blob: 1ff7f90a18b0a79b2c46351f692f40f7824e6917 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/**
2 * attrib.c - NTFS attribute operations. Part of the Linux-NTFS project.
3 *
4 * Copyright (c) 2001-2004 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
25#include "attrib.h"
26#include "debug.h"
27#include "layout.h"
28#include "mft.h"
29#include "ntfs.h"
30#include "types.h"
31
32/**
33 * ntfs_map_runlist - map (a part of) a runlist of an ntfs inode
34 * @ni: ntfs inode for which to map (part of) a runlist
35 * @vcn: map runlist part containing this vcn
36 *
37 * Map the part of a runlist containing the @vcn of the ntfs inode @ni.
38 *
39 * Return 0 on success and -errno on error.
40 *
41 * Locking: - The runlist must be unlocked on entry and is unlocked on return.
42 * - This function takes the lock for writing and modifies the runlist.
43 */
44int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
45{
46 ntfs_inode *base_ni;
47 ntfs_attr_search_ctx *ctx;
48 MFT_RECORD *mrec;
49 int err = 0;
50
51 ntfs_debug("Mapping runlist part containing vcn 0x%llx.",
52 (unsigned long long)vcn);
53
54 if (!NInoAttr(ni))
55 base_ni = ni;
56 else
57 base_ni = ni->ext.base_ntfs_ino;
58
59 mrec = map_mft_record(base_ni);
60 if (IS_ERR(mrec))
61 return PTR_ERR(mrec);
62 ctx = ntfs_attr_get_search_ctx(base_ni, mrec);
63 if (unlikely(!ctx)) {
64 err = -ENOMEM;
65 goto err_out;
66 }
67 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
68 CASE_SENSITIVE, vcn, NULL, 0, ctx);
69 if (unlikely(err))
70 goto put_err_out;
71
72 down_write(&ni->runlist.lock);
73 /* Make sure someone else didn't do the work while we were sleeping. */
74 if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <=
75 LCN_RL_NOT_MAPPED)) {
76 runlist_element *rl;
77
78 rl = ntfs_mapping_pairs_decompress(ni->vol, ctx->attr,
79 ni->runlist.rl);
80 if (IS_ERR(rl))
81 err = PTR_ERR(rl);
82 else
83 ni->runlist.rl = rl;
84 }
85 up_write(&ni->runlist.lock);
86
87put_err_out:
88 ntfs_attr_put_search_ctx(ctx);
89err_out:
90 unmap_mft_record(base_ni);
91 return err;
92}
93
94/**
95 * ntfs_find_vcn - find a vcn in the runlist described by an ntfs inode
96 * @ni: ntfs inode describing the runlist to search
97 * @vcn: vcn to find
98 * @need_write: if false, lock for reading and if true, lock for writing
99 *
100 * Find the virtual cluster number @vcn in the runlist described by the ntfs
101 * inode @ni and return the address of the runlist element containing the @vcn.
102 * The runlist is left locked and the caller has to unlock it. If @need_write
103 * is true, the runlist is locked for writing and if @need_write is false, the
104 * runlist is locked for reading. In the error case, the runlist is not left
105 * locked.
106 *
107 * Note you need to distinguish between the lcn of the returned runlist element
108 * being >= 0 and LCN_HOLE. In the later case you have to return zeroes on
109 * read and allocate clusters on write.
110 *
111 * Return the runlist element containing the @vcn on success and
112 * ERR_PTR(-errno) on error. You need to test the return value with IS_ERR()
113 * to decide if the return is success or failure and PTR_ERR() to get to the
114 * error code if IS_ERR() is true.
115 *
116 * The possible error return codes are:
117 * -ENOENT - No such vcn in the runlist, i.e. @vcn is out of bounds.
118 * -ENOMEM - Not enough memory to map runlist.
119 * -EIO - Critical error (runlist/file is corrupt, i/o error, etc).
120 *
121 * Locking: - The runlist must be unlocked on entry.
122 * - On failing return, the runlist is unlocked.
123 * - On successful return, the runlist is locked. If @need_write us
124 * true, it is locked for writing. Otherwise is is locked for
125 * reading.
126 */
127runlist_element *ntfs_find_vcn(ntfs_inode *ni, const VCN vcn,
128 const BOOL need_write)
129{
130 runlist_element *rl;
131 int err = 0;
132 BOOL is_retry = FALSE;
133
134 ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, lock for %sing.",
135 ni->mft_no, (unsigned long long)vcn,
136 !need_write ? "read" : "writ");
137 BUG_ON(!ni);
138 BUG_ON(!NInoNonResident(ni));
139 BUG_ON(vcn < 0);
140lock_retry_remap:
141 if (!need_write)
142 down_read(&ni->runlist.lock);
143 else
144 down_write(&ni->runlist.lock);
145 rl = ni->runlist.rl;
146 if (likely(rl && vcn >= rl[0].vcn)) {
147 while (likely(rl->length)) {
148 if (likely(vcn < rl[1].vcn)) {
149 if (likely(rl->lcn >= LCN_HOLE)) {
150 ntfs_debug("Done.");
151 return rl;
152 }
153 break;
154 }
155 rl++;
156 }
157 if (likely(rl->lcn != LCN_RL_NOT_MAPPED)) {
158 if (likely(rl->lcn == LCN_ENOENT))
159 err = -ENOENT;
160 else
161 err = -EIO;
162 }
163 }
164 if (!need_write)
165 up_read(&ni->runlist.lock);
166 else
167 up_write(&ni->runlist.lock);
168 if (!err && !is_retry) {
169 /*
170 * The @vcn is in an unmapped region, map the runlist and
171 * retry.
172 */
173 err = ntfs_map_runlist(ni, vcn);
174 if (likely(!err)) {
175 is_retry = TRUE;
176 goto lock_retry_remap;
177 }
178 /*
179 * -EINVAL and -ENOENT coming from a failed mapping attempt are
180 * equivalent to i/o errors for us as they should not happen in
181 * our code paths.
