linux/fs/ntfs/mft.c
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   1/**
   2 * mft.c - NTFS kernel mft record operations. Part of the Linux-NTFS project.
   3 *
   4 * Copyright (c) 2001-2012 Anton Altaparmakov and Tuxera Inc.
   5 * Copyright (c) 2002 Richard Russon
   6 *
   7 * This program/include file is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License as published
   9 * by the Free Software Foundation; either version 2 of the License, or
  10 * (at your option) any later version.
  11 *
  12 * This program/include file is distributed in the hope that it will be
  13 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  14 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program (in the main directory of the Linux-NTFS
  19 * distribution in the file COPYING); if not, write to the Free Software
  20 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 */
  22
  23#include <linux/buffer_head.h>
  24#include <linux/slab.h>
  25#include <linux/swap.h>
  26
  27#include "attrib.h"
  28#include "aops.h"
  29#include "bitmap.h"
  30#include "debug.h"
  31#include "dir.h"
  32#include "lcnalloc.h"
  33#include "malloc.h"
  34#include "mft.h"
  35#include "ntfs.h"
  36
  37/**
  38 * map_mft_record_page - map the page in which a specific mft record resides
  39 * @ni:         ntfs inode whose mft record page to map
  40 *
  41 * This maps the page in which the mft record of the ntfs inode @ni is situated
  42 * and returns a pointer to the mft record within the mapped page.
  43 *
  44 * Return value needs to be checked with IS_ERR() and if that is true PTR_ERR()
  45 * contains the negative error code returned.
  46 */
  47static inline MFT_RECORD *map_mft_record_page(ntfs_inode *ni)
  48{
  49        loff_t i_size;
  50        ntfs_volume *vol = ni->vol;
  51        struct inode *mft_vi = vol->mft_ino;
  52        struct page *page;
  53        unsigned long index, end_index;
  54        unsigned ofs;
  55
  56        BUG_ON(ni->page);
  57        /*
  58         * The index into the page cache and the offset within the page cache
  59         * page of the wanted mft record. FIXME: We need to check for
  60         * overflowing the unsigned long, but I don't think we would ever get
  61         * here if the volume was that big...
  62         */
  63        index = (u64)ni->mft_no << vol->mft_record_size_bits >>
  64                        PAGE_CACHE_SHIFT;
  65        ofs = (ni->mft_no << vol->mft_record_size_bits) & ~PAGE_CACHE_MASK;
  66
  67        i_size = i_size_read(mft_vi);
  68        /* The maximum valid index into the page cache for $MFT's data. */
  69        end_index = i_size >> PAGE_CACHE_SHIFT;
  70
  71        /* If the wanted index is out of bounds the mft record doesn't exist. */
  72        if (unlikely(index >= end_index)) {
  73                if (index > end_index || (i_size & ~PAGE_CACHE_MASK) < ofs +
  74                                vol->mft_record_size) {
  75                        page = ERR_PTR(-ENOENT);
  76                        ntfs_error(vol->sb, "Attempt to read mft record 0x%lx, "
  77                                        "which is beyond the end of the mft.  "
  78                                        "This is probably a bug in the ntfs "
  79                                        "driver.", ni->mft_no);
  80                        goto err_out;
  81                }
  82        }
  83        /* Read, map, and pin the page. */
  84        page = ntfs_map_page(mft_vi->i_mapping, index);
  85        if (likely(!IS_ERR(page))) {
  86                /* Catch multi sector transfer fixup errors. */
  87                if (likely(ntfs_is_mft_recordp((le32*)(page_address(page) +
  88                                ofs)))) {
  89                        ni->page = page;
  90                        ni->page_ofs = ofs;
  91                        return page_address(page) + ofs;
  92                }
  93                ntfs_error(vol->sb, "Mft record 0x%lx is corrupt.  "
  94                                "Run chkdsk.", ni->mft_no);
  95                ntfs_unmap_page(page);
  96                page = ERR_PTR(-EIO);
  97                NVolSetErrors(vol);
  98        }
  99err_out:
 100        ni->page = NULL;
 101        ni->page_ofs = 0;
 102        return (void*)page;
 103}
 104
 105/**
 106 * map_mft_record - map, pin and lock an mft record
 107 * @ni:         ntfs inode whose MFT record to map
 108 *
 109 * First, take the mrec_lock mutex.  We might now be sleeping, while waiting
 110 * for the mutex if it was already locked by someone else.
 111 *
 112 * The page of the record is mapped using map_mft_record_page() before being
 113 * returned to the caller.
 114 *
 115 * This in turn uses ntfs_map_page() to get the page containing the wanted mft
 116 * record (it in turn calls read_cache_page() which reads it in from disk if
 117 * necessary, increments the use count on the page so that it cannot disappear
 118 * under us and returns a reference to the page cache page).
 119 *
 120 * If read_cache_page() invokes ntfs_readpage() to load the page from disk, it
 121 * sets PG_locked and clears PG_uptodate on the page. Once I/O has completed
 122 * and the post-read mst fixups on each mft record in the page have been
 123 * performed, the page gets PG_uptodate set and PG_locked cleared (this is done
 124 * in our asynchronous I/O completion handler end_buffer_read_mft_async()).
 125 * ntfs_map_page() waits for PG_locked to become clear and checks if
 126 * PG_uptodate is set and returns an error code if not. This provides
 127 * sufficient protection against races when reading/using the page.
 128 *
 129 * However there is the write mapping to think about. Doing the above described
 130 * checking here will be fine, because when initiating the write we will set
 131 * PG_locked and clear PG_uptodate making sure nobody is touching the page
 132 * contents. Doing the locking this way means that the commit to disk code in
 133 * the page cache code paths is automatically sufficiently locked with us as
 134 * we will not touch a page that has been locked or is not uptodate. The only
 135 * locking problem then is them locking the page while we are accessing it.
 136 *
 137 * So that code will end up having to own the mrec_lock of all mft
 138 * records/inodes present in the page before I/O can proceed. In that case we
 139 * wouldn't need to bother with PG_locked and PG_uptodate as nobody will be
 140 * accessing anything without owning the mrec_lock mutex.  But we do need to
 141 * use them because of the read_cache_page() invocation and the code becomes so
 142 * much simpler this way that it is well worth it.
 143 *
 144 * The mft record is now ours and we return a pointer to it. You need to check
 145 * the returned pointer with IS_ERR() and if that is true, PTR_ERR() will return
 146 * the error code.
 147 *
 148 * NOTE: Caller is responsible for setting the mft record dirty before calling
 149 * unmap_mft_record(). This is obviously only necessary if the caller really
 150 * modified the mft record...
 151 * Q: Do we want to recycle one of the VFS inode state bits instead?
 152 * A: No, the inode ones mean we want to change the mft record, not we want to
 153 * write it out.
 154 */
 155MFT_RECORD *map_mft_record(ntfs_inode *ni)
 156{
 157        MFT_RECORD *m;
 158
 159        ntfs_debug("Entering for mft_no 0x%lx.", ni->mft_no);
 160
 161        /* Make sure the ntfs inode doesn't go away. */
 162        atomic_inc(&ni->count);
 163
 164        /* Serialize access to this mft record. */
 165        mutex_lock(&ni->mrec_lock);
 166
 167        m = map_mft_record_page(ni);
 168        if (likely(!IS_ERR(m)))
 169                return m;
 170
 171        mutex_unlock(&ni->mrec_lock);
 172        atomic_dec(&ni->count);
 173        ntfs_error(ni->vol->sb, "Failed with error code %lu.", -PTR_ERR(m));
 174        return m;
 175}
 176
 177/**
 178 * unmap_mft_record_page - unmap the page in which a specific mft record resides
 179 * @ni:         ntfs inode whose mft record page to unmap
 180 *
 181 * This unmaps the page in which the mft record of the ntfs inode @ni is
 182 * situated and returns. This is a NOOP if highmem is not configured.
 183 *
 184 * The unmap happens via ntfs_unmap_page() which in turn decrements the use
 185 * count on the page thus releasing it from the pinned state.
 186 *
 187 * We do not actually unmap the page from memory of course, as that will be
 188 * done by the page cache code itself when memory pressure increases or
 189 * whatever.
 190 */
 191static inline void unmap_mft_record_page(ntfs_inode *ni)
 192{
 193        BUG_ON(!ni->page);
 194
 195        // TODO: If dirty, blah...
 196        ntfs_unmap_page(ni->page);
 197        ni->page = NULL;
 198        ni->page_ofs = 0;
 199        return;
 200}
 201
 202/**
 203 * unmap_mft_record - release a mapped mft record
 204 * @ni:         ntfs inode whose MFT record to unmap
 205 *
 206 * We release the page mapping and the mrec_lock mutex which unmaps the mft
 207 * record and releases it for others to get hold of. We also release the ntfs
 208 * inode by decrementing the ntfs inode reference count.
 209 *
 210 * NOTE: If caller has modified the mft record, it is imperative to set the mft
 211 * record dirty BEFORE calling unmap_mft_record().
 212 */
 213void unmap_mft_record(ntfs_inode *ni)
 214{
 215        struct page *page = ni->page;
 216
 217        BUG_ON(!page);
 218
 219        ntfs_debug("Entering for mft_no 0x%lx.", ni->mft_no);
 220
 221        unmap_mft_record_page(ni);
 222        mutex_unlock(&ni->mrec_lock);
 223        atomic_dec(&ni->count);
 224        /*
 225         * If pure ntfs_inode, i.e. no vfs inode attached, we leave it to
 226         * ntfs_clear_extent_inode() in the extent inode case, and to the
 227         * caller in the non-extent, yet pure ntfs inode case, to do the actual
 228         * tear down of all structures and freeing of all allocated memory.
 229         */
 230        return;
 231}
 232
 233/**
 234 * map_extent_mft_record - load an extent inode and attach it to its base
 235 * @base_ni:    base ntfs inode
 236 * @mref:       mft reference of the extent inode to load
 237 * @ntfs_ino:   on successful return, pointer to the ntfs_inode structure
 238 *
 239 * Load the extent mft record @mref and attach it to its base inode @base_ni.
 240 * Return the mapped extent mft record if IS_ERR(result) is false.  Otherwise
 241 * PTR_ERR(result) gives the negative error code.
 242 *
 243 * On successful return, @ntfs_ino contains a pointer to the ntfs_inode
 244 * structure of the mapped extent inode.
 245 */
 246MFT_RECORD *map_extent_mft_record(ntfs_inode *base_ni, MFT_REF mref,
 247                ntfs_inode **ntfs_ino)
 248{
 249        MFT_RECORD *m;
 250        ntfs_inode *ni = NULL;
 251        ntfs_inode **extent_nis = NULL;
 252        int i;
 253        unsigned long mft_no = MREF(mref);
 254        u16 seq_no = MSEQNO(mref);
 255        bool destroy_ni = false;
 256
 257        ntfs_debug("Mapping extent mft record 0x%lx (base mft record 0x%lx).",
 258                        mft_no, base_ni->mft_no);
 259        /* Make sure the base ntfs inode doesn't go away. */
 260        atomic_inc(&base_ni->count);
 261        /*
 262         * Check if this extent inode has already been added to the base inode,
 263         * in which case just return it. If not found, add it to the base
 264         * inode before returning it.
 265         */
 266        mutex_lock(&base_ni->extent_lock);
 267        if (base_ni->nr_extents > 0) {
 268                extent_nis = base_ni->ext.extent_ntfs_inos;
 269                for (i = 0; i < base_ni->nr_extents; i++) {
 270                        if (mft_no != extent_nis[i]->mft_no)
 271                                continue;
 272                        ni = extent_nis[i];
 273                        /* Make sure the ntfs inode doesn't go away. */
 274                        atomic_inc(&ni->count);
 275                        break;
 276                }
 277        }
 278        if (likely(ni != NULL)) {
 279                mutex_unlock(&base_ni->extent_lock);
 280                atomic_dec(&base_ni->count);
 281                /* We found the record; just have to map and return it. */
 282                m = map_mft_record(ni);
 283                /* map_mft_record() has incremented this on success. */
 284                atomic_dec(&ni->count);
 285                if (likely(!IS_ERR(m))) {
 286                        /* Verify the sequence number. */
 287                        if (likely(le16_to_cpu(m->sequence_number) == seq_no)) {
 288                                ntfs_debug("Done 1.");
 289                                *ntfs_ino = ni;
 290                                return m;
 291                        }
 292                        unmap_mft_record(ni);
 293                        ntfs_error(base_ni->vol->sb, "Found stale extent mft "
 294                                        "reference! Corrupt filesystem. "
 295                                        "Run chkdsk.");
 296                        return ERR_PTR(-EIO);
 297                }
 298map_err_out:
 299                ntfs_error(base_ni->vol->sb, "Failed to map extent "
 300                                "mft record, error code %ld.", -PTR_ERR(m));
 301                return m;
 302        }
 303        /* Record wasn't there. Get a new ntfs inode and initialize it. */
 304        ni = ntfs_new_extent_inode(base_ni->vol->sb, mft_no);
 305        if (unlikely(!ni)) {
 306                mutex_unlock(&base_ni->extent_lock);
 307                atomic_dec(&base_ni->count);
 308                return ERR_PTR(-ENOMEM);
 309        }
 310        ni->vol = base_ni->vol;
 311        ni->seq_no = seq_no;
 312        ni->nr_extents = -1;
 313        ni->ext.base_ntfs_ino = base_ni;
 314        /* Now map the record. */
 315        m = map_mft_record(ni);
 316        if (IS_ERR(m)) {
 317                mutex_unlock(&base_ni->extent_lock);
 318                atomic_dec(&base_ni->count);
 319                ntfs_clear_extent_inode(ni);
 320                goto map_err_out;
 321        }
 322        /* Verify the sequence number if it is present. */
 323        if (seq_no && (le16_to_cpu(m->sequence_number) != seq_no)) {
 324                ntfs_error(base_ni->vol->sb, "Found stale extent mft "
 325                                "reference! Corrupt filesystem. Run chkdsk.");
 326                destroy_ni = true;
 327                m = ERR_PTR(-EIO);
 328                goto unm_err_out;
 329        }
 330        /* Attach extent inode to base inode, reallocating memory if needed. */
 331        if (!(base_ni->nr_extents & 3)) {
 332                ntfs_inode **tmp;
 333                int new_size = (base_ni->nr_extents + 4) * sizeof(ntfs_inode *);
 334
 335                tmp = kmalloc(new_size, GFP_NOFS);
 336                if (unlikely(!tmp)) {
 337                        ntfs_error(base_ni->vol->sb, "Failed to allocate "
 338                                        "internal buffer.");
 339                        destroy_ni = true;
 340                        m = ERR_PTR(-ENOMEM);
 341                        goto unm_err_out;
 342                }
 343                if (base_ni->nr_extents) {
 344                        BUG_ON(!base_ni->ext.extent_ntfs_inos);
 345                        memcpy(tmp, base_ni->ext.extent_ntfs_inos, new_size -
 346                                        4 * sizeof(ntfs_inode *));
 347                        kfree(base_ni->ext.extent_ntfs_inos);
 348                }
 349                base_ni->ext.extent_ntfs_inos = tmp;
 350        }
 351        base_ni->ext.extent_ntfs_inos[base_ni->nr_extents++] = ni;
 352        mutex_unlock(&base_ni->extent_lock);
 353        atomic_dec(&base_ni->count);
 354        ntfs_debug("Done 2.");
 355        *ntfs_ino = ni;
 356        return m;
 357unm_err_out:
 358        unmap_mft_record(ni);
 359        mutex_unlock(&base_ni->extent_lock);
 360        atomic_dec(&base_ni->count);
 361        /*
 362         * If the extent inode was not attached to the base inode we need to
 363         * release it or we will leak memory.
 364         */
 365        if (destroy_ni)
 366                ntfs_clear_extent_inode(ni);
 367        return m;
 368}
 369
 370#ifdef NTFS_RW
 371
 372/**
 373 * __mark_mft_record_dirty - set the mft record and the page containing it dirty
 374 * @ni:         ntfs inode describing the mapped mft record
 375 *
 376 * Internal function.  Users should call mark_mft_record_dirty() instead.
 377 *
 378 * Set the mapped (extent) mft record of the (base or extent) ntfs inode @ni,
 379 * as well as the page containing the mft record, dirty.  Also, mark the base
 380 * vfs inode dirty.  This ensures that any changes to the mft record are
 381 * written out to disk.
