fs/gfs2/log.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2007 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 version 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 <linux/delay.h>
  18 #include <linux/kthread.h>
  19 #include <linux/freezer.h>
  20 #include <linux/bio.h>
  21 #include <linux/writeback.h>
  22
  23 #include "gfs2.h"
  24 #include "incore.h"
  25 #include "bmap.h"
  26 #include "glock.h"
  27 #include "log.h"
  28 #include "lops.h"
  29 #include "meta_io.h"
  30 #include "util.h"
  31 #include "dir.h"
  32 #include "trace_gfs2.h"
  33
  34 #define PULL 1
  35
  36 /**
  37  * gfs2_struct2blk - compute stuff
  38  * @sdp: the filesystem
  39  * @nstruct: the number of structures
  40  * @ssize: the size of the structures
  41  *
  42  * Compute the number of log descriptor blocks needed to hold a certain number
  43  * of structures of a certain size.
  44  *
  45  * Returns: the number of blocks needed (minimum is always 1)
  46  */
  47
  48 unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct,
  49                              unsigned int ssize)
  50 {
  51         unsigned int blks;
  52         unsigned int first, second;
  53
  54         blks = 1;
  55         first = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) / ssize;
  56
  57         if (nstruct > first) {
  58                 second = (sdp->sd_sb.sb_bsize -
  59                           sizeof(struct gfs2_meta_header)) / ssize;
  60                 blks += DIV_ROUND_UP(nstruct - first, second);
  61         }
  62
  63         return blks;
  64 }
  65
  66 /**
  67  * gfs2_remove_from_ail - Remove an entry from the ail lists, updating counters
  68  * @mapping: The associated mapping (maybe NULL)
  69  * @bd: The gfs2_bufdata to remove
  70  *
  71  * The ail lock _must_ be held when calling this function
  72  *
  73  */
  74
  75 void gfs2_remove_from_ail(struct gfs2_bufdata *bd)
  76 {
  77         bd->bd_ail = NULL;
  78         list_del_init(&bd->bd_ail_st_list);
  79         list_del_init(&bd->bd_ail_gl_list);
  80         atomic_dec(&bd->bd_gl->gl_ail_count);
  81         brelse(bd->bd_bh);
  82 }
  83
  84 /**
  85  * gfs2_ail1_start_one - Start I/O on a part of the AIL
  86  * @sdp: the filesystem
  87  * @wbc: The writeback control structure
  88  * @ai: The ail structure
  89  *
  90  */
  91
  92 static int gfs2_ail1_start_one(struct gfs2_sbd *sdp,
  93                                struct writeback_control *wbc,
  94                                struct gfs2_ail *ai)
  95 __releases(&sdp->sd_ail_lock)
  96 __acquires(&sdp->sd_ail_lock)
  97 {
  98         struct gfs2_glock *gl = NULL;
  99         struct address_space *mapping;
 100         struct gfs2_bufdata *bd, *s;
 101         struct buffer_head *bh;
 102
 103         list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list, bd_ail_st_list) {
 104                 bh = bd->bd_bh;
 105
 106                 gfs2_assert(sdp, bd->bd_ail == ai);
 107
 108                 if (!buffer_busy(bh)) {
 109                         if (!buffer_uptodate(bh))
 110                                 gfs2_io_error_bh(sdp, bh);
 111                         list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
 112                         continue;
 113                 }
 114
 115                 if (!buffer_dirty(bh))
 116                         continue;
 117                 if (gl == bd->bd_gl)
 118                         continue;
 119                 gl = bd->bd_gl;
 120                 list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list);
 121                 mapping = bh->b_page->mapping;
 122                 if (!mapping)
 123                         continue;
 124                 spin_unlock(&sdp->sd_ail_lock);
 125                 generic_writepages(mapping, wbc);
 126                 spin_lock(&sdp->sd_ail_lock);
 127                 if (wbc->nr_to_write <= 0)
 128                         break;
 129                 return 1;
 130         }
 131
 132         return 0;
 133 }
 134
 135
 136 /**
 137  * gfs2_ail1_flush - start writeback of some ail1 entries
 138  * @sdp: The super block
 139  * @wbc: The writeback control structure
 140  *
 141  * Writes back some ail1 entries, according to the limits in the
 142  * writeback control structure
 143  */
 144
 145 void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc)
 146 {
 147         struct list_head *head = &sdp->sd_ail1_list;
 148         struct gfs2_ail *ai;
 149
 150         trace_gfs2_ail_flush(sdp, wbc, 1);
 151         spin_lock(&sdp->sd_ail_lock);
 152 restart:
 153         list_for_each_entry_reverse(ai, head, ai_list) {
 154                 if (wbc->nr_to_write <= 0)
 155                         break;
 156                 if (gfs2_ail1_start_one(sdp, wbc, ai))
 157                         goto restart;
 158         }
 159         spin_unlock(&sdp->sd_ail_lock);
 160         trace_gfs2_ail_flush(sdp, wbc, 0);
 161 }
 162
 163 /**
 164  * gfs2_ail1_start - start writeback of all ail1 entries
