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