fs/ntfs/file.c

   1 /*
   2  * file.c - NTFS kernel file operations.  Part of the Linux-NTFS project.
   3  *
   4  * Copyright (c) 2001-2006 Anton Altaparmakov
   5  *
   6  * This program/include file is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as published
   8  * by the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program/include file is distributed in the hope that it will be
  12  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  13  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program (in the main directory of the Linux-NTFS
  18  * distribution in the file COPYING); if not, write to the Free Software
  19  * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <linux/buffer_head.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/pagevec.h>
  25 #include <linux/sched.h>
  26 #include <linux/swap.h>
  27 #include <linux/uio.h>
  28 #include <linux/writeback.h>
  29
  30 #include <asm/page.h>
  31 #include <asm/uaccess.h>
  32
  33 #include "attrib.h"
  34 #include "bitmap.h"
  35 #include "inode.h"
  36 #include "debug.h"
  37 #include "lcnalloc.h"
  38 #include "malloc.h"
  39 #include "mft.h"
  40 #include "ntfs.h"
  41
  42 /**
  43  * ntfs_file_open - called when an inode is about to be opened
  44  * @vi:         inode to be opened
  45  * @filp:       file structure describing the inode
  46  *
  47  * Limit file size to the page cache limit on architectures where unsigned long
  48  * is 32-bits. This is the most we can do for now without overflowing the page
  49  * cache page index. Doing it this way means we don't run into problems because
  50  * of existing too large files. It would be better to allow the user to read
  51  * the beginning of the file but I doubt very much anyone is going to hit this
  52  * check on a 32-bit architecture, so there is no point in adding the extra
  53  * complexity required to support this.
  54  *
  55  * On 64-bit architectures, the check is hopefully optimized away by the
  56  * compiler.
  57  *
  58  * After the check passes, just call generic_file_open() to do its work.
  59  */
  60 static int ntfs_file_open(struct inode *vi, struct file *filp)
  61 {
  62         if (sizeof(unsigned long) < 8) {
  63                 if (i_size_read(vi) > MAX_LFS_FILESIZE)
  64                         return -EFBIG;
  65         }
  66         return generic_file_open(vi, filp);
  67 }
  68
  69 #ifdef NTFS_RW
  70
  71 /**
  72  * ntfs_attr_extend_initialized - extend the initialized size of an attribute
  73  * @ni:                 ntfs inode of the attribute to extend
  74  * @new_init_size:      requested new initialized size in bytes
  75  * @cached_page:        store any allocated but unused page here
  76  * @lru_pvec:           lru-buffering pagevec of the caller
  77  *
  78  * Extend the initialized size of an attribute described by the ntfs inode @ni
  79  * to @new_init_size bytes.  This involves zeroing any non-sparse space between
  80  * the old initialized size and @new_init_size both in the page cache and on
  81  * disk (if relevant complete pages are already uptodate in the page cache then
  82  * these are simply marked dirty).
  83  *
  84  * As a side-effect, the file size (vfs inode->i_size) may be incremented as,
  85  * in the resident attribute case, it is tied to the initialized size and, in
  86  * the non-resident attribute case, it may not fall below the initialized size.
  87  *
  88  * Note that if the attribute is resident, we do not need to touch the page
  89  * cache at all.  This is because if the page cache page is not uptodate we
  90  * bring it uptodate later, when doing the write to the mft record since we
  91  * then already have the page mapped.  And if the page is uptodate, the
  92  * non-initialized region will already have been zeroed when the page was
  93  * brought uptodate and the region may in fact already have been overwritten
  94  * with new data via mmap() based writes, so we cannot just zero it.  And since
  95  * POSIX specifies that the behaviour of resizing a file whilst it is mmap()ped
  96  * is unspecified, we choose not to do zeroing and thus we do not need to touch
  97  * the page at all.  For a more detailed explanation see ntfs_truncate() in
  98  * fs/ntfs/inode.c.
  99  *
 100  * @cached_page and @lru_pvec are just optimizations for dealing with multiple
 101  * pages.
 102  *
 103  * Return 0 on success and -errno on error.  In the case that an error is
 104  * encountered it is possible that the initialized size will already have been
 105  * incremented some way towards @new_init_size but it is guaranteed that if
 106  * this is the case, the necessary zeroing will also have happened and that all
 107  * metadata is self-consistent.
 108  *
 109  * Locking: i_mutex on the vfs inode corrseponsind to the ntfs inode @ni must be
 110  *          held by the caller.
 111  */
 112 static int ntfs_attr_extend_initialized(ntfs_inode *ni, const s64 new_init_size,
 113                 struct page **cached_page, struct pagevec *lru_pvec)
 114 {
 115         s64 old_init_size;
 116         loff_t old_i_size;
 117         pgoff_t index, end_index;
 118         unsigned long flags;
 119         struct inode *vi = VFS_I(ni);
 120         ntfs_inode *base_ni;
 121         MFT_RECORD *m = NULL;
 122         ATTR_RECORD *a;
 123         ntfs_attr_search_ctx *ctx = NULL;
 124         struct address_space *mapping;
 125         struct page *page = NULL;
 126         u8 *kattr;
 127         int err;
 128         u32 attr_len;
 129
 130         read_lock_irqsave(&ni->size_lock, flags);
 131         old_init_size = ni->initialized_size;
 132         old_i_size = i_size_read(vi);
 133         BUG_ON(new_init_size > ni->allocated_size);
 134         read_unlock_irqrestore(&ni->size_lock, flags);
 135         ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
 136                         "old_initialized_size 0x%llx, "
 137                         "new_initialized_size 0x%llx, i_size 0x%llx.",
 138                         vi->i_ino, (unsigned)le32_to_cpu(ni->type),
 139                         (unsigned long long)old_init_size,
 140                         (unsigned long long)new_init_size, old_i_size);
 141         if (!NInoAttr(ni))
 142                 base_ni = ni;
 143         else
 144                 base_ni = ni->ext.base_ntfs_ino;
 145         /* Use goto to reduce indentation and we need the label below anyway. */
 146         if (NInoNonResident(ni))
 147                 goto do_non_resident_extend;
 148         BUG_ON(old_init_size != old_i_size);
 149         m = map_mft_record(base_ni);
 150         if (IS_ERR(m)) {
 151                 err = PTR_ERR(m);
 152                 m = NULL;
 153                 goto err_out;
 154         }
 155         ctx = ntfs_attr_get_search_ctx(base_ni, m);
 156         if (unlikely(!ctx)) {
 157                 err = -ENOMEM;
 158                 goto err_out;
 159         }
 160         err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
 161                         CASE_SENSITIVE, 0, NULL, 0, ctx);
 162         if (unlikely(err)) {
 163                 if (err == -ENOENT)
 164                         err = -EIO;
 165                 goto err_out;
 166         }
 167         m = ctx->mrec;
 168         a = ctx->attr;
 169         BUG_ON(a->non_resident);
 170         /* The total length of the attribute value. */
 171         attr_len = le32_to_cpu(a->data.resident.value_length);
 172         BUG_ON(old_i_size != (loff_t)attr_len);
 173         /*
 174          * Do the zeroing in the mft record and update the attribute size in
 175          * the mft record.
 176          */
 177         kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
 178         memset(kattr + attr_len, 0, new_init_size - attr_len);
 179         a->data.resident.value_length = cpu_to_le32((u32)new_init_size);
 180         /* Finally, update the sizes in the vfs and ntfs inodes. */
 181         write_lock_irqsave(&ni->size_lock, flags);
 182         i_size_write(vi, new_init_size);
 183         ni->initialized_size = new_init_size;
 184         write_unlock_irqrestore(&ni->size_lock, flags);
 185         goto done;
 186 do_non_resident_extend:
 187         /*
 188          * If the new initialized size @new_init_size exceeds the current file
 189          * size (vfs inode->i_size), we need to extend the file size to the
 190          * new initialized size.
 191          */
 192         if (new_init_size > old_i_size) {
 193                 m = map_mft_record(base_ni);
 194                 if (IS_ERR(m)) {
 195                         err = PTR_ERR(m);
 196                         m = NULL;
 197                         goto err_out;
 198                 }
 199                 ctx = ntfs_attr_get_search_ctx(base_ni, m);
 200                 if (unlikely(!ctx)) {
 201                         err = -ENOMEM;
 202                         goto err_out;
 203                 }
 204                 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
 205                                 CASE_SENSITIVE, 0, NULL, 0, ctx);
 206                 if (unlikely(err)) {
 207                         if (err == -ENOENT)
 208                                 err = -EIO;
 209                         goto err_out;
 210                 }
 211                 m = ctx->mrec;
 212                 a = ctx->attr;
 213                 BUG_ON(!a->non_resident);
 214                 BUG_ON(old_i_size != (loff_t)
 215                                 sle64_to_cpu(a->data.non_resident.data_size));
 216                 a->data.non_resident.data_size = cpu_to_sle64(new_init_size);
 217                 flush_dcache_mft_record_page(ctx->ntfs_ino);
 218                 mark_mft_record_dirty(ctx->ntfs_ino);
 219                 /* Update the file size in the vfs inode. */
 220                 i_size_write(vi, new_init_size);
 221                 ntfs_attr_put_search_ctx(ctx);
 222                 ctx = NULL;
 223                 unmap_mft_record(base_ni);
 224                 m = NULL;
 225         }
 226         mapping = vi->i_mapping;
 227         index = old_init_size >> PAGE_CACHE_SHIFT;
 228         end_index = (new_init_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 229         do {
 230                 /*
 231                  * Read the page.  If the page is not present, this will zero
 232                  * the uninitialized regions for us.
 233                  */
 234                 page = read_cache_page(mapping, index,
 235                                 (filler_t*)mapping->a_ops->readpage, NULL);
 236                 if (IS_ERR(page)) {
 237                         err = PTR_ERR(page);
 238                         goto init_err_out;
 239                 }
 240                 wait_on_page_locked(page);
 241                 if (unlikely(!PageUptodate(page) || PageError(page))) {
 242                         page_cache_release(page);
 243                         err = -EIO;
 244                         goto init_err_out;
 245                 }
 246                 /*
 247                  * Update the initialized size in the ntfs inode.  This is
 248                  * enough to make ntfs_writepage() work.
 249                  */
 250                 write_lock_irqsave(&ni->size_lock, flags);
 251                 ni->initialized_size = (s64)(index + 1) << PAGE_CACHE_SHIFT;
 252                 if (ni->initialized_size > new_init_size)
 253                         ni->initialized_size = new_init_size;
 254                 write_unlock_irqrestore(&ni->size_lock, flags);
 255                 /* Set the page dirty so it gets written out. */
 256                 set_page_dirty(page);
 257                 page_cache_release(page);
 258                 /*
 259                  * Play nice with the vm and the rest of the system.  This is
 260                  * very much needed as we can potentially be modifying the
 261                  * initialised size from a very small value to a really huge
 262                  * value, e.g.
 263                  *      f = open(somefile, O_TRUNC);
 264                  *      truncate(f, 10GiB);
 265                  *      seek(f, 10GiB);
 266                  *      write(f, 1);
 267                  * And this would mean we would be marking dirty hundreds of
 268                  * thousands of pages or as in the above example more than
 269                  * two and a half million pages!
 270                  *
 271                  * TODO: For sparse pages could optimize this workload by using
 272                  * the FsMisc / MiscFs page bit as a "PageIsSparse" bit.  This
 273                  * would be set in readpage for sparse pages and here we would
 274                  * not need to mark dirty any pages which have this bit set.
 275                  * The only caveat is that we have to clear the bit everywhere
 276                  * where we allocate any clusters that lie in the page or that
 277                  * contain the page.
 278                  *
 279                  * TODO: An even greater optimization would be for us to only
 280                  * call readpage() on pages which are not in sparse regions as
 281                  * determined from the runlist.  This would greatly reduce the
 282                  * number of pages we read and make dirty in the case of sparse
 283                  * files.
