err.no Git - linux-2.6/blob - fs/gfs2/log.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License v.2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <asm/semaphore.h>
  16
  17 #include "gfs2.h"
  18 #include "bmap.h"
  19 #include "glock.h"
  20 #include "log.h"
  21 #include "lops.h"
  22 #include "meta_io.h"
  23
  24 #define PULL 1
  25
  26 static inline int is_done(struct gfs2_sbd *sdp, atomic_t *a)
  27 {
  28         int done;
  29         gfs2_log_lock(sdp);
  30         done = atomic_read(a) ? 0 : 1;
  31         gfs2_log_unlock(sdp);
  32         return done;
  33 }
  34
  35 static void do_lock_wait(struct gfs2_sbd *sdp, wait_queue_head_t *wq,
  36                          atomic_t *a)
  37 {
  38         gfs2_log_unlock(sdp);
  39         wait_event(*wq, is_done(sdp, a));
  40         gfs2_log_lock(sdp);
  41 }
  42
  43 static void lock_for_trans(struct gfs2_sbd *sdp)
  44 {
  45         gfs2_log_lock(sdp);
  46         do_lock_wait(sdp, &sdp->sd_log_trans_wq, &sdp->sd_log_flush_count);
  47         atomic_inc(&sdp->sd_log_trans_count);
  48         gfs2_log_unlock(sdp);
  49 }
  50
  51 static void unlock_from_trans(struct gfs2_sbd *sdp)
  52 {
  53         gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_trans_count));
  54         if (atomic_dec_and_test(&sdp->sd_log_trans_count))
  55                 wake_up(&sdp->sd_log_flush_wq);
  56 }
  57
  58 void gfs2_lock_for_flush(struct gfs2_sbd *sdp)
  59 {
  60         gfs2_log_lock(sdp);
  61         atomic_inc(&sdp->sd_log_flush_count);
  62         do_lock_wait(sdp, &sdp->sd_log_flush_wq, &sdp->sd_log_trans_count);
  63         gfs2_log_unlock(sdp);
  64 }
  65
  66 void gfs2_unlock_from_flush(struct gfs2_sbd *sdp)
  67 {
  68         gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_flush_count));
  69         if (atomic_dec_and_test(&sdp->sd_log_flush_count))
  70                 wake_up(&sdp->sd_log_trans_wq);
  71 }
  72
  73 /**
  74  * gfs2_struct2blk - compute stuff
  75  * @sdp: the filesystem
  76  * @nstruct: the number of structures
  77  * @ssize: the size of the structures
  78  *
  79  * Compute the number of log descriptor blocks needed to hold a certain number
  80  * of structures of a certain size.
  81  *
  82  * Returns: the number of blocks needed (minimum is always 1)
  83  */
  84
  85 unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct,
  86                              unsigned int ssize)
  87 {
  88         unsigned int blks;
  89         unsigned int first, second;
  90
  91         blks = 1;
  92         first = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) / ssize;
  93
  94         if (nstruct > first) {
  95                 second = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header)) / ssize;
  96                 blks += DIV_RU(nstruct - first, second);
  97         }
  98
  99         return blks;
 100 }
 101
 102 void gfs2_ail1_start(struct gfs2_sbd *sdp, int flags)
 103 {
 104         struct list_head *head = &sdp->sd_ail1_list;
 105         uint64_t sync_gen;
 106         struct list_head *first, *tmp;
 107         struct gfs2_ail *first_ai, *ai;
 108
 109         gfs2_log_lock(sdp);
 110         if (list_empty(head)) {
 111                 gfs2_log_unlock(sdp);
 112                 return;
 113         }
 114         sync_gen = sdp->sd_ail_sync_gen++;
 115
 116         first = head->prev;
 117         first_ai = list_entry(first, struct gfs2_ail, ai_list);
 118         first_ai->ai_sync_gen = sync_gen;
 119         gfs2_ail1_start_one(sdp, first_ai);
 120
 121         if (flags & DIO_ALL)
 122                 first = NULL;
 123
 124         for (;;) {
 125                 if (first &&
 126                     (head->prev != first ||
 127                      gfs2_ail1_empty_one(sdp, first_ai, 0)))
 128                         break;
 129
 130                 for (tmp = head->prev; tmp != head; tmp = tmp->prev) {
 131                         ai = list_entry(tmp, struct gfs2_ail, ai_list);
 132                         if (ai->ai_sync_gen >= sync_gen)
 133                                 continue;
 134                         ai->ai_sync_gen = sync_gen;
 135                         gfs2_ail1_start_one(sdp, ai);
 136                         break;
 137                 }
 138
 139                 if (tmp == head)
 140                         break;
 141         }
 142
 143         gfs2_log_unlock(sdp);
 144 }
 145
 146 int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags)
 147 {
