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 #include <linux/list_sort.h>
  23
  24 #include "gfs2.h"
  25 #include "incore.h"
  26 #include "bmap.h"
  27 #include "glock.h"
  28 #include "log.h"
  29 #include "lops.h"
  30 #include "meta_io.h"
  31 #include "util.h"
  32 #include "dir.h"
  33 #include "trace_gfs2.h"
  34
  35 #define PULL 1
  36
  37 /**
  38  * gfs2_struct2blk - compute stuff
  39  * @sdp: the filesystem
  40  * @nstruct: the number of structures
  41  * @ssize: the size of the structures
  42  *
  43  * Compute the number of log descriptor blocks needed to hold a certain number
  44  * of structures of a certain size.
  45  *
  46  * Returns: the number of blocks needed (minimum is always 1)
  47  */
  48
  49 unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct,
  50                              unsigned int ssize)
  51 {
  52         unsigned int blks;
  53         unsigned int first, second;
  54
  55         blks = 1;
  56         first = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) / ssize;
  57
  58         if (nstruct > first) {
  59                 second = (sdp->sd_sb.sb_bsize -
  60                           sizeof(struct gfs2_meta_header)) / ssize;
  61                 blks += DIV_ROUND_UP(nstruct - first, second);
  62         }
  63
  64         return blks;
  65 }
  66
  67 /**
  68  * gfs2_remove_from_ail - Remove an entry from the ail lists, updating counters
  69  * @mapping: The associated mapping (maybe NULL)
  70  * @bd: The gfs2_bufdata to remove
  71  *
  72  * The ail lock _must_ be held when calling this function
  73  *
  74  */
  75
  76 void gfs2_remove_from_ail(struct gfs2_bufdata *bd)
  77 {
  78         bd->bd_ail = NULL;
  79         list_del_init(&bd->bd_ail_st_list);
  80         list_del_init(&bd->bd_ail_gl_list);
  81         atomic_dec(&bd->bd_gl->gl_ail_count);
  82         brelse(bd->bd_bh);
  83 }
  84
  85 /**
  86  * gfs2_ail1_start_one - Start I/O on a part of the AIL
  87  * @sdp: the filesystem
  88  * @wbc: The writeback control structure
  89  * @ai: The ail structure
  90  *
  91  */
  92
  93 static int gfs2_ail1_start_one(struct gfs2_sbd *sdp,
  94                                struct writeback_control *wbc,
  95                                struct gfs2_ail *ai)
  96 __releases(&sdp->sd_ail_lock)
  97 __acquires(&sdp->sd_ail_lock)
  98 {
  99         struct gfs2_glock *gl = NULL;
 100         struct address_space *mapping;
 101         struct gfs2_bufdata *bd, *s;
 102         struct buffer_head *bh;
 103
 104         list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list, bd_ail_st_list) {
 105                 bh = bd->bd_bh;
 106
 107                 gfs2_assert(sdp, bd->bd_ail == ai);
 108
 109                 if (!buffer_busy(bh)) {
 110                         if (!buffer_uptodate(bh))
 111                                 gfs2_io_error_bh(sdp, bh);
 112                         list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
 113                         continue;
 114                 }
 115
 116                 if (!buffer_dirty(bh))
 117                         continue;
 118                 if (gl == bd->bd_gl)
 119                         continue;
 120                 gl = bd->bd_gl;
 121                 list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list);
 122                 mapping = bh->b_page->mapping;
 123                 if (!mapping)
 124                         continue;
 125                 spin_unlock(&sdp->sd_ail_lock);
 126                 generic_writepages(mapping, wbc);
 127                 spin_lock(&sdp->sd_ail_lock);
 128                 if (wbc->nr_to_write <= 0)
 129                         break;
 130                 return 1;
 131         }
 132
 133         return 0;
 134 }
 135
 136
 137 /**
 138  * gfs2_ail1_flush - start writeback of some ail1 entries
 139  * @sdp: The super block
 140  * @wbc: The writeback control structure
