fs/gfs2/aops.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/backing-dev.h>
  23
  24 #include "gfs2.h"
  25 #include "incore.h"
  26 #include "bmap.h"
  27 #include "glock.h"
  28 #include "inode.h"
  29 #include "log.h"
  30 #include "meta_io.h"
  31 #include "quota.h"
  32 #include "trans.h"
  33 #include "rgrp.h"
  34 #include "super.h"
  35 #include "util.h"
  36 #include "glops.h"
  37
  38
  39 static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
  40                                    unsigned int from, unsigned int to)
  41 {
  42         struct buffer_head *head = page_buffers(page);
  43         unsigned int bsize = head->b_size;
  44         struct buffer_head *bh;
  45         unsigned int start, end;
  46
  47         for (bh = head, start = 0; bh != head || !start;
  48              bh = bh->b_this_page, start = end) {
  49                 end = start + bsize;
  50                 if (end <= from || start >= to)
  51                         continue;
  52                 if (gfs2_is_jdata(ip))
  53                         set_buffer_uptodate(bh);
  54                 gfs2_trans_add_bh(ip->i_gl, bh, 0);
  55         }
  56 }
  57
  58 /**
  59  * gfs2_get_block_noalloc - Fills in a buffer head with details about a block
  60  * @inode: The inode
  61  * @lblock: The block number to look up
  62  * @bh_result: The buffer head to return the result in
  63  * @create: Non-zero if we may add block to the file
  64  *
  65  * Returns: errno
  66  */
  67
  68 static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
  69                                   struct buffer_head *bh_result, int create)
  70 {
  71         int error;
  72
  73         error = gfs2_block_map(inode, lblock, bh_result, 0);
  74         if (error)
  75                 return error;
  76         if (!buffer_mapped(bh_result))
  77                 return -EIO;
  78         return 0;
  79 }
  80
  81 static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
  82                                  struct buffer_head *bh_result, int create)
  83 {
  84         return gfs2_block_map(inode, lblock, bh_result, 0);
  85 }
  86
  87 /**
  88  * gfs2_writepage_common - Common bits of writepage
  89  * @page: The page to be written
  90  * @wbc: The writeback control
  91  *
  92  * Returns: 1 if writepage is ok, otherwise an error code or zero if no error.
  93  */
  94
  95 static int gfs2_writepage_common(struct page *page,
  96                                  struct writeback_control *wbc)
  97 {
  98         struct inode *inode = page->mapping->host;
  99         struct gfs2_inode *ip = GFS2_I(inode);
 100         struct gfs2_sbd *sdp = GFS2_SB(inode);
 101         loff_t i_size = i_size_read(inode);
 102         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 103         unsigned offset;
 104
 105         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
 106                 goto out;
 107         if (current->journal_info)
 108                 goto redirty;
 109         /* Is the page fully outside i_size? (truncate in progress) */
 110         offset = i_size & (PAGE_CACHE_SIZE-1);
 111         if (page->index > end_index || (page->index == end_index && !offset)) {
 112                 page->mapping->a_ops->invalidatepage(page, 0);
 113                 goto out;
 114         }
 115         return 1;
 116 redirty:
 117         redirty_page_for_writepage(wbc, page);
 118 out:
 119         unlock_page(page);
 120         return 0;
 121 }
 122
 123 /**
 124  * gfs2_writeback_writepage - Write page for writeback mappings
 125  * @page: The page
 126  * @wbc: The writeback control
 127  *
 128  */
 129
 130 static int gfs2_writeback_writepage(struct page *page,
 131                                     struct writeback_control *wbc)
 132 {
 133         int ret;
 134
 135         ret = gfs2_writepage_common(page, wbc);
 136         if (ret <= 0)
 137                 return ret;
 138
 139         ret = mpage_writepage(page, gfs2_get_block_noalloc, wbc);
 140         if (ret == -EAGAIN)
 141                 ret = block_write_full_page(page, gfs2_get_block_noalloc, wbc);
 142         return ret;
 143 }
 144
 145 /**
 146  * gfs2_ordered_writepage - Write page for ordered data files
 147  * @page: The page to write
 148  * @wbc: The writeback control
 149  *
 150  */
 151
 152 static int gfs2_ordered_writepage(struct page *page,
 153                                   struct writeback_control *wbc)
 154 {
 155         struct inode *inode = page->mapping->host;
 156         struct gfs2_inode *ip = GFS2_I(inode);
 157         int ret;
 158
 159         ret = gfs2_writepage_common(page, wbc);
 160         if (ret <= 0)
 161                 return ret;
 162
 163         if (!page_has_buffers(page)) {
 164                 create_empty_buffers(page, inode->i_sb->s_blocksize,
 165                                      (1 << BH_Dirty)|(1 << BH_Uptodate));
 166         }
 167         gfs2_page_add_databufs(ip, page, 0, inode->i_sb->s_blocksize-1);
 168         return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
 169 }
 170
 171 /**
 172  * __gfs2_jdata_writepage - The core of jdata writepage
 173  * @page: The page to write
 174  * @wbc: The writeback control
 175  *
 176  * This is shared between writepage and writepages and implements the
 177  * core of the writepage operation. If a transaction is required then
 178  * PageChecked will have been set and the transaction will have
 179  * already been started before this is called.
