fs/xfs/xfs_log.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   4  * All Rights Reserved.
   5  */
   6 #include "xfs.h"
   7 #include "xfs_fs.h"
   8 #include "xfs_shared.h"
   9 #include "xfs_format.h"
  10 #include "xfs_log_format.h"
  11 #include "xfs_trans_resv.h"
  12 #include "xfs_mount.h"
  13 #include "xfs_errortag.h"
  14 #include "xfs_error.h"
  15 #include "xfs_trans.h"
  16 #include "xfs_trans_priv.h"
  17 #include "xfs_log.h"
  18 #include "xfs_log_priv.h"
  19 #include "xfs_trace.h"
  20 #include "xfs_sysfs.h"
  21 #include "xfs_sb.h"
  22 #include "xfs_health.h"
  23
  24 kmem_zone_t     *xfs_log_ticket_zone;
  25
  26 /* Local miscellaneous function prototypes */
  27 STATIC int
  28 xlog_commit_record(
  29         struct xlog             *log,
  30         struct xlog_ticket      *ticket,
  31         struct xlog_in_core     **iclog,
  32         xfs_lsn_t               *commitlsnp);
  33
  34 STATIC struct xlog *
  35 xlog_alloc_log(
  36         struct xfs_mount        *mp,
  37         struct xfs_buftarg      *log_target,
  38         xfs_daddr_t             blk_offset,
  39         int                     num_bblks);
  40 STATIC int
  41 xlog_space_left(
  42         struct xlog             *log,
  43         atomic64_t              *head);
  44 STATIC void
  45 xlog_dealloc_log(
  46         struct xlog             *log);
  47
  48 /* local state machine functions */
  49 STATIC void xlog_state_done_syncing(
  50         struct xlog_in_core     *iclog,
  51         bool                    aborted);
  52 STATIC int
  53 xlog_state_get_iclog_space(
  54         struct xlog             *log,
  55         int                     len,
  56         struct xlog_in_core     **iclog,
  57         struct xlog_ticket      *ticket,
  58         int                     *continued_write,
  59         int                     *logoffsetp);
  60 STATIC int
  61 xlog_state_release_iclog(
  62         struct xlog             *log,
  63         struct xlog_in_core     *iclog);
  64 STATIC void
  65 xlog_state_switch_iclogs(
  66         struct xlog             *log,
  67         struct xlog_in_core     *iclog,
  68         int                     eventual_size);
  69 STATIC void
  70 xlog_state_want_sync(
  71         struct xlog             *log,
  72         struct xlog_in_core     *iclog);
  73
  74 STATIC void
  75 xlog_grant_push_ail(
  76         struct xlog             *log,
  77         int                     need_bytes);
  78 STATIC void
  79 xlog_regrant_reserve_log_space(
  80         struct xlog             *log,
  81         struct xlog_ticket      *ticket);
  82 STATIC void
  83 xlog_ungrant_log_space(
  84         struct xlog             *log,
  85         struct xlog_ticket      *ticket);
  86
  87 #if defined(DEBUG)
  88 STATIC void
  89 xlog_verify_dest_ptr(
  90         struct xlog             *log,
  91         void                    *ptr);
  92 STATIC void
  93 xlog_verify_grant_tail(
  94         struct xlog *log);
  95 STATIC void
  96 xlog_verify_iclog(
  97         struct xlog             *log,
  98         struct xlog_in_core     *iclog,
  99         int                     count);
 100 STATIC void
 101 xlog_verify_tail_lsn(
 102         struct xlog             *log,
 103         struct xlog_in_core     *iclog,
 104         xfs_lsn_t               tail_lsn);
 105 #else
 106 #define xlog_verify_dest_ptr(a,b)
 107 #define xlog_verify_grant_tail(a)
 108 #define xlog_verify_iclog(a,b,c)
 109 #define xlog_verify_tail_lsn(a,b,c)
 110 #endif
 111
 112 STATIC int
 113 xlog_iclogs_empty(
 114         struct xlog             *log);
 115
 116 static void
 117 xlog_grant_sub_space(
 118         struct xlog             *log,
 119         atomic64_t              *head,
 120         int                     bytes)
 121 {
 122         int64_t head_val = atomic64_read(head);
 123         int64_t new, old;
 124
 125         do {
 126                 int     cycle, space;
 127
 128                 xlog_crack_grant_head_val(head_val, &cycle, &space);
 129
 130                 space -= bytes;
 131                 if (space < 0) {
 132                         space += log->l_logsize;
 133                         cycle--;
 134                 }
 135
 136                 old = head_val;
 137                 new = xlog_assign_grant_head_val(cycle, space);
 138                 head_val = atomic64_cmpxchg(head, old, new);
 139         } while (head_val != old);
 140 }
 141
 142 static void
 143 xlog_grant_add_space(
 144         struct xlog             *log,
 145         atomic64_t              *head,
 146         int                     bytes)
 147 {
 148         int64_t head_val = atomic64_read(head);
 149         int64_t new, old;
 150
 151         do {
 152                 int             tmp;
 153                 int             cycle, space;
 154
 155                 xlog_crack_grant_head_val(head_val, &cycle, &space);
 156
 157                 tmp = log->l_logsize - space;
 158                 if (tmp > bytes)
 159                         space += bytes;
 160                 else {
 161                         space = bytes - tmp;
 162                         cycle++;
 163                 }
 164
 165                 old = head_val;
 166                 new = xlog_assign_grant_head_val(cycle, space);
 167                 head_val = atomic64_cmpxchg(head, old, new);
 168         } while (head_val != old);
 169 }
 170
 171 STATIC void
 172 xlog_grant_head_init(
 173         struct xlog_grant_head  *head)
 174 {
 175         xlog_assign_grant_head(&head->grant, 1, 0);
 176         INIT_LIST_HEAD(&head->waiters);
 177         spin_lock_init(&head->lock);
 178 }
 179
 180 STATIC void
 181 xlog_grant_head_wake_all(
 182         struct xlog_grant_head  *head)
 183 {
 184         struct xlog_ticket      *tic;
 185
 186         spin_lock(&head->lock);
 187         list_for_each_entry(tic, &head->waiters, t_queue)
 188                 wake_up_process(tic->t_task);
 189         spin_unlock(&head->lock);
 190 }
 191
 192 static inline int
 193 xlog_ticket_reservation(
 194         struct xlog             *log,
 195         struct xlog_grant_head  *head,
 196         struct xlog_ticket      *tic)
 197 {
 198         if (head == &log->l_write_head) {
 199                 ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
 200                 return tic->t_unit_res;
 201         } else {
 202                 if (tic->t_flags & XLOG_TIC_PERM_RESERV)
 203                         return tic->t_unit_res * tic->t_cnt;
 204                 else
 205                         return tic->t_unit_res;
 206         }
 207 }
 208
 209 STATIC bool
 210 xlog_grant_head_wake(
 211         struct xlog             *log,
 212         struct xlog_grant_head  *head,
 213         int                     *free_bytes)
 214 {
 215         struct xlog_ticket      *tic;
 216         int                     need_bytes;
 217
 218         list_for_each_entry(tic, &head->waiters, t_queue) {
 219                 need_bytes = xlog_ticket_reservation(log, head, tic);
 220                 if (*free_bytes < need_bytes)
 221                         return false;
 222
 223                 *free_bytes -= need_bytes;
 224                 trace_xfs_log_grant_wake_up(log, tic);
 225                 wake_up_process(tic->t_task);
 226         }
 227
 228         return true;
 229 }
 230
 231 STATIC int
 232 xlog_grant_head_wait(
 233         struct xlog             *log,
 234         struct xlog_grant_head  *head,
 235         struct xlog_ticket      *tic,
 236         int                     need_bytes) __releases(&head->lock)
 237                                             __acquires(&head->lock)
 238 {
 239         list_add_tail(&tic->t_queue, &head->waiters);
 240
 241         do {
 242                 if (XLOG_FORCED_SHUTDOWN(log))
 243                         goto shutdown;
 244                 xlog_grant_push_ail(log, need_bytes);
 245
 246                 __set_current_state(TASK_UNINTERRUPTIBLE);
 247                 spin_unlock(&head->lock);
 248
 249                 XFS_STATS_INC(log->l_mp, xs_sleep_logspace);
 250
 251                 trace_xfs_log_grant_sleep(log, tic);
 252                 schedule();
 253                 trace_xfs_log_grant_wake(log, tic);
 254
 255                 spin_lock(&head->lock);
 256                 if (XLOG_FORCED_SHUTDOWN(log))
 257                         goto shutdown;
 258         } while (xlog_space_left(log, &head->grant) < need_bytes);
 259
 260         list_del_init(&tic->t_queue);
 261         return 0;
 262 shutdown:
 263         list_del_init(&tic->t_queue);
 264         return -EIO;
 265 }
 266
 267 /*
 268  * Atomically get the log space required for a log ticket.
 269  *
 270  * Once a ticket gets put onto head->waiters, it will only return after the
 271  * needed reservation is satisfied.
 272  *
 273  * This function is structured so that it has a lock free fast path. This is
 274  * necessary because every new transaction reservation will come through this
 275  * path. Hence any lock will be globally hot if we take it unconditionally on
 276  * every pass.
 277  *
 278  * As tickets are only ever moved on and off head->waiters under head->lock, we
 279  * only need to take that lock if we are going to add the ticket to the queue
 280  * and sleep. We can avoid taking the lock if the ticket was never added to
 281  * head->waiters because the t_queue list head will be empty and we hold the
 282  * only reference to it so it can safely be checked unlocked.
 283  */
 284 STATIC int
 285 xlog_grant_head_check(
 286         struct xlog             *log,
 287         struct xlog_grant_head  *head,
 288         struct xlog_ticket      *tic,
 289         int                     *need_bytes)
 290 {
 291         int                     free_bytes;
 292         int                     error = 0;
 293
 294         ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
 295
 296         /*
 297          * If there are other waiters on the queue then give them a chance at
 298          * logspace before us.  Wake up the first waiters, if we do not wake
 299          * up all the waiters then go to sleep waiting for more free space,
 300          * otherwise try to get some space for this transaction.
 301          */
 302         *need_bytes = xlog_ticket_reservation(log, head, tic);
 303         free_bytes = xlog_space_left(log, &head->grant);
 304         if (!list_empty_careful(&head->waiters)) {
 305                 spin_lock(&head->lock);
 306                 if (!xlog_grant_head_wake(log, head, &free_bytes) ||
 307                     free_bytes < *need_bytes) {
 308                         error = xlog_grant_head_wait(log, head, tic,
 309                                                      *need_bytes);
 310                 }
 311                 spin_unlock(&head->lock);
 312         } else if (free_bytes < *need_bytes) {
 313                 spin_lock(&head->lock);
 314                 error = xlog_grant_head_wait(log, head, tic, *need_bytes);
 315                 spin_unlock(&head->lock);
 316         }
 317
 318         return error;
 319 }
 320
 321 static void
 322 xlog_tic_reset_res(xlog_ticket_t *tic)
 323 {
 324         tic->t_res_num = 0;
 325         tic->t_res_arr_sum = 0;
 326         tic->t_res_num_ophdrs = 0;
 327 }
 328
 329 static void
 330 xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type)
 331 {
 332         if (tic->t_res_num == XLOG_TIC_LEN_MAX) {
 333                 /* add to overflow and start again */
 334                 tic->t_res_o_flow += tic->t_res_arr_sum;
 335                 tic->t_res_num = 0;
 336                 tic->t_res_arr_sum = 0;
 337         }
 338
 339         tic->t_res_arr[tic->t_res_num].r_len = len;
 340         tic->t_res_arr[tic->t_res_num].r_type = type;
 341         tic->t_res_arr_sum += len;
 342         tic->t_res_num++;
 343 }
 344
 345 /*
 346  * Replenish the byte reservation required by moving the grant write head.
 347  */
 348 int
 349 xfs_log_regrant(
 350         struct xfs_mount        *mp,
 351         struct xlog_ticket      *tic)
 352 {
 353         struct xlog             *log = mp->m_log;
 354         int                     need_bytes;
 355         int                     error = 0;
 356
 357         if (XLOG_FORCED_SHUTDOWN(log))
 358                 return -EIO;
 359
 360         XFS_STATS_INC(mp, xs_try_logspace);
 361
 362         /*
 363          * This is a new transaction on the ticket, so we need to change the
 364          * transaction ID so that the next transaction has a different TID in
 365          * the log. Just add one to the existing tid so that we can see chains
 366          * of rolling transactions in the log easily.
 367          */
 368         tic->t_tid++;
 369
 370         xlog_grant_push_ail(log, tic->t_unit_res);
 371
 372         tic->t_curr_res = tic->t_unit_res;
 373         xlog_tic_reset_res(tic);
 374
 375         if (tic->t_cnt > 0)
 376                 return 0;
 377
 378         trace_xfs_log_regrant(log, tic);
 379
 380         error = xlog_grant_head_check(log, &log->l_write_head, tic,
 381                                       &need_bytes);
 382         if (error)
 383                 goto out_error;
 384
 385         xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
 386         trace_xfs_log_regrant_exit(log, tic);
 387         xlog_verify_grant_tail(log);
 388         return 0;
 389
 390 out_error:
 391         /*
 392          * If we are failing, make sure the ticket doesn't have any current
 393          * reservations.  We don't want to add this back when the ticket/
 394          * transaction gets cancelled.
 395          */
 396         tic->t_curr_res = 0;
 397         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
 398         return error;
 399 }
 400
 401 /*
 402  * Reserve log space and return a ticket corresponding to the reservation.
 403  *
 404  * Each reservation is going to reserve extra space for a log record header.
 405  * When writes happen to the on-disk log, we don't subtract the length of the
 406  * log record header from any reservation.  By wasting space in each
 407  * reservation, we prevent over allocation problems.
 408  */
 409 int
 410 xfs_log_reserve(
 411         struct xfs_mount        *mp,
 412         int                     unit_bytes,
 413         int                     cnt,
 414         struct xlog_ticket      **ticp,
 415         uint8_t                 client,
 416         bool                    permanent)
 417 {
 418         struct xlog             *log = mp->m_log;
 419         struct xlog_ticket      *tic;
 420         int                     need_bytes;
 421         int                     error = 0;
 422
 423         ASSERT(client == XFS_TRANSACTION || client == XFS_LOG);
 424
 425         if (XLOG_FORCED_SHUTDOWN(log))
 426                 return -EIO;
 427
 428         XFS_STATS_INC(mp, xs_try_logspace);
 429
 430         ASSERT(*ticp == NULL);
 431         tic = xlog_ticket_alloc(log, unit_bytes, cnt, client, permanent,
 432                                 KM_SLEEP | KM_MAYFAIL);
 433         if (!tic)
 434                 return -ENOMEM;
 435
 436         *ticp = tic;
 437
 438         xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt
 439                                             : tic->t_unit_res);
 440
 441         trace_xfs_log_reserve(log, tic);
 442
 443         error = xlog_grant_head_check(log, &log->l_reserve_head, tic,
 444                                       &need_bytes);
 445         if (error)
 446                 goto out_error;
 447
 448         xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes);
 449         xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
 450         trace_xfs_log_reserve_exit(log, tic);
 451         xlog_verify_grant_tail(log);
 452         return 0;
 453
 454 out_error:
 455         /*
 456          * If we are failing, make sure the ticket doesn't have any current
 457          * reservations.  We don't want to add this back when the ticket/
 458          * transaction gets cancelled.
 459          */
 460         tic->t_curr_res = 0;
 461         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
 462         return error;
 463 }
 464
 465
 466 /*
 467  * NOTES:
 468  *
 469  *      1. currblock field gets updated at startup and after in-core logs
 470  *              marked as with WANT_SYNC.
 471  */
 472
 473 /*
 474  * This routine is called when a user of a log manager ticket is done with
 475  * the reservation.  If the ticket was ever used, then a commit record for
 476  * the associated transaction is written out as a log operation header with
 477  * no data.  The flag XLOG_TIC_INITED is set when the first write occurs with
 478  * a given ticket.  If the ticket was one with a permanent reservation, then
 479  * a few operations are done differently.  Permanent reservation tickets by
 480  * default don't release the reservation.  They just commit the current
 481  * transaction with the belief that the reservation is still needed.  A flag
 482  * must be passed in before permanent reservations are actually released.
 483  * When these type of tickets are not released, they need to be set into
 484  * the inited state again.  By doing this, a start record will be written
 485  * out when the next write occurs.
 486  */
 487 xfs_lsn_t
 488 xfs_log_done(
 489         struct xfs_mount        *mp,
 490         struct xlog_ticket      *ticket,
 491         struct xlog_in_core     **iclog,
 492         bool                    regrant)
 493 {
 494         struct xlog             *log = mp->m_log;
 495         xfs_lsn_t               lsn = 0;
 496
 497         if (XLOG_FORCED_SHUTDOWN(log) ||
 498             /*
 499              * If nothing was ever written, don't write out commit record.
 500              * If we get an error, just continue and give back the log ticket.
 501              */
 502             (((ticket->t_flags & XLOG_TIC_INITED) == 0) &&
 503              (xlog_commit_record(log, ticket, iclog, &lsn)))) {
 504                 lsn = (xfs_lsn_t) -1;
 505                 regrant = false;
 506         }
 507
 508
 509         if (!regrant) {
 510                 trace_xfs_log_done_nonperm(log, ticket);
 511
 512                 /*
 513                  * Release ticket if not permanent reservation or a specific
 514                  * request has been made to release a permanent reservation.
 515                  */
 516                 xlog_ungrant_log_space(log, ticket);
 517         } else {
 518                 trace_xfs_log_done_perm(log, ticket);
 519
 520                 xlog_regrant_reserve_log_space(log, ticket);
 521                 /* If this ticket was a permanent reservation and we aren't
 522                  * trying to release it, reset the inited flags; so next time
 523                  * we write, a start record will be written out.
 524                  */
 525                 ticket->t_flags |= XLOG_TIC_INITED;
 526         }
 527
 528         xfs_log_ticket_put(ticket);
 529         return lsn;
 530 }
 531
 532 int
 533 xfs_log_release_iclog(
 534         struct xfs_mount        *mp,
 535         struct xlog_in_core     *iclog)
 536 {
 537         if (xlog_state_release_iclog(mp->m_log, iclog)) {
 538                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
 539                 return -EIO;
 540         }
 541
 542         return 0;
 543 }
 544
 545 /*
 546  * Mount a log filesystem
 547  *
 548  * mp           - ubiquitous xfs mount point structure
 549  * log_target   - buftarg of on-disk log device
 550  * blk_offset   - Start block # where block size is 512 bytes (BBSIZE)
 551  * num_bblocks  - Number of BBSIZE blocks in on-disk log
 552  *
 553  * Return error or zero.