 284                  */
 285                 balance_dirty_pages_ratelimited(mapping);
 286                 cond_resched();
 287         } while (++index < end_index);
 288         read_lock_irqsave(&ni->size_lock, flags);
 289         BUG_ON(ni->initialized_size != new_init_size);
 290         read_unlock_irqrestore(&ni->size_lock, flags);
 291         /* Now bring in sync the initialized_size in the mft record. */
 292         m = map_mft_record(base_ni);
 293         if (IS_ERR(m)) {
 294                 err = PTR_ERR(m);
 295                 m = NULL;
 296                 goto init_err_out;
 297         }
 298         ctx = ntfs_attr_get_search_ctx(base_ni, m);
 299         if (unlikely(!ctx)) {
 300                 err = -ENOMEM;
 301                 goto init_err_out;
 302         }
 303         err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
 304                         CASE_SENSITIVE, 0, NULL, 0, ctx);
 305         if (unlikely(err)) {
 306                 if (err == -ENOENT)
 307                         err = -EIO;
 308                 goto init_err_out;
 309         }
 310         m = ctx->mrec;
 311         a = ctx->attr;
 312         BUG_ON(!a->non_resident);
 313         a->data.non_resident.initialized_size = cpu_to_sle64(new_init_size);
 314 done:
 315         flush_dcache_mft_record_page(ctx->ntfs_ino);
 316         mark_mft_record_dirty(ctx->ntfs_ino);
 317         if (ctx)
 318                 ntfs_attr_put_search_ctx(ctx);
 319         if (m)
 320                 unmap_mft_record(base_ni);
 321         ntfs_debug("Done, initialized_size 0x%llx, i_size 0x%llx.",
 322                         (unsigned long long)new_init_size, i_size_read(vi));
 323         return 0;
 324 init_err_out:
 325         write_lock_irqsave(&ni->size_lock, flags);
 326         ni->initialized_size = old_init_size;
 327         write_unlock_irqrestore(&ni->size_lock, flags);
 328 err_out:
 329         if (ctx)
 330                 ntfs_attr_put_search_ctx(ctx);
 331         if (m)
 332                 unmap_mft_record(base_ni);
 333         ntfs_debug("Failed.  Returning error code %i.", err);
 334         return err;
 335 }
 336
 337 /**
 338  * ntfs_fault_in_pages_readable -
 339  *
 340  * Fault a number of userspace pages into pagetables.
 341  *
 342  * Unlike include/linux/pagemap.h::fault_in_pages_readable(), this one copes
 343  * with more than two userspace pages as well as handling the single page case
 344  * elegantly.
 345  *
 346  * If you find this difficult to understand, then think of the while loop being
 347  * the following code, except that we do without the integer variable ret:
 348  *
 349  *      do {
 350  *              ret = __get_user(c, uaddr);
 351  *              uaddr += PAGE_SIZE;
 352  *      } while (!ret && uaddr < end);
 353  *
 354  * Note, the final __get_user() may well run out-of-bounds of the user buffer,
 355  * but _not_ out-of-bounds of the page the user buffer belongs to, and since
 356  * this is only a read and not a write, and since it is still in the same page,
 357  * it should not matter and this makes the code much simpler.
 358  */
 359 static inline void ntfs_fault_in_pages_readable(const char __user *uaddr,
 360                 int bytes)
 361 {
 362         const char __user *end;
 363         volatile char c;
 364
 365         /* Set @end to the first byte outside the last page we care about. */
 366         end = (const char __user*)PAGE_ALIGN((ptrdiff_t __user)uaddr + bytes);
 367
 368         while (!__get_user(c, uaddr) && (uaddr += PAGE_SIZE, uaddr < end))
 369                 ;
 370 }
 371
 372 /**
 373  * ntfs_fault_in_pages_readable_iovec -
 374  *
 375  * Same as ntfs_fault_in_pages_readable() but operates on an array of iovecs.
 376  */
 377 static inline void ntfs_fault_in_pages_readable_iovec(const struct iovec *iov,
 378                 size_t iov_ofs, int bytes)
 379 {
 380         do {
 381                 const char __user *buf;
 382                 unsigned len;
 383
 384                 buf = iov->iov_base + iov_ofs;
 385                 len = iov->iov_len - iov_ofs;
 386                 if (len > bytes)
 387                         len = bytes;
 388                 ntfs_fault_in_pages_readable(buf, len);
 389                 bytes -= len;
 390                 iov++;
 391                 iov_ofs = 0;
 392         } while (bytes);
 393 }
 394
 395 /**
 396  * __ntfs_grab_cache_pages - obtain a number of locked pages
 397  * @mapping:    address space mapping from which to obtain page cache pages
 398  * @index:      starting index in @mapping at which to begin obtaining pages
 399  * @nr_pages:   number of page cache pages to obtain
 400  * @pages:      array of pages in which to return the obtained page cache pages
 401  * @cached_page: allocated but as yet unused page
 402  * @lru_pvec:   lru-buffering pagevec of caller
 403  *
 404  * Obtain @nr_pages locked page cache pages from the mapping @maping and
 405  * starting at index @index.
 406  *
 407  * If a page is newly created, increment its refcount and add it to the
 408  * caller's lru-buffering pagevec @lru_pvec.
 409  *
 410  * This is the same as mm/filemap.c::__grab_cache_page(), except that @nr_pages
 411  * are obtained at once instead of just one page and that 0 is returned on
 412  * success and -errno on error.
 413  *
 414  * Note, the page locks are obtained in ascending page index order.
 415  */
 416 static inline int __ntfs_grab_cache_pages(struct address_space *mapping,
 417                 pgoff_t index, const unsigned nr_pages, struct page **pages,
 418                 struct page **cached_page, struct pagevec *lru_pvec)
 419 {
 420         int err, nr;
 421
 422         BUG_ON(!nr_pages);
 423         err = nr = 0;
 424         do {
 425                 pages[nr] = find_lock_page(mapping, index);
 426                 if (!pages[nr]) {
 427                         if (!*cached_page) {
 428                                 *cached_page = page_cache_alloc(mapping);
 429                                 if (unlikely(!*cached_page)) {
 430                                         err = -ENOMEM;
 431                                         goto err_out;
 432                                 }
 433                         }
 434                         err = add_to_page_cache(*cached_page, mapping, index,
 435                                         GFP_KERNEL);
 436                         if (unlikely(err)) {
 437                                 if (err == -EEXIST)
 438                                         continue;
 439                                 goto err_out;
 440                         }
 441                         pages[nr] = *cached_page;
 442                         page_cache_get(*cached_page);
 443                         if (unlikely(!pagevec_add(lru_pvec, *cached_page)))
 444                                 __pagevec_lru_add(lru_pvec);
 445                         *cached_page = NULL;
 446                 }
 447                 index++;
 448                 nr++;
 449         } while (nr < nr_pages);
 450 out:
 451         return err;
 452 err_out:
 453         while (nr > 0) {
 454                 unlock_page(pages[--nr]);
 455                 page_cache_release(pages[nr]);
 456         }
 457         goto out;
 458 }
 459
 460 static inline int ntfs_submit_bh_for_read(struct buffer_head *bh)
 461 {
 462         lock_buffer(bh);
 463         get_bh(bh);
 464         bh->b_end_io = end_buffer_read_sync;
 465         return submit_bh(READ, bh);
 466 }
 467
 468 /**
 469  * ntfs_prepare_pages_for_non_resident_write - prepare pages for receiving data
 470  * @pages:      array of destination pages
 471  * @nr_pages:   number of pages in @pages
 472  * @pos:        byte position in file at which the write begins
 473  * @bytes:      number of bytes to be written
 474  *
 475  * This is called for non-resident attributes from ntfs_file_buffered_write()
 476  * with i_mutex held on the inode (@pages[0]->mapping->host).  There are
 477  * @nr_pages pages in @pages which are locked but not kmap()ped.  The source
 478  * data has not yet been copied into the @pages.
 479  *
 480  * Need to fill any holes with actual clusters, allocate buffers if necessary,
 481  * ensure all the buffers are mapped, and bring uptodate any buffers that are
 482  * only partially being written to.
 483  *
 484  * If @nr_pages is greater than one, we are guaranteed that the cluster size is
 485  * greater than PAGE_CACHE_SIZE, that all pages in @pages are entirely inside
 486  * the same cluster and that they are the entirety of that cluster, and that
 487  * the cluster is sparse, i.e. we need to allocate a cluster to fill the hole.
 488  *
 489  * i_size is not to be modified yet.
 490  *
 491  * Return 0 on success or -errno on error.
 492  */
 493 static int ntfs_prepare_pages_for_non_resident_write(struct page **pages,
 494                 unsigned nr_pages, s64 pos, size_t bytes)
 495 {
 496         VCN vcn, highest_vcn = 0, cpos, cend, bh_cpos, bh_cend;
 497         LCN lcn;
 498         s64 bh_pos, vcn_len, end, initialized_size;
 499         sector_t lcn_block;
 500         struct page *page;
 501         struct inode *vi;
 502         ntfs_inode *ni, *base_ni = NULL;
 503         ntfs_volume *vol;
 504         runlist_element *rl, *rl2;
 505         struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
 506         ntfs_attr_search_ctx *ctx = NULL;
 507         MFT_RECORD *m = NULL;
 508         ATTR_RECORD *a = NULL;
 509         unsigned long flags;
 510         u32 attr_rec_len = 0;
 511         unsigned blocksize, u;
 512         int err, mp_size;
 513         BOOL rl_write_locked, was_hole, is_retry;
 514         unsigned char blocksize_bits;
 515         struct {
 516                 u8 runlist_merged:1;
 517                 u8 mft_attr_mapped:1;
 518                 u8 mp_rebuilt:1;
 519                 u8 attr_switched:1;
 520         } status = { 0, 0, 0, 0 };
 521
 522         BUG_ON(!nr_pages);
 523         BUG_ON(!pages);
 524         BUG_ON(!*pages);
 525         vi = pages[0]->mapping->host;
 526         ni = NTFS_I(vi);
 527         vol = ni->vol;
 528         ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, start page "
 529                         "index 0x%lx, nr_pages 0x%x, pos 0x%llx, bytes 0x%zx.",
 530                         vi->i_ino, ni->type, pages[0]->index, nr_pages,
 531                         (long long)pos, bytes);
 532         blocksize = vol->sb->s_blocksize;
 533         blocksize_bits = vol->sb->s_blocksize_bits;
 534         u = 0;
 535         do {
 536                 struct page *page = pages[u];
 537                 /*
 538                  * create_empty_buffers() will create uptodate/dirty buffers if
 539                  * the page is uptodate/dirty.
 540                  */
 541                 if (!page_has_buffers(page)) {
 542                         create_empty_buffers(page, blocksize, 0);
 543                         if (unlikely(!page_has_buffers(page)))
 544                                 return -ENOMEM;
 545                 }
 546         } while (++u < nr_pages);
 547         rl_write_locked = FALSE;
 548         rl = NULL;
 549         err = 0;
 550         vcn = lcn = -1;
 551         vcn_len = 0;
 552         lcn_block = -1;
 553         was_hole = FALSE;
 554         cpos = pos >> vol->cluster_size_bits;
 555         end = pos + bytes;
 556         cend = (end + vol->cluster_size - 1) >> vol->cluster_size_bits;
 557         /*
 558          * Loop over each page and for each page over each buffer.  Use goto to
 559          * reduce indentation.
 560          */
 561         u = 0;
 562 do_next_page:
 563         page = pages[u];
 564         bh_pos = (s64)page->index << PAGE_CACHE_SHIFT;
 565         bh = head = page_buffers(page);
 566         do {
 567                 VCN cdelta;
 568                 s64 bh_end;
 569                 unsigned bh_cofs;
 570
 571                 /* Clear buffer_new on all buffers to reinitialise state. */
 572                 if (buffer_new(bh))
 573                         clear_buffer_new(bh);
 574                 bh_end = bh_pos + blocksize;
 575                 bh_cpos = bh_pos >> vol->cluster_size_bits;
 576                 bh_cofs = bh_pos & vol->cluster_size_mask;
 577                 if (buffer_mapped(bh)) {
 578                         /*
 579                          * The buffer is already mapped.  If it is uptodate,
 580                          * ignore it.
 581                          */
 582                         if (buffer_uptodate(bh))
 583                                 continue;
 584                         /*
 585                          * The buffer is not uptodate.  If the page is uptodate
 586                          * set the buffer uptodate and otherwise ignore it.
 587                          */
 588                         if (PageUptodate(page)) {
 589                                 set_buffer_uptodate(bh);
 590                                 continue;
 591                         }
 592                         /*
 593                          * Neither the page nor the buffer are uptodate.  If
 594                          * the buffer is only partially being written to, we
 595                          * need to read it in before the write, i.e. now.
