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) 2004-2008 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/pagemap.h>
  16 #include <linux/pagevec.h>
  17 #include <linux/mpage.h>
  18 #include <linux/fs.h>
  19 #include <linux/writeback.h>
  20 #include <linux/swap.h>
  21 #include <linux/gfs2_ondisk.h>
  22 #include <linux/lm_interface.h>
  23 #include <linux/backing-dev.h>
  24
  25 #include "gfs2.h"
  26 #include "incore.h"
  27 #include "bmap.h"
  28 #include "glock.h"
  29 #include "inode.h"
  30 #include "log.h"
  31 #include "meta_io.h"
  32 #include "ops_address.h"
  33 #include "quota.h"
  34 #include "trans.h"
  35 #include "rgrp.h"
  36 #include "super.h"
  37 #include "util.h"
  38 #include "glops.h"
  39
  40
  41 static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
  42                                    unsigned int from, unsigned int to)
  43 {
  44         struct buffer_head *head = page_buffers(page);
  45         unsigned int bsize = head->b_size;
  46         struct buffer_head *bh;
  47         unsigned int start, end;
  48
  49         for (bh = head, start = 0; bh != head || !start;
  50              bh = bh->b_this_page, start = end) {
  51                 end = start + bsize;
  52                 if (end <= from || start >= to)
  53                         continue;
  54                 if (gfs2_is_jdata(ip))
  55                         set_buffer_uptodate(bh);
  56                 gfs2_trans_add_bh(ip->i_gl, bh, 0);
  57         }
  58 }
  59
  60 /**
  61  * gfs2_get_block_noalloc - Fills in a buffer head with details about a block
  62  * @inode: The inode
  63  * @lblock: The block number to look up
  64  * @bh_result: The buffer head to return the result in
  65  * @create: Non-zero if we may add block to the file
  66  *
  67  * Returns: errno
  68  */
  69
  70 static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
  71                                   struct buffer_head *bh_result, int create)
  72 {
  73         int error;
  74
  75         error = gfs2_block_map(inode, lblock, bh_result, 0);
  76         if (error)
  77                 return error;
  78         if (!buffer_mapped(bh_result))
  79                 return -EIO;
  80         return 0;
  81 }
  82
  83 static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
  84                                  struct buffer_head *bh_result, int create)
  85 {
  86         return gfs2_block_map(inode, lblock, bh_result, 0);
  87 }
  88
  89 /**
  90  * gfs2_writepage_common - Common bits of writepage
  91  * @page: The page to be written
  92  * @wbc: The writeback control
  93  *
  94  * Returns: 1 if writepage is ok, otherwise an error code or zero if no error.
  95  */
  96
  97 static int gfs2_writepage_common(struct page *page,
  98                                  struct writeback_control *wbc)
  99 {
 100         struct inode *inode = page->mapping->host;
 101         struct gfs2_inode *ip = GFS2_I(inode);
 102         struct gfs2_sbd *sdp = GFS2_SB(inode);
 103         loff_t i_size = i_size_read(inode);
 104         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 105         unsigned offset;
 106
 107         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
 108                 goto out;
 109         if (current->journal_info)
 110                 goto redirty;
 111         /* Is the page fully outside i_size? (truncate in progress) */
 112         offset = i_size & (PAGE_CACHE_SIZE-1);
 113         if (page->index > end_index || (page->index == end_index && !offset)) {
 114                 page->mapping->a_ops->invalidatepage(page, 0);
 115                 goto out;
 116         }
 117         return 1;
 118 redirty:
 119         redirty_page_for_writepage(wbc, page);
 120 out:
 121         unlock_page(page);
 122         return 0;
 123 }
 124
 125 /**
 126  * gfs2_writeback_writepage - Write page for writeback mappings
 127  * @page: The page
 128  * @wbc: The writeback control
 129  *
 130  */
 131
 132 static int gfs2_writeback_writepage(struct page *page,
 133                                     struct writeback_control *wbc)
 134 {
 135         int ret;
 136
 137         ret = gfs2_writepage_common(page, wbc);
 138         if (ret <= 0)
 139                 return ret;
 140
 141         ret = mpage_writepage(page, gfs2_get_block_noalloc, wbc);
 142         if (ret == -EAGAIN)
 143                 ret = block_write_full_page(page, gfs2_get_block_noalloc, wbc);
 144         return ret;
 145 }
 146
 147 /**
 148  * gfs2_ordered_writepage - Write page for ordered data files
 149  * @page: The page to write
 150  * @wbc: The writeback control
 151  *
 152  */
 153
 154 static int gfs2_ordered_writepage(struct page *page,
 155                                   struct writeback_control *wbc)
 156 {
 157         struct inode *inode = page->mapping->host;
 158         struct gfs2_inode *ip = GFS2_I(inode);
 159         int ret;
 160
 161         ret = gfs2_writepage_common(page, wbc);
 162         if (ret <= 0)
 163                 return ret;
 164
 165         if (!page_has_buffers(page)) {
 166                 create_empty_buffers(page, inode->i_sb->s_blocksize,
 167                                      (1 << BH_Dirty)|(1 << BH_Uptodate));
 168         }
 169         gfs2_page_add_databufs(ip, page, 0, inode->i_sb->s_blocksize-1);
 170         return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
 171 }
 172
 173 /**
 174  * __gfs2_jdata_writepage - The core of jdata writepage
 175  * @page: The page to write
 176  * @wbc: The writeback control
 177  *
 178  * This is shared between writepage and writepages and implements the
 179  * core of the writepage operation. If a transaction is required then
 180  * PageChecked will have been set and the transaction will have
 181  * already been started before this is called.
