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

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  1 /**
  2  * dir.c - NTFS kernel directory operations. Part of the Linux-NTFS project.
  3  *
  4  * Copyright (c) 2001-2007 Anton Altaparmakov
  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 
 26 #include "dir.h"
 27 #include "aops.h"
 28 #include "attrib.h"
 29 #include "mft.h"
 30 #include "debug.h"
 31 #include "ntfs.h"
 32 
 33 /**
 34  * The little endian Unicode string $I30 as a global constant.
 35  */
 36 ntfschar I30[5] = { cpu_to_le16('$'), cpu_to_le16('I'),
 37                 cpu_to_le16('3'),       cpu_to_le16(''), 0 };
 38 
 39 /**
 40  * ntfs_lookup_inode_by_name - find an inode in a directory given its name
 41  * @dir_ni:     ntfs inode of the directory in which to search for the name
 42  * @uname:      Unicode name for which to search in the directory
 43  * @uname_len:  length of the name @uname in Unicode characters
 44  * @res:        return the found file name if necessary (see below)
 45  *
 46  * Look for an inode with name @uname in the directory with inode @dir_ni.
 47  * ntfs_lookup_inode_by_name() walks the contents of the directory looking for
 48  * the Unicode name. If the name is found in the directory, the corresponding
 49  * inode number (>= 0) is returned as a mft reference in cpu format, i.e. it
 50  * is a 64-bit number containing the sequence number.
 51  *
 52  * On error, a negative value is returned corresponding to the error code. In
 53  * particular if the inode is not found -ENOENT is returned. Note that you
 54  * can't just check the return value for being negative, you have to check the
 55  * inode number for being negative which you can extract using MREC(return
 56  * value).
 57  *
 58  * Note, @uname_len does not include the (optional) terminating NULL character.
 59  *
 60  * Note, we look for a case sensitive match first but we also look for a case
 61  * insensitive match at the same time. If we find a case insensitive match, we
 62  * save that for the case that we don't find an exact match, where we return
 63  * the case insensitive match and setup @res (which we allocate!) with the mft
 64  * reference, the file name type, length and with a copy of the little endian
 65  * Unicode file name itself. If we match a file name which is in the DOS name
 66  * space, we only return the mft reference and file name type in @res.
 67  * ntfs_lookup() then uses this to find the long file name in the inode itself.
 68  * This is to avoid polluting the dcache with short file names. We want them to
 69  * work but we don't care for how quickly one can access them. This also fixes
 70  * the dcache aliasing issues.
 71  *
 72  * Locking:  - Caller must hold i_mutex on the directory.
 73  *           - Each page cache page in the index allocation mapping must be
 74  *             locked whilst being accessed otherwise we may find a corrupt
 75  *             page due to it being under ->writepage at the moment which
 76  *             applies the mst protection fixups before writing out and then
 77  *             removes them again after the write is complete after which it 
 78  *             unlocks the page.
 79  */
 80 MFT_REF ntfs_lookup_inode_by_name(ntfs_inode *dir_ni, const ntfschar *uname,
 81                 const int uname_len, ntfs_name **res)
 82 {
 83         ntfs_volume *vol = dir_ni->vol;
 84         struct super_block *sb = vol->sb;
 85         MFT_RECORD *m;
 86         INDEX_ROOT *ir;
 87         INDEX_ENTRY *ie;
 88         INDEX_ALLOCATION *ia;
 89         u8 *index_end;
 90         u64 mref;
 91         ntfs_attr_search_ctx *ctx;
 92         int err, rc;
 93         VCN vcn, old_vcn;
 94         struct address_space *ia_mapping;
 95         struct page *page;
 96         u8 *kaddr;
 97         ntfs_name *name = NULL;
 98 
 99         BUG_ON(!S_ISDIR(VFS_I(dir_ni)->i_mode));
100         BUG_ON(NInoAttr(dir_ni));
101         /* Get hold of the mft record for the directory. */
102         m = map_mft_record(dir_ni);
103         if (IS_ERR(m)) {
104                 ntfs_error(sb, "map_mft_record() failed with error code %ld.",
105                                 -PTR_ERR(m));
106                 return ERR_MREF(PTR_ERR(m));
107         }
108         ctx = ntfs_attr_get_search_ctx(dir_ni, m);
109         if (unlikely(!ctx)) {
110                 err = -ENOMEM;
111                 goto err_out;
112         }
113         /* Find the index root attribute in the mft record. */
114         err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE, 0, NULL,
115                         0, ctx);
116         if (unlikely(err)) {
117                 if (err == -ENOENT) {
118                         ntfs_error(sb, "Index root attribute missing in "
119                                         "directory inode 0x%lx.",
120                                         dir_ni->mft_no);
121                         err = -EIO;
122                 }
123                 goto err_out;
124         }
125         /* Get to the index root value (it's been verified in read_inode). */
126         ir = (INDEX_ROOT*)((u8*)ctx->attr +
127                         le16_to_cpu(ctx->attr->data.resident.value_offset));
128         index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
129         /* The first index entry. */
130         ie = (INDEX_ENTRY*)((u8*)&ir->index +
131                         le32_to_cpu(ir->index.entries_offset));
132         /*
133          * Loop until we exceed valid memory (corruption case) or until we
134          * reach the last entry.
135          */
136         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
137                 /* Bounds checks. */
138                 if ((u8*)ie < (u8*)ctx->mrec || (u8*)ie +
139                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
140                                 (u8*)ie + le16_to_cpu(ie->key_length) >
141                                 index_end)
142                         goto dir_err_out;
143                 /*
144                  * The last entry cannot contain a name. It can however contain
145                  * a pointer to a child node in the B+tree so we just break out.
146                  */
147                 if (ie->flags & INDEX_ENTRY_END)
148                         break;
149                 /*
150                  * We perform a case sensitive comparison and if that matches
151                  * we are done and return the mft reference of the inode (i.e.
152                  * the inode number together with the sequence number for
153                  * consistency checking). We convert it to cpu format before
154                  * returning.
155                  */
156                 if (ntfs_are_names_equal(uname, uname_len,
157                                 (ntfschar*)&ie->key.file_name.file_name,
158                                 ie->key.file_name.file_name_length,
159                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len)) {
160 found_it:
161                         /*
162                          * We have a perfect match, so we don't need to care
163                          * about having matched imperfectly before, so we can
164                          * free name and set *res to NULL.
165                          * However, if the perfect match is a short file name,
166                          * we need to signal this through *res, so that
167                          * ntfs_lookup() can fix dcache aliasing issues.
168                          * As an optimization we just reuse an existing
169                          * allocation of *res.
170                          */
171                         if (ie->key.file_name.file_name_type == FILE_NAME_DOS) {
172                                 if (!name) {
173                                         name = kmalloc(sizeof(ntfs_name),
174                                                         GFP_NOFS);
175                                         if (!name) {
176                                                 err = -ENOMEM;
177                                                 goto err_out;
178                                         }
179                                 }
180                                 name->mref = le64_to_cpu(
181                                                 ie->data.dir.indexed_file);
182                                 name->type = FILE_NAME_DOS;
183                                 name->len = 0;
184                                 *res = name;
185                         } else {
186                                 kfree(name);
187                                 *res = NULL;
188                         }
189                         mref = le64_to_cpu(ie->data.dir.indexed_file);
190                         ntfs_attr_put_search_ctx(ctx);
191                         unmap_mft_record(dir_ni);
192                         return mref;
193                 }
194                 /*
195                  * For a case insensitive mount, we also perform a case
196                  * insensitive comparison (provided the file name is not in the
197                  * POSIX namespace). If the comparison matches, and the name is
198                  * in the WIN32 namespace, we cache the filename in *res so
199                  * that the caller, ntfs_lookup(), can work on it. If the
200                  * comparison matches, and the name is in the DOS namespace, we
201                  * only cache the mft reference and the file name type (we set
202                  * the name length to zero for simplicity).