 180  */
 181
 182 static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
 183 {
 184         struct inode *inode = page->mapping->host;
 185         struct gfs2_inode *ip = GFS2_I(inode);
 186         struct gfs2_sbd *sdp = GFS2_SB(inode);
 187
 188         if (PageChecked(page)) {
 189                 ClearPageChecked(page);
 190                 if (!page_has_buffers(page)) {
 191                         create_empty_buffers(page, inode->i_sb->s_blocksize,
 192                                              (1 << BH_Dirty)|(1 << BH_Uptodate));
 193                 }
 194                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
 195         }
 196         return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
 197 }
 198
 199 /**
 200  * gfs2_jdata_writepage - Write complete page
 201  * @page: Page to write
 202  *
 203  * Returns: errno
 204  *
 205  */
 206
 207 static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
 208 {
 209         struct inode *inode = page->mapping->host;
 210         struct gfs2_sbd *sdp = GFS2_SB(inode);
 211         int ret;
 212         int done_trans = 0;
 213
 214         if (PageChecked(page)) {
 215                 if (wbc->sync_mode != WB_SYNC_ALL)
 216                         goto out_ignore;
 217                 ret = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 218                 if (ret)
 219                         goto out_ignore;
 220                 done_trans = 1;
 221         }
 222         ret = gfs2_writepage_common(page, wbc);
 223         if (ret > 0)
 224                 ret = __gfs2_jdata_writepage(page, wbc);
 225         if (done_trans)
 226                 gfs2_trans_end(sdp);
 227         return ret;
 228
 229 out_ignore:
 230         redirty_page_for_writepage(wbc, page);
 231         unlock_page(page);
 232         return 0;
 233 }
 234
 235 /**
 236  * gfs2_writeback_writepages - Write a bunch of dirty pages back to disk
 237  * @mapping: The mapping to write
 238  * @wbc: Write-back control
 239  *
 240  * For the data=writeback case we can already ignore buffer heads
 241  * and write whole extents at once. This is a big reduction in the
 242  * number of I/O requests we send and the bmap calls we make in this case.
 243  */
 244 static int gfs2_writeback_writepages(struct address_space *mapping,
 245                                      struct writeback_control *wbc)
 246 {
 247         return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
 248 }
 249
 250 /**
 251  * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
 252  * @mapping: The mapping
 253  * @wbc: The writeback control
 254  * @writepage: The writepage function to call for each page
 255  * @pvec: The vector of pages
 256  * @nr_pages: The number of pages to write
 257  *
 258  * Returns: non-zero if loop should terminate, zero otherwise
 259  */
 260
 261 static int gfs2_write_jdata_pagevec(struct address_space *mapping,
 262                                     struct writeback_control *wbc,
 263                                     struct pagevec *pvec,
 264                                     int nr_pages, pgoff_t end)
 265 {
 266         struct inode *inode = mapping->host;
 267         struct gfs2_sbd *sdp = GFS2_SB(inode);
 268         loff_t i_size = i_size_read(inode);
 269         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 270         unsigned offset = i_size & (PAGE_CACHE_SIZE-1);
 271         unsigned nrblocks = nr_pages * (PAGE_CACHE_SIZE/inode->i_sb->s_blocksize);
 272         struct backing_dev_info *bdi = mapping->backing_dev_info;
 273         int i;
 274         int ret;
 275
 276         ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
 277         if (ret < 0)
 278                 return ret;
 279
 280         for(i = 0; i < nr_pages; i++) {
 281                 struct page *page = pvec->pages[i];
 282
 283                 lock_page(page);
 284
 285                 if (unlikely(page->mapping != mapping)) {
 286                         unlock_page(page);
 287                         continue;
 288                 }
 289
 290                 if (!wbc->range_cyclic && page->index > end) {
 291                         ret = 1;
 292                         unlock_page(page);
 293                         continue;
 294                 }
 295
 296                 if (wbc->sync_mode != WB_SYNC_NONE)
 297                         wait_on_page_writeback(page);
 298
 299                 if (PageWriteback(page) ||
 300                     !clear_page_dirty_for_io(page)) {
 301                         unlock_page(page);
 302                         continue;
 303                 }
 304
 305                 /* Is the page fully outside i_size? (truncate in progress) */
 306                 if (page->index > end_index || (page->index == end_index && !offset)) {
