git.oblomov.eu Git - linux-2.6/blob - fs/xfs/linux-2.6/xfs_aops.c

   1 /*
   2  * Copyright (c) 2000-2005 Silicon Graphics, Inc.  All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it would be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11  *
  12  * Further, this software is distributed without any warranty that it is
  13  * free of the rightful claim of any third person regarding infringement
  14  * or the like.  Any license provided herein, whether implied or
  15  * otherwise, applies only to this software file.  Patent licenses, if
  16  * any, provided herein do not apply to combinations of this program with
  17  * other software, or any other product whatsoever.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write the Free Software Foundation, Inc., 59
  21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22  *
  23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
  24  * Mountain View, CA  94043, or:
  25  *
  26  * http://www.sgi.com
  27  *
  28  * For further information regarding this notice, see:
  29  *
  30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  31  */
  32
  33 #include "xfs.h"
  34 #include "xfs_inum.h"
  35 #include "xfs_log.h"
  36 #include "xfs_sb.h"
  37 #include "xfs_dir.h"
  38 #include "xfs_dir2.h"
  39 #include "xfs_trans.h"
  40 #include "xfs_dmapi.h"
  41 #include "xfs_mount.h"
  42 #include "xfs_bmap_btree.h"
  43 #include "xfs_alloc_btree.h"
  44 #include "xfs_ialloc_btree.h"
  45 #include "xfs_alloc.h"
  46 #include "xfs_btree.h"
  47 #include "xfs_attr_sf.h"
  48 #include "xfs_dir_sf.h"
  49 #include "xfs_dir2_sf.h"
  50 #include "xfs_dinode.h"
  51 #include "xfs_inode.h"
  52 #include "xfs_error.h"
  53 #include "xfs_rw.h"
  54 #include "xfs_iomap.h"
  55 #include <linux/mpage.h>
  56 #include <linux/writeback.h>
  57
  58 STATIC void xfs_count_page_state(struct page *, int *, int *, int *);
  59 STATIC void xfs_convert_page(struct inode *, struct page *, xfs_iomap_t *,
  60                 struct writeback_control *wbc, void *, int, int);
  61
  62 #if defined(XFS_RW_TRACE)
  63 void
  64 xfs_page_trace(
  65         int             tag,
  66         struct inode    *inode,
  67         struct page     *page,
  68         int             mask)
  69 {
  70         xfs_inode_t     *ip;
  71         bhv_desc_t      *bdp;
  72         vnode_t         *vp = LINVFS_GET_VP(inode);
  73         loff_t          isize = i_size_read(inode);
  74         loff_t          offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
  75         int             delalloc = -1, unmapped = -1, unwritten = -1;
  76
  77         if (page_has_buffers(page))
  78                 xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
  79
  80         bdp = vn_bhv_lookup(VN_BHV_HEAD(vp), &xfs_vnodeops);
  81         ip = XFS_BHVTOI(bdp);
  82         if (!ip->i_rwtrace)
  83                 return;
  84
  85         ktrace_enter(ip->i_rwtrace,
  86                 (void *)((unsigned long)tag),
  87                 (void *)ip,
  88                 (void *)inode,
  89                 (void *)page,
  90                 (void *)((unsigned long)mask),
  91                 (void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
  92                 (void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
  93                 (void *)((unsigned long)((isize >> 32) & 0xffffffff)),
  94                 (void *)((unsigned long)(isize & 0xffffffff)),
  95                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
  96                 (void *)((unsigned long)(offset & 0xffffffff)),
  97                 (void *)((unsigned long)delalloc),
  98                 (void *)((unsigned long)unmapped),
  99                 (void *)((unsigned long)unwritten),
 100                 (void *)NULL,
 101                 (void *)NULL);
 102 }
 103 #else
 104 #define xfs_page_trace(tag, inode, page, mask)
 105 #endif
 106
 107 /*
 108  * Schedule IO completion handling on a xfsdatad if this was
 109  * the final hold on this ioend.
 110  */
 111 STATIC void
 112 xfs_finish_ioend(
 113         xfs_ioend_t             *ioend)
 114 {
 115         if (atomic_dec_and_test(&ioend->io_remaining))
 116                 queue_work(xfsdatad_workqueue, &ioend->io_work);
 117 }
 118
 119 STATIC void
 120 xfs_destroy_ioend(
 121         xfs_ioend_t             *ioend)
 122 {
 123         vn_iowake(ioend->io_vnode);
 124         mempool_free(ioend, xfs_ioend_pool);
 125 }
 126
 127 /*
 128  * Issue transactions to convert a buffer range from unwritten
 129  * to written extents.
 130  */
 131 STATIC void
 132 xfs_end_bio_unwritten(
 133         void                    *data)
 134 {
 135         xfs_ioend_t             *ioend = data;
 136         vnode_t                 *vp = ioend->io_vnode;
 137         xfs_off_t               offset = ioend->io_offset;
 138         size_t                  size = ioend->io_size;
 139         struct buffer_head      *bh, *next;
 140         int                     error;
 141
 142         if (ioend->io_uptodate)
 143                 VOP_BMAP(vp, offset, size, BMAPI_UNWRITTEN, NULL, NULL, error);
 144
 145         /* ioend->io_buffer_head is only non-NULL for buffered I/O */
 146         for (bh = ioend->io_buffer_head; bh; bh = next) {
 147                 next = bh->b_private;
 148
 149                 bh->b_end_io = NULL;
 150                 clear_buffer_unwritten(bh);
 151                 end_buffer_async_write(bh, ioend->io_uptodate);
 152         }
 153
 154         xfs_destroy_ioend(ioend);
 155 }
 156
 157 /*
 158  * Allocate and initialise an IO completion structure.
 159  * We need to track unwritten extent write completion here initially.
 160  * We'll need to extend this for updating the ondisk inode size later
 161  * (vs. incore size).
 162  */
 163 STATIC xfs_ioend_t *
 164 xfs_alloc_ioend(
 165         struct inode            *inode)
 166 {
 167         xfs_ioend_t             *ioend;
 168
 169         ioend = mempool_alloc(xfs_ioend_pool, GFP_NOFS);
 170
 171         /*
 172          * Set the count to 1 initially, which will prevent an I/O
 173          * completion callback from happening before we have started
 174          * all the I/O from calling the completion routine too early.
