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, 0);
 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  * Push on the buffer cache code if we ever use more than 75% of the on-disk
1479  * log space.  This code pushes on the lsn which would supposedly free up
1480  * the 25% which we want to leave free.  We may need to adopt a policy which
1481  * pushes on an lsn which is further along in the log once we reach the high
1482  * water mark.  In this manner, we would be creating a low water mark.
1483  */
1484 STATIC void
1485 xlog_grant_push_ail(
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;
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         /*
1532          * Get the transaction layer to kick the dirty buffers out to
1533          * disk asynchronously. No point in trying to do this if
1534          * the filesystem is shutting down.
1535          */
1536         if (!XLOG_FORCED_SHUTDOWN(log))
1537                 xfs_ail_push(log->l_ailp, threshold_lsn);
1538 }
1539
1540 /*
1541  * Stamp cycle number in every block
1542  */
1543 STATIC void
1544 xlog_pack_data(
1545         struct xlog             *log,
1546         struct xlog_in_core     *iclog,
1547         int                     roundoff)
1548 {
1549         int                     i, j, k;
1550         int                     size = iclog->ic_offset + roundoff;
1551         __be32                  cycle_lsn;
1552         char                    *dp;
1553
1554         cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn);
1555
1556         dp = iclog->ic_datap;
1557         for (i = 0; i < BTOBB(size); i++) {
1558                 if (i >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE))
1559                         break;
1560                 iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp;
1561                 *(__be32 *)dp = cycle_lsn;
1562                 dp += BBSIZE;
1563         }
1564
1565         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1566                 xlog_in_core_2_t *xhdr = iclog->ic_data;
1567
1568                 for ( ; i < BTOBB(size); i++) {
1569                         j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1570                         k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1571                         xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp;
1572                         *(__be32 *)dp = cycle_lsn;
1573                         dp += BBSIZE;
1574                 }
1575
1576                 for (i = 1; i < log->l_iclog_heads; i++)
1577                         xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
1578         }
1579 }
1580
1581 /*
1582  * Calculate the checksum for a log buffer.
1583  *
1584  * This is a little more complicated than it should be because the various
1585  * headers and the actual data are non-contiguous.
1586  */
1587 __le32
1588 xlog_cksum(
1589         struct xlog             *log,
1590         struct xlog_rec_header  *rhead,
1591         char                    *dp,
1592         int                     size)
1593 {
1594         uint32_t                crc;
1595
1596         /* first generate the crc for the record header ... */
1597         crc = xfs_start_cksum_update((char *)rhead,
1598                               sizeof(struct xlog_rec_header),
1599                               offsetof(struct xlog_rec_header, h_crc));
1600
1601         /* ... then for additional cycle data for v2 logs ... */
1602         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1603                 union xlog_in_core2 *xhdr = (union xlog_in_core2 *)rhead;
1604                 int             i;
1605                 int             xheads;
1606
1607                 xheads = size / XLOG_HEADER_CYCLE_SIZE;
1608                 if (size % XLOG_HEADER_CYCLE_SIZE)
1609                         xheads++;
1610
1611                 for (i = 1; i < xheads; i++) {
1612                         crc = crc32c(crc, &xhdr[i].hic_xheader,
1613                                      sizeof(struct xlog_rec_ext_header));
1614                 }
1615         }
1616
1617         /* ... and finally for the payload */
1618         crc = crc32c(crc, dp, size);
1619
1620         return xfs_end_cksum(crc);
1621 }
1622
1623 static void
1624 xlog_bio_end_io(
1625         struct bio              *bio)
1626 {
1627         struct xlog_in_core     *iclog = bio->bi_private;
1628
1629         queue_work(iclog->ic_log->l_ioend_workqueue,
1630                    &iclog->ic_end_io_work);
1631 }
1632
1633 static int
1634 xlog_map_iclog_data(
1635         struct bio              *bio,
1636         void                    *data,
1637         size_t                  count)
1638 {
1639         do {
1640                 struct page     *page = kmem_to_page(data);
1641                 unsigned int    off = offset_in_page(data);
1642                 size_t          len = min_t(size_t, count, PAGE_SIZE - off);
1643
1644                 if (bio_add_page(bio, page, len, off) != len)
1645                         return -EIO;
1646
1647                 data += len;
1648                 count -= len;
1649         } while (count);
1650
1651         return 0;
1652 }
1653
1654 STATIC void
1655 xlog_write_iclog(
1656         struct xlog             *log,
1657         struct xlog_in_core     *iclog,
1658         uint64_t                bno,
1659         unsigned int            count,
1660         bool                    need_flush)
1661 {
1662         ASSERT(bno < log->l_logBBsize);
1663
1664         /*
1665          * We lock the iclogbufs here so that we can serialise against I/O
1666          * completion during unmount.  We might be processing a shutdown
1667          * triggered during unmount, and that can occur asynchronously to the
1668          * unmount thread, and hence we need to ensure that completes before
1669          * tearing down the iclogbufs.  Hence we need to hold the buffer lock
1670          * across the log IO to archieve that.
1671          */
1672         down(&iclog->ic_sema);
1673         if (unlikely(iclog->ic_state == XLOG_STATE_IOERROR)) {
1674                 /*
1675                  * It would seem logical to return EIO here, but we rely on
1676                  * the log state machine to propagate I/O errors instead of
1677                  * doing it here.  We kick of the state machine and unlock
1678                  * the buffer manually, the code needs to be kept in sync
1679                  * with the I/O completion path.
1680                  */
1681                 xlog_state_done_syncing(iclog);
1682                 up(&iclog->ic_sema);
1683                 return;
1684         }
1685
1686         bio_init(&iclog->ic_bio, iclog->ic_bvec, howmany(count, PAGE_SIZE));
1687         bio_set_dev(&iclog->ic_bio, log->l_targ->bt_bdev);
1688         iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart + bno;
1689         iclog->ic_bio.bi_end_io = xlog_bio_end_io;
1690         iclog->ic_bio.bi_private = iclog;
1691
1692         /*
1693          * We use REQ_SYNC | REQ_IDLE here to tell the block layer the are more
1694          * IOs coming immediately after this one. This prevents the block layer
1695          * writeback throttle from throttling log writes behind background
1696          * metadata writeback and causing priority inversions.
1697          */
1698         iclog->ic_bio.bi_opf = REQ_OP_WRITE | REQ_META | REQ_SYNC |
1699                                 REQ_IDLE | REQ_FUA;
1700         if (need_flush)
1701                 iclog->ic_bio.bi_opf |= REQ_PREFLUSH;
1702
1703         if (xlog_map_iclog_data(&iclog->ic_bio, iclog->ic_data, count)) {
1704                 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
1705                 return;
1706         }
1707         if (is_vmalloc_addr(iclog->ic_data))
1708                 flush_kernel_vmap_range(iclog->ic_data, count);
1709
1710         /*
1711          * If this log buffer would straddle the end of the log we will have
1712          * to split it up into two bios, so that we can continue at the start.
1713          */
1714         if (bno + BTOBB(count) > log->l_logBBsize) {
1715                 struct bio *split;
1716
1717                 split = bio_split(&iclog->ic_bio, log->l_logBBsize - bno,
1718                                   GFP_NOIO, &fs_bio_set);
1719                 bio_chain(split, &iclog->ic_bio);
1720                 submit_bio(split);
1721
1722                 /* restart at logical offset zero for the remainder */
1723                 iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart;
1724         }
1725
1726         submit_bio(&iclog->ic_bio);
1727 }
1728
1729 /*
1730  * We need to bump cycle number for the part of the iclog that is
1731  * written to the start of the log. Watch out for the header magic
1732  * number case, though.
1733  */
1734 static void
1735 xlog_split_iclog(
1736         struct xlog             *log,
1737         void                    *data,
1738         uint64_t                bno,
1739         unsigned int            count)
1740 {
1741         unsigned int            split_offset = BBTOB(log->l_logBBsize - bno);
1742         unsigned int            i;
1743
1744         for (i = split_offset; i < count; i += BBSIZE) {
1745                 uint32_t cycle = get_unaligned_be32(data + i);
1746
1747                 if (++cycle == XLOG_HEADER_MAGIC_NUM)
1748                         cycle++;
1749                 put_unaligned_be32(cycle, data + i);
1750         }
1751 }
1752
1753 static int
1754 xlog_calc_iclog_size(
1755         struct xlog             *log,
1756         struct xlog_in_core     *iclog,
1757         uint32_t                *roundoff)
1758 {
1759         uint32_t                count_init, count;
1760         bool                    use_lsunit;
1761
1762         use_lsunit = xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
1763                         log->l_mp->m_sb.sb_logsunit > 1;
1764
1765         /* Add for LR header */
1766         count_init = log->l_iclog_hsize + iclog->ic_offset;
1767
1768         /* Round out the log write size */
1769         if (use_lsunit) {
1770                 /* we have a v2 stripe unit to use */
1771                 count = XLOG_LSUNITTOB(log, XLOG_BTOLSUNIT(log, count_init));
1772         } else {
1773                 count = BBTOB(BTOBB(count_init));
1774         }
1775
1776         ASSERT(count >= count_init);
1777         *roundoff = count - count_init;
1778
1779         if (use_lsunit)
1780                 ASSERT(*roundoff < log->l_mp->m_sb.sb_logsunit);
1781         else
1782                 ASSERT(*roundoff < BBTOB(1));
1783         return count;
1784 }
1785
1786 /*
1787  * Flush out the in-core log (iclog) to the on-disk log in an asynchronous
1788  * fashion.  Previously, we should have moved the current iclog
1789  * ptr in the log to point to the next available iclog.  This allows further
1790  * write to continue while this code syncs out an iclog ready to go.
1791  * Before an in-core log can be written out, the data section must be scanned
1792  * to save away the 1st word of each BBSIZE block into the header.  We replace
1793  * it with the current cycle count.  Each BBSIZE block is tagged with the
1794  * cycle count because there in an implicit assumption that drives will
1795  * guarantee that entire 512 byte blocks get written at once.  In other words,
1796  * we can't have part of a 512 byte block written and part not written.  By
1797  * tagging each block, we will know which blocks are valid when recovering
1798  * after an unclean shutdown.
1799  *
1800  * This routine is single threaded on the iclog.  No other thread can be in
1801  * this routine with the same iclog.  Changing contents of iclog can there-
1802  * fore be done without grabbing the state machine lock.  Updating the global
1803  * log will require grabbing the lock though.
1804  *
1805  * The entire log manager uses a logical block numbering scheme.  Only
1806  * xlog_write_iclog knows about the fact that the log may not start with
1807  * block zero on a given device.
