~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/ntfs/mft.c

Version: ~ [ linux-5.2-rc4 ] ~ [ linux-5.1.9 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.50 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.125 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.181 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.181 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.68 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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 #include <linux/bio.h>
 27 
 28 #include "attrib.h"
 29 #include "aops.h"
 30 #include "bitmap.h"
 31 #include "debug.h"
 32 #include "dir.h"
 33 #include "lcnalloc.h"
 34 #include "malloc.h"
 35 #include "mft.h"
 36 #include "ntfs.h"
 37 
 38 /**
 39  * map_mft_record_page - map the page in which a specific mft record resides
 40  * @ni:         ntfs inode whose mft record page to map
 41  *
 42  * This maps the page in which the mft record of the ntfs inode @ni is situated
 43  * and returns a pointer to the mft record within the mapped page.
 44  *
 45  * Return value needs to be checked with IS_ERR() and if that is true PTR_ERR()
 46  * contains the negative error code returned.
 47  */
 48 static inline MFT_RECORD *map_mft_record_page(ntfs_inode *ni)
 49 {
 50         loff_t i_size;
 51         ntfs_volume *vol = ni->vol;
 52         struct inode *mft_vi = vol->mft_ino;
 53         struct page *page;
 54         unsigned long index, end_index;
 55         unsigned ofs;
 56 
 57         BUG_ON(ni->page);
 58         /*
 59          * The index into the page cache and the offset within the page cache
 60          * page of the wanted mft record. FIXME: We need to check for
 61          * overflowing the unsigned long, but I don't think we would ever get
 62          * here if the volume was that big...
 63          */
 64         index = (u64)ni->mft_no << vol->mft_record_size_bits >>
 65                         PAGE_SHIFT;
 66         ofs = (ni->mft_no << vol->mft_record_size_bits) & ~PAGE_MASK;
 67 
 68         i_size = i_size_read(mft_vi);
 69         /* The maximum valid index into the page cache for $MFT's data. */
 70         end_index = i_size >> PAGE_SHIFT;
 71 
 72         /* If the wanted index is out of bounds the mft record doesn't exist. */
 73         if (unlikely(index >= end_index)) {
 74                 if (index > end_index || (i_size & ~PAGE_MASK) < ofs +
 75                                 vol->mft_record_size) {
 76                         page = ERR_PTR(-ENOENT);
 77                         ntfs_error(vol->sb, "Attempt to read mft record 0x%lx, "
 78                                         "which is beyond the end of the mft.  "
 79                                         "This is probably a bug in the ntfs "
 80                                         "driver.", ni->mft_no);
 81                         goto err_out;
 82                 }
 83         }
 84         /* Read, map, and pin the page. */
 85         page = ntfs_map_page(mft_vi->i_mapping, index);
 86         if (likely(!IS_ERR(page))) {
 87                 /* Catch multi sector transfer fixup errors. */
 88                 if (likely(ntfs_is_mft_recordp((le32*)(page_address(page) +
 89                                 ofs)))) {
 90                         ni->page = page;
 91                         ni->page_ofs = ofs;
 92                         return page_address(page) + ofs;
 93                 }
 94                 ntfs_error(vol->sb, "Mft record 0x%lx is corrupt.  "
 95                                 "Run chkdsk.", ni->mft_no);
 96                 ntfs_unmap_page(page);
 97                 page = ERR_PTR(-EIO);
 98                 NVolSetErrors(vol);
 99         }
100 err_out:
101         ni->page = NULL;
102         ni->page_ofs = 0;
103         return (void*)page;
104 }
105 
106 /**
107  * map_mft_record - map, pin and lock an mft record
108  * @ni:         ntfs inode whose MFT record to map
109  *
110  * First, take the mrec_lock mutex.  We might now be sleeping, while waiting
111  * for the mutex if it was already locked by someone else.
112  *
113  * The page of the record is mapped using map_mft_record_page() before being
114  * returned to the caller.
115  *
116  * This in turn uses ntfs_map_page() to get the page containing the wanted mft
117  * record (it in turn calls read_cache_page() which reads it in from disk if
118  * necessary, increments the use count on the page so that it cannot disappear
119  * under us and returns a reference to the page cache page).
120  *
121  * If read_cache_page() invokes ntfs_readpage() to load the page from disk, it
122  * sets PG_locked and clears PG_uptodate on the page. Once I/O has completed
123  * and the post-read mst fixups on each mft record in the page have been
124  * performed, the page gets PG_uptodate set and PG_locked cleared (this is done
125  * in our asynchronous I/O completion handler end_buffer_read_mft_async()).
126  * ntfs_map_page() waits for PG_locked to become clear and checks if
127  * PG_uptodate is set and returns an error code if not. This provides
128  * sufficient protection against races when reading/using the page.
129  *
130  * However there is the write mapping to think about. Doing the above described
131  * checking here will be fine, because when initiating the write we will set
132  * PG_locked and clear PG_uptodate making sure nobody is touching the page
133  * contents. Doing the locking this way means that the commit to disk code in
134  * the page cache code paths is automatically sufficiently locked with us as
135  * we will not touch a page that has been locked or is not uptodate. The only
136  * locking problem then is them locking the page while we are accessing it.
137  *
138  * So that code will end up having to own the mrec_lock of all mft
139  * records/inodes present in the page before I/O can proceed. In that case we
140  * wouldn't need to bother with PG_locked and PG_uptodate as nobody will be
141  * accessing anything without owning the mrec_lock mutex.  But we do need to
142  * use them because of the read_cache_page() invocation and the code becomes so
143  * much simpler this way that it is well worth it.
144  *
145  * The mft record is now ours and we return a pointer to it. You need to check
146  * the returned pointer with IS_ERR() and if that is true, PTR_ERR() will return
147  * the error code.
148  *
149  * NOTE: Caller is responsible for setting the mft record dirty before calling
150  * unmap_mft_record(). This is obviously only necessary if the caller really
151  * modified the mft record...
152  * Q: Do we want to recycle one of the VFS inode state bits instead?
153  * A: No, the inode ones mean we want to change the mft record, not we want to
154  * write it out.
155  */
156 MFT_RECORD *map_mft_record(ntfs_inode *ni)
157 {
158         MFT_RECORD *m;
159 
160         ntfs_debug("Entering for mft_no 0x%lx.", ni->mft_no);
161 
162         /* Make sure the ntfs inode doesn't go away. */
163         atomic_inc(&ni->count);
164 
165         /* Serialize access to this mft record. */
166         mutex_lock(&ni->mrec_lock);
167 
168         m = map_mft_record_page(ni);
169         if (likely(!IS_ERR(m)))
170                 return m;
171 
172         mutex_unlock(&ni->mrec_lock);
173         atomic_dec(&ni->count);
174         ntfs_error(ni->vol->sb, "Failed with error code %lu.", -PTR_ERR(m));
175         return m;
176 }
177 
178 /**
179  * unmap_mft_record_page - unmap the page in which a specific mft record resides
180  * @ni:         ntfs inode whose mft record page to unmap
181  *
182  * This unmaps the page in which the mft record of the ntfs inode @ni is
183  * situated and returns. This is a NOOP if highmem is not configured.
184  *
185  * The unmap happens via ntfs_unmap_page() which in turn decrements the use
186  * count on the page thus releasing it from the pinned state.
187  *
188  * We do not actually unmap the page from memory of course, as that will be
189  * done by the page cache code itself when memory pressure increases or
190  * whatever.
191  */
192 static inline void unmap_mft_record_page(ntfs_inode *ni)
193 {
194         BUG_ON(!ni->page);
195 
196         // TODO: If dirty, blah...
197         ntfs_unmap_page(ni->page);
198         ni->page = NULL;
199         ni->page_ofs = 0;
200         return;
201 }
202 
203 /**
204  * unmap_mft_record - release a mapped mft record
205  * @ni:         ntfs inode whose MFT record to unmap
206  *
207  * We release the page mapping and the mrec_lock mutex which unmaps the mft
208  * record and releases it for others to get hold of. We also release the ntfs
209  * inode by decrementing the ntfs inode reference count.
210  *
211  * NOTE: If caller has modified the mft record, it is imperative to set the mft
212  * record dirty BEFORE calling unmap_mft_record().
213  */
214 void unmap_mft_record(ntfs_inode *ni)
215 {
216         struct page *page = ni->page;
217 
218         BUG_ON(!page);
219 
220         ntfs_debug("Entering for mft_no 0x%lx.", ni->mft_no);
221 
222         unmap_mft_record_page(ni);
223         mutex_unlock(&ni->mrec_lock);
224         atomic_dec(&ni->count);
225         /*
226          * If pure ntfs_inode, i.e. no vfs inode attached, we leave it to
227          * ntfs_clear_extent_inode() in the extent inode case, and to the
228          * caller in the non-extent, yet pure ntfs inode case, to do the actual
229          * tear down of all structures and freeing of all allocated memory.
230          */
231         return;
232 }
233 
234 /**
235  * map_extent_mft_record - load an extent inode and attach it to its base
236  * @base_ni:    base ntfs inode
237  * @mref:       mft reference of the extent inode to load
238  * @ntfs_ino:   on successful return, pointer to the ntfs_inode structure
239  *
240  * Load the extent mft record @mref and attach it to its base inode @base_ni.
241  * Return the mapped extent mft record if IS_ERR(result) is false.  Otherwise
242  * PTR_ERR(result) gives the negative error code.
243  *
244  * On successful return, @ntfs_ino contains a pointer to the ntfs_inode
245  * structure of the mapped extent inode.
246  */
247 MFT_RECORD *map_extent_mft_record(ntfs_inode *base_ni, MFT_REF mref,
248                 ntfs_inode **ntfs_ino)
249 {
250         MFT_RECORD *m;
251         ntfs_inode *ni = NULL;
252         ntfs_inode **extent_nis = NULL;
253         int i;
254         unsigned long mft_no = MREF(mref);
255         u16 seq_no = MSEQNO(mref);
256         bool destroy_ni = false;
257 
258         ntfs_debug("Mapping extent mft record 0x%lx (base mft record 0x%lx).",
259                         mft_no, base_ni->mft_no);
260         /* Make sure the base ntfs inode doesn't go away. */
261         atomic_inc(&base_ni->count);
262         /*
263          * Check if this extent inode has already been added to the base inode,
264          * in which case just return it. If not found, add it to the base
265          * inode before returning it.
266          */
267         mutex_lock(&base_ni->extent_lock);
268         if (base_ni->nr_extents > 0) {
269                 extent_nis = base_ni->ext.extent_ntfs_inos;
270                 for (i = 0; i < base_ni->nr_extents; i++) {
271                         if (mft_no != extent_nis[i]->mft_no)
272                                 continue;
273                         ni = extent_nis[i];
274                         /* Make sure the ntfs inode doesn't go away. */
275                         atomic_inc(&ni->count);
276                         break;
277                 }
278         }
279         if (likely(ni != NULL)) {
280                 mutex_unlock(&base_ni->extent_lock);
281                 atomic_dec(&base_ni->count);
282                 /* We found the record; just have to map and return it. */
283                 m = map_mft_record(ni);
284                 /* map_mft_record() has incremented this on success. */
285                 atomic_dec(&ni->count);
286                 if (likely(!IS_ERR(m))) {
287                         /* Verify the sequence number. */
288                         if (likely(le16_to_cpu(m->sequence_number) == seq_no)) {
289                                 ntfs_debug("Done 1.");
290                                 *ntfs_ino = ni;
291                                 return m;
292                         }
293                         unmap_mft_record(ni);
294                         ntfs_error(base_ni->vol->sb, "Found stale extent mft "
295                                         "reference! Corrupt filesystem. "
296                                         "Run chkdsk.");
297                         return ERR_PTR(-EIO);
298                 }
299 map_err_out:
300                 ntfs_error(base_ni->vol->sb, "Failed to map extent "
301                                 "mft record, error code %ld.", -PTR_ERR(m));
302                 return m;
303         }
304         /* Record wasn't there. Get a new ntfs inode and initialize it. */
305         ni = ntfs_new_extent_inode(base_ni->vol->sb, mft_no);
306         if (unlikely(!ni)) {
307                 mutex_unlock(&base_ni->extent_lock);
308                 atomic_dec(&base_ni->count);
309                 return ERR_PTR(-ENOMEM);
310         }
311         ni->vol = base_ni->vol;
312         ni->seq_no = seq_no;
313         ni->nr_extents = -1;
314         ni->ext.base_ntfs_ino = base_ni;
315         /* Now map the record. */
316         m = map_mft_record(ni);
317         if (IS_ERR(m)) {
318                 mutex_unlock(&base_ni->extent_lock);
319                 atomic_dec(&base_ni->count);
320                 ntfs_clear_extent_inode(ni);
321                 goto map_err_out;
322         }
323         /* Verify the sequence number if it is present. */
324         if (seq_no && (le16_to_cpu(m->sequence_number) != seq_no)) {
325                 ntfs_error(base_ni->vol->sb, "Found stale extent mft "
326                                 "reference! Corrupt filesystem. Run chkdsk.");
327                 destroy_ni = true;
328                 m = ERR_PTR(-EIO);
329                 goto unm_err_out;
330         }
331         /* Attach extent inode to base inode, reallocating memory if needed. */
332         if (!(base_ni->nr_extents & 3)) {
333                 ntfs_inode **tmp;
334                 int new_size = (base_ni->nr_extents + 4) * sizeof(ntfs_inode *);
335 
336                 tmp = kmalloc(new_size, GFP_NOFS);
337                 if (unlikely(!tmp)) {
338                         ntfs_error(base_ni->vol->sb, "Failed to allocate "
339                                         "internal buffer.");
340                         destroy_ni = true;
341                         m = ERR_PTR(-ENOMEM);
342                         goto unm_err_out;
343                 }
344                 if (base_ni->nr_extents) {
345                         BUG_ON(!base_ni->ext.extent_ntfs_inos);
346                         memcpy(tmp, base_ni->ext.extent_ntfs_inos, new_size -
347                                         4 * sizeof(ntfs_inode *));
348                         kfree(base_ni->ext.extent_ntfs_inos);
349                 }
350                 base_ni->ext.extent_ntfs_inos = tmp;
351         }
352         base_ni->ext.extent_ntfs_inos[base_ni->nr_extents++] = ni;
353         mutex_unlock(&base_ni->extent_lock);
354         atomic_dec(&base_ni->count);
355         ntfs_debug("Done 2.");
356         *ntfs_ino = ni;
357         return m;
358 unm_err_out:
359         unmap_mft_record(ni);
360         mutex_unlock(&base_ni->extent_lock);
361         atomic_dec(&base_ni->count);
362         /*
363          * If the extent inode was not attached to the base inode we need to
364          * release it or we will leak memory.
365          */
366         if (destroy_ni)
367                 ntfs_clear_extent_inode(ni);
368         return m;
369 }
370 
371 #ifdef NTFS_RW
372 
373 /**
374  * __mark_mft_record_dirty - set the mft record and the page containing it dirty
375  * @ni:         ntfs inode describing the mapped mft record
376  *
377  * Internal function.  Users should call mark_mft_record_dirty() instead.
378  *
379  * Set the mapped (extent) mft record of the (base or extent) ntfs inode @ni,
380  * as well as the page containing the mft record, dirty.  Also, mark the base
381  * vfs inode dirty.  This ensures that any changes to the mft record are
382  * written out to disk.
383  *
384  * NOTE:  We only set I_DIRTY_SYNC and I_DIRTY_DATASYNC (and not I_DIRTY_PAGES)
385  * on the base vfs inode, because even though file data may have been modified,
386  * it is dirty in the inode meta data rather than the data page cache of the
387  * inode, and thus there are no data pages that need writing out.  Therefore, a
388  * full mark_inode_dirty() is overkill.  A mark_inode_dirty_sync(), on the
389  * other hand, is not sufficient, because ->write_inode needs to be called even
390  * in case of fdatasync. This needs to happen or the file data would not
391  * necessarily hit the device synchronously, even though the vfs inode has the
392  * O_SYNC flag set.  Also, I_DIRTY_DATASYNC simply "feels" better than just
393  * I_DIRTY_SYNC, since the file data has not actually hit the block device yet,
394  * which is not what I_DIRTY_SYNC on its own would suggest.
