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/blkdev.h>
  22 #include <linux/writeback.h>
  23 #include <linux/list_sort.h>
  24
  25 #include "gfs2.h"
  26 #include "incore.h"
  27 #include "bmap.h"
  28 #include "glock.h"
  29 #include "log.h"
  30 #include "lops.h"
  31 #include "meta_io.h"
  32 #include "util.h"
  33 #include "dir.h"
  34 #include "trace_gfs2.h"
  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_tr = 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_trans *tr)
  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, &tr->tr_ail1_list, bd_ail_st_list) {
 104                 bh = bd->bd_bh;
 105
 106                 gfs2_assert(sdp, bd->bd_tr == tr);
 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, &tr->tr_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, &tr->tr_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_trans *tr;
 149         struct blk_plug plug;
 150
 151         trace_gfs2_ail_flush(sdp, wbc, 1);
 152         blk_start_plug(&plug);
 153         spin_lock(&sdp->sd_ail_lock);
 154 restart:
 155         list_for_each_entry_reverse(tr, head, tr_list) {
 156                 if (wbc->nr_to_write <= 0)
 157                         break;
 158                 if (gfs2_ail1_start_one(sdp, wbc, tr))
 159                         goto restart;
 160         }
 161         spin_unlock(&sdp->sd_ail_lock);
 162         blk_finish_plug(&plug);
 163         trace_gfs2_ail_flush(sdp, wbc, 0);
 164 }
 165
 166 /**
 167  * gfs2_ail1_start - start writeback of all ail1 entries
 168  * @sdp: The superblock
 169  */
 170
 171 static void gfs2_ail1_start(struct gfs2_sbd *sdp)
 172 {
 173         struct writeback_control wbc = {
 174                 .sync_mode = WB_SYNC_NONE,
 175                 .nr_to_write = LONG_MAX,
 176                 .range_start = 0,
 177                 .range_end = LLONG_MAX,
 178         };
 179
 180         return gfs2_ail1_flush(sdp, &wbc);
 181 }
 182
 183 /**
 184  * gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
 185  * @sdp: the filesystem
 186  * @ai: the AIL entry
 187  *
 188  */
 189
 190 static void gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 191 {
 192         struct gfs2_bufdata *bd, *s;
 193         struct buffer_head *bh;
 194
 195         list_for_each_entry_safe_reverse(bd, s, &tr->tr_ail1_list,
 196                                          bd_ail_st_list) {
 197                 bh = bd->bd_bh;
 198                 gfs2_assert(sdp, bd->bd_tr == tr);
 199                 if (buffer_busy(bh))
 200                         continue;
 201                 if (!buffer_uptodate(bh))
 202                         gfs2_io_error_bh(sdp, bh);
 203                 list_move(&bd->bd_ail_st_list, &tr->tr_ail2_list);
 204         }
 205
 206 }
 207
 208 /**
 209  * gfs2_ail1_empty - Try to empty the ail1 lists
 210  * @sdp: The superblock
 211  *
 212  * Tries to empty the ail1 lists, starting with the oldest first
 213  */
 214
 215 static int gfs2_ail1_empty(struct gfs2_sbd *sdp)
 216 {
 217         struct gfs2_trans *tr, *s;
 218         int oldest_tr = 1;
 219         int ret;
 220
 221         spin_lock(&sdp->sd_ail_lock);
 222         list_for_each_entry_safe_reverse(tr, s, &sdp->sd_ail1_list, tr_list) {
 223                 gfs2_ail1_empty_one(sdp, tr);
 224                 if (list_empty(&tr->tr_ail1_list) && oldest_tr)
 225                         list_move(&tr->tr_list, &sdp->sd_ail2_list);
 226                 else