 141  *
 142  * Writes back some ail1 entries, according to the limits in the
 143  * writeback control structure
 144  */
 145
 146 void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc)
 147 {
 148         struct list_head *head = &sdp->sd_ail1_list;
 149         struct gfs2_ail *ai;
 150
 151         trace_gfs2_ail_flush(sdp, wbc, 1);
 152         spin_lock(&sdp->sd_ail_lock);
 153 restart:
 154         list_for_each_entry_reverse(ai, head, ai_list) {
 155                 if (wbc->nr_to_write <= 0)
 156                         break;
 157                 if (gfs2_ail1_start_one(sdp, wbc, ai))
 158                         goto restart;
 159         }
 160         spin_unlock(&sdp->sd_ail_lock);
 161         trace_gfs2_ail_flush(sdp, wbc, 0);
 162 }
 163
 164 /**
 165  * gfs2_ail1_start - start writeback of all ail1 entries
 166  * @sdp: The superblock
 167  */
 168
 169 static void gfs2_ail1_start(struct gfs2_sbd *sdp)
 170 {
 171         struct writeback_control wbc = {
 172                 .sync_mode = WB_SYNC_NONE,
 173                 .nr_to_write = LONG_MAX,
 174                 .range_start = 0,
 175                 .range_end = LLONG_MAX,
 176         };
 177
 178         return gfs2_ail1_flush(sdp, &wbc);
 179 }
 180
 181 /**
 182  * gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
 183  * @sdp: the filesystem
 184  * @ai: the AIL entry
 185  *
 186  */
 187
 188 static void gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
 189 {
 190         struct gfs2_bufdata *bd, *s;
 191         struct buffer_head *bh;
 192
 193         list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
 194                                          bd_ail_st_list) {
 195                 bh = bd->bd_bh;
 196                 gfs2_assert(sdp, bd->bd_ail == ai);
 197                 if (buffer_busy(bh))
 198                         continue;
 199                 if (!buffer_uptodate(bh))
 200                         gfs2_io_error_bh(sdp, bh);
 201                 list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
 202         }
 203
 204 }
 205
 206 /**
 207  * gfs2_ail1_empty - Try to empty the ail1 lists
 208  * @sdp: The superblock
 209  *
 210  * Tries to empty the ail1 lists, starting with the oldest first
 211  */
 212
 213 static int gfs2_ail1_empty(struct gfs2_sbd *sdp)
 214 {
 215         struct gfs2_ail *ai, *s;
 216         int ret;
 217
 218         spin_lock(&sdp->sd_ail_lock);
 219         list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) {
 220                 gfs2_ail1_empty_one(sdp, ai);
 221                 if (list_empty(&ai->ai_ail1_list))
 222                         list_move(&ai->ai_list, &sdp->sd_ail2_list);
 223                 else
 224                         break;
 225         }
 226         ret = list_empty(&sdp->sd_ail1_list);
 227         spin_unlock(&sdp->sd_ail_lock);
 228
 229         return ret;
 230 }
 231
 232 static void gfs2_ail1_wait(struct gfs2_sbd *sdp)
 233 {
 234         struct gfs2_ail *ai;
 235         struct gfs2_bufdata *bd;
 236         struct buffer_head *bh;
 237
 238         spin_lock(&sdp->sd_ail_lock);
 239         list_for_each_entry_reverse(ai, &sdp->sd_ail1_list, ai_list) {
 240                 list_for_each_entry(bd, &ai->ai_ail1_list, bd_ail_st_list) {
 241                         bh = bd->bd_bh;
 242                         if (!buffer_locked(bh))
 243                                 continue;
 244                         get_bh(bh);
 245                         spin_unlock(&sdp->sd_ail_lock);
 246                         wait_on_buffer(bh);
 247                         brelse(bh);
 248                         return;
 249                 }
 250         }
 251         spin_unlock(&sdp->sd_ail_lock);
 252 }
 253
 254 /**
 255  * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced
 256  * @sdp: the filesystem
 257  * @ai: the AIL entry
 258  *
 259  */
 260