 165  * @sdp: The superblock
 166  */
 167
 168 static void gfs2_ail1_start(struct gfs2_sbd *sdp)
 169 {
 170         struct writeback_control wbc = {
 171                 .sync_mode = WB_SYNC_NONE,
 172                 .nr_to_write = LONG_MAX,
 173                 .range_start = 0,
 174                 .range_end = LLONG_MAX,
 175         };
 176
 177         return gfs2_ail1_flush(sdp, &wbc);
 178 }
 179
 180 /**
 181  * gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
 182  * @sdp: the filesystem
 183  * @ai: the AIL entry
 184  *
 185  */
 186
 187 static void gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
 188 {
 189         struct gfs2_bufdata *bd, *s;
 190         struct buffer_head *bh;
 191
 192         list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
 193                                          bd_ail_st_list) {
 194                 bh = bd->bd_bh;
 195                 gfs2_assert(sdp, bd->bd_ail == ai);
 196                 if (buffer_busy(bh))
 197                         continue;
 198                 if (!buffer_uptodate(bh))
 199                         gfs2_io_error_bh(sdp, bh);
 200                 list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
 201         }
 202
 203 }
 204
 205 /**
 206  * gfs2_ail1_empty - Try to empty the ail1 lists
 207  * @sdp: The superblock
 208  *
 209  * Tries to empty the ail1 lists, starting with the oldest first
 210  */
 211
 212 static int gfs2_ail1_empty(struct gfs2_sbd *sdp)
 213 {
 214         struct gfs2_ail *ai, *s;
 215         int ret;
 216
 217         spin_lock(&sdp->sd_ail_lock);
 218         list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) {
 219                 gfs2_ail1_empty_one(sdp, ai);
 220                 if (list_empty(&ai->ai_ail1_list))
 221                         list_move(&ai->ai_list, &sdp->sd_ail2_list);
 222                 else
 223                         break;
 224         }
 225         ret = list_empty(&sdp->sd_ail1_list);
 226         spin_unlock(&sdp->sd_ail_lock);
 227
 228         return ret;
 229 }
 230
 231 static void gfs2_ail1_wait(struct gfs2_sbd *sdp)
 232 {
 233         struct gfs2_ail *ai;
 234         struct gfs2_bufdata *bd;
 235         struct buffer_head *bh;
 236
 237         spin_lock(&sdp->sd_ail_lock);
 238         list_for_each_entry_reverse(ai, &sdp->sd_ail1_list, ai_list) {
 239                 list_for_each_entry(bd, &ai->ai_ail1_list, bd_ail_st_list) {
 240                         bh = bd->bd_bh;
 241                         if (!buffer_locked(bh))
 242                                 continue;
 243                         get_bh(bh);
 244                         spin_unlock(&sdp->sd_ail_lock);
 245                         wait_on_buffer(bh);
 246                         brelse(bh);
 247                         return;
 248                 }
 249         }
 250         spin_unlock(&sdp->sd_ail_lock);
 251 }
 252
 253 /**
 254  * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced
 255  * @sdp: the filesystem
 256  * @ai: the AIL entry
 257  *
 258  */
 259
 260 static void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
 261 {
 262         struct list_head *head = &ai->ai_ail2_list;
 263         struct gfs2_bufdata *bd;
 264
 265         while (!list_empty(head)) {
 266                 bd = list_entry(head->prev, struct gfs2_bufdata,
 267                                 bd_ail_st_list);
 268                 gfs2_assert(sdp, bd->bd_ail == ai);
 269                 gfs2_remove_from_ail(bd);
 270         }
 271 }
 272
 273 static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
 274 {
 275         struct gfs2_ail *ai, *safe;
 276         unsigned int old_tail = sdp->sd_log_tail;
 277         int wrap = (new_tail < old_tail);
 278         int a, b, rm;
 279
 280         spin_lock(&sdp->sd_ail_lock);
 281
 282         list_for_each_entry_safe(ai, safe, &sdp->sd_ail2_list, ai_list) {
 283                 a = (old_tail <= ai->ai_first);
 284                 b = (ai->ai_first < new_tail);
 285                 rm = (wrap) ? (a || b) : (a && b);
 286                 if (!rm)
 287                         continue;
 288
 289                 gfs2_ail2_empty_one(sdp, ai);
 290                 list_del(&ai->ai_list);
 291                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail1_list));
 292                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail2_list));
 293                 kfree(ai);
 294         }
 295
 296         spin_unlock(&sdp->sd_ail_lock);
 297 }
 298
 299 /**
 300  * gfs2_log_reserve - Make a log reservation
 301  * @sdp: The GFS2 superblock
 302  * @blks: The number of blocks to reserve
 303  *
 304  * Note that we never give out the last few blocks of the journal. Thats
 305  * due to the fact that there is a small number of header blocks
 306  * associated with each log flush. The exact number can't be known until
 307  * flush time, so we ensure that we have just enough free blocks at all
 308  * times to avoid running out during a log flush.