395  */
396 void __mark_mft_record_dirty(ntfs_inode *ni)
397 {
398         ntfs_inode *base_ni;
399 
400         ntfs_debug("Entering for inode 0x%lx.", ni->mft_no);
401         BUG_ON(NInoAttr(ni));
402         mark_ntfs_record_dirty(ni->page, ni->page_ofs);
403         /* Determine the base vfs inode and mark it dirty, too. */
404         mutex_lock(&ni->extent_lock);
405         if (likely(ni->nr_extents >= 0))
406                 base_ni = ni;
407         else
408                 base_ni = ni->ext.base_ntfs_ino;
409         mutex_unlock(&ni->extent_lock);
410         __mark_inode_dirty(VFS_I(base_ni), I_DIRTY_SYNC | I_DIRTY_DATASYNC);
411 }
412 
413 static const char *ntfs_please_email = "Please email "
414                 "linux-ntfs-dev@lists.sourceforge.net and say that you saw "
415                 "this message.  Thank you.";
416 
417 /**
418  * ntfs_sync_mft_mirror_umount - synchronise an mft record to the mft mirror
419  * @vol:        ntfs volume on which the mft record to synchronize resides
420  * @mft_no:     mft record number of mft record to synchronize
421  * @m:          mapped, mst protected (extent) mft record to synchronize
422  *
423  * Write the mapped, mst protected (extent) mft record @m with mft record
424  * number @mft_no to the mft mirror ($MFTMirr) of the ntfs volume @vol,
425  * bypassing the page cache and the $MFTMirr inode itself.
426  *
427  * This function is only for use at umount time when the mft mirror inode has
428  * already been disposed off.  We BUG() if we are called while the mft mirror
429  * inode is still attached to the volume.
430  *
431  * On success return 0.  On error return -errno.
432  *
433  * NOTE:  This function is not implemented yet as I am not convinced it can
434  * actually be triggered considering the sequence of commits we do in super.c::
435  * ntfs_put_super().  But just in case we provide this place holder as the
436  * alternative would be either to BUG() or to get a NULL pointer dereference
437  * and Oops.
438  */
439 static int ntfs_sync_mft_mirror_umount(ntfs_volume *vol,
440                 const unsigned long mft_no, MFT_RECORD *m)
441 {
442         BUG_ON(vol->mftmirr_ino);
443         ntfs_error(vol->sb, "Umount time mft mirror syncing is not "
444                         "implemented yet.  %s", ntfs_please_email);
445         return -EOPNOTSUPP;
446 }
447 
448 /**
449  * ntfs_sync_mft_mirror - synchronize an mft record to the mft mirror
450  * @vol:        ntfs volume on which the mft record to synchronize resides
451  * @mft_no:     mft record number of mft record to synchronize
452  * @m:          mapped, mst protected (extent) mft record to synchronize
453  * @sync:       if true, wait for i/o completion
454  *
455  * Write the mapped, mst protected (extent) mft record @m with mft record
456  * number @mft_no to the mft mirror ($MFTMirr) of the ntfs volume @vol.
457  *
458  * On success return 0.  On error return -errno and set the volume errors flag
459  * in the ntfs volume @vol.
460  *
461  * NOTE:  We always perform synchronous i/o and ignore the @sync parameter.
462  *
463  * TODO:  If @sync is false, want to do truly asynchronous i/o, i.e. just
464  * schedule i/o via ->writepage or do it via kntfsd or whatever.
465  */
466 int ntfs_sync_mft_mirror(ntfs_volume *vol, const unsigned long mft_no,
467                 MFT_RECORD *m, int sync)
468 {
469         struct page *page;
470         unsigned int blocksize = vol->sb->s_blocksize;
471         int max_bhs = vol->mft_record_size / blocksize;
472         struct buffer_head *bhs[max_bhs];
473         struct buffer_head *bh, *head;
474         u8 *kmirr;
475         runlist_element *rl;
476         unsigned int block_start, block_end, m_start, m_end, page_ofs;
477         int i_bhs, nr_bhs, err = 0;
478         unsigned char blocksize_bits = vol->sb->s_blocksize_bits;
479 
480         ntfs_debug("Entering for inode 0x%lx.", mft_no);
481         BUG_ON(!max_bhs);
482         if (unlikely(!vol->mftmirr_ino)) {
483                 /* This could happen during umount... */
484                 err = ntfs_sync_mft_mirror_umount(vol, mft_no, m);
485                 if (likely(!err))
486                         return err;
487                 goto err_out;
488         }
489         /* Get the page containing the mirror copy of the mft record @m. */
490         page = ntfs_map_page(vol->mftmirr_ino->i_mapping, mft_no >>
491                         (PAGE_SHIFT - vol->mft_record_size_bits));
492         if (IS_ERR(page)) {
493                 ntfs_error(vol->sb, "Failed to map mft mirror page.");
494                 err = PTR_ERR(page);
495                 goto err_out;
496         }
497         lock_page(page);
498         BUG_ON(!PageUptodate(page));
499         ClearPageUptodate(page);
500         /* Offset of the mft mirror record inside the page. */
501         page_ofs = (mft_no << vol->mft_record_size_bits) & ~PAGE_MASK;
502         /* The address in the page of the mirror copy of the mft record @m. */
503         kmirr = page_address(page) + page_ofs;
504         /* Copy the mst protected mft record to the mirror. */
505         memcpy(kmirr, m, vol->mft_record_size);
506         /* Create uptodate buffers if not present. */
507         if (unlikely(!page_has_buffers(page))) {
508                 struct buffer_head *tail;
509 
510                 bh = head = alloc_page_buffers(page, blocksize, 1);
511                 do {
512                         set_buffer_uptodate(bh);
513                         tail = bh;
514                         bh = bh->b_this_page;
515                 } while (bh);
516                 tail->b_this_page = head;
517                 attach_page_buffers(page, head);
518         }
519         bh = head = page_buffers(page);
520         BUG_ON(!bh);
521         rl = NULL;
522         nr_bhs = 0;
523         block_start = 0;
524         m_start = kmirr - (u8*)page_address(page);
525         m_end = m_start + vol->mft_record_size;
526         do {
527                 block_end = block_start + blocksize;
528                 /* If the buffer is outside the mft record, skip it. */
529                 if (block_end <= m_start)
530                         continue;
531                 if (unlikely(block_start >= m_end))
532                         break;
533                 /* Need to map the buffer if it is not mapped already. */
534                 if (unlikely(!buffer_mapped(bh))) {
535                         VCN vcn;
536                         LCN lcn;
537                         unsigned int vcn_ofs;
538 
539                         bh->b_bdev = vol->sb->s_bdev;
540                         /* Obtain the vcn and offset of the current block. */
541                         vcn = ((VCN)mft_no << vol->mft_record_size_bits) +
542                                         (block_start - m_start);
543                         vcn_ofs = vcn & vol->cluster_size_mask;
544                         vcn >>= vol->cluster_size_bits;
545                         if (!rl) {
546                                 down_read(&NTFS_I(vol->mftmirr_ino)->
547                                                 runlist.lock);
548                                 rl = NTFS_I(vol->mftmirr_ino)->runlist.rl;
549                                 /*
550                                  * $MFTMirr always has the whole of its runlist
551                                  * in memory.
552                                  */
553                                 BUG_ON(!rl);
554                         }
555                         /* Seek to element containing target vcn. */
556                         while (rl->length && rl[1].vcn <= vcn)
557                                 rl++;
558                         lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
559                         /* For $MFTMirr, only lcn >= 0 is a successful remap. */
560                         if (likely(lcn >= 0)) {
561                                 /* Setup buffer head to correct block. */
562                                 bh->b_blocknr = ((lcn <<
563                                                 vol->cluster_size_bits) +
564                                                 vcn_ofs) >> blocksize_bits;
565                                 set_buffer_mapped(bh);
566                         } else {
567                                 bh->b_blocknr = -1;
568                                 ntfs_error(vol->sb, "Cannot write mft mirror "
569                                                 "record 0x%lx because its "
570                                                 "location on disk could not "
571                                                 "be determined (error code "
572                                                 "%lli).", mft_no,
573                                                 (long long)lcn);
574                                 err = -EIO;
575                         }
576                 }
577                 BUG_ON(!buffer_uptodate(bh));
578                 BUG_ON(!nr_bhs && (m_start != block_start));
579                 BUG_ON(nr_bhs >= max_bhs);
580                 bhs[nr_bhs++] = bh;
581                 BUG_ON((nr_bhs >= max_bhs) && (m_end != block_end));
582         } while (block_start = block_end, (bh = bh->b_this_page) != head);
583         if (unlikely(rl))
584                 up_read(&NTFS_I(vol->mftmirr_ino)->runlist.lock);
585         if (likely(!err)) {
586                 /* Lock buffers and start synchronous write i/o on them. */
587                 for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
588                         struct buffer_head *tbh = bhs[i_bhs];
589 
590                         if (!trylock_buffer(tbh))
591                                 BUG();
592                         BUG_ON(!buffer_uptodate(tbh));
593                         clear_buffer_dirty(tbh);
594                         get_bh(tbh);
595                         tbh->b_end_io = end_buffer_write_sync;
596                         submit_bh(REQ_OP_WRITE, 0, tbh);
597                 }
598                 /* Wait on i/o completion of buffers. */
599                 for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
600                         struct buffer_head *tbh = bhs[i_bhs];
601 
602                         wait_on_buffer(tbh);
603                         if (unlikely(!buffer_uptodate(tbh))) {
604                                 err = -EIO;
605                                 /*
606                                  * Set the buffer uptodate so the page and
607                                  * buffer states do not become out of sync.
608                                  */
609                                 set_buffer_uptodate(tbh);
610                         }
611                 }
612         } else /* if (unlikely(err)) */ {
613                 /* Clean the buffers. */
614                 for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++)
615                         clear_buffer_dirty(bhs[i_bhs]);
616         }
617         /* Current state: all buffers are clean, unlocked, and uptodate. */
618         /* Remove the mst protection fixups again. */
619         post_write_mst_fixup((NTFS_RECORD*)kmirr);
620         flush_dcache_page(page);
621         SetPageUptodate(page);
622         unlock_page(page);
623         ntfs_unmap_page(page);
624         if (likely(!err)) {
625                 ntfs_debug("Done.");
626         } else {
627                 ntfs_error(vol->sb, "I/O error while writing mft mirror "
628                                 "record 0x%lx!", mft_no);
629 err_out:
630                 ntfs_error(vol->sb, "Failed to synchronize $MFTMirr (error "
631                                 "code %i).  Volume will be left marked dirty "
632                                 "on umount.  Run ntfsfix on the partition "
633                                 "after umounting to correct this.", -err);
634                 NVolSetErrors(vol);
635         }
636         return err;
637 }
638 
639 /**
640  * write_mft_record_nolock - write out a mapped (extent) mft record
641  * @ni:         ntfs inode describing the mapped (extent) mft record
642  * @m:          mapped (extent) mft record to write
643  * @sync:       if true, wait for i/o completion
644  *
645  * Write the mapped (extent) mft record @m described by the (regular or extent)
646  * ntfs inode @ni to backing store.  If the mft record @m has a counterpart in
647  * the mft mirror, that is also updated.
648  *
649  * We only write the mft record if the ntfs inode @ni is dirty and the first
650  * buffer belonging to its mft record is dirty, too.  We ignore the dirty state
651  * of subsequent buffers because we could have raced with
652  * fs/ntfs/aops.c::mark_ntfs_record_dirty().
653  *
654  * On success, clean the mft record and return 0.  On error, leave the mft
655  * record dirty and return -errno.
656  *
657  * NOTE:  We always perform synchronous i/o and ignore the @sync parameter.
658  * However, if the mft record has a counterpart in the mft mirror and @sync is
659  * true, we write the mft record, wait for i/o completion, and only then write
660  * the mft mirror copy.  This ensures that if the system crashes either the mft
661  * or the mft mirror will contain a self-consistent mft record @m.  If @sync is
662  * false on the other hand, we start i/o on both and then wait for completion
663  * on them.  This provides a speedup but no longer guarantees that you will end
664  * up with a self-consistent mft record in the case of a crash but if you asked
665  * for asynchronous writing you probably do not care about that anyway.
666  *
667  * TODO:  If @sync is false, want to do truly asynchronous i/o, i.e. just
668  * schedule i/o via ->writepage or do it via kntfsd or whatever.
669  */
670 int write_mft_record_nolock(ntfs_inode *ni, MFT_RECORD *m, int sync)
671 {
672         ntfs_volume *vol = ni->vol;
673         struct page *page = ni->page;
674         unsigned int blocksize = vol->sb->s_blocksize;
675         unsigned char blocksize_bits = vol->sb->s_blocksize_bits;
676         int max_bhs = vol->mft_record_size / blocksize;
677         struct buffer_head *bhs[max_bhs];
678         struct buffer_head *bh, *head;
679         runlist_element *rl;
680         unsigned int block_start, block_end, m_start, m_end;
681         int i_bhs, nr_bhs, err = 0;
682 
683         ntfs_debug("Entering for inode 0x%lx.", ni->mft_no);
684         BUG_ON(NInoAttr(ni));
685         BUG_ON(!max_bhs);
686         BUG_ON(!PageLocked(page));
687         /*
688          * If the ntfs_inode is clean no need to do anything.  If it is dirty,
689          * mark it as clean now so that it can be redirtied later on if needed.
690          * There is no danger of races since the caller is holding the locks
691          * for the mft record @m and the page it is in.
692          */
693         if (!NInoTestClearDirty(ni))
694                 goto done;
695         bh = head = page_buffers(page);
696         BUG_ON(!bh);
697         rl = NULL;
698         nr_bhs = 0;
699         block_start = 0;
700         m_start = ni->page_ofs;
701         m_end = m_start + vol->mft_record_size;
702         do {
703                 block_end = block_start + blocksize;
704                 /* If the buffer is outside the mft record, skip it. */
705                 if (block_end <= m_start)
706                         continue;
707                 if (unlikely(block_start >= m_end))
708                         break;
709                 /*
710                  * If this block is not the first one in the record, we ignore
711                  * the buffer's dirty state because we could have raced with a
712                  * parallel mark_ntfs_record_dirty().
713                  */
714                 if (block_start == m_start) {
715                         /* This block is the first one in the record. */
716                         if (!buffer_dirty(bh)) {
717                                 BUG_ON(nr_bhs);
718                                 /* Clean records are not written out. */
719                                 break;
720                         }
721                 }
722                 /* Need to map the buffer if it is not mapped already. */
723                 if (unlikely(!buffer_mapped(bh))) {
724                         VCN vcn;
725                         LCN lcn;
726                         unsigned int vcn_ofs;
727 
728                         bh->b_bdev = vol->sb->s_bdev;
729                         /* Obtain the vcn and offset of the current block. */
730                         vcn = ((VCN)ni->mft_no << vol->mft_record_size_bits) +
731                                         (block_start - m_start);
732                         vcn_ofs = vcn & vol->cluster_size_mask;
733                         vcn >>= vol->cluster_size_bits;
734                         if (!rl) {
735                                 down_read(&NTFS_I(vol->mft_ino)->runlist.lock);
736                                 rl = NTFS_I(vol->mft_ino)->runlist.rl;
737                                 BUG_ON(!rl);
738                         }
739                         /* Seek to element containing target vcn. */
740                         while (rl->length && rl[1].vcn <= vcn)
741                                 rl++;
742                         lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
743                         /* For $MFT, only lcn >= 0 is a successful remap. */
744                         if (likely(lcn >= 0)) {
745                                 /* Setup buffer head to correct block. */
746                                 bh->b_blocknr = ((lcn <<
747                                                 vol->cluster_size_bits) +
748                                                 vcn_ofs) >> blocksize_bits;
749                                 set_buffer_mapped(bh);
750                         } else {
751                                 bh->b_blocknr = -1;
752                                 ntfs_error(vol->sb, "Cannot write mft record "
753                                                 "0x%lx because its location "
754                                                 "on disk could not be "
755                                                 "determined (error code %lli).",
756                                                 ni->mft_no, (long long)lcn);
757                                 err = -EIO;
758                         }
759                 }
760                 BUG_ON(!buffer_uptodate(bh));
761                 BUG_ON(!nr_bhs && (m_start != block_start));
762                 BUG_ON(nr_bhs >= max_bhs);
763                 bhs[nr_bhs++] = bh;
764                 BUG_ON((nr_bhs >= max_bhs) && (m_end != block_end));
765         } while (block_start = block_end, (bh = bh->b_this_page) != head);
766         if (unlikely(rl))
767                 up_read(&NTFS_I(vol->mft_ino)->runlist.lock);
768         if (!nr_bhs)
769                 goto done;
770         if (unlikely(err))
771                 goto cleanup_out;
772         /* Apply the mst protection fixups. */
773         err = pre_write_mst_fixup((NTFS_RECORD*)m, vol->mft_record_size);
774         if (err) {
775                 ntfs_error(vol->sb, "Failed to apply mst fixups!");
776                 goto cleanup_out;
777         }
778         flush_dcache_mft_record_page(ni);
779         /* Lock buffers and start synchronous write i/o on them. */
780         for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
781                 struct buffer_head *tbh = bhs[i_bhs];
782 
783                 if (!trylock_buffer(tbh))
784                         BUG();
785                 BUG_ON(!buffer_uptodate(tbh));
786                 clear_buffer_dirty(tbh);
787                 get_bh(tbh);
788                 tbh->b_end_io = end_buffer_write_sync;
789                 submit_bh(REQ_OP_WRITE, 0, tbh);
790         }
791         /* Synchronize the mft mirror now if not @sync. */
792         if (!sync && ni->mft_no < vol->mftmirr_size)
793                 ntfs_sync_mft_mirror(vol, ni->mft_no, m, sync);
794         /* Wait on i/o completion of buffers. */
795         for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
796                 struct buffer_head *tbh = bhs[i_bhs];
797 
798                 wait_on_buffer(tbh);
799                 if (unlikely(!buffer_uptodate(tbh))) {
800                         err = -EIO;
801                         /*
802                          * Set the buffer uptodate so the page and buffer
803                          * states do not become out of sync.