 382 *
 383 * NOTE:  We only set I_DIRTY_SYNC and I_DIRTY_DATASYNC (and not I_DIRTY_PAGES)
 384 * on the base vfs inode, because even though file data may have been modified,
 385 * it is dirty in the inode meta data rather than the data page cache of the
 386 * inode, and thus there are no data pages that need writing out.  Therefore, a
 387 * full mark_inode_dirty() is overkill.  A mark_inode_dirty_sync(), on the
 388 * other hand, is not sufficient, because ->write_inode needs to be called even
 389 * in case of fdatasync. This needs to happen or the file data would not
 390 * necessarily hit the device synchronously, even though the vfs inode has the
 391 * O_SYNC flag set.  Also, I_DIRTY_DATASYNC simply "feels" better than just
 392 * I_DIRTY_SYNC, since the file data has not actually hit the block device yet,
 393 * which is not what I_DIRTY_SYNC on its own would suggest.
 394 */
 395void __mark_mft_record_dirty(ntfs_inode *ni)
 396{
 397        ntfs_inode *base_ni;
 398
 399        ntfs_debug("Entering for inode 0x%lx.", ni->mft_no);
 400        BUG_ON(NInoAttr(ni));
 401        mark_ntfs_record_dirty(ni->page, ni->page_ofs);
 402        /* Determine the base vfs inode and mark it dirty, too. */
 403        mutex_lock(&ni->extent_lock);
 404        if (likely(ni->nr_extents >= 0))
 405                base_ni = ni;
 406        else
 407                base_ni = ni->ext.base_ntfs_ino;
 408        mutex_unlock(&ni->extent_lock);
 409        __mark_inode_dirty(VFS_I(base_ni), I_DIRTY_SYNC | I_DIRTY_DATASYNC);
 410}
 411
 412static const char *ntfs_please_email = "Please email "
 413                "linux-ntfs-dev@lists.sourceforge.net and say that you saw "
 414                "this message.  Thank you.";
 415
 416/**
 417 * ntfs_sync_mft_mirror_umount - synchronise an mft record to the mft mirror
 418 * @vol:        ntfs volume on which the mft record to synchronize resides
 419 * @mft_no:     mft record number of mft record to synchronize
 420 * @m:          mapped, mst protected (extent) mft record to synchronize
 421 *
 422 * Write the mapped, mst protected (extent) mft record @m with mft record
 423 * number @mft_no to the mft mirror ($MFTMirr) of the ntfs volume @vol,
 424 * bypassing the page cache and the $MFTMirr inode itself.
 425 *
 426 * This function is only for use at umount time when the mft mirror inode has
 427 * already been disposed off.  We BUG() if we are called while the mft mirror
 428 * inode is still attached to the volume.
 429 *
 430 * On success return 0.  On error return -errno.
 431 *
 432 * NOTE:  This function is not implemented yet as I am not convinced it can
 433 * actually be triggered considering the sequence of commits we do in super.c::
 434 * ntfs_put_super().  But just in case we provide this place holder as the
 435 * alternative would be either to BUG() or to get a NULL pointer dereference
 436 * and Oops.
 437 */
 438static int ntfs_sync_mft_mirror_umount(ntfs_volume *vol,
 439                const unsigned long mft_no, MFT_RECORD *m)
 440{
 441        BUG_ON(vol->mftmirr_ino);
 442        ntfs_error(vol->sb, "Umount time mft mirror syncing is not "
 443                        "implemented yet.  %s", ntfs_please_email);
 444        return -EOPNOTSUPP;
 445}
 446
 447/**
 448 * ntfs_sync_mft_mirror - synchronize an mft record to the mft mirror
 449 * @vol:        ntfs volume on which the mft record to synchronize resides
 450 * @mft_no:     mft record number of mft record to synchronize
 451 * @m:          mapped, mst protected (extent) mft record to synchronize
 452 * @sync:       if true, wait for i/o completion
 453 *
 454 * Write the mapped, mst protected (extent) mft record @m with mft record
 455 * number @mft_no to the mft mirror ($MFTMirr) of the ntfs volume @vol.
 456 *
 457 * On success return 0.  On error return -errno and set the volume errors flag
 458 * in the ntfs volume @vol.
 459 *
 460 * NOTE:  We always perform synchronous i/o and ignore the @sync parameter.
 461 *
 462 * TODO:  If @sync is false, want to do truly asynchronous i/o, i.e. just
 463 * schedule i/o via ->writepage or do it via kntfsd or whatever.
 464 */
 465int ntfs_sync_mft_mirror(ntfs_volume *vol, const unsigned long mft_no,
 466                MFT_RECORD *m, int sync)
 467{
 468        struct page *page;
 469        unsigned int blocksize = vol->sb->s_blocksize;
 470        int max_bhs = vol->mft_record_size / blocksize;
 471        struct buffer_head *bhs[max_bhs];
 472        struct buffer_head *bh, *head;
 473        u8 *kmirr;
 474        runlist_element *rl;
 475        unsigned int block_start, block_end, m_start, m_end, page_ofs;
 476        int i_bhs, nr_bhs, err = 0;
 477        unsigned char blocksize_bits = vol->sb->s_blocksize_bits;
 478
 479        ntfs_debug("Entering for inode 0x%lx.", mft_no);
 480        BUG_ON(!max_bhs);
 481        if (unlikely(!vol->mftmirr_ino)) {
 482                /* This could happen during umount... */
 483                err = ntfs_sync_mft_mirror_umount(vol, mft_no, m);
 484                if (likely(!err))
 485                        return err;
 486                goto err_out;
 487        }
 488        /* Get the page containing the mirror copy of the mft record @m. */
 489        page = ntfs_map_page(vol->mftmirr_ino->i_mapping, mft_no >>
 490                        (PAGE_CACHE_SHIFT - vol->mft_record_size_bits));
 491        if (IS_ERR(page)) {
 492                ntfs_error(vol->sb, "Failed to map mft mirror page.");
 493                err = PTR_ERR(page);
 494                goto err_out;
 495        }
 496        lock_page(page);
 497        BUG_ON(!PageUptodate(page));
 498        ClearPageUptodate(page);
 499        /* Offset of the mft mirror record inside the page. */
 500        page_ofs = (mft_no << vol->mft_record_size_bits) & ~PAGE_CACHE_MASK;
 501        /* The address in the page of the mirror copy of the mft record @m. */
 502        kmirr = page_address(page) + page_ofs;
 503        /* Copy the mst protected mft record to the mirror. */
 504        memcpy(kmirr, m, vol->mft_record_size);
 505        /* Create uptodate buffers if not present. */
 506        if (unlikely(!page_has_buffers(page))) {
 507                struct buffer_head *tail;
 508
 509                bh = head = alloc_page_buffers(page, blocksize, 1);
 510                do {
 511                        set_buffer_uptodate(bh);
 512                        tail = bh;
 513                        bh = bh->b_this_page;
 514                } while (bh);
 515                tail->b_this_page = head;
 516                attach_page_buffers(page, head);
 517        }
 518        bh = head = page_buffers(page);
 519        BUG_ON(!bh);
 520        rl = NULL;
 521        nr_bhs = 0;
 522        block_start = 0;
 523        m_start = kmirr - (u8*)page_address(page);
 524        m_end = m_start + vol->mft_record_size;
 525        do {
 526                block_end = block_start + blocksize;
 527                /* If the buffer is outside the mft record, skip it. */
 528                if (block_end <= m_start)
 529                        continue;
 530                if (unlikely(block_start >= m_end))
 531                        break;
 532                /* Need to map the buffer if it is not mapped already. */
 533                if (unlikely(!buffer_mapped(bh))) {
 534                        VCN vcn;
 535                        LCN lcn;
 536                        unsigned int vcn_ofs;
 537
 538                        bh->b_bdev = vol->sb->s_bdev;
 539                        /* Obtain the vcn and offset of the current block. */
 540                        vcn = ((VCN)mft_no << vol->mft_record_size_bits) +
 541                                        (block_start - m_start);
 542                        vcn_ofs = vcn & vol->cluster_size_mask;
 543                        vcn >>= vol->cluster_size_bits;
 544                        if (!rl) {
 545                                down_read(&NTFS_I(vol->mftmirr_ino)->
 546                                                runlist.lock);
 547                                rl = NTFS_I(vol->mftmirr_ino)->runlist.rl;
 548                                /*
 549                                 * $MFTMirr always has the whole of its runlist
 550                                 * in memory.
 551                                 */
 552                                BUG_ON(!rl);
 553                        }
 554                        /* Seek to element containing target vcn. */
 555                        while (rl->length && rl[1].vcn <= vcn)
 556                                rl++;
 557                        lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
 558                        /* For $MFTMirr, only lcn >= 0 is a successful remap. */
 559                        if (likely(lcn >= 0)) {
 560                                /* Setup buffer head to correct block. */
 561                                bh->b_blocknr = ((lcn <<
 562                                                vol->cluster_size_bits) +
 563                                                vcn_ofs) >> blocksize_bits;
 564                                set_buffer_mapped(bh);
 565                        } else {
 566                                bh->b_blocknr = -1;
 567                                ntfs_error(vol->sb, "Cannot write mft mirror "
 568                                                "record 0x%lx because its "
 569                                                "location on disk could not "
 570                                                "be determined (error code "
 571                                                "%lli).", mft_no,
 572                                                (long long)lcn);
 573                                err = -EIO;
 574                        }
 575                }
 576                BUG_ON(!buffer_uptodate(bh));
 577                BUG_ON(!nr_bhs && (m_start != block_start));
 578                BUG_ON(nr_bhs >= max_bhs);
 579                bhs[nr_bhs++] = bh;
 580                BUG_ON((nr_bhs >= max_bhs) && (m_end != block_end));
 581        } while (block_start = block_end, (bh = bh->b_this_page) != head);
 582        if (unlikely(rl))
 583                up_read(&NTFS_I(vol->mftmirr_ino)->runlist.lock);
 584        if (likely(!err)) {
 585                /* Lock buffers and start synchronous write i/o on them. */
 586                for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
 587                        struct buffer_head *tbh = bhs[i_bhs];
 588
 589                        if (!trylock_buffer(tbh))
 590                                BUG();
 591                        BUG_ON(!buffer_uptodate(tbh));
 592                        clear_buffer_dirty(tbh);
 593                        get_bh(tbh);
 594                        tbh->b_end_io = end_buffer_write_sync;
 595                        submit_bh(WRITE, tbh);
 596                }
 597                /* Wait on i/o completion of buffers. */
 598                for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
 599                        struct buffer_head *tbh = bhs[i_bhs];
 600
 601                        wait_on_buffer(tbh);
 602                        if (unlikely(!buffer_uptodate(tbh))) {
 603                                err = -EIO;
 604                                /*
 605                                 * Set the buffer uptodate so the page and
 606                                 * buffer states do not become out of sync.
 607                                 */
 608                                set_buffer_uptodate(tbh);
 609                        }
 610                }
 611        } else /* if (unlikely(err)) */ {
 612                /* Clean the buffers. */
 613                for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++)
 614                        clear_buffer_dirty(bhs[i_bhs]);
 615        }
 616        /* Current state: all buffers are clean, unlocked, and uptodate. */
 617        /* Remove the mst protection fixups again. */
 618        post_write_mst_fixup((NTFS_RECORD*)kmirr);
 619        flush_dcache_page(page);
 620        SetPageUptodate(page);
 621        unlock_page(page);
 622        ntfs_unmap_page(page);
 623        if (likely(!err)) {
 624                ntfs_debug("Done.");
 625        } else {
 626                ntfs_error(vol->sb, "I/O error while writing mft mirror "
 627                                "record 0x%lx!", mft_no);
 628err_out:
 629                ntfs_error(vol->sb, "Failed to synchronize $MFTMirr (error "
 630                                "code %i).  Volume will be left marked dirty "
 631                                "on umount.  Run ntfsfix on the partition "
 632                                "after umounting to correct this.", -err);
 633                NVolSetErrors(vol);
 634        }
 635        return err;
 636}
 637
 638/**
 639 * write_mft_record_nolock - write out a mapped (extent) mft record
 640 * @ni:         ntfs inode describing the mapped (extent) mft record
 641 * @m:          mapped (extent) mft record to write
 642 * @sync:       if true, wait for i/o completion
 643 *
 644 * Write the mapped (extent) mft record @m described by the (regular or extent)
 645 * ntfs inode @ni to backing store.  If the mft record @m has a counterpart in
 646 * the mft mirror, that is also updated.
 647 *
 648 * We only write the mft record if the ntfs inode @ni is dirty and the first
 649 * buffer belonging to its mft record is dirty, too.  We ignore the dirty state
 650 * of subsequent buffers because we could have raced with
 651 * fs/ntfs/aops.c::mark_ntfs_record_dirty().
 652 *
 653 * On success, clean the mft record and return 0.  On error, leave the mft
 654 * record dirty and return -errno.
 655 *
 656 * NOTE:  We always perform synchronous i/o and ignore the @sync parameter.
 657 * However, if the mft record has a counterpart in the mft mirror and @sync is
 658 * true, we write the mft record, wait for i/o completion, and only then write
 659 * the mft mirror copy.  This ensures that if the system crashes either the mft
 660 * or the mft mirror will contain a self-consistent mft record @m.  If @sync is
 661 * false on the other hand, we start i/o on both and then wait for completion
 662 * on them.  This provides a speedup but no longer guarantees that you will end
 663 * up with a self-consistent mft record in the case of a crash but if you asked
 664 * for asynchronous writing you probably do not care about that anyway.
 665 *
 666 * TODO:  If @sync is false, want to do truly asynchronous i/o, i.e. just
 667 * schedule i/o via ->writepage or do it via kntfsd or whatever.
 668 */
 669int write_mft_record_nolock(ntfs_inode *ni, MFT_RECORD *m, int sync)
 670{
 671        ntfs_volume *vol = ni->vol;
 672        struct page *page = ni->page;
 673        unsigned int blocksize = vol->sb->s_blocksize;
 674        unsigned char blocksize_bits = vol->sb->s_blocksize_bits;
 675        int max_bhs = vol->mft_record_size / blocksize;
 676        struct buffer_head *bhs[max_bhs];
 677        struct buffer_head *bh, *head;
 678        runlist_element *rl;
 679        unsigned int block_start, block_end, m_start, m_end;
 680        int i_bhs, nr_bhs, err = 0;
 681
 682        ntfs_debug("Entering for inode 0x%lx.", ni->mft_no);
 683        BUG_ON(NInoAttr(ni));
 684        BUG_ON(!max_bhs);
 685        BUG_ON(!PageLocked(page));
 686        /*
 687         * If the ntfs_inode is clean no need to do anything.  If it is dirty,
 688         * mark it as clean now so that it can be redirtied later on if needed.
 689         * There is no danger of races since the caller is holding the locks
 690         * for the mft record @m and the page it is in.
 691         */
 692        if (!NInoTestClearDirty(ni))
 693                goto done;
 694        bh = head = page_buffers(page);
 695        BUG_ON(!bh);
 696        rl = NULL;
 697        nr_bhs = 0;
 698        block_start = 0;
 699        m_start = ni->page_ofs;
 700        m_end = m_start + vol->mft_record_size;
 701        do {
 702                block_end = block_start + blocksize;
 703                /* If the buffer is outside the mft record, skip it. */
 704                if (block_end <= m_start)
 705                        continue;
 706                if (unlikely(block_start >= m_end))
 707                        break;
 708                /*
 709                 * If this block is not the first one in the record, we ignore
 710                 * the buffer's dirty state because we could have raced with a
 711                 * parallel mark_ntfs_record_dirty().