 261 static void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
 262 {
 263         struct list_head *head = &ai->ai_ail2_list;
 264         struct gfs2_bufdata *bd;
 265
 266         while (!list_empty(head)) {
 267                 bd = list_entry(head->prev, struct gfs2_bufdata,
 268                                 bd_ail_st_list);
 269                 gfs2_assert(sdp, bd->bd_ail == ai);
 270                 gfs2_remove_from_ail(bd);
 271         }
 272 }
 273
 274 static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
 275 {
 276         struct gfs2_ail *ai, *safe;
 277         unsigned int old_tail = sdp->sd_log_tail;
 278         int wrap = (new_tail < old_tail);
 279         int a, b, rm;
 280
 281         spin_lock(&sdp->sd_ail_lock);
 282
 283         list_for_each_entry_safe(ai, safe, &sdp->sd_ail2_list, ai_list) {
 284                 a = (old_tail <= ai->ai_first);
 285                 b = (ai->ai_first < new_tail);
 286                 rm = (wrap) ? (a || b) : (a && b);
 287                 if (!rm)
 288                         continue;
 289
 290                 gfs2_ail2_empty_one(sdp, ai);
 291                 list_del(&ai->ai_list);
 292                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail1_list));
 293                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail2_list));
 294                 kfree(ai);
 295         }
 296
 297         spin_unlock(&sdp->sd_ail_lock);
 298 }
 299
 300 /**
 301  * gfs2_log_reserve - Make a log reservation
 302  * @sdp: The GFS2 superblock
 303  * @blks: The number of blocks to reserve
 304  *
 305  * Note that we never give out the last few blocks of the journal. Thats
 306  * due to the fact that there is a small number of header blocks
 307  * associated with each log flush. The exact number can't be known until
 308  * flush time, so we ensure that we have just enough free blocks at all
 309  * times to avoid running out during a log flush.
 310  *
 311  * We no longer flush the log here, instead we wake up logd to do that
 312  * for us. To avoid the thundering herd and to ensure that we deal fairly
 313  * with queued waiters, we use an exclusive wait. This means that when we
 314  * get woken with enough journal space to get our reservation, we need to
 315  * wake the next waiter on the list.
 316  *
 317  * Returns: errno
 318  */
 319
 320 int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 321 {
 322         unsigned reserved_blks = 6 * (4096 / sdp->sd_vfs->s_blocksize);
 323         unsigned wanted = blks + reserved_blks;
 324         DEFINE_WAIT(wait);
 325         int did_wait = 0;
 326         unsigned int free_blocks;
 327
 328         if (gfs2_assert_warn(sdp, blks) ||
 329             gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
 330                 return -EINVAL;
 331 retry:
 332         free_blocks = atomic_read(&sdp->sd_log_blks_free);
 333         if (unlikely(free_blocks <= wanted)) {
 334                 do {
 335                         prepare_to_wait_exclusive(&sdp->sd_log_waitq, &wait,
 336                                         TASK_UNINTERRUPTIBLE);
 337                         wake_up(&sdp->sd_logd_waitq);
 338                         did_wait = 1;
 339                         if (atomic_read(&sdp->sd_log_blks_free) <= wanted)
 340                                 io_schedule();
 341                         free_blocks = atomic_read(&sdp->sd_log_blks_free);
 342                 } while(free_blocks <= wanted);
 343                 finish_wait(&sdp->sd_log_waitq, &wait);
 344         }
 345         if (atomic_cmpxchg(&sdp->sd_log_blks_free, free_blocks,
 346                                 free_blocks - blks) != free_blocks)
 347                 goto retry;
 348         trace_gfs2_log_blocks(sdp, -blks);
 349
 350         /*
 351          * If we waited, then so might others, wake them up _after_ we get
 352          * our share of the log.
