[PATCH] core-dumping unreadable binaries via PT_INTERP
[linux-2.6/verdex.git] / fs / ntfs / aops.c
blob7b2c8f4f6a6f7aba6e5012f37e5e8836d0e04f0f
1 /**
2 * aops.c - NTFS kernel address space operations and page cache handling.
3 * Part of the Linux-NTFS project.
5 * Copyright (c) 2001-2006 Anton Altaparmakov
6 * Copyright (c) 2002 Richard Russon
8 * This program/include file is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as published
10 * by the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program/include file is distributed in the hope that it will be
14 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
15 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program (in the main directory of the Linux-NTFS
20 * distribution in the file COPYING); if not, write to the Free Software
21 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include <linux/errno.h>
25 #include <linux/fs.h>
26 #include <linux/mm.h>
27 #include <linux/pagemap.h>
28 #include <linux/swap.h>
29 #include <linux/buffer_head.h>
30 #include <linux/writeback.h>
31 #include <linux/bit_spinlock.h>
33 #include "aops.h"
34 #include "attrib.h"
35 #include "debug.h"
36 #include "inode.h"
37 #include "mft.h"
38 #include "runlist.h"
39 #include "types.h"
40 #include "ntfs.h"
42 /**
43 * ntfs_end_buffer_async_read - async io completion for reading attributes
44 * @bh: buffer head on which io is completed
45 * @uptodate: whether @bh is now uptodate or not
47 * Asynchronous I/O completion handler for reading pages belonging to the
48 * attribute address space of an inode. The inodes can either be files or
49 * directories or they can be fake inodes describing some attribute.
51 * If NInoMstProtected(), perform the post read mst fixups when all IO on the
52 * page has been completed and mark the page uptodate or set the error bit on
53 * the page. To determine the size of the records that need fixing up, we
54 * cheat a little bit by setting the index_block_size in ntfs_inode to the ntfs
55 * record size, and index_block_size_bits, to the log(base 2) of the ntfs
56 * record size.
58 static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
60 unsigned long flags;
61 struct buffer_head *first, *tmp;
62 struct page *page;
63 struct inode *vi;
64 ntfs_inode *ni;
65 int page_uptodate = 1;
67 page = bh->b_page;
68 vi = page->mapping->host;
69 ni = NTFS_I(vi);
71 if (likely(uptodate)) {
72 loff_t i_size;
73 s64 file_ofs, init_size;
75 set_buffer_uptodate(bh);
77 file_ofs = ((s64)page->index << PAGE_CACHE_SHIFT) +
78 bh_offset(bh);
79 read_lock_irqsave(&ni->size_lock, flags);
80 init_size = ni->initialized_size;
81 i_size = i_size_read(vi);
82 read_unlock_irqrestore(&ni->size_lock, flags);
83 if (unlikely(init_size > i_size)) {
84 /* Race with shrinking truncate. */
85 init_size = i_size;
87 /* Check for the current buffer head overflowing. */
88 if (unlikely(file_ofs + bh->b_size > init_size)) {
89 u8 *kaddr;
90 int ofs;
92 ofs = 0;
93 if (file_ofs < init_size)
94 ofs = init_size - file_ofs;
95 kaddr = kmap_atomic(page, KM_BIO_SRC_IRQ);
96 memset(kaddr + bh_offset(bh) + ofs, 0,
97 bh->b_size - ofs);
98 kunmap_atomic(kaddr, KM_BIO_SRC_IRQ);
99 flush_dcache_page(page);
101 } else {
102 clear_buffer_uptodate(bh);
103 SetPageError(page);
104 ntfs_error(ni->vol->sb, "Buffer I/O error, logical block "
105 "0x%llx.", (unsigned long long)bh->b_blocknr);
107 first = page_buffers(page);
108 local_irq_save(flags);
109 bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
110 clear_buffer_async_read(bh);
111 unlock_buffer(bh);
112 tmp = bh;
113 do {
114 if (!buffer_uptodate(tmp))
115 page_uptodate = 0;
116 if (buffer_async_read(tmp)) {
117 if (likely(buffer_locked(tmp)))
118 goto still_busy;
119 /* Async buffers must be locked. */
120 BUG();
122 tmp = tmp->b_this_page;
123 } while (tmp != bh);
124 bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
125 local_irq_restore(flags);
127 * If none of the buffers had errors then we can set the page uptodate,
128 * but we first have to perform the post read mst fixups, if the
129 * attribute is mst protected, i.e. if NInoMstProteced(ni) is true.
130 * Note we ignore fixup errors as those are detected when
131 * map_mft_record() is called which gives us per record granularity
132 * rather than per page granularity.
134 if (!NInoMstProtected(ni)) {
135 if (likely(page_uptodate && !PageError(page)))
136 SetPageUptodate(page);
137 } else {
138 u8 *kaddr;
139 unsigned int i, recs;
140 u32 rec_size;
142 rec_size = ni->itype.index.block_size;
143 recs = PAGE_CACHE_SIZE / rec_size;
144 /* Should have been verified before we got here... */
145 BUG_ON(!recs);
146 kaddr = kmap_atomic(page, KM_BIO_SRC_IRQ);
147 for (i = 0; i < recs; i++)
148 post_read_mst_fixup((NTFS_RECORD*)(kaddr +
149 i * rec_size), rec_size);
150 kunmap_atomic(kaddr, KM_BIO_SRC_IRQ);
151 flush_dcache_page(page);
152 if (likely(page_uptodate && !PageError(page)))
153 SetPageUptodate(page);
155 unlock_page(page);
156 return;
157 still_busy:
158 bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
159 local_irq_restore(flags);
160 return;
164 * ntfs_read_block - fill a @page of an address space with data
165 * @page: page cache page to fill with data
167 * Fill the page @page of the address space belonging to the @page->host inode.
168 * We read each buffer asynchronously and when all buffers are read in, our io
169 * completion handler ntfs_end_buffer_read_async(), if required, automatically
170 * applies the mst fixups to the page before finally marking it uptodate and
171 * unlocking it.
173 * We only enforce allocated_size limit because i_size is checked for in
174 * generic_file_read().
176 * Return 0 on success and -errno on error.
178 * Contains an adapted version of fs/buffer.c::block_read_full_page().