 227                         oldest_tr = 0;
 228         }
 229         ret = list_empty(&sdp->sd_ail1_list);
 230         spin_unlock(&sdp->sd_ail_lock);
 231
 232         return ret;
 233 }
 234
 235 static void gfs2_ail1_wait(struct gfs2_sbd *sdp)
 236 {
 237         struct gfs2_trans *tr;
 238         struct gfs2_bufdata *bd;
 239         struct buffer_head *bh;
 240
 241         spin_lock(&sdp->sd_ail_lock);
 242         list_for_each_entry_reverse(tr, &sdp->sd_ail1_list, tr_list) {
 243                 list_for_each_entry(bd, &tr->tr_ail1_list, bd_ail_st_list) {
 244                         bh = bd->bd_bh;
 245                         if (!buffer_locked(bh))
 246                                 continue;
 247                         get_bh(bh);
 248                         spin_unlock(&sdp->sd_ail_lock);
 249                         wait_on_buffer(bh);
 250                         brelse(bh);
 251                         return;
 252                 }
 253         }
 254         spin_unlock(&sdp->sd_ail_lock);
 255 }
 256
 257 /**
 258  * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced
 259  * @sdp: the filesystem
 260  * @ai: the AIL entry
 261  *
 262  */
 263
 264 static void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 265 {
 266         struct list_head *head = &tr->tr_ail2_list;
 267         struct gfs2_bufdata *bd;
 268
 269         while (!list_empty(head)) {
 270                 bd = list_entry(head->prev, struct gfs2_bufdata,
 271                                 bd_ail_st_list);
 272                 gfs2_assert(sdp, bd->bd_tr == tr);
 273                 gfs2_remove_from_ail(bd);
 274         }
 275 }
 276
 277 static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
 278 {
 279         struct gfs2_trans *tr, *safe;
 280         unsigned int old_tail = sdp->sd_log_tail;
 281         int wrap = (new_tail < old_tail);
 282         int a, b, rm;
 283
 284         spin_lock(&sdp->sd_ail_lock);
 285
 286         list_for_each_entry_safe(tr, safe, &sdp->sd_ail2_list, tr_list) {
 287                 a = (old_tail <= tr->tr_first);
 288                 b = (tr->tr_first < new_tail);
 289                 rm = (wrap) ? (a || b) : (a && b);
 290                 if (!rm)
 291                         continue;
 292
 293                 gfs2_ail2_empty_one(sdp, tr);
 294                 list_del(&tr->tr_list);
 295                 gfs2_assert_warn(sdp, list_empty(&tr->tr_ail1_list));
 296                 gfs2_assert_warn(sdp, list_empty(&tr->tr_ail2_list));
 297                 kfree(tr);
 298         }
 299
 300         spin_unlock(&sdp->sd_ail_lock);
 301 }
 302
 303 /**
 304  * gfs2_log_reserve - Make a log reservation
 305  * @sdp: The GFS2 superblock
 306  * @blks: The number of blocks to reserve
 307  *
 308  * Note that we never give out the last few blocks of the journal. Thats
 309  * due to the fact that there is a small number of header blocks
 310  * associated with each log flush. The exact number can't be known until
 311  * flush time, so we ensure that we have just enough free blocks at all
 312  * times to avoid running out during a log flush.
 313  *
 314  * We no longer flush the log here, instead we wake up logd to do that
 315  * for us. To avoid the thundering herd and to ensure that we deal fairly
 316  * with queued waiters, we use an exclusive wait. This means that when we
 317  * get woken with enough journal space to get our reservation, we need to
 318  * wake the next waiter on the list.