 353          */
 354         if (unlikely(did_wait))
 355                 wake_up(&sdp->sd_log_waitq);
 356
 357         down_read(&sdp->sd_log_flush_lock);
 358
 359         return 0;
 360 }
 361
 362 u64 gfs2_log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
 363 {
 364         struct gfs2_journal_extent *je;
 365
 366         list_for_each_entry(je, &sdp->sd_jdesc->extent_list, extent_list) {
 367                 if (lbn >= je->lblock && lbn < je->lblock + je->blocks)
 368                         return je->dblock + lbn - je->lblock;
 369         }
 370
 371         return -1;
 372 }
 373
 374 /**
 375  * log_distance - Compute distance between two journal blocks
 376  * @sdp: The GFS2 superblock
 377  * @newer: The most recent journal block of the pair
 378  * @older: The older journal block of the pair
 379  *
 380  *   Compute the distance (in the journal direction) between two
 381  *   blocks in the journal
 382  *
 383  * Returns: the distance in blocks
 384  */
 385
 386 static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer,
 387                                         unsigned int older)
 388 {
 389         int dist;
 390
 391         dist = newer - older;
 392         if (dist < 0)
 393                 dist += sdp->sd_jdesc->jd_blocks;
 394
 395         return dist;
 396 }
 397
 398 /**
 399  * calc_reserved - Calculate the number of blocks to reserve when
 400  *                 refunding a transaction's unused buffers.
 401  * @sdp: The GFS2 superblock
 402  *
 403  * This is complex.  We need to reserve room for all our currently used
 404  * metadata buffers (e.g. normal file I/O rewriting file time stamps) and
 405  * all our journaled data buffers for journaled files (e.g. files in the
 406  * meta_fs like rindex, or files for which chattr +j was done.)
 407  * If we don't reserve enough space, gfs2_log_refund and gfs2_log_flush
 408  * will count it as free space (sd_log_blks_free) and corruption will follow.
 409  *
 410  * We can have metadata bufs and jdata bufs in the same journal.  So each
 411  * type gets its own log header, for which we need to reserve a block.
 412  * In fact, each type has the potential for needing more than one header
 413  * in cases where we have more buffers than will fit on a journal page.
 414  * Metadata journal entries take up half the space of journaled buffer entries.
 415  * Thus, metadata entries have buf_limit (502) and journaled buffers have
 416  * databuf_limit (251) before they cause a wrap around.
 417  *
 418  * Also, we need to reserve blocks for revoke journal entries and one for an
 419  * overall header for the lot.
 420  *
 421  * Returns: the number of blocks reserved
 422  */
 423 static unsigned int calc_reserved(struct gfs2_sbd *sdp)
 424 {
 425         unsigned int reserved = 0;
 426         unsigned int mbuf_limit, metabufhdrs_needed;
 427         unsigned int dbuf_limit, databufhdrs_needed;
 428         unsigned int revokes = 0;
 429
 430         mbuf_limit = buf_limit(sdp);
 431         metabufhdrs_needed = (sdp->sd_log_commited_buf +
 432                               (mbuf_limit - 1)) / mbuf_limit;
 433         dbuf_limit = databuf_limit(sdp);
 434         databufhdrs_needed = (sdp->sd_log_commited_databuf +
 435                               (dbuf_limit - 1)) / dbuf_limit;
 436
 437         if (sdp->sd_log_commited_revoke > 0)
 438                 revokes = gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
 439                                           sizeof(u64));
 440
 441         reserved = sdp->sd_log_commited_buf + metabufhdrs_needed +
 442                 sdp->sd_log_commited_databuf + databufhdrs_needed +
 443                 revokes;
 444         /* One for the overall header */
 445         if (reserved)
 446                 reserved++;
 447         return reserved;
 448 }
 449
 450 static unsigned int current_tail(struct gfs2_sbd *sdp)
 451 {
 452         struct gfs2_ail *ai;
 453         unsigned int tail;