180 static int ntfs_read_block(struct page *page)
182 loff_t i_size;
183 VCN vcn;
184 LCN lcn;
185 s64 init_size;
186 struct inode *vi;
187 ntfs_inode *ni;
188 ntfs_volume *vol;
189 runlist_element *rl;
190 struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
191 sector_t iblock, lblock, zblock;
192 unsigned long flags;
193 unsigned int blocksize, vcn_ofs;
194 int i, nr;
195 unsigned char blocksize_bits;
197 vi = page->mapping->host;
198 ni = NTFS_I(vi);
199 vol = ni->vol;
201 /* $MFT/$DATA must have its complete runlist in memory at all times. */
202 BUG_ON(!ni->runlist.rl && !ni->mft_no && !NInoAttr(ni));
204 blocksize = vol->sb->s_blocksize;
205 blocksize_bits = vol->sb->s_blocksize_bits;
207 if (!page_has_buffers(page)) {
208 create_empty_buffers(page, blocksize, 0);
209 if (unlikely(!page_has_buffers(page))) {
210 unlock_page(page);
211 return -ENOMEM;
214 bh = head = page_buffers(page);
215 BUG_ON(!bh);
218 * We may be racing with truncate. To avoid some of the problems we
219 * now take a snapshot of the various sizes and use those for the whole
220 * of the function. In case of an extending truncate it just means we
221 * may leave some buffers unmapped which are now allocated. This is
222 * not a problem since these buffers will just get mapped when a write
223 * occurs. In case of a shrinking truncate, we will detect this later
224 * on due to the runlist being incomplete and if the page is being
225 * fully truncated, truncate will throw it away as soon as we unlock
226 * it so no need to worry what we do with it.
228 iblock = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
229 read_lock_irqsave(&ni->size_lock, flags);
230 lblock = (ni->allocated_size + blocksize - 1) >> blocksize_bits;
231 init_size = ni->initialized_size;
232 i_size = i_size_read(vi);
233 read_unlock_irqrestore(&ni->size_lock, flags);
234 if (unlikely(init_size > i_size)) {
235 /* Race with shrinking truncate. */
236 init_size = i_size;
238 zblock = (init_size + blocksize - 1) >> blocksize_bits;
240 /* Loop through all the buffers in the page. */
241 rl = NULL;
242 nr = i = 0;
243 do {
244 u8 *kaddr;
245 int err;
247 if (unlikely(buffer_uptodate(bh)))
248 continue;
249 if (unlikely(buffer_mapped(bh))) {
250 arr[nr++] = bh;
251 continue;
253 err = 0;
254 bh->b_bdev = vol->sb->s_bdev;
255 /* Is the block within the allowed limits? */
256 if (iblock < lblock) {
257 bool is_retry = false;
259 /* Convert iblock into corresponding vcn and offset. */
260 vcn = (VCN)iblock << blocksize_bits >>
261 vol->cluster_size_bits;
262 vcn_ofs = ((VCN)iblock << blocksize_bits) &
263 vol->cluster_size_mask;
264 if (!rl) {
265 lock_retry_remap:
266 down_read(&ni->runlist.lock);
267 rl = ni->runlist.rl;
269 if (likely(rl != NULL)) {
270 /* Seek to element containing target vcn. */
271 while (rl->length && rl[1].vcn <= vcn)
272 rl++;
273 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
274 } else
275 lcn = LCN_RL_NOT_MAPPED;
276 /* Successful remap. */
277 if (lcn >= 0) {
278 /* Setup buffer head to correct block. */
279 bh->b_blocknr = ((lcn << vol->cluster_size_bits)
280 + vcn_ofs) >> blocksize_bits;
281 set_buffer_mapped(bh);
282 /* Only read initialized data blocks. */
283 if (iblock < zblock) {
284 arr[nr++] = bh;
285 continue;
287 /* Fully non-initialized data block, zero it. */
288 goto handle_zblock;
290 /* It is a hole, need to zero it. */
291 if (lcn == LCN_HOLE)
292 goto handle_hole;
293 /* If first try and runlist unmapped, map and retry. */
294 if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
295 is_retry = true;
297 * Attempt to map runlist, dropping lock for
298 * the duration.
300 up_read(&ni->runlist.lock);
301 err = ntfs_map_runlist(ni, vcn);
302 if (likely(!err))
303 goto lock_retry_remap;
304 rl = NULL;
305 } else if (!rl)
306 up_read(&ni->runlist.lock);
308 * If buffer is outside the runlist, treat it as a
309 * hole. This can happen due to concurrent truncate
310 * for example.
312 if (err == -ENOENT || lcn == LCN_ENOENT) {
313 err = 0;
314 goto handle_hole;
316 /* Hard error, zero out region. */
317 if (!err)
318 err = -EIO;
319 bh->b_blocknr = -1;
320 SetPageError(page);
321 ntfs_error(vol->sb, "Failed to read from inode 0x%lx, "
322 "attribute type 0x%x, vcn 0x%llx, "
323 "offset 0x%x because its location on "
324 "disk could not be determined%s "
325 "(error code %i).", ni->mft_no,
326 ni->type, (unsigned long long)vcn,
327 vcn_ofs, is_retry ? " even after "
328 "retrying" : "", err);
331 * Either iblock was outside lblock limits or
332 * ntfs_rl_vcn_to_lcn() returned error. Just zero that portion
333 * of the page and set the buffer uptodate.
335 handle_hole:
336 bh->b_blocknr = -1UL;
337 clear_buffer_mapped(bh);
338 handle_zblock:
339 kaddr = kmap_atomic(page, KM_USER0);
340 memset(kaddr + i * blocksize, 0, blocksize);
341 kunmap_atomic(kaddr, KM_USER0);
342 flush_dcache_page(page);
343 if (likely(!err))
344 set_buffer_uptodate(bh);
345 } while (i++, iblock++, (bh = bh->b_this_page) != head);
347 /* Release the lock if we took it. */
348 if (rl)
349 up_read(&ni->runlist.lock);
351 /* Check we have at least one buffer ready for i/o. */
352 if (nr) {
353 struct buffer_head *tbh;
355 /* Lock the buffers. */
356 for (i = 0; i < nr; i++) {
357 tbh = arr[i];
358 lock_buffer(tbh);
359 tbh->b_end_io = ntfs_end_buffer_async_read;
360 set_buffer_async_read(tbh);
362 /* Finally, start i/o on the buffers. */
363 for (i = 0; i < nr; i++) {
364 tbh = arr[i];
365 if (likely(!buffer_uptodate(tbh)))
366 submit_bh(READ, tbh);
367 else
368 ntfs_end_buffer_async_read(tbh, 1);
370 return 0;
372 /* No i/o was scheduled on any of the buffers. */
373 if (likely(!PageError(page)))
374 SetPageUptodate(page);
375 else /* Signal synchronous i/o error. */
376 nr = -EIO;
377 unlock_page(page);
378 return nr;
382 * ntfs_readpage - fill a @page of a @file with data from the device
383 * @file: open file to which the page @page belongs or NULL
384 * @page: page cache page to fill with data
386 * For non-resident attributes, ntfs_readpage() fills the @page of the open
387 * file @file by calling the ntfs version of the generic block_read_full_page()
388 * function, ntfs_read_block(), which in turn creates and reads in the buffers
389 * associated with the page asynchronously.
391 * For resident attributes, OTOH, ntfs_readpage() fills @page by copying the
392 * data from the mft record (which at this stage is most likely in memory) and
393 * fills the remainder with zeroes. Thus, in this case, I/O is synchronous, as
394 * even if the mft record is not cached at this point in time, we need to wait
395 * for it to be read in before we can do the copy.
