fs/gfs2/meta_io.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License v.2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/mm.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/writeback.h>
  18 #include <linux/swap.h>
  19 #include <linux/delay.h>
  20 #include <asm/semaphore.h>
  21
  22 #include "gfs2.h"
  23 #include "glock.h"
  24 #include "glops.h"
  25 #include "inode.h"
  26 #include "log.h"
  27 #include "lops.h"
  28 #include "meta_io.h"
  29 #include "rgrp.h"
  30 #include "trans.h"
  31
  32 #define buffer_busy(bh) \
  33 ((bh)->b_state & ((1ul << BH_Dirty) | (1ul << BH_Lock) | (1ul << BH_Pinned)))
  34 #define buffer_in_io(bh) \
  35 ((bh)->b_state & ((1ul << BH_Dirty) | (1ul << BH_Lock)))
  36
  37 static int aspace_get_block(struct inode *inode, sector_t lblock,
  38                             struct buffer_head *bh_result, int create)
  39 {
  40         gfs2_assert_warn(get_v2sdp(inode->i_sb), 0);
  41         return -EOPNOTSUPP;
  42 }
  43
  44 static int gfs2_aspace_writepage(struct page *page,
  45                                  struct writeback_control *wbc)
  46 {
  47         return block_write_full_page(page, aspace_get_block, wbc);
  48 }
  49
  50 /**
  51  * stuck_releasepage - We're stuck in gfs2_releasepage().  Print stuff out.
  52  * @bh: the buffer we're stuck on
  53  *
  54  */
  55
  56 static void stuck_releasepage(struct buffer_head *bh)
  57 {
  58         struct gfs2_sbd *sdp = get_v2sdp(bh->b_page->mapping->host->i_sb);
  59         struct gfs2_bufdata *bd = get_v2bd(bh);
  60         struct gfs2_glock *gl;
  61
  62         fs_warn(sdp, "stuck in gfs2_releasepage()\n");
  63         fs_warn(sdp, "blkno = %llu, bh->b_count = %d\n",
  64                 (uint64_t)bh->b_blocknr, atomic_read(&bh->b_count));
  65         fs_warn(sdp, "pinned = %u\n", buffer_pinned(bh));
  66         fs_warn(sdp, "get_v2bd(bh) = %s\n", (bd) ? "!NULL" : "NULL");
  67
  68         if (!bd)
  69                 return;
  70
  71         gl = bd->bd_gl;
  72
  73         fs_warn(sdp, "gl = (%u, %llu)\n",
  74                 gl->gl_name.ln_type, gl->gl_name.ln_number);
  75
  76         fs_warn(sdp, "bd_list_tr = %s, bd_le.le_list = %s\n",
  77                 (list_empty(&bd->bd_list_tr)) ? "no" : "yes",
  78                 (list_empty(&bd->bd_le.le_list)) ? "no" : "yes");
  79
  80         if (gl->gl_ops == &gfs2_inode_glops) {
  81                 struct gfs2_inode *ip = get_gl2ip(gl);
  82                 unsigned int x;
  83
  84                 if (!ip)
  85                         return;
  86
  87                 fs_warn(sdp, "ip = %llu %llu\n",
  88                         ip->i_num.no_formal_ino, ip->i_num.no_addr);
  89                 fs_warn(sdp, "ip->i_count = %d, ip->i_vnode = %s\n",
  90                         atomic_read(&ip->i_count),
  91                         (ip->i_vnode) ? "!NULL" : "NULL");
  92
  93                 for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
  94                         fs_warn(sdp, "ip->i_cache[%u] = %s\n",
  95                                 x, (ip->i_cache[x]) ? "!NULL" : "NULL");
  96         }
  97 }
  98
  99 /**
 100  * gfs2_aspace_releasepage - free the metadata associated with a page
 101  * @page: the page that's being released
 102  * @gfp_mask: passed from Linux VFS, ignored by us
 103  *
 104  * Call try_to_free_buffers() if the buffers in this page can be
 105  * released.