 319  *
 320  * Returns: errno
 321  */
 322
 323 int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 324 {
 325         unsigned reserved_blks = 7 * (4096 / sdp->sd_vfs->s_blocksize);
 326         unsigned wanted = blks + reserved_blks;
 327         DEFINE_WAIT(wait);
 328         int did_wait = 0;
 329         unsigned int free_blocks;
 330
 331         if (gfs2_assert_warn(sdp, blks) ||
 332             gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
 333                 return -EINVAL;
 334 retry:
 335         free_blocks = atomic_read(&sdp->sd_log_blks_free);
 336         if (unlikely(free_blocks <= wanted)) {
 337                 do {
 338                         prepare_to_wait_exclusive(&sdp->sd_log_waitq, &wait,
 339                                         TASK_UNINTERRUPTIBLE);
 340                         wake_up(&sdp->sd_logd_waitq);
 341                         did_wait = 1;
 342                         if (atomic_read(&sdp->sd_log_blks_free) <= wanted)
 343                                 io_schedule();
 344                         free_blocks = atomic_read(&sdp->sd_log_blks_free);
 345                 } while(free_blocks <= wanted);
 346                 finish_wait(&sdp->sd_log_waitq, &wait);
 347         }
 348         if (atomic_cmpxchg(&sdp->sd_log_blks_free, free_blocks,
 349                                 free_blocks - blks) != free_blocks)
 350                 goto retry;
 351         trace_gfs2_log_blocks(sdp, -blks);
 352
 353         /*
 354          * If we waited, then so might others, wake them up _after_ we get
 355          * our share of the log.
 356          */
 357         if (unlikely(did_wait))
 358                 wake_up(&sdp->sd_log_waitq);
 359
 360         down_read(&sdp->sd_log_flush_lock);
 361
 362         return 0;
 363 }
 364
 365 /**
 366  * log_distance - Compute distance between two journal blocks
 367  * @sdp: The GFS2 superblock
 368  * @newer: The most recent journal block of the pair
 369  * @older: The older journal block of the pair
 370  *
 371  *   Compute the distance (in the journal direction) between two
 372  *   blocks in the journal
 373  *
 374  * Returns: the distance in blocks
 375  */
 376
 377 static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer,
 378                                         unsigned int older)
 379 {
 380         int dist;
 381
 382         dist = newer - older;
 383         if (dist < 0)
 384                 dist += sdp->sd_jdesc->jd_blocks;
 385
 386         return dist;
 387 }
 388
 389 /**
 390  * calc_reserved - Calculate the number of blocks to reserve when
 391  *                 refunding a transaction's unused buffers.
 392  * @sdp: The GFS2 superblock
 393  *
 394  * This is complex.  We need to reserve room for all our currently used
 395  * metadata buffers (e.g. normal file I/O rewriting file time stamps) and
 396  * all our journaled data buffers for journaled files (e.g. files in the
 397  * meta_fs like rindex, or files for which chattr +j was done.)
 398  * If we don't reserve enough space, gfs2_log_refund and gfs2_log_flush
 399  * will count it as free space (sd_log_blks_free) and corruption will follow.
 400  *
 401  * We can have metadata bufs and jdata bufs in the same journal.  So each
 402  * type gets its own log header, for which we need to reserve a block.
 403  * In fact, each type has the potential for needing more than one header
 404  * in cases where we have more buffers than will fit on a journal page.
 405  * Metadata journal entries take up half the space of journaled buffer entries.
 406  * Thus, metadata entries have buf_limit (502) and journaled buffers have
 407  * databuf_limit (251) before they cause a wrap around.
 408  *
 409  * Also, we need to reserve blocks for revoke journal entries and one for an
 410  * overall header for the lot.