804                          */
805                         if (PageUptodate(page))
806                                 set_buffer_uptodate(tbh);
807                 }
808         }
809         /* If @sync, now synchronize the mft mirror. */
810         if (sync && ni->mft_no < vol->mftmirr_size)
811                 ntfs_sync_mft_mirror(vol, ni->mft_no, m, sync);
812         /* Remove the mst protection fixups again. */
813         post_write_mst_fixup((NTFS_RECORD*)m);
814         flush_dcache_mft_record_page(ni);
815         if (unlikely(err)) {
816                 /* I/O error during writing.  This is really bad! */
817                 ntfs_error(vol->sb, "I/O error while writing mft record "
818                                 "0x%lx!  Marking base inode as bad.  You "
819                                 "should unmount the volume and run chkdsk.",
820                                 ni->mft_no);
821                 goto err_out;
822         }
823 done:
824         ntfs_debug("Done.");
825         return 0;
826 cleanup_out:
827         /* Clean the buffers. */
828         for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++)
829                 clear_buffer_dirty(bhs[i_bhs]);
830 err_out:
831         /*
832          * Current state: all buffers are clean, unlocked, and uptodate.
833          * The caller should mark the base inode as bad so that no more i/o
834          * happens.  ->clear_inode() will still be invoked so all extent inodes
835          * and other allocated memory will be freed.
836          */
837         if (err == -ENOMEM) {
838                 ntfs_error(vol->sb, "Not enough memory to write mft record.  "
839                                 "Redirtying so the write is retried later.");
840                 mark_mft_record_dirty(ni);
841                 err = 0;
842         } else
843                 NVolSetErrors(vol);
844         return err;
845 }
846 
847 /**
848  * ntfs_may_write_mft_record - check if an mft record may be written out
849  * @vol:        [IN]  ntfs volume on which the mft record to check resides
850  * @mft_no:     [IN]  mft record number of the mft record to check
851  * @m:          [IN]  mapped mft record to check
852  * @locked_ni:  [OUT] caller has to unlock this ntfs inode if one is returned
853  *
854  * Check if the mapped (base or extent) mft record @m with mft record number
855  * @mft_no belonging to the ntfs volume @vol may be written out.  If necessary
856  * and possible the ntfs inode of the mft record is locked and the base vfs
857  * inode is pinned.  The locked ntfs inode is then returned in @locked_ni.  The
858  * caller is responsible for unlocking the ntfs inode and unpinning the base
859  * vfs inode.
860  *
861  * Return 'true' if the mft record may be written out and 'false' if not.
862  *
863  * The caller has locked the page and cleared the uptodate flag on it which
864  * means that we can safely write out any dirty mft records that do not have
865  * their inodes in icache as determined by ilookup5() as anyone
866  * opening/creating such an inode would block when attempting to map the mft
867  * record in read_cache_page() until we are finished with the write out.
868  *
869  * Here is a description of the tests we perform:
870  *
871  * If the inode is found in icache we know the mft record must be a base mft
872  * record.  If it is dirty, we do not write it and return 'false' as the vfs
873  * inode write paths will result in the access times being updated which would
874  * cause the base mft record to be redirtied and written out again.  (We know
875  * the access time update will modify the base mft record because Windows
876  * chkdsk complains if the standard information attribute is not in the base
877  * mft record.)
878  *
879  * If the inode is in icache and not dirty, we attempt to lock the mft record
880  * and if we find the lock was already taken, it is not safe to write the mft
881  * record and we return 'false'.
882  *
883  * If we manage to obtain the lock we have exclusive access to the mft record,
884  * which also allows us safe writeout of the mft record.  We then set
885  * @locked_ni to the locked ntfs inode and return 'true'.
886  *
887  * Note we cannot just lock the mft record and sleep while waiting for the lock
888  * because this would deadlock due to lock reversal (normally the mft record is
889  * locked before the page is locked but we already have the page locked here
890  * when we try to lock the mft record).
891  *
892  * If the inode is not in icache we need to perform further checks.
893  *
894  * If the mft record is not a FILE record or it is a base mft record, we can
895  * safely write it and return 'true'.
896  *
897  * We now know the mft record is an extent mft record.  We check if the inode
898  * corresponding to its base mft record is in icache and obtain a reference to
899  * it if it is.  If it is not, we can safely write it and return 'true'.
900  *
901  * We now have the base inode for the extent mft record.  We check if it has an
902  * ntfs inode for the extent mft record attached and if not it is safe to write
903  * the extent mft record and we return 'true'.
904  *
905  * The ntfs inode for the extent mft record is attached to the base inode so we
906  * attempt to lock the extent mft record and if we find the lock was already
907  * taken, it is not safe to write the extent mft record and we return 'false'.
908  *
909  * If we manage to obtain the lock we have exclusive access to the extent mft
910  * record, which also allows us safe writeout of the extent mft record.  We
911  * set the ntfs inode of the extent mft record clean and then set @locked_ni to
912  * the now locked ntfs inode and return 'true'.
913  *
914  * Note, the reason for actually writing dirty mft records here and not just
915  * relying on the vfs inode dirty code paths is that we can have mft records
916  * modified without them ever having actual inodes in memory.  Also we can have
917  * dirty mft records with clean ntfs inodes in memory.  None of the described
918  * cases would result in the dirty mft records being written out if we only
919  * relied on the vfs inode dirty code paths.  And these cases can really occur
920  * during allocation of new mft records and in particular when the
921  * initialized_size of the $MFT/$DATA attribute is extended and the new space
922  * is initialized using ntfs_mft_record_format().  The clean inode can then
923  * appear if the mft record is reused for a new inode before it got written
924  * out.
925  */
926 bool ntfs_may_write_mft_record(ntfs_volume *vol, const unsigned long mft_no,
927                 const MFT_RECORD *m, ntfs_inode **locked_ni)
928 {
929         struct super_block *sb = vol->sb;
930         struct inode *mft_vi = vol->mft_ino;
931         struct inode *vi;
932         ntfs_inode *ni, *eni, **extent_nis;
933         int i;
934         ntfs_attr na;
935 
936         ntfs_debug("Entering for inode 0x%lx.", mft_no);
937         /*
938          * Normally we do not return a locked inode so set @locked_ni to NULL.
939          */
940         BUG_ON(!locked_ni);
941         *locked_ni = NULL;
942         /*
943          * Check if the inode corresponding to this mft record is in the VFS
944          * inode cache and obtain a reference to it if it is.
945          */
946         ntfs_debug("Looking for inode 0x%lx in icache.", mft_no);
947         na.mft_no = mft_no;
948         na.name = NULL;
949         na.name_len = 0;
950         na.type = AT_UNUSED;
951         /*
952          * Optimize inode 0, i.e. $MFT itself, since we have it in memory and
953          * we get here for it rather often.
954          */
955         if (!mft_no) {
956                 /* Balance the below iput(). */
957                 vi = igrab(mft_vi);
958                 BUG_ON(vi != mft_vi);
959         } else {
960                 /*
961                  * Have to use ilookup5_nowait() since ilookup5() waits for the
962                  * inode lock which causes ntfs to deadlock when a concurrent
963                  * inode write via the inode dirty code paths and the page
964                  * dirty code path of the inode dirty code path when writing
965                  * $MFT occurs.
966                  */
967                 vi = ilookup5_nowait(sb, mft_no, (test_t)ntfs_test_inode, &na);
968         }
969         if (vi) {
970                 ntfs_debug("Base inode 0x%lx is in icache.", mft_no);
971                 /* The inode is in icache. */
972                 ni = NTFS_I(vi);
973                 /* Take a reference to the ntfs inode. */
974                 atomic_inc(&ni->count);
975                 /* If the inode is dirty, do not write this record. */
976                 if (NInoDirty(ni)) {
977                         ntfs_debug("Inode 0x%lx is dirty, do not write it.",
978                                         mft_no);
979                         atomic_dec(&ni->count);
980                         iput(vi);
981                         return false;
982                 }
983                 ntfs_debug("Inode 0x%lx is not dirty.", mft_no);
984                 /* The inode is not dirty, try to take the mft record lock. */
985                 if (unlikely(!mutex_trylock(&ni->mrec_lock))) {
986                         ntfs_debug("Mft record 0x%lx is already locked, do "
987                                         "not write it.", mft_no);
988                         atomic_dec(&ni->count);
989                         iput(vi);
990                         return false;
991                 }
992                 ntfs_debug("Managed to lock mft record 0x%lx, write it.",
993                                 mft_no);
994                 /*
995                  * The write has to occur while we hold the mft record lock so
996                  * return the locked ntfs inode.
997                  */
998                 *locked_ni = ni;
999                 return true;
1000         }
1001         ntfs_debug("Inode 0x%lx is not in icache.", mft_no);
1002         /* The inode is not in icache. */
1003         /* Write the record if it is not a mft record (type "FILE"). */
1004         if (!ntfs_is_mft_record(m->magic)) {
1005                 ntfs_debug("Mft record 0x%lx is not a FILE record, write it.",
1006                                 mft_no);
1007                 return true;
1008         }
1009         /* Write the mft record if it is a base inode. */
1010         if (!m->base_mft_record) {
1011                 ntfs_debug("Mft record 0x%lx is a base record, write it.",
1012                                 mft_no);
1013                 return true;
1014         }
1015         /*
1016          * This is an extent mft record.  Check if the inode corresponding to
1017          * its base mft record is in icache and obtain a reference to it if it
1018          * is.
1019          */
1020         na.mft_no = MREF_LE(m->base_mft_record);
1021         ntfs_debug("Mft record 0x%lx is an extent record.  Looking for base "
1022                         "inode 0x%lx in icache.", mft_no, na.mft_no);
1023         if (!na.mft_no) {
1024                 /* Balance the below iput(). */
1025                 vi = igrab(mft_vi);
1026                 BUG_ON(vi != mft_vi);
1027         } else
1028                 vi = ilookup5_nowait(sb, na.mft_no, (test_t)ntfs_test_inode,
1029                                 &na);
1030         if (!vi) {
1031                 /*
1032                  * The base inode is not in icache, write this extent mft
1033                  * record.
1034                  */
1035                 ntfs_debug("Base inode 0x%lx is not in icache, write the "
1036                                 "extent record.", na.mft_no);
1037                 return true;
1038         }
1039         ntfs_debug("Base inode 0x%lx is in icache.", na.mft_no);
1040         /*
1041          * The base inode is in icache.  Check if it has the extent inode
1042          * corresponding to this extent mft record attached.
1043          */
1044         ni = NTFS_I(vi);
1045         mutex_lock(&ni->extent_lock);
1046         if (ni->nr_extents <= 0) {
1047                 /*
1048                  * The base inode has no attached extent inodes, write this
1049                  * extent mft record.
1050                  */
1051                 mutex_unlock(&ni->extent_lock);
1052                 iput(vi);
1053                 ntfs_debug("Base inode 0x%lx has no attached extent inodes, "
1054                                 "write the extent record.", na.mft_no);
1055                 return true;
1056         }
1057         /* Iterate over the attached extent inodes. */
1058         extent_nis = ni->ext.extent_ntfs_inos;
1059         for (eni = NULL, i = 0; i < ni->nr_extents; ++i) {
1060                 if (mft_no == extent_nis[i]->mft_no) {
1061                         /*
1062                          * Found the extent inode corresponding to this extent
1063                          * mft record.
1064                          */
1065                         eni = extent_nis[i];
1066                         break;
1067                 }
1068         }
1069         /*
1070          * If the extent inode was not attached to the base inode, write this
1071          * extent mft record.
1072          */
1073         if (!eni) {
1074                 mutex_unlock(&ni->extent_lock);
1075                 iput(vi);
1076                 ntfs_debug("Extent inode 0x%lx is not attached to its base "
1077                                 "inode 0x%lx, write the extent record.",
1078                                 mft_no, na.mft_no);
1079                 return true;
1080         }
1081         ntfs_debug("Extent inode 0x%lx is attached to its base inode 0x%lx.",
1082                         mft_no, na.mft_no);
1083         /* Take a reference to the extent ntfs inode. */
1084         atomic_inc(&eni->count);
1085         mutex_unlock(&ni->extent_lock);
1086         /*
1087          * Found the extent inode coresponding to this extent mft record.
1088          * Try to take the mft record lock.
1089          */
1090         if (unlikely(!mutex_trylock(&eni->mrec_lock))) {
1091                 atomic_dec(&eni->count);
1092                 iput(vi);
1093                 ntfs_debug("Extent mft record 0x%lx is already locked, do "
1094                                 "not write it.", mft_no);
1095                 return false;
1096         }
1097         ntfs_debug("Managed to lock extent mft record 0x%lx, write it.",
1098                         mft_no);
1099         if (NInoTestClearDirty(eni))
1100                 ntfs_debug("Extent inode 0x%lx is dirty, marking it clean.",
1101                                 mft_no);
1102         /*
1103          * The write has to occur while we hold the mft record lock so return
1104          * the locked extent ntfs inode.
1105          */
1106         *locked_ni = eni;
1107         return true;
1108 }
1109 
1110 static const char *es = "  Leaving inconsistent metadata.  Unmount and run "
1111                 "chkdsk.";
1112 
1113 /**
1114  * ntfs_mft_bitmap_find_and_alloc_free_rec_nolock - see name
1115  * @vol:        volume on which to search for a free mft record
1116  * @base_ni:    open base inode if allocating an extent mft record or NULL
1117  *
1118  * Search for a free mft record in the mft bitmap attribute on the ntfs volume
1119  * @vol.
1120  *
1121  * If @base_ni is NULL start the search at the default allocator position.
1122  *
1123  * If @base_ni is not NULL start the search at the mft record after the base
1124  * mft record @base_ni.
1125  *
1126  * Return the free mft record on success and -errno on error.  An error code of
1127  * -ENOSPC means that there are no free mft records in the currently
1128  * initialized mft bitmap.
1129  *
1130  * Locking: Caller must hold vol->mftbmp_lock for writing.
1131  */
1132 static int ntfs_mft_bitmap_find_and_alloc_free_rec_nolock(ntfs_volume *vol,
1133                 ntfs_inode *base_ni)
1134 {
1135         s64 pass_end, ll, data_pos, pass_start, ofs, bit;
1136         unsigned long flags;
1137         struct address_space *mftbmp_mapping;
1138         u8 *buf, *byte;
1139         struct page *page;
1140         unsigned int page_ofs, size;
1141         u8 pass, b;
1142 
1143         ntfs_debug("Searching for free mft record in the currently "
1144                         "initialized mft bitmap.");
1145         mftbmp_mapping = vol->mftbmp_ino->i_mapping;
1146         /*
1147          * Set the end of the pass making sure we do not overflow the mft
1148          * bitmap.
