) {
2027                 uint r_type = ticket->t_res_arr[i].r_type;
2028                 xfs_warn(mp, "region[%u]: %s - %u bytes", i,
2029                             ((r_type <= 0 || r_type > XLOG_REG_TYPE_MAX) ?
2030                             "bad-rtype" : res_type_str[r_type]),
2031                             ticket->t_res_arr[i].r_len);
2032         }
2033 }
2034
2035 /*
2036  * Print a summary of the transaction.
2037  */
2038 void
2039 xlog_print_trans(
2040         struct xfs_trans        *tp)
2041 {
2042         struct xfs_mount        *mp = tp->t_mountp;
2043         struct xfs_log_item     *lip;
2044
2045         /* dump core transaction and ticket info */
2046         xfs_warn(mp, "transaction summary:");
2047         xfs_warn(mp, "  log res   = %d", tp->t_log_res);
2048         xfs_warn(mp, "  log count = %d", tp->t_log_count);
2049         xfs_warn(mp, "  flags     = 0x%x", tp->t_flags);
2050
2051         xlog_print_tic_res(mp, tp->t_ticket);
2052
2053         /* dump each log item */
2054         list_for_each_entry(lip, &tp->t_items, li_trans) {
2055                 struct xfs_log_vec      *lv = lip->li_lv;
2056                 struct xfs_log_iovec    *vec;
2057                 int                     i;
2058
2059                 xfs_warn(mp, "log item: ");
2060                 xfs_warn(mp, "  type    = 0x%x", lip->li_type);
2061                 xfs_warn(mp, "  flags   = 0x%lx", lip->li_flags);
2062                 if (!lv)
2063                         continue;
2064                 xfs_warn(mp, "  niovecs = %d", lv->lv_niovecs);
2065                 xfs_warn(mp, "  size    = %d", lv->lv_size);
2066                 xfs_warn(mp, "  bytes   = %d", lv->lv_bytes);
2067                 xfs_warn(mp, "  buf len = %d", lv->lv_buf_len);
2068
2069                 /* dump each iovec for the log item */
2070                 vec = lv->lv_iovecp;
2071                 for (i = 0; i < lv->lv_niovecs; i++) {
2072                         int dumplen = min(vec->i_len, 32);
2073
2074                         xfs_warn(mp, "  iovec[%d]", i);
2075                         xfs_warn(mp, "    type  = 0x%x", vec->i_type);
2076                         xfs_warn(mp, "    len   = %d", vec->i_len);
2077                         xfs_warn(mp, "    first %d bytes of iovec[%d]:", dumplen, i);
2078                         xfs_hex_dump(vec->i_addr, dumplen);
2079
2080                         vec++;
2081                 }
2082         }
2083 }
2084
2085 /*
2086  * Calculate the potential space needed by the log vector.  Each region gets
2087  * its own xlog_op_header_t and may need to be double word aligned.
2088  */
2089 static int
2090 xlog_write_calc_vec_length(
2091         struct xlog_ticket      *ticket,
2092         struct xfs_log_vec      *log_vector)
2093 {
2094         struct xfs_log_vec      *lv;
2095         int                     headers = 0;
2096         int                     len = 0;
2097         int                     i;
2098
2099         /* acct for start rec of xact */
2100         if (ticket->t_flags & XLOG_TIC_INITED)
2101                 headers++;
2102
2103         for (lv = log_vector; lv; lv = lv->lv_next) {
2104                 /* we don't write ordered log vectors */
2105                 if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED)
2106                         continue;
2107
2108                 headers += lv->lv_niovecs;
2109
2110                 for (i = 0; i < lv->lv_niovecs; i++) {
2111                         struct xfs_log_iovec    *vecp = &lv->lv_iovecp[i];
2112
2113                         len += vecp->i_len;
2114                         xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type);
2115                 }
2116         }
2117
2118         ticket->t_res_num_ophdrs += headers;
2119         len += headers * sizeof(struct xlog_op_header);
2120
2121         return len;
2122 }
2123
2124 /*
2125  * If first write for transaction, insert start record  We can't be trying to
2126  * commit if we are inited.  We can't have any "partial_copy" if we are inited.
2127  */
2128 static int
2129 xlog_write_start_rec(
2130         struct xlog_op_header   *ophdr,
2131         struct xlog_ticket      *ticket)
2132 {
2133         if (!(ticket->t_flags & XLOG_TIC_INITED))
2134                 return 0;
2135
2136         ophdr->oh_tid   = cpu_to_be32(ticket->t_tid);
2137         ophdr->oh_clientid = ticket->t_clientid;
2138         ophdr->oh_len = 0;
2139         ophdr->oh_flags = XLOG_START_TRANS;
2140         ophdr->oh_res2 = 0;
2141
2142         ticket->t_flags &= ~XLOG_TIC_INITED;
2143
2144         return sizeof(struct xlog_op_header);
2145 }
2146
2147 static xlog_op_header_t *
2148 xlog_write_setup_ophdr(
2149         struct xlog             *log,
2150         struct xlog_op_header   *ophdr,
2151         struct xlog_ticket      *ticket,
2152         uint                    flags)
2153 {
2154         ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2155         ophdr->oh_clientid = ticket->t_clientid;
2156         ophdr->oh_res2 = 0;
2157
2158         /* are we copying a commit or unmount record? */
2159         ophdr->oh_flags = flags;
2160
2161         /*
2162          * We've seen logs corrupted with bad transaction client ids.  This
2163          * makes sure that XFS doesn't generate them on.  Turn this into an EIO
2164          * and shut down the filesystem.
2165          */
2166         switch (ophdr->oh_clientid)  {
2167         case XFS_TRANSACTION:
2168         case XFS_VOLUME:
2169         case XFS_LOG:
2170                 break;
2171         default:
2172                 xfs_warn(log->l_mp,
2173                         "Bad XFS transaction clientid 0x%x in ticket "PTR_FMT,
2174                         ophdr->oh_clientid, ticket);
2175                 return NULL;
2176         }
2177
2178         return ophdr;
2179 }
2180
2181 /*
2182  * Set up the parameters of the region copy into the log. This has
2183  * to handle region write split across multiple log buffers - this
2184  * state is kept external to this function so that this code can
2185  * be written in an obvious, self documenting manner.
2186  */
2187 static int
2188 xlog_write_setup_copy(
2189         struct xlog_ticket      *ticket,
2190         struct xlog_op_header   *ophdr,
2191         int                     space_available,
2192         int                     space_required,
2193         int                     *copy_off,
2194         int                     *copy_len,
2195         int                     *last_was_partial_copy,
2196         int                     *bytes_consumed)
2197 {
2198         int                     still_to_copy;
2199
2200         still_to_copy = space_required - *bytes_consumed;
2201         *copy_off = *bytes_consumed;
2202
2203         if (still_to_copy <= space_available) {
2204                 /* write of region completes here */
2205                 *copy_len = still_to_copy;
2206                 ophdr->oh_len = cpu_to_be32(*copy_len);
2207                 if (*last_was_partial_copy)
2208                         ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
2209                 *last_was_partial_copy = 0;
2210                 *bytes_consumed = 0;
2211                 return 0;
2212         }
2213
2214         /* partial write of region, needs extra log op header reservation */
2215         *copy_len = space_available;
2216         ophdr->oh_len = cpu_to_be32(*copy_len);
2217         ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
2218         if (*last_was_partial_copy)
2219                 ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
2220         *bytes_consumed += *copy_len;
2221         (*last_was_partial_copy)++;
2222
2223         /* account for new log op header */
2224         ticket->t_curr_res -= sizeof(struct xlog_op_header);
2225         ticket->t_res_num_ophdrs++;
2226
2227         return sizeof(struct xlog_op_header);
2228 }
2229
2230 static int
2231 xlog_write_copy_finish(
2232         struct xlog             *log,
2233         struct xlog_in_core     *iclog,
2234         uint                    flags,
2235         int                     *record_cnt,
2236         int                     *data_cnt,
2237         int                     *partial_copy,
2238         int                     *partial_copy_len,
2239         int                     log_offset,
2240         struct xlog_in_core     **commit_iclog)
2241 {
2242         if (*partial_copy) {
2243                 /*
2244                  * This iclog has already been marked WANT_SYNC by
2245                  * xlog_state_get_iclog_space.
2246                  */
2247                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2248                 *record_cnt = 0;
2249                 *data_cnt = 0;
2250                 return xlog_state_release_iclog(log, iclog);
2251         }
2252
2253         *partial_copy = 0;
2254         *partial_copy_len = 0;
2255
2256         if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
2257                 /* no more space in this iclog - push it. */
2258                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2259                 *record_cnt = 0;
2260                 *data_cnt = 0;
2261
2262                 spin_lock(&log->l_icloglock);
2263                 xlog_state_want_sync(log, iclog);
2264                 spin_unlock(&log->l_icloglock);
2265
2266                 if (!commit_iclog)
2267                         return xlog_state_release_iclog(log, iclog);
2268                 ASSERT(flags & XLOG_COMMIT_TRANS);
2269                 *commit_iclog = iclog;
2270         }
2271
2272         return 0;
2273 }
2274
2275 /*
2276  * Write some region out to in-core log
2277  *
2278  * This will be called when writing externally provided regions or when
2279  * writing out a commit record for a given transaction.
2280  *
2281  * General algorithm:
2282  *      1. Find total length of this write.  This may include adding to the
2283  *              lengths passed in.