182 */
183 if (err == -EINVAL || err == -ENOENT)
184 err = -EIO;
185 } else if (!err)
186 err = -EIO;
187 ntfs_error(ni->vol->sb, "Failed with error code %i.", err);
188 return ERR_PTR(err);
189}
190
191/**
192 * ntfs_attr_find - find (next) attribute in mft record
193 * @type: attribute type to find
194 * @name: attribute name to find (optional, i.e. NULL means don't care)
195 * @name_len: attribute name length (only needed if @name present)
196 * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present)
197 * @val: attribute value to find (optional, resident attributes only)
198 * @val_len: attribute value length
199 * @ctx: search context with mft record and attribute to search from
200 *
201 * You should not need to call this function directly. Use ntfs_attr_lookup()
202 * instead.
203 *
204 * ntfs_attr_find() takes a search context @ctx as parameter and searches the
205 * mft record specified by @ctx->mrec, beginning at @ctx->attr, for an
206 * attribute of @type, optionally @name and @val.
207 *
208 * If the attribute is found, ntfs_attr_find() returns 0 and @ctx->attr will
209 * point to the found attribute.
210 *
211 * If the attribute is not found, ntfs_attr_find() returns -ENOENT and
212 * @ctx->attr will point to the attribute before which the attribute being
213 * searched for would need to be inserted if such an action were to be desired.
214 *
215 * On actual error, ntfs_attr_find() returns -EIO. In this case @ctx->attr is
216 * undefined and in particular do not rely on it not changing.
217 *
218 * If @ctx->is_first is TRUE, the search begins with @ctx->attr itself. If it
219 * is FALSE, the search begins after @ctx->attr.
220 *
221 * If @ic is IGNORE_CASE, the @name comparisson is not case sensitive and
222 * @ctx->ntfs_ino must be set to the ntfs inode to which the mft record
223 * @ctx->mrec belongs. This is so we can get at the ntfs volume and hence at
224 * the upcase table. If @ic is CASE_SENSITIVE, the comparison is case
225 * sensitive. When @name is present, @name_len is the @name length in Unicode
226 * characters.
227 *
228 * If @name is not present (NULL), we assume that the unnamed attribute is
229 * being searched for.
230 *
231 * Finally, the resident attribute value @val is looked for, if present. If
232 * @val is not present (NULL), @val_len is ignored.
233 *
234 * ntfs_attr_find() only searches the specified mft record and it ignores the
235 * presence of an attribute list attribute (unless it is the one being searched
236 * for, obviously). If you need to take attribute lists into consideration,
237 * use ntfs_attr_lookup() instead (see below). This also means that you cannot
238 * use ntfs_attr_find() to search for extent records of non-resident
239 * attributes, as extents with lowest_vcn != 0 are usually described by the
240 * attribute list attribute only. - Note that it is possible that the first
241 * extent is only in the attribute list while the last extent is in the base
242 * mft record, so do not rely on being able to find the first extent in the
243 * base mft record.
244 *
245 * Warning: Never use @val when looking for attribute types which can be
246 * non-resident as this most likely will result in a crash!
247 */
248static int ntfs_attr_find(const ATTR_TYPE type, const ntfschar *name,
249 const u32 name_len, const IGNORE_CASE_BOOL ic,
250 const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx)
251{
252 ATTR_RECORD *a;
253 ntfs_volume *vol = ctx->ntfs_ino->vol;
254 ntfschar *upcase = vol->upcase;
255 u32 upcase_len = vol->upcase_len;
256
257 /*
258 * Iterate over attributes in mft record starting at @ctx->attr, or the
259 * attribute following that, if @ctx->is_first is TRUE.
260 */
261 if (ctx->is_first) {
262 a = ctx->attr;
263 ctx->is_first = FALSE;
264 } else
265 a = (ATTR_RECORD*)((u8*)ctx->attr +
266 le32_to_cpu(ctx->attr->length));
267 for (;; a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))) {
268 if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec +
269 le32_to_cpu(ctx->mrec->bytes_allocated))
270 break;
271 ctx->attr = a;
272 if (unlikely(le32_to_cpu(a->type) > le32_to_cpu(type) ||
273 a->type == AT_END))
274 return -ENOENT;
275 if (unlikely(!a->length))
276 break;
277 if (a->type != type)
278 continue;
279 /*
280 * If @name is present, compare the two names. If @name is
281 * missing, assume we want an unnamed attribute.
282 */
283 if (!name) {
284 /* The search failed if the found attribute is named. */
285 if (a->name_length)
286 return -ENOENT;
287 } else if (!ntfs_are_names_equal(name, name_len,
288 (ntfschar*)((u8*)a + le16_to_cpu(a->name_offset)),
289 a->name_length, ic, upcase, upcase_len)) {
290 register int rc;
291
292 rc = ntfs_collate_names(name, name_len,
293 (ntfschar*)((u8*)a +
294 le16_to_cpu(a->name_offset)),
295 a->name_length, 1, IGNORE_CASE,
296 upcase, upcase_len);
297 /*
298 * If @name collates before a->name, there is no
299 * matching attribute.
300 */
301 if (rc == -1)
302 return -ENOENT;
303 /* If the strings are not equal, continue search. */
304 if (rc)
305 continue;
306 rc = ntfs_collate_names(name, name_len,
307 (ntfschar*)((u8*)a +
308 le16_to_cpu(a->name_offset)),
309 a->name_length, 1, CASE_SENSITIVE,
310 upcase, upcase_len);
311 if (rc == -1)
312 return -ENOENT;
313 if (rc)
314 continue;
315 }
316 /*
317 * The names match or @name not present and attribute is
318 * unnamed. If no @val specified, we have found the attribute
319 * and are done.
320 */
321 if (!val)
322 return 0;
323 /* @val is present; compare values. */
324 else {
325 register int rc;
326
327 rc = memcmp(val, (u8*)a + le16_to_cpu(
328 a->data.resident.value_offset),
329 min_t(u32, val_len, le32_to_cpu(
330 a->data.resident.value_length)));
331 /*
332 * If @val collates before the current attribute's
333 * value, there is no matching attribute.