 106  *
 107  * Returns: 0
 108  */
 109
 110 static int gfs2_aspace_releasepage(struct page *page, gfp_t gfp_mask)
 111 {
 112         struct inode *aspace = page->mapping->host;
 113         struct gfs2_sbd *sdp = get_v2sdp(aspace->i_sb);
 114         struct buffer_head *bh, *head;
 115         struct gfs2_bufdata *bd;
 116         unsigned long t;
 117
 118         if (!page_has_buffers(page))
 119                 goto out;
 120
 121         head = bh = page_buffers(page);
 122         do {
 123                 t = jiffies;
 124
 125                 while (atomic_read(&bh->b_count)) {
 126                         if (atomic_read(&aspace->i_writecount)) {
 127                                 if (time_after_eq(jiffies, t +
 128                                     gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
 129                                         stuck_releasepage(bh);
 130                                         t = jiffies;
 131                                 }
 132
 133                                 yield();
 134                                 continue;
 135                         }
 136
 137                         return 0;
 138                 }
 139
 140                 gfs2_assert_warn(sdp, !buffer_pinned(bh));
 141
 142                 bd = get_v2bd(bh);
 143                 if (bd) {
 144                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
 145                         gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
 146                         gfs2_assert_warn(sdp, list_empty(&bd->bd_le.le_list));
 147                         gfs2_assert_warn(sdp, !bd->bd_ail);
 148                         kmem_cache_free(gfs2_bufdata_cachep, bd);
 149                         set_v2bd(bh, NULL);
 150                 }
 151
 152                 bh = bh->b_this_page;
 153         }
 154         while (bh != head);
 155
 156  out:
 157         return try_to_free_buffers(page);
 158 }
 159
 160 static struct address_space_operations aspace_aops = {
 161         .writepage = gfs2_aspace_writepage,
 162         .releasepage = gfs2_aspace_releasepage,
 163 };
 164
 165 /**
 166  * gfs2_aspace_get - Create and initialize a struct inode structure
 167  * @sdp: the filesystem the aspace is in
 168  *
 169  * Right now a struct inode is just a struct inode.  Maybe Linux
 170  * will supply a more lightweight address space construct (that works)
 171  * in the future.
 172  *
 173  * Make sure pages/buffers in this aspace aren't in high memory.
 174  *
 175  * Returns: the aspace
 176  */
 177
 178 struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
 179 {
 180         struct inode *aspace;
 181
 182         aspace = new_inode(sdp->sd_vfs);
 183         if (aspace) {
 184                 mapping_set_gfp_mask(aspace->i_mapping, GFP_KERNEL);
 185                 aspace->i_mapping->a_ops = &aspace_aops;
 186                 aspace->i_size = ~0ULL;
 187                 set_v2ip(aspace, NULL);
 188                 insert_inode_hash(aspace);
 189         }
 190
 191         return aspace;
 192 }
 193
 194 void gfs2_aspace_put(struct inode *aspace)
 195 {
 196         remove_inode_hash(aspace);
 197         iput(aspace);
 198 }
 199
 200 /**
 201  * gfs2_ail1_start_one - Start I/O on a part of the AIL
 202  * @sdp: the filesystem
 203  * @tr: the part of the AIL
 204  *
 205  */
 206
 207 void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
 208 {
 209         struct gfs2_bufdata *bd, *s;
 210         struct buffer_head *bh;
 211         int retry;
 212
 213         do {
 214                 retry = 0;
 215
 216                 list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
 217                                                  bd_ail_st_list) {
 218                         bh = bd->bd_bh;
 219
 220                         gfs2_assert(sdp, bd->bd_ail == ai);
 221
 222                         if (!buffer_busy(bh)) {
 223                                 if (!buffer_uptodate(bh))
 224                                         gfs2_io_error_bh(sdp, bh);
 225                                 list_move(&bd->bd_ail_st_list,
 226                                           &ai->ai_ail2_list);
 227                                 continue;