 454
 455         spin_lock(&sdp->sd_ail_lock);
 456
 457         if (list_empty(&sdp->sd_ail1_list)) {
 458                 tail = sdp->sd_log_head;
 459         } else {
 460                 ai = list_entry(sdp->sd_ail1_list.prev, struct gfs2_ail, ai_list);
 461                 tail = ai->ai_first;
 462         }
 463
 464         spin_unlock(&sdp->sd_ail_lock);
 465
 466         return tail;
 467 }
 468
 469 void gfs2_log_incr_head(struct gfs2_sbd *sdp)
 470 {
 471         BUG_ON((sdp->sd_log_flush_head == sdp->sd_log_tail) &&
 472                (sdp->sd_log_flush_head != sdp->sd_log_head));
 473
 474         if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
 475                 sdp->sd_log_flush_head = 0;
 476                 sdp->sd_log_flush_wrapped = 1;
 477         }
 478 }
 479
 480 static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
 481 {
 482         unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
 483
 484         ail2_empty(sdp, new_tail);
 485
 486         atomic_add(dist, &sdp->sd_log_blks_free);
 487         trace_gfs2_log_blocks(sdp, dist);
 488         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 489                              sdp->sd_jdesc->jd_blocks);
 490
 491         sdp->sd_log_tail = new_tail;
 492 }
 493
 494
 495 static void log_flush_wait(struct gfs2_sbd *sdp)
 496 {
 497         DEFINE_WAIT(wait);
 498
 499         if (atomic_read(&sdp->sd_log_in_flight)) {
 500                 do {
 501                         prepare_to_wait(&sdp->sd_log_flush_wait, &wait,
 502                                         TASK_UNINTERRUPTIBLE);
 503                         if (atomic_read(&sdp->sd_log_in_flight))
 504                                 io_schedule();
 505                 } while(atomic_read(&sdp->sd_log_in_flight));
 506                 finish_wait(&sdp->sd_log_flush_wait, &wait);
 507         }
 508 }
 509
 510 static int bd_cmp(void *priv, struct list_head *a, struct list_head *b)
 511 {
 512         struct gfs2_bufdata *bda, *bdb;
 513
 514         bda = list_entry(a, struct gfs2_bufdata, bd_le.le_list);
 515         bdb = list_entry(b, struct gfs2_bufdata, bd_le.le_list);
 516
 517         if (bda->bd_bh->b_blocknr < bdb->bd_bh->b_blocknr)
 518                 return -1;
 519         if (bda->bd_bh->b_blocknr > bdb->bd_bh->b_blocknr)
 520                 return 1;
 521         return 0;
 522 }
 523
 524 static void gfs2_ordered_write(struct gfs2_sbd *sdp)
 525 {
 526         struct gfs2_bufdata *bd;
 527         struct buffer_head *bh;
 528         LIST_HEAD(written);
 529
 530         gfs2_log_lock(sdp);
 531         list_sort(NULL, &sdp->sd_log_le_ordered, &bd_cmp);
 532         while (!list_empty(&sdp->sd_log_le_ordered)) {
 533                 bd = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_bufdata, bd_le.le_list);
 534                 list_move(&bd->bd_le.le_list, &written);
 535                 bh = bd->bd_bh;
 536                 if (!buffer_dirty(bh))
 537                         continue;
 538                 get_bh(bh);
 539                 gfs2_log_unlock(sdp);
 540                 lock_buffer(bh);
 541                 if (buffer_mapped(bh) && test_clear_buffer_dirty(bh)) {
 542                         bh->b_end_io = end_buffer_write_sync;
 543                         submit_bh(WRITE_SYNC, bh);
 544                 } else {
 545                         unlock_buffer(bh);
 546                         brelse(bh);
 547                 }
 548                 gfs2_log_lock(sdp);
 549         }
 550         list_splice(&written, &sdp->sd_log_le_ordered);
 551         gfs2_log_unlock(sdp);
 552 }
 553
 554 static void gfs2_ordered_wait(struct gfs2_sbd *sdp)
 555 {
 556         struct gfs2_bufdata *bd;
 557         struct buffer_head *bh;
 558
 559         gfs2_log_lock(sdp);
 560         while (!list_empty(&sdp->sd_log_le_ordered)) {
 561                 bd = list_entry(sdp->sd_log_le_ordered.prev, struct gfs2_bufdata, bd_le.le_list);