 309  *
 310  * We no longer flush the log here, instead we wake up logd to do that
 311  * for us. To avoid the thundering herd and to ensure that we deal fairly
 312  * with queued waiters, we use an exclusive wait. This means that when we
 313  * get woken with enough journal space to get our reservation, we need to
 314  * wake the next waiter on the list.
 315  *
 316  * Returns: errno
 317  */
 318
 319 int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 320 {
 321         unsigned reserved_blks = 6 * (4096 / sdp->sd_vfs->s_blocksize);
 322         unsigned wanted = blks + reserved_blks;
 323         DEFINE_WAIT(wait);
 324         int did_wait = 0;
 325         unsigned int free_blocks;
 326
 327         if (gfs2_assert_warn(sdp, blks) ||
 328             gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
 329                 return -EINVAL;
 330 retry:
 331         free_blocks = atomic_read(&sdp->sd_log_blks_free);
 332         if (unlikely(free_blocks <= wanted)) {
 333                 do {
 334                         prepare_to_wait_exclusive(&sdp->sd_log_waitq, &wait,
 335                                         TASK_UNINTERRUPTIBLE);
 336                         wake_up(&sdp->sd_logd_waitq);
 337                         did_wait = 1;
 338                         if (atomic_read(&sdp->sd_log_blks_free) <= wanted)
 339                                 io_schedule();
 340                         free_blocks = atomic_read(&sdp->sd_log_blks_free);
 341                 } while(free_blocks <= wanted);
 342                 finish_wait(&sdp->sd_log_waitq, &wait);
 343         }
 344         if (atomic_cmpxchg(&sdp->sd_log_blks_free, free_blocks,
 345                                 free_blocks - blks) != free_blocks)
 346                 goto retry;
 347         trace_gfs2_log_blocks(sdp, -blks);
 348
 349         /*
 350          * If we waited, then so might others, wake them up _after_ we get
 351          * our share of the log.
 352          */
 353         if (unlikely(did_wait))
 354                 wake_up(&sdp->sd_log_waitq);
 355
 356         down_read(&sdp->sd_log_flush_lock);
 357
 358         return 0;
 359 }
 360
 361 static u64 log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
 362 {
 363         struct gfs2_journal_extent *je;
 364
 365         list_for_each_entry(je, &sdp->sd_jdesc->extent_list, extent_list) {
 366                 if (lbn >= je->lblock && lbn < je->lblock + je->blocks)
 367                         return je->dblock + lbn - je->lblock;
 368         }
 369
 370         return -1;
 371 }
 372
 373 /**
 374  * log_distance - Compute distance between two journal blocks
 375  * @sdp: The GFS2 superblock
 376  * @newer: The most recent journal block of the pair
 377  * @older: The older journal block of the pair
 378  *
 379  *   Compute the distance (in the journal direction) between two
 380  *   blocks in the journal
 381  *
 382  * Returns: the distance in blocks
 383  */
 384
 385 static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer,
 386                                         unsigned int older)
 387 {
 388         int dist;
 389
 390         dist = newer - older;
 391         if (dist < 0)
 392                 dist += sdp->sd_jdesc->jd_blocks;
 393
 394         return dist;
 395 }
 396
 397 /**
 398  * calc_reserved - Calculate the number of blocks to reserve when
 399  *                 refunding a transaction's unused buffers.
