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_log_recover.h"
  20 #include "xfs_inode.h"
  21 #include "xfs_trace.h"
  22 #include "xfs_fsops.h"
  23 #include "xfs_cksum.h"
  24 #include "xfs_sysfs.h"
  25 #include "xfs_sb.h"
  26 #include "xfs_health.h"
  27
  28 kmem_zone_t     *xfs_log_ticket_zone;
  29
  30 /* Local miscellaneous function prototypes */
  31 STATIC int
  32 xlog_commit_record(
  33         struct xlog             *log,
  34         struct xlog_ticket      *ticket,
  35         struct xlog_in_core     **iclog,
  36         xfs_lsn_t               *commitlsnp);
  37
  38 STATIC struct xlog *
  39 xlog_alloc_log(
  40         struct xfs_mount        *mp,
  41         struct xfs_buftarg      *log_target,
  42         xfs_daddr_t             blk_offset,
  43         int                     num_bblks);
  44 STATIC int
  45 xlog_space_left(
  46         struct xlog             *log,
  47         atomic64_t              *head);
  48 STATIC void
  49 xlog_dealloc_log(
  50         struct xlog             *log);
  51
  52 /* local state machine functions */
  53 STATIC void xlog_state_done_syncing(xlog_in_core_t *iclog, int);
  54 STATIC void
  55 xlog_state_do_callback(
  56         struct xlog             *log,
  57         int                     aborted,
  58         struct xlog_in_core     *iclog);
  59 STATIC int
  60 xlog_state_get_iclog_space(
  61         struct xlog             *log,
  62         int                     len,
  63         struct xlog_in_core     **iclog,
  64         struct xlog_ticket      *ticket,
  65         int                     *continued_write,
  66         int                     *logoffsetp);
  67 STATIC int
  68 xlog_state_release_iclog(
  69         struct xlog             *log,
  70         struct xlog_in_core     *iclog);
  71 STATIC void
  72 xlog_state_switch_iclogs(
  73         struct xlog             *log,
  74         struct xlog_in_core     *iclog,
  75         int                     eventual_size);
  76 STATIC void
  77 xlog_state_want_sync(
  78         struct xlog             *log,
  79         struct xlog_in_core     *iclog);
  80
  81 STATIC void
  82 xlog_grant_push_ail(
  83         struct xlog             *log,
  84         int                     need_bytes);
  85 STATIC void
  86 xlog_regrant_reserve_log_space(
  87         struct xlog             *log,
  88         struct xlog_ticket      *ticket);
  89 STATIC void
  90 xlog_ungrant_log_space(
  91         struct xlog             *log,
  92         struct xlog_ticket      *ticket);
  93
  94 #if defined(DEBUG)
  95 STATIC void
  96 xlog_verify_dest_ptr(
  97         struct xlog             *log,
  98         void                    *ptr);
  99 STATIC void
 100 xlog_verify_grant_tail(
 101         struct xlog *log);
 102 STATIC void
 103 xlog_verify_iclog(
 104         struct xlog             *log,
 105         struct xlog_in_core     *iclog,
 106         int                     count,
 107         bool                    syncing);
 108 STATIC void
 109 xlog_verify_tail_lsn(
 110         struct xlog             *log,
 111         struct xlog_in_core     *iclog,
 112         xfs_lsn_t               tail_lsn);
 113 #else
 114 #define xlog_verify_dest_ptr(a,b)
 115 #define xlog_verify_grant_tail(a)
 116 #define xlog_verify_iclog(a,b,c,d)
 117 #define xlog_verify_tail_lsn(a,b,c)
 118 #endif
 119
 120 STATIC int
 121 xlog_iclogs_empty(
 122         struct xlog             *log);
 123
 124 static void
 125 xlog_grant_sub_space(
 126         struct xlog             *log,
 127         atomic64_t              *head,
 128         int                     bytes)
 129 {
 130         int64_t head_val = atomic64_read(head);
 131         int64_t new, old;
 132
 133         do {
 134                 int     cycle, space;
 135
 136                 xlog_crack_grant_head_val(head_val, &cycle, &space);
 137
 138                 space -= bytes;
 139                 if (space < 0) {
 140                         space += log->l_logsize;
 141                         cycle--;
 142                 }
 143
 144                 old = head_val;
 145                 new = xlog_assign_grant_head_val(cycle, space);
 146                 head_val = atomic64_cmpxchg(head, old, new);
 147         } while (head_val != old);
 148 }
 149
 150 static void
 151 xlog_grant_add_space(
 152         struct xlog             *log,
 153         atomic64_t              *head,
 154         int                     bytes)
 155 {
 156         int64_t head_val = atomic64_read(head);
 157         int64_t new, old;
 158
 159         do {
 160                 int             tmp;
 161                 int             cycle, space;
 162
 163                 xlog_crack_grant_head_val(head_val, &cycle, &space);
 164
 165                 tmp = log->l_logsize - space;
 166                 if (tmp > bytes)
 167                         space += bytes;
 168                 else {
 169                         space = bytes - tmp;
 170                         cycle++;
 171                 }
 172
 173                 old = head_val;
 174                 new = xlog_assign_grant_head_val(cycle, space);
 175                 head_val = atomic64_cmpxchg(head, old, new);
 176         } while (head_val != old);
 177 }
 178
 179 STATIC void
 180 xlog_grant_head_init(
 181         struct xlog_grant_head  *head)
 182 {
 183         xlog_assign_grant_head(&head->grant, 1, 0);
 184         INIT_LIST_HEAD(&head->waiters);
 185         spin_lock_init(&head->lock);
 186 }
 187
 188 STATIC void
 189 xlog_grant_head_wake_all(
 190         struct xlog_grant_head  *head)
 191 {
 192         struct xlog_ticket      *tic;
 193
 194         spin_lock(&head->lock);
 195         list_for_each_entry(tic, &head->waiters, t_queue)
 196                 wake_up_process(tic->t_task);
 197         spin_unlock(&head->lock);
 198 }
 199
 200 static inline int
 201 xlog_ticket_reservation(
 202         struct xlog             *log,
 203         struct xlog_grant_head  *head,
 204         struct xlog_ticket      *tic)
 205 {
 206         if (head == &log->l_write_head) {
 207                 ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
 208                 return tic->t_unit_res;
 209         } else {
 210                 if (tic->t_flags & XLOG_TIC_PERM_RESERV)
 211                         return tic->t_unit_res * tic->t_cnt;
 212                 else
 213                         return tic->t_unit_res;
 214         }
 215 }
 216
 217 STATIC bool
 218 xlog_grant_head_wake(
 219         struct xlog             *log,
 220         struct xlog_grant_head  *head,
 221         int                     *free_bytes)
 222 {
 223         struct xlog_ticket      *tic;
 224         int                     need_bytes;
 225
 226         list_for_each_entry(tic, &head->waiters, t_queue) {
 227                 need_bytes = xlog_ticket_reservation(log, head, tic);
 228                 if (*free_bytes < need_bytes)
 229                         return false;
 230
 231                 *free_bytes -= need_bytes;
 232                 trace_xfs_log_grant_wake_up(log, tic);
 233                 wake_up_process(tic->t_task);
 234         }
 235
 236         return true;
 237 }
 238
 239 STATIC int
 240 xlog_grant_head_wait(
 241         struct xlog             *log,
 242         struct xlog_grant_head  *head,
 243         struct xlog_ticket      *tic,
 244         int                     need_bytes) __releases(&head->lock)
 245                                             __acquires(&head->lock)
 246 {
 247         list_add_tail(&tic->t_queue, &head->waiters);
 248
 249         do {
 250                 if (XLOG_FORCED_SHUTDOWN(log))
 251                         goto shutdown;
 252                 xlog_grant_push_ail(log, need_bytes);
 253
 254                 __set_current_state(TASK_UNINTERRUPTIBLE);
 255                 spin_unlock(&head->lock);
 256
 257                 XFS_STATS_INC(log->l_mp, xs_sleep_logspace);
 258
 259                 trace_xfs_log_grant_sleep(log, tic);
 260                 schedule();
 261                 trace_xfs_log_grant_wake(log, tic);
 262
 263                 spin_lock(&head->lock);
 264                 if (XLOG_FORCED_SHUTDOWN(log))
 265                         goto shutdown;
 266         } while (xlog_space_left(log, &head->grant) < need_bytes);
 267
 268         list_del_init(&tic->t_queue);
 269         return 0;
 270 shutdown:
 271         list_del_init(&tic->t_queue);
 272         return -EIO;
 273 }
 274
 275 /*
 276  * Atomically get the log space required for a log ticket.
 277  *
 278  * Once a ticket gets put onto head->waiters, it will only return after the
 279  * needed reservation is satisfied.
 280  *
 281  * This function is structured so that it has a lock free fast path. This is
 282  * necessary because every new transaction reservation will come through this
 283  * path. Hence any lock will be globally hot if we take it unconditionally on
 284  * every pass.
 285  *
 286  * As tickets are only ever moved on and off head->waiters under head->lock, we
 287  * only need to take that lock if we are going to add the ticket to the queue
 288  * and sleep. We can avoid taking the lock if the ticket was never added to
 289  * head->waiters because the t_queue list head will be empty and we hold the
 290  * only reference to it so it can safely be checked unlocked.
 291  */
 292 STATIC int
 293 xlog_grant_head_check(
 294         struct xlog             *log,
 295         struct xlog_grant_head  *head,
 296         struct xlog_ticket      *tic,
 297         int                     *need_bytes)
 298 {
 299         int                     free_bytes;
 300         int                     error = 0;
 301
 302         ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
 303
 304         /*
 305          * If there are other waiters on the queue then give them a chance at
 306          * logspace before us.  Wake up the first waiters, if we do not wake
 307          * up all the waiters then go to sleep waiting for more free space,
 308          * otherwise try to get some space for this transaction.
 309          */
 310         *need_bytes = xlog_ticket_reservation(log, head, tic);
 311         free_bytes = xlog_space_left(log, &head->grant);
 312         if (!list_empty_careful(&head->waiters)) {
 313                 spin_lock(&head->lock);
 314                 if (!xlog_grant_head_wake(log, head, &free_bytes) ||
 315                     free_bytes < *need_bytes) {
 316                         error = xlog_grant_head_wait(log, head, tic,
 317                                                      *need_bytes);
 318                 }
 319                 spin_unlock(&head->lock);
 320         } else if (free_bytes < *need_bytes) {
 321                 spin_lock(&head->lock);
 322                 error = xlog_grant_head_wait(log, head, tic, *need_bytes);
 323                 spin_unlock(&head->lock);
 324         }
 325
 326         return error;
 327 }
 328
 329 static void
 330 xlog_tic_reset_res(xlog_ticket_t *tic)
 331 {
 332         tic->t_res_num = 0;
 333         tic->t_res_arr_sum = 0;
 334         tic->t_res_num_ophdrs = 0;
 335 }
 336
 337 static void
 338 xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type)
 339 {
 340         if (tic->t_res_num == XLOG_TIC_LEN_MAX) {
 341                 /* add to overflow and start again */
 342                 tic->t_res_o_flow += tic->t_res_arr_sum;
 343                 tic->t_res_num = 0;
 344                 tic->t_res_arr_sum = 0;
 345         }
 346
 347         tic->t_res_arr[tic->t_res_num].r_len = len;
 348         tic->t_res_arr[tic->t_res_num].r_type = type;
 349         tic->t_res_arr_sum += len;
 350         tic->t_res_num++;
 351 }
 352
 353 /*
 354  * Replenish the byte reservation required by moving the grant write head.
 355  */
 356 int
 357 xfs_log_regrant(
 358         struct xfs_mount        *mp,
 359         struct xlog_ticket      *tic)
 360 {
 361         struct xlog             *log = mp->m_log;
 362         int                     need_bytes;
 363         int                     error = 0;
 364
 365         if (XLOG_FORCED_SHUTDOWN(log))
 366                 return -EIO;
 367
 368         XFS_STATS_INC(mp, xs_try_logspace);
 369
 370         /*
 371          * This is a new transaction on the ticket, so we need to change the
 372          * transaction ID so that the next transaction has a different TID in
 373          * the log. Just add one to the existing tid so that we can see chains
 374          * of rolling transactions in the log easily.
 375          */
 376         tic->t_tid++;
 377
 378         xlog_grant_push_ail(log, tic->t_unit_res);
 379
 380         tic->t_curr_res = tic->t_unit_res;
 381         xlog_tic_reset_res(tic);
 382
 383         if (tic->t_cnt > 0)
 384                 return 0;
 385
 386         trace_xfs_log_regrant(log, tic);
 387
 388         error = xlog_grant_head_check(log, &log->l_write_head, tic,
 389                                       &need_bytes);
 390         if (error)
 391                 goto out_error;
 392
 393         xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
 394         trace_xfs_log_regrant_exit(log, tic);
 395         xlog_verify_grant_tail(log);
 396         return 0;
 397
 398 out_error:
 399         /*
 400          * If we are failing, make sure the ticket doesn't have any current
 401          * reservations.  We don't want to add this back when the ticket/
 402          * transaction gets cancelled.
 403          */
 404         tic->t_curr_res = 0;
 405         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
 406         return error;
 407 }
 408
 409 /*
 410  * Reserve log space and return a ticket corresponding to the reservation.
 411  *
 412  * Each reservation is going to reserve extra space for a log record header.
 413  * When writes happen to the on-disk log, we don't subtract the length of the
 414  * log record header from any reservation.  By wasting space in each
 415  * reservation, we prevent over allocation problems.
 416  */
 417 int
 418 xfs_log_reserve(
 419         struct xfs_mount        *mp,
 420         int                     unit_bytes,
 421         int                     cnt,
 422         struct xlog_ticket      **ticp,
 423         uint8_t                 client,
 424         bool                    permanent)
 425 {
 426         struct xlog             *log = mp->m_log;
 427         struct xlog_ticket      *tic;
 428         int                     need_bytes;
 429         int                     error = 0;
 430
 431         ASSERT(client == XFS_TRANSACTION || client == XFS_LOG);
 432
 433         if (XLOG_FORCED_SHUTDOWN(log))
 434                 return -EIO;
 435
 436         XFS_STATS_INC(mp, xs_try_logspace);
 437
 438         ASSERT(*ticp == NULL);
 439         tic = xlog_ticket_alloc(log, unit_bytes, cnt, client, permanent,
 440                                 KM_SLEEP | KM_MAYFAIL);
 441         if (!tic)
 442                 return -ENOMEM;
 443
 444         *ticp = tic;
 445
 446         xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt
 447                                             : tic->t_unit_res);
 448
 449         trace_xfs_log_reserve(log, tic);
 450
 451         error = xlog_grant_head_check(log, &log->l_reserve_head, tic,
 452                                       &need_bytes);
 453         if (error)
 454                 goto out_error;
 455
 456         xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes);
 457         xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
 458         trace_xfs_log_reserve_exit(log, tic);
 459         xlog_verify_grant_tail(log);
 460         return 0;
 461
 462 out_error:
 463         /*
 464          * If we are failing, make sure the ticket doesn't have any current
 465          * reservations.  We don't want to add this back when the ticket/
 466          * transaction gets cancelled.
 467          */
 468         tic->t_curr_res = 0;
 469         tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
 470         return error;
 471 }
 472
 473
 474 /*
 475  * NOTES:
 476  *
 477  *      1. currblock field gets updated at startup and after in-core logs
 478  *              marked as with WANT_SYNC.
 479  */
 480
 481 /*
 482  * This routine is called when a user of a log manager ticket is done with
 483  * the reservation.  If the ticket was ever used, then a commit record for
 484  * the associated transaction is written out as a log operation header with
 485  * no data.  The flag XLOG_TIC_INITED is set when the first write occurs with
 486  * a given ticket.  If the ticket was one with a permanent reservation, then
 487  * a few operations are done differently.  Permanent reservation tickets by
 488  * default don't release the reservation.  They just commit the current
 489  * transaction with the belief that the reservation is still needed.  A flag
 490  * must be passed in before permanent reservations are actually released.
 491  * When these type of tickets are not released, they need to be set into
 492  * the inited state again.  By doing this, a start record will be written
 493  * out when the next write occurs.
 494  */
 495 xfs_lsn_t
 496 xfs_log_done(
 497         struct xfs_mount        *mp,
 498         struct xlog_ticket      *ticket,
 499         struct xlog_in_core     **iclog,
 500         bool                    regrant)
 501 {
 502         struct xlog             *log = mp->m_log;
 503         xfs_lsn_t               lsn = 0;
 504
 505         if (XLOG_FORCED_SHUTDOWN(log) ||
 506             /*
 507              * If nothing was ever written, don't write out commit record.
 508              * If we get an error, just continue and give back the log ticket.
 509              */
 510             (((ticket->t_flags & XLOG_TIC_INITED) == 0) &&
 511              (xlog_commit_record(log, ticket, iclog, &lsn)))) {
 512                 lsn = (xfs_lsn_t) -1;
 513                 regrant = false;
 514         }
 515
 516
 517         if (!regrant) {
 518                 trace_xfs_log_done_nonperm(log, ticket);
 519
 520                 /*
 521                  * Release ticket if not permanent reservation or a specific
 522                  * request has been made to release a permanent reservation.
 523                  */
 524                 xlog_ungrant_log_space(log, ticket);
 525         } else {
 526                 trace_xfs_log_done_perm(log, ticket);
 527
 528                 xlog_regrant_reserve_log_space(log, ticket);
 529                 /* If this ticket was a permanent reservation and we aren't
 530                  * trying to release it, reset the inited flags; so next time
 531                  * we write, a start record will be written out.
 532                  */
 533                 ticket->t_flags |= XLOG_TIC_INITED;
 534         }
 535
 536         xfs_log_ticket_put(ticket);
 537         return lsn;
 538 }
 539
 540 /*
 541  * Attaches a new iclog I/O completion callback routine during
 542  * transaction commit.  If the log is in error state, a non-zero
 543  * return code is handed back and the caller is responsible for
 544  * executing the callback at an appropriate time.
 545  */
 546 int
 547 xfs_log_notify(
 548         struct xlog_in_core     *iclog,
 549         xfs_log_callback_t      *cb)
 550 {
 551         int     abortflg;
 552
 553         spin_lock(&iclog->ic_callback_lock);
 554         abortflg = (iclog->ic_state & XLOG_STATE_IOERROR);
 555         if (!abortflg) {
 556                 ASSERT_ALWAYS((iclog->ic_state == XLOG_STATE_ACTIVE) ||
 557                               (iclog->ic_state == XLOG_STATE_WANT_SYNC));
 558                 cb->cb_next = NULL;
 559                 *(iclog->ic_callback_tail) = cb;
 560                 iclog->ic_callback_tail = &(cb->cb_next);
 561         }
 562         spin_unlock(&iclog->ic_callback_lock);
 563         return abortflg;
 564 }
 565
 566 int
 567 xfs_log_release_iclog(
 568         struct xfs_mount        *mp,
 569         struct xlog_in_core     *iclog)
 570 {
 571         if (xlog_state_release_iclog(mp->m_log, iclog)) {
 572                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
 573                 return -EIO;
 574         }
 575
 576         return 0;
 577 }
 578
 579 /*
 580  * Mount a log filesystem
 581  *
 582  * mp           - ubiquitous xfs mount point structure
 583  * log_target   - buftarg of on-disk log device
 584  * blk_offset   - Start block # where block size is 512 bytes (BBSIZE)
 585  * num_bblocks  - Number of BBSIZE blocks in on-disk log
 586  *
 587  * Return error or zero.