334 */
335 if (!rc) {
336 register u32 avl;
337
338 avl = le32_to_cpu(
339 a->data.resident.value_length);
340 if (val_len == avl)
341 return 0;
342 if (val_len < avl)
343 return -ENOENT;
344 } else if (rc < 0)
345 return -ENOENT;
346 }
347 }
348 ntfs_error(vol->sb, "Inode is corrupt. Run chkdsk.");
349 NVolSetErrors(vol);
350 return -EIO;
351}
352
353/**
354 * load_attribute_list - load an attribute list into memory
355 * @vol: ntfs volume from which to read
356 * @runlist: runlist of the attribute list
357 * @al_start: destination buffer
358 * @size: size of the destination buffer in bytes
359 * @initialized_size: initialized size of the attribute list
360 *
361 * Walk the runlist @runlist and load all clusters from it copying them into
362 * the linear buffer @al. The maximum number of bytes copied to @al is @size
363 * bytes. Note, @size does not need to be a multiple of the cluster size. If
364 * @initialized_size is less than @size, the region in @al between
365 * @initialized_size and @size will be zeroed and not read from disk.
366 *
367 * Return 0 on success or -errno on error.
368 */
369int load_attribute_list(ntfs_volume *vol, runlist *runlist, u8 *al_start,
370 const s64 size, const s64 initialized_size)
371{
372 LCN lcn;
373 u8 *al = al_start;
374 u8 *al_end = al + initialized_size;
375 runlist_element *rl;
376 struct buffer_head *bh;
377 struct super_block *sb;
378 unsigned long block_size;
379 unsigned long block, max_block;
380 int err = 0;
381 unsigned char block_size_bits;
382
383 ntfs_debug("Entering.");
384 if (!vol || !runlist || !al || size <= 0 || initialized_size < 0 ||
385 initialized_size > size)
386 return -EINVAL;
387 if (!initialized_size) {
388 memset(al, 0, size);
389 return 0;
390 }
391 sb = vol->sb;
392 block_size = sb->s_blocksize;
393 block_size_bits = sb->s_blocksize_bits;
394 down_read(&runlist->lock);
395 rl = runlist->rl;
396 /* Read all clusters specified by the runlist one run at a time. */
397 while (rl->length) {
398 lcn = ntfs_rl_vcn_to_lcn(rl, rl->vcn);
399 ntfs_debug("Reading vcn = 0x%llx, lcn = 0x%llx.",
400 (unsigned long long)rl->vcn,
401 (unsigned long long)lcn);
402 /* The attribute list cannot be sparse. */
403 if (lcn < 0) {
404 ntfs_error(sb, "ntfs_rl_vcn_to_lcn() failed. Cannot "
405 "read attribute list.");
406 goto err_out;
407 }
408 block = lcn << vol->cluster_size_bits >> block_size_bits;
409 /* Read the run from device in chunks of block_size bytes. */
410 max_block = block + (rl->length << vol->cluster_size_bits >>
411 block_size_bits);
412 ntfs_debug("max_block = 0x%lx.", max_block);
413 do {
414 ntfs_debug("Reading block = 0x%lx.", block);
415 bh = sb_bread(sb, block);
416 if (!bh) {
417 ntfs_error(sb, "sb_bread() failed. Cannot "
418 "read attribute list.");
419 goto err_out;
420 }
421 if (al + block_size >= al_end)
422 goto do_final;
423 memcpy(al, bh->b_data, block_size);
424 brelse(bh);
425 al += block_size;
426 } while (++block < max_block);
427 rl++;
428 }
429 if (initialized_size < size) {
430initialize:
431 memset(al_start + initialized_size, 0, size - initialized_size);
432 }
433done:
434 up_read(&runlist->lock);
435 return err;
436do_final:
437 if (al < al_end) {
438 /*
439 * Partial block.
440 *
441 * Note: The attribute list can be smaller than its allocation
442 * by multiple clusters. This has been encountered by at least
443 * two people running Windows XP, thus we cannot do any
444 * truncation sanity checking here. (AIA)
445 */
446 memcpy(al, bh->b_data, al_end - al);
447 brelse(bh);
448 if (initialized_size < size)
449 goto initialize;
450 goto done;
451 }
452 brelse(bh);
453 /* Real overflow! */
454 ntfs_error(sb, "Attribute list buffer overflow. Read attribute list "
455 "is truncated.");
456err_out:
457 err = -EIO;
458 goto done;
459}
460
461/**
462 * ntfs_external_attr_find - find an attribute in the attribute list of an inode
463 * @type: attribute type to find
464 * @name: attribute name to find (optional, i.e. NULL means don't care)
465 * @name_len: attribute name length (only needed if @name present)
466 * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present)
467 * @lowest_vcn: lowest vcn to find (optional, non-resident attributes only)
468 * @val: attribute value to find (optional, resident attributes only)
469 * @val_len: attribute value length
470 * @ctx: search context with mft record and attribute to search from
471 *
472 * You should not need to call this function directly. Use ntfs_attr_lookup()
473 * instead.
474 *
475 * Find an attribute by searching the attribute list for the corresponding
476 * attribute list entry. Having found the entry, map the mft record if the
477 * attribute is in a different mft record/inode, ntfs_attr_find() the attribute
478 * in there and return it.
479 *
480 * On first search @ctx->ntfs_ino must be the base mft record and @ctx must
481 * have been obtained from a call to ntfs_attr_get_search_ctx(). On subsequent
482 * calls @ctx->ntfs_ino can be any extent inode, too (@ctx->base_ntfs_ino is
483 * then the base inode).
484 *
485 * After finishing with the attribute/mft record you need to call
486 * ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any
487 * mapped inodes, etc).
488 *
489 * If the attribute is found, ntfs_external_attr_find() returns 0 and
490 * @ctx->attr will point to the found attribute. @ctx->mrec will point to the
491 * mft record in which @ctx->attr is located and @ctx->al_entry will point to
492 * the attribute list entry for the attribute.
493 *
494 * If the attribute is not found, ntfs_external_attr_find() returns -ENOENT and
495 * @ctx->attr will point to the attribute in the base mft record before which
496 * the attribute being searched for would need to be inserted if such an action
497 * were to be desired. @ctx->mrec will point to the mft record in which
498 * @ctx->attr is located and @ctx->al_entry will point to the attribute list
499 * entry of the attribute before which the attribute being searched for would
500 * need to be inserted if such an action were to be desired.
501 *
502 * Thus to insert the not found attribute, one wants to add the attribute to
503 * @ctx->mrec (the base mft record) and if there is not enough space, the
504 * attribute should be placed in a newly allocated extent mft record. The
505 * attribute list entry for the inserted attribute should be inserted in the
506 * attribute list attribute at @ctx->al_entry.
507 *
508 * On actual error, ntfs_external_attr_find() returns -EIO. In this case
509 * @ctx->attr is undefined and in particular do not rely on it not changing.