 400  * @sdp: The GFS2 superblock
 401  *
 402  * This is complex.  We need to reserve room for all our currently used
 403  * metadata buffers (e.g. normal file I/O rewriting file time stamps) and
 404  * all our journaled data buffers for journaled files (e.g. files in the
 405  * meta_fs like rindex, or files for which chattr +j was done.)
 406  * If we don't reserve enough space, gfs2_log_refund and gfs2_log_flush
 407  * will count it as free space (sd_log_blks_free) and corruption will follow.
 408  *
 409  * We can have metadata bufs and jdata bufs in the same journal.  So each
 410  * type gets its own log header, for which we need to reserve a block.
 411  * In fact, each type has the potential for needing more than one header
 412  * in cases where we have more buffers than will fit on a journal page.
 413  * Metadata journal entries take up half the space of journaled buffer entries.
 414  * Thus, metadata entries have buf_limit (502) and journaled buffers have
 415  * databuf_limit (251) before they cause a wrap around.
 416  *
 417  * Also, we need to reserve blocks for revoke journal entries and one for an
 418  * overall header for the lot.
 419  *
 420  * Returns: the number of blocks reserved
 421  */
 422 static unsigned int calc_reserved(struct gfs2_sbd *sdp)
 423 {
 424         unsigned int reserved = 0;
 425         unsigned int mbuf_limit, metabufhdrs_needed;
 426         unsigned int dbuf_limit, databufhdrs_needed;
 427         unsigned int revokes = 0;
 428
 429         mbuf_limit = buf_limit(sdp);
 430         metabufhdrs_needed = (sdp->sd_log_commited_buf +
 431                               (mbuf_limit - 1)) / mbuf_limit;
 432         dbuf_limit = databuf_limit(sdp);
 433         databufhdrs_needed = (sdp->sd_log_commited_databuf +
 434                               (dbuf_limit - 1)) / dbuf_limit;
 435
 436         if (sdp->sd_log_commited_revoke > 0)
 437                 revokes = gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
 438                                           sizeof(u64));
 439
 440         reserved = sdp->sd_log_commited_buf + metabufhdrs_needed +
 441                 sdp->sd_log_commited_databuf + databufhdrs_needed +
 442                 revokes;
 443         /* One for the overall header */
 444         if (reserved)
 445                 reserved++;
 446         return reserved;
 447 }
 448
 449 static unsigned int current_tail(struct gfs2_sbd *sdp)
 450 {
 451         struct gfs2_ail *ai;
 452         unsigned int tail;
 453
 454         spin_lock(&sdp->sd_ail_lock);
 455
 456         if (list_empty(&sdp->sd_ail1_list)) {
 457                 tail = sdp->sd_log_head;
 458         } else {
 459                 ai = list_entry(sdp->sd_ail1_list.prev, struct gfs2_ail, ai_list);
 460                 tail = ai->ai_first;
 461         }
 462
 463         spin_unlock(&sdp->sd_ail_lock);
 464
 465         return tail;
 466 }
 467
 468 void gfs2_log_incr_head(struct gfs2_sbd *sdp)
 469 {
 470         if (sdp->sd_log_flush_head == sdp->sd_log_tail)
 471                 BUG_ON(sdp->sd_log_flush_head != sdp->sd_log_head);
 472
 473         if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
 474                 sdp->sd_log_flush_head = 0;
 475                 sdp->sd_log_flush_wrapped = 1;
 476         }
 477 }
 478
 479 /**
 480  * gfs2_log_write_endio - End of I/O for a log buffer
 481  * @bh: The buffer head
 482  * @uptodate: I/O Status
 483  *
 484  */
 485
 486 static void gfs2_log_write_endio(struct buffer_head *bh, int uptodate)
 487 {
 488         struct gfs2_sbd *sdp = bh->b_private;
 489         bh->b_private = NULL;
 490
 491         end_buffer_write_sync(bh, uptodate);
 492         if (atomic_dec_and_test(&sdp->sd_log_in_flight))
 493                 wake_up(&sdp->sd_log_flush_wait);
 494 }
 495
 496 /**
 497  * gfs2_log_get_buf - Get and initialize a buffer to use for log control data
 498  * @sdp: The GFS2 superblock
 499  *
 500  * Returns: the buffer_head
 501  */
 502
 503 struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
 504 {
 505         u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 506         struct buffer_head *bh;
 507
 508         bh = sb_getblk(sdp->sd_vfs, blkno);