1149          */
1150         read_lock_irqsave(&NTFS_I(vol->mft_ino)->size_lock, flags);
1151         pass_end = NTFS_I(vol->mft_ino)->allocated_size >>
1152                         vol->mft_record_size_bits;
1153         read_unlock_irqrestore(&NTFS_I(vol->mft_ino)->size_lock, flags);
1154         read_lock_irqsave(&NTFS_I(vol->mftbmp_ino)->size_lock, flags);
1155         ll = NTFS_I(vol->mftbmp_ino)->initialized_size << 3;
1156         read_unlock_irqrestore(&NTFS_I(vol->mftbmp_ino)->size_lock, flags);
1157         if (pass_end > ll)
1158                 pass_end = ll;
1159         pass = 1;
1160         if (!base_ni)
1161                 data_pos = vol->mft_data_pos;
1162         else
1163                 data_pos = base_ni->mft_no + 1;
1164         if (data_pos < 24)
1165                 data_pos = 24;
1166         if (data_pos >= pass_end) {
1167                 data_pos = 24;
1168                 pass = 2;
1169                 /* This happens on a freshly formatted volume. */
1170                 if (data_pos >= pass_end)
1171                         return -ENOSPC;
1172         }
1173         pass_start = data_pos;
1174         ntfs_debug("Starting bitmap search: pass %u, pass_start 0x%llx, "
1175                         "pass_end 0x%llx, data_pos 0x%llx.", pass,
1176                         (long long)pass_start, (long long)pass_end,
1177                         (long long)data_pos);
1178         /* Loop until a free mft record is found. */
1179         for (; pass <= 2;) {
1180                 /* Cap size to pass_end. */
1181                 ofs = data_pos >> 3;
1182                 page_ofs = ofs & ~PAGE_MASK;
1183                 size = PAGE_SIZE - page_ofs;
1184                 ll = ((pass_end + 7) >> 3) - ofs;
1185                 if (size > ll)
1186                         size = ll;
1187                 size <<= 3;
1188                 /*
1189                  * If we are still within the active pass, search the next page
1190                  * for a zero bit.
1191                  */
1192                 if (size) {
1193                         page = ntfs_map_page(mftbmp_mapping,
1194                                         ofs >> PAGE_SHIFT);
1195                         if (IS_ERR(page)) {
1196                                 ntfs_error(vol->sb, "Failed to read mft "
1197                                                 "bitmap, aborting.");
1198                                 return PTR_ERR(page);
1199                         }
1200                         buf = (u8*)page_address(page) + page_ofs;
1201                         bit = data_pos & 7;
1202                         data_pos &= ~7ull;
1203                         ntfs_debug("Before inner for loop: size 0x%x, "
1204                                         "data_pos 0x%llx, bit 0x%llx", size,
1205                                         (long long)data_pos, (long long)bit);
1206                         for (; bit < size && data_pos + bit < pass_end;
1207                                         bit &= ~7ull, bit += 8) {
1208                                 byte = buf + (bit >> 3);
1209                                 if (*byte == 0xff)
1210                                         continue;
1211                                 b = ffz((unsigned long)*byte);
1212                                 if (b < 8 && b >= (bit & 7)) {
1213                                         ll = data_pos + (bit & ~7ull) + b;
1214                                         if (unlikely(ll > (1ll << 32))) {
1215                                                 ntfs_unmap_page(page);
1216                                                 return -ENOSPC;
1217                                         }
1218                                         *byte |= 1 << b;
1219                                         flush_dcache_page(page);
1220                                         set_page_dirty(page);
1221                                         ntfs_unmap_page(page);
1222                                         ntfs_debug("Done.  (Found and "
1223                                                         "allocated mft record "
1224                                                         "0x%llx.)",
1225                                                         (long long)ll);
1226                                         return ll;
1227                                 }
1228                         }
1229                         ntfs_debug("After inner for loop: size 0x%x, "
1230                                         "data_pos 0x%llx, bit 0x%llx", size,
1231                                         (long long)data_pos, (long long)bit);
1232                         data_pos += size;
1233                         ntfs_unmap_page(page);
1234                         /*
1235                          * If the end of the pass has not been reached yet,
1236                          * continue searching the mft bitmap for a zero bit.
1237                          */
1238                         if (data_pos < pass_end)
1239                                 continue;
1240                 }
1241                 /* Do the next pass. */
1242                 if (++pass == 2) {
1243                         /*
1244                          * Starting the second pass, in which we scan the first
1245                          * part of the zone which we omitted earlier.
1246                          */
1247                         pass_end = pass_start;
1248                         data_pos = pass_start = 24;
1249                         ntfs_debug("pass %i, pass_start 0x%llx, pass_end "
1250                                         "0x%llx.", pass, (long long)pass_start,
1251                                         (long long)pass_end);
1252                         if (data_pos >= pass_end)
1253                                 break;
1254                 }
1255         }
1256         /* No free mft records in currently initialized mft bitmap. */
1257         ntfs_debug("Done.  (No free mft records left in currently initialized "
1258                         "mft bitmap.)");
1259         return -ENOSPC;
1260 }
1261 
1262 /**
1263  * ntfs_mft_bitmap_extend_allocation_nolock - extend mft bitmap by a cluster
1264  * @vol:        volume on which to extend the mft bitmap attribute
1265  *
1266  * Extend the mft bitmap attribute on the ntfs volume @vol by one cluster.
1267  *
1268  * Note: Only changes allocated_size, i.e. does not touch initialized_size or
1269  * data_size.
1270  *
1271  * Return 0 on success and -errno on error.
1272  *
1273  * Locking: - Caller must hold vol->mftbmp_lock for writing.
1274  *          - This function takes NTFS_I(vol->mftbmp_ino)->runlist.lock for
1275  *            writing and releases it before returning.
1276  *          - This function takes vol->lcnbmp_lock for writing and releases it
1277  *            before returning.
1278  */
1279 static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
1280 {
1281         LCN lcn;
1282         s64 ll;
1283         unsigned long flags;
1284         struct page *page;
1285         ntfs_inode *mft_ni, *mftbmp_ni;
1286         runlist_element *rl, *rl2 = NULL;
1287         ntfs_attr_search_ctx *ctx = NULL;
1288         MFT_RECORD *mrec;
1289         ATTR_RECORD *a = NULL;
1290         int ret, mp_size;
1291         u32 old_alen = 0;
1292         u8 *b, tb;
1293         struct {
1294                 u8 added_cluster:1;
1295                 u8 added_run:1;
1296                 u8 mp_rebuilt:1;
1297         } status = { 0, 0, 0 };
1298 
1299         ntfs_debug("Extending mft bitmap allocation.");
1300         mft_ni = NTFS_I(vol->mft_ino);
1301         mftbmp_ni = NTFS_I(vol->mftbmp_ino);
1302         /*
1303          * Determine the last lcn of the mft bitmap.  The allocated size of the
1304          * mft bitmap cannot be zero so we are ok to do this.
1305          */
1306         down_write(&mftbmp_ni->runlist.lock);
1307         read_lock_irqsave(&mftbmp_ni->size_lock, flags);
1308         ll = mftbmp_ni->allocated_size;
1309         read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1310         rl = ntfs_attr_find_vcn_nolock(mftbmp_ni,
1311                         (ll - 1) >> vol->cluster_size_bits, NULL);
1312         if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
1313                 up_write(&mftbmp_ni->runlist.lock);
1314                 ntfs_error(vol->sb, "Failed to determine last allocated "
1315                                 "cluster of mft bitmap attribute.");
1316                 if (!IS_ERR(rl))
1317                         ret = -EIO;
1318                 else
1319                         ret = PTR_ERR(rl);
1320                 return ret;
1321         }
1322         lcn = rl->lcn + rl->length;
1323         ntfs_debug("Last lcn of mft bitmap attribute is 0x%llx.",
1324                         (long long)lcn);
1325         /*
1326          * Attempt to get the cluster following the last allocated cluster by
1327          * hand as it may be in the MFT zone so the allocator would not give it
1328          * to us.
1329          */
1330         ll = lcn >> 3;
1331         page = ntfs_map_page(vol->lcnbmp_ino->i_mapping,
1332                         ll >> PAGE_SHIFT);
1333         if (IS_ERR(page)) {
1334                 up_write(&mftbmp_ni->runlist.lock);
1335                 ntfs_error(vol->sb, "Failed to read from lcn bitmap.");
1336                 return PTR_ERR(page);
1337         }
1338         b = (u8*)page_address(page) + (ll & ~PAGE_MASK);
1339         tb = 1 << (lcn & 7ull);
1340         down_write(&vol->lcnbmp_lock);
1341         if (*b != 0xff && !(*b & tb)) {
1342                 /* Next cluster is free, allocate it. */
1343                 *b |= tb;
1344                 flush_dcache_page(page);
1345                 set_page_dirty(page);
1346                 up_write(&vol->lcnbmp_lock);
1347                 ntfs_unmap_page(page);
1348                 /* Update the mft bitmap runlist. */
1349                 rl->length++;
1350                 rl[1].vcn++;
1351                 status.added_cluster = 1;
1352                 ntfs_debug("Appending one cluster to mft bitmap.");
1353         } else {
1354                 up_write(&vol->lcnbmp_lock);
1355                 ntfs_unmap_page(page);
1356                 /* Allocate a cluster from the DATA_ZONE. */
1357                 rl2 = ntfs_cluster_alloc(vol, rl[1].vcn, 1, lcn, DATA_ZONE,
1358                                 true);
1359                 if (IS_ERR(rl2)) {
1360                         up_write(&mftbmp_ni->runlist.lock);
1361                         ntfs_error(vol->sb, "Failed to allocate a cluster for "
1362                                         "the mft bitmap.");
1363                         return PTR_ERR(rl2);
1364                 }
1365                 rl = ntfs_runlists_merge(mftbmp_ni->runlist.rl, rl2);
1366                 if (IS_ERR(rl)) {
1367                         up_write(&mftbmp_ni->runlist.lock);
1368                         ntfs_error(vol->sb, "Failed to merge runlists for mft "
1369                                         "bitmap.");
1370                         if (ntfs_cluster_free_from_rl(vol, rl2)) {
1371                                 ntfs_error(vol->sb, "Failed to deallocate "
1372                                                 "allocated cluster.%s", es);
1373                                 NVolSetErrors(vol);
1374                         }
1375                         ntfs_free(rl2);
1376                         return PTR_ERR(rl);
1377                 }
1378                 mftbmp_ni->runlist.rl = rl;
1379                 status.added_run = 1;
1380                 ntfs_debug("Adding one run to mft bitmap.");
1381                 /* Find the last run in the new runlist. */
1382                 for (; rl[1].length; rl++)
1383                         ;
1384         }
1385         /*
1386          * Update the attribute record as well.  Note: @rl is the last
1387          * (non-terminator) runlist element of mft bitmap.
1388          */
1389         mrec = map_mft_record(mft_ni);
1390         if (IS_ERR(mrec)) {
1391                 ntfs_error(vol->sb, "Failed to map mft record.");
1392                 ret = PTR_ERR(mrec);
1393                 goto undo_alloc;
1394         }
1395         ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1396         if (unlikely(!ctx)) {
1397                 ntfs_error(vol->sb, "Failed to get search context.");
1398                 ret = -ENOMEM;
1399                 goto undo_alloc;
1400         }
1401         ret = ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1402                         mftbmp_ni->name_len, CASE_SENSITIVE, rl[1].vcn, NULL,
1403                         0, ctx);
1404         if (unlikely(ret)) {
1405                 ntfs_error(vol->sb, "Failed to find last attribute extent of "
1406                                 "mft bitmap attribute.");
1407                 if (ret == -ENOENT)
1408                         ret = -EIO;
1409                 goto undo_alloc;
1410         }
1411         a = ctx->attr;
1412         ll = sle64_to_cpu(a->data.non_resident.lowest_vcn);
1413         /* Search back for the previous last allocated cluster of mft bitmap. */
1414         for (rl2 = rl; rl2 > mftbmp_ni->runlist.rl; rl2--) {
1415                 if (ll >= rl2->vcn)
1416                         break;
1417         }
1418         BUG_ON(ll < rl2->vcn);
1419         BUG_ON(ll >= rl2->vcn + rl2->length);
1420         /* Get the size for the new mapping pairs array for this extent. */
1421         mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
1422         if (unlikely(mp_size <= 0)) {
1423                 ntfs_error(vol->sb, "Get size for mapping pairs failed for "
1424                                 "mft bitmap attribute extent.");
1425                 ret = mp_size;
1426                 if (!ret)
1427                         ret = -EIO;
1428                 goto undo_alloc;
1429         }
1430         /* Expand the attribute record if necessary. */
1431         old_alen = le32_to_cpu(a->length);
1432         ret = ntfs_attr_record_resize(ctx->mrec, a, mp_size +
1433                         le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
1434         if (unlikely(ret)) {
1435                 if (ret != -ENOSPC) {
1436                         ntfs_error(vol->sb, "Failed to resize attribute "
1437                                         "record for mft bitmap attribute.");
1438                         goto undo_alloc;
1439                 }
1440                 // TODO: Deal with this by moving this extent to a new mft
1441                 // record or by starting a new extent in a new mft record or by
1442                 // moving other attributes out of this mft record.
1443                 // Note: It will need to be a special mft record and if none of
1444                 // those are available it gets rather complicated...
1445                 ntfs_error(vol->sb, "Not enough space in this mft record to "
1446                                 "accommodate extended mft bitmap attribute "
1447                                 "extent.  Cannot handle this yet.");
1448                 ret = -EOPNOTSUPP;
1449                 goto undo_alloc;
1450         }
1451         status.mp_rebuilt = 1;
1452         /* Generate the mapping pairs array directly into the attr record. */
1453         ret = ntfs_mapping_pairs_build(vol, (u8*)a +
1454                         le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
1455                         mp_size, rl2, ll, -1, NULL);
1456         if (unlikely(ret)) {
1457                 ntfs_error(vol->sb, "Failed to build mapping pairs array for "
1458                                 "mft bitmap attribute.");
1459                 goto undo_alloc;
1460         }
1461         /* Update the highest_vcn. */
1462         a->data.non_resident.highest_vcn = cpu_to_sle64(rl[1].vcn - 1);
1463         /*
1464          * We now have extended the mft bitmap allocated_size by one cluster.
1465          * Reflect this in the ntfs_inode structure and the attribute record.
1466          */
1467         if (a->data.non_resident.lowest_vcn) {
1468                 /*
1469                  * We are not in the first attribute extent, switch to it, but
1470                  * first ensure the changes will make it to disk later.
1471                  */
1472                 flush_dcache_mft_record_page(ctx->ntfs_ino);
1473                 mark_mft_record_dirty(ctx->ntfs_ino);
1474                 ntfs_attr_reinit_search_ctx(ctx);
1475                 ret = ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1476                                 mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL,
1477                                 0, ctx);
1478                 if (unlikely(ret)) {
1479                         ntfs_error(vol->sb, "Failed to find first attribute "
1480                                         "extent of mft bitmap attribute.");
1481                         goto restore_undo_alloc;
1482                 }
1483                 a = ctx->attr;
1484         }
1485         write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1486         mftbmp_ni->allocated_size += vol->cluster_size;
1487         a->data.non_resident.allocated_size =
1488                         cpu_to_sle64(mftbmp_ni->allocated_size);
1489         write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1490         /* Ensure the changes make it to disk. */
1491         flush_dcache_mft_record_page(ctx->ntfs_ino);
1492         mark_mft_record_dirty(ctx->ntfs_ino);
1493         ntfs_attr_put_search_ctx(ctx);
1494         unmap_mft_record(mft_ni);
1495         up_write(&mftbmp_ni->runlist.lock);
1496         ntfs_debug("Done.");
1497         return 0;
1498 restore_undo_alloc:
1499         ntfs_attr_reinit_search_ctx(ctx);
1500         if (ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1501                         mftbmp_ni->name_len, CASE_SENSITIVE, rl[1].vcn, NULL,
1502                         0, ctx)) {
1503                 ntfs_error(vol->sb, "Failed to find last attribute extent of "
1504                                 "mft bitmap attribute.%s", es);
1505                 write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1506                 mftbmp_ni->allocated_size += vol->cluster_size;
1507                 write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1508                 ntfs_attr_put_search_ctx(ctx);
1509                 unmap_mft_record(mft_ni);
1510                 up_write(&mftbmp_ni->runlist.lock);
1511                 /*
1512                  * The only thing that is now wrong is ->allocated_size of the
1513                  * base attribute extent which chkdsk should be able to fix.