 588  */
 589 int
 590 xfs_log_mount(
 591         xfs_mount_t     *mp,
 592         xfs_buftarg_t   *log_target,
 593         xfs_daddr_t     blk_offset,
 594         int             num_bblks)
 595 {
 596         bool            fatal = xfs_sb_version_hascrc(&mp->m_sb);
 597         int             error = 0;
 598         int             min_logfsbs;
 599
 600         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
 601                 xfs_notice(mp, "Mounting V%d Filesystem",
 602                            XFS_SB_VERSION_NUM(&mp->m_sb));
 603         } else {
 604                 xfs_notice(mp,
 605 "Mounting V%d filesystem in no-recovery mode. Filesystem will be inconsistent.",
 606                            XFS_SB_VERSION_NUM(&mp->m_sb));
 607                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 608         }
 609
 610         mp->m_log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
 611         if (IS_ERR(mp->m_log)) {
 612                 error = PTR_ERR(mp->m_log);
 613                 goto out;
 614         }
 615
 616         /*
 617          * Validate the given log space and drop a critical message via syslog
 618          * if the log size is too small that would lead to some unexpected
 619          * situations in transaction log space reservation stage.
 620          *
 621          * Note: we can't just reject the mount if the validation fails.  This
 622          * would mean that people would have to downgrade their kernel just to
 623          * remedy the situation as there is no way to grow the log (short of
 624          * black magic surgery with xfs_db).
 625          *
 626          * We can, however, reject mounts for CRC format filesystems, as the
 627          * mkfs binary being used to make the filesystem should never create a
 628          * filesystem with a log that is too small.
 629          */
 630         min_logfsbs = xfs_log_calc_minimum_size(mp);
 631
 632         if (mp->m_sb.sb_logblocks < min_logfsbs) {
 633                 xfs_warn(mp,
 634                 "Log size %d blocks too small, minimum size is %d blocks",
 635                          mp->m_sb.sb_logblocks, min_logfsbs);
 636                 error = -EINVAL;
 637         } else if (mp->m_sb.sb_logblocks > XFS_MAX_LOG_BLOCKS) {
 638                 xfs_warn(mp,
 639                 "Log size %d blocks too large, maximum size is %lld blocks",
 640                          mp->m_sb.sb_logblocks, XFS_MAX_LOG_BLOCKS);
 641                 error = -EINVAL;
 642         } else if (XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks) > XFS_MAX_LOG_BYTES) {
 643                 xfs_warn(mp,
 644                 "log size %lld bytes too large, maximum size is %lld bytes",
 645                          XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks),
 646                          XFS_MAX_LOG_BYTES);
 647                 error = -EINVAL;
 648         } else if (mp->m_sb.sb_logsunit > 1 &&
 649                    mp->m_sb.sb_logsunit % mp->m_sb.sb_blocksize) {
 650                 xfs_warn(mp,
 651                 "log stripe unit %u bytes must be a multiple of block size",
 652                          mp->m_sb.sb_logsunit);
 653                 error = -EINVAL;
 654                 fatal = true;
 655         }
 656         if (error) {
 657                 /*
 658                  * Log check errors are always fatal on v5; or whenever bad
 659                  * metadata leads to a crash.
 660                  */
 661                 if (fatal) {
 662                         xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
 663                         ASSERT(0);
 664                         goto out_free_log;
 665                 }
 666                 xfs_crit(mp, "Log size out of supported range.");
 667                 xfs_crit(mp,
 668 "Continuing onwards, but if log hangs are experienced then please report this message in the bug report.");
 669         }
 670
 671         /*
 672          * Initialize the AIL now we have a log.
 673          */
 674         error = xfs_trans_ail_init(mp);
 675         if (error) {
 676                 xfs_warn(mp, "AIL initialisation failed: error %d", error);
 677                 goto out_free_log;
 678         }
 679         mp->m_log->l_ailp = mp->m_ail;
 680
 681         /*
 682          * skip log recovery on a norecovery mount.  pretend it all
 683          * just worked.
 684          */
 685         if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
 686                 int     readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
 687
 688                 if (readonly)
 689                         mp->m_flags &= ~XFS_MOUNT_RDONLY;
 690
 691                 error = xlog_recover(mp->m_log);
 692
 693                 if (readonly)
 694                         mp->m_flags |= XFS_MOUNT_RDONLY;
 695                 if (error) {
 696                         xfs_warn(mp, "log mount/recovery failed: error %d",
 697                                 error);
 698                         xlog_recover_cancel(mp->m_log);
 699                         goto out_destroy_ail;
 700                 }
 701         }
 702
 703         error = xfs_sysfs_init(&mp->m_log->l_kobj, &xfs_log_ktype, &mp->m_kobj,
 704                                "log");
 705         if (error)
 706                 goto out_destroy_ail;
 707
 708         /* Normal transactions can now occur */
 709         mp->m_log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
 710
 711         /*
 712          * Now the log has been fully initialised and we know were our
 713          * space grant counters are, we can initialise the permanent ticket
 714          * needed for delayed logging to work.
 715          */
 716         xlog_cil_init_post_recovery(mp->m_log);
 717
 718         return 0;
 719
 720 out_destroy_ail:
 721         xfs_trans_ail_destroy(mp);
 722 out_free_log:
 723         xlog_dealloc_log(mp->m_log);
 724 out:
 725         return error;
 726 }
 727
 728 /*
 729  * Finish the recovery of the file system.  This is separate from the
 730  * xfs_log_mount() call, because it depends on the code in xfs_mountfs() to read
 731  * in the root and real-time bitmap inodes between calling xfs_log_mount() and
 732  * here.
 733  *
 734  * If we finish recovery successfully, start the background log work. If we are
 735  * not doing recovery, then we have a RO filesystem and we don't need to start
 736  * it.
 737  */
 738 int
 739 xfs_log_mount_finish(
 740         struct xfs_mount        *mp)
 741 {
 742         int     error = 0;
 743         bool    readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
 744         bool    recovered = mp->m_log->l_flags & XLOG_RECOVERY_NEEDED;
 745
 746         if (mp->m_flags & XFS_MOUNT_NORECOVERY) {
 747                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 748                 return 0;
 749         } else if (readonly) {
 750                 /* Allow unlinked processing to proceed */
 751                 mp->m_flags &= ~XFS_MOUNT_RDONLY;
 752         }
 753
 754         /*
 755          * During the second phase of log recovery, we need iget and
 756          * iput to behave like they do for an active filesystem.
 757          * xfs_fs_drop_inode needs to be able to prevent the deletion
 758          * of inodes before we're done replaying log items on those
 759          * inodes.  Turn it off immediately after recovery finishes
 760          * so that we don't leak the quota inodes if subsequent mount
 761          * activities fail.
 762          *
 763          * We let all inodes involved in redo item processing end up on
 764          * the LRU instead of being evicted immediately so that if we do
 765          * something to an unlinked inode, the irele won't cause
 766          * premature truncation and freeing of the inode, which results
 767          * in log recovery failure.  We have to evict the unreferenced
 768          * lru inodes after clearing SB_ACTIVE because we don't
 769          * otherwise clean up the lru if there's a subsequent failure in
 770          * xfs_mountfs, which leads to us leaking the inodes if nothing
 771          * else (e.g. quotacheck) references the inodes before the
 772          * mount failure occurs.
 773          */
 774         mp->m_super->s_flags |= SB_ACTIVE;
 775         error = xlog_recover_finish(mp->m_log);
 776         if (!error)
 777                 xfs_log_work_queue(mp);
 778         mp->m_super->s_flags &= ~SB_ACTIVE;
 779         evict_inodes(mp->m_super);
 780
 781         /*
 782          * Drain the buffer LRU after log recovery. This is required for v4
 783          * filesystems to avoid leaving around buffers with NULL verifier ops,
 784          * but we do it unconditionally to make sure we're always in a clean
 785          * cache state after mount.
 786          *
 787          * Don't push in the error case because the AIL may have pending intents
 788          * that aren't removed until recovery is cancelled.
 789          */
 790         if (!error && recovered) {
 791                 xfs_log_force(mp, XFS_LOG_SYNC);
 792                 xfs_ail_push_all_sync(mp->m_ail);
 793         }
 794         xfs_wait_buftarg(mp->m_ddev_targp);
 795
 796         if (readonly)
 797                 mp->m_flags |= XFS_MOUNT_RDONLY;
 798
 799         return error;
 800 }
 801
 802 /*
 803  * The mount has failed. Cancel the recovery if it hasn't completed and destroy
 804  * the log.
 805  */
 806 int
 807 xfs_log_mount_cancel(
 808         struct xfs_mount        *mp)
 809 {
 810         int                     error;
 811
 812         error = xlog_recover_cancel(mp->m_log);
 813         xfs_log_unmount(mp);
 814
 815         return error;
 816 }
 817
 818 /*
 819  * Final log writes as part of unmount.
 820  *
 821  * Mark the filesystem clean as unmount happens.  Note that during relocation
 822  * this routine needs to be executed as part of source-bag while the
 823  * deallocation must not be done until source-end.
 824  */
 825
 826 /* Actually write the unmount record to disk. */
 827 static void
 828 xfs_log_write_unmount_record(
 829         struct xfs_mount        *mp)
 830 {
 831         /* the data section must be 32 bit size aligned */
 832         struct xfs_unmount_log_format magic = {
 833                 .magic = XLOG_UNMOUNT_TYPE,
 834         };
 835         struct xfs_log_iovec reg = {
 836                 .i_addr = &magic,
 837                 .i_len = sizeof(magic),
 838                 .i_type = XLOG_REG_TYPE_UNMOUNT,
 839         };
 840         struct xfs_log_vec vec = {
 841                 .lv_niovecs = 1,
 842                 .lv_iovecp = &reg,
 843         };
 844         struct xlog             *log = mp->m_log;
 845         struct xlog_in_core     *iclog;
 846         struct xlog_ticket      *tic = NULL;
 847         xfs_lsn_t               lsn;
 848         uint                    flags = XLOG_UNMOUNT_TRANS;
 849         int                     error;
 850
 851         error = xfs_log_reserve(mp, 600, 1, &tic, XFS_LOG, 0);
 852         if (error)
 853                 goto out_err;
 854
 855         /*
 856          * If we think the summary counters are bad, clear the unmount header
 857          * flag in the unmount record so that the summary counters will be
 858          * recalculated during log recovery at next mount.  Refer to
 859          * xlog_check_unmount_rec for more details.
 860          */
 861         if (XFS_TEST_ERROR(xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS), mp,
 862                         XFS_ERRTAG_FORCE_SUMMARY_RECALC)) {
 863                 xfs_alert(mp, "%s: will fix summary counters at next mount",
 864                                 __func__);
 865                 flags &= ~XLOG_UNMOUNT_TRANS;
 866         }
 867
 868         /* remove inited flag, and account for space used */
 869         tic->t_flags = 0;
 870         tic->t_curr_res -= sizeof(magic);
 871         error = xlog_write(log, &vec, tic, &lsn, NULL, flags);
 872         /*
 873          * At this point, we're umounting anyway, so there's no point in
 874          * transitioning log state to IOERROR. Just continue...
 875          */
 876 out_err:
 877         if (error)
 878                 xfs_alert(mp, "%s: unmount record failed", __func__);
 879
 880         spin_lock(&log->l_icloglock);
 881         iclog = log->l_iclog;
 882         atomic_inc(&iclog->ic_refcnt);
 883         xlog_state_want_sync(log, iclog);
 884         spin_unlock(&log->l_icloglock);
 885         error = xlog_state_release_iclog(log, iclog);
 886
 887         spin_lock(&log->l_icloglock);
 888         switch (iclog->ic_state) {
 889         default:
 890                 if (!XLOG_FORCED_SHUTDOWN(log)) {
 891                         xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
 892                         break;
 893                 }
 894                 /* fall through */
 895         case XLOG_STATE_ACTIVE:
 896         case XLOG_STATE_DIRTY:
 897                 spin_unlock(&log->l_icloglock);
 898                 break;
 899         }
 900
 901         if (tic) {
 902                 trace_xfs_log_umount_write(log, tic);
 903                 xlog_ungrant_log_space(log, tic);
 904                 xfs_log_ticket_put(tic);
 905         }
 906 }
 907
 908 /*
 909  * Unmount record used to have a string "Unmount filesystem--" in the
 910  * data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
 911  * We just write the magic number now since that particular field isn't
 912  * currently architecture converted and "Unmount" is a bit foo.
 913  * As far as I know, there weren't any dependencies on the old behaviour.
 914  */
 915
 916 static int
 917 xfs_log_unmount_write(xfs_mount_t *mp)
 918 {
 919         struct xlog      *log = mp->m_log;
 920         xlog_in_core_t   *iclog;
 921 #ifdef DEBUG
 922         xlog_in_core_t   *first_iclog;
 923 #endif
 924         int              error;
 925
 926         /*
 927          * Don't write out unmount record on norecovery mounts or ro devices.
 928          * Or, if we are doing a forced umount (typically because of IO errors).
 929          */
 930         if (mp->m_flags & XFS_MOUNT_NORECOVERY ||
 931             xfs_readonly_buftarg(log->l_mp->m_logdev_targp)) {
 932                 ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 933                 return 0;
 934         }
 935
 936         error = xfs_log_force(mp, XFS_LOG_SYNC);
 937         ASSERT(error || !(XLOG_FORCED_SHUTDOWN(log)));
 938
 939 #ifdef DEBUG
 940         first_iclog = iclog = log->l_iclog;
 941         do {
 942                 if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
 943                         ASSERT(iclog->ic_state & XLOG_STATE_ACTIVE);
 944                         ASSERT(iclog->ic_offset == 0);
 945                 }
 946                 iclog = iclog->ic_next;
 947         } while (iclog != first_iclog);
 948 #endif
 949         if (! (XLOG_FORCED_SHUTDOWN(log))) {
 950                 xfs_log_write_unmount_record(mp);
 951         } else {
 952                 /*
 953                  * We're already in forced_shutdown mode, couldn't
 954                  * even attempt to write out the unmount transaction.
 955                  *
 956                  * Go through the motions of sync'ing and releasing
 957                  * the iclog, even though no I/O will actually happen,
 958                  * we need to wait for other log I/Os that may already
 959                  * be in progress.  Do this as a separate section of
 960                  * code so we'll know if we ever get stuck here that
 961                  * we're in this odd situation of trying to unmount
 962                  * a file system that went into forced_shutdown as
 963                  * the result of an unmount..
 964                  */
 965                 spin_lock(&log->l_icloglock);
 966                 iclog = log->l_iclog;
 967                 atomic_inc(&iclog->ic_refcnt);
 968
 969                 xlog_state_want_sync(log, iclog);
 970                 spin_unlock(&log->l_icloglock);
 971                 error =  xlog_state_release_iclog(log, iclog);
 972
 973                 spin_lock(&log->l_icloglock);
 974
 975                 if ( ! (   iclog->ic_state == XLOG_STATE_ACTIVE
 976                         || iclog->ic_state == XLOG_STATE_DIRTY
 977                         || iclog->ic_state == XLOG_STATE_IOERROR) ) {
 978
 979                                 xlog_wait(&iclog->ic_force_wait,
 980                                                         &log->l_icloglock);
 981                 } else {
 982                         spin_unlock(&log->l_icloglock);
 983                 }
 984         }
 985
 986         return error;
 987 }       /* xfs_log_unmount_write */
 988
 989 /*
 990  * Empty the log for unmount/freeze.
 991  *
 992  * To do this, we first need to shut down the background log work so it is not
 993  * trying to cover the log as we clean up. We then need to unpin all objects in
 994  * the log so we can then flush them out. Once they have completed their IO and
 995  * run the callbacks removing themselves from the AIL, we can write the unmount
 996  * record.
 997  */
 998 void
 999 xfs_log_quiesce(
1000         struct xfs_mount        *mp)
1001 {
1002         cancel_delayed_work_sync(&mp->m_log->l_work);
1003         xfs_log_force(mp, XFS_LOG_SYNC);
1004
1005         /*
1006          * The superblock buffer is uncached and while xfs_ail_push_all_sync()
1007          * will push it, xfs_wait_buftarg() will not wait for it. Further,
1008          * xfs_buf_iowait() cannot be used because it was pushed with the
1009          * XBF_ASYNC flag set, so we need to use a lock/unlock pair to wait for
1010          * the IO to complete.
1011          */
1012         xfs_ail_push_all_sync(mp->m_ail);
1013         xfs_wait_buftarg(mp->m_ddev_targp);
1014         xfs_buf_lock(mp->m_sb_bp);
1015         xfs_buf_unlock(mp->m_sb_bp);
1016
1017         xfs_log_unmount_write(mp);
1018 }
1019
1020 /*
1021  * Shut down and release the AIL and Log.
1022  *
1023  * During unmount, we need to ensure we flush all the dirty metadata objects
1024  * from the AIL so that the log is empty before we write the unmount record to
1025  * the log. Once this is done, we can tear down the AIL and the log.
1026  */
1027 void
1028 xfs_log_unmount(
1029         struct xfs_mount        *mp)
1030 {
1031         xfs_log_quiesce(mp);
1032
1033         xfs_trans_ail_destroy(mp);
1034
1035         xfs_sysfs_del(&mp->m_log->l_kobj);
1036
1037         xlog_dealloc_log(mp->m_log);
1038 }
1039
1040 void
1041 xfs_log_item_init(
1042         struct xfs_mount        *mp,
1043         struct xfs_log_item     *item,
1044         int                     type,
1045         const struct xfs_item_ops *ops)
1046 {
1047         item->li_mountp = mp;
1048         item->li_ailp = mp->m_ail;
1049         item->li_type = type;
1050         item->li_ops = ops;
1051         item->li_lv = NULL;
1052
1053         INIT_LIST_HEAD(&item->li_ail);
1054         INIT_LIST_HEAD(&item->li_cil);
1055         INIT_LIST_HEAD(&item->li_bio_list);
1056         INIT_LIST_HEAD(&item->li_trans);
1057 }
1058
1059 /*
1060  * Wake up processes waiting for log space after we have moved the log tail.
1061  */
1062 void
1063 xfs_log_space_wake(
1064         struct xfs_mount        *mp)
1065 {
1066         struct xlog             *log = mp->m_log;
1067         int                     free_bytes;
1068
1069         if (XLOG_FORCED_SHUTDOWN(log))
1070                 return;
1071
1072         if (!list_empty_careful(&log->l_write_head.waiters)) {
1073                 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
1074
1075                 spin_lock(&log->l_write_head.lock);
1076                 free_bytes = xlog_space_left(log, &log->l_write_head.grant);
1077                 xlog_grant_head_wake(log, &log->l_write_head, &free_bytes);
1078                 spin_unlock(&log->l_write_head.lock);
1079         }
1080
1081         if (!list_empty_careful(&log->l_reserve_head.waiters)) {
1082                 ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
1083
1084                 spin_lock(&log->l_reserve_head.lock);
1085                 free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1086                 xlog_grant_head_wake(log, &log->l_reserve_head, &free_bytes);
1087                 spin_unlock(&log->l_reserve_head.lock);
1088         }
1089 }
1090
1091 /*
1092  * Determine if we have a transaction that has gone to disk that needs to be
1093  * covered. To begin the transition to the idle state firstly the log needs to
1094  * be idle. That means the CIL, the AIL and the iclogs needs to be empty before
1095  * we start attempting to cover the log.
