fs/gfs2/meta_io.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 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/mm.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/writeback.h>
  18 #include <linux/swap.h>
  19 #include <linux/delay.h>
  20 #include <linux/gfs2_ondisk.h>
  21
  22 #include "gfs2.h"
  23 #include "lm_interface.h"
  24 #include "incore.h"
  25 #include "glock.h"
  26 #include "glops.h"
  27 #include "inode.h"
  28 #include "log.h"
  29 #include "lops.h"
  30 #include "meta_io.h"
  31 #include "rgrp.h"
  32 #include "trans.h"
  33 #include "util.h"
  34 #include "ops_address.h"
  35
  36 #define buffer_busy(bh) \
  37 ((bh)->b_state & ((1ul << BH_Dirty) | (1ul << BH_Lock) | (1ul << BH_Pinned)))
  38 #define buffer_in_io(bh) \
  39 ((bh)->b_state & ((1ul << BH_Dirty) | (1ul << BH_Lock)))
  40
  41 static int aspace_get_block(struct inode *inode, sector_t lblock,
  42                             struct buffer_head *bh_result, int create)
  43 {
  44         gfs2_assert_warn(inode->i_sb->s_fs_info, 0);
  45         return -EOPNOTSUPP;
  46 }
  47
  48 static int gfs2_aspace_writepage(struct page *page,
  49                                  struct writeback_control *wbc)
  50 {
  51         return block_write_full_page(page, aspace_get_block, wbc);
  52 }
  53
  54 static const struct address_space_operations aspace_aops = {
  55         .writepage = gfs2_aspace_writepage,
  56         .releasepage = gfs2_releasepage,
  57 };
  58
  59 /**
  60  * gfs2_aspace_get - Create and initialize a struct inode structure
  61  * @sdp: the filesystem the aspace is in
  62  *
  63  * Right now a struct inode is just a struct inode.  Maybe Linux
  64  * will supply a more lightweight address space construct (that works)
  65  * in the future.
  66  *
  67  * Make sure pages/buffers in this aspace aren't in high memory.
  68  *
  69  * Returns: the aspace
  70  */
  71
  72 struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
  73 {
  74         struct inode *aspace;
  75
  76         aspace = new_inode(sdp->sd_vfs);
  77         if (aspace) {
  78                 mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
  79                 aspace->i_mapping->a_ops = &aspace_aops;
  80                 aspace->i_size = ~0ULL;
  81                 aspace->u.generic_ip = NULL;
  82                 insert_inode_hash(aspace);
  83         }
  84         return aspace;
  85 }
  86
  87 void gfs2_aspace_put(struct inode *aspace)
  88 {
  89         remove_inode_hash(aspace);
  90         iput(aspace);
  91 }
  92
  93 /**
  94  * gfs2_ail1_start_one - Start I/O on a part of the AIL
  95  * @sdp: the filesystem
  96  * @tr: the part of the AIL
  97  *
  98  */
  99
 100 void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
 101 {
 102         struct gfs2_bufdata *bd, *s;
 103         struct buffer_head *bh;
 104         int retry;
 105
 106         BUG_ON(!spin_is_locked(&sdp->sd_log_lock));
 107
 108         do {
 109                 retry = 0;
 110
 111                 list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
 112                                                  bd_ail_st_list) {
 113                         bh = bd->bd_bh;
 114
 115                         gfs2_assert(sdp, bd->bd_ail == ai);
 116
 117                         if (!buffer_busy(bh)) {
 118                                 if (!buffer_uptodate(bh)) {
 119                                         gfs2_log_unlock(sdp);
 120                                         gfs2_io_error_bh(sdp, bh);
 121                                         gfs2_log_lock(sdp);
 122                                 }
 123                                 list_move(&bd->bd_ail_st_list,
 124                                           &ai->ai_ail2_list);
 125                                 continue;
 126                         }
 127
 128                         if (!buffer_dirty(bh))
 129                                 continue;
 130
 131                         list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list);
 132
 133                         gfs2_log_unlock(sdp);
 134                         wait_on_buffer(bh);
