fs/xfs/xfs_log.c

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