 596                          */
 597                         if ((bh_pos < pos && bh_end > pos) ||
 598                                         (bh_pos < end && bh_end > end)) {
 599                                 /*
 600                                  * If the buffer is fully or partially within
 601                                  * the initialized size, do an actual read.
 602                                  * Otherwise, simply zero the buffer.
 603                                  */
 604                                 read_lock_irqsave(&ni->size_lock, flags);
 605                                 initialized_size = ni->initialized_size;
 606                                 read_unlock_irqrestore(&ni->size_lock, flags);
 607                                 if (bh_pos < initialized_size) {
 608                                         ntfs_submit_bh_for_read(bh);
 609                                         *wait_bh++ = bh;
 610                                 } else {
 611                                         u8 *kaddr = kmap_atomic(page, KM_USER0);
 612                                         memset(kaddr + bh_offset(bh), 0,
 613                                                         blocksize);
 614                                         kunmap_atomic(kaddr, KM_USER0);
 615                                         flush_dcache_page(page);
 616                                         set_buffer_uptodate(bh);
 617                                 }
 618                         }
 619                         continue;
 620                 }
 621                 /* Unmapped buffer.  Need to map it. */
 622                 bh->b_bdev = vol->sb->s_bdev;
 623                 /*
 624                  * If the current buffer is in the same clusters as the map
 625                  * cache, there is no need to check the runlist again.  The
 626                  * map cache is made up of @vcn, which is the first cached file
 627                  * cluster, @vcn_len which is the number of cached file
 628                  * clusters, @lcn is the device cluster corresponding to @vcn,
 629                  * and @lcn_block is the block number corresponding to @lcn.
 630                  */
 631                 cdelta = bh_cpos - vcn;
 632                 if (likely(!cdelta || (cdelta > 0 && cdelta < vcn_len))) {
 633 map_buffer_cached:
 634                         BUG_ON(lcn < 0);
 635                         bh->b_blocknr = lcn_block +
 636                                         (cdelta << (vol->cluster_size_bits -
 637                                         blocksize_bits)) +
 638                                         (bh_cofs >> blocksize_bits);
 639                         set_buffer_mapped(bh);
 640                         /*
 641                          * If the page is uptodate so is the buffer.  If the
 642                          * buffer is fully outside the write, we ignore it if
 643                          * it was already allocated and we mark it dirty so it
 644                          * gets written out if we allocated it.  On the other
 645                          * hand, if we allocated the buffer but we are not
 646                          * marking it dirty we set buffer_new so we can do
 647                          * error recovery.
 648                          */
 649                         if (PageUptodate(page)) {
 650                                 if (!buffer_uptodate(bh))
 651                                         set_buffer_uptodate(bh);
 652                                 if (unlikely(was_hole)) {
 653                                         /* We allocated the buffer. */
 654                                         unmap_underlying_metadata(bh->b_bdev,
 655                                                         bh->b_blocknr);
 656                                         if (bh_end <= pos || bh_pos >= end)
 657                                                 mark_buffer_dirty(bh);
 658                                         else
 659                                                 set_buffer_new(bh);
 660                                 }
 661                                 continue;
 662                         }
 663                         /* Page is _not_ uptodate. */
 664                         if (likely(!was_hole)) {
 665                                 /*
 666                                  * Buffer was already allocated.  If it is not
 667                                  * uptodate and is only partially being written
 668                                  * to, we need to read it in before the write,
 669                                  * i.e. now.
 670                                  */
 671                                 if (!buffer_uptodate(bh) && bh_pos < end &&
 672                                                 bh_end > pos &&
 673                                                 (bh_pos < pos ||
 674                                                 bh_end > end)) {
 675                                         /*
 676                                          * If the buffer is fully or partially
 677                                          * within the initialized size, do an
 678                                          * actual read.  Otherwise, simply zero
 679                                          * the buffer.
 680                                          */
 681                                         read_lock_irqsave(&ni->size_lock,
 682                                                         flags);
 683                                         initialized_size = ni->initialized_size;
 684                                         read_unlock_irqrestore(&ni->size_lock,
 685                                                         flags);
 686                                         if (bh_pos < initialized_size) {
 687                                                 ntfs_submit_bh_for_read(bh);
 688                                                 *wait_bh++ = bh;
 689                                         } else {
 690                                                 u8 *kaddr = kmap_atomic(page,
 691                                                                 KM_USER0);
 692                                                 memset(kaddr + bh_offset(bh),
 693                                                                 0, blocksize);
 694                                                 kunmap_atomic(kaddr, KM_USER0);
 695                                                 flush_dcache_page(page);
 696                                                 set_buffer_uptodate(bh);
 697                                         }
 698                                 }
 699                                 continue;
 700                         }
 701                         /* We allocated the buffer. */
 702                         unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
 703                         /*
 704                          * If the buffer is fully outside the write, zero it,
 705                          * set it uptodate, and mark it dirty so it gets
 706                          * written out.  If it is partially being written to,
 707                          * zero region surrounding the write but leave it to
 708                          * commit write to do anything else.  Finally, if the
 709                          * buffer is fully being overwritten, do nothing.
 710                          */
 711                         if (bh_end <= pos || bh_pos >= end) {
 712                                 if (!buffer_uptodate(bh)) {
 713                                         u8 *kaddr = kmap_atomic(page, KM_USER0);
 714                                         memset(kaddr + bh_offset(bh), 0,
 715                                                         blocksize);
 716                                         kunmap_atomic(kaddr, KM_USER0);
 717                                         flush_dcache_page(page);
 718                                         set_buffer_uptodate(bh);
 719                                 }
 720                                 mark_buffer_dirty(bh);
 721                                 continue;
 722                         }
 723                         set_buffer_new(bh);
 724                         if (!buffer_uptodate(bh) &&
 725                                         (bh_pos < pos || bh_end > end)) {
 726                                 u8 *kaddr;
 727                                 unsigned pofs;
 728
 729                                 kaddr = kmap_atomic(page, KM_USER0);
 730                                 if (bh_pos < pos) {
 731                                         pofs = bh_pos & ~PAGE_CACHE_MASK;
 732                                         memset(kaddr + pofs, 0, pos - bh_pos);
 733                                 }
 734                                 if (bh_end > end) {
 735                                         pofs = end & ~PAGE_CACHE_MASK;
 736                                         memset(kaddr + pofs, 0, bh_end - end);
 737                                 }
 738                                 kunmap_atomic(kaddr, KM_USER0);
 739                                 flush_dcache_page(page);
 740                         }
 741                         continue;
 742                 }
 743                 /*
 744                  * Slow path: this is the first buffer in the cluster.  If it
 745                  * is outside allocated size and is not uptodate, zero it and
 746                  * set it uptodate.
 747                  */
 748                 read_lock_irqsave(&ni->size_lock, flags);
 749                 initialized_size = ni->allocated_size;
 750                 read_unlock_irqrestore(&ni->size_lock, flags);
 751                 if (bh_pos > initialized_size) {
 752                         if (PageUptodate(page)) {
 753                                 if (!buffer_uptodate(bh))
 754                                         set_buffer_uptodate(bh);
 755                         } else if (!buffer_uptodate(bh)) {
 756                                 u8 *kaddr = kmap_atomic(page, KM_USER0);
 757                                 memset(kaddr + bh_offset(bh), 0, blocksize);
 758                                 kunmap_atomic(kaddr, KM_USER0);
 759                                 flush_dcache_page(page);
 760                                 set_buffer_uptodate(bh);
 761                         }
 762                         continue;
 763                 }
 764                 is_retry = FALSE;
 765                 if (!rl) {
 766                         down_read(&ni->runlist.lock);
 767 retry_remap:
 768                         rl = ni->runlist.rl;
 769                 }
 770                 if (likely(rl != NULL)) {
 771                         /* Seek to element containing target cluster. */
 772                         while (rl->length && rl[1].vcn <= bh_cpos)
 773                                 rl++;
 774                         lcn = ntfs_rl_vcn_to_lcn(rl, bh_cpos);
 775                         if (likely(lcn >= 0)) {
 776                                 /*
 777                                  * Successful remap, setup the map cache and
 778                                  * use that to deal with the buffer.
 779                                  */
 780                                 was_hole = FALSE;
 781                                 vcn = bh_cpos;
 782                                 vcn_len = rl[1].vcn - vcn;
 783                                 lcn_block = lcn << (vol->cluster_size_bits -
 784                                                 blocksize_bits);
 785                                 cdelta = 0;
 786                                 /*
 787                                  * If the number of remaining clusters touched
 788                                  * by the write is smaller or equal to the
 789                                  * number of cached clusters, unlock the
 790                                  * runlist as the map cache will be used from
 791                                  * now on.
 792                                  */
 793                                 if (likely(vcn + vcn_len >= cend)) {
 794                                         if (rl_write_locked) {
 795                                                 up_write(&ni->runlist.lock);
 796                                                 rl_write_locked = FALSE;
 797                                         } else
 798                                                 up_read(&ni->runlist.lock);
 799                                         rl = NULL;
 800                                 }
 801                                 goto map_buffer_cached;
 802                         }
 803                 } else
 804                         lcn = LCN_RL_NOT_MAPPED;
 805                 /*
 806                  * If it is not a hole and not out of bounds, the runlist is
 807                  * probably unmapped so try to map it now.
 808                  */
 809                 if (unlikely(lcn != LCN_HOLE && lcn != LCN_ENOENT)) {
 810                         if (likely(!is_retry && lcn == LCN_RL_NOT_MAPPED)) {
 811                                 /* Attempt to map runlist. */
 812                                 if (!rl_write_locked) {
 813                                         /*
 814                                          * We need the runlist locked for
 815                                          * writing, so if it is locked for
 816                                          * reading relock it now and retry in
 817                                          * case it changed whilst we dropped
 818                                          * the lock.
 819                                          */
 820                                         up_read(&ni->runlist.lock);
 821                                         down_write(&ni->runlist.lock);
 822                                         rl_write_locked = TRUE;
 823                                         goto retry_remap;
 824                                 }
 825                                 err = ntfs_map_runlist_nolock(ni, bh_cpos,
 826                                                 NULL);
 827                                 if (likely(!err)) {
 828                                         is_retry = TRUE;
 829                                         goto retry_remap;
 830                                 }
 831                                 /*
 832                                  * If @vcn is out of bounds, pretend @lcn is
 833                                  * LCN_ENOENT.  As long as the buffer is out
 834                                  * of bounds this will work fine.
 835                                  */
 836                                 if (err == -ENOENT) {
 837                                         lcn = LCN_ENOENT;
 838                                         err = 0;
 839                                         goto rl_not_mapped_enoent;
 840                                 }
 841                         } else
 842                                 err = -EIO;
 843                         /* Failed to map the buffer, even after retrying. */
 844                         bh->b_blocknr = -1;
 845                         ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
 846                                         "attribute type 0x%x, vcn 0x%llx, "
 847                                         "vcn offset 0x%x, because its "
 848                                         "location on disk could not be "
 849                                         "determined%s (error code %i).",
 850                                         ni->mft_no, ni->type,
 851                                         (unsigned long long)bh_cpos,
 852                                         (unsigned)bh_pos &
 853                                         vol->cluster_size_mask,
 854                                         is_retry ? " even after retrying" : "",
 855                                         err);
 856                         break;
 857                 }
 858 rl_not_mapped_enoent:
 859                 /*
 860                  * The buffer is in a hole or out of bounds.  We need to fill
 861                  * the hole, unless the buffer is in a cluster which is not
 862                  * touched by the write, in which case we just leave the buffer
 863                  * unmapped.  This can only happen when the cluster size is
 864                  * less than the page cache size.
 865                  */
 866                 if (unlikely(vol->cluster_size < PAGE_CACHE_SIZE)) {
 867                         bh_cend = (bh_end + vol->cluster_size - 1) >>
 868                                         vol->cluster_size_bits;
 869                         if ((bh_cend <= cpos || bh_cpos >= cend)) {
 870                                 bh->b_blocknr = -1;
 871                                 /*
 872                                  * If the buffer is uptodate we skip it.  If it
 873                                  * is not but the page is uptodate, we can set
 874                                  * the buffer uptodate.  If the page is not
 875                                  * uptodate, we can clear the buffer and set it
 876                                  * uptodate.  Whether this is worthwhile is
 877                                  * debatable and this could be removed.