1808  */
1809 STATIC void
1810 xlog_sync(
1811         struct xlog             *log,
1812         struct xlog_in_core     *iclog)
1813 {
1814         unsigned int            count;          /* byte count of bwrite */
1815         unsigned int            roundoff;       /* roundoff to BB or stripe */
1816         uint64_t                bno;
1817         unsigned int            size;
1818         bool                    need_flush = true, split = false;
1819
1820         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
1821
1822         count = xlog_calc_iclog_size(log, iclog, &roundoff);
1823
1824         /* move grant heads by roundoff in sync */
1825         xlog_grant_add_space(log, &log->l_reserve_head.grant, roundoff);
1826         xlog_grant_add_space(log, &log->l_write_head.grant, roundoff);
1827
1828         /* put cycle number in every block */
1829         xlog_pack_data(log, iclog, roundoff);
1830
1831         /* real byte length */
1832         size = iclog->ic_offset;
1833         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb))
1834                 size += roundoff;
1835         iclog->ic_header.h_len = cpu_to_be32(size);
1836
1837         XFS_STATS_INC(log->l_mp, xs_log_writes);
1838         XFS_STATS_ADD(log->l_mp, xs_log_blocks, BTOBB(count));
1839
1840         bno = BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn));
1841
1842         /* Do we need to split this write into 2 parts? */
1843         if (bno + BTOBB(count) > log->l_logBBsize) {
1844                 xlog_split_iclog(log, &iclog->ic_header, bno, count);
1845                 split = true;
1846         }
1847
1848         /* calculcate the checksum */
1849         iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header,
1850                                             iclog->ic_datap, size);
1851         /*
1852          * Intentionally corrupt the log record CRC based on the error injection
1853          * frequency, if defined. This facilitates testing log recovery in the
1854          * event of torn writes. Hence, set the IOABORT state to abort the log
1855          * write on I/O completion and shutdown the fs. The subsequent mount
1856          * detects the bad CRC and attempts to recover.
1857          */
1858 #ifdef DEBUG
1859         if (XFS_TEST_ERROR(false, log->l_mp, XFS_ERRTAG_LOG_BAD_CRC)) {
1860                 iclog->ic_header.h_crc &= cpu_to_le32(0xAAAAAAAA);
1861                 iclog->ic_fail_crc = true;
1862                 xfs_warn(log->l_mp,
1863         "Intentionally corrupted log record at LSN 0x%llx. Shutdown imminent.",
1864                          be64_to_cpu(iclog->ic_header.h_lsn));
1865         }
1866 #endif
1867
1868         /*
1869          * Flush the data device before flushing the log to make sure all meta
1870          * data written back from the AIL actually made it to disk before
1871          * stamping the new log tail LSN into the log buffer.  For an external
1872          * log we need to issue the flush explicitly, and unfortunately
1873          * synchronously here; for an internal log we can simply use the block
1874          * layer state machine for preflushes.
1875          */
1876         if (log->l_targ != log->l_mp->m_ddev_targp || split) {
1877                 xfs_blkdev_issue_flush(log->l_mp->m_ddev_targp);
1878                 need_flush = false;
1879         }
1880
1881         xlog_verify_iclog(log, iclog, count);
1882         xlog_write_iclog(log, iclog, bno, count, need_flush);
1883 }
1884
1885 /*
1886  * Deallocate a log structure
1887  */
1888 STATIC void
1889 xlog_dealloc_log(
1890         struct xlog     *log)
1891 {
1892         xlog_in_core_t  *iclog, *next_iclog;
1893         int             i;
1894
1895         xlog_cil_destroy(log);
1896
1897         /*
1898          * Cycle all the iclogbuf locks to make sure all log IO completion
1899          * is done before we tear down these buffers.
1900          */
1901         iclog = log->l_iclog;
1902         for (i = 0; i < log->l_iclog_bufs; i++) {
1903                 down(&iclog->ic_sema);
1904                 up(&iclog->ic_sema);
1905                 iclog = iclog->ic_next;
1906         }
1907
1908         iclog = log->l_iclog;
1909         for (i = 0; i < log->l_iclog_bufs; i++) {
1910                 next_iclog = iclog->ic_next;
1911                 kmem_free(iclog->ic_data);
1912                 kmem_free(iclog);
1913                 iclog = next_iclog;
1914         }
1915
1916         log->l_mp->m_log = NULL;
1917         destroy_workqueue(log->l_ioend_workqueue);
1918         kmem_free(log);
1919 }
1920
1921 /*
1922  * Update counters atomically now that memcpy is done.
1923  */
1924 static inline void
1925 xlog_state_finish_copy(
1926         struct xlog             *log,
1927         struct xlog_in_core     *iclog,
1928         int                     record_cnt,
1929         int                     copy_bytes)
1930 {
1931         lockdep_assert_held(&log->l_icloglock);
1932
1933         be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
1934         iclog->ic_offset += copy_bytes;
1935 }
1936
1937 /*
1938  * print out info relating to regions written which consume
1939  * the reservation
1940  */
1941 void
1942 xlog_print_tic_res(
1943         struct xfs_mount        *mp,
1944         struct xlog_ticket      *ticket)
1945 {
1946         uint i;
1947         uint ophdr_spc = ticket->t_res_num_ophdrs * (uint)sizeof(xlog_op_header_t);
1948
1949         /* match with XLOG_REG_TYPE_* in xfs_log.h */
1950 #define REG_TYPE_STR(type, str) [XLOG_REG_TYPE_##type] = str
1951         static char *res_type_str[] = {
1952             REG_TYPE_STR(BFORMAT, "bformat"),
1953             REG_TYPE_STR(BCHUNK, "bchunk"),
1954             REG_TYPE_STR(EFI_FORMAT, "efi_format"),
1955             REG_TYPE_STR(EFD_FORMAT, "efd_format"),
1956             REG_TYPE_STR(IFORMAT, "iformat"),
1957             REG_TYPE_STR(ICORE, "icore"),
1958             REG_TYPE_STR(IEXT, "iext"),
1959             REG_TYPE_STR(IBROOT, "ibroot"),
1960             REG_TYPE_STR(ILOCAL, "ilocal"),
1961             REG_TYPE_STR(IATTR_EXT, "iattr_ext"),
1962             REG_TYPE_STR(IATTR_BROOT, "iattr_broot"),
1963             REG_TYPE_STR(IATTR_LOCAL, "iattr_local"),
1964             REG_TYPE_STR(QFORMAT, "qformat"),
1965             REG_TYPE_STR(DQUOT, "dquot"),
1966             REG_TYPE_STR(QUOTAOFF, "quotaoff"),
1967             REG_TYPE_STR(LRHEADER, "LR header"),
1968             REG_TYPE_STR(UNMOUNT, "unmount"),
1969             REG_TYPE_STR(COMMIT, "commit"),
1970             REG_TYPE_STR(TRANSHDR, "trans header"),
1971             REG_TYPE_STR(ICREATE, "inode create"),
1972             REG_TYPE_STR(RUI_FORMAT, "rui_format"),
1973             REG_TYPE_STR(RUD_FORMAT, "rud_format"),
1974             REG_TYPE_STR(CUI_FORMAT, "cui_format"),
1975             REG_TYPE_STR(CUD_FORMAT, "cud_format"),
1976             REG_TYPE_STR(BUI_FORMAT, "bui_format"),
1977             REG_TYPE_STR(BUD_FORMAT, "bud_format"),
1978         };
1979         BUILD_BUG_ON(ARRAY_SIZE(res_type_str) != XLOG_REG_TYPE_MAX + 1);
1980 #undef REG_TYPE_STR
1981
1982         xfs_warn(mp, "ticket reservation summary:");
1983         xfs_warn(mp, "  unit res    = %d bytes",
1984                  ticket->t_unit_res);
1985         xfs_warn(mp, "  current res = %d bytes",
1986                  ticket->t_curr_res);
1987         xfs_warn(mp, "  total reg   = %u bytes (o/flow = %u bytes)",
1988                  ticket->t_res_arr_sum, ticket->t_res_o_flow);
1989         xfs_warn(mp, "  ophdrs      = %u (ophdr space = %u bytes)",
1990                  ticket->t_res_num_ophdrs, ophdr_spc);
1991         xfs_warn(mp, "  ophdr + reg = %u bytes",
1992                  ticket->t_res_arr_sum + ticket->t_res_o_flow + ophdr_spc);
1993         xfs_warn(mp, "  num regions = %u",
1994                  ticket->t_res_num);
1995
1996         for (i = 0; i < ticket->t_res_num; i++) {
1997                 uint r_type = ticket->t_res_arr[i].r_type;
1998                 xfs_warn(mp, "region[%u]: %s - %u bytes", i,
1999                             ((r_type <= 0 || r_type > XLOG_REG_TYPE_MAX) ?
2000                             "bad-rtype" : res_type_str[r_type]),
2001                             ticket->t_res_arr[i].r_len);
2002         }
2003 }
2004
2005 /*
2006  * Print a summary of the transaction.
2007  */
2008 void
2009 xlog_print_trans(
2010         struct xfs_trans        *tp)
2011 {
2012         struct xfs_mount        *mp = tp->t_mountp;
2013         struct xfs_log_item     *lip;
2014
2015         /* dump core transaction and ticket info */
2016         xfs_warn(mp, "transaction summary:");
2017         xfs_warn(mp, "  log res   = %d", tp->t_log_res);
2018         xfs_warn(mp, "  log count = %d", tp->t_log_count);
2019         xfs_warn(mp, "  flags     = 0x%x", tp->t_flags);
2020
2021         xlog_print_tic_res(mp, tp->t_ticket);
2022
2023         /* dump each log item */
2024         list_for_each_entry(lip, &tp->t_items, li_trans) {
2025                 struct xfs_log_vec      *lv = lip->li_lv;
2026                 struct xfs_log_iovec    *vec;
2027                 int                     i;
2028
2029                 xfs_warn(mp, "log item: ");
2030                 xfs_warn(mp, "  type    = 0x%x", lip->li_type);
2031                 xfs_warn(mp, "  flags   = 0x%lx", lip->li_flags);
2032                 if (!lv)
2033                         continue;
2034                 xfs_warn(mp, "  niovecs = %d", lv->lv_niovecs);
2035                 xfs_warn(mp, "  size    = %d", lv->lv_size);
2036                 xfs_warn(mp, "  bytes   = %d", lv->lv_bytes);
2037                 xfs_warn(mp, "  buf len = %d", lv->lv_buf_len);
2038
2039                 /* dump each iovec for the log item */
2040                 vec = lv->lv_iovecp;
2041                 for (i = 0; i < lv->lv_niovecs; i++) {
2042                         int dumplen = min(vec->i_len, 32);
2043
2044                         xfs_warn(mp, "  iovec[%d]", i);
2045                         xfs_warn(mp, "    type  = 0x%x", vec->i_type);
2046                         xfs_warn(mp, "    len   = %d", vec->i_len);
2047                         xfs_warn(mp, "    first %d bytes of iovec[%d]:", dumplen, i);
2048                         xfs_hex_dump(vec->i_addr, dumplen);
2049
2050                         vec++;
2051                 }
2052         }
2053 }
2054
2055 /*
2056  * Calculate the potential space needed by the log vector.  We may need a start
2057  * record, and each region gets its own struct xlog_op_header and may need to be
2058  * double word aligned.