 411  *
 412  * Returns: the number of blocks reserved
 413  */
 414 static unsigned int calc_reserved(struct gfs2_sbd *sdp)
 415 {
 416         unsigned int reserved = 0;
 417         unsigned int mbuf;
 418         unsigned int dbuf;
 419         struct gfs2_trans *tr = sdp->sd_log_tr;
 420
 421         if (tr) {
 422                 mbuf = tr->tr_num_buf_new - tr->tr_num_buf_rm;
 423                 dbuf = tr->tr_num_databuf_new - tr->tr_num_databuf_rm;
 424                 reserved = mbuf + dbuf;
 425                 /* Account for header blocks */
 426                 reserved += DIV_ROUND_UP(mbuf, buf_limit(sdp));
 427                 reserved += DIV_ROUND_UP(dbuf, databuf_limit(sdp));
 428         }
 429
 430         if (sdp->sd_log_commited_revoke > 0)
 431                 reserved += gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
 432                                           sizeof(u64));
 433         /* One for the overall header */
 434         if (reserved)
 435                 reserved++;
 436         return reserved;
 437 }
 438
 439 static unsigned int current_tail(struct gfs2_sbd *sdp)
 440 {
 441         struct gfs2_trans *tr;
 442         unsigned int tail;
 443
 444         spin_lock(&sdp->sd_ail_lock);
 445
 446         if (list_empty(&sdp->sd_ail1_list)) {
 447                 tail = sdp->sd_log_head;
 448         } else {
 449                 tr = list_entry(sdp->sd_ail1_list.prev, struct gfs2_trans,
 450                                 tr_list);
 451                 tail = tr->tr_first;
 452         }
 453
 454         spin_unlock(&sdp->sd_ail_lock);
 455
 456         return tail;
 457 }
 458
 459 static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
 460 {
 461         unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
 462
 463         ail2_empty(sdp, new_tail);
 464
 465         atomic_add(dist, &sdp->sd_log_blks_free);
 466         trace_gfs2_log_blocks(sdp, dist);
 467         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 468                              sdp->sd_jdesc->jd_blocks);
 469
 470         sdp->sd_log_tail = new_tail;
 471 }
 472
 473
 474 static void log_flush_wait(struct gfs2_sbd *sdp)
 475 {
 476         DEFINE_WAIT(wait);
 477
 478         if (atomic_read(&sdp->sd_log_in_flight)) {
 479                 do {
 480                         prepare_to_wait(&sdp->sd_log_flush_wait, &wait,
 481                                         TASK_UNINTERRUPTIBLE);
 482                         if (atomic_read(&sdp->sd_log_in_flight))
 483                                 io_schedule();
 484                 } while(atomic_read(&sdp->sd_log_in_flight));
 485                 finish_wait(&sdp->sd_log_flush_wait, &wait);
 486         }
 487 }
 488
 489 static int ip_cmp(void *priv, struct list_head *a, struct list_head *b)
 490 {
 491         struct gfs2_inode *ipa, *ipb;
 492
 493         ipa = list_entry(a, struct gfs2_inode, i_ordered);
 494         ipb = list_entry(b, struct gfs2_inode, i_ordered);
 495
 496         if (ipa->i_no_addr < ipb->i_no_addr)
 497                 return -1;
 498         if (ipa->i_no_addr > ipb->i_no_addr)
 499                 return 1;
 500         return 0;
 501 }
 502
 503 static void gfs2_ordered_write(struct gfs2_sbd *sdp)
 504 {
 505         struct gfs2_inode *ip;
 506         LIST_HEAD(written);
 507
 508         spin_lock(&sdp->sd_ordered_lock);
 509         list_sort(NULL, &sdp->sd_log_le_ordered, &ip_cmp);
 510         while (!list_empty(&sdp->sd_log_le_ordered)) {
 511                 ip = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_inode, i_ordered);
 512                 list_move(&ip->i_ordered, &written);
 513                 if (ip->i_inode.i_mapping->nrpages == 0)