510 */
511static int ntfs_external_attr_find(const ATTR_TYPE type,
512 const ntfschar *name, const u32 name_len,
513 const IGNORE_CASE_BOOL ic, const VCN lowest_vcn,
514 const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx)
515{
516 ntfs_inode *base_ni, *ni;
517 ntfs_volume *vol;
518 ATTR_LIST_ENTRY *al_entry, *next_al_entry;
519 u8 *al_start, *al_end;
520 ATTR_RECORD *a;
521 ntfschar *al_name;
522 u32 al_name_len;
523 int err = 0;
524 static const char *es = " Unmount and run chkdsk.";
525
526 ni = ctx->ntfs_ino;
527 base_ni = ctx->base_ntfs_ino;
528 ntfs_debug("Entering for inode 0x%lx, type 0x%x.", ni->mft_no, type);
529 if (!base_ni) {
530 /* First call happens with the base mft record. */
531 base_ni = ctx->base_ntfs_ino = ctx->ntfs_ino;
532 ctx->base_mrec = ctx->mrec;
533 }
534 if (ni == base_ni)
535 ctx->base_attr = ctx->attr;
536 if (type == AT_END)
537 goto not_found;
538 vol = base_ni->vol;
539 al_start = base_ni->attr_list;
540 al_end = al_start + base_ni->attr_list_size;
541 if (!ctx->al_entry)
542 ctx->al_entry = (ATTR_LIST_ENTRY*)al_start;
543 /*
544 * Iterate over entries in attribute list starting at @ctx->al_entry,
545 * or the entry following that, if @ctx->is_first is TRUE.
546 */
547 if (ctx->is_first) {
548 al_entry = ctx->al_entry;
549 ctx->is_first = FALSE;
550 } else
551 al_entry = (ATTR_LIST_ENTRY*)((u8*)ctx->al_entry +
552 le16_to_cpu(ctx->al_entry->length));
553 for (;; al_entry = next_al_entry) {
554 /* Out of bounds check. */
555 if ((u8*)al_entry < base_ni->attr_list ||
556 (u8*)al_entry > al_end)
557 break; /* Inode is corrupt. */
558 ctx->al_entry = al_entry;
559 /* Catch the end of the attribute list. */
560 if ((u8*)al_entry == al_end)
561 goto not_found;
562 if (!al_entry->length)
563 break;
564 if ((u8*)al_entry + 6 > al_end || (u8*)al_entry +
565 le16_to_cpu(al_entry->length) > al_end)
566 break;
567 next_al_entry = (ATTR_LIST_ENTRY*)((u8*)al_entry +
568 le16_to_cpu(al_entry->length));
569 if (le32_to_cpu(al_entry->type) > le32_to_cpu(type))
570 goto not_found;
571 if (type != al_entry->type)
572 continue;
573 /*
574 * If @name is present, compare the two names. If @name is
575 * missing, assume we want an unnamed attribute.
576 */
577 al_name_len = al_entry->name_length;
578 al_name = (ntfschar*)((u8*)al_entry + al_entry->name_offset);
579 if (!name) {
580 if (al_name_len)
581 goto not_found;
582 } else if (!ntfs_are_names_equal(al_name, al_name_len, name,
583 name_len, ic, vol->upcase, vol->upcase_len)) {
584 register int rc;
585
586 rc = ntfs_collate_names(name, name_len, al_name,
587 al_name_len, 1, IGNORE_CASE,
588 vol->upcase, vol->upcase_len);
589 /*
590 * If @name collates before al_name, there is no
591 * matching attribute.
592 */
593 if (rc == -1)
594 goto not_found;
595 /* If the strings are not equal, continue search. */
596 if (rc)
597 continue;
598 /*
599 * FIXME: Reverse engineering showed 0, IGNORE_CASE but
600 * that is inconsistent with ntfs_attr_find(). The
601 * subsequent rc checks were also different. Perhaps I
602 * made a mistake in one of the two. Need to recheck
603 * which is correct or at least see what is going on...
604 * (AIA)
605 */
606 rc = ntfs_collate_names(name, name_len, al_name,
607 al_name_len, 1, CASE_SENSITIVE,
608 vol->upcase, vol->upcase_len);
609 if (rc == -1)
610 goto not_found;
611 if (rc)
612 continue;
613 }
614 /*
615 * The names match or @name not present and attribute is
616 * unnamed. Now check @lowest_vcn. Continue search if the
617 * next attribute list entry still fits @lowest_vcn. Otherwise
618 * we have reached the right one or the search has failed.
619 */
620 if (lowest_vcn && (u8*)next_al_entry >= al_start &&
621 (u8*)next_al_entry + 6 < al_end &&
622 (u8*)next_al_entry + le16_to_cpu(
623 next_al_entry->length) <= al_end &&
624 sle64_to_cpu(next_al_entry->lowest_vcn) <=
625 lowest_vcn &&
626 next_al_entry->type == al_entry->type &&
627 next_al_entry->name_length == al_name_len &&
628 ntfs_are_names_equal((ntfschar*)((u8*)
629 next_al_entry +
630 next_al_entry->name_offset),
631 next_al_entry->name_length,
632 al_name, al_name_len, CASE_SENSITIVE,
633 vol->upcase, vol->upcase_len))
634 continue;
635 if (MREF_LE(al_entry->mft_reference) == ni->mft_no) {
636 if (MSEQNO_LE(al_entry->mft_reference) != ni->seq_no) {
637 ntfs_error(vol->sb, "Found stale mft "
638 "reference in attribute list "
639 "of base inode 0x%lx.%s",
640 base_ni->mft_no, es);
641 err = -EIO;
642 break;
643 }
644 } else { /* Mft references do not match. */
645 /* If there is a mapped record unmap it first. */
646 if (ni != base_ni)
647 unmap_extent_mft_record(ni);
648 /* Do we want the base record back? */
649 if (MREF_LE(al_entry->mft_reference) ==
650 base_ni->mft_no) {
651 ni = ctx->ntfs_ino = base_ni;
652 ctx->mrec = ctx->base_mrec;
653 } else {
654 /* We want an extent record. */
655 ctx->mrec = map_extent_mft_record(base_ni,
656 le64_to_cpu(
657 al_entry->mft_reference), &ni);
658 if (IS_ERR(ctx->mrec)) {
659 ntfs_error(vol->sb, "Failed to map "
660 "extent mft record "
661 "0x%lx of base inode "
662 "0x%lx.%s",
663 MREF_LE(al_entry->
664 mft_reference),
665 base_ni->mft_no, es);
666 err = PTR_ERR(ctx->mrec);
667 if (err == -ENOENT)
668 err = -EIO;
669 /* Cause @ctx to be sanitized below. */
670 ni = NULL;
671 break;
672 }
673 ctx->ntfs_ino = ni;
674 }
675 ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec +
676 le16_to_cpu(ctx->mrec->attrs_offset));
677 }
678 /*
679 * ctx->vfs_ino, ctx->mrec, and ctx->attr now point to the
680 * mft record containing the attribute represented by the
681 * current al_entry.
