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_release - Release a given number of log blocks
 305  * @sdp: The GFS2 superblock
 306  * @blks: The number of blocks
 307  *
 308  */
 309
 310 void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
 311 {
 312
 313         atomic_add(blks, &sdp->sd_log_blks_free);
 314         trace_gfs2_log_blocks(sdp, blks);
 315         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 316                                   sdp->sd_jdesc->jd_blocks);
 317         up_read(&sdp->sd_log_flush_lock);
 318 }
 319
 320 /**
 321  * gfs2_log_reserve - Make a log reservation
 322  * @sdp: The GFS2 superblock
 323  * @blks: The number of blocks to reserve
 324  *
 325  * Note that we never give out the last few blocks of the journal. Thats
 326  * due to the fact that there is a small number of header blocks
 327  * associated with each log flush. The exact number can't be known until
 328  * flush time, so we ensure that we have just enough free blocks at all
 329  * times to avoid running out during a log flush.
 330  *
 331  * We no longer flush the log here, instead we wake up logd to do that
 332  * for us. To avoid the thundering herd and to ensure that we deal fairly
 333  * with queued waiters, we use an exclusive wait. This means that when we
 334  * get woken with enough journal space to get our reservation, we need to
 335  * wake the next waiter on the list.
 336  *
 337  * Returns: errno
 338  */
 339
 340 int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 341 {
 342         int ret = 0;
 343         unsigned reserved_blks = 7 * (4096 / sdp->sd_vfs->s_blocksize);
 344         unsigned wanted = blks + reserved_blks;
 345         DEFINE_WAIT(wait);
 346         int did_wait = 0;
 347         unsigned int free_blocks;
 348
 349         if (gfs2_assert_warn(sdp, blks) ||
 350             gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
 351                 return -EINVAL;
 352 retry:
 353         free_blocks = atomic_read(&sdp->sd_log_blks_free);
 354         if (unlikely(free_blocks <= wanted)) {
 355                 do {
 356                         prepare_to_wait_exclusive(&sdp->sd_log_waitq, &wait,
 357                                         TASK_UNINTERRUPTIBLE);
 358                         wake_up(&sdp->sd_logd_waitq);
 359                         did_wait = 1;
 360                         if (atomic_read(&sdp->sd_log_blks_free) <= wanted)
 361                                 io_schedule();
 362                         free_blocks = atomic_read(&sdp->sd_log_blks_free);
 363                 } while(free_blocks <= wanted);
 364                 finish_wait(&sdp->sd_log_waitq, &wait);
 365         }
 366         atomic_inc(&sdp->sd_reserving_log);
 367         if (atomic_cmpxchg(&sdp->sd_log_blks_free, free_blocks,
 368                                 free_blocks - blks) != free_blocks) {
 369                 if (atomic_dec_and_test(&sdp->sd_reserving_log))
 370                         wake_up(&sdp->sd_reserving_log_wait);
 371                 goto retry;
 372         }
 373         trace_gfs2_log_blocks(sdp, -blks);
 374
 375         /*
 376          * If we waited, then so might others, wake them up _after_ we get
 377          * our share of the log.
 378          */
 379         if (unlikely(did_wait))
 380                 wake_up(&sdp->sd_log_waitq);
 381
 382         down_read(&sdp->sd_log_flush_lock);
 383         if (unlikely(!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))) {
 384                 gfs2_log_release(sdp, blks);
 385                 ret = -EROFS;
 386         }
 387         if (atomic_dec_and_test(&sdp->sd_reserving_log))
 388                 wake_up(&sdp->sd_reserving_log_wait);
 389         return ret;
 390 }
 391
 392 /**
 393  * log_distance - Compute distance between two journal blocks
 394  * @sdp: The GFS2 superblock
 395  * @newer: The most recent journal block of the pair
 396  * @older: The older journal block of the pair
 397  *
 398  *   Compute the distance (in the journal direction) between two
 399  *   blocks in the journal
 400  *
 401  * Returns: the distance in blocks
 402  */
 403
 404 static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer,
 405                                         unsigned int older)
 406 {
 407         int dist;
 408
 409         dist = newer - older;
 410         if (dist < 0)
 411                 dist += sdp->sd_jdesc->jd_blocks;
 412
 413         return dist;
 414 }
 415
 416 /**
 417  * calc_reserved - Calculate the number of blocks to reserve when
 418  *                 refunding a transaction's unused buffers.