 135                         ll_rw_block(WRITE, 1, &bh);
 136                         gfs2_log_lock(sdp);
 137
 138                         retry = 1;
 139                         break;
 140                 }
 141         } while (retry);
 142 }
 143
 144 /**
 145  * gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
 146  * @sdp: the filesystem
 147  * @ai: the AIL entry
 148  *
 149  */
 150
 151 int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai, int flags)
 152 {
 153         struct gfs2_bufdata *bd, *s;
 154         struct buffer_head *bh;
 155
 156         list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
 157                                          bd_ail_st_list) {
 158                 bh = bd->bd_bh;
 159
 160                 gfs2_assert(sdp, bd->bd_ail == ai);
 161
 162                 if (buffer_busy(bh)) {
 163                         if (flags & DIO_ALL)
 164                                 continue;
 165                         else
 166                                 break;
 167                 }
 168
 169                 if (!buffer_uptodate(bh))
 170                         gfs2_io_error_bh(sdp, bh);
 171
 172                 list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
 173         }
 174
 175         return list_empty(&ai->ai_ail1_list);
 176 }
 177
 178 /**
 179  * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced
 180  * @sdp: the filesystem
 181  * @ai: the AIL entry
 182  *
 183  */
 184
 185 void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
 186 {
 187         struct list_head *head = &ai->ai_ail2_list;
 188         struct gfs2_bufdata *bd;
 189
 190         while (!list_empty(head)) {
 191                 bd = list_entry(head->prev, struct gfs2_bufdata,
 192                                 bd_ail_st_list);
 193                 gfs2_assert(sdp, bd->bd_ail == ai);
 194                 bd->bd_ail = NULL;
 195                 list_del(&bd->bd_ail_st_list);
 196                 list_del(&bd->bd_ail_gl_list);
 197                 atomic_dec(&bd->bd_gl->gl_ail_count);
 198                 brelse(bd->bd_bh);
 199         }
 200 }
 201
 202 /**
 203  * ail_empty_gl - remove all buffers for a given lock from the AIL
 204  * @gl: the glock
 205  *
 206  * None of the buffers should be dirty, locked, or pinned.
 207  */
 208
 209 void gfs2_ail_empty_gl(struct gfs2_glock *gl)
 210 {
 211         struct gfs2_sbd *sdp = gl->gl_sbd;
 212         unsigned int blocks;
 213         struct list_head *head = &gl->gl_ail_list;
 214         struct gfs2_bufdata *bd;
 215         struct buffer_head *bh;
 216         u64 blkno;
 217         int error;
 218
 219         blocks = atomic_read(&gl->gl_ail_count);
 220         if (!blocks)
 221                 return;
 222
 223         error = gfs2_trans_begin(sdp, 0, blocks);
 224         if (gfs2_assert_withdraw(sdp, !error))
 225                 return;
 226
 227         gfs2_log_lock(sdp);
 228         while (!list_empty(head)) {
 229                 bd = list_entry(head->next, struct gfs2_bufdata,
 230                                 bd_ail_gl_list);
 231                 bh = bd->bd_bh;
 232                 blkno = bh->b_blocknr;
 233                 gfs2_assert_withdraw(sdp, !buffer_busy(bh));
 234
 235                 bd->bd_ail = NULL;
 236                 list_del(&bd->bd_ail_st_list);
 237                 list_del(&bd->bd_ail_gl_list);
 238                 atomic_dec(&gl->gl_ail_count);
 239                 brelse(bh);
 240                 gfs2_log_unlock(sdp);
 241
 242                 gfs2_trans_add_revoke(sdp, blkno);
 243
 244                 gfs2_log_lock(sdp);
 245         }
 246         gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
 247         gfs2_log_unlock(sdp);
 248
 249         gfs2_trans_end(sdp);
 250         gfs2_log_flush(sdp, NULL);
 251 }
 252
 253 /**
 254  * gfs2_meta_inval - Invalidate all buffers associated with a glock
 255  * @gl: the glock
 256  *
 257  */
 258
 259 void gfs2_meta_inval(struct gfs2_glock *gl)
 260 {
 261         struct gfs2_sbd *sdp = gl->gl_sbd;
 262         struct inode *aspace = gl->gl_aspace;
 263         struct address_space *mapping = gl->gl_aspace->i_mapping;