 175          */
 176         atomic_set(&ioend->io_remaining, 1);
 177         ioend->io_uptodate = 1; /* cleared if any I/O fails */
 178         ioend->io_vnode = LINVFS_GET_VP(inode);
 179         ioend->io_buffer_head = NULL;
 180         atomic_inc(&ioend->io_vnode->v_iocount);
 181         ioend->io_offset = 0;
 182         ioend->io_size = 0;
 183
 184         INIT_WORK(&ioend->io_work, xfs_end_bio_unwritten, ioend);
 185
 186         return ioend;
 187 }
 188
 189 void
 190 linvfs_unwritten_done(
 191         struct buffer_head      *bh,
 192         int                     uptodate)
 193 {
 194         xfs_ioend_t             *ioend = bh->b_private;
 195         static spinlock_t       unwritten_done_lock = SPIN_LOCK_UNLOCKED;
 196         unsigned long           flags;
 197
 198         ASSERT(buffer_unwritten(bh));
 199         bh->b_end_io = NULL;
 200
 201         if (!uptodate)
 202                 ioend->io_uptodate = 0;
 203
 204         /*
 205          * Deep magic here.  We reuse b_private in the buffer_heads to build
 206          * a chain for completing the I/O from user context after we've issued
 207          * a transaction to convert the unwritten extent.
 208          */
 209         spin_lock_irqsave(&unwritten_done_lock, flags);
 210         bh->b_private = ioend->io_buffer_head;
 211         ioend->io_buffer_head = bh;
 212         spin_unlock_irqrestore(&unwritten_done_lock, flags);
 213
 214         xfs_finish_ioend(ioend);
 215 }
 216
 217 STATIC int
 218 xfs_map_blocks(
 219         struct inode            *inode,
 220         loff_t                  offset,
 221         ssize_t                 count,
 222         xfs_iomap_t             *mapp,
 223         int                     flags)
 224 {
 225         vnode_t                 *vp = LINVFS_GET_VP(inode);
 226         int                     error, nmaps = 1;
 227
 228         VOP_BMAP(vp, offset, count, flags, mapp, &nmaps, error);
 229         if (!error && (flags & (BMAPI_WRITE|BMAPI_ALLOCATE)))
 230                 VMODIFY(vp);
 231         return -error;
 232 }
 233
 234 /*
 235  * Finds the corresponding mapping in block @map array of the
 236  * given @offset within a @page.
 237  */
 238 STATIC xfs_iomap_t *
 239 xfs_offset_to_map(
 240         struct page             *page,
 241         xfs_iomap_t             *iomapp,
 242         unsigned long           offset)
 243 {
 244         loff_t                  full_offset;    /* offset from start of file */
 245
 246         ASSERT(offset < PAGE_CACHE_SIZE);
 247
 248         full_offset = page->index;              /* NB: using 64bit number */
 249         full_offset <<= PAGE_CACHE_SHIFT;       /* offset from file start */
 250         full_offset += offset;                  /* offset from page start */
 251
 252         if (full_offset < iomapp->iomap_offset)
 253                 return NULL;
 254         if (iomapp->iomap_offset + (iomapp->iomap_bsize -1) >= full_offset)
 255                 return iomapp;
 256         return NULL;
 257 }
 258
 259 STATIC void
 260 xfs_map_at_offset(
 261         struct page             *page,
 262         struct buffer_head      *bh,
 263         unsigned long           offset,
 264         int                     block_bits,
 265         xfs_iomap_t             *iomapp)
 266 {
 267         xfs_daddr_t             bn;
 268         loff_t                  delta;
 269         int                     sector_shift;
 270
 271         ASSERT(!(iomapp->iomap_flags & IOMAP_HOLE));
 272         ASSERT(!(iomapp->iomap_flags & IOMAP_DELAY));
 273         ASSERT(iomapp->iomap_bn != IOMAP_DADDR_NULL);
 274
 275         delta = page->index;
 276         delta <<= PAGE_CACHE_SHIFT;
 277         delta += offset;
 278         delta -= iomapp->iomap_offset;
 279         delta >>= block_bits;
 280
 281         sector_shift = block_bits - BBSHIFT;
 282         bn = iomapp->iomap_bn >> sector_shift;
 283         bn += delta;
 284         BUG_ON(!bn && !(iomapp->iomap_flags & IOMAP_REALTIME));
 285         ASSERT((bn << sector_shift) >= iomapp->iomap_bn);
 286
 287         lock_buffer(bh);
 288         bh->b_blocknr = bn;
 289         bh->b_bdev = iomapp->iomap_target->pbr_bdev;
 290         set_buffer_mapped(bh);
 291         clear_buffer_delay(bh);
 292 }
 293
 294 /*
 295  * Look for a page at index which is unlocked and contains our
 296  * unwritten extent flagged buffers at its head.  Returns page
 297  * locked and with an extra reference count, and length of the
 298  * unwritten extent component on this page that we can write,
 299  * in units of filesystem blocks.
 300  */
 301 STATIC struct page *
 302 xfs_probe_unwritten_page(
 303         struct address_space    *mapping,
 304         pgoff_t                 index,
 305         xfs_iomap_t             *iomapp,
 306         xfs_ioend_t             *ioend,
 307         unsigned long           max_offset,
 308         unsigned long           *fsbs,
 309         unsigned int            bbits)
 310 {
 311         struct page             *page;
 312
 313         page = find_trylock_page(mapping, index);
 314         if (!page)
 315                 return NULL;
 316         if (PageWriteback(page))
 317                 goto out;
 318
 319         if (page->mapping && page_has_buffers(page)) {
 320                 struct buffer_head      *bh, *head;
 321                 unsigned long           p_offset = 0;
 322
 323                 *fsbs = 0;
 324                 bh = head = page_buffers(page);
 325                 do {
 326                         if (!buffer_unwritten(bh) || !buffer_uptodate(bh))
 327                                 break;
 328                         if (!xfs_offset_to_map(page, iomapp, p_offset))
 329                                 break;
 330                         if (p_offset >= max_offset)
 331                                 break;
 332                         xfs_map_at_offset(page, bh, p_offset, bbits, iomapp);
 333                         set_buffer_unwritten_io(bh);
 334                         bh->b_private = ioend;
 335                         p_offset += bh->b_size;
 336                         (*fsbs)++;
 337                 } while ((bh = bh->b_this_page) != head);
 338
 339                 if (p_offset)
 340                         return page;
 341         }
 342
 343 out:
 344         unlock_page(page);
 345         return NULL;
 346 }
 347
 348 /*
 349  * Look for a page at index which is unlocked and not mapped
 350  * yet - clustering for mmap write case.