 509         lock_buffer(bh);
 510         memset(bh->b_data, 0, bh->b_size);
 511         set_buffer_uptodate(bh);
 512         clear_buffer_dirty(bh);
 513         gfs2_log_incr_head(sdp);
 514         atomic_inc(&sdp->sd_log_in_flight);
 515         bh->b_private = sdp;
 516         bh->b_end_io = gfs2_log_write_endio;
 517
 518         return bh;
 519 }
 520
 521 /**
 522  * gfs2_fake_write_endio -
 523  * @bh: The buffer head
 524  * @uptodate: The I/O Status
 525  *
 526  */
 527
 528 static void gfs2_fake_write_endio(struct buffer_head *bh, int uptodate)
 529 {
 530         struct buffer_head *real_bh = bh->b_private;
 531         struct gfs2_bufdata *bd = real_bh->b_private;
 532         struct gfs2_sbd *sdp = bd->bd_gl->gl_sbd;
 533
 534         end_buffer_write_sync(bh, uptodate);
 535         free_buffer_head(bh);
 536         unlock_buffer(real_bh);
 537         brelse(real_bh);
 538         if (atomic_dec_and_test(&sdp->sd_log_in_flight))
 539                 wake_up(&sdp->sd_log_flush_wait);
 540 }
 541
 542 /**
 543  * gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
 544  * @sdp: the filesystem
 545  * @data: the data the buffer_head should point to
 546  *
 547  * Returns: the log buffer descriptor
 548  */
 549
 550 struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
 551                                       struct buffer_head *real)
 552 {
 553         u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 554         struct buffer_head *bh;
 555
 556         bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
 557         atomic_set(&bh->b_count, 1);
 558         bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate) | (1 << BH_Lock);
 559         set_bh_page(bh, real->b_page, bh_offset(real));
 560         bh->b_blocknr = blkno;
 561         bh->b_size = sdp->sd_sb.sb_bsize;
 562         bh->b_bdev = sdp->sd_vfs->s_bdev;
 563         bh->b_private = real;
 564         bh->b_end_io = gfs2_fake_write_endio;
 565
 566         gfs2_log_incr_head(sdp);
 567         atomic_inc(&sdp->sd_log_in_flight);
 568
 569         return bh;
 570 }
 571
 572 static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
 573 {
 574         unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
 575
 576         ail2_empty(sdp, new_tail);
 577
 578         atomic_add(dist, &sdp->sd_log_blks_free);
 579         trace_gfs2_log_blocks(sdp, dist);
 580         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 581                              sdp->sd_jdesc->jd_blocks);
 582
 583         sdp->sd_log_tail = new_tail;
 584 }
 585
 586 /**
 587  * log_write_header - Get and initialize a journal header buffer
 588  * @sdp: The GFS2 superblock
 589  *
 590  * Returns: the initialized log buffer descriptor
 591  */
 592
 593 static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)
 594 {
 595         u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
 596         struct buffer_head *bh;
 597         struct gfs2_log_header *lh;
 598         unsigned int tail;
 599         u32 hash;
 600
 601         bh = sb_getblk(sdp->sd_vfs, blkno);
 602         lock_buffer(bh);
 603         memset(bh->b_data, 0, bh->b_size);
 604         set_buffer_uptodate(bh);
 605         clear_buffer_dirty(bh);
 606
 607         gfs2_ail1_empty(sdp);
 608         tail = current_tail(sdp);
 609
 610         lh = (struct gfs2_log_header *)bh->b_data;
 611         memset(lh, 0, sizeof(struct gfs2_log_header));
 612         lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
 613         lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
 614         lh->lh_header.__pad0 = cpu_to_be64(0);
 615         lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
 616         lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
 617         lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++);
 618         lh->lh_flags = cpu_to_be32(flags);
 619         lh->lh_tail = cpu_to_be32(tail);
 620         lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head);
 621         hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));
 622         lh->lh_hash = cpu_to_be32(hash);
 623
 624         bh->b_end_io = end_buffer_write_sync;