2059  */
2060 static int
2061 xlog_write_calc_vec_length(
2062         struct xlog_ticket      *ticket,
2063         struct xfs_log_vec      *log_vector,
2064         bool                    need_start_rec)
2065 {
2066         struct xfs_log_vec      *lv;
2067         int                     headers = need_start_rec ? 1 : 0;
2068         int                     len = 0;
2069         int                     i;
2070
2071         for (lv = log_vector; lv; lv = lv->lv_next) {
2072                 /* we don't write ordered log vectors */
2073                 if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED)
2074                         continue;
2075
2076                 headers += lv->lv_niovecs;
2077
2078                 for (i = 0; i < lv->lv_niovecs; i++) {
2079                         struct xfs_log_iovec    *vecp = &lv->lv_iovecp[i];
2080
2081                         len += vecp->i_len;
2082                         xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type);
2083                 }
2084         }
2085
2086         ticket->t_res_num_ophdrs += headers;
2087         len += headers * sizeof(struct xlog_op_header);
2088
2089         return len;
2090 }
2091
2092 static void
2093 xlog_write_start_rec(
2094         struct xlog_op_header   *ophdr,
2095         struct xlog_ticket      *ticket)
2096 {
2097         ophdr->oh_tid   = cpu_to_be32(ticket->t_tid);
2098         ophdr->oh_clientid = ticket->t_clientid;
2099         ophdr->oh_len = 0;
2100         ophdr->oh_flags = XLOG_START_TRANS;
2101         ophdr->oh_res2 = 0;
2102 }
2103
2104 static xlog_op_header_t *
2105 xlog_write_setup_ophdr(
2106         struct xlog             *log,
2107         struct xlog_op_header   *ophdr,
2108         struct xlog_ticket      *ticket,
2109         uint                    flags)
2110 {
2111         ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2112         ophdr->oh_clientid = ticket->t_clientid;
2113         ophdr->oh_res2 = 0;
2114
2115         /* are we copying a commit or unmount record? */
2116         ophdr->oh_flags = flags;
2117
2118         /*
2119          * We've seen logs corrupted with bad transaction client ids.  This
2120          * makes sure that XFS doesn't generate them on.  Turn this into an EIO
2121          * and shut down the filesystem.
2122          */
2123         switch (ophdr->oh_clientid)  {
2124         case XFS_TRANSACTION:
2125         case XFS_VOLUME:
2126         case XFS_LOG:
2127                 break;
2128         default:
2129                 xfs_warn(log->l_mp,
2130                         "Bad XFS transaction clientid 0x%x in ticket "PTR_FMT,
2131                         ophdr->oh_clientid, ticket);
2132                 return NULL;
2133         }
2134
2135         return ophdr;
2136 }
2137
2138 /*
2139  * Set up the parameters of the region copy into the log. This has
2140  * to handle region write split across multiple log buffers - this
2141  * state is kept external to this function so that this code can
2142  * be written in an obvious, self documenting manner.
2143  */
2144 static int
2145 xlog_write_setup_copy(
2146         struct xlog_ticket      *ticket,
2147         struct xlog_op_header   *ophdr,
2148         int                     space_available,
2149         int                     space_required,
2150         int                     *copy_off,
2151         int                     *copy_len,
2152         int                     *last_was_partial_copy,
2153         int                     *bytes_consumed)
2154 {
2155         int                     still_to_copy;
2156
2157         still_to_copy = space_required - *bytes_consumed;
2158         *copy_off = *bytes_consumed;
2159
2160         if (still_to_copy <= space_available) {
2161                 /* write of region completes here */
2162                 *copy_len = still_to_copy;
2163                 ophdr->oh_len = cpu_to_be32(*copy_len);
2164                 if (*last_was_partial_copy)
2165                         ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
2166                 *last_was_partial_copy = 0;
2167                 *bytes_consumed = 0;
2168                 return 0;
2169         }
2170
2171         /* partial write of region, needs extra log op header reservation */
2172         *copy_len = space_available;
2173         ophdr->oh_len = cpu_to_be32(*copy_len);
2174         ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
2175         if (*last_was_partial_copy)
2176                 ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
2177         *bytes_consumed += *copy_len;
2178         (*last_was_partial_copy)++;
2179
2180         /* account for new log op header */
2181         ticket->t_curr_res -= sizeof(struct xlog_op_header);
2182         ticket->t_res_num_ophdrs++;
2183
2184         return sizeof(struct xlog_op_header);
2185 }
2186
2187 static int
2188 xlog_write_copy_finish(
2189         struct xlog             *log,
2190         struct xlog_in_core     *iclog,
2191         uint                    flags,
2192         int                     *record_cnt,
2193         int                     *data_cnt,
2194         int                     *partial_copy,
2195         int                     *partial_copy_len,
2196         int                     log_offset,
2197         struct xlog_in_core     **commit_iclog)
2198 {
2199         int                     error;
2200
2201         if (*partial_copy) {
2202                 /*
2203                  * This iclog has already been marked WANT_SYNC by
2204                  * xlog_state_get_iclog_space.
2205                  */
2206                 spin_lock(&log->l_icloglock);
2207                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2208                 *record_cnt = 0;
2209                 *data_cnt = 0;
2210                 goto release_iclog;
2211         }
2212
2213         *partial_copy = 0;
2214         *partial_copy_len = 0;
2215
2216         if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
2217                 /* no more space in this iclog - push it. */
2218                 spin_lock(&log->l_icloglock);
2219                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2220                 *record_cnt = 0;
2221                 *data_cnt = 0;
2222
2223                 if (iclog->ic_state == XLOG_STATE_ACTIVE)
2224                         xlog_state_switch_iclogs(log, iclog, 0);
2225                 else
2226                         ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC ||
2227                                iclog->ic_state == XLOG_STATE_IOERROR);
2228                 if (!commit_iclog)
2229                         goto release_iclog;
2230                 spin_unlock(&log->l_icloglock);
2231                 ASSERT(flags & XLOG_COMMIT_TRANS);
2232                 *commit_iclog = iclog;
2233         }
2234
2235         return 0;
2236
2237 release_iclog:
2238         error = xlog_state_release_iclog(log, iclog);
2239         spin_unlock(&log->l_icloglock);
2240         return error;
2241 }
2242
2243 /*
2244  * Write some region out to in-core log
2245  *
2246  * This will be called when writing externally provided regions or when
2247  * writing out a commit record for a given transaction.
2248  *
2249  * General algorithm:
2250  *      1. Find total length of this write.  This may include adding to the
2251  *              lengths passed in.
2252  *      2. Check whether we violate the tickets reservation.
2253  *      3. While writing to this iclog
2254  *          A. Reserve as much space in this iclog as can get
2255  *          B. If this is first write, save away start lsn
2256  *          C. While writing this region:
2257  *              1. If first write of transaction, write start record
2258  *              2. Write log operation header (header per region)
2259  *              3. Find out if we can fit entire region into this iclog
2260  *              4. Potentially, verify destination memcpy ptr
2261  *              5. Memcpy (partial) region
2262  *              6. If partial copy, release iclog; otherwise, continue
2263  *                      copying more regions into current iclog
2264  *      4. Mark want sync bit (in simulation mode)
2265  *      5. Release iclog for potential flush to on-disk log.
2266  *
2267  * ERRORS:
2268  * 1.   Panic if reservation is overrun.  This should never happen since
2269  *      reservation amounts are generated internal to the filesystem.
2270  * NOTES:
2271  * 1. Tickets are single threaded data structures.
2272  * 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
2273  *      syncing routine.  When a single log_write region needs to span
2274  *      multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
2275  *      on all log operation writes which don't contain the end of the
2276  *      region.  The XLOG_END_TRANS bit is used for the in-core log
2277  *      operation which contains the end of the continued log_write region.
2278  * 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
2279  *      we don't really know exactly how much space will be used.  As a result,
2280  *      we don't update ic_offset until the end when we know exactly how many
2281  *      bytes have been written out.
2282  */
2283 int
2284 xlog_write(
2285         struct xlog             *log,
2286         struct xfs_log_vec      *log_vector,
2287         struct xlog_ticket      *ticket,
2288         xfs_lsn_t               *start_lsn,
2289         struct xlog_in_core     **commit_iclog,
2290         uint                    flags,
2291         bool                    need_start_rec)
2292 {
2293         struct xlog_in_core     *iclog = NULL;
2294         struct xfs_log_vec      *lv = log_vector;
2295         struct xfs_log_iovec    *vecp = lv->lv_iovecp;
2296         int                     index = 0;
2297         int                     len;
2298         int                     partial_copy = 0;
2299         int                     partial_copy_len = 0;
2300         int                     contwr = 0;
2301         int                     record_cnt = 0;
2302         int                     data_cnt = 0;
2303         int                     error = 0;
2304
2305         /*
2306          * If this is a commit or unmount transaction, we don't need a start
2307          * record to be written.  We do, however, have to account for the
2308          * commit or unmount header that gets written. Hence we always have
2309          * to account for an extra xlog_op_header here.
2310          */
2311         ticket->t_curr_res -= sizeof(struct xlog_op_header);
2312         if (ticket->t_curr_res < 0) {
2313                 xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
2314                      "ctx ticket reservation ran out. Need to up reservation");
2315                 xlog_print_tic_res(log->l_mp, ticket);
2316                 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
2317         }
2318
2319         len = xlog_write_calc_vec_length(ticket, log_vector, need_start_rec);
2320         *start_lsn = 0;
2321         while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2322                 void            *ptr;
2323                 int             log_offset;
2324
2325                 error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
2326                                                    &contwr, &log_offset);
2327                 if (error)
2328                         return error;
2329
2330                 ASSERT(log_offset <= iclog->ic_size - 1);
2331                 ptr = iclog->ic_datap + log_offset;
2332
2333                 /* start_lsn is the first lsn written to. That's all we need. */
2334                 if (!*start_lsn)
2335                         *start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2336
2337                 /*
2338                  * This loop writes out as many regions as can fit in the amount
2339                  * of space which was allocated by xlog_state_get_iclog_space().
2340                  */
2341                 while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2342                         struct xfs_log_iovec    *reg;
2343                         struct xlog_op_header   *ophdr;
2344                         int                     copy_len;
2345                         int                     copy_off;
2346                         bool                    ordered = false;
2347
2348                         /* ordered log vectors have no regions to write */
2349                         if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) {
2350                                 ASSERT(lv->lv_niovecs == 0);
2351                                 ordered = true;
2352                                 goto next_lv;
2353                         }
2354
2355                         reg = &vecp[index];
2356                         ASSERT(reg->i_len % sizeof(int32_t) == 0);
2357                         ASSERT((unsigned long)ptr % sizeof(int32_t) == 0);
2358
2359                         /*
2360                          * Before we start formatting log vectors, we need to
2361                          * write a start record. Only do this for the first
2362                          * iclog we write to.
