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 <linux/crc32.h>
  17 #include <asm/semaphore.h>
  18
  19 #include "gfs2.h"
  20 #include "lm_interface.h"
  21 #include "incore.h"
  22 #include "bmap.h"
  23 #include "glock.h"
  24 #include "log.h"
  25 #include "lops.h"
  26 #include "meta_io.h"
  27 #include "util.h"
  28 #include "dir.h"
  29
  30 #define PULL 1
  31
  32 static void lock_for_trans(struct gfs2_sbd *sdp)
  33 {
  34         wait_event(sdp->sd_log_trans_wq, atomic_read(&sdp->sd_log_flush_count) ? 0 : 1);
  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         wait_event(sdp->sd_log_flush_wq, atomic_read(&sdp->sd_log_trans_count) ? 0 : 1);
  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_ROUND_UP(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         unsigned int try = 0;
 191
 192         if (gfs2_assert_warn(sdp, blks) ||
 193             gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
 194                 return -EINVAL;
 195
 196         mutex_lock(&sdp->sd_log_reserve_mutex);
 197         for (;;) {
 198                 gfs2_log_lock(sdp);
 199                 if (sdp->sd_log_blks_free > blks) {
 200                         sdp->sd_log_blks_free -= blks;
 201                         gfs2_log_unlock(sdp);
 202                         mutex_unlock(&sdp->sd_log_reserve_mutex);
 203                         break;
 204                 }
 205
 206                 gfs2_log_unlock(sdp);
 207                 gfs2_ail1_empty(sdp, 0);
 208                 gfs2_log_flush(sdp);
 209
 210                 if (try++)
 211                         gfs2_ail1_start(sdp, 0);
 212         }
 213         lock_for_trans(sdp);
 214
 215         return 0;
 216 }
 217
 218 /**
 219  * gfs2_log_release - Release a given number of log blocks
 220  * @sdp: The GFS2 superblock
 221  * @blks: The number of blocks
 222  *
 223  */
 224
 225 void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
 226 {
 227         unlock_from_trans(sdp);
 228
 229         gfs2_log_lock(sdp);
 230         sdp->sd_log_blks_free += blks;
 231         gfs2_assert_withdraw(sdp,
 232                              sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
 233         gfs2_log_unlock(sdp);
 234 }
 235
 236 static uint64_t log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
 237 {
 238         int new = 0;
 239         uint64_t dbn;
 240         int error;
 241
 242         error = gfs2_block_map(sdp->sd_jdesc->jd_inode->u.generic_ip,
 243                                lbn, &new, &dbn, NULL);
 244         gfs2_assert_withdraw(sdp, !error && dbn);
 245
 246         return dbn;
 247 }
 248
 249 /**
 250  * log_distance - Compute distance between two journal blocks
 251  * @sdp: The GFS2 superblock
 252  * @newer: The most recent journal block of the pair
 253  * @older: The older journal block of the pair
 254  *
 255  *   Compute the distance (in the journal direction) between two
 256  *   blocks in the journal
 257  *
 258  * Returns: the distance in blocks
 259  */
 260
 261 static inline unsigned int log_distance(struct gfs2_sbd *sdp,
 262                                         unsigned int newer,
 263                                         unsigned int older)
 264 {
 265         int dist;
 266
 267         dist = newer - older;
 268         if (dist < 0)
 269                 dist += sdp->sd_jdesc->jd_blocks;
 270
 271         return dist;
 272 }
 273
 274 static unsigned int current_tail(struct gfs2_sbd *sdp)
 275 {
 276         struct gfs2_ail *ai;
 277         unsigned int tail;
 278
 279         gfs2_log_lock(sdp);
 280
 281         if (list_empty(&sdp->sd_ail1_list))
 282                 tail = sdp->sd_log_head;
 283         else {
 284                 ai = list_entry(sdp->sd_ail1_list.prev,
 285                                 struct gfs2_ail, ai_list);
 286                 tail = ai->ai_first;
 287         }
 288
 289         gfs2_log_unlock(sdp);
 290
 291         return tail;
 292 }
 293