 148         struct gfs2_ail *ai, *s;
 149         int ret;
 150
 151         gfs2_log_lock(sdp);
 152
 153         list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) {
 154                 if (gfs2_ail1_empty_one(sdp, ai, flags))
 155                         list_move(&ai->ai_list, &sdp->sd_ail2_list);
 156                 else if (!(flags & DIO_ALL))
 157                         break;
 158         }
 159
 160         ret = list_empty(&sdp->sd_ail1_list);
 161
 162         gfs2_log_unlock(sdp);
 163
 164         return ret;
 165 }
 166
 167 static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
 168 {
 169         struct gfs2_ail *ai, *safe;
 170         unsigned int old_tail = sdp->sd_log_tail;
 171         int wrap = (new_tail < old_tail);
 172         int a, b, rm;
 173
 174         gfs2_log_lock(sdp);
 175
 176         list_for_each_entry_safe(ai, safe, &sdp->sd_ail2_list, ai_list) {
 177                 a = (old_tail <= ai->ai_first);
 178                 b = (ai->ai_first < new_tail);
 179                 rm = (wrap) ? (a || b) : (a && b);
 180                 if (!rm)
 181                         continue;
 182
 183                 gfs2_ail2_empty_one(sdp, ai);
 184                 list_del(&ai->ai_list);
 185                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail1_list));
 186                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail2_list));
 187                 kfree(ai);
 188         }
 189
 190         gfs2_log_unlock(sdp);
 191 }
 192
 193 /**
 194  * gfs2_log_reserve - Make a log reservation
 195  * @sdp: The GFS2 superblock
 196  * @blks: The number of blocks to reserve
 197  *
 198  * Returns: errno
 199  */
 200
 201 int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 202 {
 203         LIST_HEAD(list);
 204         unsigned int try = 0;
 205
 206         if (gfs2_assert_warn(sdp, blks) ||
 207             gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
 208                 return -EINVAL;
 209
 210         for (;;) {
 211                 gfs2_log_lock(sdp);
 212
 213                 if (list_empty(&list)) {
 214                         list_add_tail(&list, &sdp->sd_log_blks_list);
 215                         while (sdp->sd_log_blks_list.next != &list) {
 216                                 DECLARE_WAITQUEUE(__wait_chan, current);
 217                                 set_current_state(TASK_UNINTERRUPTIBLE);
 218                                 add_wait_queue(&sdp->sd_log_blks_wait,
 219                                                &__wait_chan);
 220                                 gfs2_log_unlock(sdp);
 221                                 schedule();
 222                                 gfs2_log_lock(sdp);
 223                                 remove_wait_queue(&sdp->sd_log_blks_wait,
 224                                                   &__wait_chan);
 225                                 set_current_state(TASK_RUNNING);
 226                         }
 227                 }
 228
 229                 /* Never give away the last block so we can
 230                    always pull the tail if we need to. */
 231                 if (sdp->sd_log_blks_free > blks) {
 232                         sdp->sd_log_blks_free -= blks;
 233                         list_del(&list);
 234                         gfs2_log_unlock(sdp);
 235                         wake_up(&sdp->sd_log_blks_wait);
 236                         break;
 237                 }
 238
 239                 gfs2_log_unlock(sdp);
 240
 241                 gfs2_ail1_empty(sdp, 0);
 242                 gfs2_log_flush(sdp);
 243
 244                 if (try++)
 245                         gfs2_ail1_start(sdp, 0);
 246         }
 247
 248         lock_for_trans(sdp);
 249
 250         return 0;
 251 }
 252
 253 /**
 254  * gfs2_log_release - Release a given number of log blocks
 255  * @sdp: The GFS2 superblock
 256  * @blks: The number of blocks
 257  *
 258  */
 259
 260 void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
 261 {
 262         unlock_from_trans(sdp);
 263
 264         gfs2_log_lock(sdp);
 265         sdp->sd_log_blks_free += blks;
 266         gfs2_assert_withdraw(sdp,
 267                              sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
 268         gfs2_log_unlock(sdp);
 269 }
 270
 271 static uint64_t log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
 272 {
 273         int new = 0;
 274         uint64_t dbn;
 275         int error;
 276
