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