 554  */
 555 int
 556 xfs_log_mount(
 557         xfs_mount_t     *mp,
 558         xfs_buftarg_t   *log_target,
 559         xfs_daddr_t     blk_offset,
 560         int             num_bblks)
 561 {
 562         bool            fatal = xfs_sb_version_hascrc(&mp->m_sb);
 563         int             error = 0;
 564         int             min_logfsbs;
 565
 566         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
 567                 xfs_notice(mp, "Mounting V%d Filesystem",
 568                            XFS_SB_VERSION_NUM(&mp->m_sb));
 569         } else {
 570                 xfs_notice(mp,
 571 "Mounting V%d filesystem in no-recovery mode. Filesystem will be inconsistent.",
 572                            XFS_SB_VERSION_NUM(&mp->m_sb));
 573                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 574         }
 575
 576         mp->m_log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
 577         if (IS_ERR(mp->m_log)) {
 578                 error = PTR_ERR(mp->m_log);
 579                 goto out;
 580         }
 581
 582         /*
 583          * Validate the given log space and drop a critical message via syslog
 584          * if the log size is too small that would lead to some unexpected
 585          * situations in transaction log space reservation stage.
 586          *
 587          * Note: we can't just reject the mount if the validation fails.  This
 588          * would mean that people would have to downgrade their kernel just to
 589          * remedy the situation as there is no way to grow the log (short of
 590          * black magic surgery with xfs_db).
 591          *
 592          * We can, however, reject mounts for CRC format filesystems, as the
 593          * mkfs binary being used to make the filesystem should never create a
 594          * filesystem with a log that is too small.
 595          */
 596         min_logfsbs = xfs_log_calc_minimum_size(mp);
 597
 598         if (mp->m_sb.sb_logblocks < min_logfsbs) {
 599                 xfs_warn(mp,
 600                 "Log size %d blocks too small, minimum size is %d blocks",
 601                          mp->m_sb.sb_logblocks, min_logfsbs);
 602                 error = -EINVAL;
 603         } else if (mp->m_sb.sb_logblocks > XFS_MAX_LOG_BLOCKS) {
 604                 xfs_warn(mp,
 605                 "Log size %d blocks too large, maximum size is %lld blocks",
 606                          mp->m_sb.sb_logblocks, XFS_MAX_LOG_BLOCKS);
 607                 error = -EINVAL;
 608         } else if (XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks) > XFS_MAX_LOG_BYTES) {
 609                 xfs_warn(mp,
 610                 "log size %lld bytes too large, maximum size is %lld bytes",
 611                          XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks),
 612                          XFS_MAX_LOG_BYTES);
 613                 error = -EINVAL;
 614         } else if (mp->m_sb.sb_logsunit > 1 &&
 615                    mp->m_sb.sb_logsunit % mp->m_sb.sb_blocksize) {
 616                 xfs_warn(mp,
 617                 "log stripe unit %u bytes must be a multiple of block size",
 618                          mp->m_sb.sb_logsunit);
 619                 error = -EINVAL;
 620                 fatal = true;
 621         }
 622         if (error) {
 623                 /*
 624                  * Log check errors are always fatal on v5; or whenever bad
 625                  * metadata leads to a crash.
 626                  */
 627                 if (fatal) {
 628                         xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
 629                         ASSERT(0);
 630                         goto out_free_log;
 631                 }
 632                 xfs_crit(mp, "Log size out of supported range.");
 633                 xfs_crit(mp,
 634 "Continuing onwards, but if log hangs are experienced then please report this message in the bug report.");
 635         }
 636
 637         /*
 638          * Initialize the AIL now we have a log.
 639          */
 640         error = xfs_trans_ail_init(mp);
 641         if (error) {
 642                 xfs_warn(mp, "AIL initialisation failed: error %d", error);
 643                 goto out_free_log;
 644         }
 645         mp->m_log->l_ailp = mp->m_ail;
 646
 647         /*
 648          * skip log recovery on a norecovery mount.  pretend it all
 649          * just worked.
 650          */
 651         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
 652                 int     readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
 653
 654                 if (readonly)
 655                         mp->m_flags &= ~XFS_MOUNT_RDONLY;
 656
 657                 error = xlog_recover(mp->m_log);
 658
 659                 if (readonly)
 660                         mp->m_flags |= XFS_MOUNT_RDONLY;
 661                 if (error) {
 662                         xfs_warn(mp, "log mount/recovery failed: error %d",
 663                                 error);
 664                         xlog_recover_cancel(mp->m_log);
 665                         goto out_destroy_ail;
 666                 }
 667         }
 668
 669         error = xfs_sysfs_init(&mp->m_log->l_kobj, &xfs_log_ktype, &mp->m_kobj,
 670                                "log");
 671         if (error)
 672                 goto out_destroy_ail;
 673
 674         /* Normal transactions can now occur */
 675         mp->m_log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
 676
 677         /*
 678          * Now the log has been fully initialised and we know were our
 679          * space grant counters are, we can initialise the permanent ticket
 680          * needed for delayed logging to work.
 681          */
 682         xlog_cil_init_post_recovery(mp->m_log);
 683
 684         return 0;
 685
 686 out_destroy_ail:
 687         xfs_trans_ail_destroy(mp);
 688 out_free_log:
 689         xlog_dealloc_log(mp->m_log);
 690 out:
 691         return error;
 692 }
 693
 694 /*
 695  * Finish the recovery of the file system.  This is separate from the
 696  * xfs_log_mount() call, because it depends on the code in xfs_mountfs() to read
 697  * in the root and real-time bitmap inodes between calling xfs_log_mount() and
 698  * here.
 699  *
 700  * If we finish recovery successfully, start the background log work. If we are
 701  * not doing recovery, then we have a RO filesystem and we don't need to start
 702  * it.
 703  */
 704 int
 705 xfs_log_mount_finish(
 706         struct xfs_mount        *mp)
 707 {
 708         int     error = 0;
 709         bool    readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
 710         bool    recovered = mp->m_log->l_flags & XLOG_RECOVERY_NEEDED;
 711
 712         if (mp->m_flags & XFS_MOUNT_NORECOVERY) {
 713                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 714                 return 0;
 715         } else if (readonly) {
 716                 /* Allow unlinked processing to proceed */
 717                 mp->m_flags &= ~XFS_MOUNT_RDONLY;
 718         }
 719
 720         /*
 721          * During the second phase of log recovery, we need iget and
 722          * iput to behave like they do for an active filesystem.
 723          * xfs_fs_drop_inode needs to be able to prevent the deletion
 724          * of inodes before we're done replaying log items on those
 725          * inodes.  Turn it off immediately after recovery finishes
 726          * so that we don't leak the quota inodes if subsequent mount
 727          * activities fail.
 728          *
 729          * We let all inodes involved in redo item processing end up on
 730          * the LRU instead of being evicted immediately so that if we do
 731          * something to an unlinked inode, the irele won't cause
 732          * premature truncation and freeing of the inode, which results
 733          * in log recovery failure.  We have to evict the unreferenced
 734          * lru inodes after clearing SB_ACTIVE because we don't
 735          * otherwise clean up the lru if there's a subsequent failure in
 736          * xfs_mountfs, which leads to us leaking the inodes if nothing
 737          * else (e.g. quotacheck) references the inodes before the
 738          * mount failure occurs.
 739          */
 740         mp->m_super->s_flags |= SB_ACTIVE;
 741         error = xlog_recover_finish(mp->m_log);
 742         if (!error)
 743                 xfs_log_work_queue(mp);
 744         mp->m_super->s_flags &= ~SB_ACTIVE;
 745         evict_inodes(mp->m_super);
 746
 747         /*
 748          * Drain the buffer LRU after log recovery. This is required for v4
 749          * filesystems to avoid leaving around buffers with NULL verifier ops,
 750          * but we do it unconditionally to make sure we're always in a clean
 751          * cache state after mount.
 752          *
 753          * Don't push in the error case because the AIL may have pending intents
 754          * that aren't removed until recovery is cancelled.
 755          */
 756         if (!error && recovered) {
 757                 xfs_log_force(mp, XFS_LOG_SYNC);
 758                 xfs_ail_push_all_sync(mp->m_ail);
 759         }
 760         xfs_wait_buftarg(mp->m_ddev_targp);
 761
 762         if (readonly)
 763                 mp->m_flags |= XFS_MOUNT_RDONLY;
 764
 765         return error;
 766 }
 767
 768 /*
 769  * The mount has failed. Cancel the recovery if it hasn't completed and destroy
 770  * the log.
 771  */
 772 int
 773 xfs_log_mount_cancel(
 774         struct xfs_mount        *mp)
 775 {
 776         int                     error;
 777
 778         error = xlog_recover_cancel(mp->m_log);
 779         xfs_log_unmount(mp);
 780
 781         return error;
 782 }
 783
 784 /*
 785  * Final log writes as part of unmount.
 786  *
 787  * Mark the filesystem clean as unmount happens.  Note that during relocation
 788  * this routine needs to be executed as part of source-bag while the
 789  * deallocation must not be done until source-end.
 790  */
 791
 792 /* Actually write the unmount record to disk. */
 793 static void
 794 xfs_log_write_unmount_record(
 795         struct xfs_mount        *mp)
 796 {
 797         /* the data section must be 32 bit size aligned */
 798         struct xfs_unmount_log_format magic = {
 799                 .magic = XLOG_UNMOUNT_TYPE,
 800         };
 801         struct xfs_log_iovec reg = {
 802                 .i_addr = &magic,
 803                 .i_len = sizeof(magic),
 804                 .i_type = XLOG_REG_TYPE_UNMOUNT,
 805         };
 806         struct xfs_log_vec vec = {
 807                 .lv_niovecs = 1,
 808                 .lv_iovecp = &reg,
 809         };
 810         struct xlog             *log = mp->m_log;
 811         struct xlog_in_core     *iclog;
 812         struct xlog_ticket      *tic = NULL;
 813         xfs_lsn_t               lsn;
 814         uint                    flags = XLOG_UNMOUNT_TRANS;
 815         int                     error;
 816
 817         error = xfs_log_reserve(mp, 600, 1, &tic, XFS_LOG, 0);
 818         if (error)
 819                 goto out_err;
 820
 821         /*
 822          * If we think the summary counters are bad, clear the unmount header
 823          * flag in the unmount record so that the summary counters will be
 824          * recalculated during log recovery at next mount.  Refer to
 825          * xlog_check_unmount_rec for more details.
 826          */
 827         if (XFS_TEST_ERROR(xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS), mp,
 828                         XFS_ERRTAG_FORCE_SUMMARY_RECALC)) {
 829                 xfs_alert(mp, "%s: will fix summary counters at next mount",
 830                                 __func__);
 831                 flags &= ~XLOG_UNMOUNT_TRANS;
 832         }
 833
 834         /* remove inited flag, and account for space used */
 835         tic->t_flags = 0;
 836         tic->t_curr_res -= sizeof(magic);
 837         error = xlog_write(log, &vec, tic, &lsn, NULL, flags);
 838         /*
 839          * At this point, we're umounting anyway, so there's no point in
 840          * transitioning log state to IOERROR. Just continue...
 841          */
 842 out_err:
 843         if (error)
 844                 xfs_alert(mp, "%s: unmount record failed", __func__);
 845
 846         spin_lock(&log->l_icloglock);
 847         iclog = log->l_iclog;
 848         atomic_inc(&iclog->ic_refcnt);
 849         xlog_state_want_sync(log, iclog);
 850         spin_unlock(&log->l_icloglock);
 851         error = xlog_state_release_iclog(log, iclog);
 852
 853         spin_lock(&log->l_icloglock);
 854         switch (iclog->ic_state) {
 855         default:
 856                 if (!XLOG_FORCED_SHUTDOWN(log)) {
 857                         xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
 858                         break;
 859                 }
 860                 /* fall through */
 861         case XLOG_STATE_ACTIVE:
 862         case XLOG_STATE_DIRTY:
 863                 spin_unlock(&log->l_icloglock);
 864                 break;
 865         }
 866
 867         if (tic) {
 868                 trace_xfs_log_umount_write(log, tic);
 869                 xlog_ungrant_log_space(log, tic);
 870                 xfs_log_ticket_put(tic);
 871         }
 872 }
 873
 874 /*
 875  * Unmount record used to have a string "Unmount filesystem--" in the
 876  * data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
 877  * We just write the magic number now since that particular field isn't
 878  * currently architecture converted and "Unmount" is a bit foo.
 879  * As far as I know, there weren't any dependencies on the old behaviour.
 880  */
 881
 882 static int
 883 xfs_log_unmount_write(xfs_mount_t *mp)
 884 {
 885         struct xlog      *log = mp->m_log;
 886         xlog_in_core_t   *iclog;
 887 #ifdef DEBUG
 888         xlog_in_core_t   *first_iclog;
 889 #endif
 890         int              error;
 891
 892         /*
 893          * Don't write out unmount record on norecovery mounts or ro devices.
 894          * Or, if we are doing a forced umount (typically because of IO errors).
 895          */
 896         if (mp->m_flags & XFS_MOUNT_NORECOVERY ||
 897             xfs_readonly_buftarg(log->l_targ)) {
 898                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 899                 return 0;
 900         }
 901
 902         error = xfs_log_force(mp, XFS_LOG_SYNC);
 903         ASSERT(error || !(XLOG_FORCED_SHUTDOWN(log)));
 904
 905 #ifdef DEBUG
 906         first_iclog = iclog = log->l_iclog;
 907         do {
 908                 if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
 909                         ASSERT(iclog->ic_state & XLOG_STATE_ACTIVE);
 910                         ASSERT(iclog->ic_offset == 0);
 911                 }
 912                 iclog = iclog->ic_next;
 913         } while (iclog != first_iclog);
 914 #endif
 915         if (! (XLOG_FORCED_SHUTDOWN(log))) {
 916                 xfs_log_write_unmount_record(mp);
 917         } else {
 918                 /*
 919                  * We're already in forced_shutdown mode, couldn't
 920                  * even attempt to write out the unmount transaction.
 921                  *
 922                  * Go through the motions of sync'ing and releasing
 923                  * the iclog, even though no I/O will actually happen,
 924                  * we need to wait for other log I/Os that may already
 925                  * be in progress.  Do this as a separate section of
 926                  * code so we'll know if we ever get stuck here that
 927                  * we're in this odd situation of trying to unmount
 928                  * a file system that went into forced_shutdown as
 929                  * the result of an unmount..
 930                  */
 931                 spin_lock(&log->l_icloglock);
 932                 iclog = log->l_iclog;
 933                 atomic_inc(&iclog->ic_refcnt);
 934
 935                 xlog_state_want_sync(log, iclog);
 936                 spin_unlock(&log->l_icloglock);
 937                 error =  xlog_state_release_iclog(log, iclog);
 938
 939                 spin_lock(&log->l_icloglock);
 940
 941                 if ( ! (   iclog->ic_state == XLOG_STATE_ACTIVE
 942                         || iclog->ic_state == XLOG_STATE_DIRTY
 943                         || iclog->ic_state == XLOG_STATE_IOERROR) ) {
 944
 945                                 xlog_wait(&iclog->ic_force_wait,
 946                                                         &log->l_icloglock);
 947                 } else {
 948                         spin_unlock(&log->l_icloglock);
 949                 }
 950         }
 951
 952         return error;
 953 }       /* xfs_log_unmount_write */
 954
 955 /*
 956  * Empty the log for unmount/freeze.
 957  *
 958  * To do this, we first need to shut down the background log work so it is not
 959  * trying to cover the log as we clean up. We then need to unpin all objects in
 960  * the log so we can then flush them out. Once they have completed their IO and
 961  * run the callbacks removing themselves from the AIL, we can write the unmount
 962  * record.
 963  */
 964 void
 965 xfs_log_quiesce(
 966         struct xfs_mount        *mp)
 967 {
 968         cancel_delayed_work_sync(&mp->m_log->l_work);
 969         xfs_log_force(mp, XFS_LOG_SYNC);
 970
 971         /*
 972          * The superblock buffer is uncached and while xfs_ail_push_all_sync()
 973          * will push it, xfs_wait_buftarg() will not wait for it. Further,
 974          * xfs_buf_iowait() cannot be used because it was pushed with the
 975          * XBF_ASYNC flag set, so we need to use a lock/unlock pair to wait for
 976          * the IO to complete.
 977          */
 978         xfs_ail_push_all_sync(mp->m_ail);
 979         xfs_wait_buftarg(mp->m_ddev_targp);
 980         xfs_buf_lock(mp->m_sb_bp);
 981         xfs_buf_unlock(mp->m_sb_bp);
 982
 983         xfs_log_unmount_write(mp);
 984 }
 985
 986 /*
 987  * Shut down and release the AIL and Log.
 988  *
 989  * During unmount, we need to ensure we flush all the dirty metadata objects
 990  * from the AIL so that the log is empty before we write the unmount record to
 991  * the log. Once this is done, we can tear down the AIL and the log.
 992  */
 993 void
 994 xfs_log_unmount(
 995         struct xfs_mount        *mp)
 996 {
 997         xfs_log_quiesce(mp);
 998
 999         xfs_trans_ail_destroy(mp);
1000
1001         xfs_sysfs_del(&mp->m_log->l_kobj);
1002
1003         xlog_dealloc_log(mp->m_log);
1004 }
1005
1006 void
1007 xfs_log_item_init(
1008         struct xfs_mount        *mp,
1009         struct xfs_log_item     *item,
1010         int                     type,
1011         const struct xfs_item_ops *ops)
1012 {
1013         item->li_mountp = mp;
1014         item->li_ailp = mp->m_ail;
1015         item->li_type = type;
1016         item->li_ops = ops;
1017         item->li_lv = NULL;
1018
1019         INIT_LIST_HEAD(&item->li_ail);
1020         INIT_LIST_HEAD(&item->li_cil);
1021         INIT_LIST_HEAD(&item->li_bio_list);
1022         INIT_LIST_HEAD(&item->li_trans);
1023 }
1024
1025 /*
1026  * Wake up processes waiting for log space after we have moved the log tail.
1027  */
1028 void
1029 xfs_log_space_wake(
1030         struct xfs_mount        *mp)
1031 {
1032         struct xlog             *log = mp->m_log;
1033         int                     free_bytes;
1034
1035         if (XLOG_FORCED_SHUTDOWN(log))
1036                 return;
1037
1038         if (!list_empty_careful(&log->l_write_head.waiters)) {
1039                 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
1040
1041                 spin_lock(&log->l_write_head.lock);
1042                 free_bytes = xlog_space_left(log, &log->l_write_head.grant);
1043                 xlog_grant_head_wake(log, &log->l_write_head, &free_bytes);
1044                 spin_unlock(&log->l_write_head.lock);
1045         }
1046
1047         if (!list_empty_careful(&log->l_reserve_head.waiters)) {
1048                 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
1049
1050                 spin_lock(&log->l_reserve_head.lock);
1051                 free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1052                 xlog_grant_head_wake(log, &log->l_reserve_head, &free_bytes);
1053                 spin_unlock(&log->l_reserve_head.lock);
1054         }
1055 }
1056
1057 /*
1058  * Determine if we have a transaction that has gone to disk that needs to be
1059  * covered. To begin the transition to the idle state firstly the log needs to
1060  * be idle. That means the CIL, the AIL and the iclogs needs to be empty before
1061  * we start attempting to cover the log.