 562                 bh = bd->bd_bh;
 563                 if (buffer_locked(bh)) {
 564                         get_bh(bh);
 565                         gfs2_log_unlock(sdp);
 566                         wait_on_buffer(bh);
 567                         brelse(bh);
 568                         gfs2_log_lock(sdp);
 569                         continue;
 570                 }
 571                 list_del_init(&bd->bd_le.le_list);
 572         }
 573         gfs2_log_unlock(sdp);
 574 }
 575
 576 /**
 577  * log_write_header - Get and initialize a journal header buffer
 578  * @sdp: The GFS2 superblock
 579  *
 580  * Returns: the initialized log buffer descriptor
 581  */
 582
 583 static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)
 584 {
 585         u64 blkno = gfs2_log_bmap(sdp, sdp->sd_log_flush_head);
 586         struct buffer_head *bh;
 587         struct gfs2_log_header *lh;
 588         unsigned int tail;
 589         u32 hash;
 590
 591         bh = sb_getblk(sdp->sd_vfs, blkno);
 592         lock_buffer(bh);
 593         memset(bh->b_data, 0, bh->b_size);
 594         set_buffer_uptodate(bh);
 595         clear_buffer_dirty(bh);
 596
 597         gfs2_ail1_empty(sdp);
 598         tail = current_tail(sdp);
 599
 600         lh = (struct gfs2_log_header *)bh->b_data;
 601         memset(lh, 0, sizeof(struct gfs2_log_header));
 602         lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
 603         lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
 604         lh->lh_header.__pad0 = cpu_to_be64(0);
 605         lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
 606         lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
 607         lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++);
 608         lh->lh_flags = cpu_to_be32(flags);
 609         lh->lh_tail = cpu_to_be32(tail);
 610         lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head);
 611         hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));
 612         lh->lh_hash = cpu_to_be32(hash);
 613
 614         bh->b_end_io = end_buffer_write_sync;
 615         get_bh(bh);
 616         if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) {
 617                 gfs2_ordered_wait(sdp);
 618                 log_flush_wait(sdp);
 619                 submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh);
 620         } else {
 621                 submit_bh(WRITE_FLUSH_FUA | REQ_META, bh);
 622         }
 623         wait_on_buffer(bh);
 624
 625         if (!buffer_uptodate(bh))
 626                 gfs2_io_error_bh(sdp, bh);
 627         brelse(bh);
 628
 629         if (sdp->sd_log_tail != tail)
 630                 log_pull_tail(sdp, tail);
 631         else
 632                 gfs2_assert_withdraw(sdp, !pull);
 633
 634         sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
 635         gfs2_log_incr_head(sdp);
 636 }
 637
 638 /**
 639  * gfs2_log_flush - flush incore transaction(s)
 640  * @sdp: the filesystem
 641  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
 642  *
 643  */
 644
 645 void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 646 {
 647         struct gfs2_ail *ai;
 648
 649         down_write(&sdp->sd_log_flush_lock);
 650
 651         /* Log might have been flushed while we waited for the flush lock */
 652         if (gl && !test_bit(GLF_LFLUSH, &gl->gl_flags)) {
 653                 up_write(&sdp->sd_log_flush_lock);
 654                 return;
 655         }
 656         trace_gfs2_log_flush(sdp, 1);
 657
 658         ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
 659         INIT_LIST_HEAD(&ai->ai_ail1_list);
 660         INIT_LIST_HEAD(&ai->ai_ail2_list);
 661
 662         if (sdp->sd_log_num_buf != sdp->sd_log_commited_buf) {
 663                 printk(KERN_INFO "GFS2: log buf %u %u\n", sdp->sd_log_num_buf,
 664                        sdp->sd_log_commited_buf);
 665                 gfs2_assert_withdraw(sdp, 0);
 666         }