2284  *      2. Check whether we violate the tickets reservation.
2285  *      3. While writing to this iclog
2286  *          A. Reserve as much space in this iclog as can get
2287  *          B. If this is first write, save away start lsn
2288  *          C. While writing this region:
2289  *              1. If first write of transaction, write start record
2290  *              2. Write log operation header (header per region)
2291  *              3. Find out if we can fit entire region into this iclog
2292  *              4. Potentially, verify destination memcpy ptr
2293  *              5. Memcpy (partial) region
2294  *              6. If partial copy, release iclog; otherwise, continue
2295  *                      copying more regions into current iclog
2296  *      4. Mark want sync bit (in simulation mode)
2297  *      5. Release iclog for potential flush to on-disk log.
2298  *
2299  * ERRORS:
2300  * 1.   Panic if reservation is overrun.  This should never happen since
2301  *      reservation amounts are generated internal to the filesystem.
2302  * NOTES:
2303  * 1. Tickets are single threaded data structures.
2304  * 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
2305  *      syncing routine.  When a single log_write region needs to span
2306  *      multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
2307  *      on all log operation writes which don't contain the end of the
2308  *      region.  The XLOG_END_TRANS bit is used for the in-core log
2309  *      operation which contains the end of the continued log_write region.
2310  * 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
2311  *      we don't really know exactly how much space will be used.  As a result,
2312  *      we don't update ic_offset until the end when we know exactly how many
2313  *      bytes have been written out.
2314  */
2315 int
2316 xlog_write(
2317         struct xlog             *log,
2318         struct xfs_log_vec      *log_vector,
2319         struct xlog_ticket      *ticket,
2320         xfs_lsn_t               *start_lsn,
2321         struct xlog_in_core     **commit_iclog,
2322         uint                    flags)
2323 {
2324         struct xlog_in_core     *iclog = NULL;
2325         struct xfs_log_iovec    *vecp;
2326         struct xfs_log_vec      *lv;
2327         int                     len;
2328         int                     index;
2329         int                     partial_copy = 0;
2330         int                     partial_copy_len = 0;
2331         int                     contwr = 0;
2332         int                     record_cnt = 0;
2333         int                     data_cnt = 0;
2334         int                     error;
2335
2336         *start_lsn = 0;
2337
2338         len = xlog_write_calc_vec_length(ticket, log_vector);
2339
2340         /*
2341          * Region headers and bytes are already accounted for.
2342          * We only need to take into account start records and
2343          * split regions in this function.
2344          */
2345         if (ticket->t_flags & XLOG_TIC_INITED)
2346                 ticket->t_curr_res -= sizeof(xlog_op_header_t);
2347
2348         /*
2349          * Commit record headers need to be accounted for. These
2350          * come in as separate writes so are easy to detect.
2351          */
2352         if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS))
2353                 ticket->t_curr_res -= sizeof(xlog_op_header_t);
2354
2355         if (ticket->t_curr_res < 0) {
2356                 xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
2357                      "ctx ticket reservation ran out. Need to up reservation");
2358                 xlog_print_tic_res(log->l_mp, ticket);
2359                 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
2360         }
2361
2362         index = 0;
2363         lv = log_vector;
2364         vecp = lv->lv_iovecp;
2365         while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2366                 void            *ptr;
2367                 int             log_offset;
2368
2369                 error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
2370                                                    &contwr, &log_offset);
2371                 if (error)
2372                         return error;
2373
2374                 ASSERT(log_offset <= iclog->ic_size - 1);
2375                 ptr = iclog->ic_datap + log_offset;
2376
2377                 /* start_lsn is the first lsn written to. That's all we need. */
2378                 if (!*start_lsn)
2379                         *start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2380
2381                 /*
2382                  * This loop writes out as many regions as can fit in the amount
2383                  * of space which was allocated by xlog_state_get_iclog_space().
2384                  */
2385                 while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2386                         struct xfs_log_iovec    *reg;
2387                         struct xlog_op_header   *ophdr;
2388                         int                     start_rec_copy;
2389                         int                     copy_len;
2390                         int                     copy_off;
2391                         bool                    ordered = false;
2392
2393                         /* ordered log vectors have no regions to write */
2394                         if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) {
2395                                 ASSERT(lv->lv_niovecs == 0);
2396                                 ordered = true;
2397                                 goto next_lv;
2398                         }
2399
2400                         reg = &vecp[index];
2401                         ASSERT(reg->i_len % sizeof(int32_t) == 0);
2402                         ASSERT((unsigned long)ptr % sizeof(int32_t) == 0);
2403
2404                         start_rec_copy = xlog_write_start_rec(ptr, ticket);
2405                         if (start_rec_copy) {
2406                                 record_cnt++;
2407                                 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2408                                                    start_rec_copy);
2409                         }
2410
2411                         ophdr = xlog_write_setup_ophdr(log, ptr, ticket, flags);
2412                         if (!ophdr)
2413                                 return -EIO;
2414
2415                         xlog_write_adv_cnt(&ptr, &len, &log_offset,
2416                                            sizeof(struct xlog_op_header));
2417
2418                         len += xlog_write_setup_copy(ticket, ophdr,
2419                                                      iclog->ic_size-log_offset,
2420                                                      reg->i_len,
2421                                                      &copy_off, &copy_len,
2422                                                      &partial_copy,
2423                                                      &partial_copy_len);
2424                         xlog_verify_dest_ptr(log, ptr);
2425
2426                         /*
2427                          * Copy region.
2428                          *
2429                          * Unmount records just log an opheader, so can have
2430                          * empty payloads with no data region to copy. Hence we
2431                          * only copy the payload if the vector says it has data
2432                          * to copy.
2433                          */
2434                         ASSERT(copy_len >= 0);
2435                         if (copy_len > 0) {
2436                                 memcpy(ptr, reg->i_addr + copy_off, copy_len);
2437                                 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2438                                                    copy_len);
2439                         }
2440                         copy_len += start_rec_copy + sizeof(xlog_op_header_t);
2441                         record_cnt++;
2442                         data_cnt += contwr ? copy_len : 0;
2443
2444                         error = xlog_write_copy_finish(log, iclog, flags,
2445                                                        &record_cnt, &data_cnt,
2446                                                        &partial_copy,
2447                                                        &partial_copy_len,
2448                                                        log_offset,
2449                                                        commit_iclog);
2450                         if (error)
2451                                 return error;
2452
2453                         /*
2454                          * if we had a partial copy, we need to get more iclog
2455                          * space but we don't want to increment the region
2456                          * index because there is still more is this region to
2457                          * write.
2458                          *
2459                          * If we completed writing this region, and we flushed
2460                          * the iclog (indicated by resetting of the record
2461                          * count), then we also need to get more log space. If
2462                          * this was the last record, though, we are done and
2463                          * can just return.
2464                          */
2465                         if (partial_copy)
2466                                 break;
2467
2468                         if (++index == lv->lv_niovecs) {
2469 next_lv:
2470                                 lv = lv->lv_next;
2471                                 index = 0;
2472                                 if (lv)
2473                                         vecp = lv->lv_iovecp;
2474                         }
2475                         if (record_cnt == 0 && !ordered) {
2476                                 if (!lv)
2477                                         return 0;
2478                                 break;
2479                         }
2480                 }
2481         }
2482
2483         ASSERT(len == 0);
2484
2485         xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
2486         if (!commit_iclog)
2487                 return xlog_state_release_iclog(log, iclog);
2488
2489         ASSERT(flags & XLOG_COMMIT_TRANS);
2490         *commit_iclog = iclog;
2491         return 0;
2492 }
2493
2494
2495 /*****************************************************************************
2496  *
2497  *              State Machine functions
2498  *
2499  *****************************************************************************
2500  */
2501
2502 /* Clean iclogs starting from the head.  This ordering must be
2503  * maintained, so an iclog doesn't become ACTIVE beyond one that
2504  * is SYNCING.  This is also required to maintain the notion that we use
2505  * a ordered wait queue to hold off would be writers to the log when every
2506  * iclog is trying to sync to disk.
2507  *
2508  * State Change: DIRTY -> ACTIVE
2509  */
2510 STATIC void
2511 xlog_state_clean_log(
2512         struct xlog *log)
2513 {
2514         xlog_in_core_t  *iclog;
2515         int changed = 0;
2516
2517         iclog = log->l_iclog;
2518         do {
2519                 if (iclog->ic_state == XLOG_STATE_DIRTY) {
2520                         iclog->ic_state = XLOG_STATE_ACTIVE;
2521                         iclog->ic_offset       = 0;
2522                         ASSERT(list_empty_careful(&iclog->ic_callbacks));
2523                         /*
2524                          * If the number of ops in this iclog indicate it just
2525                          * contains the dummy transaction, we can
2526                          * change state into IDLE (the second time around).
2527                          * Otherwise we should change the state into
2528                          * NEED a dummy.
2529                          * We don't need to cover the dummy.
2530                          */
2531                         if (!changed &&
2532                            (be32_to_cpu(iclog->ic_header.h_num_logops) ==
2533                                         XLOG_COVER_OPS)) {
2534                                 changed = 1;
2535                         } else {
2536                                 /*
2537                                  * We have two dirty iclogs so start over
2538                                  * This could also be num of ops indicates
2539                                  * this is not the dummy going out.