 228                         }
 229
 230                         if (!buffer_dirty(bh))
 231                                 continue;
 232
 233                         list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list);
 234
 235                         gfs2_log_unlock(sdp);
 236                         wait_on_buffer(bh);
 237                         ll_rw_block(WRITE, 1, &bh);
 238                         gfs2_log_lock(sdp);
 239
 240                         retry = 1;
 241                         break;
 242                 }
 243         } while (retry);
 244 }
 245
 246 /**
 247  * gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
 248  * @sdp: the filesystem
 249  * @ai: the AIL entry
 250  *
 251  */
 252
 253 int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai, int flags)
 254 {
 255         struct gfs2_bufdata *bd, *s;
 256         struct buffer_head *bh;
 257
 258         list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
 259                                          bd_ail_st_list) {
 260                 bh = bd->bd_bh;
 261
 262                 gfs2_assert(sdp, bd->bd_ail == ai);
 263
 264                 if (buffer_busy(bh)) {
 265                         if (flags & DIO_ALL)
 266                                 continue;
 267                         else
 268                                 break;
 269                 }
 270
 271                 if (!buffer_uptodate(bh))
 272                         gfs2_io_error_bh(sdp, bh);
 273
 274                 list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
 275         }
 276
 277         return list_empty(&ai->ai_ail1_list);
 278 }
 279
 280 /**
 281  * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced
 282  * @sdp: the filesystem
 283  * @ai: the AIL entry
 284  *
 285  */
 286
 287 void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
 288 {
 289         struct list_head *head = &ai->ai_ail2_list;
 290         struct gfs2_bufdata *bd;
 291
 292         while (!list_empty(head)) {
 293                 bd = list_entry(head->prev, struct gfs2_bufdata,
 294                                 bd_ail_st_list);
 295                 gfs2_assert(sdp, bd->bd_ail == ai);
 296                 bd->bd_ail = NULL;
 297                 list_del(&bd->bd_ail_st_list);
 298                 list_del(&bd->bd_ail_gl_list);
 299                 atomic_dec(&bd->bd_gl->gl_ail_count);
 300                 brelse(bd->bd_bh);
 301         }
 302 }
 303
 304 /**
 305  * ail_empty_gl - remove all buffers for a given lock from the AIL
 306  * @gl: the glock
 307  *
 308  * None of the buffers should be dirty, locked, or pinned.
 309  */
 310
 311 void gfs2_ail_empty_gl(struct gfs2_glock *gl)
 312 {
 313         struct gfs2_sbd *sdp = gl->gl_sbd;
 314         unsigned int blocks;
 315         struct list_head *head = &gl->gl_ail_list;
 316         struct gfs2_bufdata *bd;
 317         struct buffer_head *bh;
 318         uint64_t blkno;
 319         int error;
 320
 321         blocks = atomic_read(&gl->gl_ail_count);
 322         if (!blocks)
 323                 return;
 324
 325         error = gfs2_trans_begin(sdp, 0, blocks);
 326         if (gfs2_assert_withdraw(sdp, !error))
 327                 return;
 328
 329         gfs2_log_lock(sdp);
 330         while (!list_empty(head)) {
 331                 bd = list_entry(head->next, struct gfs2_bufdata,
 332                                 bd_ail_gl_list);
 333                 bh = bd->bd_bh;
 334                 blkno = bh->b_blocknr;
 335                 gfs2_assert_withdraw(sdp, !buffer_busy(bh));
 336
 337                 bd->bd_ail = NULL;
 338                 list_del(&bd->bd_ail_st_list);
 339                 list_del(&bd->bd_ail_gl_list);
 340                 atomic_dec(&gl->gl_ail_count);
 341                 brelse(bh);
 342                 gfs2_log_unlock(sdp);
 343
 344                 gfs2_trans_add_revoke(sdp, blkno);
 345
 346                 gfs2_log_lock(sdp);
 347         }
 348         gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
 349         gfs2_log_unlock(sdp);
 350
 351         gfs2_trans_end(sdp);
 352         gfs2_log_flush(sdp);
 353 }
 354
 355 /**
 356  * gfs2_meta_inval - Invalidate all buffers associated with a glock