 712                 */
 713                if (block_start == m_start) {
 714                        /* This block is the first one in the record. */
 715                        if (!buffer_dirty(bh)) {
 716                                BUG_ON(nr_bhs);
 717                                /* Clean records are not written out. */
 718                                break;
 719                        }
 720                }
 721                /* Need to map the buffer if it is not mapped already. */
 722                if (unlikely(!buffer_mapped(bh))) {
 723                        VCN vcn;
 724                        LCN lcn;
 725                        unsigned int vcn_ofs;
 726
 727                        bh->b_bdev = vol->sb->s_bdev;
 728                        /* Obtain the vcn and offset of the current block. */
 729                        vcn = ((VCN)ni->mft_no << vol->mft_record_size_bits) +
 730                                        (block_start - m_start);
 731                        vcn_ofs = vcn & vol->cluster_size_mask;
 732                        vcn >>= vol->cluster_size_bits;
 733                        if (!rl) {
 734                                down_read(&NTFS_I(vol->mft_ino)->runlist.lock);
 735                                rl = NTFS_I(vol->mft_ino)->runlist.rl;
 736                                BUG_ON(!rl);
 737                        }
 738                        /* Seek to element containing target vcn. */
 739                        while (rl->length && rl[1].vcn <= vcn)
 740                                rl++;
 741                        lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
 742                        /* For $MFT, only lcn >= 0 is a successful remap. */
 743                        if (likely(lcn >= 0)) {
 744                                /* Setup buffer head to correct block. */
 745                                bh->b_blocknr = ((lcn <<
 746                                                vol->cluster_size_bits) +
 747                                                vcn_ofs) >> blocksize_bits;
 748                                set_buffer_mapped(bh);
 749                        } else {
 750                                bh->b_blocknr = -1;
 751                                ntfs_error(vol->sb, "Cannot write mft record "
 752                                                "0x%lx because its location "
 753                                                "on disk could not be "
 754                                                "determined (error code %lli).",
 755                                                ni->mft_no, (long long)lcn);
 756                                err = -EIO;
 757                        }
 758                }
 759                BUG_ON(!buffer_uptodate(bh));
 760                BUG_ON(!nr_bhs && (m_start != block_start));
 761                BUG_ON(nr_bhs >= max_bhs);
 762                bhs[nr_bhs++] = bh;
 763                BUG_ON((nr_bhs >= max_bhs) && (m_end != block_end));
 764        } while (block_start = block_end, (bh = bh->b_this_page) != head);
 765        if (unlikely(rl))
 766                up_read(&NTFS_I(vol->mft_ino)->runlist.lock);
 767        if (!nr_bhs)
 768                goto done;
 769        if (unlikely(err))
 770                goto cleanup_out;
 771        /* Apply the mst protection fixups. */
 772        err = pre_write_mst_fixup((NTFS_RECORD*)m, vol->mft_record_size);
 773        if (err) {
 774                ntfs_error(vol->sb, "Failed to apply mst fixups!");
 775                goto cleanup_out;
 776        }
 777        flush_dcache_mft_record_page(ni);
 778        /* Lock buffers and start synchronous write i/o on them. */
 779        for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
 780                struct buffer_head *tbh = bhs[i_bhs];
 781
 782                if (!trylock_buffer(tbh))
 783                        BUG();
 784                BUG_ON(!buffer_uptodate(tbh));
 785                clear_buffer_dirty(tbh);
 786                get_bh(tbh);
 787                tbh->b_end_io = end_buffer_write_sync;
 788                submit_bh(WRITE, tbh);
 789        }
 790        /* Synchronize the mft mirror now if not @sync. */
 791        if (!sync && ni->mft_no < vol->mftmirr_size)
 792                ntfs_sync_mft_mirror(vol, ni->mft_no, m, sync);
 793        /* Wait on i/o completion of buffers. */
 794        for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
 795                struct buffer_head *tbh = bhs[i_bhs];
 796
 797                wait_on_buffer(tbh);
 798                if (unlikely(!buffer_uptodate(tbh))) {
 799                        err = -EIO;
 800                        /*
 801                         * Set the buffer uptodate so the page and buffer
 802                         * states do not become out of sync.
 803                         */
 804                        if (PageUptodate(page))
 805                                set_buffer_uptodate(tbh);
 806                }
 807        }
 808        /* If @sync, now synchronize the mft mirror. */
 809        if (sync && ni->mft_no < vol->mftmirr_size)
 810                ntfs_sync_mft_mirror(vol, ni->mft_no, m, sync);
 811        /* Remove the mst protection fixups again. */
 812        post_write_mst_fixup((NTFS_RECORD*)m);
 813        flush_dcache_mft_record_page(ni);
 814        if (unlikely(err)) {
 815                /* I/O error during writing.  This is really bad! */
 816                ntfs_error(vol->sb, "I/O error while writing mft record "
 817                                "0x%lx!  Marking base inode as bad.  You "
 818                                "should unmount the volume and run chkdsk.",
 819                                ni->mft_no);
 820                goto err_out;
 821        }
 822done:
 823        ntfs_debug("Done.");
 824        return 0;
 825cleanup_out:
 826        /* Clean the buffers. */
 827        for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++)
 828                clear_buffer_dirty(bhs[i_bhs]);
 829err_out:
 830        /*
 831         * Current state: all buffers are clean, unlocked, and uptodate.
 832         * The caller should mark the base inode as bad so that no more i/o
 833         * happens.  ->clear_inode() will still be invoked so all extent inodes
 834         * and other allocated memory will be freed.
 835         */
 836        if (err == -ENOMEM) {
 837                ntfs_error(vol->sb, "Not enough memory to write mft record.  "
 838                                "Redirtying so the write is retried later.");
 839                mark_mft_record_dirty(ni);
 840                err = 0;
 841        } else
 842                NVolSetErrors(vol);
 843        return err;
 844}
 845
 846/**
 847 * ntfs_may_write_mft_record - check if an mft record may be written out
 848 * @vol:        [IN]  ntfs volume on which the mft record to check resides
 849 * @mft_no:     [IN]  mft record number of the mft record to check
 850 * @m:          [IN]  mapped mft record to check
 851 * @locked_ni:  [OUT] caller has to unlock this ntfs inode if one is returned
 852 *
 853 * Check if the mapped (base or extent) mft record @m with mft record number
 854 * @mft_no belonging to the ntfs volume @vol may be written out.  If necessary
 855 * and possible the ntfs inode of the mft record is locked and the base vfs
 856 * inode is pinned.  The locked ntfs inode is then returned in @locked_ni.  The
 857 * caller is responsible for unlocking the ntfs inode and unpinning the base
 858 * vfs inode.
 859 *
 860 * Return 'true' if the mft record may be written out and 'false' if not.
 861 *
 862 * The caller has locked the page and cleared the uptodate flag on it which
 863 * means that we can safely write out any dirty mft records that do not have
 864 * their inodes in icache as determined by ilookup5() as anyone
 865 * opening/creating such an inode would block when attempting to map the mft
 866 * record in read_cache_page() until we are finished with the write out.
 867 *
 868 * Here is a description of the tests we perform:
 869 *
 870 * If the inode is found in icache we know the mft record must be a base mft
 871 * record.  If it is dirty, we do not write it and return 'false' as the vfs
 872 * inode write paths will result in the access times being updated which would
 873 * cause the base mft record to be redirtied and written out again.  (We know
 874 * the access time update will modify the base mft record because Windows
 875 * chkdsk complains if the standard information attribute is not in the base
 876 * mft record.)
 877 *
 878 * If the inode is in icache and not dirty, we attempt to lock the mft record
 879 * and if we find the lock was already taken, it is not safe to write the mft
 880 * record and we return 'false'.
 881 *
 882 * If we manage to obtain the lock we have exclusive access to the mft record,
 883 * which also allows us safe writeout of the mft record.  We then set
 884 * @locked_ni to the locked ntfs inode and return 'true'.
 885 *
 886 * Note we cannot just lock the mft record and sleep while waiting for the lock
 887 * because this would deadlock due to lock reversal (normally the mft record is
 888 * locked before the page is locked but we already have the page locked here
 889 * when we try to lock the mft record).
 890 *
 891 * If the inode is not in icache we need to perform further checks.
 892 *
 893 * If the mft record is not a FILE record or it is a base mft record, we can
 894 * safely write it and return 'true'.
 895 *
 896 * We now know the mft record is an extent mft record.  We check if the inode
 897 * corresponding to its base mft record is in icache and obtain a reference to
 898 * it if it is.  If it is not, we can safely write it and return 'true'.
 899 *
 900 * We now have the base inode for the extent mft record.  We check if it has an
 901 * ntfs inode for the extent mft record attached and if not it is safe to write
 902 * the extent mft record and we return 'true'.
 903 *
 904 * The ntfs inode for the extent mft record is attached to the base inode so we
 905 * attempt to lock the extent mft record and if we find the lock was already
 906 * taken, it is not safe to write the extent mft record and we return 'false'.
 907 *
 908 * If we manage to obtain the lock we have exclusive access to the extent mft
 909 * record, which also allows us safe writeout of the extent mft record.  We
 910 * set the ntfs inode of the extent mft record clean and then set @locked_ni to
 911 * the now locked ntfs inode and return 'true'.
 912 *
 913 * Note, the reason for actually writing dirty mft records here and not just
 914 * relying on the vfs inode dirty code paths is that we can have mft records
 915 * modified without them ever having actual inodes in memory.  Also we can have
 916 * dirty mft records with clean ntfs inodes in memory.  None of the described
 917 * cases would result in the dirty mft records being written out if we only
 918 * relied on the vfs inode dirty code paths.  And these cases can really occur
 919 * during allocation of new mft records and in particular when the
 920 * initialized_size of the $MFT/$DATA attribute is extended and the new space
 921 * is initialized using ntfs_mft_record_format().  The clean inode can then
 922 * appear if the mft record is reused for a new inode before it got written
 923 * out.
 924 */
 925bool ntfs_may_write_mft_record(ntfs_volume *vol, const unsigned long mft_no,
 926                const MFT_RECORD *m, ntfs_inode **locked_ni)
 927{
 928        struct super_block *sb = vol->sb;
 929        struct inode *mft_vi = vol->mft_ino;
 930        struct inode *vi;
 931        ntfs_inode *ni, *eni, **extent_nis;
 932        int i;
 933        ntfs_attr na;
 934
 935        ntfs_debug("Entering for inode 0x%lx.", mft_no);
 936        /*
 937         * Normally we do not return a locked inode so set @locked_ni to NULL.
 938         */
 939        BUG_ON(!locked_ni);
 940        *locked_ni = NULL;
 941        /*
 942         * Check if the inode corresponding to this mft record is in the VFS
 943         * inode cache and obtain a reference to it if it is.
 944         */
 945        ntfs_debug("Looking for inode 0x%lx in icache.", mft_no);
 946        na.mft_no = mft_no;
 947        na.name = NULL;
 948        na.name_len = 0;
 949        na.type = AT_UNUSED;
 950        /*
 951         * Optimize inode 0, i.e. $MFT itself, since we have it in memory and
 952         * we get here for it rather often.
 953         */
 954        if (!mft_no) {
 955                /* Balance the below iput(). */
 956                vi = igrab(mft_vi);
 957                BUG_ON(vi != mft_vi);
 958        } else {
 959                /*
 960                 * Have to use ilookup5_nowait() since ilookup5() waits for the
 961                 * inode lock which causes ntfs to deadlock when a concurrent
 962                 * inode write via the inode dirty code paths and the page
 963                 * dirty code path of the inode dirty code path when writing
 964                 * $MFT occurs.
 965                 */
 966                vi = ilookup5_nowait(sb, mft_no, (test_t)ntfs_test_inode, &na);
 967        }
 968        if (vi) {
 969                ntfs_debug("Base inode 0x%lx is in icache.", mft_no);
 970                /* The inode is in icache. */
 971                ni = NTFS_I(vi);
 972                /* Take a reference to the ntfs inode. */
 973                atomic_inc(&ni->count);
 974                /* If the inode is dirty, do not write this record. */
 975                if (NInoDirty(ni)) {
 976                        ntfs_debug("Inode 0x%lx is dirty, do not write it.",
 977                                        mft_no);
 978                        atomic_dec(&ni->count);
 979                        iput(vi);
 980                        return false;
 981                }
 982                ntfs_debug("Inode 0x%lx is not dirty.", mft_no);
 983                /* The inode is not dirty, try to take the mft record lock. */
 984                if (unlikely(!mutex_trylock(&ni->mrec_lock))) {
 985                        ntfs_debug("Mft record 0x%lx is already locked, do "
 986                                        "not write it.", mft_no);
 987                        atomic_dec(&ni->count);
 988                        iput(vi);
 989                        return false;
 990                }
 991                ntfs_debug("Managed to lock mft record 0x%lx, write it.",
 992                                mft_no);
 993                /*
 994                 * The write has to occur while we hold the mft record lock so
 995                 * return the locked ntfs inode.
 996                 */
 997                *locked_ni = ni;
 998                return true;
 999        }
1000        ntfs_debug("Inode 0x%lx is not in icache.", mft_no);
1001        /* The inode is not in icache. */
1002        /* Write the record if it is not a mft record (type "FILE"). */
1003        if (!ntfs_is_mft_record(m->magic)) {
1004                ntfs_debug("Mft record 0x%lx is not a FILE record, write it.",
1005                                mft_no);
1006                return true;
1007        }
1008        /* Write the mft record if it is a base inode. */
1009        if (!m->base_mft_record) {
1010                ntfs_debug("Mft record 0x%lx is a base record, write it.",
1011                                mft_no);
1012                return true;
1013        }
1014        /*
1015         * This is an extent mft record.  Check if the inode corresponding to
1016         * its base mft record is in icache and obtain a reference to it if it
1017         * is.
1018         */
1019        na.mft_no = MREF_LE(m->base_mft_record);
1020        ntfs_debug("Mft record 0x%lx is an extent record.  Looking for base "
1021                        "inode 0x%lx in icache.", mft_no, na.mft_no);
1022        if (!na.mft_no) {
1023                /* Balance the below iput(). */
1024                vi = igrab(mft_vi);
1025                BUG_ON(vi != mft_vi);
1026        } else
1027                vi = ilookup5_nowait(sb, na.mft_no, (test_t)ntfs_test_inode,
1028                                &na);
1029        if (!vi) {
1030                /*
1031                 * The base inode is not in icache, write this extent mft
1032                 * record.
1033                 */
1034                ntfs_debug("Base inode 0x%lx is not in icache, write the "
1035                                "extent record.", na.mft_no);
1036                return true;
1037        }
1038        ntfs_debug("Base inode 0x%lx is in icache.", na.mft_no);
1039        /*
1040         * The base inode is in icache.  Check if it has the extent inode
1041         * corresponding to this extent mft record attached.
1042         */
1043        ni = NTFS_I(vi);
1044        mutex_lock(&ni->extent_lock);
1045        if (ni->nr_extents <= 0) {
1046                /*
1047                 * The base inode has no attached extent inodes, write this
1048                 * extent mft record.
1049                 */
1050                mutex_unlock(&ni->extent_lock);
1051                iput(vi);
1052                ntfs_debug("Base inode 0x%lx has no attached extent inodes, "
1053                                "write the extent record.", na.mft_no);
1054                return true;
1055        }
1056        /* Iterate over the attached extent inodes. */
1057        extent_nis = ni->ext.extent_ntfs_inos;
1058        for (eni = NULL, i = 0; i < ni->nr_extents; ++i) {
1059                if (mft_no == extent_nis[i]->mft_no) {
1060                        /*
1061                         * Found the extent inode corresponding to this extent
1062                         * mft record.
1063                         */
1064                        eni = extent_nis[i];
1065                        break;
1066                }
1067        }
1068        /*
1069         * If the extent inode was not attached to the base inode, write this
1070         * extent mft record.
1071         */
1072        if (!eni) {
1073                mutex_unlock(&ni->extent_lock);
1074                iput(vi);
1075                ntfs_debug("Extent inode 0x%lx is not attached to its base "
1076                                "inode 0x%lx, write the extent record.",
1077                                mft_no, na.mft_no);
1078                return true;
1079        }
1080        ntfs_debug("Extent inode 0x%lx is attached to its base inode 0x%lx.",
1081                        mft_no, na.mft_no);
1082        /* Take a reference to the extent ntfs inode. */
1083        atomic_inc(&eni->count);
1084        mutex_unlock(&ni->extent_lock);
1085        /*
1086         * Found the extent inode coresponding to this extent mft record.
1087         * Try to take the mft record lock.
1088         */
1089        if (unlikely(!mutex_trylock(&eni->mrec_lock))) {
1090                atomic_dec(&eni->count);
1091                iput(vi);
1092                ntfs_debug("Extent mft record 0x%lx is already locked, do "
1093                                "not write it.", mft_no);
1094                return false;
1095        }
1096        ntfs_debug("Managed to lock extent mft record 0x%lx, write it.",
1097                        mft_no);
1098        if (NInoTestClearDirty(eni))
1099                ntfs_debug("Extent inode 0x%lx is dirty, marking it clean.",
1100                                mft_no);
1101        /*
1102         * The write has to occur while we hold the mft record lock so return
1103         * the locked extent ntfs inode.
1104         */
1105        *locked_ni = eni;
1106        return true;
1107}
1108
1109static const char *es = "  Leaving inconsistent metadata.  Unmount and run "
1110                "chkdsk.";
1111
1112/**
1113 * ntfs_mft_bitmap_find_and_alloc_free_rec_nolock - see name
1114 * @vol:        volume on which to search for a free mft record
1115 * @base_ni:    open base inode if allocating an extent mft record or NULL
1116 *
1117 * Search for a free mft record in the mft bitmap attribute on the ntfs volume
1118 * @vol.
1119 *
1120 * If @base_ni is NULL start the search at the default allocator position.
1121 *
1122 * If @base_ni is not NULL start the search at the mft record after the base
1123 * mft record @base_ni.