 182  */
 183
 184 static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
 185 {
 186         struct inode *inode = page->mapping->host;
 187         struct gfs2_inode *ip = GFS2_I(inode);
 188         struct gfs2_sbd *sdp = GFS2_SB(inode);
 189
 190         if (PageChecked(page)) {
 191                 ClearPageChecked(page);
 192                 if (!page_has_buffers(page)) {
 193                         create_empty_buffers(page, inode->i_sb->s_blocksize,
 194                                              (1 << BH_Dirty)|(1 << BH_Uptodate));
 195                 }
 196                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
 197         }
 198         return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
 199 }
 200
 201 /**
 202  * gfs2_jdata_writepage - Write complete page
 203  * @page: Page to write
 204  *
 205  * Returns: errno
 206  *
 207  */
 208
 209 static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
 210 {
 211         struct inode *inode = page->mapping->host;
 212         struct gfs2_sbd *sdp = GFS2_SB(inode);
 213         int error;
 214         int done_trans = 0;
 215
 216         error = gfs2_writepage_common(page, wbc);
 217         if (error <= 0)
 218                 return error;
 219
 220         if (PageChecked(page)) {
 221                 if (wbc->sync_mode != WB_SYNC_ALL)
 222                         goto out_ignore;
 223                 error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 224                 if (error)
 225                         goto out_ignore;
 226                 done_trans = 1;
 227         }
 228         error = __gfs2_jdata_writepage(page, wbc);
 229         if (done_trans)
 230                 gfs2_trans_end(sdp);
 231         return error;
 232
 233 out_ignore:
 234         redirty_page_for_writepage(wbc, page);
 235         unlock_page(page);
 236         return 0;
 237 }
 238
 239 /**
 240  * gfs2_writeback_writepages - Write a bunch of dirty pages back to disk
 241  * @mapping: The mapping to write
 242  * @wbc: Write-back control
 243  *
 244  * For the data=writeback case we can already ignore buffer heads
 245  * and write whole extents at once. This is a big reduction in the
 246  * number of I/O requests we send and the bmap calls we make in this case.
 247  */
 248 static int gfs2_writeback_writepages(struct address_space *mapping,
 249                                      struct writeback_control *wbc)
 250 {
 251         return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
 252 }
 253
 254 /**
 255  * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
 256  * @mapping: The mapping
 257  * @wbc: The writeback control
 258  * @writepage: The writepage function to call for each page
 259  * @pvec: The vector of pages
 260  * @nr_pages: The number of pages to write
 261  *
 262  * Returns: non-zero if loop should terminate, zero otherwise
 263  */
 264
 265 static int gfs2_write_jdata_pagevec(struct address_space *mapping,
 266                                     struct writeback_control *wbc,
 267                                     struct pagevec *pvec,
 268                                     int nr_pages, pgoff_t end)
 269 {
 270         struct inode *inode = mapping->host;
 271         struct gfs2_sbd *sdp = GFS2_SB(inode);
 272         loff_t i_size = i_size_read(inode);
 273         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 274         unsigned offset = i_size & (PAGE_CACHE_SIZE-1);
 275         unsigned nrblocks = nr_pages * (PAGE_CACHE_SIZE/inode->i_sb->s_blocksize);
 276         struct backing_dev_info *bdi = mapping->backing_dev_info;
 277         int i;
 278         int ret;
 279
 280         ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
 281         if (ret < 0)
 282                 return ret;
 283
 284         for(i = 0; i < nr_pages; i++) {
 285                 struct page *page = pvec->pages[i];
 286
 287                 lock_page(page);
 288
 289                 if (unlikely(page->mapping != mapping)) {
 290                         unlock_page(page);
 291                         continue;
 292                 }
 293
 294                 if (!wbc->range_cyclic && page->index > end) {
 295                         ret = 1;
 296                         unlock_page(page);
 297                         continue;
 298                 }
 299
 300                 if (wbc->sync_mode != WB_SYNC_NONE)
 301                         wait_on_page_writeback(page);
 302
 303                 if (PageWriteback(page) ||
 304                     !clear_page_dirty_for_io(page)) {
 305                         unlock_page(page);
 306                         continue;
 307                 }
 308
 309                 /* Is the page fully outside i_size? (truncate in progress) */
 310                 if (page->index > end_index || (page->index == end_index && !offset)) {
 311                         page->mapping->a_ops->invalidatepage(page, 0);
 312                         unlock_page(page);
 313                         continue;
 314                 }
 315
 316                 ret = __gfs2_jdata_writepage(page, wbc);
 317
 318                 if (ret || (--(wbc->nr_to_write) <= 0))
 319                         ret = 1;
 320                 if (wbc->nonblocking && bdi_write_congested(bdi)) {
 321                         wbc->encountered_congestion = 1;
 322                         ret = 1;
 323                 }
 324
 325         }
 326         gfs2_trans_end(sdp);
 327         return ret;
 328 }
 329
 330 /**
 331  * gfs2_write_cache_jdata - Like write_cache_pages but different
 332  * @mapping: The mapping to write
 333  * @wbc: The writeback control
 334  * @writepage: The writepage function to call
 335  * @data: The data to pass to writepage
 336  *
 337  * The reason that we use our own function here is that we need to
 338  * start transactions before we grab page locks. This allows us
 339  * to get the ordering right.