682 */
683 /*
684 * We could call into ntfs_attr_find() to find the right
685 * attribute in this mft record but this would be less
686 * efficient and not quite accurate as ntfs_attr_find() ignores
687 * the attribute instance numbers for example which become
688 * important when one plays with attribute lists. Also,
689 * because a proper match has been found in the attribute list
690 * entry above, the comparison can now be optimized. So it is
691 * worth re-implementing a simplified ntfs_attr_find() here.
692 */
693 a = ctx->attr;
694 /*
695 * Use a manual loop so we can still use break and continue
696 * with the same meanings as above.
697 */
698do_next_attr_loop:
699 if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec +
700 le32_to_cpu(ctx->mrec->bytes_allocated))
701 break;
702 if (a->type == AT_END)
703 continue;
704 if (!a->length)
705 break;
706 if (al_entry->instance != a->instance)
707 goto do_next_attr;
708 /*
709 * If the type and/or the name are mismatched between the
710 * attribute list entry and the attribute record, there is
711 * corruption so we break and return error EIO.
712 */
713 if (al_entry->type != a->type)
714 break;
715 if (!ntfs_are_names_equal((ntfschar*)((u8*)a +
716 le16_to_cpu(a->name_offset)), a->name_length,
717 al_name, al_name_len, CASE_SENSITIVE,
718 vol->upcase, vol->upcase_len))
719 break;
720 ctx->attr = a;
721 /*
722 * If no @val specified or @val specified and it matches, we
723 * have found it!
724 */
725 if (!val || (!a->non_resident && le32_to_cpu(
726 a->data.resident.value_length) == val_len &&
727 !memcmp((u8*)a +
728 le16_to_cpu(a->data.resident.value_offset),
729 val, val_len))) {
730 ntfs_debug("Done, found.");
731 return 0;
732 }
733do_next_attr:
734 /* Proceed to the next attribute in the current mft record. */
735 a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length));
736 goto do_next_attr_loop;
737 }
738 if (!err) {
739 ntfs_error(vol->sb, "Base inode 0x%lx contains corrupt "
740 "attribute list attribute.%s", base_ni->mft_no,
741 es);
742 err = -EIO;
743 }
744 if (ni != base_ni) {
745 if (ni)
746 unmap_extent_mft_record(ni);
747 ctx->ntfs_ino = base_ni;
748 ctx->mrec = ctx->base_mrec;
749 ctx->attr = ctx->base_attr;
750 }
751 if (err != -ENOMEM)
752 NVolSetErrors(vol);
753 return err;
754not_found:
755 /*
756 * If we were looking for AT_END, we reset the search context @ctx and
757 * use ntfs_attr_find() to seek to the end of the base mft record.
758 */
759 if (type == AT_END) {
760 ntfs_attr_reinit_search_ctx(ctx);
761 return ntfs_attr_find(AT_END, name, name_len, ic, val, val_len,
762 ctx);
763 }
764 /*
765 * The attribute was not found. Before we return, we want to ensure
766 * @ctx->mrec and @ctx->attr indicate the position at which the
767 * attribute should be inserted in the base mft record. Since we also
768 * want to preserve @ctx->al_entry we cannot reinitialize the search
769 * context using ntfs_attr_reinit_search_ctx() as this would set
770 * @ctx->al_entry to NULL. Thus we do the necessary bits manually (see
771 * ntfs_attr_init_search_ctx() below). Note, we _only_ preserve
772 * @ctx->al_entry as the remaining fields (base_*) are identical to
773 * their non base_ counterparts and we cannot set @ctx->base_attr
774 * correctly yet as we do not know what @ctx->attr will be set to by
775 * the call to ntfs_attr_find() below.
776 */
777 if (ni != base_ni)
778 unmap_extent_mft_record(ni);
779 ctx->mrec = ctx->base_mrec;
780 ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec +
781 le16_to_cpu(ctx->mrec->attrs_offset));
782 ctx->is_first = TRUE;
783 ctx->ntfs_ino = base_ni;
784 ctx->base_ntfs_ino = NULL;
785 ctx->base_mrec = NULL;
786 ctx->base_attr = NULL;
787 /*
788 * In case there are multiple matches in the base mft record, need to
789 * keep enumerating until we get an attribute not found response (or
790 * another error), otherwise we would keep returning the same attribute
791 * over and over again and all programs using us for enumeration would
792 * lock up in a tight loop.
793 */
794 do {
795 err = ntfs_attr_find(type, name, name_len, ic, val, val_len,
796 ctx);
797 } while (!err);
798 ntfs_debug("Done, not found.");
799 return err;
800}
801
802/**
803 * ntfs_attr_lookup - find an attribute in an ntfs inode
804 * @type: attribute type to find
805 * @name: attribute name to find (optional, i.e. NULL means don't care)
806 * @name_len: attribute name length (only needed if @name present)
807 * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present)
808 * @lowest_vcn: lowest vcn to find (optional, non-resident attributes only)
809 * @val: attribute value to find (optional, resident attributes only)
810 * @val_len: attribute value length
811 * @ctx: search context with mft record and attribute to search from
812 *
813 * Find an attribute in an ntfs inode. On first search @ctx->ntfs_ino must
814 * be the base mft record and @ctx must have been obtained from a call to
815 * ntfs_attr_get_search_ctx().
816 *
817 * This function transparently handles attribute lists and @ctx is used to
818 * continue searches where they were left off at.
819 *
820 * After finishing with the attribute/mft record you need to call
821 * ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any
822 * mapped inodes, etc).