 351  */
 352 STATIC unsigned int
 353 xfs_probe_unmapped_page(
 354         struct address_space    *mapping,
 355         pgoff_t                 index,
 356         unsigned int            pg_offset)
 357 {
 358         struct page             *page;
 359         int                     ret = 0;
 360
 361         page = find_trylock_page(mapping, index);
 362         if (!page)
 363                 return 0;
 364         if (PageWriteback(page))
 365                 goto out;
 366
 367         if (page->mapping && PageDirty(page)) {
 368                 if (page_has_buffers(page)) {
 369                         struct buffer_head      *bh, *head;
 370
 371                         bh = head = page_buffers(page);
 372                         do {
 373                                 if (buffer_mapped(bh) || !buffer_uptodate(bh))
 374                                         break;
 375                                 ret += bh->b_size;
 376                                 if (ret >= pg_offset)
 377                                         break;
 378                         } while ((bh = bh->b_this_page) != head);
 379                 } else
 380                         ret = PAGE_CACHE_SIZE;
 381         }
 382
 383 out:
 384         unlock_page(page);
 385         return ret;
 386 }
 387
 388 STATIC unsigned int
 389 xfs_probe_unmapped_cluster(
 390         struct inode            *inode,
 391         struct page             *startpage,
 392         struct buffer_head      *bh,
 393         struct buffer_head      *head)
 394 {
 395         pgoff_t                 tindex, tlast, tloff;
 396         unsigned int            pg_offset, len, total = 0;
 397         struct address_space    *mapping = inode->i_mapping;
 398
 399         /* First sum forwards in this page */
 400         do {
 401                 if (buffer_mapped(bh))
 402                         break;
 403                 total += bh->b_size;
 404         } while ((bh = bh->b_this_page) != head);
 405
 406         /* If we reached the end of the page, sum forwards in
 407          * following pages.
 408          */
 409         if (bh == head) {
 410                 tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
 411                 /* Prune this back to avoid pathological behavior */
 412                 tloff = min(tlast, startpage->index + 64);
 413                 for (tindex = startpage->index + 1; tindex < tloff; tindex++) {
 414                         len = xfs_probe_unmapped_page(mapping, tindex,
 415                                                         PAGE_CACHE_SIZE);
 416                         if (!len)
 417                                 return total;
 418                         total += len;
 419                 }
 420                 if (tindex == tlast &&
 421                     (pg_offset = i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
 422                         total += xfs_probe_unmapped_page(mapping,
 423                                                         tindex, pg_offset);
 424                 }
 425         }
 426         return total;
 427 }
 428
 429 /*
 430  * Probe for a given page (index) in the inode and test if it is delayed
 431  * and without unwritten buffers.  Returns page locked and with an extra
 432  * reference count.
 433  */
 434 STATIC struct page *
 435 xfs_probe_delalloc_page(
 436         struct inode            *inode,
 437         pgoff_t                 index)
 438 {
 439         struct page             *page;
 440
 441         page = find_trylock_page(inode->i_mapping, index);
 442         if (!page)
 443                 return NULL;
 444         if (PageWriteback(page))
 445                 goto out;
 446
 447         if (page->mapping && page_has_buffers(page)) {
 448                 struct buffer_head      *bh, *head;
 449                 int                     acceptable = 0;
 450
 451                 bh = head = page_buffers(page);
 452                 do {
 453                         if (buffer_unwritten(bh)) {
 454                                 acceptable = 0;
 455                                 break;
 456                         } else if (buffer_delay(bh)) {
 457                                 acceptable = 1;
 458                         }
 459                 } while ((bh = bh->b_this_page) != head);
 460
 461                 if (acceptable)
 462                         return page;
 463         }
 464
 465 out:
 466         unlock_page(page);
 467         return NULL;
 468 }
 469
 470 STATIC int
 471 xfs_map_unwritten(
 472         struct inode            *inode,
 473         struct page             *start_page,
 474         struct buffer_head      *head,
 475         struct buffer_head      *curr,
 476         unsigned long           p_offset,
 477         int                     block_bits,
 478         xfs_iomap_t             *iomapp,
 479         struct writeback_control *wbc,
 480         int                     startio,
 481         int                     all_bh)
 482 {
 483         struct buffer_head      *bh = curr;
 484         xfs_iomap_t             *tmp;
 485         xfs_ioend_t             *ioend;
 486         loff_t                  offset;
 487         unsigned long           nblocks = 0;
 488
 489         offset = start_page->index;
 490         offset <<= PAGE_CACHE_SHIFT;
 491         offset += p_offset;
 492
 493         ioend = xfs_alloc_ioend(inode);
 494
 495         /* First map forwards in the page consecutive buffers
 496          * covering this unwritten extent
 497          */
 498         do {
 499                 if (!buffer_unwritten(bh))
 500                         break;
 501                 tmp = xfs_offset_to_map(start_page, iomapp, p_offset);
 502                 if (!tmp)
 503                         break;
 504                 xfs_map_at_offset(start_page, bh, p_offset, block_bits, iomapp);
 505                 set_buffer_unwritten_io(bh);
 506                 bh->b_private = ioend;
 507                 p_offset += bh->b_size;
 508                 nblocks++;
 509         } while ((bh = bh->b_this_page) != head);
 510
 511         atomic_add(nblocks, &ioend->io_remaining);
 512
 513         /* If we reached the end of the page, map forwards in any
 514          * following pages which are also covered by this extent.
