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 <linux/gfs2_ondisk.h>
  16 #include <asm/semaphore.h>
  17
  18 #include "gfs2.h"
  19 #include "lm_interface.h"
  20 #include "incore.h"
  21 #include "bmap.h"
  22 #include "glock.h"
  23 #include "log.h"
  24 #include "lops.h"
  25 #include "meta_io.h"
  26 #include "util.h"
  27
  28 #define PULL 1
  29
  30 static void do_lock_wait(struct gfs2_sbd *sdp, wait_queue_head_t *wq,
  31                          atomic_t *a)
  32 {
  33         wait_event(*wq, atomic_read(a) ? 0 : 1);
  34 }
  35
  36 static void lock_for_trans(struct gfs2_sbd *sdp)
  37 {
  38         do_lock_wait(sdp, &sdp->sd_log_trans_wq, &sdp->sd_log_flush_count);
  39         atomic_inc(&sdp->sd_log_trans_count);
  40 }
  41
  42 static void unlock_from_trans(struct gfs2_sbd *sdp)
  43 {
  44         gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_trans_count));
  45         if (atomic_dec_and_test(&sdp->sd_log_trans_count))
  46                 wake_up(&sdp->sd_log_flush_wq);
  47 }
  48
  49 static void gfs2_lock_for_flush(struct gfs2_sbd *sdp)
  50 {
  51         atomic_inc(&sdp->sd_log_flush_count);
  52         do_lock_wait(sdp, &sdp->sd_log_flush_wq, &sdp->sd_log_trans_count);
  53 }
  54
  55 static void gfs2_unlock_from_flush(struct gfs2_sbd *sdp)
  56 {
  57         gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_flush_count));
  58         if (atomic_dec_and_test(&sdp->sd_log_flush_count))
  59                 wake_up(&sdp->sd_log_trans_wq);
  60 }
  61
  62 /**
  63  * gfs2_struct2blk - compute stuff
  64  * @sdp: the filesystem
  65  * @nstruct: the number of structures
  66  * @ssize: the size of the structures
  67  *
  68  * Compute the number of log descriptor blocks needed to hold a certain number
  69  * of structures of a certain size.
  70  *
  71  * Returns: the number of blocks needed (minimum is always 1)
  72  */
  73
  74 unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct,
  75                              unsigned int ssize)
  76 {
  77         unsigned int blks;
  78         unsigned int first, second;
  79
  80         blks = 1;
  81         first = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) /
  82                 ssize;
  83
  84         if (nstruct > first) {
  85                 second = (sdp->sd_sb.sb_bsize -
  86                           sizeof(struct gfs2_meta_header)) / ssize;
  87                 blks += DIV_ROUND_UP(nstruct - first, second);
  88         }
  89
  90         return blks;
  91 }
  92
  93 void gfs2_ail1_start(struct gfs2_sbd *sdp, int flags)
  94 {
  95         struct list_head *head = &sdp->sd_ail1_list;
  96         uint64_t sync_gen;
  97         struct list_head *first, *tmp;
  98         struct gfs2_ail *first_ai, *ai;
  99
 100         gfs2_log_lock(sdp);
 101         if (list_empty(head)) {
 102                 gfs2_log_unlock(sdp);
 103                 return;
 104         }
 105         sync_gen = sdp->sd_ail_sync_gen++;
 106
 107         first = head->prev;
 108         first_ai = list_entry(first, struct gfs2_ail, ai_list);
 109         first_ai->ai_sync_gen = sync_gen;
 110         gfs2_ail1_start_one(sdp, first_ai);
 111
 112         if (flags & DIO_ALL)
 113                 first = NULL;
 114
 115         for (;;) {
 116                 if (first &&
 117                     (head->prev != first ||
 118                      gfs2_ail1_empty_one(sdp, first_ai, 0)))
 119                         break;
 120
 121                 for (tmp = head->prev; tmp != head; tmp = tmp->prev) {
 122                         ai = list_entry(tmp, struct gfs2_ail, ai_list);
 123                         if (ai->ai_sync_gen >= sync_gen)
 124                                 continue;
 125                         ai->ai_sync_gen = sync_gen;
 126                         gfs2_ail1_start_one(sdp, ai);
 127                         break;
 128                 }
 129
 130                 if (tmp == head)
 131                         break;
 132         }
 133
 134         gfs2_log_unlock(sdp);
 135 }
 136
 137 int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags)
 138 {
 139         struct gfs2_ail *ai, *s;
 140         int ret;
 141
 142         gfs2_log_lock(sdp);
 143
 144         list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) {
 145                 if (gfs2_ail1_empty_one(sdp, ai, flags))
 146                         list_move(&ai->ai_list, &sdp->sd_ail2_list);