2363                          */
2364                         if (need_start_rec) {
2365                                 xlog_write_start_rec(ptr, ticket);
2366                                 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2367                                                 sizeof(struct xlog_op_header));
2368                         }
2369
2370                         ophdr = xlog_write_setup_ophdr(log, ptr, ticket, flags);
2371                         if (!ophdr)
2372                                 return -EIO;
2373
2374                         xlog_write_adv_cnt(&ptr, &len, &log_offset,
2375                                            sizeof(struct xlog_op_header));
2376
2377                         len += xlog_write_setup_copy(ticket, ophdr,
2378                                                      iclog->ic_size-log_offset,
2379                                                      reg->i_len,
2380                                                      &copy_off, &copy_len,
2381                                                      &partial_copy,
2382                                                      &partial_copy_len);
2383                         xlog_verify_dest_ptr(log, ptr);
2384
2385                         /*
2386                          * Copy region.
2387                          *
2388                          * Unmount records just log an opheader, so can have
2389                          * empty payloads with no data region to copy. Hence we
2390                          * only copy the payload if the vector says it has data
2391                          * to copy.
2392                          */
2393                         ASSERT(copy_len >= 0);
2394                         if (copy_len > 0) {
2395                                 memcpy(ptr, reg->i_addr + copy_off, copy_len);
2396                                 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2397                                                    copy_len);
2398                         }
2399                         copy_len += sizeof(struct xlog_op_header);
2400                         record_cnt++;
2401                         if (need_start_rec) {
2402                                 copy_len += sizeof(struct xlog_op_header);
2403                                 record_cnt++;
2404                                 need_start_rec = false;
2405                         }
2406                         data_cnt += contwr ? copy_len : 0;
2407
2408                         error = xlog_write_copy_finish(log, iclog, flags,
2409                                                        &record_cnt, &data_cnt,
2410                                                        &partial_copy,
2411                                                        &partial_copy_len,
2412                                                        log_offset,
2413                                                        commit_iclog);
2414                         if (error)
2415                                 return error;
2416
2417                         /*
2418                          * if we had a partial copy, we need to get more iclog
2419                          * space but we don't want to increment the region
2420                          * index because there is still more is this region to
2421                          * write.
2422                          *
2423                          * If we completed writing this region, and we flushed
2424                          * the iclog (indicated by resetting of the record
2425                          * count), then we also need to get more log space. If
2426                          * this was the last record, though, we are done and
2427                          * can just return.
2428                          */
2429                         if (partial_copy)
2430                                 break;
2431
2432                         if (++index == lv->lv_niovecs) {
2433 next_lv:
2434                                 lv = lv->lv_next;
2435                                 index = 0;
2436                                 if (lv)
2437                                         vecp = lv->lv_iovecp;
2438                         }
2439                         if (record_cnt == 0 && !ordered) {
2440                                 if (!lv)
2441                                         return 0;
2442                                 break;
2443                         }
2444                 }
2445         }
2446
2447         ASSERT(len == 0);
2448
2449         spin_lock(&log->l_icloglock);
2450         xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
2451         if (commit_iclog) {
2452                 ASSERT(flags & XLOG_COMMIT_TRANS);
2453                 *commit_iclog = iclog;
2454         } else {
2455                 error = xlog_state_release_iclog(log, iclog);
2456         }
2457         spin_unlock(&log->l_icloglock);
2458
2459         return error;
2460 }
2461
2462 static void
2463 xlog_state_activate_iclog(
2464         struct xlog_in_core     *iclog,
2465         int                     *iclogs_changed)
2466 {
2467         ASSERT(list_empty_careful(&iclog->ic_callbacks));
2468
2469         /*
2470          * If the number of ops in this iclog indicate it just contains the
2471          * dummy transaction, we can change state into IDLE (the second time
2472          * around). Otherwise we should change the state into NEED a dummy.
2473          * We don't need to cover the dummy.
2474          */
2475         if (*iclogs_changed == 0 &&
2476             iclog->ic_header.h_num_logops == cpu_to_be32(XLOG_COVER_OPS)) {
2477                 *iclogs_changed = 1;
2478         } else {
2479                 /*
2480                  * We have two dirty iclogs so start over.  This could also be
2481                  * num of ops indicating this is not the dummy going out.
2482                  */
2483                 *iclogs_changed = 2;
2484         }
2485
2486         iclog->ic_state = XLOG_STATE_ACTIVE;
2487         iclog->ic_offset = 0;
2488         iclog->ic_header.h_num_logops = 0;
2489         memset(iclog->ic_header.h_cycle_data, 0,
2490                 sizeof(iclog->ic_header.h_cycle_data));
2491         iclog->ic_header.h_lsn = 0;
2492 }
2493
2494 /*
2495  * Loop through all iclogs and mark all iclogs currently marked DIRTY as
2496  * ACTIVE after iclog I/O has completed.
2497  */
2498 static void
2499 xlog_state_activate_iclogs(
2500         struct xlog             *log,
2501         int                     *iclogs_changed)
2502 {
2503         struct xlog_in_core     *iclog = log->l_iclog;
2504
2505         do {
2506                 if (iclog->ic_state == XLOG_STATE_DIRTY)
2507                         xlog_state_activate_iclog(iclog, iclogs_changed);
2508                 /*
2509                  * The ordering of marking iclogs ACTIVE must be maintained, so
2510                  * an iclog doesn't become ACTIVE beyond one that is SYNCING.
2511                  */
2512                 else if (iclog->ic_state != XLOG_STATE_ACTIVE)
2513                         break;
2514         } while ((iclog = iclog->ic_next) != log->l_iclog);
2515 }
2516
2517 static int
2518 xlog_covered_state(
2519         int                     prev_state,
2520         int                     iclogs_changed)
2521 {
2522         /*
2523          * We usually go to NEED. But we go to NEED2 if the changed indicates we
2524          * are done writing the dummy record.  If we are done with the second
2525          * dummy recored (DONE2), then we go to IDLE.
2526          */
2527         switch (prev_state) {
2528         case XLOG_STATE_COVER_IDLE:
2529         case XLOG_STATE_COVER_NEED:
2530         case XLOG_STATE_COVER_NEED2:
2531                 break;
2532         case XLOG_STATE_COVER_DONE:
2533                 if (iclogs_changed == 1)
2534                         return XLOG_STATE_COVER_NEED2;
2535                 break;
2536         case XLOG_STATE_COVER_DONE2:
2537                 if (iclogs_changed == 1)
2538                         return XLOG_STATE_COVER_IDLE;
2539                 break;
2540         default:
2541                 ASSERT(0);
2542         }
2543
2544         return XLOG_STATE_COVER_NEED;
2545 }
2546
2547 STATIC void
2548 xlog_state_clean_iclog(
2549         struct xlog             *log,
2550         struct xlog_in_core     *dirty_iclog)
2551 {
2552         int                     iclogs_changed = 0;
2553
2554         dirty_iclog->ic_state = XLOG_STATE_DIRTY;
2555
2556         xlog_state_activate_iclogs(log, &iclogs_changed);
2557         wake_up_all(&dirty_iclog->ic_force_wait);
2558
2559         if (iclogs_changed) {
2560                 log->l_covered_state = xlog_covered_state(log->l_covered_state,
2561                                 iclogs_changed);
2562         }
2563 }
2564
2565 STATIC xfs_lsn_t
2566 xlog_get_lowest_lsn(
2567         struct xlog             *log)
2568 {
2569         struct xlog_in_core     *iclog = log->l_iclog;
2570         xfs_lsn_t               lowest_lsn = 0, lsn;
2571
2572         do {
2573                 if (iclog->ic_state == XLOG_STATE_ACTIVE ||
2574                     iclog->ic_state == XLOG_STATE_DIRTY)
2575                         continue;
2576
2577                 lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2578                 if ((lsn && !lowest_lsn) || XFS_LSN_CMP(lsn, lowest_lsn) < 0)
2579                         lowest_lsn = lsn;
2580         } while ((iclog = iclog->ic_next) != log->l_iclog);
2581
2582         return lowest_lsn;
2583 }
2584
2585 /*
2586  * Completion of a iclog IO does not imply that a transaction has completed, as
2587  * transactions can be large enough to span many iclogs. We cannot change the
2588  * tail of the log half way through a transaction as this may be the only
2589  * transaction in the log and moving the tail to point to the middle of it
2590  * will prevent recovery from finding the start of the transaction. Hence we
2591  * should only update the last_sync_lsn if this iclog contains transaction
2592  * completion callbacks on it.
2593  *
2594  * We have to do this before we drop the icloglock to ensure we are the only one
2595  * that can update it.
2596  *
2597  * If we are moving the last_sync_lsn forwards, we also need to ensure we kick
2598  * the reservation grant head pushing. This is due to the fact that the push
2599  * target is bound by the current last_sync_lsn value. Hence if we have a large
2600  * amount of log space bound up in this committing transaction then the
2601  * last_sync_lsn value may be the limiting factor preventing tail pushing from
2602  * freeing space in the log. Hence once we've updated the last_sync_lsn we
2603  * should push the AIL to ensure the push target (and hence the grant head) is
2604  * no longer bound by the old log head location and can move forwards and make
2605  * progress again.
2606  */
2607 static void
2608 xlog_state_set_callback(
2609         struct xlog             *log,
2610         struct xlog_in_core     *iclog,
2611         xfs_lsn_t               header_lsn)
2612 {
2613         iclog->ic_state = XLOG_STATE_CALLBACK;
2614
2615         ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
2616                            header_lsn) <= 0);
2617
2618         if (list_empty_careful(&iclog->ic_callbacks))
2619                 return;
2620
2621         atomic64_set(&log->l_last_sync_lsn, header_lsn);
2622         xlog_grant_push_ail(log, 0);
2623 }
2624
2625 /*
2626  * Return true if we need to stop processing, false to continue to the next
2627  * iclog. The caller will need to run callbacks if the iclog is returned in the
2628  * XLOG_STATE_CALLBACK state.
2629  */
2630 static bool
2631 xlog_state_iodone_process_iclog(
2632         struct xlog             *log,
2633         struct xlog_in_core     *iclog,
2634         bool                    *ioerror)
2635 {
2636         xfs_lsn_t               lowest_lsn;
2637         xfs_lsn_t               header_lsn;
2638
2639         switch (iclog->ic_state) {
2640         case XLOG_STATE_ACTIVE:
2641         case XLOG_STATE_DIRTY:
2642                 /*
2643                  * Skip all iclogs in the ACTIVE & DIRTY states:
2644                  */
2645                 return false;
2646         case XLOG_STATE_IOERROR:
2647                 /*
2648                  * Between marking a filesystem SHUTDOWN and stopping the log,
2649                  * we do flush all iclogs to disk (if there wasn't a log I/O
2650                  * error). So, we do want things to go smoothly in case of just
2651                  * a SHUTDOWN w/o a LOG_IO_ERROR.
2652                  */
2653                 *ioerror = true;
2654                 return false;
2655         case XLOG_STATE_DONE_SYNC:
2656                 /*
2657                  * Now that we have an iclog that is in the DONE_SYNC state, do
2658                  * one more check here to see if we have chased our tail around.
2659                  * If this is not the lowest lsn iclog, then we will leave it
2660                  * for another completion to process.