1124 *
1125 * Return the free mft record on success and -errno on error.  An error code of
1126 * -ENOSPC means that there are no free mft records in the currently
1127 * initialized mft bitmap.
1128 *
1129 * Locking: Caller must hold vol->mftbmp_lock for writing.
1130 */
1131static int ntfs_mft_bitmap_find_and_alloc_free_rec_nolock(ntfs_volume *vol,
1132                ntfs_inode *base_ni)
1133{
1134        s64 pass_end, ll, data_pos, pass_start, ofs, bit;
1135        unsigned long flags;
1136        struct address_space *mftbmp_mapping;
1137        u8 *buf, *byte;
1138        struct page *page;
1139        unsigned int page_ofs, size;
1140        u8 pass, b;
1141
1142        ntfs_debug("Searching for free mft record in the currently "
1143                        "initialized mft bitmap.");
1144        mftbmp_mapping = vol->mftbmp_ino->i_mapping;
1145        /*
1146         * Set the end of the pass making sure we do not overflow the mft
1147         * bitmap.
1148         */
1149        read_lock_irqsave(&NTFS_I(vol->mft_ino)->size_lock, flags);
1150        pass_end = NTFS_I(vol->mft_ino)->allocated_size >>
1151                        vol->mft_record_size_bits;
1152        read_unlock_irqrestore(&NTFS_I(vol->mft_ino)->size_lock, flags);
1153        read_lock_irqsave(&NTFS_I(vol->mftbmp_ino)->size_lock, flags);
1154        ll = NTFS_I(vol->mftbmp_ino)->initialized_size << 3;
1155        read_unlock_irqrestore(&NTFS_I(vol->mftbmp_ino)->size_lock, flags);
1156        if (pass_end > ll)
1157                pass_end = ll;
1158        pass = 1;
1159        if (!base_ni)
1160                data_pos = vol->mft_data_pos;
1161        else
1162                data_pos = base_ni->mft_no + 1;
1163        if (data_pos < 24)
1164                data_pos = 24;
1165        if (data_pos >= pass_end) {
1166                data_pos = 24;
1167                pass = 2;
1168                /* This happens on a freshly formatted volume. */
1169                if (data_pos >= pass_end)
1170                        return -ENOSPC;
1171        }
1172        pass_start = data_pos;
1173        ntfs_debug("Starting bitmap search: pass %u, pass_start 0x%llx, "
1174                        "pass_end 0x%llx, data_pos 0x%llx.", pass,
1175                        (long long)pass_start, (long long)pass_end,
1176                        (long long)data_pos);
1177        /* Loop until a free mft record is found. */
1178        for (; pass <= 2;) {
1179                /* Cap size to pass_end. */
1180                ofs = data_pos >> 3;
1181                page_ofs = ofs & ~PAGE_CACHE_MASK;
1182                size = PAGE_CACHE_SIZE - page_ofs;
1183                ll = ((pass_end + 7) >> 3) - ofs;
1184                if (size > ll)
1185                        size = ll;
1186                size <<= 3;
1187                /*
1188                 * If we are still within the active pass, search the next page
1189                 * for a zero bit.
1190                 */
1191                if (size) {
1192                        page = ntfs_map_page(mftbmp_mapping,
1193                                        ofs >> PAGE_CACHE_SHIFT);
1194                        if (IS_ERR(page)) {
1195                                ntfs_error(vol->sb, "Failed to read mft "
1196                                                "bitmap, aborting.");
1197                                return PTR_ERR(page);
1198                        }
1199                        buf = (u8*)page_address(page) + page_ofs;
1200                        bit = data_pos & 7;
1201                        data_pos &= ~7ull;
1202                        ntfs_debug("Before inner for loop: size 0x%x, "
1203                                        "data_pos 0x%llx, bit 0x%llx", size,
1204                                        (long long)data_pos, (long long)bit);
1205                        for (; bit < size && data_pos + bit < pass_end;
1206                                        bit &= ~7ull, bit += 8) {
1207                                byte = buf + (bit >> 3);
1208                                if (*byte == 0xff)
1209                                        continue;
1210                                b = ffz((unsigned long)*byte);
1211                                if (b < 8 && b >= (bit & 7)) {
1212                                        ll = data_pos + (bit & ~7ull) + b;
1213                                        if (unlikely(ll > (1ll << 32))) {
1214                                                ntfs_unmap_page(page);
1215                                                return -ENOSPC;
1216                                        }
1217                                        *byte |= 1 << b;
1218                                        flush_dcache_page(page);
1219                                        set_page_dirty(page);
1220                                        ntfs_unmap_page(page);
1221                                        ntfs_debug("Done.  (Found and "
1222                                                        "allocated mft record "
1223                                                        "0x%llx.)",
1224                                                        (long long)ll);
1225                                        return ll;
1226                                }
1227                        }
1228                        ntfs_debug("After inner for loop: size 0x%x, "
1229                                        "data_pos 0x%llx, bit 0x%llx", size,
1230                                        (long long)data_pos, (long long)bit);
1231                        data_pos += size;
1232                        ntfs_unmap_page(page);
1233                        /*
1234                         * If the end of the pass has not been reached yet,
1235                         * continue searching the mft bitmap for a zero bit.
1236                         */
1237                        if (data_pos < pass_end)
1238                                continue;
1239                }
1240                /* Do the next pass. */
1241                if (++pass == 2) {
1242                        /*
1243                         * Starting the second pass, in which we scan the first
1244                         * part of the zone which we omitted earlier.
1245                         */
1246                        pass_end = pass_start;
1247                        data_pos = pass_start = 24;
1248                        ntfs_debug("pass %i, pass_start 0x%llx, pass_end "
1249                                        "0x%llx.", pass, (long long)pass_start,
1250                                        (long long)pass_end);
1251                        if (data_pos >= pass_end)
1252                                break;
1253                }
1254        }
1255        /* No free mft records in currently initialized mft bitmap. */
1256        ntfs_debug("Done.  (No free mft records left in currently initialized "
1257                        "mft bitmap.)");
1258        return -ENOSPC;
1259}
1260
1261/**
1262 * ntfs_mft_bitmap_extend_allocation_nolock - extend mft bitmap by a cluster
1263 * @vol:        volume on which to extend the mft bitmap attribute
1264 *
1265 * Extend the mft bitmap attribute on the ntfs volume @vol by one cluster.
1266 *
1267 * Note: Only changes allocated_size, i.e. does not touch initialized_size or
1268 * data_size.
1269 *
1270 * Return 0 on success and -errno on error.
1271 *
1272 * Locking: - Caller must hold vol->mftbmp_lock for writing.
1273 *          - This function takes NTFS_I(vol->mftbmp_ino)->runlist.lock for
1274 *            writing and releases it before returning.
1275 *          - This function takes vol->lcnbmp_lock for writing and releases it
1276 *            before returning.
1277 */
1278static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
1279{
1280        LCN lcn;
1281        s64 ll;
1282        unsigned long flags;
1283        struct page *page;
1284        ntfs_inode *mft_ni, *mftbmp_ni;
1285        runlist_element *rl, *rl2 = NULL;
1286        ntfs_attr_search_ctx *ctx = NULL;
1287        MFT_RECORD *mrec;
1288        ATTR_RECORD *a = NULL;
1289        int ret, mp_size;
1290        u32 old_alen = 0;
1291        u8 *b, tb;
1292        struct {
1293                u8 added_cluster:1;
1294                u8 added_run:1;
1295                u8 mp_rebuilt:1;
1296        } status = { 0, 0, 0 };
1297
1298        ntfs_debug("Extending mft bitmap allocation.");
1299        mft_ni = NTFS_I(vol->mft_ino);
1300        mftbmp_ni = NTFS_I(vol->mftbmp_ino);
1301        /*
1302         * Determine the last lcn of the mft bitmap.  The allocated size of the
1303         * mft bitmap cannot be zero so we are ok to do this.
1304         */
1305        down_write(&mftbmp_ni->runlist.lock);
1306        read_lock_irqsave(&mftbmp_ni->size_lock, flags);
1307        ll = mftbmp_ni->allocated_size;
1308        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1309        rl = ntfs_attr_find_vcn_nolock(mftbmp_ni,
1310                        (ll - 1) >> vol->cluster_size_bits, NULL);
1311        if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
1312                up_write(&mftbmp_ni->runlist.lock);
1313                ntfs_error(vol->sb, "Failed to determine last allocated "
1314                                "cluster of mft bitmap attribute.");
1315                if (!IS_ERR(rl))
1316                        ret = -EIO;
1317                else
1318                        ret = PTR_ERR(rl);
1319                return ret;
1320        }
1321        lcn = rl->lcn + rl->length;
1322        ntfs_debug("Last lcn of mft bitmap attribute is 0x%llx.",
1323                        (long long)lcn);
1324        /*
1325         * Attempt to get the cluster following the last allocated cluster by
1326         * hand as it may be in the MFT zone so the allocator would not give it
1327         * to us.
1328         */
1329        ll = lcn >> 3;
1330        page = ntfs_map_page(vol->lcnbmp_ino->i_mapping,
1331                        ll >> PAGE_CACHE_SHIFT);
1332        if (IS_ERR(page)) {
1333                up_write(&mftbmp_ni->runlist.lock);
1334                ntfs_error(vol->sb, "Failed to read from lcn bitmap.");
1335                return PTR_ERR(page);
1336        }
1337        b = (u8*)page_address(page) + (ll & ~PAGE_CACHE_MASK);
1338        tb = 1 << (lcn & 7ull);
1339        down_write(&vol->lcnbmp_lock);
1340        if (*b != 0xff && !(*b & tb)) {
1341                /* Next cluster is free, allocate it. */
1342                *b |= tb;
1343                flush_dcache_page(page);
1344                set_page_dirty(page);
1345                up_write(&vol->lcnbmp_lock);
1346                ntfs_unmap_page(page);
1347                /* Update the mft bitmap runlist. */
1348                rl->length++;
1349                rl[1].vcn++;
1350                status.added_cluster = 1;
1351                ntfs_debug("Appending one cluster to mft bitmap.");
1352        } else {
1353                up_write(&vol->lcnbmp_lock);
1354                ntfs_unmap_page(page);
1355                /* Allocate a cluster from the DATA_ZONE. */
1356                rl2 = ntfs_cluster_alloc(vol, rl[1].vcn, 1, lcn, DATA_ZONE,
1357                                true);
1358                if (IS_ERR(rl2)) {
1359                        up_write(&mftbmp_ni->runlist.lock);
1360                        ntfs_error(vol->sb, "Failed to allocate a cluster for "
1361                                        "the mft bitmap.");
1362                        return PTR_ERR(rl2);
1363                }
1364                rl = ntfs_runlists_merge(mftbmp_ni->runlist.rl, rl2);
1365                if (IS_ERR(rl)) {
1366                        up_write(&mftbmp_ni->runlist.lock);
1367                        ntfs_error(vol->sb, "Failed to merge runlists for mft "
1368                                        "bitmap.");
1369                        if (ntfs_cluster_free_from_rl(vol, rl2)) {
1370                                ntfs_error(vol->sb, "Failed to deallocate "
1371                                                "allocated cluster.%s", es);
1372                                NVolSetErrors(vol);
1373                        }
1374                        ntfs_free(rl2);
1375                        return PTR_ERR(rl);
1376                }
1377                mftbmp_ni->runlist.rl = rl;
1378                status.added_run = 1;
1379                ntfs_debug("Adding one run to mft bitmap.");
1380                /* Find the last run in the new runlist. */
1381                for (; rl[1].length; rl++)
1382                        ;
1383        }
1384        /*
1385         * Update the attribute record as well.  Note: @rl is the last
1386         * (non-terminator) runlist element of mft bitmap.
1387         */
1388        mrec = map_mft_record(mft_ni);
1389        if (IS_ERR(mrec)) {
1390                ntfs_error(vol->sb, "Failed to map mft record.");
1391                ret = PTR_ERR(mrec);
1392                goto undo_alloc;
1393        }
1394        ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1395        if (unlikely(!ctx)) {
1396                ntfs_error(vol->sb, "Failed to get search context.");
1397                ret = -ENOMEM;
1398                goto undo_alloc;
1399        }
1400        ret = ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1401                        mftbmp_ni->name_len, CASE_SENSITIVE, rl[1].vcn, NULL,
1402                        0, ctx);
1403        if (unlikely(ret)) {
1404                ntfs_error(vol->sb, "Failed to find last attribute extent of "
1405                                "mft bitmap attribute.");
1406                if (ret == -ENOENT)
1407                        ret = -EIO;
1408                goto undo_alloc;
1409        }
1410        a = ctx->attr;
1411        ll = sle64_to_cpu(a->data.non_resident.lowest_vcn);
1412        /* Search back for the previous last allocated cluster of mft bitmap. */
1413        for (rl2 = rl; rl2 > mftbmp_ni->runlist.rl; rl2--) {
1414                if (ll >= rl2->vcn)
1415                        break;
1416        }
1417        BUG_ON(ll < rl2->vcn);
1418        BUG_ON(ll >= rl2->vcn + rl2->length);
1419        /* Get the size for the new mapping pairs array for this extent. */
1420        mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
1421        if (unlikely(mp_size <= 0)) {
1422                ntfs_error(vol->sb, "Get size for mapping pairs failed for "
1423                                "mft bitmap attribute extent.");
1424                ret = mp_size;
1425                if (!ret)
1426                        ret = -EIO;
1427                goto undo_alloc;
1428        }
1429        /* Expand the attribute record if necessary. */
1430        old_alen = le32_to_cpu(a->length);
1431        ret = ntfs_attr_record_resize(ctx->mrec, a, mp_size +
1432                        le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
1433        if (unlikely(ret)) {
1434                if (ret != -ENOSPC) {
1435                        ntfs_error(vol->sb, "Failed to resize attribute "
1436                                        "record for mft bitmap attribute.");
1437                        goto undo_alloc;
1438                }
1439                // TODO: Deal with this by moving this extent to a new mft
1440                // record or by starting a new extent in a new mft record or by
1441                // moving other attributes out of this mft record.
1442                // Note: It will need to be a special mft record and if none of
1443                // those are available it gets rather complicated...
1444                ntfs_error(vol->sb, "Not enough space in this mft record to "
1445                                "accommodate extended mft bitmap attribute "
1446                                "extent.  Cannot handle this yet.");
1447                ret = -EOPNOTSUPP;
1448                goto undo_alloc;
1449        }
1450        status.mp_rebuilt = 1;
1451        /* Generate the mapping pairs array directly into the attr record. */
1452        ret = ntfs_mapping_pairs_build(vol, (u8*)a +
1453                        le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
1454                        mp_size, rl2, ll, -1, NULL);
1455        if (unlikely(ret)) {
1456                ntfs_error(vol->sb, "Failed to build mapping pairs array for "
1457                                "mft bitmap attribute.");
1458                goto undo_alloc;
1459        }
1460        /* Update the highest_vcn. */
1461        a->data.non_resident.highest_vcn = cpu_to_sle64(rl[1].vcn - 1);
1462        /*
1463         * We now have extended the mft bitmap allocated_size by one cluster.
1464         * Reflect this in the ntfs_inode structure and the attribute record.
1465         */
1466        if (a->data.non_resident.lowest_vcn) {
1467                /*
1468                 * We are not in the first attribute extent, switch to it, but
1469                 * first ensure the changes will make it to disk later.
1470                 */
1471                flush_dcache_mft_record_page(ctx->ntfs_ino);
1472                mark_mft_record_dirty(ctx->ntfs_ino);
1473                ntfs_attr_reinit_search_ctx(ctx);
1474                ret = ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1475                                mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL,
1476                                0, ctx);
1477                if (unlikely(ret)) {
1478                        ntfs_error(vol->sb, "Failed to find first attribute "
1479                                        "extent of mft bitmap attribute.");
1480                        goto restore_undo_alloc;
1481                }
1482                a = ctx->attr;
1483        }
1484        write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1485        mftbmp_ni->allocated_size += vol->cluster_size;
1486        a->data.non_resident.allocated_size =
1487                        cpu_to_sle64(mftbmp_ni->allocated_size);
1488        write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1489        /* Ensure the changes make it to disk. */
1490        flush_dcache_mft_record_page(ctx->ntfs_ino);
1491        mark_mft_record_dirty(ctx->ntfs_ino);
1492        ntfs_attr_put_search_ctx(ctx);
1493        unmap_mft_record(mft_ni);
1494        up_write(&mftbmp_ni->runlist.lock);
1495        ntfs_debug("Done.");
1496        return 0;
1497restore_undo_alloc:
1498        ntfs_attr_reinit_search_ctx(ctx);
1499        if (ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1500                        mftbmp_ni->name_len, CASE_SENSITIVE, rl[1].vcn, NULL,
1501                        0, ctx)) {
1502                ntfs_error(vol->sb, "Failed to find last attribute extent of "
1503                                "mft bitmap attribute.%s", es);
1504                write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1505                mftbmp_ni->allocated_size += vol->cluster_size;
1506                write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1507                ntfs_attr_put_search_ctx(ctx);
1508                unmap_mft_record(mft_ni);
1509                up_write(&mftbmp_ni->runlist.lock);
1510                /*
1511                 * The only thing that is now wrong is ->allocated_size of the
1512                 * base attribute extent which chkdsk should be able to fix.