1062  *
1063  * Only if we are then in a state where covering is needed, the caller is
1064  * informed that dummy transactions are required to move the log into the idle
1065  * state.
1066  *
1067  * If there are any items in the AIl or CIL, then we do not want to attempt to
1068  * cover the log as we may be in a situation where there isn't log space
1069  * available to run a dummy transaction and this can lead to deadlocks when the
1070  * tail of the log is pinned by an item that is modified in the CIL.  Hence
1071  * there's no point in running a dummy transaction at this point because we
1072  * can't start trying to idle the log until both the CIL and AIL are empty.
1073  */
1074 static int
1075 xfs_log_need_covered(xfs_mount_t *mp)
1076 {
1077         struct xlog     *log = mp->m_log;
1078         int             needed = 0;
1079
1080         if (!xfs_fs_writable(mp, SB_FREEZE_WRITE))
1081                 return 0;
1082
1083         if (!xlog_cil_empty(log))
1084                 return 0;
1085
1086         spin_lock(&log->l_icloglock);
1087         switch (log->l_covered_state) {
1088         case XLOG_STATE_COVER_DONE:
1089         case XLOG_STATE_COVER_DONE2:
1090         case XLOG_STATE_COVER_IDLE:
1091                 break;
1092         case XLOG_STATE_COVER_NEED:
1093         case XLOG_STATE_COVER_NEED2:
1094                 if (xfs_ail_min_lsn(log->l_ailp))
1095                         break;
1096                 if (!xlog_iclogs_empty(log))
1097                         break;
1098
1099                 needed = 1;
1100                 if (log->l_covered_state == XLOG_STATE_COVER_NEED)
1101                         log->l_covered_state = XLOG_STATE_COVER_DONE;
1102                 else
1103                         log->l_covered_state = XLOG_STATE_COVER_DONE2;
1104                 break;
1105         default:
1106                 needed = 1;
1107                 break;
1108         }
1109         spin_unlock(&log->l_icloglock);
1110         return needed;
1111 }
1112
1113 /*
1114  * We may be holding the log iclog lock upon entering this routine.
1115  */
1116 xfs_lsn_t
1117 xlog_assign_tail_lsn_locked(
1118         struct xfs_mount        *mp)
1119 {
1120         struct xlog             *log = mp->m_log;
1121         struct xfs_log_item     *lip;
1122         xfs_lsn_t               tail_lsn;
1123
1124         assert_spin_locked(&mp->m_ail->ail_lock);
1125
1126         /*
1127          * To make sure we always have a valid LSN for the log tail we keep
1128          * track of the last LSN which was committed in log->l_last_sync_lsn,
1129          * and use that when the AIL was empty.
1130          */
1131         lip = xfs_ail_min(mp->m_ail);
1132         if (lip)
1133                 tail_lsn = lip->li_lsn;
1134         else
1135                 tail_lsn = atomic64_read(&log->l_last_sync_lsn);
1136         trace_xfs_log_assign_tail_lsn(log, tail_lsn);
1137         atomic64_set(&log->l_tail_lsn, tail_lsn);
1138         return tail_lsn;
1139 }
1140
1141 xfs_lsn_t
1142 xlog_assign_tail_lsn(
1143         struct xfs_mount        *mp)
1144 {
1145         xfs_lsn_t               tail_lsn;
1146
1147         spin_lock(&mp->m_ail->ail_lock);
1148         tail_lsn = xlog_assign_tail_lsn_locked(mp);
1149         spin_unlock(&mp->m_ail->ail_lock);
1150
1151         return tail_lsn;
1152 }
1153
1154 /*
1155  * Return the space in the log between the tail and the head.  The head
1156  * is passed in the cycle/bytes formal parms.  In the special case where
1157  * the reserve head has wrapped passed the tail, this calculation is no
1158  * longer valid.  In this case, just return 0 which means there is no space
1159  * in the log.  This works for all places where this function is called
1160  * with the reserve head.  Of course, if the write head were to ever
1161  * wrap the tail, we should blow up.  Rather than catch this case here,
1162  * we depend on other ASSERTions in other parts of the code.   XXXmiken
1163  *
1164  * This code also handles the case where the reservation head is behind
1165  * the tail.  The details of this case are described below, but the end
1166  * result is that we return the size of the log as the amount of space left.
1167  */
1168 STATIC int
1169 xlog_space_left(
1170         struct xlog     *log,
1171         atomic64_t      *head)
1172 {
1173         int             free_bytes;
1174         int             tail_bytes;
1175         int             tail_cycle;
1176         int             head_cycle;
1177         int             head_bytes;
1178
1179         xlog_crack_grant_head(head, &head_cycle, &head_bytes);
1180         xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_bytes);
1181         tail_bytes = BBTOB(tail_bytes);
1182         if (tail_cycle == head_cycle && head_bytes >= tail_bytes)
1183                 free_bytes = log->l_logsize - (head_bytes - tail_bytes);
1184         else if (tail_cycle + 1 < head_cycle)
1185                 return 0;
1186         else if (tail_cycle < head_cycle) {
1187                 ASSERT(tail_cycle == (head_cycle - 1));
1188                 free_bytes = tail_bytes - head_bytes;
1189         } else {
1190                 /*
1191                  * The reservation head is behind the tail.
1192                  * In this case we just want to return the size of the
1193                  * log as the amount of space left.
1194                  */
1195                 xfs_alert(log->l_mp, "xlog_space_left: head behind tail");
1196                 xfs_alert(log->l_mp,
1197                           "  tail_cycle = %d, tail_bytes = %d",
1198                           tail_cycle, tail_bytes);
1199                 xfs_alert(log->l_mp,
1200                           "  GH   cycle = %d, GH   bytes = %d",
1201                           head_cycle, head_bytes);
1202                 ASSERT(0);
1203                 free_bytes = log->l_logsize;
1204         }
1205         return free_bytes;
1206 }
1207
1208
1209 static void
1210 xlog_ioend_work(
1211         struct work_struct      *work)
1212 {
1213         struct xlog_in_core     *iclog =
1214                 container_of(work, struct xlog_in_core, ic_end_io_work);
1215         struct xlog             *log = iclog->ic_log;
1216         bool                    aborted = false;
1217         int                     error;
1218
1219         error = blk_status_to_errno(iclog->ic_bio.bi_status);
1220 #ifdef DEBUG
1221         /* treat writes with injected CRC errors as failed */
1222         if (iclog->ic_fail_crc)
1223                 error = -EIO;
1224 #endif
1225
1226         /*
1227          * Race to shutdown the filesystem if we see an error.
1228          */
1229         if (XFS_TEST_ERROR(error, log->l_mp, XFS_ERRTAG_IODONE_IOERR)) {
1230                 xfs_alert(log->l_mp, "log I/O error %d", error);
1231                 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
1232                 /*
1233                  * This flag will be propagated to the trans-committed
1234                  * callback routines to let them know that the log-commit
1235                  * didn't succeed.
1236                  */
1237                 aborted = true;
1238         } else if (iclog->ic_state & XLOG_STATE_IOERROR) {
1239                 aborted = true;
1240         }
1241
1242         xlog_state_done_syncing(iclog, aborted);
1243         bio_uninit(&iclog->ic_bio);
1244
1245         /*
1246          * Drop the lock to signal that we are done. Nothing references the
1247          * iclog after this, so an unmount waiting on this lock can now tear it
1248          * down safely. As such, it is unsafe to reference the iclog after the
1249          * unlock as we could race with it being freed.
1250          */
1251         up(&iclog->ic_sema);
1252 }
1253
1254 /*
1255  * Return size of each in-core log record buffer.
1256  *
1257  * All machines get 8 x 32kB buffers by default, unless tuned otherwise.
1258  *
1259  * If the filesystem blocksize is too large, we may need to choose a
1260  * larger size since the directory code currently logs entire blocks.
1261  */
1262 STATIC void
1263 xlog_get_iclog_buffer_size(
1264         struct xfs_mount        *mp,
1265         struct xlog             *log)
1266 {
1267         if (mp->m_logbufs <= 0)
1268                 mp->m_logbufs = XLOG_MAX_ICLOGS;
1269         if (mp->m_logbsize <= 0)
1270                 mp->m_logbsize = XLOG_BIG_RECORD_BSIZE;
1271
1272         log->l_iclog_bufs = mp->m_logbufs;
1273         log->l_iclog_size = mp->m_logbsize;
1274
1275         /*
1276          * # headers = size / 32k - one header holds cycles from 32k of data.
1277          */
1278         log->l_iclog_heads =
1279                 DIV_ROUND_UP(mp->m_logbsize, XLOG_HEADER_CYCLE_SIZE);
1280         log->l_iclog_hsize = log->l_iclog_heads << BBSHIFT;
1281 }
1282
1283 void
1284 xfs_log_work_queue(
1285         struct xfs_mount        *mp)
1286 {
1287         queue_delayed_work(mp->m_sync_workqueue, &mp->m_log->l_work,
1288                                 msecs_to_jiffies(xfs_syncd_centisecs * 10));
1289 }
1290
1291 /*
1292  * Every sync period we need to unpin all items in the AIL and push them to
1293  * disk. If there is nothing dirty, then we might need to cover the log to
1294  * indicate that the filesystem is idle.
1295  */
1296 static void
1297 xfs_log_worker(
1298         struct work_struct      *work)
1299 {
1300         struct xlog             *log = container_of(to_delayed_work(work),
1301                                                 struct xlog, l_work);
1302         struct xfs_mount        *mp = log->l_mp;
1303
1304         /* dgc: errors ignored - not fatal and nowhere to report them */
1305         if (xfs_log_need_covered(mp)) {
1306                 /*
1307                  * Dump a transaction into the log that contains no real change.
1308                  * This is needed to stamp the current tail LSN into the log
1309                  * during the covering operation.
1310                  *
1311                  * We cannot use an inode here for this - that will push dirty
1312                  * state back up into the VFS and then periodic inode flushing
1313                  * will prevent log covering from making progress. Hence we
1314                  * synchronously log the superblock instead to ensure the
1315                  * superblock is immediately unpinned and can be written back.
1316                  */
1317                 xfs_sync_sb(mp, true);
1318         } else
1319                 xfs_log_force(mp, 0);
1320
1321         /* start pushing all the metadata that is currently dirty */
1322         xfs_ail_push_all(mp->m_ail);
1323
1324         /* queue us up again */
1325         xfs_log_work_queue(mp);
1326 }
1327
1328 /*
1329  * This routine initializes some of the log structure for a given mount point.
1330  * Its primary purpose is to fill in enough, so recovery can occur.  However,
1331  * some other stuff may be filled in too.
1332  */
1333 STATIC struct xlog *
1334 xlog_alloc_log(
1335         struct xfs_mount        *mp,
1336         struct xfs_buftarg      *log_target,
1337         xfs_daddr_t             blk_offset,
1338         int                     num_bblks)
1339 {
1340         struct xlog             *log;
1341         xlog_rec_header_t       *head;
1342         xlog_in_core_t          **iclogp;
1343         xlog_in_core_t          *iclog, *prev_iclog=NULL;
1344         int                     i;
1345         int                     error = -ENOMEM;
1346         uint                    log2_size = 0;
1347
1348         log = kmem_zalloc(sizeof(struct xlog), KM_MAYFAIL);
1349         if (!log) {
1350                 xfs_warn(mp, "Log allocation failed: No memory!");
1351                 goto out;
1352         }
1353
1354         log->l_mp          = mp;
1355         log->l_targ        = log_target;
1356         log->l_logsize     = BBTOB(num_bblks);
1357         log->l_logBBstart  = blk_offset;
1358         log->l_logBBsize   = num_bblks;
1359         log->l_covered_state = XLOG_STATE_COVER_IDLE;
1360         log->l_flags       |= XLOG_ACTIVE_RECOVERY;
1361         INIT_DELAYED_WORK(&log->l_work, xfs_log_worker);
1362
1363         log->l_prev_block  = -1;
1364         /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
1365         xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0);
1366         xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
1367         log->l_curr_cycle  = 1;     /* 0 is bad since this is initial value */
1368
1369         xlog_grant_head_init(&log->l_reserve_head);
1370         xlog_grant_head_init(&log->l_write_head);
1371
1372         error = -EFSCORRUPTED;
1373         if (xfs_sb_version_hassector(&mp->m_sb)) {
1374                 log2_size = mp->m_sb.sb_logsectlog;
1375                 if (log2_size < BBSHIFT) {
1376                         xfs_warn(mp, "Log sector size too small (0x%x < 0x%x)",
1377                                 log2_size, BBSHIFT);
1378                         goto out_free_log;
1379                 }
1380
1381                 log2_size -= BBSHIFT;
1382                 if (log2_size > mp->m_sectbb_log) {
1383                         xfs_warn(mp, "Log sector size too large (0x%x > 0x%x)",
1384                                 log2_size, mp->m_sectbb_log);
1385                         goto out_free_log;
1386                 }
1387
1388                 /* for larger sector sizes, must have v2 or external log */
1389                 if (log2_size && log->l_logBBstart > 0 &&
1390                             !xfs_sb_version_haslogv2(&mp->m_sb)) {
1391                         xfs_warn(mp,
1392                 "log sector size (0x%x) invalid for configuration.",
1393                                 log2_size);
1394                         goto out_free_log;
1395                 }
1396         }
1397         log->l_sectBBsize = 1 << log2_size;
1398
1399         xlog_get_iclog_buffer_size(mp, log);
1400
1401         spin_lock_init(&log->l_icloglock);
1402         init_waitqueue_head(&log->l_flush_wait);
1403
1404         iclogp = &log->l_iclog;
1405         /*
1406          * The amount of memory to allocate for the iclog structure is
1407          * rather funky due to the way the structure is defined.  It is
1408          * done this way so that we can use different sizes for machines
1409          * with different amounts of memory.  See the definition of
1410          * xlog_in_core_t in xfs_log_priv.h for details.
1411          */
1412         ASSERT(log->l_iclog_size >= 4096);
1413         for (i = 0; i < log->l_iclog_bufs; i++) {
1414                 size_t bvec_size = howmany(log->l_iclog_size, PAGE_SIZE);
1415
1416                 iclog = kmem_zalloc(sizeof(*iclog) + bvec_size, KM_MAYFAIL);
1417                 if (!iclog)
1418                         goto out_free_iclog;
1419
1420                 *iclogp = iclog;
1421                 iclog->ic_prev = prev_iclog;
1422                 prev_iclog = iclog;
1423
1424                 iclog->ic_data = kmem_alloc_large(log->l_iclog_size,
1425                                 KM_MAYFAIL);
1426                 if (!iclog->ic_data)
1427                         goto out_free_iclog;
1428 #ifdef DEBUG
1429                 log->l_iclog_bak[i] = &iclog->ic_header;
1430 #endif
1431                 head = &iclog->ic_header;
1432                 memset(head, 0, sizeof(xlog_rec_header_t));
1433                 head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1434                 head->h_version = cpu_to_be32(
1435                         xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? 2 : 1);
1436                 head->h_size = cpu_to_be32(log->l_iclog_size);
1437                 /* new fields */
1438                 head->h_fmt = cpu_to_be32(XLOG_FMT);
1439                 memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));
1440
1441                 iclog->ic_size = log->l_iclog_size - log->l_iclog_hsize;
1442                 iclog->ic_state = XLOG_STATE_ACTIVE;
1443                 iclog->ic_log = log;
1444                 atomic_set(&iclog->ic_refcnt, 0);
1445                 spin_lock_init(&iclog->ic_callback_lock);
1446                 INIT_LIST_HEAD(&iclog->ic_callbacks);
1447                 iclog->ic_datap = (char *)iclog->ic_data + log->l_iclog_hsize;
1448
1449                 init_waitqueue_head(&iclog->ic_force_wait);
1450                 init_waitqueue_head(&iclog->ic_write_wait);
1451                 INIT_WORK(&iclog->ic_end_io_work, xlog_ioend_work);
1452                 sema_init(&iclog->ic_sema, 1);
1453
1454                 iclogp = &iclog->ic_next;
1455         }
1456         *iclogp = log->l_iclog;                 /* complete ring */
1457         log->l_iclog->ic_prev = prev_iclog;     /* re-write 1st prev ptr */
1458
1459         log->l_ioend_workqueue = alloc_workqueue("xfs-log/%s",
1460                         WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_HIGHPRI, 0,
1461                         mp->m_fsname);
1462         if (!log->l_ioend_workqueue)
1463                 goto out_free_iclog;
1464
1465         error = xlog_cil_init(log);
1466         if (error)
1467                 goto out_destroy_workqueue;
1468         return log;
1469
1470 out_destroy_workqueue:
1471         destroy_workqueue(log->l_ioend_workqueue);
1472 out_free_iclog:
1473         for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
1474                 prev_iclog = iclog->ic_next;
1475                 kmem_free(iclog->ic_data);
1476                 kmem_free(iclog);
1477         }
1478 out_free_log:
1479         kmem_free(log);
1480 out:
1481         return ERR_PTR(error);
1482 }       /* xlog_alloc_log */
1483
1484
1485 /*
1486  * Write out the commit record of a transaction associated with the given
1487  * ticket.  Return the lsn of the commit record.
1488  */
1489 STATIC int
1490 xlog_commit_record(
1491         struct xlog             *log,
1492         struct xlog_ticket      *ticket,
1493         struct xlog_in_core     **iclog,
1494         xfs_lsn_t               *commitlsnp)
1495 {
1496         struct xfs_mount *mp = log->l_mp;
1497         int     error;
1498         struct xfs_log_iovec reg = {
1499                 .i_addr = NULL,
1500                 .i_len = 0,
1501                 .i_type = XLOG_REG_TYPE_COMMIT,
1502         };
1503         struct xfs_log_vec vec = {
1504                 .lv_niovecs = 1,
1505                 .lv_iovecp = &reg,
1506         };
1507
1508         ASSERT_ALWAYS(iclog);
1509         error = xlog_write(log, &vec, ticket, commitlsnp, iclog,
1510                                         XLOG_COMMIT_TRANS);
1511         if (error)
1512                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
1513         return error;
1514 }
1515
1516 /*
1517  * Push on the buffer cache code if we ever use more than 75% of the on-disk
1518  * log space.  This code pushes on the lsn which would supposedly free up
1519  * the 25% which we want to leave free.  We may need to adopt a policy which
1520  * pushes on an lsn which is further along in the log once we reach the high
1521  * water mark.  In this manner, we would be creating a low water mark.