2540                                  */
2541                                 changed = 2;
2542                         }
2543                         iclog->ic_header.h_num_logops = 0;
2544                         memset(iclog->ic_header.h_cycle_data, 0,
2545                               sizeof(iclog->ic_header.h_cycle_data));
2546                         iclog->ic_header.h_lsn = 0;
2547                 } else if (iclog->ic_state == XLOG_STATE_ACTIVE)
2548                         /* do nothing */;
2549                 else
2550                         break;  /* stop cleaning */
2551                 iclog = iclog->ic_next;
2552         } while (iclog != log->l_iclog);
2553
2554         /* log is locked when we are called */
2555         /*
2556          * Change state for the dummy log recording.
2557          * We usually go to NEED. But we go to NEED2 if the changed indicates
2558          * we are done writing the dummy record.
2559          * If we are done with the second dummy recored (DONE2), then
2560          * we go to IDLE.
2561          */
2562         if (changed) {
2563                 switch (log->l_covered_state) {
2564                 case XLOG_STATE_COVER_IDLE:
2565                 case XLOG_STATE_COVER_NEED:
2566                 case XLOG_STATE_COVER_NEED2:
2567                         log->l_covered_state = XLOG_STATE_COVER_NEED;
2568                         break;
2569
2570                 case XLOG_STATE_COVER_DONE:
2571                         if (changed == 1)
2572                                 log->l_covered_state = XLOG_STATE_COVER_NEED2;
2573                         else
2574                                 log->l_covered_state = XLOG_STATE_COVER_NEED;
2575                         break;
2576
2577                 case XLOG_STATE_COVER_DONE2:
2578                         if (changed == 1)
2579                                 log->l_covered_state = XLOG_STATE_COVER_IDLE;
2580                         else
2581                                 log->l_covered_state = XLOG_STATE_COVER_NEED;
2582                         break;
2583
2584                 default:
2585                         ASSERT(0);
2586                 }
2587         }
2588 }       /* xlog_state_clean_log */
2589
2590 STATIC xfs_lsn_t
2591 xlog_get_lowest_lsn(
2592         struct xlog             *log)
2593 {
2594         struct xlog_in_core     *iclog = log->l_iclog;
2595         xfs_lsn_t               lowest_lsn = 0, lsn;
2596
2597         do {
2598                 if (iclog->ic_state & (XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY))
2599                         continue;
2600
2601                 lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2602                 if ((lsn && !lowest_lsn) || XFS_LSN_CMP(lsn, lowest_lsn) < 0)
2603                         lowest_lsn = lsn;
2604         } while ((iclog = iclog->ic_next) != log->l_iclog);
2605
2606         return lowest_lsn;
2607 }
2608
2609 STATIC void
2610 xlog_state_do_callback(
2611         struct xlog             *log,
2612         bool                    aborted,
2613         struct xlog_in_core     *ciclog)
2614 {
2615         xlog_in_core_t     *iclog;
2616         xlog_in_core_t     *first_iclog;        /* used to know when we've
2617                                                  * processed all iclogs once */
2618         int                flushcnt = 0;
2619         xfs_lsn_t          lowest_lsn;
2620         int                ioerrors;    /* counter: iclogs with errors */
2621         int                loopdidcallbacks; /* flag: inner loop did callbacks*/
2622         int                funcdidcallbacks; /* flag: function did callbacks */
2623         int                repeats;     /* for issuing console warnings if
2624                                          * looping too many times */
2625         int                wake = 0;
2626
2627         spin_lock(&log->l_icloglock);
2628         first_iclog = iclog = log->l_iclog;
2629         ioerrors = 0;
2630         funcdidcallbacks = 0;
2631         repeats = 0;
2632
2633         do {
2634                 /*
2635                  * Scan all iclogs starting with the one pointed to by the
2636                  * log.  Reset this starting point each time the log is
2637                  * unlocked (during callbacks).
2638                  *
2639                  * Keep looping through iclogs until one full pass is made
2640                  * without running any callbacks.
2641                  */
2642                 first_iclog = log->l_iclog;
2643                 iclog = log->l_iclog;
2644                 loopdidcallbacks = 0;
2645                 repeats++;
2646
2647                 do {
2648
2649                         /* skip all iclogs in the ACTIVE & DIRTY states */
2650                         if (iclog->ic_state &
2651                             (XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY)) {
2652                                 iclog = iclog->ic_next;
2653                                 continue;
2654                         }
2655
2656                         /*
2657                          * Between marking a filesystem SHUTDOWN and stopping
2658                          * the log, we do flush all iclogs to disk (if there
2659                          * wasn't a log I/O error). So, we do want things to
2660                          * go smoothly in case of just a SHUTDOWN  w/o a
2661                          * LOG_IO_ERROR.
2662                          */
2663                         if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
2664                                 /*
2665                                  * Can only perform callbacks in order.  Since
2666                                  * this iclog is not in the DONE_SYNC/
2667                                  * DO_CALLBACK state, we skip the rest and
2668                                  * just try to clean up.  If we set our iclog
2669                                  * to DO_CALLBACK, we will not process it when
2670                                  * we retry since a previous iclog is in the
2671                                  * CALLBACK and the state cannot change since
2672                                  * we are holding the l_icloglock.
2673                                  */
2674                                 if (!(iclog->ic_state &
2675                                         (XLOG_STATE_DONE_SYNC |
2676                                                  XLOG_STATE_DO_CALLBACK))) {
2677                                         if (ciclog && (ciclog->ic_state ==
2678                                                         XLOG_STATE_DONE_SYNC)) {
2679                                                 ciclog->ic_state = XLOG_STATE_DO_CALLBACK;
2680                                         }
2681                                         break;
2682                                 }
2683                                 /*
2684                                  * We now have an iclog that is in either the
2685                                  * DO_CALLBACK or DONE_SYNC states. The other
2686                                  * states (WANT_SYNC, SYNCING, or CALLBACK were
2687                                  * caught by the above if and are going to
2688                                  * clean (i.e. we aren't doing their callbacks)
2689                                  * see the above if.
2690                                  */
2691
2692                                 /*
2693                                  * We will do one more check here to see if we
2694                                  * have chased our tail around.
2695                                  */
2696
2697                                 lowest_lsn = xlog_get_lowest_lsn(log);
2698                                 if (lowest_lsn &&
2699                                     XFS_LSN_CMP(lowest_lsn,
2700                                                 be64_to_cpu(iclog->ic_header.h_lsn)) < 0) {
2701                                         iclog = iclog->ic_next;
2702                                         continue; /* Leave this iclog for
2703                                                    * another thread */
2704                                 }
2705
2706                                 iclog->ic_state = XLOG_STATE_CALLBACK;
2707
2708
2709                                 /*
2710                                  * Completion of a iclog IO does not imply that
2711                                  * a transaction has completed, as transactions
2712                                  * can be large enough to span many iclogs. We
2713                                  * cannot change the tail of the log half way
2714                                  * through a transaction as this may be the only
2715                                  * transaction in the log and moving th etail to
2716                                  * point to the middle of it will prevent
2717                                  * recovery from finding the start of the
2718                                  * transaction. Hence we should only update the
2719                                  * last_sync_lsn if this iclog contains
2720                                  * transaction completion callbacks on it.
2721                                  *
2722                                  * We have to do this before we drop the
2723                                  * icloglock to ensure we are the only one that
2724                                  * can update it.
2725                                  */
2726                                 ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
2727                                         be64_to_cpu(iclog->ic_header.h_lsn)) <= 0);
2728                                 if (!list_empty_careful(&iclog->ic_callbacks))
2729                                         atomic64_set(&log->l_last_sync_lsn,
2730                                                 be64_to_cpu(iclog->ic_header.h_lsn));
2731
2732                         } else
2733                                 ioerrors++;
2734
2735                         spin_unlock(&log->l_icloglock);
2736
2737                         /*
2738                          * Keep processing entries in the callback list until
2739                          * we come around and it is empty.  We need to
2740                          * atomically see that the list is empty and change the
2741                          * state to DIRTY so that we don't miss any more
2742                          * callbacks being added.
2743                          */
2744                         spin_lock(&iclog->ic_callback_lock);
2745                         while (!list_empty(&iclog->ic_callbacks)) {
2746                                 LIST_HEAD(tmp);
2747
2748                                 list_splice_init(&iclog->ic_callbacks, &tmp);
2749
2750                                 spin_unlock(&iclog->ic_callback_lock);
2751                                 xlog_cil_process_committed(&tmp, aborted);
2752                                 spin_lock(&iclog->ic_callback_lock);
2753                         }
2754
2755                         loopdidcallbacks++;
2756                         funcdidcallbacks++;
2757
2758                         spin_lock(&log->l_icloglock);
2759                         spin_unlock(&iclog->ic_callback_lock);
2760                         if (!(iclog->ic_state & XLOG_STATE_IOERROR))
2761                                 iclog->ic_state = XLOG_STATE_DIRTY;
2762
2763                         /*
2764                          * Transition from DIRTY to ACTIVE if applicable.
2765                          * NOP if STATE_IOERROR.
2766                          */
2767                         xlog_state_clean_log(log);
2768
2769                         /* wake up threads waiting in xfs_log_force() */
2770                         wake_up_all(&iclog->ic_force_wait);
2771
2772                         iclog = iclog->ic_next;
2773                 } while (first_iclog != iclog);
2774
2775                 if (repeats > 5000) {
2776                         flushcnt += repeats;
2777                         repeats = 0;
2778                         xfs_warn(log->l_mp,
2779                                 "%s: possible infinite loop (%d iterations)",
2780                                 __func__, flushcnt);
2781                 }
2782         } while (!ioerrors && loopdidcallbacks);
2783
2784 #ifdef DEBUG
2785         /*
2786          * Make one last gasp attempt to see if iclogs are being left in limbo.