1513                 */
1514                NVolSetErrors(vol);
1515                return ret;
1516        }
1517        a = ctx->attr;
1518        a->data.non_resident.highest_vcn = cpu_to_sle64(rl[1].vcn - 2);
1519undo_alloc:
1520        if (status.added_cluster) {
1521                /* Truncate the last run in the runlist by one cluster. */
1522                rl->length--;
1523                rl[1].vcn--;
1524        } else if (status.added_run) {
1525                lcn = rl->lcn;
1526                /* Remove the last run from the runlist. */
1527                rl->lcn = rl[1].lcn;
1528                rl->length = 0;
1529        }
1530        /* Deallocate the cluster. */
1531        down_write(&vol->lcnbmp_lock);
1532        if (ntfs_bitmap_clear_bit(vol->lcnbmp_ino, lcn)) {
1533                ntfs_error(vol->sb, "Failed to free allocated cluster.%s", es);
1534                NVolSetErrors(vol);
1535        }
1536        up_write(&vol->lcnbmp_lock);
1537        if (status.mp_rebuilt) {
1538                if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
1539                                a->data.non_resident.mapping_pairs_offset),
1540                                old_alen - le16_to_cpu(
1541                                a->data.non_resident.mapping_pairs_offset),
1542                                rl2, ll, -1, NULL)) {
1543                        ntfs_error(vol->sb, "Failed to restore mapping pairs "
1544                                        "array.%s", es);
1545                        NVolSetErrors(vol);
1546                }
1547                if (ntfs_attr_record_resize(ctx->mrec, a, old_alen)) {
1548                        ntfs_error(vol->sb, "Failed to restore attribute "
1549                                        "record.%s", es);
1550                        NVolSetErrors(vol);
1551                }
1552                flush_dcache_mft_record_page(ctx->ntfs_ino);
1553                mark_mft_record_dirty(ctx->ntfs_ino);
1554        }
1555        if (ctx)
1556                ntfs_attr_put_search_ctx(ctx);
1557        if (!IS_ERR(mrec))
1558                unmap_mft_record(mft_ni);
1559        up_write(&mftbmp_ni->runlist.lock);
1560        return ret;
1561}
1562
1563/**
1564 * ntfs_mft_bitmap_extend_initialized_nolock - extend mftbmp initialized data
1565 * @vol:        volume on which to extend the mft bitmap attribute
1566 *
1567 * Extend the initialized portion of the mft bitmap attribute on the ntfs
1568 * volume @vol by 8 bytes.
1569 *
1570 * Note:  Only changes initialized_size and data_size, i.e. requires that
1571 * allocated_size is big enough to fit the new initialized_size.
1572 *
1573 * Return 0 on success and -error on error.
1574 *
1575 * Locking: Caller must hold vol->mftbmp_lock for writing.
1576 */
1577static int ntfs_mft_bitmap_extend_initialized_nolock(ntfs_volume *vol)
1578{
1579        s64 old_data_size, old_initialized_size;
1580        unsigned long flags;
1581        struct inode *mftbmp_vi;
1582        ntfs_inode *mft_ni, *mftbmp_ni;
1583        ntfs_attr_search_ctx *ctx;
1584        MFT_RECORD *mrec;
1585        ATTR_RECORD *a;
1586        int ret;
1587
1588        ntfs_debug("Extending mft bitmap initiailized (and data) size.");
1589        mft_ni = NTFS_I(vol->mft_ino);
1590        mftbmp_vi = vol->mftbmp_ino;
1591        mftbmp_ni = NTFS_I(mftbmp_vi);
1592        /* Get the attribute record. */
1593        mrec = map_mft_record(mft_ni);
1594        if (IS_ERR(mrec)) {
1595                ntfs_error(vol->sb, "Failed to map mft record.");
1596                return PTR_ERR(mrec);
1597        }
1598        ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1599        if (unlikely(!ctx)) {
1600                ntfs_error(vol->sb, "Failed to get search context.");
1601                ret = -ENOMEM;
1602                goto unm_err_out;
1603        }
1604        ret = ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1605                        mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL, 0, ctx);
1606        if (unlikely(ret)) {
1607                ntfs_error(vol->sb, "Failed to find first attribute extent of "
1608                                "mft bitmap attribute.");
1609                if (ret == -ENOENT)
1610                        ret = -EIO;
1611                goto put_err_out;
1612        }
1613        a = ctx->attr;
1614        write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1615        old_data_size = i_size_read(mftbmp_vi);
1616        old_initialized_size = mftbmp_ni->initialized_size;
1617        /*
1618         * We can simply update the initialized_size before filling the space
1619         * with zeroes because the caller is holding the mft bitmap lock for
1620         * writing which ensures that no one else is trying to access the data.
1621         */
1622        mftbmp_ni->initialized_size += 8;
1623        a->data.non_resident.initialized_size =
1624                        cpu_to_sle64(mftbmp_ni->initialized_size);
1625        if (mftbmp_ni->initialized_size > old_data_size) {
1626                i_size_write(mftbmp_vi, mftbmp_ni->initialized_size);
1627                a->data.non_resident.data_size =
1628                                cpu_to_sle64(mftbmp_ni->initialized_size);
1629        }
1630        write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1631        /* Ensure the changes make it to disk. */
1632        flush_dcache_mft_record_page(ctx->ntfs_ino);
1633        mark_mft_record_dirty(ctx->ntfs_ino);
1634        ntfs_attr_put_search_ctx(ctx);
1635        unmap_mft_record(mft_ni);
1636        /* Initialize the mft bitmap attribute value with zeroes. */
1637        ret = ntfs_attr_set(mftbmp_ni, old_initialized_size, 8, 0);
1638        if (likely(!ret)) {
1639                ntfs_debug("Done.  (Wrote eight initialized bytes to mft "
1640                                "bitmap.");
1641                return 0;
1642        }
1643        ntfs_error(vol->sb, "Failed to write to mft bitmap.");
1644        /* Try to recover from the error. */
1645        mrec = map_mft_record(mft_ni);
1646        if (IS_ERR(mrec)) {
1647                ntfs_error(vol->sb, "Failed to map mft record.%s", es);
1648                NVolSetErrors(vol);
1649                return ret;
1650        }
1651        ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1652        if (unlikely(!ctx)) {
1653                ntfs_error(vol->sb, "Failed to get search context.%s", es);
1654                NVolSetErrors(vol);
1655                goto unm_err_out;
1656        }
1657        if (ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1658                        mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL, 0, ctx)) {
1659                ntfs_error(vol->sb, "Failed to find first attribute extent of "
1660                                "mft bitmap attribute.%s", es);
1661                NVolSetErrors(vol);
1662put_err_out:
1663                ntfs_attr_put_search_ctx(ctx);
1664unm_err_out:
1665                unmap_mft_record(mft_ni);
1666                goto err_out;
1667        }
1668        a = ctx->attr;
1669        write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1670        mftbmp_ni->initialized_size = old_initialized_size;
1671        a->data.non_resident.initialized_size =
1672                        cpu_to_sle64(old_initialized_size);
1673        if (i_size_read(mftbmp_vi) != old_data_size) {
1674                i_size_write(mftbmp_vi, old_data_size);
1675                a->data.non_resident.data_size = cpu_to_sle64(old_data_size);
1676        }
1677        write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1678        flush_dcache_mft_record_page(ctx->ntfs_ino);
1679        mark_mft_record_dirty(ctx->ntfs_ino);
1680        ntfs_attr_put_search_ctx(ctx);
1681        unmap_mft_record(mft_ni);
1682#ifdef DEBUG
1683        read_lock_irqsave(&mftbmp_ni->size_lock, flags);
1684        ntfs_debug("Restored status of mftbmp: allocated_size 0x%llx, "
1685                        "data_size 0x%llx, initialized_size 0x%llx.",
1686                        (long long)mftbmp_ni->allocated_size,
1687                        (long long)i_size_read(mftbmp_vi),
1688                        (long long)mftbmp_ni->initialized_size);
1689        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1690#endif /* DEBUG */
1691err_out:
1692        return ret;
1693}
1694
1695/**
1696 * ntfs_mft_data_extend_allocation_nolock - extend mft data attribute
1697 * @vol:        volume on which to extend the mft data attribute
1698 *
1699 * Extend the mft data attribute on the ntfs volume @vol by 16 mft records
1700 * worth of clusters or if not enough space for this by one mft record worth
1701 * of clusters.
1702 *
1703 * Note:  Only changes allocated_size, i.e. does not touch initialized_size or
1704 * data_size.
1705 *
1706 * Return 0 on success and -errno on error.
1707 *
1708 * Locking: - Caller must hold vol->mftbmp_lock for writing.
1709 *          - This function takes NTFS_I(vol->mft_ino)->runlist.lock for
1710 *            writing and releases it before returning.
1711 *          - This function calls functions which take vol->lcnbmp_lock for
1712 *            writing and release it before returning.
1713 */
1714static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
1715{
1716        LCN lcn;
1717        VCN old_last_vcn;
1718        s64 min_nr, nr, ll;
1719        unsigned long flags;
1720        ntfs_inode *mft_ni;
1721        runlist_element *rl, *rl2;
1722        ntfs_attr_search_ctx *ctx = NULL;
1723        MFT_RECORD *mrec;
1724        ATTR_RECORD *a = NULL;
1725        int ret, mp_size;
1726        u32 old_alen = 0;
1727        bool mp_rebuilt = false;
1728
1729        ntfs_debug("Extending mft data allocation.");
1730        mft_ni = NTFS_I(vol->mft_ino);
1731        /*
1732         * Determine the preferred allocation location, i.e. the last lcn of
1733         * the mft data attribute.  The allocated size of the mft data
1734         * attribute cannot be zero so we are ok to do this.
1735         */
1736        down_write(&mft_ni->runlist.lock);
1737        read_lock_irqsave(&mft_ni->size_lock, flags);
1738        ll = mft_ni->allocated_size;
1739        read_unlock_irqrestore(&mft_ni->size_lock, flags);
1740        rl = ntfs_attr_find_vcn_nolock(mft_ni,
1741                        (ll - 1) >> vol->cluster_size_bits, NULL);
1742        if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
1743                up_write(&mft_ni->runlist.lock);
1744                ntfs_error(vol->sb, "Failed to determine last allocated "
1745                                "cluster of mft data attribute.");
1746                if (!IS_ERR(rl))
1747                        ret = -EIO;
1748                else
1749                        ret = PTR_ERR(rl);
1750                return ret;
1751        }
1752        lcn = rl->lcn + rl->length;
1753        ntfs_debug("Last lcn of mft data attribute is 0x%llx.", (long long)lcn);
1754        /* Minimum allocation is one mft record worth of clusters. */
1755        min_nr = vol->mft_record_size >> vol->cluster_size_bits;
1756        if (!min_nr)
1757                min_nr = 1;
1758        /* Want to allocate 16 mft records worth of clusters. */
1759        nr = vol->mft_record_size << 4 >> vol->cluster_size_bits;
1760        if (!nr)
1761                nr = min_nr;
1762        /* Ensure we do not go above 2^32-1 mft records. */
1763        read_lock_irqsave(&mft_ni->size_lock, flags);
1764        ll = mft_ni->allocated_size;
1765        read_unlock_irqrestore(&mft_ni->size_lock, flags);
1766        if (unlikely((ll + (nr << vol->cluster_size_bits)) >>
1767                        vol->mft_record_size_bits >= (1ll << 32))) {
1768                nr = min_nr;
1769                if (unlikely((ll + (nr << vol->cluster_size_bits)) >>
1770                                vol->mft_record_size_bits >= (1ll << 32))) {
1771                        ntfs_warning(vol->sb, "Cannot allocate mft record "
1772                                        "because the maximum number of inodes "
1773                                        "(2^32) has already been reached.");
1774                        up_write(&mft_ni->runlist.lock);
1775                        return -ENOSPC;
1776                }
1777        }
1778        ntfs_debug("Trying mft data allocation with %s cluster count %lli.",
1779                        nr > min_nr ? "default" : "minimal", (long long)nr);
1780        old_last_vcn = rl[1].vcn;
1781        do {
1782                rl2 = ntfs_cluster_alloc(vol, old_last_vcn, nr, lcn, MFT_ZONE,
1783                                true);
1784                if (likely(!IS_ERR(rl2)))
1785                        break;
1786                if (PTR_ERR(rl2) != -ENOSPC || nr == min_nr) {
1787                        ntfs_error(vol->sb, "Failed to allocate the minimal "
1788                                        "number of clusters (%lli) for the "
1789                                        "mft data attribute.", (long long)nr);
1790                        up_write(&mft_ni->runlist.lock);
1791                        return PTR_ERR(rl2);
1792                }
1793                /*
1794                 * There is not enough space to do the allocation, but there
1795                 * might be enough space to do a minimal allocation so try that
1796                 * before failing.
1797                 */
1798                nr = min_nr;
1799                ntfs_debug("Retrying mft data allocation with minimal cluster "
1800                                "count %lli.", (long long)nr);
1801        } while (1);
1802        rl = ntfs_runlists_merge(mft_ni->runlist.rl, rl2);
1803        if (IS_ERR(rl)) {
1804                up_write(&mft_ni->runlist.lock);
1805                ntfs_error(vol->sb, "Failed to merge runlists for mft data "
1806                                "attribute.");
1807                if (ntfs_cluster_free_from_rl(vol, rl2)) {
1808                        ntfs_error(vol->sb, "Failed to deallocate clusters "
1809                                        "from the mft data attribute.%s", es);
1810                        NVolSetErrors(vol);
1811                }
1812                ntfs_free(rl2);
1813                return PTR_ERR(rl);
1814        }
1815        mft_ni->runlist.rl = rl;
1816        ntfs_debug("Allocated %lli clusters.", (long long)nr);
1817        /* Find the last run in the new runlist. */
1818        for (; rl[1].length; rl++)
1819                ;
1820        /* Update the attribute record as well. */
1821        mrec = map_mft_record(mft_ni);
1822        if (IS_ERR(mrec)) {
1823                ntfs_error(vol->sb, "Failed to map mft record.");
1824                ret = PTR_ERR(mrec);
1825                goto undo_alloc;
1826        }
1827        ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1828        if (unlikely(!ctx)) {
1829                ntfs_error(vol->sb, "Failed to get search context.");
1830                ret = -ENOMEM;
1831                goto undo_alloc;
1832        }
1833        ret = ntfs_attr_lookup(mft_ni->type, mft_ni->name, mft_ni->name_len,
1834                        CASE_SENSITIVE, rl[1].vcn, NULL, 0, ctx);
1835        if (unlikely(ret)) {
1836                ntfs_error(vol->sb, "Failed to find last attribute extent of "
1837                                "mft data attribute.");
1838                if (ret == -ENOENT)
1839                        ret = -EIO;
1840                goto undo_alloc;
1841        }
1842        a = ctx->attr;
1843        ll = sle64_to_cpu(a->data.non_resident.lowest_vcn);
1844        /* Search back for the previous last allocated cluster of mft bitmap. */
1845        for (rl2 = rl; rl2 > mft_ni->runlist.rl; rl2--) {
1846                if (ll >= rl2->vcn)
1847                        break;
1848        }
1849        BUG_ON(ll < rl2->vcn);
1850        BUG_ON(ll >= rl2->vcn + rl2->length);
1851        /* Get the size for the new mapping pairs array for this extent. */
1852        mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
1853        if (unlikely(mp_size <= 0)) {
1854                ntfs_error(vol->sb, "Get size for mapping pairs failed for "
1855                                "mft data attribute extent.");
1856                ret = mp_size;
1857                if (!ret)
1858                        ret = -EIO;
1859                goto undo_alloc;
1860        }
1861        /* Expand the attribute record if necessary. */
1862        old_alen = le32_to_cpu(a->length);
1863        ret = ntfs_attr_record_resize(ctx->mrec, a, mp_size +
1864                        le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
1865        if (unlikely(ret)) {
1866                if (ret != -ENOSPC) {
1867                        ntfs_error(vol->sb, "Failed to resize attribute "
1868                                        "record for mft data attribute.");
1869                        goto undo_alloc;
1870                }
1871                // TODO: Deal with this by moving this extent to a new mft
1872                // record or by starting a new extent in a new mft record or by
1873                // moving other attributes out of this mft record.