 515          */
 516         if (bh == head) {
 517                 struct address_space    *mapping = inode->i_mapping;
 518                 pgoff_t                 tindex, tloff, tlast;
 519                 unsigned long           bs;
 520                 unsigned int            pg_offset, bbits = inode->i_blkbits;
 521                 struct page             *page;
 522
 523                 tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
 524                 tloff = (iomapp->iomap_offset + iomapp->iomap_bsize) >> PAGE_CACHE_SHIFT;
 525                 tloff = min(tlast, tloff);
 526                 for (tindex = start_page->index + 1; tindex < tloff; tindex++) {
 527                         page = xfs_probe_unwritten_page(mapping,
 528                                                 tindex, iomapp, ioend,
 529                                                 PAGE_CACHE_SIZE, &bs, bbits);
 530                         if (!page)
 531                                 break;
 532                         nblocks += bs;
 533                         atomic_add(bs, &ioend->io_remaining);
 534                         xfs_convert_page(inode, page, iomapp, wbc, ioend,
 535                                                         startio, all_bh);
 536                         /* stop if converting the next page might add
 537                          * enough blocks that the corresponding byte
 538                          * count won't fit in our ulong page buf length */
 539                         if (nblocks >= ((ULONG_MAX - PAGE_SIZE) >> block_bits))
 540                                 goto enough;
 541                 }
 542
 543                 if (tindex == tlast &&
 544                     (pg_offset = (i_size_read(inode) & (PAGE_CACHE_SIZE - 1)))) {
 545                         page = xfs_probe_unwritten_page(mapping,
 546                                                         tindex, iomapp, ioend,
 547                                                         pg_offset, &bs, bbits);
 548                         if (page) {
 549                                 nblocks += bs;
 550                                 atomic_add(bs, &ioend->io_remaining);
 551                                 xfs_convert_page(inode, page, iomapp, wbc, ioend,
 552                                                         startio, all_bh);
 553                                 if (nblocks >= ((ULONG_MAX - PAGE_SIZE) >> block_bits))
 554                                         goto enough;
 555                         }
 556                 }
 557         }
 558
 559 enough:
 560         ioend->io_size = (xfs_off_t)nblocks << block_bits;
 561         ioend->io_offset = offset;
 562         xfs_finish_ioend(ioend);
 563         return 0;
 564 }
 565
 566 STATIC void
 567 xfs_submit_page(
 568         struct page             *page,
 569         struct writeback_control *wbc,
 570         struct buffer_head      *bh_arr[],
 571         int                     bh_count,
 572         int                     probed_page,
 573         int                     clear_dirty)
 574 {
 575         struct buffer_head      *bh;
 576         int                     i;
 577
 578         BUG_ON(PageWriteback(page));
 579         if (bh_count)
 580                 set_page_writeback(page);
 581         if (clear_dirty)
 582                 clear_page_dirty(page);
 583         unlock_page(page);
 584
 585         if (bh_count) {
 586                 for (i = 0; i < bh_count; i++) {
 587                         bh = bh_arr[i];
 588                         mark_buffer_async_write(bh);
 589                         if (buffer_unwritten(bh))
 590                                 set_buffer_unwritten_io(bh);
 591                         set_buffer_uptodate(bh);
 592                         clear_buffer_dirty(bh);
 593                 }
 594
 595                 for (i = 0; i < bh_count; i++)
 596                         submit_bh(WRITE, bh_arr[i]);
 597
 598                 if (probed_page && clear_dirty)
 599                         wbc->nr_to_write--;     /* Wrote an "extra" page */
 600         }
 601 }
 602
 603 /*
 604  * Allocate & map buffers for page given the extent map. Write it out.
 605  * except for the original page of a writepage, this is called on
 606  * delalloc/unwritten pages only, for the original page it is possible
 607  * that the page has no mapping at all.
 608  */
 609 STATIC void
 610 xfs_convert_page(
 611         struct inode            *inode,
 612         struct page             *page,
 613         xfs_iomap_t             *iomapp,
 614         struct writeback_control *wbc,
 615         void                    *private,
 616         int                     startio,
 617         int                     all_bh)
 618 {
 619         struct buffer_head      *bh_arr[MAX_BUF_PER_PAGE], *bh, *head;
 620         xfs_iomap_t             *mp = iomapp, *tmp;
 621         unsigned long           offset, end_offset;
 622         int                     index = 0;
 623         int                     bbits = inode->i_blkbits;
 624         int                     len, page_dirty;
 625
 626         end_offset = (i_size_read(inode) & (PAGE_CACHE_SIZE - 1));
 627
 628         /*
 629          * page_dirty is initially a count of buffers on the page before
 630          * EOF and is decrememted as we move each into a cleanable state.
 631          */
 632         len = 1 << inode->i_blkbits;
 633         end_offset = max(end_offset, PAGE_CACHE_SIZE);
 634         end_offset = roundup(end_offset, len);
 635         page_dirty = end_offset / len;
 636
 637         offset = 0;
 638         bh = head = page_buffers(page);
 639         do {
 640                 if (offset >= end_offset)
 641                         break;
 642                 if (!(PageUptodate(page) || buffer_uptodate(bh)))
 643                         continue;
 644                 if (buffer_mapped(bh) && all_bh &&
 645                     !(buffer_unwritten(bh) || buffer_delay(bh))) {
 646                         if (startio) {
 647                                 lock_buffer(bh);
 648                                 bh_arr[index++] = bh;
 649                                 page_dirty--;
 650                         }
 651                         continue;
 652                 }
 653                 tmp = xfs_offset_to_map(page, mp, offset);
 654                 if (!tmp)
 655                         continue;
 656                 ASSERT(!(tmp->iomap_flags & IOMAP_HOLE));
 657                 ASSERT(!(tmp->iomap_flags & IOMAP_DELAY));
 658
 659                 /* If this is a new unwritten extent buffer (i.e. one
 660                  * that we haven't passed in private data for, we must
 661                  * now map this buffer too.
 662                  */
 663                 if (buffer_unwritten(bh) && !bh->b_end_io) {
 664                         ASSERT(tmp->iomap_flags & IOMAP_UNWRITTEN);
 665                         xfs_map_unwritten(inode, page, head, bh, offset,
 666                                         bbits, tmp, wbc, startio, all_bh);
 667                 } else if (! (buffer_unwritten(bh) && buffer_locked(bh))) {
 668                         xfs_map_at_offset(page, bh, offset, bbits, tmp);
 669                         if (buffer_unwritten(bh)) {
 670                                 set_buffer_unwritten_io(bh);
 671                                 bh->b_private = private;
 672                                 ASSERT(private);
 673                         }
 674                 }
 675                 if (startio) {
 676                         bh_arr[index++] = bh;
 677                 } else {
 678                         set_buffer_dirty(bh);
 679                         unlock_buffer(bh);
 680                         mark_buffer_dirty(bh);
 681                 }
 682                 page_dirty--;
 683         } while (offset += len, (bh = bh->b_this_page) != head);
 684
 685         if (startio && index) {
 686                 xfs_submit_page(page, wbc, bh_arr, index, 1, !page_dirty);
 687         } else {
 688                 unlock_page(page);
 689         }
 690 }
 691
 692 /*
 693  * Convert & write out a cluster of pages in the same extent as defined
 694  * by mp and following the start page.