 277         error = gfs2_block_map(get_v2ip(sdp->sd_jdesc->jd_inode), lbn, &new, &dbn, NULL);
 278         gfs2_assert_withdraw(sdp, !error && dbn);
 279
 280         return dbn;
 281 }
 282
 283 /**
 284  * log_distance - Compute distance between two journal blocks
 285  * @sdp: The GFS2 superblock
 286  * @newer: The most recent journal block of the pair
 287  * @older: The older journal block of the pair
 288  *
 289  *   Compute the distance (in the journal direction) between two
 290  *   blocks in the journal
 291  *
 292  * Returns: the distance in blocks
 293  */
 294
 295 static inline unsigned int log_distance(struct gfs2_sbd *sdp,
 296                                         unsigned int newer,
 297                                         unsigned int older)
 298 {
 299         int dist;
 300
 301         dist = newer - older;
 302         if (dist < 0)
 303                 dist += sdp->sd_jdesc->jd_blocks;
 304
 305         return dist;
 306 }
 307
 308 static unsigned int current_tail(struct gfs2_sbd *sdp)
 309 {
 310         struct gfs2_ail *ai;
 311         unsigned int tail;
 312
 313         gfs2_log_lock(sdp);
 314
 315         if (list_empty(&sdp->sd_ail1_list))
 316                 tail = sdp->sd_log_head;
 317         else {
 318                 ai = list_entry(sdp->sd_ail1_list.prev,
 319                                 struct gfs2_ail, ai_list);
 320                 tail = ai->ai_first;
 321         }
 322
 323         gfs2_log_unlock(sdp);
 324
 325         return tail;
 326 }
 327
 328 static inline void log_incr_head(struct gfs2_sbd *sdp)
 329 {
 330         if (sdp->sd_log_flush_head == sdp->sd_log_tail)
 331                 gfs2_assert_withdraw(sdp,
 332                                 sdp->sd_log_flush_head == sdp->sd_log_head);
 333
 334         if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
 335                 sdp->sd_log_flush_head = 0;
 336                 sdp->sd_log_flush_wrapped = 1;
 337         }
 338 }
 339
 340 /**
 341  * gfs2_log_get_buf - Get and initialize a buffer to use for log control data
 342  * @sdp: The GFS2 superblock
 343  *
 344  * Returns: the buffer_head
 345  */
 346
 347 struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
 348 {
 349         uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 350         struct gfs2_log_buf *lb;
 351         struct buffer_head *bh;
 352
 353         lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
 354         list_add(&lb->lb_list, &sdp->sd_log_flush_list);
 355
 356         bh = lb->lb_bh = sb_getblk(sdp->sd_vfs, blkno);
 357         lock_buffer(bh);
 358         memset(bh->b_data, 0, bh->b_size);
 359         set_buffer_uptodate(bh);
 360         clear_buffer_dirty(bh);
 361         unlock_buffer(bh);
 362
 363         log_incr_head(sdp);
 364
 365         return bh;
 366 }
 367
 368 /**
 369  * gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
 370  * @sdp: the filesystem
 371  * @data: the data the buffer_head should point to
 372  *
 373  * Returns: the log buffer descriptor
 374  */
 375
 376 struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
 377                                       struct buffer_head *real)
 378 {
 379         uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 380         struct gfs2_log_buf *lb;
 381         struct buffer_head *bh;
 382
 383         lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
 384         list_add(&lb->lb_list, &sdp->sd_log_flush_list);
 385         lb->lb_real = real;
 386
 387         bh = lb->lb_bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
 388         atomic_set(&bh->b_count, 1);
 389         bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate);
 390         set_bh_page(bh, real->b_page, bh_offset(real));
 391         bh->b_blocknr = blkno;
 392         bh->b_size = sdp->sd_sb.sb_bsize;
 393         bh->b_bdev = sdp->sd_vfs->s_bdev;
 394
 395         log_incr_head(sdp);
 396
 397         return bh;
 398 }
 399
 400 static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail, int pull)
 401 {
 402         unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
 403
 404         ail2_empty(sdp, new_tail);
 405
 406         gfs2_log_lock(sdp);
 407         sdp->sd_log_blks_free += dist - ((pull) ? 1 : 0);
 408         gfs2_assert_withdraw(sdp,
 409                              sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
 410         gfs2_log_unlock(sdp);
 411
 412         sdp->sd_log_tail = new_tail;
 413 }
 414
 415 /**