397 * Return 0 on success and -errno on error.
399 static int ntfs_readpage(struct file *file, struct page *page)
401 loff_t i_size;
402 struct inode *vi;
403 ntfs_inode *ni, *base_ni;
404 u8 *kaddr;
405 ntfs_attr_search_ctx *ctx;
406 MFT_RECORD *mrec;
407 unsigned long flags;
408 u32 attr_len;
409 int err = 0;
411 retry_readpage:
412 BUG_ON(!PageLocked(page));
414 * This can potentially happen because we clear PageUptodate() during
415 * ntfs_writepage() of MstProtected() attributes.
417 if (PageUptodate(page)) {
418 unlock_page(page);
419 return 0;
421 vi = page->mapping->host;
422 ni = NTFS_I(vi);
424 * Only $DATA attributes can be encrypted and only unnamed $DATA
425 * attributes can be compressed. Index root can have the flags set but
426 * this means to create compressed/encrypted files, not that the
427 * attribute is compressed/encrypted. Note we need to check for
428 * AT_INDEX_ALLOCATION since this is the type of both directory and
429 * index inodes.
431 if (ni->type != AT_INDEX_ALLOCATION) {
432 /* If attribute is encrypted, deny access, just like NT4. */
433 if (NInoEncrypted(ni)) {
434 BUG_ON(ni->type != AT_DATA);
435 err = -EACCES;
436 goto err_out;
438 /* Compressed data streams are handled in compress.c. */
439 if (NInoNonResident(ni) && NInoCompressed(ni)) {
440 BUG_ON(ni->type != AT_DATA);
441 BUG_ON(ni->name_len);
442 return ntfs_read_compressed_block(page);
445 /* NInoNonResident() == NInoIndexAllocPresent() */
446 if (NInoNonResident(ni)) {
447 /* Normal, non-resident data stream. */
448 return ntfs_read_block(page);
451 * Attribute is resident, implying it is not compressed or encrypted.
452 * This also means the attribute is smaller than an mft record and
453 * hence smaller than a page, so can simply zero out any pages with
454 * index above 0. Note the attribute can actually be marked compressed
455 * but if it is resident the actual data is not compressed so we are
456 * ok to ignore the compressed flag here.
458 if (unlikely(page->index > 0)) {
459 kaddr = kmap_atomic(page, KM_USER0);
460 memset(kaddr, 0, PAGE_CACHE_SIZE);
461 flush_dcache_page(page);
462 kunmap_atomic(kaddr, KM_USER0);
463 goto done;
465 if (!NInoAttr(ni))
466 base_ni = ni;
467 else
468 base_ni = ni->ext.base_ntfs_ino;
469 /* Map, pin, and lock the mft record. */
470 mrec = map_mft_record(base_ni);
471 if (IS_ERR(mrec)) {
472 err = PTR_ERR(mrec);
473 goto err_out;
476 * If a parallel write made the attribute non-resident, drop the mft
477 * record and retry the readpage.
479 if (unlikely(NInoNonResident(ni))) {
480 unmap_mft_record(base_ni);
481 goto retry_readpage;
483 ctx = ntfs_attr_get_search_ctx(base_ni, mrec);
484 if (unlikely(!ctx)) {
485 err = -ENOMEM;
486 goto unm_err_out;
488 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
489 CASE_SENSITIVE, 0, NULL, 0, ctx);
490 if (unlikely(err))
491 goto put_unm_err_out;
492 attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
493 read_lock_irqsave(&ni->size_lock, flags);
494 if (unlikely(attr_len > ni->initialized_size))
495 attr_len = ni->initialized_size;
496 i_size = i_size_read(vi);
497 read_unlock_irqrestore(&ni->size_lock, flags);
498 if (unlikely(attr_len > i_size)) {
499 /* Race with shrinking truncate. */
500 attr_len = i_size;
502 kaddr = kmap_atomic(page, KM_USER0);
503 /* Copy the data to the page. */
504 memcpy(kaddr, (u8*)ctx->attr +
505 le16_to_cpu(ctx->attr->data.resident.value_offset),
506 attr_len);
507 /* Zero the remainder of the page. */
508 memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
509 flush_dcache_page(page);
510 kunmap_atomic(kaddr, KM_USER0);
511 put_unm_err_out:
512 ntfs_attr_put_search_ctx(ctx);
513 unm_err_out:
514 unmap_mft_record(base_ni);
515 done:
516 SetPageUptodate(page);
517 err_out:
518 unlock_page(page);
519 return err;
522 #ifdef NTFS_RW
525 * ntfs_write_block - write a @page to the backing store
526 * @page: page cache page to write out
527 * @wbc: writeback control structure
529 * This function is for writing pages belonging to non-resident, non-mst
530 * protected attributes to their backing store.
532 * For a page with buffers, map and write the dirty buffers asynchronously
533 * under page writeback. For a page without buffers, create buffers for the
534 * page, then proceed as above.
536 * If a page doesn't have buffers the page dirty state is definitive. If a page
537 * does have buffers, the page dirty state is just a hint, and the buffer dirty
538 * state is definitive. (A hint which has rules: dirty buffers against a clean
539 * page is illegal. Other combinations are legal and need to be handled. In
540 * particular a dirty page containing clean buffers for example.)
542 * Return 0 on success and -errno on error.
544 * Based on ntfs_read_block() and __block_write_full_page().
546 static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
548 VCN vcn;
549 LCN lcn;
550 s64 initialized_size;
551 loff_t i_size;
552 sector_t block, dblock, iblock;
553 struct inode *vi;
554 ntfs_inode *ni;
555 ntfs_volume *vol;
556 runlist_element *rl;
557 struct buffer_head *bh, *head;
558 unsigned long flags;
559 unsigned int blocksize, vcn_ofs;
560 int err;
561 bool need_end_writeback;
562 unsigned char blocksize_bits;
564 vi = page->mapping->host;
565 ni = NTFS_I(vi);
566 vol = ni->vol;
568 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
569 "0x%lx.", ni->mft_no, ni->type, page->index);
571 BUG_ON(!NInoNonResident(ni));
572 BUG_ON(NInoMstProtected(ni));
573 blocksize = vol->sb->s_blocksize;
574 blocksize_bits = vol->sb->s_blocksize_bits;
575 if (!page_has_buffers(page)) {
576 BUG_ON(!PageUptodate(page));
577 create_empty_buffers(page, blocksize,
578 (1 << BH_Uptodate) | (1 << BH_Dirty));
579 if (unlikely(!page_has_buffers(page))) {
580 ntfs_warning(vol->sb, "Error allocating page "
581 "buffers. Redirtying page so we try "
582 "again later.");
584 * Put the page back on mapping->dirty_pages, but leave
585 * its buffers' dirty state as-is.