1522  */
1523 STATIC void
1524 xlog_grant_push_ail(
1525         struct xlog     *log,
1526         int             need_bytes)
1527 {
1528         xfs_lsn_t       threshold_lsn = 0;
1529         xfs_lsn_t       last_sync_lsn;
1530         int             free_blocks;
1531         int             free_bytes;
1532         int             threshold_block;
1533         int             threshold_cycle;
1534         int             free_threshold;
1535
1536         ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
1537
1538         free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1539         free_blocks = BTOBBT(free_bytes);
1540
1541         /*
1542          * Set the threshold for the minimum number of free blocks in the
1543          * log to the maximum of what the caller needs, one quarter of the
1544          * log, and 256 blocks.
1545          */
1546         free_threshold = BTOBB(need_bytes);
1547         free_threshold = max(free_threshold, (log->l_logBBsize >> 2));
1548         free_threshold = max(free_threshold, 256);
1549         if (free_blocks >= free_threshold)
1550                 return;
1551
1552         xlog_crack_atomic_lsn(&log->l_tail_lsn, &threshold_cycle,
1553                                                 &threshold_block);
1554         threshold_block += free_threshold;
1555         if (threshold_block >= log->l_logBBsize) {
1556                 threshold_block -= log->l_logBBsize;
1557                 threshold_cycle += 1;
1558         }
1559         threshold_lsn = xlog_assign_lsn(threshold_cycle,
1560                                         threshold_block);
1561         /*
1562          * Don't pass in an lsn greater than the lsn of the last
1563          * log record known to be on disk. Use a snapshot of the last sync lsn
1564          * so that it doesn't change between the compare and the set.
1565          */
1566         last_sync_lsn = atomic64_read(&log->l_last_sync_lsn);
1567         if (XFS_LSN_CMP(threshold_lsn, last_sync_lsn) > 0)
1568                 threshold_lsn = last_sync_lsn;
1569
1570         /*
1571          * Get the transaction layer to kick the dirty buffers out to
1572          * disk asynchronously. No point in trying to do this if
1573          * the filesystem is shutting down.
1574          */
1575         if (!XLOG_FORCED_SHUTDOWN(log))
1576                 xfs_ail_push(log->l_ailp, threshold_lsn);
1577 }
1578
1579 /*
1580  * Stamp cycle number in every block
1581  */
1582 STATIC void
1583 xlog_pack_data(
1584         struct xlog             *log,
1585         struct xlog_in_core     *iclog,
1586         int                     roundoff)
1587 {
1588         int                     i, j, k;
1589         int                     size = iclog->ic_offset + roundoff;
1590         __be32                  cycle_lsn;
1591         char                    *dp;
1592
1593         cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn);
1594
1595         dp = iclog->ic_datap;
1596         for (i = 0; i < BTOBB(size); i++) {
1597                 if (i >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE))
1598                         break;
1599                 iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp;
1600                 *(__be32 *)dp = cycle_lsn;
1601                 dp += BBSIZE;
1602         }
1603
1604         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1605                 xlog_in_core_2_t *xhdr = iclog->ic_data;
1606
1607                 for ( ; i < BTOBB(size); i++) {
1608                         j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1609                         k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1610                         xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp;
1611                         *(__be32 *)dp = cycle_lsn;
1612                         dp += BBSIZE;
1613                 }
1614
1615                 for (i = 1; i < log->l_iclog_heads; i++)
1616                         xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
1617         }
1618 }
1619
1620 /*
1621  * Calculate the checksum for a log buffer.
1622  *
1623  * This is a little more complicated than it should be because the various
1624  * headers and the actual data are non-contiguous.
1625  */
1626 __le32
1627 xlog_cksum(
1628         struct xlog             *log,
1629         struct xlog_rec_header  *rhead,
1630         char                    *dp,
1631         int                     size)
1632 {
1633         uint32_t                crc;
1634
1635         /* first generate the crc for the record header ... */
1636         crc = xfs_start_cksum_update((char *)rhead,
1637                               sizeof(struct xlog_rec_header),
1638                               offsetof(struct xlog_rec_header, h_crc));
1639
1640         /* ... then for additional cycle data for v2 logs ... */
1641         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1642                 union xlog_in_core2 *xhdr = (union xlog_in_core2 *)rhead;
1643                 int             i;
1644                 int             xheads;
1645
1646                 xheads = size / XLOG_HEADER_CYCLE_SIZE;
1647                 if (size % XLOG_HEADER_CYCLE_SIZE)
1648                         xheads++;
1649
1650                 for (i = 1; i < xheads; i++) {
1651                         crc = crc32c(crc, &xhdr[i].hic_xheader,
1652                                      sizeof(struct xlog_rec_ext_header));
1653                 }
1654         }
1655
1656         /* ... and finally for the payload */
1657         crc = crc32c(crc, dp, size);
1658
1659         return xfs_end_cksum(crc);
1660 }
1661
1662 static void
1663 xlog_bio_end_io(
1664         struct bio              *bio)
1665 {
1666         struct xlog_in_core     *iclog = bio->bi_private;
1667
1668         queue_work(iclog->ic_log->l_ioend_workqueue,
1669                    &iclog->ic_end_io_work);
1670 }
1671
1672 static void
1673 xlog_map_iclog_data(
1674         struct bio              *bio,
1675         void                    *data,
1676         size_t                  count)
1677 {
1678         do {
1679                 struct page     *page = kmem_to_page(data);
1680                 unsigned int    off = offset_in_page(data);
1681                 size_t          len = min_t(size_t, count, PAGE_SIZE - off);
1682
1683                 WARN_ON_ONCE(bio_add_page(bio, page, len, off) != len);
1684
1685                 data += len;
1686                 count -= len;
1687         } while (count);
1688 }
1689
1690 STATIC void
1691 xlog_write_iclog(
1692         struct xlog             *log,
1693         struct xlog_in_core     *iclog,
1694         uint64_t                bno,
1695         unsigned int            count,
1696         bool                    need_flush)
1697 {
1698         ASSERT(bno < log->l_logBBsize);
1699
1700         /*
1701          * We lock the iclogbufs here so that we can serialise against I/O
1702          * completion during unmount.  We might be processing a shutdown
1703          * triggered during unmount, and that can occur asynchronously to the
1704          * unmount thread, and hence we need to ensure that completes before
1705          * tearing down the iclogbufs.  Hence we need to hold the buffer lock
1706          * across the log IO to archieve that.
1707          */
1708         down(&iclog->ic_sema);
1709         if (unlikely(iclog->ic_state & XLOG_STATE_IOERROR)) {
1710                 /*
1711                  * It would seem logical to return EIO here, but we rely on
1712                  * the log state machine to propagate I/O errors instead of
1713                  * doing it here.  We kick of the state machine and unlock
1714                  * the buffer manually, the code needs to be kept in sync
1715                  * with the I/O completion path.
1716                  */
1717                 xlog_state_done_syncing(iclog, XFS_LI_ABORTED);
1718                 up(&iclog->ic_sema);
1719                 return;
1720         }
1721
1722         iclog->ic_io_size = count;
1723
1724         bio_init(&iclog->ic_bio, iclog->ic_bvec, howmany(count, PAGE_SIZE));
1725         bio_set_dev(&iclog->ic_bio, log->l_targ->bt_bdev);
1726         iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart + bno;
1727         iclog->ic_bio.bi_end_io = xlog_bio_end_io;
1728         iclog->ic_bio.bi_private = iclog;
1729         iclog->ic_bio.bi_opf = REQ_OP_WRITE | REQ_META | REQ_SYNC | REQ_FUA;
1730         if (need_flush)
1731                 iclog->ic_bio.bi_opf |= REQ_PREFLUSH;
1732
1733         xlog_map_iclog_data(&iclog->ic_bio, iclog->ic_data, iclog->ic_io_size);
1734         if (is_vmalloc_addr(iclog->ic_data))
1735                 flush_kernel_vmap_range(iclog->ic_data, iclog->ic_io_size);
1736
1737         /*
1738          * If this log buffer would straddle the end of the log we will have
1739          * to split it up into two bios, so that we can continue at the start.
1740          */
1741         if (bno + BTOBB(count) > log->l_logBBsize) {
1742                 struct bio *split;
1743
1744                 split = bio_split(&iclog->ic_bio, log->l_logBBsize - bno,
1745                                   GFP_NOIO, &fs_bio_set);
1746                 bio_chain(split, &iclog->ic_bio);
1747                 submit_bio(split);
1748
1749                 /* restart at logical offset zero for the remainder */
1750                 iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart;
1751         }
1752
1753         submit_bio(&iclog->ic_bio);
1754 }
1755
1756 /*
1757  * We need to bump cycle number for the part of the iclog that is
1758  * written to the start of the log. Watch out for the header magic
1759  * number case, though.
1760  */
1761 static void
1762 xlog_split_iclog(
1763         struct xlog             *log,
1764         void                    *data,
1765         uint64_t                bno,
1766         unsigned int            count)
1767 {
1768         unsigned int            split_offset = BBTOB(log->l_logBBsize - bno);
1769         unsigned int            i;
1770
1771         for (i = split_offset; i < count; i += BBSIZE) {
1772                 uint32_t cycle = get_unaligned_be32(data + i);
1773
1774                 if (++cycle == XLOG_HEADER_MAGIC_NUM)
1775                         cycle++;
1776                 put_unaligned_be32(cycle, data + i);
1777         }
1778 }
1779
1780 static int
1781 xlog_calc_iclog_size(
1782         struct xlog             *log,
1783         struct xlog_in_core     *iclog,
1784         uint32_t                *roundoff)
1785 {
1786         uint32_t                count_init, count;
1787         bool                    use_lsunit;
1788
1789         use_lsunit = xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
1790                         log->l_mp->m_sb.sb_logsunit > 1;
1791
1792         /* Add for LR header */
1793         count_init = log->l_iclog_hsize + iclog->ic_offset;
1794
1795         /* Round out the log write size */
1796         if (use_lsunit) {
1797                 /* we have a v2 stripe unit to use */
1798                 count = XLOG_LSUNITTOB(log, XLOG_BTOLSUNIT(log, count_init));
1799         } else {
1800                 count = BBTOB(BTOBB(count_init));
1801         }
1802
1803         ASSERT(count >= count_init);
1804         *roundoff = count - count_init;
1805
1806         if (use_lsunit)
1807                 ASSERT(*roundoff < log->l_mp->m_sb.sb_logsunit);
1808         else
1809                 ASSERT(*roundoff < BBTOB(1));
1810         return count;
1811 }
1812
1813 /*
1814  * Flush out the in-core log (iclog) to the on-disk log in an asynchronous
1815  * fashion.  Previously, we should have moved the current iclog
1816  * ptr in the log to point to the next available iclog.  This allows further
1817  * write to continue while this code syncs out an iclog ready to go.
1818  * Before an in-core log can be written out, the data section must be scanned
1819  * to save away the 1st word of each BBSIZE block into the header.  We replace
1820  * it with the current cycle count.  Each BBSIZE block is tagged with the
1821  * cycle count because there in an implicit assumption that drives will
1822  * guarantee that entire 512 byte blocks get written at once.  In other words,
1823  * we can't have part of a 512 byte block written and part not written.  By
1824  * tagging each block, we will know which blocks are valid when recovering
1825  * after an unclean shutdown.
1826  *
1827  * This routine is single threaded on the iclog.  No other thread can be in
1828  * this routine with the same iclog.  Changing contents of iclog can there-
1829  * fore be done without grabbing the state machine lock.  Updating the global
1830  * log will require grabbing the lock though.
1831  *
1832  * The entire log manager uses a logical block numbering scheme.  Only
1833  * xlog_write_iclog knows about the fact that the log may not start with
1834  * block zero on a given device.
1835  */
1836 STATIC void
1837 xlog_sync(
1838         struct xlog             *log,
1839         struct xlog_in_core     *iclog)
1840 {
1841         unsigned int            count;          /* byte count of bwrite */
1842         unsigned int            roundoff;       /* roundoff to BB or stripe */
1843         uint64_t                bno;
1844         unsigned int            size;
1845         bool                    need_flush = true, split = false;
1846
1847         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
1848
1849         count = xlog_calc_iclog_size(log, iclog, &roundoff);
1850
1851         /* move grant heads by roundoff in sync */
1852         xlog_grant_add_space(log, &log->l_reserve_head.grant, roundoff);
1853         xlog_grant_add_space(log, &log->l_write_head.grant, roundoff);
1854
1855         /* put cycle number in every block */
1856         xlog_pack_data(log, iclog, roundoff);
1857
1858         /* real byte length */
1859         size = iclog->ic_offset;
1860         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb))
1861                 size += roundoff;
1862         iclog->ic_header.h_len = cpu_to_be32(size);
1863
1864         XFS_STATS_INC(log->l_mp, xs_log_writes);
1865         XFS_STATS_ADD(log->l_mp, xs_log_blocks, BTOBB(count));
1866
1867         bno = BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn));
1868
1869         /* Do we need to split this write into 2 parts? */
1870         if (bno + BTOBB(count) > log->l_logBBsize) {
1871                 xlog_split_iclog(log, &iclog->ic_header, bno, count);
1872                 split = true;
1873         }
1874
1875         /* calculcate the checksum */
1876         iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header,
1877                                             iclog->ic_datap, size);
1878         /*
1879          * Intentionally corrupt the log record CRC based on the error injection
1880          * frequency, if defined. This facilitates testing log recovery in the
1881          * event of torn writes. Hence, set the IOABORT state to abort the log
1882          * write on I/O completion and shutdown the fs. The subsequent mount
1883          * detects the bad CRC and attempts to recover.
1884          */
1885 #ifdef DEBUG
1886         if (XFS_TEST_ERROR(false, log->l_mp, XFS_ERRTAG_LOG_BAD_CRC)) {
1887                 iclog->ic_header.h_crc &= cpu_to_le32(0xAAAAAAAA);
1888                 iclog->ic_fail_crc = true;
1889                 xfs_warn(log->l_mp,
1890         "Intentionally corrupted log record at LSN 0x%llx. Shutdown imminent.",
1891                          be64_to_cpu(iclog->ic_header.h_lsn));
1892         }
1893 #endif
1894
1895         /*
1896          * Flush the data device before flushing the log to make sure all meta
1897          * data written back from the AIL actually made it to disk before
1898          * stamping the new log tail LSN into the log buffer.  For an external
1899          * log we need to issue the flush explicitly, and unfortunately
1900          * synchronously here; for an internal log we can simply use the block
1901          * layer state machine for preflushes.
1902          */
1903         if (log->l_targ != log->l_mp->m_ddev_targp || split) {
1904                 xfs_blkdev_issue_flush(log->l_mp->m_ddev_targp);
1905                 need_flush = false;
1906         }
1907
1908         xlog_verify_iclog(log, iclog, count);
1909         xlog_write_iclog(log, iclog, bno, count, need_flush);
1910 }
1911
1912 /*
1913  * Deallocate a log structure
1914  */
1915 STATIC void
1916 xlog_dealloc_log(
1917         struct xlog     *log)
1918 {
1919         xlog_in_core_t  *iclog, *next_iclog;
1920         int             i;
1921
1922         xlog_cil_destroy(log);
1923
1924         /*
1925          * Cycle all the iclogbuf locks to make sure all log IO completion
1926          * is done before we tear down these buffers.
1927          */
1928         iclog = log->l_iclog;
1929         for (i = 0; i < log->l_iclog_bufs; i++) {
1930                 down(&iclog->ic_sema);
1931                 up(&iclog->ic_sema);
1932                 iclog = iclog->ic_next;
1933         }
1934
1935         iclog = log->l_iclog;
1936         for (i = 0; i < log->l_iclog_bufs; i++) {
1937                 next_iclog = iclog->ic_next;
1938                 kmem_free(iclog->ic_data);
1939                 kmem_free(iclog);
1940                 iclog = next_iclog;
1941         }
1942
1943         log->l_mp->m_log = NULL;
1944         destroy_workqueue(log->l_ioend_workqueue);
1945         kmem_free(log);
1946 }       /* xlog_dealloc_log */
1947
1948 /*
1949  * Update counters atomically now that memcpy is done.
1950  */
1951 /* ARGSUSED */
1952 static inline void
1953 xlog_state_finish_copy(
1954         struct xlog             *log,
1955         struct xlog_in_core     *iclog,
1956         int                     record_cnt,
1957         int                     copy_bytes)
1958 {
1959         spin_lock(&log->l_icloglock);
1960
1961         be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
1962         iclog->ic_offset += copy_bytes;
1963
1964         spin_unlock(&log->l_icloglock);
1965 }       /* xlog_state_finish_copy */
1966
1967
1968
1969
1970 /*
1971  * print out info relating to regions written which consume
1972  * the reservation
1973  */
1974 void
1975 xlog_print_tic_res(
1976         struct xfs_mount        *mp,
1977         struct xlog_ticket      *ticket)
1978 {
1979         uint i;
1980         uint ophdr_spc = ticket->t_res_num_ophdrs * (uint)sizeof(xlog_op_header_t);
1981
1982         /* match with XLOG_REG_TYPE_* in xfs_log.h */
1983 #define REG_TYPE_STR(type, str) [XLOG_REG_TYPE_##type] = str
1984         static char *res_type_str[] = {
1985             REG_TYPE_STR(BFORMAT, "bformat"),
1986             REG_TYPE_STR(BCHUNK, "bchunk"),
1987             REG_TYPE_STR(EFI_FORMAT, "efi_format"),
1988             REG_TYPE_STR(EFD_FORMAT, "efd_format"),
1989             REG_TYPE_STR(IFORMAT, "iformat"),
1990             REG_TYPE_STR(ICORE, "icore"),
1991             REG_TYPE_STR(IEXT, "iext"),
1992             REG_TYPE_STR(IBROOT, "ibroot"),
1993             REG_TYPE_STR(ILOCAL, "ilocal"),
1994             REG_TYPE_STR(IATTR_EXT, "iattr_ext"),
1995             REG_TYPE_STR(IATTR_BROOT, "iattr_broot"),
1996             REG_TYPE_STR(IATTR_LOCAL, "iattr_local"),
1997             REG_TYPE_STR(QFORMAT, "qformat"),
1998             REG_TYPE_STR(DQUOT, "dquot"),
1999             REG_TYPE_STR(QUOTAOFF, "quotaoff"),
2000             REG_TYPE_STR(LRHEADER, "LR header"),
2001             REG_TYPE_STR(UNMOUNT, "unmount"),
2002             REG_TYPE_STR(COMMIT, "commit"),
2003             REG_TYPE_STR(TRANSHDR, "trans header"),
2004             REG_TYPE_STR(ICREATE, "inode create"),
2005             REG_TYPE_STR(RUI_FORMAT, "rui_format"),
2006             REG_TYPE_STR(RUD_FORMAT, "rud_format"),
2007             REG_TYPE_STR(CUI_FORMAT, "cui_format"),
2008             REG_TYPE_STR(CUD_FORMAT, "cud_format"),
2009             REG_TYPE_STR(BUI_FORMAT, "bui_format"),
2010             REG_TYPE_STR(BUD_FORMAT, "bud_format"),
2011         };
2012         BUILD_BUG_ON(ARRAY_SIZE(res_type_str) != XLOG_REG_TYPE_MAX + 1);
2013 #undef REG_TYPE_STR
2014
2015         xfs_warn(mp, "ticket reservation summary:");
2016         xfs_warn(mp, "  unit res    = %d bytes",
2017                  ticket->t_unit_res);
2018         xfs_warn(mp, "  current res = %d bytes",
2019                  ticket->t_curr_res);
2020         xfs_warn(mp, "  total reg   = %u bytes (o/flow = %u bytes)",
2021                  ticket->t_res_arr_sum, ticket->t_res_o_flow);
2022         xfs_warn(mp, "  ophdrs      = %u (ophdr space = %u bytes)",
2023                  ticket->t_res_num_ophdrs, ophdr_spc);
2024         xfs_warn(mp, "  ophdr + reg = %u bytes",
2025                  ticket->t_res_arr_sum + ticket->t_res_o_flow + ophdr_spc);
2026         xfs_warn(mp, "  num regions = %u",
2027                  ticket->t_res_num);
2028
2029         for (i = 0; i < ticket->t_res_num; i++) {
2030                 uint r_type = ticket->t_res_arr[i].r_type;
2031                 xfs_warn(mp, "region[%u]: %s - %u bytes", i,
2032                             ((r_type <= 0 || r_type > XLOG_REG_TYPE_MAX) ?