 307                         page->mapping->a_ops->invalidatepage(page, 0);
 308                         unlock_page(page);
 309                         continue;
 310                 }
 311
 312                 ret = __gfs2_jdata_writepage(page, wbc);
 313
 314                 if (ret || (--(wbc->nr_to_write) <= 0))
 315                         ret = 1;
 316                 if (wbc->nonblocking && bdi_write_congested(bdi)) {
 317                         wbc->encountered_congestion = 1;
 318                         ret = 1;
 319                 }
 320
 321         }
 322         gfs2_trans_end(sdp);
 323         return ret;
 324 }
 325
 326 /**
 327  * gfs2_write_cache_jdata - Like write_cache_pages but different
 328  * @mapping: The mapping to write
 329  * @wbc: The writeback control
 330  * @writepage: The writepage function to call
 331  * @data: The data to pass to writepage
 332  *
 333  * The reason that we use our own function here is that we need to
 334  * start transactions before we grab page locks. This allows us
 335  * to get the ordering right.
 336  */
 337
 338 static int gfs2_write_cache_jdata(struct address_space *mapping,
 339                                   struct writeback_control *wbc)
 340 {
 341         struct backing_dev_info *bdi = mapping->backing_dev_info;
 342         int ret = 0;
 343         int done = 0;
 344         struct pagevec pvec;
 345         int nr_pages;
 346         pgoff_t index;
 347         pgoff_t end;
 348         int scanned = 0;
 349         int range_whole = 0;
 350
 351         if (wbc->nonblocking && bdi_write_congested(bdi)) {
 352                 wbc->encountered_congestion = 1;
 353                 return 0;
 354         }
 355
 356         pagevec_init(&pvec, 0);
 357         if (wbc->range_cyclic) {
 358                 index = mapping->writeback_index; /* Start from prev offset */
 359                 end = -1;
 360         } else {
 361                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
 362                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
 363                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
 364                         range_whole = 1;
 365                 scanned = 1;
 366         }
 367
 368 retry:
 369          while (!done && (index <= end) &&
 370                 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
 371                                                PAGECACHE_TAG_DIRTY,
 372                                                min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
 373                 scanned = 1;
 374                 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, end);
 375                 if (ret)
 376                         done = 1;
 377                 if (ret > 0)
 378                         ret = 0;
 379
 380                 pagevec_release(&pvec);
 381                 cond_resched();
 382         }
 383
 384         if (!scanned && !done) {
 385                 /*
 386                  * We hit the last page and there is more work to be done: wrap
 387                  * back to the start of the file
 388                  */
 389                 scanned = 1;
 390                 index = 0;
 391                 goto retry;
 392         }
 393
 394         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 395                 mapping->writeback_index = index;
 396         return ret;
 397 }
 398
 399
 400 /**
 401  * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
 402  * @mapping: The mapping to write
 403  * @wbc: The writeback control
 404  *
 405  */
 406
 407 static int gfs2_jdata_writepages(struct address_space *mapping,
 408                                  struct writeback_control *wbc)
 409 {
 410         struct gfs2_inode *ip = GFS2_I(mapping->host);
 411         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
 412         int ret;
 413
 414         ret = gfs2_write_cache_jdata(mapping, wbc);
 415         if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
 416                 gfs2_log_flush(sdp, ip->i_gl);
 417                 ret = gfs2_write_cache_jdata(mapping, wbc);
 418         }
 419         return ret;
 420 }
 421
 422 /**
 423  * stuffed_readpage - Fill in a Linux page with stuffed file data
 424  * @ip: the inode
 425  * @page: the page
 426  *
 427  * Returns: errno
 428  */
 429
 430 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 431 {
 432         struct buffer_head *dibh;
 433         void *kaddr;
 434         int error;
 435
 436         /*
 437          * Due to the order of unstuffing files and ->fault(), we can be
 438          * asked for a zero page in the case of a stuffed file being extended,
 439          * so we need to supply one here. It doesn't happen often.