1874                // Note: Use the special reserved mft records and ensure that
1875                // this extent is not required to find the mft record in
1876                // question.  If no free special records left we would need to
1877                // move an existing record away, insert ours in its place, and
1878                // then place the moved record into the newly allocated space
1879                // and we would then need to update all references to this mft
1880                // record appropriately.  This is rather complicated...
1881                ntfs_error(vol->sb, "Not enough space in this mft record to "
1882                                "accommodate extended mft data attribute "
1883                                "extent.  Cannot handle this yet.");
1884                ret = -EOPNOTSUPP;
1885                goto undo_alloc;
1886        }
1887        mp_rebuilt = true;
1888        /* Generate the mapping pairs array directly into the attr record. */
1889        ret = ntfs_mapping_pairs_build(vol, (u8*)a +
1890                        le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
1891                        mp_size, rl2, ll, -1, NULL);
1892        if (unlikely(ret)) {
1893                ntfs_error(vol->sb, "Failed to build mapping pairs array of "
1894                                "mft data attribute.");
1895                goto undo_alloc;
1896        }
1897        /* Update the highest_vcn. */
1898        a->data.non_resident.highest_vcn = cpu_to_sle64(rl[1].vcn - 1);
1899        /*
1900         * We now have extended the mft data allocated_size by nr clusters.
1901         * Reflect this in the ntfs_inode structure and the attribute record.
1902         * @rl is the last (non-terminator) runlist element of mft data
1903         * attribute.
1904         */
1905        if (a->data.non_resident.lowest_vcn) {
1906                /*
1907                 * We are not in the first attribute extent, switch to it, but
1908                 * first ensure the changes will make it to disk later.
1909                 */
1910                flush_dcache_mft_record_page(ctx->ntfs_ino);
1911                mark_mft_record_dirty(ctx->ntfs_ino);
1912                ntfs_attr_reinit_search_ctx(ctx);
1913                ret = ntfs_attr_lookup(mft_ni->type, mft_ni->name,
1914                                mft_ni->name_len, CASE_SENSITIVE, 0, NULL, 0,
1915                                ctx);
1916                if (unlikely(ret)) {
1917                        ntfs_error(vol->sb, "Failed to find first attribute "
1918                                        "extent of mft data attribute.");
1919                        goto restore_undo_alloc;
1920                }
1921                a = ctx->attr;
1922        }
1923        write_lock_irqsave(&mft_ni->size_lock, flags);
1924        mft_ni->allocated_size += nr << vol->cluster_size_bits;
1925        a->data.non_resident.allocated_size =
1926                        cpu_to_sle64(mft_ni->allocated_size);
1927        write_unlock_irqrestore(&mft_ni->size_lock, flags);
1928        /* Ensure the changes make it to disk. */
1929        flush_dcache_mft_record_page(ctx->ntfs_ino);
1930        mark_mft_record_dirty(ctx->ntfs_ino);
1931        ntfs_attr_put_search_ctx(ctx);
1932        unmap_mft_record(mft_ni);
1933        up_write(&mft_ni->runlist.lock);
1934        ntfs_debug("Done.");
1935        return 0;
1936restore_undo_alloc:
1937        ntfs_attr_reinit_search_ctx(ctx);
1938        if (ntfs_attr_lookup(mft_ni->type, mft_ni->name, mft_ni->name_len,
1939                        CASE_SENSITIVE, rl[1].vcn, NULL, 0, ctx)) {
1940                ntfs_error(vol->sb, "Failed to find last attribute extent of "
1941                                "mft data attribute.%s", es);
1942                write_lock_irqsave(&mft_ni->size_lock, flags);
1943                mft_ni->allocated_size += nr << vol->cluster_size_bits;
1944                write_unlock_irqrestore(&mft_ni->size_lock, flags);
1945                ntfs_attr_put_search_ctx(ctx);
1946                unmap_mft_record(mft_ni);
1947                up_write(&mft_ni->runlist.lock);
1948                /*
1949                 * The only thing that is now wrong is ->allocated_size of the
1950                 * base attribute extent which chkdsk should be able to fix.
1951                 */
1952                NVolSetErrors(vol);
1953                return ret;
1954        }
1955        ctx->attr->data.non_resident.highest_vcn =
1956                        cpu_to_sle64(old_last_vcn - 1);
1957undo_alloc:
1958        if (ntfs_cluster_free(mft_ni, old_last_vcn, -1, ctx) < 0) {
1959                ntfs_error(vol->sb, "Failed to free clusters from mft data "
1960                                "attribute.%s", es);
1961                NVolSetErrors(vol);
1962        }
1963        a = ctx->attr;
1964        if (ntfs_rl_truncate_nolock(vol, &mft_ni->runlist, old_last_vcn)) {
1965                ntfs_error(vol->sb, "Failed to truncate mft data attribute "
1966                                "runlist.%s", es);
1967                NVolSetErrors(vol);
1968        }
1969        if (mp_rebuilt && !IS_ERR(ctx->mrec)) {
1970                if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
1971                                a->data.non_resident.mapping_pairs_offset),
1972                                old_alen - le16_to_cpu(
1973                                a->data.non_resident.mapping_pairs_offset),
1974                                rl2, ll, -1, NULL)) {
1975                        ntfs_error(vol->sb, "Failed to restore mapping pairs "
1976                                        "array.%s", es);
1977                        NVolSetErrors(vol);
1978                }
1979                if (ntfs_attr_record_resize(ctx->mrec, a, old_alen)) {
1980                        ntfs_error(vol->sb, "Failed to restore attribute "
1981                                        "record.%s", es);
1982                        NVolSetErrors(vol);
1983                }
1984                flush_dcache_mft_record_page(ctx->ntfs_ino);
1985                mark_mft_record_dirty(ctx->ntfs_ino);
1986        } else if (IS_ERR(ctx->mrec)) {
1987                ntfs_error(vol->sb, "Failed to restore attribute search "
1988                                "context.%s", es);
1989                NVolSetErrors(vol);
1990        }
1991        if (ctx)
1992                ntfs_attr_put_search_ctx(ctx);
1993        if (!IS_ERR(mrec))
1994                unmap_mft_record(mft_ni);
1995        up_write(&mft_ni->runlist.lock);
1996        return ret;
1997}
1998
1999/**
2000 * ntfs_mft_record_layout - layout an mft record into a memory buffer
2001 * @vol:        volume to which the mft record will belong
2002 * @mft_no:     mft reference specifying the mft record number
2003 * @m:          destination buffer of size >= @vol->mft_record_size bytes
2004 *
2005 * Layout an empty, unused mft record with the mft record number @mft_no into
2006 * the buffer @m.  The volume @vol is needed because the mft record structure
2007 * was modified in NTFS 3.1 so we need to know which volume version this mft
2008 * record will be used on.
2009 *
2010 * Return 0 on success and -errno on error.
2011 */
2012static int ntfs_mft_record_layout(const ntfs_volume *vol, const s64 mft_no,
2013                MFT_RECORD *m)
2014{
2015        ATTR_RECORD *a;
2016
2017        ntfs_debug("Entering for mft record 0x%llx.", (long long)mft_no);
2018        if (mft_no >= (1ll << 32)) {
2019                ntfs_error(vol->sb, "Mft record number 0x%llx exceeds "
2020                                "maximum of 2^32.", (long long)mft_no);
2021                return -ERANGE;
2022        }
2023        /* Start by clearing the whole mft record to gives us a clean slate. */
2024        memset(m, 0, vol->mft_record_size);
2025        /* Aligned to 2-byte boundary. */
2026        if (vol->major_ver < 3 || (vol->major_ver == 3 && !vol->minor_ver))
2027                m->usa_ofs = cpu_to_le16((sizeof(MFT_RECORD_OLD) + 1) & ~1);
2028        else {
2029                m->usa_ofs = cpu_to_le16((sizeof(MFT_RECORD) + 1) & ~1);
2030                /*
2031                 * Set the NTFS 3.1+ specific fields while we know that the
2032                 * volume version is 3.1+.
2033                 */
2034                m->reserved = 0;
2035                m->mft_record_number = cpu_to_le32((u32)mft_no);
2036        }
2037        m->magic = magic_FILE;
2038        if (vol->mft_record_size >= NTFS_BLOCK_SIZE)
2039                m->usa_count = cpu_to_le16(vol->mft_record_size /
2040                                NTFS_BLOCK_SIZE + 1);
2041        else {
2042                m->usa_count = cpu_to_le16(1);
2043                ntfs_warning(vol->sb, "Sector size is bigger than mft record "
2044                                "size.  Setting usa_count to 1.  If chkdsk "
2045                                "reports this as corruption, please email "
2046                                "linux-ntfs-dev@lists.sourceforge.net stating "
2047                                "that you saw this message and that the "
2048                                "modified filesystem created was corrupt.  "
2049                                "Thank you.");
2050        }
2051        /* Set the update sequence number to 1. */
2052        *(le16*)((u8*)m + le16_to_cpu(m->usa_ofs)) = cpu_to_le16(1);
2053        m->lsn = 0;
2054        m->sequence_number = cpu_to_le16(1);
2055        m->link_count = 0;
2056        /*
2057         * Place the attributes straight after the update sequence array,
2058         * aligned to 8-byte boundary.
2059         */
2060        m->attrs_offset = cpu_to_le16((le16_to_cpu(m->usa_ofs) +
2061                        (le16_to_cpu(m->usa_count) << 1) + 7) & ~7);
2062        m->flags = 0;
2063        /*
2064         * Using attrs_offset plus eight bytes (for the termination attribute).
2065         * attrs_offset is already aligned to 8-byte boundary, so no need to
2066         * align again.
2067         */
2068        m->bytes_in_use = cpu_to_le32(le16_to_cpu(m->attrs_offset) + 8);
2069        m->bytes_allocated = cpu_to_le32(vol->mft_record_size);
2070        m->base_mft_record = 0;
2071        m->next_attr_instance = 0;
2072        /* Add the termination attribute. */
2073        a = (ATTR_RECORD*)((u8*)m + le16_to_cpu(m->attrs_offset));
2074        a->type = AT_END;
2075        a->length = 0;
2076        ntfs_debug("Done.");
2077        return 0;
2078}
2079
2080/**
2081 * ntfs_mft_record_format - format an mft record on an ntfs volume
2082 * @vol:        volume on which to format the mft record
2083 * @mft_no:     mft record number to format
2084 *
2085 * Format the mft record @mft_no in $MFT/$DATA, i.e. lay out an empty, unused
2086 * mft record into the appropriate place of the mft data attribute.  This is
2087 * used when extending the mft data attribute.
2088 *
2089 * Return 0 on success and -errno on error.
2090 */
2091static int ntfs_mft_record_format(const ntfs_volume *vol, const s64 mft_no)
2092{
2093        loff_t i_size;
2094        struct inode *mft_vi = vol->mft_ino;
2095        struct page *page;
2096        MFT_RECORD *m;
2097        pgoff_t index, end_index;
2098        unsigned int ofs;
2099        int err;
2100
2101        ntfs_debug("Entering for mft record 0x%llx.", (long long)mft_no);
2102        /*
2103         * The index into the page cache and the offset within the page cache
2104         * page of the wanted mft record.
2105         */
2106        index = mft_no << vol->mft_record_size_bits >> PAGE_CACHE_SHIFT;
2107        ofs = (mft_no << vol->mft_record_size_bits) & ~PAGE_CACHE_MASK;
2108        /* The maximum valid index into the page cache for $MFT's data. */
2109        i_size = i_size_read(mft_vi);
2110        end_index = i_size >> PAGE_CACHE_SHIFT;
2111        if (unlikely(index >= end_index)) {
2112                if (unlikely(index > end_index || ofs + vol->mft_record_size >=
2113                                (i_size & ~PAGE_CACHE_MASK))) {
2114                        ntfs_error(vol->sb, "Tried to format non-existing mft "
2115                                        "record 0x%llx.", (long long)mft_no);
2116                        return -ENOENT;
2117                }
2118        }
2119        /* Read, map, and pin the page containing the mft record. */
2120        page = ntfs_map_page(mft_vi->i_mapping, index);
2121        if (IS_ERR(page)) {
2122                ntfs_error(vol->sb, "Failed to map page containing mft record "
2123                                "to format 0x%llx.", (long long)mft_no);
2124                return PTR_ERR(page);
2125        }
2126        lock_page(page);
2127        BUG_ON(!PageUptodate(page));
2128        ClearPageUptodate(page);
2129        m = (MFT_RECORD*)((u8*)page_address(page) + ofs);
2130        err = ntfs_mft_record_layout(vol, mft_no, m);
2131        if (unlikely(err)) {
2132                ntfs_error(vol->sb, "Failed to layout mft record 0x%llx.",
2133                                (long long)mft_no);
2134                SetPageUptodate(page);
2135                unlock_page(page);
2136                ntfs_unmap_page(page);
2137                return err;
2138        }
2139        flush_dcache_page(page);
2140        SetPageUptodate(page);
2141        unlock_page(page);
2142        /*
2143         * Make sure the mft record is written out to disk.  We could use
2144         * ilookup5() to check if an inode is in icache and so on but this is
2145         * unnecessary as ntfs_writepage() will write the dirty record anyway.
2146         */
2147        mark_ntfs_record_dirty(page, ofs);
2148        ntfs_unmap_page(page);
2149        ntfs_debug("Done.");
2150        return 0;
2151}
2152
2153/**
2154 * ntfs_mft_record_alloc - allocate an mft record on an ntfs volume
2155 * @vol:        [IN]  volume on which to allocate the mft record
2156 * @mode:       [IN]  mode if want a file or directory, i.e. base inode or 0
2157 * @base_ni:    [IN]  open base inode if allocating an extent mft record or NULL
2158 * @mrec:       [OUT] on successful return this is the mapped mft record
2159 *
2160 * Allocate an mft record in $MFT/$DATA of an open ntfs volume @vol.
2161 *
2162 * If @base_ni is NULL make the mft record a base mft record, i.e. a file or
2163 * direvctory inode, and allocate it at the default allocator position.  In
2164 * this case @mode is the file mode as given to us by the caller.  We in
2165 * particular use @mode to distinguish whether a file or a directory is being
2166 * created (S_IFDIR(mode) and S_IFREG(mode), respectively).
2167 *
2168 * If @base_ni is not NULL make the allocated mft record an extent record,
2169 * allocate it starting at the mft record after the base mft record and attach
2170 * the allocated and opened ntfs inode to the base inode @base_ni.  In this
2171 * case @mode must be 0 as it is meaningless for extent inodes.
2172 *
2173 * You need to check the return value with IS_ERR().  If false, the function
2174 * was successful and the return value is the now opened ntfs inode of the
2175 * allocated mft record.  *@mrec is then set to the allocated, mapped, pinned,
2176 * and locked mft record.  If IS_ERR() is true, the function failed and the
2177 * error code is obtained from PTR_ERR(return value).  *@mrec is undefined in
2178 * this case.
2179 *
2180 * Allocation strategy:
2181 *
2182 * To find a free mft record, we scan the mft bitmap for a zero bit.  To
2183 * optimize this we start scanning at the place specified by @base_ni or if
2184 * @base_ni is NULL we start where we last stopped and we perform wrap around
2185 * when we reach the end.  Note, we do not try to allocate mft records below
2186 * number 24 because numbers 0 to 15 are the defined system files anyway and 16
2187 * to 24 are special in that they are used for storing extension mft records
2188 * for the $DATA attribute of $MFT.  This is required to avoid the possibility
2189 * of creating a runlist with a circular dependency which once written to disk
2190 * can never be read in again.  Windows will only use records 16 to 24 for
2191 * normal files if the volume is completely out of space.  We never use them
2192 * which means that when the volume is really out of space we cannot create any
2193 * more files while Windows can still create up to 8 small files.  We can start
2194 * doing this at some later time, it does not matter much for now.
2195 *
2196 * When scanning the mft bitmap, we only search up to the last allocated mft
2197 * record.  If there are no free records left in the range 24 to number of
2198 * allocated mft records, then we extend the $MFT/$DATA attribute in order to
2199 * create free mft records.  We extend the allocated size of $MFT/$DATA by 16
2200 * records at a time or one cluster, if cluster size is above 16kiB.  If there
2201 * is not sufficient space to do this, we try to extend by a single mft record
2202 * or one cluster, if cluster size is above the mft record size.