 878                                  */
 879                                 if (PageUptodate(page)) {
 880                                         if (!buffer_uptodate(bh))
 881                                                 set_buffer_uptodate(bh);
 882                                 } else if (!buffer_uptodate(bh)) {
 883                                         u8 *kaddr = kmap_atomic(page, KM_USER0);
 884                                         memset(kaddr + bh_offset(bh), 0,
 885                                                         blocksize);
 886                                         kunmap_atomic(kaddr, KM_USER0);
 887                                         flush_dcache_page(page);
 888                                         set_buffer_uptodate(bh);
 889                                 }
 890                                 continue;
 891                         }
 892                 }
 893                 /*
 894                  * Out of bounds buffer is invalid if it was not really out of
 895                  * bounds.
 896                  */
 897                 BUG_ON(lcn != LCN_HOLE);
 898                 /*
 899                  * We need the runlist locked for writing, so if it is locked
 900                  * for reading relock it now and retry in case it changed
 901                  * whilst we dropped the lock.
 902                  */
 903                 BUG_ON(!rl);
 904                 if (!rl_write_locked) {
 905                         up_read(&ni->runlist.lock);
 906                         down_write(&ni->runlist.lock);
 907                         rl_write_locked = TRUE;
 908                         goto retry_remap;
 909                 }
 910                 /* Find the previous last allocated cluster. */
 911                 BUG_ON(rl->lcn != LCN_HOLE);
 912                 lcn = -1;
 913                 rl2 = rl;
 914                 while (--rl2 >= ni->runlist.rl) {
 915                         if (rl2->lcn >= 0) {
 916                                 lcn = rl2->lcn + rl2->length;
 917                                 break;
 918                         }
 919                 }
 920                 rl2 = ntfs_cluster_alloc(vol, bh_cpos, 1, lcn, DATA_ZONE,
 921                                 FALSE);
 922                 if (IS_ERR(rl2)) {
 923                         err = PTR_ERR(rl2);
 924                         ntfs_debug("Failed to allocate cluster, error code %i.",
 925                                         err);
 926                         break;
 927                 }
 928                 lcn = rl2->lcn;
 929                 rl = ntfs_runlists_merge(ni->runlist.rl, rl2);
 930                 if (IS_ERR(rl)) {
 931                         err = PTR_ERR(rl);
 932                         if (err != -ENOMEM)
 933                                 err = -EIO;
 934                         if (ntfs_cluster_free_from_rl(vol, rl2)) {
 935                                 ntfs_error(vol->sb, "Failed to release "
 936                                                 "allocated cluster in error "
 937                                                 "code path.  Run chkdsk to "
 938                                                 "recover the lost cluster.");
 939                                 NVolSetErrors(vol);
 940                         }
 941                         ntfs_free(rl2);
 942                         break;
 943                 }
 944                 ni->runlist.rl = rl;
 945                 status.runlist_merged = 1;
 946                 ntfs_debug("Allocated cluster, lcn 0x%llx.",
 947                                 (unsigned long long)lcn);
 948                 /* Map and lock the mft record and get the attribute record. */
 949                 if (!NInoAttr(ni))
 950                         base_ni = ni;
 951                 else
 952                         base_ni = ni->ext.base_ntfs_ino;
 953                 m = map_mft_record(base_ni);
 954                 if (IS_ERR(m)) {
 955                         err = PTR_ERR(m);
 956                         break;
 957                 }
 958                 ctx = ntfs_attr_get_search_ctx(base_ni, m);
 959                 if (unlikely(!ctx)) {
 960                         err = -ENOMEM;
 961                         unmap_mft_record(base_ni);
 962                         break;
 963                 }
 964                 status.mft_attr_mapped = 1;
 965                 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
 966                                 CASE_SENSITIVE, bh_cpos, NULL, 0, ctx);
 967                 if (unlikely(err)) {
 968                         if (err == -ENOENT)
 969                                 err = -EIO;
 970                         break;
 971                 }
 972                 m = ctx->mrec;
 973                 a = ctx->attr;
 974                 /*
 975                  * Find the runlist element with which the attribute extent
 976                  * starts.  Note, we cannot use the _attr_ version because we
 977                  * have mapped the mft record.  That is ok because we know the
 978                  * runlist fragment must be mapped already to have ever gotten
 979                  * here, so we can just use the _rl_ version.
 980                  */
 981                 vcn = sle64_to_cpu(a->data.non_resident.lowest_vcn);
 982                 rl2 = ntfs_rl_find_vcn_nolock(rl, vcn);
 983                 BUG_ON(!rl2);
 984                 BUG_ON(!rl2->length);
 985                 BUG_ON(rl2->lcn < LCN_HOLE);
 986                 highest_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
 987                 /*
 988                  * If @highest_vcn is zero, calculate the real highest_vcn
 989                  * (which can really be zero).
 990                  */
 991                 if (!highest_vcn)
 992                         highest_vcn = (sle64_to_cpu(
 993                                         a->data.non_resident.allocated_size) >>
 994                                         vol->cluster_size_bits) - 1;
 995                 /*
 996                  * Determine the size of the mapping pairs array for the new
 997                  * extent, i.e. the old extent with the hole filled.
 998                  */
 999                 mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, vcn,
1000                                 highest_vcn);
1001                 if (unlikely(mp_size <= 0)) {
1002                         if (!(err = mp_size))
1003                                 err = -EIO;
1004                         ntfs_debug("Failed to get size for mapping pairs "
1005                                         "array, error code %i.", err);
1006                         break;
1007                 }
1008                 /*
1009                  * Resize the attribute record to fit the new mapping pairs
1010                  * array.
1011                  */
1012                 attr_rec_len = le32_to_cpu(a->length);
1013                 err = ntfs_attr_record_resize(m, a, mp_size + le16_to_cpu(
1014                                 a->data.non_resident.mapping_pairs_offset));
1015                 if (unlikely(err)) {
1016                         BUG_ON(err != -ENOSPC);
1017                         // TODO: Deal with this by using the current attribute
1018                         // and fill it with as much of the mapping pairs
1019                         // array as possible.  Then loop over each attribute
1020                         // extent rewriting the mapping pairs arrays as we go
1021                         // along and if when we reach the end we have not
1022                         // enough space, try to resize the last attribute
1023                         // extent and if even that fails, add a new attribute
1024                         // extent.
1025                         // We could also try to resize at each step in the hope
1026                         // that we will not need to rewrite every single extent.
1027                         // Note, we may need to decompress some extents to fill
1028                         // the runlist as we are walking the extents...
1029                         ntfs_error(vol->sb, "Not enough space in the mft "
1030                                         "record for the extended attribute "
1031                                         "record.  This case is not "
1032                                         "implemented yet.");
1033                         err = -EOPNOTSUPP;
1034                         break ;
1035                 }
1036                 status.mp_rebuilt = 1;
1037                 /*
1038                  * Generate the mapping pairs array directly into the attribute
1039                  * record.
1040                  */
1041                 err = ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
1042                                 a->data.non_resident.mapping_pairs_offset),
1043                                 mp_size, rl2, vcn, highest_vcn, NULL);
1044                 if (unlikely(err)) {
1045                         ntfs_error(vol->sb, "Cannot fill hole in inode 0x%lx, "
1046                                         "attribute type 0x%x, because building "
1047                                         "the mapping pairs failed with error "
1048                                         "code %i.", vi->i_ino,
1049                                         (unsigned)le32_to_cpu(ni->type), err);
1050                         err = -EIO;
1051                         break;
1052                 }
1053                 /* Update the highest_vcn but only if it was not set. */
1054                 if (unlikely(!a->data.non_resident.highest_vcn))
1055                         a->data.non_resident.highest_vcn =
1056                                         cpu_to_sle64(highest_vcn);
1057                 /*
1058                  * If the attribute is sparse/compressed, update the compressed
1059                  * size in the ntfs_inode structure and the attribute record.
1060                  */
1061                 if (likely(NInoSparse(ni) || NInoCompressed(ni))) {
1062                         /*
1063                          * If we are not in the first attribute extent, switch
1064                          * to it, but first ensure the changes will make it to
1065                          * disk later.
1066                          */
1067                         if (a->data.non_resident.lowest_vcn) {
1068                                 flush_dcache_mft_record_page(ctx->ntfs_ino);
1069                                 mark_mft_record_dirty(ctx->ntfs_ino);
1070                                 ntfs_attr_reinit_search_ctx(ctx);
1071                                 err = ntfs_attr_lookup(ni->type, ni->name,
1072                                                 ni->name_len, CASE_SENSITIVE,
1073                                                 0, NULL, 0, ctx);
1074                                 if (unlikely(err)) {
1075                                         status.attr_switched = 1;
1076                                         break;
1077                                 }
1078                                 /* @m is not used any more so do not set it. */
1079                                 a = ctx->attr;
1080                         }
1081                         write_lock_irqsave(&ni->size_lock, flags);
1082                         ni->itype.compressed.size += vol->cluster_size;
1083                         a->data.non_resident.compressed_size =
1084                                         cpu_to_sle64(ni->itype.compressed.size);
1085                         write_unlock_irqrestore(&ni->size_lock, flags);
1086                 }
1087                 /* Ensure the changes make it to disk. */
1088                 flush_dcache_mft_record_page(ctx->ntfs_ino);
1089                 mark_mft_record_dirty(ctx->ntfs_ino);
1090                 ntfs_attr_put_search_ctx(ctx);
1091                 unmap_mft_record(base_ni);
1092                 /* Successfully filled the hole. */
1093                 status.runlist_merged = 0;
1094                 status.mft_attr_mapped = 0;
1095                 status.mp_rebuilt = 0;
1096                 /* Setup the map cache and use that to deal with the buffer. */
1097                 was_hole = TRUE;
1098                 vcn = bh_cpos;
1099                 vcn_len = 1;
1100                 lcn_block = lcn << (vol->cluster_size_bits - blocksize_bits);
1101                 cdelta = 0;
1102                 /*
1103                  * If the number of remaining clusters in the @pages is smaller
1104                  * or equal to the number of cached clusters, unlock the
1105                  * runlist as the map cache will be used from now on.
1106                  */
1107                 if (likely(vcn + vcn_len >= cend)) {
1108                         up_write(&ni->runlist.lock);
1109                         rl_write_locked = FALSE;
1110                         rl = NULL;
1111                 }
1112                 goto map_buffer_cached;
1113         } while (bh_pos += blocksize, (bh = bh->b_this_page) != head);
1114         /* If there are no errors, do the next page. */
1115         if (likely(!err && ++u < nr_pages))
1116                 goto do_next_page;
1117         /* If there are no errors, release the runlist lock if we took it. */
1118         if (likely(!err)) {
1119                 if (unlikely(rl_write_locked)) {
1120                         up_write(&ni->runlist.lock);
1121                         rl_write_locked = FALSE;
1122                 } else if (unlikely(rl))
1123                         up_read(&ni->runlist.lock);
1124                 rl = NULL;
1125         }
1126         /* If we issued read requests, let them complete. */
1127         read_lock_irqsave(&ni->size_lock, flags);
1128         initialized_size = ni->initialized_size;
1129         read_unlock_irqrestore(&ni->size_lock, flags);
1130         while (wait_bh > wait) {
1131                 bh = *--wait_bh;
1132                 wait_on_buffer(bh);
1133                 if (likely(buffer_uptodate(bh))) {
1134                         page = bh->b_page;
1135                         bh_pos = ((s64)page->index << PAGE_CACHE_SHIFT) +
1136                                         bh_offset(bh);
1137                         /*
1138                          * If the buffer overflows the initialized size, need
1139                          * to zero the overflowing region.