2787          * If the above loop finds an iclog earlier than the current iclog and
2788          * in one of the syncing states, the current iclog is put into
2789          * DO_CALLBACK and the callbacks are deferred to the completion of the
2790          * earlier iclog. Walk the iclogs in order and make sure that no iclog
2791          * is in DO_CALLBACK unless an earlier iclog is in one of the syncing
2792          * states.
2793          *
2794          * Note that SYNCING|IOABORT is a valid state so we cannot just check
2795          * for ic_state == SYNCING.
2796          */
2797         if (funcdidcallbacks) {
2798                 first_iclog = iclog = log->l_iclog;
2799                 do {
2800                         ASSERT(iclog->ic_state != XLOG_STATE_DO_CALLBACK);
2801                         /*
2802                          * Terminate the loop if iclogs are found in states
2803                          * which will cause other threads to clean up iclogs.
2804                          *
2805                          * SYNCING - i/o completion will go through logs
2806                          * DONE_SYNC - interrupt thread should be waiting for
2807                          *              l_icloglock
2808                          * IOERROR - give up hope all ye who enter here
2809                          */
2810                         if (iclog->ic_state == XLOG_STATE_WANT_SYNC ||
2811                             iclog->ic_state & XLOG_STATE_SYNCING ||
2812                             iclog->ic_state == XLOG_STATE_DONE_SYNC ||
2813                             iclog->ic_state == XLOG_STATE_IOERROR )
2814                                 break;
2815                         iclog = iclog->ic_next;
2816                 } while (first_iclog != iclog);
2817         }
2818 #endif
2819
2820         if (log->l_iclog->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_IOERROR))
2821                 wake = 1;
2822         spin_unlock(&log->l_icloglock);
2823
2824         if (wake)
2825                 wake_up_all(&log->l_flush_wait);
2826 }
2827
2828
2829 /*
2830  * Finish transitioning this iclog to the dirty state.
2831  *
2832  * Make sure that we completely execute this routine only when this is
2833  * the last call to the iclog.  There is a good chance that iclog flushes,
2834  * when we reach the end of the physical log, get turned into 2 separate
2835  * calls to bwrite.  Hence, one iclog flush could generate two calls to this
2836  * routine.  By using the reference count bwritecnt, we guarantee that only
2837  * the second completion goes through.
2838  *
2839  * Callbacks could take time, so they are done outside the scope of the
2840  * global state machine log lock.
2841  */
2842 STATIC void
2843 xlog_state_done_syncing(
2844         struct xlog_in_core     *iclog,
2845         bool                    aborted)
2846 {
2847         struct xlog             *log = iclog->ic_log;
2848
2849         spin_lock(&log->l_icloglock);
2850
2851         ASSERT(iclog->ic_state == XLOG_STATE_SYNCING ||
2852                iclog->ic_state == XLOG_STATE_IOERROR);
2853         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
2854
2855         /*
2856          * If we got an error, either on the first buffer, or in the case of
2857          * split log writes, on the second, we mark ALL iclogs STATE_IOERROR,
2858          * and none should ever be attempted to be written to disk
2859          * again.
2860          */
2861         if (iclog->ic_state != XLOG_STATE_IOERROR)
2862                 iclog->ic_state = XLOG_STATE_DONE_SYNC;
2863
2864         /*
2865          * Someone could be sleeping prior to writing out the next
2866          * iclog buffer, we wake them all, one will get to do the
2867          * I/O, the others get to wait for the result.
2868          */
2869         wake_up_all(&iclog->ic_write_wait);
2870         spin_unlock(&log->l_icloglock);
2871         xlog_state_do_callback(log, aborted, iclog);    /* also cleans log */
2872 }       /* xlog_state_done_syncing */
2873
2874
2875 /*
2876  * If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
2877  * sleep.  We wait on the flush queue on the head iclog as that should be
2878  * the first iclog to complete flushing. Hence if all iclogs are syncing,
2879  * we will wait here and all new writes will sleep until a sync completes.
2880  *
2881  * The in-core logs are used in a circular fashion. They are not used
2882  * out-of-order even when an iclog past the head is free.
2883  *
2884  * return:
2885  *      * log_offset where xlog_write() can start writing into the in-core
2886  *              log's data space.
2887  *      * in-core log pointer to which xlog_write() should write.
2888  *      * boolean indicating this is a continued write to an in-core log.
2889  *              If this is the last write, then the in-core log's offset field
2890  *              needs to be incremented, depending on the amount of data which
2891  *              is copied.
2892  */
2893 STATIC int
2894 xlog_state_get_iclog_space(
2895         struct xlog             *log,
2896         int                     len,
2897         struct xlog_in_core     **iclogp,
2898         struct xlog_ticket      *ticket,
2899         int                     *continued_write,
2900         int                     *logoffsetp)
2901 {
2902         int               log_offset;
2903         xlog_rec_header_t *head;
2904         xlog_in_core_t    *iclog;
2905         int               error;
2906
2907 restart:
2908         spin_lock(&log->l_icloglock);
2909         if (XLOG_FORCED_SHUTDOWN(log)) {
2910                 spin_unlock(&log->l_icloglock);
2911                 return -EIO;
2912         }
2913
2914         iclog = log->l_iclog;
2915         if (iclog->ic_state != XLOG_STATE_ACTIVE) {
2916                 XFS_STATS_INC(log->l_mp, xs_log_noiclogs);
2917
2918                 /* Wait for log writes to have flushed */
2919                 xlog_wait(&log->l_flush_wait, &log->l_icloglock);
2920                 goto restart;
2921         }
2922
2923         head = &iclog->ic_header;
2924
2925         atomic_inc(&iclog->ic_refcnt);  /* prevents sync */
2926         log_offset = iclog->ic_offset;
2927
2928         /* On the 1st write to an iclog, figure out lsn.  This works
2929          * if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
2930          * committing to.  If the offset is set, that's how many blocks
2931          * must be written.
2932          */
2933         if (log_offset == 0) {
2934                 ticket->t_curr_res -= log->l_iclog_hsize;
2935                 xlog_tic_add_region(ticket,
2936                                     log->l_iclog_hsize,
2937                                     XLOG_REG_TYPE_LRHEADER);
2938                 head->h_cycle = cpu_to_be32(log->l_curr_cycle);
2939                 head->h_lsn = cpu_to_be64(
2940                         xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
2941                 ASSERT(log->l_curr_block >= 0);
2942         }
2943
2944         /* If there is enough room to write everything, then do it.  Otherwise,
2945          * claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
2946          * bit is on, so this will get flushed out.  Don't update ic_offset
2947          * until you know exactly how many bytes get copied.  Therefore, wait
2948          * until later to update ic_offset.
2949          *
2950          * xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
2951          * can fit into remaining data section.
2952          */
2953         if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
2954                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2955
2956                 /*
2957                  * If I'm the only one writing to this iclog, sync it to disk.
2958                  * We need to do an atomic compare and decrement here to avoid
2959                  * racing with concurrent atomic_dec_and_lock() calls in
2960                  * xlog_state_release_iclog() when there is more than one
2961                  * reference to the iclog.
2962                  */
2963                 if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1)) {
2964                         /* we are the only one */
2965                         spin_unlock(&log->l_icloglock);
2966                         error = xlog_state_release_iclog(log, iclog);
2967                         if (error)
2968                                 return error;
2969                 } else {
2970                         spin_unlock(&log->l_icloglock);
2971                 }
2972                 goto restart;
2973         }
2974
2975         /* Do we have enough room to write the full amount in the remainder
2976          * of this iclog?  Or must we continue a write on the next iclog and
2977          * mark this iclog as completely taken?  In the case where we switch
2978          * iclogs (to mark it taken), this particular iclog will release/sync
2979          * to disk in xlog_write().
2980          */
2981         if (len <= iclog->ic_size - iclog->ic_offset) {
2982                 *continued_write = 0;
2983                 iclog->ic_offset += len;
2984         } else {
2985                 *continued_write = 1;
2986                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2987         }
2988         *iclogp = iclog;
2989
2990         ASSERT(iclog->ic_offset <= iclog->ic_size);
2991         spin_unlock(&log->l_icloglock);
2992
2993         *logoffsetp = log_offset;
2994         return 0;
2995 }       /* xlog_state_get_iclog_space */
2996
2997 /* The first cnt-1 times through here we don't need to
2998  * move the grant write head because the permanent
2999  * reservation has reserved cnt times the unit amount.
3000  * Release part of current permanent unit reservation and
3001  * reset current reservation to be one units worth.  Also
3002  * move grant reservation head forward.