 357  * @gl: the glock
 358  *
 359  */
 360
 361 void gfs2_meta_inval(struct gfs2_glock *gl)
 362 {
 363         struct gfs2_sbd *sdp = gl->gl_sbd;
 364         struct inode *aspace = gl->gl_aspace;
 365         struct address_space *mapping = gl->gl_aspace->i_mapping;
 366
 367         gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
 368
 369         atomic_inc(&aspace->i_writecount);
 370         truncate_inode_pages(mapping, 0);
 371         atomic_dec(&aspace->i_writecount);
 372
 373         gfs2_assert_withdraw(sdp, !mapping->nrpages);
 374 }
 375
 376 /**
 377  * gfs2_meta_sync - Sync all buffers associated with a glock
 378  * @gl: The glock
 379  * @flags: DIO_START | DIO_WAIT
 380  *
 381  */
 382
 383 void gfs2_meta_sync(struct gfs2_glock *gl, int flags)
 384 {
 385         struct address_space *mapping = gl->gl_aspace->i_mapping;
 386         int error = 0;
 387
 388         if (flags & DIO_START)
 389                 filemap_fdatawrite(mapping);
 390         if (!error && (flags & DIO_WAIT))
 391                 error = filemap_fdatawait(mapping);
 392
 393         if (error)
 394                 gfs2_io_error(gl->gl_sbd);
 395 }
 396
 397 /**
 398  * getbuf - Get a buffer with a given address space
 399  * @sdp: the filesystem
 400  * @aspace: the address space
 401  * @blkno: the block number (filesystem scope)
 402  * @create: 1 if the buffer should be created
 403  *
 404  * Returns: the buffer
 405  */
 406
 407 static struct buffer_head *getbuf(struct gfs2_sbd *sdp, struct inode *aspace,
 408                                   uint64_t blkno, int create)
 409 {
 410         struct page *page;
 411         struct buffer_head *bh;
 412         unsigned int shift;
 413         unsigned long index;
 414         unsigned int bufnum;
 415
 416         shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
 417         index = blkno >> shift;             /* convert block to page */
 418         bufnum = blkno - (index << shift);  /* block buf index within page */
 419
 420         if (create) {
 421                 for (;;) {
 422                         page = grab_cache_page(aspace->i_mapping, index);
 423                         if (page)
 424                                 break;
 425                         yield();
 426                 }
 427         } else {
 428                 page = find_lock_page(aspace->i_mapping, index);
 429                 if (!page)
 430                         return NULL;
 431         }
 432
 433         if (!page_has_buffers(page))
 434                 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
 435
 436         /* Locate header for our buffer within our page */
 437         for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
 438                 /* Do nothing */;
 439         get_bh(bh);
 440
 441         if (!buffer_mapped(bh))
 442                 map_bh(bh, sdp->sd_vfs, blkno);
 443
 444         unlock_page(page);
 445         mark_page_accessed(page);
 446         page_cache_release(page);
 447
 448         return bh;
 449 }
 450
 451 static void meta_prep_new(struct buffer_head *bh)
 452 {
 453         struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
 454
 455         lock_buffer(bh);
 456         clear_buffer_dirty(bh);
 457         set_buffer_uptodate(bh);
 458         unlock_buffer(bh);
 459
 460         mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
 461 }
 462
 463 /**
 464  * gfs2_meta_new - Get a block
 465  * @gl: The glock associated with this block
 466  * @blkno: The block number
 467  *
 468  * Returns: The buffer
 469  */
 470
 471 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, uint64_t blkno)
 472 {
 473         struct buffer_head *bh;
 474         bh = getbuf(gl->gl_sbd, gl->gl_aspace, blkno, CREATE);
 475         meta_prep_new(bh);
 476         return bh;
 477 }
 478
 479 /**
 480  * gfs2_meta_read - Read a block from disk
 481  * @gl: The glock covering the block
 482  * @blkno: The block number
 483  * @flags: flags to gfs2_dreread()
 484  * @bhp: the place where the buffer is returned (NULL on failure)
 485  *
 486  * Returns: errno
 487  */
 488
 489 int gfs2_meta_read(struct gfs2_glock *gl, uint64_t blkno, int flags,
 490                    struct buffer_head **bhp)