203                  */
204                 if (!NVolCaseSensitive(vol) &&
205                                 ie->key.file_name.file_name_type &&
206                                 ntfs_are_names_equal(uname, uname_len,
207                                 (ntfschar*)&ie->key.file_name.file_name,
208                                 ie->key.file_name.file_name_length,
209                                 IGNORE_CASE, vol->upcase, vol->upcase_len)) {
210                         int name_size = sizeof(ntfs_name);
211                         u8 type = ie->key.file_name.file_name_type;
212                         u8 len = ie->key.file_name.file_name_length;
213 
214                         /* Only one case insensitive matching name allowed. */
215                         if (name) {
216                                 ntfs_error(sb, "Found already allocated name "
217                                                 "in phase 1. Please run chkdsk "
218                                                 "and if that doesn't find any "
219                                                 "errors please report you saw "
220                                                 "this message to "
221                                                 "linux-ntfs-dev@lists."
222                                                 "sourceforge.net.");
223                                 goto dir_err_out;
224                         }
225 
226                         if (type != FILE_NAME_DOS)
227                                 name_size += len * sizeof(ntfschar);
228                         name = kmalloc(name_size, GFP_NOFS);
229                         if (!name) {
230                                 err = -ENOMEM;
231                                 goto err_out;
232                         }
233                         name->mref = le64_to_cpu(ie->data.dir.indexed_file);
234                         name->type = type;
235                         if (type != FILE_NAME_DOS) {
236                                 name->len = len;
237                                 memcpy(name->name, ie->key.file_name.file_name,
238                                                 len * sizeof(ntfschar));
239                         } else
240                                 name->len = 0;
241                         *res = name;
242                 }
243                 /*
244                  * Not a perfect match, need to do full blown collation so we
245                  * know which way in the B+tree we have to go.
246                  */
247                 rc = ntfs_collate_names(uname, uname_len,
248                                 (ntfschar*)&ie->key.file_name.file_name,
249                                 ie->key.file_name.file_name_length, 1,
250                                 IGNORE_CASE, vol->upcase, vol->upcase_len);
251                 /*
252                  * If uname collates before the name of the current entry, there
253                  * is definitely no such name in this index but we might need to
254                  * descend into the B+tree so we just break out of the loop.
255                  */
256                 if (rc == -1)
257                         break;
258                 /* The names are not equal, continue the search. */
259                 if (rc)
260                         continue;
261                 /*
262                  * Names match with case insensitive comparison, now try the
263                  * case sensitive comparison, which is required for proper
264                  * collation.
265                  */
266                 rc = ntfs_collate_names(uname, uname_len,
267                                 (ntfschar*)&ie->key.file_name.file_name,
268                                 ie->key.file_name.file_name_length, 1,
269                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len);
270                 if (rc == -1)
271                         break;
272                 if (rc)
273                         continue;
274                 /*
275                  * Perfect match, this will never happen as the
276                  * ntfs_are_names_equal() call will have gotten a match but we
277                  * still treat it correctly.
278                  */
279                 goto found_it;
280         }
281         /*
282          * We have finished with this index without success. Check for the
283          * presence of a child node and if not present return -ENOENT, unless
284          * we have got a matching name cached in name in which case return the
285          * mft reference associated with it.
286          */
287         if (!(ie->flags & INDEX_ENTRY_NODE)) {
288                 if (name) {
289                         ntfs_attr_put_search_ctx(ctx);
290                         unmap_mft_record(dir_ni);
291                         return name->mref;
292                 }
293                 ntfs_debug("Entry not found.");
294                 err = -ENOENT;
295                 goto err_out;
296         } /* Child node present, descend into it. */
297         /* Consistency check: Verify that an index allocation exists. */
298         if (!NInoIndexAllocPresent(dir_ni)) {
299                 ntfs_error(sb, "No index allocation attribute but index entry "
300                                 "requires one. Directory inode 0x%lx is "
301                                 "corrupt or driver bug.", dir_ni->mft_no);
302                 goto err_out;
303         }
304         /* Get the starting vcn of the index_block holding the child node. */
305         vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8));
306         ia_mapping = VFS_I(dir_ni)->i_mapping;
307         /*
308          * We are done with the index root and the mft record. Release them,
309          * otherwise we deadlock with ntfs_map_page().
310          */
311         ntfs_attr_put_search_ctx(ctx);
312         unmap_mft_record(dir_ni);
313         m = NULL;
314         ctx = NULL;
315 descend_into_child_node:
316         /*
317          * Convert vcn to index into the index allocation attribute in units
318          * of PAGE_SIZE and map the page cache page, reading it from
319          * disk if necessary.
320          */
321         page = ntfs_map_page(ia_mapping, vcn <<
322                         dir_ni->itype.index.vcn_size_bits >> PAGE_SHIFT);
323         if (IS_ERR(page)) {
324                 ntfs_error(sb, "Failed to map directory index page, error %ld.",
325                                 -PTR_ERR(page));
326                 err = PTR_ERR(page);
327                 goto err_out;
328         }
329         lock_page(page);
330         kaddr = (u8*)page_address(page);
331 fast_descend_into_child_node:
332         /* Get to the index allocation block. */
333         ia = (INDEX_ALLOCATION*)(kaddr + ((vcn <<
334                         dir_ni->itype.index.vcn_size_bits) & ~PAGE_MASK));
335         /* Bounds checks. */
336         if ((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_SIZE) {
337                 ntfs_error(sb, "Out of bounds check failed. Corrupt directory "
338                                 "inode 0x%lx or driver bug.", dir_ni->mft_no);
339                 goto unm_err_out;
340         }
341         /* Catch multi sector transfer fixup errors. */
342         if (unlikely(!ntfs_is_indx_record(ia->magic))) {
343                 ntfs_error(sb, "Directory index record with vcn 0x%llx is "
344                                 "corrupt.  Corrupt inode 0x%lx.  Run chkdsk.",
345                                 (unsigned long long)vcn, dir_ni->mft_no);
346                 goto unm_err_out;
347         }
348         if (sle64_to_cpu(ia->index_block_vcn) != vcn) {
349                 ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
350                                 "different from expected VCN (0x%llx). "
351                                 "Directory inode 0x%lx is corrupt or driver "
352                                 "bug.", (unsigned long long)
353                                 sle64_to_cpu(ia->index_block_vcn),
354                                 (unsigned long long)vcn, dir_ni->mft_no);
355                 goto unm_err_out;
356         }
357         if (le32_to_cpu(ia->index.allocated_size) + 0x18 !=
358                         dir_ni->itype.index.block_size) {
359                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
360                                 "0x%lx has a size (%u) differing from the "
361                                 "directory specified size (%u). Directory "
362                                 "inode is corrupt or driver bug.",
363                                 (unsigned long long)vcn, dir_ni->mft_no,
364                                 le32_to_cpu(ia->index.allocated_size) + 0x18,
365                                 dir_ni->itype.index.block_size);
366                 goto unm_err_out;
367         }
368         index_end = (u8*)ia + dir_ni->itype.index.block_size;
369         if (index_end > kaddr + PAGE_SIZE) {
370                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
371                                 "0x%lx crosses page boundary. Impossible! "
372                                 "Cannot access! This is probably a bug in the "
373                                 "driver.", (unsigned long long)vcn,
374                                 dir_ni->mft_no);
375                 goto unm_err_out;
376         }
377         index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
378         if (index_end > (u8*)ia + dir_ni->itype.index.block_size) {
379                 ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of directory "
380                                 "inode 0x%lx exceeds maximum size.",
381                                 (unsigned long long)vcn, dir_ni->mft_no);
382                 goto unm_err_out;
383         }
384         /* The first index entry. */
385         ie = (INDEX_ENTRY*)((u8*)&ia->index +
386                         le32_to_cpu(ia->index.entries_offset));
387         /*
388          * Iterate similar to above big loop but applied to index buffer, thus
389          * loop until we exceed valid memory (corruption case) or until we
390          * reach the last entry.
391          */
392         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
393                 /* Bounds check. */
394                 if ((u8*)ie < (u8*)ia || (u8*)ie +
395                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
396                                 (u8*)ie + le16_to_cpu(ie->key_length) >
397                                 index_end) {
398                         ntfs_error(sb, "Index entry out of bounds in "
399                                         "directory inode 0x%lx.",
400                                         dir_ni->mft_no);
401                         goto unm_err_out;
402                 }
403                 /*
404                  * The last entry cannot contain a name. It can however contain
405                  * a pointer to a child node in the B+tree so we just break out.
406                  */
407                 if (ie->flags & INDEX_ENTRY_END)
408                         break;
409                 /*
410                  * We perform a case sensitive comparison and if that matches
411                  * we are done and return the mft reference of the inode (i.e.
