The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/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  */
   47 static 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         }
   99 err_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  */
  155 MFT_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  */
  191 static 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  */
  213 void 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  */
  246 MFT_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                 }
  298 map_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;
  357 unm_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  */
  395 void __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 
  412 static 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 $MFTMirr inode itself.
  425  *
  426  * This function is only for use at umount time when the mft mirror inode has
  427  * already been disposed off.  We BUG() if we are called while the mft mirror
  428  * inode is still attached to the volume.
  429  *
  430  * On success return 0.  On error return -errno.
  431  *
  432  * NOTE:  This function is not implemented yet as I am not convinced it can
  433  * actually be triggered considering the sequence of commits we do in super.c::
  434  * ntfs_put_super().  But just in case we provide this place holder as the
  435  * alternative would be either to BUG() or to get a NULL pointer dereference
  436  * and Oops.
  437  */
  438 static int ntfs_sync_mft_mirror_umount(ntfs_volume *vol,
  439                 const unsigned long mft_no, MFT_RECORD *m)
  440 {
  441         BUG_ON(vol->mftmirr_ino);
  442         ntfs_error(vol->sb, "Umount time mft mirror syncing is not "
  443                         "implemented yet.  %s", ntfs_please_email);
  444         return -EOPNOTSUPP;
  445 }
  446 
  447 /**
  448  * ntfs_sync_mft_mirror - synchronize an mft record to the mft mirror
  449  * @vol:        ntfs volume on which the mft record to synchronize resides
  450  * @mft_no:     mft record number of mft record to synchronize
  451  * @m:          mapped, mst protected (extent) mft record to synchronize
  452  * @sync:       if true, wait for i/o completion
  453  *
  454  * Write the mapped, mst protected (extent) mft record @m with mft record
  455  * number @mft_no to the mft mirror ($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  */
  465 int 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);
  628 err_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  */
  669 int 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         }
  822 done:
  823         ntfs_debug("Done.");
  824         return 0;
  825 cleanup_out:
  826         /* Clean the buffers. */
  827         for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++)
  828                 clear_buffer_dirty(bhs[i_bhs]);
  829 err_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  */
  925 bool 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 
 1109 static 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  */
 1131 static 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  */
 1278 static 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;
 1497 restore_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);
 1519 undo_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  */
 1577 static 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);
 1662 put_err_out:
 1663                 ntfs_attr_put_search_ctx(ctx);
 1664 unm_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 */
 1691 err_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  */
 1714 static 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;
 1936 restore_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);
 1957 undo_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  */
 2012 static 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  */
 2091 static 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  */
 2243 ntfs_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);
 2369 found_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);
 2379 have_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);
 2503 mft_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;
 2740 undo_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;
 2746 undo_mftbmp_alloc:
 2747         down_write(&vol->mftbmp_lock);
 2748 undo_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);
 2754 err_out:
 2755         return ERR_PTR(err);
 2756 max_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  */
 2784 int 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         }
 2868 rollback_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;
 2887 rollback:
 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 */

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