823 *
824 * Return 0 if the search was successful and -errno if not.
825 *
826 * When 0, @ctx->attr is the found attribute and it is in mft record
827 * @ctx->mrec. If an attribute list attribute is present, @ctx->al_entry is
828 * the attribute list entry of the found attribute.
829 *
830 * When -ENOENT, @ctx->attr is the attribute which collates just after the
831 * attribute being searched for, i.e. if one wants to add the attribute to the
832 * mft record this is the correct place to insert it into. If an attribute
833 * list attribute is present, @ctx->al_entry is the attribute list entry which
834 * collates just after the attribute list entry of the attribute being searched
835 * for, i.e. if one wants to add the attribute to the mft record this is the
836 * correct place to insert its attribute list entry into.
837 *
838 * When -errno != -ENOENT, an error occured during the lookup. @ctx->attr is
839 * then undefined and in particular you should not rely on it not changing.
840 */
841int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name,
842 const u32 name_len, const IGNORE_CASE_BOOL ic,
843 const VCN lowest_vcn, const u8 *val, const u32 val_len,
844 ntfs_attr_search_ctx *ctx)
845{
846 ntfs_inode *base_ni;
847
848 ntfs_debug("Entering.");
849 if (ctx->base_ntfs_ino)
850 base_ni = ctx->base_ntfs_ino;
851 else
852 base_ni = ctx->ntfs_ino;
853 /* Sanity check, just for debugging really. */
854 BUG_ON(!base_ni);
855 if (!NInoAttrList(base_ni) || type == AT_ATTRIBUTE_LIST)
856 return ntfs_attr_find(type, name, name_len, ic, val, val_len,
857 ctx);
858 return ntfs_external_attr_find(type, name, name_len, ic, lowest_vcn,
859 val, val_len, ctx);
860}
861
862/**
863 * ntfs_attr_init_search_ctx - initialize an attribute search context
864 * @ctx: attribute search context to initialize
865 * @ni: ntfs inode with which to initialize the search context
866 * @mrec: mft record with which to initialize the search context
867 *
868 * Initialize the attribute search context @ctx with @ni and @mrec.
869 */
870static inline void ntfs_attr_init_search_ctx(ntfs_attr_search_ctx *ctx,
871 ntfs_inode *ni, MFT_RECORD *mrec)
872{
873 ctx->mrec = mrec;
874 /* Sanity checks are performed elsewhere. */
875 ctx->attr = (ATTR_RECORD*)((u8*)mrec + le16_to_cpu(mrec->attrs_offset));
876 ctx->is_first = TRUE;
877 ctx->ntfs_ino = ni;
878 ctx->al_entry = NULL;
879 ctx->base_ntfs_ino = NULL;
880 ctx->base_mrec = NULL;
881 ctx->base_attr = NULL;
882}
883
884/**
885 * ntfs_attr_reinit_search_ctx - reinitialize an attribute search context
886 * @ctx: attribute search context to reinitialize
887 *
888 * Reinitialize the attribute search context @ctx, unmapping an associated
889 * extent mft record if present, and initialize the search context again.
890 *
891 * This is used when a search for a new attribute is being started to reset
892 * the search context to the beginning.
893 */
894void ntfs_attr_reinit_search_ctx(ntfs_attr_search_ctx *ctx)
895{
896 if (likely(!ctx->base_ntfs_ino)) {
897 /* No attribute list. */
898 ctx->is_first = TRUE;
899 /* Sanity checks are performed elsewhere. */
900 ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec +
901 le16_to_cpu(ctx->mrec->attrs_offset));
902 /*
903 * This needs resetting due to ntfs_external_attr_find() which
904 * can leave it set despite having zeroed ctx->base_ntfs_ino.
905 */
906 ctx->al_entry = NULL;
907 return;
908 } /* Attribute list. */
909 if (ctx->ntfs_ino != ctx->base_ntfs_ino)
910 unmap_extent_mft_record(ctx->ntfs_ino);
911 ntfs_attr_init_search_ctx(ctx, ctx->base_ntfs_ino, ctx->base_mrec);
912 return;
913}
914
915/**
916 * ntfs_attr_get_search_ctx - allocate/initialize a new attribute search context
917 * @ni: ntfs inode with which to initialize the search context
918 * @mrec: mft record with which to initialize the search context
919 *
920 * Allocate a new attribute search context, initialize it with @ni and @mrec,
921 * and return it. Return NULL if allocation failed.
922 */
923ntfs_attr_search_ctx *ntfs_attr_get_search_ctx(ntfs_inode *ni, MFT_RECORD *mrec)
924{
925 ntfs_attr_search_ctx *ctx;
926
927 ctx = kmem_cache_alloc(ntfs_attr_ctx_cache, SLAB_NOFS);
928 if (ctx)
929 ntfs_attr_init_search_ctx(ctx, ni, mrec);
930 return ctx;
931}
932
933/**
934 * ntfs_attr_put_search_ctx - release an attribute search context
935 * @ctx: attribute search context to free
936 *
937 * Release the attribute search context @ctx, unmapping an associated extent
938 * mft record if present.
939 */
940void ntfs_attr_put_search_ctx(ntfs_attr_search_ctx *ctx)
941{
942 if (ctx->base_ntfs_ino && ctx->ntfs_ino != ctx->base_ntfs_ino)
943 unmap_extent_mft_record(ctx->ntfs_ino);
944 kmem_cache_free(ntfs_attr_ctx_cache, ctx);
945 return;
946}
947
948/**
949 * ntfs_attr_find_in_attrdef - find an attribute in the $AttrDef system file
950 * @vol: ntfs volume to which the attribute belongs
951 * @type: attribute type which to find
952 *
953 * Search for the attribute definition record corresponding to the attribute
954 * @type in the $AttrDef system file.
955 *
956 * Return the attribute type definition record if found and NULL if not found.