412                  * the inode number together with the sequence number for
413                  * consistency checking). We convert it to cpu format before
414                  * returning.
415                  */
416                 if (ntfs_are_names_equal(uname, uname_len,
417                                 (ntfschar*)&ie->key.file_name.file_name,
418                                 ie->key.file_name.file_name_length,
419                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len)) {
420 found_it2:
421                         /*
422                          * We have a perfect match, so we don't need to care
423                          * about having matched imperfectly before, so we can
424                          * free name and set *res to NULL.
425                          * However, if the perfect match is a short file name,
426                          * we need to signal this through *res, so that
427                          * ntfs_lookup() can fix dcache aliasing issues.
428                          * As an optimization we just reuse an existing
429                          * allocation of *res.
430                          */
431                         if (ie->key.file_name.file_name_type == FILE_NAME_DOS) {
432                                 if (!name) {
433                                         name = kmalloc(sizeof(ntfs_name),
434                                                         GFP_NOFS);
435                                         if (!name) {
436                                                 err = -ENOMEM;
437                                                 goto unm_err_out;
438                                         }
439                                 }
440                                 name->mref = le64_to_cpu(
441                                                 ie->data.dir.indexed_file);
442                                 name->type = FILE_NAME_DOS;
443                                 name->len = 0;
444                                 *res = name;
445                         } else {
446                                 kfree(name);
447                                 *res = NULL;
448                         }
449                         mref = le64_to_cpu(ie->data.dir.indexed_file);
450                         unlock_page(page);
451                         ntfs_unmap_page(page);
452                         return mref;
453                 }
454                 /*
455                  * For a case insensitive mount, we also perform a case
456                  * insensitive comparison (provided the file name is not in the
457                  * POSIX namespace). If the comparison matches, and the name is
458                  * in the WIN32 namespace, we cache the filename in *res so
459                  * that the caller, ntfs_lookup(), can work on it. If the
460                  * comparison matches, and the name is in the DOS namespace, we
461                  * only cache the mft reference and the file name type (we set
462                  * the name length to zero for simplicity).
463                  */
464                 if (!NVolCaseSensitive(vol) &&
465                                 ie->key.file_name.file_name_type &&
466                                 ntfs_are_names_equal(uname, uname_len,
467                                 (ntfschar*)&ie->key.file_name.file_name,
468                                 ie->key.file_name.file_name_length,
469                                 IGNORE_CASE, vol->upcase, vol->upcase_len)) {
470                         int name_size = sizeof(ntfs_name);
471                         u8 type = ie->key.file_name.file_name_type;
472                         u8 len = ie->key.file_name.file_name_length;
473 
474                         /* Only one case insensitive matching name allowed. */
475                         if (name) {
476                                 ntfs_error(sb, "Found already allocated name "
477                                                 "in phase 2. Please run chkdsk "
478                                                 "and if that doesn't find any "
479                                                 "errors please report you saw "
480                                                 "this message to "
481                                                 "linux-ntfs-dev@lists."
482                                                 "sourceforge.net.");
483                                 unlock_page(page);
484                                 ntfs_unmap_page(page);
485                                 goto dir_err_out;
486                         }
487 
488                         if (type != FILE_NAME_DOS)
489                                 name_size += len * sizeof(ntfschar);
490                         name = kmalloc(name_size, GFP_NOFS);
491                         if (!name) {
492                                 err = -ENOMEM;
493                                 goto unm_err_out;
494                         }
495                         name->mref = le64_to_cpu(ie->data.dir.indexed_file);
496                         name->type = type;
497                         if (type != FILE_NAME_DOS) {
498                                 name->len = len;
499                                 memcpy(name->name, ie->key.file_name.file_name,
500                                                 len * sizeof(ntfschar));
501                         } else
502                                 name->len = 0;
503                         *res = name;
504                 }
505                 /*
506                  * Not a perfect match, need to do full blown collation so we
507                  * know which way in the B+tree we have to go.
508                  */
509                 rc = ntfs_collate_names(uname, uname_len,
510                                 (ntfschar*)&ie->key.file_name.file_name,
511                                 ie->key.file_name.file_name_length, 1,
512                                 IGNORE_CASE, vol->upcase, vol->upcase_len);
513                 /*
514                  * If uname collates before the name of the current entry, there
515                  * is definitely no such name in this index but we might need to
516                  * descend into the B+tree so we just break out of the loop.
517                  */
518                 if (rc == -1)
519                         break;
520                 /* The names are not equal, continue the search. */
521                 if (rc)
522                         continue;
523                 /*
524                  * Names match with case insensitive comparison, now try the
525                  * case sensitive comparison, which is required for proper
526                  * collation.
527                  */
528                 rc = ntfs_collate_names(uname, uname_len,
529                                 (ntfschar*)&ie->key.file_name.file_name,
530                                 ie->key.file_name.file_name_length, 1,
531                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len);
532                 if (rc == -1)
533                         break;
534                 if (rc)
535                         continue;
536                 /*
537                  * Perfect match, this will never happen as the
538                  * ntfs_are_names_equal() call will have gotten a match but we
539                  * still treat it correctly.
540                  */
541                 goto found_it2;
542         }
543         /*
544          * We have finished with this index buffer without success. Check for
545          * the presence of a child node.
546          */
547         if (ie->flags & INDEX_ENTRY_NODE) {
548                 if ((ia->index.flags & NODE_MASK) == LEAF_NODE) {
549                         ntfs_error(sb, "Index entry with child node found in "
550                                         "a leaf node in directory inode 0x%lx.",
551                                         dir_ni->mft_no);
552                         goto unm_err_out;
553                 }
554                 /* Child node present, descend into it. */
555                 old_vcn = vcn;
556                 vcn = sle64_to_cpup((sle64*)((u8*)ie +
557                                 le16_to_cpu(ie->length) - 8));
558                 if (vcn >= 0) {
559                         /* If vcn is in the same page cache page as old_vcn we
560                          * recycle the mapped page. */
561                         if (old_vcn << vol->cluster_size_bits >>
562                                         PAGE_SHIFT == vcn <<
563                                         vol->cluster_size_bits >>
564                                         PAGE_SHIFT)
565                                 goto fast_descend_into_child_node;
566                         unlock_page(page);
567                         ntfs_unmap_page(page);
568                         goto descend_into_child_node;
569                 }
570                 ntfs_error(sb, "Negative child node vcn in directory inode "
571                                 "0x%lx.", dir_ni->mft_no);
572                 goto unm_err_out;
573         }
574         /*
575          * No child node present, return -ENOENT, unless we have got a matching
576          * name cached in name in which case return the mft reference
577          * associated with it.
578          */
579         if (name) {
580                 unlock_page(page);
581                 ntfs_unmap_page(page);
582                 return name->mref;
583         }
584         ntfs_debug("Entry not found.");
585         err = -ENOENT;
586 unm_err_out:
587         unlock_page(page);
588         ntfs_unmap_page(page);
589 err_out:
590         if (!err)
591                 err = -EIO;
592         if (ctx)
593                 ntfs_attr_put_search_ctx(ctx);
594         if (m)
595                 unmap_mft_record(dir_ni);
596         if (name) {
597                 kfree(name);
598                 *res = NULL;
599         }
600         return ERR_MREF(err);
601 dir_err_out:
602         ntfs_error(sb, "Corrupt directory.  Aborting lookup.");
603         goto err_out;
604 }
605 
606 #if 0
607 
608 // TODO: (AIA)
609 // The algorithm embedded in this code will be required for the time when we
610 // want to support adding of entries to directories, where we require correct
611 // collation of file names in order not to cause corruption of the filesystem.
612 
613 /**
614  * ntfs_lookup_inode_by_name - find an inode in a directory given its name
615  * @dir_ni:     ntfs inode of the directory in which to search for the name
616  * @uname:      Unicode name for which to search in the directory
617  * @uname_len:  length of the name @uname in Unicode characters
618  *
619  * Look for an inode with name @uname in the directory with inode @dir_ni.
620  * ntfs_lookup_inode_by_name() walks the contents of the directory looking for
621  * the Unicode name. If the name is found in the directory, the corresponding
622  * inode number (>= 0) is returned as a mft reference in cpu format, i.e. it
623  * is a 64-bit number containing the sequence number.