1096  *
1097  * Only if we are then in a state where covering is needed, the caller is
1098  * informed that dummy transactions are required to move the log into the idle
1099  * state.
1100  *
1101  * If there are any items in the AIl or CIL, then we do not want to attempt to
1102  * cover the log as we may be in a situation where there isn't log space
1103  * available to run a dummy transaction and this can lead to deadlocks when the
1104  * tail of the log is pinned by an item that is modified in the CIL.  Hence
1105  * there's no point in running a dummy transaction at this point because we
1106  * can't start trying to idle the log until both the CIL and AIL are empty.
1107  */
1108 static int
1109 xfs_log_need_covered(xfs_mount_t *mp)
1110 {
1111         struct xlog     *log = mp->m_log;
1112         int             needed = 0;
1113
1114         if (!xfs_fs_writable(mp, SB_FREEZE_WRITE))
1115                 return 0;
1116
1117         if (!xlog_cil_empty(log))
1118                 return 0;
1119
1120         spin_lock(&log->l_icloglock);
1121         switch (log->l_covered_state) {
1122         case XLOG_STATE_COVER_DONE:
1123         case XLOG_STATE_COVER_DONE2:
1124         case XLOG_STATE_COVER_IDLE:
1125                 break;
1126         case XLOG_STATE_COVER_NEED:
1127         case XLOG_STATE_COVER_NEED2:
1128                 if (xfs_ail_min_lsn(log->l_ailp))
1129                         break;
1130                 if (!xlog_iclogs_empty(log))
1131                         break;
1132
1133                 needed = 1;
1134                 if (log->l_covered_state == XLOG_STATE_COVER_NEED)
1135                         log->l_covered_state = XLOG_STATE_COVER_DONE;
1136                 else
1137                         log->l_covered_state = XLOG_STATE_COVER_DONE2;
1138                 break;
1139         default:
1140                 needed = 1;
1141                 break;
1142         }
1143         spin_unlock(&log->l_icloglock);
1144         return needed;
1145 }
1146
1147 /*
1148  * We may be holding the log iclog lock upon entering this routine.
1149  */
1150 xfs_lsn_t
1151 xlog_assign_tail_lsn_locked(
1152         struct xfs_mount        *mp)
1153 {
1154         struct xlog             *log = mp->m_log;
1155         struct xfs_log_item     *lip;
1156         xfs_lsn_t               tail_lsn;
1157
1158         assert_spin_locked(&mp->m_ail->ail_lock);
1159
1160         /*
1161          * To make sure we always have a valid LSN for the log tail we keep
1162          * track of the last LSN which was committed in log->l_last_sync_lsn,
1163          * and use that when the AIL was empty.
1164          */
1165         lip = xfs_ail_min(mp->m_ail);
1166         if (lip)
1167                 tail_lsn = lip->li_lsn;
1168         else
1169                 tail_lsn = atomic64_read(&log->l_last_sync_lsn);
1170         trace_xfs_log_assign_tail_lsn(log, tail_lsn);
1171         atomic64_set(&log->l_tail_lsn, tail_lsn);
1172         return tail_lsn;
1173 }
1174
1175 xfs_lsn_t
1176 xlog_assign_tail_lsn(
1177         struct xfs_mount        *mp)
1178 {
1179         xfs_lsn_t               tail_lsn;
1180
1181         spin_lock(&mp->m_ail->ail_lock);
1182         tail_lsn = xlog_assign_tail_lsn_locked(mp);
1183         spin_unlock(&mp->m_ail->ail_lock);
1184
1185         return tail_lsn;
1186 }
1187
1188 /*
1189  * Return the space in the log between the tail and the head.  The head
1190  * is passed in the cycle/bytes formal parms.  In the special case where
1191  * the reserve head has wrapped passed the tail, this calculation is no
1192  * longer valid.  In this case, just return 0 which means there is no space
1193  * in the log.  This works for all places where this function is called
1194  * with the reserve head.  Of course, if the write head were to ever
1195  * wrap the tail, we should blow up.  Rather than catch this case here,
1196  * we depend on other ASSERTions in other parts of the code.   XXXmiken
1197  *
1198  * This code also handles the case where the reservation head is behind
1199  * the tail.  The details of this case are described below, but the end
1200  * result is that we return the size of the log as the amount of space left.
1201  */
1202 STATIC int
1203 xlog_space_left(
1204         struct xlog     *log,
1205         atomic64_t      *head)
1206 {
1207         int             free_bytes;
1208         int             tail_bytes;
1209         int             tail_cycle;
1210         int             head_cycle;
1211         int             head_bytes;
1212
1213         xlog_crack_grant_head(head, &head_cycle, &head_bytes);
1214         xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_bytes);
1215         tail_bytes = BBTOB(tail_bytes);
1216         if (tail_cycle == head_cycle && head_bytes >= tail_bytes)
1217                 free_bytes = log->l_logsize - (head_bytes - tail_bytes);
1218         else if (tail_cycle + 1 < head_cycle)
1219                 return 0;
1220         else if (tail_cycle < head_cycle) {
1221                 ASSERT(tail_cycle == (head_cycle - 1));
1222                 free_bytes = tail_bytes - head_bytes;
1223         } else {
1224                 /*
1225                  * The reservation head is behind the tail.
1226                  * In this case we just want to return the size of the
1227                  * log as the amount of space left.
1228                  */
1229                 xfs_alert(log->l_mp, "xlog_space_left: head behind tail");
1230                 xfs_alert(log->l_mp,
1231                           "  tail_cycle = %d, tail_bytes = %d",
1232                           tail_cycle, tail_bytes);
1233                 xfs_alert(log->l_mp,
1234                           "  GH   cycle = %d, GH   bytes = %d",
1235                           head_cycle, head_bytes);
1236                 ASSERT(0);
1237                 free_bytes = log->l_logsize;
1238         }
1239         return free_bytes;
1240 }
1241
1242
1243 /*
1244  * Log function which is called when an io completes.
1245  *
1246  * The log manager needs its own routine, in order to control what
1247  * happens with the buffer after the write completes.
1248  */
1249 static void
1250 xlog_iodone(xfs_buf_t *bp)
1251 {
1252         struct xlog_in_core     *iclog = bp->b_log_item;
1253         struct xlog             *l = iclog->ic_log;
1254         int                     aborted = 0;
1255
1256 #ifdef DEBUG
1257         /* treat writes with injected CRC errors as failed */
1258         if (iclog->ic_fail_crc)
1259                 bp->b_error = -EIO;
1260 #endif
1261
1262         /*
1263          * Race to shutdown the filesystem if we see an error.
1264          */
1265         if (XFS_TEST_ERROR(bp->b_error, l->l_mp, XFS_ERRTAG_IODONE_IOERR)) {
1266                 xfs_buf_ioerror_alert(bp, __func__);
1267                 xfs_buf_stale(bp);
1268                 xfs_force_shutdown(l->l_mp, SHUTDOWN_LOG_IO_ERROR);
1269                 /*
1270                  * This flag will be propagated to the trans-committed
1271                  * callback routines to let them know that the log-commit
1272                  * didn't succeed.
1273                  */
1274                 aborted = XFS_LI_ABORTED;
1275         } else if (iclog->ic_state & XLOG_STATE_IOERROR) {
1276                 aborted = XFS_LI_ABORTED;
1277         }
1278
1279         /* log I/O is always issued ASYNC */
1280         ASSERT(bp->b_flags & XBF_ASYNC);
1281         xlog_state_done_syncing(iclog, aborted);
1282
1283         /*
1284          * drop the buffer lock now that we are done. Nothing references
1285          * the buffer after this, so an unmount waiting on this lock can now
1286          * tear it down safely. As such, it is unsafe to reference the buffer
1287          * (bp) after the unlock as we could race with it being freed.
1288          */
1289         xfs_buf_unlock(bp);
1290 }
1291
1292 /*
1293  * Return size of each in-core log record buffer.
1294  *
1295  * All machines get 8 x 32kB buffers by default, unless tuned otherwise.
1296  *
1297  * If the filesystem blocksize is too large, we may need to choose a
1298  * larger size since the directory code currently logs entire blocks.
1299  */
1300 STATIC void
1301 xlog_get_iclog_buffer_size(
1302         struct xfs_mount        *mp,
1303         struct xlog             *log)
1304 {
1305         if (mp->m_logbufs <= 0)
1306                 mp->m_logbufs = XLOG_MAX_ICLOGS;
1307         if (mp->m_logbsize <= 0)
1308                 mp->m_logbsize = XLOG_BIG_RECORD_BSIZE;
1309
1310         log->l_iclog_bufs = mp->m_logbufs;
1311         log->l_iclog_size = mp->m_logbsize;
1312
1313         /*
1314          * # headers = size / 32k - one header holds cycles from 32k of data.
1315          */
1316         log->l_iclog_heads =
1317                 DIV_ROUND_UP(mp->m_logbsize, XLOG_HEADER_CYCLE_SIZE);
1318         log->l_iclog_hsize = log->l_iclog_heads << BBSHIFT;
1319 }
1320
1321 void
1322 xfs_log_work_queue(
1323         struct xfs_mount        *mp)
1324 {
1325         queue_delayed_work(mp->m_sync_workqueue, &mp->m_log->l_work,
1326                                 msecs_to_jiffies(xfs_syncd_centisecs * 10));
1327 }
1328
1329 /*
1330  * Every sync period we need to unpin all items in the AIL and push them to
1331  * disk. If there is nothing dirty, then we might need to cover the log to
1332  * indicate that the filesystem is idle.
1333  */
1334 static void
1335 xfs_log_worker(
1336         struct work_struct      *work)
1337 {
1338         struct xlog             *log = container_of(to_delayed_work(work),
1339                                                 struct xlog, l_work);
1340         struct xfs_mount        *mp = log->l_mp;
1341
1342         /* dgc: errors ignored - not fatal and nowhere to report them */
1343         if (xfs_log_need_covered(mp)) {
1344                 /*
1345                  * Dump a transaction into the log that contains no real change.
1346                  * This is needed to stamp the current tail LSN into the log
1347                  * during the covering operation.
1348                  *
1349                  * We cannot use an inode here for this - that will push dirty
1350                  * state back up into the VFS and then periodic inode flushing
1351                  * will prevent log covering from making progress. Hence we
1352                  * synchronously log the superblock instead to ensure the
1353                  * superblock is immediately unpinned and can be written back.
1354                  */
1355                 xfs_sync_sb(mp, true);
1356         } else
1357                 xfs_log_force(mp, 0);
1358
1359         /* start pushing all the metadata that is currently dirty */
1360         xfs_ail_push_all(mp->m_ail);
1361
1362         /* queue us up again */
1363         xfs_log_work_queue(mp);
1364 }
1365
1366 /*
1367  * This routine initializes some of the log structure for a given mount point.
1368  * Its primary purpose is to fill in enough, so recovery can occur.  However,
1369  * some other stuff may be filled in too.
1370  */
1371 STATIC struct xlog *
1372 xlog_alloc_log(
1373         struct xfs_mount        *mp,
1374         struct xfs_buftarg      *log_target,
1375         xfs_daddr_t             blk_offset,
1376         int                     num_bblks)
1377 {
1378         struct xlog             *log;
1379         xlog_rec_header_t       *head;
1380         xlog_in_core_t          **iclogp;
1381         xlog_in_core_t          *iclog, *prev_iclog=NULL;
1382         xfs_buf_t               *bp;
1383         int                     i;
1384         int                     error = -ENOMEM;
1385         uint                    log2_size = 0;
1386
1387         log = kmem_zalloc(sizeof(struct xlog), KM_MAYFAIL);
1388         if (!log) {
1389                 xfs_warn(mp, "Log allocation failed: No memory!");
1390                 goto out;
1391         }
1392
1393         log->l_mp          = mp;
1394         log->l_targ        = log_target;
1395         log->l_logsize     = BBTOB(num_bblks);
1396         log->l_logBBstart  = blk_offset;
1397         log->l_logBBsize   = num_bblks;
1398         log->l_covered_state = XLOG_STATE_COVER_IDLE;
1399         log->l_flags       |= XLOG_ACTIVE_RECOVERY;
1400         INIT_DELAYED_WORK(&log->l_work, xfs_log_worker);
1401
1402         log->l_prev_block  = -1;
1403         /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
1404         xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0);
1405         xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
1406         log->l_curr_cycle  = 1;     /* 0 is bad since this is initial value */
1407
1408         xlog_grant_head_init(&log->l_reserve_head);
1409         xlog_grant_head_init(&log->l_write_head);
1410
1411         error = -EFSCORRUPTED;
1412         if (xfs_sb_version_hassector(&mp->m_sb)) {
1413                 log2_size = mp->m_sb.sb_logsectlog;
1414                 if (log2_size < BBSHIFT) {
1415                         xfs_warn(mp, "Log sector size too small (0x%x < 0x%x)",
1416                                 log2_size, BBSHIFT);
1417                         goto out_free_log;
1418                 }
1419
1420                 log2_size -= BBSHIFT;
1421                 if (log2_size > mp->m_sectbb_log) {
1422                         xfs_warn(mp, "Log sector size too large (0x%x > 0x%x)",
1423                                 log2_size, mp->m_sectbb_log);
1424                         goto out_free_log;
1425                 }
1426
1427                 /* for larger sector sizes, must have v2 or external log */
1428                 if (log2_size && log->l_logBBstart > 0 &&
1429                             !xfs_sb_version_haslogv2(&mp->m_sb)) {
1430                         xfs_warn(mp,
1431                 "log sector size (0x%x) invalid for configuration.",
1432                                 log2_size);
1433                         goto out_free_log;
1434                 }
1435         }
1436         log->l_sectBBsize = 1 << log2_size;
1437
1438         xlog_get_iclog_buffer_size(mp, log);
1439
1440         /*
1441          * Use a NULL block for the extra log buffer used during splits so that
1442          * it will trigger errors if we ever try to do IO on it without first
1443          * having set it up properly.
1444          */
1445         error = -ENOMEM;
1446         bp = xfs_buf_alloc(mp->m_logdev_targp, XFS_BUF_DADDR_NULL,
1447                            BTOBB(log->l_iclog_size), XBF_NO_IOACCT);
1448         if (!bp)
1449                 goto out_free_log;
1450
1451         /*
1452          * The iclogbuf buffer locks are held over IO but we are not going to do
1453          * IO yet.  Hence unlock the buffer so that the log IO path can grab it
1454          * when appropriately.
1455          */
1456         ASSERT(xfs_buf_islocked(bp));
1457         xfs_buf_unlock(bp);
1458
1459         /* use high priority wq for log I/O completion */
1460         bp->b_ioend_wq = mp->m_log_workqueue;
1461         bp->b_iodone = xlog_iodone;
1462         log->l_xbuf = bp;
1463
1464         spin_lock_init(&log->l_icloglock);
1465         init_waitqueue_head(&log->l_flush_wait);
1466
1467         iclogp = &log->l_iclog;
1468         /*
1469          * The amount of memory to allocate for the iclog structure is
1470          * rather funky due to the way the structure is defined.  It is
1471          * done this way so that we can use different sizes for machines
1472          * with different amounts of memory.  See the definition of
1473          * xlog_in_core_t in xfs_log_priv.h for details.
1474          */
1475         ASSERT(log->l_iclog_size >= 4096);
1476         for (i=0; i < log->l_iclog_bufs; i++) {
1477                 *iclogp = kmem_zalloc(sizeof(xlog_in_core_t), KM_MAYFAIL);
1478                 if (!*iclogp)
1479                         goto out_free_iclog;
1480
1481                 iclog = *iclogp;
1482                 iclog->ic_prev = prev_iclog;
1483                 prev_iclog = iclog;
1484
1485                 bp = xfs_buf_get_uncached(mp->m_logdev_targp,
1486                                           BTOBB(log->l_iclog_size),
1487                                           XBF_NO_IOACCT);
1488                 if (!bp)
1489                         goto out_free_iclog;
1490
1491                 ASSERT(xfs_buf_islocked(bp));
1492                 xfs_buf_unlock(bp);
1493
1494                 /* use high priority wq for log I/O completion */
1495                 bp->b_ioend_wq = mp->m_log_workqueue;
1496                 bp->b_iodone = xlog_iodone;
1497                 iclog->ic_bp = bp;
1498                 iclog->ic_data = bp->b_addr;
1499 #ifdef DEBUG
1500                 log->l_iclog_bak[i] = &iclog->ic_header;
1501 #endif
1502                 head = &iclog->ic_header;
1503                 memset(head, 0, sizeof(xlog_rec_header_t));
1504                 head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1505                 head->h_version = cpu_to_be32(
1506                         xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? 2 : 1);
1507                 head->h_size = cpu_to_be32(log->l_iclog_size);
1508                 /* new fields */
1509                 head->h_fmt = cpu_to_be32(XLOG_FMT);
1510                 memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));
1511
1512                 iclog->ic_size = BBTOB(bp->b_length) - log->l_iclog_hsize;
1513                 iclog->ic_state = XLOG_STATE_ACTIVE;
1514                 iclog->ic_log = log;
1515                 atomic_set(&iclog->ic_refcnt, 0);
1516                 spin_lock_init(&iclog->ic_callback_lock);
1517                 iclog->ic_callback_tail = &(iclog->ic_callback);
1518                 iclog->ic_datap = (char *)iclog->ic_data + log->l_iclog_hsize;
1519
1520                 init_waitqueue_head(&iclog->ic_force_wait);
1521                 init_waitqueue_head(&iclog->ic_write_wait);
1522
1523                 iclogp = &iclog->ic_next;
1524         }
1525         *iclogp = log->l_iclog;                 /* complete ring */
1526         log->l_iclog->ic_prev = prev_iclog;     /* re-write 1st prev ptr */
1527
1528         error = xlog_cil_init(log);
1529         if (error)
1530                 goto out_free_iclog;
1531         return log;
1532
1533 out_free_iclog:
1534         for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
1535                 prev_iclog = iclog->ic_next;
1536                 if (iclog->ic_bp)
1537                         xfs_buf_free(iclog->ic_bp);
1538                 kmem_free(iclog);
1539         }
1540         xfs_buf_free(log->l_xbuf);
1541 out_free_log:
1542         kmem_free(log);
1543 out:
1544         return ERR_PTR(error);
1545 }       /* xlog_alloc_log */
1546
1547
1548 /*
1549  * Write out the commit record of a transaction associated with the given
1550  * ticket.  Return the lsn of the commit record.
