linux/fs/xfs/xfs_log.c
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   1/*
   2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   3 * All Rights Reserved.
   4 *
   5 * This program is free software; you can redistribute it and/or
   6 * modify it under the terms of the GNU General Public License as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it would be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write the Free Software Foundation,
  16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17 */
  18#include "xfs.h"
  19#include "xfs_fs.h"
  20#include "xfs_types.h"
  21#include "xfs_log.h"
  22#include "xfs_trans.h"
  23#include "xfs_sb.h"
  24#include "xfs_ag.h"
  25#include "xfs_mount.h"
  26#include "xfs_error.h"
  27#include "xfs_log_priv.h"
  28#include "xfs_buf_item.h"
  29#include "xfs_bmap_btree.h"
  30#include "xfs_alloc_btree.h"
  31#include "xfs_ialloc_btree.h"
  32#include "xfs_log_recover.h"
  33#include "xfs_trans_priv.h"
  34#include "xfs_dinode.h"
  35#include "xfs_inode.h"
  36#include "xfs_trace.h"
  37#include "xfs_fsops.h"
  38#include "xfs_cksum.h"
  39
  40kmem_zone_t     *xfs_log_ticket_zone;
  41
  42/* Local miscellaneous function prototypes */
  43STATIC int
  44xlog_commit_record(
  45        struct xlog             *log,
  46        struct xlog_ticket      *ticket,
  47        struct xlog_in_core     **iclog,
  48        xfs_lsn_t               *commitlsnp);
  49
  50STATIC struct xlog *
  51xlog_alloc_log(
  52        struct xfs_mount        *mp,
  53        struct xfs_buftarg      *log_target,
  54        xfs_daddr_t             blk_offset,
  55        int                     num_bblks);
  56STATIC int
  57xlog_space_left(
  58        struct xlog             *log,
  59        atomic64_t              *head);
  60STATIC int
  61xlog_sync(
  62        struct xlog             *log,
  63        struct xlog_in_core     *iclog);
  64STATIC void
  65xlog_dealloc_log(
  66        struct xlog             *log);
  67
  68/* local state machine functions */
  69STATIC void xlog_state_done_syncing(xlog_in_core_t *iclog, int);
  70STATIC void
  71xlog_state_do_callback(
  72        struct xlog             *log,
  73        int                     aborted,
  74        struct xlog_in_core     *iclog);
  75STATIC int
  76xlog_state_get_iclog_space(
  77        struct xlog             *log,
  78        int                     len,
  79        struct xlog_in_core     **iclog,
  80        struct xlog_ticket      *ticket,
  81        int                     *continued_write,
  82        int                     *logoffsetp);
  83STATIC int
  84xlog_state_release_iclog(
  85        struct xlog             *log,
  86        struct xlog_in_core     *iclog);
  87STATIC void
  88xlog_state_switch_iclogs(
  89        struct xlog             *log,
  90        struct xlog_in_core     *iclog,
  91        int                     eventual_size);
  92STATIC void
  93xlog_state_want_sync(
  94        struct xlog             *log,
  95        struct xlog_in_core     *iclog);
  96
  97STATIC void
  98xlog_grant_push_ail(
  99        struct xlog             *log,
 100        int                     need_bytes);
 101STATIC void
 102xlog_regrant_reserve_log_space(
 103        struct xlog             *log,
 104        struct xlog_ticket      *ticket);
 105STATIC void
 106xlog_ungrant_log_space(
 107        struct xlog             *log,
 108        struct xlog_ticket      *ticket);
 109
 110#if defined(DEBUG)
 111STATIC void
 112xlog_verify_dest_ptr(
 113        struct xlog             *log,
 114        char                    *ptr);
 115STATIC void
 116xlog_verify_grant_tail(
 117        struct xlog *log);
 118STATIC void
 119xlog_verify_iclog(
 120        struct xlog             *log,
 121        struct xlog_in_core     *iclog,
 122        int                     count,
 123        boolean_t               syncing);
 124STATIC void
 125xlog_verify_tail_lsn(
 126        struct xlog             *log,
 127        struct xlog_in_core     *iclog,
 128        xfs_lsn_t               tail_lsn);
 129#else
 130#define xlog_verify_dest_ptr(a,b)
 131#define xlog_verify_grant_tail(a)
 132#define xlog_verify_iclog(a,b,c,d)
 133#define xlog_verify_tail_lsn(a,b,c)
 134#endif
 135
 136STATIC int
 137xlog_iclogs_empty(
 138        struct xlog             *log);
 139
 140static void
 141xlog_grant_sub_space(
 142        struct xlog             *log,
 143        atomic64_t              *head,
 144        int                     bytes)
 145{
 146        int64_t head_val = atomic64_read(head);
 147        int64_t new, old;
 148
 149        do {
 150                int     cycle, space;
 151
 152                xlog_crack_grant_head_val(head_val, &cycle, &space);
 153
 154                space -= bytes;
 155                if (space < 0) {
 156                        space += log->l_logsize;
 157                        cycle--;
 158                }
 159
 160                old = head_val;
 161                new = xlog_assign_grant_head_val(cycle, space);
 162                head_val = atomic64_cmpxchg(head, old, new);
 163        } while (head_val != old);
 164}
 165
 166static void
 167xlog_grant_add_space(
 168        struct xlog             *log,
 169        atomic64_t              *head,
 170        int                     bytes)
 171{
 172        int64_t head_val = atomic64_read(head);
 173        int64_t new, old;
 174
 175        do {
 176                int             tmp;
 177                int             cycle, space;
 178
 179                xlog_crack_grant_head_val(head_val, &cycle, &space);
 180
 181                tmp = log->l_logsize - space;
 182                if (tmp > bytes)
 183                        space += bytes;
 184                else {
 185                        space = bytes - tmp;
 186                        cycle++;
 187                }
 188
 189                old = head_val;
 190                new = xlog_assign_grant_head_val(cycle, space);
 191                head_val = atomic64_cmpxchg(head, old, new);
 192        } while (head_val != old);
 193}
 194
 195STATIC void
 196xlog_grant_head_init(
 197        struct xlog_grant_head  *head)
 198{
 199        xlog_assign_grant_head(&head->grant, 1, 0);
 200        INIT_LIST_HEAD(&head->waiters);
 201        spin_lock_init(&head->lock);
 202}
 203
 204STATIC void
 205xlog_grant_head_wake_all(
 206        struct xlog_grant_head  *head)
 207{
 208        struct xlog_ticket      *tic;
 209
 210        spin_lock(&head->lock);
 211        list_for_each_entry(tic, &head->waiters, t_queue)
 212                wake_up_process(tic->t_task);
 213        spin_unlock(&head->lock);
 214}
 215
 216static inline int
 217xlog_ticket_reservation(
 218        struct xlog             *log,
 219        struct xlog_grant_head  *head,
 220        struct xlog_ticket      *tic)
 221{
 222        if (head == &log->l_write_head) {
 223                ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
 224                return tic->t_unit_res;
 225        } else {
 226                if (tic->t_flags & XLOG_TIC_PERM_RESERV)
 227                        return tic->t_unit_res * tic->t_cnt;
 228                else
 229                        return tic->t_unit_res;
 230        }
 231}
 232
 233STATIC bool
 234xlog_grant_head_wake(
 235        struct xlog             *log,
 236        struct xlog_grant_head  *head,
 237        int                     *free_bytes)
 238{
 239        struct xlog_ticket      *tic;
 240        int                     need_bytes;
 241
 242        list_for_each_entry(tic, &head->waiters, t_queue) {
 243                need_bytes = xlog_ticket_reservation(log, head, tic);
 244                if (*free_bytes < need_bytes)
 245                        return false;
 246
 247                *free_bytes -= need_bytes;
 248                trace_xfs_log_grant_wake_up(log, tic);
 249                wake_up_process(tic->t_task);
 250        }
 251
 252        return true;
 253}
 254
 255STATIC int
 256xlog_grant_head_wait(
 257        struct xlog             *log,
 258        struct xlog_grant_head  *head,
 259        struct xlog_ticket      *tic,
 260        int                     need_bytes)
 261{
 262        list_add_tail(&tic->t_queue, &head->waiters);
 263
 264        do {
 265                if (XLOG_FORCED_SHUTDOWN(log))
 266                        goto shutdown;
 267                xlog_grant_push_ail(log, need_bytes);
 268
 269                __set_current_state(TASK_UNINTERRUPTIBLE);
 270                spin_unlock(&head->lock);
 271
 272                XFS_STATS_INC(xs_sleep_logspace);
 273
 274                trace_xfs_log_grant_sleep(log, tic);
 275                schedule();
 276                trace_xfs_log_grant_wake(log, tic);
 277
 278                spin_lock(&head->lock);
 279                if (XLOG_FORCED_SHUTDOWN(log))
 280                        goto shutdown;
 281        } while (xlog_space_left(log, &head->grant) < need_bytes);
 282
 283        list_del_init(&tic->t_queue);
 284        return 0;
 285shutdown:
 286        list_del_init(&tic->t_queue);
 287        return XFS_ERROR(EIO);
 288}
 289
 290/*
 291 * Atomically get the log space required for a log ticket.
 292 *
 293 * Once a ticket gets put onto head->waiters, it will only return after the
 294 * needed reservation is satisfied.
 295 *
 296 * This function is structured so that it has a lock free fast path. This is
 297 * necessary because every new transaction reservation will come through this
 298 * path. Hence any lock will be globally hot if we take it unconditionally on
 299 * every pass.
 300 *
 301 * As tickets are only ever moved on and off head->waiters under head->lock, we
 302 * only need to take that lock if we are going to add the ticket to the queue
 303 * and sleep. We can avoid taking the lock if the ticket was never added to
 304 * head->waiters because the t_queue list head will be empty and we hold the
 305 * only reference to it so it can safely be checked unlocked.
 306 */
 307STATIC int
 308xlog_grant_head_check(
 309        struct xlog             *log,
 310        struct xlog_grant_head  *head,
 311        struct xlog_ticket      *tic,
 312        int                     *need_bytes)
 313{
 314        int                     free_bytes;
 315        int                     error = 0;
 316
 317        ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
 318
 319        /*
 320         * If there are other waiters on the queue then give them a chance at
 321         * logspace before us.  Wake up the first waiters, if we do not wake
 322         * up all the waiters then go to sleep waiting for more free space,
 323         * otherwise try to get some space for this transaction.
 324         */
 325        *need_bytes = xlog_ticket_reservation(log, head, tic);
 326        free_bytes = xlog_space_left(log, &head->grant);
 327        if (!list_empty_careful(&head->waiters)) {
 328                spin_lock(&head->lock);
 329                if (!xlog_grant_head_wake(log, head, &free_bytes) ||
 330                    free_bytes < *need_bytes) {
 331                        error = xlog_grant_head_wait(log, head, tic,
 332                                                     *need_bytes);
 333                }
 334                spin_unlock(&head->lock);
 335        } else if (free_bytes < *need_bytes) {
 336                spin_lock(&head->lock);
 337                error = xlog_grant_head_wait(log, head, tic, *need_bytes);
 338                spin_unlock(&head->lock);
 339        }
 340
 341        return error;
 342}
 343
 344static void
 345xlog_tic_reset_res(xlog_ticket_t *tic)
 346{
 347        tic->t_res_num = 0;
 348        tic->t_res_arr_sum = 0;
 349        tic->t_res_num_ophdrs = 0;
 350}
 351
 352static void
 353xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type)
 354{
 355        if (tic->t_res_num == XLOG_TIC_LEN_MAX) {
 356                /* add to overflow and start again */
 357                tic->t_res_o_flow += tic->t_res_arr_sum;
 358                tic->t_res_num = 0;
 359                tic->t_res_arr_sum = 0;
 360        }
 361
 362        tic->t_res_arr[tic->t_res_num].r_len = len;
 363        tic->t_res_arr[tic->t_res_num].r_type = type;
 364        tic->t_res_arr_sum += len;
 365        tic->t_res_num++;
 366}
 367
 368/*
 369 * Replenish the byte reservation required by moving the grant write head.
 370 */
 371int
 372xfs_log_regrant(
 373        struct xfs_mount        *mp,
 374        struct xlog_ticket      *tic)
 375{
 376        struct xlog             *log = mp->m_log;
 377        int                     need_bytes;
 378        int                     error = 0;
 379
 380        if (XLOG_FORCED_SHUTDOWN(log))
 381                return XFS_ERROR(EIO);
 382
 383        XFS_STATS_INC(xs_try_logspace);
 384
 385        /*
 386         * This is a new transaction on the ticket, so we need to change the
 387         * transaction ID so that the next transaction has a different TID in
 388         * the log. Just add one to the existing tid so that we can see chains
 389         * of rolling transactions in the log easily.
 390         */
 391        tic->t_tid++;
 392
 393        xlog_grant_push_ail(log, tic->t_unit_res);
 394
 395        tic->t_curr_res = tic->t_unit_res;
 396        xlog_tic_reset_res(tic);
 397
 398        if (tic->t_cnt > 0)
 399                return 0;
 400
 401        trace_xfs_log_regrant(log, tic);
 402
 403        error = xlog_grant_head_check(log, &log->l_write_head, tic,
 404                                      &need_bytes);
 405        if (error)
 406                goto out_error;
 407
 408        xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
 409        trace_xfs_log_regrant_exit(log, tic);
 410        xlog_verify_grant_tail(log);
 411        return 0;
 412
 413out_error:
 414        /*
 415         * If we are failing, make sure the ticket doesn't have any current
 416         * reservations.  We don't want to add this back when the ticket/
 417         * transaction gets cancelled.
 418         */
 419        tic->t_curr_res = 0;
 420        tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
 421        return error;
 422}
 423
 424/*
 425 * Reserve log space and return a ticket corresponding the reservation.
 426 *
 427 * Each reservation is going to reserve extra space for a log record header.
 428 * When writes happen to the on-disk log, we don't subtract the length of the
 429 * log record header from any reservation.  By wasting space in each
 430 * reservation, we prevent over allocation problems.
 431 */
 432int
 433xfs_log_reserve(
 434        struct xfs_mount        *mp,
 435        int                     unit_bytes,
 436        int                     cnt,
 437        struct xlog_ticket      **ticp,
 438        __uint8_t               client,
 439        bool                    permanent,
 440        uint                    t_type)
 441{
 442        struct xlog             *log = mp->m_log;
 443        struct xlog_ticket      *tic;
 444        int                     need_bytes;
 445        int                     error = 0;
 446
 447        ASSERT(client == XFS_TRANSACTION || client == XFS_LOG);
 448
 449        if (XLOG_FORCED_SHUTDOWN(log))
 450                return XFS_ERROR(EIO);
 451
 452        XFS_STATS_INC(xs_try_logspace);
 453
 454        ASSERT(*ticp == NULL);
 455        tic = xlog_ticket_alloc(log, unit_bytes, cnt, client, permanent,
 456                                KM_SLEEP | KM_MAYFAIL);
 457        if (!tic)
 458                return XFS_ERROR(ENOMEM);
 459
 460        tic->t_trans_type = t_type;
 461        *ticp = tic;
 462
 463        xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt
 464                                            : tic->t_unit_res);
 465
 466        trace_xfs_log_reserve(log, tic);
 467
 468        error = xlog_grant_head_check(log, &log->l_reserve_head, tic,
 469                                      &need_bytes);
 470        if (error)
 471                goto out_error;
 472
 473        xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes);
 474        xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
 475        trace_xfs_log_reserve_exit(log, tic);
 476        xlog_verify_grant_tail(log);
 477        return 0;
 478
 479out_error:
 480        /*
 481         * If we are failing, make sure the ticket doesn't have any current
 482         * reservations.  We don't want to add this back when the ticket/
 483         * transaction gets cancelled.
 484         */
 485        tic->t_curr_res = 0;
 486        tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
 487        return error;
 488}
 489
 490
 491/*
 492 * NOTES:
 493 *
 494 *      1. currblock field gets updated at startup and after in-core logs
 495 *              marked as with WANT_SYNC.
 496 */
 497
 498/*
 499 * This routine is called when a user of a log manager ticket is done with
 500 * the reservation.  If the ticket was ever used, then a commit record for
 501 * the associated transaction is written out as a log operation header with
 502 * no data.  The flag XLOG_TIC_INITED is set when the first write occurs with
 503 * a given ticket.  If the ticket was one with a permanent reservation, then
 504 * a few operations are done differently.  Permanent reservation tickets by
 505 * default don't release the reservation.  They just commit the current
 506 * transaction with the belief that the reservation is still needed.  A flag
 507 * must be passed in before permanent reservations are actually released.
 508 * When these type of tickets are not released, they need to be set into
 509 * the inited state again.  By doing this, a start record will be written
 510 * out when the next write occurs.
 511 */
 512xfs_lsn_t
 513xfs_log_done(
 514        struct xfs_mount        *mp,
 515        struct xlog_ticket      *ticket,
 516        struct xlog_in_core     **iclog,
 517        uint                    flags)
 518{
 519        struct xlog             *log = mp->m_log;
 520        xfs_lsn_t               lsn = 0;
 521
 522        if (XLOG_FORCED_SHUTDOWN(log) ||
 523            /*
 524             * If nothing was ever written, don't write out commit record.
 525             * If we get an error, just continue and give back the log ticket.
 526             */
 527            (((ticket->t_flags & XLOG_TIC_INITED) == 0) &&
 528             (xlog_commit_record(log, ticket, iclog, &lsn)))) {
 529                lsn = (xfs_lsn_t) -1;
 530                if (ticket->t_flags & XLOG_TIC_PERM_RESERV) {
 531                        flags |= XFS_LOG_REL_PERM_RESERV;
 532                }
 533        }
 534
 535
 536        if ((ticket->t_flags & XLOG_TIC_PERM_RESERV) == 0 ||
 537            (flags & XFS_LOG_REL_PERM_RESERV)) {
 538                trace_xfs_log_done_nonperm(log, ticket);
 539
 540                /*
 541                 * Release ticket if not permanent reservation or a specific
 542                 * request has been made to release a permanent reservation.