624  *
625  * On error, a negative value is returned corresponding to the error code. In
626  * particular if the inode is not found -ENOENT is returned. Note that you
627  * can't just check the return value for being negative, you have to check the
628  * inode number for being negative which you can extract using MREC(return
629  * value).
630  *
631  * Note, @uname_len does not include the (optional) terminating NULL character.
632  */
633 u64 ntfs_lookup_inode_by_name(ntfs_inode *dir_ni, const ntfschar *uname,
634                 const int uname_len)
635 {
636         ntfs_volume *vol = dir_ni->vol;
637         struct super_block *sb = vol->sb;
638         MFT_RECORD *m;
639         INDEX_ROOT *ir;
640         INDEX_ENTRY *ie;
641         INDEX_ALLOCATION *ia;
642         u8 *index_end;
643         u64 mref;
644         ntfs_attr_search_ctx *ctx;
645         int err, rc;
646         IGNORE_CASE_BOOL ic;
647         VCN vcn, old_vcn;
648         struct address_space *ia_mapping;
649         struct page *page;
650         u8 *kaddr;
651 
652         /* Get hold of the mft record for the directory. */
653         m = map_mft_record(dir_ni);
654         if (IS_ERR(m)) {
655                 ntfs_error(sb, "map_mft_record() failed with error code %ld.",
656                                 -PTR_ERR(m));
657                 return ERR_MREF(PTR_ERR(m));
658         }
659         ctx = ntfs_attr_get_search_ctx(dir_ni, m);
660         if (!ctx) {
661                 err = -ENOMEM;
662                 goto err_out;
663         }
664         /* Find the index root attribute in the mft record. */
665         err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE, 0, NULL,
666                         0, ctx);
667         if (unlikely(err)) {
668                 if (err == -ENOENT) {
669                         ntfs_error(sb, "Index root attribute missing in "
670                                         "directory inode 0x%lx.",
671                                         dir_ni->mft_no);
672                         err = -EIO;
673                 }
674                 goto err_out;
675         }
676         /* Get to the index root value (it's been verified in read_inode). */
677         ir = (INDEX_ROOT*)((u8*)ctx->attr +
678                         le16_to_cpu(ctx->attr->data.resident.value_offset));
679         index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
680         /* The first index entry. */
681         ie = (INDEX_ENTRY*)((u8*)&ir->index +
682                         le32_to_cpu(ir->index.entries_offset));
683         /*
684          * Loop until we exceed valid memory (corruption case) or until we
685          * reach the last entry.
686          */
687         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
688                 /* Bounds checks. */
689                 if ((u8*)ie < (u8*)ctx->mrec || (u8*)ie +
690                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
691                                 (u8*)ie + le16_to_cpu(ie->key_length) >
692                                 index_end)
693                         goto dir_err_out;
694                 /*
695                  * The last entry cannot contain a name. It can however contain
696                  * a pointer to a child node in the B+tree so we just break out.
697                  */
698                 if (ie->flags & INDEX_ENTRY_END)
699                         break;
700                 /*
701                  * If the current entry has a name type of POSIX, the name is
702                  * case sensitive and not otherwise. This has the effect of us
703                  * not being able to access any POSIX file names which collate
704                  * after the non-POSIX one when they only differ in case, but
705                  * anyone doing screwy stuff like that deserves to burn in
706                  * hell... Doing that kind of stuff on NT4 actually causes
707                  * corruption on the partition even when using SP6a and Linux
708                  * is not involved at all.
709                  */
710                 ic = ie->key.file_name.file_name_type ? IGNORE_CASE :
711                                 CASE_SENSITIVE;
712                 /*
713                  * If the names match perfectly, we are done and return the
714                  * mft reference of the inode (i.e. the inode number together
715                  * with the sequence number for consistency checking. We
716                  * convert it to cpu format before returning.
717                  */
718                 if (ntfs_are_names_equal(uname, uname_len,
719                                 (ntfschar*)&ie->key.file_name.file_name,
720                                 ie->key.file_name.file_name_length, ic,
721                                 vol->upcase, vol->upcase_len)) {
722 found_it:
723                         mref = le64_to_cpu(ie->data.dir.indexed_file);
724                         ntfs_attr_put_search_ctx(ctx);
725                         unmap_mft_record(dir_ni);
726                         return mref;
727                 }
728                 /*
729                  * Not a perfect match, need to do full blown collation so we
730                  * know which way in the B+tree we have to go.
731                  */
732                 rc = ntfs_collate_names(uname, uname_len,
733                                 (ntfschar*)&ie->key.file_name.file_name,
734                                 ie->key.file_name.file_name_length, 1,
735                                 IGNORE_CASE, vol->upcase, vol->upcase_len);
736                 /*
737                  * If uname collates before the name of the current entry, there
738                  * is definitely no such name in this index but we might need to
739                  * descend into the B+tree so we just break out of the loop.
740                  */
741                 if (rc == -1)
742                         break;
743                 /* The names are not equal, continue the search. */
744                 if (rc)
745                         continue;
746                 /*
747                  * Names match with case insensitive comparison, now try the
748                  * case sensitive comparison, which is required for proper
749                  * collation.
750                  */
751                 rc = ntfs_collate_names(uname, uname_len,
752                                 (ntfschar*)&ie->key.file_name.file_name,
753                                 ie->key.file_name.file_name_length, 1,
754                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len);
755                 if (rc == -1)
756                         break;
757                 if (rc)
758                         continue;
759                 /*
760                  * Perfect match, this will never happen as the
761                  * ntfs_are_names_equal() call will have gotten a match but we
762                  * still treat it correctly.
763                  */
764                 goto found_it;
765         }
766         /*
767          * We have finished with this index without success. Check for the
768          * presence of a child node.
769          */
770         if (!(ie->flags & INDEX_ENTRY_NODE)) {
771                 /* No child node, return -ENOENT. */
772                 err = -ENOENT;
773                 goto err_out;
774         } /* Child node present, descend into it. */
775         /* Consistency check: Verify that an index allocation exists. */
776         if (!NInoIndexAllocPresent(dir_ni)) {
777                 ntfs_error(sb, "No index allocation attribute but index entry "
778                                 "requires one. Directory inode 0x%lx is "
779                                 "corrupt or driver bug.", dir_ni->mft_no);
780                 goto err_out;
781         }
782         /* Get the starting vcn of the index_block holding the child node. */
783         vcn = sle64_to_cpup((u8*)ie + le16_to_cpu(ie->length) - 8);
784         ia_mapping = VFS_I(dir_ni)->i_mapping;
785         /*
786          * We are done with the index root and the mft record. Release them,
787          * otherwise we deadlock with ntfs_map_page().
788          */
789         ntfs_attr_put_search_ctx(ctx);
790         unmap_mft_record(dir_ni);
791         m = NULL;
792         ctx = NULL;
793 descend_into_child_node:
794         /*
795          * Convert vcn to index into the index allocation attribute in units
796          * of PAGE_SIZE and map the page cache page, reading it from
797          * disk if necessary.