 419  * @sdp: The GFS2 superblock
 420  *
 421  * This is complex.  We need to reserve room for all our currently used
 422  * metadata buffers (e.g. normal file I/O rewriting file time stamps) and
 423  * all our journaled data buffers for journaled files (e.g. files in the
 424  * meta_fs like rindex, or files for which chattr +j was done.)
 425  * If we don't reserve enough space, gfs2_log_refund and gfs2_log_flush
 426  * will count it as free space (sd_log_blks_free) and corruption will follow.
 427  *
 428  * We can have metadata bufs and jdata bufs in the same journal.  So each
 429  * type gets its own log header, for which we need to reserve a block.
 430  * In fact, each type has the potential for needing more than one header
 431  * in cases where we have more buffers than will fit on a journal page.
 432  * Metadata journal entries take up half the space of journaled buffer entries.
 433  * Thus, metadata entries have buf_limit (502) and journaled buffers have
 434  * databuf_limit (251) before they cause a wrap around.
 435  *
 436  * Also, we need to reserve blocks for revoke journal entries and one for an
 437  * overall header for the lot.
 438  *
 439  * Returns: the number of blocks reserved
 440  */
 441 static unsigned int calc_reserved(struct gfs2_sbd *sdp)
 442 {
 443         unsigned int reserved = 0;
 444         unsigned int mbuf;
 445         unsigned int dbuf;
 446         struct gfs2_trans *tr = sdp->sd_log_tr;
 447
 448         if (tr) {
 449                 mbuf = tr->tr_num_buf_new - tr->tr_num_buf_rm;
 450                 dbuf = tr->tr_num_databuf_new - tr->tr_num_databuf_rm;
 451                 reserved = mbuf + dbuf;
 452                 /* Account for header blocks */
 453                 reserved += DIV_ROUND_UP(mbuf, buf_limit(sdp));
 454                 reserved += DIV_ROUND_UP(dbuf, databuf_limit(sdp));
 455         }
 456
 457         if (sdp->sd_log_commited_revoke > 0)
 458                 reserved += gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
 459                                           sizeof(u64));
 460         /* One for the overall header */
 461         if (reserved)
 462                 reserved++;
 463         return reserved;
 464 }
 465
 466 static unsigned int current_tail(struct gfs2_sbd *sdp)
 467 {
 468         struct gfs2_trans *tr;
 469         unsigned int tail;
 470
 471         spin_lock(&sdp->sd_ail_lock);
 472
 473         if (list_empty(&sdp->sd_ail1_list)) {
 474                 tail = sdp->sd_log_head;
 475         } else {
 476                 tr = list_entry(sdp->sd_ail1_list.prev, struct gfs2_trans,
 477                                 tr_list);
 478                 tail = tr->tr_first;
 479         }
 480
 481         spin_unlock(&sdp->sd_ail_lock);
 482
 483         return tail;
 484 }
 485
 486 static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
 487 {
 488         unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
 489
 490         ail2_empty(sdp, new_tail);
 491
 492         atomic_add(dist, &sdp->sd_log_blks_free);
 493         trace_gfs2_log_blocks(sdp, dist);
 494         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 495                              sdp->sd_jdesc->jd_blocks);
 496
 497         sdp->sd_log_tail = new_tail;
 498 }
 499
 500
 501 static void log_flush_wait(struct gfs2_sbd *sdp)
 502 {
 503         DEFINE_WAIT(wait);
 504
 505         if (atomic_read(&sdp->sd_log_in_flight)) {
 506                 do {
 507                         prepare_to_wait(&sdp->sd_log_flush_wait, &wait,
 508                                         TASK_UNINTERRUPTIBLE);
 509                         if (atomic_read(&sdp->sd_log_in_flight))
 510                                 io_schedule();
 511                 } while(atomic_read(&sdp->sd_log_in_flight));
 512                 finish_wait(&sdp->sd_log_flush_wait, &wait);
 513         }
 514 }
 515
 516 static int ip_cmp(void *priv, struct list_head *a, struct list_head *b)
 517 {
 518         struct gfs2_inode *ipa, *ipb;
 519
 520         ipa = list_entry(a, struct gfs2_inode, i_ordered);
 521         ipb = list_entry(b, struct gfs2_inode, i_ordered);
 522
 523         if (ipa->i_no_addr < ipb->i_no_addr)
 524                 return -1;
 525         if (ipa->i_no_addr > ipb->i_no_addr)
 526                 return 1;
 527         return 0;
 528 }
 529
 530 static void gfs2_ordered_write(struct gfs2_sbd *sdp)