3003  */
3004 STATIC void
3005 xlog_regrant_reserve_log_space(
3006         struct xlog             *log,
3007         struct xlog_ticket      *ticket)
3008 {
3009         trace_xfs_log_regrant_reserve_enter(log, ticket);
3010
3011         if (ticket->t_cnt > 0)
3012                 ticket->t_cnt--;
3013
3014         xlog_grant_sub_space(log, &log->l_reserve_head.grant,
3015                                         ticket->t_curr_res);
3016         xlog_grant_sub_space(log, &log->l_write_head.grant,
3017                                         ticket->t_curr_res);
3018         ticket->t_curr_res = ticket->t_unit_res;
3019         xlog_tic_reset_res(ticket);
3020
3021         trace_xfs_log_regrant_reserve_sub(log, ticket);
3022
3023         /* just return if we still have some of the pre-reserved space */
3024         if (ticket->t_cnt > 0)
3025                 return;
3026
3027         xlog_grant_add_space(log, &log->l_reserve_head.grant,
3028                                         ticket->t_unit_res);
3029
3030         trace_xfs_log_regrant_reserve_exit(log, ticket);
3031
3032         ticket->t_curr_res = ticket->t_unit_res;
3033         xlog_tic_reset_res(ticket);
3034 }       /* xlog_regrant_reserve_log_space */
3035
3036
3037 /*
3038  * Give back the space left from a reservation.
3039  *
3040  * All the information we need to make a correct determination of space left
3041  * is present.  For non-permanent reservations, things are quite easy.  The
3042  * count should have been decremented to zero.  We only need to deal with the
3043  * space remaining in the current reservation part of the ticket.  If the
3044  * ticket contains a permanent reservation, there may be left over space which
3045  * needs to be released.  A count of N means that N-1 refills of the current
3046  * reservation can be done before we need to ask for more space.  The first
3047  * one goes to fill up the first current reservation.  Once we run out of
3048  * space, the count will stay at zero and the only space remaining will be
3049  * in the current reservation field.
3050  */
3051 STATIC void
3052 xlog_ungrant_log_space(
3053         struct xlog             *log,
3054         struct xlog_ticket      *ticket)
3055 {
3056         int     bytes;
3057
3058         if (ticket->t_cnt > 0)
3059                 ticket->t_cnt--;
3060
3061         trace_xfs_log_ungrant_enter(log, ticket);
3062         trace_xfs_log_ungrant_sub(log, ticket);
3063
3064         /*
3065          * If this is a permanent reservation ticket, we may be able to free
3066          * up more space based on the remaining count.
3067          */
3068         bytes = ticket->t_curr_res;
3069         if (ticket->t_cnt > 0) {
3070                 ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
3071                 bytes += ticket->t_unit_res*ticket->t_cnt;
3072         }
3073
3074         xlog_grant_sub_space(log, &log->l_reserve_head.grant, bytes);
3075         xlog_grant_sub_space(log, &log->l_write_head.grant, bytes);
3076
3077         trace_xfs_log_ungrant_exit(log, ticket);
3078
3079         xfs_log_space_wake(log->l_mp);
3080 }
3081
3082 /*
3083  * Flush iclog to disk if this is the last reference to the given iclog and
3084  * the WANT_SYNC bit is set.
3085  *
3086  * When this function is entered, the iclog is not necessarily in the
3087  * WANT_SYNC state.  It may be sitting around waiting to get filled.
3088  *
3089  *
3090  */
3091 STATIC int
3092 xlog_state_release_iclog(
3093         struct xlog             *log,
3094         struct xlog_in_core     *iclog)
3095 {
3096         int             sync = 0;       /* do we sync? */
3097
3098         if (iclog->ic_state & XLOG_STATE_IOERROR)
3099                 return -EIO;
3100
3101         ASSERT(atomic_read(&iclog->ic_refcnt) > 0);
3102         if (!atomic_dec_and_lock(&iclog->ic_refcnt, &log->l_icloglock))
3103                 return 0;
3104
3105         if (iclog->ic_state & XLOG_STATE_IOERROR) {
3106                 spin_unlock(&log->l_icloglock);
3107                 return -EIO;
3108         }
3109         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE ||
3110                iclog->ic_state == XLOG_STATE_WANT_SYNC);
3111
3112         if (iclog->ic_state == XLOG_STATE_WANT_SYNC) {
3113                 /* update tail before writing to iclog */
3114                 xfs_lsn_t tail_lsn = xlog_assign_tail_lsn(log->l_mp);
3115                 sync++;
3116                 iclog->ic_state = XLOG_STATE_SYNCING;
3117                 iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn);
3118                 xlog_verify_tail_lsn(log, iclog, tail_lsn);
3119                 /* cycle incremented when incrementing curr_block */
3120         }
3121         spin_unlock(&log->l_icloglock);
3122
3123         /*
3124          * We let the log lock go, so it's possible that we hit a log I/O
3125          * error or some other SHUTDOWN condition that marks the iclog
3126          * as XLOG_STATE_IOERROR before the bwrite. However, we know that
3127          * this iclog has consistent data, so we ignore IOERROR
3128          * flags after this point.
3129          */
3130         if (sync)
3131                 xlog_sync(log, iclog);
3132         return 0;
3133 }       /* xlog_state_release_iclog */
3134
3135
3136 /*
3137  * This routine will mark the current iclog in the ring as WANT_SYNC
3138  * and move the current iclog pointer to the next iclog in the ring.
3139  * When this routine is called from xlog_state_get_iclog_space(), the
3140  * exact size of the iclog has not yet been determined.  All we know is
3141  * that every data block.  We have run out of space in this log record.
3142  */
3143 STATIC void
3144 xlog_state_switch_iclogs(
3145         struct xlog             *log,
3146         struct xlog_in_core     *iclog,
3147         int                     eventual_size)
3148 {
3149         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
3150         if (!eventual_size)
3151                 eventual_size = iclog->ic_offset;
3152         iclog->ic_state = XLOG_STATE_WANT_SYNC;
3153         iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
3154         log->l_prev_block = log->l_curr_block;
3155         log->l_prev_cycle = log->l_curr_cycle;
3156
3157         /* roll log?: ic_offset changed later */
3158         log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
3159
3160         /* Round up to next log-sunit */
3161         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
3162             log->l_mp->m_sb.sb_logsunit > 1) {
3163                 uint32_t sunit_bb = BTOBB(log->l_mp->m_sb.sb_logsunit);
3164                 log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
3165         }
3166
3167         if (log->l_curr_block >= log->l_logBBsize) {
3168                 /*
3169                  * Rewind the current block before the cycle is bumped to make
3170                  * sure that the combined LSN never transiently moves forward
3171                  * when the log wraps to the next cycle. This is to support the
3172                  * unlocked sample of these fields from xlog_valid_lsn(). Most
3173                  * other cases should acquire l_icloglock.
3174                  */
3175                 log->l_curr_block -= log->l_logBBsize;
3176                 ASSERT(log->l_curr_block >= 0);
3177                 smp_wmb();
3178                 log->l_curr_cycle++;
3179                 if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
3180                         log->l_curr_cycle++;
3181         }
3182         ASSERT(iclog == log->l_iclog);
3183         log->l_iclog = iclog->ic_next;
3184 }       /* xlog_state_switch_iclogs */
3185
3186 /*
3187  * Write out all data in the in-core log as of this exact moment in time.
3188  *
3189  * Data may be written to the in-core log during this call.  However,
3190  * we don't guarantee this data will be written out.  A change from past
3191  * implementation means this routine will *not* write out zero length LRs.
3192  *
3193  * Basically, we try and perform an intelligent scan of the in-core logs.
3194  * If we determine there is no flushable data, we just return.  There is no
3195  * flushable data if:
3196  *
3197  *      1. the current iclog is active and has no data; the previous iclog
3198  *              is in the active or dirty state.
3199  *      2. the current iclog is drity, and the previous iclog is in the
3200  *              active or dirty state.
3201  *
3202  * We may sleep if:
3203  *
3204  *      1. the current iclog is not in the active nor dirty state.
3205  *      2. the current iclog dirty, and the previous iclog is not in the
3206  *              active nor dirty state.
3207  *      3. the current iclog is active, and there is another thread writing
3208  *              to this particular iclog.
3209  *      4. a) the current iclog is active and has no other writers
3210  *         b) when we return from flushing out this iclog, it is still
3211  *              not in the active nor dirty state.
3212  */
3213 int
3214 xfs_log_force(
3215         struct xfs_mount        *mp,
3216         uint                    flags)
3217 {
3218         struct xlog             *log = mp->m_log;
3219         struct xlog_in_core     *iclog;
3220         xfs_lsn_t               lsn;
3221
3222         XFS_STATS_INC(mp, xs_log_force);
3223         trace_xfs_log_force(mp, 0, _RET_IP_);
3224
3225         xlog_cil_force(log);
3226
3227         spin_lock(&log->l_icloglock);
3228         iclog = log->l_iclog;
3229         if (iclog->ic_state & XLOG_STATE_IOERROR)
3230                 goto out_error;
3231
3232         if (iclog->ic_state == XLOG_STATE_DIRTY ||
3233             (iclog->ic_state == XLOG_STATE_ACTIVE &&
3234              atomic_read(&iclog->ic_refcnt) == 0 && iclog->ic_offset == 0)) {
3235                 /*
3236                  * If the head is dirty or (active and empty), then we need to
3237                  * look at the previous iclog.
3238                  *
3239                  * If the previous iclog is active or dirty we are done.  There
3240                  * is nothing to sync out. Otherwise, we attach ourselves to the
3241                  * previous iclog and go to sleep.
3242                  */
3243                 iclog = iclog->ic_prev;
3244                 if (iclog->ic_state == XLOG_STATE_ACTIVE ||
3245                     iclog->ic_state == XLOG_STATE_DIRTY)
3246                         goto out_unlock;
3247         } else if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3248                 if (atomic_read(&iclog->ic_refcnt) == 0) {
3249                         /*
3250                          * We are the only one with access to this iclog.