 514                         continue;
 515                 spin_unlock(&sdp->sd_ordered_lock);
 516                 filemap_fdatawrite(ip->i_inode.i_mapping);
 517                 spin_lock(&sdp->sd_ordered_lock);
 518         }
 519         list_splice(&written, &sdp->sd_log_le_ordered);
 520         spin_unlock(&sdp->sd_ordered_lock);
 521 }
 522
 523 static void gfs2_ordered_wait(struct gfs2_sbd *sdp)
 524 {
 525         struct gfs2_inode *ip;
 526
 527         spin_lock(&sdp->sd_ordered_lock);
 528         while (!list_empty(&sdp->sd_log_le_ordered)) {
 529                 ip = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_inode, i_ordered);
 530                 list_del(&ip->i_ordered);
 531                 WARN_ON(!test_and_clear_bit(GIF_ORDERED, &ip->i_flags));
 532                 if (ip->i_inode.i_mapping->nrpages == 0)
 533                         continue;
 534                 spin_unlock(&sdp->sd_ordered_lock);
 535                 filemap_fdatawait(ip->i_inode.i_mapping);
 536                 spin_lock(&sdp->sd_ordered_lock);
 537         }
 538         spin_unlock(&sdp->sd_ordered_lock);
 539 }
 540
 541 void gfs2_ordered_del_inode(struct gfs2_inode *ip)
 542 {
 543         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 544
 545         spin_lock(&sdp->sd_ordered_lock);
 546         if (test_and_clear_bit(GIF_ORDERED, &ip->i_flags))
 547                 list_del(&ip->i_ordered);
 548         spin_unlock(&sdp->sd_ordered_lock);
 549 }
 550
 551 void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 552 {
 553         struct buffer_head *bh = bd->bd_bh;
 554         struct gfs2_glock *gl = bd->bd_gl;
 555
 556         bh->b_private = NULL;
 557         bd->bd_blkno = bh->b_blocknr;
 558         gfs2_remove_from_ail(bd); /* drops ref on bh */
 559         bd->bd_bh = NULL;
 560         bd->bd_ops = &gfs2_revoke_lops;
 561         sdp->sd_log_num_revoke++;
 562         atomic_inc(&gl->gl_revokes);
 563         set_bit(GLF_LFLUSH, &gl->gl_flags);
 564         list_add(&bd->bd_list, &sdp->sd_log_le_revoke);
 565 }
 566
 567 void gfs2_write_revokes(struct gfs2_sbd *sdp)
 568 {
 569         struct gfs2_trans *tr;
 570         struct gfs2_bufdata *bd, *tmp;
 571         int have_revokes = 0;
 572         int max_revokes = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) / sizeof(u64);
 573
 574         gfs2_ail1_empty(sdp);
 575         spin_lock(&sdp->sd_ail_lock);
 576         list_for_each_entry(tr, &sdp->sd_ail1_list, tr_list) {
 577                 list_for_each_entry(bd, &tr->tr_ail2_list, bd_ail_st_list) {
 578                         if (list_empty(&bd->bd_list)) {
 579                                 have_revokes = 1;
 580                                 goto done;
 581                         }
 582                 }
 583         }
 584 done:
 585         spin_unlock(&sdp->sd_ail_lock);
 586         if (have_revokes == 0)
 587                 return;
 588         while (sdp->sd_log_num_revoke > max_revokes)
 589                 max_revokes += (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header)) / sizeof(u64);
 590         max_revokes -= sdp->sd_log_num_revoke;
 591         if (!sdp->sd_log_num_revoke) {
 592                 atomic_dec(&sdp->sd_log_blks_free);
 593                 /* If no blocks have been reserved, we need to also
 594                  * reserve a block for the header */
 595                 if (!sdp->sd_log_blks_reserved)
 596                         atomic_dec(&sdp->sd_log_blks_free);
 597         }
 598         gfs2_log_lock(sdp);
 599         spin_lock(&sdp->sd_ail_lock);
 600         list_for_each_entry(tr, &sdp->sd_ail1_list, tr_list) {