 531 {
 532         struct gfs2_inode *ip;
 533         LIST_HEAD(written);
 534
 535         spin_lock(&sdp->sd_ordered_lock);
 536         list_sort(NULL, &sdp->sd_log_le_ordered, &ip_cmp);
 537         while (!list_empty(&sdp->sd_log_le_ordered)) {
 538                 ip = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_inode, i_ordered);
 539                 list_move(&ip->i_ordered, &written);
 540                 if (ip->i_inode.i_mapping->nrpages == 0)
 541                         continue;
 542                 spin_unlock(&sdp->sd_ordered_lock);
 543                 filemap_fdatawrite(ip->i_inode.i_mapping);
 544                 spin_lock(&sdp->sd_ordered_lock);
 545         }
 546         list_splice(&written, &sdp->sd_log_le_ordered);
 547         spin_unlock(&sdp->sd_ordered_lock);
 548 }
 549
 550 static void gfs2_ordered_wait(struct gfs2_sbd *sdp)
 551 {
 552         struct gfs2_inode *ip;
 553
 554         spin_lock(&sdp->sd_ordered_lock);
 555         while (!list_empty(&sdp->sd_log_le_ordered)) {
 556                 ip = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_inode, i_ordered);
 557                 list_del(&ip->i_ordered);
 558                 WARN_ON(!test_and_clear_bit(GIF_ORDERED, &ip->i_flags));
 559                 if (ip->i_inode.i_mapping->nrpages == 0)
 560                         continue;
 561                 spin_unlock(&sdp->sd_ordered_lock);
 562                 filemap_fdatawait(ip->i_inode.i_mapping);
 563                 spin_lock(&sdp->sd_ordered_lock);
 564         }
 565         spin_unlock(&sdp->sd_ordered_lock);
 566 }
 567
 568 void gfs2_ordered_del_inode(struct gfs2_inode *ip)
 569 {
 570         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 571
 572         spin_lock(&sdp->sd_ordered_lock);
 573         if (test_and_clear_bit(GIF_ORDERED, &ip->i_flags))
 574                 list_del(&ip->i_ordered);
 575         spin_unlock(&sdp->sd_ordered_lock);
 576 }
 577
 578 void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 579 {
 580         struct buffer_head *bh = bd->bd_bh;
 581         struct gfs2_glock *gl = bd->bd_gl;
 582
 583         bh->b_private = NULL;
 584         bd->bd_blkno = bh->b_blocknr;
 585         gfs2_remove_from_ail(bd); /* drops ref on bh */
 586         bd->bd_bh = NULL;
 587         bd->bd_ops = &gfs2_revoke_lops;
 588         sdp->sd_log_num_revoke++;
 589         atomic_inc(&gl->gl_revokes);
 590         set_bit(GLF_LFLUSH, &gl->gl_flags);
 591         list_add(&bd->bd_list, &sdp->sd_log_le_revoke);
 592 }
 593
 594 void gfs2_write_revokes(struct gfs2_sbd *sdp)
 595 {
 596         struct gfs2_trans *tr;
 597         struct gfs2_bufdata *bd, *tmp;
 598         int have_revokes = 0;
 599         int max_revokes = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) / sizeof(u64);
 600
 601         gfs2_ail1_empty(sdp);
 602         spin_lock(&sdp->sd_ail_lock);
 603         list_for_each_entry(tr, &sdp->sd_ail1_list, tr_list) {
 604                 list_for_each_entry(bd, &tr->tr_ail2_list, bd_ail_st_list) {
 605                         if (list_empty(&bd->bd_list)) {
 606                                 have_revokes = 1;
 607                                 goto done;
 608                         }
 609                 }
 610         }
 611 done:
 612         spin_unlock(&sdp->sd_ail_lock);
 613         if (have_revokes == 0)
 614                 return;
 615         while (sdp->sd_log_num_revoke > max_revokes)
 616                 max_revokes += (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header)) / sizeof(u64);
 617         max_revokes -= sdp->sd_log_num_revoke;
 618         if (!sdp->sd_log_num_revoke) {
 619                 atomic_dec(&sdp->sd_log_blks_free);
 620                 /* If no blocks have been reserved, we need to also
 621                  * reserve a block for the header */
 622                 if (!sdp->sd_log_blks_reserved)
 623                         atomic_dec(&sdp->sd_log_blks_free);
 624         }
 625         gfs2_log_lock(sdp);
 626         spin_lock(&sdp->sd_ail_lock);
 627         list_for_each_entry(tr, &sdp->sd_ail1_list, tr_list) {
 628                 list_for_each_entry_safe(bd, tmp, &tr->tr_ail2_list, bd_ail_st_list) {
 629                         if (max_revokes == 0)
 630                                 goto out_of_blocks;
 631                         if (!list_empty(&bd->bd_list))