 147                 else if (!(flags & DIO_ALL))
 148                         break;
 149         }
 150
 151         ret = list_empty(&sdp->sd_ail1_list);
 152
 153         gfs2_log_unlock(sdp);
 154
 155         return ret;
 156 }
 157
 158 static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
 159 {
 160         struct gfs2_ail *ai, *safe;
 161         unsigned int old_tail = sdp->sd_log_tail;
 162         int wrap = (new_tail < old_tail);
 163         int a, b, rm;
 164
 165         gfs2_log_lock(sdp);
 166
 167         list_for_each_entry_safe(ai, safe, &sdp->sd_ail2_list, ai_list) {
 168                 a = (old_tail <= ai->ai_first);
 169                 b = (ai->ai_first < new_tail);
 170                 rm = (wrap) ? (a || b) : (a && b);
 171                 if (!rm)
 172                         continue;
 173
 174                 gfs2_ail2_empty_one(sdp, ai);
 175                 list_del(&ai->ai_list);
 176                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail1_list));
 177                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail2_list));
 178                 kfree(ai);
 179         }
 180
 181         gfs2_log_unlock(sdp);
 182 }
 183
 184 /**
 185  * gfs2_log_reserve - Make a log reservation
 186  * @sdp: The GFS2 superblock
 187  * @blks: The number of blocks to reserve
 188  *
 189  * Returns: errno
 190  */
 191
 192 int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 193 {
 194         LIST_HEAD(list);
 195         unsigned int try = 0;
 196
 197         if (gfs2_assert_warn(sdp, blks) ||
 198             gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
 199                 return -EINVAL;
 200
 201         for (;;) {
 202                 gfs2_log_lock(sdp);
 203                 if (list_empty(&list)) {
 204                         list_add_tail(&list, &sdp->sd_log_blks_list);
 205                         while (sdp->sd_log_blks_list.next != &list) {
 206                                 DECLARE_WAITQUEUE(__wait_chan, current);
 207                                 set_current_state(TASK_UNINTERRUPTIBLE);
 208                                 add_wait_queue(&sdp->sd_log_blks_wait,
 209                                                &__wait_chan);
 210                                 gfs2_log_unlock(sdp);
 211                                 schedule();
 212                                 gfs2_log_lock(sdp);
 213                                 remove_wait_queue(&sdp->sd_log_blks_wait,
 214                                                   &__wait_chan);
 215                                 set_current_state(TASK_RUNNING);
 216                         }
 217                 }
 218                 /* Never give away the last block so we can
 219                    always pull the tail if we need to. */
 220                 if (sdp->sd_log_blks_free > blks) {
 221                         sdp->sd_log_blks_free -= blks;
 222                         list_del(&list);
 223                         gfs2_log_unlock(sdp);
 224                         wake_up(&sdp->sd_log_blks_wait);
 225                         break;
 226                 }
 227
 228                 gfs2_log_unlock(sdp);
 229                 gfs2_ail1_empty(sdp, 0);
 230                 gfs2_log_flush(sdp);
 231
 232                 if (try++)
 233                         gfs2_ail1_start(sdp, 0);
 234         }
 235         lock_for_trans(sdp);
 236
 237         return 0;
 238 }
 239
 240 /**
 241  * gfs2_log_release - Release a given number of log blocks
 242  * @sdp: The GFS2 superblock
 243  * @blks: The number of blocks
 244  *
 245  */
 246
 247 void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
 248 {
 249         unlock_from_trans(sdp);
 250
 251         gfs2_log_lock(sdp);
 252         sdp->sd_log_blks_free += blks;
 253         gfs2_assert_withdraw(sdp,
 254                              sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
 255         gfs2_log_unlock(sdp);
 256 }
 257
 258 static uint64_t log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
 259 {
 260         int new = 0;
 261         uint64_t dbn;
 262         int error;
 263
 264         error = gfs2_block_map(sdp->sd_jdesc->jd_inode->u.generic_ip,
 265                                lbn, &new, &dbn, NULL);
 266         gfs2_assert_withdraw(sdp, !error && dbn);
 267
 268         return dbn;
 269 }
 270
 271 /**
 272  * log_distance - Compute distance between two journal blocks