 294 static inline void log_incr_head(struct gfs2_sbd *sdp)
 295 {
 296         if (sdp->sd_log_flush_head == sdp->sd_log_tail)
 297                 gfs2_assert_withdraw(sdp,
 298                                 sdp->sd_log_flush_head == sdp->sd_log_head);
 299
 300         if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
 301                 sdp->sd_log_flush_head = 0;
 302                 sdp->sd_log_flush_wrapped = 1;
 303         }
 304 }
 305
 306 /**
 307  * gfs2_log_get_buf - Get and initialize a buffer to use for log control data
 308  * @sdp: The GFS2 superblock
 309  *
 310  * Returns: the buffer_head
 311  */
 312
 313 struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
 314 {
 315         uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 316         struct gfs2_log_buf *lb;
 317         struct buffer_head *bh;
 318
 319         lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
 320         list_add(&lb->lb_list, &sdp->sd_log_flush_list);
 321
 322         bh = lb->lb_bh = sb_getblk(sdp->sd_vfs, blkno);
 323         lock_buffer(bh);
 324         memset(bh->b_data, 0, bh->b_size);
 325         set_buffer_uptodate(bh);
 326         clear_buffer_dirty(bh);
 327         unlock_buffer(bh);
 328
 329         log_incr_head(sdp);
 330
 331         return bh;
 332 }
 333
 334 /**
 335  * gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
 336  * @sdp: the filesystem
 337  * @data: the data the buffer_head should point to
 338  *
 339  * Returns: the log buffer descriptor
 340  */
 341
 342 struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
 343                                       struct buffer_head *real)
 344 {
 345         uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 346         struct gfs2_log_buf *lb;
 347         struct buffer_head *bh;
 348
 349         lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
 350         list_add(&lb->lb_list, &sdp->sd_log_flush_list);
 351         lb->lb_real = real;
 352
 353         bh = lb->lb_bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
 354         atomic_set(&bh->b_count, 1);
 355         bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate);
 356         set_bh_page(bh, real->b_page, bh_offset(real));
 357         bh->b_blocknr = blkno;
 358         bh->b_size = sdp->sd_sb.sb_bsize;
 359         bh->b_bdev = sdp->sd_vfs->s_bdev;
 360
 361         log_incr_head(sdp);
 362
 363         return bh;
 364 }
 365
 366 static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail, int pull)
 367 {
 368         unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
 369
 370         ail2_empty(sdp, new_tail);
 371
 372         gfs2_log_lock(sdp);
 373         sdp->sd_log_blks_free += dist - ((pull) ? 1 : 0);
 374         gfs2_assert_withdraw(sdp,
 375                              sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
 376         gfs2_log_unlock(sdp);
 377
 378         sdp->sd_log_tail = new_tail;
 379 }
 380
 381 /**
 382  * log_write_header - Get and initialize a journal header buffer
 383  * @sdp: The GFS2 superblock
 384  *
 385  * Returns: the initialized log buffer descriptor
 386  */
 387
 388 static void log_write_header(struct gfs2_sbd *sdp, uint32_t flags, int pull)
 389 {
 390         uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 391         struct buffer_head *bh;
 392         struct gfs2_log_header *lh;
 393         unsigned int tail;
 394         uint32_t hash;
 395
 396         bh = sb_getblk(sdp->sd_vfs, blkno);
 397         lock_buffer(bh);
 398         memset(bh->b_data, 0, bh->b_size);
 399         set_buffer_uptodate(bh);
 400         clear_buffer_dirty(bh);
 401         unlock_buffer(bh);
 402
 403         gfs2_ail1_empty(sdp, 0);
 404         tail = current_tail(sdp);
 405
 406         lh = (struct gfs2_log_header *)bh->b_data;
 407         memset(lh, 0, sizeof(struct gfs2_log_header));
 408         lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
 409         lh->lh_header.mh_type = cpu_to_be16(GFS2_METATYPE_LH);