798          */
799         page = ntfs_map_page(ia_mapping, vcn <<
800                         dir_ni->itype.index.vcn_size_bits >> PAGE_SHIFT);
801         if (IS_ERR(page)) {
802                 ntfs_error(sb, "Failed to map directory index page, error %ld.",
803                                 -PTR_ERR(page));
804                 err = PTR_ERR(page);
805                 goto err_out;
806         }
807         lock_page(page);
808         kaddr = (u8*)page_address(page);
809 fast_descend_into_child_node:
810         /* Get to the index allocation block. */
811         ia = (INDEX_ALLOCATION*)(kaddr + ((vcn <<
812                         dir_ni->itype.index.vcn_size_bits) & ~PAGE_MASK));
813         /* Bounds checks. */
814         if ((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_SIZE) {
815                 ntfs_error(sb, "Out of bounds check failed. Corrupt directory "
816                                 "inode 0x%lx or driver bug.", dir_ni->mft_no);
817                 goto unm_err_out;
818         }
819         /* Catch multi sector transfer fixup errors. */
820         if (unlikely(!ntfs_is_indx_record(ia->magic))) {
821                 ntfs_error(sb, "Directory index record with vcn 0x%llx is "
822                                 "corrupt.  Corrupt inode 0x%lx.  Run chkdsk.",
823                                 (unsigned long long)vcn, dir_ni->mft_no);
824                 goto unm_err_out;
825         }
826         if (sle64_to_cpu(ia->index_block_vcn) != vcn) {
827                 ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
828                                 "different from expected VCN (0x%llx). "
829                                 "Directory inode 0x%lx is corrupt or driver "
830                                 "bug.", (unsigned long long)
831                                 sle64_to_cpu(ia->index_block_vcn),
832                                 (unsigned long long)vcn, dir_ni->mft_no);
833                 goto unm_err_out;
834         }
835         if (le32_to_cpu(ia->index.allocated_size) + 0x18 !=
836                         dir_ni->itype.index.block_size) {
837                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
838                                 "0x%lx has a size (%u) differing from the "
839                                 "directory specified size (%u). Directory "
840                                 "inode is corrupt or driver bug.",
841                                 (unsigned long long)vcn, dir_ni->mft_no,
842                                 le32_to_cpu(ia->index.allocated_size) + 0x18,
843                                 dir_ni->itype.index.block_size);
844                 goto unm_err_out;
845         }
846         index_end = (u8*)ia + dir_ni->itype.index.block_size;
847         if (index_end > kaddr + PAGE_SIZE) {
848                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
849                                 "0x%lx crosses page boundary. Impossible! "
850                                 "Cannot access! This is probably a bug in the "
851                                 "driver.", (unsigned long long)vcn,
852                                 dir_ni->mft_no);
853                 goto unm_err_out;
854         }
855         index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
856         if (index_end > (u8*)ia + dir_ni->itype.index.block_size) {
857                 ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of directory "
858                                 "inode 0x%lx exceeds maximum size.",
859                                 (unsigned long long)vcn, dir_ni->mft_no);
860                 goto unm_err_out;
861         }
862         /* The first index entry. */
863         ie = (INDEX_ENTRY*)((u8*)&ia->index +
864                         le32_to_cpu(ia->index.entries_offset));
865         /*
866          * Iterate similar to above big loop but applied to index buffer, thus
867          * loop until we exceed valid memory (corruption case) or until we
868          * reach the last entry.
869          */
870         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
871                 /* Bounds check. */
872                 if ((u8*)ie < (u8*)ia || (u8*)ie +
873                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
874                                 (u8*)ie + le16_to_cpu(ie->key_length) >
875                                 index_end) {
876                         ntfs_error(sb, "Index entry out of bounds in "
877                                         "directory inode 0x%lx.",
878                                         dir_ni->mft_no);
879                         goto unm_err_out;
880                 }
881                 /*
882                  * The last entry cannot contain a name. It can however contain
883                  * a pointer to a child node in the B+tree so we just break out.
884                  */
885                 if (ie->flags & INDEX_ENTRY_END)
886                         break;
887                 /*
888                  * If the current entry has a name type of POSIX, the name is
889                  * case sensitive and not otherwise. This has the effect of us
890                  * not being able to access any POSIX file names which collate
891                  * after the non-POSIX one when they only differ in case, but
892                  * anyone doing screwy stuff like that deserves to burn in
893                  * hell... Doing that kind of stuff on NT4 actually causes
894                  * corruption on the partition even when using SP6a and Linux
895                  * is not involved at all.
896                  */
897                 ic = ie->key.file_name.file_name_type ? IGNORE_CASE :
898                                 CASE_SENSITIVE;
899                 /*
900                  * If the names match perfectly, we are done and return the
901                  * mft reference of the inode (i.e. the inode number together
902                  * with the sequence number for consistency checking. We
903                  * convert it to cpu format before returning.
904                  */
905                 if (ntfs_are_names_equal(uname, uname_len,
906                                 (ntfschar*)&ie->key.file_name.file_name,
907                                 ie->key.file_name.file_name_length, ic,
908                                 vol->upcase, vol->upcase_len)) {
909 found_it2:
910                         mref = le64_to_cpu(ie->data.dir.indexed_file);
911                         unlock_page(page);
912                         ntfs_unmap_page(page);
913                         return mref;
914                 }
915                 /*
916                  * Not a perfect match, need to do full blown collation so we
917                  * know which way in the B+tree we have to go.
918                  */
919                 rc = ntfs_collate_names(uname, uname_len,
920                                 (ntfschar*)&ie->key.file_name.file_name,
921                                 ie->key.file_name.file_name_length, 1,
922                                 IGNORE_CASE, vol->upcase, vol->upcase_len);
923                 /*
924                  * If uname collates before the name of the current entry, there
925                  * is definitely no such name in this index but we might need to
926                  * descend into the B+tree so we just break out of the loop.
927                  */
928                 if (rc == -1)
929                         break;
930                 /* The names are not equal, continue the search. */
931                 if (rc)
932                         continue;
933                 /*
934                  * Names match with case insensitive comparison, now try the
935                  * case sensitive comparison, which is required for proper
936                  * collation.
937                  */
938                 rc = ntfs_collate_names(uname, uname_len,
939                                 (ntfschar*)&ie->key.file_name.file_name,
940                                 ie->key.file_name.file_name_length, 1,
941                                 CASE_SENSITIVE, vol->upcase, vol->upcase_len);
942                 if (rc == -1)
943                         break;
944                 if (rc)
945                         continue;
946                 /*
947                  * Perfect match, this will never happen as the
948                  * ntfs_are_names_equal() call will have gotten a match but we
949                  * still treat it correctly.
950                  */
951                 goto found_it2;
952         }
953         /*
954          * We have finished with this index buffer without success. Check for
955          * the presence of a child node.
956          */
957         if (ie->flags & INDEX_ENTRY_NODE) {
958                 if ((ia->index.flags & NODE_MASK) == LEAF_NODE) {
959                         ntfs_error(sb, "Index entry with child node found in "
960                                         "a leaf node in directory inode 0x%lx.",
961                                         dir_ni->mft_no);
962                         goto unm_err_out;
963                 }
964                 /* Child node present, descend into it. */
965                 old_vcn = vcn;
966                 vcn = sle64_to_cpup((u8*)ie + le16_to_cpu(ie->length) - 8);
967                 if (vcn >= 0) {
968                         /* If vcn is in the same page cache page as old_vcn we
969                          * recycle the mapped page. */
970                         if (old_vcn << vol->cluster_size_bits >>
971                                         PAGE_SHIFT == vcn <<
972                                         vol->cluster_size_bits >>
973                                         PAGE_SHIFT)
974                                 goto fast_descend_into_child_node;
975                         unlock_page(page);
976                         ntfs_unmap_page(page);
977                         goto descend_into_child_node;
978                 }
979                 ntfs_error(sb, "Negative child node vcn in directory inode "
980                                 "0x%lx.", dir_ni->mft_no);
981                 goto unm_err_out;
982         }
983         /* No child node, return -ENOENT. */
984         ntfs_debug("Entry not found.");
985         err = -ENOENT;
986 unm_err_out:
987         unlock_page(page);
988         ntfs_unmap_page(page);
989 err_out:
990         if (!err)
991                 err = -EIO;
992         if (ctx)
993                 ntfs_attr_put_search_ctx(ctx);
994         if (m)
995                 unmap_mft_record(dir_ni);
996         return ERR_MREF(err);
997 dir_err_out:
998         ntfs_error(sb, "Corrupt directory. Aborting lookup.");
999         goto err_out;
1000 }
1001 
1002 #endif
1003 
1004 /**
1005  * ntfs_filldir - ntfs specific filldir method
1006  * @vol:        current ntfs volume
1007  * @ndir:       ntfs inode of current directory
1008  * @ia_page:    page in which the index allocation buffer @ie is in resides
1009  * @ie:         current index entry
1010  * @name:       buffer to use for the converted name
1011  * @actor:      what to feed the entries to
1012  *
1013  * Convert the Unicode @name to the loaded NLS and pass it to the @filldir
1014  * callback.
1015  *
1016  * If @ia_page is not NULL it is the locked page containing the index
1017  * allocation block containing the index entry @ie.
1018  *
1019  * Note, we drop (and then reacquire) the page lock on @ia_page across the
1020  * @filldir() call otherwise we would deadlock with NFSd when it calls ->lookup
1021  * since ntfs_lookup() will lock the same page.  As an optimization, we do not
1022  * retake the lock if we are returning a non-zero value as ntfs_readdir()
1023  * would need to drop the lock immediately anyway.