 695  */
 696 STATIC void
 697 xfs_cluster_write(
 698         struct inode            *inode,
 699         pgoff_t                 tindex,
 700         xfs_iomap_t             *iomapp,
 701         struct writeback_control *wbc,
 702         int                     startio,
 703         int                     all_bh,
 704         pgoff_t                 tlast)
 705 {
 706         struct page             *page;
 707
 708         for (; tindex <= tlast; tindex++) {
 709                 page = xfs_probe_delalloc_page(inode, tindex);
 710                 if (!page)
 711                         break;
 712                 xfs_convert_page(inode, page, iomapp, wbc, NULL,
 713                                 startio, all_bh);
 714         }
 715 }
 716
 717 /*
 718  * Calling this without startio set means we are being asked to make a dirty
 719  * page ready for freeing it's buffers.  When called with startio set then
 720  * we are coming from writepage.
 721  *
 722  * When called with startio set it is important that we write the WHOLE
 723  * page if possible.
 724  * The bh->b_state's cannot know if any of the blocks or which block for
 725  * that matter are dirty due to mmap writes, and therefore bh uptodate is
 726  * only vaild if the page itself isn't completely uptodate.  Some layers
 727  * may clear the page dirty flag prior to calling write page, under the
 728  * assumption the entire page will be written out; by not writing out the
 729  * whole page the page can be reused before all valid dirty data is
 730  * written out.  Note: in the case of a page that has been dirty'd by
 731  * mapwrite and but partially setup by block_prepare_write the
 732  * bh->b_states's will not agree and only ones setup by BPW/BCW will have
 733  * valid state, thus the whole page must be written out thing.
 734  */
 735
 736 STATIC int
 737 xfs_page_state_convert(
 738         struct inode    *inode,
 739         struct page     *page,
 740         struct writeback_control *wbc,
 741         int             startio,
 742         int             unmapped) /* also implies page uptodate */
 743 {
 744         struct buffer_head      *bh_arr[MAX_BUF_PER_PAGE], *bh, *head;
 745         xfs_iomap_t             *iomp, iomap;
 746         loff_t                  offset;
 747         unsigned long           p_offset = 0;
 748         __uint64_t              end_offset;
 749         pgoff_t                 end_index, last_index, tlast;
 750         int                     len, err, i, cnt = 0, uptodate = 1;
 751         int                     flags;
 752         int                     page_dirty;
 753
 754         /* wait for other IO threads? */
 755         flags = (startio && wbc->sync_mode != WB_SYNC_NONE) ? 0 : BMAPI_TRYLOCK;
 756
 757         /* Is this page beyond the end of the file? */
 758         offset = i_size_read(inode);
 759         end_index = offset >> PAGE_CACHE_SHIFT;
 760         last_index = (offset - 1) >> PAGE_CACHE_SHIFT;
 761         if (page->index >= end_index) {
 762                 if ((page->index >= end_index + 1) ||
 763                     !(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
 764                         err = -EIO;
 765                         goto error;
 766                 }
 767         }
 768
 769         end_offset = min_t(unsigned long long,
 770                         (loff_t)(page->index + 1) << PAGE_CACHE_SHIFT, offset);
 771         offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
 772
 773         /*
 774          * page_dirty is initially a count of buffers on the page before
 775          * EOF and is decrememted as we move each into a cleanable state.
 776          */
 777         len = 1 << inode->i_blkbits;
 778         p_offset = max(p_offset, PAGE_CACHE_SIZE);
 779         p_offset = roundup(p_offset, len);
 780         page_dirty = p_offset / len;
 781
 782         iomp = NULL;
 783         p_offset = 0;
 784         bh = head = page_buffers(page);
 785
 786         do {
 787                 if (offset >= end_offset)
 788                         break;
 789                 if (!buffer_uptodate(bh))
 790                         uptodate = 0;
 791                 if (!(PageUptodate(page) || buffer_uptodate(bh)) && !startio)
 792                         continue;
 793
 794                 if (iomp) {
 795                         iomp = xfs_offset_to_map(page, &iomap, p_offset);
 796                 }
 797
 798                 /*
 799                  * First case, map an unwritten extent and prepare for
 800                  * extent state conversion transaction on completion.
 801                  */
 802                 if (buffer_unwritten(bh)) {
 803                         if (!startio)
 804                                 continue;
 805                         if (!iomp) {
 806                                 err = xfs_map_blocks(inode, offset, len, &iomap,
 807                                                 BMAPI_WRITE|BMAPI_IGNSTATE);
 808                                 if (err) {
 809                                         goto error;
 810                                 }
 811                                 iomp = xfs_offset_to_map(page, &iomap,
 812                                                                 p_offset);
 813                         }
 814                         if (iomp) {
 815                                 if (!bh->b_end_io) {
 816                                         err = xfs_map_unwritten(inode, page,
 817                                                         head, bh, p_offset,
 818                                                         inode->i_blkbits, iomp,
 819                                                         wbc, startio, unmapped);
 820                                         if (err) {
 821                                                 goto error;
 822                                         }
 823                                 } else {
 824                                         set_bit(BH_Lock, &bh->b_state);
 825                                 }
 826                                 BUG_ON(!buffer_locked(bh));
 827                                 bh_arr[cnt++] = bh;
 828                                 page_dirty--;
 829                         }
 830                 /*
 831                  * Second case, allocate space for a delalloc buffer.
 832                  * We can return EAGAIN here in the release page case.