 491 {
 492         int error;
 493
 494         *bhp = getbuf(gl->gl_sbd, gl->gl_aspace, blkno, CREATE);
 495         error = gfs2_meta_reread(gl->gl_sbd, *bhp, flags);
 496         if (error)
 497                 brelse(*bhp);
 498
 499         return error;
 500 }
 501
 502 /**
 503  * gfs2_meta_reread - Reread a block from disk
 504  * @sdp: the filesystem
 505  * @bh: The block to read
 506  * @flags: Flags that control the read
 507  *
 508  * Returns: errno
 509  */
 510
 511 int gfs2_meta_reread(struct gfs2_sbd *sdp, struct buffer_head *bh, int flags)
 512 {
 513         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 514                 return -EIO;
 515
 516         if (flags & DIO_FORCE)
 517                 clear_buffer_uptodate(bh);
 518
 519         if ((flags & DIO_START) && !buffer_uptodate(bh))
 520                 ll_rw_block(READ, 1, &bh);
 521
 522         if (flags & DIO_WAIT) {
 523                 wait_on_buffer(bh);
 524
 525                 if (!buffer_uptodate(bh)) {
 526                         struct gfs2_trans *tr = get_transaction;
 527                         if (tr && tr->tr_touched)
 528                                 gfs2_io_error_bh(sdp, bh);
 529                         return -EIO;
 530                 }
 531                 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 532                         return -EIO;
 533         }
 534
 535         return 0;
 536 }
 537
 538 /**
 539  * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
 540  * @gl: the glock the buffer belongs to
 541  * @bh: The buffer to be attached to
 542  * @meta: Flag to indicate whether its metadata or not
 543  */
 544
 545 void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
 546                          int meta)
 547 {
 548         struct gfs2_bufdata *bd;
 549
 550         if (meta)
 551                 lock_page(bh->b_page);
 552
 553         if (get_v2bd(bh)) {
 554                 if (meta)
 555                         unlock_page(bh->b_page);
 556                 return;
 557         }
 558
 559         bd = kmem_cache_alloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL),
 560         memset(bd, 0, sizeof(struct gfs2_bufdata));
 561
 562         bd->bd_bh = bh;
 563         bd->bd_gl = gl;
 564
 565         INIT_LIST_HEAD(&bd->bd_list_tr);
 566         if (meta) {
 567                 lops_init_le(&bd->bd_le, &gfs2_buf_lops);
 568         } else {
 569                 lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
 570                 get_bh(bh);
 571         }
 572         set_v2bd(bh, bd);
 573
 574         if (meta)
 575                 unlock_page(bh->b_page);
 576 }
 577
 578 /**
 579  * gfs2_pin - Pin a buffer in memory
 580  * @sdp: the filesystem the buffer belongs to
 581  * @bh: The buffer to be pinned
 582  *
 583  */
 584
 585 void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
 586 {
 587         struct gfs2_bufdata *bd = get_v2bd(bh);
 588
 589         gfs2_assert_withdraw(sdp, test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags));
 590
 591         if (test_set_buffer_pinned(bh))
 592                 gfs2_assert_withdraw(sdp, 0);
 593
 594         wait_on_buffer(bh);
 595
 596         /* If this buffer is in the AIL and it has already been written
 597            to in-place disk block, remove it from the AIL. */
 598
 599         gfs2_log_lock(sdp);
 600         if (bd->bd_ail && !buffer_in_io(bh))
 601                 list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
 602         gfs2_log_unlock(sdp);
 603
 604         clear_buffer_dirty(bh);
 605         wait_on_buffer(bh);
 606
 607         if (!buffer_uptodate(bh))
 608                 gfs2_io_error_bh(sdp, bh);
 609
 610         get_bh(bh);
 611 }
 612
 613 /**
 614  * gfs2_unpin - Unpin a buffer
 615  * @sdp: the filesystem the buffer belongs to
 616  * @bh: The buffer to unpin
 617  * @ai:
 618  *
 619  */
 620
 621 void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
 622                 struct gfs2_ail *ai)
 623 {
 624         struct gfs2_bufdata *bd = get_v2bd(bh);
 625
 626         gfs2_assert_withdraw(sdp, buffer_uptodate(bh));
 627
 628         if (!buffer_pinned(bh))
 629                 gfs2_assert_withdraw(sdp, 0);