 340  */
 341
 342 static int gfs2_write_cache_jdata(struct address_space *mapping,
 343                                   struct writeback_control *wbc)
 344 {
 345         struct backing_dev_info *bdi = mapping->backing_dev_info;
 346         int ret = 0;
 347         int done = 0;
 348         struct pagevec pvec;
 349         int nr_pages;
 350         pgoff_t index;
 351         pgoff_t end;
 352         int scanned = 0;
 353         int range_whole = 0;
 354
 355         if (wbc->nonblocking && bdi_write_congested(bdi)) {
 356                 wbc->encountered_congestion = 1;
 357                 return 0;
 358         }
 359
 360         pagevec_init(&pvec, 0);
 361         if (wbc->range_cyclic) {
 362                 index = mapping->writeback_index; /* Start from prev offset */
 363                 end = -1;
 364         } else {
 365                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
 366                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
 367                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
 368                         range_whole = 1;
 369                 scanned = 1;
 370         }
 371
 372 retry:
 373          while (!done && (index <= end) &&
 374                 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
 375                                                PAGECACHE_TAG_DIRTY,
 376                                                min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
 377                 scanned = 1;
 378                 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, end);
 379                 if (ret)
 380                         done = 1;
 381                 if (ret > 0)
 382                         ret = 0;
 383
 384                 pagevec_release(&pvec);
 385                 cond_resched();
 386         }
 387
 388         if (!scanned && !done) {
 389                 /*
 390                  * We hit the last page and there is more work to be done: wrap
 391                  * back to the start of the file
 392                  */
 393                 scanned = 1;
 394                 index = 0;
 395                 goto retry;
 396         }
 397
 398         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 399                 mapping->writeback_index = index;
 400         return ret;
 401 }
 402
 403
 404 /**
 405  * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
 406  * @mapping: The mapping to write
 407  * @wbc: The writeback control
 408  *
 409  */
 410
 411 static int gfs2_jdata_writepages(struct address_space *mapping,
 412                                  struct writeback_control *wbc)
 413 {
 414         struct gfs2_inode *ip = GFS2_I(mapping->host);
 415         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
 416         int ret;
 417
 418         ret = gfs2_write_cache_jdata(mapping, wbc);
 419         if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
 420                 gfs2_log_flush(sdp, ip->i_gl);
 421                 ret = gfs2_write_cache_jdata(mapping, wbc);
 422         }
 423         return ret;
 424 }
 425
 426 /**
 427  * stuffed_readpage - Fill in a Linux page with stuffed file data
 428  * @ip: the inode
 429  * @page: the page
 430  *
 431  * Returns: errno
 432  */
 433
 434 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 435 {
 436         struct buffer_head *dibh;
 437         void *kaddr;
 438         int error;
 439
 440         /*
 441          * Due to the order of unstuffing files and ->fault(), we can be
 442          * asked for a zero page in the case of a stuffed file being extended,
 443          * so we need to supply one here. It doesn't happen often.
 444          */
 445         if (unlikely(page->index)) {
 446                 zero_user(page, 0, PAGE_CACHE_SIZE);
 447                 return 0;
 448         }
 449
 450         error = gfs2_meta_inode_buffer(ip, &dibh);
 451         if (error)
 452                 return error;
 453
 454         kaddr = kmap_atomic(page, KM_USER0);
 455         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
 456                ip->i_di.di_size);
 457         memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
 458         kunmap_atomic(kaddr, KM_USER0);
 459         flush_dcache_page(page);
 460         brelse(dibh);
 461         SetPageUptodate(page);
 462
 463         return 0;
 464 }
 465
 466
 467 /**
 468  * __gfs2_readpage - readpage
 469  * @file: The file to read a page for
 470  * @page: The page to read
 471  *
 472  * This is the core of gfs2's readpage. Its used by the internal file
 473  * reading code as in that case we already hold the glock. Also its
 474  * called by gfs2_readpage() once the required lock has been granted.