2661                  */
2662                 header_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2663                 lowest_lsn = xlog_get_lowest_lsn(log);
2664                 if (lowest_lsn && XFS_LSN_CMP(lowest_lsn, header_lsn) < 0)
2665                         return false;
2666                 xlog_state_set_callback(log, iclog, header_lsn);
2667                 return false;
2668         default:
2669                 /*
2670                  * Can only perform callbacks in order.  Since this iclog is not
2671                  * in the DONE_SYNC state, we skip the rest and just try to
2672                  * clean up.
2673                  */
2674                 return true;
2675         }
2676 }
2677
2678 /*
2679  * Keep processing entries in the iclog callback list until we come around and
2680  * it is empty.  We need to atomically see that the list is empty and change the
2681  * state to DIRTY so that we don't miss any more callbacks being added.
2682  *
2683  * This function is called with the icloglock held and returns with it held. We
2684  * drop it while running callbacks, however, as holding it over thousands of
2685  * callbacks is unnecessary and causes excessive contention if we do.
2686  */
2687 static void
2688 xlog_state_do_iclog_callbacks(
2689         struct xlog             *log,
2690         struct xlog_in_core     *iclog)
2691                 __releases(&log->l_icloglock)
2692                 __acquires(&log->l_icloglock)
2693 {
2694         spin_unlock(&log->l_icloglock);
2695         spin_lock(&iclog->ic_callback_lock);
2696         while (!list_empty(&iclog->ic_callbacks)) {
2697                 LIST_HEAD(tmp);
2698
2699                 list_splice_init(&iclog->ic_callbacks, &tmp);
2700
2701                 spin_unlock(&iclog->ic_callback_lock);
2702                 xlog_cil_process_committed(&tmp);
2703                 spin_lock(&iclog->ic_callback_lock);
2704         }
2705
2706         /*
2707          * Pick up the icloglock while still holding the callback lock so we
2708          * serialise against anyone trying to add more callbacks to this iclog
2709          * now we've finished processing.
2710          */
2711         spin_lock(&log->l_icloglock);
2712         spin_unlock(&iclog->ic_callback_lock);
2713 }
2714
2715 STATIC void
2716 xlog_state_do_callback(
2717         struct xlog             *log)
2718 {
2719         struct xlog_in_core     *iclog;
2720         struct xlog_in_core     *first_iclog;
2721         bool                    cycled_icloglock;
2722         bool                    ioerror;
2723         int                     flushcnt = 0;
2724         int                     repeats = 0;
2725
2726         spin_lock(&log->l_icloglock);
2727         do {
2728                 /*
2729                  * Scan all iclogs starting with the one pointed to by the
2730                  * log.  Reset this starting point each time the log is
2731                  * unlocked (during callbacks).
2732                  *
2733                  * Keep looping through iclogs until one full pass is made
2734                  * without running any callbacks.
2735                  */
2736                 first_iclog = log->l_iclog;
2737                 iclog = log->l_iclog;
2738                 cycled_icloglock = false;
2739                 ioerror = false;
2740                 repeats++;
2741
2742                 do {
2743                         if (xlog_state_iodone_process_iclog(log, iclog,
2744                                                         &ioerror))
2745                                 break;
2746
2747                         if (iclog->ic_state != XLOG_STATE_CALLBACK &&
2748                             iclog->ic_state != XLOG_STATE_IOERROR) {
2749                                 iclog = iclog->ic_next;
2750                                 continue;
2751                         }
2752
2753                         /*
2754                          * Running callbacks will drop the icloglock which means
2755                          * we'll have to run at least one more complete loop.
2756                          */
2757                         cycled_icloglock = true;
2758                         xlog_state_do_iclog_callbacks(log, iclog);
2759                         if (XLOG_FORCED_SHUTDOWN(log))
2760                                 wake_up_all(&iclog->ic_force_wait);
2761                         else
2762                                 xlog_state_clean_iclog(log, iclog);
2763                         iclog = iclog->ic_next;
2764                 } while (first_iclog != iclog);
2765
2766                 if (repeats > 5000) {
2767                         flushcnt += repeats;
2768                         repeats = 0;
2769                         xfs_warn(log->l_mp,
2770                                 "%s: possible infinite loop (%d iterations)",
2771                                 __func__, flushcnt);
2772                 }
2773         } while (!ioerror && cycled_icloglock);
2774
2775         if (log->l_iclog->ic_state == XLOG_STATE_ACTIVE ||
2776             log->l_iclog->ic_state == XLOG_STATE_IOERROR)
2777                 wake_up_all(&log->l_flush_wait);
2778
2779         spin_unlock(&log->l_icloglock);
2780 }
2781
2782
2783 /*
2784  * Finish transitioning this iclog to the dirty state.
2785  *
2786  * Make sure that we completely execute this routine only when this is
2787  * the last call to the iclog.  There is a good chance that iclog flushes,
2788  * when we reach the end of the physical log, get turned into 2 separate
2789  * calls to bwrite.  Hence, one iclog flush could generate two calls to this
2790  * routine.  By using the reference count bwritecnt, we guarantee that only
2791  * the second completion goes through.
2792  *
2793  * Callbacks could take time, so they are done outside the scope of the
2794  * global state machine log lock.
2795  */
2796 STATIC void
2797 xlog_state_done_syncing(
2798         struct xlog_in_core     *iclog)
2799 {
2800         struct xlog             *log = iclog->ic_log;
2801
2802         spin_lock(&log->l_icloglock);
2803         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
2804
2805         /*
2806          * If we got an error, either on the first buffer, or in the case of
2807          * split log writes, on the second, we shut down the file system and
2808          * no iclogs should ever be attempted to be written to disk again.
2809          */
2810         if (!XLOG_FORCED_SHUTDOWN(log)) {
2811                 ASSERT(iclog->ic_state == XLOG_STATE_SYNCING);
2812                 iclog->ic_state = XLOG_STATE_DONE_SYNC;
2813         }
2814
2815         /*
2816          * Someone could be sleeping prior to writing out the next
2817          * iclog buffer, we wake them all, one will get to do the
2818          * I/O, the others get to wait for the result.
2819          */
2820         wake_up_all(&iclog->ic_write_wait);
2821         spin_unlock(&log->l_icloglock);
2822         xlog_state_do_callback(log);
2823 }
2824
2825 /*
2826  * If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
2827  * sleep.  We wait on the flush queue on the head iclog as that should be
2828  * the first iclog to complete flushing. Hence if all iclogs are syncing,
2829  * we will wait here and all new writes will sleep until a sync completes.
2830  *
2831  * The in-core logs are used in a circular fashion. They are not used
2832  * out-of-order even when an iclog past the head is free.
2833  *
2834  * return:
2835  *      * log_offset where xlog_write() can start writing into the in-core
2836  *              log's data space.
2837  *      * in-core log pointer to which xlog_write() should write.
2838  *      * boolean indicating this is a continued write to an in-core log.
2839  *              If this is the last write, then the in-core log's offset field
2840  *              needs to be incremented, depending on the amount of data which
2841  *              is copied.
2842  */
2843 STATIC int
2844 xlog_state_get_iclog_space(
2845         struct xlog             *log,
2846         int                     len,
2847         struct xlog_in_core     **iclogp,
2848         struct xlog_ticket      *ticket,
2849         int                     *continued_write,
2850         int                     *logoffsetp)
2851 {
2852         int               log_offset;
2853         xlog_rec_header_t *head;
2854         xlog_in_core_t    *iclog;
2855
2856 restart:
2857         spin_lock(&log->l_icloglock);
2858         if (XLOG_FORCED_SHUTDOWN(log)) {
2859                 spin_unlock(&log->l_icloglock);
2860                 return -EIO;
2861         }
2862
2863         iclog = log->l_iclog;
2864         if (iclog->ic_state != XLOG_STATE_ACTIVE) {
2865                 XFS_STATS_INC(log->l_mp, xs_log_noiclogs);
2866
2867                 /* Wait for log writes to have flushed */
2868                 xlog_wait(&log->l_flush_wait, &log->l_icloglock);
2869                 goto restart;
2870         }
2871
2872         head = &iclog->ic_header;
2873
2874         atomic_inc(&iclog->ic_refcnt);  /* prevents sync */
2875         log_offset = iclog->ic_offset;
2876
2877         /* On the 1st write to an iclog, figure out lsn.  This works
2878          * if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
2879          * committing to.  If the offset is set, that's how many blocks
2880          * must be written.
2881          */
2882         if (log_offset == 0) {
2883                 ticket->t_curr_res -= log->l_iclog_hsize;
2884                 xlog_tic_add_region(ticket,
2885                                     log->l_iclog_hsize,
2886                                     XLOG_REG_TYPE_LRHEADER);
2887                 head->h_cycle = cpu_to_be32(log->l_curr_cycle);
2888                 head->h_lsn = cpu_to_be64(
2889                         xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
2890                 ASSERT(log->l_curr_block >= 0);
2891         }
2892
2893         /* If there is enough room to write everything, then do it.  Otherwise,
2894          * claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
2895          * bit is on, so this will get flushed out.  Don't update ic_offset
2896          * until you know exactly how many bytes get copied.  Therefore, wait
2897          * until later to update ic_offset.
2898          *
2899          * xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
2900          * can fit into remaining data section.
2901          */
2902         if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
2903                 int             error = 0;
2904
2905                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2906
2907                 /*
2908                  * If we are the only one writing to this iclog, sync it to
2909                  * disk.  We need to do an atomic compare and decrement here to
2910                  * avoid racing with concurrent atomic_dec_and_lock() calls in
2911                  * xlog_state_release_iclog() when there is more than one
2912                  * reference to the iclog.
2913                  */
2914                 if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1))
2915                         error = xlog_state_release_iclog(log, iclog);
2916                 spin_unlock(&log->l_icloglock);
2917                 if (error)
2918                         return error;
2919                 goto restart;
2920         }
2921
2922         /* Do we have enough room to write the full amount in the remainder
2923          * of this iclog?  Or must we continue a write on the next iclog and
2924          * mark this iclog as completely taken?  In the case where we switch
2925          * iclogs (to mark it taken), this particular iclog will release/sync
2926          * to disk in xlog_write().
2927          */
2928         if (len <= iclog->ic_size - iclog->ic_offset) {
2929                 *continued_write = 0;
2930                 iclog->ic_offset += len;
2931         } else {
2932                 *continued_write = 1;
2933                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2934         }
2935         *iclogp = iclog;
2936
2937         ASSERT(iclog->ic_offset <= iclog->ic_size);
2938         spin_unlock(&log->l_icloglock);
2939
2940         *logoffsetp = log_offset;
2941         return 0;
2942 }
2943
2944 /*
2945  * The first cnt-1 times a ticket goes through here we don't need to move the
2946  * grant write head because the permanent reservation has reserved cnt times the
2947  * unit amount.  Release part of current permanent unit reservation and reset
2948  * current reservation to be one units worth.  Also move grant reservation head
2949  * forward.