1514                  */
1515                 NVolSetErrors(vol);
1516                 return ret;
1517         }
1518         a = ctx->attr;
1519         a->data.non_resident.highest_vcn = cpu_to_sle64(rl[1].vcn - 2);
1520 undo_alloc:
1521         if (status.added_cluster) {
1522                 /* Truncate the last run in the runlist by one cluster. */
1523                 rl->length--;
1524                 rl[1].vcn--;
1525         } else if (status.added_run) {
1526                 lcn = rl->lcn;
1527                 /* Remove the last run from the runlist. */
1528                 rl->lcn = rl[1].lcn;
1529                 rl->length = 0;
1530         }
1531         /* Deallocate the cluster. */
1532         down_write(&vol->lcnbmp_lock);
1533         if (ntfs_bitmap_clear_bit(vol->lcnbmp_ino, lcn)) {
1534                 ntfs_error(vol->sb, "Failed to free allocated cluster.%s", es);
1535                 NVolSetErrors(vol);
1536         }
1537         up_write(&vol->lcnbmp_lock);
1538         if (status.mp_rebuilt) {
1539                 if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
1540                                 a->data.non_resident.mapping_pairs_offset),
1541                                 old_alen - le16_to_cpu(
1542                                 a->data.non_resident.mapping_pairs_offset),
1543                                 rl2, ll, -1, NULL)) {
1544                         ntfs_error(vol->sb, "Failed to restore mapping pairs "
1545                                         "array.%s", es);
1546                         NVolSetErrors(vol);
1547                 }
1548                 if (ntfs_attr_record_resize(ctx->mrec, a, old_alen)) {
1549                         ntfs_error(vol->sb, "Failed to restore attribute "
1550                                         "record.%s", es);
1551                         NVolSetErrors(vol);
1552                 }
1553                 flush_dcache_mft_record_page(ctx->ntfs_ino);
1554                 mark_mft_record_dirty(ctx->ntfs_ino);
1555         }
1556         if (ctx)
1557                 ntfs_attr_put_search_ctx(ctx);
1558         if (!IS_ERR(mrec))
1559                 unmap_mft_record(mft_ni);
1560         up_write(&mftbmp_ni->runlist.lock);
1561         return ret;
1562 }
1563 
1564 /**
1565  * ntfs_mft_bitmap_extend_initialized_nolock - extend mftbmp initialized data
1566  * @vol:        volume on which to extend the mft bitmap attribute
1567  *
1568  * Extend the initialized portion of the mft bitmap attribute on the ntfs
1569  * volume @vol by 8 bytes.
1570  *
1571  * Note:  Only changes initialized_size and data_size, i.e. requires that
1572  * allocated_size is big enough to fit the new initialized_size.
1573  *
1574  * Return 0 on success and -error on error.
1575  *
1576  * Locking: Caller must hold vol->mftbmp_lock for writing.
1577  */
1578 static int ntfs_mft_bitmap_extend_initialized_nolock(ntfs_volume *vol)
1579 {
1580         s64 old_data_size, old_initialized_size;
1581         unsigned long flags;
1582         struct inode *mftbmp_vi;
1583         ntfs_inode *mft_ni, *mftbmp_ni;
1584         ntfs_attr_search_ctx *ctx;
1585         MFT_RECORD *mrec;
1586         ATTR_RECORD *a;
1587         int ret;
1588 
1589         ntfs_debug("Extending mft bitmap initiailized (and data) size.");
1590         mft_ni = NTFS_I(vol->mft_ino);
1591         mftbmp_vi = vol->mftbmp_ino;
1592         mftbmp_ni = NTFS_I(mftbmp_vi);
1593         /* Get the attribute record. */
1594         mrec = map_mft_record(mft_ni);
1595         if (IS_ERR(mrec)) {
1596                 ntfs_error(vol->sb, "Failed to map mft record.");
1597                 return PTR_ERR(mrec);
1598         }
1599         ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1600         if (unlikely(!ctx)) {
1601                 ntfs_error(vol->sb, "Failed to get search context.");
1602                 ret = -ENOMEM;
1603                 goto unm_err_out;
1604         }
1605         ret = ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1606                         mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL, 0, ctx);
1607         if (unlikely(ret)) {
1608                 ntfs_error(vol->sb, "Failed to find first attribute extent of "
1609                                 "mft bitmap attribute.");
1610                 if (ret == -ENOENT)
1611                         ret = -EIO;
1612                 goto put_err_out;
1613         }
1614         a = ctx->attr;
1615         write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1616         old_data_size = i_size_read(mftbmp_vi);
1617         old_initialized_size = mftbmp_ni->initialized_size;
1618         /*
1619          * We can simply update the initialized_size before filling the space
1620          * with zeroes because the caller is holding the mft bitmap lock for
1621          * writing which ensures that no one else is trying to access the data.
1622          */
1623         mftbmp_ni->initialized_size += 8;
1624         a->data.non_resident.initialized_size =
1625                         cpu_to_sle64(mftbmp_ni->initialized_size);
1626         if (mftbmp_ni->initialized_size > old_data_size) {
1627                 i_size_write(mftbmp_vi, mftbmp_ni->initialized_size);
1628                 a->data.non_resident.data_size =
1629                                 cpu_to_sle64(mftbmp_ni->initialized_size);
1630         }
1631         write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1632         /* Ensure the changes make it to disk. */
1633         flush_dcache_mft_record_page(ctx->ntfs_ino);
1634         mark_mft_record_dirty(ctx->ntfs_ino);
1635         ntfs_attr_put_search_ctx(ctx);
1636         unmap_mft_record(mft_ni);
1637         /* Initialize the mft bitmap attribute value with zeroes. */
1638         ret = ntfs_attr_set(mftbmp_ni, old_initialized_size, 8, 0);
1639         if (likely(!ret)) {
1640                 ntfs_debug("Done.  (Wrote eight initialized bytes to mft "
1641                                 "bitmap.");
1642                 return 0;
1643         }
1644         ntfs_error(vol->sb, "Failed to write to mft bitmap.");
1645         /* Try to recover from the error. */
1646         mrec = map_mft_record(mft_ni);
1647         if (IS_ERR(mrec)) {
1648                 ntfs_error(vol->sb, "Failed to map mft record.%s", es);
1649                 NVolSetErrors(vol);
1650                 return ret;
1651         }
1652         ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1653         if (unlikely(!ctx)) {
1654                 ntfs_error(vol->sb, "Failed to get search context.%s", es);
1655                 NVolSetErrors(vol);
1656                 goto unm_err_out;
1657         }
1658         if (ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1659                         mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL, 0, ctx)) {
1660                 ntfs_error(vol->sb, "Failed to find first attribute extent of "
1661                                 "mft bitmap attribute.%s", es);
1662                 NVolSetErrors(vol);
1663 put_err_out:
1664                 ntfs_attr_put_search_ctx(ctx);
1665 unm_err_out:
1666                 unmap_mft_record(mft_ni);
1667                 goto err_out;
1668         }
1669         a = ctx->attr;
1670         write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1671         mftbmp_ni->initialized_size = old_initialized_size;
1672         a->data.non_resident.initialized_size =
1673                         cpu_to_sle64(old_initialized_size);
1674         if (i_size_read(mftbmp_vi) != old_data_size) {
1675                 i_size_write(mftbmp_vi, old_data_size);
1676                 a->data.non_resident.data_size = cpu_to_sle64(old_data_size);
1677         }
1678         write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1679         flush_dcache_mft_record_page(ctx->ntfs_ino);
1680         mark_mft_record_dirty(ctx->ntfs_ino);
1681         ntfs_attr_put_search_ctx(ctx);
1682         unmap_mft_record(mft_ni);
1683 #ifdef DEBUG
1684         read_lock_irqsave(&mftbmp_ni->size_lock, flags);
1685         ntfs_debug("Restored status of mftbmp: allocated_size 0x%llx, "
1686                         "data_size 0x%llx, initialized_size 0x%llx.",
1687                         (long long)mftbmp_ni->allocated_size,
1688                         (long long)i_size_read(mftbmp_vi),
1689                         (long long)mftbmp_ni->initialized_size);
1690         read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1691 #endif /* DEBUG */
1692 err_out:
1693         return ret;
1694 }
1695 
1696 /**
1697  * ntfs_mft_data_extend_allocation_nolock - extend mft data attribute
1698  * @vol:        volume on which to extend the mft data attribute
1699  *
1700  * Extend the mft data attribute on the ntfs volume @vol by 16 mft records
1701  * worth of clusters or if not enough space for this by one mft record worth
1702  * of clusters.
1703  *
1704  * Note:  Only changes allocated_size, i.e. does not touch initialized_size or
1705  * data_size.
1706  *
1707  * Return 0 on success and -errno on error.
1708  *
1709  * Locking: - Caller must hold vol->mftbmp_lock for writing.
1710  *          - This function takes NTFS_I(vol->mft_ino)->runlist.lock for
1711  *            writing and releases it before returning.
1712  *          - This function calls functions which take vol->lcnbmp_lock for
1713  *            writing and release it before returning.
1714  */
1715 static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
1716 {
1717         LCN lcn;
1718         VCN old_last_vcn;
1719         s64 min_nr, nr, ll;
1720         unsigned long flags;
1721         ntfs_inode *mft_ni;
1722         runlist_element *rl, *rl2;
1723         ntfs_attr_search_ctx *ctx = NULL;
1724         MFT_RECORD *mrec;
1725         ATTR_RECORD *a = NULL;
1726         int ret, mp_size;
1727         u32 old_alen = 0;
1728         bool mp_rebuilt = false;
1729 
1730         ntfs_debug("Extending mft data allocation.");
1731         mft_ni = NTFS_I(vol->mft_ino);
1732         /*
1733          * Determine the preferred allocation location, i.e. the last lcn of
1734          * the mft data attribute.  The allocated size of the mft data
1735          * attribute cannot be zero so we are ok to do this.
1736          */
1737         down_write(&mft_ni->runlist.lock);
1738         read_lock_irqsave(&mft_ni->size_lock, flags);
1739         ll = mft_ni->allocated_size;
1740         read_unlock_irqrestore(&mft_ni->size_lock, flags);
1741         rl = ntfs_attr_find_vcn_nolock(mft_ni,
1742                         (ll - 1) >> vol->cluster_size_bits, NULL);
1743         if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
1744                 up_write(&mft_ni->runlist.lock);
1745                 ntfs_error(vol->sb, "Failed to determine last allocated "
1746                                 "cluster of mft data attribute.");
1747                 if (!IS_ERR(rl))
1748                         ret = -EIO;
1749                 else
1750                         ret = PTR_ERR(rl);
1751                 return ret;
1752         }
1753         lcn = rl->lcn + rl->length;
1754         ntfs_debug("Last lcn of mft data attribute is 0x%llx.", (long long)lcn);
1755         /* Minimum allocation is one mft record worth of clusters. */
1756         min_nr = vol->mft_record_size >> vol->cluster_size_bits;
1757         if (!min_nr)
1758                 min_nr = 1;
1759         /* Want to allocate 16 mft records worth of clusters. */
1760         nr = vol->mft_record_size << 4 >> vol->cluster_size_bits;
1761         if (!nr)
1762                 nr = min_nr;
1763         /* Ensure we do not go above 2^32-1 mft records. */
1764         read_lock_irqsave(&mft_ni->size_lock, flags);
1765         ll = mft_ni->allocated_size;
1766         read_unlock_irqrestore(&mft_ni->size_lock, flags);
1767         if (unlikely((ll + (nr << vol->cluster_size_bits)) >>
1768                         vol->mft_record_size_bits >= (1ll << 32))) {
1769                 nr = min_nr;
1770                 if (unlikely((ll + (nr << vol->cluster_size_bits)) >>
1771                                 vol->mft_record_size_bits >= (1ll << 32))) {
1772                         ntfs_warning(vol->sb, "Cannot allocate mft record "
1773                                         "because the maximum number of inodes "
1774                                         "(2^32) has already been reached.");
1775                         up_write(&mft_ni->runlist.lock);
1776                         return -ENOSPC;
1777                 }
1778         }
1779         ntfs_debug("Trying mft data allocation with %s cluster count %lli.",
1780                         nr > min_nr ? "default" : "minimal", (long long)nr);
1781         old_last_vcn = rl[1].vcn;
1782         do {
1783                 rl2 = ntfs_cluster_alloc(vol, old_last_vcn, nr, lcn, MFT_ZONE,
1784                                 true);
1785                 if (likely(!IS_ERR(rl2)))
1786                         break;
1787                 if (PTR_ERR(rl2) != -ENOSPC || nr == min_nr) {
1788                         ntfs_error(vol->sb, "Failed to allocate the minimal "
1789                                         "number of clusters (%lli) for the "
1790                                         "mft data attribute.", (long long)nr);
1791                         up_write(&mft_ni->runlist.lock);
1792                         return PTR_ERR(rl2);
1793                 }
1794                 /*
1795                  * There is not enough space to do the allocation, but there
1796                  * might be enough space to do a minimal allocation so try that
1797                  * before failing.
1798                  */
1799                 nr = min_nr;
1800                 ntfs_debug("Retrying mft data allocation with minimal cluster "
1801                                 "count %lli.", (long long)nr);
1802         } while (1);
1803         rl = ntfs_runlists_merge(mft_ni->runlist.rl, rl2);
1804         if (IS_ERR(rl)) {
1805                 up_write(&mft_ni->runlist.lock);
1806                 ntfs_error(vol->sb, "Failed to merge runlists for mft data "
1807                                 "attribute.");
1808                 if (ntfs_cluster_free_from_rl(vol, rl2)) {
1809                         ntfs_error(vol->sb, "Failed to deallocate clusters "
1810                                         "from the mft data attribute.%s", es);
1811                         NVolSetErrors(vol);
1812                 }
1813                 ntfs_free(rl2);
1814                 return PTR_ERR(rl);
1815         }
1816         mft_ni->runlist.rl = rl;
1817         ntfs_debug("Allocated %lli clusters.", (long long)nr);
1818         /* Find the last run in the new runlist. */
1819         for (; rl[1].length; rl++)
1820                 ;
1821         /* Update the attribute record as well. */
1822         mrec = map_mft_record(mft_ni);
1823         if (IS_ERR(mrec)) {
1824                 ntfs_error(vol->sb, "Failed to map mft record.");
1825                 ret = PTR_ERR(mrec);
1826                 goto undo_alloc;
1827         }
1828         ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1829         if (unlikely(!ctx)) {
1830                 ntfs_error(vol->sb, "Failed to get search context.");
1831                 ret = -ENOMEM;
1832                 goto undo_alloc;
1833         }
1834         ret = ntfs_attr_lookup(mft_ni->type, mft_ni->name, mft_ni->name_len,
1835                         CASE_SENSITIVE, rl[1].vcn, NULL, 0, ctx);
1836         if (unlikely(ret)) {
1837                 ntfs_error(vol->sb, "Failed to find last attribute extent of "
1838                                 "mft data attribute.");
1839                 if (ret == -ENOENT)
1840                         ret = -EIO;
1841                 goto undo_alloc;
1842         }
1843         a = ctx->attr;
1844         ll = sle64_to_cpu(a->data.non_resident.lowest_vcn);
1845         /* Search back for the previous last allocated cluster of mft bitmap. */
1846         for (rl2 = rl; rl2 > mft_ni->runlist.rl; rl2--) {
1847                 if (ll >= rl2->vcn)
1848                         break;
1849         }
1850         BUG_ON(ll < rl2->vcn);
1851         BUG_ON(ll >= rl2->vcn + rl2->length);
1852         /* Get the size for the new mapping pairs array for this extent. */
1853         mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
1854         if (unlikely(mp_size <= 0)) {
1855                 ntfs_error(vol->sb, "Get size for mapping pairs failed for "
1856                                 "mft data attribute extent.");
1857                 ret = mp_size;
1858                 if (!ret)
1859                         ret = -EIO;
1860                 goto undo_alloc;
1861         }
1862         /* Expand the attribute record if necessary. */
1863         old_alen = le32_to_cpu(a->length);
1864         ret = ntfs_attr_record_resize(ctx->mrec, a, mp_size +
1865                         le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
1866         if (unlikely(ret)) {
1867                 if (ret != -ENOSPC) {
1868                         ntfs_error(vol->sb, "Failed to resize attribute "
1869                                         "record for mft data attribute.");
1870                         goto undo_alloc;
1871                 }
1872                 // TODO: Deal with this by moving this extent to a new mft
1873                 // record or by starting a new extent in a new mft record or by
1874                 // moving other attributes out of this mft record.
1875                 // Note: Use the special reserved mft records and ensure that
1876                 // this extent is not required to find the mft record in
1877                 // question.  If no free special records left we would need to
1878                 // move an existing record away, insert ours in its place, and
1879                 // then place the moved record into the newly allocated space
1880                 // and we would then need to update all references to this mft
1881                 // record appropriately.  This is rather complicated...