 273  * @sdp: The GFS2 superblock
 274  * @newer: The most recent journal block of the pair
 275  * @older: The older journal block of the pair
 276  *
 277  *   Compute the distance (in the journal direction) between two
 278  *   blocks in the journal
 279  *
 280  * Returns: the distance in blocks
 281  */
 282
 283 static inline unsigned int log_distance(struct gfs2_sbd *sdp,
 284                                         unsigned int newer,
 285                                         unsigned int older)
 286 {
 287         int dist;
 288
 289         dist = newer - older;
 290         if (dist < 0)
 291                 dist += sdp->sd_jdesc->jd_blocks;
 292
 293         return dist;
 294 }
 295
 296 static unsigned int current_tail(struct gfs2_sbd *sdp)
 297 {
 298         struct gfs2_ail *ai;
 299         unsigned int tail;
 300
 301         gfs2_log_lock(sdp);
 302
 303         if (list_empty(&sdp->sd_ail1_list))
 304                 tail = sdp->sd_log_head;
 305         else {
 306                 ai = list_entry(sdp->sd_ail1_list.prev,
 307                                 struct gfs2_ail, ai_list);
 308                 tail = ai->ai_first;
 309         }
 310
 311         gfs2_log_unlock(sdp);
 312
 313         return tail;
 314 }
 315
 316 static inline void log_incr_head(struct gfs2_sbd *sdp)
 317 {
 318         if (sdp->sd_log_flush_head == sdp->sd_log_tail)
 319                 gfs2_assert_withdraw(sdp,
 320                                 sdp->sd_log_flush_head == sdp->sd_log_head);
 321
 322         if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
 323                 sdp->sd_log_flush_head = 0;
 324                 sdp->sd_log_flush_wrapped = 1;
 325         }
 326 }
 327
 328 /**
 329  * gfs2_log_get_buf - Get and initialize a buffer to use for log control data
 330  * @sdp: The GFS2 superblock
 331  *
 332  * Returns: the buffer_head
 333  */
 334
 335 struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
 336 {
 337         uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 338         struct gfs2_log_buf *lb;
 339         struct buffer_head *bh;
 340
 341         lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
 342         list_add(&lb->lb_list, &sdp->sd_log_flush_list);
 343
 344         bh = lb->lb_bh = sb_getblk(sdp->sd_vfs, blkno);
 345         lock_buffer(bh);
 346         memset(bh->b_data, 0, bh->b_size);
 347         set_buffer_uptodate(bh);
 348         clear_buffer_dirty(bh);
 349         unlock_buffer(bh);
 350
 351         log_incr_head(sdp);
 352
 353         return bh;
 354 }
 355
 356 /**
 357  * gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
 358  * @sdp: the filesystem
 359  * @data: the data the buffer_head should point to
 360  *
 361  * Returns: the log buffer descriptor
 362  */
 363
 364 struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
 365                                       struct buffer_head *real)
 366 {
 367         uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 368         struct gfs2_log_buf *lb;
 369         struct buffer_head *bh;
 370
 371         lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
 372         list_add(&lb->lb_list, &sdp->sd_log_flush_list);
 373         lb->lb_real = real;
 374
 375         bh = lb->lb_bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
 376         atomic_set(&bh->b_count, 1);
 377         bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate);
 378         set_bh_page(bh, real->b_page, bh_offset(real));
 379         bh->b_blocknr = blkno;
 380         bh->b_size = sdp->sd_sb.sb_bsize;
 381         bh->b_bdev = sdp->sd_vfs->s_bdev;
 382
 383         log_incr_head(sdp);
 384
 385         return bh;
 386 }
 387
 388 static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail, int pull)
 389 {
 390         unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
 391
 392         ail2_empty(sdp, new_tail);
 393
 394         gfs2_log_lock(sdp);
 395         sdp->sd_log_blks_free += dist - ((pull) ? 1 : 0);
 396         gfs2_assert_withdraw(sdp,
 397                              sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
 398         gfs2_log_unlock(sdp);
 399
 400         sdp->sd_log_tail = new_tail;
 401 }
 402
 403 /**
 404  * log_write_header - Get and initialize a journal header buffer
 405  * @sdp: The GFS2 superblock
 406  *
 407  * Returns: the initialized log buffer descriptor
 408  */
 409