 625         get_bh(bh);
 626         if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
 627                 submit_bh(WRITE_SYNC | REQ_META, bh);
 628         else
 629                 submit_bh(WRITE_FLUSH_FUA | REQ_META, bh);
 630         wait_on_buffer(bh);
 631
 632         if (!buffer_uptodate(bh))
 633                 gfs2_io_error_bh(sdp, bh);
 634         brelse(bh);
 635
 636         if (sdp->sd_log_tail != tail)
 637                 log_pull_tail(sdp, tail);
 638         else
 639                 gfs2_assert_withdraw(sdp, !pull);
 640
 641         sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
 642         gfs2_log_incr_head(sdp);
 643 }
 644
 645 static void log_flush_commit(struct gfs2_sbd *sdp)
 646 {
 647         DEFINE_WAIT(wait);
 648
 649         if (atomic_read(&sdp->sd_log_in_flight)) {
 650                 do {
 651                         prepare_to_wait(&sdp->sd_log_flush_wait, &wait,
 652                                         TASK_UNINTERRUPTIBLE);
 653                         if (atomic_read(&sdp->sd_log_in_flight))
 654                                 io_schedule();
 655                 } while(atomic_read(&sdp->sd_log_in_flight));
 656                 finish_wait(&sdp->sd_log_flush_wait, &wait);
 657         }
 658
 659         log_write_header(sdp, 0, 0);
 660 }
 661
 662 static void gfs2_ordered_write(struct gfs2_sbd *sdp)
 663 {
 664         struct gfs2_bufdata *bd;
 665         struct buffer_head *bh;
 666         LIST_HEAD(written);
 667
 668         gfs2_log_lock(sdp);
 669         while (!list_empty(&sdp->sd_log_le_ordered)) {
 670                 bd = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_bufdata, bd_le.le_list);
 671                 list_move(&bd->bd_le.le_list, &written);
 672                 bh = bd->bd_bh;
 673                 if (!buffer_dirty(bh))
 674                         continue;
 675                 get_bh(bh);
 676                 gfs2_log_unlock(sdp);
 677                 lock_buffer(bh);
 678                 if (buffer_mapped(bh) && test_clear_buffer_dirty(bh)) {
 679                         bh->b_end_io = end_buffer_write_sync;
 680                         submit_bh(WRITE_SYNC, bh);
 681                 } else {
 682                         unlock_buffer(bh);
 683                         brelse(bh);
 684                 }
 685                 gfs2_log_lock(sdp);
 686         }
 687         list_splice(&written, &sdp->sd_log_le_ordered);
 688         gfs2_log_unlock(sdp);
 689 }
 690
 691 static void gfs2_ordered_wait(struct gfs2_sbd *sdp)
 692 {
 693         struct gfs2_bufdata *bd;
 694         struct buffer_head *bh;
 695
 696         gfs2_log_lock(sdp);
 697         while (!list_empty(&sdp->sd_log_le_ordered)) {
 698                 bd = list_entry(sdp->sd_log_le_ordered.prev, struct gfs2_bufdata, bd_le.le_list);
 699                 bh = bd->bd_bh;
 700                 if (buffer_locked(bh)) {
 701                         get_bh(bh);
 702                         gfs2_log_unlock(sdp);
 703                         wait_on_buffer(bh);
 704                         brelse(bh);
 705                         gfs2_log_lock(sdp);
 706                         continue;
 707                 }
 708                 list_del_init(&bd->bd_le.le_list);
 709         }
 710         gfs2_log_unlock(sdp);
 711 }
 712
 713 /**
 714  * gfs2_log_flush - flush incore transaction(s)
 715  * @sdp: the filesystem
 716  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
 717  *
 718  */
 719
 720 void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 721 {
 722         struct gfs2_ail *ai;
 723
 724         down_write(&sdp->sd_log_flush_lock);
 725
 726         /* Log might have been flushed while we waited for the flush lock */
 727         if (gl && !test_bit(GLF_LFLUSH, &gl->gl_flags)) {
 728                 up_write(&sdp->sd_log_flush_lock);
 729                 return;
 730         }
 731         trace_gfs2_log_flush(sdp, 1);
 732
 733         ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
 734         INIT_LIST_HEAD(&ai->ai_ail1_list);
 735         INIT_LIST_HEAD(&ai->ai_ail2_list);
 736
 737         if (sdp->sd_log_num_buf != sdp->sd_log_commited_buf) {