 601                 list_for_each_entry_safe(bd, tmp, &tr->tr_ail2_list, bd_ail_st_list) {
 602                         if (max_revokes == 0)
 603                                 goto out_of_blocks;
 604                         if (!list_empty(&bd->bd_list))
 605                                 continue;
 606                         gfs2_add_revoke(sdp, bd);
 607                         max_revokes--;
 608                 }
 609         }
 610 out_of_blocks:
 611         spin_unlock(&sdp->sd_ail_lock);
 612         gfs2_log_unlock(sdp);
 613
 614         if (!sdp->sd_log_num_revoke) {
 615                 atomic_inc(&sdp->sd_log_blks_free);
 616                 if (!sdp->sd_log_blks_reserved)
 617                         atomic_inc(&sdp->sd_log_blks_free);
 618         }
 619 }
 620
 621 /**
 622  * log_write_header - Get and initialize a journal header buffer
 623  * @sdp: The GFS2 superblock
 624  *
 625  * Returns: the initialized log buffer descriptor
 626  */
 627
 628 static void log_write_header(struct gfs2_sbd *sdp, u32 flags)
 629 {
 630         struct gfs2_log_header *lh;
 631         unsigned int tail;
 632         u32 hash;
 633         int rw = WRITE_FLUSH_FUA | REQ_META;
 634         struct page *page = mempool_alloc(gfs2_page_pool, GFP_NOIO);
 635         lh = page_address(page);
 636         clear_page(lh);
 637
 638         tail = current_tail(sdp);
 639
 640         lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
 641         lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
 642         lh->lh_header.__pad0 = cpu_to_be64(0);
 643         lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
 644         lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
 645         lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++);
 646         lh->lh_flags = cpu_to_be32(flags);
 647         lh->lh_tail = cpu_to_be32(tail);
 648         lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head);
 649         hash = gfs2_disk_hash(page_address(page), sizeof(struct gfs2_log_header));
 650         lh->lh_hash = cpu_to_be32(hash);
 651
 652         if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) {
 653                 gfs2_ordered_wait(sdp);
 654                 log_flush_wait(sdp);
 655                 rw = WRITE_SYNC | REQ_META | REQ_PRIO;
 656         }
 657
 658         sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
 659         gfs2_log_write_page(sdp, page);
 660         gfs2_log_flush_bio(sdp, rw);
 661         log_flush_wait(sdp);
 662
 663         if (sdp->sd_log_tail != tail)
 664                 log_pull_tail(sdp, tail);
 665 }
 666
 667 /**
 668  * gfs2_log_flush - flush incore transaction(s)
 669  * @sdp: the filesystem
 670  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
 671  *
 672  */
 673
 674 void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 675 {
 676         struct gfs2_trans *tr;
 677
 678         down_write(&sdp->sd_log_flush_lock);
 679
 680         /* Log might have been flushed while we waited for the flush lock */
 681         if (gl && !test_bit(GLF_LFLUSH, &gl->gl_flags)) {
 682                 up_write(&sdp->sd_log_flush_lock);
 683                 return;
 684         }
 685         trace_gfs2_log_flush(sdp, 1);
 686
 687         sdp->sd_log_flush_head = sdp->sd_log_head;
 688         sdp->sd_log_flush_wrapped = 0;
 689         tr = sdp->sd_log_tr;
 690         if (tr) {
 691                 sdp->sd_log_tr = NULL;
 692                 INIT_LIST_HEAD(&tr->tr_ail1_list);
 693                 INIT_LIST_HEAD(&tr->tr_ail2_list);
 694                 tr->tr_first = sdp->sd_log_flush_head;
 695         }
 696
 697         gfs2_assert_withdraw(sdp,