1882                 ntfs_error(vol->sb, "Not enough space in this mft record to "
1883                                 "accommodate extended mft data attribute "
1884                                 "extent.  Cannot handle this yet.");
1885                 ret = -EOPNOTSUPP;
1886                 goto undo_alloc;
1887         }
1888         mp_rebuilt = true;
1889         /* Generate the mapping pairs array directly into the attr record. */
1890         ret = ntfs_mapping_pairs_build(vol, (u8*)a +
1891                         le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
1892                         mp_size, rl2, ll, -1, NULL);
1893         if (unlikely(ret)) {
1894                 ntfs_error(vol->sb, "Failed to build mapping pairs array of "
1895                                 "mft data attribute.");
1896                 goto undo_alloc;
1897         }
1898         /* Update the highest_vcn. */
1899         a->data.non_resident.highest_vcn = cpu_to_sle64(rl[1].vcn - 1);
1900         /*
1901          * We now have extended the mft data allocated_size by nr clusters.
1902          * Reflect this in the ntfs_inode structure and the attribute record.
1903          * @rl is the last (non-terminator) runlist element of mft data
1904          * attribute.
1905          */
1906         if (a->data.non_resident.lowest_vcn) {
1907                 /*
1908                  * We are not in the first attribute extent, switch to it, but
1909                  * first ensure the changes will make it to disk later.
1910                  */
1911                 flush_dcache_mft_record_page(ctx->ntfs_ino);
1912                 mark_mft_record_dirty(ctx->ntfs_ino);
1913                 ntfs_attr_reinit_search_ctx(ctx);
1914                 ret = ntfs_attr_lookup(mft_ni->type, mft_ni->name,
1915                                 mft_ni->name_len, CASE_SENSITIVE, 0, NULL, 0,
1916                                 ctx);
1917                 if (unlikely(ret)) {
1918                         ntfs_error(vol->sb, "Failed to find first attribute "
1919                                         "extent of mft data attribute.");
1920                         goto restore_undo_alloc;
1921                 }
1922                 a = ctx->attr;
1923         }
1924         write_lock_irqsave(&mft_ni->size_lock, flags);
1925         mft_ni->allocated_size += nr << vol->cluster_size_bits;
1926         a->data.non_resident.allocated_size =
1927                         cpu_to_sle64(mft_ni->allocated_size);
1928         write_unlock_irqrestore(&mft_ni->size_lock, flags);
1929         /* Ensure the changes make it to disk. */
1930         flush_dcache_mft_record_page(ctx->ntfs_ino);
1931         mark_mft_record_dirty(ctx->ntfs_ino);
1932         ntfs_attr_put_search_ctx(ctx);
1933         unmap_mft_record(mft_ni);
1934         up_write(&mft_ni->runlist.lock);
1935         ntfs_debug("Done.");
1936         return 0;
1937 restore_undo_alloc:
1938         ntfs_attr_reinit_search_ctx(ctx);
1939         if (ntfs_attr_lookup(mft_ni->type, mft_ni->name, mft_ni->name_len,
1940                         CASE_SENSITIVE, rl[1].vcn, NULL, 0, ctx)) {
1941                 ntfs_error(vol->sb, "Failed to find last attribute extent of "
1942                                 "mft data attribute.%s", es);
1943                 write_lock_irqsave(&mft_ni->size_lock, flags);
1944                 mft_ni->allocated_size += nr << vol->cluster_size_bits;
1945                 write_unlock_irqrestore(&mft_ni->size_lock, flags);
1946                 ntfs_attr_put_search_ctx(ctx);
1947                 unmap_mft_record(mft_ni);
1948                 up_write(&mft_ni->runlist.lock);
1949                 /*
1950                  * The only thing that is now wrong is ->allocated_size of the
1951                  * base attribute extent which chkdsk should be able to fix.
1952                  */
1953                 NVolSetErrors(vol);
1954                 return ret;
1955         }
1956         ctx->attr->data.non_resident.highest_vcn =
1957                         cpu_to_sle64(old_last_vcn - 1);
1958 undo_alloc:
1959         if (ntfs_cluster_free(mft_ni, old_last_vcn, -1, ctx) < 0) {
1960                 ntfs_error(vol->sb, "Failed to free clusters from mft data "
1961                                 "attribute.%s", es);
1962                 NVolSetErrors(vol);
1963         }
1964         a = ctx->attr;
1965         if (ntfs_rl_truncate_nolock(vol, &mft_ni->runlist, old_last_vcn)) {
1966                 ntfs_error(vol->sb, "Failed to truncate mft data attribute "
1967                                 "runlist.%s", es);
1968                 NVolSetErrors(vol);
1969         }
1970         if (mp_rebuilt && !IS_ERR(ctx->mrec)) {
1971                 if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
1972                                 a->data.non_resident.mapping_pairs_offset),
1973                                 old_alen - le16_to_cpu(
1974                                 a->data.non_resident.mapping_pairs_offset),
1975                                 rl2, ll, -1, NULL)) {
1976                         ntfs_error(vol->sb, "Failed to restore mapping pairs "
1977                                         "array.%s", es);
1978                         NVolSetErrors(vol);
1979                 }
1980                 if (ntfs_attr_record_resize(ctx->mrec, a, old_alen)) {
1981                         ntfs_error(vol->sb, "Failed to restore attribute "
1982                                         "record.%s", es);
1983                         NVolSetErrors(vol);
1984                 }
1985                 flush_dcache_mft_record_page(ctx->ntfs_ino);
1986                 mark_mft_record_dirty(ctx->ntfs_ino);
1987         } else if (IS_ERR(ctx->mrec)) {
1988                 ntfs_error(vol->sb, "Failed to restore attribute search "
1989                                 "context.%s", es);
1990                 NVolSetErrors(vol);
1991         }
1992         if (ctx)
1993                 ntfs_attr_put_search_ctx(ctx);
1994         if (!IS_ERR(mrec))
1995                 unmap_mft_record(mft_ni);
1996         up_write(&mft_ni->runlist.lock);
1997         return ret;
1998 }
1999 
2000 /**
2001  * ntfs_mft_record_layout - layout an mft record into a memory buffer
2002  * @vol:        volume to which the mft record will belong
2003  * @mft_no:     mft reference specifying the mft record number
2004  * @m:          destination buffer of size >= @vol->mft_record_size bytes
2005  *
2006  * Layout an empty, unused mft record with the mft record number @mft_no into
2007  * the buffer @m.  The volume @vol is needed because the mft record structure
2008  * was modified in NTFS 3.1 so we need to know which volume version this mft
2009  * record will be used on.
2010  *
2011  * Return 0 on success and -errno on error.
2012  */
2013 static int ntfs_mft_record_layout(const ntfs_volume *vol, const s64 mft_no,
2014                 MFT_RECORD *m)
2015 {
2016         ATTR_RECORD *a;
2017 
2018         ntfs_debug("Entering for mft record 0x%llx.", (long long)mft_no);
2019         if (mft_no >= (1ll << 32)) {
2020                 ntfs_error(vol->sb, "Mft record number 0x%llx exceeds "
2021                                 "maximum of 2^32.", (long long)mft_no);
2022                 return -ERANGE;
2023         }
2024         /* Start by clearing the whole mft record to gives us a clean slate. */
2025         memset(m, 0, vol->mft_record_size);
2026         /* Aligned to 2-byte boundary. */
2027         if (vol->major_ver < 3 || (vol->major_ver == 3 && !vol->minor_ver))
2028                 m->usa_ofs = cpu_to_le16((sizeof(MFT_RECORD_OLD) + 1) & ~1);
2029         else {
2030                 m->usa_ofs = cpu_to_le16((sizeof(MFT_RECORD) + 1) & ~1);
2031                 /*
2032                  * Set the NTFS 3.1+ specific fields while we know that the
2033                  * volume version is 3.1+.
2034                  */
2035                 m->reserved = 0;
2036                 m->mft_record_number = cpu_to_le32((u32)mft_no);
2037         }
2038         m->magic = magic_FILE;
2039         if (vol->mft_record_size >= NTFS_BLOCK_SIZE)
2040                 m->usa_count = cpu_to_le16(vol->mft_record_size /
2041                                 NTFS_BLOCK_SIZE + 1);
2042         else {
2043                 m->usa_count = cpu_to_le16(1);
2044                 ntfs_warning(vol->sb, "Sector size is bigger than mft record "
2045                                 "size.  Setting usa_count to 1.  If chkdsk "
2046                                 "reports this as corruption, please email "
2047                                 "linux-ntfs-dev@lists.sourceforge.net stating "
2048                                 "that you saw this message and that the "
2049                                 "modified filesystem created was corrupt.  "
2050                                 "Thank you.");
2051         }
2052         /* Set the update sequence number to 1. */
2053         *(le16*)((u8*)m + le16_to_cpu(m->usa_ofs)) = cpu_to_le16(1);
2054         m->lsn = 0;
2055         m->sequence_number = cpu_to_le16(1);
2056         m->link_count = 0;
2057         /*
2058          * Place the attributes straight after the update sequence array,
2059          * aligned to 8-byte boundary.
2060          */
2061         m->attrs_offset = cpu_to_le16((le16_to_cpu(m->usa_ofs) +
2062                         (le16_to_cpu(m->usa_count) << 1) + 7) & ~7);
2063         m->flags = 0;
2064         /*
2065          * Using attrs_offset plus eight bytes (for the termination attribute).
2066          * attrs_offset is already aligned to 8-byte boundary, so no need to
2067          * align again.
2068          */
2069         m->bytes_in_use = cpu_to_le32(le16_to_cpu(m->attrs_offset) + 8);
2070         m->bytes_allocated = cpu_to_le32(vol->mft_record_size);
2071         m->base_mft_record = 0;
2072         m->next_attr_instance = 0;
2073         /* Add the termination attribute. */
2074         a = (ATTR_RECORD*)((u8*)m + le16_to_cpu(m->attrs_offset));
2075         a->type = AT_END;
2076         a->length = 0;
2077         ntfs_debug("Done.");
2078         return 0;
2079 }
2080 
2081 /**
2082  * ntfs_mft_record_format - format an mft record on an ntfs volume
2083  * @vol:        volume on which to format the mft record
2084  * @mft_no:     mft record number to format
2085  *
2086  * Format the mft record @mft_no in $MFT/$DATA, i.e. lay out an empty, unused
2087  * mft record into the appropriate place of the mft data attribute.  This is
2088  * used when extending the mft data attribute.
2089  *
2090  * Return 0 on success and -errno on error.
2091  */
2092 static int ntfs_mft_record_format(const ntfs_volume *vol, const s64 mft_no)
2093 {
2094         loff_t i_size;
2095         struct inode *mft_vi = vol->mft_ino;
2096         struct page *page;
2097         MFT_RECORD *m;
2098         pgoff_t index, end_index;
2099         unsigned int ofs;
2100         int err;
2101 
2102         ntfs_debug("Entering for mft record 0x%llx.", (long long)mft_no);
2103         /*
2104          * The index into the page cache and the offset within the page cache
2105          * page of the wanted mft record.
2106          */
2107         index = mft_no << vol->mft_record_size_bits >> PAGE_SHIFT;
2108         ofs = (mft_no << vol->mft_record_size_bits) & ~PAGE_MASK;
2109         /* The maximum valid index into the page cache for $MFT's data. */
2110         i_size = i_size_read(mft_vi);
2111         end_index = i_size >> PAGE_SHIFT;
2112         if (unlikely(index >= end_index)) {
2113                 if (unlikely(index > end_index || ofs + vol->mft_record_size >=
2114                                 (i_size & ~PAGE_MASK))) {
2115                         ntfs_error(vol->sb, "Tried to format non-existing mft "
2116                                         "record 0x%llx.", (long long)mft_no);
2117                         return -ENOENT;
2118                 }
2119         }
2120         /* Read, map, and pin the page containing the mft record. */
2121         page = ntfs_map_page(mft_vi->i_mapping, index);
2122         if (IS_ERR(page)) {
2123                 ntfs_error(vol->sb, "Failed to map page containing mft record "
2124                                 "to format 0x%llx.", (long long)mft_no);
2125                 return PTR_ERR(page);
2126         }
2127         lock_page(page);
2128         BUG_ON(!PageUptodate(page));
2129         ClearPageUptodate(page);
2130         m = (MFT_RECORD*)((u8*)page_address(page) + ofs);
2131         err = ntfs_mft_record_layout(vol, mft_no, m);
2132         if (unlikely(err)) {
2133                 ntfs_error(vol->sb, "Failed to layout mft record 0x%llx.",
2134                                 (long long)mft_no);
2135                 SetPageUptodate(page);
2136                 unlock_page(page);
2137                 ntfs_unmap_page(page);
2138                 return err;
2139         }
2140         flush_dcache_page(page);
2141         SetPageUptodate(page);
2142         unlock_page(page);
2143         /*
2144          * Make sure the mft record is written out to disk.  We could use
2145          * ilookup5() to check if an inode is in icache and so on but this is
2146          * unnecessary as ntfs_writepage() will write the dirty record anyway.
2147          */
2148         mark_ntfs_record_dirty(page, ofs);
2149         ntfs_unmap_page(page);
2150         ntfs_debug("Done.");
2151         return 0;
2152 }
2153 
2154 /**
2155  * ntfs_mft_record_alloc - allocate an mft record on an ntfs volume
2156  * @vol:        [IN]  volume on which to allocate the mft record
2157  * @mode:       [IN]  mode if want a file or directory, i.e. base inode or 0
2158  * @base_ni:    [IN]  open base inode if allocating an extent mft record or NULL
2159  * @mrec:       [OUT] on successful return this is the mapped mft record
2160  *
2161  * Allocate an mft record in $MFT/$DATA of an open ntfs volume @vol.
2162  *
2163  * If @base_ni is NULL make the mft record a base mft record, i.e. a file or
2164  * direvctory inode, and allocate it at the default allocator position.  In
2165  * this case @mode is the file mode as given to us by the caller.  We in
2166  * particular use @mode to distinguish whether a file or a directory is being
2167  * created (S_IFDIR(mode) and S_IFREG(mode), respectively).
2168  *
2169  * If @base_ni is not NULL make the allocated mft record an extent record,
2170  * allocate it starting at the mft record after the base mft record and attach
2171  * the allocated and opened ntfs inode to the base inode @base_ni.  In this
2172  * case @mode must be 0 as it is meaningless for extent inodes.
2173  *
2174  * You need to check the return value with IS_ERR().  If false, the function
2175  * was successful and the return value is the now opened ntfs inode of the
2176  * allocated mft record.  *@mrec is then set to the allocated, mapped, pinned,
2177  * and locked mft record.  If IS_ERR() is true, the function failed and the
2178  * error code is obtained from PTR_ERR(return value).  *@mrec is undefined in
2179  * this case.
2180  *
2181  * Allocation strategy:
2182  *
2183  * To find a free mft record, we scan the mft bitmap for a zero bit.  To
2184  * optimize this we start scanning at the place specified by @base_ni or if
2185  * @base_ni is NULL we start where we last stopped and we perform wrap around
2186  * when we reach the end.  Note, we do not try to allocate mft records below
2187  * number 24 because numbers 0 to 15 are the defined system files anyway and 16
2188  * to 24 are special in that they are used for storing extension mft records
2189  * for the $DATA attribute of $MFT.  This is required to avoid the possibility
2190  * of creating a runlist with a circular dependency which once written to disk
2191  * can never be read in again.  Windows will only use records 16 to 24 for
2192  * normal files if the volume is completely out of space.  We never use them
2193  * which means that when the volume is really out of space we cannot create any
2194  * more files while Windows can still create up to 8 small files.  We can start
2195  * doing this at some later time, it does not matter much for now.
2196  *
2197  * When scanning the mft bitmap, we only search up to the last allocated mft
2198  * record.  If there are no free records left in the range 24 to number of
2199  * allocated mft records, then we extend the $MFT/$DATA attribute in order to
2200  * create free mft records.  We extend the allocated size of $MFT/$DATA by 16
2201  * records at a time or one cluster, if cluster size is above 16kiB.  If there
2202  * is not sufficient space to do this, we try to extend by a single mft record
2203  * or one cluster, if cluster size is above the mft record size.
2204  *
2205  * No matter how many mft records we allocate, we initialize only the first
2206  * allocated mft record, incrementing mft data size and initialized size
2207  * accordingly, open an ntfs_inode for it and return it to the caller, unless
2208  * there are less than 24 mft records, in which case we allocate and initialize
2209  * mft records until we reach record 24 which we consider as the first free mft
2210  * record for use by normal files.
2211  *
2212  * If during any stage we overflow the initialized data in the mft bitmap, we
2213  * extend the initialized size (and data size) by 8 bytes, allocating another
2214  * cluster if required.  The bitmap data size has to be at least equal to the
2215  * number of mft records in the mft, but it can be bigger, in which case the
2216  * superflous bits are padded with zeroes.