1140                          */
1141                         if (unlikely(bh_pos + blocksize > initialized_size)) {
1142                                 u8 *kaddr;
1143                                 int ofs = 0;
1144
1145                                 if (likely(bh_pos < initialized_size))
1146                                         ofs = initialized_size - bh_pos;
1147                                 kaddr = kmap_atomic(page, KM_USER0);
1148                                 memset(kaddr + bh_offset(bh) + ofs, 0,
1149                                                 blocksize - ofs);
1150                                 kunmap_atomic(kaddr, KM_USER0);
1151                                 flush_dcache_page(page);
1152                         }
1153                 } else /* if (unlikely(!buffer_uptodate(bh))) */
1154                         err = -EIO;
1155         }
1156         if (likely(!err)) {
1157                 /* Clear buffer_new on all buffers. */
1158                 u = 0;
1159                 do {
1160                         bh = head = page_buffers(pages[u]);
1161                         do {
1162                                 if (buffer_new(bh))
1163                                         clear_buffer_new(bh);
1164                         } while ((bh = bh->b_this_page) != head);
1165                 } while (++u < nr_pages);
1166                 ntfs_debug("Done.");
1167                 return err;
1168         }
1169         if (status.attr_switched) {
1170                 /* Get back to the attribute extent we modified. */
1171                 ntfs_attr_reinit_search_ctx(ctx);
1172                 if (ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1173                                 CASE_SENSITIVE, bh_cpos, NULL, 0, ctx)) {
1174                         ntfs_error(vol->sb, "Failed to find required "
1175                                         "attribute extent of attribute in "
1176                                         "error code path.  Run chkdsk to "
1177                                         "recover.");
1178                         write_lock_irqsave(&ni->size_lock, flags);
1179                         ni->itype.compressed.size += vol->cluster_size;
1180                         write_unlock_irqrestore(&ni->size_lock, flags);
1181                         flush_dcache_mft_record_page(ctx->ntfs_ino);
1182                         mark_mft_record_dirty(ctx->ntfs_ino);
1183                         /*
1184                          * The only thing that is now wrong is the compressed
1185                          * size of the base attribute extent which chkdsk
1186                          * should be able to fix.
1187                          */
1188                         NVolSetErrors(vol);
1189                 } else {
1190                         m = ctx->mrec;
1191                         a = ctx->attr;
1192                         status.attr_switched = 0;
1193                 }
1194         }
1195         /*
1196          * If the runlist has been modified, need to restore it by punching a
1197          * hole into it and we then need to deallocate the on-disk cluster as
1198          * well.  Note, we only modify the runlist if we are able to generate a
1199          * new mapping pairs array, i.e. only when the mapped attribute extent
1200          * is not switched.
1201          */
1202         if (status.runlist_merged && !status.attr_switched) {
1203                 BUG_ON(!rl_write_locked);
1204                 /* Make the file cluster we allocated sparse in the runlist. */
1205                 if (ntfs_rl_punch_nolock(vol, &ni->runlist, bh_cpos, 1)) {
1206                         ntfs_error(vol->sb, "Failed to punch hole into "
1207                                         "attribute runlist in error code "
1208                                         "path.  Run chkdsk to recover the "
1209                                         "lost cluster.");
1210                         make_bad_inode(vi);
1211                         make_bad_inode(VFS_I(base_ni));
1212                         NVolSetErrors(vol);
1213                 } else /* if (success) */ {
1214                         status.runlist_merged = 0;
1215                         /*
1216                          * Deallocate the on-disk cluster we allocated but only
1217                          * if we succeeded in punching its vcn out of the
1218                          * runlist.
1219                          */
1220                         down_write(&vol->lcnbmp_lock);
1221                         if (ntfs_bitmap_clear_bit(vol->lcnbmp_ino, lcn)) {
1222                                 ntfs_error(vol->sb, "Failed to release "
1223                                                 "allocated cluster in error "
1224                                                 "code path.  Run chkdsk to "
1225                                                 "recover the lost cluster.");
1226                                 NVolSetErrors(vol);
1227                         }
1228                         up_write(&vol->lcnbmp_lock);
1229                 }
1230         }
1231         /*
1232          * Resize the attribute record to its old size and rebuild the mapping
1233          * pairs array.  Note, we only can do this if the runlist has been
1234          * restored to its old state which also implies that the mapped
1235          * attribute extent is not switched.
1236          */
1237         if (status.mp_rebuilt && !status.runlist_merged) {
1238                 if (ntfs_attr_record_resize(m, a, attr_rec_len)) {
1239                         ntfs_error(vol->sb, "Failed to restore attribute "
1240                                         "record in error code path.  Run "
1241                                         "chkdsk to recover.");
1242                         make_bad_inode(vi);
1243                         make_bad_inode(VFS_I(base_ni));
1244                         NVolSetErrors(vol);
1245                 } else /* if (success) */ {
1246                         if (ntfs_mapping_pairs_build(vol, (u8*)a +
1247                                         le16_to_cpu(a->data.non_resident.
1248                                         mapping_pairs_offset), attr_rec_len -
1249                                         le16_to_cpu(a->data.non_resident.
1250                                         mapping_pairs_offset), ni->runlist.rl,
1251                                         vcn, highest_vcn, NULL)) {
1252                                 ntfs_error(vol->sb, "Failed to restore "
1253                                                 "mapping pairs array in error "
1254                                                 "code path.  Run chkdsk to "
1255                                                 "recover.");
1256                                 make_bad_inode(vi);
1257                                 make_bad_inode(VFS_I(base_ni));
1258                                 NVolSetErrors(vol);
1259                         }
1260                         flush_dcache_mft_record_page(ctx->ntfs_ino);
1261                         mark_mft_record_dirty(ctx->ntfs_ino);
1262                 }
1263         }
1264         /* Release the mft record and the attribute. */
1265         if (status.mft_attr_mapped) {
1266                 ntfs_attr_put_search_ctx(ctx);
1267                 unmap_mft_record(base_ni);
1268         }
1269         /* Release the runlist lock. */
1270         if (rl_write_locked)
1271                 up_write(&ni->runlist.lock);
1272         else if (rl)
1273                 up_read(&ni->runlist.lock);
1274         /*
1275          * Zero out any newly allocated blocks to avoid exposing stale data.
1276          * If BH_New is set, we know that the block was newly allocated above
1277          * and that it has not been fully zeroed and marked dirty yet.
1278          */
1279         nr_pages = u;
1280         u = 0;
1281         end = bh_cpos << vol->cluster_size_bits;
1282         do {
1283                 page = pages[u];
1284                 bh = head = page_buffers(page);
1285                 do {
1286                         if (u == nr_pages &&
1287                                         ((s64)page->index << PAGE_CACHE_SHIFT) +
1288                                         bh_offset(bh) >= end)
1289                                 break;
1290                         if (!buffer_new(bh))
1291                                 continue;
1292                         clear_buffer_new(bh);
1293                         if (!buffer_uptodate(bh)) {
1294                                 if (PageUptodate(page))
1295                                         set_buffer_uptodate(bh);
1296                                 else {
1297                                         u8 *kaddr = kmap_atomic(page, KM_USER0);
1298                                         memset(kaddr + bh_offset(bh), 0,
1299                                                         blocksize);
1300                                         kunmap_atomic(kaddr, KM_USER0);
1301                                         flush_dcache_page(page);
1302                                         set_buffer_uptodate(bh);
1303                                 }
1304                         }
1305                         mark_buffer_dirty(bh);
1306                 } while ((bh = bh->b_this_page) != head);
1307         } while (++u <= nr_pages);
1308         ntfs_error(vol->sb, "Failed.  Returning error code %i.", err);
1309         return err;
1310 }
1311
1312 /*
1313  * Copy as much as we can into the pages and return the number of bytes which
1314  * were sucessfully copied.  If a fault is encountered then clear the pages
1315  * out to (ofs + bytes) and return the number of bytes which were copied.
1316  */
1317 static inline size_t ntfs_copy_from_user(struct page **pages,
1318                 unsigned nr_pages, unsigned ofs, const char __user *buf,
1319                 size_t bytes)
1320 {
1321         struct page **last_page = pages + nr_pages;
1322         char *kaddr;
1323         size_t total = 0;
1324         unsigned len;
1325         int left;
1326
1327         do {
1328                 len = PAGE_CACHE_SIZE - ofs;
1329                 if (len > bytes)
1330                         len = bytes;
1331                 kaddr = kmap_atomic(*pages, KM_USER0);
1332                 left = __copy_from_user_inatomic(kaddr + ofs, buf, len);
1333                 kunmap_atomic(kaddr, KM_USER0);
1334                 if (unlikely(left)) {
1335                         /* Do it the slow way. */
1336                         kaddr = kmap(*pages);
1337                         left = __copy_from_user(kaddr + ofs, buf, len);
1338                         kunmap(*pages);
1339                         if (unlikely(left))
1340                                 goto err_out;
1341                 }
1342                 total += len;
1343                 bytes -= len;
1344                 if (!bytes)
1345                         break;
1346                 buf += len;
1347                 ofs = 0;
1348         } while (++pages < last_page);
1349 out:
1350         return total;
1351 err_out:
1352         total += len - left;
1353         /* Zero the rest of the target like __copy_from_user(). */
1354         while (++pages < last_page) {
1355                 bytes -= len;
1356                 if (!bytes)
1357                         break;
1358                 len = PAGE_CACHE_SIZE;
1359                 if (len > bytes)
1360                         len = bytes;
1361                 kaddr = kmap_atomic(*pages, KM_USER0);
1362                 memset(kaddr, 0, len);
1363                 kunmap_atomic(kaddr, KM_USER0);
1364         }
1365         goto out;
1366 }
1367
1368 static size_t __ntfs_copy_from_user_iovec(char *vaddr,
1369                 const struct iovec *iov, size_t iov_ofs, size_t bytes)
1370 {
1371         size_t total = 0;
1372
1373         while (1) {
1374                 const char __user *buf = iov->iov_base + iov_ofs;
1375                 unsigned len;
1376                 size_t left;
1377
1378                 len = iov->iov_len - iov_ofs;
1379                 if (len > bytes)
1380                         len = bytes;
1381                 left = __copy_from_user_inatomic(vaddr, buf, len);
1382                 total += len;
1383                 bytes -= len;
1384                 vaddr += len;
1385                 if (unlikely(left)) {
1386                         /*
1387                          * Zero the rest of the target like __copy_from_user().
1388                          */
1389                         memset(vaddr, 0, bytes);
1390                         total -= left;
1391                         break;
1392                 }
1393                 if (!bytes)
1394                         break;
1395                 iov++;
1396                 iov_ofs = 0;
1397         }
1398         return total;
1399 }
1400
1401 static inline void ntfs_set_next_iovec(const struct iovec **iovp,
1402                 size_t *iov_ofsp, size_t bytes)
1403 {
1404         const struct iovec *iov = *iovp;
1405         size_t iov_ofs = *iov_ofsp;
1406
1407         while (bytes) {
1408                 unsigned len;
1409
1410                 len = iov->iov_len - iov_ofs;
1411                 if (len > bytes)
1412                         len = bytes;
1413                 bytes -= len;
1414                 iov_ofs += len;
1415                 if (iov->iov_len == iov_ofs) {
1416                         iov++;
1417                         iov_ofs = 0;
1418                 }
1419         }
1420         *iovp = iov;
1421         *iov_ofsp = iov_ofs;
1422 }
1423
1424 /*
1425  * This has the same side-effects and return value as ntfs_copy_from_user().
1426  * The difference is that on a fault we need to memset the remainder of the
1427  * pages (out to offset + bytes), to emulate ntfs_copy_from_user()'s
1428  * single-segment behaviour.
1429  *
1430  * We call the same helper (__ntfs_copy_from_user_iovec()) both when atomic and
1431  * when not atomic.  This is ok because __ntfs_copy_from_user_iovec() calls
1432  * __copy_from_user_inatomic() and it is ok to call this when non-atomic.  In
1433  * fact, the only difference between __copy_from_user_inatomic() and
1434  * __copy_from_user() is that the latter calls might_sleep().  And on many
1435  * architectures __copy_from_user_inatomic() is just defined to
1436  * __copy_from_user() so it makes no difference at all on those architectures.