3251                          *
3252                          * Flush it out now.  There should be a roundoff of zero
3253                          * to show that someone has already taken care of the
3254                          * roundoff from the previous sync.
3255                          */
3256                         atomic_inc(&iclog->ic_refcnt);
3257                         lsn = be64_to_cpu(iclog->ic_header.h_lsn);
3258                         xlog_state_switch_iclogs(log, iclog, 0);
3259                         spin_unlock(&log->l_icloglock);
3260
3261                         if (xlog_state_release_iclog(log, iclog))
3262                                 return -EIO;
3263
3264                         spin_lock(&log->l_icloglock);
3265                         if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn ||
3266                             iclog->ic_state == XLOG_STATE_DIRTY)
3267                                 goto out_unlock;
3268                 } else {
3269                         /*
3270                          * Someone else is writing to this iclog.
3271                          *
3272                          * Use its call to flush out the data.  However, the
3273                          * other thread may not force out this LR, so we mark
3274                          * it WANT_SYNC.
3275                          */
3276                         xlog_state_switch_iclogs(log, iclog, 0);
3277                 }
3278         } else {
3279                 /*
3280                  * If the head iclog is not active nor dirty, we just attach
3281                  * ourselves to the head and go to sleep if necessary.
3282                  */
3283                 ;
3284         }
3285
3286         if (!(flags & XFS_LOG_SYNC))
3287                 goto out_unlock;
3288
3289         if (iclog->ic_state & XLOG_STATE_IOERROR)
3290                 goto out_error;
3291         XFS_STATS_INC(mp, xs_log_force_sleep);
3292         xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
3293         if (iclog->ic_state & XLOG_STATE_IOERROR)
3294                 return -EIO;
3295         return 0;
3296
3297 out_unlock:
3298         spin_unlock(&log->l_icloglock);
3299         return 0;
3300 out_error:
3301         spin_unlock(&log->l_icloglock);
3302         return -EIO;
3303 }
3304
3305 static int
3306 __xfs_log_force_lsn(
3307         struct xfs_mount        *mp,
3308         xfs_lsn_t               lsn,
3309         uint                    flags,
3310         int                     *log_flushed,
3311         bool                    already_slept)
3312 {
3313         struct xlog             *log = mp->m_log;
3314         struct xlog_in_core     *iclog;
3315
3316         spin_lock(&log->l_icloglock);
3317         iclog = log->l_iclog;
3318         if (iclog->ic_state & XLOG_STATE_IOERROR)
3319                 goto out_error;
3320
3321         while (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
3322                 iclog = iclog->ic_next;
3323                 if (iclog == log->l_iclog)
3324                         goto out_unlock;
3325         }
3326
3327         if (iclog->ic_state == XLOG_STATE_DIRTY)
3328                 goto out_unlock;
3329
3330         if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3331                 /*
3332                  * We sleep here if we haven't already slept (e.g. this is the
3333                  * first time we've looked at the correct iclog buf) and the
3334                  * buffer before us is going to be sync'ed.  The reason for this
3335                  * is that if we are doing sync transactions here, by waiting
3336                  * for the previous I/O to complete, we can allow a few more
3337                  * transactions into this iclog before we close it down.
3338                  *
3339                  * Otherwise, we mark the buffer WANT_SYNC, and bump up the
3340                  * refcnt so we can release the log (which drops the ref count).
3341                  * The state switch keeps new transaction commits from using
3342                  * this buffer.  When the current commits finish writing into
3343                  * the buffer, the refcount will drop to zero and the buffer
3344                  * will go out then.
3345                  */
3346                 if (!already_slept &&
3347                     (iclog->ic_prev->ic_state &
3348                      (XLOG_STATE_WANT_SYNC | XLOG_STATE_SYNCING))) {
3349                         ASSERT(!(iclog->ic_state & XLOG_STATE_IOERROR));
3350
3351                         XFS_STATS_INC(mp, xs_log_force_sleep);
3352
3353                         xlog_wait(&iclog->ic_prev->ic_write_wait,
3354                                         &log->l_icloglock);
3355                         return -EAGAIN;
3356                 }
3357                 atomic_inc(&iclog->ic_refcnt);
3358                 xlog_state_switch_iclogs(log, iclog, 0);
3359                 spin_unlock(&log->l_icloglock);
3360                 if (xlog_state_release_iclog(log, iclog))
3361                         return -EIO;
3362                 if (log_flushed)
3363                         *log_flushed = 1;
3364                 spin_lock(&log->l_icloglock);
3365         }
3366
3367         if (!(flags & XFS_LOG_SYNC) ||
3368             (iclog->ic_state & (XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY)))
3369                 goto out_unlock;
3370
3371         if (iclog->ic_state & XLOG_STATE_IOERROR)
3372                 goto out_error;
3373
3374         XFS_STATS_INC(mp, xs_log_force_sleep);
3375         xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
3376         if (iclog->ic_state & XLOG_STATE_IOERROR)
3377                 return -EIO;
3378         return 0;
3379
3380 out_unlock:
3381         spin_unlock(&log->l_icloglock);
3382         return 0;
3383 out_error:
3384         spin_unlock(&log->l_icloglock);
3385         return -EIO;
3386 }
3387
3388 /*
3389  * Force the in-core log to disk for a specific LSN.
3390  *
3391  * Find in-core log with lsn.
3392  *      If it is in the DIRTY state, just return.
3393  *      If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
3394  *              state and go to sleep or return.
3395  *      If it is in any other state, go to sleep or return.
3396  *
3397  * Synchronous forces are implemented with a wait queue.  All callers trying
3398  * to force a given lsn to disk must wait on the queue attached to the
3399  * specific in-core log.  When given in-core log finally completes its write
3400  * to disk, that thread will wake up all threads waiting on the queue.
3401  */
3402 int
3403 xfs_log_force_lsn(
3404         struct xfs_mount        *mp,
3405         xfs_lsn_t               lsn,
3406         uint                    flags,
3407         int                     *log_flushed)
3408 {
3409         int                     ret;
3410         ASSERT(lsn != 0);
3411
3412         XFS_STATS_INC(mp, xs_log_force);
3413         trace_xfs_log_force(mp, lsn, _RET_IP_);
3414
3415         lsn = xlog_cil_force_lsn(mp->m_log, lsn);
3416         if (lsn == NULLCOMMITLSN)
3417                 return 0;
3418
3419         ret = __xfs_log_force_lsn(mp, lsn, flags, log_flushed, false);
3420         if (ret == -EAGAIN)
3421                 ret = __xfs_log_force_lsn(mp, lsn, flags, log_flushed, true);
3422         return ret;
3423 }
3424
3425 /*
3426  * Called when we want to mark the current iclog as being ready to sync to
3427  * disk.
3428  */
3429 STATIC void
3430 xlog_state_want_sync(
3431         struct xlog             *log,
3432         struct xlog_in_core     *iclog)
3433 {
3434         assert_spin_locked(&log->l_icloglock);
3435
3436         if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3437                 xlog_state_switch_iclogs(log, iclog, 0);
3438         } else {
3439                 ASSERT(iclog->ic_state &
3440                         (XLOG_STATE_WANT_SYNC|XLOG_STATE_IOERROR));
3441         }
3442 }
3443
3444
3445 /*****************************************************************************
3446  *
3447  *              TICKET functions
3448  *
3449  *****************************************************************************
3450  */
3451
3452 /*
3453  * Free a used ticket when its refcount falls to zero.
3454  */
3455 void
3456 xfs_log_ticket_put(
3457         xlog_ticket_t   *ticket)
3458 {
3459         ASSERT(atomic_read(&ticket->t_ref) > 0);
3460         if (atomic_dec_and_test(&ticket->t_ref))
3461                 kmem_zone_free(xfs_log_ticket_zone, ticket);
3462 }
3463
3464 xlog_ticket_t *
3465 xfs_log_ticket_get(
3466         xlog_ticket_t   *ticket)
3467 {
3468         ASSERT(atomic_read(&ticket->t_ref) > 0);
3469         atomic_inc(&ticket->t_ref);
3470         return ticket;
3471 }
3472
3473 /*
3474  * Figure out the total log space unit (in bytes) that would be
3475  * required for a log ticket.
3476  */
3477 int
3478 xfs_log_calc_unit_res(
3479         struct xfs_mount        *mp,
3480         int                     unit_bytes)
3481 {
3482         struct xlog             *log = mp->m_log;
3483         int                     iclog_space;
3484         uint                    num_headers;
3485
3486         /*
3487          * Permanent reservations have up to 'cnt'-1 active log operations
3488          * in the log.  A unit in this case is the amount of space for one
3489          * of these log operations.  Normal reservations have a cnt of 1
3490          * and their unit amount is the total amount of space required.
3491          *
3492          * The following lines of code account for non-transaction data
3493          * which occupy space in the on-disk log.
3494          *
3495          * Normal form of a transaction is:
3496          * <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
3497          * and then there are LR hdrs, split-recs and roundoff at end of syncs.
3498          *
3499          * We need to account for all the leadup data and trailer data
3500          * around the transaction data.
3501          * And then we need to account for the worst case in terms of using
3502          * more space.
3503          * The worst case will happen if:
3504          * - the placement of the transaction happens to be such that the
3505          *   roundoff is at its maximum
3506          * - the transaction data is synced before the commit record is synced
3507          *   i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
3508          *   Therefore the commit record is in its own Log Record.