2033                             "bad-rtype" : res_type_str[r_type]),
2034                             ticket->t_res_arr[i].r_len);
2035         }
2036 }
2037
2038 /*
2039  * Print a summary of the transaction.
2040  */
2041 void
2042 xlog_print_trans(
2043         struct xfs_trans        *tp)
2044 {
2045         struct xfs_mount        *mp = tp->t_mountp;
2046         struct xfs_log_item     *lip;
2047
2048         /* dump core transaction and ticket info */
2049         xfs_warn(mp, "transaction summary:");
2050         xfs_warn(mp, "  log res   = %d", tp->t_log_res);
2051         xfs_warn(mp, "  log count = %d", tp->t_log_count);
2052         xfs_warn(mp, "  flags     = 0x%x", tp->t_flags);
2053
2054         xlog_print_tic_res(mp, tp->t_ticket);
2055
2056         /* dump each log item */
2057         list_for_each_entry(lip, &tp->t_items, li_trans) {
2058                 struct xfs_log_vec      *lv = lip->li_lv;
2059                 struct xfs_log_iovec    *vec;
2060                 int                     i;
2061
2062                 xfs_warn(mp, "log item: ");
2063                 xfs_warn(mp, "  type    = 0x%x", lip->li_type);
2064                 xfs_warn(mp, "  flags   = 0x%lx", lip->li_flags);
2065                 if (!lv)
2066                         continue;
2067                 xfs_warn(mp, "  niovecs = %d", lv->lv_niovecs);
2068                 xfs_warn(mp, "  size    = %d", lv->lv_size);
2069                 xfs_warn(mp, "  bytes   = %d", lv->lv_bytes);
2070                 xfs_warn(mp, "  buf len = %d", lv->lv_buf_len);
2071
2072                 /* dump each iovec for the log item */
2073                 vec = lv->lv_iovecp;
2074                 for (i = 0; i < lv->lv_niovecs; i++) {
2075                         int dumplen = min(vec->i_len, 32);
2076
2077                         xfs_warn(mp, "  iovec[%d]", i);
2078                         xfs_warn(mp, "    type  = 0x%x", vec->i_type);
2079                         xfs_warn(mp, "    len   = %d", vec->i_len);
2080                         xfs_warn(mp, "    first %d bytes of iovec[%d]:", dumplen, i);
2081                         xfs_hex_dump(vec->i_addr, dumplen);
2082
2083                         vec++;
2084                 }
2085         }
2086 }
2087
2088 /*
2089  * Calculate the potential space needed by the log vector.  Each region gets
2090  * its own xlog_op_header_t and may need to be double word aligned.
2091  */
2092 static int
2093 xlog_write_calc_vec_length(
2094         struct xlog_ticket      *ticket,
2095         struct xfs_log_vec      *log_vector)
2096 {
2097         struct xfs_log_vec      *lv;
2098         int                     headers = 0;
2099         int                     len = 0;
2100         int                     i;
2101
2102         /* acct for start rec of xact */
2103         if (ticket->t_flags & XLOG_TIC_INITED)
2104                 headers++;
2105
2106         for (lv = log_vector; lv; lv = lv->lv_next) {
2107                 /* we don't write ordered log vectors */
2108                 if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED)
2109                         continue;
2110
2111                 headers += lv->lv_niovecs;
2112
2113                 for (i = 0; i < lv->lv_niovecs; i++) {
2114                         struct xfs_log_iovec    *vecp = &lv->lv_iovecp[i];
2115
2116                         len += vecp->i_len;
2117                         xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type);
2118                 }
2119         }
2120
2121         ticket->t_res_num_ophdrs += headers;
2122         len += headers * sizeof(struct xlog_op_header);
2123
2124         return len;
2125 }
2126
2127 /*
2128  * If first write for transaction, insert start record  We can't be trying to
2129  * commit if we are inited.  We can't have any "partial_copy" if we are inited.
2130  */
2131 static int
2132 xlog_write_start_rec(
2133         struct xlog_op_header   *ophdr,
2134         struct xlog_ticket      *ticket)
2135 {
2136         if (!(ticket->t_flags & XLOG_TIC_INITED))
2137                 return 0;
2138
2139         ophdr->oh_tid   = cpu_to_be32(ticket->t_tid);
2140         ophdr->oh_clientid = ticket->t_clientid;
2141         ophdr->oh_len = 0;
2142         ophdr->oh_flags = XLOG_START_TRANS;
2143         ophdr->oh_res2 = 0;
2144
2145         ticket->t_flags &= ~XLOG_TIC_INITED;
2146
2147         return sizeof(struct xlog_op_header);
2148 }
2149
2150 static xlog_op_header_t *
2151 xlog_write_setup_ophdr(
2152         struct xlog             *log,
2153         struct xlog_op_header   *ophdr,
2154         struct xlog_ticket      *ticket,
2155         uint                    flags)
2156 {
2157         ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2158         ophdr->oh_clientid = ticket->t_clientid;
2159         ophdr->oh_res2 = 0;
2160
2161         /* are we copying a commit or unmount record? */
2162         ophdr->oh_flags = flags;
2163
2164         /*
2165          * We've seen logs corrupted with bad transaction client ids.  This
2166          * makes sure that XFS doesn't generate them on.  Turn this into an EIO
2167          * and shut down the filesystem.
2168          */
2169         switch (ophdr->oh_clientid)  {
2170         case XFS_TRANSACTION:
2171         case XFS_VOLUME:
2172         case XFS_LOG:
2173                 break;
2174         default:
2175                 xfs_warn(log->l_mp,
2176                         "Bad XFS transaction clientid 0x%x in ticket "PTR_FMT,
2177                         ophdr->oh_clientid, ticket);
2178                 return NULL;
2179         }
2180
2181         return ophdr;
2182 }
2183
2184 /*
2185  * Set up the parameters of the region copy into the log. This has
2186  * to handle region write split across multiple log buffers - this
2187  * state is kept external to this function so that this code can
2188  * be written in an obvious, self documenting manner.
2189  */
2190 static int
2191 xlog_write_setup_copy(
2192         struct xlog_ticket      *ticket,
2193         struct xlog_op_header   *ophdr,
2194         int                     space_available,
2195         int                     space_required,
2196         int                     *copy_off,
2197         int                     *copy_len,
2198         int                     *last_was_partial_copy,
2199         int                     *bytes_consumed)
2200 {
2201         int                     still_to_copy;
2202
2203         still_to_copy = space_required - *bytes_consumed;
2204         *copy_off = *bytes_consumed;
2205
2206         if (still_to_copy <= space_available) {
2207                 /* write of region completes here */
2208                 *copy_len = still_to_copy;
2209                 ophdr->oh_len = cpu_to_be32(*copy_len);
2210                 if (*last_was_partial_copy)
2211                         ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
2212                 *last_was_partial_copy = 0;
2213                 *bytes_consumed = 0;
2214                 return 0;
2215         }
2216
2217         /* partial write of region, needs extra log op header reservation */
2218         *copy_len = space_available;
2219         ophdr->oh_len = cpu_to_be32(*copy_len);
2220         ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
2221         if (*last_was_partial_copy)
2222                 ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
2223         *bytes_consumed += *copy_len;
2224         (*last_was_partial_copy)++;
2225
2226         /* account for new log op header */
2227         ticket->t_curr_res -= sizeof(struct xlog_op_header);
2228         ticket->t_res_num_ophdrs++;
2229
2230         return sizeof(struct xlog_op_header);
2231 }
2232
2233 static int
2234 xlog_write_copy_finish(
2235         struct xlog             *log,
2236         struct xlog_in_core     *iclog,
2237         uint                    flags,
2238         int                     *record_cnt,
2239         int                     *data_cnt,
2240         int                     *partial_copy,
2241         int                     *partial_copy_len,
2242         int                     log_offset,
2243         struct xlog_in_core     **commit_iclog)
2244 {
2245         if (*partial_copy) {
2246                 /*
2247                  * This iclog has already been marked WANT_SYNC by
2248                  * xlog_state_get_iclog_space.
2249                  */
2250                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2251                 *record_cnt = 0;
2252                 *data_cnt = 0;
2253                 return xlog_state_release_iclog(log, iclog);
2254         }
2255
2256         *partial_copy = 0;
2257         *partial_copy_len = 0;
2258
2259         if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
2260                 /* no more space in this iclog - push it. */
2261                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2262                 *record_cnt = 0;
2263                 *data_cnt = 0;
2264
2265                 spin_lock(&log->l_icloglock);
2266                 xlog_state_want_sync(log, iclog);
2267                 spin_unlock(&log->l_icloglock);
2268
2269                 if (!commit_iclog)
2270                         return xlog_state_release_iclog(log, iclog);
2271                 ASSERT(flags & XLOG_COMMIT_TRANS);
2272                 *commit_iclog = iclog;
2273         }
2274
2275         return 0;
2276 }
2277
2278 /*
2279  * Write some region out to in-core log
2280  *
2281  * This will be called when writing externally provided regions or when
2282  * writing out a commit record for a given transaction.
2283  *
2284  * General algorithm:
2285  *      1. Find total length of this write.  This may include adding to the
2286  *              lengths passed in.
2287  *      2. Check whether we violate the tickets reservation.
2288  *      3. While writing to this iclog
2289  *          A. Reserve as much space in this iclog as can get
2290  *          B. If this is first write, save away start lsn
2291  *          C. While writing this region:
2292  *              1. If first write of transaction, write start record
2293  *              2. Write log operation header (header per region)
2294  *              3. Find out if we can fit entire region into this iclog
2295  *              4. Potentially, verify destination memcpy ptr
2296  *              5. Memcpy (partial) region
2297  *              6. If partial copy, release iclog; otherwise, continue
2298  *                      copying more regions into current iclog
2299  *      4. Mark want sync bit (in simulation mode)
2300  *      5. Release iclog for potential flush to on-disk log.
2301  *
2302  * ERRORS:
2303  * 1.   Panic if reservation is overrun.  This should never happen since
2304  *      reservation amounts are generated internal to the filesystem.
2305  * NOTES:
2306  * 1. Tickets are single threaded data structures.
2307  * 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
2308  *      syncing routine.  When a single log_write region needs to span
2309  *      multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
2310  *      on all log operation writes which don't contain the end of the
2311  *      region.  The XLOG_END_TRANS bit is used for the in-core log
2312  *      operation which contains the end of the continued log_write region.
2313  * 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
2314  *      we don't really know exactly how much space will be used.  As a result,
2315  *      we don't update ic_offset until the end when we know exactly how many
2316  *      bytes have been written out.
2317  */
2318 int
2319 xlog_write(
2320         struct xlog             *log,
2321         struct xfs_log_vec      *log_vector,
2322         struct xlog_ticket      *ticket,
2323         xfs_lsn_t               *start_lsn,
2324         struct xlog_in_core     **commit_iclog,
2325         uint                    flags)
2326 {
2327         struct xlog_in_core     *iclog = NULL;
2328         struct xfs_log_iovec    *vecp;
2329         struct xfs_log_vec      *lv;
2330         int                     len;
2331         int                     index;
2332         int                     partial_copy = 0;
2333         int                     partial_copy_len = 0;
2334         int                     contwr = 0;
2335         int                     record_cnt = 0;
2336         int                     data_cnt = 0;
2337         int                     error;
2338
2339         *start_lsn = 0;
2340
2341         len = xlog_write_calc_vec_length(ticket, log_vector);
2342
2343         /*
2344          * Region headers and bytes are already accounted for.
2345          * We only need to take into account start records and
2346          * split regions in this function.
2347          */
2348         if (ticket->t_flags & XLOG_TIC_INITED)
2349                 ticket->t_curr_res -= sizeof(xlog_op_header_t);
2350
2351         /*
2352          * Commit record headers need to be accounted for. These
2353          * come in as separate writes so are easy to detect.
2354          */
2355         if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS))
2356                 ticket->t_curr_res -= sizeof(xlog_op_header_t);
2357
2358         if (ticket->t_curr_res < 0) {
2359                 xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
2360                      "ctx ticket reservation ran out. Need to up reservation");
2361                 xlog_print_tic_res(log->l_mp, ticket);
2362                 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
2363         }
2364
2365         index = 0;
2366         lv = log_vector;
2367         vecp = lv->lv_iovecp;
2368         while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2369                 void            *ptr;
2370                 int             log_offset;
2371
2372                 error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
2373                                                    &contwr, &log_offset);
2374                 if (error)
2375                         return error;
2376
2377                 ASSERT(log_offset <= iclog->ic_size - 1);
2378                 ptr = iclog->ic_datap + log_offset;
2379
2380                 /* start_lsn is the first lsn written to. That's all we need. */
2381                 if (!*start_lsn)
2382                         *start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2383
2384                 /*
2385                  * This loop writes out as many regions as can fit in the amount
2386                  * of space which was allocated by xlog_state_get_iclog_space().
2387                  */
2388                 while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2389                         struct xfs_log_iovec    *reg;
2390                         struct xlog_op_header   *ophdr;
2391                         int                     start_rec_copy;
2392                         int                     copy_len;
2393                         int                     copy_off;
2394                         bool                    ordered = false;
2395
2396                         /* ordered log vectors have no regions to write */
2397                         if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) {
2398                                 ASSERT(lv->lv_niovecs == 0);
2399                                 ordered = true;
2400                                 goto next_lv;
2401                         }
2402
2403                         reg = &vecp[index];
2404                         ASSERT(reg->i_len % sizeof(int32_t) == 0);
2405                         ASSERT((unsigned long)ptr % sizeof(int32_t) == 0);
2406
2407                         start_rec_copy = xlog_write_start_rec(ptr, ticket);
2408                         if (start_rec_copy) {
2409                                 record_cnt++;
2410                                 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2411                                                    start_rec_copy);
2412                         }
2413
2414                         ophdr = xlog_write_setup_ophdr(log, ptr, ticket, flags);
2415                         if (!ophdr)
2416                                 return -EIO;
2417
2418                         xlog_write_adv_cnt(&ptr, &len, &log_offset,
2419                                            sizeof(struct xlog_op_header));
2420
2421                         len += xlog_write_setup_copy(ticket, ophdr,
2422                                                      iclog->ic_size-log_offset,
2423                                                      reg->i_len,
2424                                                      &copy_off, &copy_len,
2425                                                      &partial_copy,
2426                                                      &partial_copy_len);
2427                         xlog_verify_dest_ptr(log, ptr);
2428
2429                         /*
2430                          * Copy region.
2431                          *
2432                          * Unmount records just log an opheader, so can have
2433                          * empty payloads with no data region to copy. Hence we
2434                          * only copy the payload if the vector says it has data
2435                          * to copy.
2436                          */
2437                         ASSERT(copy_len >= 0);
2438                         if (copy_len > 0) {
2439                                 memcpy(ptr, reg->i_addr + copy_off, copy_len);
2440                                 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2441                                                    copy_len);
2442                         }
2443                         copy_len += start_rec_copy + sizeof(xlog_op_header_t);
2444                         record_cnt++;
2445                         data_cnt += contwr ? copy_len : 0;
2446
2447                         error = xlog_write_copy_finish(log, iclog, flags,
2448                                                        &record_cnt, &data_cnt,
2449                                                        &partial_copy,
2450                                                        &partial_copy_len,
2451                                                        log_offset,
2452                                                        commit_iclog);
2453                         if (error)
2454                                 return error;
2455
2456                         /*
2457                          * if we had a partial copy, we need to get more iclog
2458                          * space but we don't want to increment the region
2459                          * index because there is still more is this region to
2460                          * write.
2461                          *
2462                          * If we completed writing this region, and we flushed
2463                          * the iclog (indicated by resetting of the record
2464                          * count), then we also need to get more log space. If
2465                          * this was the last record, though, we are done and
2466                          * can just return.
2467                          */
2468                         if (partial_copy)
2469                                 break;
2470
2471                         if (++index == lv->lv_niovecs) {
2472 next_lv:
2473                                 lv = lv->lv_next;
2474                                 index = 0;
2475                                 if (lv)
2476                                         vecp = lv->lv_iovecp;
2477                         }
2478                         if (record_cnt == 0 && !ordered) {
2479                                 if (!lv)
2480                                         return 0;
2481                                 break;
2482                         }
2483                 }
2484         }
2485
2486         ASSERT(len == 0);
2487
2488         xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
2489         if (!commit_iclog)
2490                 return xlog_state_release_iclog(log, iclog);
2491
2492         ASSERT(flags & XLOG_COMMIT_TRANS);
2493         *commit_iclog = iclog;
2494         return 0;
2495 }
2496
2497
2498 /*****************************************************************************
2499  *
2500  *              State Machine functions
2501  *
2502  *****************************************************************************
2503  */
2504
2505 /* Clean iclogs starting from the head.  This ordering must be
2506  * maintained, so an iclog doesn't become ACTIVE beyond one that
2507  * is SYNCING.  This is also required to maintain the notion that we use
2508  * a ordered wait queue to hold off would be writers to the log when every
2509  * iclog is trying to sync to disk.
2510  *
2511  * State Change: DIRTY -> ACTIVE
2512  */
2513 STATIC void
2514 xlog_state_clean_log(
2515         struct xlog *log)
2516 {
2517         xlog_in_core_t  *iclog;
2518         int changed = 0;
2519
2520         iclog = log->l_iclog;
2521         do {
2522                 if (iclog->ic_state == XLOG_STATE_DIRTY) {
2523                         iclog->ic_state = XLOG_STATE_ACTIVE;
2524                         iclog->ic_offset       = 0;
2525                         ASSERT(list_empty_careful(&iclog->ic_callbacks));
2526                         /*
2527                          * If the number of ops in this iclog indicate it just
2528                          * contains the dummy transaction, we can
2529                          * change state into IDLE (the second time around).