 410 static void log_write_header(struct gfs2_sbd *sdp, uint32_t flags, int pull)
 411 {
 412         uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 413         struct buffer_head *bh;
 414         struct gfs2_log_header *lh;
 415         unsigned int tail;
 416         uint32_t hash;
 417
 418         bh = sb_getblk(sdp->sd_vfs, blkno);
 419         lock_buffer(bh);
 420         memset(bh->b_data, 0, bh->b_size);
 421         set_buffer_uptodate(bh);
 422         clear_buffer_dirty(bh);
 423         unlock_buffer(bh);
 424
 425         gfs2_ail1_empty(sdp, 0);
 426         tail = current_tail(sdp);
 427
 428         lh = (struct gfs2_log_header *)bh->b_data;
 429         memset(lh, 0, sizeof(struct gfs2_log_header));
 430         lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
 431         lh->lh_header.mh_type = cpu_to_be16(GFS2_METATYPE_LH);
 432         lh->lh_header.mh_format = cpu_to_be16(GFS2_FORMAT_LH);
 433         lh->lh_sequence = be64_to_cpu(sdp->sd_log_sequence++);
 434         lh->lh_flags = be32_to_cpu(flags);
 435         lh->lh_tail = be32_to_cpu(tail);
 436         lh->lh_blkno = be32_to_cpu(sdp->sd_log_flush_head);
 437         hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));
 438         lh->lh_hash = cpu_to_be32(hash);
 439
 440         set_buffer_dirty(bh);
 441         if (sync_dirty_buffer(bh))
 442                 gfs2_io_error_bh(sdp, bh);
 443         brelse(bh);
 444
 445         if (sdp->sd_log_tail != tail)
 446                 log_pull_tail(sdp, tail, pull);
 447         else
 448                 gfs2_assert_withdraw(sdp, !pull);
 449
 450         sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
 451         log_incr_head(sdp);
 452 }
 453
 454 static void log_flush_commit(struct gfs2_sbd *sdp)
 455 {
 456         struct list_head *head = &sdp->sd_log_flush_list;
 457         struct gfs2_log_buf *lb;
 458         struct buffer_head *bh;
 459         unsigned int d;
 460
 461         d = log_distance(sdp, sdp->sd_log_flush_head, sdp->sd_log_head);
 462
 463         gfs2_assert_withdraw(sdp, d + 1 == sdp->sd_log_blks_reserved);
 464
 465         while (!list_empty(head)) {
 466                 lb = list_entry(head->next, struct gfs2_log_buf, lb_list);
 467                 list_del(&lb->lb_list);
 468                 bh = lb->lb_bh;
 469
 470                 wait_on_buffer(bh);
 471                 if (!buffer_uptodate(bh))
 472                         gfs2_io_error_bh(sdp, bh);
 473                 if (lb->lb_real) {
 474                         while (atomic_read(&bh->b_count) != 1)  /* Grrrr... */
 475                                 schedule();
 476                         free_buffer_head(bh);
 477                 } else
 478                         brelse(bh);
 479                 kfree(lb);
 480         }
 481
 482         log_write_header(sdp, 0, 0);
 483 }
 484
 485 /**
 486  * gfs2_log_flush_i - flush incore transaction(s)
 487  * @sdp: the filesystem
 488  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
 489  *
 490  */
 491
 492 void gfs2_log_flush_i(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 493 {
 494         struct gfs2_ail *ai;
 495
 496         ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
 497         INIT_LIST_HEAD(&ai->ai_ail1_list);
 498         INIT_LIST_HEAD(&ai->ai_ail2_list);
 499         gfs2_lock_for_flush(sdp);
 500
 501         if (gl) {
 502                 gfs2_log_lock(sdp);
 503                 if (list_empty(&gl->gl_le.le_list)) {
 504                         gfs2_log_unlock(sdp);
 505                         gfs2_unlock_from_flush(sdp);
 506                         kfree(ai);
 507                         return;
 508                 }
 509                 gfs2_log_unlock(sdp);
 510         }
 511
 512         mutex_lock(&sdp->sd_log_flush_lock);
 513
 514         gfs2_assert_withdraw(sdp,
 515                         sdp->sd_log_num_buf == sdp->sd_log_commited_buf);
 516         gfs2_assert_withdraw(sdp,
 517                         sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
 518
 519         sdp->sd_log_flush_head = sdp->sd_log_head;
 520         sdp->sd_log_flush_wrapped = 0;
 521         ai->ai_first = sdp->sd_log_flush_head;
 522
 523         lops_before_commit(sdp);
 524         if (!list_empty(&sdp->sd_log_flush_list))
 525                 log_flush_commit(sdp);
 526         else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle)