1024  */
1025 static inline int ntfs_filldir(ntfs_volume *vol,
1026                 ntfs_inode *ndir, struct page *ia_page, INDEX_ENTRY *ie,
1027                 u8 *name, struct dir_context *actor)
1028 {
1029         unsigned long mref;
1030         int name_len;
1031         unsigned dt_type;
1032         FILE_NAME_TYPE_FLAGS name_type;
1033 
1034         name_type = ie->key.file_name.file_name_type;
1035         if (name_type == FILE_NAME_DOS) {
1036                 ntfs_debug("Skipping DOS name space entry.");
1037                 return 0;
1038         }
1039         if (MREF_LE(ie->data.dir.indexed_file) == FILE_root) {
1040                 ntfs_debug("Skipping root directory self reference entry.");
1041                 return 0;
1042         }
1043         if (MREF_LE(ie->data.dir.indexed_file) < FILE_first_user &&
1044                         !NVolShowSystemFiles(vol)) {
1045                 ntfs_debug("Skipping system file.");
1046                 return 0;
1047         }
1048         name_len = ntfs_ucstonls(vol, (ntfschar*)&ie->key.file_name.file_name,
1049                         ie->key.file_name.file_name_length, &name,
1050                         NTFS_MAX_NAME_LEN * NLS_MAX_CHARSET_SIZE + 1);
1051         if (name_len <= 0) {
1052                 ntfs_warning(vol->sb, "Skipping unrepresentable inode 0x%llx.",
1053                                 (long long)MREF_LE(ie->data.dir.indexed_file));
1054                 return 0;
1055         }
1056         if (ie->key.file_name.file_attributes &
1057                         FILE_ATTR_DUP_FILE_NAME_INDEX_PRESENT)
1058                 dt_type = DT_DIR;
1059         else
1060                 dt_type = DT_REG;
1061         mref = MREF_LE(ie->data.dir.indexed_file);
1062         /*
1063          * Drop the page lock otherwise we deadlock with NFS when it calls
1064          * ->lookup since ntfs_lookup() will lock the same page.
1065          */
1066         if (ia_page)
1067                 unlock_page(ia_page);
1068         ntfs_debug("Calling filldir for %s with len %i, fpos 0x%llx, inode "
1069                         "0x%lx, DT_%s.", name, name_len, actor->pos, mref,
1070                         dt_type == DT_DIR ? "DIR" : "REG");
1071         if (!dir_emit(actor, name, name_len, mref, dt_type))
1072                 return 1;
1073         /* Relock the page but not if we are aborting ->readdir. */
1074         if (ia_page)
1075                 lock_page(ia_page);
1076         return 0;
1077 }
1078 
1079 /*
1080  * We use the same basic approach as the old NTFS driver, i.e. we parse the
1081  * index root entries and then the index allocation entries that are marked
1082  * as in use in the index bitmap.
1083  *
1084  * While this will return the names in random order this doesn't matter for
1085  * ->readdir but OTOH results in a faster ->readdir.
1086  *
1087  * VFS calls ->readdir without BKL but with i_mutex held. This protects the VFS
1088  * parts (e.g. ->f_pos and ->i_size, and it also protects against directory
1089  * modifications).
1090  *
1091  * Locking:  - Caller must hold i_mutex on the directory.
1092  *           - Each page cache page in the index allocation mapping must be
1093  *             locked whilst being accessed otherwise we may find a corrupt
1094  *             page due to it being under ->writepage at the moment which
1095  *             applies the mst protection fixups before writing out and then
1096  *             removes them again after the write is complete after which it 
1097  *             unlocks the page.
1098  */
1099 static int ntfs_readdir(struct file *file, struct dir_context *actor)
1100 {
1101         s64 ia_pos, ia_start, prev_ia_pos, bmp_pos;
1102         loff_t i_size;
1103         struct inode *bmp_vi, *vdir = file_inode(file);
1104         struct super_block *sb = vdir->i_sb;
1105         ntfs_inode *ndir = NTFS_I(vdir);
1106         ntfs_volume *vol = NTFS_SB(sb);
1107         MFT_RECORD *m;
1108         INDEX_ROOT *ir = NULL;
1109         INDEX_ENTRY *ie;
1110         INDEX_ALLOCATION *ia;
1111         u8 *name = NULL;
1112         int rc, err, ir_pos, cur_bmp_pos;
1113         struct address_space *ia_mapping, *bmp_mapping;
1114         struct page *bmp_page = NULL, *ia_page = NULL;
1115         u8 *kaddr, *bmp, *index_end;
1116         ntfs_attr_search_ctx *ctx;
1117 
1118         ntfs_debug("Entering for inode 0x%lx, fpos 0x%llx.",
1119                         vdir->i_ino, actor->pos);
1120         rc = err = 0;
1121         /* Are we at end of dir yet? */
1122         i_size = i_size_read(vdir);
1123         if (actor->pos >= i_size + vol->mft_record_size)
1124                 return 0;
1125         /* Emulate . and .. for all directories. */
1126         if (!dir_emit_dots(file, actor))
1127                 return 0;
1128         m = NULL;
1129         ctx = NULL;
1130         /*
1131          * Allocate a buffer to store the current name being processed
1132          * converted to format determined by current NLS.
1133          */
1134         name = kmalloc(NTFS_MAX_NAME_LEN * NLS_MAX_CHARSET_SIZE + 1, GFP_NOFS);
1135         if (unlikely(!name)) {
1136                 err = -ENOMEM;
1137                 goto err_out;
1138         }
1139         /* Are we jumping straight into the index allocation attribute? */
1140         if (actor->pos >= vol->mft_record_size)
1141                 goto skip_index_root;
1142         /* Get hold of the mft record for the directory. */
1143         m = map_mft_record(ndir);
1144         if (IS_ERR(m)) {
1145                 err = PTR_ERR(m);
1146                 m = NULL;
1147                 goto err_out;
1148         }
1149         ctx = ntfs_attr_get_search_ctx(ndir, m);
1150         if (unlikely(!ctx)) {
1151                 err = -ENOMEM;
1152                 goto err_out;
1153         }
1154         /* Get the offset into the index root attribute. */
1155         ir_pos = (s64)actor->pos;
1156         /* Find the index root attribute in the mft record. */
1157         err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE, 0, NULL,
1158                         0, ctx);
1159         if (unlikely(err)) {
1160                 ntfs_error(sb, "Index root attribute missing in directory "
1161                                 "inode 0x%lx.", vdir->i_ino);
1162                 goto err_out;
1163         }
1164         /*
1165          * Copy the index root attribute value to a buffer so that we can put
1166          * the search context and unmap the mft record before calling the
1167          * filldir() callback.  We need to do this because of NFSd which calls
1168          * ->lookup() from its filldir callback() and this causes NTFS to
1169          * deadlock as ntfs_lookup() maps the mft record of the directory and
1170          * we have got it mapped here already.  The only solution is for us to
1171          * unmap the mft record here so that a call to ntfs_lookup() is able to
1172          * map the mft record without deadlocking.
1173          */
1174         rc = le32_to_cpu(ctx->attr->data.resident.value_length);
1175         ir = kmalloc(rc, GFP_NOFS);
1176         if (unlikely(!ir)) {
1177                 err = -ENOMEM;
1178                 goto err_out;
1179         }
1180         /* Copy the index root value (it has been verified in read_inode). */
1181         memcpy(ir, (u8*)ctx->attr +
1182                         le16_to_cpu(ctx->attr->data.resident.value_offset), rc);
1183         ntfs_attr_put_search_ctx(ctx);
1184         unmap_mft_record(ndir);
1185         ctx = NULL;
1186         m = NULL;
1187         index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
1188         /* The first index entry. */
1189         ie = (INDEX_ENTRY*)((u8*)&ir->index +
1190                         le32_to_cpu(ir->index.entries_offset));
1191         /*
1192          * Loop until we exceed valid memory (corruption case) or until we
1193          * reach the last entry or until filldir tells us it has had enough
1194          * or signals an error (both covered by the rc test).