587 redirty_page_for_writepage(wbc, page);
588 unlock_page(page);
589 return 0;
592 bh = head = page_buffers(page);
593 BUG_ON(!bh);
595 /* NOTE: Different naming scheme to ntfs_read_block()! */
597 /* The first block in the page. */
598 block = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
600 read_lock_irqsave(&ni->size_lock, flags);
601 i_size = i_size_read(vi);
602 initialized_size = ni->initialized_size;
603 read_unlock_irqrestore(&ni->size_lock, flags);
605 /* The first out of bounds block for the data size. */
606 dblock = (i_size + blocksize - 1) >> blocksize_bits;
608 /* The last (fully or partially) initialized block. */
609 iblock = initialized_size >> blocksize_bits;
612 * Be very careful. We have no exclusion from __set_page_dirty_buffers
613 * here, and the (potentially unmapped) buffers may become dirty at
614 * any time. If a buffer becomes dirty here after we've inspected it
615 * then we just miss that fact, and the page stays dirty.
617 * Buffers outside i_size may be dirtied by __set_page_dirty_buffers;
618 * handle that here by just cleaning them.
622 * Loop through all the buffers in the page, mapping all the dirty
623 * buffers to disk addresses and handling any aliases from the
624 * underlying block device's mapping.
626 rl = NULL;
627 err = 0;
628 do {
629 bool is_retry = false;
631 if (unlikely(block >= dblock)) {
633 * Mapped buffers outside i_size will occur, because
634 * this page can be outside i_size when there is a
635 * truncate in progress. The contents of such buffers
636 * were zeroed by ntfs_writepage().
638 * FIXME: What about the small race window where
639 * ntfs_writepage() has not done any clearing because
640 * the page was within i_size but before we get here,
641 * vmtruncate() modifies i_size?
643 clear_buffer_dirty(bh);
644 set_buffer_uptodate(bh);
645 continue;
648 /* Clean buffers are not written out, so no need to map them. */
649 if (!buffer_dirty(bh))
650 continue;
652 /* Make sure we have enough initialized size. */
653 if (unlikely((block >= iblock) &&
654 (initialized_size < i_size))) {
656 * If this page is fully outside initialized size, zero
657 * out all pages between the current initialized size
658 * and the current page. Just use ntfs_readpage() to do
659 * the zeroing transparently.
661 if (block > iblock) {
662 // TODO:
663 // For each page do:
664 // - read_cache_page()
665 // Again for each page do:
666 // - wait_on_page_locked()
667 // - Check (PageUptodate(page) &&
668 // !PageError(page))
669 // Update initialized size in the attribute and
670 // in the inode.
671 // Again, for each page do:
672 // __set_page_dirty_buffers();
673 // page_cache_release()
674 // We don't need to wait on the writes.
675 // Update iblock.
678 * The current page straddles initialized size. Zero
679 * all non-uptodate buffers and set them uptodate (and
680 * dirty?). Note, there aren't any non-uptodate buffers
681 * if the page is uptodate.
682 * FIXME: For an uptodate page, the buffers may need to
683 * be written out because they were not initialized on
684 * disk before.
686 if (!PageUptodate(page)) {
687 // TODO:
688 // Zero any non-uptodate buffers up to i_size.
689 // Set them uptodate and dirty.
691 // TODO:
692 // Update initialized size in the attribute and in the
693 // inode (up to i_size).
694 // Update iblock.
695 // FIXME: This is inefficient. Try to batch the two
696 // size changes to happen in one go.
697 ntfs_error(vol->sb, "Writing beyond initialized size "
698 "is not supported yet. Sorry.");
699 err = -EOPNOTSUPP;
700 break;
701 // Do NOT set_buffer_new() BUT DO clear buffer range
702 // outside write request range.
703 // set_buffer_uptodate() on complete buffers as well as
704 // set_buffer_dirty().
707 /* No need to map buffers that are already mapped. */
708 if (buffer_mapped(bh))
709 continue;
711 /* Unmapped, dirty buffer. Need to map it. */
712 bh->b_bdev = vol->sb->s_bdev;
714 /* Convert block into corresponding vcn and offset. */
715 vcn = (VCN)block << blocksize_bits;
716 vcn_ofs = vcn & vol->cluster_size_mask;
717 vcn >>= vol->cluster_size_bits;
718 if (!rl) {
719 lock_retry_remap:
720 down_read(&ni->runlist.lock);
721 rl = ni->runlist.rl;
723 if (likely(rl != NULL)) {
724 /* Seek to element containing target vcn. */
725 while (rl->length && rl[1].vcn <= vcn)
726 rl++;
727 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
728 } else
729 lcn = LCN_RL_NOT_MAPPED;
730 /* Successful remap. */
731 if (lcn >= 0) {
732 /* Setup buffer head to point to correct block. */
733 bh->b_blocknr = ((lcn << vol->cluster_size_bits) +
734 vcn_ofs) >> blocksize_bits;
735 set_buffer_mapped(bh);
736 continue;
738 /* It is a hole, need to instantiate it. */
739 if (lcn == LCN_HOLE) {
740 u8 *kaddr;
741 unsigned long *bpos, *bend;
743 /* Check if the buffer is zero. */
744 kaddr = kmap_atomic(page, KM_USER0);
745 bpos = (unsigned long *)(kaddr + bh_offset(bh));
746 bend = (unsigned long *)((u8*)bpos + blocksize);
747 do {
748 if (unlikely(*bpos))
749 break;
750 } while (likely(++bpos < bend));
751 kunmap_atomic(kaddr, KM_USER0);
752 if (bpos == bend) {
754 * Buffer is zero and sparse, no need to write
755 * it.
757 bh->b_blocknr = -1;
758 clear_buffer_dirty(bh);
759 continue;
761 // TODO: Instantiate the hole.
762 // clear_buffer_new(bh);
763 // unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
764 ntfs_error(vol->sb, "Writing into sparse regions is "
765 "not supported yet. Sorry.");
766 err = -EOPNOTSUPP;
767 break;
769 /* If first try and runlist unmapped, map and retry. */
770 if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
771 is_retry = true;
773 * Attempt to map runlist, dropping lock for
774 * the duration.
776 up_read(&ni->runlist.lock);
777 err = ntfs_map_runlist(ni, vcn);
778 if (likely(!err))
779 goto lock_retry_remap;
780 rl = NULL;
781 } else if (!rl)
782 up_read(&ni->runlist.lock);
784 * If buffer is outside the runlist, truncate has cut it out
785 * of the runlist. Just clean and clear the buffer and set it
786 * uptodate so it can get discarded by the VM.