 543                 */
 544                xlog_ungrant_log_space(log, ticket);
 545                xfs_log_ticket_put(ticket);
 546        } else {
 547                trace_xfs_log_done_perm(log, ticket);
 548
 549                xlog_regrant_reserve_log_space(log, ticket);
 550                /* If this ticket was a permanent reservation and we aren't
 551                 * trying to release it, reset the inited flags; so next time
 552                 * we write, a start record will be written out.
 553                 */
 554                ticket->t_flags |= XLOG_TIC_INITED;
 555        }
 556
 557        return lsn;
 558}
 559
 560/*
 561 * Attaches a new iclog I/O completion callback routine during
 562 * transaction commit.  If the log is in error state, a non-zero
 563 * return code is handed back and the caller is responsible for
 564 * executing the callback at an appropriate time.
 565 */
 566int
 567xfs_log_notify(
 568        struct xfs_mount        *mp,
 569        struct xlog_in_core     *iclog,
 570        xfs_log_callback_t      *cb)
 571{
 572        int     abortflg;
 573
 574        spin_lock(&iclog->ic_callback_lock);
 575        abortflg = (iclog->ic_state & XLOG_STATE_IOERROR);
 576        if (!abortflg) {
 577                ASSERT_ALWAYS((iclog->ic_state == XLOG_STATE_ACTIVE) ||
 578                              (iclog->ic_state == XLOG_STATE_WANT_SYNC));
 579                cb->cb_next = NULL;
 580                *(iclog->ic_callback_tail) = cb;
 581                iclog->ic_callback_tail = &(cb->cb_next);
 582        }
 583        spin_unlock(&iclog->ic_callback_lock);
 584        return abortflg;
 585}
 586
 587int
 588xfs_log_release_iclog(
 589        struct xfs_mount        *mp,
 590        struct xlog_in_core     *iclog)
 591{
 592        if (xlog_state_release_iclog(mp->m_log, iclog)) {
 593                xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
 594                return EIO;
 595        }
 596
 597        return 0;
 598}
 599
 600/*
 601 * Mount a log filesystem
 602 *
 603 * mp           - ubiquitous xfs mount point structure
 604 * log_target   - buftarg of on-disk log device
 605 * blk_offset   - Start block # where block size is 512 bytes (BBSIZE)
 606 * num_bblocks  - Number of BBSIZE blocks in on-disk log
 607 *
 608 * Return error or zero.
 609 */
 610int
 611xfs_log_mount(
 612        xfs_mount_t     *mp,
 613        xfs_buftarg_t   *log_target,
 614        xfs_daddr_t     blk_offset,
 615        int             num_bblks)
 616{
 617        int             error;
 618
 619        if (!(mp->m_flags & XFS_MOUNT_NORECOVERY))
 620                xfs_notice(mp, "Mounting Filesystem");
 621        else {
 622                xfs_notice(mp,
 623"Mounting filesystem in no-recovery mode.  Filesystem will be inconsistent.");
 624                ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 625        }
 626
 627        mp->m_log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
 628        if (IS_ERR(mp->m_log)) {
 629                error = -PTR_ERR(mp->m_log);
 630                goto out;
 631        }
 632
 633        /*
 634         * Initialize the AIL now we have a log.
 635         */
 636        error = xfs_trans_ail_init(mp);
 637        if (error) {
 638                xfs_warn(mp, "AIL initialisation failed: error %d", error);
 639                goto out_free_log;
 640        }
 641        mp->m_log->l_ailp = mp->m_ail;
 642
 643        /*
 644         * skip log recovery on a norecovery mount.  pretend it all
 645         * just worked.
 646         */
 647        if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
 648                int     readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
 649
 650                if (readonly)
 651                        mp->m_flags &= ~XFS_MOUNT_RDONLY;
 652
 653                error = xlog_recover(mp->m_log);
 654
 655                if (readonly)
 656                        mp->m_flags |= XFS_MOUNT_RDONLY;
 657                if (error) {
 658                        xfs_warn(mp, "log mount/recovery failed: error %d",
 659                                error);
 660                        goto out_destroy_ail;
 661                }
 662        }
 663
 664        /* Normal transactions can now occur */
 665        mp->m_log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
 666
 667        /*
 668         * Now the log has been fully initialised and we know were our
 669         * space grant counters are, we can initialise the permanent ticket
 670         * needed for delayed logging to work.
 671         */
 672        xlog_cil_init_post_recovery(mp->m_log);
 673
 674        return 0;
 675
 676out_destroy_ail:
 677        xfs_trans_ail_destroy(mp);
 678out_free_log:
 679        xlog_dealloc_log(mp->m_log);
 680out:
 681        return error;
 682}
 683
 684/*
 685 * Finish the recovery of the file system.  This is separate from the
 686 * xfs_log_mount() call, because it depends on the code in xfs_mountfs() to read
 687 * in the root and real-time bitmap inodes between calling xfs_log_mount() and
 688 * here.
 689 *
 690 * If we finish recovery successfully, start the background log work. If we are
 691 * not doing recovery, then we have a RO filesystem and we don't need to start
 692 * it.
 693 */
 694int
 695xfs_log_mount_finish(xfs_mount_t *mp)
 696{
 697        int     error = 0;
 698
 699        if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
 700                error = xlog_recover_finish(mp->m_log);
 701                if (!error)
 702                        xfs_log_work_queue(mp);
 703        } else {
 704                ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 705        }
 706
 707
 708        return error;
 709}
 710
 711/*
 712 * Final log writes as part of unmount.
 713 *
 714 * Mark the filesystem clean as unmount happens.  Note that during relocation
 715 * this routine needs to be executed as part of source-bag while the
 716 * deallocation must not be done until source-end.
 717 */
 718
 719/*
 720 * Unmount record used to have a string "Unmount filesystem--" in the
 721 * data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
 722 * We just write the magic number now since that particular field isn't
 723 * currently architecture converted and "nUmount" is a bit foo.
 724 * As far as I know, there weren't any dependencies on the old behaviour.
 725 */
 726
 727int
 728xfs_log_unmount_write(xfs_mount_t *mp)
 729{
 730        struct xlog      *log = mp->m_log;
 731        xlog_in_core_t   *iclog;
 732#ifdef DEBUG
 733        xlog_in_core_t   *first_iclog;
 734#endif
 735        xlog_ticket_t   *tic = NULL;
 736        xfs_lsn_t        lsn;
 737        int              error;
 738
 739        /*
 740         * Don't write out unmount record on read-only mounts.
 741         * Or, if we are doing a forced umount (typically because of IO errors).
 742         */
 743        if (mp->m_flags & XFS_MOUNT_RDONLY)
 744                return 0;
 745
 746        error = _xfs_log_force(mp, XFS_LOG_SYNC, NULL);
 747        ASSERT(error || !(XLOG_FORCED_SHUTDOWN(log)));
 748
 749#ifdef DEBUG
 750        first_iclog = iclog = log->l_iclog;
 751        do {
 752                if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
 753                        ASSERT(iclog->ic_state & XLOG_STATE_ACTIVE);
 754                        ASSERT(iclog->ic_offset == 0);
 755                }
 756                iclog = iclog->ic_next;
 757        } while (iclog != first_iclog);
 758#endif
 759        if (! (XLOG_FORCED_SHUTDOWN(log))) {
 760                error = xfs_log_reserve(mp, 600, 1, &tic,
 761                                        XFS_LOG, 0, XLOG_UNMOUNT_REC_TYPE);
 762                if (!error) {
 763                        /* the data section must be 32 bit size aligned */
 764                        struct {
 765                            __uint16_t magic;
 766                            __uint16_t pad1;
 767                            __uint32_t pad2; /* may as well make it 64 bits */
 768                        } magic = {
 769                                .magic = XLOG_UNMOUNT_TYPE,
 770                        };
 771                        struct xfs_log_iovec reg = {
 772                                .i_addr = &magic,
 773                                .i_len = sizeof(magic),
 774                                .i_type = XLOG_REG_TYPE_UNMOUNT,
 775                        };
 776                        struct xfs_log_vec vec = {
 777                                .lv_niovecs = 1,
 778                                .lv_iovecp = &reg,
 779                        };
 780
 781                        /* remove inited flag, and account for space used */
 782                        tic->t_flags = 0;
 783                        tic->t_curr_res -= sizeof(magic);
 784                        error = xlog_write(log, &vec, tic, &lsn,
 785                                           NULL, XLOG_UNMOUNT_TRANS);
 786                        /*
 787                         * At this point, we're umounting anyway,
 788                         * so there's no point in transitioning log state
 789                         * to IOERROR. Just continue...
 790                         */
 791                }
 792
 793                if (error)
 794                        xfs_alert(mp, "%s: unmount record failed", __func__);
 795
 796
 797                spin_lock(&log->l_icloglock);
 798                iclog = log->l_iclog;
 799                atomic_inc(&iclog->ic_refcnt);
 800                xlog_state_want_sync(log, iclog);
 801                spin_unlock(&log->l_icloglock);
 802                error = xlog_state_release_iclog(log, iclog);
 803
 804                spin_lock(&log->l_icloglock);
 805                if (!(iclog->ic_state == XLOG_STATE_ACTIVE ||
 806                      iclog->ic_state == XLOG_STATE_DIRTY)) {
 807                        if (!XLOG_FORCED_SHUTDOWN(log)) {
 808                                xlog_wait(&iclog->ic_force_wait,
 809                                                        &log->l_icloglock);
 810                        } else {
 811                                spin_unlock(&log->l_icloglock);
 812                        }
 813                } else {
 814                        spin_unlock(&log->l_icloglock);
 815                }
 816                if (tic) {
 817                        trace_xfs_log_umount_write(log, tic);
 818                        xlog_ungrant_log_space(log, tic);
 819                        xfs_log_ticket_put(tic);
 820                }
 821        } else {
 822                /*
 823                 * We're already in forced_shutdown mode, couldn't
 824                 * even attempt to write out the unmount transaction.
 825                 *
 826                 * Go through the motions of sync'ing and releasing
 827                 * the iclog, even though no I/O will actually happen,
 828                 * we need to wait for other log I/Os that may already
 829                 * be in progress.  Do this as a separate section of
 830                 * code so we'll know if we ever get stuck here that
 831                 * we're in this odd situation of trying to unmount
 832                 * a file system that went into forced_shutdown as
 833                 * the result of an unmount..
 834                 */
 835                spin_lock(&log->l_icloglock);
 836                iclog = log->l_iclog;
 837                atomic_inc(&iclog->ic_refcnt);
 838
 839                xlog_state_want_sync(log, iclog);
 840                spin_unlock(&log->l_icloglock);
 841                error =  xlog_state_release_iclog(log, iclog);
 842
 843                spin_lock(&log->l_icloglock);
 844
 845                if ( ! (   iclog->ic_state == XLOG_STATE_ACTIVE
 846                        || iclog->ic_state == XLOG_STATE_DIRTY
 847                        || iclog->ic_state == XLOG_STATE_IOERROR) ) {
 848
 849                                xlog_wait(&iclog->ic_force_wait,
 850                                                        &log->l_icloglock);
 851                } else {
 852                        spin_unlock(&log->l_icloglock);
 853                }
 854        }
 855
 856        return error;
 857}       /* xfs_log_unmount_write */
 858
 859/*
 860 * Empty the log for unmount/freeze.
 861 *
 862 * To do this, we first need to shut down the background log work so it is not
 863 * trying to cover the log as we clean up. We then need to unpin all objects in
 864 * the log so we can then flush them out. Once they have completed their IO and
 865 * run the callbacks removing themselves from the AIL, we can write the unmount
 866 * record.
 867 */
 868void
 869xfs_log_quiesce(
 870        struct xfs_mount        *mp)
 871{
 872        cancel_delayed_work_sync(&mp->m_log->l_work);
 873        xfs_log_force(mp, XFS_LOG_SYNC);
 874
 875        /*
 876         * The superblock buffer is uncached and while xfs_ail_push_all_sync()
 877         * will push it, xfs_wait_buftarg() will not wait for it. Further,
 878         * xfs_buf_iowait() cannot be used because it was pushed with the
 879         * XBF_ASYNC flag set, so we need to use a lock/unlock pair to wait for
 880         * the IO to complete.
 881         */
 882        xfs_ail_push_all_sync(mp->m_ail);
 883        xfs_wait_buftarg(mp->m_ddev_targp);
 884        xfs_buf_lock(mp->m_sb_bp);
 885        xfs_buf_unlock(mp->m_sb_bp);
 886
 887        xfs_log_unmount_write(mp);
 888}
 889
 890/*
 891 * Shut down and release the AIL and Log.
 892 *
 893 * During unmount, we need to ensure we flush all the dirty metadata objects
 894 * from the AIL so that the log is empty before we write the unmount record to
 895 * the log. Once this is done, we can tear down the AIL and the log.
 896 */
 897void
 898xfs_log_unmount(
 899        struct xfs_mount        *mp)
 900{
 901        xfs_log_quiesce(mp);
 902
 903        xfs_trans_ail_destroy(mp);
 904        xlog_dealloc_log(mp->m_log);
 905}
 906
 907void
 908xfs_log_item_init(
 909        struct xfs_mount        *mp,
 910        struct xfs_log_item     *item,
 911        int                     type,
 912        const struct xfs_item_ops *ops)
 913{
 914        item->li_mountp = mp;
 915        item->li_ailp = mp->m_ail;
 916        item->li_type = type;
 917        item->li_ops = ops;
 918        item->li_lv = NULL;
 919
 920        INIT_LIST_HEAD(&item->li_ail);
 921        INIT_LIST_HEAD(&item->li_cil);
 922}
 923
 924/*
 925 * Wake up processes waiting for log space after we have moved the log tail.
 926 */
 927void
 928xfs_log_space_wake(
 929        struct xfs_mount        *mp)
 930{
 931        struct xlog             *log = mp->m_log;
 932        int                     free_bytes;
 933
 934        if (XLOG_FORCED_SHUTDOWN(log))
 935                return;
 936
 937        if (!list_empty_careful(&log->l_write_head.waiters)) {
 938                ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
 939
 940                spin_lock(&log->l_write_head.lock);
 941                free_bytes = xlog_space_left(log, &log->l_write_head.grant);
 942                xlog_grant_head_wake(log, &log->l_write_head, &free_bytes);
 943                spin_unlock(&log->l_write_head.lock);
 944        }
 945
 946        if (!list_empty_careful(&log->l_reserve_head.waiters)) {
 947                ASSERT(!(log->l_flags & XLOG_ACTIVE_RECOVERY));
 948
 949                spin_lock(&log->l_reserve_head.lock);
 950                free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
 951                xlog_grant_head_wake(log, &log->l_reserve_head, &free_bytes);
 952                spin_unlock(&log->l_reserve_head.lock);
 953        }
 954}
 955
 956/*
 957 * Determine if we have a transaction that has gone to disk
 958 * that needs to be covered. To begin the transition to the idle state
 959 * firstly the log needs to be idle (no AIL and nothing in the iclogs).
 960 * If we are then in a state where covering is needed, the caller is informed
 961 * that dummy transactions are required to move the log into the idle state.
 962 *
 963 * Because this is called as part of the sync process, we should also indicate
 964 * that dummy transactions should be issued in anything but the covered or
 965 * idle states. This ensures that the log tail is accurately reflected in
 966 * the log at the end of the sync, hence if a crash occurrs avoids replay
 967 * of transactions where the metadata is already on disk.
 968 */
 969int
 970xfs_log_need_covered(xfs_mount_t *mp)
 971{
 972        int             needed = 0;
 973        struct xlog     *log = mp->m_log;
 974
 975        if (!xfs_fs_writable(mp))
 976                return 0;
 977
 978        spin_lock(&log->l_icloglock);
 979        switch (log->l_covered_state) {
 980        case XLOG_STATE_COVER_DONE:
 981        case XLOG_STATE_COVER_DONE2:
 982        case XLOG_STATE_COVER_IDLE:
 983                break;
 984        case XLOG_STATE_COVER_NEED:
 985        case XLOG_STATE_COVER_NEED2:
 986                if (!xfs_ail_min_lsn(log->l_ailp) &&
 987                    xlog_iclogs_empty(log)) {
 988                        if (log->l_covered_state == XLOG_STATE_COVER_NEED)
 989                                log->l_covered_state = XLOG_STATE_COVER_DONE;
 990                        else
 991                                log->l_covered_state = XLOG_STATE_COVER_DONE2;
 992                }
 993                /* FALLTHRU */
 994        default:
 995                needed = 1;
 996                break;
 997        }
 998        spin_unlock(&log->l_icloglock);
 999        return needed;
1000}
1001
1002/*
1003 * We may be holding the log iclog lock upon entering this routine.
1004 */
1005xfs_lsn_t
1006xlog_assign_tail_lsn_locked(
1007        struct xfs_mount        *mp)
1008{
1009        struct xlog             *log = mp->m_log;
1010        struct xfs_log_item     *lip;
1011        xfs_lsn_t               tail_lsn;
1012
1013        assert_spin_locked(&mp->m_ail->xa_lock);
1014
1015        /*
1016         * To make sure we always have a valid LSN for the log tail we keep
1017         * track of the last LSN which was committed in log->l_last_sync_lsn,
1018         * and use that when the AIL was empty.