 475  *
 476  */
 477
 478 static int __gfs2_readpage(void *file, struct page *page)
 479 {
 480         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 481         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 482         int error;
 483
 484         if (gfs2_is_stuffed(ip)) {
 485                 error = stuffed_readpage(ip, page);
 486                 unlock_page(page);
 487         } else {
 488                 error = mpage_readpage(page, gfs2_block_map);
 489         }
 490
 491         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 492                 return -EIO;
 493
 494         return error;
 495 }
 496
 497 /**
 498  * gfs2_readpage - read a page of a file
 499  * @file: The file to read
 500  * @page: The page of the file
 501  *
 502  * This deals with the locking required. We have to unlock and
 503  * relock the page in order to get the locking in the right
 504  * order.
 505  */
 506
 507 static int gfs2_readpage(struct file *file, struct page *page)
 508 {
 509         struct address_space *mapping = page->mapping;
 510         struct gfs2_inode *ip = GFS2_I(mapping->host);
 511         struct gfs2_holder gh;
 512         int error;
 513
 514         unlock_page(page);
 515         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 516         error = gfs2_glock_nq_atime(&gh);
 517         if (unlikely(error))
 518                 goto out;
 519         error = AOP_TRUNCATED_PAGE;
 520         lock_page(page);
 521         if (page->mapping == mapping && !PageUptodate(page))
 522                 error = __gfs2_readpage(file, page);
 523         else
 524                 unlock_page(page);
 525         gfs2_glock_dq(&gh);
 526 out:
 527         gfs2_holder_uninit(&gh);
 528         if (error && error != AOP_TRUNCATED_PAGE)
 529                 lock_page(page);
 530         return error;
 531 }
 532
 533 /**
 534  * gfs2_internal_read - read an internal file
 535  * @ip: The gfs2 inode
 536  * @ra_state: The readahead state (or NULL for no readahead)
 537  * @buf: The buffer to fill
 538  * @pos: The file position
 539  * @size: The amount to read
 540  *
 541  */
 542
 543 int gfs2_internal_read(struct gfs2_inode *ip, struct file_ra_state *ra_state,
 544                        char *buf, loff_t *pos, unsigned size)
 545 {
 546         struct address_space *mapping = ip->i_inode.i_mapping;
 547         unsigned long index = *pos / PAGE_CACHE_SIZE;
 548         unsigned offset = *pos & (PAGE_CACHE_SIZE - 1);
 549         unsigned copied = 0;
 550         unsigned amt;
 551         struct page *page;
 552         void *p;
 553
 554         do {
 555                 amt = size - copied;
 556                 if (offset + size > PAGE_CACHE_SIZE)
 557                         amt = PAGE_CACHE_SIZE - offset;
 558                 page = read_cache_page(mapping, index, __gfs2_readpage, NULL);
 559                 if (IS_ERR(page))
 560                         return PTR_ERR(page);
 561                 p = kmap_atomic(page, KM_USER0);
 562                 memcpy(buf + copied, p + offset, amt);
 563                 kunmap_atomic(p, KM_USER0);
 564                 mark_page_accessed(page);
 565                 page_cache_release(page);
 566                 copied += amt;
 567                 index++;
 568                 offset = 0;
 569         } while(copied < size);
 570         (*pos) += size;
 571         return size;
 572 }
 573
 574 /**
 575  * gfs2_readpages - Read a bunch of pages at once
 576  *
 577  * Some notes:
 578  * 1. This is only for readahead, so we can simply ignore any things
 579  *    which are slightly inconvenient (such as locking conflicts between
 580  *    the page lock and the glock) and return having done no I/O. Its
 581  *    obviously not something we'd want to do on too regular a basis.
 582  *    Any I/O we ignore at this time will be done via readpage later.
 583  * 2. We don't handle stuffed files here we let readpage do the honours.
 584  * 3. mpage_readpages() does most of the heavy lifting in the common case.