2530                          * Otherwise we should change the state into
2531                          * NEED a dummy.
2532                          * We don't need to cover the dummy.
2533                          */
2534                         if (!changed &&
2535                            (be32_to_cpu(iclog->ic_header.h_num_logops) ==
2536                                         XLOG_COVER_OPS)) {
2537                                 changed = 1;
2538                         } else {
2539                                 /*
2540                                  * We have two dirty iclogs so start over
2541                                  * This could also be num of ops indicates
2542                                  * this is not the dummy going out.
2543                                  */
2544                                 changed = 2;
2545                         }
2546                         iclog->ic_header.h_num_logops = 0;
2547                         memset(iclog->ic_header.h_cycle_data, 0,
2548                               sizeof(iclog->ic_header.h_cycle_data));
2549                         iclog->ic_header.h_lsn = 0;
2550                 } else if (iclog->ic_state == XLOG_STATE_ACTIVE)
2551                         /* do nothing */;
2552                 else
2553                         break;  /* stop cleaning */
2554                 iclog = iclog->ic_next;
2555         } while (iclog != log->l_iclog);
2556
2557         /* log is locked when we are called */
2558         /*
2559          * Change state for the dummy log recording.
2560          * We usually go to NEED. But we go to NEED2 if the changed indicates
2561          * we are done writing the dummy record.
2562          * If we are done with the second dummy recored (DONE2), then
2563          * we go to IDLE.
2564          */
2565         if (changed) {
2566                 switch (log->l_covered_state) {
2567                 case XLOG_STATE_COVER_IDLE:
2568                 case XLOG_STATE_COVER_NEED:
2569                 case XLOG_STATE_COVER_NEED2:
2570                         log->l_covered_state = XLOG_STATE_COVER_NEED;
2571                         break;
2572
2573                 case XLOG_STATE_COVER_DONE:
2574                         if (changed == 1)
2575                                 log->l_covered_state = XLOG_STATE_COVER_NEED2;
2576                         else
2577                                 log->l_covered_state = XLOG_STATE_COVER_NEED;
2578                         break;
2579
2580                 case XLOG_STATE_COVER_DONE2:
2581                         if (changed == 1)
2582                                 log->l_covered_state = XLOG_STATE_COVER_IDLE;
2583                         else
2584                                 log->l_covered_state = XLOG_STATE_COVER_NEED;
2585                         break;
2586
2587                 default:
2588                         ASSERT(0);
2589                 }
2590         }
2591 }       /* xlog_state_clean_log */
2592
2593 STATIC xfs_lsn_t
2594 xlog_get_lowest_lsn(
2595         struct xlog             *log)
2596 {
2597         struct xlog_in_core     *iclog = log->l_iclog;
2598         xfs_lsn_t               lowest_lsn = 0, lsn;
2599
2600         do {
2601                 if (iclog->ic_state & (XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY))
2602                         continue;
2603
2604                 lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2605                 if ((lsn && !lowest_lsn) || XFS_LSN_CMP(lsn, lowest_lsn) < 0)
2606                         lowest_lsn = lsn;
2607         } while ((iclog = iclog->ic_next) != log->l_iclog);
2608
2609         return lowest_lsn;
2610 }
2611
2612 STATIC void
2613 xlog_state_do_callback(
2614         struct xlog             *log,
2615         bool                    aborted,
2616         struct xlog_in_core     *ciclog)
2617 {
2618         xlog_in_core_t     *iclog;
2619         xlog_in_core_t     *first_iclog;        /* used to know when we've
2620                                                  * processed all iclogs once */
2621         int                flushcnt = 0;
2622         xfs_lsn_t          lowest_lsn;
2623         int                ioerrors;    /* counter: iclogs with errors */
2624         int                loopdidcallbacks; /* flag: inner loop did callbacks*/
2625         int                funcdidcallbacks; /* flag: function did callbacks */
2626         int                repeats;     /* for issuing console warnings if
2627                                          * looping too many times */
2628         int                wake = 0;
2629
2630         spin_lock(&log->l_icloglock);
2631         first_iclog = iclog = log->l_iclog;
2632         ioerrors = 0;
2633         funcdidcallbacks = 0;
2634         repeats = 0;
2635
2636         do {
2637                 /*
2638                  * Scan all iclogs starting with the one pointed to by the
2639                  * log.  Reset this starting point each time the log is
2640                  * unlocked (during callbacks).
2641                  *
2642                  * Keep looping through iclogs until one full pass is made
2643                  * without running any callbacks.
2644                  */
2645                 first_iclog = log->l_iclog;
2646                 iclog = log->l_iclog;
2647                 loopdidcallbacks = 0;
2648                 repeats++;
2649
2650                 do {
2651
2652                         /* skip all iclogs in the ACTIVE & DIRTY states */
2653                         if (iclog->ic_state &
2654                             (XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY)) {
2655                                 iclog = iclog->ic_next;
2656                                 continue;
2657                         }
2658
2659                         /*
2660                          * Between marking a filesystem SHUTDOWN and stopping
2661                          * the log, we do flush all iclogs to disk (if there
2662                          * wasn't a log I/O error). So, we do want things to
2663                          * go smoothly in case of just a SHUTDOWN  w/o a
2664                          * LOG_IO_ERROR.
2665                          */
2666                         if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
2667                                 /*
2668                                  * Can only perform callbacks in order.  Since
2669                                  * this iclog is not in the DONE_SYNC/
2670                                  * DO_CALLBACK state, we skip the rest and
2671                                  * just try to clean up.  If we set our iclog
2672                                  * to DO_CALLBACK, we will not process it when
2673                                  * we retry since a previous iclog is in the
2674                                  * CALLBACK and the state cannot change since
2675                                  * we are holding the l_icloglock.
2676                                  */
2677                                 if (!(iclog->ic_state &
2678                                         (XLOG_STATE_DONE_SYNC |
2679                                                  XLOG_STATE_DO_CALLBACK))) {
2680                                         if (ciclog && (ciclog->ic_state ==
2681                                                         XLOG_STATE_DONE_SYNC)) {
2682                                                 ciclog->ic_state = XLOG_STATE_DO_CALLBACK;
2683                                         }
2684                                         break;
2685                                 }
2686                                 /*
2687                                  * We now have an iclog that is in either the
2688                                  * DO_CALLBACK or DONE_SYNC states. The other
2689                                  * states (WANT_SYNC, SYNCING, or CALLBACK were
2690                                  * caught by the above if and are going to
2691                                  * clean (i.e. we aren't doing their callbacks)
2692                                  * see the above if.
2693                                  */
2694
2695                                 /*
2696                                  * We will do one more check here to see if we
2697                                  * have chased our tail around.
2698                                  */
2699
2700                                 lowest_lsn = xlog_get_lowest_lsn(log);
2701                                 if (lowest_lsn &&
2702                                     XFS_LSN_CMP(lowest_lsn,
2703                                                 be64_to_cpu(iclog->ic_header.h_lsn)) < 0) {
2704                                         iclog = iclog->ic_next;
2705                                         continue; /* Leave this iclog for
2706                                                    * another thread */
2707                                 }
2708
2709                                 iclog->ic_state = XLOG_STATE_CALLBACK;
2710
2711
2712                                 /*
2713                                  * Completion of a iclog IO does not imply that
2714                                  * a transaction has completed, as transactions
2715                                  * can be large enough to span many iclogs. We
2716                                  * cannot change the tail of the log half way
2717                                  * through a transaction as this may be the only
2718                                  * transaction in the log and moving th etail to
2719                                  * point to the middle of it will prevent
2720                                  * recovery from finding the start of the
2721                                  * transaction. Hence we should only update the
2722                                  * last_sync_lsn if this iclog contains
2723                                  * transaction completion callbacks on it.
2724                                  *
2725                                  * We have to do this before we drop the
2726                                  * icloglock to ensure we are the only one that
2727                                  * can update it.
2728                                  */
2729                                 ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
2730                                         be64_to_cpu(iclog->ic_header.h_lsn)) <= 0);
2731                                 if (!list_empty_careful(&iclog->ic_callbacks))
2732                                         atomic64_set(&log->l_last_sync_lsn,
2733                                                 be64_to_cpu(iclog->ic_header.h_lsn));
2734
2735                         } else
2736                                 ioerrors++;
2737
2738                         spin_unlock(&log->l_icloglock);
2739
2740                         /*
2741                          * Keep processing entries in the callback list until
2742                          * we come around and it is empty.  We need to
2743                          * atomically see that the list is empty and change the
2744                          * state to DIRTY so that we don't miss any more
2745                          * callbacks being added.
2746                          */
2747                         spin_lock(&iclog->ic_callback_lock);
2748                         while (!list_empty(&iclog->ic_callbacks)) {
2749                                 LIST_HEAD(tmp);
2750
2751                                 list_splice_init(&iclog->ic_callbacks, &tmp);
2752
2753                                 spin_unlock(&iclog->ic_callback_lock);
2754                                 xlog_cil_process_committed(&tmp, aborted);
2755                                 spin_lock(&iclog->ic_callback_lock);
2756                         }
2757
2758                         loopdidcallbacks++;
2759                         funcdidcallbacks++;
2760
2761                         spin_lock(&log->l_icloglock);
2762                         spin_unlock(&iclog->ic_callback_lock);
2763                         if (!(iclog->ic_state & XLOG_STATE_IOERROR))
2764                                 iclog->ic_state = XLOG_STATE_DIRTY;
2765
2766                         /*
2767                          * Transition from DIRTY to ACTIVE if applicable.
2768                          * NOP if STATE_IOERROR.
2769                          */
2770                         xlog_state_clean_log(log);
2771
2772                         /* wake up threads waiting in xfs_log_force() */
2773                         wake_up_all(&iclog->ic_force_wait);
2774
2775                         iclog = iclog->ic_next;
2776                 } while (first_iclog != iclog);
2777
2778                 if (repeats > 5000) {
2779                         flushcnt += repeats;
2780                         repeats = 0;
2781                         xfs_warn(log->l_mp,
2782                                 "%s: possible infinite loop (%d iterations)",
2783                                 __func__, flushcnt);
2784                 }
2785         } while (!ioerrors && loopdidcallbacks);
2786
2787 #ifdef DEBUG
2788         /*
2789          * Make one last gasp attempt to see if iclogs are being left in limbo.
2790          * If the above loop finds an iclog earlier than the current iclog and
2791          * in one of the syncing states, the current iclog is put into
2792          * DO_CALLBACK and the callbacks are deferred to the completion of the
2793          * earlier iclog. Walk the iclogs in order and make sure that no iclog
2794          * is in DO_CALLBACK unless an earlier iclog is in one of the syncing
2795          * states.
2796          *
2797          * Note that SYNCING|IOABORT is a valid state so we cannot just check
2798          * for ic_state == SYNCING.
2799          */
2800         if (funcdidcallbacks) {
2801                 first_iclog = iclog = log->l_iclog;
2802                 do {
2803                         ASSERT(iclog->ic_state != XLOG_STATE_DO_CALLBACK);
2804                         /*
2805                          * Terminate the loop if iclogs are found in states
2806                          * which will cause other threads to clean up iclogs.
2807                          *
2808                          * SYNCING - i/o completion will go through logs
2809                          * DONE_SYNC - interrupt thread should be waiting for
2810                          *              l_icloglock
2811                          * IOERROR - give up hope all ye who enter here
2812                          */
2813                         if (iclog->ic_state == XLOG_STATE_WANT_SYNC ||
2814                             iclog->ic_state & XLOG_STATE_SYNCING ||
2815                             iclog->ic_state == XLOG_STATE_DONE_SYNC ||
2816                             iclog->ic_state == XLOG_STATE_IOERROR )
2817                                 break;
2818                         iclog = iclog->ic_next;
2819                 } while (first_iclog != iclog);
2820         }
2821 #endif
2822
2823         if (log->l_iclog->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_IOERROR))
2824                 wake = 1;
2825         spin_unlock(&log->l_icloglock);
2826
2827         if (wake)
2828                 wake_up_all(&log->l_flush_wait);
2829 }
2830
2831
2832 /*
2833  * Finish transitioning this iclog to the dirty state.
2834  *
2835  * Make sure that we completely execute this routine only when this is
2836  * the last call to the iclog.  There is a good chance that iclog flushes,
2837  * when we reach the end of the physical log, get turned into 2 separate
2838  * calls to bwrite.  Hence, one iclog flush could generate two calls to this
2839  * routine.  By using the reference count bwritecnt, we guarantee that only
2840  * the second completion goes through.
2841  *
2842  * Callbacks could take time, so they are done outside the scope of the
2843  * global state machine log lock.
2844  */
2845 STATIC void
2846 xlog_state_done_syncing(
2847         struct xlog_in_core     *iclog,
2848         bool                    aborted)
2849 {
2850         struct xlog             *log = iclog->ic_log;
2851
2852         spin_lock(&log->l_icloglock);
2853
2854         ASSERT(iclog->ic_state == XLOG_STATE_SYNCING ||
2855                iclog->ic_state == XLOG_STATE_IOERROR);
2856         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
2857
2858         /*
2859          * If we got an error, either on the first buffer, or in the case of
2860          * split log writes, on the second, we mark ALL iclogs STATE_IOERROR,
2861          * and none should ever be attempted to be written to disk
2862          * again.
2863          */
2864         if (iclog->ic_state != XLOG_STATE_IOERROR)
2865                 iclog->ic_state = XLOG_STATE_DONE_SYNC;
2866
2867         /*
2868          * Someone could be sleeping prior to writing out the next
2869          * iclog buffer, we wake them all, one will get to do the
2870          * I/O, the others get to wait for the result.
2871          */
2872         wake_up_all(&iclog->ic_write_wait);
2873         spin_unlock(&log->l_icloglock);
2874         xlog_state_do_callback(log, aborted, iclog);    /* also cleans log */
2875 }       /* xlog_state_done_syncing */
2876
2877
2878 /*
2879  * If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
2880  * sleep.  We wait on the flush queue on the head iclog as that should be
2881  * the first iclog to complete flushing. Hence if all iclogs are syncing,
2882  * we will wait here and all new writes will sleep until a sync completes.
2883  *
2884  * The in-core logs are used in a circular fashion. They are not used
2885  * out-of-order even when an iclog past the head is free.
2886  *
2887  * return:
2888  *      * log_offset where xlog_write() can start writing into the in-core
2889  *              log's data space.
2890  *      * in-core log pointer to which xlog_write() should write.
2891  *      * boolean indicating this is a continued write to an in-core log.
2892  *              If this is the last write, then the in-core log's offset field
2893  *              needs to be incremented, depending on the amount of data which
2894  *              is copied.
2895  */
2896 STATIC int
2897 xlog_state_get_iclog_space(
2898         struct xlog             *log,
2899         int                     len,
2900         struct xlog_in_core     **iclogp,
2901         struct xlog_ticket      *ticket,
2902         int                     *continued_write,
2903         int                     *logoffsetp)
2904 {
2905         int               log_offset;
2906         xlog_rec_header_t *head;
2907         xlog_in_core_t    *iclog;
2908         int               error;
2909
2910 restart:
2911         spin_lock(&log->l_icloglock);
2912         if (XLOG_FORCED_SHUTDOWN(log)) {
2913                 spin_unlock(&log->l_icloglock);
2914                 return -EIO;
2915         }
2916
2917         iclog = log->l_iclog;
2918         if (iclog->ic_state != XLOG_STATE_ACTIVE) {
2919                 XFS_STATS_INC(log->l_mp, xs_log_noiclogs);
2920
2921                 /* Wait for log writes to have flushed */
2922                 xlog_wait(&log->l_flush_wait, &log->l_icloglock);
2923                 goto restart;
2924         }
2925
2926         head = &iclog->ic_header;
2927
2928         atomic_inc(&iclog->ic_refcnt);  /* prevents sync */
2929         log_offset = iclog->ic_offset;
2930
2931         /* On the 1st write to an iclog, figure out lsn.  This works
2932          * if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
2933          * committing to.  If the offset is set, that's how many blocks
2934          * must be written.
2935          */
2936         if (log_offset == 0) {
2937                 ticket->t_curr_res -= log->l_iclog_hsize;
2938                 xlog_tic_add_region(ticket,
2939                                     log->l_iclog_hsize,
2940                                     XLOG_REG_TYPE_LRHEADER);
2941                 head->h_cycle = cpu_to_be32(log->l_curr_cycle);
2942                 head->h_lsn = cpu_to_be64(
2943                         xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
2944                 ASSERT(log->l_curr_block >= 0);
2945         }
2946
2947         /* If there is enough room to write everything, then do it.  Otherwise,
2948          * claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
2949          * bit is on, so this will get flushed out.  Don't update ic_offset
2950          * until you know exactly how many bytes get copied.  Therefore, wait
2951          * until later to update ic_offset.
2952          *
2953          * xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
2954          * can fit into remaining data section.
2955          */
2956         if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
2957                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2958
2959                 /*
2960                  * If I'm the only one writing to this iclog, sync it to disk.
2961                  * We need to do an atomic compare and decrement here to avoid
2962                  * racing with concurrent atomic_dec_and_lock() calls in
2963                  * xlog_state_release_iclog() when there is more than one
2964                  * reference to the iclog.
2965                  */
2966                 if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1)) {
2967                         /* we are the only one */
2968                         spin_unlock(&log->l_icloglock);
2969                         error = xlog_state_release_iclog(log, iclog);
2970                         if (error)
2971                                 return error;
2972                 } else {
2973                         spin_unlock(&log->l_icloglock);
2974                 }
2975                 goto restart;
2976         }
2977
2978         /* Do we have enough room to write the full amount in the remainder
2979          * of this iclog?  Or must we continue a write on the next iclog and
2980          * mark this iclog as completely taken?  In the case where we switch
2981          * iclogs (to mark it taken), this particular iclog will release/sync
2982          * to disk in xlog_write().
2983          */
2984         if (len <= iclog->ic_size - iclog->ic_offset) {
2985                 *continued_write = 0;
2986                 iclog->ic_offset += len;
2987         } else {
2988                 *continued_write = 1;
2989                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2990         }
2991         *iclogp = iclog;
2992
2993         ASSERT(iclog->ic_offset <= iclog->ic_size);
2994         spin_unlock(&log->l_icloglock);
2995
2996         *logoffsetp = log_offset;
2997         return 0;
2998 }       /* xlog_state_get_iclog_space */
2999
3000 /* The first cnt-1 times through here we don't need to
3001  * move the grant write head because the permanent
3002  * reservation has reserved cnt times the unit amount.