 264
 265         gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
 266
 267         atomic_inc(&aspace->i_writecount);
 268         truncate_inode_pages(mapping, 0);
 269         atomic_dec(&aspace->i_writecount);
 270
 271         gfs2_assert_withdraw(sdp, !mapping->nrpages);
 272 }
 273
 274 /**
 275  * gfs2_meta_sync - Sync all buffers associated with a glock
 276  * @gl: The glock
 277  * @flags: DIO_START | DIO_WAIT
 278  *
 279  */
 280
 281 void gfs2_meta_sync(struct gfs2_glock *gl, int flags)
 282 {
 283         struct address_space *mapping = gl->gl_aspace->i_mapping;
 284         int error = 0;
 285
 286         if (flags & DIO_START)
 287                 filemap_fdatawrite(mapping);
 288         if (!error && (flags & DIO_WAIT))
 289                 error = filemap_fdatawait(mapping);
 290
 291         if (error)
 292                 gfs2_io_error(gl->gl_sbd);
 293 }
 294
 295 /**
 296  * getbuf - Get a buffer with a given address space
 297  * @sdp: the filesystem
 298  * @aspace: the address space
 299  * @blkno: the block number (filesystem scope)
 300  * @create: 1 if the buffer should be created
 301  *
 302  * Returns: the buffer
 303  */
 304
 305 static struct buffer_head *getbuf(struct gfs2_sbd *sdp, struct inode *aspace,
 306                                   u64 blkno, int create)
 307 {
 308         struct page *page;
 309         struct buffer_head *bh;
 310         unsigned int shift;
 311         unsigned long index;
 312         unsigned int bufnum;
 313
 314         shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
 315         index = blkno >> shift;             /* convert block to page */
 316         bufnum = blkno - (index << shift);  /* block buf index within page */
 317
 318         if (create) {
 319                 for (;;) {
 320                         page = grab_cache_page(aspace->i_mapping, index);
 321                         if (page)
 322                                 break;
 323                         yield();
 324                 }
 325         } else {
 326                 page = find_lock_page(aspace->i_mapping, index);
 327                 if (!page)
 328                         return NULL;
 329         }
 330
 331         if (!page_has_buffers(page))
 332                 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
 333
 334         /* Locate header for our buffer within our page */
 335         for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
 336                 /* Do nothing */;
 337         get_bh(bh);
 338
 339         if (!buffer_mapped(bh))
 340                 map_bh(bh, sdp->sd_vfs, blkno);
 341
 342         unlock_page(page);
 343         mark_page_accessed(page);
 344         page_cache_release(page);
 345
 346         return bh;
 347 }
 348
 349 static void meta_prep_new(struct buffer_head *bh)
 350 {
 351         struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
 352
 353         lock_buffer(bh);
 354         clear_buffer_dirty(bh);
 355         set_buffer_uptodate(bh);
 356         unlock_buffer(bh);
 357
 358         mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
 359 }
 360
 361 /**
 362  * gfs2_meta_new - Get a block
 363  * @gl: The glock associated with this block
 364  * @blkno: The block number
 365  *
 366  * Returns: The buffer
 367  */
 368
 369 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
 370 {
 371         struct buffer_head *bh;
 372         bh = getbuf(gl->gl_sbd, gl->gl_aspace, blkno, CREATE);
 373         meta_prep_new(bh);
 374         return bh;
 375 }
 376
 377 /**
 378  * gfs2_meta_read - Read a block from disk
 379  * @gl: The glock covering the block
 380  * @blkno: The block number
 381  * @flags: flags to gfs2_dreread()
 382  * @bhp: the place where the buffer is returned (NULL on failure)
 383  *
 384  * Returns: errno
 385  */
 386
 387 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
 388                    struct buffer_head **bhp)
 389 {
 390         int error;
 391
 392         *bhp = getbuf(gl->gl_sbd, gl->gl_aspace, blkno, CREATE);
 393         error = gfs2_meta_reread(gl->gl_sbd, *bhp, flags);
 394         if (error)