 527                 log_write_header(sdp, 0, PULL);
 528         lops_after_commit(sdp, ai);
 529         sdp->sd_log_head = sdp->sd_log_flush_head;
 530         if (sdp->sd_log_flush_wrapped)
 531                 sdp->sd_log_wraps++;
 532
 533         sdp->sd_log_blks_reserved =
 534                 sdp->sd_log_commited_buf =
 535                 sdp->sd_log_commited_revoke = 0;
 536
 537         gfs2_log_lock(sdp);
 538         if (!list_empty(&ai->ai_ail1_list)) {
 539                 list_add(&ai->ai_list, &sdp->sd_ail1_list);
 540                 ai = NULL;
 541         }
 542         gfs2_log_unlock(sdp);
 543
 544         mutex_unlock(&sdp->sd_log_flush_lock);
 545         sdp->sd_vfs->s_dirt = 0;
 546         gfs2_unlock_from_flush(sdp);
 547
 548         kfree(ai);
 549 }
 550
 551 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 552 {
 553         unsigned int reserved = 1;
 554         unsigned int old;
 555
 556         gfs2_log_lock(sdp);
 557
 558         sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
 559         gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_buf) >= 0);
 560         sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
 561         gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_revoke) >= 0);
 562
 563         if (sdp->sd_log_commited_buf)
 564                 reserved += 1 + sdp->sd_log_commited_buf +
 565                             sdp->sd_log_commited_buf/503;
 566         if (sdp->sd_log_commited_revoke)
 567                 reserved += gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
 568                                             sizeof(uint64_t));
 569
 570         old = sdp->sd_log_blks_free;
 571         sdp->sd_log_blks_free += tr->tr_reserved -
 572                                  (reserved - sdp->sd_log_blks_reserved);
 573
 574         gfs2_assert_withdraw(sdp,
 575                              sdp->sd_log_blks_free >= old);
 576         gfs2_assert_withdraw(sdp,
 577                              sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
 578
 579         sdp->sd_log_blks_reserved = reserved;
 580
 581         gfs2_log_unlock(sdp);
 582 }
 583
 584 /**
 585  * gfs2_log_commit - Commit a transaction to the log
 586  * @sdp: the filesystem
 587  * @tr: the transaction
 588  *
 589  * Returns: errno
 590  */
 591
 592 void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 593 {
 594         log_refund(sdp, tr);
 595         lops_incore_commit(sdp, tr);
 596
 597         sdp->sd_vfs->s_dirt = 1;
 598         unlock_from_trans(sdp);
 599
 600         gfs2_log_lock(sdp);
 601         if (sdp->sd_log_num_buf > gfs2_tune_get(sdp, gt_incore_log_blocks)) {
 602                 gfs2_log_unlock(sdp);
 603                 gfs2_log_flush(sdp);
 604         } else
 605                 gfs2_log_unlock(sdp);
 606 }
 607
 608 /**
 609  * gfs2_log_shutdown - write a shutdown header into a journal
 610  * @sdp: the filesystem
 611  *
 612  */
 613
 614 void gfs2_log_shutdown(struct gfs2_sbd *sdp)
 615 {
 616         mutex_lock(&sdp->sd_log_flush_lock);
 617
 618         gfs2_assert_withdraw(sdp, !atomic_read(&sdp->sd_log_trans_count));
 619         gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
 620         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_gl);
 621         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf);
 622         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_jdata);
 623         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
 624         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
 625         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
 626         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
 627
 628         sdp->sd_log_flush_head = sdp->sd_log_head;
 629         sdp->sd_log_flush_wrapped = 0;
 630
 631         log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT, 0);
 632
 633         gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free ==
 634                              sdp->sd_jdesc->jd_blocks);
 635         gfs2_assert_withdraw(sdp, sdp->sd_log_head == sdp->sd_log_tail);
 636         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail2_list));
 637
 638         sdp->sd_log_head = sdp->sd_log_flush_head;
 639         if (sdp->sd_log_flush_wrapped)
 640                 sdp->sd_log_wraps++;
 641         sdp->sd_log_tail = sdp->sd_log_head;
 642
 643         mutex_unlock(&sdp->sd_log_flush_lock);
 644 }
 645