 416  * log_write_header - Get and initialize a journal header buffer
 417  * @sdp: The GFS2 superblock
 418  *
 419  * Returns: the initialized log buffer descriptor
 420  */
 421
 422 static void log_write_header(struct gfs2_sbd *sdp, uint32_t flags, int pull)
 423 {
 424         uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 425         struct buffer_head *bh;
 426         struct gfs2_log_header *lh;
 427         unsigned int tail;
 428         uint32_t hash;
 429
 430         atomic_inc(&sdp->sd_log_flush_ondisk);
 431
 432         bh = sb_getblk(sdp->sd_vfs, blkno);
 433         lock_buffer(bh);
 434         memset(bh->b_data, 0, bh->b_size);
 435         set_buffer_uptodate(bh);
 436         clear_buffer_dirty(bh);
 437         unlock_buffer(bh);
 438
 439         gfs2_ail1_empty(sdp, 0);
 440         tail = current_tail(sdp);
 441
 442         lh = (struct gfs2_log_header *)bh->b_data;
 443         memset(lh, 0, sizeof(struct gfs2_log_header));
 444         lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
 445         lh->lh_header.mh_type = cpu_to_be16(GFS2_METATYPE_LH);
 446         lh->lh_header.mh_format = cpu_to_be16(GFS2_FORMAT_LH);
 447         lh->lh_sequence = be64_to_cpu(sdp->sd_log_sequence++);
 448         lh->lh_flags = be32_to_cpu(flags);
 449         lh->lh_tail = be32_to_cpu(tail);
 450         lh->lh_blkno = be32_to_cpu(sdp->sd_log_flush_head);
 451         hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));
 452         lh->lh_hash = cpu_to_be32(hash);
 453
 454         set_buffer_dirty(bh);
 455         if (sync_dirty_buffer(bh))
 456                 gfs2_io_error_bh(sdp, bh);
 457         brelse(bh);
 458
 459         if (sdp->sd_log_tail != tail)
 460                 log_pull_tail(sdp, tail, pull);
 461         else
 462                 gfs2_assert_withdraw(sdp, !pull);
 463
 464         sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
 465         log_incr_head(sdp);
 466 }
 467
 468 static void log_flush_commit(struct gfs2_sbd *sdp)
 469 {
 470         struct list_head *head = &sdp->sd_log_flush_list;
 471         struct gfs2_log_buf *lb;
 472         struct buffer_head *bh;
 473         unsigned int d;
 474
 475         d = log_distance(sdp, sdp->sd_log_flush_head, sdp->sd_log_head);
 476
 477         gfs2_assert_withdraw(sdp, d + 1 == sdp->sd_log_blks_reserved);
 478
 479         while (!list_empty(head)) {
 480                 lb = list_entry(head->next, struct gfs2_log_buf, lb_list);
 481                 list_del(&lb->lb_list);
 482                 bh = lb->lb_bh;
 483
 484                 wait_on_buffer(bh);
 485                 if (!buffer_uptodate(bh))
 486                         gfs2_io_error_bh(sdp, bh);
 487                 if (lb->lb_real) {
 488                         while (atomic_read(&bh->b_count) != 1)  /* Grrrr... */
 489                                 schedule();
 490                         free_buffer_head(bh);
 491                 } else
 492                         brelse(bh);
 493                 kfree(lb);
 494         }
 495
 496         log_write_header(sdp, 0, 0);
 497 }
 498
 499 /**
 500  * gfs2_log_flush_i - flush incore transaction(s)
 501  * @sdp: the filesystem
 502  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
 503  *
 504  */
 505
 506 void gfs2_log_flush_i(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 507 {
 508         struct gfs2_ail *ai;
 509
 510         atomic_inc(&sdp->sd_log_flush_incore);
 511
 512         ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
 513         INIT_LIST_HEAD(&ai->ai_ail1_list);
 514         INIT_LIST_HEAD(&ai->ai_ail2_list);
 515
 516         gfs2_lock_for_flush(sdp);
 517         down(&sdp->sd_log_flush_lock);
 518
 519         gfs2_assert_withdraw(sdp,
 520                         sdp->sd_log_num_buf == sdp->sd_log_commited_buf);
 521         gfs2_assert_withdraw(sdp,
 522                         sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
 523
 524         if (gl && list_empty(&gl->gl_le.le_list)) {
 525                 up(&sdp->sd_log_flush_lock);
 526                 gfs2_unlock_from_flush(sdp);
 527                 kfree(ai);
 528                 return;
 529         }
 530
 531         sdp->sd_log_flush_head = sdp->sd_log_head;
 532         sdp->sd_log_flush_wrapped = 0;
 533         ai->ai_first = sdp->sd_log_flush_head;
 534
 535         lops_before_commit(sdp);
 536         if (!list_empty(&sdp->sd_log_flush_list))
 537                 log_flush_commit(sdp);