1551  */
1552 STATIC int
1553 xlog_commit_record(
1554         struct xlog             *log,
1555         struct xlog_ticket      *ticket,
1556         struct xlog_in_core     **iclog,
1557         xfs_lsn_t               *commitlsnp)
1558 {
1559         struct xfs_mount *mp = log->l_mp;
1560         int     error;
1561         struct xfs_log_iovec reg = {
1562                 .i_addr = NULL,
1563                 .i_len = 0,
1564                 .i_type = XLOG_REG_TYPE_COMMIT,
1565         };
1566         struct xfs_log_vec vec = {
1567                 .lv_niovecs = 1,
1568                 .lv_iovecp = &reg,
1569         };
1570
1571         ASSERT_ALWAYS(iclog);
1572         error = xlog_write(log, &vec, ticket, commitlsnp, iclog,
1573                                         XLOG_COMMIT_TRANS);
1574         if (error)
1575                 xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
1576         return error;
1577 }
1578
1579 /*
1580  * Push on the buffer cache code if we ever use more than 75% of the on-disk
1581  * log space.  This code pushes on the lsn which would supposedly free up
1582  * the 25% which we want to leave free.  We may need to adopt a policy which
1583  * pushes on an lsn which is further along in the log once we reach the high
1584  * water mark.  In this manner, we would be creating a low water mark.
1585  */
1586 STATIC void
1587 xlog_grant_push_ail(
1588         struct xlog     *log,
1589         int             need_bytes)
1590 {
1591         xfs_lsn_t       threshold_lsn = 0;
1592         xfs_lsn_t       last_sync_lsn;
1593         int             free_blocks;
1594         int             free_bytes;
1595         int             threshold_block;
1596         int             threshold_cycle;
1597         int             free_threshold;
1598
1599         ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
1600
1601         free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1602         free_blocks = BTOBBT(free_bytes);
1603
1604         /*
1605          * Set the threshold for the minimum number of free blocks in the
1606          * log to the maximum of what the caller needs, one quarter of the
1607          * log, and 256 blocks.
1608          */
1609         free_threshold = BTOBB(need_bytes);
1610         free_threshold = max(free_threshold, (log->l_logBBsize >> 2));
1611         free_threshold = max(free_threshold, 256);
1612         if (free_blocks >= free_threshold)
1613                 return;
1614
1615         xlog_crack_atomic_lsn(&log->l_tail_lsn, &threshold_cycle,
1616                                                 &threshold_block);
1617         threshold_block += free_threshold;
1618         if (threshold_block >= log->l_logBBsize) {
1619                 threshold_block -= log->l_logBBsize;
1620                 threshold_cycle += 1;
1621         }
1622         threshold_lsn = xlog_assign_lsn(threshold_cycle,
1623                                         threshold_block);
1624         /*
1625          * Don't pass in an lsn greater than the lsn of the last
1626          * log record known to be on disk. Use a snapshot of the last sync lsn
1627          * so that it doesn't change between the compare and the set.
1628          */
1629         last_sync_lsn = atomic64_read(&log->l_last_sync_lsn);
1630         if (XFS_LSN_CMP(threshold_lsn, last_sync_lsn) > 0)
1631                 threshold_lsn = last_sync_lsn;
1632
1633         /*
1634          * Get the transaction layer to kick the dirty buffers out to
1635          * disk asynchronously. No point in trying to do this if
1636          * the filesystem is shutting down.
1637          */
1638         if (!XLOG_FORCED_SHUTDOWN(log))
1639                 xfs_ail_push(log->l_ailp, threshold_lsn);
1640 }
1641
1642 /*
1643  * Stamp cycle number in every block
1644  */
1645 STATIC void
1646 xlog_pack_data(
1647         struct xlog             *log,
1648         struct xlog_in_core     *iclog,
1649         int                     roundoff)
1650 {
1651         int                     i, j, k;
1652         int                     size = iclog->ic_offset + roundoff;
1653         __be32                  cycle_lsn;
1654         char                    *dp;
1655
1656         cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn);
1657
1658         dp = iclog->ic_datap;
1659         for (i = 0; i < BTOBB(size); i++) {
1660                 if (i >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE))
1661                         break;
1662                 iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp;
1663                 *(__be32 *)dp = cycle_lsn;
1664                 dp += BBSIZE;
1665         }
1666
1667         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1668                 xlog_in_core_2_t *xhdr = iclog->ic_data;
1669
1670                 for ( ; i < BTOBB(size); i++) {
1671                         j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1672                         k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1673                         xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp;
1674                         *(__be32 *)dp = cycle_lsn;
1675                         dp += BBSIZE;
1676                 }
1677
1678                 for (i = 1; i < log->l_iclog_heads; i++)
1679                         xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
1680         }
1681 }
1682
1683 /*
1684  * Calculate the checksum for a log buffer.
1685  *
1686  * This is a little more complicated than it should be because the various
1687  * headers and the actual data are non-contiguous.
1688  */
1689 __le32
1690 xlog_cksum(
1691         struct xlog             *log,
1692         struct xlog_rec_header  *rhead,
1693         char                    *dp,
1694         int                     size)
1695 {
1696         uint32_t                crc;
1697
1698         /* first generate the crc for the record header ... */
1699         crc = xfs_start_cksum_update((char *)rhead,
1700                               sizeof(struct xlog_rec_header),
1701                               offsetof(struct xlog_rec_header, h_crc));
1702
1703         /* ... then for additional cycle data for v2 logs ... */
1704         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1705                 union xlog_in_core2 *xhdr = (union xlog_in_core2 *)rhead;
1706                 int             i;
1707                 int             xheads;
1708
1709                 xheads = size / XLOG_HEADER_CYCLE_SIZE;
1710                 if (size % XLOG_HEADER_CYCLE_SIZE)
1711                         xheads++;
1712
1713                 for (i = 1; i < xheads; i++) {
1714                         crc = crc32c(crc, &xhdr[i].hic_xheader,
1715                                      sizeof(struct xlog_rec_ext_header));
1716                 }
1717         }
1718
1719         /* ... and finally for the payload */
1720         crc = crc32c(crc, dp, size);
1721
1722         return xfs_end_cksum(crc);
1723 }
1724
1725 STATIC void
1726 xlog_write_iclog(
1727         struct xlog             *log,
1728         struct xlog_in_core     *iclog,
1729         struct xfs_buf          *bp,
1730         uint64_t                bno,
1731         bool                    need_flush)
1732 {
1733         ASSERT(bno < log->l_logBBsize);
1734         ASSERT(bno + bp->b_io_length <= log->l_logBBsize);
1735
1736         bp->b_maps[0].bm_bn = log->l_logBBstart + bno;
1737         bp->b_log_item = iclog;
1738         bp->b_flags &= ~XBF_FLUSH;
1739         bp->b_flags |= (XBF_ASYNC | XBF_SYNCIO | XBF_WRITE | XBF_FUA);
1740         if (need_flush)
1741                 bp->b_flags |= XBF_FLUSH;
1742
1743         /*
1744          * We lock the iclogbufs here so that we can serialise against I/O
1745          * completion during unmount.  We might be processing a shutdown
1746          * triggered during unmount, and that can occur asynchronously to the
1747          * unmount thread, and hence we need to ensure that completes before
1748          * tearing down the iclogbufs.  Hence we need to hold the buffer lock
1749          * across the log IO to archieve that.
1750          */
1751         xfs_buf_lock(bp);
1752         if (unlikely(iclog->ic_state & XLOG_STATE_IOERROR)) {
1753                 xfs_buf_ioerror(bp, -EIO);
1754                 xfs_buf_stale(bp);
1755                 xfs_buf_ioend(bp);
1756                 /*
1757                  * It would seem logical to return EIO here, but we rely on
1758                  * the log state machine to propagate I/O errors instead of
1759                  * doing it here. Similarly, IO completion will unlock the
1760                  * buffer, so we don't do it here.
1761                  */
1762                 return;
1763         }
1764
1765         xfs_buf_submit(bp);
1766 }
1767
1768 /*
1769  * We need to bump cycle number for the part of the iclog that is
1770  * written to the start of the log. Watch out for the header magic
1771  * number case, though.
1772  */
1773 static unsigned int
1774 xlog_split_iclog(
1775         struct xlog             *log,
1776         void                    *data,
1777         uint64_t                bno,
1778         unsigned int            count)
1779 {
1780         unsigned int            split_offset = BBTOB(log->l_logBBsize - bno);
1781         unsigned int            i;
1782
1783         for (i = split_offset; i < count; i += BBSIZE) {
1784                 uint32_t cycle = get_unaligned_be32(data + i);
1785
1786                 if (++cycle == XLOG_HEADER_MAGIC_NUM)
1787                         cycle++;
1788                 put_unaligned_be32(cycle, data + i);
1789         }
1790
1791         return split_offset;
1792 }
1793
1794 static int
1795 xlog_calc_iclog_size(
1796         struct xlog             *log,
1797         struct xlog_in_core     *iclog,
1798         uint32_t                *roundoff)
1799 {
1800         uint32_t                count_init, count;
1801         bool                    use_lsunit;
1802
1803         use_lsunit = xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
1804                         log->l_mp->m_sb.sb_logsunit > 1;
1805
1806         /* Add for LR header */
1807         count_init = log->l_iclog_hsize + iclog->ic_offset;
1808
1809         /* Round out the log write size */
1810         if (use_lsunit) {
1811                 /* we have a v2 stripe unit to use */
1812                 count = XLOG_LSUNITTOB(log, XLOG_BTOLSUNIT(log, count_init));
1813         } else {
1814                 count = BBTOB(BTOBB(count_init));
1815         }
1816
1817         ASSERT(count >= count_init);
1818         *roundoff = count - count_init;
1819
1820         if (use_lsunit)
1821                 ASSERT(*roundoff < log->l_mp->m_sb.sb_logsunit);
1822         else
1823                 ASSERT(*roundoff < BBTOB(1));
1824         return count;
1825 }
1826
1827 /*
1828  * Flush out the in-core log (iclog) to the on-disk log in an asynchronous
1829  * fashion.  Previously, we should have moved the current iclog
1830  * ptr in the log to point to the next available iclog.  This allows further
1831  * write to continue while this code syncs out an iclog ready to go.
1832  * Before an in-core log can be written out, the data section must be scanned
1833  * to save away the 1st word of each BBSIZE block into the header.  We replace
1834  * it with the current cycle count.  Each BBSIZE block is tagged with the
1835  * cycle count because there in an implicit assumption that drives will
1836  * guarantee that entire 512 byte blocks get written at once.  In other words,
1837  * we can't have part of a 512 byte block written and part not written.  By
1838  * tagging each block, we will know which blocks are valid when recovering
1839  * after an unclean shutdown.
1840  *
1841  * This routine is single threaded on the iclog.  No other thread can be in
1842  * this routine with the same iclog.  Changing contents of iclog can there-
1843  * fore be done without grabbing the state machine lock.  Updating the global
1844  * log will require grabbing the lock though.
1845  *
1846  * The entire log manager uses a logical block numbering scheme.  Only
1847  * xlog_write_iclog knows about the fact that the log may not start with
1848  * block zero on a given device.
1849  */
1850 STATIC void
1851 xlog_sync(
1852         struct xlog             *log,
1853         struct xlog_in_core     *iclog)
1854 {
1855         unsigned int            count;          /* byte count of bwrite */
1856         unsigned int            roundoff;       /* roundoff to BB or stripe */
1857         uint64_t                bno;
1858         unsigned int            split = 0;
1859         unsigned int            size;
1860         bool                    need_flush = true;
1861
1862         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
1863
1864         count = xlog_calc_iclog_size(log, iclog, &roundoff);
1865
1866         /* move grant heads by roundoff in sync */
1867         xlog_grant_add_space(log, &log->l_reserve_head.grant, roundoff);
1868         xlog_grant_add_space(log, &log->l_write_head.grant, roundoff);
1869
1870         /* put cycle number in every block */
1871         xlog_pack_data(log, iclog, roundoff);
1872
1873         /* real byte length */
1874         size = iclog->ic_offset;
1875         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb))
1876                 size += roundoff;
1877         iclog->ic_header.h_len = cpu_to_be32(size);
1878
1879         XFS_STATS_INC(log->l_mp, xs_log_writes);
1880         XFS_STATS_ADD(log->l_mp, xs_log_blocks, BTOBB(count));
1881
1882         bno = BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn));
1883
1884         /* Do we need to split this write into 2 parts? */
1885         if (bno + BTOBB(count) > log->l_logBBsize)
1886                 split = xlog_split_iclog(log, &iclog->ic_header, bno, count);
1887
1888         /* calculcate the checksum */
1889         iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header,
1890                                             iclog->ic_datap, size);
1891         /*
1892          * Intentionally corrupt the log record CRC based on the error injection
1893          * frequency, if defined. This facilitates testing log recovery in the
1894          * event of torn writes. Hence, set the IOABORT state to abort the log
1895          * write on I/O completion and shutdown the fs. The subsequent mount
1896          * detects the bad CRC and attempts to recover.
1897          */
1898 #ifdef DEBUG
1899         if (XFS_TEST_ERROR(false, log->l_mp, XFS_ERRTAG_LOG_BAD_CRC)) {
1900                 iclog->ic_header.h_crc &= cpu_to_le32(0xAAAAAAAA);
1901                 iclog->ic_fail_crc = true;
1902                 xfs_warn(log->l_mp,
1903         "Intentionally corrupted log record at LSN 0x%llx. Shutdown imminent.",
1904                          be64_to_cpu(iclog->ic_header.h_lsn));
1905         }
1906 #endif
1907
1908         /*
1909          * Flush the data device before flushing the log to make sure all meta
1910          * data written back from the AIL actually made it to disk before
1911          * stamping the new log tail LSN into the log buffer.  For an external
1912          * log we need to issue the flush explicitly, and unfortunately
1913          * synchronously here; for an internal log we can simply use the block
1914          * layer state machine for preflushes.
1915          */
1916         if (log->l_mp->m_logdev_targp != log->l_mp->m_ddev_targp || split) {
1917                 xfs_blkdev_issue_flush(log->l_mp->m_ddev_targp);
1918                 need_flush = false;
1919         }
1920
1921         iclog->ic_bp->b_io_length = BTOBB(split ? split : count);
1922         iclog->ic_bwritecnt = split ? 2 : 1;
1923
1924         xlog_verify_iclog(log, iclog, count, true);
1925         xlog_write_iclog(log, iclog, iclog->ic_bp, bno, need_flush);
1926
1927         if (split) {
1928                 xfs_buf_associate_memory(iclog->ic_log->l_xbuf,
1929                                 (char *)&iclog->ic_header + split,
1930                                 count - split);
1931                 xlog_write_iclog(log, iclog, iclog->ic_log->l_xbuf, 0, false);
1932         }
1933 }
1934
1935 /*
1936  * Deallocate a log structure
1937  */
1938 STATIC void
1939 xlog_dealloc_log(
1940         struct xlog     *log)
1941 {
1942         xlog_in_core_t  *iclog, *next_iclog;
1943         int             i;
1944
1945         xlog_cil_destroy(log);
1946
1947         /*
1948          * Cycle all the iclogbuf locks to make sure all log IO completion
1949          * is done before we tear down these buffers.
1950          */
1951         iclog = log->l_iclog;
1952         for (i = 0; i < log->l_iclog_bufs; i++) {
1953                 xfs_buf_lock(iclog->ic_bp);
1954                 xfs_buf_unlock(iclog->ic_bp);
1955                 iclog = iclog->ic_next;
1956         }
1957
1958         /*
1959          * Always need to ensure that the extra buffer does not point to memory
1960          * owned by another log buffer before we free it. Also, cycle the lock
1961          * first to ensure we've completed IO on it.
1962          */
1963         xfs_buf_lock(log->l_xbuf);
1964         xfs_buf_unlock(log->l_xbuf);
1965         xfs_buf_set_empty(log->l_xbuf, BTOBB(log->l_iclog_size));
1966         xfs_buf_free(log->l_xbuf);
1967
1968         iclog = log->l_iclog;
1969         for (i = 0; i < log->l_iclog_bufs; i++) {
1970                 xfs_buf_free(iclog->ic_bp);
1971                 next_iclog = iclog->ic_next;
1972                 kmem_free(iclog);
1973                 iclog = next_iclog;
1974         }
1975
1976         log->l_mp->m_log = NULL;
1977         kmem_free(log);
1978 }       /* xlog_dealloc_log */
1979
1980 /*
1981  * Update counters atomically now that memcpy is done.
1982  */
1983 /* ARGSUSED */
1984 static inline void
1985 xlog_state_finish_copy(
1986         struct xlog             *log,
1987         struct xlog_in_core     *iclog,
1988         int                     record_cnt,
1989         int                     copy_bytes)
1990 {
1991         spin_lock(&log->l_icloglock);
1992
1993         be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
1994         iclog->ic_offset += copy_bytes;
1995
1996         spin_unlock(&log->l_icloglock);
1997 }       /* xlog_state_finish_copy */
1998
1999
2000
2001
2002 /*
2003  * print out info relating to regions written which consume
2004  * the reservation
2005  */
2006 void
2007 xlog_print_tic_res(
2008         struct xfs_mount        *mp,
2009         struct xlog_ticket      *ticket)
2010 {
2011         uint i;
2012         uint ophdr_spc = ticket->t_res_num_ophdrs * (uint)sizeof(xlog_op_header_t);
2013
2014         /* match with XLOG_REG_TYPE_* in xfs_log.h */
2015 #define REG_TYPE_STR(type, str) [XLOG_REG_TYPE_##type] = str
2016         static char *res_type_str[] = {
2017             REG_TYPE_STR(BFORMAT, "bformat"),
2018             REG_TYPE_STR(BCHUNK, "bchunk"),
2019             REG_TYPE_STR(EFI_FORMAT, "efi_format"),
2020             REG_TYPE_STR(EFD_FORMAT, "efd_format"),
2021             REG_TYPE_STR(IFORMAT, "iformat"),
2022             REG_TYPE_STR(ICORE, "icore"),
2023             REG_TYPE_STR(IEXT, "iext"),
2024             REG_TYPE_STR(IBROOT, "ibroot"),
2025             REG_TYPE_STR(ILOCAL, "ilocal"),
2026             REG_TYPE_STR(IATTR_EXT, "iattr_ext"),
2027             REG_TYPE_STR(IATTR_BROOT, "iattr_broot"),
2028             REG_TYPE_STR(IATTR_LOCAL, "iattr_local"),
2029             REG_TYPE_STR(QFORMAT, "qformat"),
2030             REG_TYPE_STR(DQUOT, "dquot"),
2031             REG_TYPE_STR(QUOTAOFF, "quotaoff"),
2032             REG_TYPE_STR(LRHEADER, "LR header"),
2033             REG_TYPE_STR(UNMOUNT, "unmount"),
2034             REG_TYPE_STR(COMMIT, "commit"),
2035             REG_TYPE_STR(TRANSHDR, "trans header"),
2036             REG_TYPE_STR(ICREATE, "inode create"),
2037             REG_TYPE_STR(RUI_FORMAT, "rui_format"),
2038             REG_TYPE_STR(RUD_FORMAT, "rud_format"),
2039             REG_TYPE_STR(CUI_FORMAT, "cui_format"),
2040             REG_TYPE_STR(CUD_FORMAT, "cud_format"),
2041             REG_TYPE_STR(BUI_FORMAT, "bui_format"),
2042             REG_TYPE_STR(BUD_FORMAT, "bud_format"),
2043         };
2044         BUILD_BUG_ON(ARRAY_SIZE(res_type_str) != XLOG_REG_TYPE_MAX + 1);
2045 #undef REG_TYPE_STR
2046
2047         xfs_warn(mp, "ticket reservation summary:");
2048         xfs_warn(mp, "  unit res    = %d bytes",
2049                  ticket->t_unit_res);
2050         xfs_warn(mp, "  current res = %d bytes",
2051                  ticket->t_curr_res);
2052         xfs_warn(mp, "  total reg   = %u bytes (o/flow = %u bytes)",
2053                  ticket->t_res_arr_sum, ticket->t_res_o_flow);
2054         xfs_warn(mp, "  ophdrs      = %u (ophdr space = %u bytes)",
2055                  ticket->t_res_num_ophdrs, ophdr_spc);
2056         xfs_warn(mp, "  ophdr + reg = %u bytes",
2057                  ticket->t_res_arr_sum + ticket->t_res_o_flow + ophdr_spc);
2058         xfs_warn(mp, "  num regions = %u",
2059                  ticket->t_res_num);
2060
2061         for (i = 0; i < ticket->t_res_num; i++) {
2062                 uint r_type = ticket->t_res_arr[i].r_type;
2063                 xfs_warn(mp, "region[%u]: %s - %u bytes", i,
2064                             ((r_type <= 0 || r_type > XLOG_REG_TYPE_MAX) ?