1019         */
1020        lip = xfs_ail_min(mp->m_ail);
1021        if (lip)
1022                tail_lsn = lip->li_lsn;
1023        else
1024                tail_lsn = atomic64_read(&log->l_last_sync_lsn);
1025        atomic64_set(&log->l_tail_lsn, tail_lsn);
1026        return tail_lsn;
1027}
1028
1029xfs_lsn_t
1030xlog_assign_tail_lsn(
1031        struct xfs_mount        *mp)
1032{
1033        xfs_lsn_t               tail_lsn;
1034
1035        spin_lock(&mp->m_ail->xa_lock);
1036        tail_lsn = xlog_assign_tail_lsn_locked(mp);
1037        spin_unlock(&mp->m_ail->xa_lock);
1038
1039        return tail_lsn;
1040}
1041
1042/*
1043 * Return the space in the log between the tail and the head.  The head
1044 * is passed in the cycle/bytes formal parms.  In the special case where
1045 * the reserve head has wrapped passed the tail, this calculation is no
1046 * longer valid.  In this case, just return 0 which means there is no space
1047 * in the log.  This works for all places where this function is called
1048 * with the reserve head.  Of course, if the write head were to ever
1049 * wrap the tail, we should blow up.  Rather than catch this case here,
1050 * we depend on other ASSERTions in other parts of the code.   XXXmiken
1051 *
1052 * This code also handles the case where the reservation head is behind
1053 * the tail.  The details of this case are described below, but the end
1054 * result is that we return the size of the log as the amount of space left.
1055 */
1056STATIC int
1057xlog_space_left(
1058        struct xlog     *log,
1059        atomic64_t      *head)
1060{
1061        int             free_bytes;
1062        int             tail_bytes;
1063        int             tail_cycle;
1064        int             head_cycle;
1065        int             head_bytes;
1066
1067        xlog_crack_grant_head(head, &head_cycle, &head_bytes);
1068        xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_bytes);
1069        tail_bytes = BBTOB(tail_bytes);
1070        if (tail_cycle == head_cycle && head_bytes >= tail_bytes)
1071                free_bytes = log->l_logsize - (head_bytes - tail_bytes);
1072        else if (tail_cycle + 1 < head_cycle)
1073                return 0;
1074        else if (tail_cycle < head_cycle) {
1075                ASSERT(tail_cycle == (head_cycle - 1));
1076                free_bytes = tail_bytes - head_bytes;
1077        } else {
1078                /*
1079                 * The reservation head is behind the tail.
1080                 * In this case we just want to return the size of the
1081                 * log as the amount of space left.
1082                 */
1083                xfs_alert(log->l_mp,
1084                        "xlog_space_left: head behind tail\n"
1085                        "  tail_cycle = %d, tail_bytes = %d\n"
1086                        "  GH   cycle = %d, GH   bytes = %d",
1087                        tail_cycle, tail_bytes, head_cycle, head_bytes);
1088                ASSERT(0);
1089                free_bytes = log->l_logsize;
1090        }
1091        return free_bytes;
1092}
1093
1094
1095/*
1096 * Log function which is called when an io completes.
1097 *
1098 * The log manager needs its own routine, in order to control what
1099 * happens with the buffer after the write completes.
1100 */
1101void
1102xlog_iodone(xfs_buf_t *bp)
1103{
1104        struct xlog_in_core     *iclog = bp->b_fspriv;
1105        struct xlog             *l = iclog->ic_log;
1106        int                     aborted = 0;
1107
1108        /*
1109         * Race to shutdown the filesystem if we see an error.
1110         */
1111        if (XFS_TEST_ERROR((xfs_buf_geterror(bp)), l->l_mp,
1112                        XFS_ERRTAG_IODONE_IOERR, XFS_RANDOM_IODONE_IOERR)) {
1113                xfs_buf_ioerror_alert(bp, __func__);
1114                xfs_buf_stale(bp);
1115                xfs_force_shutdown(l->l_mp, SHUTDOWN_LOG_IO_ERROR);
1116                /*
1117                 * This flag will be propagated to the trans-committed
1118                 * callback routines to let them know that the log-commit
1119                 * didn't succeed.
1120                 */
1121                aborted = XFS_LI_ABORTED;
1122        } else if (iclog->ic_state & XLOG_STATE_IOERROR) {
1123                aborted = XFS_LI_ABORTED;
1124        }
1125
1126        /* log I/O is always issued ASYNC */
1127        ASSERT(XFS_BUF_ISASYNC(bp));
1128        xlog_state_done_syncing(iclog, aborted);
1129        /*
1130         * do not reference the buffer (bp) here as we could race
1131         * with it being freed after writing the unmount record to the
1132         * log.
1133         */
1134}
1135
1136/*
1137 * Return size of each in-core log record buffer.
1138 *
1139 * All machines get 8 x 32kB buffers by default, unless tuned otherwise.
1140 *
1141 * If the filesystem blocksize is too large, we may need to choose a
1142 * larger size since the directory code currently logs entire blocks.
1143 */
1144
1145STATIC void
1146xlog_get_iclog_buffer_size(
1147        struct xfs_mount        *mp,
1148        struct xlog             *log)
1149{
1150        int size;
1151        int xhdrs;
1152
1153        if (mp->m_logbufs <= 0)
1154                log->l_iclog_bufs = XLOG_MAX_ICLOGS;
1155        else
1156                log->l_iclog_bufs = mp->m_logbufs;
1157
1158        /*
1159         * Buffer size passed in from mount system call.
1160         */
1161        if (mp->m_logbsize > 0) {
1162                size = log->l_iclog_size = mp->m_logbsize;
1163                log->l_iclog_size_log = 0;
1164                while (size != 1) {
1165                        log->l_iclog_size_log++;
1166                        size >>= 1;
1167                }
1168
1169                if (xfs_sb_version_haslogv2(&mp->m_sb)) {
1170                        /* # headers = size / 32k
1171                         * one header holds cycles from 32k of data
1172                         */
1173
1174                        xhdrs = mp->m_logbsize / XLOG_HEADER_CYCLE_SIZE;
1175                        if (mp->m_logbsize % XLOG_HEADER_CYCLE_SIZE)
1176                                xhdrs++;
1177                        log->l_iclog_hsize = xhdrs << BBSHIFT;
1178                        log->l_iclog_heads = xhdrs;
1179                } else {
1180                        ASSERT(mp->m_logbsize <= XLOG_BIG_RECORD_BSIZE);
1181                        log->l_iclog_hsize = BBSIZE;
1182                        log->l_iclog_heads = 1;
1183                }
1184                goto done;
1185        }
1186
1187        /* All machines use 32kB buffers by default. */
1188        log->l_iclog_size = XLOG_BIG_RECORD_BSIZE;
1189        log->l_iclog_size_log = XLOG_BIG_RECORD_BSHIFT;
1190
1191        /* the default log size is 16k or 32k which is one header sector */
1192        log->l_iclog_hsize = BBSIZE;
1193        log->l_iclog_heads = 1;
1194
1195done:
1196        /* are we being asked to make the sizes selected above visible? */
1197        if (mp->m_logbufs == 0)
1198                mp->m_logbufs = log->l_iclog_bufs;
1199        if (mp->m_logbsize == 0)
1200                mp->m_logbsize = log->l_iclog_size;
1201}       /* xlog_get_iclog_buffer_size */
1202
1203
1204void
1205xfs_log_work_queue(
1206        struct xfs_mount        *mp)
1207{
1208        queue_delayed_work(mp->m_log_workqueue, &mp->m_log->l_work,
1209                                msecs_to_jiffies(xfs_syncd_centisecs * 10));
1210}
1211
1212/*
1213 * Every sync period we need to unpin all items in the AIL and push them to
1214 * disk. If there is nothing dirty, then we might need to cover the log to
1215 * indicate that the filesystem is idle.
1216 */
1217void
1218xfs_log_worker(
1219        struct work_struct      *work)
1220{
1221        struct xlog             *log = container_of(to_delayed_work(work),
1222                                                struct xlog, l_work);
1223        struct xfs_mount        *mp = log->l_mp;
1224
1225        /* dgc: errors ignored - not fatal and nowhere to report them */
1226        if (xfs_log_need_covered(mp))
1227                xfs_fs_log_dummy(mp);
1228        else
1229                xfs_log_force(mp, 0);
1230
1231        /* start pushing all the metadata that is currently dirty */
1232        xfs_ail_push_all(mp->m_ail);
1233
1234        /* queue us up again */
1235        xfs_log_work_queue(mp);
1236}
1237
1238/*
1239 * This routine initializes some of the log structure for a given mount point.
1240 * Its primary purpose is to fill in enough, so recovery can occur.  However,
1241 * some other stuff may be filled in too.
1242 */
1243STATIC struct xlog *
1244xlog_alloc_log(
1245        struct xfs_mount        *mp,
1246        struct xfs_buftarg      *log_target,
1247        xfs_daddr_t             blk_offset,
1248        int                     num_bblks)
1249{
1250        struct xlog             *log;
1251        xlog_rec_header_t       *head;
1252        xlog_in_core_t          **iclogp;
1253        xlog_in_core_t          *iclog, *prev_iclog=NULL;
1254        xfs_buf_t               *bp;
1255        int                     i;
1256        int                     error = ENOMEM;
1257        uint                    log2_size = 0;
1258
1259        log = kmem_zalloc(sizeof(struct xlog), KM_MAYFAIL);
1260        if (!log) {
1261                xfs_warn(mp, "Log allocation failed: No memory!");
1262                goto out;
1263        }
1264
1265        log->l_mp          = mp;
1266        log->l_targ        = log_target;
1267        log->l_logsize     = BBTOB(num_bblks);
1268        log->l_logBBstart  = blk_offset;
1269        log->l_logBBsize   = num_bblks;
1270        log->l_covered_state = XLOG_STATE_COVER_IDLE;
1271        log->l_flags       |= XLOG_ACTIVE_RECOVERY;
1272        INIT_DELAYED_WORK(&log->l_work, xfs_log_worker);
1273
1274        log->l_prev_block  = -1;
1275        /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
1276        xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0);
1277        xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
1278        log->l_curr_cycle  = 1;     /* 0 is bad since this is initial value */
1279
1280        xlog_grant_head_init(&log->l_reserve_head);
1281        xlog_grant_head_init(&log->l_write_head);
1282
1283        error = EFSCORRUPTED;
1284        if (xfs_sb_version_hassector(&mp->m_sb)) {
1285                log2_size = mp->m_sb.sb_logsectlog;
1286                if (log2_size < BBSHIFT) {
1287                        xfs_warn(mp, "Log sector size too small (0x%x < 0x%x)",
1288                                log2_size, BBSHIFT);
1289                        goto out_free_log;
1290                }
1291
1292                log2_size -= BBSHIFT;
1293                if (log2_size > mp->m_sectbb_log) {
1294                        xfs_warn(mp, "Log sector size too large (0x%x > 0x%x)",
1295                                log2_size, mp->m_sectbb_log);
1296                        goto out_free_log;
1297                }
1298
1299                /* for larger sector sizes, must have v2 or external log */
1300                if (log2_size && log->l_logBBstart > 0 &&
1301                            !xfs_sb_version_haslogv2(&mp->m_sb)) {
1302                        xfs_warn(mp,
1303                "log sector size (0x%x) invalid for configuration.",
1304                                log2_size);
1305                        goto out_free_log;
1306                }
1307        }
1308        log->l_sectBBsize = 1 << log2_size;
1309
1310        xlog_get_iclog_buffer_size(mp, log);
1311
1312        error = ENOMEM;
1313        bp = xfs_buf_alloc(mp->m_logdev_targp, 0, BTOBB(log->l_iclog_size), 0);
1314        if (!bp)
1315                goto out_free_log;
1316        bp->b_iodone = xlog_iodone;
1317        ASSERT(xfs_buf_islocked(bp));
1318        log->l_xbuf = bp;
1319
1320        spin_lock_init(&log->l_icloglock);
1321        init_waitqueue_head(&log->l_flush_wait);
1322
1323        iclogp = &log->l_iclog;
1324        /*
1325         * The amount of memory to allocate for the iclog structure is
1326         * rather funky due to the way the structure is defined.  It is
1327         * done this way so that we can use different sizes for machines
1328         * with different amounts of memory.  See the definition of
1329         * xlog_in_core_t in xfs_log_priv.h for details.
1330         */
1331        ASSERT(log->l_iclog_size >= 4096);
1332        for (i=0; i < log->l_iclog_bufs; i++) {
1333                *iclogp = kmem_zalloc(sizeof(xlog_in_core_t), KM_MAYFAIL);
1334                if (!*iclogp)
1335                        goto out_free_iclog;
1336
1337                iclog = *iclogp;
1338                iclog->ic_prev = prev_iclog;
1339                prev_iclog = iclog;
1340
1341                bp = xfs_buf_get_uncached(mp->m_logdev_targp,
1342                                                BTOBB(log->l_iclog_size), 0);
1343                if (!bp)
1344                        goto out_free_iclog;
1345
1346                bp->b_iodone = xlog_iodone;
1347                iclog->ic_bp = bp;
1348                iclog->ic_data = bp->b_addr;
1349#ifdef DEBUG
1350                log->l_iclog_bak[i] = (xfs_caddr_t)&(iclog->ic_header);
1351#endif
1352                head = &iclog->ic_header;
1353                memset(head, 0, sizeof(xlog_rec_header_t));
1354                head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1355                head->h_version = cpu_to_be32(
1356                        xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? 2 : 1);
1357                head->h_size = cpu_to_be32(log->l_iclog_size);
1358                /* new fields */
1359                head->h_fmt = cpu_to_be32(XLOG_FMT);
1360                memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));
1361
1362                iclog->ic_size = BBTOB(bp->b_length) - log->l_iclog_hsize;
1363                iclog->ic_state = XLOG_STATE_ACTIVE;
1364                iclog->ic_log = log;
1365                atomic_set(&iclog->ic_refcnt, 0);
1366                spin_lock_init(&iclog->ic_callback_lock);
1367                iclog->ic_callback_tail = &(iclog->ic_callback);
1368                iclog->ic_datap = (char *)iclog->ic_data + log->l_iclog_hsize;
1369
1370                ASSERT(xfs_buf_islocked(iclog->ic_bp));
1371                init_waitqueue_head(&iclog->ic_force_wait);
1372                init_waitqueue_head(&iclog->ic_write_wait);
1373
1374                iclogp = &iclog->ic_next;
1375        }
1376        *iclogp = log->l_iclog;                 /* complete ring */
1377        log->l_iclog->ic_prev = prev_iclog;     /* re-write 1st prev ptr */
1378
1379        error = xlog_cil_init(log);
1380        if (error)
1381                goto out_free_iclog;
1382        return log;
1383
1384out_free_iclog:
1385        for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
1386                prev_iclog = iclog->ic_next;
1387                if (iclog->ic_bp)
1388                        xfs_buf_free(iclog->ic_bp);
1389                kmem_free(iclog);
1390        }
1391        spinlock_destroy(&log->l_icloglock);
1392        xfs_buf_free(log->l_xbuf);
1393out_free_log:
1394        kmem_free(log);
1395out:
1396        return ERR_PTR(-error);
1397}       /* xlog_alloc_log */
1398
1399
1400/*
1401 * Write out the commit record of a transaction associated with the given
1402 * ticket.  Return the lsn of the commit record.
1403 */
1404STATIC int
1405xlog_commit_record(
1406        struct xlog             *log,
1407        struct xlog_ticket      *ticket,
1408        struct xlog_in_core     **iclog,
1409        xfs_lsn_t               *commitlsnp)
1410{
1411        struct xfs_mount *mp = log->l_mp;
1412        int     error;
1413        struct xfs_log_iovec reg = {
1414                .i_addr = NULL,
1415                .i_len = 0,
1416                .i_type = XLOG_REG_TYPE_COMMIT,
1417        };
1418        struct xfs_log_vec vec = {
1419                .lv_niovecs = 1,
1420                .lv_iovecp = &reg,
1421        };
1422
1423        ASSERT_ALWAYS(iclog);
1424        error = xlog_write(log, &vec, ticket, commitlsnp, iclog,
1425                                        XLOG_COMMIT_TRANS);
1426        if (error)
1427                xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
1428        return error;
1429}
1430
1431/*
1432 * Push on the buffer cache code if we ever use more than 75% of the on-disk
1433 * log space.  This code pushes on the lsn which would supposedly free up
1434 * the 25% which we want to leave free.  We may need to adopt a policy which
1435 * pushes on an lsn which is further along in the log once we reach the high
1436 * water mark.  In this manner, we would be creating a low water mark.
1437 */
1438STATIC void
1439xlog_grant_push_ail(
1440        struct xlog     *log,
1441        int             need_bytes)
1442{
1443        xfs_lsn_t       threshold_lsn = 0;
1444        xfs_lsn_t       last_sync_lsn;
1445        int             free_blocks;
1446        int             free_bytes;
1447        int             threshold_block;
1448        int             threshold_cycle;
1449        int             free_threshold;
1450
1451        ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
1452
1453        free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
1454        free_blocks = BTOBBT(free_bytes);
1455
1456        /*
1457         * Set the threshold for the minimum number of free blocks in the
1458         * log to the maximum of what the caller needs, one quarter of the
1459         * log, and 256 blocks.
1460         */
1461        free_threshold = BTOBB(need_bytes);
1462        free_threshold = MAX(free_threshold, (log->l_logBBsize >> 2));
1463        free_threshold = MAX(free_threshold, 256);
1464        if (free_blocks >= free_threshold)
1465                return;
1466
1467        xlog_crack_atomic_lsn(&log->l_tail_lsn, &threshold_cycle,
1468                                                &threshold_block);
1469        threshold_block += free_threshold;
1470        if (threshold_block >= log->l_logBBsize) {
1471                threshold_block -= log->l_logBBsize;
1472                threshold_cycle += 1;
1473        }
1474        threshold_lsn = xlog_assign_lsn(threshold_cycle,
1475                                        threshold_block);
1476        /*
1477         * Don't pass in an lsn greater than the lsn of the last
1478         * log record known to be on disk. Use a snapshot of the last sync lsn
1479         * so that it doesn't change between the compare and the set.