 585  * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
 586  */
 587
 588 static int gfs2_readpages(struct file *file, struct address_space *mapping,
 589                           struct list_head *pages, unsigned nr_pages)
 590 {
 591         struct inode *inode = mapping->host;
 592         struct gfs2_inode *ip = GFS2_I(inode);
 593         struct gfs2_sbd *sdp = GFS2_SB(inode);
 594         struct gfs2_holder gh;
 595         int ret;
 596
 597         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 598         ret = gfs2_glock_nq_atime(&gh);
 599         if (unlikely(ret))
 600                 goto out_uninit;
 601         if (!gfs2_is_stuffed(ip))
 602                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
 603         gfs2_glock_dq(&gh);
 604 out_uninit:
 605         gfs2_holder_uninit(&gh);
 606         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 607                 ret = -EIO;
 608         return ret;
 609 }
 610
 611 /**
 612  * gfs2_write_begin - Begin to write to a file
 613  * @file: The file to write to
 614  * @mapping: The mapping in which to write
 615  * @pos: The file offset at which to start writing
 616  * @len: Length of the write
 617  * @flags: Various flags
 618  * @pagep: Pointer to return the page
 619  * @fsdata: Pointer to return fs data (unused by GFS2)
 620  *
 621  * Returns: errno
 622  */
 623
 624 static int gfs2_write_begin(struct file *file, struct address_space *mapping,
 625                             loff_t pos, unsigned len, unsigned flags,
 626                             struct page **pagep, void **fsdata)
 627 {
 628         struct gfs2_inode *ip = GFS2_I(mapping->host);
 629         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
 630         unsigned int data_blocks, ind_blocks, rblocks;
 631         int alloc_required;
 632         int error = 0;
 633         struct gfs2_alloc *al;
 634         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 635         unsigned from = pos & (PAGE_CACHE_SIZE - 1);
 636         unsigned to = from + len;
 637         struct page *page;
 638
 639         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME, &ip->i_gh);
 640         error = gfs2_glock_nq_atime(&ip->i_gh);
 641         if (unlikely(error))
 642                 goto out_uninit;
 643
 644         gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
 645         error = gfs2_write_alloc_required(ip, pos, len, &alloc_required);
 646         if (error)
 647                 goto out_unlock;
 648
 649         if (alloc_required) {
 650                 al = gfs2_alloc_get(ip);
 651                 if (!al) {
 652                         error = -ENOMEM;
 653                         goto out_unlock;
 654                 }
 655
 656                 error = gfs2_quota_lock_check(ip);
 657                 if (error)
 658                         goto out_alloc_put;
 659
 660                 al->al_requested = data_blocks + ind_blocks;
 661                 error = gfs2_inplace_reserve(ip);
 662                 if (error)
 663                         goto out_qunlock;
 664         }
 665
 666         rblocks = RES_DINODE + ind_blocks;
 667         if (gfs2_is_jdata(ip))
 668                 rblocks += data_blocks ? data_blocks : 1;
 669         if (ind_blocks || data_blocks)
 670                 rblocks += RES_STATFS + RES_QUOTA;
 671
 672         error = gfs2_trans_begin(sdp, rblocks,
 673                                  PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize);
 674         if (error)
 675                 goto out_trans_fail;
 676
 677         error = -ENOMEM;
 678         page = __grab_cache_page(mapping, index);
 679         *pagep = page;
 680         if (unlikely(!page))
 681                 goto out_endtrans;
 682
 683         if (gfs2_is_stuffed(ip)) {
 684                 error = 0;
 685                 if (pos + len > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 686                         error = gfs2_unstuff_dinode(ip, page);
 687                         if (error == 0)
 688                                 goto prepare_write;
 689                 } else if (!PageUptodate(page)) {
 690                         error = stuffed_readpage(ip, page);
 691                 }
 692                 goto out;
 693         }
 694
 695 prepare_write:
 696         error = block_prepare_write(page, from, to, gfs2_block_map);
 697 out:
 698         if (error == 0)
 699                 return 0;
 700
 701         page_cache_release(page);
 702         if (pos + len > ip->i_inode.i_size)
 703                 vmtruncate(&ip->i_inode, ip->i_inode.i_size);
 704 out_endtrans:
 705         gfs2_trans_end(sdp);
 706 out_trans_fail:
 707         if (alloc_required) {
 708                 gfs2_inplace_release(ip);
 709 out_qunlock:
 710                 gfs2_quota_unlock(ip);
 711 out_alloc_put:
 712                 gfs2_alloc_put(ip);
 713         }
 714 out_unlock:
 715         gfs2_glock_dq(&ip->i_gh);
 716 out_uninit:
 717         gfs2_holder_uninit(&ip->i_gh);
 718         return error;
 719 }
 720
 721 /**
 722  * adjust_fs_space - Adjusts the free space available due to gfs2_grow
 723  * @inode: the rindex inode
 724  */
 725 static void adjust_fs_space(struct inode *inode)
 726 {
 727         struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
 728         struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
 729         struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
 730         u64 fs_total, new_free;
 731
 732         /* Total up the file system space, according to the latest rindex. */
 733         fs_total = gfs2_ri_total(sdp);
 734
 735         spin_lock(&sdp->sd_statfs_spin);
 736         if (fs_total > (m_sc->sc_total + l_sc->sc_total))
 737                 new_free = fs_total - (m_sc->sc_total + l_sc->sc_total);
 738         else
 739                 new_free = 0;
 740         spin_unlock(&sdp->sd_statfs_spin);
 741         fs_warn(sdp, "File system extended by %llu blocks.\n",
 742                 (unsigned long long)new_free);
 743         gfs2_statfs_change(sdp, new_free, new_free, 0);
 744 }
 745
 746 /**
 747  * gfs2_stuffed_write_end - Write end for stuffed files
 748  * @inode: The inode
 749  * @dibh: The buffer_head containing the on-disk inode
 750  * @pos: The file position
 751  * @len: The length of the write
 752  * @copied: How much was actually copied by the VFS
 753  * @page: The page
 754  *
 755  * This copies the data from the page into the inode block after
 756  * the inode data structure itself.