 667         if (sdp->sd_log_num_databuf != sdp->sd_log_commited_databuf) {
 668                 printk(KERN_INFO "GFS2: log databuf %u %u\n",
 669                        sdp->sd_log_num_databuf, sdp->sd_log_commited_databuf);
 670                 gfs2_assert_withdraw(sdp, 0);
 671         }
 672         gfs2_assert_withdraw(sdp,
 673                         sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
 674
 675         sdp->sd_log_flush_head = sdp->sd_log_head;
 676         sdp->sd_log_flush_wrapped = 0;
 677         ai->ai_first = sdp->sd_log_flush_head;
 678
 679         gfs2_ordered_write(sdp);
 680         lops_before_commit(sdp);
 681
 682         if (sdp->sd_log_head != sdp->sd_log_flush_head) {
 683                 log_write_header(sdp, 0, 0);
 684         } else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
 685                 gfs2_log_lock(sdp);
 686                 atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
 687                 trace_gfs2_log_blocks(sdp, -1);
 688                 gfs2_log_unlock(sdp);
 689                 log_write_header(sdp, 0, PULL);
 690         }
 691         lops_after_commit(sdp, ai);
 692
 693         gfs2_log_lock(sdp);
 694         sdp->sd_log_head = sdp->sd_log_flush_head;
 695         sdp->sd_log_blks_reserved = 0;
 696         sdp->sd_log_commited_buf = 0;
 697         sdp->sd_log_commited_databuf = 0;
 698         sdp->sd_log_commited_revoke = 0;
 699
 700         spin_lock(&sdp->sd_ail_lock);
 701         if (!list_empty(&ai->ai_ail1_list)) {
 702                 list_add(&ai->ai_list, &sdp->sd_ail1_list);
 703                 ai = NULL;
 704         }
 705         spin_unlock(&sdp->sd_ail_lock);
 706         gfs2_log_unlock(sdp);
 707         trace_gfs2_log_flush(sdp, 0);
 708         up_write(&sdp->sd_log_flush_lock);
 709
 710         kfree(ai);
 711 }
 712
 713 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 714 {
 715         unsigned int reserved;
 716         unsigned int unused;
 717
 718         gfs2_log_lock(sdp);
 719
 720         sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
 721         sdp->sd_log_commited_databuf += tr->tr_num_databuf_new -
 722                 tr->tr_num_databuf_rm;
 723         gfs2_assert_withdraw(sdp, (((int)sdp->sd_log_commited_buf) >= 0) ||
 724                              (((int)sdp->sd_log_commited_databuf) >= 0));
 725         sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
 726         reserved = calc_reserved(sdp);
 727         gfs2_assert_withdraw(sdp, sdp->sd_log_blks_reserved + tr->tr_reserved >= reserved);
 728         unused = sdp->sd_log_blks_reserved - reserved + tr->tr_reserved;
 729         atomic_add(unused, &sdp->sd_log_blks_free);
 730         trace_gfs2_log_blocks(sdp, unused);
 731         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 732                              sdp->sd_jdesc->jd_blocks);
 733         sdp->sd_log_blks_reserved = reserved;
 734
 735         gfs2_log_unlock(sdp);
 736 }
 737
 738 static void buf_lo_incore_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 739 {
 740         struct list_head *head = &tr->tr_list_buf;
 741         struct gfs2_bufdata *bd;
 742
 743         gfs2_log_lock(sdp);
 744         while (!list_empty(head)) {
 745                 bd = list_entry(head->next, struct gfs2_bufdata, bd_list_tr);
 746                 list_del_init(&bd->bd_list_tr);
 747                 tr->tr_num_buf--;
 748         }
 749         gfs2_log_unlock(sdp);
 750         gfs2_assert_warn(sdp, !tr->tr_num_buf);
 751 }
 752
 753 /**
 754  * gfs2_log_commit - Commit a transaction to the log
 755  * @sdp: the filesystem
 756  * @tr: the transaction
 757  *
 758  * We wake up gfs2_logd if the number of pinned blocks exceed thresh1
 759  * or the total number of used blocks (pinned blocks plus AIL blocks)
 760  * is greater than thresh2.
 761  *
 762  * At mount time thresh1 is 1/3rd of journal size, thresh2 is 2/3rd of
 763  * journal size.