 630
 631         mark_buffer_dirty(bh);
 632         clear_buffer_pinned(bh);
 633
 634         gfs2_log_lock(sdp);
 635         if (bd->bd_ail) {
 636                 list_del(&bd->bd_ail_st_list);
 637                 brelse(bh);
 638         } else {
 639                 struct gfs2_glock *gl = bd->bd_gl;
 640                 list_add(&bd->bd_ail_gl_list, &gl->gl_ail_list);
 641                 atomic_inc(&gl->gl_ail_count);
 642         }
 643         bd->bd_ail = ai;
 644         list_add(&bd->bd_ail_st_list, &ai->ai_ail1_list);
 645         gfs2_log_unlock(sdp);
 646 }
 647
 648 /**
 649  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 650  * @ip: the inode who owns the buffers
 651  * @bstart: the first buffer in the run
 652  * @blen: the number of buffers in the run
 653  *
 654  */
 655
 656 void gfs2_meta_wipe(struct gfs2_inode *ip, uint64_t bstart, uint32_t blen)
 657 {
 658         struct gfs2_sbd *sdp = ip->i_sbd;
 659         struct inode *aspace = ip->i_gl->gl_aspace;
 660         struct buffer_head *bh;
 661
 662         while (blen) {
 663                 bh = getbuf(sdp, aspace, bstart, NO_CREATE);
 664                 if (bh) {
 665                         struct gfs2_bufdata *bd = get_v2bd(bh);
 666
 667                         if (test_clear_buffer_pinned(bh)) {
 668                                 gfs2_log_lock(sdp);
 669                                 list_del_init(&bd->bd_le.le_list);
 670                                 gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
 671                                 sdp->sd_log_num_buf--;
 672                                 gfs2_log_unlock(sdp);
 673                                 get_transaction->tr_num_buf_rm++;
 674                                 brelse(bh);
 675                         }
 676                         if (bd) {
 677                                 gfs2_log_lock(sdp);
 678                                 if (bd->bd_ail) {
 679                                         uint64_t blkno = bh->b_blocknr;
 680                                         bd->bd_ail = NULL;
 681                                         list_del(&bd->bd_ail_st_list);
 682                                         list_del(&bd->bd_ail_gl_list);
 683                                         atomic_dec(&bd->bd_gl->gl_ail_count);
 684                                         brelse(bh);
 685                                         gfs2_log_unlock(sdp);
 686                                         gfs2_trans_add_revoke(sdp, blkno);
 687                                 } else
 688                                         gfs2_log_unlock(sdp);
 689                         }
 690
 691                         lock_buffer(bh);
 692                         clear_buffer_dirty(bh);
 693                         clear_buffer_uptodate(bh);
 694                         unlock_buffer(bh);
 695
 696                         brelse(bh);
 697                 }
 698
 699                 bstart++;
 700                 blen--;
 701         }
 702 }
 703
 704 /**
 705  * gfs2_meta_cache_flush - get rid of any references on buffers for this inode
 706  * @ip: The GFS2 inode
 707  *
 708  * This releases buffers that are in the most-recently-used array of
 709  * blocks used for indirect block addressing for this inode.
 710  */
 711
 712 void gfs2_meta_cache_flush(struct gfs2_inode *ip)
 713 {
 714         struct buffer_head **bh_slot;
 715         unsigned int x;
 716
 717         spin_lock(&ip->i_spin);
 718
 719         for (x = 0; x < GFS2_MAX_META_HEIGHT; x++) {
 720                 bh_slot = &ip->i_cache[x];
 721                 if (!*bh_slot)
 722                         break;
 723                 brelse(*bh_slot);
 724                 *bh_slot = NULL;
 725         }
 726
 727         spin_unlock(&ip->i_spin);
 728 }
 729
 730 /**
 731  * gfs2_meta_indirect_buffer - Get a metadata buffer
 732  * @ip: The GFS2 inode
 733  * @height: The level of this buf in the metadata (indir addr) tree (if any)
 734  * @num: The block number (device relative) of the buffer
 735  * @new: Non-zero if we may create a new buffer
 736  * @bhp: the buffer is returned here
 737  *
 738  * Try to use the gfs2_inode's MRU metadata tree cache.