2217  *
2218  * Thus, when we return successfully (IS_ERR() is false), we will have:
2219  *      - initialized / extended the mft bitmap if necessary,
2220  *      - initialized / extended the mft data if necessary,
2221  *      - set the bit corresponding to the mft record being allocated in the
2222  *        mft bitmap,
2223  *      - opened an ntfs_inode for the allocated mft record, and we will have
2224  *      - returned the ntfs_inode as well as the allocated mapped, pinned, and
2225  *        locked mft record.
2226  *
2227  * On error, the volume will be left in a consistent state and no record will
2228  * be allocated.  If rolling back a partial operation fails, we may leave some
2229  * inconsistent metadata in which case we set NVolErrors() so the volume is
2230  * left dirty when unmounted.
2231  *
2232  * Note, this function cannot make use of most of the normal functions, like
2233  * for example for attribute resizing, etc, because when the run list overflows
2234  * the base mft record and an attribute list is used, it is very important that
2235  * the extension mft records used to store the $DATA attribute of $MFT can be
2236  * reached without having to read the information contained inside them, as
2237  * this would make it impossible to find them in the first place after the
2238  * volume is unmounted.  $MFT/$BITMAP probably does not need to follow this
2239  * rule because the bitmap is not essential for finding the mft records, but on
2240  * the other hand, handling the bitmap in this special way would make life
2241  * easier because otherwise there might be circular invocations of functions
2242  * when reading the bitmap.
2243  */
2244 ntfs_inode *ntfs_mft_record_alloc(ntfs_volume *vol, const int mode,
2245                 ntfs_inode *base_ni, MFT_RECORD **mrec)
2246 {
2247         s64 ll, bit, old_data_initialized, old_data_size;
2248         unsigned long flags;
2249         struct inode *vi;
2250         struct page *page;
2251         ntfs_inode *mft_ni, *mftbmp_ni, *ni;
2252         ntfs_attr_search_ctx *ctx;
2253         MFT_RECORD *m;
2254         ATTR_RECORD *a;
2255         pgoff_t index;
2256         unsigned int ofs;
2257         int err;
2258         le16 seq_no, usn;
2259         bool record_formatted = false;
2260 
2261         if (base_ni) {
2262                 ntfs_debug("Entering (allocating an extent mft record for "
2263                                 "base mft record 0x%llx).",
2264                                 (long long)base_ni->mft_no);
2265                 /* @mode and @base_ni are mutually exclusive. */
2266                 BUG_ON(mode);
2267         } else
2268                 ntfs_debug("Entering (allocating a base mft record).");
2269         if (mode) {
2270                 /* @mode and @base_ni are mutually exclusive. */
2271                 BUG_ON(base_ni);
2272                 /* We only support creation of normal files and directories. */
2273                 if (!S_ISREG(mode) && !S_ISDIR(mode))
2274                         return ERR_PTR(-EOPNOTSUPP);
2275         }
2276         BUG_ON(!mrec);
2277         mft_ni = NTFS_I(vol->mft_ino);
2278         mftbmp_ni = NTFS_I(vol->mftbmp_ino);
2279         down_write(&vol->mftbmp_lock);
2280         bit = ntfs_mft_bitmap_find_and_alloc_free_rec_nolock(vol, base_ni);
2281         if (bit >= 0) {
2282                 ntfs_debug("Found and allocated free record (#1), bit 0x%llx.",
2283                                 (long long)bit);
2284                 goto have_alloc_rec;
2285         }
2286         if (bit != -ENOSPC) {
2287                 up_write(&vol->mftbmp_lock);
2288                 return ERR_PTR(bit);
2289         }
2290         /*
2291          * No free mft records left.  If the mft bitmap already covers more
2292          * than the currently used mft records, the next records are all free,
2293          * so we can simply allocate the first unused mft record.
2294          * Note: We also have to make sure that the mft bitmap at least covers
2295          * the first 24 mft records as they are special and whilst they may not
2296          * be in use, we do not allocate from them.
2297          */
2298         read_lock_irqsave(&mft_ni->size_lock, flags);
2299         ll = mft_ni->initialized_size >> vol->mft_record_size_bits;
2300         read_unlock_irqrestore(&mft_ni->size_lock, flags);
2301         read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2302         old_data_initialized = mftbmp_ni->initialized_size;
2303         read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2304         if (old_data_initialized << 3 > ll && old_data_initialized > 3) {
2305                 bit = ll;
2306                 if (bit < 24)
2307                         bit = 24;
2308                 if (unlikely(bit >= (1ll << 32)))
2309                         goto max_err_out;
2310                 ntfs_debug("Found free record (#2), bit 0x%llx.",
2311                                 (long long)bit);
2312                 goto found_free_rec;
2313         }
2314         /*
2315          * The mft bitmap needs to be expanded until it covers the first unused
2316          * mft record that we can allocate.
2317          * Note: The smallest mft record we allocate is mft record 24.
2318          */
2319         bit = old_data_initialized << 3;
2320         if (unlikely(bit >= (1ll << 32)))
2321                 goto max_err_out;
2322         read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2323         old_data_size = mftbmp_ni->allocated_size;
2324         ntfs_debug("Status of mftbmp before extension: allocated_size 0x%llx, "
2325                         "data_size 0x%llx, initialized_size 0x%llx.",
2326                         (long long)old_data_size,
2327                         (long long)i_size_read(vol->mftbmp_ino),
2328                         (long long)old_data_initialized);
2329         read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2330         if (old_data_initialized + 8 > old_data_size) {
2331                 /* Need to extend bitmap by one more cluster. */
2332                 ntfs_debug("mftbmp: initialized_size + 8 > allocated_size.");
2333                 err = ntfs_mft_bitmap_extend_allocation_nolock(vol);
2334                 if (unlikely(err)) {
2335                         up_write(&vol->mftbmp_lock);
2336                         goto err_out;
2337                 }
2338 #ifdef DEBUG
2339                 read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2340                 ntfs_debug("Status of mftbmp after allocation extension: "
2341                                 "allocated_size 0x%llx, data_size 0x%llx, "
2342                                 "initialized_size 0x%llx.",
2343                                 (long long)mftbmp_ni->allocated_size,
2344                                 (long long)i_size_read(vol->mftbmp_ino),
2345                                 (long long)mftbmp_ni->initialized_size);
2346                 read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2347 #endif /* DEBUG */
2348         }
2349         /*
2350          * We now have sufficient allocated space, extend the initialized_size
2351          * as well as the data_size if necessary and fill the new space with
2352          * zeroes.
2353          */
2354         err = ntfs_mft_bitmap_extend_initialized_nolock(vol);
2355         if (unlikely(err)) {
2356                 up_write(&vol->mftbmp_lock);
2357                 goto err_out;
2358         }
2359 #ifdef DEBUG
2360         read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2361         ntfs_debug("Status of mftbmp after initialized extension: "
2362                         "allocated_size 0x%llx, data_size 0x%llx, "
2363                         "initialized_size 0x%llx.",
2364                         (long long)mftbmp_ni->allocated_size,
2365                         (long long)i_size_read(vol->mftbmp_ino),
2366                         (long long)mftbmp_ni->initialized_size);
2367         read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2368 #endif /* DEBUG */
2369         ntfs_debug("Found free record (#3), bit 0x%llx.", (long long)bit);
2370 found_free_rec:
2371         /* @bit is the found free mft record, allocate it in the mft bitmap. */
2372         ntfs_debug("At found_free_rec.");
2373         err = ntfs_bitmap_set_bit(vol->mftbmp_ino, bit);
2374         if (unlikely(err)) {
2375                 ntfs_error(vol->sb, "Failed to allocate bit in mft bitmap.");
2376                 up_write(&vol->mftbmp_lock);
2377                 goto err_out;
2378         }
2379         ntfs_debug("Set bit 0x%llx in mft bitmap.", (long long)bit);
2380 have_alloc_rec:
2381         /*
2382          * The mft bitmap is now uptodate.  Deal with mft data attribute now.
2383          * Note, we keep hold of the mft bitmap lock for writing until all
2384          * modifications to the mft data attribute are complete, too, as they
2385          * will impact decisions for mft bitmap and mft record allocation done
2386          * by a parallel allocation and if the lock is not maintained a
2387          * parallel allocation could allocate the same mft record as this one.
2388          */
2389         ll = (bit + 1) << vol->mft_record_size_bits;
2390         read_lock_irqsave(&mft_ni->size_lock, flags);
2391         old_data_initialized = mft_ni->initialized_size;
2392         read_unlock_irqrestore(&mft_ni->size_lock, flags);
2393         if (ll <= old_data_initialized) {
2394                 ntfs_debug("Allocated mft record already initialized.");
2395                 goto mft_rec_already_initialized;
2396         }
2397         ntfs_debug("Initializing allocated mft record.");
2398         /*
2399          * The mft record is outside the initialized data.  Extend the mft data
2400          * attribute until it covers the allocated record.  The loop is only
2401          * actually traversed more than once when a freshly formatted volume is
2402          * first written to so it optimizes away nicely in the common case.
2403          */
2404         read_lock_irqsave(&mft_ni->size_lock, flags);
2405         ntfs_debug("Status of mft data before extension: "
2406                         "allocated_size 0x%llx, data_size 0x%llx, "
2407                         "initialized_size 0x%llx.",
2408                         (long long)mft_ni->allocated_size,
2409                         (long long)i_size_read(vol->mft_ino),
2410                         (long long)mft_ni->initialized_size);
2411         while (ll > mft_ni->allocated_size) {
2412                 read_unlock_irqrestore(&mft_ni->size_lock, flags);
2413                 err = ntfs_mft_data_extend_allocation_nolock(vol);
2414                 if (unlikely(err)) {
2415                         ntfs_error(vol->sb, "Failed to extend mft data "
2416                                         "allocation.");
2417                         goto undo_mftbmp_alloc_nolock;
2418                 }
2419                 read_lock_irqsave(&mft_ni->size_lock, flags);
2420                 ntfs_debug("Status of mft data after allocation extension: "
2421                                 "allocated_size 0x%llx, data_size 0x%llx, "
2422                                 "initialized_size 0x%llx.",
2423                                 (long long)mft_ni->allocated_size,
2424                                 (long long)i_size_read(vol->mft_ino),
2425                                 (long long)mft_ni->initialized_size);
2426         }
2427         read_unlock_irqrestore(&mft_ni->size_lock, flags);
2428         /*
2429          * Extend mft data initialized size (and data size of course) to reach
2430          * the allocated mft record, formatting the mft records allong the way.
2431          * Note: We only modify the ntfs_inode structure as that is all that is
2432          * needed by ntfs_mft_record_format().  We will update the attribute
2433          * record itself in one fell swoop later on.
2434          */
2435         write_lock_irqsave(&mft_ni->size_lock, flags);
2436         old_data_initialized = mft_ni->initialized_size;
2437         old_data_size = vol->mft_ino->i_size;
2438         while (ll > mft_ni->initialized_size) {
2439                 s64 new_initialized_size, mft_no;
2440                 
2441                 new_initialized_size = mft_ni->initialized_size +
2442                                 vol->mft_record_size;
2443                 mft_no = mft_ni->initialized_size >> vol->mft_record_size_bits;
2444                 if (new_initialized_size > i_size_read(vol->mft_ino))
2445                         i_size_write(vol->mft_ino, new_initialized_size);
2446                 write_unlock_irqrestore(&mft_ni->size_lock, flags);
2447                 ntfs_debug("Initializing mft record 0x%llx.",
2448                                 (long long)mft_no);
2449                 err = ntfs_mft_record_format(vol, mft_no);
2450                 if (unlikely(err)) {
2451                         ntfs_error(vol->sb, "Failed to format mft record.");
2452                         goto undo_data_init;
2453                 }
2454                 write_lock_irqsave(&mft_ni->size_lock, flags);
2455                 mft_ni->initialized_size = new_initialized_size;
2456         }
2457         write_unlock_irqrestore(&mft_ni->size_lock, flags);
2458         record_formatted = true;
2459         /* Update the mft data attribute record to reflect the new sizes. */
2460         m = map_mft_record(mft_ni);
2461         if (IS_ERR(m)) {
2462                 ntfs_error(vol->sb, "Failed to map mft record.");
2463                 err = PTR_ERR(m);
2464                 goto undo_data_init;
2465         }
2466         ctx = ntfs_attr_get_search_ctx(mft_ni, m);
2467         if (unlikely(!ctx)) {
2468                 ntfs_error(vol->sb, "Failed to get search context.");
2469                 err = -ENOMEM;
2470                 unmap_mft_record(mft_ni);
2471                 goto undo_data_init;
2472         }
2473         err = ntfs_attr_lookup(mft_ni->type, mft_ni->name, mft_ni->name_len,
2474                         CASE_SENSITIVE, 0, NULL, 0, ctx);
2475         if (unlikely(err)) {
2476                 ntfs_error(vol->sb, "Failed to find first attribute extent of "
2477                                 "mft data attribute.");
2478                 ntfs_attr_put_search_ctx(ctx);
2479                 unmap_mft_record(mft_ni);
2480                 goto undo_data_init;
2481         }
2482         a = ctx->attr;
2483         read_lock_irqsave(&mft_ni->size_lock, flags);
2484         a->data.non_resident.initialized_size =
2485                         cpu_to_sle64(mft_ni->initialized_size);
2486         a->data.non_resident.data_size =
2487                         cpu_to_sle64(i_size_read(vol->mft_ino));
2488         read_unlock_irqrestore(&mft_ni->size_lock, flags);
2489         /* Ensure the changes make it to disk. */
2490         flush_dcache_mft_record_page(ctx->ntfs_ino);
2491         mark_mft_record_dirty(ctx->ntfs_ino);
2492         ntfs_attr_put_search_ctx(ctx);
2493         unmap_mft_record(mft_ni);
2494         read_lock_irqsave(&mft_ni->size_lock, flags);
2495         ntfs_debug("Status of mft data after mft record initialization: "
2496                         "allocated_size 0x%llx, data_size 0x%llx, "
2497                         "initialized_size 0x%llx.",
2498                         (long long)mft_ni->allocated_size,
2499                         (long long)i_size_read(vol->mft_ino),
2500                         (long long)mft_ni->initialized_size);
2501         BUG_ON(i_size_read(vol->mft_ino) > mft_ni->allocated_size);
2502         BUG_ON(mft_ni->initialized_size > i_size_read(vol->mft_ino));
2503         read_unlock_irqrestore(&mft_ni->size_lock, flags);
2504 mft_rec_already_initialized:
2505         /*
2506          * We can finally drop the mft bitmap lock as the mft data attribute
2507          * has been fully updated.  The only disparity left is that the
2508          * allocated mft record still needs to be marked as in use to match the
2509          * set bit in the mft bitmap but this is actually not a problem since
2510          * this mft record is not referenced from anywhere yet and the fact
2511          * that it is allocated in the mft bitmap means that no-one will try to
2512          * allocate it either.
2513          */
2514         up_write(&vol->mftbmp_lock);
2515         /*
2516          * We now have allocated and initialized the mft record.  Calculate the
2517          * index of and the offset within the page cache page the record is in.
2518          */
2519         index = bit << vol->mft_record_size_bits >> PAGE_SHIFT;
2520         ofs = (bit << vol->mft_record_size_bits) & ~PAGE_MASK;
2521         /* Read, map, and pin the page containing the mft record. */
2522         page = ntfs_map_page(vol->mft_ino->i_mapping, index);
2523         if (IS_ERR(page)) {
2524                 ntfs_error(vol->sb, "Failed to map page containing allocated "
2525                                 "mft record 0x%llx.", (long long)bit);
2526                 err = PTR_ERR(page);
2527                 goto undo_mftbmp_alloc;
2528         }
2529         lock_page(page);
2530         BUG_ON(!PageUptodate(page));
2531         ClearPageUptodate(page);
2532         m = (MFT_RECORD*)((u8*)page_address(page) + ofs);
2533         /* If we just formatted the mft record no need to do it again. */
2534         if (!record_formatted) {
2535                 /* Sanity check that the mft record is really not in use. */
2536                 if (ntfs_is_file_record(m->magic) &&
2537                                 (m->flags & MFT_RECORD_IN_USE)) {
2538                         ntfs_error(vol->sb, "Mft record 0x%llx was marked "
2539                                         "free in mft bitmap but is marked "
2540                                         "used itself.  Corrupt filesystem.  "
2541                                         "Unmount and run chkdsk.",
2542                                         (long long)bit);
2543                         err = -EIO;
2544                         SetPageUptodate(page);
2545                         unlock_page(page);
2546                         ntfs_unmap_page(page);
2547                         NVolSetErrors(vol);
2548                         goto undo_mftbmp_alloc;
2549                 }
2550                 /*
2551                  * We need to (re-)format the mft record, preserving the
2552                  * sequence number if it is not zero as well as the update
2553                  * sequence number if it is not zero or -1 (0xffff).  This
2554                  * means we do not need to care whether or not something went
2555                  * wrong with the previous mft record.