 632                                 continue;
 633                         gfs2_add_revoke(sdp, bd);
 634                         max_revokes--;
 635                 }
 636         }
 637 out_of_blocks:
 638         spin_unlock(&sdp->sd_ail_lock);
 639         gfs2_log_unlock(sdp);
 640
 641         if (!sdp->sd_log_num_revoke) {
 642                 atomic_inc(&sdp->sd_log_blks_free);
 643                 if (!sdp->sd_log_blks_reserved)
 644                         atomic_inc(&sdp->sd_log_blks_free);
 645         }
 646 }
 647
 648 /**
 649  * log_write_header - Get and initialize a journal header buffer
 650  * @sdp: The GFS2 superblock
 651  *
 652  * Returns: the initialized log buffer descriptor
 653  */
 654
 655 static void log_write_header(struct gfs2_sbd *sdp, u32 flags)
 656 {
 657         struct gfs2_log_header *lh;
 658         unsigned int tail;
 659         u32 hash;
 660         int op_flags = REQ_PREFLUSH | REQ_FUA | REQ_META;
 661         struct page *page = mempool_alloc(gfs2_page_pool, GFP_NOIO);
 662         enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
 663         lh = page_address(page);
 664         clear_page(lh);
 665
 666         gfs2_assert_withdraw(sdp, (state != SFS_FROZEN));
 667
 668         tail = current_tail(sdp);
 669
 670         lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
 671         lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
 672         lh->lh_header.__pad0 = cpu_to_be64(0);
 673         lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
 674         lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
 675         lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++);
 676         lh->lh_flags = cpu_to_be32(flags);
 677         lh->lh_tail = cpu_to_be32(tail);
 678         lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head);
 679         hash = gfs2_disk_hash(page_address(page), sizeof(struct gfs2_log_header));
 680         lh->lh_hash = cpu_to_be32(hash);
 681
 682         if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) {
 683                 gfs2_ordered_wait(sdp);
 684                 log_flush_wait(sdp);
 685                 op_flags = REQ_SYNC | REQ_META | REQ_PRIO;
 686         }
 687
 688         sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
 689         gfs2_log_write_page(sdp, page);
 690         gfs2_log_flush_bio(sdp, REQ_OP_WRITE, op_flags);
 691         log_flush_wait(sdp);
 692
 693         if (sdp->sd_log_tail != tail)
 694                 log_pull_tail(sdp, tail);
 695 }
 696
 697 /**
 698  * gfs2_log_flush - flush incore transaction(s)
 699  * @sdp: the filesystem
 700  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
 701  *
 702  */
 703
 704 void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl,
 705                     enum gfs2_flush_type type)
 706 {
 707         struct gfs2_trans *tr;
 708         enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
 709
 710         down_write(&sdp->sd_log_flush_lock);
 711
 712         /* Log might have been flushed while we waited for the flush lock */
 713         if (gl && !test_bit(GLF_LFLUSH, &gl->gl_flags)) {
 714                 up_write(&sdp->sd_log_flush_lock);
 715                 return;
 716         }
 717         trace_gfs2_log_flush(sdp, 1);
 718
 719         if (type == SHUTDOWN_FLUSH)
 720                 clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
 721
 722         sdp->sd_log_flush_head = sdp->sd_log_head;
 723         sdp->sd_log_flush_wrapped = 0;
 724         tr = sdp->sd_log_tr;
 725         if (tr) {
 726                 sdp->sd_log_tr = NULL;
 727                 INIT_LIST_HEAD(&tr->tr_ail1_list);
 728                 INIT_LIST_HEAD(&tr->tr_ail2_list);
 729                 tr->tr_first = sdp->sd_log_flush_head;
 730                 if (unlikely (state == SFS_FROZEN))
 731                         gfs2_assert_withdraw(sdp, !tr->tr_num_buf_new && !tr->tr_num_databuf_new);
 732         }
 733
 734         if (unlikely(state == SFS_FROZEN))
 735                 gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
 736         gfs2_assert_withdraw(sdp,
 737                         sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
 738
 739         gfs2_ordered_write(sdp);
 740         lops_before_commit(sdp, tr);
 741         gfs2_log_flush_bio(sdp, REQ_OP_WRITE, 0);
 742