 833                  */
 834                 } else if (buffer_delay(bh)) {
 835                         if (!iomp) {
 836                                 err = xfs_map_blocks(inode, offset, len, &iomap,
 837                                                 BMAPI_ALLOCATE | flags);
 838                                 if (err) {
 839                                         goto error;
 840                                 }
 841                                 iomp = xfs_offset_to_map(page, &iomap,
 842                                                                 p_offset);
 843                         }
 844                         if (iomp) {
 845                                 xfs_map_at_offset(page, bh, p_offset,
 846                                                 inode->i_blkbits, iomp);
 847                                 if (startio) {
 848                                         bh_arr[cnt++] = bh;
 849                                 } else {
 850                                         set_buffer_dirty(bh);
 851                                         unlock_buffer(bh);
 852                                         mark_buffer_dirty(bh);
 853                                 }
 854                                 page_dirty--;
 855                         }
 856                 } else if ((buffer_uptodate(bh) || PageUptodate(page)) &&
 857                            (unmapped || startio)) {
 858
 859                         if (!buffer_mapped(bh)) {
 860                                 int     size;
 861
 862                                 /*
 863                                  * Getting here implies an unmapped buffer
 864                                  * was found, and we are in a path where we
 865                                  * need to write the whole page out.
 866                                  */
 867                                 if (!iomp) {
 868                                         size = xfs_probe_unmapped_cluster(
 869                                                         inode, page, bh, head);
 870                                         err = xfs_map_blocks(inode, offset,
 871                                                         size, &iomap,
 872                                                         BMAPI_WRITE|BMAPI_MMAP);
 873                                         if (err) {
 874                                                 goto error;
 875                                         }
 876                                         iomp = xfs_offset_to_map(page, &iomap,
 877                                                                      p_offset);
 878                                 }
 879                                 if (iomp) {
 880                                         xfs_map_at_offset(page,
 881                                                         bh, p_offset,
 882                                                         inode->i_blkbits, iomp);
 883                                         if (startio) {
 884                                                 bh_arr[cnt++] = bh;
 885                                         } else {
 886                                                 set_buffer_dirty(bh);
 887                                                 unlock_buffer(bh);
 888                                                 mark_buffer_dirty(bh);
 889                                         }
 890                                         page_dirty--;
 891                                 }
 892                         } else if (startio) {
 893                                 if (buffer_uptodate(bh) &&
 894                                     !test_and_set_bit(BH_Lock, &bh->b_state)) {
 895                                         bh_arr[cnt++] = bh;
 896                                         page_dirty--;
 897                                 }
 898                         }
 899                 }
 900         } while (offset += len, p_offset += len,
 901                 ((bh = bh->b_this_page) != head));
 902
 903         if (uptodate && bh == head)
 904                 SetPageUptodate(page);
 905
 906         if (startio) {
 907                 xfs_submit_page(page, wbc, bh_arr, cnt, 0, !page_dirty);
 908         }
 909
 910         if (iomp) {
 911                 offset = (iomp->iomap_offset + iomp->iomap_bsize - 1) >>
 912                                         PAGE_CACHE_SHIFT;
 913                 tlast = min_t(pgoff_t, offset, last_index);
 914                 xfs_cluster_write(inode, page->index + 1, iomp, wbc,
 915                                         startio, unmapped, tlast);
 916         }
 917
 918         return page_dirty;
 919
 920 error:
 921         for (i = 0; i < cnt; i++) {
 922                 unlock_buffer(bh_arr[i]);
 923         }
 924
 925         /*
 926          * If it's delalloc and we have nowhere to put it,
 927          * throw it away, unless the lower layers told
 928          * us to try again.
 929          */
 930         if (err != -EAGAIN) {
 931                 if (!unmapped) {
 932                         block_invalidatepage(page, 0);
 933                 }
 934                 ClearPageUptodate(page);
 935         }
 936         return err;
 937 }
 938
 939 STATIC int
 940 __linvfs_get_block(
 941         struct inode            *inode,
 942         sector_t                iblock,
 943         unsigned long           blocks,
 944         struct buffer_head      *bh_result,
 945         int                     create,
 946         int                     direct,
 947         bmapi_flags_t           flags)
 948 {
 949         vnode_t                 *vp = LINVFS_GET_VP(inode);
 950         xfs_iomap_t             iomap;
 951         int                     retpbbm = 1;
 952         int                     error;
 953         ssize_t                 size;
 954         loff_t                  offset = (loff_t)iblock << inode->i_blkbits;
 955
 956         if (blocks)
 957                 size = blocks << inode->i_blkbits;
 958         else
 959                 size = 1 << inode->i_blkbits;
 960
 961         VOP_BMAP(vp, offset, size,
 962                 create ? flags : BMAPI_READ, &iomap, &retpbbm, error);
 963         if (error)
 964                 return -error;
 965
 966         if (retpbbm == 0)
 967                 return 0;
 968
 969         if (iomap.iomap_bn != IOMAP_DADDR_NULL) {
 970                 xfs_daddr_t             bn;
 971                 loff_t                  delta;
 972
 973                 /* For unwritten extents do not report a disk address on
 974                  * the read case (treat as if we're reading into a hole).
 975                  */
 976                 if (create || !(iomap.iomap_flags & IOMAP_UNWRITTEN)) {
 977                         delta = offset - iomap.iomap_offset;
 978                         delta >>= inode->i_blkbits;
 979
 980                         bn = iomap.iomap_bn >> (inode->i_blkbits - BBSHIFT);
 981                         bn += delta;
 982                         BUG_ON(!bn && !(iomap.iomap_flags & IOMAP_REALTIME));
 983                         bh_result->b_blocknr = bn;
 984                         set_buffer_mapped(bh_result);
 985                 }
 986                 if (create && (iomap.iomap_flags & IOMAP_UNWRITTEN)) {
 987                         if (direct)
 988                                 bh_result->b_private = inode;
 989                         set_buffer_unwritten(bh_result);
 990                         set_buffer_delay(bh_result);
 991                 }
 992         }
 993
 994         /* If this is a realtime file, data might be on a new device */
 995         bh_result->b_bdev = iomap.iomap_target->pbr_bdev;
 996
 997         /* If we previously allocated a block out beyond eof and
 998          * we are now coming back to use it then we will need to
 999          * flag it as new even if it has a disk address.