 440          */
 441         if (unlikely(page->index)) {
 442                 zero_user(page, 0, PAGE_CACHE_SIZE);
 443                 SetPageUptodate(page);
 444                 return 0;
 445         }
 446
 447         error = gfs2_meta_inode_buffer(ip, &dibh);
 448         if (error)
 449                 return error;
 450
 451         kaddr = kmap_atomic(page, KM_USER0);
 452         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
 453                ip->i_disksize);
 454         memset(kaddr + ip->i_disksize, 0, PAGE_CACHE_SIZE - ip->i_disksize);
 455         kunmap_atomic(kaddr, KM_USER0);
 456         flush_dcache_page(page);
 457         brelse(dibh);
 458         SetPageUptodate(page);
 459
 460         return 0;
 461 }
 462
 463
 464 /**
 465  * __gfs2_readpage - readpage
 466  * @file: The file to read a page for
 467  * @page: The page to read
 468  *
 469  * This is the core of gfs2's readpage. Its used by the internal file
 470  * reading code as in that case we already hold the glock. Also its
 471  * called by gfs2_readpage() once the required lock has been granted.
 472  *
 473  */
 474
 475 static int __gfs2_readpage(void *file, struct page *page)
 476 {
 477         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 478         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 479         int error;
 480
 481         if (gfs2_is_stuffed(ip)) {
 482                 error = stuffed_readpage(ip, page);
 483                 unlock_page(page);
 484         } else {
 485                 error = mpage_readpage(page, gfs2_block_map);
 486         }
 487
 488         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 489                 return -EIO;
 490
 491         return error;
 492 }
 493
 494 /**
 495  * gfs2_readpage - read a page of a file
 496  * @file: The file to read
 497  * @page: The page of the file
 498  *
 499  * This deals with the locking required. We have to unlock and
 500  * relock the page in order to get the locking in the right
 501  * order.
 502  */
 503
 504 static int gfs2_readpage(struct file *file, struct page *page)
 505 {
 506         struct address_space *mapping = page->mapping;
 507         struct gfs2_inode *ip = GFS2_I(mapping->host);
 508         struct gfs2_holder gh;
 509         int error;
 510
 511         unlock_page(page);
 512         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
 513         error = gfs2_glock_nq(&gh);
 514         if (unlikely(error))
 515                 goto out;
 516         error = AOP_TRUNCATED_PAGE;
 517         lock_page(page);
 518         if (page->mapping == mapping && !PageUptodate(page))
 519                 error = __gfs2_readpage(file, page);
 520         else
 521                 unlock_page(page);
 522         gfs2_glock_dq(&gh);
 523 out:
 524         gfs2_holder_uninit(&gh);
 525         if (error && error != AOP_TRUNCATED_PAGE)
 526                 lock_page(page);
 527         return error;
 528 }
 529
 530 /**
 531  * gfs2_internal_read - read an internal file
 532  * @ip: The gfs2 inode
 533  * @ra_state: The readahead state (or NULL for no readahead)
 534  * @buf: The buffer to fill
 535  * @pos: The file position
 536  * @size: The amount to read
 537  *
 538  */
 539
 540 int gfs2_internal_read(struct gfs2_inode *ip, struct file_ra_state *ra_state,
 541                        char *buf, loff_t *pos, unsigned size)
 542 {
 543         struct address_space *mapping = ip->i_inode.i_mapping;
 544         unsigned long index = *pos / PAGE_CACHE_SIZE;
 545         unsigned offset = *pos & (PAGE_CACHE_SIZE - 1);
 546         unsigned copied = 0;
 547         unsigned amt;
 548         struct page *page;
 549         void *p;
 550
 551         do {
 552                 amt = size - copied;
 553                 if (offset + size > PAGE_CACHE_SIZE)
 554                         amt = PAGE_CACHE_SIZE - offset;
 555                 page = read_cache_page(mapping, index, __gfs2_readpage, NULL);
 556                 if (IS_ERR(page))
 557                         return PTR_ERR(page);
 558                 p = kmap_atomic(page, KM_USER0);
 559                 memcpy(buf + copied, p + offset, amt);
 560                 kunmap_atomic(p, KM_USER0);
 561                 mark_page_accessed(page);
 562                 page_cache_release(page);
 563                 copied += amt;
 564                 index++;
 565                 offset = 0;
 566         } while(copied < size);
 567         (*pos) += size;
 568         return size;
 569 }
 570
 571 /**
 572  * gfs2_readpages - Read a bunch of pages at once
 573  *
 574  * Some notes:
 575  * 1. This is only for readahead, so we can simply ignore any things
 576  *    which are slightly inconvenient (such as locking conflicts between
 577  *    the page lock and the glock) and return having done no I/O. Its
 578  *    obviously not something we'd want to do on too regular a basis.