788 if (err == -ENOENT || lcn == LCN_ENOENT) {
789 u8 *kaddr;
791 bh->b_blocknr = -1;
792 clear_buffer_dirty(bh);
793 kaddr = kmap_atomic(page, KM_USER0);
794 memset(kaddr + bh_offset(bh), 0, blocksize);
795 kunmap_atomic(kaddr, KM_USER0);
796 flush_dcache_page(page);
797 set_buffer_uptodate(bh);
798 err = 0;
799 continue;
801 /* Failed to map the buffer, even after retrying. */
802 if (!err)
803 err = -EIO;
804 bh->b_blocknr = -1;
805 ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
806 "attribute type 0x%x, vcn 0x%llx, offset 0x%x "
807 "because its location on disk could not be "
808 "determined%s (error code %i).", ni->mft_no,
809 ni->type, (unsigned long long)vcn,
810 vcn_ofs, is_retry ? " even after "
811 "retrying" : "", err);
812 break;
813 } while (block++, (bh = bh->b_this_page) != head);
815 /* Release the lock if we took it. */
816 if (rl)
817 up_read(&ni->runlist.lock);
819 /* For the error case, need to reset bh to the beginning. */
820 bh = head;
822 /* Just an optimization, so ->readpage() is not called later. */
823 if (unlikely(!PageUptodate(page))) {
824 int uptodate = 1;
825 do {
826 if (!buffer_uptodate(bh)) {
827 uptodate = 0;
828 bh = head;
829 break;
831 } while ((bh = bh->b_this_page) != head);
832 if (uptodate)
833 SetPageUptodate(page);
836 /* Setup all mapped, dirty buffers for async write i/o. */
837 do {
838 if (buffer_mapped(bh) && buffer_dirty(bh)) {
839 lock_buffer(bh);
840 if (test_clear_buffer_dirty(bh)) {
841 BUG_ON(!buffer_uptodate(bh));
842 mark_buffer_async_write(bh);
843 } else
844 unlock_buffer(bh);
845 } else if (unlikely(err)) {
847 * For the error case. The buffer may have been set
848 * dirty during attachment to a dirty page.
850 if (err != -ENOMEM)
851 clear_buffer_dirty(bh);
853 } while ((bh = bh->b_this_page) != head);
855 if (unlikely(err)) {
856 // TODO: Remove the -EOPNOTSUPP check later on...
857 if (unlikely(err == -EOPNOTSUPP))
858 err = 0;
859 else if (err == -ENOMEM) {
860 ntfs_warning(vol->sb, "Error allocating memory. "
861 "Redirtying page so we try again "
862 "later.");
864 * Put the page back on mapping->dirty_pages, but
865 * leave its buffer's dirty state as-is.
867 redirty_page_for_writepage(wbc, page);
868 err = 0;
869 } else
870 SetPageError(page);
873 BUG_ON(PageWriteback(page));
874 set_page_writeback(page); /* Keeps try_to_free_buffers() away. */
876 /* Submit the prepared buffers for i/o. */
877 need_end_writeback = true;
878 do {
879 struct buffer_head *next = bh->b_this_page;
880 if (buffer_async_write(bh)) {
881 submit_bh(WRITE, bh);
882 need_end_writeback = false;
884 bh = next;
885 } while (bh != head);
886 unlock_page(page);
888 /* If no i/o was started, need to end_page_writeback(). */
889 if (unlikely(need_end_writeback))
890 end_page_writeback(page);
892 ntfs_debug("Done.");
893 return err;
897 * ntfs_write_mst_block - write a @page to the backing store
898 * @page: page cache page to write out
899 * @wbc: writeback control structure
901 * This function is for writing pages belonging to non-resident, mst protected
902 * attributes to their backing store. The only supported attributes are index
903 * allocation and $MFT/$DATA. Both directory inodes and index inodes are
904 * supported for the index allocation case.
906 * The page must remain locked for the duration of the write because we apply
907 * the mst fixups, write, and then undo the fixups, so if we were to unlock the
908 * page before undoing the fixups, any other user of the page will see the
909 * page contents as corrupt.
911 * We clear the page uptodate flag for the duration of the function to ensure
912 * exclusion for the $MFT/$DATA case against someone mapping an mft record we
913 * are about to apply the mst fixups to.
915 * Return 0 on success and -errno on error.
917 * Based on ntfs_write_block(), ntfs_mft_writepage(), and
918 * write_mft_record_nolock().
920 static int ntfs_write_mst_block(struct page *page,
921 struct writeback_control *wbc)
923 sector_t block, dblock, rec_block;
924 struct inode *vi = page->mapping->host;
925 ntfs_inode *ni = NTFS_I(vi);
926 ntfs_volume *vol = ni->vol;
927 u8 *kaddr;
928 unsigned int rec_size = ni->itype.index.block_size;
929 ntfs_inode *locked_nis[PAGE_CACHE_SIZE / rec_size];
930 struct buffer_head *bh, *head, *tbh, *rec_start_bh;
931 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
932 runlist_element *rl;
933 int i, nr_locked_nis, nr_recs, nr_bhs, max_bhs, bhs_per_rec, err, err2;
934 unsigned bh_size, rec_size_bits;
935 bool sync, is_mft, page_is_dirty, rec_is_dirty;
936 unsigned char bh_size_bits;
938 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
939 "0x%lx.", vi->i_ino, ni->type, page->index);
940 BUG_ON(!NInoNonResident(ni));
941 BUG_ON(!NInoMstProtected(ni));
942 is_mft = (S_ISREG(vi->i_mode) && !vi->i_ino);
944 * NOTE: ntfs_write_mst_block() would be called for $MFTMirr if a page
945 * in its page cache were to be marked dirty. However this should
946 * never happen with the current driver and considering we do not
947 * handle this case here we do want to BUG(), at least for now.
949 BUG_ON(!(is_mft || S_ISDIR(vi->i_mode) ||
950 (NInoAttr(ni) && ni->type == AT_INDEX_ALLOCATION)));
951 bh_size = vol->sb->s_blocksize;
952 bh_size_bits = vol->sb->s_blocksize_bits;
953 max_bhs = PAGE_CACHE_SIZE / bh_size;
954 BUG_ON(!max_bhs);
955 BUG_ON(max_bhs > MAX_BUF_PER_PAGE);
957 /* Were we called for sync purposes? */
958 sync = (wbc->sync_mode == WB_SYNC_ALL);
960 /* Make sure we have mapped buffers. */
961 bh = head = page_buffers(page);
962 BUG_ON(!bh);
964 rec_size_bits = ni->itype.index.block_size_bits;
965 BUG_ON(!(PAGE_CACHE_SIZE >> rec_size_bits));
966 bhs_per_rec = rec_size >> bh_size_bits;
967 BUG_ON(!bhs_per_rec);
969 /* The first block in the page. */
970 rec_block = block = (sector_t)page->index <<
971 (PAGE_CACHE_SHIFT - bh_size_bits);
973 /* The first out of bounds block for the data size. */
974 dblock = (i_size_read(vi) + bh_size - 1) >> bh_size_bits;
976 rl = NULL;
977 err = err2 = nr_bhs = nr_recs = nr_locked_nis = 0;
978 page_is_dirty = rec_is_dirty = false;
979 rec_start_bh = NULL;
980 do {
981 bool is_retry = false;
983 if (likely(block < rec_block)) {
984 if (unlikely(block >= dblock)) {
985 clear_buffer_dirty(bh);
986 set_buffer_uptodate(bh);
987 continue;
990 * This block is not the first one in the record. We
991 * ignore the buffer's dirty state because we could
992 * have raced with a parallel mark_ntfs_record_dirty().