 743         if (sdp->sd_log_head != sdp->sd_log_flush_head) {
 744                 log_flush_wait(sdp);
 745                 log_write_header(sdp, 0);
 746         } else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
 747                 atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
 748                 trace_gfs2_log_blocks(sdp, -1);
 749                 log_write_header(sdp, 0);
 750         }
 751         lops_after_commit(sdp, tr);
 752
 753         gfs2_log_lock(sdp);
 754         sdp->sd_log_head = sdp->sd_log_flush_head;
 755         sdp->sd_log_blks_reserved = 0;
 756         sdp->sd_log_commited_revoke = 0;
 757
 758         spin_lock(&sdp->sd_ail_lock);
 759         if (tr && !list_empty(&tr->tr_ail1_list)) {
 760                 list_add(&tr->tr_list, &sdp->sd_ail1_list);
 761                 tr = NULL;
 762         }
 763         spin_unlock(&sdp->sd_ail_lock);
 764         gfs2_log_unlock(sdp);
 765
 766         if (type != NORMAL_FLUSH) {
 767                 if (!sdp->sd_log_idle) {
 768                         for (;;) {
 769                                 gfs2_ail1_start(sdp);
 770                                 gfs2_ail1_wait(sdp);
 771                                 if (gfs2_ail1_empty(sdp))
 772                                         break;
 773                         }
 774                         atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
 775                         trace_gfs2_log_blocks(sdp, -1);
 776                         sdp->sd_log_flush_wrapped = 0;
 777                         log_write_header(sdp, 0);
 778                         sdp->sd_log_head = sdp->sd_log_flush_head;
 779                 }
 780                 if (type == SHUTDOWN_FLUSH || type == FREEZE_FLUSH)
 781                         gfs2_log_shutdown(sdp);
 782                 if (type == FREEZE_FLUSH)
 783                         atomic_set(&sdp->sd_freeze_state, SFS_FROZEN);
 784         }
 785
 786         trace_gfs2_log_flush(sdp, 0);
 787         up_write(&sdp->sd_log_flush_lock);
 788
 789         kfree(tr);
 790 }
 791
 792 /**
 793  * gfs2_merge_trans - Merge a new transaction into a cached transaction
 794  * @old: Original transaction to be expanded
 795  * @new: New transaction to be merged
 796  */
 797
 798 static void gfs2_merge_trans(struct gfs2_trans *old, struct gfs2_trans *new)
 799 {
 800         WARN_ON_ONCE(old->tr_attached != 1);
 801
 802         old->tr_num_buf_new     += new->tr_num_buf_new;
 803         old->tr_num_databuf_new += new->tr_num_databuf_new;
 804         old->tr_num_buf_rm      += new->tr_num_buf_rm;
 805         old->tr_num_databuf_rm  += new->tr_num_databuf_rm;
 806         old->tr_num_revoke      += new->tr_num_revoke;
 807         old->tr_num_revoke_rm   += new->tr_num_revoke_rm;
 808
 809         list_splice_tail_init(&new->tr_databuf, &old->tr_databuf);
 810         list_splice_tail_init(&new->tr_buf, &old->tr_buf);
 811 }
 812
 813 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 814 {
 815         unsigned int reserved;
 816         unsigned int unused;
 817         unsigned int maxres;
 818
 819         gfs2_log_lock(sdp);
 820
 821         if (sdp->sd_log_tr) {
 822                 gfs2_merge_trans(sdp->sd_log_tr, tr);
 823         } else if (tr->tr_num_buf_new || tr->tr_num_databuf_new) {
 824                 gfs2_assert_withdraw(sdp, tr->tr_alloced);
 825                 sdp->sd_log_tr = tr;
 826                 tr->tr_attached = 1;
 827         }
 828
 829         sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
 830         reserved = calc_reserved(sdp);
 831         maxres = sdp->sd_log_blks_reserved + tr->tr_reserved;
 832         gfs2_assert_withdraw(sdp, maxres >= reserved);
 833         unused = maxres - reserved;
 834         atomic_add(unused, &sdp->sd_log_blks_free);
 835         trace_gfs2_log_blocks(sdp, unused);
 836         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 837                              sdp->sd_jdesc->jd_blocks);
 838         sdp->sd_log_blks_reserved = reserved;
 839
 840         gfs2_log_unlock(sdp);
 841 }
 842
 843 /**
 844  * gfs2_log_commit - Commit a transaction to the log
 845  * @sdp: the filesystem
 846  * @tr: the transaction
 847  *
 848  * We wake up gfs2_logd if the number of pinned blocks exceed thresh1
 849  * or the total number of used blocks (pinned blocks plus AIL blocks)
 850  * is greater than thresh2.