1437  */
1438 static inline size_t ntfs_copy_from_user_iovec(struct page **pages,
1439                 unsigned nr_pages, unsigned ofs, const struct iovec **iov,
1440                 size_t *iov_ofs, size_t bytes)
1441 {
1442         struct page **last_page = pages + nr_pages;
1443         char *kaddr;
1444         size_t copied, len, total = 0;
1445
1446         do {
1447                 len = PAGE_CACHE_SIZE - ofs;
1448                 if (len > bytes)
1449                         len = bytes;
1450                 kaddr = kmap_atomic(*pages, KM_USER0);
1451                 copied = __ntfs_copy_from_user_iovec(kaddr + ofs,
1452                                 *iov, *iov_ofs, len);
1453                 kunmap_atomic(kaddr, KM_USER0);
1454                 if (unlikely(copied != len)) {
1455                         /* Do it the slow way. */
1456                         kaddr = kmap(*pages);
1457                         copied = __ntfs_copy_from_user_iovec(kaddr + ofs,
1458                                         *iov, *iov_ofs, len);
1459                         kunmap(*pages);
1460                         if (unlikely(copied != len))
1461                                 goto err_out;
1462                 }
1463                 total += len;
1464                 bytes -= len;
1465                 if (!bytes)
1466                         break;
1467                 ntfs_set_next_iovec(iov, iov_ofs, len);
1468                 ofs = 0;
1469         } while (++pages < last_page);
1470 out:
1471         return total;
1472 err_out:
1473         total += copied;
1474         /* Zero the rest of the target like __copy_from_user(). */
1475         while (++pages < last_page) {
1476                 bytes -= len;
1477                 if (!bytes)
1478                         break;
1479                 len = PAGE_CACHE_SIZE;
1480                 if (len > bytes)
1481                         len = bytes;
1482                 kaddr = kmap_atomic(*pages, KM_USER0);
1483                 memset(kaddr, 0, len);
1484                 kunmap_atomic(kaddr, KM_USER0);
1485         }
1486         goto out;
1487 }
1488
1489 static inline void ntfs_flush_dcache_pages(struct page **pages,
1490                 unsigned nr_pages)
1491 {
1492         BUG_ON(!nr_pages);
1493         do {
1494                 /*
1495                  * Warning: Do not do the decrement at the same time as the
1496                  * call because flush_dcache_page() is a NULL macro on i386
1497                  * and hence the decrement never happens.
1498                  */
1499                 flush_dcache_page(pages[nr_pages]);
1500         } while (--nr_pages > 0);
1501 }
1502
1503 /**
1504  * ntfs_commit_pages_after_non_resident_write - commit the received data
1505  * @pages:      array of destination pages
1506  * @nr_pages:   number of pages in @pages
1507  * @pos:        byte position in file at which the write begins
1508  * @bytes:      number of bytes to be written
1509  *
1510  * See description of ntfs_commit_pages_after_write(), below.
1511  */
1512 static inline int ntfs_commit_pages_after_non_resident_write(
1513                 struct page **pages, const unsigned nr_pages,
1514                 s64 pos, size_t bytes)
1515 {
1516         s64 end, initialized_size;
1517         struct inode *vi;
1518         ntfs_inode *ni, *base_ni;
1519         struct buffer_head *bh, *head;
1520         ntfs_attr_search_ctx *ctx;
1521         MFT_RECORD *m;
1522         ATTR_RECORD *a;
1523         unsigned long flags;
1524         unsigned blocksize, u;
1525         int err;
1526
1527         vi = pages[0]->mapping->host;
1528         ni = NTFS_I(vi);
1529         blocksize = vi->i_sb->s_blocksize;
1530         end = pos + bytes;
1531         u = 0;
1532         do {
1533                 s64 bh_pos;
1534                 struct page *page;
1535                 BOOL partial;
1536
1537                 page = pages[u];
1538                 bh_pos = (s64)page->index << PAGE_CACHE_SHIFT;
1539                 bh = head = page_buffers(page);
1540                 partial = FALSE;
1541                 do {
1542                         s64 bh_end;
1543
1544                         bh_end = bh_pos + blocksize;
1545                         if (bh_end <= pos || bh_pos >= end) {
1546                                 if (!buffer_uptodate(bh))
1547                                         partial = TRUE;
1548                         } else {
1549                                 set_buffer_uptodate(bh);
1550                                 mark_buffer_dirty(bh);
1551                         }
1552                 } while (bh_pos += blocksize, (bh = bh->b_this_page) != head);
1553                 /*
1554                  * If all buffers are now uptodate but the page is not, set the
1555                  * page uptodate.
1556                  */
1557                 if (!partial && !PageUptodate(page))
1558                         SetPageUptodate(page);
1559         } while (++u < nr_pages);
1560         /*
1561          * Finally, if we do not need to update initialized_size or i_size we
1562          * are finished.
1563          */
1564         read_lock_irqsave(&ni->size_lock, flags);
1565         initialized_size = ni->initialized_size;
1566         read_unlock_irqrestore(&ni->size_lock, flags);
1567         if (end <= initialized_size) {
1568                 ntfs_debug("Done.");
1569                 return 0;
1570         }
1571         /*
1572          * Update initialized_size/i_size as appropriate, both in the inode and
1573          * the mft record.
1574          */
1575         if (!NInoAttr(ni))
1576                 base_ni = ni;
1577         else
1578                 base_ni = ni->ext.base_ntfs_ino;
1579         /* Map, pin, and lock the mft record. */
1580         m = map_mft_record(base_ni);
1581         if (IS_ERR(m)) {
1582                 err = PTR_ERR(m);
1583                 m = NULL;
1584                 ctx = NULL;
1585                 goto err_out;
1586         }
1587         BUG_ON(!NInoNonResident(ni));
1588         ctx = ntfs_attr_get_search_ctx(base_ni, m);
1589         if (unlikely(!ctx)) {
1590                 err = -ENOMEM;
1591                 goto err_out;
1592         }
1593         err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1594                         CASE_SENSITIVE, 0, NULL, 0, ctx);
1595         if (unlikely(err)) {
1596                 if (err == -ENOENT)
1597                         err = -EIO;
1598                 goto err_out;
1599         }
1600         a = ctx->attr;
1601         BUG_ON(!a->non_resident);
1602         write_lock_irqsave(&ni->size_lock, flags);
1603         BUG_ON(end > ni->allocated_size);
1604         ni->initialized_size = end;
1605         a->data.non_resident.initialized_size = cpu_to_sle64(end);
1606         if (end > i_size_read(vi)) {
1607                 i_size_write(vi, end);
1608                 a->data.non_resident.data_size =
1609                                 a->data.non_resident.initialized_size;
1610         }
1611         write_unlock_irqrestore(&ni->size_lock, flags);
1612         /* Mark the mft record dirty, so it gets written back. */
1613         flush_dcache_mft_record_page(ctx->ntfs_ino);
1614         mark_mft_record_dirty(ctx->ntfs_ino);
1615         ntfs_attr_put_search_ctx(ctx);
1616         unmap_mft_record(base_ni);
1617         ntfs_debug("Done.");
1618         return 0;
1619 err_out:
1620         if (ctx)
1621                 ntfs_attr_put_search_ctx(ctx);
1622         if (m)
1623                 unmap_mft_record(base_ni);
1624         ntfs_error(vi->i_sb, "Failed to update initialized_size/i_size (error "
1625                         "code %i).", err);
1626         if (err != -ENOMEM) {
1627                 NVolSetErrors(ni->vol);
1628                 make_bad_inode(VFS_I(base_ni));
1629                 make_bad_inode(vi);
1630         }
1631         return err;
1632 }
1633
1634 /**
1635  * ntfs_commit_pages_after_write - commit the received data
1636  * @pages:      array of destination pages
1637  * @nr_pages:   number of pages in @pages
1638  * @pos:        byte position in file at which the write begins
1639  * @bytes:      number of bytes to be written
1640  *
1641  * This is called from ntfs_file_buffered_write() with i_mutex held on the inode
1642  * (@pages[0]->mapping->host).  There are @nr_pages pages in @pages which are
1643  * locked but not kmap()ped.  The source data has already been copied into the
1644  * @page.  ntfs_prepare_pages_for_non_resident_write() has been called before
1645  * the data was copied (for non-resident attributes only) and it returned
1646  * success.
1647  *
1648  * Need to set uptodate and mark dirty all buffers within the boundary of the
1649  * write.  If all buffers in a page are uptodate we set the page uptodate, too.
1650  *
1651  * Setting the buffers dirty ensures that they get written out later when
1652  * ntfs_writepage() is invoked by the VM.
1653  *
1654  * Finally, we need to update i_size and initialized_size as appropriate both
1655  * in the inode and the mft record.
1656  *
1657  * This is modelled after fs/buffer.c::generic_commit_write(), which marks
1658  * buffers uptodate and dirty, sets the page uptodate if all buffers in the
1659  * page are uptodate, and updates i_size if the end of io is beyond i_size.  In
1660  * that case, it also marks the inode dirty.
1661  *
1662  * If things have gone as outlined in
1663  * ntfs_prepare_pages_for_non_resident_write(), we do not need to do any page
1664  * content modifications here for non-resident attributes.  For resident
1665  * attributes we need to do the uptodate bringing here which we combine with
1666  * the copying into the mft record which means we save one atomic kmap.
1667  *
1668  * Return 0 on success or -errno on error.
1669  */
1670 static int ntfs_commit_pages_after_write(struct page **pages,
1671                 const unsigned nr_pages, s64 pos, size_t bytes)
1672 {
1673         s64 end, initialized_size;
1674         loff_t i_size;
1675         struct inode *vi;
1676         ntfs_inode *ni, *base_ni;
1677         struct page *page;
1678         ntfs_attr_search_ctx *ctx;
1679         MFT_RECORD *m;
1680         ATTR_RECORD *a;
1681         char *kattr, *kaddr;
1682         unsigned long flags;
1683         u32 attr_len;
1684         int err;
1685
1686         BUG_ON(!nr_pages);
1687         BUG_ON(!pages);
1688         page = pages[0];
1689         BUG_ON(!page);
1690         vi = page->mapping->host;
1691         ni = NTFS_I(vi);
1692         ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, start page "
1693                         "index 0x%lx, nr_pages 0x%x, pos 0x%llx, bytes 0x%zx.",
1694                         vi->i_ino, ni->type, page->index, nr_pages,
1695                         (long long)pos, bytes);
1696         if (NInoNonResident(ni))
1697                 return ntfs_commit_pages_after_non_resident_write(pages,
1698                                 nr_pages, pos, bytes);
1699         BUG_ON(nr_pages > 1);
1700         /*
1701          * Attribute is resident, implying it is not compressed, encrypted, or
1702          * sparse.
1703          */
1704         if (!NInoAttr(ni))
1705                 base_ni = ni;
1706         else
1707                 base_ni = ni->ext.base_ntfs_ino;
1708         BUG_ON(NInoNonResident(ni));
1709         /* Map, pin, and lock the mft record. */
1710         m = map_mft_record(base_ni);
1711         if (IS_ERR(m)) {
1712                 err = PTR_ERR(m);
1713                 m = NULL;
1714                 ctx = NULL;
1715                 goto err_out;
1716         }
1717         ctx = ntfs_attr_get_search_ctx(base_ni, m);
1718         if (unlikely(!ctx)) {
1719                 err = -ENOMEM;
1720                 goto err_out;
1721         }
1722         err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1723                         CASE_SENSITIVE, 0, NULL, 0, ctx);
1724         if (unlikely(err)) {
1725                 if (err == -ENOENT)
1726                         err = -EIO;
1727                 goto err_out;
1728         }
1729         a = ctx->attr;
1730         BUG_ON(a->non_resident);
1731         /* The total length of the attribute value. */
1732         attr_len = le32_to_cpu(a->data.resident.value_length);
1733         i_size = i_size_read(vi);
1734         BUG_ON(attr_len != i_size);
1735         BUG_ON(pos > attr_len);
1736         end = pos + bytes;
1737         BUG_ON(end > le32_to_cpu(a->length) -
1738                         le16_to_cpu(a->data.resident.value_offset));
1739         kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
1740         kaddr = kmap_atomic(page, KM_USER0);
1741         /* Copy the received data from the page to the mft record. */
1742         memcpy(kattr + pos, kaddr + pos, bytes);
1743         /* Update the attribute length if necessary. */
1744         if (end > attr_len) {
1745                 attr_len = end;
1746                 a->data.resident.value_length = cpu_to_le32(attr_len);
1747         }
1748         /*
1749          * If the page is not uptodate, bring the out of bounds area(s)
1750          * uptodate by copying data from the mft record to the page.