2065                             "bad-rtype" : res_type_str[r_type]),
2066                             ticket->t_res_arr[i].r_len);
2067         }
2068 }
2069
2070 /*
2071  * Print a summary of the transaction.
2072  */
2073 void
2074 xlog_print_trans(
2075         struct xfs_trans        *tp)
2076 {
2077         struct xfs_mount        *mp = tp->t_mountp;
2078         struct xfs_log_item     *lip;
2079
2080         /* dump core transaction and ticket info */
2081         xfs_warn(mp, "transaction summary:");
2082         xfs_warn(mp, "  log res   = %d", tp->t_log_res);
2083         xfs_warn(mp, "  log count = %d", tp->t_log_count);
2084         xfs_warn(mp, "  flags     = 0x%x", tp->t_flags);
2085
2086         xlog_print_tic_res(mp, tp->t_ticket);
2087
2088         /* dump each log item */
2089         list_for_each_entry(lip, &tp->t_items, li_trans) {
2090                 struct xfs_log_vec      *lv = lip->li_lv;
2091                 struct xfs_log_iovec    *vec;
2092                 int                     i;
2093
2094                 xfs_warn(mp, "log item: ");
2095                 xfs_warn(mp, "  type    = 0x%x", lip->li_type);
2096                 xfs_warn(mp, "  flags   = 0x%lx", lip->li_flags);
2097                 if (!lv)
2098                         continue;
2099                 xfs_warn(mp, "  niovecs = %d", lv->lv_niovecs);
2100                 xfs_warn(mp, "  size    = %d", lv->lv_size);
2101                 xfs_warn(mp, "  bytes   = %d", lv->lv_bytes);
2102                 xfs_warn(mp, "  buf len = %d", lv->lv_buf_len);
2103
2104                 /* dump each iovec for the log item */
2105                 vec = lv->lv_iovecp;
2106                 for (i = 0; i < lv->lv_niovecs; i++) {
2107                         int dumplen = min(vec->i_len, 32);
2108
2109                         xfs_warn(mp, "  iovec[%d]", i);
2110                         xfs_warn(mp, "    type  = 0x%x", vec->i_type);
2111                         xfs_warn(mp, "    len   = %d", vec->i_len);
2112                         xfs_warn(mp, "    first %d bytes of iovec[%d]:", dumplen, i);
2113                         xfs_hex_dump(vec->i_addr, dumplen);
2114
2115                         vec++;
2116                 }
2117         }
2118 }
2119
2120 /*
2121  * Calculate the potential space needed by the log vector.  Each region gets
2122  * its own xlog_op_header_t and may need to be double word aligned.
2123  */
2124 static int
2125 xlog_write_calc_vec_length(
2126         struct xlog_ticket      *ticket,
2127         struct xfs_log_vec      *log_vector)
2128 {
2129         struct xfs_log_vec      *lv;
2130         int                     headers = 0;
2131         int                     len = 0;
2132         int                     i;
2133
2134         /* acct for start rec of xact */
2135         if (ticket->t_flags & XLOG_TIC_INITED)
2136                 headers++;
2137
2138         for (lv = log_vector; lv; lv = lv->lv_next) {
2139                 /* we don't write ordered log vectors */
2140                 if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED)
2141                         continue;
2142
2143                 headers += lv->lv_niovecs;
2144
2145                 for (i = 0; i < lv->lv_niovecs; i++) {
2146                         struct xfs_log_iovec    *vecp = &lv->lv_iovecp[i];
2147
2148                         len += vecp->i_len;
2149                         xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type);
2150                 }
2151         }
2152
2153         ticket->t_res_num_ophdrs += headers;
2154         len += headers * sizeof(struct xlog_op_header);
2155
2156         return len;
2157 }
2158
2159 /*
2160  * If first write for transaction, insert start record  We can't be trying to
2161  * commit if we are inited.  We can't have any "partial_copy" if we are inited.
2162  */
2163 static int
2164 xlog_write_start_rec(
2165         struct xlog_op_header   *ophdr,
2166         struct xlog_ticket      *ticket)
2167 {
2168         if (!(ticket->t_flags & XLOG_TIC_INITED))
2169                 return 0;
2170
2171         ophdr->oh_tid   = cpu_to_be32(ticket->t_tid);
2172         ophdr->oh_clientid = ticket->t_clientid;
2173         ophdr->oh_len = 0;
2174         ophdr->oh_flags = XLOG_START_TRANS;
2175         ophdr->oh_res2 = 0;
2176
2177         ticket->t_flags &= ~XLOG_TIC_INITED;
2178
2179         return sizeof(struct xlog_op_header);
2180 }
2181
2182 static xlog_op_header_t *
2183 xlog_write_setup_ophdr(
2184         struct xlog             *log,
2185         struct xlog_op_header   *ophdr,
2186         struct xlog_ticket      *ticket,
2187         uint                    flags)
2188 {
2189         ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2190         ophdr->oh_clientid = ticket->t_clientid;
2191         ophdr->oh_res2 = 0;
2192
2193         /* are we copying a commit or unmount record? */
2194         ophdr->oh_flags = flags;
2195
2196         /*
2197          * We've seen logs corrupted with bad transaction client ids.  This
2198          * makes sure that XFS doesn't generate them on.  Turn this into an EIO
2199          * and shut down the filesystem.
2200          */
2201         switch (ophdr->oh_clientid)  {
2202         case XFS_TRANSACTION:
2203         case XFS_VOLUME:
2204         case XFS_LOG:
2205                 break;
2206         default:
2207                 xfs_warn(log->l_mp,
2208                         "Bad XFS transaction clientid 0x%x in ticket "PTR_FMT,
2209                         ophdr->oh_clientid, ticket);
2210                 return NULL;
2211         }
2212
2213         return ophdr;
2214 }
2215
2216 /*
2217  * Set up the parameters of the region copy into the log. This has
2218  * to handle region write split across multiple log buffers - this
2219  * state is kept external to this function so that this code can
2220  * be written in an obvious, self documenting manner.
2221  */
2222 static int
2223 xlog_write_setup_copy(
2224         struct xlog_ticket      *ticket,
2225         struct xlog_op_header   *ophdr,
2226         int                     space_available,
2227         int                     space_required,
2228         int                     *copy_off,
2229         int                     *copy_len,
2230         int                     *last_was_partial_copy,
2231         int                     *bytes_consumed)
2232 {
2233         int                     still_to_copy;
2234
2235         still_to_copy = space_required - *bytes_consumed;
2236         *copy_off = *bytes_consumed;
2237
2238         if (still_to_copy <= space_available) {
2239                 /* write of region completes here */
2240                 *copy_len = still_to_copy;
2241                 ophdr->oh_len = cpu_to_be32(*copy_len);
2242                 if (*last_was_partial_copy)
2243                         ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
2244                 *last_was_partial_copy = 0;
2245                 *bytes_consumed = 0;
2246                 return 0;
2247         }
2248
2249         /* partial write of region, needs extra log op header reservation */
2250         *copy_len = space_available;
2251         ophdr->oh_len = cpu_to_be32(*copy_len);
2252         ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
2253         if (*last_was_partial_copy)
2254                 ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
2255         *bytes_consumed += *copy_len;
2256         (*last_was_partial_copy)++;
2257
2258         /* account for new log op header */
2259         ticket->t_curr_res -= sizeof(struct xlog_op_header);
2260         ticket->t_res_num_ophdrs++;
2261
2262         return sizeof(struct xlog_op_header);
2263 }
2264
2265 static int
2266 xlog_write_copy_finish(
2267         struct xlog             *log,
2268         struct xlog_in_core     *iclog,
2269         uint                    flags,
2270         int                     *record_cnt,
2271         int                     *data_cnt,
2272         int                     *partial_copy,
2273         int                     *partial_copy_len,
2274         int                     log_offset,
2275         struct xlog_in_core     **commit_iclog)
2276 {
2277         if (*partial_copy) {
2278                 /*
2279                  * This iclog has already been marked WANT_SYNC by
2280                  * xlog_state_get_iclog_space.
2281                  */
2282                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2283                 *record_cnt = 0;
2284                 *data_cnt = 0;
2285                 return xlog_state_release_iclog(log, iclog);
2286         }
2287
2288         *partial_copy = 0;
2289         *partial_copy_len = 0;
2290
2291         if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
2292                 /* no more space in this iclog - push it. */
2293                 xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2294                 *record_cnt = 0;
2295                 *data_cnt = 0;
2296
2297                 spin_lock(&log->l_icloglock);
2298                 xlog_state_want_sync(log, iclog);
2299                 spin_unlock(&log->l_icloglock);
2300
2301                 if (!commit_iclog)
2302                         return xlog_state_release_iclog(log, iclog);
2303                 ASSERT(flags & XLOG_COMMIT_TRANS);
2304                 *commit_iclog = iclog;
2305         }
2306
2307         return 0;
2308 }
2309
2310 /*
2311  * Write some region out to in-core log
2312  *
2313  * This will be called when writing externally provided regions or when
2314  * writing out a commit record for a given transaction.
2315  *
2316  * General algorithm:
2317  *      1. Find total length of this write.  This may include adding to the
2318  *              lengths passed in.
2319  *      2. Check whether we violate the tickets reservation.
2320  *      3. While writing to this iclog
2321  *          A. Reserve as much space in this iclog as can get
2322  *          B. If this is first write, save away start lsn
2323  *          C. While writing this region:
2324  *              1. If first write of transaction, write start record
2325  *              2. Write log operation header (header per region)
2326  *              3. Find out if we can fit entire region into this iclog
2327  *              4. Potentially, verify destination memcpy ptr
2328  *              5. Memcpy (partial) region
2329  *              6. If partial copy, release iclog; otherwise, continue
2330  *                      copying more regions into current iclog
2331  *      4. Mark want sync bit (in simulation mode)
2332  *      5. Release iclog for potential flush to on-disk log.
2333  *
2334  * ERRORS:
2335  * 1.   Panic if reservation is overrun.  This should never happen since
2336  *      reservation amounts are generated internal to the filesystem.
2337  * NOTES:
2338  * 1. Tickets are single threaded data structures.
2339  * 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
2340  *      syncing routine.  When a single log_write region needs to span
2341  *      multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
2342  *      on all log operation writes which don't contain the end of the
2343  *      region.  The XLOG_END_TRANS bit is used for the in-core log
2344  *      operation which contains the end of the continued log_write region.
2345  * 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
2346  *      we don't really know exactly how much space will be used.  As a result,
2347  *      we don't update ic_offset until the end when we know exactly how many
2348  *      bytes have been written out.
2349  */
2350 int
2351 xlog_write(
2352         struct xlog             *log,
2353         struct xfs_log_vec      *log_vector,
2354         struct xlog_ticket      *ticket,
2355         xfs_lsn_t               *start_lsn,
2356         struct xlog_in_core     **commit_iclog,
2357         uint                    flags)
2358 {
2359         struct xlog_in_core     *iclog = NULL;
2360         struct xfs_log_iovec    *vecp;
2361         struct xfs_log_vec      *lv;
2362         int                     len;
2363         int                     index;
2364         int                     partial_copy = 0;
2365         int                     partial_copy_len = 0;
2366         int                     contwr = 0;
2367         int                     record_cnt = 0;
2368         int                     data_cnt = 0;
2369         int                     error;
2370
2371         *start_lsn = 0;
2372
2373         len = xlog_write_calc_vec_length(ticket, log_vector);
2374
2375         /*
2376          * Region headers and bytes are already accounted for.
2377          * We only need to take into account start records and
2378          * split regions in this function.
2379          */
2380         if (ticket->t_flags & XLOG_TIC_INITED)
2381                 ticket->t_curr_res -= sizeof(xlog_op_header_t);
2382
2383         /*
2384          * Commit record headers need to be accounted for. These
2385          * come in as separate writes so are easy to detect.
2386          */
2387         if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS))
2388                 ticket->t_curr_res -= sizeof(xlog_op_header_t);
2389
2390         if (ticket->t_curr_res < 0) {
2391                 xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
2392                      "ctx ticket reservation ran out. Need to up reservation");
2393                 xlog_print_tic_res(log->l_mp, ticket);
2394                 xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
2395         }
2396
2397         index = 0;
2398         lv = log_vector;
2399         vecp = lv->lv_iovecp;
2400         while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2401                 void            *ptr;
2402                 int             log_offset;
2403
2404                 error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
2405                                                    &contwr, &log_offset);
2406                 if (error)
2407                         return error;
2408
2409                 ASSERT(log_offset <= iclog->ic_size - 1);
2410                 ptr = iclog->ic_datap + log_offset;
2411
2412                 /* start_lsn is the first lsn written to. That's all we need. */
2413                 if (!*start_lsn)
2414                         *start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2415
2416                 /*
2417                  * This loop writes out as many regions as can fit in the amount
2418                  * of space which was allocated by xlog_state_get_iclog_space().
2419                  */
2420                 while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
2421                         struct xfs_log_iovec    *reg;
2422                         struct xlog_op_header   *ophdr;
2423                         int                     start_rec_copy;
2424                         int                     copy_len;
2425                         int                     copy_off;
2426                         bool                    ordered = false;
2427
2428                         /* ordered log vectors have no regions to write */
2429                         if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) {
2430                                 ASSERT(lv->lv_niovecs == 0);
2431                                 ordered = true;
2432                                 goto next_lv;
2433                         }
2434
2435                         reg = &vecp[index];
2436                         ASSERT(reg->i_len % sizeof(int32_t) == 0);
2437                         ASSERT((unsigned long)ptr % sizeof(int32_t) == 0);
2438
2439                         start_rec_copy = xlog_write_start_rec(ptr, ticket);
2440                         if (start_rec_copy) {
2441                                 record_cnt++;
2442                                 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2443                                                    start_rec_copy);
2444                         }
2445
2446                         ophdr = xlog_write_setup_ophdr(log, ptr, ticket, flags);
2447                         if (!ophdr)
2448                                 return -EIO;
2449
2450                         xlog_write_adv_cnt(&ptr, &len, &log_offset,
2451                                            sizeof(struct xlog_op_header));
2452
2453                         len += xlog_write_setup_copy(ticket, ophdr,
2454                                                      iclog->ic_size-log_offset,
2455                                                      reg->i_len,
2456                                                      &copy_off, &copy_len,
2457                                                      &partial_copy,
2458                                                      &partial_copy_len);
2459                         xlog_verify_dest_ptr(log, ptr);
2460
2461                         /*
2462                          * Copy region.
2463                          *
2464                          * Unmount records just log an opheader, so can have
2465                          * empty payloads with no data region to copy. Hence we
2466                          * only copy the payload if the vector says it has data
2467                          * to copy.
2468                          */
2469                         ASSERT(copy_len >= 0);
2470                         if (copy_len > 0) {
2471                                 memcpy(ptr, reg->i_addr + copy_off, copy_len);
2472                                 xlog_write_adv_cnt(&ptr, &len, &log_offset,
2473                                                    copy_len);
2474                         }
2475                         copy_len += start_rec_copy + sizeof(xlog_op_header_t);
2476                         record_cnt++;
2477                         data_cnt += contwr ? copy_len : 0;
2478
2479                         error = xlog_write_copy_finish(log, iclog, flags,
2480                                                        &record_cnt, &data_cnt,
2481                                                        &partial_copy,
2482                                                        &partial_copy_len,
2483                                                        log_offset,
2484                                                        commit_iclog);
2485                         if (error)
2486                                 return error;
2487
2488                         /*
2489                          * if we had a partial copy, we need to get more iclog
2490                          * space but we don't want to increment the region
2491                          * index because there is still more is this region to
2492                          * write.
2493                          *
2494                          * If we completed writing this region, and we flushed
2495                          * the iclog (indicated by resetting of the record
2496                          * count), then we also need to get more log space. If
2497                          * this was the last record, though, we are done and
2498                          * can just return.
2499                          */
2500                         if (partial_copy)
2501                                 break;
2502
2503                         if (++index == lv->lv_niovecs) {
2504 next_lv:
2505                                 lv = lv->lv_next;
2506                                 index = 0;
2507                                 if (lv)
2508                                         vecp = lv->lv_iovecp;
2509                         }
2510                         if (record_cnt == 0 && !ordered) {
2511                                 if (!lv)
2512                                         return 0;
2513                                 break;
2514                         }
2515                 }
2516         }
2517
2518         ASSERT(len == 0);
2519
2520         xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
2521         if (!commit_iclog)
2522                 return xlog_state_release_iclog(log, iclog);
2523
2524         ASSERT(flags & XLOG_COMMIT_TRANS);
2525         *commit_iclog = iclog;
2526         return 0;
2527 }
2528
2529
2530 /*****************************************************************************
2531  *
2532  *              State Machine functions
2533  *
2534  *****************************************************************************
2535  */
2536
2537 /* Clean iclogs starting from the head.  This ordering must be
2538  * maintained, so an iclog doesn't become ACTIVE beyond one that
2539  * is SYNCING.  This is also required to maintain the notion that we use
2540  * a ordered wait queue to hold off would be writers to the log when every
2541  * iclog is trying to sync to disk.
2542  *
2543  * State Change: DIRTY -> ACTIVE
2544  */
2545 STATIC void
2546 xlog_state_clean_log(
2547         struct xlog *log)
2548 {
2549         xlog_in_core_t  *iclog;
2550         int changed = 0;
2551
2552         iclog = log->l_iclog;
2553         do {
2554                 if (iclog->ic_state == XLOG_STATE_DIRTY) {
2555                         iclog->ic_state = XLOG_STATE_ACTIVE;
2556                         iclog->ic_offset       = 0;
2557                         ASSERT(iclog->ic_callback == NULL);
2558                         /*
2559                          * If the number of ops in this iclog indicate it just
2560                          * contains the dummy transaction, we can
2561                          * change state into IDLE (the second time around).