1480         */
1481        last_sync_lsn = atomic64_read(&log->l_last_sync_lsn);
1482        if (XFS_LSN_CMP(threshold_lsn, last_sync_lsn) > 0)
1483                threshold_lsn = last_sync_lsn;
1484
1485        /*
1486         * Get the transaction layer to kick the dirty buffers out to
1487         * disk asynchronously. No point in trying to do this if
1488         * the filesystem is shutting down.
1489         */
1490        if (!XLOG_FORCED_SHUTDOWN(log))
1491                xfs_ail_push(log->l_ailp, threshold_lsn);
1492}
1493
1494/*
1495 * Stamp cycle number in every block
1496 */
1497STATIC void
1498xlog_pack_data(
1499        struct xlog             *log,
1500        struct xlog_in_core     *iclog,
1501        int                     roundoff)
1502{
1503        int                     i, j, k;
1504        int                     size = iclog->ic_offset + roundoff;
1505        __be32                  cycle_lsn;
1506        xfs_caddr_t             dp;
1507
1508        cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn);
1509
1510        dp = iclog->ic_datap;
1511        for (i = 0; i < BTOBB(size); i++) {
1512                if (i >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE))
1513                        break;
1514                iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp;
1515                *(__be32 *)dp = cycle_lsn;
1516                dp += BBSIZE;
1517        }
1518
1519        if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1520                xlog_in_core_2_t *xhdr = iclog->ic_data;
1521
1522                for ( ; i < BTOBB(size); i++) {
1523                        j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1524                        k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
1525                        xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp;
1526                        *(__be32 *)dp = cycle_lsn;
1527                        dp += BBSIZE;
1528                }
1529
1530                for (i = 1; i < log->l_iclog_heads; i++)
1531                        xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
1532        }
1533}
1534
1535/*
1536 * Calculate the checksum for a log buffer.
1537 *
1538 * This is a little more complicated than it should be because the various
1539 * headers and the actual data are non-contiguous.
1540 */
1541__le32
1542xlog_cksum(
1543        struct xlog             *log,
1544        struct xlog_rec_header  *rhead,
1545        char                    *dp,
1546        int                     size)
1547{
1548        __uint32_t              crc;
1549
1550        /* first generate the crc for the record header ... */
1551        crc = xfs_start_cksum((char *)rhead,
1552                              sizeof(struct xlog_rec_header),
1553                              offsetof(struct xlog_rec_header, h_crc));
1554
1555        /* ... then for additional cycle data for v2 logs ... */
1556        if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
1557                union xlog_in_core2 *xhdr = (union xlog_in_core2 *)rhead;
1558                int             i;
1559
1560                for (i = 1; i < log->l_iclog_heads; i++) {
1561                        crc = crc32c(crc, &xhdr[i].hic_xheader,
1562                                     sizeof(struct xlog_rec_ext_header));
1563                }
1564        }
1565
1566        /* ... and finally for the payload */
1567        crc = crc32c(crc, dp, size);
1568
1569        return xfs_end_cksum(crc);
1570}
1571
1572/*
1573 * The bdstrat callback function for log bufs. This gives us a central
1574 * place to trap bufs in case we get hit by a log I/O error and need to
1575 * shutdown. Actually, in practice, even when we didn't get a log error,
1576 * we transition the iclogs to IOERROR state *after* flushing all existing
1577 * iclogs to disk. This is because we don't want anymore new transactions to be
1578 * started or completed afterwards.
1579 */
1580STATIC int
1581xlog_bdstrat(
1582        struct xfs_buf          *bp)
1583{
1584        struct xlog_in_core     *iclog = bp->b_fspriv;
1585
1586        if (iclog->ic_state & XLOG_STATE_IOERROR) {
1587                xfs_buf_ioerror(bp, EIO);
1588                xfs_buf_stale(bp);
1589                xfs_buf_ioend(bp, 0);
1590                /*
1591                 * It would seem logical to return EIO here, but we rely on
1592                 * the log state machine to propagate I/O errors instead of
1593                 * doing it here.
1594                 */
1595                return 0;
1596        }
1597
1598        xfs_buf_iorequest(bp);
1599        return 0;
1600}
1601
1602/*
1603 * Flush out the in-core log (iclog) to the on-disk log in an asynchronous 
1604 * fashion.  Previously, we should have moved the current iclog
1605 * ptr in the log to point to the next available iclog.  This allows further
1606 * write to continue while this code syncs out an iclog ready to go.
1607 * Before an in-core log can be written out, the data section must be scanned
1608 * to save away the 1st word of each BBSIZE block into the header.  We replace
1609 * it with the current cycle count.  Each BBSIZE block is tagged with the
1610 * cycle count because there in an implicit assumption that drives will
1611 * guarantee that entire 512 byte blocks get written at once.  In other words,
1612 * we can't have part of a 512 byte block written and part not written.  By
1613 * tagging each block, we will know which blocks are valid when recovering
1614 * after an unclean shutdown.
1615 *
1616 * This routine is single threaded on the iclog.  No other thread can be in
1617 * this routine with the same iclog.  Changing contents of iclog can there-
1618 * fore be done without grabbing the state machine lock.  Updating the global
1619 * log will require grabbing the lock though.
1620 *
1621 * The entire log manager uses a logical block numbering scheme.  Only
1622 * log_sync (and then only bwrite()) know about the fact that the log may
1623 * not start with block zero on a given device.  The log block start offset
1624 * is added immediately before calling bwrite().
1625 */
1626
1627STATIC int
1628xlog_sync(
1629        struct xlog             *log,
1630        struct xlog_in_core     *iclog)
1631{
1632        xfs_buf_t       *bp;
1633        int             i;
1634        uint            count;          /* byte count of bwrite */
1635        uint            count_init;     /* initial count before roundup */
1636        int             roundoff;       /* roundoff to BB or stripe */
1637        int             split = 0;      /* split write into two regions */
1638        int             error;
1639        int             v2 = xfs_sb_version_haslogv2(&log->l_mp->m_sb);
1640        int             size;
1641
1642        XFS_STATS_INC(xs_log_writes);
1643        ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
1644
1645        /* Add for LR header */
1646        count_init = log->l_iclog_hsize + iclog->ic_offset;
1647
1648        /* Round out the log write size */
1649        if (v2 && log->l_mp->m_sb.sb_logsunit > 1) {
1650                /* we have a v2 stripe unit to use */
1651                count = XLOG_LSUNITTOB(log, XLOG_BTOLSUNIT(log, count_init));
1652        } else {
1653                count = BBTOB(BTOBB(count_init));
1654        }
1655        roundoff = count - count_init;
1656        ASSERT(roundoff >= 0);
1657        ASSERT((v2 && log->l_mp->m_sb.sb_logsunit > 1 && 
1658                roundoff < log->l_mp->m_sb.sb_logsunit)
1659                || 
1660                (log->l_mp->m_sb.sb_logsunit <= 1 && 
1661                 roundoff < BBTOB(1)));
1662
1663        /* move grant heads by roundoff in sync */
1664        xlog_grant_add_space(log, &log->l_reserve_head.grant, roundoff);
1665        xlog_grant_add_space(log, &log->l_write_head.grant, roundoff);
1666
1667        /* put cycle number in every block */
1668        xlog_pack_data(log, iclog, roundoff); 
1669
1670        /* real byte length */
1671        size = iclog->ic_offset;
1672        if (v2)
1673                size += roundoff;
1674        iclog->ic_header.h_len = cpu_to_be32(size);
1675
1676        bp = iclog->ic_bp;
1677        XFS_BUF_SET_ADDR(bp, BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn)));
1678
1679        XFS_STATS_ADD(xs_log_blocks, BTOBB(count));
1680
1681        /* Do we need to split this write into 2 parts? */
1682        if (XFS_BUF_ADDR(bp) + BTOBB(count) > log->l_logBBsize) {
1683                char            *dptr;
1684
1685                split = count - (BBTOB(log->l_logBBsize - XFS_BUF_ADDR(bp)));
1686                count = BBTOB(log->l_logBBsize - XFS_BUF_ADDR(bp));
1687                iclog->ic_bwritecnt = 2;
1688
1689                /*
1690                 * Bump the cycle numbers at the start of each block in the
1691                 * part of the iclog that ends up in the buffer that gets
1692                 * written to the start of the log.
1693                 *
1694                 * Watch out for the header magic number case, though.
1695                 */
1696                dptr = (char *)&iclog->ic_header + count;
1697                for (i = 0; i < split; i += BBSIZE) {
1698                        __uint32_t cycle = be32_to_cpu(*(__be32 *)dptr);
1699                        if (++cycle == XLOG_HEADER_MAGIC_NUM)
1700                                cycle++;
1701                        *(__be32 *)dptr = cpu_to_be32(cycle);
1702
1703                        dptr += BBSIZE;
1704                }
1705        } else {
1706                iclog->ic_bwritecnt = 1;
1707        }
1708
1709        /* calculcate the checksum */
1710        iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header,
1711                                            iclog->ic_datap, size);
1712
1713        bp->b_io_length = BTOBB(count);
1714        bp->b_fspriv = iclog;
1715        XFS_BUF_ZEROFLAGS(bp);
1716        XFS_BUF_ASYNC(bp);
1717        bp->b_flags |= XBF_SYNCIO;
1718
1719        if (log->l_mp->m_flags & XFS_MOUNT_BARRIER) {
1720                bp->b_flags |= XBF_FUA;
1721
1722                /*
1723                 * Flush the data device before flushing the log to make
1724                 * sure all meta data written back from the AIL actually made
1725                 * it to disk before stamping the new log tail LSN into the
1726                 * log buffer.  For an external log we need to issue the
1727                 * flush explicitly, and unfortunately synchronously here;
1728                 * for an internal log we can simply use the block layer
1729                 * state machine for preflushes.
1730                 */
1731                if (log->l_mp->m_logdev_targp != log->l_mp->m_ddev_targp)
1732                        xfs_blkdev_issue_flush(log->l_mp->m_ddev_targp);
1733                else
1734                        bp->b_flags |= XBF_FLUSH;
1735        }
1736
1737        ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1);
1738        ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize);
1739
1740        xlog_verify_iclog(log, iclog, count, B_TRUE);
1741
1742        /* account for log which doesn't start at block #0 */
1743        XFS_BUF_SET_ADDR(bp, XFS_BUF_ADDR(bp) + log->l_logBBstart);
1744        /*
1745         * Don't call xfs_bwrite here. We do log-syncs even when the filesystem
1746         * is shutting down.
1747         */
1748        XFS_BUF_WRITE(bp);
1749
1750        error = xlog_bdstrat(bp);
1751        if (error) {
1752                xfs_buf_ioerror_alert(bp, "xlog_sync");
1753                return error;
1754        }
1755        if (split) {
1756                bp = iclog->ic_log->l_xbuf;
1757                XFS_BUF_SET_ADDR(bp, 0);             /* logical 0 */
1758                xfs_buf_associate_memory(bp,
1759                                (char *)&iclog->ic_header + count, split);
1760                bp->b_fspriv = iclog;
1761                XFS_BUF_ZEROFLAGS(bp);
1762                XFS_BUF_ASYNC(bp);
1763                bp->b_flags |= XBF_SYNCIO;
1764                if (log->l_mp->m_flags & XFS_MOUNT_BARRIER)
1765                        bp->b_flags |= XBF_FUA;
1766
1767                ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1);
1768                ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize);
1769
1770                /* account for internal log which doesn't start at block #0 */
1771                XFS_BUF_SET_ADDR(bp, XFS_BUF_ADDR(bp) + log->l_logBBstart);
1772                XFS_BUF_WRITE(bp);
1773                error = xlog_bdstrat(bp);
1774                if (error) {
1775                        xfs_buf_ioerror_alert(bp, "xlog_sync (split)");
1776                        return error;
1777                }
1778        }
1779        return 0;
1780}       /* xlog_sync */
1781
1782/*
1783 * Deallocate a log structure
1784 */
1785STATIC void
1786xlog_dealloc_log(
1787        struct xlog     *log)
1788{
1789        xlog_in_core_t  *iclog, *next_iclog;
1790        int             i;
1791
1792        xlog_cil_destroy(log);
1793
1794        /*
1795         * always need to ensure that the extra buffer does not point to memory
1796         * owned by another log buffer before we free it.
1797         */
1798        xfs_buf_set_empty(log->l_xbuf, BTOBB(log->l_iclog_size));
1799        xfs_buf_free(log->l_xbuf);
1800
1801        iclog = log->l_iclog;
1802        for (i=0; i<log->l_iclog_bufs; i++) {
1803                xfs_buf_free(iclog->ic_bp);
1804                next_iclog = iclog->ic_next;
1805                kmem_free(iclog);
1806                iclog = next_iclog;
1807        }
1808        spinlock_destroy(&log->l_icloglock);
1809
1810        log->l_mp->m_log = NULL;
1811        kmem_free(log);
1812}       /* xlog_dealloc_log */
1813
1814/*
1815 * Update counters atomically now that memcpy is done.
1816 */
1817/* ARGSUSED */
1818static inline void
1819xlog_state_finish_copy(
1820        struct xlog             *log,
1821        struct xlog_in_core     *iclog,
1822        int                     record_cnt,
1823        int                     copy_bytes)
1824{
1825        spin_lock(&log->l_icloglock);
1826
1827        be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
1828        iclog->ic_offset += copy_bytes;
1829
1830        spin_unlock(&log->l_icloglock);
1831}       /* xlog_state_finish_copy */
1832
1833
1834
1835
1836/*
1837 * print out info relating to regions written which consume
1838 * the reservation
1839 */
1840void
1841xlog_print_tic_res(
1842        struct xfs_mount        *mp,
1843        struct xlog_ticket      *ticket)
1844{
1845        uint i;
1846        uint ophdr_spc = ticket->t_res_num_ophdrs * (uint)sizeof(xlog_op_header_t);
1847
1848        /* match with XLOG_REG_TYPE_* in xfs_log.h */
1849        static char *res_type_str[XLOG_REG_TYPE_MAX] = {
1850            "bformat",
1851            "bchunk",
1852            "efi_format",
1853            "efd_format",
1854            "iformat",
1855            "icore",
1856            "iext",
1857            "ibroot",
1858            "ilocal",
1859            "iattr_ext",
1860            "iattr_broot",
1861            "iattr_local",
1862            "qformat",
1863            "dquot",
1864            "quotaoff",
1865            "LR header",
1866            "unmount",
1867            "commit",
1868            "trans header"
1869        };
1870        static char *trans_type_str[XFS_TRANS_TYPE_MAX] = {
1871            "SETATTR_NOT_SIZE",
1872            "SETATTR_SIZE",
1873            "INACTIVE",
1874            "CREATE",
1875            "CREATE_TRUNC",
1876            "TRUNCATE_FILE",
1877            "REMOVE",
1878            "LINK",
1879            "RENAME",
1880            "MKDIR",
1881            "RMDIR",
1882            "SYMLINK",
1883            "SET_DMATTRS",
1884            "GROWFS",
1885            "STRAT_WRITE",
1886            "DIOSTRAT",
1887            "WRITE_SYNC",
1888            "WRITEID",
1889            "ADDAFORK",
1890            "ATTRINVAL",
1891            "ATRUNCATE",
1892            "ATTR_SET",
1893            "ATTR_RM",
1894            "ATTR_FLAG",
1895            "CLEAR_AGI_BUCKET",
1896            "QM_SBCHANGE",
1897            "DUMMY1",
1898            "DUMMY2",
1899            "QM_QUOTAOFF",
1900            "QM_DQALLOC",
1901            "QM_SETQLIM",
1902            "QM_DQCLUSTER",
1903            "QM_QINOCREATE",
1904            "QM_QUOTAOFF_END",
1905            "SB_UNIT",
1906            "FSYNC_TS",
1907            "GROWFSRT_ALLOC",
1908            "GROWFSRT_ZERO",
1909            "GROWFSRT_FREE",
1910            "SWAPEXT"
1911        };
1912
1913        xfs_warn(mp,
1914                "xlog_write: reservation summary:\n"
1915                "  trans type  = %s (%u)\n"
1916                "  unit res    = %d bytes\n"
1917                "  current res = %d bytes\n"
1918                "  total reg   = %u bytes (o/flow = %u bytes)\n"
1919                "  ophdrs      = %u (ophdr space = %u bytes)\n"
1920                "  ophdr + reg = %u bytes\n"
1921                "  num regions = %u\n",
1922                ((ticket->t_trans_type <= 0 ||
1923                  ticket->t_trans_type > XFS_TRANS_TYPE_MAX) ?
1924                  "bad-trans-type" : trans_type_str[ticket->t_trans_type-1]),
1925                ticket->t_trans_type,
1926                ticket->t_unit_res,
1927                ticket->t_curr_res,
1928                ticket->t_res_arr_sum, ticket->t_res_o_flow,
1929                ticket->t_res_num_ophdrs, ophdr_spc,
1930                ticket->t_res_arr_sum +
1931                ticket->t_res_o_flow + ophdr_spc,
1932                ticket->t_res_num);
1933
1934        for (i = 0; i < ticket->t_res_num; i++) {
1935                uint r_type = ticket->t_res_arr[i].r_type;
1936                xfs_warn(mp, "region[%u]: %s - %u bytes\n", i,
1937                            ((r_type <= 0 || r_type > XLOG_REG_TYPE_MAX) ?
1938                            "bad-rtype" : res_type_str[r_type-1]),
1939                            ticket->t_res_arr[i].r_len);
1940        }
1941
1942        xfs_alert_tag(mp, XFS_PTAG_LOGRES,
1943                "xlog_write: reservation ran out. Need to up reservation");
1944        xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
1945}
1946
1947/*
1948 * Calculate the potential space needed by the log vector.  Each region gets
1949 * its own xlog_op_header_t and may need to be double word aligned.
1950 */
1951static int
1952xlog_write_calc_vec_length(
1953        struct xlog_ticket      *ticket,
1954        struct xfs_log_vec      *log_vector)
1955{
1956        struct xfs_log_vec      *lv;
1957        int                     headers = 0;
1958        int                     len = 0;
1959        int                     i;
1960
1961        /* acct for start rec of xact */
1962        if (ticket->t_flags & XLOG_TIC_INITED)
1963                headers++;
1964
1965        for (lv = log_vector; lv; lv = lv->lv_next) {
1966                headers += lv->lv_niovecs;
1967
1968                for (i = 0; i < lv->lv_niovecs; i++) {
1969                        struct xfs_log_iovec    *vecp = &lv->lv_iovecp[i];
1970
1971                        len += vecp->i_len;
1972                        xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type);
1973                }
1974        }
1975
1976        ticket->t_res_num_ophdrs += headers;
1977        len += headers * sizeof(struct xlog_op_header);
1978
1979        return len;
1980}
1981
1982/*
1983 * If first write for transaction, insert start record  We can't be trying to
1984 * commit if we are inited.  We can't have any "partial_copy" if we are inited.
1985 */
1986static int
1987xlog_write_start_rec(
1988        struct xlog_op_header   *ophdr,
1989        struct xlog_ticket      *ticket)
1990{
1991        if (!(ticket->t_flags & XLOG_TIC_INITED))
1992                return 0;
1993
1994        ophdr->oh_tid   = cpu_to_be32(ticket->t_tid);
1995        ophdr->oh_clientid = ticket->t_clientid;
1996        ophdr->oh_len = 0;
1997        ophdr->oh_flags = XLOG_START_TRANS;
1998        ophdr->oh_res2 = 0;
1999
2000        ticket->t_flags &= ~XLOG_TIC_INITED;
2001
2002        return sizeof(struct xlog_op_header);
2003}
2004
2005static xlog_op_header_t *
2006xlog_write_setup_ophdr(
2007        struct xlog             *log,
2008        struct xlog_op_header   *ophdr,
2009        struct xlog_ticket      *ticket,
2010        uint                    flags)
2011{
2012        ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
2013        ophdr->oh_clientid = ticket->t_clientid;
2014        ophdr->oh_res2 = 0;
2015
2016        /* are we copying a commit or unmount record? */
2017        ophdr->oh_flags = flags;
2018
2019        /*
2020         * We've seen logs corrupted with bad transaction client ids.  This
2021         * makes sure that XFS doesn't generate them on.  Turn this into an EIO
2022         * and shut down the filesystem.
2023         */
2024        switch (ophdr->oh_clientid)  {
2025        case XFS_TRANSACTION:
2026        case XFS_VOLUME:
2027        case XFS_LOG:
2028                break;
2029        default:
2030                xfs_warn(log->l_mp,
2031                        "Bad XFS transaction clientid 0x%x in ticket 0x%p",
2032                        ophdr->oh_clientid, ticket);
2033                return NULL;
2034        }
2035
2036        return ophdr;
2037}
2038
2039/*
2040 * Set up the parameters of the region copy into the log. This has
2041 * to handle region write split across multiple log buffers - this
2042 * state is kept external to this function so that this code can
2043 * can be written in an obvious, self documenting manner.
2044 */
2045static int
2046xlog_write_setup_copy(
2047        struct xlog_ticket      *ticket,
2048        struct xlog_op_header   *ophdr,
2049        int                     space_available,
2050        int                     space_required,
2051        int                     *copy_off,
2052        int                     *copy_len,
2053        int                     *last_was_partial_copy,
2054        int                     *bytes_consumed)
2055{
2056        int                     still_to_copy;
2057
2058        still_to_copy = space_required - *bytes_consumed;
2059        *copy_off = *bytes_consumed;
2060
2061        if (still_to_copy <= space_available) {
2062                /* write of region completes here */
2063                *copy_len = still_to_copy;
2064                ophdr->oh_len = cpu_to_be32(*copy_len);
2065                if (*last_was_partial_copy)
2066                        ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
2067                *last_was_partial_copy = 0;
2068                *bytes_consumed = 0;
2069                return 0;
2070        }
2071
2072        /* partial write of region, needs extra log op header reservation */
2073        *copy_len = space_available;
2074        ophdr->oh_len = cpu_to_be32(*copy_len);
2075        ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
2076        if (*last_was_partial_copy)
2077                ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
2078        *bytes_consumed += *copy_len;
2079        (*last_was_partial_copy)++;
2080
2081        /* account for new log op header */
2082        ticket->t_curr_res -= sizeof(struct xlog_op_header);
2083        ticket->t_res_num_ophdrs++;
2084
2085        return sizeof(struct xlog_op_header);
2086}
2087
2088static int
2089xlog_write_copy_finish(
2090        struct xlog             *log,
2091        struct xlog_in_core     *iclog,
2092        uint                    flags,
2093        int                     *record_cnt,
2094        int                     *data_cnt,
2095        int                     *partial_copy,
2096        int                     *partial_copy_len,
2097        int                     log_offset,
2098        struct xlog_in_core     **commit_iclog)
2099{
2100        if (*partial_copy) {
2101                /*
2102                 * This iclog has already been marked WANT_SYNC by
2103                 * xlog_state_get_iclog_space.
2104                 */
2105                xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2106                *record_cnt = 0;
2107                *data_cnt = 0;
2108                return xlog_state_release_iclog(log, iclog);
2109        }
2110
2111        *partial_copy = 0;
2112        *partial_copy_len = 0;
2113
2114        if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
2115                /* no more space in this iclog - push it. */
2116                xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
2117                *record_cnt = 0;
2118                *data_cnt = 0;
2119
2120                spin_lock(&log->l_icloglock);
2121                xlog_state_want_sync(log, iclog);
2122                spin_unlock(&log->l_icloglock);
2123
2124                if (!commit_iclog)
2125                        return xlog_state_release_iclog(log, iclog);
2126                ASSERT(flags & XLOG_COMMIT_TRANS);
2127                *commit_iclog = iclog;
2128        }
2129
2130        return 0;
2131}
2132
2133/*
2134 * Write some region out to in-core log
2135 *
2136 * This will be called when writing externally provided regions or when
2137 * writing out a commit record for a given transaction.
2138 *
2139 * General algorithm:
2140 *      1. Find total length of this write.  This may include adding to the
2141 *              lengths passed in.
2142 *      2. Check whether we violate the tickets reservation.
2143 *      3. While writing to this iclog
2144 *          A. Reserve as much space in this iclog as can get
2145 *          B. If this is first write, save away start lsn
2146 *          C. While writing this region:
2147 *              1. If first write of transaction, write start record
2148 *              2. Write log operation header (header per region)
2149 *              3. Find out if we can fit entire region into this iclog
2150 *              4. Potentially, verify destination memcpy ptr
2151 *              5. Memcpy (partial) region
2152 *              6. If partial copy, release iclog; otherwise, continue
2153 *                      copying more regions into current iclog
2154 *      4. Mark want sync bit (in simulation mode)
2155 *      5. Release iclog for potential flush to on-disk log.
2156 *
2157 * ERRORS:
2158 * 1.   Panic if reservation is overrun.  This should never happen since
2159 *      reservation amounts are generated internal to the filesystem.
2160 * NOTES:
2161 * 1. Tickets are single threaded data structures.
2162 * 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
2163 *      syncing routine.  When a single log_write region needs to span
2164 *      multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
2165 *      on all log operation writes which don't contain the end of the
2166 *      region.  The XLOG_END_TRANS bit is used for the in-core log
2167 *      operation which contains the end of the continued log_write region.
2168 * 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
2169 *      we don't really know exactly how much space will be used.  As a result,
2170 *      we don't update ic_offset until the end when we know exactly how many
2171 *      bytes have been written out.
2172 */
2173int
2174xlog_write(
2175        struct xlog             *log,
2176        struct xfs_log_vec      *log_vector,
2177        struct xlog_ticket      *ticket,
2178        xfs_lsn_t               *start_lsn,
2179        struct xlog_in_core     **commit_iclog,
2180        uint                    flags)
2181{
2182        struct xlog_in_core     *iclog = NULL;
2183        struct xfs_log_iovec    *vecp;
2184        struct xfs_log_vec      *lv;
2185        int                     len;
2186        int                     index;
2187        int                     partial_copy = 0;
2188        int                     partial_copy_len = 0;
2189        int                     contwr = 0;
2190        int                     record_cnt = 0;
2191        int                     data_cnt = 0;
2192        int                     error;
2193
2194        *start_lsn = 0;
2195
2196        len = xlog_write_calc_vec_length(ticket, log_vector);
2197
2198        /*
2199         * Region headers and bytes are already accounted for.
2200         * We only need to take into account start records and
2201         * split regions in this function.
2202         */
2203        if (ticket->t_flags & XLOG_TIC_INITED)
2204                ticket->t_curr_res -= sizeof(xlog_op_header_t);
2205
2206        /*
2207         * Commit record headers need to be accounted for. These
2208         * come in as separate writes so are easy to detect.
2209         */
2210        if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS))
2211                ticket->t_curr_res -= sizeof(xlog_op_header_t);
2212
2213        if (ticket->t_curr_res < 0)
2214                xlog_print_tic_res(log->l_mp, ticket);
2215
2216        index = 0;
2217        lv = log_vector;
2218        vecp = lv->lv_iovecp;
2219        while (lv && index < lv->lv_niovecs) {
2220                void            *ptr;
2221                int             log_offset;
2222
2223                error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
2224                                                   &contwr, &log_offset);
2225                if (error)
2226                        return error;
2227
2228                ASSERT(log_offset <= iclog->ic_size - 1);
2229                ptr = iclog->ic_datap + log_offset;
2230
2231                /* start_lsn is the first lsn written to. That's all we need. */
2232                if (!*start_lsn)
2233                        *start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
2234
2235                /*
2236                 * This loop writes out as many regions as can fit in the amount
2237                 * of space which was allocated by xlog_state_get_iclog_space().
2238                 */
2239                while (lv && index < lv->lv_niovecs) {
2240                        struct xfs_log_iovec    *reg = &vecp[index];
2241                        struct xlog_op_header   *ophdr;
2242                        int                     start_rec_copy;
2243                        int                     copy_len;
2244                        int                     copy_off;
2245
2246                        ASSERT(reg->i_len % sizeof(__int32_t) == 0);
2247                        ASSERT((unsigned long)ptr % sizeof(__int32_t) == 0);
2248
2249                        start_rec_copy = xlog_write_start_rec(ptr, ticket);
2250                        if (start_rec_copy) {
2251                                record_cnt++;
2252                                xlog_write_adv_cnt(&ptr, &len, &log_offset,
2253                                                   start_rec_copy);
2254                        }
2255
2256                        ophdr = xlog_write_setup_ophdr(log, ptr, ticket, flags);
2257                        if (!ophdr)
2258                                return XFS_ERROR(EIO);
2259
2260                        xlog_write_adv_cnt(&ptr, &len, &log_offset,
2261                                           sizeof(struct xlog_op_header));
2262
2263                        len += xlog_write_setup_copy(ticket, ophdr,
2264                                                     iclog->ic_size-log_offset,
2265                                                     reg->i_len,
2266                                                     &copy_off, &copy_len,
2267                                                     &partial_copy,
2268                                                     &partial_copy_len);
2269                        xlog_verify_dest_ptr(log, ptr);
2270
2271                        /* copy region */
2272                        ASSERT(copy_len >= 0);
2273                        memcpy(ptr, reg->i_addr + copy_off, copy_len);
2274                        xlog_write_adv_cnt(&ptr, &len, &log_offset, copy_len);
2275
2276                        copy_len += start_rec_copy + sizeof(xlog_op_header_t);
2277                        record_cnt++;
2278                        data_cnt += contwr ? copy_len : 0;
2279
2280                        error = xlog_write_copy_finish(log, iclog, flags,
2281                                                       &record_cnt, &data_cnt,
2282                                                       &partial_copy,
2283                                                       &partial_copy_len,
2284                                                       log_offset,
2285                                                       commit_iclog);
2286                        if (error)
2287                                return error;
2288
2289                        /*
2290                         * if we had a partial copy, we need to get more iclog
2291                         * space but we don't want to increment the region
2292                         * index because there is still more is this region to
2293                         * write.
2294                         *
2295                         * If we completed writing this region, and we flushed
2296                         * the iclog (indicated by resetting of the record
2297                         * count), then we also need to get more log space. If
2298                         * this was the last record, though, we are done and
2299                         * can just return.
2300                         */
2301                        if (partial_copy)
2302                                break;
2303
2304                        if (++index == lv->lv_niovecs) {
2305                                lv = lv->lv_next;
2306                                index = 0;
2307                                if (lv)
2308                                        vecp = lv->lv_iovecp;
2309                        }
2310                        if (record_cnt == 0) {
2311                                if (!lv)
2312                                        return 0;
2313                                break;
2314                        }
2315                }
2316        }
2317
2318        ASSERT(len == 0);
2319
2320        xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
2321        if (!commit_iclog)
2322                return xlog_state_release_iclog(log, iclog);
2323
2324        ASSERT(flags & XLOG_COMMIT_TRANS);
2325        *commit_iclog = iclog;
2326        return 0;
2327}
2328
2329
2330/*****************************************************************************
2331 *
2332 *              State Machine functions
2333 *
2334 *****************************************************************************
2335 */
2336
2337/* Clean iclogs starting from the head.  This ordering must be
2338 * maintained, so an iclog doesn't become ACTIVE beyond one that
2339 * is SYNCING.  This is also required to maintain the notion that we use
2340 * a ordered wait queue to hold off would be writers to the log when every
2341 * iclog is trying to sync to disk.
2342 *
2343 * State Change: DIRTY -> ACTIVE
2344 */
2345STATIC void
2346xlog_state_clean_log(
2347        struct xlog *log)
2348{
2349        xlog_in_core_t  *iclog;
2350        int changed = 0;
2351
2352        iclog = log->l_iclog;
2353        do {
2354                if (iclog->ic_state == XLOG_STATE_DIRTY) {
2355                        iclog->ic_state = XLOG_STATE_ACTIVE;
2356                        iclog->ic_offset       = 0;
2357                        ASSERT(iclog->ic_callback == NULL);
2358                        /*
2359                         * If the number of ops in this iclog indicate it just
2360                         * contains the dummy transaction, we can
2361                         * change state into IDLE (the second time around).
2362                         * Otherwise we should change the state into
2363                         * NEED a dummy.
2364                         * We don't need to cover the dummy.
2365                         */
2366                        if (!changed &&
2367                           (be32_to_cpu(iclog->ic_header.h_num_logops) ==
2368                                        XLOG_COVER_OPS)) {
2369                                changed = 1;
2370                        } else {
2371                                /*
2372                                 * We have two dirty iclogs so start over
2373                                 * This could also be num of ops indicates
2374                                 * this is not the dummy going out.
2375                                 */
2376                                changed = 2;
2377                        }
2378                        iclog->ic_header.h_num_logops = 0;
2379                        memset(iclog->ic_header.h_cycle_data, 0,
2380                              sizeof(iclog->ic_header.h_cycle_data));
2381                        iclog->ic_header.h_lsn = 0;
2382                } else if (iclog->ic_state == XLOG_STATE_ACTIVE)
2383                        /* do nothing */;
2384                else
2385                        break;  /* stop cleaning */
2386                iclog = iclog->ic_next;
2387        } while (iclog != log->l_iclog);
2388
2389        /* log is locked when we are called */
2390        /*
2391         * Change state for the dummy log recording.
2392         * We usually go to NEED. But we go to NEED2 if the changed indicates
2393         * we are done writing the dummy record.
2394         * If we are done with the second dummy recored (DONE2), then
2395         * we go to IDLE.
2396         */
2397        if (changed) {
2398                switch (log->l_covered_state) {
2399                case XLOG_STATE_COVER_IDLE:
2400                case XLOG_STATE_COVER_NEED:
2401                case XLOG_STATE_COVER_NEED2:
2402                        log->l_covered_state = XLOG_STATE_COVER_NEED;
2403                        break;
2404
2405                case XLOG_STATE_COVER_DONE:
2406                        if (changed == 1)
2407                                log->l_covered_state = XLOG_STATE_COVER_NEED2;
2408                        else
2409                                log->l_covered_state = XLOG_STATE_COVER_NEED;
2410                        break;
2411
2412                case XLOG_STATE_COVER_DONE2:
2413                        if (changed == 1)
2414                                log->l_covered_state = XLOG_STATE_COVER_IDLE;
2415                        else
2416                                log->l_covered_state = XLOG_STATE_COVER_NEED;
2417                        break;
2418
2419                default:
2420                        ASSERT(0);
2421                }
2422        }
2423}       /* xlog_state_clean_log */
2424
2425STATIC xfs_lsn_t
2426xlog_get_lowest_lsn(
2427        struct xlog     *log)
2428{
2429        xlog_in_core_t  *lsn_log;
2430        xfs_lsn_t       lowest_lsn, lsn;
2431
2432        lsn_log = log->l_iclog;
2433        lowest_lsn = 0;
2434        do {
2435            if (!(lsn_log->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY))) {
2436                lsn = be64_to_cpu(lsn_log->ic_header.h_lsn);
2437                if ((lsn && !lowest_lsn) ||
2438                    (XFS_LSN_CMP(lsn, lowest_lsn) < 0)) {
2439                        lowest_lsn = lsn;
2440                }
2441            }
2442            lsn_log = lsn_log->ic_next;
2443        } while (lsn_log != log->l_iclog);
2444        return lowest_lsn;
2445}
2446
2447
2448STATIC void
2449xlog_state_do_callback(
2450        struct xlog             *log,
2451        int                     aborted,
2452        struct xlog_in_core     *ciclog)
2453{
2454        xlog_in_core_t     *iclog;
2455        xlog_in_core_t     *first_iclog;        /* used to know when we've
2456                                                 * processed all iclogs once */
2457        xfs_log_callback_t *cb, *cb_next;
2458        int                flushcnt = 0;
2459        xfs_lsn_t          lowest_lsn;
2460        int                ioerrors;    /* counter: iclogs with errors */
2461        int                loopdidcallbacks; /* flag: inner loop did callbacks*/
2462        int                funcdidcallbacks; /* flag: function did callbacks */
2463        int                repeats;     /* for issuing console warnings if
2464                                         * looping too many times */
2465        int                wake = 0;
2466
2467        spin_lock(&log->l_icloglock);
2468        first_iclog = iclog = log->l_iclog;
2469        ioerrors = 0;
2470        funcdidcallbacks = 0;
2471        repeats = 0;
2472
2473        do {
2474                /*
2475                 * Scan all iclogs starting with the one pointed to by the
2476                 * log.  Reset this starting point each time the log is
2477                 * unlocked (during callbacks).
2478                 *
2479                 * Keep looping through iclogs until one full pass is made
2480                 * without running any callbacks.
2481                 */
2482                first_iclog = log->l_iclog;
2483                iclog = log->l_iclog;
2484                loopdidcallbacks = 0;
2485                repeats++;
2486
2487                do {
2488
2489                        /* skip all iclogs in the ACTIVE & DIRTY states */
2490                        if (iclog->ic_state &
2491                            (XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY)) {
2492                                iclog = iclog->ic_next;
2493                                continue;
2494                        }
2495
2496                        /*
2497                         * Between marking a filesystem SHUTDOWN and stopping
2498                         * the log, we do flush all iclogs to disk (if there
2499                         * wasn't a log I/O error). So, we do want things to
2500                         * go smoothly in case of just a SHUTDOWN  w/o a
2501                         * LOG_IO_ERROR.
2502                         */
2503                        if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
2504                                /*
2505                                 * Can only perform callbacks in order.  Since
2506                                 * this iclog is not in the DONE_SYNC/
2507                                 * DO_CALLBACK state, we skip the rest and
2508                                 * just try to clean up.  If we set our iclog
2509                                 * to DO_CALLBACK, we will not process it when
2510                                 * we retry since a previous iclog is in the
2511                                 * CALLBACK and the state cannot change since
2512                                 * we are holding the l_icloglock.
2513                                 */
2514                                if (!(iclog->ic_state &
2515                                        (XLOG_STATE_DONE_SYNC |
2516                                                 XLOG_STATE_DO_CALLBACK))) {
2517                                        if (ciclog && (ciclog->ic_state ==
2518                                                        XLOG_STATE_DONE_SYNC)) {
2519                                                ciclog->ic_state = XLOG_STATE_DO_CALLBACK;
2520                                        }
2521                                        break;
2522                                }
2523                                /*
2524                                 * We now have an iclog that is in either the
2525                                 * DO_CALLBACK or DONE_SYNC states. The other
2526                                 * states (WANT_SYNC, SYNCING, or CALLBACK were
2527                                 * caught by the above if and are going to
2528                                 * clean (i.e. we aren't doing their callbacks)
2529                                 * see the above if.
2530                                 */
2531
2532                                /*
2533                                 * We will do one more check here to see if we
2534                                 * have chased our tail around.
2535                                 */
2536
2537                                lowest_lsn = xlog_get_lowest_lsn(log);
2538                                if (lowest_lsn &&
2539                                    XFS_LSN_CMP(lowest_lsn,
2540                                                be64_to_cpu(iclog->ic_header.h_lsn)) < 0) {
2541                                        iclog = iclog->ic_next;
2542                                        continue; /* Leave this iclog for
2543                                                   * another thread */
2544                                }
2545
2546                                iclog->ic_state = XLOG_STATE_CALLBACK;
2547
2548
2549                                /*
2550                                 * Completion of a iclog IO does not imply that
2551                                 * a transaction has completed, as transactions
2552                                 * can be large enough to span many iclogs. We
2553                                 * cannot change the tail of the log half way
2554                                 * through a transaction as this may be the only
2555                                 * transaction in the log and moving th etail to
2556                                 * point to the middle of it will prevent
2557                                 * recovery from finding the start of the
2558                                 * transaction. Hence we should only update the
2559                                 * last_sync_lsn if this iclog contains
2560                                 * transaction completion callbacks on it.
2561                                 *
2562                                 * We have to do this before we drop the
2563                                 * icloglock to ensure we are the only one that
2564                                 * can update it.
2565                                 */
2566                                ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
2567                                        be64_to_cpu(iclog->ic_header.h_lsn)) <= 0);
2568                                if (iclog->ic_callback)
2569                                        atomic64_set(&log->l_last_sync_lsn,
2570                                                be64_to_cpu(iclog->ic_header.h_lsn));
2571
2572                        } else
2573                                ioerrors++;
2574
2575                        spin_unlock(&log->l_icloglock);
2576
2577                        /*
2578                         * Keep processing entries in the callback list until
2579                         * we come around and it is empty.  We need to
2580                         * atomically see that the list is empty and change the
2581                         * state to DIRTY so that we don't miss any more
2582                         * callbacks being added.
2583                         */
2584                        spin_lock(&iclog->ic_callback_lock);
2585                        cb = iclog->ic_callback;
2586                        while (cb) {
2587                                iclog->ic_callback_tail = &(iclog->ic_callback);
2588                                iclog->ic_callback = NULL;
2589                                spin_unlock(&iclog->ic_callback_lock);
2590
2591                                /* perform callbacks in the order given */
2592                                for (; cb; cb = cb_next) {
2593                                        cb_next = cb->cb_next;
2594                                        cb->cb_func(cb->cb_arg, aborted);
2595                                }
2596                                spin_lock(&iclog->ic_callback_lock);
2597                                cb = iclog->ic_callback;
2598                        }
2599
2600                        loopdidcallbacks++;
2601                        funcdidcallbacks++;
2602
2603                        spin_lock(&log->l_icloglock);
2604                        ASSERT(iclog->ic_callback == NULL);
2605                        spin_unlock(&iclog->ic_callback_lock);
2606                        if (!(iclog->ic_state & XLOG_STATE_IOERROR))
2607                                iclog->ic_state = XLOG_STATE_DIRTY;
2608
2609                        /*
2610                         * Transition from DIRTY to ACTIVE if applicable.
2611                         * NOP if STATE_IOERROR.
2612                         */
2613                        xlog_state_clean_log(log);
2614
2615                        /* wake up threads waiting in xfs_log_force() */
2616                        wake_up_all(&iclog->ic_force_wait);
2617
2618                        iclog = iclog->ic_next;
2619                } while (first_iclog != iclog);
2620
2621                if (repeats > 5000) {
2622                        flushcnt += repeats;
2623                        repeats = 0;
2624                        xfs_warn(log->l_mp,
2625                                "%s: possible infinite loop (%d iterations)",
2626                                __func__, flushcnt);
2627                }
2628        } while (!ioerrors && loopdidcallbacks);
2629
2630        /*
2631         * make one last gasp attempt to see if iclogs are being left in
2632         * limbo..
2633         */
2634#ifdef DEBUG
2635        if (funcdidcallbacks) {
2636                first_iclog = iclog = log->l_iclog;
2637                do {
2638                        ASSERT(iclog->ic_state != XLOG_STATE_DO_CALLBACK);
2639                        /*
2640                         * Terminate the loop if iclogs are found in states
2641                         * which will cause other threads to clean up iclogs.
2642                         *
2643                         * SYNCING - i/o completion will go through logs
2644                         * DONE_SYNC - interrupt thread should be waiting for
2645                         *              l_icloglock
2646                         * IOERROR - give up hope all ye who enter here
2647                         */
2648                        if (iclog->ic_state == XLOG_STATE_WANT_SYNC ||
2649                            iclog->ic_state == XLOG_STATE_SYNCING ||
2650                            iclog->ic_state == XLOG_STATE_DONE_SYNC ||
2651                            iclog->ic_state == XLOG_STATE_IOERROR )
2652                                break;
2653                        iclog = iclog->ic_next;
2654                } while (first_iclog != iclog);
2655        }
2656#endif
2657
2658        if (log->l_iclog->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_IOERROR))
2659                wake = 1;
2660        spin_unlock(&log->l_icloglock);
2661
2662        if (wake)
2663                wake_up_all(&log->l_flush_wait);
2664}
2665
2666
2667/*
2668 * Finish transitioning this iclog to the dirty state.
2669 *
2670 * Make sure that we completely execute this routine only when this is
2671 * the last call to the iclog.  There is a good chance that iclog flushes,
2672 * when we reach the end of the physical log, get turned into 2 separate
2673 * calls to bwrite.  Hence, one iclog flush could generate two calls to this
2674 * routine.  By using the reference count bwritecnt, we guarantee that only
2675 * the second completion goes through.
2676 *
2677 * Callbacks could take time, so they are done outside the scope of the
2678 * global state machine log lock.
2679 */
2680STATIC void
2681xlog_state_done_syncing(
2682        xlog_in_core_t  *iclog,
2683        int             aborted)
2684{
2685        struct xlog        *log = iclog->ic_log;
2686
2687        spin_lock(&log->l_icloglock);
2688
2689        ASSERT(iclog->ic_state == XLOG_STATE_SYNCING ||
2690               iclog->ic_state == XLOG_STATE_IOERROR);
2691        ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
2692        ASSERT(iclog->ic_bwritecnt == 1 || iclog->ic_bwritecnt == 2);
2693
2694
2695        /*
2696         * If we got an error, either on the first buffer, or in the case of
2697         * split log writes, on the second, we mark ALL iclogs STATE_IOERROR,
2698         * and none should ever be attempted to be written to disk
2699         * again.
2700         */
2701        if (iclog->ic_state != XLOG_STATE_IOERROR) {
2702                if (--iclog->ic_bwritecnt == 1) {
2703                        spin_unlock(&log->l_icloglock);
2704                        return;
2705                }
2706                iclog->ic_state = XLOG_STATE_DONE_SYNC;
2707        }
2708
2709        /*
2710         * Someone could be sleeping prior to writing out the next
2711         * iclog buffer, we wake them all, one will get to do the
2712         * I/O, the others get to wait for the result.
2713         */
2714        wake_up_all(&iclog->ic_write_wait);
2715        spin_unlock(&log->l_icloglock);
2716        xlog_state_do_callback(log, aborted, iclog);    /* also cleans log */
2717}       /* xlog_state_done_syncing */
2718
2719
2720/*
2721 * If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
2722 * sleep.  We wait on the flush queue on the head iclog as that should be
2723 * the first iclog to complete flushing. Hence if all iclogs are syncing,
2724 * we will wait here and all new writes will sleep until a sync completes.
2725 *
2726 * The in-core logs are used in a circular fashion. They are not used
2727 * out-of-order even when an iclog past the head is free.
2728 *
2729 * return:
2730 *      * log_offset where xlog_write() can start writing into the in-core
2731 *              log's data space.
2732 *      * in-core log pointer to which xlog_write() should write.
2733 *      * boolean indicating this is a continued write to an in-core log.
2734 *              If this is the last write, then the in-core log's offset field
2735 *              needs to be incremented, depending on the amount of data which
2736 *              is copied.
2737 */
2738STATIC int
2739xlog_state_get_iclog_space(
2740        struct xlog             *log,
2741        int                     len,
2742        struct xlog_in_core     **iclogp,
2743        struct xlog_ticket      *ticket,
2744        int                     *continued_write,
2745        int                     *logoffsetp)
2746{
2747        int               log_offset;
2748        xlog_rec_header_t *head;
2749        xlog_in_core_t    *iclog;
2750        int               error;
2751
2752restart:
2753        spin_lock(&log->l_icloglock);
2754        if (XLOG_FORCED_SHUTDOWN(log)) {
2755                spin_unlock(&log->l_icloglock);
2756                return XFS_ERROR(EIO);
2757        }
2758
2759        iclog = log->l_iclog;
2760        if (iclog->ic_state != XLOG_STATE_ACTIVE) {
2761                XFS_STATS_INC(xs_log_noiclogs);
2762
2763                /* Wait for log writes to have flushed */
2764                xlog_wait(&log->l_flush_wait, &log->l_icloglock);
2765                goto restart;
2766        }
2767
2768        head = &iclog->ic_header;
2769
2770        atomic_inc(&iclog->ic_refcnt);  /* prevents sync */
2771        log_offset = iclog->ic_offset;
2772
2773        /* On the 1st write to an iclog, figure out lsn.  This works
2774         * if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
2775         * committing to.  If the offset is set, that's how many blocks
2776         * must be written.
2777         */
2778        if (log_offset == 0) {
2779                ticket->t_curr_res -= log->l_iclog_hsize;
2780                xlog_tic_add_region(ticket,
2781                                    log->l_iclog_hsize,
2782                                    XLOG_REG_TYPE_LRHEADER);
2783                head->h_cycle = cpu_to_be32(log->l_curr_cycle);
2784                head->h_lsn = cpu_to_be64(
2785                        xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
2786                ASSERT(log->l_curr_block >= 0);
2787        }
2788
2789        /* If there is enough room to write everything, then do it.  Otherwise,
2790         * claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
2791         * bit is on, so this will get flushed out.  Don't update ic_offset
2792         * until you know exactly how many bytes get copied.  Therefore, wait
2793         * until later to update ic_offset.
2794         *
2795         * xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
2796         * can fit into remaining data section.
2797         */
2798        if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
2799                xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2800
2801                /*
2802                 * If I'm the only one writing to this iclog, sync it to disk.
2803                 * We need to do an atomic compare and decrement here to avoid
2804                 * racing with concurrent atomic_dec_and_lock() calls in
2805                 * xlog_state_release_iclog() when there is more than one
2806                 * reference to the iclog.
2807                 */
2808                if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1)) {
2809                        /* we are the only one */
2810                        spin_unlock(&log->l_icloglock);
2811                        error = xlog_state_release_iclog(log, iclog);
2812                        if (error)
2813                                return error;
2814                } else {
2815                        spin_unlock(&log->l_icloglock);
2816                }
2817                goto restart;
2818        }
2819
2820        /* Do we have enough room to write the full amount in the remainder
2821         * of this iclog?  Or must we continue a write on the next iclog and
2822         * mark this iclog as completely taken?  In the case where we switch
2823         * iclogs (to mark it taken), this particular iclog will release/sync
2824         * to disk in xlog_write().
2825         */
2826        if (len <= iclog->ic_size - iclog->ic_offset) {
2827                *continued_write = 0;
2828                iclog->ic_offset += len;
2829        } else {
2830                *continued_write = 1;
2831                xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
2832        }
2833        *iclogp = iclog;
2834
2835        ASSERT(iclog->ic_offset <= iclog->ic_size);
2836        spin_unlock(&log->l_icloglock);
2837
2838        *logoffsetp = log_offset;
2839        return 0;
2840}       /* xlog_state_get_iclog_space */
2841
2842/* The first cnt-1 times through here we don't need to
2843 * move the grant write head because the permanent
2844 * reservation has reserved cnt times the unit amount.
2845 * Release part of current permanent unit reservation and
2846 * reset current reservation to be one units worth.  Also
2847 * move grant reservation head forward.
2848 */
2849STATIC void
2850xlog_regrant_reserve_log_space(
2851        struct xlog             *log,
2852        struct xlog_ticket      *ticket)
2853{
2854        trace_xfs_log_regrant_reserve_enter(log, ticket);
2855
2856        if (ticket->t_cnt > 0)
2857                ticket->t_cnt--;
2858
2859        xlog_grant_sub_space(log, &log->l_reserve_head.grant,
2860                                        ticket->t_curr_res);
2861        xlog_grant_sub_space(log, &log->l_write_head.grant,
2862                                        ticket->t_curr_res);
2863        ticket->t_curr_res = ticket->t_unit_res;
2864        xlog_tic_reset_res(ticket);
2865
2866        trace_xfs_log_regrant_reserve_sub(log, ticket);
2867
2868        /* just return if we still have some of the pre-reserved space */
2869        if (ticket->t_cnt > 0)
2870                return;
2871
2872        xlog_grant_add_space(log, &log->l_reserve_head.grant,
2873                                        ticket->t_unit_res);
2874
2875        trace_xfs_log_regrant_reserve_exit(log, ticket);
2876
2877        ticket->t_curr_res = ticket->t_unit_res;
2878        xlog_tic_reset_res(ticket);
2879}       /* xlog_regrant_reserve_log_space */
2880
2881
2882/*
2883 * Give back the space left from a reservation.
2884 *
2885 * All the information we need to make a correct determination of space left
2886 * is present.  For non-permanent reservations, things are quite easy.  The
2887 * count should have been decremented to zero.  We only need to deal with the
2888 * space remaining in the current reservation part of the ticket.  If the
2889 * ticket contains a permanent reservation, there may be left over space which
2890 * needs to be released.  A count of N means that N-1 refills of the current
2891 * reservation can be done before we need to ask for more space.  The first
2892 * one goes to fill up the first current reservation.  Once we run out of
2893 * space, the count will stay at zero and the only space remaining will be
2894 * in the current reservation field.
2895 */
2896STATIC void
2897xlog_ungrant_log_space(
2898        struct xlog             *log,
2899        struct xlog_ticket      *ticket)
2900{
2901        int     bytes;
2902
2903        if (ticket->t_cnt > 0)
2904                ticket->t_cnt--;
2905
2906        trace_xfs_log_ungrant_enter(log, ticket);
2907        trace_xfs_log_ungrant_sub(log, ticket);
2908
2909        /*
2910         * If this is a permanent reservation ticket, we may be able to free
2911         * up more space based on the remaining count.
2912         */
2913        bytes = ticket->t_curr_res;
2914        if (ticket->t_cnt > 0) {
2915                ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
2916                bytes += ticket->t_unit_res*ticket->t_cnt;
2917        }
2918
2919        xlog_grant_sub_space(log, &log->l_reserve_head.grant, bytes);
2920        xlog_grant_sub_space(log, &log->l_write_head.grant, bytes);
2921
2922        trace_xfs_log_ungrant_exit(log, ticket);
2923
2924        xfs_log_space_wake(log->l_mp);
2925}
2926
2927/*
2928 * Flush iclog to disk if this is the last reference to the given iclog and
2929 * the WANT_SYNC bit is set.
2930 *
2931 * When this function is entered, the iclog is not necessarily in the
2932 * WANT_SYNC state.  It may be sitting around waiting to get filled.
2933 *
2934 *
2935 */
2936STATIC int
2937xlog_state_release_iclog(
2938        struct xlog             *log,
2939        struct xlog_in_core     *iclog)
2940{
2941        int             sync = 0;       /* do we sync? */
2942
2943        if (iclog->ic_state & XLOG_STATE_IOERROR)
2944                return XFS_ERROR(EIO);
2945
2946        ASSERT(atomic_read(&iclog->ic_refcnt) > 0);
2947        if (!atomic_dec_and_lock(&iclog->ic_refcnt, &log->l_icloglock))
2948                return 0;
2949
2950        if (iclog->ic_state & XLOG_STATE_IOERROR) {
2951                spin_unlock(&log->l_icloglock);
2952                return XFS_ERROR(EIO);
2953        }
2954        ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE ||
2955               iclog->ic_state == XLOG_STATE_WANT_SYNC);
2956
2957        if (iclog->ic_state == XLOG_STATE_WANT_SYNC) {
2958                /* update tail before writing to iclog */
2959                xfs_lsn_t tail_lsn = xlog_assign_tail_lsn(log->l_mp);
2960                sync++;
2961                iclog->ic_state = XLOG_STATE_SYNCING;
2962                iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn);
2963                xlog_verify_tail_lsn(log, iclog, tail_lsn);
2964                /* cycle incremented when incrementing curr_block */
2965        }
2966        spin_unlock(&log->l_icloglock);
2967
2968        /*
2969         * We let the log lock go, so it's possible that we hit a log I/O
2970         * error or some other SHUTDOWN condition that marks the iclog
2971         * as XLOG_STATE_IOERROR before the bwrite. However, we know that
2972         * this iclog has consistent data, so we ignore IOERROR
2973         * flags after this point.
2974         */
2975        if (sync)
2976                return xlog_sync(log, iclog);
2977        return 0;
2978}       /* xlog_state_release_iclog */
2979
2980
2981/*
2982 * This routine will mark the current iclog in the ring as WANT_SYNC
2983 * and move the current iclog pointer to the next iclog in the ring.
2984 * When this routine is called from xlog_state_get_iclog_space(), the
2985 * exact size of the iclog has not yet been determined.  All we know is
2986 * that every data block.  We have run out of space in this log record.
2987 */
2988STATIC void
2989xlog_state_switch_iclogs(
2990        struct xlog             *log,
2991        struct xlog_in_core     *iclog,
2992        int                     eventual_size)
2993{
2994        ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
2995        if (!eventual_size)
2996                eventual_size = iclog->ic_offset;
2997        iclog->ic_state = XLOG_STATE_WANT_SYNC;
2998        iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
2999        log->l_prev_block = log->l_curr_block;
3000        log->l_prev_cycle = log->l_curr_cycle;
3001
3002        /* roll log?: ic_offset changed later */
3003        log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
3004
3005        /* Round up to next log-sunit */
3006        if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
3007            log->l_mp->m_sb.sb_logsunit > 1) {
3008                __uint32_t sunit_bb = BTOBB(log->l_mp->m_sb.sb_logsunit);
3009                log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
3010        }
3011
3012        if (log->l_curr_block >= log->l_logBBsize) {
3013                log->l_curr_cycle++;
3014                if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
3015                        log->l_curr_cycle++;
3016                log->l_curr_block -= log->l_logBBsize;
3017                ASSERT(log->l_curr_block >= 0);
3018        }
3019        ASSERT(iclog == log->l_iclog);
3020        log->l_iclog = iclog->ic_next;
3021}       /* xlog_state_switch_iclogs */
3022
3023/*
3024 * Write out all data in the in-core log as of this exact moment in time.
3025 *
3026 * Data may be written to the in-core log during this call.  However,
3027 * we don't guarantee this data will be written out.  A change from past
3028 * implementation means this routine will *not* write out zero length LRs.
3029 *
3030 * Basically, we try and perform an intelligent scan of the in-core logs.
3031 * If we determine there is no flushable data, we just return.  There is no
3032 * flushable data if:
3033 *
3034 *      1. the current iclog is active and has no data; the previous iclog
3035 *              is in the active or dirty state.
3036 *      2. the current iclog is drity, and the previous iclog is in the
3037 *              active or dirty state.
3038 *
3039 * We may sleep if:
3040 *
3041 *      1. the current iclog is not in the active nor dirty state.
3042 *      2. the current iclog dirty, and the previous iclog is not in the
3043 *              active nor dirty state.
3044 *      3. the current iclog is active, and there is another thread writing
3045 *              to this particular iclog.
3046 *      4. a) the current iclog is active and has no other writers
3047 *         b) when we return from flushing out this iclog, it is still
3048 *              not in the active nor dirty state.
3049 */
3050int
3051_xfs_log_force(
3052        struct xfs_mount        *mp,
3053        uint                    flags,
3054        int                     *log_flushed)
3055{
3056        struct xlog             *log = mp->m_log;
3057        struct xlog_in_core     *iclog;
3058        xfs_lsn_t               lsn;
3059
3060        XFS_STATS_INC(xs_log_force);
3061
3062        xlog_cil_force(log);
3063
3064        spin_lock(&log->l_icloglock);
3065
3066        iclog = log->l_iclog;
3067        if (iclog->ic_state & XLOG_STATE_IOERROR) {
3068                spin_unlock(&log->l_icloglock);
3069                return XFS_ERROR(EIO);
3070        }
3071
3072        /* If the head iclog is not active nor dirty, we just attach
3073         * ourselves to the head and go to sleep.
3074         */
3075        if (iclog->ic_state == XLOG_STATE_ACTIVE ||
3076            iclog->ic_state == XLOG_STATE_DIRTY) {
3077                /*
3078                 * If the head is dirty or (active and empty), then
3079                 * we need to look at the previous iclog.  If the previous
3080                 * iclog is active or dirty we are done.  There is nothing
3081                 * to sync out.  Otherwise, we attach ourselves to the
3082                 * previous iclog and go to sleep.
3083                 */
3084                if (iclog->ic_state == XLOG_STATE_DIRTY ||
3085                    (atomic_read(&iclog->ic_refcnt) == 0
3086                     && iclog->ic_offset == 0)) {
3087                        iclog = iclog->ic_prev;
3088                        if (iclog->ic_state == XLOG_STATE_ACTIVE ||
3089                            iclog->ic_state == XLOG_STATE_DIRTY)
3090                                goto no_sleep;
3091                        else
3092                                goto maybe_sleep;
3093                } else {
3094                        if (atomic_read(&iclog->ic_refcnt) == 0) {
3095                                /* We are the only one with access to this
3096                                 * iclog.  Flush it out now.  There should
3097                                 * be a roundoff of zero to show that someone
3098                                 * has already taken care of the roundoff from
3099                                 * the previous sync.
3100                                 */
3101                                atomic_inc(&iclog->ic_refcnt);
3102                                lsn = be64_to_cpu(iclog->ic_header.h_lsn);
3103                                xlog_state_switch_iclogs(log, iclog, 0);
3104                                spin_unlock(&log->l_icloglock);
3105
3106                                if (xlog_state_release_iclog(log, iclog))
3107                                        return XFS_ERROR(EIO);
3108
3109                                if (log_flushed)
3110                                        *log_flushed = 1;
3111                                spin_lock(&log->l_icloglock);
3112                                if (be64_to_cpu(iclog->ic_header.h_lsn) == lsn &&
3113                                    iclog->ic_state != XLOG_STATE_DIRTY)
3114                                        goto maybe_sleep;
3115                                else
3116                                        goto no_sleep;
3117                        } else {
3118                                /* Someone else is writing to this iclog.
3119                                 * Use its call to flush out the data.  However,
3120                                 * the other thread may not force out this LR,
3121                                 * so we mark it WANT_SYNC.
3122                                 */
3123                                xlog_state_switch_iclogs(log, iclog, 0);
3124                                goto maybe_sleep;
3125                        }
3126                }
3127        }
3128
3129        /* By the time we come around again, the iclog could've been filled
3130         * which would give it another lsn.  If we have a new lsn, just
3131         * return because the relevant data has been flushed.
3132         */
3133maybe_sleep:
3134        if (flags & XFS_LOG_SYNC) {
3135                /*
3136                 * We must check if we're shutting down here, before
3137                 * we wait, while we're holding the l_icloglock.
3138                 * Then we check again after waking up, in case our
3139                 * sleep was disturbed by a bad news.
3140                 */
3141                if (iclog->ic_state & XLOG_STATE_IOERROR) {
3142                        spin_unlock(&log->l_icloglock);
3143                        return XFS_ERROR(EIO);
3144                }
3145                XFS_STATS_INC(xs_log_force_sleep);
3146                xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
3147                /*
3148                 * No need to grab the log lock here since we're
3149                 * only deciding whether or not to return EIO
3150                 * and the memory read should be atomic.
3151                 */
3152                if (iclog->ic_state & XLOG_STATE_IOERROR)
3153                        return XFS_ERROR(EIO);
3154                if (log_flushed)
3155                        *log_flushed = 1;
3156        } else {
3157
3158no_sleep:
3159                spin_unlock(&log->l_icloglock);
3160        }
3161        return 0;
3162}
3163
3164/*
3165 * Wrapper for _xfs_log_force(), to be used when caller doesn't care
3166 * about errors or whether the log was flushed or not. This is the normal
3167 * interface to use when trying to unpin items or move the log forward.
3168 */
3169void
3170xfs_log_force(
3171        xfs_mount_t     *mp,
3172        uint            flags)
3173{
3174        int     error;
3175
3176        trace_xfs_log_force(mp, 0);
3177        error = _xfs_log_force(mp, flags, NULL);
3178        if (error)
3179                xfs_warn(mp, "%s: error %d returned.", __func__, error);
3180}
3181
3182/*
3183 * Force the in-core log to disk for a specific LSN.
3184 *
3185 * Find in-core log with lsn.
3186 *      If it is in the DIRTY state, just return.
3187 *      If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
3188 *              state and go to sleep or return.
3189 *      If it is in any other state, go to sleep or return.
3190 *
3191 * Synchronous forces are implemented with a signal variable. All callers
3192 * to force a given lsn to disk will wait on a the sv attached to the
3193 * specific in-core log.  When given in-core log finally completes its
3194 * write to disk, that thread will wake up all threads waiting on the
3195 * sv.
3196 */
3197int
3198_xfs_log_force_lsn(
3199        struct xfs_mount        *mp,
3200        xfs_lsn_t               lsn,
3201        uint                    flags,
3202        int                     *log_flushed)
3203{
3204        struct xlog             *log = mp->m_log;
3205        struct xlog_in_core     *iclog;
3206        int                     already_slept = 0;
3207
3208        ASSERT(lsn != 0);
3209
3210        XFS_STATS_INC(xs_log_force);
3211
3212        lsn = xlog_cil_force_lsn(log, lsn);
3213        if (lsn == NULLCOMMITLSN)
3214                return 0;
3215
3216try_again:
3217        spin_lock(&log->l_icloglock);
3218        iclog = log->l_iclog;
3219        if (iclog->ic_state & XLOG_STATE_IOERROR) {
3220                spin_unlock(&log->l_icloglock);
3221                return XFS_ERROR(EIO);
3222        }
3223
3224        do {
3225                if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
3226                        iclog = iclog->ic_next;
3227                        continue;
3228                }
3229
3230                if (iclog->ic_state == XLOG_STATE_DIRTY) {
3231                        spin_unlock(&log->l_icloglock);
3232                        return 0;
3233                }
3234
3235                if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3236                        /*
3237                         * We sleep here if we haven't already slept (e.g.
3238                         * this is the first time we've looked at the correct
3239                         * iclog buf) and the buffer before us is going to
3240                         * be sync'ed. The reason for this is that if we
3241                         * are doing sync transactions here, by waiting for
3242                         * the previous I/O to complete, we can allow a few
3243                         * more transactions into this iclog before we close
3244                         * it down.
3245                         *
3246                         * Otherwise, we mark the buffer WANT_SYNC, and bump
3247                         * up the refcnt so we can release the log (which
3248                         * drops the ref count).  The state switch keeps new
3249                         * transaction commits from using this buffer.  When
3250                         * the current commits finish writing into the buffer,
3251                         * the refcount will drop to zero and the buffer will
3252                         * go out then.
3253                         */
3254                        if (!already_slept &&
3255                            (iclog->ic_prev->ic_state &
3256                             (XLOG_STATE_WANT_SYNC | XLOG_STATE_SYNCING))) {
3257                                ASSERT(!(iclog->ic_state & XLOG_STATE_IOERROR));
3258
3259                                XFS_STATS_INC(xs_log_force_sleep);
3260
3261                                xlog_wait(&iclog->ic_prev->ic_write_wait,
3262                                                        &log->l_icloglock);
3263                                if (log_flushed)
3264                                        *log_flushed = 1;
3265                                already_slept = 1;
3266                                goto try_again;
3267                        }
3268                        atomic_inc(&iclog->ic_refcnt);
3269                        xlog_state_switch_iclogs(log, iclog, 0);
3270                        spin_unlock(&log->l_icloglock);
3271                        if (xlog_state_release_iclog(log, iclog))
3272                                return XFS_ERROR(EIO);
3273                        if (log_flushed)
3274                                *log_flushed = 1;
3275                        spin_lock(&log->l_icloglock);
3276                }
3277
3278                if ((flags & XFS_LOG_SYNC) && /* sleep */
3279                    !(iclog->ic_state &
3280                      (XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY))) {
3281                        /*
3282                         * Don't wait on completion if we know that we've
3283                         * gotten a log write error.
3284                         */
3285                        if (iclog->ic_state & XLOG_STATE_IOERROR) {
3286                                spin_unlock(&log->l_icloglock);
3287                                return XFS_ERROR(EIO);
3288                        }
3289                        XFS_STATS_INC(xs_log_force_sleep);
3290                        xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
3291                        /*
3292                         * No need to grab the log lock here since we're
3293                         * only deciding whether or not to return EIO
3294                         * and the memory read should be atomic.
3295                         */
3296                        if (iclog->ic_state & XLOG_STATE_IOERROR)
3297                                return XFS_ERROR(EIO);
3298
3299                        if (log_flushed)
3300                                *log_flushed = 1;
3301                } else {                /* just return */
3302                        spin_unlock(&log->l_icloglock);
3303                }
3304
3305                return 0;
3306        } while (iclog != log->l_iclog);
3307
3308        spin_unlock(&log->l_icloglock);
3309        return 0;
3310}
3311
3312/*
3313 * Wrapper for _xfs_log_force_lsn(), to be used when caller doesn't care
3314 * about errors or whether the log was flushed or not. This is the normal
3315 * interface to use when trying to unpin items or move the log forward.
3316 */
3317void
3318xfs_log_force_lsn(
3319        xfs_mount_t     *mp,
3320        xfs_lsn_t       lsn,
3321        uint            flags)
3322{
3323        int     error;
3324
3325        trace_xfs_log_force(mp, lsn);
3326        error = _xfs_log_force_lsn(mp, lsn, flags, NULL);
3327        if (error)
3328                xfs_warn(mp, "%s: error %d returned.", __func__, error);
3329}
3330
3331/*
3332 * Called when we want to mark the current iclog as being ready to sync to
3333 * disk.
3334 */
3335STATIC void
3336xlog_state_want_sync(
3337        struct xlog             *log,
3338        struct xlog_in_core     *iclog)
3339{
3340        assert_spin_locked(&log->l_icloglock);
3341
3342        if (iclog->ic_state == XLOG_STATE_ACTIVE) {
3343                xlog_state_switch_iclogs(log, iclog, 0);
3344        } else {
3345                ASSERT(iclog->ic_state &
3346                        (XLOG_STATE_WANT_SYNC|XLOG_STATE_IOERROR));
3347        }
3348}
3349
3350
3351/*****************************************************************************
3352 *
3353 *              TICKET functions
3354 *
3355 *****************************************************************************
3356 */
3357
3358/*
3359 * Free a used ticket when its refcount falls to zero.
3360 */
3361void
3362xfs_log_ticket_put(
3363        xlog_ticket_t   *ticket)
3364{
3365        ASSERT(atomic_read(&ticket->t_ref) > 0);
3366        if (atomic_dec_and_test(&ticket->t_ref))
3367                kmem_zone_free(xfs_log_ticket_zone, ticket);
3368}
3369
3370xlog_ticket_t *
3371xfs_log_ticket_get(
3372        xlog_ticket_t   *ticket)
3373{
3374        ASSERT(atomic_read(&ticket->t_ref) > 0);
3375        atomic_inc(&ticket->t_ref);
3376        return ticket;
3377}
3378
3379/*
3380 * Allocate and initialise a new log ticket.
3381 */
3382struct xlog_ticket *
3383xlog_ticket_alloc(
3384        struct xlog     *log,
3385        int             unit_bytes,
3386        int             cnt,
3387        char            client,
3388        bool            permanent,
3389        xfs_km_flags_t  alloc_flags)
3390{
3391        struct xlog_ticket *tic;
3392        uint            num_headers;
3393        int             iclog_space;
3394
3395        tic = kmem_zone_zalloc(xfs_log_ticket_zone, alloc_flags);
3396        if (!tic)
3397                return NULL;
3398
3399        /*
3400         * Permanent reservations have up to 'cnt'-1 active log operations
3401         * in the log.  A unit in this case is the amount of space for one
3402         * of these log operations.  Normal reservations have a cnt of 1
3403         * and their unit amount is the total amount of space required.