1751          */
1752         if (!PageUptodate(page)) {
1753                 if (pos > 0)
1754                         memcpy(kaddr, kattr, pos);
1755                 if (end < attr_len)
1756                         memcpy(kaddr + end, kattr + end, attr_len - end);
1757                 /* Zero the region outside the end of the attribute value. */
1758                 memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
1759                 flush_dcache_page(page);
1760                 SetPageUptodate(page);
1761         }
1762         kunmap_atomic(kaddr, KM_USER0);
1763         /* Update initialized_size/i_size if necessary. */
1764         read_lock_irqsave(&ni->size_lock, flags);
1765         initialized_size = ni->initialized_size;
1766         BUG_ON(end > ni->allocated_size);
1767         read_unlock_irqrestore(&ni->size_lock, flags);
1768         BUG_ON(initialized_size != i_size);
1769         if (end > initialized_size) {
1770                 unsigned long flags;
1771
1772                 write_lock_irqsave(&ni->size_lock, flags);
1773                 ni->initialized_size = end;
1774                 i_size_write(vi, end);
1775                 write_unlock_irqrestore(&ni->size_lock, flags);
1776         }
1777         /* Mark the mft record dirty, so it gets written back. */
1778         flush_dcache_mft_record_page(ctx->ntfs_ino);
1779         mark_mft_record_dirty(ctx->ntfs_ino);
1780         ntfs_attr_put_search_ctx(ctx);
1781         unmap_mft_record(base_ni);
1782         ntfs_debug("Done.");
1783         return 0;
1784 err_out:
1785         if (err == -ENOMEM) {
1786                 ntfs_warning(vi->i_sb, "Error allocating memory required to "
1787                                 "commit the write.");
1788                 if (PageUptodate(page)) {
1789                         ntfs_warning(vi->i_sb, "Page is uptodate, setting "
1790                                         "dirty so the write will be retried "
1791                                         "later on by the VM.");
1792                         /*
1793                          * Put the page on mapping->dirty_pages, but leave its
1794                          * buffers' dirty state as-is.
1795                          */
1796                         __set_page_dirty_nobuffers(page);
1797                         err = 0;
1798                 } else
1799                         ntfs_error(vi->i_sb, "Page is not uptodate.  Written "
1800                                         "data has been lost.");
1801         } else {
1802                 ntfs_error(vi->i_sb, "Resident attribute commit write failed "
1803                                 "with error %i.", err);
1804                 NVolSetErrors(ni->vol);
1805                 make_bad_inode(VFS_I(base_ni));
1806                 make_bad_inode(vi);
1807         }
1808         if (ctx)
1809                 ntfs_attr_put_search_ctx(ctx);
1810         if (m)
1811                 unmap_mft_record(base_ni);
1812         return err;
1813 }
1814
1815 /**
1816  * ntfs_file_buffered_write -
1817  *
1818  * Locking: The vfs is holding ->i_mutex on the inode.
1819  */
1820 static ssize_t ntfs_file_buffered_write(struct kiocb *iocb,
1821                 const struct iovec *iov, unsigned long nr_segs,
1822                 loff_t pos, loff_t *ppos, size_t count)
1823 {
1824         struct file *file = iocb->ki_filp;
1825         struct address_space *mapping = file->f_mapping;
1826         struct inode *vi = mapping->host;
1827         ntfs_inode *ni = NTFS_I(vi);
1828         ntfs_volume *vol = ni->vol;
1829         struct page *pages[NTFS_MAX_PAGES_PER_CLUSTER];
1830         struct page *cached_page = NULL;
1831         char __user *buf = NULL;
1832         s64 end, ll;
1833         VCN last_vcn;
1834         LCN lcn;
1835         unsigned long flags;
1836         size_t bytes, iov_ofs = 0;      /* Offset in the current iovec. */
1837         ssize_t status, written;
1838         unsigned nr_pages;
1839         int err;
1840         struct pagevec lru_pvec;
1841
1842         ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
1843                         "pos 0x%llx, count 0x%lx.",
1844                         vi->i_ino, (unsigned)le32_to_cpu(ni->type),
1845                         (unsigned long long)pos, (unsigned long)count);
1846         if (unlikely(!count))
1847                 return 0;
1848         BUG_ON(NInoMstProtected(ni));
1849         /*
1850          * If the attribute is not an index root and it is encrypted or
1851          * compressed, we cannot write to it yet.  Note we need to check for
1852          * AT_INDEX_ALLOCATION since this is the type of both directory and
1853          * index inodes.
1854          */
1855         if (ni->type != AT_INDEX_ALLOCATION) {
1856                 /* If file is encrypted, deny access, just like NT4. */
1857                 if (NInoEncrypted(ni)) {
1858                         /*
1859                          * Reminder for later: Encrypted files are _always_
1860                          * non-resident so that the content can always be
1861                          * encrypted.
1862                          */
1863                         ntfs_debug("Denying write access to encrypted file.");
1864                         return -EACCES;
1865                 }
1866                 if (NInoCompressed(ni)) {
1867                         /* Only unnamed $DATA attribute can be compressed. */
1868                         BUG_ON(ni->type != AT_DATA);
1869                         BUG_ON(ni->name_len);
1870                         /*
1871                          * Reminder for later: If resident, the data is not
1872                          * actually compressed.  Only on the switch to non-
1873                          * resident does compression kick in.  This is in
1874                          * contrast to encrypted files (see above).
1875                          */
1876                         ntfs_error(vi->i_sb, "Writing to compressed files is "
1877                                         "not implemented yet.  Sorry.");
1878                         return -EOPNOTSUPP;
1879                 }
1880         }
1881         /*
1882          * If a previous ntfs_truncate() failed, repeat it and abort if it
1883          * fails again.
1884          */
1885         if (unlikely(NInoTruncateFailed(ni))) {
1886                 down_write(&vi->i_alloc_sem);
1887                 err = ntfs_truncate(vi);
1888                 up_write(&vi->i_alloc_sem);
1889                 if (err || NInoTruncateFailed(ni)) {
1890                         if (!err)
1891                                 err = -EIO;
1892                         ntfs_error(vol->sb, "Cannot perform write to inode "
1893                                         "0x%lx, attribute type 0x%x, because "
1894                                         "ntfs_truncate() failed (error code "
1895                                         "%i).", vi->i_ino,
1896                                         (unsigned)le32_to_cpu(ni->type), err);
1897                         return err;
1898                 }
1899         }
1900         /* The first byte after the write. */
1901         end = pos + count;
1902         /*
1903          * If the write goes beyond the allocated size, extend the allocation
1904          * to cover the whole of the write, rounded up to the nearest cluster.
1905          */
1906         read_lock_irqsave(&ni->size_lock, flags);
1907         ll = ni->allocated_size;
1908         read_unlock_irqrestore(&ni->size_lock, flags);
1909         if (end > ll) {
1910                 /* Extend the allocation without changing the data size. */
1911                 ll = ntfs_attr_extend_allocation(ni, end, -1, pos);
1912                 if (likely(ll >= 0)) {
1913                         BUG_ON(pos >= ll);
1914                         /* If the extension was partial truncate the write. */
1915                         if (end > ll) {
1916                                 ntfs_debug("Truncating write to inode 0x%lx, "
1917                                                 "attribute type 0x%x, because "
1918                                                 "the allocation was only "
1919                                                 "partially extended.",
1920                                                 vi->i_ino, (unsigned)
1921                                                 le32_to_cpu(ni->type));
1922                                 end = ll;
1923                                 count = ll - pos;
1924                         }
1925                 } else {
1926                         err = ll;
1927                         read_lock_irqsave(&ni->size_lock, flags);
1928                         ll = ni->allocated_size;
1929                         read_unlock_irqrestore(&ni->size_lock, flags);
1930                         /* Perform a partial write if possible or fail. */
1931                         if (pos < ll) {
1932                                 ntfs_debug("Truncating write to inode 0x%lx, "
1933                                                 "attribute type 0x%x, because "
1934                                                 "extending the allocation "
1935                                                 "failed (error code %i).",
1936                                                 vi->i_ino, (unsigned)
1937                                                 le32_to_cpu(ni->type), err);
1938                                 end = ll;
1939                                 count = ll - pos;
1940                         } else {
1941                                 ntfs_error(vol->sb, "Cannot perform write to "
1942                                                 "inode 0x%lx, attribute type "
1943                                                 "0x%x, because extending the "
1944                                                 "allocation failed (error "
1945                                                 "code %i).", vi->i_ino,
1946                                                 (unsigned)
1947                                                 le32_to_cpu(ni->type), err);
1948                                 return err;
1949                         }
1950                 }
1951         }
1952         pagevec_init(&lru_pvec, 0);
1953         written = 0;
1954         /*
1955          * If the write starts beyond the initialized size, extend it up to the
1956          * beginning of the write and initialize all non-sparse space between
1957          * the old initialized size and the new one.  This automatically also
1958          * increments the vfs inode->i_size to keep it above or equal to the
1959          * initialized_size.
1960          */
1961         read_lock_irqsave(&ni->size_lock, flags);
1962         ll = ni->initialized_size;
1963         read_unlock_irqrestore(&ni->size_lock, flags);
1964         if (pos > ll) {
1965                 err = ntfs_attr_extend_initialized(ni, pos, &cached_page,
1966                                 &lru_pvec);
1967                 if (err < 0) {
1968                         ntfs_error(vol->sb, "Cannot perform write to inode "
1969                                         "0x%lx, attribute type 0x%x, because "
1970                                         "extending the initialized size "
1971                                         "failed (error code %i).", vi->i_ino,
1972                                         (unsigned)le32_to_cpu(ni->type), err);
1973                         status = err;
1974                         goto err_out;
1975                 }
1976         }
1977         /*
1978          * Determine the number of pages per cluster for non-resident
1979          * attributes.
1980          */
1981         nr_pages = 1;
1982         if (vol->cluster_size > PAGE_CACHE_SIZE && NInoNonResident(ni))
1983                 nr_pages = vol->cluster_size >> PAGE_CACHE_SHIFT;
1984         /* Finally, perform the actual write. */
1985         last_vcn = -1;
1986         if (likely(nr_segs == 1))
1987                 buf = iov->iov_base;
1988         do {
1989                 VCN vcn;
1990                 pgoff_t idx, start_idx;
1991                 unsigned ofs, do_pages, u;
1992                 size_t copied;
1993
1994                 start_idx = idx = pos >> PAGE_CACHE_SHIFT;
1995                 ofs = pos & ~PAGE_CACHE_MASK;
1996                 bytes = PAGE_CACHE_SIZE - ofs;
1997                 do_pages = 1;
1998                 if (nr_pages > 1) {
1999                         vcn = pos >> vol->cluster_size_bits;
2000                         if (vcn != last_vcn) {
2001                                 last_vcn = vcn;
2002                                 /*
2003                                  * Get the lcn of the vcn the write is in.  If
2004                                  * it is a hole, need to lock down all pages in
2005                                  * the cluster.
2006                                  */
2007                                 down_read(&ni->runlist.lock);
2008                                 lcn = ntfs_attr_vcn_to_lcn_nolock(ni, pos >>
2009                                                 vol->cluster_size_bits, FALSE);
2010                                 up_read(&ni->runlist.lock);
2011                                 if (unlikely(lcn < LCN_HOLE)) {
2012                                         status = -EIO;
2013                                         if (lcn == LCN_ENOMEM)
2014                                                 status = -ENOMEM;
2015                                         else
2016                                                 ntfs_error(vol->sb, "Cannot "
2017                                                         "perform write to "
2018                                                         "inode 0x%lx, "
2019                                                         "attribute type 0x%x, "
2020                                                         "because the attribute "
2021                                                         "is corrupt.",
2022                                                         vi->i_ino, (unsigned)
2023                                                         le32_to_cpu(ni->type));
2024                                         break;
2025                                 }
2026                                 if (lcn == LCN_HOLE) {
2027                                         start_idx = (pos & ~(s64)
2028                                                         vol->cluster_size_mask)
2029                                                         >> PAGE_CACHE_SHIFT;
2030                                         bytes = vol->cluster_size - (pos &
2031                                                         vol->cluster_size_mask);
2032                                         do_pages = nr_pages;
2033                                 }
2034                         }
2035                 }
2036                 if (bytes > count)
2037                         bytes = count;
2038                 /*
2039                  * Bring in the user page(s) that we will copy from _first_.
2040                  * Otherwise there is a nasty deadlock on copying from the same
2041                  * page(s) as we are writing to, without it/them being marked
2042                  * up-to-date.  Note, at present there is nothing to stop the
2043                  * pages being swapped out between us bringing them into memory
2044                  * and doing the actual copying.