 538         else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle)
 539                 log_write_header(sdp, 0, PULL);
 540         lops_after_commit(sdp, ai);
 541
 542         sdp->sd_log_head = sdp->sd_log_flush_head;
 543         if (sdp->sd_log_flush_wrapped)
 544                 sdp->sd_log_wraps++;
 545
 546         sdp->sd_log_blks_reserved =
 547                 sdp->sd_log_commited_buf =
 548                 sdp->sd_log_commited_revoke = 0;
 549
 550         gfs2_log_lock(sdp);
 551         if (!list_empty(&ai->ai_ail1_list)) {
 552                 list_add(&ai->ai_list, &sdp->sd_ail1_list);
 553                 ai = NULL;
 554         }
 555         gfs2_log_unlock(sdp);
 556
 557         up(&sdp->sd_log_flush_lock);
 558         sdp->sd_vfs->s_dirt = 0;
 559         gfs2_unlock_from_flush(sdp);
 560
 561         kfree(ai);
 562 }
 563
 564 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 565 {
 566         unsigned int reserved = 1;
 567         unsigned int old;
 568
 569         gfs2_log_lock(sdp);
 570
 571         sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
 572         gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_buf) >= 0);
 573         sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
 574         gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_revoke) >= 0);
 575
 576         if (sdp->sd_log_commited_buf)
 577                 reserved += 1 + sdp->sd_log_commited_buf + sdp->sd_log_commited_buf/503;
 578         if (sdp->sd_log_commited_revoke)
 579                 reserved += gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
 580                                             sizeof(uint64_t));
 581
 582         old = sdp->sd_log_blks_free;
 583         sdp->sd_log_blks_free += tr->tr_reserved -
 584                                  (reserved - sdp->sd_log_blks_reserved);
 585
 586         gfs2_assert_withdraw(sdp,
 587                              sdp->sd_log_blks_free >= old);
 588         gfs2_assert_withdraw(sdp,
 589                              sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
 590
 591         sdp->sd_log_blks_reserved = reserved;
 592
 593         gfs2_log_unlock(sdp);
 594 }
 595
 596 /**
 597  * gfs2_log_commit - Commit a transaction to the log
 598  * @sdp: the filesystem
 599  * @tr: the transaction
 600  *
 601  * Returns: errno
 602  */
 603
 604 void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 605 {
 606         log_refund(sdp, tr);
 607         lops_incore_commit(sdp, tr);
 608
 609         sdp->sd_vfs->s_dirt = 1;
 610         unlock_from_trans(sdp);
 611
 612         kfree(tr);
 613
 614         gfs2_log_lock(sdp);
 615         if (sdp->sd_log_num_buf > gfs2_tune_get(sdp, gt_incore_log_blocks)) {
 616                 gfs2_log_unlock(sdp);
 617                 gfs2_log_flush(sdp);
 618         } else
 619                 gfs2_log_unlock(sdp);
 620 }
 621
 622 /**
 623  * gfs2_log_shutdown - write a shutdown header into a journal
 624  * @sdp: the filesystem
 625  *
 626  */
 627
 628 void gfs2_log_shutdown(struct gfs2_sbd *sdp)
 629 {
 630         down(&sdp->sd_log_flush_lock);
 631
 632         gfs2_assert_withdraw(sdp, !atomic_read(&sdp->sd_log_trans_count));
 633         gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
 634         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_gl);
 635         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf);
 636         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_jdata);
 637         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
 638         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
 639         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
 640         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
 641
 642         sdp->sd_log_flush_head = sdp->sd_log_head;
 643         sdp->sd_log_flush_wrapped = 0;
 644
 645         log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT, 0);
 646
 647         gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free ==
 648                              sdp->sd_jdesc->jd_blocks);
 649         gfs2_assert_withdraw(sdp, sdp->sd_log_head == sdp->sd_log_tail);
 650         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail2_list));
 651
 652         sdp->sd_log_head = sdp->sd_log_flush_head;
 653         if (sdp->sd_log_flush_wrapped)
 654                 sdp->sd_log_wraps++;
 655         sdp->sd_log_tail = sdp->sd_log_head;
 656
 657         up(&sdp->sd_log_flush_lock);
 658 }
 659