 698                         sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
 699
 700         gfs2_ordered_write(sdp);
 701         lops_before_commit(sdp, tr);
 702         gfs2_log_flush_bio(sdp, WRITE);
 703
 704         if (sdp->sd_log_head != sdp->sd_log_flush_head) {
 705                 log_flush_wait(sdp);
 706                 log_write_header(sdp, 0);
 707         } else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
 708                 atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
 709                 trace_gfs2_log_blocks(sdp, -1);
 710                 log_write_header(sdp, 0);
 711         }
 712         lops_after_commit(sdp, tr);
 713
 714         gfs2_log_lock(sdp);
 715         sdp->sd_log_head = sdp->sd_log_flush_head;
 716         sdp->sd_log_blks_reserved = 0;
 717         sdp->sd_log_commited_revoke = 0;
 718
 719         spin_lock(&sdp->sd_ail_lock);
 720         if (tr && !list_empty(&tr->tr_ail1_list)) {
 721                 list_add(&tr->tr_list, &sdp->sd_ail1_list);
 722                 tr = NULL;
 723         }
 724         spin_unlock(&sdp->sd_ail_lock);
 725         gfs2_log_unlock(sdp);
 726         trace_gfs2_log_flush(sdp, 0);
 727         up_write(&sdp->sd_log_flush_lock);
 728
 729         kfree(tr);
 730 }
 731
 732 /**
 733  * gfs2_merge_trans - Merge a new transaction into a cached transaction
 734  * @old: Original transaction to be expanded
 735  * @new: New transaction to be merged
 736  */
 737
 738 static void gfs2_merge_trans(struct gfs2_trans *old, struct gfs2_trans *new)
 739 {
 740         WARN_ON_ONCE(old->tr_attached != 1);
 741
 742         old->tr_num_buf_new     += new->tr_num_buf_new;
 743         old->tr_num_databuf_new += new->tr_num_databuf_new;
 744         old->tr_num_buf_rm      += new->tr_num_buf_rm;
 745         old->tr_num_databuf_rm  += new->tr_num_databuf_rm;
 746         old->tr_num_revoke      += new->tr_num_revoke;
 747         old->tr_num_revoke_rm   += new->tr_num_revoke_rm;
 748
 749         list_splice_tail_init(&new->tr_databuf, &old->tr_databuf);
 750         list_splice_tail_init(&new->tr_buf, &old->tr_buf);
 751 }
 752
 753 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 754 {
 755         unsigned int reserved;
 756         unsigned int unused;
 757         unsigned int maxres;
 758
 759         gfs2_log_lock(sdp);
 760
 761         if (sdp->sd_log_tr) {
 762                 gfs2_merge_trans(sdp->sd_log_tr, tr);
 763         } else if (tr->tr_num_buf_new || tr->tr_num_databuf_new) {
 764                 gfs2_assert_withdraw(sdp, tr->tr_t_gh.gh_gl);
 765                 sdp->sd_log_tr = tr;
 766                 tr->tr_attached = 1;
 767         }
 768
 769         sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
 770         reserved = calc_reserved(sdp);
 771         maxres = sdp->sd_log_blks_reserved + tr->tr_reserved;
 772         gfs2_assert_withdraw(sdp, maxres >= reserved);
 773         unused = maxres - reserved;
 774         atomic_add(unused, &sdp->sd_log_blks_free);
 775         trace_gfs2_log_blocks(sdp, unused);
 776         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 777                              sdp->sd_jdesc->jd_blocks);
 778         sdp->sd_log_blks_reserved = reserved;
 779
 780         gfs2_log_unlock(sdp);
 781 }
 782
 783 /**
 784  * gfs2_log_commit - Commit a transaction to the log
 785  * @sdp: the filesystem
 786  * @tr: the transaction
 787  *
 788  * We wake up gfs2_logd if the number of pinned blocks exceed thresh1
 789  * or the total number of used blocks (pinned blocks plus AIL blocks)
 790  * is greater than thresh2.
 791  *
 792  * At mount time thresh1 is 1/3rd of journal size, thresh2 is 2/3rd of
 793  * journal size.