2045                  */
2046                 if (likely(nr_segs == 1))
2047                         ntfs_fault_in_pages_readable(buf, bytes);
2048                 else
2049                         ntfs_fault_in_pages_readable_iovec(iov, iov_ofs, bytes);
2050                 /* Get and lock @do_pages starting at index @start_idx. */
2051                 status = __ntfs_grab_cache_pages(mapping, start_idx, do_pages,
2052                                 pages, &cached_page, &lru_pvec);
2053                 if (unlikely(status))
2054                         break;
2055                 /*
2056                  * For non-resident attributes, we need to fill any holes with
2057                  * actual clusters and ensure all bufferes are mapped.  We also
2058                  * need to bring uptodate any buffers that are only partially
2059                  * being written to.
2060                  */
2061                 if (NInoNonResident(ni)) {
2062                         status = ntfs_prepare_pages_for_non_resident_write(
2063                                         pages, do_pages, pos, bytes);
2064                         if (unlikely(status)) {
2065                                 loff_t i_size;
2066
2067                                 do {
2068                                         unlock_page(pages[--do_pages]);
2069                                         page_cache_release(pages[do_pages]);
2070                                 } while (do_pages);
2071                                 /*
2072                                  * The write preparation may have instantiated
2073                                  * allocated space outside i_size.  Trim this
2074                                  * off again.  We can ignore any errors in this
2075                                  * case as we will just be waisting a bit of
2076                                  * allocated space, which is not a disaster.
2077                                  */
2078                                 i_size = i_size_read(vi);
2079                                 if (pos + bytes > i_size)
2080                                         vmtruncate(vi, i_size);
2081                                 break;
2082                         }
2083                 }
2084                 u = (pos >> PAGE_CACHE_SHIFT) - pages[0]->index;
2085                 if (likely(nr_segs == 1)) {
2086                         copied = ntfs_copy_from_user(pages + u, do_pages - u,
2087                                         ofs, buf, bytes);
2088                         buf += copied;
2089                 } else
2090                         copied = ntfs_copy_from_user_iovec(pages + u,
2091                                         do_pages - u, ofs, &iov, &iov_ofs,
2092                                         bytes);
2093                 ntfs_flush_dcache_pages(pages + u, do_pages - u);
2094                 status = ntfs_commit_pages_after_write(pages, do_pages, pos,
2095                                 bytes);
2096                 if (likely(!status)) {
2097                         written += copied;
2098                         count -= copied;
2099                         pos += copied;
2100                         if (unlikely(copied != bytes))
2101                                 status = -EFAULT;
2102                 }
2103                 do {
2104                         unlock_page(pages[--do_pages]);
2105                         mark_page_accessed(pages[do_pages]);
2106                         page_cache_release(pages[do_pages]);
2107                 } while (do_pages);
2108                 if (unlikely(status))
2109                         break;
2110                 balance_dirty_pages_ratelimited(mapping);
2111                 cond_resched();
2112         } while (count);
2113 err_out:
2114         *ppos = pos;
2115         if (cached_page)
2116                 page_cache_release(cached_page);
2117         /* For now, when the user asks for O_SYNC, we actually give O_DSYNC. */
2118         if (likely(!status)) {
2119                 if (unlikely((file->f_flags & O_SYNC) || IS_SYNC(vi))) {
2120                         if (!mapping->a_ops->writepage || !is_sync_kiocb(iocb))
2121                                 status = generic_osync_inode(vi, mapping,
2122                                                 OSYNC_METADATA|OSYNC_DATA);
2123                 }
2124         }
2125         pagevec_lru_add(&lru_pvec);
2126         ntfs_debug("Done.  Returning %s (written 0x%lx, status %li).",
2127                         written ? "written" : "status", (unsigned long)written,
2128                         (long)status);
2129         return written ? written : status;
2130 }
2131
2132 /**
2133  * ntfs_file_aio_write_nolock -
2134  */
2135 static ssize_t ntfs_file_aio_write_nolock(struct kiocb *iocb,
2136                 const struct iovec *iov, unsigned long nr_segs, loff_t *ppos)
2137 {
2138         struct file *file = iocb->ki_filp;
2139         struct address_space *mapping = file->f_mapping;
2140         struct inode *inode = mapping->host;
2141         loff_t pos;
2142         unsigned long seg;
2143         size_t count;           /* after file limit checks */
2144         ssize_t written, err;
2145
2146         count = 0;
2147         for (seg = 0; seg < nr_segs; seg++) {
2148                 const struct iovec *iv = &iov[seg];
2149                 /*
2150                  * If any segment has a negative length, or the cumulative
2151                  * length ever wraps negative then return -EINVAL.
2152                  */
2153                 count += iv->iov_len;
2154                 if (unlikely((ssize_t)(count|iv->iov_len) < 0))
2155                         return -EINVAL;
2156                 if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
2157                         continue;
2158                 if (!seg)
2159                         return -EFAULT;
2160                 nr_segs = seg;
2161                 count -= iv->iov_len;   /* This segment is no good */
2162                 break;
2163         }
2164         pos = *ppos;
2165         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
2166         /* We can write back this queue in page reclaim. */
2167         current->backing_dev_info = mapping->backing_dev_info;
2168         written = 0;
2169         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
2170         if (err)
2171                 goto out;
2172         if (!count)
2173                 goto out;
2174         err = remove_suid(file->f_dentry);
2175         if (err)
2176                 goto out;
2177         file_update_time(file);
2178         written = ntfs_file_buffered_write(iocb, iov, nr_segs, pos, ppos,
2179                         count);
2180 out:
2181         current->backing_dev_info = NULL;
2182         return written ? written : err;
2183 }
2184
2185 /**
2186  * ntfs_file_aio_write -
2187  */
2188 static ssize_t ntfs_file_aio_write(struct kiocb *iocb, const char __user *buf,
2189                 size_t count, loff_t pos)
2190 {
2191         struct file *file = iocb->ki_filp;
2192         struct address_space *mapping = file->f_mapping;
2193         struct inode *inode = mapping->host;
2194         ssize_t ret;
2195         struct iovec local_iov = { .iov_base = (void __user *)buf,
2196                                    .iov_len = count };
2197
2198         BUG_ON(iocb->ki_pos != pos);
2199
2200         mutex_lock(&inode->i_mutex);
2201         ret = ntfs_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
2202         mutex_unlock(&inode->i_mutex);
2203         if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
2204                 int err = sync_page_range(inode, mapping, pos, ret);
2205                 if (err < 0)
2206                         ret = err;
2207         }
2208         return ret;
2209 }
2210
2211 /**
2212  * ntfs_file_writev -
2213  *
2214  * Basically the same as generic_file_writev() except that it ends up calling
2215  * ntfs_file_aio_write_nolock() instead of __generic_file_aio_write_nolock().
2216  */
2217 static ssize_t ntfs_file_writev(struct file *file, const struct iovec *iov,
2218                 unsigned long nr_segs, loff_t *ppos)
2219 {
2220         struct address_space *mapping = file->f_mapping;
2221         struct inode *inode = mapping->host;
2222         struct kiocb kiocb;
2223         ssize_t ret;
2224
2225         mutex_lock(&inode->i_mutex);
2226         init_sync_kiocb(&kiocb, file);
2227         ret = ntfs_file_aio_write_nolock(&kiocb, iov, nr_segs, ppos);
2228         if (ret == -EIOCBQUEUED)
2229                 ret = wait_on_sync_kiocb(&kiocb);
2230         mutex_unlock(&inode->i_mutex);
2231         if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
2232                 int err = sync_page_range(inode, mapping, *ppos - ret, ret);
2233                 if (err < 0)
2234                         ret = err;
2235         }
2236         return ret;
2237 }
2238
2239 /**
2240  * ntfs_file_write - simple wrapper for ntfs_file_writev()
2241  */
2242 static ssize_t ntfs_file_write(struct file *file, const char __user *buf,
2243                 size_t count, loff_t *ppos)
2244 {
2245         struct iovec local_iov = { .iov_base = (void __user *)buf,
2246                                    .iov_len = count };
2247
2248         return ntfs_file_writev(file, &local_iov, 1, ppos);
2249 }
2250
2251 /**
2252  * ntfs_file_fsync - sync a file to disk
2253  * @filp:       file to be synced
2254  * @dentry:     dentry describing the file to sync
2255  * @datasync:   if non-zero only flush user data and not metadata
2256  *
2257  * Data integrity sync of a file to disk.  Used for fsync, fdatasync, and msync
2258  * system calls.  This function is inspired by fs/buffer.c::file_fsync().
2259  *
2260  * If @datasync is false, write the mft record and all associated extent mft
2261  * records as well as the $DATA attribute and then sync the block device.
2262  *
2263  * If @datasync is true and the attribute is non-resident, we skip the writing
2264  * of the mft record and all associated extent mft records (this might still
2265  * happen due to the write_inode_now() call).
2266  *
2267  * Also, if @datasync is true, we do not wait on the inode to be written out
2268  * but we always wait on the page cache pages to be written out.
2269  *
2270  * Note: In the past @filp could be NULL so we ignore it as we don't need it
2271  * anyway.
2272  *
2273  * Locking: Caller must hold i_mutex on the inode.
2274  *
2275  * TODO: We should probably also write all attribute/index inodes associated
2276  * with this inode but since we have no simple way of getting to them we ignore
2277  * this problem for now.
2278  */
2279 static int ntfs_file_fsync(struct file *filp, struct dentry *dentry,
2280                 int datasync)
2281 {
2282         struct inode *vi = dentry->d_inode;
2283         int err, ret = 0;
2284
2285         ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
2286         BUG_ON(S_ISDIR(vi->i_mode));
2287         if (!datasync || !NInoNonResident(NTFS_I(vi)))
2288                 ret = ntfs_write_inode(vi, 1);
2289         write_inode_now(vi, !datasync);
2290         /*
2291          * NOTE: If we were to use mapping->private_list (see ext2 and
2292          * fs/buffer.c) for dirty blocks then we could optimize the below to be
2293          * sync_mapping_buffers(vi->i_mapping).
2294          */
2295         err = sync_blockdev(vi->i_sb->s_bdev);
2296         if (unlikely(err && !ret))
2297                 ret = err;
2298         if (likely(!ret))
2299                 ntfs_debug("Done.");
2300         else
2301                 ntfs_warning(vi->i_sb, "Failed to f%ssync inode 0x%lx.  Error "
2302                                 "%u.", datasync ? "data" : "", vi->i_ino, -ret);
2303         return ret;
2304 }
2305
2306 #endif /* NTFS_RW */
2307
2308 struct file_operations ntfs_file_ops = {
2309         .llseek         = generic_file_llseek,   /* Seek inside file. */
2310         .read           = generic_file_read,     /* Read from file. */
2311         .aio_read       = generic_file_aio_read, /* Async read from file. */
2312         .readv          = generic_file_readv,    /* Read from file. */
2313 #ifdef NTFS_RW
2314         .write          = ntfs_file_write,       /* Write to file. */
2315         .aio_write      = ntfs_file_aio_write,   /* Async write to file. */
2316         .writev         = ntfs_file_writev,      /* Write to file. */
2317         /*.release      = ,*/                    /* Last file is closed.  See
2318                                                     fs/ext2/file.c::
2319                                                     ext2_release_file() for
2320                                                     how to use this to discard
2321                                                     preallocated space for
2322                                                     write opened files. */
2323         .fsync          = ntfs_file_fsync,       /* Sync a file to disk. */
2324         /*.aio_fsync    = ,*/                    /* Sync all outstanding async
2325                                                     i/o operations on a
2326                                                     kiocb. */
2327 #endif /* NTFS_RW */
2328         /*.ioctl        = ,*/                    /* Perform function on the
2329                                                     mounted filesystem. */
2330         .mmap           = generic_file_mmap,     /* Mmap file. */
2331         .open           = ntfs_file_open,        /* Open file. */
2332         .sendfile       = generic_file_sendfile, /* Zero-copy data send with
2333                                                     the data source being on
2334                                                     the ntfs partition.  We do
2335                                                     not need to care about the
2336                                                     data destination. */
2337         /*.sendpage     = ,*/                    /* Zero-copy data send with
2338                                                     the data destination being
2339                                                     on the ntfs partition.  We
2340                                                     do not need to care about
2341                                                     the data source. */
2342 };
2343
2344 struct inode_operations ntfs_file_inode_ops = {
2345 #ifdef NTFS_RW
2346         .truncate       = ntfs_truncate_vfs,
2347         .setattr        = ntfs_setattr,
2348 #endif /* NTFS_RW */
2349 };
2350
2351 struct file_operations ntfs_empty_file_ops = {};
2352
2353 struct inode_operations ntfs_empty_inode_ops = {};