2556                  */
2557                 seq_no = m->sequence_number;
2558                 usn = *(le16*)((u8*)m + le16_to_cpu(m->usa_ofs));
2559                 err = ntfs_mft_record_layout(vol, bit, m);
2560                 if (unlikely(err)) {
2561                         ntfs_error(vol->sb, "Failed to layout allocated mft "
2562                                         "record 0x%llx.", (long long)bit);
2563                         SetPageUptodate(page);
2564                         unlock_page(page);
2565                         ntfs_unmap_page(page);
2566                         goto undo_mftbmp_alloc;
2567                 }
2568                 if (seq_no)
2569                         m->sequence_number = seq_no;
2570                 if (usn && le16_to_cpu(usn) != 0xffff)
2571                         *(le16*)((u8*)m + le16_to_cpu(m->usa_ofs)) = usn;
2572         }
2573         /* Set the mft record itself in use. */
2574         m->flags |= MFT_RECORD_IN_USE;
2575         if (S_ISDIR(mode))
2576                 m->flags |= MFT_RECORD_IS_DIRECTORY;
2577         flush_dcache_page(page);
2578         SetPageUptodate(page);
2579         if (base_ni) {
2580                 MFT_RECORD *m_tmp;
2581 
2582                 /*
2583                  * Setup the base mft record in the extent mft record.  This
2584                  * completes initialization of the allocated extent mft record
2585                  * and we can simply use it with map_extent_mft_record().
2586                  */
2587                 m->base_mft_record = MK_LE_MREF(base_ni->mft_no,
2588                                 base_ni->seq_no);
2589                 /*
2590                  * Allocate an extent inode structure for the new mft record,
2591                  * attach it to the base inode @base_ni and map, pin, and lock
2592                  * its, i.e. the allocated, mft record.
2593                  */
2594                 m_tmp = map_extent_mft_record(base_ni, bit, &ni);
2595                 if (IS_ERR(m_tmp)) {
2596                         ntfs_error(vol->sb, "Failed to map allocated extent "
2597                                         "mft record 0x%llx.", (long long)bit);
2598                         err = PTR_ERR(m_tmp);
2599                         /* Set the mft record itself not in use. */
2600                         m->flags &= cpu_to_le16(
2601                                         ~le16_to_cpu(MFT_RECORD_IN_USE));
2602                         flush_dcache_page(page);
2603                         /* Make sure the mft record is written out to disk. */
2604                         mark_ntfs_record_dirty(page, ofs);
2605                         unlock_page(page);
2606                         ntfs_unmap_page(page);
2607                         goto undo_mftbmp_alloc;
2608                 }
2609                 BUG_ON(m != m_tmp);
2610                 /*
2611                  * Make sure the allocated mft record is written out to disk.
2612                  * No need to set the inode dirty because the caller is going
2613                  * to do that anyway after finishing with the new extent mft
2614                  * record (e.g. at a minimum a new attribute will be added to
2615                  * the mft record.
2616                  */
2617                 mark_ntfs_record_dirty(page, ofs);
2618                 unlock_page(page);
2619                 /*
2620                  * Need to unmap the page since map_extent_mft_record() mapped
2621                  * it as well so we have it mapped twice at the moment.
2622                  */
2623                 ntfs_unmap_page(page);
2624         } else {
2625                 /*
2626                  * Allocate a new VFS inode and set it up.  NOTE: @vi->i_nlink
2627                  * is set to 1 but the mft record->link_count is 0.  The caller
2628                  * needs to bear this in mind.
2629                  */
2630                 vi = new_inode(vol->sb);
2631                 if (unlikely(!vi)) {
2632                         err = -ENOMEM;
2633                         /* Set the mft record itself not in use. */
2634                         m->flags &= cpu_to_le16(
2635                                         ~le16_to_cpu(MFT_RECORD_IN_USE));
2636                         flush_dcache_page(page);
2637                         /* Make sure the mft record is written out to disk. */
2638                         mark_ntfs_record_dirty(page, ofs);
2639                         unlock_page(page);
2640                         ntfs_unmap_page(page);
2641                         goto undo_mftbmp_alloc;
2642                 }
2643                 vi->i_ino = bit;
2644                 /*
2645                  * This is for checking whether an inode has changed w.r.t. a
2646                  * file so that the file can be updated if necessary (compare
2647                  * with f_version).
2648                  */
2649                 vi->i_version = 1;
2650 
2651                 /* The owner and group come from the ntfs volume. */
2652                 vi->i_uid = vol->uid;
2653                 vi->i_gid = vol->gid;
2654 
2655                 /* Initialize the ntfs specific part of @vi. */
2656                 ntfs_init_big_inode(vi);
2657                 ni = NTFS_I(vi);
2658                 /*
2659                  * Set the appropriate mode, attribute type, and name.  For
2660                  * directories, also setup the index values to the defaults.
2661                  */
2662                 if (S_ISDIR(mode)) {
2663                         vi->i_mode = S_IFDIR | S_IRWXUGO;
2664                         vi->i_mode &= ~vol->dmask;
2665 
2666                         NInoSetMstProtected(ni);
2667                         ni->type = AT_INDEX_ALLOCATION;
2668                         ni->name = I30;
2669                         ni->name_len = 4;
2670 
2671                         ni->itype.index.block_size = 4096;
2672                         ni->itype.index.block_size_bits = ntfs_ffs(4096) - 1;
2673                         ni->itype.index.collation_rule = COLLATION_FILE_NAME;
2674                         if (vol->cluster_size <= ni->itype.index.block_size) {
2675                                 ni->itype.index.vcn_size = vol->cluster_size;
2676                                 ni->itype.index.vcn_size_bits =
2677                                                 vol->cluster_size_bits;
2678                         } else {
2679                                 ni->itype.index.vcn_size = vol->sector_size;
2680                                 ni->itype.index.vcn_size_bits =
2681                                                 vol->sector_size_bits;
2682                         }
2683                 } else {
2684                         vi->i_mode = S_IFREG | S_IRWXUGO;
2685                         vi->i_mode &= ~vol->fmask;
2686 
2687                         ni->type = AT_DATA;
2688                         ni->name = NULL;
2689                         ni->name_len = 0;
2690                 }
2691                 if (IS_RDONLY(vi))
2692                         vi->i_mode &= ~S_IWUGO;
2693 
2694                 /* Set the inode times to the current time. */
2695                 vi->i_atime = vi->i_mtime = vi->i_ctime =
2696                         current_time(vi);
2697                 /*
2698                  * Set the file size to 0, the ntfs inode sizes are set to 0 by
2699                  * the call to ntfs_init_big_inode() below.
2700                  */
2701                 vi->i_size = 0;
2702                 vi->i_blocks = 0;
2703 
2704                 /* Set the sequence number. */
2705                 vi->i_generation = ni->seq_no = le16_to_cpu(m->sequence_number);
2706                 /*
2707                  * Manually map, pin, and lock the mft record as we already
2708                  * have its page mapped and it is very easy to do.
2709                  */
2710                 atomic_inc(&ni->count);
2711                 mutex_lock(&ni->mrec_lock);
2712                 ni->page = page;
2713                 ni->page_ofs = ofs;
2714                 /*
2715                  * Make sure the allocated mft record is written out to disk.
2716                  * NOTE: We do not set the ntfs inode dirty because this would
2717                  * fail in ntfs_write_inode() because the inode does not have a
2718                  * standard information attribute yet.  Also, there is no need
2719                  * to set the inode dirty because the caller is going to do
2720                  * that anyway after finishing with the new mft record (e.g. at
2721                  * a minimum some new attributes will be added to the mft
2722                  * record.
2723                  */
2724                 mark_ntfs_record_dirty(page, ofs);
2725                 unlock_page(page);
2726 
2727                 /* Add the inode to the inode hash for the superblock. */
2728                 insert_inode_hash(vi);
2729 
2730                 /* Update the default mft allocation position. */
2731                 vol->mft_data_pos = bit + 1;
2732         }
2733         /*
2734          * Return the opened, allocated inode of the allocated mft record as
2735          * well as the mapped, pinned, and locked mft record.
2736          */
2737         ntfs_debug("Returning opened, allocated %sinode 0x%llx.",
2738                         base_ni ? "extent " : "", (long long)bit);
2739         *mrec = m;
2740         return ni;
2741 undo_data_init:
2742         write_lock_irqsave(&mft_ni->size_lock, flags);
2743         mft_ni->initialized_size = old_data_initialized;
2744         i_size_write(vol->mft_ino, old_data_size);
2745         write_unlock_irqrestore(&mft_ni->size_lock, flags);
2746         goto undo_mftbmp_alloc_nolock;
2747 undo_mftbmp_alloc:
2748         down_write(&vol->mftbmp_lock);
2749 undo_mftbmp_alloc_nolock:
2750         if (ntfs_bitmap_clear_bit(vol->mftbmp_ino, bit)) {
2751                 ntfs_error(vol->sb, "Failed to clear bit in mft bitmap.%s", es);
2752                 NVolSetErrors(vol);
2753         }
2754         up_write(&vol->mftbmp_lock);
2755 err_out:
2756         return ERR_PTR(err);
2757 max_err_out:
2758         ntfs_warning(vol->sb, "Cannot allocate mft record because the maximum "
2759                         "number of inodes (2^32) has already been reached.");
2760         up_write(&vol->mftbmp_lock);
2761         return ERR_PTR(-ENOSPC);
2762 }
2763 
2764 /**
2765  * ntfs_extent_mft_record_free - free an extent mft record on an ntfs volume
2766  * @ni:         ntfs inode of the mapped extent mft record to free
2767  * @m:          mapped extent mft record of the ntfs inode @ni
2768  *
2769  * Free the mapped extent mft record @m of the extent ntfs inode @ni.
2770  *
2771  * Note that this function unmaps the mft record and closes and destroys @ni
2772  * internally and hence you cannot use either @ni nor @m any more after this
2773  * function returns success.
2774  *
2775  * On success return 0 and on error return -errno.  @ni and @m are still valid
2776  * in this case and have not been freed.
2777  *
2778  * For some errors an error message is displayed and the success code 0 is
2779  * returned and the volume is then left dirty on umount.  This makes sense in
2780  * case we could not rollback the changes that were already done since the
2781  * caller no longer wants to reference this mft record so it does not matter to
2782  * the caller if something is wrong with it as long as it is properly detached
2783  * from the base inode.
2784  */
2785 int ntfs_extent_mft_record_free(ntfs_inode *ni, MFT_RECORD *m)
2786 {
2787         unsigned long mft_no = ni->mft_no;
2788         ntfs_volume *vol = ni->vol;
2789         ntfs_inode *base_ni;
2790         ntfs_inode **extent_nis;
2791         int i, err;
2792         le16 old_seq_no;
2793         u16 seq_no;
2794         
2795         BUG_ON(NInoAttr(ni));
2796         BUG_ON(ni->nr_extents != -1);
2797 
2798         mutex_lock(&ni->extent_lock);
2799         base_ni = ni->ext.base_ntfs_ino;
2800         mutex_unlock(&ni->extent_lock);
2801 
2802         BUG_ON(base_ni->nr_extents <= 0);
2803 
2804         ntfs_debug("Entering for extent inode 0x%lx, base inode 0x%lx.\n",
2805                         mft_no, base_ni->mft_no);
2806 
2807         mutex_lock(&base_ni->extent_lock);
2808 
2809         /* Make sure we are holding the only reference to the extent inode. */
2810         if (atomic_read(&ni->count) > 2) {
2811                 ntfs_error(vol->sb, "Tried to free busy extent inode 0x%lx, "
2812                                 "not freeing.", base_ni->mft_no);
2813                 mutex_unlock(&base_ni->extent_lock);
2814                 return -EBUSY;
2815         }
2816 
2817         /* Dissociate the ntfs inode from the base inode. */
2818         extent_nis = base_ni->ext.extent_ntfs_inos;
2819         err = -ENOENT;
2820         for (i = 0; i < base_ni->nr_extents; i++) {
2821                 if (ni != extent_nis[i])
2822                         continue;
2823                 extent_nis += i;
2824                 base_ni->nr_extents--;
2825                 memmove(extent_nis, extent_nis + 1, (base_ni->nr_extents - i) *
2826                                 sizeof(ntfs_inode*));
2827                 err = 0;
2828                 break;
2829         }
2830 
2831         mutex_unlock(&base_ni->extent_lock);
2832 
2833         if (unlikely(err)) {
2834                 ntfs_error(vol->sb, "Extent inode 0x%lx is not attached to "
2835                                 "its base inode 0x%lx.", mft_no,
2836                                 base_ni->mft_no);
2837                 BUG();
2838         }
2839 
2840         /*
2841          * The extent inode is no longer attached to the base inode so no one
2842          * can get a reference to it any more.
2843          */
2844 
2845         /* Mark the mft record as not in use. */
2846         m->flags &= ~MFT_RECORD_IN_USE;
2847 
2848         /* Increment the sequence number, skipping zero, if it is not zero. */
2849         old_seq_no = m->sequence_number;
2850         seq_no = le16_to_cpu(old_seq_no);
2851         if (seq_no == 0xffff)
2852                 seq_no = 1;
2853         else if (seq_no)
2854                 seq_no++;
2855         m->sequence_number = cpu_to_le16(seq_no);
2856 
2857         /*
2858          * Set the ntfs inode dirty and write it out.  We do not need to worry
2859          * about the base inode here since whatever caused the extent mft
2860          * record to be freed is guaranteed to do it already.
2861          */
2862         NInoSetDirty(ni);
2863         err = write_mft_record(ni, m, 0);
2864         if (unlikely(err)) {
2865                 ntfs_error(vol->sb, "Failed to write mft record 0x%lx, not "
2866                                 "freeing.", mft_no);
2867                 goto rollback;
2868         }
2869 rollback_error:
2870         /* Unmap and throw away the now freed extent inode. */
2871         unmap_extent_mft_record(ni);
2872         ntfs_clear_extent_inode(ni);
2873 
2874         /* Clear the bit in the $MFT/$BITMAP corresponding to this record. */
2875         down_write(&vol->mftbmp_lock);
2876         err = ntfs_bitmap_clear_bit(vol->mftbmp_ino, mft_no);
2877         up_write(&vol->mftbmp_lock);
2878         if (unlikely(err)) {
2879                 /*
2880                  * The extent inode is gone but we failed to deallocate it in
2881                  * the mft bitmap.  Just emit a warning and leave the volume
2882                  * dirty on umount.
2883                  */
2884                 ntfs_error(vol->sb, "Failed to clear bit in mft bitmap.%s", es);
2885                 NVolSetErrors(vol);
2886         }
2887         return 0;
2888 rollback:
2889         /* Rollback what we did... */
2890         mutex_lock(&base_ni->extent_lock);
2891         extent_nis = base_ni->ext.extent_ntfs_inos;
2892         if (!(base_ni->nr_extents & 3)) {
2893                 int new_size = (base_ni->nr_extents + 4) * sizeof(ntfs_inode*);
2894 
2895                 extent_nis = kmalloc(new_size, GFP_NOFS);
2896                 if (unlikely(!extent_nis)) {
2897                         ntfs_error(vol->sb, "Failed to allocate internal "
2898                                         "buffer during rollback.%s", es);
2899                         mutex_unlock(&base_ni->extent_lock);
2900                         NVolSetErrors(vol);
2901                         goto rollback_error;
2902                 }
2903                 if (base_ni->nr_extents) {
2904                         BUG_ON(!base_ni->ext.extent_ntfs_inos);
2905                         memcpy(extent_nis, base_ni->ext.extent_ntfs_inos,
2906                                         new_size - 4 * sizeof(ntfs_inode*));
2907                         kfree(base_ni->ext.extent_ntfs_inos);
2908                 }
2909                 base_ni->ext.extent_ntfs_inos = extent_nis;
2910         }
2911         m->flags |= MFT_RECORD_IN_USE;
2912         m->sequence_number = old_seq_no;
2913         extent_nis[base_ni->nr_extents++] = ni;
2914         mutex_unlock(&base_ni->extent_lock);
2915         mark_mft_record_dirty(ni);
2916         return err;
2917 }
2918 #endif /* NTFS_RW */
2919 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp