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