994 if (!rec_is_dirty)
995 continue;
996 if (unlikely(err2)) {
997 if (err2 != -ENOMEM)
998 clear_buffer_dirty(bh);
999 continue;
1001 } else /* if (block == rec_block) */ {
1002 BUG_ON(block > rec_block);
1003 /* This block is the first one in the record. */
1004 rec_block += bhs_per_rec;
1005 err2 = 0;
1006 if (unlikely(block >= dblock)) {
1007 clear_buffer_dirty(bh);
1008 continue;
1010 if (!buffer_dirty(bh)) {
1011 /* Clean records are not written out. */
1012 rec_is_dirty = false;
1013 continue;
1015 rec_is_dirty = true;
1016 rec_start_bh = bh;
1018 /* Need to map the buffer if it is not mapped already. */
1019 if (unlikely(!buffer_mapped(bh))) {
1020 VCN vcn;
1021 LCN lcn;
1022 unsigned int vcn_ofs;
1024 bh->b_bdev = vol->sb->s_bdev;
1025 /* Obtain the vcn and offset of the current block. */
1026 vcn = (VCN)block << bh_size_bits;
1027 vcn_ofs = vcn & vol->cluster_size_mask;
1028 vcn >>= vol->cluster_size_bits;
1029 if (!rl) {
1030 lock_retry_remap:
1031 down_read(&ni->runlist.lock);
1032 rl = ni->runlist.rl;
1034 if (likely(rl != NULL)) {
1035 /* Seek to element containing target vcn. */
1036 while (rl->length && rl[1].vcn <= vcn)
1037 rl++;
1038 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
1039 } else
1040 lcn = LCN_RL_NOT_MAPPED;
1041 /* Successful remap. */
1042 if (likely(lcn >= 0)) {
1043 /* Setup buffer head to correct block. */
1044 bh->b_blocknr = ((lcn <<
1045 vol->cluster_size_bits) +
1046 vcn_ofs) >> bh_size_bits;
1047 set_buffer_mapped(bh);
1048 } else {
1050 * Remap failed. Retry to map the runlist once
1051 * unless we are working on $MFT which always
1052 * has the whole of its runlist in memory.
1054 if (!is_mft && !is_retry &&
1055 lcn == LCN_RL_NOT_MAPPED) {
1056 is_retry = true;
1058 * Attempt to map runlist, dropping
1059 * lock for the duration.
1061 up_read(&ni->runlist.lock);
1062 err2 = ntfs_map_runlist(ni, vcn);
1063 if (likely(!err2))
1064 goto lock_retry_remap;
1065 if (err2 == -ENOMEM)
1066 page_is_dirty = true;
1067 lcn = err2;
1068 } else {
1069 err2 = -EIO;
1070 if (!rl)
1071 up_read(&ni->runlist.lock);
1073 /* Hard error. Abort writing this record. */
1074 if (!err || err == -ENOMEM)
1075 err = err2;
1076 bh->b_blocknr = -1;
1077 ntfs_error(vol->sb, "Cannot write ntfs record "
1078 "0x%llx (inode 0x%lx, "
1079 "attribute type 0x%x) because "
1080 "its location on disk could "
1081 "not be determined (error "
1082 "code %lli).",
1083 (long long)block <<
1084 bh_size_bits >>
1085 vol->mft_record_size_bits,
1086 ni->mft_no, ni->type,
1087 (long long)lcn);
1089 * If this is not the first buffer, remove the
1090 * buffers in this record from the list of
1091 * buffers to write and clear their dirty bit
1092 * if not error -ENOMEM.
1094 if (rec_start_bh != bh) {
1095 while (bhs[--nr_bhs] != rec_start_bh)
1097 if (err2 != -ENOMEM) {
1098 do {
1099 clear_buffer_dirty(
1100 rec_start_bh);
1101 } while ((rec_start_bh =
1102 rec_start_bh->
1103 b_this_page) !=
1104 bh);
1107 continue;
1110 BUG_ON(!buffer_uptodate(bh));
1111 BUG_ON(nr_bhs >= max_bhs);
1112 bhs[nr_bhs++] = bh;
1113 } while (block++, (bh = bh->b_this_page) != head);
1114 if (unlikely(rl))
1115 up_read(&ni->runlist.lock);
1116 /* If there were no dirty buffers, we are done. */
1117 if (!nr_bhs)
1118 goto done;
1119 /* Map the page so we can access its contents. */
1120 kaddr = kmap(page);
1121 /* Clear the page uptodate flag whilst the mst fixups are applied. */
1122 BUG_ON(!PageUptodate(page));
1123 ClearPageUptodate(page);
1124 for (i = 0; i < nr_bhs; i++) {
1125 unsigned int ofs;
1127 /* Skip buffers which are not at the beginning of records. */
1128 if (i % bhs_per_rec)
1129 continue;
1130 tbh = bhs[i];
1131 ofs = bh_offset(tbh);
1132 if (is_mft) {
1133 ntfs_inode *tni;
1134 unsigned long mft_no;
1136 /* Get the mft record number. */
1137 mft_no = (((s64)page->index << PAGE_CACHE_SHIFT) + ofs)
1138 >> rec_size_bits;
1139 /* Check whether to write this mft record. */
1140 tni = NULL;
1141 if (!ntfs_may_write_mft_record(vol, mft_no,
1142 (MFT_RECORD*)(kaddr + ofs), &tni)) {
1144 * The record should not be written. This
1145 * means we need to redirty the page before
1146 * returning.
1148 page_is_dirty = true;
1150 * Remove the buffers in this mft record from
1151 * the list of buffers to write.
1153 do {
1154 bhs[i] = NULL;
1155 } while (++i % bhs_per_rec);
1156 continue;
1159 * The record should be written. If a locked ntfs
1160 * inode was returned, add it to the array of locked
1161 * ntfs inodes.
1163 if (tni)
1164 locked_nis[nr_locked_nis++] = tni;
1166 /* Apply the mst protection fixups. */
1167 err2 = pre_write_mst_fixup((NTFS_RECORD*)(kaddr + ofs),
1168 rec_size);
1169 if (unlikely(err2)) {
1170 if (!err || err == -ENOMEM)
1171 err = -EIO;
1172 ntfs_error(vol->sb, "Failed to apply mst fixups "
1173 "(inode 0x%lx, attribute type 0x%x, "
1174 "page index 0x%lx, page offset 0x%x)!"
1175 " Unmount and run chkdsk.", vi->i_ino,
1176 ni->type, page->index, ofs);
1178 * Mark all the buffers in this record clean as we do
1179 * not want to write corrupt data to disk.
