git.oblomov.eu Git - linux-2.6/blob - fs/gfs2/ops_address.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 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/pagemap.h>
  16 #include <linux/pagevec.h>
  17 #include <linux/mpage.h>
  18 #include <linux/fs.h>
  19 #include <linux/gfs2_ondisk.h>
  20
  21 #include "gfs2.h"
  22 #include "lm_interface.h"
  23 #include "incore.h"
  24 #include "bmap.h"
  25 #include "glock.h"
  26 #include "inode.h"
  27 #include "log.h"
  28 #include "meta_io.h"
  29 #include "ops_address.h"
  30 #include "page.h"
  31 #include "quota.h"
  32 #include "trans.h"
  33 #include "rgrp.h"
  34 #include "ops_file.h"
  35 #include "util.h"
  36
  37 /**
  38  * gfs2_get_block - Fills in a buffer head with details about a block
  39  * @inode: The inode
  40  * @lblock: The block number to look up
  41  * @bh_result: The buffer head to return the result in
  42  * @create: Non-zero if we may add block to the file
  43  *
  44  * Returns: errno
  45  */
  46
  47 int gfs2_get_block(struct inode *inode, sector_t lblock,
  48                    struct buffer_head *bh_result, int create)
  49 {
  50         int new = create;
  51         uint64_t dblock;
  52         int error;
  53         int boundary;
  54
  55         error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary);
  56         if (error)
  57                 return error;
  58
  59         if (!dblock)
  60                 return 0;
  61
  62         map_bh(bh_result, inode->i_sb, dblock);
  63         if (new)
  64                 set_buffer_new(bh_result);
  65         if (boundary)
  66                 set_buffer_boundary(bh_result);
  67
  68         return 0;
  69 }
  70
  71 /**
  72  * get_block_noalloc - Fills in a buffer head with details about a block
  73  * @inode: The inode
  74  * @lblock: The block number to look up
  75  * @bh_result: The buffer head to return the result in
  76  * @create: Non-zero if we may add block to the file
  77  *
  78  * Returns: errno
  79  */
  80
  81 static int get_block_noalloc(struct inode *inode, sector_t lblock,
  82                              struct buffer_head *bh_result, int create)
  83 {
  84         int new = 0;
  85         uint64_t dblock;
  86         int error;
  87         int boundary;
  88
  89         error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary);
  90         if (error)
  91                 return error;
  92
  93         if (dblock)
  94                 map_bh(bh_result, inode->i_sb, dblock);
  95         else if (gfs2_assert_withdraw(GFS2_SB(inode), !create))
  96                 error = -EIO;
  97         if (boundary)
  98                 set_buffer_boundary(bh_result);
  99
 100         return error;
 101 }
 102
 103 /**
 104  * gfs2_writepage - Write complete page
 105  * @page: Page to write
 106  *
 107  * Returns: errno
 108  *
 109  * Some of this is copied from block_write_full_page() although we still
 110  * call it to do most of the work.
 111  */
 112
 113 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 114 {
 115         struct inode *inode = page->mapping->host;
 116         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 117         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 118         loff_t i_size = i_size_read(inode);
 119         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 120         unsigned offset;
 121         int error;
 122         int done_trans = 0;
 123
 124         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
 125                 unlock_page(page);
 126                 return -EIO;
 127         }
 128         if (current->journal_info)
 129                 goto out_ignore;
 130
 131         /* Is the page fully outside i_size? (truncate in progress) */
 132         offset = i_size & (PAGE_CACHE_SIZE-1);
 133         if (page->index > end_index || (page->index == end_index && !offset)) {
 134                 page->mapping->a_ops->invalidatepage(page, 0);
 135                 unlock_page(page);
 136                 return 0; /* don't care */
 137         }
 138
 139         if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) {
 140                 error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 141                 if (error)
 142                         goto out_ignore;
 143                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
 144                 done_trans = 1;
 145         }
 146         error = block_write_full_page(page, get_block_noalloc, wbc);
 147         if (done_trans)
 148                 gfs2_trans_end(sdp);
 149         gfs2_meta_cache_flush(ip);
 150         return error;
 151
 152 out_ignore:
 153         redirty_page_for_writepage(wbc, page);
 154         unlock_page(page);
 155         return 0;
 156 }
 157
 158 static int zero_readpage(struct page *page)
 159 {
 160         void *kaddr;
 161
 162         kaddr = kmap_atomic(page, KM_USER0);
 163         memset(kaddr, 0, PAGE_CACHE_SIZE);
 164         kunmap_atomic(page, KM_USER0);
 165
 166         SetPageUptodate(page);
 167
 168         return 0;
 169 }
 170
 171 /**
 172  * stuffed_readpage - Fill in a Linux page with stuffed file data
 173  * @ip: the inode
 174  * @page: the page
 175  *
 176  * Returns: errno
 177  */
 178
 179 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 180 {
 181         struct buffer_head *dibh;
 182         void *kaddr;
 183         int error;
 184
 185         /* Only the first page of a stuffed file might contain data */
 186         if (unlikely(page->index))
 187                 return zero_readpage(page);
 188
 189         error = gfs2_meta_inode_buffer(ip, &dibh);
 190         if (error)
 191                 return error;
 192
 193         kaddr = kmap_atomic(page, KM_USER0);
 194         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
 195                ip->i_di.di_size);
 196         memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
 197         kunmap_atomic(page, KM_USER0);
 198
 199         brelse(dibh);
 200
 201         SetPageUptodate(page);
 202
 203         return 0;
 204 }
 205
 206
 207 /**
 208  * gfs2_readpage - readpage with locking
 209  * @file: The file to read a page for. N.B. This may be NULL if we are
 210  * reading an internal file.
 211  * @page: The page to read
 212  *
 213  * Returns: errno
 214  */
 215
 216 static int gfs2_readpage(struct file *file, struct page *page)
 217 {
 218         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 219         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 220         struct gfs2_holder gh;
 221         int error;
 222
 223         if (likely(file != &gfs2_internal_file_sentinal)) {
 224                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh);
 225                 error = gfs2_glock_nq_m_atime(1, &gh);
 226                 if (unlikely(error))
 227                         goto out_unlock;
 228         }
 229
 230         if (gfs2_is_stuffed(ip)) {
 231                 error = stuffed_readpage(ip, page);
 232                 unlock_page(page);
 233         } else
 234                 error = mpage_readpage(page, gfs2_get_block);
 235
 236         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 237                 error = -EIO;
 238
 239         if (file != &gfs2_internal_file_sentinal) {
 240                 gfs2_glock_dq_m(1, &gh);
 241                 gfs2_holder_uninit(&gh);
 242         }
 243 out:
 244         return error;
 245 out_unlock:
 246         unlock_page(page);
 247         if (file != &gfs2_internal_file_sentinal)
 248                 gfs2_holder_uninit(&gh);
 249         goto out;
 250 }
 251
 252 #define list_to_page(head) (list_entry((head)->prev, struct page, lru))
 253
 254 /**
 255  * gfs2_readpages - Read a bunch of pages at once
 256  *
 257  * Some notes:
 258  * 1. This is only for readahead, so we can simply ignore any things
 259  *    which are slightly inconvenient (such as locking conflicts between
 260  *    the page lock and the glock) and return having done no I/O. Its
 261  *    obviously not something we'd want to do on too regular a basis.
 262  *    Any I/O we ignore at this time will be done via readpage later.
 263  * 2. We have to handle stuffed files here too.
 264  * 3. mpage_readpages() does most of the heavy lifting in the common case.
 265  * 4. gfs2_get_block() is relied upon to set BH_Boundary in the right places.
 266  * 5. We use LM_FLAG_TRY_1CB here, effectively we then have lock-ahead as
 267  *    well as read-ahead.
 268  */
 269 static int gfs2_readpages(struct file *file, struct address_space *mapping,
 270                           struct list_head *pages, unsigned nr_pages)
 271 {
 272         struct inode *inode = mapping->host;
 273         struct gfs2_inode *ip = GFS2_I(inode);
 274         struct gfs2_sbd *sdp = GFS2_SB(inode);
 275         struct gfs2_holder gh;
 276         unsigned page_idx;
 277         int ret;
 278
 279         if (likely(file != &gfs2_internal_file_sentinal)) {
 280                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
 281                                  LM_FLAG_TRY_1CB|GL_ATIME|GL_AOP, &gh);
 282                 ret = gfs2_glock_nq_m_atime(1, &gh);
 283                 if (ret == GLR_TRYFAILED)
 284                         goto out_noerror;
 285                 if (unlikely(ret))
 286                         goto out_unlock;
 287         }
 288
 289         if (gfs2_is_stuffed(ip)) {
 290                 struct pagevec lru_pvec;
 291                 pagevec_init(&lru_pvec, 0);
 292                 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 293                         struct page *page = list_to_page(pages);
 294                         list_del(&page->lru);
 295                         if (!add_to_page_cache(page, mapping,
 296                                                page->index, GFP_KERNEL)) {
 297                                 ret = stuffed_readpage(ip, page);
 298                                 unlock_page(page);
 299                                 if (!pagevec_add(&lru_pvec, page))
 300                                          __pagevec_lru_add(&lru_pvec);
 301                         }
 302                         page_cache_release(page);
 303                 }
 304                 pagevec_lru_add(&lru_pvec);
 305                 ret = 0;
 306         } else {
 307                 /* What we really want to do .... */
 308                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
 309         }
 310
 311         if (likely(file != &gfs2_internal_file_sentinal)) {
 312                 gfs2_glock_dq_m(1, &gh);
 313                 gfs2_holder_uninit(&gh);
 314         }
 315 out:
 316         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 317                 ret = -EIO;
 318         return ret;
 319 out_noerror:
 320         ret = 0;
 321 out_unlock:
 322         /* unlock all pages, we can't do any I/O right now */
 323         for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 324                 struct page *page = list_to_page(pages);
 325                 list_del(&page->lru);
 326                 unlock_page(page);
 327                 page_cache_release(page);
 328         }
 329         if (likely(file != &gfs2_internal_file_sentinal))
 330                 gfs2_holder_uninit(&gh);
 331         goto out;
 332 }
 333
 334 /**
 335  * gfs2_prepare_write - Prepare to write a page to a file
 336  * @file: The file to write to
 337  * @page: The page which is to be prepared for writing
 338  * @from: From (byte range within page)
 339  * @to: To (byte range within page)
 340  *
 341  * Returns: errno
 342  */
 343
 344 static int gfs2_prepare_write(struct file *file, struct page *page,
 345                               unsigned from, unsigned to)
 346 {
 347         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 348         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 349         unsigned int data_blocks, ind_blocks, rblocks;
 350         int alloc_required;
 351         int error = 0;
 352         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
 353         loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 354         struct gfs2_alloc *al;
 355
 356         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|GL_AOP, &ip->i_gh);
 357         error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
 358         if (error)
 359                 goto out_uninit;
 360
 361         gfs2_write_calc_reserv(ip, to - from, &data_blocks, &ind_blocks);
 362
 363         error = gfs2_write_alloc_required(ip, pos, from - to, &alloc_required);
 364         if (error)
 365                 goto out_unlock;
 366
 367
 368         if (alloc_required) {
 369                 al = gfs2_alloc_get(ip);
 370
 371                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 372                 if (error)
 373                         goto out_alloc_put;
 374
 375                 error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
 376                 if (error)
 377                         goto out_qunlock;
 378
 379                 al->al_requested = data_blocks + ind_blocks;
 380                 error = gfs2_inplace_reserve(ip);
 381                 if (error)
 382                         goto out_qunlock;
 383         }
 384
 385         rblocks = RES_DINODE + ind_blocks;
 386         if (gfs2_is_jdata(ip))
 387                 rblocks += data_blocks ? data_blocks : 1;
 388         if (ind_blocks || data_blocks)
 389                 rblocks += RES_STATFS + RES_QUOTA;
 390
 391         error = gfs2_trans_begin(sdp, rblocks, 0);
 392         if (error)
 393                 goto out;
 394
 395         if (gfs2_is_stuffed(ip)) {
 396                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 397                         error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page,
 398                                                     page);
 399                         if (error == 0)
 400                                 goto prepare_write;
 401                 } else if (!PageUptodate(page))
 402                         error = stuffed_readpage(ip, page);
 403                 goto out;
 404         }
 405
 406 prepare_write:
 407         error = block_prepare_write(page, from, to, gfs2_get_block);
 408
 409 out:
 410         if (error) {
 411                 gfs2_trans_end(sdp);
 412                 if (alloc_required) {
 413                         gfs2_inplace_release(ip);
 414 out_qunlock:
 415                         gfs2_quota_unlock(ip);
 416 out_alloc_put:
 417                         gfs2_alloc_put(ip);
 418                 }
 419 out_unlock:
 420                 gfs2_glock_dq_m(1, &ip->i_gh);
 421 out_uninit:
 422                 gfs2_holder_uninit(&ip->i_gh);
 423         }
 424
 425         return error;
 426 }
 427
 428 /**
 429  * gfs2_commit_write - Commit write to a file
 430  * @file: The file to write to
 431  * @page: The page containing the data
 432  * @from: From (byte range within page)
 433  * @to: To (byte range within page)
 434  *
 435  * Returns: errno
 436  */
 437
 438 static int gfs2_commit_write(struct file *file, struct page *page,
 439                              unsigned from, unsigned to)
 440 {
 441         struct inode *inode = page->mapping->host;
 442         struct gfs2_inode *ip = GFS2_I(inode);
 443         struct gfs2_sbd *sdp = GFS2_SB(inode);
 444         int error = -EOPNOTSUPP;
 445         struct buffer_head *dibh;
 446         struct gfs2_alloc *al = &ip->i_alloc;;
 447
 448         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 449                 goto fail_nounlock;
 450
 451         error = gfs2_meta_inode_buffer(ip, &dibh);
 452         if (error)
 453                 goto fail_endtrans;
 454
 455         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 456
 457         if (gfs2_is_stuffed(ip)) {
 458                 uint64_t file_size;
 459                 void *kaddr;
 460
 461                 file_size = ((uint64_t)page->index << PAGE_CACHE_SHIFT) + to;
 462
 463                 kaddr = kmap_atomic(page, KM_USER0);
 464                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 465                        (char *)kaddr + from, to - from);
 466                 kunmap_atomic(page, KM_USER0);
 467
 468                 SetPageUptodate(page);
 469
 470                 if (inode->i_size < file_size)
 471                         i_size_write(inode, file_size);
 472         } else {
 473                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED ||
 474                     gfs2_is_jdata(ip))
 475                         gfs2_page_add_databufs(ip, page, from, to);
 476                 error = generic_commit_write(file, page, from, to);
 477                 if (error)
 478                         goto fail;
 479         }
 480
 481         if (ip->i_di.di_size < inode->i_size)
 482                 ip->i_di.di_size = inode->i_size;
 483
 484         gfs2_dinode_out(&ip->i_di, dibh->b_data);
 485         brelse(dibh);
 486         gfs2_trans_end(sdp);
 487         if (al->al_requested) {
 488                 gfs2_inplace_release(ip);
 489                 gfs2_quota_unlock(ip);
 490                 gfs2_alloc_put(ip);
 491         }
 492         gfs2_glock_dq_m(1, &ip->i_gh);
 493         gfs2_holder_uninit(&ip->i_gh);
 494         return 0;
 495
 496 fail:
 497         brelse(dibh);
 498 fail_endtrans:
 499         gfs2_trans_end(sdp);
 500         if (al->al_requested) {
 501                 gfs2_inplace_release(ip);
 502                 gfs2_quota_unlock(ip);
 503                 gfs2_alloc_put(ip);
 504         }
 505         gfs2_glock_dq_m(1, &ip->i_gh);
 506         gfs2_holder_uninit(&ip->i_gh);
 507 fail_nounlock:
 508         ClearPageUptodate(page);
 509         return error;
 510 }
 511
 512 /**
 513  * gfs2_bmap - Block map function
 514  * @mapping: Address space info
 515  * @lblock: The block to map
 516  *
 517  * Returns: The disk address for the block or 0 on hole or error
 518  */
 519
 520 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 521 {
 522         struct gfs2_inode *ip = GFS2_I(mapping->host);
 523         struct gfs2_holder i_gh;
 524         sector_t dblock = 0;
 525         int error;
 526
 527         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 528         if (error)
 529                 return 0;
 530
 531         if (!gfs2_is_stuffed(ip))
 532                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 533
 534         gfs2_glock_dq_uninit(&i_gh);
 535
 536         return dblock;
 537 }
 538
 539 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 540 {
 541         struct gfs2_bufdata *bd;
 542
 543         gfs2_log_lock(sdp);
 544         bd = bh->b_private;
 545         if (bd) {
 546                 bd->bd_bh = NULL;
 547                 bh->b_private = NULL;
 548                 gfs2_log_unlock(sdp);
 549                 brelse(bh);
 550         } else
 551                 gfs2_log_unlock(sdp);
 552
 553         lock_buffer(bh);
 554         clear_buffer_dirty(bh);
 555         bh->b_bdev = NULL;
 556         clear_buffer_mapped(bh);
 557         clear_buffer_req(bh);
 558         clear_buffer_new(bh);
 559         clear_buffer_delay(bh);
 560         unlock_buffer(bh);
 561 }
 562
 563 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 564 {
 565         struct gfs2_sbd *sdp = page->mapping->host->i_sb->s_fs_info;
 566         struct buffer_head *head, *bh, *next;
 567         unsigned int curr_off = 0;
 568
 569         BUG_ON(!PageLocked(page));
 570         if (!page_has_buffers(page))
 571                 return;
 572
 573         bh = head = page_buffers(page);
 574         do {
 575                 unsigned int next_off = curr_off + bh->b_size;
 576                 next = bh->b_this_page;
 577
 578                 if (offset <= curr_off)
 579                         discard_buffer(sdp, bh);
 580
 581                 curr_off = next_off;
 582                 bh = next;
 583         } while (bh != head);
 584
 585         if (!offset)
 586                 try_to_release_page(page, 0);
 587
 588         return;
 589 }
 590
 591 static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov,
 592                                     loff_t offset, unsigned long nr_segs)
 593 {
 594         struct file *file = iocb->ki_filp;
 595         struct inode *inode = file->f_mapping->host;
 596         struct gfs2_inode *ip = GFS2_I(inode);
 597         struct gfs2_holder gh;
 598         int rv;
 599
 600         /*
 601          * Shared lock, even though its write, since we do no allocation
 602          * on this path. All we need change is atime.
 603          */
 604         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 605         rv = gfs2_glock_nq_m_atime(1, &gh);
 606         if (rv)
 607                 goto out;
 608
 609         /*
 610          * Should we return an error here? I can't see that O_DIRECT for
 611          * a journaled file makes any sense. For now we'll silently fall
 612          * back to buffered I/O, likewise we do the same for stuffed
 613          * files since they are (a) small and (b) unaligned.
 614          */
 615         if (gfs2_is_jdata(ip))
 616                 goto out;
 617
 618         if (gfs2_is_stuffed(ip))
 619                 goto out;
 620
 621         rv = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev,
 622                                   iov, offset, nr_segs, gfs2_get_block,
 623                                   NULL, DIO_OWN_LOCKING);
 624 out:
 625         gfs2_glock_dq_m(1, &gh);
 626         gfs2_holder_uninit(&gh);
 627
 628         return rv;
 629 }
 630
 631 /**
 632  * gfs2_direct_IO
 633  *
 634  * This is called with a shared lock already held for the read path.
 635  * Currently, no locks are held when the write path is called.
 636  */
 637 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 638                               const struct iovec *iov, loff_t offset,
 639                               unsigned long nr_segs)
 640 {
 641         struct file *file = iocb->ki_filp;
 642         struct inode *inode = file->f_mapping->host;
 643         struct gfs2_inode *ip = GFS2_I(inode);
 644         struct gfs2_sbd *sdp = GFS2_SB(inode);
 645
 646         if (rw == WRITE)
 647                 return gfs2_direct_IO_write(iocb, iov, offset, nr_segs);
 648
 649         if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) ||
 650             gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
 651                 return -EINVAL;
 652
 653         return __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov,
 654                                     offset, nr_segs, gfs2_get_block, NULL,
 655                                     DIO_OWN_LOCKING);
 656 }
 657
 658 struct address_space_operations gfs2_file_aops = {
 659         .writepage = gfs2_writepage,
 660         .readpage = gfs2_readpage,
 661         .readpages = gfs2_readpages,
 662         .sync_page = block_sync_page,
 663         .prepare_write = gfs2_prepare_write,
 664         .commit_write = gfs2_commit_write,
 665         .bmap = gfs2_bmap,
 666         .invalidatepage = gfs2_invalidatepage,
 667         .direct_IO = gfs2_direct_IO,
 668 };
 669