2203 *
2204 * No matter how many mft records we allocate, we initialize only the first
2205 * allocated mft record, incrementing mft data size and initialized size
2206 * accordingly, open an ntfs_inode for it and return it to the caller, unless
2207 * there are less than 24 mft records, in which case we allocate and initialize
2208 * mft records until we reach record 24 which we consider as the first free mft
2209 * record for use by normal files.
2210 *
2211 * If during any stage we overflow the initialized data in the mft bitmap, we
2212 * extend the initialized size (and data size) by 8 bytes, allocating another
2213 * cluster if required.  The bitmap data size has to be at least equal to the
2214 * number of mft records in the mft, but it can be bigger, in which case the
2215 * superflous bits are padded with zeroes.
2216 *
2217 * Thus, when we return successfully (IS_ERR() is false), we will have:
2218 *      - initialized / extended the mft bitmap if necessary,
2219 *      - initialized / extended the mft data if necessary,
2220 *      - set the bit corresponding to the mft record being allocated in the
2221 *        mft bitmap,
2222 *      - opened an ntfs_inode for the allocated mft record, and we will have
2223 *      - returned the ntfs_inode as well as the allocated mapped, pinned, and
2224 *        locked mft record.
2225 *
2226 * On error, the volume will be left in a consistent state and no record will
2227 * be allocated.  If rolling back a partial operation fails, we may leave some
2228 * inconsistent metadata in which case we set NVolErrors() so the volume is
2229 * left dirty when unmounted.
2230 *
2231 * Note, this function cannot make use of most of the normal functions, like
2232 * for example for attribute resizing, etc, because when the run list overflows
2233 * the base mft record and an attribute list is used, it is very important that
2234 * the extension mft records used to store the $DATA attribute of $MFT can be
2235 * reached without having to read the information contained inside them, as
2236 * this would make it impossible to find them in the first place after the
2237 * volume is unmounted.  $MFT/$BITMAP probably does not need to follow this
2238 * rule because the bitmap is not essential for finding the mft records, but on
2239 * the other hand, handling the bitmap in this special way would make life
2240 * easier because otherwise there might be circular invocations of functions
2241 * when reading the bitmap.
2242 */
2243ntfs_inode *ntfs_mft_record_alloc(ntfs_volume *vol, const int mode,
2244                ntfs_inode *base_ni, MFT_RECORD **mrec)
2245{
2246        s64 ll, bit, old_data_initialized, old_data_size;
2247        unsigned long flags;
2248        struct inode *vi;
2249        struct page *page;
2250        ntfs_inode *mft_ni, *mftbmp_ni, *ni;
2251        ntfs_attr_search_ctx *ctx;
2252        MFT_RECORD *m;
2253        ATTR_RECORD *a;
2254        pgoff_t index;
2255        unsigned int ofs;
2256        int err;
2257        le16 seq_no, usn;
2258        bool record_formatted = false;
2259
2260        if (base_ni) {
2261                ntfs_debug("Entering (allocating an extent mft record for "
2262                                "base mft record 0x%llx).",
2263                                (long long)base_ni->mft_no);
2264                /* @mode and @base_ni are mutually exclusive. */
2265                BUG_ON(mode);
2266        } else
2267                ntfs_debug("Entering (allocating a base mft record).");
2268        if (mode) {
2269                /* @mode and @base_ni are mutually exclusive. */
2270                BUG_ON(base_ni);
2271                /* We only support creation of normal files and directories. */
2272                if (!S_ISREG(mode) && !S_ISDIR(mode))
2273                        return ERR_PTR(-EOPNOTSUPP);
2274        }
2275        BUG_ON(!mrec);
2276        mft_ni = NTFS_I(vol->mft_ino);
2277        mftbmp_ni = NTFS_I(vol->mftbmp_ino);
2278        down_write(&vol->mftbmp_lock);
2279        bit = ntfs_mft_bitmap_find_and_alloc_free_rec_nolock(vol, base_ni);
2280        if (bit >= 0) {
2281                ntfs_debug("Found and allocated free record (#1), bit 0x%llx.",
2282                                (long long)bit);
2283                goto have_alloc_rec;
2284        }
2285        if (bit != -ENOSPC) {
2286                up_write(&vol->mftbmp_lock);
2287                return ERR_PTR(bit);
2288        }
2289        /*
2290         * No free mft records left.  If the mft bitmap already covers more
2291         * than the currently used mft records, the next records are all free,
2292         * so we can simply allocate the first unused mft record.
2293         * Note: We also have to make sure that the mft bitmap at least covers
2294         * the first 24 mft records as they are special and whilst they may not
2295         * be in use, we do not allocate from them.
2296         */
2297        read_lock_irqsave(&mft_ni->size_lock, flags);
2298        ll = mft_ni->initialized_size >> vol->mft_record_size_bits;
2299        read_unlock_irqrestore(&mft_ni->size_lock, flags);
2300        read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2301        old_data_initialized = mftbmp_ni->initialized_size;
2302        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2303        if (old_data_initialized << 3 > ll && old_data_initialized > 3) {
2304                bit = ll;
2305                if (bit < 24)
2306                        bit = 24;
2307                if (unlikely(bit >= (1ll << 32)))
2308                        goto max_err_out;
2309                ntfs_debug("Found free record (#2), bit 0x%llx.",
2310                                (long long)bit);
2311                goto found_free_rec;
2312        }
2313        /*
2314         * The mft bitmap needs to be expanded until it covers the first unused
2315         * mft record that we can allocate.
2316         * Note: The smallest mft record we allocate is mft record 24.
2317         */
2318        bit = old_data_initialized << 3;
2319        if (unlikely(bit >= (1ll << 32)))
2320                goto max_err_out;
2321        read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2322        old_data_size = mftbmp_ni->allocated_size;
2323        ntfs_debug("Status of mftbmp before extension: allocated_size 0x%llx, "
2324                        "data_size 0x%llx, initialized_size 0x%llx.",
2325                        (long long)old_data_size,
2326                        (long long)i_size_read(vol->mftbmp_ino),
2327                        (long long)old_data_initialized);
2328        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2329        if (old_data_initialized + 8 > old_data_size) {
2330                /* Need to extend bitmap by one more cluster. */
2331                ntfs_debug("mftbmp: initialized_size + 8 > allocated_size.");
2332                err = ntfs_mft_bitmap_extend_allocation_nolock(vol);
2333                if (unlikely(err)) {
2334                        up_write(&vol->mftbmp_lock);
2335                        goto err_out;
2336                }
2337#ifdef DEBUG
2338                read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2339                ntfs_debug("Status of mftbmp after allocation extension: "
2340                                "allocated_size 0x%llx, data_size 0x%llx, "
2341                                "initialized_size 0x%llx.",
2342                                (long long)mftbmp_ni->allocated_size,
2343                                (long long)i_size_read(vol->mftbmp_ino),
2344                                (long long)mftbmp_ni->initialized_size);
2345                read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2346#endif /* DEBUG */
2347        }
2348        /*
2349         * We now have sufficient allocated space, extend the initialized_size
2350         * as well as the data_size if necessary and fill the new space with
2351         * zeroes.
2352         */
2353        err = ntfs_mft_bitmap_extend_initialized_nolock(vol);
2354        if (unlikely(err)) {
2355                up_write(&vol->mftbmp_lock);
2356                goto err_out;
2357        }
2358#ifdef DEBUG
2359        read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2360        ntfs_debug("Status of mftbmp after initialized extension: "
2361                        "allocated_size 0x%llx, data_size 0x%llx, "
2362                        "initialized_size 0x%llx.",
2363                        (long long)mftbmp_ni->allocated_size,
2364                        (long long)i_size_read(vol->mftbmp_ino),
2365                        (long long)mftbmp_ni->initialized_size);
2366        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2367#endif /* DEBUG */
2368        ntfs_debug("Found free record (#3), bit 0x%llx.", (long long)bit);
2369found_free_rec:
2370        /* @bit is the found free mft record, allocate it in the mft bitmap. */
2371        ntfs_debug("At found_free_rec.");
2372        err = ntfs_bitmap_set_bit(vol->mftbmp_ino, bit);
2373        if (unlikely(err)) {
2374                ntfs_error(vol->sb, "Failed to allocate bit in mft bitmap.");
2375                up_write(&vol->mftbmp_lock);
2376                goto err_out;
2377        }
2378        ntfs_debug("Set bit 0x%llx in mft bitmap.", (long long)bit);
2379have_alloc_rec:
2380        /*
2381         * The mft bitmap is now uptodate.  Deal with mft data attribute now.
2382         * Note, we keep hold of the mft bitmap lock for writing until all
2383         * modifications to the mft data attribute are complete, too, as they
2384         * will impact decisions for mft bitmap and mft record allocation done
2385         * by a parallel allocation and if the lock is not maintained a
2386         * parallel allocation could allocate the same mft record as this one.
2387         */
2388        ll = (bit + 1) << vol->mft_record_size_bits;
2389        read_lock_irqsave(&mft_ni->size_lock, flags);
2390        old_data_initialized = mft_ni->initialized_size;
2391        read_unlock_irqrestore(&mft_ni->size_lock, flags);
2392        if (ll <= old_data_initialized) {
2393                ntfs_debug("Allocated mft record already initialized.");
2394                goto mft_rec_already_initialized;
2395        }
2396        ntfs_debug("Initializing allocated mft record.");
2397        /*
2398         * The mft record is outside the initialized data.  Extend the mft data
2399         * attribute until it covers the allocated record.  The loop is only
2400         * actually traversed more than once when a freshly formatted volume is
2401         * first written to so it optimizes away nicely in the common case.
2402         */
2403        read_lock_irqsave(&mft_ni->size_lock, flags);
2404        ntfs_debug("Status of mft data before extension: "
2405                        "allocated_size 0x%llx, data_size 0x%llx, "
2406                        "initialized_size 0x%llx.",
2407                        (long long)mft_ni->allocated_size,
2408                        (long long)i_size_read(vol->mft_ino),
2409                        (long long)mft_ni->initialized_size);
2410        while (ll > mft_ni->allocated_size) {
2411                read_unlock_irqrestore(&mft_ni->size_lock, flags);
2412                err = ntfs_mft_data_extend_allocation_nolock(vol);
2413                if (unlikely(err)) {
2414                        ntfs_error(vol->sb, "Failed to extend mft data "
2415                                        "allocation.");
2416                        goto undo_mftbmp_alloc_nolock;
2417                }
2418                read_lock_irqsave(&mft_ni->size_lock, flags);
2419                ntfs_debug("Status of mft data after allocation extension: "
2420                                "allocated_size 0x%llx, data_size 0x%llx, "
2421                                "initialized_size 0x%llx.",
2422                                (long long)mft_ni->allocated_size,
2423                                (long long)i_size_read(vol->mft_ino),
2424                                (long long)mft_ni->initialized_size);
2425        }
2426        read_unlock_irqrestore(&mft_ni->size_lock, flags);
2427        /*
2428         * Extend mft data initialized size (and data size of course) to reach
2429         * the allocated mft record, formatting the mft records allong the way.
2430         * Note: We only modify the ntfs_inode structure as that is all that is
2431         * needed by ntfs_mft_record_format().  We will update the attribute
2432         * record itself in one fell swoop later on.
2433         */
2434        write_lock_irqsave(&mft_ni->size_lock, flags);
2435        old_data_initialized = mft_ni->initialized_size;
2436        old_data_size = vol->mft_ino->i_size;
2437        while (ll > mft_ni->initialized_size) {
2438                s64 new_initialized_size, mft_no;
2439                
2440                new_initialized_size = mft_ni->initialized_size +
2441                                vol->mft_record_size;
2442                mft_no = mft_ni->initialized_size >> vol->mft_record_size_bits;
2443                if (new_initialized_size > i_size_read(vol->mft_ino))
2444                        i_size_write(vol->mft_ino, new_initialized_size);
2445                write_unlock_irqrestore(&mft_ni->size_lock, flags);
2446                ntfs_debug("Initializing mft record 0x%llx.",
2447                                (long long)mft_no);
2448                err = ntfs_mft_record_format(vol, mft_no);
2449                if (unlikely(err)) {
2450                        ntfs_error(vol->sb, "Failed to format mft record.");
2451                        goto undo_data_init;
2452                }
2453                write_lock_irqsave(&mft_ni->size_lock, flags);
2454                mft_ni->initialized_size = new_initialized_size;
2455        }
2456        write_unlock_irqrestore(&mft_ni->size_lock, flags);
2457        record_formatted = true;
2458        /* Update the mft data attribute record to reflect the new sizes. */
2459        m = map_mft_record(mft_ni);
2460        if (IS_ERR(m)) {
2461                ntfs_error(vol->sb, "Failed to map mft record.");
2462                err = PTR_ERR(m);
2463                goto undo_data_init;
2464        }
2465        ctx = ntfs_attr_get_search_ctx(mft_ni, m);
2466        if (unlikely(!ctx)) {
2467                ntfs_error(vol->sb, "Failed to get search context.");
2468                err = -ENOMEM;
2469                unmap_mft_record(mft_ni);
2470                goto undo_data_init;
2471        }
2472        err = ntfs_attr_lookup(mft_ni->type, mft_ni->name, mft_ni->name_len,
2473                        CASE_SENSITIVE, 0, NULL, 0, ctx);
2474        if (unlikely(err)) {
2475                ntfs_error(vol->sb, "Failed to find first attribute extent of "
2476                                "mft data attribute.");
2477                ntfs_attr_put_search_ctx(ctx);
2478                unmap_mft_record(mft_ni);
2479                goto undo_data_init;
2480        }
2481        a = ctx->attr;
2482        read_lock_irqsave(&mft_ni->size_lock, flags);
2483        a->data.non_resident.initialized_size =
2484                        cpu_to_sle64(mft_ni->initialized_size);
2485        a->data.non_resident.data_size =
2486                        cpu_to_sle64(i_size_read(vol->mft_ino));
2487        read_unlock_irqrestore(&mft_ni->size_lock, flags);
2488        /* Ensure the changes make it to disk. */
2489        flush_dcache_mft_record_page(ctx->ntfs_ino);
2490        mark_mft_record_dirty(ctx->ntfs_ino);
2491        ntfs_attr_put_search_ctx(ctx);
2492        unmap_mft_record(mft_ni);
2493        read_lock_irqsave(&mft_ni->size_lock, flags);
2494        ntfs_debug("Status of mft data after mft record initialization: "
2495                        "allocated_size 0x%llx, data_size 0x%llx, "
2496                        "initialized_size 0x%llx.",
2497                        (long long)mft_ni->allocated_size,
2498                        (long long)i_size_read(vol->mft_ino),
2499                        (long long)mft_ni->initialized_size);
2500        BUG_ON(i_size_read(vol->mft_ino) > mft_ni->allocated_size);
2501        BUG_ON(mft_ni->initialized_size > i_size_read(vol->mft_ino));
2502        read_unlock_irqrestore(&mft_ni->size_lock, flags);
2503mft_rec_already_initialized:
2504        /*
2505         * We can finally drop the mft bitmap lock as the mft data attribute
2506         * has been fully updated.  The only disparity left is that the
2507         * allocated mft record still needs to be marked as in use to match the
2508         * set bit in the mft bitmap but this is actually not a problem since
2509         * this mft record is not referenced from anywhere yet and the fact
2510         * that it is allocated in the mft bitmap means that no-one will try to
2511         * allocate it either.
2512         */
2513        up_write(&vol->mftbmp_lock);
2514        /*
2515         * We now have allocated and initialized the mft record.  Calculate the
2516         * index of and the offset within the page cache page the record is in.
2517         */
2518        index = bit << vol->mft_record_size_bits >> PAGE_CACHE_SHIFT;
2519        ofs = (bit << vol->mft_record_size_bits) & ~PAGE_CACHE_MASK;
2520        /* Read, map, and pin the page containing the mft record. */
2521        page = ntfs_map_page(vol->mft_ino->i_mapping, index);
2522        if (IS_ERR(page)) {
2523                ntfs_error(vol->sb, "Failed to map page containing allocated "
2524                                "mft record 0x%llx.", (long long)bit);
2525                err = PTR_ERR(page);
2526                goto undo_mftbmp_alloc;
2527        }
2528        lock_page(page);
2529        BUG_ON(!PageUptodate(page));
2530        ClearPageUptodate(page);
2531        m = (MFT_RECORD*)((u8*)page_address(page) + ofs);
2532        /* If we just formatted the mft record no need to do it again. */
2533        if (!record_formatted) {
2534                /* Sanity check that the mft record is really not in use. */
2535                if (ntfs_is_file_record(m->magic) &&
2536                                (m->flags & MFT_RECORD_IN_USE)) {
2537                        ntfs_error(vol->sb, "Mft record 0x%llx was marked "
2538                                        "free in mft bitmap but is marked "
2539                                        "used itself.  Corrupt filesystem.  "
2540                                        "Unmount and run chkdsk.",
2541                                        (long long)bit);
2542                        err = -EIO;
2543                        SetPageUptodate(page);
2544                        unlock_page(page);
2545                        ntfs_unmap_page(page);
2546                        NVolSetErrors(vol);
2547                        goto undo_mftbmp_alloc;
2548                }
2549                /*
2550                 * We need to (re-)format the mft record, preserving the
2551                 * sequence number if it is not zero as well as the update
2552                 * sequence number if it is not zero or -1 (0xffff).  This
2553                 * means we do not need to care whether or not something went
2554                 * wrong with the previous mft record.