957 */
958static ATTR_DEF *ntfs_attr_find_in_attrdef(const ntfs_volume *vol,
959 const ATTR_TYPE type)
960{
961 ATTR_DEF *ad;
962
963 BUG_ON(!vol->attrdef);
964 BUG_ON(!type);
965 for (ad = vol->attrdef; (u8*)ad - (u8*)vol->attrdef <
966 vol->attrdef_size && ad->type; ++ad) {
967 /* We have not found it yet, carry on searching. */
968 if (likely(le32_to_cpu(ad->type) < le32_to_cpu(type)))
969 continue;
970 /* We found the attribute; return it. */
971 if (likely(ad->type == type))
972 return ad;
973 /* We have gone too far already. No point in continuing. */
974 break;
975 }
976 /* Attribute not found. */
977 ntfs_debug("Attribute type 0x%x not found in $AttrDef.",
978 le32_to_cpu(type));
979 return NULL;
980}
981
982/**
983 * ntfs_attr_size_bounds_check - check a size of an attribute type for validity
984 * @vol: ntfs volume to which the attribute belongs
985 * @type: attribute type which to check
986 * @size: size which to check
987 *
988 * Check whether the @size in bytes is valid for an attribute of @type on the
989 * ntfs volume @vol. This information is obtained from $AttrDef system file.
990 *
991 * Return 0 if valid, -ERANGE if not valid, or -ENOENT if the attribute is not
992 * listed in $AttrDef.
993 */
994int ntfs_attr_size_bounds_check(const ntfs_volume *vol, const ATTR_TYPE type,
995 const s64 size)
996{
997 ATTR_DEF *ad;
998
999 BUG_ON(size < 0);
1000 /*
1001 * $ATTRIBUTE_LIST has a maximum size of 256kiB, but this is not
1002 * listed in $AttrDef.
1003 */
1004 if (unlikely(type == AT_ATTRIBUTE_LIST && size > 256 * 1024))
1005 return -ERANGE;
1006 /* Get the $AttrDef entry for the attribute @type. */
1007 ad = ntfs_attr_find_in_attrdef(vol, type);
1008 if (unlikely(!ad))
1009 return -ENOENT;
1010 /* Do the bounds check. */
1011 if (((sle64_to_cpu(ad->min_size) > 0) &&
1012 size < sle64_to_cpu(ad->min_size)) ||
1013 ((sle64_to_cpu(ad->max_size) > 0) && size >
1014 sle64_to_cpu(ad->max_size)))
1015 return -ERANGE;
1016 return 0;
1017}
1018
1019/**
1020 * ntfs_attr_can_be_non_resident - check if an attribute can be non-resident
1021 * @vol: ntfs volume to which the attribute belongs
1022 * @type: attribute type which to check
1023 *
1024 * Check whether the attribute of @type on the ntfs volume @vol is allowed to
1025 * be non-resident. This information is obtained from $AttrDef system file.
1026 *
1027 * Return 0 if the attribute is allowed to be non-resident, -EPERM if not, or
1028 * -ENOENT if the attribute is not listed in $AttrDef.
1029 */
1030int ntfs_attr_can_be_non_resident(const ntfs_volume *vol, const ATTR_TYPE type)
1031{
1032 ATTR_DEF *ad;
1033
1034 /*
1035 * $DATA is always allowed to be non-resident even if $AttrDef does not
1036 * specify this in the flags of the $DATA attribute definition record.
1037 */
1038 if (type == AT_DATA)
1039 return 0;
1040 /* Find the attribute definition record in $AttrDef. */
1041 ad = ntfs_attr_find_in_attrdef(vol, type);
1042 if (unlikely(!ad))
1043 return -ENOENT;
1044 /* Check the flags and return the result. */
1045 if (ad->flags & CAN_BE_NON_RESIDENT)
1046 return 0;
1047 return -EPERM;
1048}
1049
1050/**
1051 * ntfs_attr_can_be_resident - check if an attribute can be resident
1052 * @vol: ntfs volume to which the attribute belongs
1053 * @type: attribute type which to check
1054 *
1055 * Check whether the attribute of @type on the ntfs volume @vol is allowed to
1056 * be resident. This information is derived from our ntfs knowledge and may
1057 * not be completely accurate, especially when user defined attributes are
1058 * present. Basically we allow everything to be resident except for index
1059 * allocation and $EA attributes.
1060 *
1061 * Return 0 if the attribute is allowed to be non-resident and -EPERM if not.
1062 *
1063 * Warning: In the system file $MFT the attribute $Bitmap must be non-resident
1064 * otherwise windows will not boot (blue screen of death)! We cannot
1065 * check for this here as we do not know which inode's $Bitmap is
1066 * being asked about so the caller needs to special case this.
1067 */
1068int ntfs_attr_can_be_resident(const ntfs_volume *vol, const ATTR_TYPE type)
1069{
1070 if (type != AT_INDEX_ALLOCATION && type != AT_EA)
1071 return 0;
1072 return -EPERM;
1073}
1074
1075/**
1076 * ntfs_attr_record_resize - resize an attribute record
1077 * @m: mft record containing attribute record
1078 * @a: attribute record to resize
1079 * @new_size: new size in bytes to which to resize the attribute record @a
1080 *
1081 * Resize the attribute record @a, i.e. the resident part of the attribute, in
1082 * the mft record @m to @new_size bytes.
1083 *
1084 * Return 0 on success and -errno on error. The following error codes are
1085 * defined:
1086 * -ENOSPC - Not enough space in the mft record @m to perform the resize.
1087 *
1088 * Note: On error, no modifications have been performed whatsoever.
1089 *
1090 * Warning: If you make a record smaller without having copied all the data you
1091 * are interested in the data may be overwritten.
1092 */
1093int ntfs_attr_record_resize(MFT_RECORD *m, ATTR_RECORD *a, u32 new_size)
1094{
1095 ntfs_debug("Entering for new_size %u.", new_size);
1096 /* Align to 8 bytes if it is not already done. */
1097 if (new_size & 7)
1098 new_size = (new_size + 7) & ~7;
1099 /* If the actual attribute length has changed, move things around. */
1100 if (new_size != le32_to_cpu(a->length)) {
1101 u32 new_muse = le32_to_cpu(m->bytes_in_use) -
1102 le32_to_cpu(a->length) + new_size;
1103 /* Not enough space in this mft record. */
1104 if (new_muse > le32_to_cpu(m->bytes_allocated))
1105 return -ENOSPC;
1106 /* Move attributes following @a to their new location. */
1107 memmove((u8*)a + new_size, (u8*)a + le32_to_cpu(a->length),
1108 le32_to_cpu(m->bytes_in_use) - ((u8*)a -
1109 (u8*)m) - le32_to_cpu(a->length));
1110 /* Adjust @m to reflect the change in used space. */
1111 m->bytes_in_use = cpu_to_le32(new_muse);
1112 /* Adjust @a to reflect the new size. */
1113 if (new_size >= offsetof(ATTR_REC, length) + sizeof(a->length))
1114 a->length = cpu_to_le32(new_size);
1115 }
1116 return 0;
1117}
1118
1119/**
1120 * ntfs_attr_set - fill (a part of) an attribute with a byte
1121 * @ni: ntfs inode describing the attribute to fill
1122 * @ofs: offset inside the attribute at which to start to fill
1123 * @cnt: number of bytes to fill
1124 * @val: the unsigned 8-bit value with which to fill the attribute
1125 *
1126 * Fill @cnt bytes of the attribute described by the ntfs inode @ni starting at
1127 * byte offset @ofs inside the attribute with the constant byte @val.