 395                 brelse(*bhp);
 396
 397         return error;
 398 }
 399
 400 /**
 401  * gfs2_meta_reread - Reread a block from disk
 402  * @sdp: the filesystem
 403  * @bh: The block to read
 404  * @flags: Flags that control the read
 405  *
 406  * Returns: errno
 407  */
 408
 409 int gfs2_meta_reread(struct gfs2_sbd *sdp, struct buffer_head *bh, int flags)
 410 {
 411         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 412                 return -EIO;
 413
 414         if (flags & DIO_FORCE)
 415                 clear_buffer_uptodate(bh);
 416
 417         if ((flags & DIO_START) && !buffer_uptodate(bh))
 418                 ll_rw_block(READ, 1, &bh);
 419
 420         if (flags & DIO_WAIT) {
 421                 wait_on_buffer(bh);
 422
 423                 if (!buffer_uptodate(bh)) {
 424                         struct gfs2_trans *tr = current->journal_info;
 425                         if (tr && tr->tr_touched)
 426                                 gfs2_io_error_bh(sdp, bh);
 427                         return -EIO;
 428                 }
 429                 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 430                         return -EIO;
 431         }
 432
 433         return 0;
 434 }
 435
 436 /**
 437  * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
 438  * @gl: the glock the buffer belongs to
 439  * @bh: The buffer to be attached to
 440  * @meta: Flag to indicate whether its metadata or not
 441  */
 442
 443 void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
 444                          int meta)
 445 {
 446         struct gfs2_bufdata *bd;
 447
 448         if (meta)
 449                 lock_page(bh->b_page);
 450
 451         if (bh->b_private) {
 452                 if (meta)
 453                         unlock_page(bh->b_page);
 454                 return;
 455         }
 456
 457         bd = kmem_cache_alloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL),
 458         memset(bd, 0, sizeof(struct gfs2_bufdata));
 459         bd->bd_bh = bh;
 460         bd->bd_gl = gl;
 461
 462         INIT_LIST_HEAD(&bd->bd_list_tr);
 463         if (meta) {
 464                 lops_init_le(&bd->bd_le, &gfs2_buf_lops);
 465         } else {
 466                 lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
 467         }
 468         bh->b_private = bd;
 469
 470         if (meta)
 471                 unlock_page(bh->b_page);
 472 }
 473
 474 /**
 475  * gfs2_pin - Pin a buffer in memory
 476  * @sdp: the filesystem the buffer belongs to
 477  * @bh: The buffer to be pinned
 478  *
 479  */
 480
 481 void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
 482 {
 483         struct gfs2_bufdata *bd = bh->b_private;
 484
 485         gfs2_assert_withdraw(sdp, test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags));
 486
 487         if (test_set_buffer_pinned(bh))
 488                 gfs2_assert_withdraw(sdp, 0);
 489
 490         wait_on_buffer(bh);
 491
 492         /* If this buffer is in the AIL and it has already been written
 493            to in-place disk block, remove it from the AIL. */
 494
 495         gfs2_log_lock(sdp);
 496         if (bd->bd_ail && !buffer_in_io(bh))
 497                 list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
 498         gfs2_log_unlock(sdp);
 499
 500         clear_buffer_dirty(bh);
 501         wait_on_buffer(bh);
 502
 503         if (!buffer_uptodate(bh))
 504                 gfs2_io_error_bh(sdp, bh);
 505
 506         get_bh(bh);
 507 }
 508
 509 /**
 510  * gfs2_unpin - Unpin a buffer
 511  * @sdp: the filesystem the buffer belongs to
 512  * @bh: The buffer to unpin
 513  * @ai:
 514  *
 515  */
 516
 517 void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
 518                 struct gfs2_ail *ai)
 519 {
 520         struct gfs2_bufdata *bd = bh->b_private;
 521
 522         gfs2_assert_withdraw(sdp, buffer_uptodate(bh));
 523
 524         if (!buffer_pinned(bh))
 525                 gfs2_assert_withdraw(sdp, 0);
 526
 527         mark_buffer_dirty(bh);
 528         clear_buffer_pinned(bh);
 529
 530         gfs2_log_lock(sdp);
 531         if (bd->bd_ail) {