2555                 */
2556                seq_no = m->sequence_number;
2557                usn = *(le16*)((u8*)m + le16_to_cpu(m->usa_ofs));
2558                err = ntfs_mft_record_layout(vol, bit, m);
2559                if (unlikely(err)) {
2560                        ntfs_error(vol->sb, "Failed to layout allocated mft "
2561                                        "record 0x%llx.", (long long)bit);
2562                        SetPageUptodate(page);
2563                        unlock_page(page);
2564                        ntfs_unmap_page(page);
2565                        goto undo_mftbmp_alloc;
2566                }
2567                if (seq_no)
2568                        m->sequence_number = seq_no;
2569                if (usn && le16_to_cpu(usn) != 0xffff)
2570                        *(le16*)((u8*)m + le16_to_cpu(m->usa_ofs)) = usn;
2571        }
2572        /* Set the mft record itself in use. */
2573        m->flags |= MFT_RECORD_IN_USE;
2574        if (S_ISDIR(mode))
2575                m->flags |= MFT_RECORD_IS_DIRECTORY;
2576        flush_dcache_page(page);
2577        SetPageUptodate(page);
2578        if (base_ni) {
2579                MFT_RECORD *m_tmp;
2580
2581                /*
2582                 * Setup the base mft record in the extent mft record.  This
2583                 * completes initialization of the allocated extent mft record
2584                 * and we can simply use it with map_extent_mft_record().
2585                 */
2586                m->base_mft_record = MK_LE_MREF(base_ni->mft_no,
2587                                base_ni->seq_no);
2588                /*
2589                 * Allocate an extent inode structure for the new mft record,
2590                 * attach it to the base inode @base_ni and map, pin, and lock
2591                 * its, i.e. the allocated, mft record.
2592                 */
2593                m_tmp = map_extent_mft_record(base_ni, bit, &ni);
2594                if (IS_ERR(m_tmp)) {
2595                        ntfs_error(vol->sb, "Failed to map allocated extent "
2596                                        "mft record 0x%llx.", (long long)bit);
2597                        err = PTR_ERR(m_tmp);
2598                        /* Set the mft record itself not in use. */
2599                        m->flags &= cpu_to_le16(
2600                                        ~le16_to_cpu(MFT_RECORD_IN_USE));
2601                        flush_dcache_page(page);
2602                        /* Make sure the mft record is written out to disk. */
2603                        mark_ntfs_record_dirty(page, ofs);
2604                        unlock_page(page);
2605                        ntfs_unmap_page(page);
2606                        goto undo_mftbmp_alloc;
2607                }
2608                BUG_ON(m != m_tmp);
2609                /*
2610                 * Make sure the allocated mft record is written out to disk.
2611                 * No need to set the inode dirty because the caller is going
2612                 * to do that anyway after finishing with the new extent mft
2613                 * record (e.g. at a minimum a new attribute will be added to
2614                 * the mft record.
2615                 */
2616                mark_ntfs_record_dirty(page, ofs);
2617                unlock_page(page);
2618                /*
2619                 * Need to unmap the page since map_extent_mft_record() mapped
2620                 * it as well so we have it mapped twice at the moment.
2621                 */
2622                ntfs_unmap_page(page);
2623        } else {
2624                /*
2625                 * Allocate a new VFS inode and set it up.  NOTE: @vi->i_nlink
2626                 * is set to 1 but the mft record->link_count is 0.  The caller
2627                 * needs to bear this in mind.
2628                 */
2629                vi = new_inode(vol->sb);
2630                if (unlikely(!vi)) {
2631                        err = -ENOMEM;
2632                        /* Set the mft record itself not in use. */
2633                        m->flags &= cpu_to_le16(
2634                                        ~le16_to_cpu(MFT_RECORD_IN_USE));
2635                        flush_dcache_page(page);
2636                        /* Make sure the mft record is written out to disk. */
2637                        mark_ntfs_record_dirty(page, ofs);
2638                        unlock_page(page);
2639                        ntfs_unmap_page(page);
2640                        goto undo_mftbmp_alloc;
2641                }
2642                vi->i_ino = bit;
2643                /*
2644                 * This is for checking whether an inode has changed w.r.t. a
2645                 * file so that the file can be updated if necessary (compare
2646                 * with f_version).
2647                 */
2648                vi->i_version = 1;
2649
2650                /* The owner and group come from the ntfs volume. */
2651                vi->i_uid = vol->uid;
2652                vi->i_gid = vol->gid;
2653
2654                /* Initialize the ntfs specific part of @vi. */
2655                ntfs_init_big_inode(vi);
2656                ni = NTFS_I(vi);
2657                /*
2658                 * Set the appropriate mode, attribute type, and name.  For
2659                 * directories, also setup the index values to the defaults.
2660                 */
2661                if (S_ISDIR(mode)) {
2662                        vi->i_mode = S_IFDIR | S_IRWXUGO;
2663                        vi->i_mode &= ~vol->dmask;
2664
2665                        NInoSetMstProtected(ni);
2666                        ni->type = AT_INDEX_ALLOCATION;
2667                        ni->name = I30;
2668                        ni->name_len = 4;
2669
2670                        ni->itype.index.block_size = 4096;
2671                        ni->itype.index.block_size_bits = ntfs_ffs(4096) - 1;
2672                        ni->itype.index.collation_rule = COLLATION_FILE_NAME;
2673                        if (vol->cluster_size <= ni->itype.index.block_size) {
2674                                ni->itype.index.vcn_size = vol->cluster_size;
2675                                ni->itype.index.vcn_size_bits =
2676                                                vol->cluster_size_bits;
2677                        } else {
2678                                ni->itype.index.vcn_size = vol->sector_size;
2679                                ni->itype.index.vcn_size_bits =
2680                                                vol->sector_size_bits;
2681                        }
2682                } else {
2683                        vi->i_mode = S_IFREG | S_IRWXUGO;
2684                        vi->i_mode &= ~vol->fmask;
2685
2686                        ni->type = AT_DATA;
2687                        ni->name = NULL;
2688                        ni->name_len = 0;
2689                }
2690                if (IS_RDONLY(vi))
2691                        vi->i_mode &= ~S_IWUGO;
2692
2693                /* Set the inode times to the current time. */
2694                vi->i_atime = vi->i_mtime = vi->i_ctime =
2695                        current_fs_time(vi->i_sb);
2696                /*
2697                 * Set the file size to 0, the ntfs inode sizes are set to 0 by
2698                 * the call to ntfs_init_big_inode() below.
2699                 */
2700                vi->i_size = 0;
2701                vi->i_blocks = 0;
2702
2703                /* Set the sequence number. */
2704                vi->i_generation = ni->seq_no = le16_to_cpu(m->sequence_number);
2705                /*
2706                 * Manually map, pin, and lock the mft record as we already
2707                 * have its page mapped and it is very easy to do.
2708                 */
2709                atomic_inc(&ni->count);
2710                mutex_lock(&ni->mrec_lock);
2711                ni->page = page;
2712                ni->page_ofs = ofs;
2713                /*
2714                 * Make sure the allocated mft record is written out to disk.
2715                 * NOTE: We do not set the ntfs inode dirty because this would
2716                 * fail in ntfs_write_inode() because the inode does not have a
2717                 * standard information attribute yet.  Also, there is no need
2718                 * to set the inode dirty because the caller is going to do
2719                 * that anyway after finishing with the new mft record (e.g. at
2720                 * a minimum some new attributes will be added to the mft
2721                 * record.
2722                 */
2723                mark_ntfs_record_dirty(page, ofs);
2724                unlock_page(page);
2725
2726                /* Add the inode to the inode hash for the superblock. */
2727                insert_inode_hash(vi);
2728
2729                /* Update the default mft allocation position. */
2730                vol->mft_data_pos = bit + 1;
2731        }
2732        /*
2733         * Return the opened, allocated inode of the allocated mft record as
2734         * well as the mapped, pinned, and locked mft record.
2735         */
2736        ntfs_debug("Returning opened, allocated %sinode 0x%llx.",
2737                        base_ni ? "extent " : "", (long long)bit);
2738        *mrec = m;
2739        return ni;
2740undo_data_init:
2741        write_lock_irqsave(&mft_ni->size_lock, flags);
2742        mft_ni->initialized_size = old_data_initialized;
2743        i_size_write(vol->mft_ino, old_data_size);
2744        write_unlock_irqrestore(&mft_ni->size_lock, flags);
2745        goto undo_mftbmp_alloc_nolock;
2746undo_mftbmp_alloc:
2747        down_write(&vol->mftbmp_lock);
2748undo_mftbmp_alloc_nolock:
2749        if (ntfs_bitmap_clear_bit(vol->mftbmp_ino, bit)) {
2750                ntfs_error(vol->sb, "Failed to clear bit in mft bitmap.%s", es);
2751                NVolSetErrors(vol);
2752        }
2753        up_write(&vol->mftbmp_lock);
2754err_out:
2755        return ERR_PTR(err);
2756max_err_out:
2757        ntfs_warning(vol->sb, "Cannot allocate mft record because the maximum "
2758                        "number of inodes (2^32) has already been reached.");
2759        up_write(&vol->mftbmp_lock);
2760        return ERR_PTR(-ENOSPC);
2761}
2762
2763/**
2764 * ntfs_extent_mft_record_free - free an extent mft record on an ntfs volume
2765 * @ni:         ntfs inode of the mapped extent mft record to free
2766 * @m:          mapped extent mft record of the ntfs inode @ni
2767 *
2768 * Free the mapped extent mft record @m of the extent ntfs inode @ni.
2769 *
2770 * Note that this function unmaps the mft record and closes and destroys @ni
2771 * internally and hence you cannot use either @ni nor @m any more after this
2772 * function returns success.
2773 *
2774 * On success return 0 and on error return -errno.  @ni and @m are still valid
2775 * in this case and have not been freed.
2776 *
2777 * For some errors an error message is displayed and the success code 0 is
2778 * returned and the volume is then left dirty on umount.  This makes sense in
2779 * case we could not rollback the changes that were already done since the
2780 * caller no longer wants to reference this mft record so it does not matter to
2781 * the caller if something is wrong with it as long as it is properly detached
2782 * from the base inode.
2783 */
2784int ntfs_extent_mft_record_free(ntfs_inode *ni, MFT_RECORD *m)
2785{
2786        unsigned long mft_no = ni->mft_no;
2787        ntfs_volume *vol = ni->vol;
2788        ntfs_inode *base_ni;
2789        ntfs_inode **extent_nis;
2790        int i, err;
2791        le16 old_seq_no;
2792        u16 seq_no;
2793        
2794        BUG_ON(NInoAttr(ni));
2795        BUG_ON(ni->nr_extents != -1);
2796
2797        mutex_lock(&ni->extent_lock);
2798        base_ni = ni->ext.base_ntfs_ino;
2799        mutex_unlock(&ni->extent_lock);
2800
2801        BUG_ON(base_ni->nr_extents <= 0);
2802
2803        ntfs_debug("Entering for extent inode 0x%lx, base inode 0x%lx.\n",
2804                        mft_no, base_ni->mft_no);
2805
2806        mutex_lock(&base_ni->extent_lock);
2807
2808        /* Make sure we are holding the only reference to the extent inode. */
2809        if (atomic_read(&ni->count) > 2) {
2810                ntfs_error(vol->sb, "Tried to free busy extent inode 0x%lx, "
2811                                "not freeing.", base_ni->mft_no);
2812                mutex_unlock(&base_ni->extent_lock);
2813                return -EBUSY;
2814        }
2815
2816        /* Dissociate the ntfs inode from the base inode. */
2817        extent_nis = base_ni->ext.extent_ntfs_inos;
2818        err = -ENOENT;
2819        for (i = 0; i < base_ni->nr_extents; i++) {
2820                if (ni != extent_nis[i])
2821                        continue;
2822                extent_nis += i;
2823                base_ni->nr_extents--;
2824                memmove(extent_nis, extent_nis + 1, (base_ni->nr_extents - i) *
2825                                sizeof(ntfs_inode*));
2826                err = 0;
2827                break;
2828        }
2829
2830        mutex_unlock(&base_ni->extent_lock);
2831
2832        if (unlikely(err)) {
2833                ntfs_error(vol->sb, "Extent inode 0x%lx is not attached to "
2834                                "its base inode 0x%lx.", mft_no,
2835                                base_ni->mft_no);
2836                BUG();
2837        }
2838
2839        /*
2840         * The extent inode is no longer attached to the base inode so no one
2841         * can get a reference to it any more.
2842         */
2843
2844        /* Mark the mft record as not in use. */
2845        m->flags &= ~MFT_RECORD_IN_USE;
2846
2847        /* Increment the sequence number, skipping zero, if it is not zero. */
2848        old_seq_no = m->sequence_number;
2849        seq_no = le16_to_cpu(old_seq_no);
2850        if (seq_no == 0xffff)
2851                seq_no = 1;
2852        else if (seq_no)
2853                seq_no++;
2854        m->sequence_number = cpu_to_le16(seq_no);
2855
2856        /*
2857         * Set the ntfs inode dirty and write it out.  We do not need to worry
2858         * about the base inode here since whatever caused the extent mft
2859         * record to be freed is guaranteed to do it already.
2860         */
2861        NInoSetDirty(ni);
2862        err = write_mft_record(ni, m, 0);
2863        if (unlikely(err)) {
2864                ntfs_error(vol->sb, "Failed to write mft record 0x%lx, not "
2865                                "freeing.", mft_no);
2866                goto rollback;
2867        }
2868rollback_error:
2869        /* Unmap and throw away the now freed extent inode. */
2870        unmap_extent_mft_record(ni);
2871        ntfs_clear_extent_inode(ni);
2872
2873        /* Clear the bit in the $MFT/$BITMAP corresponding to this record. */
2874        down_write(&vol->mftbmp_lock);
2875        err = ntfs_bitmap_clear_bit(vol->mftbmp_ino, mft_no);
2876        up_write(&vol->mftbmp_lock);
2877        if (unlikely(err)) {
2878                /*
2879                 * The extent inode is gone but we failed to deallocate it in
2880                 * the mft bitmap.  Just emit a warning and leave the volume
2881                 * dirty on umount.
2882                 */
2883                ntfs_error(vol->sb, "Failed to clear bit in mft bitmap.%s", es);
2884                NVolSetErrors(vol);
2885        }
2886        return 0;
2887rollback:
2888        /* Rollback what we did... */
2889        mutex_lock(&base_ni->extent_lock);
2890        extent_nis = base_ni->ext.extent_ntfs_inos;
2891        if (!(base_ni->nr_extents & 3)) {
2892                int new_size = (base_ni->nr_extents + 4) * sizeof(ntfs_inode*);
2893
2894                extent_nis = kmalloc(new_size, GFP_NOFS);
2895                if (unlikely(!extent_nis)) {
2896                        ntfs_error(vol->sb, "Failed to allocate internal "
2897                                        "buffer during rollback.%s", es);
2898                        mutex_unlock(&base_ni->extent_lock);
2899                        NVolSetErrors(vol);
2900                        goto rollback_error;
2901                }
2902                if (base_ni->nr_extents) {
2903                        BUG_ON(!base_ni->ext.extent_ntfs_inos);
2904                        memcpy(extent_nis, base_ni->ext.extent_ntfs_inos,
2905                                        new_size - 4 * sizeof(ntfs_inode*));
2906                        kfree(base_ni->ext.extent_ntfs_inos);
2907                }
2908                base_ni->ext.extent_ntfs_inos = extent_nis;
2909        }
2910        m->flags |= MFT_RECORD_IN_USE;
2911        m->sequence_number = old_seq_no;
2912        extent_nis[base_ni->nr_extents++] = ni;
2913        mutex_unlock(&base_ni->extent_lock);
2914        mark_mft_record_dirty(ni);
2915        return err;
2916}
2917#endif /* NTFS_RW */
2918
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