1181 do {
1182 clear_buffer_dirty(bhs[i]);
1183 bhs[i] = NULL;
1184 } while (++i % bhs_per_rec);
1185 continue;
1187 nr_recs++;
1189 /* If no records are to be written out, we are done. */
1190 if (!nr_recs)
1191 goto unm_done;
1192 flush_dcache_page(page);
1193 /* Lock buffers and start synchronous write i/o on them. */
1194 for (i = 0; i < nr_bhs; i++) {
1195 tbh = bhs[i];
1196 if (!tbh)
1197 continue;
1198 if (unlikely(test_set_buffer_locked(tbh)))
1199 BUG();
1200 /* The buffer dirty state is now irrelevant, just clean it. */
1201 clear_buffer_dirty(tbh);
1202 BUG_ON(!buffer_uptodate(tbh));
1203 BUG_ON(!buffer_mapped(tbh));
1204 get_bh(tbh);
1205 tbh->b_end_io = end_buffer_write_sync;
1206 submit_bh(WRITE, tbh);
1208 /* Synchronize the mft mirror now if not @sync. */
1209 if (is_mft && !sync)
1210 goto do_mirror;
1211 do_wait:
1212 /* Wait on i/o completion of buffers. */
1213 for (i = 0; i < nr_bhs; i++) {
1214 tbh = bhs[i];
1215 if (!tbh)
1216 continue;
1217 wait_on_buffer(tbh);
1218 if (unlikely(!buffer_uptodate(tbh))) {
1219 ntfs_error(vol->sb, "I/O error while writing ntfs "
1220 "record buffer (inode 0x%lx, "
1221 "attribute type 0x%x, page index "
1222 "0x%lx, page offset 0x%lx)! Unmount "
1223 "and run chkdsk.", vi->i_ino, ni->type,
1224 page->index, bh_offset(tbh));
1225 if (!err || err == -ENOMEM)
1226 err = -EIO;
1228 * Set the buffer uptodate so the page and buffer
1229 * states do not become out of sync.
1231 set_buffer_uptodate(tbh);
1234 /* If @sync, now synchronize the mft mirror. */
1235 if (is_mft && sync) {
1236 do_mirror:
1237 for (i = 0; i < nr_bhs; i++) {
1238 unsigned long mft_no;
1239 unsigned int ofs;
1242 * Skip buffers which are not at the beginning of
1243 * records.
1245 if (i % bhs_per_rec)
1246 continue;
1247 tbh = bhs[i];
1248 /* Skip removed buffers (and hence records). */
1249 if (!tbh)
1250 continue;
1251 ofs = bh_offset(tbh);
1252 /* Get the mft record number. */
1253 mft_no = (((s64)page->index << PAGE_CACHE_SHIFT) + ofs)
1254 >> rec_size_bits;
1255 if (mft_no < vol->mftmirr_size)
1256 ntfs_sync_mft_mirror(vol, mft_no,
1257 (MFT_RECORD*)(kaddr + ofs),
1258 sync);
1260 if (!sync)
1261 goto do_wait;
1263 /* Remove the mst protection fixups again. */
1264 for (i = 0; i < nr_bhs; i++) {
1265 if (!(i % bhs_per_rec)) {
1266 tbh = bhs[i];
1267 if (!tbh)
1268 continue;
1269 post_write_mst_fixup((NTFS_RECORD*)(kaddr +
1270 bh_offset(tbh)));
1273 flush_dcache_page(page);
1274 unm_done:
1275 /* Unlock any locked inodes. */
1276 while (nr_locked_nis-- > 0) {
1277 ntfs_inode *tni, *base_tni;
1279 tni = locked_nis[nr_locked_nis];
1280 /* Get the base inode. */
1281 mutex_lock(&tni->extent_lock);
1282 if (tni->nr_extents >= 0)
1283 base_tni = tni;
1284 else {
1285 base_tni = tni->ext.base_ntfs_ino;
1286 BUG_ON(!base_tni);
1288 mutex_unlock(&tni->extent_lock);
1289 ntfs_debug("Unlocking %s inode 0x%lx.",
1290 tni == base_tni ? "base" : "extent",
1291 tni->mft_no);
1292 mutex_unlock(&tni->mrec_lock);
1293 atomic_dec(&tni->count);
1294 iput(VFS_I(base_tni));
1296 SetPageUptodate(page);
1297 kunmap(page);
1298 done:
1299 if (unlikely(err && err != -ENOMEM)) {
1301 * Set page error if there is only one ntfs record in the page.
1302 * Otherwise we would loose per-record granularity.
1304 if (ni->itype.index.block_size == PAGE_CACHE_SIZE)
1305 SetPageError(page);
1306 NVolSetErrors(vol);
1308 if (page_is_dirty) {
1309 ntfs_debug("Page still contains one or more dirty ntfs "
1310 "records. Redirtying the page starting at "
1311 "record 0x%lx.", page->index <<
1312 (PAGE_CACHE_SHIFT - rec_size_bits));
1313 redirty_page_for_writepage(wbc, page);
1314 unlock_page(page);
1315 } else {
1317 * Keep the VM happy. This must be done otherwise the
1318 * radix-tree tag PAGECACHE_TAG_DIRTY remains set even though
1319 * the page is clean.
1321 BUG_ON(PageWriteback(page));
1322 set_page_writeback(page);
1323 unlock_page(page);
1324 end_page_writeback(page);
1326 if (likely(!err))
1327 ntfs_debug("Done.");
1328 return err;
1332 * ntfs_writepage - write a @page to the backing store
1333 * @page: page cache page to write out
1334 * @wbc: writeback control structure
1336 * This is called from the VM when it wants to have a dirty ntfs page cache
1337 * page cleaned. The VM has already locked the page and marked it clean.
1339 * For non-resident attributes, ntfs_writepage() writes the @page by calling
1340 * the ntfs version of the generic block_write_full_page() function,
1341 * ntfs_write_block(), which in turn if necessary creates and writes the
1342 * buffers associated with the page asynchronously.
1344 * For resident attributes, OTOH, ntfs_writepage() writes the @page by copying
1345 * the data to the mft record (which at this stage is most likely in memory).
1346 * The mft record is then marked dirty and written out asynchronously via the
1347 * vfs inode dirty code path for the inode the mft record belongs to or via the
1348 * vm page dirty code path for the page the mft record is in.
1350 * Based on ntfs_readpage() and fs/buffer.c::block_write_full_page().
1352 * Return 0 on success and -errno on error.
1354 static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
1356 loff_t i_size;
1357 struct inode *vi = page->mapping->host;
1358 ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);
1359 char *kaddr;
1360 ntfs_attr_search_ctx *ctx = NULL;
1361 MFT_RECORD *m = NULL;
1362 u32 attr_len;
1363 int err;
1365 retry_writepage:
1366 BUG_ON(!PageLocked(page));
1367 i_size = i_size_read(vi);
1368 /* Is the page fully outside i_size? (truncate in progress) */
1369 if (unlikely(page->index >= (i_size + PAGE_CACHE_SIZE - 1) >>
1370 PAGE_CACHE_SHIFT)) {
1372 * The page may have dirty, unmapped buffers. Make them
1373 * freeable here, so the page does not leak.