2950  */
2951 void
2952 xfs_log_ticket_regrant(
2953         struct xlog             *log,
2954         struct xlog_ticket      *ticket)
2955 {
2956         trace_xfs_log_ticket_regrant(log, ticket);
2957
2958         if (ticket->t_cnt > 0)
2959                 ticket->t_cnt--;
2960
2961         xlog_grant_sub_space(log, &log->l_reserve_head.grant,
2962                                         ticket->t_curr_res);
2963         xlog_grant_sub_space(log, &log->l_write_head.grant,
2964                                         ticket->t_curr_res);
2965         ticket->t_curr_res = ticket->t_unit_res;
2966         xlog_tic_reset_res(ticket);
2967
2968         trace_xfs_log_ticket_regrant_sub(log, ticket);
2969
2970         /* just return if we still have some of the pre-reserved space */
2971         if (!ticket->t_cnt) {
2972                 xlog_grant_add_space(log, &log->l_reserve_head.grant,
2973                                      ticket->t_unit_res);
2974                 trace_xfs_log_ticket_regrant_exit(log, ticket);
2975
2976                 ticket->t_curr_res = ticket->t_unit_res;
2977                 xlog_tic_reset_res(ticket);
2978         }
2979
2980         xfs_log_ticket_put(ticket);
2981 }
2982
2983 /*
2984  * Give back the space left from a reservation.
2985  *
2986  * All the information we need to make a correct determination of space left
2987  * is present.  For non-permanent reservations, things are quite easy.  The
2988  * count should have been decremented to zero.  We only need to deal with the
2989  * space remaining in the current reservation part of the ticket.  If the
2990  * ticket contains a permanent reservation, there may be left over space which
2991  * needs to be released.  A count of N means that N-1 refills of the current
2992  * reservation can be done before we need to ask for more space.  The first
2993  * one goes to fill up the first current reservation.  Once we run out of
2994  * space, the count will stay at zero and the only space remaining will be
2995  * in the current reservation field.
2996  */
2997 void
2998 xfs_log_ticket_ungrant(
2999         struct xlog             *log,
3000         struct xlog_ticket      *ticket)
3001 {
3002         int                     bytes;
3003
3004         trace_xfs_log_ticket_ungrant(log, ticket);
3005
3006         if (ticket->t_cnt > 0)
3007                 ticket->t_cnt--;
3008
3009         trace_xfs_log_ticket_ungrant_sub(log, ticket);
3010
3011         /*
3012          * If this is a permanent reservation ticket, we may be able to free
3013          * up more space based on the remaining count.
3014          */
3015         bytes = ticket->t_curr_res;
3016         if (ticket->t_cnt > 0) {
3017                 ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
3018                 bytes += ticket->t_unit_res*ticket->t_cnt;
3019         }
3020
3021         xlog_grant_sub_space(log, &log->l_reserve_head.grant, bytes);
3022         xlog_grant_sub_space(log, &log->l_write_head.grant, bytes);
3023
3024         trace_xfs_log_ticket_ungrant_exit(log, ticket);
3025
3026         xfs_log_space_wake(log->l_mp);
3027         xfs_log_ticket_put(ticket);
3028 }
3029
3030 /*
3031  * This routine will mark the current iclog in the ring as WANT_SYNC and move
3032  * the current iclog pointer to the next iclog in the ring.
3033  */
3034 STATIC void
3035 xlog_state_switch_iclogs(
3036         struct xlog             *log,
3037         struct xlog_in_core     *iclog,
3038         int                     eventual_size)
3039 {
3040         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
3041         assert_spin_locked(&log->l_icloglock);
3042
3043         if (!eventual_size)
3044                 eventual_size = iclog->ic_offset;
3045         iclog->ic_state = XLOG_STATE_WANT_SYNC;
3046         iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
3047         log->l_prev_block = log->l_curr_block;
3048         log->l_prev_cycle = log->l_curr_cycle;
3049
3050         /* roll log?: ic_offset changed later */
3051         log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
3052
3053         /* Round up to next log-sunit */
3054         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
3055             log->l_mp->m_sb.sb_logsunit > 1) {
3056                 uint32_t sunit_bb = BTOBB(log->l_mp->m_sb.sb_logsunit);
3057                 log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
3058         }
3059
3060         if (log->l_curr_block >= log->l_logBBsize) {
3061                 /*
3062                  * Rewind the current block before the cycle is bumped to make
3063                  * sure that the combined LSN never transiently moves forward
3064                  * when the log wraps to the next cycle. This is to support the
3065                  * unlocked sample of these fields from xlog_valid_lsn(). Most
3066                  * other cases should acquire l_icloglock.
3067                  */
3068                 log->l_curr_block -= log->l_logBBsize;
3069                 ASSERT(log->l_curr_block >= 0);
3070                 smp_wmb();
3071                 log->l_curr_cycle++;
3072                 if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
3073                         log->l_curr_cycle++;
3074         }
3075         ASSERT(iclog == log->l_iclog);
3076         log->l_iclog = iclog->ic_next;
3077 }
3078
3079 /*
3080  * Write out all data in the in-core log as of this exact moment in time.
3081  *
3082  * Data may be written to the in-core log during this call.  However,
3083  * we don't guarantee this data will be written out.  A change from past
3084  * implementation means this routine will *not* write out zero length LRs.
3085  *
3086  * Basically, we try and perform an intelligent scan of the in-core logs.
3087  * If we determine there is no flushable data, we just return.  There is no
3088  * flushable data if:
3089  *
3090  *      1. the current iclog is active and has no data; the previous iclog
3091  *              is in the active or dirty state.
3092  *      2. the current iclog is drity, and the previous iclog is in the
3093  *              active or dirty state.
3094  *
3095  * We may sleep if:
3096  *
3097  *      1. the current iclog is not in the active nor dirty state.
3098  *      2. the current iclog dirty, and the previous iclog is not in the
3099  *              active nor dirty state.
3100  *      3. the current iclog is active, and there is another thread writing
3101  *              to this particular iclog.
3102  *      4. a) the current iclog is active and has no other writers
3103  *         b) when we return from flushing out this iclog, it is still
3104  *              not in the active nor dirty state.
3105  */
3106 int
3107 xfs_log_force(
3108         struct xfs_mount        *mp,
3109         uint                    flags)
3110 {
3111         struct xlog             *log = mp->m_log;
3112         struct xlog_in_core     *iclog;
3113         xfs_lsn_t               lsn;
3114
3115         XFS_STATS_INC(mp, xs_log_force);
3116         trace_xfs_log_force(mp, 0, _RET_IP_);
3117
3118         xlog_cil_force(log);
3119
3120         spin_lock(&log->l_icloglock);
3121         iclog = log->l_iclog;
3122         if (iclog->ic_state == XLOG_STATE_IOERROR)
3123                 goto out_error;
3124
3125         if (iclog->ic_state == XLOG_STATE_DIRTY ||
3126             (iclog->ic_state == XLOG_STATE_ACTIVE &&
3127              atomic_read(&iclog->ic_refcnt) == 0 && iclog->ic_offset == 0)) {
3128                 /*
3129                  * If the head is dirty or (active and empty), then we need to
3130                  * look at the previous iclog.
3131                  *
3132                  * If the previous iclog is active or dirty we are done.  There
3133                  * is nothing to sync out. Otherwise, we attach ourselves to the
3134                  * previous iclog and go to sleep.
3135                  */
3136                 iclog = iclog->ic_prev;
3137         } else if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3138                 if (atomic_read(&iclog->ic_refcnt) == 0) {
3139                         /*
3140                          * We are the only one with access to this iclog.
3141                          *
3142                          * Flush it out now.  There should be a roundoff of zero
3143                          * to show that someone has already taken care of the
3144                          * roundoff from the previous sync.
3145                          */
3146                         atomic_inc(&iclog->ic_refcnt);
3147                         lsn = be64_to_cpu(iclog->ic_header.h_lsn);
3148                         xlog_state_switch_iclogs(log, iclog, 0);
3149                         if (xlog_state_release_iclog(log, iclog))
3150                                 goto out_error;
3151
3152                         if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn)
3153                                 goto out_unlock;
3154                 } else {
3155                         /*
3156                          * Someone else is writing to this iclog.
3157                          *
3158                          * Use its call to flush out the data.  However, the
3159                          * other thread may not force out this LR, so we mark
3160                          * it WANT_SYNC.
3161                          */
3162                         xlog_state_switch_iclogs(log, iclog, 0);
3163                 }
3164         } else {
3165                 /*
3166                  * If the head iclog is not active nor dirty, we just attach
3167                  * ourselves to the head and go to sleep if necessary.
3168                  */
3169                 ;
3170         }
3171
3172         if (flags & XFS_LOG_SYNC)
3173                 return xlog_wait_on_iclog(iclog);
3174 out_unlock:
3175         spin_unlock(&log->l_icloglock);
3176         return 0;
3177 out_error:
3178         spin_unlock(&log->l_icloglock);
3179         return -EIO;
3180 }
3181
3182 static int
3183 __xfs_log_force_lsn(
3184         struct xfs_mount        *mp,
3185         xfs_lsn_t               lsn,
3186         uint                    flags,
3187         int                     *log_flushed,
3188         bool                    already_slept)
3189 {
3190         struct xlog             *log = mp->m_log;
3191         struct xlog_in_core     *iclog;
3192
3193         spin_lock(&log->l_icloglock);
3194         iclog = log->l_iclog;
3195         if (iclog->ic_state == XLOG_STATE_IOERROR)
3196                 goto out_error;
3197
3198         while (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
3199                 iclog = iclog->ic_next;
3200                 if (iclog == log->l_iclog)
3201                         goto out_unlock;
3202         }
3203
3204         if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3205                 /*
3206                  * We sleep here if we haven't already slept (e.g. this is the
3207                  * first time we've looked at the correct iclog buf) and the
3208                  * buffer before us is going to be sync'ed.  The reason for this
3209                  * is that if we are doing sync transactions here, by waiting
3210                  * for the previous I/O to complete, we can allow a few more
3211                  * transactions into this iclog before we close it down.
3212                  *
3213                  * Otherwise, we mark the buffer WANT_SYNC, and bump up the
3214                  * refcnt so we can release the log (which drops the ref count).
3215                  * The state switch keeps new transaction commits from using
3216                  * this buffer.  When the current commits finish writing into
3217                  * the buffer, the refcount will drop to zero and the buffer
3218                  * will go out then.
3219                  */
3220                 if (!already_slept &&
3221                     (iclog->ic_prev->ic_state == XLOG_STATE_WANT_SYNC ||
3222                      iclog->ic_prev->ic_state == XLOG_STATE_SYNCING)) {
3223                         XFS_STATS_INC(mp, xs_log_force_sleep);
3224
3225                         xlog_wait(&iclog->ic_prev->ic_write_wait,
3226                                         &log->l_icloglock);
3227                         return -EAGAIN;
3228                 }
3229                 atomic_inc(&iclog->ic_refcnt);
3230                 xlog_state_switch_iclogs(log, iclog, 0);
3231                 if (xlog_state_release_iclog(log, iclog))
3232                         goto out_error;
3233                 if (log_flushed)
3234                         *log_flushed = 1;
3235         }
3236
3237         if (flags & XFS_LOG_SYNC)
3238                 return xlog_wait_on_iclog(iclog);
3239 out_unlock:
3240         spin_unlock(&log->l_icloglock);
3241         return 0;
3242 out_error:
3243         spin_unlock(&log->l_icloglock);
3244         return -EIO;
3245 }
3246
3247 /*
3248  * Force the in-core log to disk for a specific LSN.
