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