2562                          * Otherwise we should change the state into
2563                          * NEED a dummy.
2564                          * We don't need to cover the dummy.
2565                          */
2566                         if (!changed &&
2567                            (be32_to_cpu(iclog->ic_header.h_num_logops) ==
2568                                         XLOG_COVER_OPS)) {
2569                                 changed = 1;
2570                         } else {
2571                                 /*
2572                                  * We have two dirty iclogs so start over
2573                                  * This could also be num of ops indicates
2574                                  * this is not the dummy going out.
2575                                  */
2576                                 changed = 2;
2577                         }
2578                         iclog->ic_header.h_num_logops = 0;
2579                         memset(iclog->ic_header.h_cycle_data, 0,
2580                               sizeof(iclog->ic_header.h_cycle_data));
2581                         iclog->ic_header.h_lsn = 0;
2582                 } else if (iclog->ic_state == XLOG_STATE_ACTIVE)
2583                         /* do nothing */;
2584                 else
2585                         break;  /* stop cleaning */
2586                 iclog = iclog->ic_next;
2587         } while (iclog != log->l_iclog);
2588
2589         /* log is locked when we are called */
2590         /*
2591          * Change state for the dummy log recording.
2592          * We usually go to NEED. But we go to NEED2 if the changed indicates
2593          * we are done writing the dummy record.
2594          * If we are done with the second dummy recored (DONE2), then
2595          * we go to IDLE.
2596          */
2597         if (changed) {
2598                 switch (log->l_covered_state) {
2599                 case XLOG_STATE_COVER_IDLE:
2600                 case XLOG_STATE_COVER_NEED:
2601                 case XLOG_STATE_COVER_NEED2:
2602                         log->l_covered_state = XLOG_STATE_COVER_NEED;
2603                         break;
2604
2605                 case XLOG_STATE_COVER_DONE:
2606                         if (changed == 1)
2607                                 log->l_covered_state = XLOG_STATE_COVER_NEED2;
2608                         else
2609                                 log->l_covered_state = XLOG_STATE_COVER_NEED;
2610                         break;
2611
2612                 case XLOG_STATE_COVER_DONE2:
2613                         if (changed == 1)
2614                                 log->l_covered_state = XLOG_STATE_COVER_IDLE;
2615                         else
2616                                 log->l_covered_state = XLOG_STATE_COVER_NEED;
2617                         break;
2618
2619                 default:
2620                         ASSERT(0);
2621                 }
2622         }
2623 }       /* xlog_state_clean_log */
2624
2625 STATIC xfs_lsn_t
2626 xlog_get_lowest_lsn(
2627         struct xlog             *log)
2628 {
2629         struct xlog_in_core     *iclog = log->l_iclog;
2630         xfs_lsn_t               lowest_lsn = 0, lsn;
2631
2632         do {
2633                 if (iclog->ic_state & (XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY))
2634                         continue;
2635
2636                 lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2637                 if ((lsn && !lowest_lsn) || XFS_LSN_CMP(lsn, lowest_lsn) < 0)
2638                         lowest_lsn = lsn;
2639         } while ((iclog = iclog->ic_next) != log->l_iclog);
2640
2641         return lowest_lsn;
2642 }
2643
2644 STATIC void
2645 xlog_state_do_callback(
2646         struct xlog             *log,
2647         int                     aborted,
2648         struct xlog_in_core     *ciclog)
2649 {
2650         xlog_in_core_t     *iclog;
2651         xlog_in_core_t     *first_iclog;        /* used to know when we've
2652                                                  * processed all iclogs once */
2653         xfs_log_callback_t *cb, *cb_next;
2654         int                flushcnt = 0;
2655         xfs_lsn_t          lowest_lsn;
2656         int                ioerrors;    /* counter: iclogs with errors */
2657         int                loopdidcallbacks; /* flag: inner loop did callbacks*/
2658         int                funcdidcallbacks; /* flag: function did callbacks */
2659         int                repeats;     /* for issuing console warnings if
2660                                          * looping too many times */
2661         int                wake = 0;
2662
2663         spin_lock(&log->l_icloglock);
2664         first_iclog = iclog = log->l_iclog;
2665         ioerrors = 0;
2666         funcdidcallbacks = 0;
2667         repeats = 0;
2668
2669         do {
2670                 /*
2671                  * Scan all iclogs starting with the one pointed to by the
2672                  * log.  Reset this starting point each time the log is
2673                  * unlocked (during callbacks).
2674                  *
2675                  * Keep looping through iclogs until one full pass is made
2676                  * without running any callbacks.
2677                  */
2678                 first_iclog = log->l_iclog;
2679                 iclog = log->l_iclog;
2680                 loopdidcallbacks = 0;
2681                 repeats++;
2682
2683                 do {
2684
2685                         /* skip all iclogs in the ACTIVE & DIRTY states */
2686                         if (iclog->ic_state &
2687                             (XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY)) {
2688                                 iclog = iclog->ic_next;
2689                                 continue;
2690                         }
2691
2692                         /*
2693                          * Between marking a filesystem SHUTDOWN and stopping
2694                          * the log, we do flush all iclogs to disk (if there
2695                          * wasn't a log I/O error). So, we do want things to
2696                          * go smoothly in case of just a SHUTDOWN  w/o a
2697                          * LOG_IO_ERROR.
2698                          */
2699                         if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
2700                                 /*
2701                                  * Can only perform callbacks in order.  Since
2702                                  * this iclog is not in the DONE_SYNC/
2703                                  * DO_CALLBACK state, we skip the rest and
2704                                  * just try to clean up.  If we set our iclog
2705                                  * to DO_CALLBACK, we will not process it when
2706                                  * we retry since a previous iclog is in the
2707                                  * CALLBACK and the state cannot change since
2708                                  * we are holding the l_icloglock.
2709                                  */
2710                                 if (!(iclog->ic_state &
2711                                         (XLOG_STATE_DONE_SYNC |
2712                                                  XLOG_STATE_DO_CALLBACK))) {
2713                                         if (ciclog && (ciclog->ic_state ==
2714                                                         XLOG_STATE_DONE_SYNC)) {
2715                                                 ciclog->ic_state = XLOG_STATE_DO_CALLBACK;
2716                                         }
2717                                         break;
2718                                 }
2719                                 /*
2720                                  * We now have an iclog that is in either the
2721                                  * DO_CALLBACK or DONE_SYNC states. The other
2722                                  * states (WANT_SYNC, SYNCING, or CALLBACK were
2723                                  * caught by the above if and are going to
2724                                  * clean (i.e. we aren't doing their callbacks)
2725                                  * see the above if.
2726                                  */
2727
2728                                 /*
2729                                  * We will do one more check here to see if we
2730                                  * have chased our tail around.
2731                                  */
2732
2733                                 lowest_lsn = xlog_get_lowest_lsn(log);
2734                                 if (lowest_lsn &&
2735                                     XFS_LSN_CMP(lowest_lsn,
2736                                                 be64_to_cpu(iclog->ic_header.h_lsn)) < 0) {
2737                                         iclog = iclog->ic_next;
2738                                         continue; /* Leave this iclog for
2739                                                    * another thread */
2740                                 }
2741
2742                                 iclog->ic_state = XLOG_STATE_CALLBACK;
2743
2744
2745                                 /*
2746                                  * Completion of a iclog IO does not imply that
2747                                  * a transaction has completed, as transactions
2748                                  * can be large enough to span many iclogs. We
2749                                  * cannot change the tail of the log half way
2750                                  * through a transaction as this may be the only
2751                                  * transaction in the log and moving th etail to
2752                                  * point to the middle of it will prevent
2753                                  * recovery from finding the start of the
2754                                  * transaction. Hence we should only update the
2755                                  * last_sync_lsn if this iclog contains
2756                                  * transaction completion callbacks on it.
2757                                  *
2758                                  * We have to do this before we drop the
2759                                  * icloglock to ensure we are the only one that
2760                                  * can update it.
2761                                  */
2762                                 ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
2763                                         be64_to_cpu(iclog->ic_header.h_lsn)) <= 0);
2764                                 if (iclog->ic_callback)
2765                                         atomic64_set(&log->l_last_sync_lsn,
2766                                                 be64_to_cpu(iclog->ic_header.h_lsn));
2767
2768                         } else
2769                                 ioerrors++;
2770
2771                         spin_unlock(&log->l_icloglock);
2772
2773                         /*
2774                          * Keep processing entries in the callback list until
2775                          * we come around and it is empty.  We need to
2776                          * atomically see that the list is empty and change the
2777                          * state to DIRTY so that we don't miss any more
2778                          * callbacks being added.
2779                          */
2780                         spin_lock(&iclog->ic_callback_lock);
2781                         cb = iclog->ic_callback;
2782                         while (cb) {
2783                                 iclog->ic_callback_tail = &(iclog->ic_callback);
2784                                 iclog->ic_callback = NULL;
2785                                 spin_unlock(&iclog->ic_callback_lock);
2786
2787                                 /* perform callbacks in the order given */
2788                                 for (; cb; cb = cb_next) {
2789                                         cb_next = cb->cb_next;
2790                                         cb->cb_func(cb->cb_arg, aborted);
2791                                 }
2792                                 spin_lock(&iclog->ic_callback_lock);
2793                                 cb = iclog->ic_callback;
2794                         }
2795
2796                         loopdidcallbacks++;
2797                         funcdidcallbacks++;
2798
2799                         spin_lock(&log->l_icloglock);
2800                         ASSERT(iclog->ic_callback == NULL);
2801                         spin_unlock(&iclog->ic_callback_lock);
2802                         if (!(iclog->ic_state & XLOG_STATE_IOERROR))
2803                                 iclog->ic_state = XLOG_STATE_DIRTY;
2804
2805                         /*
2806                          * Transition from DIRTY to ACTIVE if applicable.
2807                          * NOP if STATE_IOERROR.
2808                          */
2809                         xlog_state_clean_log(log);
2810
2811                         /* wake up threads waiting in xfs_log_force() */
2812                         wake_up_all(&iclog->ic_force_wait);
2813
2814                         iclog = iclog->ic_next;
2815                 } while (first_iclog != iclog);
2816
2817                 if (repeats > 5000) {
2818                         flushcnt += repeats;
2819                         repeats = 0;
2820                         xfs_warn(log->l_mp,
2821                                 "%s: possible infinite loop (%d iterations)",
2822                                 __func__, flushcnt);
2823                 }
2824         } while (!ioerrors && loopdidcallbacks);
2825
2826 #ifdef DEBUG
2827         /*
2828          * Make one last gasp attempt to see if iclogs are being left in limbo.
2829          * If the above loop finds an iclog earlier than the current iclog and
2830          * in one of the syncing states, the current iclog is put into
2831          * DO_CALLBACK and the callbacks are deferred to the completion of the
2832          * earlier iclog. Walk the iclogs in order and make sure that no iclog
2833          * is in DO_CALLBACK unless an earlier iclog is in one of the syncing
2834          * states.
2835          *
2836          * Note that SYNCING|IOABORT is a valid state so we cannot just check
2837          * for ic_state == SYNCING.
2838          */
2839         if (funcdidcallbacks) {
2840                 first_iclog = iclog = log->l_iclog;
2841                 do {
2842                         ASSERT(iclog->ic_state != XLOG_STATE_DO_CALLBACK);
2843                         /*
2844                          * Terminate the loop if iclogs are found in states
2845                          * which will cause other threads to clean up iclogs.
2846                          *
2847                          * SYNCING - i/o completion will go through logs
2848                          * DONE_SYNC - interrupt thread should be waiting for
2849                          *              l_icloglock
2850                          * IOERROR - give up hope all ye who enter here
2851                          */
2852                         if (iclog->ic_state == XLOG_STATE_WANT_SYNC ||
2853                             iclog->ic_state & XLOG_STATE_SYNCING ||
2854                             iclog->ic_state == XLOG_STATE_DONE_SYNC ||
2855                             iclog->ic_state == XLOG_STATE_IOERROR )
2856                                 break;
2857                         iclog = iclog->ic_next;
2858                 } while (first_iclog != iclog);
2859         }
2860 #endif
2861
2862         if (log->l_iclog->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_IOERROR))
2863                 wake = 1;
2864         spin_unlock(&log->l_icloglock);
2865
2866         if (wake)
2867                 wake_up_all(&log->l_flush_wait);
2868 }
2869
2870
2871 /*
2872  * Finish transitioning this iclog to the dirty state.
2873  *
2874  * Make sure that we completely execute this routine only when this is
2875  * the last call to the iclog.  There is a good chance that iclog flushes,
2876  * when we reach the end of the physical log, get turned into 2 separate
2877  * calls to bwrite.  Hence, one iclog flush could generate two calls to this
2878  * routine.  By using the reference count bwritecnt, we guarantee that only
2879  * the second completion goes through.
2880  *
2881  * Callbacks could take time, so they are done outside the scope of the
2882  * global state machine log lock.
2883  */
2884 STATIC void
2885 xlog_state_done_syncing(
2886         xlog_in_core_t  *iclog,
2887         int             aborted)
2888 {
2889         struct xlog        *log = iclog->ic_log;
2890
2891         spin_lock(&log->l_icloglock);
2892
2893         ASSERT(iclog->ic_state == XLOG_STATE_SYNCING ||
2894                iclog->ic_state == XLOG_STATE_IOERROR);
2895         ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
2896         ASSERT(iclog->ic_bwritecnt == 1 || iclog->ic_bwritecnt == 2);
2897
2898
2899         /*
2900          * If we got an error, either on the first buffer, or in the case of
2901          * split log writes, on the second, we mark ALL iclogs STATE_IOERROR,
2902          * and none should ever be attempted to be written to disk
2903          * again.
2904          */
2905         if (iclog->ic_state != XLOG_STATE_IOERROR) {
2906                 if (--iclog->ic_bwritecnt == 1) {
2907                         spin_unlock(&log->l_icloglock);
2908                         return;
2909                 }
2910                 iclog->ic_state = XLOG_STATE_DONE_SYNC;
2911         }
2912
2913         /*
2914          * Someone could be sleeping prior to writing out the next
2915          * iclog buffer, we wake them all, one will get to do the
2916          * I/O, the others get to wait for the result.
2917          */
2918         wake_up_all(&iclog->ic_write_wait);
2919         spin_unlock(&log->l_icloglock);
2920         xlog_state_do_callback(log, aborted, iclog);    /* also cleans log */
2921 }       /* xlog_state_done_syncing */
2922
2923
2924 /*
2925  * If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
2926  * sleep.  We wait on the flush queue on the head iclog as that should be
2927  * the first iclog to complete flushing. Hence if all iclogs are syncing,
2928  * we will wait here and all new writes will sleep until a sync completes.
2929  *
2930  * The in-core logs are used in a circular fashion. They are not used
2931  * out-of-order even when an iclog past the head is free.
2932  *
2933  * return:
2934  *      * log_offset where xlog_write() can start writing into the in-core
2935  *              log's data space.
2936  *      * in-core log pointer to which xlog_write() should write.
2937  *      * boolean indicating this is a continued write to an in-core log.
2938  *              If this is the last write, then the in-core log's offset field
2939  *              needs to be incremented, depending on the amount of data which
2940  *              is copied.
2941  */
2942 STATIC int
2943 xlog_state_get_iclog_space(
2944         struct xlog             *log,
2945         int                     len,
2946         struct xlog_in_core     **iclogp,
2947         struct xlog_ticket      *ticket,
2948         int                     *continued_write,
2949         int                     *logoffsetp)
2950 {
2951         int               log_offset;
2952         xlog_rec_header_t *head;
2953         xlog_in_core_t    *iclog;
2954         int               error;
2955
2956 restart:
2957         spin_lock(&log->l_icloglock);
2958         if (XLOG_FORCED_SHUTDOWN(log)) {
2959                 spin_unlock(&log->l_icloglock);
2960                 return -EIO;
2961         }
2962
2963         iclog = log->l_iclog;
2964         if (iclog->ic_state != XLOG_STATE_ACTIVE) {
2965                 XFS_STATS_INC(log->l_mp, xs_log_noiclogs);
2966
2967                 /* Wait for log writes to have flushed */
2968                 xlog_wait(&log->l_flush_wait, &log->l_icloglock);
2969                 goto restart;
2970         }
2971
2972         head = &iclog->ic_header;
2973
2974         atomic_inc(&iclog->ic_refcnt);  /* prevents sync */
2975         log_offset = iclog->ic_offset;
2976
2977         /* On the 1st write to an iclog, figure out lsn.  This works
2978          * if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
2979          * committing to.  If the offset is set, that's how many blocks
2980          * must be written.
2981          */
2982         if (log_offset == 0) {
2983                 ticket->t_curr_res -= log->l_iclog_hsize;
2984                 xlog_tic_add_region(ticket,
2985                                     log->l_iclog_hsize,
2986                                     XLOG_REG_TYPE_LRHEADER);
2987                 head->h_cycle = cpu_to_be32(log->l_curr_cycle);
2988                 head->h_lsn = cpu_to_be64(
2989                         xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
2990                 ASSERT(log->l_curr_block >= 0);
2991         }
2992
2993         /* If there is enough room to write everything, then do it.  Otherwise,
2994          * claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
2995          * bit is on, so this will get flushed out.  Don't update ic_offset
2996          * until you know exactly how many bytes get copied.  Therefore, wait
2997          * until later to update ic_offset.
2998          *
2999          * xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
3000          * can fit into remaining data section.
3001          */
3002         if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
3003                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
3004
3005                 /*
3006                  * If I'm the only one writing to this iclog, sync it to disk.
3007                  * We need to do an atomic compare and decrement here to avoid
3008                  * racing with concurrent atomic_dec_and_lock() calls in
3009                  * xlog_state_release_iclog() when there is more than one
3010                  * reference to the iclog.
3011                  */
3012                 if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1)) {
3013                         /* we are the only one */
3014                         spin_unlock(&log->l_icloglock);
3015                         error = xlog_state_release_iclog(log, iclog);
3016                         if (error)
3017                                 return error;
3018                 } else {
3019                         spin_unlock(&log->l_icloglock);
3020                 }
3021                 goto restart;
3022         }
3023
3024         /* Do we have enough room to write the full amount in the remainder
3025          * of this iclog?  Or must we continue a write on the next iclog and
3026          * mark this iclog as completely taken?  In the case where we switch
3027          * iclogs (to mark it taken), this particular iclog will release/sync
3028          * to disk in xlog_write().
3029          */
3030         if (len <= iclog->ic_size - iclog->ic_offset) {
3031                 *continued_write = 0;
3032                 iclog->ic_offset += len;
3033         } else {
3034                 *continued_write = 1;
3035                 xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
3036         }
3037         *iclogp = iclog;
3038
3039         ASSERT(iclog->ic_offset <= iclog->ic_size);
3040         spin_unlock(&log->l_icloglock);
3041
3042         *logoffsetp = log_offset;
3043         return 0;
3044 }       /* xlog_state_get_iclog_space */
3045
3046 /* The first cnt-1 times through here we don't need to
3047  * move the grant write head because the permanent
3048  * reservation has reserved cnt times the unit amount.