 757  *
 758  * Returns: errno
 759  */
 760 static int gfs2_stuffed_write_end(struct inode *inode, struct buffer_head *dibh,
 761                                   loff_t pos, unsigned len, unsigned copied,
 762                                   struct page *page)
 763 {
 764         struct gfs2_inode *ip = GFS2_I(inode);
 765         struct gfs2_sbd *sdp = GFS2_SB(inode);
 766         u64 to = pos + copied;
 767         void *kaddr;
 768         unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode);
 769         struct gfs2_dinode *di = (struct gfs2_dinode *)dibh->b_data;
 770
 771         BUG_ON((pos + len) > (dibh->b_size - sizeof(struct gfs2_dinode)));
 772         kaddr = kmap_atomic(page, KM_USER0);
 773         memcpy(buf + pos, kaddr + pos, copied);
 774         memset(kaddr + pos + copied, 0, len - copied);
 775         flush_dcache_page(page);
 776         kunmap_atomic(kaddr, KM_USER0);
 777
 778         if (!PageUptodate(page))
 779                 SetPageUptodate(page);
 780         unlock_page(page);
 781         page_cache_release(page);
 782
 783         if (inode->i_size < to) {
 784                 i_size_write(inode, to);
 785                 ip->i_di.di_size = inode->i_size;
 786                 di->di_size = cpu_to_be64(inode->i_size);
 787                 mark_inode_dirty(inode);
 788         }
 789
 790         if (inode == sdp->sd_rindex)
 791                 adjust_fs_space(inode);
 792
 793         brelse(dibh);
 794         gfs2_trans_end(sdp);
 795         gfs2_glock_dq(&ip->i_gh);
 796         gfs2_holder_uninit(&ip->i_gh);
 797         return copied;
 798 }
 799
 800 /**
 801  * gfs2_write_end
 802  * @file: The file to write to
 803  * @mapping: The address space to write to
 804  * @pos: The file position
 805  * @len: The length of the data
 806  * @copied:
 807  * @page: The page that has been written
 808  * @fsdata: The fsdata (unused in GFS2)
 809  *
 810  * The main write_end function for GFS2. We have a separate one for
 811  * stuffed files as they are slightly different, otherwise we just
 812  * put our locking around the VFS provided functions.
 813  *
 814  * Returns: errno
 815  */
 816
 817 static int gfs2_write_end(struct file *file, struct address_space *mapping,
 818                           loff_t pos, unsigned len, unsigned copied,
 819                           struct page *page, void *fsdata)
 820 {
 821         struct inode *inode = page->mapping->host;
 822         struct gfs2_inode *ip = GFS2_I(inode);
 823         struct gfs2_sbd *sdp = GFS2_SB(inode);
 824         struct buffer_head *dibh;
 825         struct gfs2_alloc *al = ip->i_alloc;
 826         struct gfs2_dinode *di;
 827         unsigned int from = pos & (PAGE_CACHE_SIZE - 1);
 828         unsigned int to = from + len;
 829         int ret;
 830
 831         BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL);
 832
 833         ret = gfs2_meta_inode_buffer(ip, &dibh);
 834         if (unlikely(ret)) {
 835                 unlock_page(page);
 836                 page_cache_release(page);
 837                 goto failed;
 838         }
 839
 840         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 841
 842         if (gfs2_is_stuffed(ip))
 843                 return gfs2_stuffed_write_end(inode, dibh, pos, len, copied, page);
 844
 845         if (!gfs2_is_writeback(ip))
 846                 gfs2_page_add_databufs(ip, page, from, to);
 847
 848         ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
 849
 850         if (likely(ret >= 0) && (inode->i_size > ip->i_di.di_size)) {
 851                 di = (struct gfs2_dinode *)dibh->b_data;
 852                 ip->i_di.di_size = inode->i_size;
 853                 di->di_size = cpu_to_be64(inode->i_size);
 854                 mark_inode_dirty(inode);
 855         }
 856
 857         if (inode == sdp->sd_rindex)
 858                 adjust_fs_space(inode);
 859
 860         brelse(dibh);
 861         gfs2_trans_end(sdp);
 862 failed:
 863         if (al) {
 864                 gfs2_inplace_release(ip);
 865                 gfs2_quota_unlock(ip);
 866                 gfs2_alloc_put(ip);
 867         }
 868         gfs2_glock_dq(&ip->i_gh);
 869         gfs2_holder_uninit(&ip->i_gh);
 870         return ret;
 871 }
 872
 873 /**
 874  * gfs2_set_page_dirty - Page dirtying function
 875  * @page: The page to dirty
 876  *
 877  * Returns: 1 if it dirtyed the page, or 0 otherwise
 878  */
 879
 880 static int gfs2_set_page_dirty(struct page *page)
 881 {
 882         SetPageChecked(page);
 883         return __set_page_dirty_buffers(page);
 884 }
 885
 886 /**
 887  * gfs2_bmap - Block map function
 888  * @mapping: Address space info
 889  * @lblock: The block to map
 890  *
 891  * Returns: The disk address for the block or 0 on hole or error