 532                 list_del(&bd->bd_ail_st_list);
 533                 brelse(bh);
 534         } else {
 535                 struct gfs2_glock *gl = bd->bd_gl;
 536                 list_add(&bd->bd_ail_gl_list, &gl->gl_ail_list);
 537                 atomic_inc(&gl->gl_ail_count);
 538         }
 539         bd->bd_ail = ai;
 540         list_add(&bd->bd_ail_st_list, &ai->ai_ail1_list);
 541         gfs2_log_unlock(sdp);
 542 }
 543
 544 /**
 545  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 546  * @ip: the inode who owns the buffers
 547  * @bstart: the first buffer in the run
 548  * @blen: the number of buffers in the run
 549  *
 550  */
 551
 552 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
 553 {
 554         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 555         struct inode *aspace = ip->i_gl->gl_aspace;
 556         struct buffer_head *bh;
 557
 558         while (blen) {
 559                 bh = getbuf(sdp, aspace, bstart, NO_CREATE);
 560                 if (bh) {
 561                         struct gfs2_bufdata *bd = bh->b_private;
 562
 563                         if (test_clear_buffer_pinned(bh)) {
 564                                 struct gfs2_trans *tr = current->journal_info;
 565                                 gfs2_log_lock(sdp);
 566                                 list_del_init(&bd->bd_le.le_list);
 567                                 gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
 568                                 sdp->sd_log_num_buf--;
 569                                 gfs2_log_unlock(sdp);
 570                                 tr->tr_num_buf_rm++;
 571                                 brelse(bh);
 572                         }
 573                         if (bd) {
 574                                 gfs2_log_lock(sdp);
 575                                 if (bd->bd_ail) {
 576                                         u64 blkno = bh->b_blocknr;
 577                                         bd->bd_ail = NULL;
 578                                         list_del(&bd->bd_ail_st_list);
 579                                         list_del(&bd->bd_ail_gl_list);
 580                                         atomic_dec(&bd->bd_gl->gl_ail_count);
 581                                         brelse(bh);
 582                                         gfs2_log_unlock(sdp);
 583                                         gfs2_trans_add_revoke(sdp, blkno);
 584                                 } else
 585                                         gfs2_log_unlock(sdp);
 586                         }
 587
 588                         lock_buffer(bh);
 589                         clear_buffer_dirty(bh);
 590                         clear_buffer_uptodate(bh);
 591                         unlock_buffer(bh);
 592
 593                         brelse(bh);
 594                 }
 595
 596                 bstart++;
 597                 blen--;
 598         }
 599 }
 600
 601 /**
 602  * gfs2_meta_cache_flush - get rid of any references on buffers for this inode
 603  * @ip: The GFS2 inode
 604  *
 605  * This releases buffers that are in the most-recently-used array of
 606  * blocks used for indirect block addressing for this inode.
 607  */
 608
 609 void gfs2_meta_cache_flush(struct gfs2_inode *ip)
 610 {
 611         struct buffer_head **bh_slot;
 612         unsigned int x;
 613
 614         spin_lock(&ip->i_spin);
 615
 616         for (x = 0; x < GFS2_MAX_META_HEIGHT; x++) {
 617                 bh_slot = &ip->i_cache[x];
 618                 if (!*bh_slot)
 619                         break;
 620                 brelse(*bh_slot);
 621                 *bh_slot = NULL;
 622         }
 623
 624         spin_unlock(&ip->i_spin);
 625 }
 626
 627 /**
 628  * gfs2_meta_indirect_buffer - Get a metadata buffer
 629  * @ip: The GFS2 inode
 630  * @height: The level of this buf in the metadata (indir addr) tree (if any)
 631  * @num: The block number (device relative) of the buffer
 632  * @new: Non-zero if we may create a new buffer
 633  * @bhp: the buffer is returned here
 634  *
 635  * Try to use the gfs2_inode's MRU metadata tree cache.