3509          *   This can happen as the commit record is called with its
3510          *   own region to xlog_write().
3511          *   This then means that in the worst case, roundoff can happen for
3512          *   the commit-rec as well.
3513          *   The commit-rec is smaller than padding in this scenario and so it is
3514          *   not added separately.
3515          */
3516
3517         /* for trans header */
3518         unit_bytes += sizeof(xlog_op_header_t);
3519         unit_bytes += sizeof(xfs_trans_header_t);
3520
3521         /* for start-rec */
3522         unit_bytes += sizeof(xlog_op_header_t);
3523
3524         /*
3525          * for LR headers - the space for data in an iclog is the size minus
3526          * the space used for the headers. If we use the iclog size, then we
3527          * undercalculate the number of headers required.
3528          *
3529          * Furthermore - the addition of op headers for split-recs might
3530          * increase the space required enough to require more log and op
3531          * headers, so take that into account too.
3532          *
3533          * IMPORTANT: This reservation makes the assumption that if this
3534          * transaction is the first in an iclog and hence has the LR headers
3535          * accounted to it, then the remaining space in the iclog is
3536          * exclusively for this transaction.  i.e. if the transaction is larger
3537          * than the iclog, it will be the only thing in that iclog.
3538          * Fundamentally, this means we must pass the entire log vector to
3539          * xlog_write to guarantee this.
3540          */
3541         iclog_space = log->l_iclog_size - log->l_iclog_hsize;
3542         num_headers = howmany(unit_bytes, iclog_space);
3543
3544         /* for split-recs - ophdrs added when data split over LRs */
3545         unit_bytes += sizeof(xlog_op_header_t) * num_headers;
3546
3547         /* add extra header reservations if we overrun */
3548         while (!num_headers ||
3549                howmany(unit_bytes, iclog_space) > num_headers) {
3550                 unit_bytes += sizeof(xlog_op_header_t);
3551                 num_headers++;
3552         }
3553         unit_bytes += log->l_iclog_hsize * num_headers;
3554
3555         /* for commit-rec LR header - note: padding will subsume the ophdr */
3556         unit_bytes += log->l_iclog_hsize;
3557
3558         /* for roundoff padding for transaction data and one for commit record */
3559         if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1) {
3560                 /* log su roundoff */
3561                 unit_bytes += 2 * mp->m_sb.sb_logsunit;
3562         } else {
3563                 /* BB roundoff */
3564                 unit_bytes += 2 * BBSIZE;
3565         }
3566
3567         return unit_bytes;
3568 }
3569
3570 /*
3571  * Allocate and initialise a new log ticket.
3572  */
3573 struct xlog_ticket *
3574 xlog_ticket_alloc(
3575         struct xlog             *log,
3576         int                     unit_bytes,
3577         int                     cnt,
3578         char                    client,
3579         bool                    permanent,
3580         xfs_km_flags_t          alloc_flags)
3581 {
3582         struct xlog_ticket      *tic;
3583         int                     unit_res;
3584
3585         tic = kmem_zone_zalloc(xfs_log_ticket_zone, alloc_flags);
3586         if (!tic)
3587                 return NULL;
3588
3589         unit_res = xfs_log_calc_unit_res(log->l_mp, unit_bytes);
3590
3591         atomic_set(&tic->t_ref, 1);
3592         tic->t_task             = current;
3593         INIT_LIST_HEAD(&tic->t_queue);
3594         tic->t_unit_res         = unit_res;
3595         tic->t_curr_res         = unit_res;
3596         tic->t_cnt              = cnt;
3597         tic->t_ocnt             = cnt;
3598         tic->t_tid              = prandom_u32();
3599         tic->t_clientid         = client;
3600         tic->t_flags            = XLOG_TIC_INITED;
3601         if (permanent)
3602                 tic->t_flags |= XLOG_TIC_PERM_RESERV;
3603
3604         xlog_tic_reset_res(tic);
3605
3606         return tic;
3607 }
3608
3609
3610 /******************************************************************************
3611  *
3612  *              Log debug routines
3613  *
3614  ******************************************************************************
3615  */
3616 #if defined(DEBUG)
3617 /*
3618  * Make sure that the destination ptr is within the valid data region of
3619  * one of the iclogs.  This uses backup pointers stored in a different
3620  * part of the log in case we trash the log structure.
3621  */
3622 STATIC void
3623 xlog_verify_dest_ptr(
3624         struct xlog     *log,
3625         void            *ptr)
3626 {
3627         int i;
3628         int good_ptr = 0;
3629
3630         for (i = 0; i < log->l_iclog_bufs; i++) {
3631                 if (ptr >= log->l_iclog_bak[i] &&
3632                     ptr <= log->l_iclog_bak[i] + log->l_iclog_size)
3633                         good_ptr++;
3634         }
3635
3636         if (!good_ptr)
3637                 xfs_emerg(log->l_mp, "%s: invalid ptr", __func__);
3638 }
3639
3640 /*
3641  * Check to make sure the grant write head didn't just over lap the tail.  If
3642  * the cycles are the same, we can't be overlapping.  Otherwise, make sure that
3643  * the cycles differ by exactly one and check the byte count.
3644  *
3645  * This check is run unlocked, so can give false positives. Rather than assert
3646  * on failures, use a warn-once flag and a panic tag to allow the admin to
3647  * determine if they want to panic the machine when such an error occurs. For
3648  * debug kernels this will have the same effect as using an assert but, unlinke
3649  * an assert, it can be turned off at runtime.
3650  */
3651 STATIC void
3652 xlog_verify_grant_tail(
3653         struct xlog     *log)
3654 {
3655         int             tail_cycle, tail_blocks;
3656         int             cycle, space;
3657
3658         xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &space);
3659         xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
3660         if (tail_cycle != cycle) {
3661                 if (cycle - 1 != tail_cycle &&
3662                     !(log->l_flags & XLOG_TAIL_WARN)) {
3663                         xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3664                                 "%s: cycle - 1 != tail_cycle", __func__);
3665                         log->l_flags |= XLOG_TAIL_WARN;
3666                 }
3667
3668                 if (space > BBTOB(tail_blocks) &&
3669                     !(log->l_flags & XLOG_TAIL_WARN)) {
3670                         xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3671                                 "%s: space > BBTOB(tail_blocks)", __func__);
3672                         log->l_flags |= XLOG_TAIL_WARN;
3673                 }
3674         }
3675 }
3676
3677 /* check if it will fit */
3678 STATIC void
3679 xlog_verify_tail_lsn(
3680         struct xlog             *log,
3681         struct xlog_in_core     *iclog,
3682         xfs_lsn_t               tail_lsn)
3683 {
3684     int blocks;
3685
3686     if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
3687         blocks =
3688             log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
3689         if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
3690                 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3691     } else {
3692         ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
3693
3694         if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
3695                 xfs_emerg(log->l_mp, "%s: tail wrapped", __func__);
3696
3697         blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
3698         if (blocks < BTOBB(iclog->ic_offset) + 1)
3699                 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3700     }
3701 }       /* xlog_verify_tail_lsn */
3702
3703 /*
3704  * Perform a number of checks on the iclog before writing to disk.
3705  *
3706  * 1. Make sure the iclogs are still circular
3707  * 2. Make sure we have a good magic number
3708  * 3. Make sure we don't have magic numbers in the data
3709  * 4. Check fields of each log operation header for:
3710  *      A. Valid client identifier
3711  *      B. tid ptr value falls in valid ptr space (user space code)
3712  *      C. Length in log record header is correct according to the
3713  *              individual operation headers within record.
3714  * 5. When a bwrite will occur within 5 blocks of the front of the physical
3715  *      log, check the preceding blocks of the physical log to make sure all
3716  *      the cycle numbers agree with the current cycle number.