3049  * Release part of current permanent unit reservation and
3050  * reset current reservation to be one units worth.  Also
3051  * move grant reservation head forward.
3052  */
3053 STATIC void
3054 xlog_regrant_reserve_log_space(
3055         struct xlog             *log,
3056         struct xlog_ticket      *ticket)
3057 {
3058         trace_xfs_log_regrant_reserve_enter(log, ticket);
3059
3060         if (ticket->t_cnt > 0)
3061                 ticket->t_cnt--;
3062
3063         xlog_grant_sub_space(log, &log->l_reserve_head.grant,
3064                                         ticket->t_curr_res);
3065         xlog_grant_sub_space(log, &log->l_write_head.grant,
3066                                         ticket->t_curr_res);
3067         ticket->t_curr_res = ticket->t_unit_res;
3068         xlog_tic_reset_res(ticket);
3069
3070         trace_xfs_log_regrant_reserve_sub(log, ticket);
3071
3072         /* just return if we still have some of the pre-reserved space */
3073         if (ticket->t_cnt > 0)
3074                 return;
3075
3076         xlog_grant_add_space(log, &log->l_reserve_head.grant,
3077                                         ticket->t_unit_res);
3078
3079         trace_xfs_log_regrant_reserve_exit(log, ticket);
3080
3081         ticket->t_curr_res = ticket->t_unit_res;
3082         xlog_tic_reset_res(ticket);
3083 }       /* xlog_regrant_reserve_log_space */
3084
3085
3086 /*
3087  * Give back the space left from a reservation.
3088  *
3089  * All the information we need to make a correct determination of space left
3090  * is present.  For non-permanent reservations, things are quite easy.  The
3091  * count should have been decremented to zero.  We only need to deal with the
3092  * space remaining in the current reservation part of the ticket.  If the
3093  * ticket contains a permanent reservation, there may be left over space which
3094  * needs to be released.  A count of N means that N-1 refills of the current
3095  * reservation can be done before we need to ask for more space.  The first
3096  * one goes to fill up the first current reservation.  Once we run out of
3097  * space, the count will stay at zero and the only space remaining will be
3098  * in the current reservation field.
3099  */
3100 STATIC void
3101 xlog_ungrant_log_space(
3102         struct xlog             *log,
3103         struct xlog_ticket      *ticket)
3104 {
3105         int     bytes;
3106
3107         if (ticket->t_cnt > 0)
3108                 ticket->t_cnt--;
3109
3110         trace_xfs_log_ungrant_enter(log, ticket);
3111         trace_xfs_log_ungrant_sub(log, ticket);
3112
3113         /*
3114          * If this is a permanent reservation ticket, we may be able to free
3115          * up more space based on the remaining count.
3116          */
3117         bytes = ticket->t_curr_res;
3118         if (ticket->t_cnt > 0) {
3119                 ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
3120                 bytes += ticket->t_unit_res*ticket->t_cnt;
3121         }
3122
3123         xlog_grant_sub_space(log, &log->l_reserve_head.grant, bytes);
3124         xlog_grant_sub_space(log, &log->l_write_head.grant, bytes);
3125
3126         trace_xfs_log_ungrant_exit(log, ticket);
3127
3128         xfs_log_space_wake(log->l_mp);
3129 }
3130
3131 /*
3132  * Flush iclog to disk if this is the last reference to the given iclog and
3133  * the WANT_SYNC bit is set.
3134  *
3135  * When this function is entered, the iclog is not necessarily in the
3136  * WANT_SYNC state.  It may be sitting around waiting to get filled.
3137  *
3138  *
3139  */
3140 STATIC int
3141 xlog_state_release_iclog(
3142         struct xlog             *log,
3143         struct xlog_in_core     *iclog)
3144 {
3145         int             sync = 0;       /* do we sync? */
3146
3147         if (iclog->ic_state & XLOG_STATE_IOERROR)
3148                 return -EIO;
3149
3150         ASSERT(atomic_read(&iclog->ic_refcnt) > 0);
3151         if (!atomic_dec_and_lock(&iclog->ic_refcnt, &log->l_icloglock))
3152                 return 0;
3153
3154         if (iclog->ic_state & XLOG_STATE_IOERROR) {
3155                 spin_unlock(&log->l_icloglock);
3156                 return -EIO;
3157         }
3158         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE ||
3159                iclog->ic_state == XLOG_STATE_WANT_SYNC);
3160
3161         if (iclog->ic_state == XLOG_STATE_WANT_SYNC) {
3162                 /* update tail before writing to iclog */
3163                 xfs_lsn_t tail_lsn = xlog_assign_tail_lsn(log->l_mp);
3164                 sync++;
3165                 iclog->ic_state = XLOG_STATE_SYNCING;
3166                 iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn);
3167                 xlog_verify_tail_lsn(log, iclog, tail_lsn);
3168                 /* cycle incremented when incrementing curr_block */
3169         }
3170         spin_unlock(&log->l_icloglock);
3171
3172         /*
3173          * We let the log lock go, so it's possible that we hit a log I/O
3174          * error or some other SHUTDOWN condition that marks the iclog
3175          * as XLOG_STATE_IOERROR before the bwrite. However, we know that
3176          * this iclog has consistent data, so we ignore IOERROR
3177          * flags after this point.
3178          */
3179         if (sync)
3180                 xlog_sync(log, iclog);
3181         return 0;
3182 }       /* xlog_state_release_iclog */
3183
3184
3185 /*
3186  * This routine will mark the current iclog in the ring as WANT_SYNC
3187  * and move the current iclog pointer to the next iclog in the ring.
3188  * When this routine is called from xlog_state_get_iclog_space(), the
3189  * exact size of the iclog has not yet been determined.  All we know is
3190  * that every data block.  We have run out of space in this log record.
3191  */
3192 STATIC void
3193 xlog_state_switch_iclogs(
3194         struct xlog             *log,
3195         struct xlog_in_core     *iclog,
3196         int                     eventual_size)
3197 {
3198         ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
3199         if (!eventual_size)
3200                 eventual_size = iclog->ic_offset;
3201         iclog->ic_state = XLOG_STATE_WANT_SYNC;
3202         iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
3203         log->l_prev_block = log->l_curr_block;
3204         log->l_prev_cycle = log->l_curr_cycle;
3205
3206         /* roll log?: ic_offset changed later */
3207         log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
3208
3209         /* Round up to next log-sunit */
3210         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
3211             log->l_mp->m_sb.sb_logsunit > 1) {
3212                 uint32_t sunit_bb = BTOBB(log->l_mp->m_sb.sb_logsunit);
3213                 log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
3214         }
3215
3216         if (log->l_curr_block >= log->l_logBBsize) {
3217                 /*
3218                  * Rewind the current block before the cycle is bumped to make
3219                  * sure that the combined LSN never transiently moves forward
3220                  * when the log wraps to the next cycle. This is to support the
3221                  * unlocked sample of these fields from xlog_valid_lsn(). Most
3222                  * other cases should acquire l_icloglock.
3223                  */
3224                 log->l_curr_block -= log->l_logBBsize;
3225                 ASSERT(log->l_curr_block >= 0);
3226                 smp_wmb();
3227                 log->l_curr_cycle++;
3228                 if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
3229                         log->l_curr_cycle++;
3230         }
3231         ASSERT(iclog == log->l_iclog);
3232         log->l_iclog = iclog->ic_next;
3233 }       /* xlog_state_switch_iclogs */
3234
3235 /*
3236  * Write out all data in the in-core log as of this exact moment in time.
3237  *
3238  * Data may be written to the in-core log during this call.  However,
3239  * we don't guarantee this data will be written out.  A change from past
3240  * implementation means this routine will *not* write out zero length LRs.
3241  *
3242  * Basically, we try and perform an intelligent scan of the in-core logs.
3243  * If we determine there is no flushable data, we just return.  There is no
3244  * flushable data if:
3245  *
3246  *      1. the current iclog is active and has no data; the previous iclog
3247  *              is in the active or dirty state.
3248  *      2. the current iclog is drity, and the previous iclog is in the
3249  *              active or dirty state.
3250  *
3251  * We may sleep if:
3252  *
3253  *      1. the current iclog is not in the active nor dirty state.
3254  *      2. the current iclog dirty, and the previous iclog is not in the
3255  *              active nor dirty state.
3256  *      3. the current iclog is active, and there is another thread writing
3257  *              to this particular iclog.
3258  *      4. a) the current iclog is active and has no other writers
3259  *         b) when we return from flushing out this iclog, it is still
3260  *              not in the active nor dirty state.
3261  */
3262 int
3263 xfs_log_force(
3264         struct xfs_mount        *mp,
3265         uint                    flags)
3266 {
3267         struct xlog             *log = mp->m_log;
3268         struct xlog_in_core     *iclog;
3269         xfs_lsn_t               lsn;
3270
3271         XFS_STATS_INC(mp, xs_log_force);
3272         trace_xfs_log_force(mp, 0, _RET_IP_);
3273
3274         xlog_cil_force(log);
3275
3276         spin_lock(&log->l_icloglock);
3277         iclog = log->l_iclog;
3278         if (iclog->ic_state & XLOG_STATE_IOERROR)
3279                 goto out_error;
3280
3281         if (iclog->ic_state == XLOG_STATE_DIRTY ||
3282             (iclog->ic_state == XLOG_STATE_ACTIVE &&
3283              atomic_read(&iclog->ic_refcnt) == 0 && iclog->ic_offset == 0)) {
3284                 /*
3285                  * If the head is dirty or (active and empty), then we need to
3286                  * look at the previous iclog.
3287                  *
3288                  * If the previous iclog is active or dirty we are done.  There
3289                  * is nothing to sync out. Otherwise, we attach ourselves to the
3290                  * previous iclog and go to sleep.
3291                  */
3292                 iclog = iclog->ic_prev;
3293                 if (iclog->ic_state == XLOG_STATE_ACTIVE ||
3294                     iclog->ic_state == XLOG_STATE_DIRTY)
3295                         goto out_unlock;
3296         } else if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3297                 if (atomic_read(&iclog->ic_refcnt) == 0) {
3298                         /*
3299                          * We are the only one with access to this iclog.
3300                          *
3301                          * Flush it out now.  There should be a roundoff of zero
3302                          * to show that someone has already taken care of the
3303                          * roundoff from the previous sync.
3304                          */
3305                         atomic_inc(&iclog->ic_refcnt);
3306                         lsn = be64_to_cpu(iclog->ic_header.h_lsn);
3307                         xlog_state_switch_iclogs(log, iclog, 0);
3308                         spin_unlock(&log->l_icloglock);
3309
3310                         if (xlog_state_release_iclog(log, iclog))
3311                                 return -EIO;
3312
3313                         spin_lock(&log->l_icloglock);
3314                         if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn ||
3315                             iclog->ic_state == XLOG_STATE_DIRTY)
3316                                 goto out_unlock;
3317                 } else {
3318                         /*
3319                          * Someone else is writing to this iclog.
3320                          *
3321                          * Use its call to flush out the data.  However, the
3322                          * other thread may not force out this LR, so we mark
3323                          * it WANT_SYNC.
3324                          */
3325                         xlog_state_switch_iclogs(log, iclog, 0);
3326                 }
3327         } else {
3328                 /*
3329                  * If the head iclog is not active nor dirty, we just attach
3330                  * ourselves to the head and go to sleep if necessary.
3331                  */
3332                 ;
3333         }
3334
3335         if (!(flags & XFS_LOG_SYNC))
3336                 goto out_unlock;
3337
3338         if (iclog->ic_state & XLOG_STATE_IOERROR)
3339                 goto out_error;
3340         XFS_STATS_INC(mp, xs_log_force_sleep);
3341         xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
3342         if (iclog->ic_state & XLOG_STATE_IOERROR)
3343                 return -EIO;
3344         return 0;
3345
3346 out_unlock:
3347         spin_unlock(&log->l_icloglock);
3348         return 0;
3349 out_error:
3350         spin_unlock(&log->l_icloglock);
3351         return -EIO;
3352 }
3353
3354 static int
3355 __xfs_log_force_lsn(
3356         struct xfs_mount        *mp,
3357         xfs_lsn_t               lsn,
3358         uint                    flags,
3359         int                     *log_flushed,
3360         bool                    already_slept)
3361 {
3362         struct xlog             *log = mp->m_log;
3363         struct xlog_in_core     *iclog;
3364
3365         spin_lock(&log->l_icloglock);
3366         iclog = log->l_iclog;
3367         if (iclog->ic_state & XLOG_STATE_IOERROR)
3368                 goto out_error;
3369
3370         while (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
3371                 iclog = iclog->ic_next;
3372                 if (iclog == log->l_iclog)
3373                         goto out_unlock;
3374         }
3375
3376         if (iclog->ic_state == XLOG_STATE_DIRTY)
3377                 goto out_unlock;
3378
3379         if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3380                 /*
3381                  * We sleep here if we haven't already slept (e.g. this is the
3382                  * first time we've looked at the correct iclog buf) and the
3383                  * buffer before us is going to be sync'ed.  The reason for this
3384                  * is that if we are doing sync transactions here, by waiting
3385                  * for the previous I/O to complete, we can allow a few more
3386                  * transactions into this iclog before we close it down.
3387                  *
3388                  * Otherwise, we mark the buffer WANT_SYNC, and bump up the
3389                  * refcnt so we can release the log (which drops the ref count).
3390                  * The state switch keeps new transaction commits from using
3391                  * this buffer.  When the current commits finish writing into
3392                  * the buffer, the refcount will drop to zero and the buffer
3393                  * will go out then.
3394                  */
3395                 if (!already_slept &&
3396                     (iclog->ic_prev->ic_state &
3397                      (XLOG_STATE_WANT_SYNC | XLOG_STATE_SYNCING))) {
3398                         ASSERT(!(iclog->ic_state & XLOG_STATE_IOERROR));
3399
3400                         XFS_STATS_INC(mp, xs_log_force_sleep);
3401
3402                         xlog_wait(&iclog->ic_prev->ic_write_wait,
3403                                         &log->l_icloglock);
3404                         return -EAGAIN;
3405                 }
3406                 atomic_inc(&iclog->ic_refcnt);
3407                 xlog_state_switch_iclogs(log, iclog, 0);
3408                 spin_unlock(&log->l_icloglock);
3409                 if (xlog_state_release_iclog(log, iclog))
3410                         return -EIO;
3411                 if (log_flushed)
3412                         *log_flushed = 1;
3413                 spin_lock(&log->l_icloglock);
3414         }
3415
3416         if (!(flags & XFS_LOG_SYNC) ||
3417             (iclog->ic_state & (XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY)))
3418                 goto out_unlock;
3419
3420         if (iclog->ic_state & XLOG_STATE_IOERROR)
3421                 goto out_error;
3422
3423         XFS_STATS_INC(mp, xs_log_force_sleep);
3424         xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
3425         if (iclog->ic_state & XLOG_STATE_IOERROR)
3426                 return -EIO;
3427         return 0;
3428
3429 out_unlock:
3430         spin_unlock(&log->l_icloglock);
3431         return 0;
3432 out_error:
3433         spin_unlock(&log->l_icloglock);
3434         return -EIO;
3435 }
3436
3437 /*
3438  * Force the in-core log to disk for a specific LSN.
3439  *
3440  * Find in-core log with lsn.
3441  *      If it is in the DIRTY state, just return.
3442  *      If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
3443  *              state and go to sleep or return.
3444  *      If it is in any other state, go to sleep or return.
3445  *
3446  * Synchronous forces are implemented with a wait queue.  All callers trying
3447  * to force a given lsn to disk must wait on the queue attached to the
3448  * specific in-core log.  When given in-core log finally completes its write
3449  * to disk, that thread will wake up all threads waiting on the queue.
3450  */
3451 int
3452 xfs_log_force_lsn(
3453         struct xfs_mount        *mp,
3454         xfs_lsn_t               lsn,
3455         uint                    flags,
3456         int                     *log_flushed)
3457 {
3458         int                     ret;
3459         ASSERT(lsn != 0);
3460
3461         XFS_STATS_INC(mp, xs_log_force);
3462         trace_xfs_log_force(mp, lsn, _RET_IP_);
3463
3464         lsn = xlog_cil_force_lsn(mp->m_log, lsn);
3465         if (lsn == NULLCOMMITLSN)
3466                 return 0;
3467
3468         ret = __xfs_log_force_lsn(mp, lsn, flags, log_flushed, false);
3469         if (ret == -EAGAIN)
3470                 ret = __xfs_log_force_lsn(mp, lsn, flags, log_flushed, true);
3471         return ret;
3472 }
3473
3474 /*
3475  * Called when we want to mark the current iclog as being ready to sync to
3476  * disk.
3477  */
3478 STATIC void
3479 xlog_state_want_sync(
3480         struct xlog             *log,
3481         struct xlog_in_core     *iclog)
3482 {
3483         assert_spin_locked(&log->l_icloglock);
3484
3485         if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3486                 xlog_state_switch_iclogs(log, iclog, 0);
3487         } else {
3488                 ASSERT(iclog->ic_state &
3489                         (XLOG_STATE_WANT_SYNC|XLOG_STATE_IOERROR));
3490         }
3491 }
3492
3493
3494 /*****************************************************************************
3495  *
3496  *              TICKET functions
3497  *
3498  *****************************************************************************
3499  */
3500
3501 /*
3502  * Free a used ticket when its refcount falls to zero.
3503  */
3504 void
3505 xfs_log_ticket_put(
3506         xlog_ticket_t   *ticket)
3507 {
3508         ASSERT(atomic_read(&ticket->t_ref) > 0);
3509         if (atomic_dec_and_test(&ticket->t_ref))
3510                 kmem_zone_free(xfs_log_ticket_zone, ticket);
3511 }
3512
3513 xlog_ticket_t *
3514 xfs_log_ticket_get(
3515         xlog_ticket_t   *ticket)
3516 {
3517         ASSERT(atomic_read(&ticket->t_ref) > 0);
3518         atomic_inc(&ticket->t_ref);
3519         return ticket;
3520 }
3521
3522 /*
3523  * Figure out the total log space unit (in bytes) that would be
3524  * required for a log ticket.
3525  */
3526 int
3527 xfs_log_calc_unit_res(
3528         struct xfs_mount        *mp,
3529         int                     unit_bytes)
3530 {
3531         struct xlog             *log = mp->m_log;
3532         int                     iclog_space;
3533         uint                    num_headers;
3534
3535         /*
3536          * Permanent reservations have up to 'cnt'-1 active log operations
3537          * in the log.  A unit in this case is the amount of space for one
3538          * of these log operations.  Normal reservations have a cnt of 1
3539          * and their unit amount is the total amount of space required.
3540          *
3541          * The following lines of code account for non-transaction data
3542          * which occupy space in the on-disk log.