 738                 printk(KERN_INFO "GFS2: log buf %u %u\n", sdp->sd_log_num_buf,
 739                        sdp->sd_log_commited_buf);
 740                 gfs2_assert_withdraw(sdp, 0);
 741         }
 742         if (sdp->sd_log_num_databuf != sdp->sd_log_commited_databuf) {
 743                 printk(KERN_INFO "GFS2: log databuf %u %u\n",
 744                        sdp->sd_log_num_databuf, sdp->sd_log_commited_databuf);
 745                 gfs2_assert_withdraw(sdp, 0);
 746         }
 747         gfs2_assert_withdraw(sdp,
 748                         sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
 749
 750         sdp->sd_log_flush_head = sdp->sd_log_head;
 751         sdp->sd_log_flush_wrapped = 0;
 752         ai->ai_first = sdp->sd_log_flush_head;
 753
 754         gfs2_ordered_write(sdp);
 755         lops_before_commit(sdp);
 756         gfs2_ordered_wait(sdp);
 757
 758         if (sdp->sd_log_head != sdp->sd_log_flush_head)
 759                 log_flush_commit(sdp);
 760         else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
 761                 gfs2_log_lock(sdp);
 762                 atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
 763                 trace_gfs2_log_blocks(sdp, -1);
 764                 gfs2_log_unlock(sdp);
 765                 log_write_header(sdp, 0, PULL);
 766         }
 767         lops_after_commit(sdp, ai);
 768
 769         gfs2_log_lock(sdp);
 770         sdp->sd_log_head = sdp->sd_log_flush_head;
 771         sdp->sd_log_blks_reserved = 0;
 772         sdp->sd_log_commited_buf = 0;
 773         sdp->sd_log_commited_databuf = 0;
 774         sdp->sd_log_commited_revoke = 0;
 775
 776         spin_lock(&sdp->sd_ail_lock);
 777         if (!list_empty(&ai->ai_ail1_list)) {
 778                 list_add(&ai->ai_list, &sdp->sd_ail1_list);
 779                 ai = NULL;
 780         }
 781         spin_unlock(&sdp->sd_ail_lock);
 782         gfs2_log_unlock(sdp);
 783         trace_gfs2_log_flush(sdp, 0);
 784         up_write(&sdp->sd_log_flush_lock);
 785
 786         kfree(ai);
 787 }
 788
 789 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 790 {
 791         unsigned int reserved;
 792         unsigned int unused;
 793
 794         gfs2_log_lock(sdp);
 795
 796         sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
 797         sdp->sd_log_commited_databuf += tr->tr_num_databuf_new -
 798                 tr->tr_num_databuf_rm;
 799         gfs2_assert_withdraw(sdp, (((int)sdp->sd_log_commited_buf) >= 0) ||
 800                              (((int)sdp->sd_log_commited_databuf) >= 0));
 801         sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
 802         reserved = calc_reserved(sdp);
 803         gfs2_assert_withdraw(sdp, sdp->sd_log_blks_reserved + tr->tr_reserved >= reserved);
 804         unused = sdp->sd_log_blks_reserved - reserved + tr->tr_reserved;
 805         atomic_add(unused, &sdp->sd_log_blks_free);
 806         trace_gfs2_log_blocks(sdp, unused);
 807         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 808                              sdp->sd_jdesc->jd_blocks);
 809         sdp->sd_log_blks_reserved = reserved;
 810
 811         gfs2_log_unlock(sdp);
 812 }
 813
 814 static void buf_lo_incore_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 815 {
 816         struct list_head *head = &tr->tr_list_buf;
 817         struct gfs2_bufdata *bd;
 818
 819         gfs2_log_lock(sdp);
 820         while (!list_empty(head)) {
 821                 bd = list_entry(head->next, struct gfs2_bufdata, bd_list_tr);
 822                 list_del_init(&bd->bd_list_tr);
 823                 tr->tr_num_buf--;
 824         }
 825         gfs2_log_unlock(sdp);
 826         gfs2_assert_warn(sdp, !tr->tr_num_buf);
 827 }
 828
 829 /**
 830  * gfs2_log_commit - Commit a transaction to the log
 831  * @sdp: the filesystem
 832  * @tr: the transaction
 833  *
 834  * We wake up gfs2_logd if the number of pinned blocks exceed thresh1
 835  * or the total number of used blocks (pinned blocks plus AIL blocks)
 836  * is greater than thresh2.
 837  *
 838  * At mount time thresh1 is 1/3rd of journal size, thresh2 is 2/3rd of
 839  * journal size.