 851  *
 852  * At mount time thresh1 is 1/3rd of journal size, thresh2 is 2/3rd of
 853  * journal size.
 854  *
 855  * Returns: errno
 856  */
 857
 858 void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 859 {
 860         log_refund(sdp, tr);
 861
 862         if (atomic_read(&sdp->sd_log_pinned) > atomic_read(&sdp->sd_log_thresh1) ||
 863             ((sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free)) >
 864             atomic_read(&sdp->sd_log_thresh2)))
 865                 wake_up(&sdp->sd_logd_waitq);
 866 }
 867
 868 /**
 869  * gfs2_log_shutdown - write a shutdown header into a journal
 870  * @sdp: the filesystem
 871  *
 872  */
 873
 874 void gfs2_log_shutdown(struct gfs2_sbd *sdp)
 875 {
 876         gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
 877         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
 878         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
 879
 880         sdp->sd_log_flush_head = sdp->sd_log_head;
 881         sdp->sd_log_flush_wrapped = 0;
 882
 883         log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT);
 884
 885         gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
 886         gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
 887
 888         sdp->sd_log_head = sdp->sd_log_flush_head;
 889         sdp->sd_log_tail = sdp->sd_log_head;
 890 }
 891
 892 static inline int gfs2_jrnl_flush_reqd(struct gfs2_sbd *sdp)
 893 {
 894         return (atomic_read(&sdp->sd_log_pinned) >= atomic_read(&sdp->sd_log_thresh1));
 895 }
 896
 897 static inline int gfs2_ail_flush_reqd(struct gfs2_sbd *sdp)
 898 {
 899         unsigned int used_blocks = sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free);
 900         return used_blocks >= atomic_read(&sdp->sd_log_thresh2);
 901 }
 902
 903 /**
 904  * gfs2_logd - Update log tail as Active Items get flushed to in-place blocks
 905  * @sdp: Pointer to GFS2 superblock
 906  *
 907  * Also, periodically check to make sure that we're using the most recent
 908  * journal index.
 909  */
 910
 911 int gfs2_logd(void *data)
 912 {
 913         struct gfs2_sbd *sdp = data;
 914         unsigned long t = 1;
 915         DEFINE_WAIT(wait);
 916
 917         while (!kthread_should_stop()) {
 918
 919                 if (gfs2_jrnl_flush_reqd(sdp) || t == 0) {
 920                         gfs2_ail1_empty(sdp);
 921                         gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
 922                 }
 923
 924                 if (gfs2_ail_flush_reqd(sdp)) {
 925                         gfs2_ail1_start(sdp);
 926                         gfs2_ail1_wait(sdp);
 927                         gfs2_ail1_empty(sdp);
 928                         gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
 929                 }
 930
 931                 if (!gfs2_ail_flush_reqd(sdp))
 932                         wake_up(&sdp->sd_log_waitq);
 933
 934                 t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
 935
 936                 try_to_freeze();
 937
 938                 do {
 939                         prepare_to_wait(&sdp->sd_logd_waitq, &wait,
 940                                         TASK_INTERRUPTIBLE);
 941                         if (!gfs2_ail_flush_reqd(sdp) &&
 942                             !gfs2_jrnl_flush_reqd(sdp) &&
 943                             !kthread_should_stop())
 944                                 t = schedule_timeout(t);
 945                 } while(t && !gfs2_ail_flush_reqd(sdp) &&
 946                         !gfs2_jrnl_flush_reqd(sdp) &&
 947                         !kthread_should_stop());
 948                 finish_wait(&sdp->sd_logd_waitq, &wait);
 949         }
 950
 951         return 0;
 952 }
 953