3543          *
3544          * Normal form of a transaction is:
3545          * <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
3546          * and then there are LR hdrs, split-recs and roundoff at end of syncs.
3547          *
3548          * We need to account for all the leadup data and trailer data
3549          * around the transaction data.
3550          * And then we need to account for the worst case in terms of using
3551          * more space.
3552          * The worst case will happen if:
3553          * - the placement of the transaction happens to be such that the
3554          *   roundoff is at its maximum
3555          * - the transaction data is synced before the commit record is synced
3556          *   i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
3557          *   Therefore the commit record is in its own Log Record.
3558          *   This can happen as the commit record is called with its
3559          *   own region to xlog_write().
3560          *   This then means that in the worst case, roundoff can happen for
3561          *   the commit-rec as well.
3562          *   The commit-rec is smaller than padding in this scenario and so it is
3563          *   not added separately.
3564          */
3565
3566         /* for trans header */
3567         unit_bytes += sizeof(xlog_op_header_t);
3568         unit_bytes += sizeof(xfs_trans_header_t);
3569
3570         /* for start-rec */
3571         unit_bytes += sizeof(xlog_op_header_t);
3572
3573         /*
3574          * for LR headers - the space for data in an iclog is the size minus
3575          * the space used for the headers. If we use the iclog size, then we
3576          * undercalculate the number of headers required.
3577          *
3578          * Furthermore - the addition of op headers for split-recs might
3579          * increase the space required enough to require more log and op
3580          * headers, so take that into account too.
3581          *
3582          * IMPORTANT: This reservation makes the assumption that if this
3583          * transaction is the first in an iclog and hence has the LR headers
3584          * accounted to it, then the remaining space in the iclog is
3585          * exclusively for this transaction.  i.e. if the transaction is larger
3586          * than the iclog, it will be the only thing in that iclog.
3587          * Fundamentally, this means we must pass the entire log vector to
3588          * xlog_write to guarantee this.
3589          */
3590         iclog_space = log->l_iclog_size - log->l_iclog_hsize;
3591         num_headers = howmany(unit_bytes, iclog_space);
3592
3593         /* for split-recs - ophdrs added when data split over LRs */
3594         unit_bytes += sizeof(xlog_op_header_t) * num_headers;
3595
3596         /* add extra header reservations if we overrun */
3597         while (!num_headers ||
3598                howmany(unit_bytes, iclog_space) > num_headers) {
3599                 unit_bytes += sizeof(xlog_op_header_t);
3600                 num_headers++;
3601         }
3602         unit_bytes += log->l_iclog_hsize * num_headers;
3603
3604         /* for commit-rec LR header - note: padding will subsume the ophdr */
3605         unit_bytes += log->l_iclog_hsize;
3606
3607         /* for roundoff padding for transaction data and one for commit record */
3608         if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1) {
3609                 /* log su roundoff */
3610                 unit_bytes += 2 * mp->m_sb.sb_logsunit;
3611         } else {
3612                 /* BB roundoff */
3613                 unit_bytes += 2 * BBSIZE;
3614         }
3615
3616         return unit_bytes;
3617 }
3618
3619 /*
3620  * Allocate and initialise a new log ticket.
3621  */
3622 struct xlog_ticket *
3623 xlog_ticket_alloc(
3624         struct xlog             *log,
3625         int                     unit_bytes,
3626         int                     cnt,
3627         char                    client,
3628         bool                    permanent,
3629         xfs_km_flags_t          alloc_flags)
3630 {
3631         struct xlog_ticket      *tic;
3632         int                     unit_res;
3633
3634         tic = kmem_zone_zalloc(xfs_log_ticket_zone, alloc_flags);
3635         if (!tic)
3636                 return NULL;
3637
3638         unit_res = xfs_log_calc_unit_res(log->l_mp, unit_bytes);
3639
3640         atomic_set(&tic->t_ref, 1);
3641         tic->t_task             = current;
3642         INIT_LIST_HEAD(&tic->t_queue);
3643         tic->t_unit_res         = unit_res;
3644         tic->t_curr_res         = unit_res;
3645         tic->t_cnt              = cnt;
3646         tic->t_ocnt             = cnt;
3647         tic->t_tid              = prandom_u32();
3648         tic->t_clientid         = client;
3649         tic->t_flags            = XLOG_TIC_INITED;
3650         if (permanent)
3651                 tic->t_flags |= XLOG_TIC_PERM_RESERV;
3652
3653         xlog_tic_reset_res(tic);
3654
3655         return tic;
3656 }
3657
3658
3659 /******************************************************************************
3660  *
3661  *              Log debug routines
3662  *
3663  ******************************************************************************
3664  */
3665 #if defined(DEBUG)
3666 /*
3667  * Make sure that the destination ptr is within the valid data region of
3668  * one of the iclogs.  This uses backup pointers stored in a different
3669  * part of the log in case we trash the log structure.
3670  */
3671 STATIC void
3672 xlog_verify_dest_ptr(
3673         struct xlog     *log,
3674         void            *ptr)
3675 {
3676         int i;
3677         int good_ptr = 0;
3678
3679         for (i = 0; i < log->l_iclog_bufs; i++) {
3680                 if (ptr >= log->l_iclog_bak[i] &&
3681                     ptr <= log->l_iclog_bak[i] + log->l_iclog_size)
3682                         good_ptr++;
3683         }
3684
3685         if (!good_ptr)
3686                 xfs_emerg(log->l_mp, "%s: invalid ptr", __func__);
3687 }
3688
3689 /*
3690  * Check to make sure the grant write head didn't just over lap the tail.  If
3691  * the cycles are the same, we can't be overlapping.  Otherwise, make sure that
3692  * the cycles differ by exactly one and check the byte count.
3693  *
3694  * This check is run unlocked, so can give false positives. Rather than assert
3695  * on failures, use a warn-once flag and a panic tag to allow the admin to
3696  * determine if they want to panic the machine when such an error occurs. For
3697  * debug kernels this will have the same effect as using an assert but, unlinke
3698  * an assert, it can be turned off at runtime.
3699  */
3700 STATIC void
3701 xlog_verify_grant_tail(
3702         struct xlog     *log)
3703 {
3704         int             tail_cycle, tail_blocks;
3705         int             cycle, space;
3706
3707         xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &space);
3708         xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
3709         if (tail_cycle != cycle) {
3710                 if (cycle - 1 != tail_cycle &&
3711                     !(log->l_flags & XLOG_TAIL_WARN)) {
3712                         xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3713                                 "%s: cycle - 1 != tail_cycle", __func__);
3714                         log->l_flags |= XLOG_TAIL_WARN;
3715                 }
3716
3717                 if (space > BBTOB(tail_blocks) &&
3718                     !(log->l_flags & XLOG_TAIL_WARN)) {
3719                         xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3720                                 "%s: space > BBTOB(tail_blocks)", __func__);
3721                         log->l_flags |= XLOG_TAIL_WARN;
3722                 }
3723         }
3724 }
3725
3726 /* check if it will fit */
3727 STATIC void
3728 xlog_verify_tail_lsn(
3729         struct xlog             *log,
3730         struct xlog_in_core     *iclog,
3731         xfs_lsn_t               tail_lsn)
3732 {
3733     int blocks;
3734
3735     if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
3736         blocks =
3737             log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
3738         if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
3739                 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3740     } else {
3741         ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
3742
3743         if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
3744                 xfs_emerg(log->l_mp, "%s: tail wrapped", __func__);
3745
3746         blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
3747         if (blocks < BTOBB(iclog->ic_offset) + 1)
3748                 xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3749     }
3750 }       /* xlog_verify_tail_lsn */
3751
3752 /*
3753  * Perform a number of checks on the iclog before writing to disk.
3754  *
3755  * 1. Make sure the iclogs are still circular
3756  * 2. Make sure we have a good magic number
3757  * 3. Make sure we don't have magic numbers in the data
3758  * 4. Check fields of each log operation header for:
3759  *      A. Valid client identifier
3760  *      B. tid ptr value falls in valid ptr space (user space code)
3761  *      C. Length in log record header is correct according to the
3762  *              individual operation headers within record.
3763  * 5. When a bwrite will occur within 5 blocks of the front of the physical
3764  *      log, check the preceding blocks of the physical log to make sure all
3765  *      the cycle numbers agree with the current cycle number.
3766  */
3767 STATIC void
3768 xlog_verify_iclog(
3769         struct xlog             *log,
3770         struct xlog_in_core     *iclog,
3771         int                     count,
3772         bool                    syncing)
3773 {
3774         xlog_op_header_t        *ophead;
3775         xlog_in_core_t          *icptr;
3776         xlog_in_core_2_t        *xhdr;
3777         void                    *base_ptr, *ptr, *p;
3778         ptrdiff_t               field_offset;
3779         uint8_t                 clientid;
3780         int                     len, i, j, k, op_len;
3781         int                     idx;
3782
3783         /* check validity of iclog pointers */
3784         spin_lock(&log->l_icloglock);
3785         icptr = log->l_iclog;
3786         for (i = 0; i < log->l_iclog_bufs; i++, icptr = icptr->ic_next)
3787                 ASSERT(icptr);
3788
3789         if (icptr != log->l_iclog)
3790                 xfs_emerg(log->l_mp, "%s: corrupt iclog ring", __func__);
3791         spin_unlock(&log->l_icloglock);
3792
3793         /* check log magic numbers */
3794         if (iclog->ic_header.h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3795                 xfs_emerg(log->l_mp, "%s: invalid magic num", __func__);
3796
3797         base_ptr = ptr = &iclog->ic_header;
3798         p = &iclog->ic_header;
3799         for (ptr += BBSIZE; ptr < base_ptr + count; ptr += BBSIZE) {
3800                 if (*(__be32 *)ptr == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3801                         xfs_emerg(log->l_mp, "%s: unexpected magic num",
3802                                 __func__);
3803         }
3804
3805         /* check fields */
3806         len = be32_to_cpu(iclog->ic_header.h_num_logops);
3807         base_ptr = ptr = iclog->ic_datap;
3808         ophead = ptr;
3809         xhdr = iclog->ic_data;
3810         for (i = 0; i < len; i++) {
3811                 ophead = ptr;
3812
3813                 /* clientid is only 1 byte */
3814                 p = &ophead->oh_clientid;
3815                 field_offset = p - base_ptr;
3816                 if (!syncing || (field_offset & 0x1ff)) {
3817                         clientid = ophead->oh_clientid;
3818                 } else {
3819                         idx = BTOBBT((char *)&ophead->oh_clientid - iclog->ic_datap);
3820                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3821                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3822                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3823                                 clientid = xlog_get_client_id(
3824                                         xhdr[j].hic_xheader.xh_cycle_data[k]);
3825                         } else {
3826                                 clientid = xlog_get_client_id(
3827                                         iclog->ic_header.h_cycle_data[idx]);
3828                         }
3829                 }
3830                 if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
3831                         xfs_warn(log->l_mp,
3832                                 "%s: invalid clientid %d op "PTR_FMT" offset 0x%lx",
3833                                 __func__, clientid, ophead,
3834                                 (unsigned long)field_offset);
3835
3836                 /* check length */
3837                 p = &ophead->oh_len;
3838                 field_offset = p - base_ptr;
3839                 if (!syncing || (field_offset & 0x1ff)) {
3840                         op_len = be32_to_cpu(ophead->oh_len);
3841                 } else {
3842                         idx = BTOBBT((uintptr_t)&ophead->oh_len -
3843                                     (uintptr_t)iclog->ic_datap);
3844                         if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3845                                 j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3846                                 k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3847                                 op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
3848                         } else {
3849                                 op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
3850                         }
3851                 }
3852                 ptr += sizeof(xlog_op_header_t) + op_len;
3853         }
3854 }       /* xlog_verify_iclog */
3855 #endif
3856
3857 /*
3858  * Mark all iclogs IOERROR. l_icloglock is held by the caller.
3859  */
3860 STATIC int
3861 xlog_state_ioerror(
3862         struct xlog     *log)
3863 {
3864         xlog_in_core_t  *iclog, *ic;
3865
3866         iclog = log->l_iclog;
3867         if (! (iclog->ic_state & XLOG_STATE_IOERROR)) {
3868                 /*
3869                  * Mark all the incore logs IOERROR.
3870                  * From now on, no log flushes will result.
3871                  */
3872                 ic = iclog;
3873                 do {
3874                         ic->ic_state = XLOG_STATE_IOERROR;
3875                         ic = ic->ic_next;
3876                 } while (ic != iclog);
3877                 return 0;
3878         }
3879         /*
3880          * Return non-zero, if state transition has already happened.
3881          */
3882         return 1;
3883 }
3884
3885 /*
3886  * This is called from xfs_force_shutdown, when we're forcibly
3887  * shutting down the filesystem, typically because of an IO error.
3888  * Our main objectives here are to make sure that:
3889  *      a. if !logerror, flush the logs to disk. Anything modified
3890  *         after this is ignored.
3891  *      b. the filesystem gets marked 'SHUTDOWN' for all interested
3892  *         parties to find out, 'atomically'.
3893  *      c. those who're sleeping on log reservations, pinned objects and
3894  *          other resources get woken up, and be told the bad news.
3895  *      d. nothing new gets queued up after (b) and (c) are done.
3896  *
3897  * Note: for the !logerror case we need to flush the regions held in memory out
3898  * to disk first. This needs to be done before the log is marked as shutdown,
3899  * otherwise the iclog writes will fail.
3900  */
3901 int
3902 xfs_log_force_umount(
3903         struct xfs_mount        *mp,
3904         int                     logerror)
3905 {
3906         struct xlog     *log;
3907         int             retval;
3908
3909         log = mp->m_log;
3910
3911         /*
3912          * If this happens during log recovery, don't worry about
3913          * locking; the log isn't open for business yet.
3914          */
3915         if (!log ||
3916             log->l_flags & XLOG_ACTIVE_RECOVERY) {
3917                 mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3918                 if (mp->m_sb_bp)
3919                         mp->m_sb_bp->b_flags |= XBF_DONE;
3920                 return 0;
3921         }
3922
3923         /*
3924          * Somebody could've already done the hard work for us.
3925          * No need to get locks for this.
3926          */
3927         if (logerror && log->l_iclog->ic_state & XLOG_STATE_IOERROR) {
3928                 ASSERT(XLOG_FORCED_SHUTDOWN(log));
3929                 return 1;
3930         }
3931
3932         /*
3933          * Flush all the completed transactions to disk before marking the log
3934          * being shut down. We need to do it in this order to ensure that
3935          * completed operations are safely on disk before we shut down, and that
3936          * we don't have to issue any buffer IO after the shutdown flags are set
3937          * to guarantee this.
3938          */
3939         if (!logerror)
3940                 xfs_log_force(mp, XFS_LOG_SYNC);
3941
3942         /*
3943          * mark the filesystem and the as in a shutdown state and wake
3944          * everybody up to tell them the bad news.
3945          */
3946         spin_lock(&log->l_icloglock);
3947         mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3948         if (mp->m_sb_bp)
3949                 mp->m_sb_bp->b_flags |= XBF_DONE;
3950
3951         /*
3952          * Mark the log and the iclogs with IO error flags to prevent any
3953          * further log IO from being issued or completed.
3954          */
3955         log->l_flags |= XLOG_IO_ERROR;
3956         retval = xlog_state_ioerror(log);
3957         spin_unlock(&log->l_icloglock);
3958
3959         /*
3960          * We don't want anybody waiting for log reservations after this. That
3961          * means we have to wake up everybody queued up on reserveq as well as
3962          * writeq.  In addition, we make sure in xlog_{re}grant_log_space that
3963          * we don't enqueue anything once the SHUTDOWN flag is set, and this
3964          * action is protected by the grant locks.
3965          */
3966         xlog_grant_head_wake_all(&log->l_reserve_head);
3967         xlog_grant_head_wake_all(&log->l_write_head);
3968
3969         /*
3970          * Wake up everybody waiting on xfs_log_force. Wake the CIL push first
3971          * as if the log writes were completed. The abort handling in the log
3972          * item committed callback functions will do this again under lock to
3973          * avoid races.
3974          */
3975         wake_up_all(&log->l_cilp->xc_commit_wait);
3976         xlog_state_do_callback(log, XFS_LI_ABORTED, NULL);
3977
3978 #ifdef XFSERRORDEBUG
3979         {
3980                 xlog_in_core_t  *iclog;
3981
3982                 spin_lock(&log->l_icloglock);
3983                 iclog = log->l_iclog;
3984                 do {
3985                         ASSERT(iclog->ic_callback == 0);
3986                         iclog = iclog->ic_next;
3987                 } while (iclog != log->l_iclog);
3988                 spin_unlock(&log->l_icloglock);
3989         }
3990 #endif
3991         /* return non-zero if log IOERROR transition had already happened */
3992         return retval;
3993 }
3994
3995 STATIC int
3996 xlog_iclogs_empty(
3997         struct xlog     *log)
3998 {
3999         xlog_in_core_t  *iclog;
4000
4001         iclog = log->l_iclog;
4002         do {
4003                 /* endianness does not matter here, zero is zero in
4004                  * any language.
4005                  */
4006                 if (iclog->ic_header.h_num_logops)
4007                         return 0;
4008                 iclog = iclog->ic_next;
4009         } while (iclog != log->l_iclog);
4010         return 1;
4011 }
4012
4013 /*
4014  * Verify that an LSN stamped into a piece of metadata is valid. This is
4015  * intended for use in read verifiers on v5 superblocks.
4016  */
4017 bool
4018 xfs_log_check_lsn(
4019         struct xfs_mount        *mp,
4020         xfs_lsn_t               lsn)
4021 {
4022         struct xlog             *log = mp->m_log;
4023         bool                    valid;
4024
4025         /*
4026          * norecovery mode skips mount-time log processing and unconditionally
4027          * resets the in-core LSN. We can't validate in this mode, but
4028          * modifications are not allowed anyways so just return true.
4029          */
4030         if (mp->m_flags & XFS_MOUNT_NORECOVERY)
4031                 return true;
4032
4033         /*
4034          * Some metadata LSNs are initialized to NULL (e.g., the agfl). This is
4035          * handled by recovery and thus safe to ignore here.
4036          */
4037         if (lsn == NULLCOMMITLSN)
4038                 return true;
4039
4040         valid = xlog_valid_lsn(mp->m_log, lsn);
4041
4042         /* warn the user about what's gone wrong before verifier failure */
4043         if (!valid) {
4044                 spin_lock(&log->l_icloglock);
4045                 xfs_warn(mp,
4046 "Corruption warning: Metadata has LSN (%d:%d) ahead of current LSN (%d:%d). "
4047 "Please unmount and run xfs_repair (>= v4.3) to resolve.",
4048                          CYCLE_LSN(lsn), BLOCK_LSN(lsn),
4049                          log->l_curr_cycle, log->l_curr_block);
4050                 spin_unlock(&log->l_icloglock);
4051         }
4052
4053         return valid;
4054 }
4055
4056 bool
4057 xfs_log_in_recovery(
4058         struct xfs_mount        *mp)
4059 {
4060         struct xlog             *log = mp->m_log;
4061
4062         return log->l_flags & XLOG_ACTIVE_RECOVERY;
4063 }