1000          */
1001         if (create &&
1002             ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
1003              (offset >= i_size_read(inode)) || (iomap.iomap_flags & IOMAP_NEW))) {
1004                 set_buffer_new(bh_result);
1005         }
1006
1007         if (iomap.iomap_flags & IOMAP_DELAY) {
1008                 BUG_ON(direct);
1009                 if (create) {
1010                         set_buffer_uptodate(bh_result);
1011                         set_buffer_mapped(bh_result);
1012                         set_buffer_delay(bh_result);
1013                 }
1014         }
1015
1016         if (blocks) {
1017                 bh_result->b_size = (ssize_t)min(
1018                         (loff_t)(iomap.iomap_bsize - iomap.iomap_delta),
1019                         (loff_t)(blocks << inode->i_blkbits));
1020         }
1021
1022         return 0;
1023 }
1024
1025 int
1026 linvfs_get_block(
1027         struct inode            *inode,
1028         sector_t                iblock,
1029         struct buffer_head      *bh_result,
1030         int                     create)
1031 {
1032         return __linvfs_get_block(inode, iblock, 0, bh_result,
1033                                         create, 0, BMAPI_WRITE);
1034 }
1035
1036 STATIC int
1037 linvfs_get_blocks_direct(
1038         struct inode            *inode,
1039         sector_t                iblock,
1040         unsigned long           max_blocks,
1041         struct buffer_head      *bh_result,
1042         int                     create)
1043 {
1044         return __linvfs_get_block(inode, iblock, max_blocks, bh_result,
1045                                         create, 1, BMAPI_WRITE|BMAPI_DIRECT);
1046 }
1047
1048 STATIC void
1049 linvfs_end_io_direct(
1050         struct kiocb    *iocb,
1051         loff_t          offset,
1052         ssize_t         size,
1053         void            *private)
1054 {
1055         xfs_ioend_t     *ioend = iocb->private;
1056
1057         /*
1058          * Non-NULL private data means we need to issue a transaction to
1059          * convert a range from unwritten to written extents.  This needs
1060          * to happen from process contect but aio+dio I/O completion
1061          * happens from irq context so we need to defer it to a workqueue.
1062          * This is not nessecary for synchronous direct I/O, but we do
1063          * it anyway to keep the code uniform and simpler.
1064          *
1065          * The core direct I/O code might be changed to always call the
1066          * completion handler in the future, in which case all this can
1067          * go away.
1068          */
1069         if (private && size > 0) {
1070                 ioend->io_offset = offset;
1071                 ioend->io_size = size;
1072                 xfs_finish_ioend(ioend);
1073         } else {
1074                 ASSERT(size >= 0);
1075                 xfs_destroy_ioend(ioend);
1076         }
1077
1078         /*
1079          * blockdev_direct_IO can return an error even afer the I/O
1080          * completion handler was called.  Thus we need to protect
1081          * against double-freeing.
1082          */
1083         iocb->private = NULL;
1084 }
1085
1086 STATIC ssize_t
1087 linvfs_direct_IO(
1088         int                     rw,
1089         struct kiocb            *iocb,
1090         const struct iovec      *iov,
1091         loff_t                  offset,
1092         unsigned long           nr_segs)
1093 {
1094         struct file     *file = iocb->ki_filp;
1095         struct inode    *inode = file->f_mapping->host;
1096         vnode_t         *vp = LINVFS_GET_VP(inode);
1097         xfs_iomap_t     iomap;
1098         int             maps = 1;
1099         int             error;
1100         ssize_t         ret;
1101
1102         VOP_BMAP(vp, offset, 0, BMAPI_DEVICE, &iomap, &maps, error);
1103         if (error)
1104                 return -error;
1105
1106         iocb->private = xfs_alloc_ioend(inode);
1107
1108         ret = blockdev_direct_IO_own_locking(rw, iocb, inode,
1109                 iomap.iomap_target->pbr_bdev,
1110                 iov, offset, nr_segs,
1111                 linvfs_get_blocks_direct,
1112                 linvfs_end_io_direct);
1113
1114         if (unlikely(ret <= 0 && iocb->private))
1115                 xfs_destroy_ioend(iocb->private);
1116         return ret;
1117 }
1118
1119
1120 STATIC sector_t
1121 linvfs_bmap(
1122         struct address_space    *mapping,
1123         sector_t                block)
1124 {
1125         struct inode            *inode = (struct inode *)mapping->host;
1126         vnode_t                 *vp = LINVFS_GET_VP(inode);
1127         int                     error;
1128
1129         vn_trace_entry(vp, "linvfs_bmap", (inst_t *)__return_address);
1130
1131         VOP_RWLOCK(vp, VRWLOCK_READ);
1132         VOP_FLUSH_PAGES(vp, (xfs_off_t)0, -1, 0, FI_REMAPF, error);
1133         VOP_RWUNLOCK(vp, VRWLOCK_READ);
1134         return generic_block_bmap(mapping, block, linvfs_get_block);
1135 }
1136
1137 STATIC int
1138 linvfs_readpage(
1139         struct file             *unused,
1140         struct page             *page)
1141 {
1142         return mpage_readpage(page, linvfs_get_block);
1143 }
1144
1145 STATIC int
1146 linvfs_readpages(
1147         struct file             *unused,
1148         struct address_space    *mapping,
1149         struct list_head        *pages,
1150         unsigned                nr_pages)
1151 {
1152         return mpage_readpages(mapping, pages, nr_pages, linvfs_get_block);
1153 }
1154
1155 STATIC void
1156 xfs_count_page_state(
1157         struct page             *page,
1158         int                     *delalloc,
1159         int                     *unmapped,
1160         int                     *unwritten)
1161 {
1162         struct buffer_head      *bh, *head;
1163
1164         *delalloc = *unmapped = *unwritten = 0;
1165
1166         bh = head = page_buffers(page);
1167         do {
1168                 if (buffer_uptodate(bh) && !buffer_mapped(bh))
1169                         (*unmapped) = 1;
1170                 else if (buffer_unwritten(bh) && !buffer_delay(bh))
1171                         clear_buffer_unwritten(bh);
1172                 else if (buffer_unwritten(bh))
1173                         (*unwritten) = 1;
1174                 else if (buffer_delay(bh))
1175                         (*delalloc) = 1;
1176         } while ((bh = bh->b_this_page) != head);
1177 }
1178
1179
1180 /*
1181  * writepage: Called from one of two places:
1182  *
1183  * 1. we are flushing a delalloc buffer head.