3717  */
3718 STATIC void
3719 xlog_verify_iclog(
3720         struct xlog             *log,
3721         struct xlog_in_core     *iclog,
3722         int                     count)
3723 {
3724         xlog_op_header_t        *ophead;
3725         xlog_in_core_t          *icptr;
3726         xlog_in_core_2_t        *xhdr;
3727         void                    *base_ptr, *ptr, *p;
3728         ptrdiff_t               field_offset;
3729         uint8_t                 clientid;
3730         int                     len, i, j, k, op_len;
3731         int                     idx;
3732
3733         /* check validity of iclog pointers */
3734         spin_lock(&log->l_icloglock);
3735         icptr = log->l_iclog;
3736         for (i = 0; i < log->l_iclog_bufs; i++, icptr = icptr->ic_next)
3737                 ASSERT(icptr);
3738
3739         if (icptr != log->l_iclog)
3740                 xfs_emerg(log->l_mp, "%s: corrupt iclog ring", __func__);
3741         spin_unlock(&log->l_icloglock);
3742
3743         /* check log magic numbers */
3744         if (iclog->ic_header.h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3745                 xfs_emerg(log->l_mp, "%s: invalid magic num", __func__);
3746
3747         base_ptr = ptr = &iclog->ic_header;
3748         p = &iclog->ic_header;
3749         for (ptr += BBSIZE; ptr < base_ptr + count; ptr += BBSIZE) {
3750                 if (*(__be32 *)ptr == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3751                         xfs_emerg(log->l_mp, "%s: unexpected magic num",
3752                                 __func__);
3753         }
3754
3755         /* check fields */
3756         len = be32_to_cpu(iclog->ic_header.h_num_logops);
3757         base_ptr = ptr = iclog->ic_datap;
3758         ophead = ptr;
3759         xhdr = iclog->ic_data;
3760         for (i = 0; i < len; i++) {
3761                 ophead = ptr;
3762
3763                 /* clientid is only 1 byte */
3764                 p = &ophead->oh_clientid;
3765                 field_offset = p - base_ptr;
3766                 if (field_offset & 0x1ff) {
3767                         clientid = ophead->oh_clientid;
3768                 } else {
3769                         idx = BTOBBT((char *)&ophead->oh_clientid - iclog->ic_datap);
3770                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3771                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3772                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3773                                 clientid = xlog_get_client_id(
3774                                         xhdr[j].hic_xheader.xh_cycle_data[k]);
3775                         } else {
3776                                 clientid = xlog_get_client_id(
3777                                         iclog->ic_header.h_cycle_data[idx]);
3778                         }
3779                 }
3780                 if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
3781                         xfs_warn(log->l_mp,
3782                                 "%s: invalid clientid %d op "PTR_FMT" offset 0x%lx",
3783                                 __func__, clientid, ophead,
3784                                 (unsigned long)field_offset);
3785
3786                 /* check length */
3787                 p = &ophead->oh_len;
3788                 field_offset = p - base_ptr;
3789                 if (field_offset & 0x1ff) {
3790                         op_len = be32_to_cpu(ophead->oh_len);
3791                 } else {
3792                         idx = BTOBBT((uintptr_t)&ophead->oh_len -
3793                                     (uintptr_t)iclog->ic_datap);
3794                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3795                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3796                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3797                                 op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
3798                         } else {
3799                                 op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
3800                         }
3801                 }
3802                 ptr += sizeof(xlog_op_header_t) + op_len;
3803         }
3804 }       /* xlog_verify_iclog */
3805 #endif
3806
3807 /*
3808  * Mark all iclogs IOERROR. l_icloglock is held by the caller.
3809  */
3810 STATIC int
3811 xlog_state_ioerror(
3812         struct xlog     *log)
3813 {
3814         xlog_in_core_t  *iclog, *ic;
3815
3816         iclog = log->l_iclog;
3817         if (! (iclog->ic_state & XLOG_STATE_IOERROR)) {
3818                 /*
3819                  * Mark all the incore logs IOERROR.
3820                  * From now on, no log flushes will result.
3821                  */
3822                 ic = iclog;
3823                 do {
3824                         ic->ic_state = XLOG_STATE_IOERROR;
3825                         ic = ic->ic_next;
3826                 } while (ic != iclog);
3827                 return 0;
3828         }
3829         /*
3830          * Return non-zero, if state transition has already happened.
3831          */
3832         return 1;
3833 }
3834
3835 /*
3836  * This is called from xfs_force_shutdown, when we're forcibly
3837  * shutting down the filesystem, typically because of an IO error.
3838  * Our main objectives here are to make sure that:
3839  *      a. if !logerror, flush the logs to disk. Anything modified
3840  *         after this is ignored.
3841  *      b. the filesystem gets marked 'SHUTDOWN' for all interested
3842  *         parties to find out, 'atomically'.
3843  *      c. those who're sleeping on log reservations, pinned objects and
3844  *          other resources get woken up, and be told the bad news.
3845  *      d. nothing new gets queued up after (b) and (c) are done.
3846  *
3847  * Note: for the !logerror case we need to flush the regions held in memory out
3848  * to disk first. This needs to be done before the log is marked as shutdown,
3849  * otherwise the iclog writes will fail.
3850  */
3851 int
3852 xfs_log_force_umount(
3853         struct xfs_mount        *mp,
3854         int                     logerror)
3855 {
3856         struct xlog     *log;
3857         int             retval;
3858
3859         log = mp->m_log;
3860
3861         /*
3862          * If this happens during log recovery, don't worry about
3863          * locking; the log isn't open for business yet.
3864          */
3865         if (!log ||
3866             log->l_flags & XLOG_ACTIVE_RECOVERY) {
3867                 mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3868                 if (mp->m_sb_bp)
3869                         mp->m_sb_bp->b_flags |= XBF_DONE;
3870                 return 0;
3871         }
3872
3873         /*
3874          * Somebody could've already done the hard work for us.
3875          * No need to get locks for this.
3876          */
3877         if (logerror && log->l_iclog->ic_state & XLOG_STATE_IOERROR) {
3878                 ASSERT(XLOG_FORCED_SHUTDOWN(log));
3879                 return 1;
3880         }
3881
3882         /*
3883          * Flush all the completed transactions to disk before marking the log
3884          * being shut down. We need to do it in this order to ensure that
3885          * completed operations are safely on disk before we shut down, and that
3886          * we don't have to issue any buffer IO after the shutdown flags are set
3887          * to guarantee this.
3888          */
3889         if (!logerror)
3890                 xfs_log_force(mp, XFS_LOG_SYNC);
3891
3892         /*
3893          * mark the filesystem and the as in a shutdown state and wake
3894          * everybody up to tell them the bad news.
3895          */
3896         spin_lock(&log->l_icloglock);
3897         mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3898         if (mp->m_sb_bp)
3899                 mp->m_sb_bp->b_flags |= XBF_DONE;
3900
3901         /*
3902          * Mark the log and the iclogs with IO error flags to prevent any
3903          * further log IO from being issued or completed.
3904          */
3905         log->l_flags |= XLOG_IO_ERROR;
3906         retval = xlog_state_ioerror(log);
3907         spin_unlock(&log->l_icloglock);
3908
3909         /*
3910          * We don't want anybody waiting for log reservations after this. That
3911          * means we have to wake up everybody queued up on reserveq as well as
3912          * writeq.  In addition, we make sure in xlog_{re}grant_log_space that
3913          * we don't enqueue anything once the SHUTDOWN flag is set, and this
3914          * action is protected by the grant locks.
3915          */
3916         xlog_grant_head_wake_all(&log->l_reserve_head);
3917         xlog_grant_head_wake_all(&log->l_write_head);
3918
3919         /*
3920          * Wake up everybody waiting on xfs_log_force. Wake the CIL push first
3921          * as if the log writes were completed. The abort handling in the log
3922          * item committed callback functions will do this again under lock to
3923          * avoid races.
3924          */
3925         wake_up_all(&log->l_cilp->xc_commit_wait);
3926         xlog_state_do_callback(log, true, NULL);
3927
3928 #ifdef XFSERRORDEBUG
3929         {
3930                 xlog_in_core_t  *iclog;
3931
3932                 spin_lock(&log->l_icloglock);
3933                 iclog = log->l_iclog;
3934                 do {
3935                         ASSERT(iclog->ic_callback == 0);
3936                         iclog = iclog->ic_next;
3937                 } while (iclog != log->l_iclog);
3938                 spin_unlock(&log->l_icloglock);
3939         }
3940 #endif
3941         /* return non-zero if log IOERROR transition had already happened */
3942         return retval;
3943 }
3944
3945 STATIC int
3946 xlog_iclogs_empty(
3947         struct xlog     *log)
3948 {
3949         xlog_in_core_t  *iclog;
3950
3951         iclog = log->l_iclog;
3952         do {
3953                 /* endianness does not matter here, zero is zero in
3954                  * any language.
3955                  */
3956                 if (iclog->ic_header.h_num_logops)
3957                         return 0;
3958                 iclog = iclog->ic_next;
3959         } while (iclog != log->l_iclog);
3960         return 1;
3961 }
3962
3963 /*
3964  * Verify that an LSN stamped into a piece of metadata is valid. This is
3965  * intended for use in read verifiers on v5 superblocks.
3966  */
3967 bool
3968 xfs_log_check_lsn(
3969         struct xfs_mount        *mp,
3970         xfs_lsn_t               lsn)
3971 {
3972         struct xlog             *log = mp->m_log;
3973         bool                    valid;
3974
3975         /*
3976          * norecovery mode skips mount-time log processing and unconditionally
3977          * resets the in-core LSN. We can't validate in this mode, but
3978          * modifications are not allowed anyways so just return true.
3979          */
3980         if (mp->m_flags & XFS_MOUNT_NORECOVERY)
3981                 return true;
3982
3983         /*
3984          * Some metadata LSNs are initialized to NULL (e.g., the agfl). This is
3985          * handled by recovery and thus safe to ignore here.
3986          */
3987         if (lsn == NULLCOMMITLSN)
3988                 return true;
3989
3990         valid = xlog_valid_lsn(mp->m_log, lsn);
3991
3992         /* warn the user about what's gone wrong before verifier failure */
3993         if (!valid) {
3994                 spin_lock(&log->l_icloglock);
3995                 xfs_warn(mp,
3996 "Corruption warning: Metadata has LSN (%d:%d) ahead of current LSN (%d:%d). "
3997 "Please unmount and run xfs_repair (>= v4.3) to resolve.",
3998                          CYCLE_LSN(lsn), BLOCK_LSN(lsn),
3999                          log->l_curr_cycle, log->l_curr_block);
4000                 spin_unlock(&log->l_icloglock);
4001         }
4002
4003         return valid;
4004 }
4005
4006 bool
4007 xfs_log_in_recovery(
4008         struct xfs_mount        *mp)
4009 {
4010         struct xlog             *log = mp->m_log;
4011
4012         return log->l_flags & XLOG_ACTIVE_RECOVERY;
4013 }