 739  *
 740  * Returns: errno
 741  */
 742
 743 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, uint64_t num,
 744                               int new, struct buffer_head **bhp)
 745 {
 746         struct buffer_head *bh, **bh_slot = ip->i_cache + height;
 747         int error;
 748
 749         spin_lock(&ip->i_spin);
 750         bh = *bh_slot;
 751         if (bh) {
 752                 if (bh->b_blocknr == num)
 753                         get_bh(bh);
 754                 else
 755                         bh = NULL;
 756         }
 757         spin_unlock(&ip->i_spin);
 758
 759         if (bh) {
 760                 if (new)
 761                         meta_prep_new(bh);
 762                 else {
 763                         error = gfs2_meta_reread(ip->i_sbd, bh,
 764                                                  DIO_START | DIO_WAIT);
 765                         if (error) {
 766                                 brelse(bh);
 767                                 return error;
 768                         }
 769                 }
 770         } else {
 771                 if (new)
 772                         bh = gfs2_meta_new(ip->i_gl, num);
 773                 else {
 774                         error = gfs2_meta_read(ip->i_gl, num,
 775                                                DIO_START | DIO_WAIT, &bh);
 776                         if (error)
 777                                 return error;
 778                 }
 779
 780                 spin_lock(&ip->i_spin);
 781                 if (*bh_slot != bh) {
 782                         brelse(*bh_slot);
 783                         *bh_slot = bh;
 784                         get_bh(bh);
 785                 }
 786                 spin_unlock(&ip->i_spin);
 787         }
 788
 789         if (new) {
 790                 if (gfs2_assert_warn(ip->i_sbd, height)) {
 791                         brelse(bh);
 792                         return -EIO;
 793                 }
 794                 gfs2_trans_add_bh(ip->i_gl, bh, 1);
 795                 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
 796                 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
 797
 798         } else if (gfs2_metatype_check(ip->i_sbd, bh,
 799                              (height) ? GFS2_METATYPE_IN : GFS2_METATYPE_DI)) {
 800                 brelse(bh);
 801                 return -EIO;
 802         }
 803
 804         *bhp = bh;
 805
 806         return 0;
 807 }
 808
 809 /**
 810  * gfs2_meta_ra - start readahead on an extent of a file
 811  * @gl: the glock the blocks belong to
 812  * @dblock: the starting disk block
 813  * @extlen: the number of blocks in the extent
 814  *
 815  */
 816
 817 void gfs2_meta_ra(struct gfs2_glock *gl, uint64_t dblock, uint32_t extlen)
 818 {
 819         struct gfs2_sbd *sdp = gl->gl_sbd;
 820         struct inode *aspace = gl->gl_aspace;
 821         struct buffer_head *first_bh, *bh;
 822         uint32_t max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 823                           sdp->sd_sb.sb_bsize_shift;
 824         int error;
 825
 826         if (!extlen || !max_ra)
 827                 return;
 828         if (extlen > max_ra)
 829                 extlen = max_ra;
 830
 831         first_bh = getbuf(sdp, aspace, dblock, CREATE);
 832
 833         if (buffer_uptodate(first_bh))
 834                 goto out;
 835         if (!buffer_locked(first_bh)) {
 836                 error = gfs2_meta_reread(sdp, first_bh, DIO_START);
 837                 if (error)
 838                         goto out;
 839         }
 840
 841         dblock++;
 842         extlen--;
 843
 844         while (extlen) {
 845                 bh = getbuf(sdp, aspace, dblock, CREATE);
 846
 847                 if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
 848                         error = gfs2_meta_reread(sdp, bh, DIO_START);
 849                         brelse(bh);
 850                         if (error)
 851                                 goto out;
 852                 } else
 853                         brelse(bh);
 854
 855                 dblock++;
 856                 extlen--;
 857
 858                 if (buffer_uptodate(first_bh))
 859                         break;
 860         }
 861
 862  out:
 863         brelse(first_bh);
 864 }
 865
 866 /**
 867  * gfs2_meta_syncfs - sync all the buffers in a filesystem
 868  * @sdp: the filesystem
 869  *
 870  */
 871
 872 void gfs2_meta_syncfs(struct gfs2_sbd *sdp)
 873 {
 874         gfs2_log_flush(sdp);
 875         for (;;) {
 876                 gfs2_ail1_start(sdp, DIO_ALL);
 877                 if (gfs2_ail1_empty(sdp, DIO_ALL))
 878                         break;
 879                 msleep(100);
 880         }
 881 }
 882