3249  *
3250  * Find in-core log with lsn.
3251  *      If it is in the DIRTY state, just return.
3252  *      If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
3253  *              state and go to sleep or return.
3254  *      If it is in any other state, go to sleep or return.
3255  *
3256  * Synchronous forces are implemented with a wait queue.  All callers trying
3257  * to force a given lsn to disk must wait on the queue attached to the
3258  * specific in-core log.  When given in-core log finally completes its write
3259  * to disk, that thread will wake up all threads waiting on the queue.
3260  */
3261 int
3262 xfs_log_force_lsn(
3263         struct xfs_mount        *mp,
3264         xfs_lsn_t               lsn,
3265         uint                    flags,
3266         int                     *log_flushed)
3267 {
3268         int                     ret;
3269         ASSERT(lsn != 0);
3270
3271         XFS_STATS_INC(mp, xs_log_force);
3272         trace_xfs_log_force(mp, lsn, _RET_IP_);
3273
3274         lsn = xlog_cil_force_lsn(mp->m_log, lsn);
3275         if (lsn == NULLCOMMITLSN)
3276                 return 0;
3277
3278         ret = __xfs_log_force_lsn(mp, lsn, flags, log_flushed, false);
3279         if (ret == -EAGAIN)
3280                 ret = __xfs_log_force_lsn(mp, lsn, flags, log_flushed, true);
3281         return ret;
3282 }
3283
3284 /*
3285  * Free a used ticket when its refcount falls to zero.
3286  */
3287 void
3288 xfs_log_ticket_put(
3289         xlog_ticket_t   *ticket)
3290 {
3291         ASSERT(atomic_read(&ticket->t_ref) > 0);
3292         if (atomic_dec_and_test(&ticket->t_ref))
3293                 kmem_cache_free(xfs_log_ticket_zone, ticket);
3294 }
3295
3296 xlog_ticket_t *
3297 xfs_log_ticket_get(
3298         xlog_ticket_t   *ticket)
3299 {
3300         ASSERT(atomic_read(&ticket->t_ref) > 0);
3301         atomic_inc(&ticket->t_ref);
3302         return ticket;
3303 }
3304
3305 /*
3306  * Figure out the total log space unit (in bytes) that would be
3307  * required for a log ticket.
3308  */
3309 int
3310 xfs_log_calc_unit_res(
3311         struct xfs_mount        *mp,
3312         int                     unit_bytes)
3313 {
3314         struct xlog             *log = mp->m_log;
3315         int                     iclog_space;
3316         uint                    num_headers;
3317
3318         /*
3319          * Permanent reservations have up to 'cnt'-1 active log operations
3320          * in the log.  A unit in this case is the amount of space for one
3321          * of these log operations.  Normal reservations have a cnt of 1
3322          * and their unit amount is the total amount of space required.
3323          *
3324          * The following lines of code account for non-transaction data
3325          * which occupy space in the on-disk log.
3326          *
3327          * Normal form of a transaction is:
3328          * <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
3329          * and then there are LR hdrs, split-recs and roundoff at end of syncs.
3330          *
3331          * We need to account for all the leadup data and trailer data
3332          * around the transaction data.
3333          * And then we need to account for the worst case in terms of using
3334          * more space.
3335          * The worst case will happen if:
3336          * - the placement of the transaction happens to be such that the
3337          *   roundoff is at its maximum
3338          * - the transaction data is synced before the commit record is synced
3339          *   i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
3340          *   Therefore the commit record is in its own Log Record.
3341          *   This can happen as the commit record is called with its
3342          *   own region to xlog_write().
3343          *   This then means that in the worst case, roundoff can happen for
3344          *   the commit-rec as well.
3345          *   The commit-rec is smaller than padding in this scenario and so it is
3346          *   not added separately.
3347          */
3348
3349         /* for trans header */
3350         unit_bytes += sizeof(xlog_op_header_t);
3351         unit_bytes += sizeof(xfs_trans_header_t);
3352
3353         /* for start-rec */
3354         unit_bytes += sizeof(xlog_op_header_t);
3355
3356         /*
3357          * for LR headers - the space for data in an iclog is the size minus
3358          * the space used for the headers. If we use the iclog size, then we
3359          * undercalculate the number of headers required.
3360          *
3361          * Furthermore - the addition of op headers for split-recs might
3362          * increase the space required enough to require more log and op
3363          * headers, so take that into account too.
3364          *
3365          * IMPORTANT: This reservation makes the assumption that if this
3366          * transaction is the first in an iclog and hence has the LR headers
3367          * accounted to it, then the remaining space in the iclog is
3368          * exclusively for this transaction.  i.e. if the transaction is larger
3369          * than the iclog, it will be the only thing in that iclog.
3370          * Fundamentally, this means we must pass the entire log vector to
3371          * xlog_write to guarantee this.
3372          */
3373         iclog_space = log->l_iclog_size - log->l_iclog_hsize;
3374         num_headers = howmany(unit_bytes, iclog_space);
3375
3376         /* for split-recs - ophdrs added when data split over LRs */
3377         unit_bytes += sizeof(xlog_op_header_t) * num_headers;
3378
3379         /* add extra header reservations if we overrun */
3380         while (!num_headers ||
3381                howmany(unit_bytes, iclog_space) > num_headers) {
3382                 unit_bytes += sizeof(xlog_op_header_t);
3383                 num_headers++;
3384         }
3385         unit_bytes += log->l_iclog_hsize * num_headers;
3386
3387         /* for commit-rec LR header - note: padding will subsume the ophdr */
3388         unit_bytes += log->l_iclog_hsize;
3389
3390         /* for roundoff padding for transaction data and one for commit record */
3391         if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1) {
3392                 /* log su roundoff */
3393                 unit_bytes += 2 * mp->m_sb.sb_logsunit;
3394         } else {
3395                 /* BB roundoff */
3396                 unit_bytes += 2 * BBSIZE;
3397         }
3398
3399         return unit_bytes;
3400 }
3401
3402 /*
3403  * Allocate and initialise a new log ticket.
3404  */
3405 struct xlog_ticket *
3406 xlog_ticket_alloc(
3407         struct xlog             *log,
3408         int                     unit_bytes,
3409         int                     cnt,
3410         char                    client,
3411         bool                    permanent,
3412         xfs_km_flags_t          alloc_flags)
3413 {
3414         struct xlog_ticket      *tic;
3415         int                     unit_res;
3416
3417         tic = kmem_zone_zalloc(xfs_log_ticket_zone, alloc_flags);
3418         if (!tic)
3419                 return NULL;
3420
3421         unit_res = xfs_log_calc_unit_res(log->l_mp, unit_bytes);
3422
3423         atomic_set(&tic->t_ref, 1);
3424         tic->t_task             = current;
3425         INIT_LIST_HEAD(&tic->t_queue);
3426         tic->t_unit_res         = unit_res;
3427         tic->t_curr_res         = unit_res;
3428         tic->t_cnt              = cnt;
3429         tic->t_ocnt             = cnt;
3430         tic->t_tid              = prandom_u32();
3431         tic->t_clientid         = client;
3432         if (permanent)
3433                 tic->t_flags |= XLOG_TIC_PERM_RESERV;
3434
3435         xlog_tic_reset_res(tic);
3436
3437         return tic;
3438 }
3439
3440 #if defined(DEBUG)
3441 /*
3442  * Make sure that the destination ptr is within the valid data region of
3443  * one of the iclogs.  This uses backup pointers stored in a different
3444  * part of the log in case we trash the log structure.
3445  */
3446 STATIC void
3447 xlog_verify_dest_ptr(
3448         struct xlog     *log,
3449         void            *ptr)
3450 {
3451         int i;
3452         int good_ptr = 0;
3453
3454         for (i = 0; i < log->l_iclog_bufs; i++) {
3455                 if (ptr >= log->l_iclog_bak[i] &&
3456                     ptr <= log->l_iclog_bak[i] + log->l_iclog_size)
3457                         good_ptr++;
3458         }
3459
3460         if (!good_ptr)
3461                 xfs_emerg(log->l_mp, "%s: invalid ptr", __func__);
3462 }
3463
3464 /*
3465  * Check to make sure the grant write head didn't just over lap the tail.  If
3466  * the cycles are the same, we can't be overlapping.  Otherwise, make sure that
3467  * the cycles differ by exactly one and check the byte count.
3468  *
3469  * This check is run unlocked, so can give false positives. Rather than assert
3470  * on failures, use a warn-once flag and a panic tag to allow the admin to
3471  * determine if they want to panic the machine when such an error occurs. For
3472  * debug kernels this will have the same effect as using an assert but, unlinke
3473  * an assert, it can be turned off at runtime.
3474  */
3475 STATIC void
3476 xlog_verify_grant_tail(
3477         struct xlog     *log)
3478 {
3479         int             tail_cycle, tail_blocks;
3480         int             cycle, space;
3481
3482         xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &space);
3483         xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
3484         if (tail_cycle != cycle) {
3485                 if (cycle - 1 != tail_cycle &&
3486                     !(log->l_flags & XLOG_TAIL_WARN)) {
3487                         xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3488                                 "%s: cycle - 1 != tail_cycle", __func__);
3489                         log->l_flags |= XLOG_TAIL_WARN;
3490                 }
3491
3492                 if (space > BBTOB(tail_blocks) &&
3493                     !(log->l_flags & XLOG_TAIL_WARN)) {
3494                         xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3495                                 "%s: space > BBTOB(tail_blocks)", __func__);
3496                         log->l_flags |= XLOG_TAIL_WARN;
3497                 }
3498         }
3499 }
3500
3501 /* check if it will fit */
3502 STATIC void
3503 xlog_verify_tail_lsn(
3504         struct xlog             *log,
3505         struct xlog_in_core     *iclog,
3506         xfs_lsn_t               tail_lsn)
3507 {
3508     int blocks;
3509
3510     if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
3511         blocks =
3512             log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
3513         if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
3514                 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3515     } else {
3516         ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
3517
3518         if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
3519                 xfs_emerg(log->l_mp, "%s: tail wrapped", __func__);
3520
3521         blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
3522         if (blocks < BTOBB(iclog->ic_offset) + 1)
3523                 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3524     }
3525 }
3526
3527 /*
3528  * Perform a number of checks on the iclog before writing to disk.