3003  * Release part of current permanent unit reservation and
3004  * reset current reservation to be one units worth.  Also
3005  * move grant reservation head forward.
3006  */
3007 STATIC void
3008 xlog_regrant_reserve_log_space(
3009         struct xlog             *log,
3010         struct xlog_ticket      *ticket)
3011 {
3012         trace_xfs_log_regrant_reserve_enter(log, ticket);
3013
3014         if (ticket->t_cnt > 0)
3015                 ticket->t_cnt--;
3016
3017         xlog_grant_sub_space(log, &log->l_reserve_head.grant,
3018                                         ticket->t_curr_res);
3019         xlog_grant_sub_space(log, &log->l_write_head.grant,
3020                                         ticket->t_curr_res);
3021         ticket->t_curr_res = ticket->t_unit_res;
3022         xlog_tic_reset_res(ticket);
3023
3024         trace_xfs_log_regrant_reserve_sub(log, ticket);
3025
3026         /* just return if we still have some of the pre-reserved space */
3027         if (ticket->t_cnt > 0)
3028                 return;
3029
3030         xlog_grant_add_space(log, &log->l_reserve_head.grant,
3031                                         ticket->t_unit_res);
3032
3033         trace_xfs_log_regrant_reserve_exit(log, ticket);
3034
3035         ticket->t_curr_res = ticket->t_unit_res;
3036         xlog_tic_reset_res(ticket);
3037 }       /* xlog_regrant_reserve_log_space */
3038
3039
3040 /*
3041  * Give back the space left from a reservation.
3042  *
3043  * All the information we need to make a correct determination of space left
3044  * is present.  For non-permanent reservations, things are quite easy.  The
3045  * count should have been decremented to zero.  We only need to deal with the
3046  * space remaining in the current reservation part of the ticket.  If the
3047  * ticket contains a permanent reservation, there may be left over space which
3048  * needs to be released.  A count of N means that N-1 refills of the current
3049  * reservation can be done before we need to ask for more space.  The first
3050  * one goes to fill up the first current reservation.  Once we run out of
3051  * space, the count will stay at zero and the only space remaining will be
3052  * in the current reservation field.
3053  */
3054 STATIC void
3055 xlog_ungrant_log_space(
3056         struct xlog             *log,
3057         struct xlog_ticket      *ticket)
3058 {
3059         int     bytes;
3060
3061         if (ticket->t_cnt > 0)
3062                 ticket->t_cnt--;
3063
3064         trace_xfs_log_ungrant_enter(log, ticket);
3065         trace_xfs_log_ungrant_sub(log, ticket);
3066
3067         /*
3068          * If this is a permanent reservation ticket, we may be able to free
3069          * up more space based on the remaining count.
3070          */
3071         bytes = ticket->t_curr_res;
3072         if (ticket->t_cnt > 0) {
3073                 ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
3074                 bytes += ticket->t_unit_res*ticket->t_cnt;
3075         }
3076
3077         xlog_grant_sub_space(log, &log->l_reserve_head.grant, bytes);
3078         xlog_grant_sub_space(log, &log->l_write_head.grant, bytes);
3079
3080         trace_xfs_log_ungrant_exit(log, ticket);
3081
3082         xfs_log_space_wake(log->l_mp);
3083 }
3084
3085 /*
3086  * Flush iclog to disk if this is the last reference to the given iclog and
3087  * the WANT_SYNC bit is set.
3088  *
3089  * When this function is entered, the iclog is not necessarily in the
3090  * WANT_SYNC state.  It may be sitting around waiting to get filled.
3091  *
3092  *
3093  */
3094 STATIC int
3095 xlog_state_release_iclog(
3096         struct xlog             *log,
3097         struct xlog_in_core     *iclog)
3098 {
3099         int             sync = 0;       /* do we sync? */
3100
3101         if (iclog->ic_state & XLOG_STATE_IOERROR)
3102                 return -EIO;
3103
3104         ASSERT(atomic_read(&iclog->ic_refcnt) > 0);
3105         if (!atomic_dec_and_lock(&iclog->ic_refcnt, &log->l_icloglock))
3106                 return 0;
3107
3108         if (iclog->ic_state & XLOG_STATE_IOERROR) {
3109                 spin_unlock(&log->l_icloglock);
3110                 return -EIO;
3111         }
3112         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE ||
3113                iclog->ic_state == XLOG_STATE_WANT_SYNC);
3114
3115         if (iclog->ic_state == XLOG_STATE_WANT_SYNC) {
3116                 /* update tail before writing to iclog */
3117                 xfs_lsn_t tail_lsn = xlog_assign_tail_lsn(log->l_mp);
3118                 sync++;
3119                 iclog->ic_state = XLOG_STATE_SYNCING;
3120                 iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn);
3121                 xlog_verify_tail_lsn(log, iclog, tail_lsn);
3122                 /* cycle incremented when incrementing curr_block */
3123         }
3124         spin_unlock(&log->l_icloglock);
3125
3126         /*
3127          * We let the log lock go, so it's possible that we hit a log I/O
3128          * error or some other SHUTDOWN condition that marks the iclog
3129          * as XLOG_STATE_IOERROR before the bwrite. However, we know that
3130          * this iclog has consistent data, so we ignore IOERROR
3131          * flags after this point.
3132          */
3133         if (sync)
3134                 xlog_sync(log, iclog);
3135         return 0;
3136 }       /* xlog_state_release_iclog */
3137
3138
3139 /*
3140  * This routine will mark the current iclog in the ring as WANT_SYNC
3141  * and move the current iclog pointer to the next iclog in the ring.
3142  * When this routine is called from xlog_state_get_iclog_space(), the
3143  * exact size of the iclog has not yet been determined.  All we know is
3144  * that every data block.  We have run out of space in this log record.
3145  */
3146 STATIC void
3147 xlog_state_switch_iclogs(
3148         struct xlog             *log,
3149         struct xlog_in_core     *iclog,
3150         int                     eventual_size)
3151 {
3152         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
3153         if (!eventual_size)
3154                 eventual_size = iclog->ic_offset;
3155         iclog->ic_state = XLOG_STATE_WANT_SYNC;
3156         iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
3157         log->l_prev_block = log->l_curr_block;
3158         log->l_prev_cycle = log->l_curr_cycle;
3159
3160         /* roll log?: ic_offset changed later */
3161         log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
3162
3163         /* Round up to next log-sunit */
3164         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
3165             log->l_mp->m_sb.sb_logsunit > 1) {
3166                 uint32_t sunit_bb = BTOBB(log->l_mp->m_sb.sb_logsunit);
3167                 log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
3168         }
3169
3170         if (log->l_curr_block >= log->l_logBBsize) {
3171                 /*
3172                  * Rewind the current block before the cycle is bumped to make
3173                  * sure that the combined LSN never transiently moves forward
3174                  * when the log wraps to the next cycle. This is to support the
3175                  * unlocked sample of these fields from xlog_valid_lsn(). Most
3176                  * other cases should acquire l_icloglock.
3177                  */
3178                 log->l_curr_block -= log->l_logBBsize;
3179                 ASSERT(log->l_curr_block >= 0);
3180                 smp_wmb();
3181                 log->l_curr_cycle++;
3182                 if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
3183                         log->l_curr_cycle++;
3184         }
3185         ASSERT(iclog == log->l_iclog);
3186         log->l_iclog = iclog->ic_next;
3187 }       /* xlog_state_switch_iclogs */
3188
3189 /*
3190  * Write out all data in the in-core log as of this exact moment in time.
3191  *
3192  * Data may be written to the in-core log during this call.  However,
3193  * we don't guarantee this data will be written out.  A change from past
3194  * implementation means this routine will *not* write out zero length LRs.
3195  *
3196  * Basically, we try and perform an intelligent scan of the in-core logs.
3197  * If we determine there is no flushable data, we just return.  There is no
3198  * flushable data if:
3199  *
3200  *      1. the current iclog is active and has no data; the previous iclog
3201  *              is in the active or dirty state.
3202  *      2. the current iclog is drity, and the previous iclog is in the
3203  *              active or dirty state.
3204  *
3205  * We may sleep if:
3206  *
3207  *      1. the current iclog is not in the active nor dirty state.
3208  *      2. the current iclog dirty, and the previous iclog is not in the
3209  *              active nor dirty state.
3210  *      3. the current iclog is active, and there is another thread writing
3211  *              to this particular iclog.
3212  *      4. a) the current iclog is active and has no other writers
3213  *         b) when we return from flushing out this iclog, it is still
3214  *              not in the active nor dirty state.
3215  */
3216 int
3217 xfs_log_force(
3218         struct xfs_mount        *mp,
3219         uint                    flags)
3220 {
3221         struct xlog             *log = mp->m_log;
3222         struct xlog_in_core     *iclog;
3223         xfs_lsn_t               lsn;
3224
3225         XFS_STATS_INC(mp, xs_log_force);
3226         trace_xfs_log_force(mp, 0, _RET_IP_);
3227
3228         xlog_cil_force(log);
3229
3230         spin_lock(&log->l_icloglock);
3231         iclog = log->l_iclog;
3232         if (iclog->ic_state & XLOG_STATE_IOERROR)
3233                 goto out_error;
3234
3235         if (iclog->ic_state == XLOG_STATE_DIRTY ||
3236             (iclog->ic_state == XLOG_STATE_ACTIVE &&
3237              atomic_read(&iclog->ic_refcnt) == 0 && iclog->ic_offset == 0)) {
3238                 /*
3239                  * If the head is dirty or (active and empty), then we need to
3240                  * look at the previous iclog.
3241                  *
3242                  * If the previous iclog is active or dirty we are done.  There
3243                  * is nothing to sync out. Otherwise, we attach ourselves to the
3244                  * previous iclog and go to sleep.
3245                  */
3246                 iclog = iclog->ic_prev;
3247                 if (iclog->ic_state == XLOG_STATE_ACTIVE ||
3248                     iclog->ic_state == XLOG_STATE_DIRTY)
3249                         goto out_unlock;
3250         } else if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3251                 if (atomic_read(&iclog->ic_refcnt) == 0) {
3252                         /*
3253                          * We are the only one with access to this iclog.
3254                          *
3255                          * Flush it out now.  There should be a roundoff of zero
3256                          * to show that someone has already taken care of the
3257                          * roundoff from the previous sync.
3258                          */
3259                         atomic_inc(&iclog->ic_refcnt);
3260                         lsn = be64_to_cpu(iclog->ic_header.h_lsn);
3261                         xlog_state_switch_iclogs(log, iclog, 0);
3262                         spin_unlock(&log->l_icloglock);
3263
3264                         if (xlog_state_release_iclog(log, iclog))
3265                                 return -EIO;
3266
3267                         spin_lock(&log->l_icloglock);
3268                         if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn ||
3269                             iclog->ic_state == XLOG_STATE_DIRTY)
3270                                 goto out_unlock;
3271                 } else {
3272                         /*
3273                          * Someone else is writing to this iclog.
3274                          *
3275                          * Use its call to flush out the data.  However, the
3276                          * other thread may not force out this LR, so we mark
3277                          * it WANT_SYNC.
3278                          */
3279                         xlog_state_switch_iclogs(log, iclog, 0);
3280                 }
3281         } else {
3282                 /*
3283                  * If the head iclog is not active nor dirty, we just attach
3284                  * ourselves to the head and go to sleep if necessary.
3285                  */
3286                 ;
3287         }
3288
3289         if (!(flags & XFS_LOG_SYNC))
3290                 goto out_unlock;
3291
3292         if (iclog->ic_state & XLOG_STATE_IOERROR)
3293                 goto out_error;
3294         XFS_STATS_INC(mp, xs_log_force_sleep);
3295         xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
3296         if (iclog->ic_state & XLOG_STATE_IOERROR)
3297                 return -EIO;
3298         return 0;
3299
3300 out_unlock:
3301         spin_unlock(&log->l_icloglock);
3302         return 0;
3303 out_error:
3304         spin_unlock(&log->l_icloglock);
3305         return -EIO;
3306 }
3307
3308 static int
3309 __xfs_log_force_lsn(
3310         struct xfs_mount        *mp,
3311         xfs_lsn_t               lsn,
3312         uint                    flags,
3313         int                     *log_flushed,
3314         bool                    already_slept)
3315 {
3316         struct xlog             *log = mp->m_log;
3317         struct xlog_in_core     *iclog;
3318
3319         spin_lock(&log->l_icloglock);
3320         iclog = log->l_iclog;
3321         if (iclog->ic_state & XLOG_STATE_IOERROR)
3322                 goto out_error;
3323
3324         while (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
3325                 iclog = iclog->ic_next;
3326                 if (iclog == log->l_iclog)
3327                         goto out_unlock;
3328         }
3329
3330         if (iclog->ic_state == XLOG_STATE_DIRTY)
3331                 goto out_unlock;
3332
3333         if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3334                 /*
3335                  * We sleep here if we haven't already slept (e.g. this is the
3336                  * first time we've looked at the correct iclog buf) and the
3337                  * buffer before us is going to be sync'ed.  The reason for this
3338                  * is that if we are doing sync transactions here, by waiting
3339                  * for the previous I/O to complete, we can allow a few more
3340                  * transactions into this iclog before we close it down.
3341                  *
3342                  * Otherwise, we mark the buffer WANT_SYNC, and bump up the
3343                  * refcnt so we can release the log (which drops the ref count).
3344                  * The state switch keeps new transaction commits from using
3345                  * this buffer.  When the current commits finish writing into
3346                  * the buffer, the refcount will drop to zero and the buffer
3347                  * will go out then.
3348                  */
3349                 if (!already_slept &&
3350                     (iclog->ic_prev->ic_state &
3351                      (XLOG_STATE_WANT_SYNC | XLOG_STATE_SYNCING))) {
3352                         ASSERT(!(iclog->ic_state & XLOG_STATE_IOERROR));
3353
3354                         XFS_STATS_INC(mp, xs_log_force_sleep);
3355
3356                         xlog_wait(&iclog->ic_prev->ic_write_wait,
3357                                         &log->l_icloglock);
3358                         return -EAGAIN;
3359                 }
3360                 atomic_inc(&iclog->ic_refcnt);
3361                 xlog_state_switch_iclogs(log, iclog, 0);
3362                 spin_unlock(&log->l_icloglock);
3363                 if (xlog_state_release_iclog(log, iclog))
3364                         return -EIO;
3365                 if (log_flushed)
3366                         *log_flushed = 1;
3367                 spin_lock(&log->l_icloglock);
3368         }
3369
3370         if (!(flags & XFS_LOG_SYNC) ||
3371             (iclog->ic_state & (XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY)))
3372                 goto out_unlock;
3373
3374         if (iclog->ic_state & XLOG_STATE_IOERROR)
3375                 goto out_error;
3376
3377         XFS_STATS_INC(mp, xs_log_force_sleep);
3378         xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
3379         if (iclog->ic_state & XLOG_STATE_IOERROR)
3380                 return -EIO;
3381         return 0;
3382
3383 out_unlock:
3384         spin_unlock(&log->l_icloglock);
3385         return 0;
3386 out_error:
3387         spin_unlock(&log->l_icloglock);
3388         return -EIO;
3389 }
3390
3391 /*
3392  * Force the in-core log to disk for a specific LSN.
3393  *
3394  * Find in-core log with lsn.
3395  *      If it is in the DIRTY state, just return.
3396  *      If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
3397  *              state and go to sleep or return.
3398  *      If it is in any other state, go to sleep or return.
3399  *
3400  * Synchronous forces are implemented with a wait queue.  All callers trying
3401  * to force a given lsn to disk must wait on the queue attached to the
3402  * specific in-core log.  When given in-core log finally completes its write
3403  * to disk, that thread will wake up all threads waiting on the queue.
3404  */
3405 int
3406 xfs_log_force_lsn(
3407         struct xfs_mount        *mp,
3408         xfs_lsn_t               lsn,
3409         uint                    flags,
3410         int                     *log_flushed)
3411 {
3412         int                     ret;
3413         ASSERT(lsn != 0);
3414
3415         XFS_STATS_INC(mp, xs_log_force);
3416         trace_xfs_log_force(mp, lsn, _RET_IP_);
3417
3418         lsn = xlog_cil_force_lsn(mp->m_log, lsn);
3419         if (lsn == NULLCOMMITLSN)
3420                 return 0;
3421
3422         ret = __xfs_log_force_lsn(mp, lsn, flags, log_flushed, false);
3423         if (ret == -EAGAIN)
3424                 ret = __xfs_log_force_lsn(mp, lsn, flags, log_flushed, true);
3425         return ret;
3426 }
3427
3428 /*
3429  * Called when we want to mark the current iclog as being ready to sync to
3430  * disk.
3431  */
3432 STATIC void
3433 xlog_state_want_sync(
3434         struct xlog             *log,
3435         struct xlog_in_core     *iclog)
3436 {
3437         assert_spin_locked(&log->l_icloglock);
3438
3439         if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3440                 xlog_state_switch_iclogs(log, iclog, 0);
3441         } else {
3442                 ASSERT(iclog->ic_state &
3443                         (XLOG_STATE_WANT_SYNC|XLOG_STATE_IOERROR));
3444         }
3445 }
3446
3447
3448 /*****************************************************************************
3449  *
3450  *              TICKET functions
3451  *
3452  *****************************************************************************
3453  */
3454
3455 /*
3456  * Free a used ticket when its refcount falls to zero.
3457  */
3458 void
3459 xfs_log_ticket_put(
3460         xlog_ticket_t   *ticket)
3461 {
3462         ASSERT(atomic_read(&ticket->t_ref) > 0);
3463         if (atomic_dec_and_test(&ticket->t_ref))
3464                 kmem_zone_free(xfs_log_ticket_zone, ticket);
3465 }
3466
3467 xlog_ticket_t *
3468 xfs_log_ticket_get(
3469         xlog_ticket_t   *ticket)
3470 {
3471         ASSERT(atomic_read(&ticket->t_ref) > 0);
3472         atomic_inc(&ticket->t_ref);
3473         return ticket;
3474 }
3475
3476 /*
3477  * Figure out the total log space unit (in bytes) that would be
3478  * required for a log ticket.
3479  */
3480 int
3481 xfs_log_calc_unit_res(
3482         struct xfs_mount        *mp,
3483         int                     unit_bytes)
3484 {
3485         struct xlog             *log = mp->m_log;
3486         int                     iclog_space;
3487         uint                    num_headers;
3488
3489         /*
3490          * Permanent reservations have up to 'cnt'-1 active log operations
3491          * in the log.  A unit in this case is the amount of space for one
3492          * of these log operations.  Normal reservations have a cnt of 1
3493          * and their unit amount is the total amount of space required.
3494          *
3495          * The following lines of code account for non-transaction data
3496          * which occupy space in the on-disk log.
3497          *
3498          * Normal form of a transaction is:
3499          * <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
3500          * and then there are LR hdrs, split-recs and roundoff at end of syncs.
3501          *
3502          * We need to account for all the leadup data and trailer data
3503          * around the transaction data.