 892  */
 893
 894 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 895 {
 896         struct gfs2_inode *ip = GFS2_I(mapping->host);
 897         struct gfs2_holder i_gh;
 898         sector_t dblock = 0;
 899         int error;
 900
 901         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 902         if (error)
 903                 return 0;
 904
 905         if (!gfs2_is_stuffed(ip))
 906                 dblock = generic_block_bmap(mapping, lblock, gfs2_block_map);
 907
 908         gfs2_glock_dq_uninit(&i_gh);
 909
 910         return dblock;
 911 }
 912
 913 static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
 914 {
 915         struct gfs2_bufdata *bd;
 916
 917         lock_buffer(bh);
 918         gfs2_log_lock(sdp);
 919         clear_buffer_dirty(bh);
 920         bd = bh->b_private;
 921         if (bd) {
 922                 if (!list_empty(&bd->bd_le.le_list) && !buffer_pinned(bh))
 923                         list_del_init(&bd->bd_le.le_list);
 924                 else
 925                         gfs2_remove_from_journal(bh, current->journal_info, 0);
 926         }
 927         bh->b_bdev = NULL;
 928         clear_buffer_mapped(bh);
 929         clear_buffer_req(bh);
 930         clear_buffer_new(bh);
 931         gfs2_log_unlock(sdp);
 932         unlock_buffer(bh);
 933 }
 934
 935 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 936 {
 937         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 938         struct buffer_head *bh, *head;
 939         unsigned long pos = 0;
 940
 941         BUG_ON(!PageLocked(page));
 942         if (offset == 0)
 943                 ClearPageChecked(page);
 944         if (!page_has_buffers(page))
 945                 goto out;
 946
 947         bh = head = page_buffers(page);
 948         do {
 949                 if (offset <= pos)
 950                         gfs2_discard(sdp, bh);
 951                 pos += bh->b_size;
 952                 bh = bh->b_this_page;
 953         } while (bh != head);
 954 out:
 955         if (offset == 0)
 956                 try_to_release_page(page, 0);
 957 }
 958
 959 /**
 960  * gfs2_ok_for_dio - check that dio is valid on this file
 961  * @ip: The inode
 962  * @rw: READ or WRITE
 963  * @offset: The offset at which we are reading or writing
 964  *
 965  * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
 966  *          1 (to accept the i/o request)
 967  */
 968 static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
 969 {
 970         /*
 971          * Should we return an error here? I can't see that O_DIRECT for
 972          * a stuffed file makes any sense. For now we'll silently fall
 973          * back to buffered I/O
 974          */
 975         if (gfs2_is_stuffed(ip))
 976                 return 0;
 977
 978         if (offset > i_size_read(&ip->i_inode))
 979                 return 0;
 980         return 1;
 981 }
 982
 983
 984
 985 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 986                               const struct iovec *iov, loff_t offset,
 987                               unsigned long nr_segs)
 988 {
 989         struct file *file = iocb->ki_filp;
 990         struct inode *inode = file->f_mapping->host;
 991         struct gfs2_inode *ip = GFS2_I(inode);
 992         struct gfs2_holder gh;
 993         int rv;
 994
 995         /*
 996          * Deferred lock, even if its a write, since we do no allocation
 997          * on this path. All we need change is atime, and this lock mode
 998          * ensures that other nodes have flushed their buffered read caches
 999          * (i.e. their page cache entries for this inode). We do not,
1000          * unfortunately have the option of only flushing a range like
1001          * the VFS does.
1002          */
1003         gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, GL_ATIME, &gh);
1004         rv = gfs2_glock_nq_atime(&gh);
1005         if (rv)
1006                 return rv;
1007         rv = gfs2_ok_for_dio(ip, rw, offset);
1008         if (rv != 1)
1009                 goto out; /* dio not valid, fall back to buffered i/o */
1010
1011         rv = blockdev_direct_IO_no_locking(rw, iocb, inode, inode->i_sb->s_bdev,
1012                                            iov, offset, nr_segs,
1013                                            gfs2_get_block_direct, NULL);
1014 out:
1015         gfs2_glock_dq_m(1, &gh);
1016         gfs2_holder_uninit(&gh);
1017         return rv;
1018 }
1019
1020 /**
1021  * gfs2_releasepage - free the metadata associated with a page
1022  * @page: the page that's being released
1023  * @gfp_mask: passed from Linux VFS, ignored by us
1024  *
1025  * Call try_to_free_buffers() if the buffers in this page can be
1026  * released.