 579  *    Any I/O we ignore at this time will be done via readpage later.
 580  * 2. We don't handle stuffed files here we let readpage do the honours.
 581  * 3. mpage_readpages() does most of the heavy lifting in the common case.
 582  * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
 583  */
 584
 585 static int gfs2_readpages(struct file *file, struct address_space *mapping,
 586                           struct list_head *pages, unsigned nr_pages)
 587 {
 588         struct inode *inode = mapping->host;
 589         struct gfs2_inode *ip = GFS2_I(inode);
 590         struct gfs2_sbd *sdp = GFS2_SB(inode);
 591         struct gfs2_holder gh;
 592         int ret;
 593
 594         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
 595         ret = gfs2_glock_nq(&gh);
 596         if (unlikely(ret))
 597                 goto out_uninit;
 598         if (!gfs2_is_stuffed(ip))
 599                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
 600         gfs2_glock_dq(&gh);
 601 out_uninit:
 602         gfs2_holder_uninit(&gh);
 603         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 604                 ret = -EIO;
 605         return ret;
 606 }
 607
 608 /**
 609  * gfs2_write_begin - Begin to write to a file
 610  * @file: The file to write to
 611  * @mapping: The mapping in which to write
 612  * @pos: The file offset at which to start writing
 613  * @len: Length of the write
 614  * @flags: Various flags
 615  * @pagep: Pointer to return the page
 616  * @fsdata: Pointer to return fs data (unused by GFS2)
 617  *
 618  * Returns: errno
 619  */
 620
 621 static int gfs2_write_begin(struct file *file, struct address_space *mapping,
 622                             loff_t pos, unsigned len, unsigned flags,
 623                             struct page **pagep, void **fsdata)
 624 {
 625         struct gfs2_inode *ip = GFS2_I(mapping->host);
 626         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
 627         unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
 628         int alloc_required;
 629         int error = 0;
 630         struct gfs2_alloc *al;
 631         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 632         unsigned from = pos & (PAGE_CACHE_SIZE - 1);
 633         unsigned to = from + len;
 634         struct page *page;
 635
 636         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
 637         error = gfs2_glock_nq(&ip->i_gh);
 638         if (unlikely(error))
 639                 goto out_uninit;
 640
 641         error = gfs2_write_alloc_required(ip, pos, len, &alloc_required);
 642         if (error)
 643                 goto out_unlock;
 644
 645         if (alloc_required || gfs2_is_jdata(ip))
 646                 gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
 647
 648         if (alloc_required) {
 649                 al = gfs2_alloc_get(ip);
 650                 if (!al) {
 651                         error = -ENOMEM;
 652                         goto out_unlock;
 653                 }
 654
 655                 error = gfs2_quota_lock_check(ip);
 656                 if (error)
 657                         goto out_alloc_put;
 658
 659                 al->al_requested = data_blocks + ind_blocks;
 660                 error = gfs2_inplace_reserve(ip);
 661                 if (error)
 662                         goto out_qunlock;
 663         }
 664
 665         rblocks = RES_DINODE + ind_blocks;
 666         if (gfs2_is_jdata(ip))
 667                 rblocks += data_blocks ? data_blocks : 1;
 668         if (ind_blocks || data_blocks)
 669                 rblocks += RES_STATFS + RES_QUOTA;
 670
 671         error = gfs2_trans_begin(sdp, rblocks,
 672                                  PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize);
 673         if (error)
 674                 goto out_trans_fail;
 675
 676         error = -ENOMEM;
 677         flags |= AOP_FLAG_NOFS;
 678         page = grab_cache_page_write_begin(mapping, index, flags);
 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 (copied) {
 784                 if (inode->i_size < to) {
 785                         i_size_write(inode, to);
 786                         ip->i_disksize = inode->i_size;
 787                 }
 788                 gfs2_dinode_out(ip, di);
 789                 mark_inode_dirty(inode);
 790         }
 791
 792         if (inode == sdp->sd_rindex)
 793                 adjust_fs_space(inode);
 794
 795         brelse(dibh);
 796         gfs2_trans_end(sdp);
 797         gfs2_glock_dq(&ip->i_gh);
 798         gfs2_holder_uninit(&ip->i_gh);
 799         return copied;
 800 }
 801
 802 /**
 803  * gfs2_write_end
 804  * @file: The file to write to
 805  * @mapping: The address space to write to
 806  * @pos: The file position
 807  * @len: The length of the data
 808  * @copied:
 809  * @page: The page that has been written
 810  * @fsdata: The fsdata (unused in GFS2)
 811  *
 812  * The main write_end function for GFS2. We have a separate one for
 813  * stuffed files as they are slightly different, otherwise we just
 814  * put our locking around the VFS provided functions.