3529  *
3530  * 1. Make sure the iclogs are still circular
3531  * 2. Make sure we have a good magic number
3532  * 3. Make sure we don't have magic numbers in the data
3533  * 4. Check fields of each log operation header for:
3534  *      A. Valid client identifier
3535  *      B. tid ptr value falls in valid ptr space (user space code)
3536  *      C. Length in log record header is correct according to the
3537  *              individual operation headers within record.
3538  * 5. When a bwrite will occur within 5 blocks of the front of the physical
3539  *      log, check the preceding blocks of the physical log to make sure all
3540  *      the cycle numbers agree with the current cycle number.
3541  */
3542 STATIC void
3543 xlog_verify_iclog(
3544         struct xlog             *log,
3545         struct xlog_in_core     *iclog,
3546         int                     count)
3547 {
3548         xlog_op_header_t        *ophead;
3549         xlog_in_core_t          *icptr;
3550         xlog_in_core_2_t        *xhdr;
3551         void                    *base_ptr, *ptr, *p;
3552         ptrdiff_t               field_offset;
3553         uint8_t                 clientid;
3554         int                     len, i, j, k, op_len;
3555         int                     idx;
3556
3557         /* check validity of iclog pointers */
3558         spin_lock(&log->l_icloglock);
3559         icptr = log->l_iclog;
3560         for (i = 0; i < log->l_iclog_bufs; i++, icptr = icptr->ic_next)
3561                 ASSERT(icptr);
3562
3563         if (icptr != log->l_iclog)
3564                 xfs_emerg(log->l_mp, "%s: corrupt iclog ring", __func__);
3565         spin_unlock(&log->l_icloglock);
3566
3567         /* check log magic numbers */
3568         if (iclog->ic_header.h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3569                 xfs_emerg(log->l_mp, "%s: invalid magic num", __func__);
3570
3571         base_ptr = ptr = &iclog->ic_header;
3572         p = &iclog->ic_header;
3573         for (ptr += BBSIZE; ptr < base_ptr + count; ptr += BBSIZE) {
3574                 if (*(__be32 *)ptr == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3575                         xfs_emerg(log->l_mp, "%s: unexpected magic num",
3576                                 __func__);
3577         }
3578
3579         /* check fields */
3580         len = be32_to_cpu(iclog->ic_header.h_num_logops);
3581         base_ptr = ptr = iclog->ic_datap;
3582         ophead = ptr;
3583         xhdr = iclog->ic_data;
3584         for (i = 0; i < len; i++) {
3585                 ophead = ptr;
3586
3587                 /* clientid is only 1 byte */
3588                 p = &ophead->oh_clientid;
3589                 field_offset = p - base_ptr;
3590                 if (field_offset & 0x1ff) {
3591                         clientid = ophead->oh_clientid;
3592                 } else {
3593                         idx = BTOBBT((char *)&ophead->oh_clientid - iclog->ic_datap);
3594                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3595                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3596                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3597                                 clientid = xlog_get_client_id(
3598                                         xhdr[j].hic_xheader.xh_cycle_data[k]);
3599                         } else {
3600                                 clientid = xlog_get_client_id(
3601                                         iclog->ic_header.h_cycle_data[idx]);
3602                         }
3603                 }
3604                 if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
3605                         xfs_warn(log->l_mp,
3606                                 "%s: invalid clientid %d op "PTR_FMT" offset 0x%lx",
3607                                 __func__, clientid, ophead,
3608                                 (unsigned long)field_offset);
3609
3610                 /* check length */
3611                 p = &ophead->oh_len;
3612                 field_offset = p - base_ptr;
3613                 if (field_offset & 0x1ff) {
3614                         op_len = be32_to_cpu(ophead->oh_len);
3615                 } else {
3616                         idx = BTOBBT((uintptr_t)&ophead->oh_len -
3617                                     (uintptr_t)iclog->ic_datap);
3618                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3619                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3620                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3621                                 op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
3622                         } else {
3623                                 op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
3624                         }
3625                 }
3626                 ptr += sizeof(xlog_op_header_t) + op_len;
3627         }
3628 }
3629 #endif
3630
3631 /*
3632  * Mark all iclogs IOERROR. l_icloglock is held by the caller.
3633  */
3634 STATIC int
3635 xlog_state_ioerror(
3636         struct xlog     *log)
3637 {
3638         xlog_in_core_t  *iclog, *ic;
3639
3640         iclog = log->l_iclog;
3641         if (iclog->ic_state != XLOG_STATE_IOERROR) {
3642                 /*
3643                  * Mark all the incore logs IOERROR.
3644                  * From now on, no log flushes will result.
3645                  */
3646                 ic = iclog;
3647                 do {
3648                         ic->ic_state = XLOG_STATE_IOERROR;
3649                         ic = ic->ic_next;
3650                 } while (ic != iclog);
3651                 return 0;
3652         }
3653         /*
3654          * Return non-zero, if state transition has already happened.
3655          */
3656         return 1;
3657 }
3658
3659 /*
3660  * This is called from xfs_force_shutdown, when we're forcibly
3661  * shutting down the filesystem, typically because of an IO error.
3662  * Our main objectives here are to make sure that:
3663  *      a. if !logerror, flush the logs to disk. Anything modified
3664  *         after this is ignored.
3665  *      b. the filesystem gets marked 'SHUTDOWN' for all interested
3666  *         parties to find out, 'atomically'.
3667  *      c. those who're sleeping on log reservations, pinned objects and
3668  *          other resources get woken up, and be told the bad news.
3669  *      d. nothing new gets queued up after (b) and (c) are done.
3670  *
3671  * Note: for the !logerror case we need to flush the regions held in memory out
3672  * to disk first. This needs to be done before the log is marked as shutdown,
3673  * otherwise the iclog writes will fail.
3674  */
3675 int
3676 xfs_log_force_umount(
3677         struct xfs_mount        *mp,
3678         int                     logerror)
3679 {
3680         struct xlog     *log;
3681         int             retval;
3682
3683         log = mp->m_log;
3684
3685         /*
3686          * If this happens during log recovery, don't worry about
3687          * locking; the log isn't open for business yet.
3688          */
3689         if (!log ||
3690             log->l_flags & XLOG_ACTIVE_RECOVERY) {
3691                 mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3692                 if (mp->m_sb_bp)
3693                         mp->m_sb_bp->b_flags |= XBF_DONE;
3694                 return 0;
3695         }
3696
3697         /*
3698          * Somebody could've already done the hard work for us.
3699          * No need to get locks for this.
3700          */
3701         if (logerror && log->l_iclog->ic_state == XLOG_STATE_IOERROR) {
3702                 ASSERT(XLOG_FORCED_SHUTDOWN(log));
3703                 return 1;
3704         }
3705
3706         /*
3707          * Flush all the completed transactions to disk before marking the log
3708          * being shut down. We need to do it in this order to ensure that
3709          * completed operations are safely on disk before we shut down, and that
3710          * we don't have to issue any buffer IO after the shutdown flags are set
3711          * to guarantee this.
3712          */
3713         if (!logerror)
3714                 xfs_log_force(mp, XFS_LOG_SYNC);
3715
3716         /*
3717          * mark the filesystem and the as in a shutdown state and wake
3718          * everybody up to tell them the bad news.
3719          */
3720         spin_lock(&log->l_icloglock);
3721         mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3722         if (mp->m_sb_bp)
3723                 mp->m_sb_bp->b_flags |= XBF_DONE;
3724
3725         /*
3726          * Mark the log and the iclogs with IO error flags to prevent any
3727          * further log IO from being issued or completed.
3728          */
3729         log->l_flags |= XLOG_IO_ERROR;
3730         retval = xlog_state_ioerror(log);
3731         spin_unlock(&log->l_icloglock);
3732
3733         /*
3734          * We don't want anybody waiting for log reservations after this. That
3735          * means we have to wake up everybody queued up on reserveq as well as
3736          * writeq.  In addition, we make sure in xlog_{re}grant_log_space that
3737          * we don't enqueue anything once the SHUTDOWN flag is set, and this
3738          * action is protected by the grant locks.
3739          */
3740         xlog_grant_head_wake_all(&log->l_reserve_head);
3741         xlog_grant_head_wake_all(&log->l_write_head);
3742
3743         /*
3744          * Wake up everybody waiting on xfs_log_force. Wake the CIL push first
3745          * as if the log writes were completed. The abort handling in the log
3746          * item committed callback functions will do this again under lock to
3747          * avoid races.
3748          */
3749         spin_lock(&log->l_cilp->xc_push_lock);
3750         wake_up_all(&log->l_cilp->xc_commit_wait);
3751         spin_unlock(&log->l_cilp->xc_push_lock);
3752         xlog_state_do_callback(log);
3753
3754         /* return non-zero if log IOERROR transition had already happened */
3755         return retval;
3756 }
3757
3758 STATIC int
3759 xlog_iclogs_empty(
3760         struct xlog     *log)
3761 {
3762         xlog_in_core_t  *iclog;
3763
3764         iclog = log->l_iclog;
3765         do {
3766                 /* endianness does not matter here, zero is zero in
3767                  * any language.
3768                  */
3769                 if (iclog->ic_header.h_num_logops)
3770                         return 0;
3771                 iclog = iclog->ic_next;
3772         } while (iclog != log->l_iclog);
3773         return 1;
3774 }
3775
3776 /*
3777  * Verify that an LSN stamped into a piece of metadata is valid. This is
3778  * intended for use in read verifiers on v5 superblocks.
3779  */
3780 bool
3781 xfs_log_check_lsn(
3782         struct xfs_mount        *mp,
3783         xfs_lsn_t               lsn)
3784 {
3785         struct xlog             *log = mp->m_log;
3786         bool                    valid;
3787
3788         /*
3789          * norecovery mode skips mount-time log processing and unconditionally
3790          * resets the in-core LSN. We can't validate in this mode, but
3791          * modifications are not allowed anyways so just return true.
3792          */
3793         if (mp->m_flags & XFS_MOUNT_NORECOVERY)
3794                 return true;
3795
3796         /*
3797          * Some metadata LSNs are initialized to NULL (e.g., the agfl). This is
3798          * handled by recovery and thus safe to ignore here.
3799          */
3800         if (lsn == NULLCOMMITLSN)
3801                 return true;
3802
3803         valid = xlog_valid_lsn(mp->m_log, lsn);
3804
3805         /* warn the user about what's gone wrong before verifier failure */
3806         if (!valid) {
3807                 spin_lock(&log->l_icloglock);
3808                 xfs_warn(mp,
3809 "Corruption warning: Metadata has LSN (%d:%d) ahead of current LSN (%d:%d). "
3810 "Please unmount and run xfs_repair (>= v4.3) to resolve.",
3811                          CYCLE_LSN(lsn), BLOCK_LSN(lsn),
3812                          log->l_curr_cycle, log->l_curr_block);
3813                 spin_unlock(&log->l_icloglock);
3814         }
3815
3816         return valid;
3817 }
3818
3819 bool
3820 xfs_log_in_recovery(
3821         struct xfs_mount        *mp)
3822 {
3823         struct xlog             *log = mp->m_log;
3824
3825         return log->l_flags & XLOG_ACTIVE_RECOVERY;
3826 }