1184  *
1185  * 2. we are writing out a dirty page. Typically the page dirty
1186  *    state is cleared before we get here. In this case is it
1187  *    conceivable we have no buffer heads.
1188  *
1189  * For delalloc space on the page we need to allocate space and
1190  * flush it. For unmapped buffer heads on the page we should
1191  * allocate space if the page is uptodate. For any other dirty
1192  * buffer heads on the page we should flush them.
1193  *
1194  * If we detect that a transaction would be required to flush
1195  * the page, we have to check the process flags first, if we
1196  * are already in a transaction or disk I/O during allocations
1197  * is off, we need to fail the writepage and redirty the page.
1198  */
1199
1200 STATIC int
1201 linvfs_writepage(
1202         struct page             *page,
1203         struct writeback_control *wbc)
1204 {
1205         int                     error;
1206         int                     need_trans;
1207         int                     delalloc, unmapped, unwritten;
1208         struct inode            *inode = page->mapping->host;
1209
1210         xfs_page_trace(XFS_WRITEPAGE_ENTER, inode, page, 0);
1211
1212         /*
1213          * We need a transaction if:
1214          *  1. There are delalloc buffers on the page
1215          *  2. The page is uptodate and we have unmapped buffers
1216          *  3. The page is uptodate and we have no buffers
1217          *  4. There are unwritten buffers on the page
1218          */
1219
1220         if (!page_has_buffers(page)) {
1221                 unmapped = 1;
1222                 need_trans = 1;
1223         } else {
1224                 xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
1225                 if (!PageUptodate(page))
1226                         unmapped = 0;
1227                 need_trans = delalloc + unmapped + unwritten;
1228         }
1229
1230         /*
1231          * If we need a transaction and the process flags say
1232          * we are already in a transaction, or no IO is allowed
1233          * then mark the page dirty again and leave the page
1234          * as is.
1235          */
1236         if (PFLAGS_TEST_FSTRANS() && need_trans)
1237                 goto out_fail;
1238
1239         /*
1240          * Delay hooking up buffer heads until we have
1241          * made our go/no-go decision.
1242          */
1243         if (!page_has_buffers(page))
1244                 create_empty_buffers(page, 1 << inode->i_blkbits, 0);
1245
1246         /*
1247          * Convert delayed allocate, unwritten or unmapped space
1248          * to real space and flush out to disk.
1249          */
1250         error = xfs_page_state_convert(inode, page, wbc, 1, unmapped);
1251         if (error == -EAGAIN)
1252                 goto out_fail;
1253         if (unlikely(error < 0))
1254                 goto out_unlock;
1255
1256         return 0;
1257
1258 out_fail:
1259         redirty_page_for_writepage(wbc, page);
1260         unlock_page(page);
1261         return 0;
1262 out_unlock:
1263         unlock_page(page);
1264         return error;
1265 }
1266
1267 STATIC int
1268 linvfs_invalidate_page(
1269         struct page             *page,
1270         unsigned long           offset)
1271 {
1272         xfs_page_trace(XFS_INVALIDPAGE_ENTER,
1273                         page->mapping->host, page, offset);
1274         return block_invalidatepage(page, offset);
1275 }
1276
1277 /*
1278  * Called to move a page into cleanable state - and from there
1279  * to be released. Possibly the page is already clean. We always
1280  * have buffer heads in this call.
1281  *
1282  * Returns 0 if the page is ok to release, 1 otherwise.
1283  *
1284  * Possible scenarios are:
1285  *
1286  * 1. We are being called to release a page which has been written
1287  *    to via regular I/O. buffer heads will be dirty and possibly
1288  *    delalloc. If no delalloc buffer heads in this case then we
1289  *    can just return zero.
1290  *
1291  * 2. We are called to release a page which has been written via
1292  *    mmap, all we need to do is ensure there is no delalloc
1293  *    state in the buffer heads, if not we can let the caller
1294  *    free them and we should come back later via writepage.
1295  */
1296 STATIC int
1297 linvfs_release_page(
1298         struct page             *page,
1299         gfp_t                   gfp_mask)
1300 {
1301         struct inode            *inode = page->mapping->host;
1302         int                     dirty, delalloc, unmapped, unwritten;
1303         struct writeback_control wbc = {
1304                 .sync_mode = WB_SYNC_ALL,
1305                 .nr_to_write = 1,
1306         };
1307
1308         xfs_page_trace(XFS_RELEASEPAGE_ENTER, inode, page, gfp_mask);
1309
1310         xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
1311         if (!delalloc && !unwritten)
1312                 goto free_buffers;
1313
1314         if (!(gfp_mask & __GFP_FS))
1315                 return 0;
1316
1317         /* If we are already inside a transaction or the thread cannot
1318          * do I/O, we cannot release this page.
1319          */
1320         if (PFLAGS_TEST_FSTRANS())
1321                 return 0;
1322
1323         /*
1324          * Convert delalloc space to real space, do not flush the
1325          * data out to disk, that will be done by the caller.
1326          * Never need to allocate space here - we will always
1327          * come back to writepage in that case.
1328          */
1329         dirty = xfs_page_state_convert(inode, page, &wbc, 0, 0);
1330         if (dirty == 0 && !unwritten)
1331                 goto free_buffers;
1332         return 0;
1333
1334 free_buffers:
1335         return try_to_free_buffers(page);
1336 }
1337
1338 STATIC int
1339 linvfs_prepare_write(
1340         struct file             *file,
1341         struct page             *page,
1342         unsigned int            from,
1343         unsigned int            to)
1344 {
1345         return block_prepare_write(page, from, to, linvfs_get_block);
1346 }
1347
1348 struct address_space_operations linvfs_aops = {
1349         .readpage               = linvfs_readpage,
1350         .readpages              = linvfs_readpages,
1351         .writepage              = linvfs_writepage,
1352         .sync_page              = block_sync_page,
1353         .releasepage            = linvfs_release_page,
1354         .invalidatepage         = linvfs_invalidate_page,
1355         .prepare_write          = linvfs_prepare_write,
1356         .commit_write           = generic_commit_write,
1357         .bmap                   = linvfs_bmap,
1358         .direct_IO              = linvfs_direct_IO,
1359 };