 840  *
 841  * Returns: errno
 842  */
 843
 844 void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 845 {
 846         log_refund(sdp, tr);
 847         buf_lo_incore_commit(sdp, tr);
 848
 849         up_read(&sdp->sd_log_flush_lock);
 850
 851         if (atomic_read(&sdp->sd_log_pinned) > atomic_read(&sdp->sd_log_thresh1) ||
 852             ((sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free)) >
 853             atomic_read(&sdp->sd_log_thresh2)))
 854                 wake_up(&sdp->sd_logd_waitq);
 855 }
 856
 857 /**
 858  * gfs2_log_shutdown - write a shutdown header into a journal
 859  * @sdp: the filesystem
 860  *
 861  */
 862
 863 void gfs2_log_shutdown(struct gfs2_sbd *sdp)
 864 {
 865         down_write(&sdp->sd_log_flush_lock);
 866
 867         gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
 868         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf);
 869         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
 870         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
 871         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
 872         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
 873
 874         sdp->sd_log_flush_head = sdp->sd_log_head;
 875         sdp->sd_log_flush_wrapped = 0;
 876
 877         log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT,
 878                          (sdp->sd_log_tail == current_tail(sdp)) ? 0 : PULL);
 879
 880         gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks);
 881         gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
 882         gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
 883
 884         sdp->sd_log_head = sdp->sd_log_flush_head;
 885         sdp->sd_log_tail = sdp->sd_log_head;
 886
 887         up_write(&sdp->sd_log_flush_lock);
 888 }
 889
 890
 891 /**
 892  * gfs2_meta_syncfs - sync all the buffers in a filesystem
 893  * @sdp: the filesystem
 894  *
 895  */
 896
 897 void gfs2_meta_syncfs(struct gfs2_sbd *sdp)
 898 {
 899         gfs2_log_flush(sdp, NULL);
 900         for (;;) {
 901                 gfs2_ail1_start(sdp);
 902                 gfs2_ail1_wait(sdp);
 903                 if (gfs2_ail1_empty(sdp))
 904                         break;
 905         }
 906         gfs2_log_flush(sdp, NULL);
 907 }
 908
 909 static inline int gfs2_jrnl_flush_reqd(struct gfs2_sbd *sdp)
 910 {
 911         return (atomic_read(&sdp->sd_log_pinned) >= atomic_read(&sdp->sd_log_thresh1));
 912 }
 913
 914 static inline int gfs2_ail_flush_reqd(struct gfs2_sbd *sdp)
 915 {
 916         unsigned int used_blocks = sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free);
 917         return used_blocks >= atomic_read(&sdp->sd_log_thresh2);
 918 }
 919
 920 /**
 921  * gfs2_logd - Update log tail as Active Items get flushed to in-place blocks
 922  * @sdp: Pointer to GFS2 superblock
 923  *
 924  * Also, periodically check to make sure that we're using the most recent
 925  * journal index.
 926  */
 927
 928 int gfs2_logd(void *data)
 929 {
 930         struct gfs2_sbd *sdp = data;
 931         unsigned long t = 1;
 932         DEFINE_WAIT(wait);
 933         unsigned preflush;
 934
 935         while (!kthread_should_stop()) {
 936
 937                 preflush = atomic_read(&sdp->sd_log_pinned);
 938                 if (gfs2_jrnl_flush_reqd(sdp) || t == 0) {
 939                         gfs2_ail1_empty(sdp);
 940                         gfs2_log_flush(sdp, NULL);
 941                 }
 942
 943                 if (gfs2_ail_flush_reqd(sdp)) {
 944                         gfs2_ail1_start(sdp);
 945                         gfs2_ail1_wait(sdp);
 946                         gfs2_ail1_empty(sdp);
 947                         gfs2_log_flush(sdp, NULL);
 948                 }
 949
 950                 if (!gfs2_ail_flush_reqd(sdp))
 951                         wake_up(&sdp->sd_log_waitq);
 952
 953                 t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
 954                 if (freezing(current))
 955                         refrigerator();
 956
 957                 do {
 958                         prepare_to_wait(&sdp->sd_logd_waitq, &wait,
 959                                         TASK_INTERRUPTIBLE);
 960                         if (!gfs2_ail_flush_reqd(sdp) &&
 961                             !gfs2_jrnl_flush_reqd(sdp) &&
 962                             !kthread_should_stop())
 963                                 t = schedule_timeout(t);
 964                 } while(t && !gfs2_ail_flush_reqd(sdp) &&
 965                         !gfs2_jrnl_flush_reqd(sdp) &&
 966                         !kthread_should_stop());
 967                 finish_wait(&sdp->sd_logd_waitq, &wait);
 968         }
 969
 970         return 0;
 971 }
 972