1195          */
1196         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
1197                 ntfs_debug("In index root, offset 0x%zx.", (u8*)ie - (u8*)ir);
1198                 /* Bounds checks. */
1199                 if (unlikely((u8*)ie < (u8*)ir || (u8*)ie +
1200                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
1201                                 (u8*)ie + le16_to_cpu(ie->key_length) >
1202                                 index_end))
1203                         goto err_out;
1204                 /* The last entry cannot contain a name. */
1205                 if (ie->flags & INDEX_ENTRY_END)
1206                         break;
1207                 /* Skip index root entry if continuing previous readdir. */
1208                 if (ir_pos > (u8*)ie - (u8*)ir)
1209                         continue;
1210                 /* Advance the position even if going to skip the entry. */
1211                 actor->pos = (u8*)ie - (u8*)ir;
1212                 /* Submit the name to the filldir callback. */
1213                 rc = ntfs_filldir(vol, ndir, NULL, ie, name, actor);
1214                 if (rc) {
1215                         kfree(ir);
1216                         goto abort;
1217                 }
1218         }
1219         /* We are done with the index root and can free the buffer. */
1220         kfree(ir);
1221         ir = NULL;
1222         /* If there is no index allocation attribute we are finished. */
1223         if (!NInoIndexAllocPresent(ndir))
1224                 goto EOD;
1225         /* Advance fpos to the beginning of the index allocation. */
1226         actor->pos = vol->mft_record_size;
1227 skip_index_root:
1228         kaddr = NULL;
1229         prev_ia_pos = -1LL;
1230         /* Get the offset into the index allocation attribute. */
1231         ia_pos = (s64)actor->pos - vol->mft_record_size;
1232         ia_mapping = vdir->i_mapping;
1233         ntfs_debug("Inode 0x%lx, getting index bitmap.", vdir->i_ino);
1234         bmp_vi = ntfs_attr_iget(vdir, AT_BITMAP, I30, 4);
1235         if (IS_ERR(bmp_vi)) {
1236                 ntfs_error(sb, "Failed to get bitmap attribute.");
1237                 err = PTR_ERR(bmp_vi);
1238                 goto err_out;
1239         }
1240         bmp_mapping = bmp_vi->i_mapping;
1241         /* Get the starting bitmap bit position and sanity check it. */
1242         bmp_pos = ia_pos >> ndir->itype.index.block_size_bits;
1243         if (unlikely(bmp_pos >> 3 >= i_size_read(bmp_vi))) {
1244                 ntfs_error(sb, "Current index allocation position exceeds "
1245                                 "index bitmap size.");
1246                 goto iput_err_out;
1247         }
1248         /* Get the starting bit position in the current bitmap page. */
1249         cur_bmp_pos = bmp_pos & ((PAGE_SIZE * 8) - 1);
1250         bmp_pos &= ~(u64)((PAGE_SIZE * 8) - 1);
1251 get_next_bmp_page:
1252         ntfs_debug("Reading bitmap with page index 0x%llx, bit ofs 0x%llx",
1253                         (unsigned long long)bmp_pos >> (3 + PAGE_SHIFT),
1254                         (unsigned long long)bmp_pos &
1255                         (unsigned long long)((PAGE_SIZE * 8) - 1));
1256         bmp_page = ntfs_map_page(bmp_mapping,
1257                         bmp_pos >> (3 + PAGE_SHIFT));
1258         if (IS_ERR(bmp_page)) {
1259                 ntfs_error(sb, "Reading index bitmap failed.");
1260                 err = PTR_ERR(bmp_page);
1261                 bmp_page = NULL;
1262                 goto iput_err_out;
1263         }
1264         bmp = (u8*)page_address(bmp_page);
1265         /* Find next index block in use. */
1266         while (!(bmp[cur_bmp_pos >> 3] & (1 << (cur_bmp_pos & 7)))) {
1267 find_next_index_buffer:
1268                 cur_bmp_pos++;
1269                 /*
1270                  * If we have reached the end of the bitmap page, get the next
1271                  * page, and put away the old one.
1272                  */
1273                 if (unlikely((cur_bmp_pos >> 3) >= PAGE_SIZE)) {
1274                         ntfs_unmap_page(bmp_page);
1275                         bmp_pos += PAGE_SIZE * 8;
1276                         cur_bmp_pos = 0;
1277                         goto get_next_bmp_page;
1278                 }
1279                 /* If we have reached the end of the bitmap, we are done. */
1280                 if (unlikely(((bmp_pos + cur_bmp_pos) >> 3) >= i_size))
1281                         goto unm_EOD;
1282                 ia_pos = (bmp_pos + cur_bmp_pos) <<
1283                                 ndir->itype.index.block_size_bits;
1284         }
1285         ntfs_debug("Handling index buffer 0x%llx.",
1286                         (unsigned long long)bmp_pos + cur_bmp_pos);
1287         /* If the current index buffer is in the same page we reuse the page. */
1288         if ((prev_ia_pos & (s64)PAGE_MASK) !=
1289                         (ia_pos & (s64)PAGE_MASK)) {
1290                 prev_ia_pos = ia_pos;
1291                 if (likely(ia_page != NULL)) {
1292                         unlock_page(ia_page);
1293                         ntfs_unmap_page(ia_page);
1294                 }
1295                 /*
1296                  * Map the page cache page containing the current ia_pos,
1297                  * reading it from disk if necessary.
1298                  */
1299                 ia_page = ntfs_map_page(ia_mapping, ia_pos >> PAGE_SHIFT);
1300                 if (IS_ERR(ia_page)) {
1301                         ntfs_error(sb, "Reading index allocation data failed.");
1302                         err = PTR_ERR(ia_page);
1303                         ia_page = NULL;
1304                         goto err_out;
1305                 }
1306                 lock_page(ia_page);
1307                 kaddr = (u8*)page_address(ia_page);
1308         }
1309         /* Get the current index buffer. */
1310         ia = (INDEX_ALLOCATION*)(kaddr + (ia_pos & ~PAGE_MASK &
1311                                           ~(s64)(ndir->itype.index.block_size - 1)));
1312         /* Bounds checks. */
1313         if (unlikely((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_SIZE)) {
1314                 ntfs_error(sb, "Out of bounds check failed. Corrupt directory "
1315                                 "inode 0x%lx or driver bug.", vdir->i_ino);
1316                 goto err_out;
1317         }
1318         /* Catch multi sector transfer fixup errors. */
1319         if (unlikely(!ntfs_is_indx_record(ia->magic))) {
1320                 ntfs_error(sb, "Directory index record with vcn 0x%llx is "
1321                                 "corrupt.  Corrupt inode 0x%lx.  Run chkdsk.",
1322                                 (unsigned long long)ia_pos >>
1323                                 ndir->itype.index.vcn_size_bits, vdir->i_ino);
1324                 goto err_out;
1325         }
1326         if (unlikely(sle64_to_cpu(ia->index_block_vcn) != (ia_pos &
1327                         ~(s64)(ndir->itype.index.block_size - 1)) >>
1328                         ndir->itype.index.vcn_size_bits)) {
1329                 ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
1330                                 "different from expected VCN (0x%llx). "
1331                                 "Directory inode 0x%lx is corrupt or driver "
1332                                 "bug. ", (unsigned long long)
1333                                 sle64_to_cpu(ia->index_block_vcn),
1334                                 (unsigned long long)ia_pos >>
1335                                 ndir->itype.index.vcn_size_bits, vdir->i_ino);
1336                 goto err_out;
1337         }
1338         if (unlikely(le32_to_cpu(ia->index.allocated_size) + 0x18 !=
1339                         ndir->itype.index.block_size)) {
1340                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
1341                                 "0x%lx has a size (%u) differing from the "
1342                                 "directory specified size (%u). Directory "
1343                                 "inode is corrupt or driver bug.",
1344                                 (unsigned long long)ia_pos >>
1345                                 ndir->itype.index.vcn_size_bits, vdir->i_ino,
1346                                 le32_to_cpu(ia->index.allocated_size) + 0x18,
1347                                 ndir->itype.index.block_size);
1348                 goto err_out;
1349         }
1350         index_end = (u8*)ia + ndir->itype.index.block_size;
1351         if (unlikely(index_end > kaddr + PAGE_SIZE)) {
1352                 ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
1353                                 "0x%lx crosses page boundary. Impossible! "
1354                                 "Cannot access! This is probably a bug in the "
1355                                 "driver.", (unsigned long long)ia_pos >>
1356                                 ndir->itype.index.vcn_size_bits, vdir->i_ino);
1357                 goto err_out;
1358         }
1359         ia_start = ia_pos & ~(s64)(ndir->itype.index.block_size - 1);
1360         index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
1361         if (unlikely(index_end > (u8*)ia + ndir->itype.index.block_size)) {
1362                 ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of directory "
1363                                 "inode 0x%lx exceeds maximum size.",
1364                                 (unsigned long long)ia_pos >>
1365                                 ndir->itype.index.vcn_size_bits, vdir->i_ino);
1366                 goto err_out;
1367         }
1368         /* The first index entry in this index buffer. */
1369         ie = (INDEX_ENTRY*)((u8*)&ia->index +
1370                         le32_to_cpu(ia->index.entries_offset));
1371         /*
1372          * Loop until we exceed valid memory (corruption case) or until we
1373          * reach the last entry or until filldir tells us it has had enough
1374          * or signals an error (both covered by the rc test).