1027  *
1028  * Returns: 0
1029  */
1030
1031 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
1032 {
1033         struct inode *aspace = page->mapping->host;
1034         struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
1035         struct buffer_head *bh, *head;
1036         struct gfs2_bufdata *bd;
1037
1038         if (!page_has_buffers(page))
1039                 return 0;
1040
1041         gfs2_log_lock(sdp);
1042         head = bh = page_buffers(page);
1043         do {
1044                 if (atomic_read(&bh->b_count))
1045                         goto cannot_release;
1046                 bd = bh->b_private;
1047                 if (bd && bd->bd_ail)
1048                         goto cannot_release;
1049                 gfs2_assert_warn(sdp, !buffer_pinned(bh));
1050                 gfs2_assert_warn(sdp, !buffer_dirty(bh));
1051                 bh = bh->b_this_page;
1052         } while(bh != head);
1053         gfs2_log_unlock(sdp);
1054
1055         head = bh = page_buffers(page);
1056         do {
1057                 gfs2_log_lock(sdp);
1058                 bd = bh->b_private;
1059                 if (bd) {
1060                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
1061                         gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
1062                         if (!list_empty(&bd->bd_le.le_list)) {
1063                                 if (!buffer_pinned(bh))
1064                                         list_del_init(&bd->bd_le.le_list);
1065                                 else
1066                                         bd = NULL;
1067                         }
1068                         if (bd)
1069                                 bd->bd_bh = NULL;
1070                         bh->b_private = NULL;
1071                 }
1072                 gfs2_log_unlock(sdp);
1073                 if (bd)
1074                         kmem_cache_free(gfs2_bufdata_cachep, bd);
1075
1076                 bh = bh->b_this_page;
1077         } while (bh != head);
1078
1079         return try_to_free_buffers(page);
1080 cannot_release:
1081         gfs2_log_unlock(sdp);
1082         return 0;
1083 }
1084
1085 static const struct address_space_operations gfs2_writeback_aops = {
1086         .writepage = gfs2_writeback_writepage,
1087         .writepages = gfs2_writeback_writepages,
1088         .readpage = gfs2_readpage,
1089         .readpages = gfs2_readpages,
1090         .sync_page = block_sync_page,
1091         .write_begin = gfs2_write_begin,
1092         .write_end = gfs2_write_end,
1093         .bmap = gfs2_bmap,
1094         .invalidatepage = gfs2_invalidatepage,
1095         .releasepage = gfs2_releasepage,
1096         .direct_IO = gfs2_direct_IO,
1097         .migratepage = buffer_migrate_page,
1098 };
1099
1100 static const struct address_space_operations gfs2_ordered_aops = {
1101         .writepage = gfs2_ordered_writepage,
1102         .readpage = gfs2_readpage,
1103         .readpages = gfs2_readpages,
1104         .sync_page = block_sync_page,
1105         .write_begin = gfs2_write_begin,
1106         .write_end = gfs2_write_end,
1107         .set_page_dirty = gfs2_set_page_dirty,
1108         .bmap = gfs2_bmap,
1109         .invalidatepage = gfs2_invalidatepage,
1110         .releasepage = gfs2_releasepage,
1111         .direct_IO = gfs2_direct_IO,
1112         .migratepage = buffer_migrate_page,
1113 };
1114
1115 static const struct address_space_operations gfs2_jdata_aops = {
1116         .writepage = gfs2_jdata_writepage,
1117         .writepages = gfs2_jdata_writepages,
1118         .readpage = gfs2_readpage,
1119         .readpages = gfs2_readpages,
1120         .sync_page = block_sync_page,
1121         .write_begin = gfs2_write_begin,
1122         .write_end = gfs2_write_end,
1123         .set_page_dirty = gfs2_set_page_dirty,
1124         .bmap = gfs2_bmap,
1125         .invalidatepage = gfs2_invalidatepage,
1126         .releasepage = gfs2_releasepage,
1127 };
1128
1129 void gfs2_set_aops(struct inode *inode)
1130 {
1131         struct gfs2_inode *ip = GFS2_I(inode);
1132
1133         if (gfs2_is_writeback(ip))
1134                 inode->i_mapping->a_ops = &gfs2_writeback_aops;
1135         else if (gfs2_is_ordered(ip))
1136                 inode->i_mapping->a_ops = &gfs2_ordered_aops;
1137         else if (gfs2_is_jdata(ip))
1138                 inode->i_mapping->a_ops = &gfs2_jdata_aops;
1139         else
1140                 BUG();
1141 }
1142