 636  *
 637  * Returns: errno
 638  */
 639
 640 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
 641                               int new, struct buffer_head **bhp)
 642 {
 643         struct buffer_head *bh, **bh_slot = ip->i_cache + height;
 644         int error;
 645
 646         spin_lock(&ip->i_spin);
 647         bh = *bh_slot;
 648         if (bh) {
 649                 if (bh->b_blocknr == num)
 650                         get_bh(bh);
 651                 else
 652                         bh = NULL;
 653         }
 654         spin_unlock(&ip->i_spin);
 655
 656         if (bh) {
 657                 if (new)
 658                         meta_prep_new(bh);
 659                 else {
 660                         error = gfs2_meta_reread(GFS2_SB(&ip->i_inode), bh,
 661                                                  DIO_START | DIO_WAIT);
 662                         if (error) {
 663                                 brelse(bh);
 664                                 return error;
 665                         }
 666                 }
 667         } else {
 668                 if (new)
 669                         bh = gfs2_meta_new(ip->i_gl, num);
 670                 else {
 671                         error = gfs2_meta_read(ip->i_gl, num,
 672                                                DIO_START | DIO_WAIT, &bh);
 673                         if (error)
 674                                 return error;
 675                 }
 676
 677                 spin_lock(&ip->i_spin);
 678                 if (*bh_slot != bh) {
 679                         brelse(*bh_slot);
 680                         *bh_slot = bh;
 681                         get_bh(bh);
 682                 }
 683                 spin_unlock(&ip->i_spin);
 684         }
 685
 686         if (new) {
 687                 if (gfs2_assert_warn(GFS2_SB(&ip->i_inode), height)) {
 688                         brelse(bh);
 689                         return -EIO;
 690                 }
 691                 gfs2_trans_add_bh(ip->i_gl, bh, 1);
 692                 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
 693                 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
 694
 695         } else if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh,
 696                              (height) ? GFS2_METATYPE_IN : GFS2_METATYPE_DI)) {
 697                 brelse(bh);
 698                 return -EIO;
 699         }
 700
 701         *bhp = bh;
 702
 703         return 0;
 704 }
 705
 706 /**
 707  * gfs2_meta_ra - start readahead on an extent of a file
 708  * @gl: the glock the blocks belong to
 709  * @dblock: the starting disk block
 710  * @extlen: the number of blocks in the extent
 711  *
 712  */
 713
 714 void gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
 715 {
 716         struct gfs2_sbd *sdp = gl->gl_sbd;
 717         struct inode *aspace = gl->gl_aspace;
 718         struct buffer_head *first_bh, *bh;
 719         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 720                           sdp->sd_sb.sb_bsize_shift;
 721         int error;
 722
 723         if (!extlen || !max_ra)
 724                 return;
 725         if (extlen > max_ra)
 726                 extlen = max_ra;
 727
 728         first_bh = getbuf(sdp, aspace, dblock, CREATE);
 729
 730         if (buffer_uptodate(first_bh))
 731                 goto out;
 732         if (!buffer_locked(first_bh)) {
 733                 error = gfs2_meta_reread(sdp, first_bh, DIO_START);
 734                 if (error)
 735                         goto out;
 736         }
 737
 738         dblock++;
 739         extlen--;
 740
 741         while (extlen) {
 742                 bh = getbuf(sdp, aspace, dblock, CREATE);
 743
 744                 if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
 745                         error = gfs2_meta_reread(sdp, bh, DIO_START);
 746                         brelse(bh);
 747                         if (error)
 748                                 goto out;
 749                 } else
 750                         brelse(bh);
 751
 752                 dblock++;
 753                 extlen--;
 754
 755                 if (buffer_uptodate(first_bh))
 756                         break;
 757         }
 758
 759 out:
 760         brelse(first_bh);
 761 }
 762
 763 /**
 764  * gfs2_meta_syncfs - sync all the buffers in a filesystem
 765  * @sdp: the filesystem
 766  *
 767  */
 768
 769 void gfs2_meta_syncfs(struct gfs2_sbd *sdp)
 770 {
 771         gfs2_log_flush(sdp, NULL);
 772         for (;;) {
 773                 gfs2_ail1_start(sdp, DIO_ALL);
 774                 if (gfs2_ail1_empty(sdp, DIO_ALL))
 775                         break;
 776                 msleep(10);
 777         }
 778 }
 779