3504          * And then we need to account for the worst case in terms of using
3505          * more space.
3506          * The worst case will happen if:
3507          * - the placement of the transaction happens to be such that the
3508          *   roundoff is at its maximum
3509          * - the transaction data is synced before the commit record is synced
3510          *   i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
3511          *   Therefore the commit record is in its own Log Record.
3512          *   This can happen as the commit record is called with its
3513          *   own region to xlog_write().
3514          *   This then means that in the worst case, roundoff can happen for
3515          *   the commit-rec as well.
3516          *   The commit-rec is smaller than padding in this scenario and so it is
3517          *   not added separately.
3518          */
3519
3520         /* for trans header */
3521         unit_bytes += sizeof(xlog_op_header_t);
3522         unit_bytes += sizeof(xfs_trans_header_t);
3523
3524         /* for start-rec */
3525         unit_bytes += sizeof(xlog_op_header_t);
3526
3527         /*
3528          * for LR headers - the space for data in an iclog is the size minus
3529          * the space used for the headers. If we use the iclog size, then we
3530          * undercalculate the number of headers required.
3531          *
3532          * Furthermore - the addition of op headers for split-recs might
3533          * increase the space required enough to require more log and op
3534          * headers, so take that into account too.
3535          *
3536          * IMPORTANT: This reservation makes the assumption that if this
3537          * transaction is the first in an iclog and hence has the LR headers
3538          * accounted to it, then the remaining space in the iclog is
3539          * exclusively for this transaction.  i.e. if the transaction is larger
3540          * than the iclog, it will be the only thing in that iclog.
3541          * Fundamentally, this means we must pass the entire log vector to
3542          * xlog_write to guarantee this.
3543          */
3544         iclog_space = log->l_iclog_size - log->l_iclog_hsize;
3545         num_headers = howmany(unit_bytes, iclog_space);
3546
3547         /* for split-recs - ophdrs added when data split over LRs */
3548         unit_bytes += sizeof(xlog_op_header_t) * num_headers;
3549
3550         /* add extra header reservations if we overrun */
3551         while (!num_headers ||
3552                howmany(unit_bytes, iclog_space) > num_headers) {
3553                 unit_bytes += sizeof(xlog_op_header_t);
3554                 num_headers++;
3555         }
3556         unit_bytes += log->l_iclog_hsize * num_headers;
3557
3558         /* for commit-rec LR header - note: padding will subsume the ophdr */
3559         unit_bytes += log->l_iclog_hsize;
3560
3561         /* for roundoff padding for transaction data and one for commit record */
3562         if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1) {
3563                 /* log su roundoff */
3564                 unit_bytes += 2 * mp->m_sb.sb_logsunit;
3565         } else {
3566                 /* BB roundoff */
3567                 unit_bytes += 2 * BBSIZE;
3568         }
3569
3570         return unit_bytes;
3571 }
3572
3573 /*
3574  * Allocate and initialise a new log ticket.
3575  */
3576 struct xlog_ticket *
3577 xlog_ticket_alloc(
3578         struct xlog             *log,
3579         int                     unit_bytes,
3580         int                     cnt,
3581         char                    client,
3582         bool                    permanent,
3583         xfs_km_flags_t          alloc_flags)
3584 {
3585         struct xlog_ticket      *tic;
3586         int                     unit_res;
3587
3588         tic = kmem_zone_zalloc(xfs_log_ticket_zone, alloc_flags);
3589         if (!tic)
3590                 return NULL;
3591
3592         unit_res = xfs_log_calc_unit_res(log->l_mp, unit_bytes);
3593
3594         atomic_set(&tic->t_ref, 1);
3595         tic->t_task             = current;
3596         INIT_LIST_HEAD(&tic->t_queue);
3597         tic->t_unit_res         = unit_res;
3598         tic->t_curr_res         = unit_res;
3599         tic->t_cnt              = cnt;
3600         tic->t_ocnt             = cnt;
3601         tic->t_tid              = prandom_u32();
3602         tic->t_clientid         = client;
3603         tic->t_flags            = XLOG_TIC_INITED;
3604         if (permanent)
3605                 tic->t_flags |= XLOG_TIC_PERM_RESERV;
3606
3607         xlog_tic_reset_res(tic);
3608
3609         return tic;
3610 }
3611
3612
3613 /******************************************************************************
3614  *
3615  *              Log debug routines
3616  *
3617  ******************************************************************************
3618  */
3619 #if defined(DEBUG)
3620 /*
3621  * Make sure that the destination ptr is within the valid data region of
3622  * one of the iclogs.  This uses backup pointers stored in a different
3623  * part of the log in case we trash the log structure.
3624  */
3625 STATIC void
3626 xlog_verify_dest_ptr(
3627         struct xlog     *log,
3628         void            *ptr)
3629 {
3630         int i;
3631         int good_ptr = 0;
3632
3633         for (i = 0; i < log->l_iclog_bufs; i++) {
3634                 if (ptr >= log->l_iclog_bak[i] &&
3635                     ptr <= log->l_iclog_bak[i] + log->l_iclog_size)
3636                         good_ptr++;
3637         }
3638
3639         if (!good_ptr)
3640                 xfs_emerg(log->l_mp, "%s: invalid ptr", __func__);
3641 }
3642
3643 /*
3644  * Check to make sure the grant write head didn't just over lap the tail.  If
3645  * the cycles are the same, we can't be overlapping.  Otherwise, make sure that
3646  * the cycles differ by exactly one and check the byte count.
3647  *
3648  * This check is run unlocked, so can give false positives. Rather than assert
3649  * on failures, use a warn-once flag and a panic tag to allow the admin to
3650  * determine if they want to panic the machine when such an error occurs. For
3651  * debug kernels this will have the same effect as using an assert but, unlinke
3652  * an assert, it can be turned off at runtime.
3653  */
3654 STATIC void
3655 xlog_verify_grant_tail(
3656         struct xlog     *log)
3657 {
3658         int             tail_cycle, tail_blocks;
3659         int             cycle, space;
3660
3661         xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &space);
3662         xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
3663         if (tail_cycle != cycle) {
3664                 if (cycle - 1 != tail_cycle &&
3665                     !(log->l_flags & XLOG_TAIL_WARN)) {
3666                         xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3667                                 "%s: cycle - 1 != tail_cycle", __func__);
3668                         log->l_flags |= XLOG_TAIL_WARN;
3669                 }
3670
3671                 if (space > BBTOB(tail_blocks) &&
3672                     !(log->l_flags & XLOG_TAIL_WARN)) {
3673                         xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3674                                 "%s: space > BBTOB(tail_blocks)", __func__);
3675                         log->l_flags |= XLOG_TAIL_WARN;
3676                 }
3677         }
3678 }
3679
3680 /* check if it will fit */
3681 STATIC void
3682 xlog_verify_tail_lsn(
3683         struct xlog             *log,
3684         struct xlog_in_core     *iclog,
3685         xfs_lsn_t               tail_lsn)
3686 {
3687     int blocks;
3688
3689     if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
3690         blocks =
3691             log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
3692         if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
3693                 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3694     } else {
3695         ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
3696
3697         if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
3698                 xfs_emerg(log->l_mp, "%s: tail wrapped", __func__);
3699
3700         blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
3701         if (blocks < BTOBB(iclog->ic_offset) + 1)
3702                 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3703     }
3704 }       /* xlog_verify_tail_lsn */
3705
3706 /*
3707  * Perform a number of checks on the iclog before writing to disk.
3708  *
3709  * 1. Make sure the iclogs are still circular
3710  * 2. Make sure we have a good magic number
3711  * 3. Make sure we don't have magic numbers in the data
3712  * 4. Check fields of each log operation header for:
3713  *      A. Valid client identifier
3714  *      B. tid ptr value falls in valid ptr space (user space code)
3715  *      C. Length in log record header is correct according to the
3716  *              individual operation headers within record.
3717  * 5. When a bwrite will occur within 5 blocks of the front of the physical
3718  *      log, check the preceding blocks of the physical log to make sure all
3719  *      the cycle numbers agree with the current cycle number.
3720  */
3721 STATIC void
3722 xlog_verify_iclog(
3723         struct xlog             *log,
3724         struct xlog_in_core     *iclog,
3725         int                     count)
3726 {
3727         xlog_op_header_t        *ophead;
3728         xlog_in_core_t          *icptr;
3729         xlog_in_core_2_t        *xhdr;
3730         void                    *base_ptr, *ptr, *p;
3731         ptrdiff_t               field_offset;
3732         uint8_t                 clientid;
3733         int                     len, i, j, k, op_len;
3734         int                     idx;
3735
3736         /* check validity of iclog pointers */
3737         spin_lock(&log->l_icloglock);
3738         icptr = log->l_iclog;
3739         for (i = 0; i < log->l_iclog_bufs; i++, icptr = icptr->ic_next)
3740                 ASSERT(icptr);
3741
3742         if (icptr != log->l_iclog)
3743                 xfs_emerg(log->l_mp, "%s: corrupt iclog ring", __func__);
3744         spin_unlock(&log->l_icloglock);
3745
3746         /* check log magic numbers */
3747         if (iclog->ic_header.h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3748                 xfs_emerg(log->l_mp, "%s: invalid magic num", __func__);
3749
3750         base_ptr = ptr = &iclog->ic_header;
3751         p = &iclog->ic_header;
3752         for (ptr += BBSIZE; ptr < base_ptr + count; ptr += BBSIZE) {
3753                 if (*(__be32 *)ptr == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3754                         xfs_emerg(log->l_mp, "%s: unexpected magic num",
3755                                 __func__);
3756         }
3757
3758         /* check fields */
3759         len = be32_to_cpu(iclog->ic_header.h_num_logops);
3760         base_ptr = ptr = iclog->ic_datap;
3761         ophead = ptr;
3762         xhdr = iclog->ic_data;
3763         for (i = 0; i < len; i++) {
3764                 ophead = ptr;
3765
3766                 /* clientid is only 1 byte */
3767                 p = &ophead->oh_clientid;
3768                 field_offset = p - base_ptr;
3769                 if (field_offset & 0x1ff) {
3770                         clientid = ophead->oh_clientid;
3771                 } else {
3772                         idx = BTOBBT((char *)&ophead->oh_clientid - iclog->ic_datap);
3773                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3774                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3775                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3776                                 clientid = xlog_get_client_id(
3777                                         xhdr[j].hic_xheader.xh_cycle_data[k]);
3778                         } else {
3779                                 clientid = xlog_get_client_id(
3780                                         iclog->ic_header.h_cycle_data[idx]);
3781                         }
3782                 }
3783                 if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
3784                         xfs_warn(log->l_mp,
3785                                 "%s: invalid clientid %d op "PTR_FMT" offset 0x%lx",
3786                                 __func__, clientid, ophead,
3787                                 (unsigned long)field_offset);
3788
3789                 /* check length */
3790                 p = &ophead->oh_len;
3791                 field_offset = p - base_ptr;
3792                 if (field_offset & 0x1ff) {
3793                         op_len = be32_to_cpu(ophead->oh_len);
3794                 } else {
3795                         idx = BTOBBT((uintptr_t)&ophead->oh_len -
3796                                     (uintptr_t)iclog->ic_datap);
3797                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3798                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3799                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3800                                 op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
3801                         } else {
3802                                 op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
3803                         }
3804                 }
3805                 ptr += sizeof(xlog_op_header_t) + op_len;
3806         }
3807 }       /* xlog_verify_iclog */
3808 #endif
3809
3810 /*
3811  * Mark all iclogs IOERROR. l_icloglock is held by the caller.
3812  */
3813 STATIC int
3814 xlog_state_ioerror(
3815         struct xlog     *log)
3816 {
3817         xlog_in_core_t  *iclog, *ic;
3818
3819         iclog = log->l_iclog;
3820         if (! (iclog->ic_state & XLOG_STATE_IOERROR)) {
3821                 /*
3822                  * Mark all the incore logs IOERROR.
3823                  * From now on, no log flushes will result.
3824                  */
3825                 ic = iclog;
3826                 do {
3827                         ic->ic_state = XLOG_STATE_IOERROR;
3828                         ic = ic->ic_next;
3829                 } while (ic != iclog);
3830                 return 0;
3831         }
3832         /*
3833          * Return non-zero, if state transition has already happened.
3834          */
3835         return 1;
3836 }
3837
3838 /*
3839  * This is called from xfs_force_shutdown, when we're forcibly
3840  * shutting down the filesystem, typically because of an IO error.
3841  * Our main objectives here are to make sure that:
3842  *      a. if !logerror, flush the logs to disk. Anything modified
3843  *         after this is ignored.
3844  *      b. the filesystem gets marked 'SHUTDOWN' for all interested
3845  *         parties to find out, 'atomically'.
3846  *      c. those who're sleeping on log reservations, pinned objects and
3847  *          other resources get woken up, and be told the bad news.
3848  *      d. nothing new gets queued up after (b) and (c) are done.
3849  *
3850  * Note: for the !logerror case we need to flush the regions held in memory out
3851  * to disk first. This needs to be done before the log is marked as shutdown,
3852  * otherwise the iclog writes will fail.
3853  */
3854 int
3855 xfs_log_force_umount(
3856         struct xfs_mount        *mp,
3857         int                     logerror)
3858 {
3859         struct xlog     *log;
3860         int             retval;
3861
3862         log = mp->m_log;
3863
3864         /*
3865          * If this happens during log recovery, don't worry about
3866          * locking; the log isn't open for business yet.
3867          */
3868         if (!log ||
3869             log->l_flags & XLOG_ACTIVE_RECOVERY) {
3870                 mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3871                 if (mp->m_sb_bp)
3872                         mp->m_sb_bp->b_flags |= XBF_DONE;
3873                 return 0;
3874         }
3875
3876         /*
3877          * Somebody could've already done the hard work for us.
3878          * No need to get locks for this.
3879          */
3880         if (logerror && log->l_iclog->ic_state & XLOG_STATE_IOERROR) {
3881                 ASSERT(XLOG_FORCED_SHUTDOWN(log));
3882                 return 1;
3883         }
3884
3885         /*
3886          * Flush all the completed transactions to disk before marking the log
3887          * being shut down. We need to do it in this order to ensure that
3888          * completed operations are safely on disk before we shut down, and that
3889          * we don't have to issue any buffer IO after the shutdown flags are set
3890          * to guarantee this.
3891          */
3892         if (!logerror)
3893                 xfs_log_force(mp, XFS_LOG_SYNC);
3894
3895         /*
3896          * mark the filesystem and the as in a shutdown state and wake
3897          * everybody up to tell them the bad news.
3898          */
3899         spin_lock(&log->l_icloglock);
3900         mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3901         if (mp->m_sb_bp)
3902                 mp->m_sb_bp->b_flags |= XBF_DONE;
3903
3904         /*
3905          * Mark the log and the iclogs with IO error flags to prevent any
3906          * further log IO from being issued or completed.
3907          */
3908         log->l_flags |= XLOG_IO_ERROR;
3909         retval = xlog_state_ioerror(log);
3910         spin_unlock(&log->l_icloglock);
3911
3912         /*
3913          * We don't want anybody waiting for log reservations after this. That
3914          * means we have to wake up everybody queued up on reserveq as well as
3915          * writeq.  In addition, we make sure in xlog_{re}grant_log_space that
3916          * we don't enqueue anything once the SHUTDOWN flag is set, and this
3917          * action is protected by the grant locks.
3918          */
3919         xlog_grant_head_wake_all(&log->l_reserve_head);
3920         xlog_grant_head_wake_all(&log->l_write_head);
3921
3922         /*
3923          * Wake up everybody waiting on xfs_log_force. Wake the CIL push first
3924          * as if the log writes were completed. The abort handling in the log
3925          * item committed callback functions will do this again under lock to
3926          * avoid races.
3927          */
3928         wake_up_all(&log->l_cilp->xc_commit_wait);
3929         xlog_state_do_callback(log, true, NULL);
3930
3931 #ifdef XFSERRORDEBUG
3932         {
3933                 xlog_in_core_t  *iclog;
3934
3935                 spin_lock(&log->l_icloglock);
3936                 iclog = log->l_iclog;
3937                 do {
3938                         ASSERT(iclog->ic_callback == 0);
3939                         iclog = iclog->ic_next;
3940                 } while (iclog != log->l_iclog);
3941                 spin_unlock(&log->l_icloglock);
3942         }
3943 #endif
3944         /* return non-zero if log IOERROR transition had already happened */
3945         return retval;
3946 }
3947
3948 STATIC int
3949 xlog_iclogs_empty(
3950         struct xlog     *log)
3951 {
3952         xlog_in_core_t  *iclog;
3953
3954         iclog = log->l_iclog;
3955         do {
3956                 /* endianness does not matter here, zero is zero in
3957                  * any language.
3958                  */
3959                 if (iclog->ic_header.h_num_logops)
3960                         return 0;
3961                 iclog = iclog->ic_next;
3962         } while (iclog != log->l_iclog);
3963         return 1;
3964 }
3965
3966 /*
3967  * Verify that an LSN stamped into a piece of metadata is valid. This is
3968  * intended for use in read verifiers on v5 superblocks.
3969  */
3970 bool
3971 xfs_log_check_lsn(
3972         struct xfs_mount        *mp,
3973         xfs_lsn_t               lsn)
3974 {
3975         struct xlog             *log = mp->m_log;
3976         bool                    valid;
3977
3978         /*
3979          * norecovery mode skips mount-time log processing and unconditionally
3980          * resets the in-core LSN. We can't validate in this mode, but
3981          * modifications are not allowed anyways so just return true.
3982          */
3983         if (mp->m_flags & XFS_MOUNT_NORECOVERY)
3984                 return true;
3985
3986         /*
3987          * Some metadata LSNs are initialized to NULL (e.g., the agfl). This is
3988          * handled by recovery and thus safe to ignore here.
3989          */
3990         if (lsn == NULLCOMMITLSN)
3991                 return true;
3992
3993         valid = xlog_valid_lsn(mp->m_log, lsn);
3994
3995         /* warn the user about what's gone wrong before verifier failure */
3996         if (!valid) {
3997                 spin_lock(&log->l_icloglock);
3998                 xfs_warn(mp,
3999 "Corruption warning: Metadata has LSN (%d:%d) ahead of current LSN (%d:%d). "
4000 "Please unmount and run xfs_repair (>= v4.3) to resolve.",
4001                          CYCLE_LSN(lsn), BLOCK_LSN(lsn),
4002                          log->l_curr_cycle, log->l_curr_block);
4003                 spin_unlock(&log->l_icloglock);
4004         }
4005
4006         return valid;
4007 }
4008
4009 bool
4010 xfs_log_in_recovery(
4011         struct xfs_mount        *mp)
4012 {
4013         struct xlog             *log = mp->m_log;
4014
4015         return log->l_flags & XLOG_ACTIVE_RECOVERY;
4016 }