1128 *
1129 * This function is effectively like memset() applied to an ntfs attribute.
1130 *
1131 * Return 0 on success and -errno on error. An error code of -ESPIPE means
1132 * that @ofs + @cnt were outside the end of the attribute and no write was
1133 * performed.
1134 */
1135int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
1136{
1137 ntfs_volume *vol = ni->vol;
1138 struct address_space *mapping;
1139 struct page *page;
1140 u8 *kaddr;
1141 pgoff_t idx, end;
1142 unsigned int start_ofs, end_ofs, size;
1143
1144 ntfs_debug("Entering for ofs 0x%llx, cnt 0x%llx, val 0x%hx.",
1145 (long long)ofs, (long long)cnt, val);
1146 BUG_ON(ofs < 0);
1147 BUG_ON(cnt < 0);
1148 if (!cnt)
1149 goto done;
1150 mapping = VFS_I(ni)->i_mapping;
1151 /* Work out the starting index and page offset. */
1152 idx = ofs >> PAGE_CACHE_SHIFT;
1153 start_ofs = ofs & ~PAGE_CACHE_MASK;
1154 /* Work out the ending index and page offset. */
1155 end = ofs + cnt;
1156 end_ofs = end & ~PAGE_CACHE_MASK;
1157 /* If the end is outside the inode size return -ESPIPE. */
1158 if (unlikely(end > VFS_I(ni)->i_size)) {
1159 ntfs_error(vol->sb, "Request exceeds end of attribute.");
1160 return -ESPIPE;
1161 }
1162 end >>= PAGE_CACHE_SHIFT;
1163 /* If there is a first partial page, need to do it the slow way. */
1164 if (start_ofs) {
1165 page = read_cache_page(mapping, idx,
1166 (filler_t*)mapping->a_ops->readpage, NULL);
1167 if (IS_ERR(page)) {
1168 ntfs_error(vol->sb, "Failed to read first partial "
1169 "page (sync error, index 0x%lx).", idx);
1170 return PTR_ERR(page);
1171 }
1172 wait_on_page_locked(page);
1173 if (unlikely(!PageUptodate(page))) {
1174 ntfs_error(vol->sb, "Failed to read first partial page "
1175 "(async error, index 0x%lx).", idx);
1176 page_cache_release(page);
1177 return PTR_ERR(page);
1178 }
1179 /*
1180 * If the last page is the same as the first page, need to
1181 * limit the write to the end offset.
1182 */
1183 size = PAGE_CACHE_SIZE;
1184 if (idx == end)
1185 size = end_ofs;
1186 kaddr = kmap_atomic(page, KM_USER0);
1187 memset(kaddr + start_ofs, val, size - start_ofs);
1188 flush_dcache_page(page);
1189 kunmap_atomic(kaddr, KM_USER0);
1190 set_page_dirty(page);
1191 page_cache_release(page);
1192 if (idx == end)
1193 goto done;
1194 idx++;
1195 }
1196 /* Do the whole pages the fast way. */
1197 for (; idx < end; idx++) {
1198 /* Find or create the current page. (The page is locked.) */
1199 page = grab_cache_page(mapping, idx);
1200 if (unlikely(!page)) {
1201 ntfs_error(vol->sb, "Insufficient memory to grab "
1202 "page (index 0x%lx).", idx);
1203 return -ENOMEM;
1204 }
1205 kaddr = kmap_atomic(page, KM_USER0);
1206 memset(kaddr, val, PAGE_CACHE_SIZE);
1207 flush_dcache_page(page);
1208 kunmap_atomic(kaddr, KM_USER0);
1209 /*
1210 * If the page has buffers, mark them uptodate since buffer
1211 * state and not page state is definitive in 2.6 kernels.
1212 */
1213 if (page_has_buffers(page)) {
1214 struct buffer_head *bh, *head;
1215
1216 bh = head = page_buffers(page);
1217 do {
1218 set_buffer_uptodate(bh);
1219 } while ((bh = bh->b_this_page) != head);
1220 }
1221 /* Now that buffers are uptodate, set the page uptodate, too. */
1222 SetPageUptodate(page);
1223 /*
1224 * Set the page and all its buffers dirty and mark the inode
1225 * dirty, too. The VM will write the page later on.
1226 */
1227 set_page_dirty(page);
1228 /* Finally unlock and release the page. */
1229 unlock_page(page);
1230 page_cache_release(page);
1231 }
1232 /* If there is a last partial page, need to do it the slow way. */
1233 if (end_ofs) {
1234 page = read_cache_page(mapping, idx,
1235 (filler_t*)mapping->a_ops->readpage, NULL);
1236 if (IS_ERR(page)) {
1237 ntfs_error(vol->sb, "Failed to read last partial page "
1238 "(sync error, index 0x%lx).", idx);
1239 return PTR_ERR(page);
1240 }
1241 wait_on_page_locked(page);
1242 if (unlikely(!PageUptodate(page))) {
1243 ntfs_error(vol->sb, "Failed to read last partial page "
1244 "(async error, index 0x%lx).", idx);
1245 page_cache_release(page);
1246 return PTR_ERR(page);
1247 }
1248 kaddr = kmap_atomic(page, KM_USER0);
1249 memset(kaddr, val, end_ofs);
1250 flush_dcache_page(page);
1251 kunmap_atomic(kaddr, KM_USER0);
1252 set_page_dirty(page);
1253 page_cache_release(page);
1254 }
1255done:
1256 ntfs_debug("Done.");
1257 return 0;
1258}