 410         lh->lh_header.mh_format = cpu_to_be16(GFS2_FORMAT_LH);
 411         lh->lh_sequence = be64_to_cpu(sdp->sd_log_sequence++);
 412         lh->lh_flags = be32_to_cpu(flags);
 413         lh->lh_tail = be32_to_cpu(tail);
 414         lh->lh_blkno = be32_to_cpu(sdp->sd_log_flush_head);
 415         hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));
 416         lh->lh_hash = cpu_to_be32(hash);
 417
 418         set_buffer_dirty(bh);
 419         if (sync_dirty_buffer(bh))
 420                 gfs2_io_error_bh(sdp, bh);
 421         brelse(bh);
 422
 423         if (sdp->sd_log_tail != tail)
 424                 log_pull_tail(sdp, tail, pull);
 425         else
 426                 gfs2_assert_withdraw(sdp, !pull);
 427
 428         sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
 429         log_incr_head(sdp);
 430 }
 431
 432 static void log_flush_commit(struct gfs2_sbd *sdp)
 433 {
 434         struct list_head *head = &sdp->sd_log_flush_list;
 435         struct gfs2_log_buf *lb;
 436         struct buffer_head *bh;
 437         unsigned int d;
 438
 439         d = log_distance(sdp, sdp->sd_log_flush_head, sdp->sd_log_head);
 440
 441         gfs2_assert_withdraw(sdp, d + 1 == sdp->sd_log_blks_reserved);
 442
 443         while (!list_empty(head)) {
 444                 lb = list_entry(head->next, struct gfs2_log_buf, lb_list);
 445                 list_del(&lb->lb_list);
 446                 bh = lb->lb_bh;
 447
 448                 wait_on_buffer(bh);
 449                 if (!buffer_uptodate(bh))
 450                         gfs2_io_error_bh(sdp, bh);
 451                 if (lb->lb_real) {
 452                         while (atomic_read(&bh->b_count) != 1)  /* Grrrr... */
 453                                 schedule();
 454                         free_buffer_head(bh);
 455                 } else
 456                         brelse(bh);
 457                 kfree(lb);
 458         }
 459
 460         log_write_header(sdp, 0, 0);
 461 }
 462
 463 /**
 464  * gfs2_log_flush_i - flush incore transaction(s)
 465  * @sdp: the filesystem
 466  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
 467  *
 468  */
 469
 470 void gfs2_log_flush_i(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 471 {
 472         struct gfs2_ail *ai;
 473
 474         ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
 475         INIT_LIST_HEAD(&ai->ai_ail1_list);
 476         INIT_LIST_HEAD(&ai->ai_ail2_list);
 477         gfs2_lock_for_flush(sdp);
 478
 479         if (gl) {
 480                 gfs2_log_lock(sdp);
 481                 if (list_empty(&gl->gl_le.le_list)) {
 482                         gfs2_log_unlock(sdp);
 483                         gfs2_unlock_from_flush(sdp);
 484                         kfree(ai);
 485                         return;
 486                 }
 487                 gfs2_log_unlock(sdp);
 488         }
 489
 490         mutex_lock(&sdp->sd_log_flush_lock);
 491
 492         gfs2_assert_withdraw(sdp,
 493                         sdp->sd_log_num_buf == sdp->sd_log_commited_buf);
 494         gfs2_assert_withdraw(sdp,
 495                         sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
 496
 497         sdp->sd_log_flush_head = sdp->sd_log_head;
 498         sdp->sd_log_flush_wrapped = 0;
 499         ai->ai_first = sdp->sd_log_flush_head;
 500
 501         lops_before_commit(sdp);
 502         if (!list_empty(&sdp->sd_log_flush_list))
 503                 log_flush_commit(sdp);
 504         else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle)
 505                 log_write_header(sdp, 0, PULL);
 506         lops_after_commit(sdp, ai);
 507         sdp->sd_log_head = sdp->sd_log_flush_head;
 508         if (sdp->sd_log_flush_wrapped)
 509                 sdp->sd_log_wraps++;
 510
 511         sdp->sd_log_blks_reserved =
 512                 sdp->sd_log_commited_buf =
 513                 sdp->sd_log_commited_revoke = 0;
 514
 515         gfs2_log_lock(sdp);
 516         if (!list_empty(&ai->ai_ail1_list)) {