3404         *
3405         * The following lines of code account for non-transaction data
3406         * which occupy space in the on-disk log.
3407         *
3408         * Normal form of a transaction is:
3409         * <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
3410         * and then there are LR hdrs, split-recs and roundoff at end of syncs.
3411         *
3412         * We need to account for all the leadup data and trailer data
3413         * around the transaction data.
3414         * And then we need to account for the worst case in terms of using
3415         * more space.
3416         * The worst case will happen if:
3417         * - the placement of the transaction happens to be such that the
3418         *   roundoff is at its maximum
3419         * - the transaction data is synced before the commit record is synced
3420         *   i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
3421         *   Therefore the commit record is in its own Log Record.
3422         *   This can happen as the commit record is called with its
3423         *   own region to xlog_write().
3424         *   This then means that in the worst case, roundoff can happen for
3425         *   the commit-rec as well.
3426         *   The commit-rec is smaller than padding in this scenario and so it is
3427         *   not added separately.
3428         */
3429
3430        /* for trans header */
3431        unit_bytes += sizeof(xlog_op_header_t);
3432        unit_bytes += sizeof(xfs_trans_header_t);
3433
3434        /* for start-rec */
3435        unit_bytes += sizeof(xlog_op_header_t);
3436
3437        /*
3438         * for LR headers - the space for data in an iclog is the size minus
3439         * the space used for the headers. If we use the iclog size, then we
3440         * undercalculate the number of headers required.
3441         *
3442         * Furthermore - the addition of op headers for split-recs might
3443         * increase the space required enough to require more log and op
3444         * headers, so take that into account too.
3445         *
3446         * IMPORTANT: This reservation makes the assumption that if this
3447         * transaction is the first in an iclog and hence has the LR headers
3448         * accounted to it, then the remaining space in the iclog is
3449         * exclusively for this transaction.  i.e. if the transaction is larger
3450         * than the iclog, it will be the only thing in that iclog.
3451         * Fundamentally, this means we must pass the entire log vector to
3452         * xlog_write to guarantee this.
3453         */
3454        iclog_space = log->l_iclog_size - log->l_iclog_hsize;
3455        num_headers = howmany(unit_bytes, iclog_space);
3456
3457        /* for split-recs - ophdrs added when data split over LRs */
3458        unit_bytes += sizeof(xlog_op_header_t) * num_headers;
3459
3460        /* add extra header reservations if we overrun */
3461        while (!num_headers ||
3462               howmany(unit_bytes, iclog_space) > num_headers) {
3463                unit_bytes += sizeof(xlog_op_header_t);
3464                num_headers++;
3465        }
3466        unit_bytes += log->l_iclog_hsize * num_headers;
3467
3468        /* for commit-rec LR header - note: padding will subsume the ophdr */
3469        unit_bytes += log->l_iclog_hsize;
3470
3471        /* for roundoff padding for transaction data and one for commit record */
3472        if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
3473            log->l_mp->m_sb.sb_logsunit > 1) {
3474                /* log su roundoff */
3475                unit_bytes += 2*log->l_mp->m_sb.sb_logsunit;
3476        } else {
3477                /* BB roundoff */
3478                unit_bytes += 2*BBSIZE;
3479        }
3480
3481        atomic_set(&tic->t_ref, 1);
3482        tic->t_task             = current;
3483        INIT_LIST_HEAD(&tic->t_queue);
3484        tic->t_unit_res         = unit_bytes;
3485        tic->t_curr_res         = unit_bytes;
3486        tic->t_cnt              = cnt;
3487        tic->t_ocnt             = cnt;
3488        tic->t_tid              = random32();
3489        tic->t_clientid         = client;
3490        tic->t_flags            = XLOG_TIC_INITED;
3491        tic->t_trans_type       = 0;
3492        if (permanent)
3493                tic->t_flags |= XLOG_TIC_PERM_RESERV;
3494
3495        xlog_tic_reset_res(tic);
3496
3497        return tic;
3498}
3499
3500
3501/******************************************************************************
3502 *
3503 *              Log debug routines
3504 *
3505 ******************************************************************************
3506 */
3507#if defined(DEBUG)
3508/*
3509 * Make sure that the destination ptr is within the valid data region of
3510 * one of the iclogs.  This uses backup pointers stored in a different
3511 * part of the log in case we trash the log structure.
3512 */
3513void
3514xlog_verify_dest_ptr(
3515        struct xlog     *log,
3516        char            *ptr)
3517{
3518        int i;
3519        int good_ptr = 0;
3520
3521        for (i = 0; i < log->l_iclog_bufs; i++) {
3522                if (ptr >= log->l_iclog_bak[i] &&
3523                    ptr <= log->l_iclog_bak[i] + log->l_iclog_size)
3524                        good_ptr++;
3525        }
3526
3527        if (!good_ptr)
3528                xfs_emerg(log->l_mp, "%s: invalid ptr", __func__);
3529}
3530
3531/*
3532 * Check to make sure the grant write head didn't just over lap the tail.  If
3533 * the cycles are the same, we can't be overlapping.  Otherwise, make sure that
3534 * the cycles differ by exactly one and check the byte count.
3535 *
3536 * This check is run unlocked, so can give false positives. Rather than assert
3537 * on failures, use a warn-once flag and a panic tag to allow the admin to
3538 * determine if they want to panic the machine when such an error occurs. For
3539 * debug kernels this will have the same effect as using an assert but, unlinke
3540 * an assert, it can be turned off at runtime.
3541 */
3542STATIC void
3543xlog_verify_grant_tail(
3544        struct xlog     *log)
3545{
3546        int             tail_cycle, tail_blocks;
3547        int             cycle, space;
3548
3549        xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &space);
3550        xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
3551        if (tail_cycle != cycle) {
3552                if (cycle - 1 != tail_cycle &&
3553                    !(log->l_flags & XLOG_TAIL_WARN)) {
3554                        xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3555                                "%s: cycle - 1 != tail_cycle", __func__);
3556                        log->l_flags |= XLOG_TAIL_WARN;
3557                }
3558
3559                if (space > BBTOB(tail_blocks) &&
3560                    !(log->l_flags & XLOG_TAIL_WARN)) {
3561                        xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
3562                                "%s: space > BBTOB(tail_blocks)", __func__);
3563                        log->l_flags |= XLOG_TAIL_WARN;
3564                }
3565        }
3566}
3567
3568/* check if it will fit */
3569STATIC void
3570xlog_verify_tail_lsn(
3571        struct xlog             *log,
3572        struct xlog_in_core     *iclog,
3573        xfs_lsn_t               tail_lsn)
3574{
3575    int blocks;
3576
3577    if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
3578        blocks =
3579            log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
3580        if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
3581                xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3582    } else {
3583        ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
3584
3585        if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
3586                xfs_emerg(log->l_mp, "%s: tail wrapped", __func__);
3587
3588        blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
3589        if (blocks < BTOBB(iclog->ic_offset) + 1)
3590                xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
3591    }
3592}       /* xlog_verify_tail_lsn */
3593
3594/*
3595 * Perform a number of checks on the iclog before writing to disk.
3596 *
3597 * 1. Make sure the iclogs are still circular
3598 * 2. Make sure we have a good magic number
3599 * 3. Make sure we don't have magic numbers in the data
3600 * 4. Check fields of each log operation header for:
3601 *      A. Valid client identifier
3602 *      B. tid ptr value falls in valid ptr space (user space code)
3603 *      C. Length in log record header is correct according to the
3604 *              individual operation headers within record.
3605 * 5. When a bwrite will occur within 5 blocks of the front of the physical
3606 *      log, check the preceding blocks of the physical log to make sure all
3607 *      the cycle numbers agree with the current cycle number.
3608 */
3609STATIC void
3610xlog_verify_iclog(
3611        struct xlog             *log,
3612        struct xlog_in_core     *iclog,
3613        int                     count,
3614        boolean_t               syncing)
3615{
3616        xlog_op_header_t        *ophead;
3617        xlog_in_core_t          *icptr;
3618        xlog_in_core_2_t        *xhdr;
3619        xfs_caddr_t             ptr;
3620        xfs_caddr_t             base_ptr;
3621        __psint_t               field_offset;
3622        __uint8_t               clientid;
3623        int                     len, i, j, k, op_len;
3624        int                     idx;
3625
3626        /* check validity of iclog pointers */
3627        spin_lock(&log->l_icloglock);
3628        icptr = log->l_iclog;
3629        for (i=0; i < log->l_iclog_bufs; i++) {
3630                if (icptr == NULL)
3631                        xfs_emerg(log->l_mp, "%s: invalid ptr", __func__);
3632                icptr = icptr->ic_next;
3633        }
3634        if (icptr != log->l_iclog)
3635                xfs_emerg(log->l_mp, "%s: corrupt iclog ring", __func__);
3636        spin_unlock(&log->l_icloglock);
3637
3638        /* check log magic numbers */
3639        if (iclog->ic_header.h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3640                xfs_emerg(log->l_mp, "%s: invalid magic num", __func__);
3641
3642        ptr = (xfs_caddr_t) &iclog->ic_header;
3643        for (ptr += BBSIZE; ptr < ((xfs_caddr_t)&iclog->ic_header) + count;
3644             ptr += BBSIZE) {
3645                if (*(__be32 *)ptr == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
3646                        xfs_emerg(log->l_mp, "%s: unexpected magic num",
3647                                __func__);
3648        }
3649
3650        /* check fields */
3651        len = be32_to_cpu(iclog->ic_header.h_num_logops);
3652        ptr = iclog->ic_datap;
3653        base_ptr = ptr;
3654        ophead = (xlog_op_header_t *)ptr;
3655        xhdr = iclog->ic_data;
3656        for (i = 0; i < len; i++) {
3657                ophead = (xlog_op_header_t *)ptr;
3658
3659                /* clientid is only 1 byte */
3660                field_offset = (__psint_t)
3661                               ((xfs_caddr_t)&(ophead->oh_clientid) - base_ptr);
3662                if (syncing == B_FALSE || (field_offset & 0x1ff)) {
3663                        clientid = ophead->oh_clientid;
3664                } else {
3665                        idx = BTOBBT((xfs_caddr_t)&(ophead->oh_clientid) - iclog->ic_datap);
3666                        if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3667                                j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3668                                k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3669                                clientid = xlog_get_client_id(
3670                                        xhdr[j].hic_xheader.xh_cycle_data[k]);
3671                        } else {
3672                                clientid = xlog_get_client_id(
3673                                        iclog->ic_header.h_cycle_data[idx]);
3674                        }
3675                }
3676                if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
3677                        xfs_warn(log->l_mp,
3678                                "%s: invalid clientid %d op 0x%p offset 0x%lx",
3679                                __func__, clientid, ophead,
3680                                (unsigned long)field_offset);
3681
3682                /* check length */
3683                field_offset = (__psint_t)
3684                               ((xfs_caddr_t)&(ophead->oh_len) - base_ptr);
3685                if (syncing == B_FALSE || (field_offset & 0x1ff)) {
3686                        op_len = be32_to_cpu(ophead->oh_len);
3687                } else {
3688                        idx = BTOBBT((__psint_t)&ophead->oh_len -
3689                                    (__psint_t)iclog->ic_datap);
3690                        if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
3691                                j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3692                                k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3693                                op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
3694                        } else {
3695                                op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
3696                        }
3697                }
3698                ptr += sizeof(xlog_op_header_t) + op_len;
3699        }
3700}       /* xlog_verify_iclog */
3701#endif
3702
3703/*
3704 * Mark all iclogs IOERROR. l_icloglock is held by the caller.
3705 */
3706STATIC int
3707xlog_state_ioerror(
3708        struct xlog     *log)
3709{
3710        xlog_in_core_t  *iclog, *ic;
3711
3712        iclog = log->l_iclog;
3713        if (! (iclog->ic_state & XLOG_STATE_IOERROR)) {
3714                /*
3715                 * Mark all the incore logs IOERROR.
3716                 * From now on, no log flushes will result.
3717                 */
3718                ic = iclog;
3719                do {
3720                        ic->ic_state = XLOG_STATE_IOERROR;
3721                        ic = ic->ic_next;
3722                } while (ic != iclog);
3723                return 0;
3724        }
3725        /*
3726         * Return non-zero, if state transition has already happened.
3727         */
3728        return 1;
3729}
3730
3731/*
3732 * This is called from xfs_force_shutdown, when we're forcibly
3733 * shutting down the filesystem, typically because of an IO error.
3734 * Our main objectives here are to make sure that:
3735 *      a. the filesystem gets marked 'SHUTDOWN' for all interested
3736 *         parties to find out, 'atomically'.
3737 *      b. those who're sleeping on log reservations, pinned objects and
3738 *          other resources get woken up, and be told the bad news.
3739 *      c. nothing new gets queued up after (a) and (b) are done.
3740 *      d. if !logerror, flush the iclogs to disk, then seal them off
3741 *         for business.
3742 *
3743 * Note: for delayed logging the !logerror case needs to flush the regions
3744 * held in memory out to the iclogs before flushing them to disk. This needs
3745 * to be done before the log is marked as shutdown, otherwise the flush to the
3746 * iclogs will fail.
3747 */
3748int
3749xfs_log_force_umount(
3750        struct xfs_mount        *mp,
3751        int                     logerror)
3752{
3753        struct xlog     *log;
3754        int             retval;
3755
3756        log = mp->m_log;
3757
3758        /*
3759         * If this happens during log recovery, don't worry about
3760         * locking; the log isn't open for business yet.
3761         */
3762        if (!log ||
3763            log->l_flags & XLOG_ACTIVE_RECOVERY) {
3764                mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3765                if (mp->m_sb_bp)
3766                        XFS_BUF_DONE(mp->m_sb_bp);
3767                return 0;
3768        }
3769
3770        /*
3771         * Somebody could've already done the hard work for us.
3772         * No need to get locks for this.
3773         */
3774        if (logerror && log->l_iclog->ic_state & XLOG_STATE_IOERROR) {
3775                ASSERT(XLOG_FORCED_SHUTDOWN(log));
3776                return 1;
3777        }
3778        retval = 0;
3779
3780        /*
3781         * Flush the in memory commit item list before marking the log as
3782         * being shut down. We need to do it in this order to ensure all the
3783         * completed transactions are flushed to disk with the xfs_log_force()
3784         * call below.
3785         */
3786        if (!logerror)
3787                xlog_cil_force(log);
3788
3789        /*
3790         * mark the filesystem and the as in a shutdown state and wake
3791         * everybody up to tell them the bad news.
3792         */
3793        spin_lock(&log->l_icloglock);
3794        mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
3795        if (mp->m_sb_bp)
3796                XFS_BUF_DONE(mp->m_sb_bp);
3797
3798        /*
3799         * This flag is sort of redundant because of the mount flag, but
3800         * it's good to maintain the separation between the log and the rest
3801         * of XFS.
3802         */
3803        log->l_flags |= XLOG_IO_ERROR;
3804
3805        /*
3806         * If we hit a log error, we want to mark all the iclogs IOERROR
3807         * while we're still holding the loglock.
3808         */
3809        if (logerror)
3810                retval = xlog_state_ioerror(log);
3811        spin_unlock(&log->l_icloglock);
3812
3813        /*
3814         * We don't want anybody waiting for log reservations after this. That
3815         * means we have to wake up everybody queued up on reserveq as well as
3816         * writeq.  In addition, we make sure in xlog_{re}grant_log_space that
3817         * we don't enqueue anything once the SHUTDOWN flag is set, and this
3818         * action is protected by the grant locks.
3819         */
3820        xlog_grant_head_wake_all(&log->l_reserve_head);
3821        xlog_grant_head_wake_all(&log->l_write_head);
3822
3823        if (!(log->l_iclog->ic_state & XLOG_STATE_IOERROR)) {
3824                ASSERT(!logerror);
3825                /*
3826                 * Force the incore logs to disk before shutting the
3827                 * log down completely.
3828                 */
3829                _xfs_log_force(mp, XFS_LOG_SYNC, NULL);
3830
3831                spin_lock(&log->l_icloglock);
3832                retval = xlog_state_ioerror(log);
3833                spin_unlock(&log->l_icloglock);
3834        }
3835        /*
3836         * Wake up everybody waiting on xfs_log_force.
3837         * Callback all log item committed functions as if the
3838         * log writes were completed.
3839         */
3840        xlog_state_do_callback(log, XFS_LI_ABORTED, NULL);
3841
3842#ifdef XFSERRORDEBUG
3843        {
3844                xlog_in_core_t  *iclog;
3845
3846                spin_lock(&log->l_icloglock);
3847                iclog = log->l_iclog;
3848                do {
3849                        ASSERT(iclog->ic_callback == 0);
3850                        iclog = iclog->ic_next;
3851                } while (iclog != log->l_iclog);
3852                spin_unlock(&log->l_icloglock);
3853        }
3854#endif
3855        /* return non-zero if log IOERROR transition had already happened */
3856        return retval;
3857}
3858
3859STATIC int
3860xlog_iclogs_empty(
3861        struct xlog     *log)
3862{
3863        xlog_in_core_t  *iclog;
3864
3865        iclog = log->l_iclog;
3866        do {
3867                /* endianness does not matter here, zero is zero in
3868                 * any language.
3869                 */
3870                if (iclog->ic_header.h_num_logops)
3871                        return 0;
3872                iclog = iclog->ic_next;
3873        } while (iclog != log->l_iclog);
3874        return 1;
3875}
3876
3877
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