1375          */
1376         for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
1377                 ntfs_debug("In index allocation, offset 0x%llx.",
1378                                 (unsigned long long)ia_start +
1379                                 (unsigned long long)((u8*)ie - (u8*)ia));
1380                 /* Bounds checks. */
1381                 if (unlikely((u8*)ie < (u8*)ia || (u8*)ie +
1382                                 sizeof(INDEX_ENTRY_HEADER) > index_end ||
1383                                 (u8*)ie + le16_to_cpu(ie->key_length) >
1384                                 index_end))
1385                         goto err_out;
1386                 /* The last entry cannot contain a name. */
1387                 if (ie->flags & INDEX_ENTRY_END)
1388                         break;
1389                 /* Skip index block entry if continuing previous readdir. */
1390                 if (ia_pos - ia_start > (u8*)ie - (u8*)ia)
1391                         continue;
1392                 /* Advance the position even if going to skip the entry. */
1393                 actor->pos = (u8*)ie - (u8*)ia +
1394                                 (sle64_to_cpu(ia->index_block_vcn) <<
1395                                 ndir->itype.index.vcn_size_bits) +
1396                                 vol->mft_record_size;
1397                 /*
1398                  * Submit the name to the @filldir callback.  Note,
1399                  * ntfs_filldir() drops the lock on @ia_page but it retakes it
1400                  * before returning, unless a non-zero value is returned in
1401                  * which case the page is left unlocked.
1402                  */
1403                 rc = ntfs_filldir(vol, ndir, ia_page, ie, name, actor);
1404                 if (rc) {
1405                         /* @ia_page is already unlocked in this case. */
1406                         ntfs_unmap_page(ia_page);
1407                         ntfs_unmap_page(bmp_page);
1408                         iput(bmp_vi);
1409                         goto abort;
1410                 }
1411         }
1412         goto find_next_index_buffer;
1413 unm_EOD:
1414         if (ia_page) {
1415                 unlock_page(ia_page);
1416                 ntfs_unmap_page(ia_page);
1417         }
1418         ntfs_unmap_page(bmp_page);
1419         iput(bmp_vi);
1420 EOD:
1421         /* We are finished, set fpos to EOD. */
1422         actor->pos = i_size + vol->mft_record_size;
1423 abort:
1424         kfree(name);
1425         return 0;
1426 err_out:
1427         if (bmp_page) {
1428                 ntfs_unmap_page(bmp_page);
1429 iput_err_out:
1430                 iput(bmp_vi);
1431         }
1432         if (ia_page) {
1433                 unlock_page(ia_page);
1434                 ntfs_unmap_page(ia_page);
1435         }
1436         kfree(ir);
1437         kfree(name);
1438         if (ctx)
1439                 ntfs_attr_put_search_ctx(ctx);
1440         if (m)
1441                 unmap_mft_record(ndir);
1442         if (!err)
1443                 err = -EIO;
1444         ntfs_debug("Failed. Returning error code %i.", -err);
1445         return err;
1446 }
1447 
1448 /**
1449  * ntfs_dir_open - called when an inode is about to be opened
1450  * @vi:         inode to be opened
1451  * @filp:       file structure describing the inode
1452  *
1453  * Limit directory size to the page cache limit on architectures where unsigned
1454  * long is 32-bits. This is the most we can do for now without overflowing the
1455  * page cache page index. Doing it this way means we don't run into problems
1456  * because of existing too large directories. It would be better to allow the
1457  * user to read the accessible part of the directory but I doubt very much
1458  * anyone is going to hit this check on a 32-bit architecture, so there is no
1459  * point in adding the extra complexity required to support this.
1460  *
1461  * On 64-bit architectures, the check is hopefully optimized away by the
1462  * compiler.
1463  */
1464 static int ntfs_dir_open(struct inode *vi, struct file *filp)
1465 {
1466         if (sizeof(unsigned long) < 8) {
1467                 if (i_size_read(vi) > MAX_LFS_FILESIZE)
1468                         return -EFBIG;
1469         }
1470         return 0;
1471 }
1472 
1473 #ifdef NTFS_RW
1474 
1475 /**
1476  * ntfs_dir_fsync - sync a directory to disk
1477  * @filp:       directory to be synced
1478  * @dentry:     dentry describing the directory to sync
1479  * @datasync:   if non-zero only flush user data and not metadata
1480  *
1481  * Data integrity sync of a directory to disk.  Used for fsync, fdatasync, and
1482  * msync system calls.  This function is based on file.c::ntfs_file_fsync().
1483  *
1484  * Write the mft record and all associated extent mft records as well as the
1485  * $INDEX_ALLOCATION and $BITMAP attributes and then sync the block device.
1486  *
1487  * If @datasync is true, we do not wait on the inode(s) to be written out
1488  * but we always wait on the page cache pages to be written out.
1489  *
1490  * Note: In the past @filp could be NULL so we ignore it as we don't need it
1491  * anyway.
1492  *
1493  * Locking: Caller must hold i_mutex on the inode.
1494  *
1495  * TODO: We should probably also write all attribute/index inodes associated
1496  * with this inode but since we have no simple way of getting to them we ignore
1497  * this problem for now.  We do write the $BITMAP attribute if it is present
1498  * which is the important one for a directory so things are not too bad.
1499  */
1500 static int ntfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
1501                           int datasync)
1502 {
1503         struct inode *bmp_vi, *vi = filp->f_mapping->host;
1504         int err, ret;
1505         ntfs_attr na;
1506 
1507         ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
1508 
1509         err = filemap_write_and_wait_range(vi->i_mapping, start, end);
1510         if (err)
1511                 return err;
1512         inode_lock(vi);
1513 
1514         BUG_ON(!S_ISDIR(vi->i_mode));
1515         /* If the bitmap attribute inode is in memory sync it, too. */
1516         na.mft_no = vi->i_ino;
1517         na.type = AT_BITMAP;
1518         na.name = I30;
1519         na.name_len = 4;
1520         bmp_vi = ilookup5(vi->i_sb, vi->i_ino, (test_t)ntfs_test_inode, &na);
1521         if (bmp_vi) {
1522                 write_inode_now(bmp_vi, !datasync);
1523                 iput(bmp_vi);
1524         }
1525         ret = __ntfs_write_inode(vi, 1);
1526         write_inode_now(vi, !datasync);
1527         err = sync_blockdev(vi->i_sb->s_bdev);
1528         if (unlikely(err && !ret))
1529                 ret = err;
1530         if (likely(!ret))
1531                 ntfs_debug("Done.");
1532         else
1533                 ntfs_warning(vi->i_sb, "Failed to f%ssync inode 0x%lx.  Error "
1534                                 "%u.", datasync ? "data" : "", vi->i_ino, -ret);
1535         inode_unlock(vi);
1536         return ret;
1537 }
1538 
1539 #endif /* NTFS_RW */
1540 
1541 const struct file_operations ntfs_dir_ops = {
1542         .llseek         = generic_file_llseek,  /* Seek inside directory. */
1543         .read           = generic_read_dir,     /* Return -EISDIR. */
1544         .iterate        = ntfs_readdir,         /* Read directory contents. */
1545 #ifdef NTFS_RW
1546         .fsync          = ntfs_dir_fsync,       /* Sync a directory to disk. */
1547         /*.aio_fsync    = ,*/                   /* Sync all outstanding async
1548                                                    i/o operations on a kiocb. */
1549 #endif /* NTFS_RW */
1550         /*.ioctl        = ,*/                   /* Perform function on the
1551                                                    mounted filesystem. */
1552         .open           = ntfs_dir_open,        /* Open directory. */
1553 };
1554 

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