 815  *
 816  * Returns: errno
 817  */
 818
 819 static int gfs2_write_end(struct file *file, struct address_space *mapping,
 820                           loff_t pos, unsigned len, unsigned copied,
 821                           struct page *page, void *fsdata)
 822 {
 823         struct inode *inode = page->mapping->host;
 824         struct gfs2_inode *ip = GFS2_I(inode);
 825         struct gfs2_sbd *sdp = GFS2_SB(inode);
 826         struct buffer_head *dibh;
 827         struct gfs2_alloc *al = ip->i_alloc;
 828         unsigned int from = pos & (PAGE_CACHE_SIZE - 1);
 829         unsigned int to = from + len;
 830         int ret;
 831
 832         BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL);
 833
 834         ret = gfs2_meta_inode_buffer(ip, &dibh);
 835         if (unlikely(ret)) {
 836                 unlock_page(page);
 837                 page_cache_release(page);
 838                 goto failed;
 839         }
 840
 841         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 842
 843         if (gfs2_is_stuffed(ip))
 844                 return gfs2_stuffed_write_end(inode, dibh, pos, len, copied, page);
 845
 846         if (!gfs2_is_writeback(ip))
 847                 gfs2_page_add_databufs(ip, page, from, to);
 848
 849         ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
 850         if (ret > 0) {
 851                 if (inode->i_size > ip->i_disksize)
 852                         ip->i_disksize = inode->i_size;
 853                 gfs2_dinode_out(ip, dibh->b_data);
 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, 0, &gh);
1004         rv = gfs2_glock_nq(&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         .is_partially_uptodate = block_is_partially_uptodate,
1099 };
1100
1101 static const struct address_space_operations gfs2_ordered_aops = {
1102         .writepage = gfs2_ordered_writepage,
1103         .readpage = gfs2_readpage,
1104         .readpages = gfs2_readpages,
1105         .sync_page = block_sync_page,
1106         .write_begin = gfs2_write_begin,
1107         .write_end = gfs2_write_end,
1108         .set_page_dirty = gfs2_set_page_dirty,
1109         .bmap = gfs2_bmap,
1110         .invalidatepage = gfs2_invalidatepage,
1111         .releasepage = gfs2_releasepage,
1112         .direct_IO = gfs2_direct_IO,
1113         .migratepage = buffer_migrate_page,
1114         .is_partially_uptodate = block_is_partially_uptodate,
1115 };
1116
1117 static const struct address_space_operations gfs2_jdata_aops = {
1118         .writepage = gfs2_jdata_writepage,
1119         .writepages = gfs2_jdata_writepages,
1120         .readpage = gfs2_readpage,
1121         .readpages = gfs2_readpages,
1122         .sync_page = block_sync_page,
1123         .write_begin = gfs2_write_begin,
1124         .write_end = gfs2_write_end,
1125         .set_page_dirty = gfs2_set_page_dirty,
1126         .bmap = gfs2_bmap,
1127         .invalidatepage = gfs2_invalidatepage,
1128         .releasepage = gfs2_releasepage,
1129         .is_partially_uptodate = block_is_partially_uptodate,
1130 };
1131
1132 void gfs2_set_aops(struct inode *inode)
1133 {
1134         struct gfs2_inode *ip = GFS2_I(inode);
1135
1136         if (gfs2_is_writeback(ip))
1137                 inode->i_mapping->a_ops = &gfs2_writeback_aops;
1138         else if (gfs2_is_ordered(ip))
1139                 inode->i_mapping->a_ops = &gfs2_ordered_aops;
1140         else if (gfs2_is_jdata(ip))
1141                 inode->i_mapping->a_ops = &gfs2_jdata_aops;
1142         else
1143                 BUG();
1144 }
1145