 517                 list_add(&ai->ai_list, &sdp->sd_ail1_list);
 518                 ai = NULL;
 519         }
 520         gfs2_log_unlock(sdp);
 521
 522         mutex_unlock(&sdp->sd_log_flush_lock);
 523         sdp->sd_vfs->s_dirt = 0;
 524         gfs2_unlock_from_flush(sdp);
 525
 526         kfree(ai);
 527 }
 528
 529 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 530 {
 531         unsigned int reserved = 1;
 532         unsigned int old;
 533
 534         gfs2_log_lock(sdp);
 535
 536         sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
 537         gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_buf) >= 0);
 538         sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
 539         gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_revoke) >= 0);
 540
 541         if (sdp->sd_log_commited_buf)
 542                 reserved += 1 + sdp->sd_log_commited_buf +
 543                             sdp->sd_log_commited_buf/503;
 544         if (sdp->sd_log_commited_revoke)
 545                 reserved += gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
 546                                             sizeof(uint64_t));
 547
 548         old = sdp->sd_log_blks_free;
 549         sdp->sd_log_blks_free += tr->tr_reserved -
 550                                  (reserved - sdp->sd_log_blks_reserved);
 551
 552         gfs2_assert_withdraw(sdp,
 553                              sdp->sd_log_blks_free >= old);
 554         gfs2_assert_withdraw(sdp,
 555                              sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
 556
 557         sdp->sd_log_blks_reserved = reserved;
 558
 559         gfs2_log_unlock(sdp);
 560 }
 561
 562 /**
 563  * gfs2_log_commit - Commit a transaction to the log
 564  * @sdp: the filesystem
 565  * @tr: the transaction
 566  *
 567  * Returns: errno
 568  */
 569
 570 void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 571 {
 572         log_refund(sdp, tr);
 573         lops_incore_commit(sdp, tr);
 574
 575         sdp->sd_vfs->s_dirt = 1;
 576         unlock_from_trans(sdp);
 577
 578         gfs2_log_lock(sdp);
 579         if (sdp->sd_log_num_buf > gfs2_tune_get(sdp, gt_incore_log_blocks)) {
 580                 gfs2_log_unlock(sdp);
 581                 gfs2_log_flush(sdp);
 582         } else
 583                 gfs2_log_unlock(sdp);
 584 }
 585
 586 /**
 587  * gfs2_log_shutdown - write a shutdown header into a journal
 588  * @sdp: the filesystem
 589  *
 590  */
 591
 592 void gfs2_log_shutdown(struct gfs2_sbd *sdp)
 593 {
 594         mutex_lock(&sdp->sd_log_flush_lock);
 595
 596         gfs2_assert_withdraw(sdp, !atomic_read(&sdp->sd_log_trans_count));
 597         gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
 598         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_gl);
 599         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf);
 600         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_jdata);
 601         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
 602         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
 603         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
 604         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
 605
 606         sdp->sd_log_flush_head = sdp->sd_log_head;
 607         sdp->sd_log_flush_wrapped = 0;
 608
 609         log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT, 0);
 610
 611         gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free ==
 612                              sdp->sd_jdesc->jd_blocks);
 613         gfs2_assert_withdraw(sdp, sdp->sd_log_head == sdp->sd_log_tail);
 614         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail2_list));
 615
 616         sdp->sd_log_head = sdp->sd_log_flush_head;
 617         if (sdp->sd_log_flush_wrapped)
 618                 sdp->sd_log_wraps++;
 619         sdp->sd_log_tail = sdp->sd_log_head;
 620
 621         mutex_unlock(&sdp->sd_log_flush_lock);
 622 }
 623