 764  *
 765  * Returns: errno
 766  */
 767
 768 void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 769 {
 770         log_refund(sdp, tr);
 771         buf_lo_incore_commit(sdp, tr);
 772
 773         up_read(&sdp->sd_log_flush_lock);
 774
 775         if (atomic_read(&sdp->sd_log_pinned) > atomic_read(&sdp->sd_log_thresh1) ||
 776             ((sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free)) >
 777             atomic_read(&sdp->sd_log_thresh2)))
 778                 wake_up(&sdp->sd_logd_waitq);
 779 }
 780
 781 /**
 782  * gfs2_log_shutdown - write a shutdown header into a journal
 783  * @sdp: the filesystem
 784  *
 785  */
 786
 787 void gfs2_log_shutdown(struct gfs2_sbd *sdp)
 788 {
 789         down_write(&sdp->sd_log_flush_lock);
 790
 791         gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
 792         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf);
 793         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
 794         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
 795         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
 796         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
 797
 798         sdp->sd_log_flush_head = sdp->sd_log_head;
 799         sdp->sd_log_flush_wrapped = 0;
 800
 801         log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT,
 802                          (sdp->sd_log_tail == current_tail(sdp)) ? 0 : PULL);
 803
 804         gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks);
 805         gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
 806         gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
 807
 808         sdp->sd_log_head = sdp->sd_log_flush_head;
 809         sdp->sd_log_tail = sdp->sd_log_head;
 810
 811         up_write(&sdp->sd_log_flush_lock);
 812 }
 813
 814
 815 /**
 816  * gfs2_meta_syncfs - sync all the buffers in a filesystem
 817  * @sdp: the filesystem
 818  *
 819  */
 820
 821 void gfs2_meta_syncfs(struct gfs2_sbd *sdp)
 822 {
 823         gfs2_log_flush(sdp, NULL);
 824         for (;;) {
 825                 gfs2_ail1_start(sdp);
 826                 gfs2_ail1_wait(sdp);
 827                 if (gfs2_ail1_empty(sdp))
 828                         break;
 829         }
 830         gfs2_log_flush(sdp, NULL);
 831 }
 832
 833 static inline int gfs2_jrnl_flush_reqd(struct gfs2_sbd *sdp)
 834 {
 835         return (atomic_read(&sdp->sd_log_pinned) >= atomic_read(&sdp->sd_log_thresh1));
 836 }
 837
 838 static inline int gfs2_ail_flush_reqd(struct gfs2_sbd *sdp)
 839 {
 840         unsigned int used_blocks = sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free);
 841         return used_blocks >= atomic_read(&sdp->sd_log_thresh2);
 842 }
 843
 844 /**
 845  * gfs2_logd - Update log tail as Active Items get flushed to in-place blocks
 846  * @sdp: Pointer to GFS2 superblock
 847  *
 848  * Also, periodically check to make sure that we're using the most recent
 849  * journal index.
 850  */
 851
 852 int gfs2_logd(void *data)
 853 {
 854         struct gfs2_sbd *sdp = data;
 855         unsigned long t = 1;
 856         DEFINE_WAIT(wait);
 857         unsigned preflush;
 858
 859         while (!kthread_should_stop()) {
 860
 861                 preflush = atomic_read(&sdp->sd_log_pinned);
 862                 if (gfs2_jrnl_flush_reqd(sdp) || t == 0) {
 863                         gfs2_ail1_empty(sdp);
 864                         gfs2_log_flush(sdp, NULL);
 865                 }
 866
 867                 if (gfs2_ail_flush_reqd(sdp)) {
 868                         gfs2_ail1_start(sdp);
 869                         gfs2_ail1_wait(sdp);
 870                         gfs2_ail1_empty(sdp);
 871                         gfs2_log_flush(sdp, NULL);
 872                 }
 873
 874                 if (!gfs2_ail_flush_reqd(sdp))
 875                         wake_up(&sdp->sd_log_waitq);
 876
 877                 t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
 878
 879                 try_to_freeze();
 880
 881                 do {
 882                         prepare_to_wait(&sdp->sd_logd_waitq, &wait,
 883                                         TASK_INTERRUPTIBLE);
 884                         if (!gfs2_ail_flush_reqd(sdp) &&
 885                             !gfs2_jrnl_flush_reqd(sdp) &&
 886                             !kthread_should_stop())
 887                                 t = schedule_timeout(t);
 888                 } while(t && !gfs2_ail_flush_reqd(sdp) &&
 889                         !gfs2_jrnl_flush_reqd(sdp) &&
 890                         !kthread_should_stop());
 891                 finish_wait(&sdp->sd_logd_waitq, &wait);
 892         }
 893
 894         return 0;
 895 }
 896