 794  *
 795  * Returns: errno
 796  */
 797
 798 void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 799 {
 800         log_refund(sdp, tr);
 801
 802         if (atomic_read(&sdp->sd_log_pinned) > atomic_read(&sdp->sd_log_thresh1) ||
 803             ((sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free)) >
 804             atomic_read(&sdp->sd_log_thresh2)))
 805                 wake_up(&sdp->sd_logd_waitq);
 806 }
 807
 808 /**
 809  * gfs2_log_shutdown - write a shutdown header into a journal
 810  * @sdp: the filesystem
 811  *
 812  */
 813
 814 void gfs2_log_shutdown(struct gfs2_sbd *sdp)
 815 {
 816         down_write(&sdp->sd_log_flush_lock);
 817
 818         gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
 819         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
 820         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
 821
 822         sdp->sd_log_flush_head = sdp->sd_log_head;
 823         sdp->sd_log_flush_wrapped = 0;
 824
 825         log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT);
 826
 827         gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks);
 828         gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
 829         gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
 830
 831         sdp->sd_log_head = sdp->sd_log_flush_head;
 832         sdp->sd_log_tail = sdp->sd_log_head;
 833
 834         up_write(&sdp->sd_log_flush_lock);
 835 }
 836
 837
 838 /**
 839  * gfs2_meta_syncfs - sync all the buffers in a filesystem
 840  * @sdp: the filesystem
 841  *
 842  */
 843
 844 void gfs2_meta_syncfs(struct gfs2_sbd *sdp)
 845 {
 846         gfs2_log_flush(sdp, NULL);
 847         for (;;) {
 848                 gfs2_ail1_start(sdp);
 849                 gfs2_ail1_wait(sdp);
 850                 if (gfs2_ail1_empty(sdp))
 851                         break;
 852         }
 853         gfs2_log_flush(sdp, NULL);
 854 }
 855
 856 static inline int gfs2_jrnl_flush_reqd(struct gfs2_sbd *sdp)
 857 {
 858         return (atomic_read(&sdp->sd_log_pinned) >= atomic_read(&sdp->sd_log_thresh1));
 859 }
 860
 861 static inline int gfs2_ail_flush_reqd(struct gfs2_sbd *sdp)
 862 {
 863         unsigned int used_blocks = sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free);
 864         return used_blocks >= atomic_read(&sdp->sd_log_thresh2);
 865 }
 866
 867 /**
 868  * gfs2_logd - Update log tail as Active Items get flushed to in-place blocks
 869  * @sdp: Pointer to GFS2 superblock
 870  *
 871  * Also, periodically check to make sure that we're using the most recent
 872  * journal index.
 873  */
 874
 875 int gfs2_logd(void *data)
 876 {
 877         struct gfs2_sbd *sdp = data;
 878         unsigned long t = 1;
 879         DEFINE_WAIT(wait);
 880
 881         while (!kthread_should_stop()) {
 882
 883                 if (gfs2_jrnl_flush_reqd(sdp) || t == 0) {
 884                         gfs2_ail1_empty(sdp);
 885                         gfs2_log_flush(sdp, NULL);
 886                 }
 887
 888                 if (gfs2_ail_flush_reqd(sdp)) {
 889                         gfs2_ail1_start(sdp);
 890                         gfs2_ail1_wait(sdp);
 891                         gfs2_ail1_empty(sdp);
 892                         gfs2_log_flush(sdp, NULL);
 893                 }
 894
 895                 if (!gfs2_ail_flush_reqd(sdp))
 896                         wake_up(&sdp->sd_log_waitq);
 897
 898                 t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
 899
 900                 try_to_freeze();
 901
 902                 do {
 903                         prepare_to_wait(&sdp->sd_logd_waitq, &wait,
 904                                         TASK_INTERRUPTIBLE);
 905                         if (!gfs2_ail_flush_reqd(sdp) &&
 906                             !gfs2_jrnl_flush_reqd(sdp) &&
 907                             !kthread_should_stop())
 908                                 t = schedule_timeout(t);
 909                 } while(t && !gfs2_ail_flush_reqd(sdp) &&
 910                         !gfs2_jrnl_flush_reqd(sdp) &&
 911                         !kthread_should_stop());
 912                 finish_wait(&sdp->sd_logd_waitq, &wait);
 913         }
 914
 915         return 0;
 916 }
 917