1375 block_invalidatepage(page, 0);
1376 unlock_page(page);
1377 ntfs_debug("Write outside i_size - truncated?");
1378 return 0;
1381 * Only $DATA attributes can be encrypted and only unnamed $DATA
1382 * attributes can be compressed. Index root can have the flags set but
1383 * this means to create compressed/encrypted files, not that the
1384 * attribute is compressed/encrypted. Note we need to check for
1385 * AT_INDEX_ALLOCATION since this is the type of both directory and
1386 * index inodes.
1388 if (ni->type != AT_INDEX_ALLOCATION) {
1389 /* If file is encrypted, deny access, just like NT4. */
1390 if (NInoEncrypted(ni)) {
1391 unlock_page(page);
1392 BUG_ON(ni->type != AT_DATA);
1393 ntfs_debug("Denying write access to encrypted file.");
1394 return -EACCES;
1396 /* Compressed data streams are handled in compress.c. */
1397 if (NInoNonResident(ni) && NInoCompressed(ni)) {
1398 BUG_ON(ni->type != AT_DATA);
1399 BUG_ON(ni->name_len);
1400 // TODO: Implement and replace this with
1401 // return ntfs_write_compressed_block(page);
1402 unlock_page(page);
1403 ntfs_error(vi->i_sb, "Writing to compressed files is "
1404 "not supported yet. Sorry.");
1405 return -EOPNOTSUPP;
1407 // TODO: Implement and remove this check.
1408 if (NInoNonResident(ni) && NInoSparse(ni)) {
1409 unlock_page(page);
1410 ntfs_error(vi->i_sb, "Writing to sparse files is not "
1411 "supported yet. Sorry.");
1412 return -EOPNOTSUPP;
1415 /* NInoNonResident() == NInoIndexAllocPresent() */
1416 if (NInoNonResident(ni)) {
1417 /* We have to zero every time due to mmap-at-end-of-file. */
1418 if (page->index >= (i_size >> PAGE_CACHE_SHIFT)) {
1419 /* The page straddles i_size. */
1420 unsigned int ofs = i_size & ~PAGE_CACHE_MASK;
1421 kaddr = kmap_atomic(page, KM_USER0);
1422 memset(kaddr + ofs, 0, PAGE_CACHE_SIZE - ofs);
1423 kunmap_atomic(kaddr, KM_USER0);
1424 flush_dcache_page(page);
1426 /* Handle mst protected attributes. */
1427 if (NInoMstProtected(ni))
1428 return ntfs_write_mst_block(page, wbc);
1429 /* Normal, non-resident data stream. */
1430 return ntfs_write_block(page, wbc);
1433 * Attribute is resident, implying it is not compressed, encrypted, or
1434 * mst protected. This also means the attribute is smaller than an mft
1435 * record and hence smaller than a page, so can simply return error on
1436 * any pages with index above 0. Note the attribute can actually be
1437 * marked compressed but if it is resident the actual data is not
1438 * compressed so we are ok to ignore the compressed flag here.
1440 BUG_ON(page_has_buffers(page));
1441 BUG_ON(!PageUptodate(page));
1442 if (unlikely(page->index > 0)) {
1443 ntfs_error(vi->i_sb, "BUG()! page->index (0x%lx) > 0. "
1444 "Aborting write.", page->index);
1445 BUG_ON(PageWriteback(page));
1446 set_page_writeback(page);
1447 unlock_page(page);
1448 end_page_writeback(page);
1449 return -EIO;
1451 if (!NInoAttr(ni))
1452 base_ni = ni;
1453 else
1454 base_ni = ni->ext.base_ntfs_ino;
1455 /* Map, pin, and lock the mft record. */
1456 m = map_mft_record(base_ni);
1457 if (IS_ERR(m)) {
1458 err = PTR_ERR(m);
1459 m = NULL;
1460 ctx = NULL;
1461 goto err_out;
1464 * If a parallel write made the attribute non-resident, drop the mft
1465 * record and retry the writepage.
1467 if (unlikely(NInoNonResident(ni))) {
1468 unmap_mft_record(base_ni);
1469 goto retry_writepage;
1471 ctx = ntfs_attr_get_search_ctx(base_ni, m);
1472 if (unlikely(!ctx)) {
1473 err = -ENOMEM;
1474 goto err_out;
1476 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1477 CASE_SENSITIVE, 0, NULL, 0, ctx);
1478 if (unlikely(err))
1479 goto err_out;
1481 * Keep the VM happy. This must be done otherwise the radix-tree tag
1482 * PAGECACHE_TAG_DIRTY remains set even though the page is clean.
1484 BUG_ON(PageWriteback(page));
1485 set_page_writeback(page);
1486 unlock_page(page);
1487 attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
1488 i_size = i_size_read(vi);
1489 if (unlikely(attr_len > i_size)) {
1490 /* Race with shrinking truncate or a failed truncate. */
1491 attr_len = i_size;
1493 * If the truncate failed, fix it up now. If a concurrent
1494 * truncate, we do its job, so it does not have to do anything.
1496 err = ntfs_resident_attr_value_resize(ctx->mrec, ctx->attr,
1497 attr_len);
1498 /* Shrinking cannot fail. */
1499 BUG_ON(err);
1501 kaddr = kmap_atomic(page, KM_USER0);
1502 /* Copy the data from the page to the mft record. */
1503 memcpy((u8*)ctx->attr +
1504 le16_to_cpu(ctx->attr->data.resident.value_offset),
1505 kaddr, attr_len);
1506 /* Zero out of bounds area in the page cache page. */
1507 memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
1508 kunmap_atomic(kaddr, KM_USER0);
1509 flush_dcache_page(page);
1510 flush_dcache_mft_record_page(ctx->ntfs_ino);
1511 /* We are done with the page. */
1512 end_page_writeback(page);
1513 /* Finally, mark the mft record dirty, so it gets written back. */
1514 mark_mft_record_dirty(ctx->ntfs_ino);
1515 ntfs_attr_put_search_ctx(ctx);
1516 unmap_mft_record(base_ni);
1517 return 0;
1518 err_out:
1519 if (err == -ENOMEM) {
1520 ntfs_warning(vi->i_sb, "Error allocating memory. Redirtying "
1521 "page so we try again later.");
1523 * Put the page back on mapping->dirty_pages, but leave its
1524 * buffers' dirty state as-is.
1526 redirty_page_for_writepage(wbc, page);
1527 err = 0;
1528 } else {
1529 ntfs_error(vi->i_sb, "Resident attribute write failed with "
1530 "error %i.", err);
1531 SetPageError(page);
1532 NVolSetErrors(ni->vol);
1534 unlock_page(page);
1535 if (ctx)
1536 ntfs_attr_put_search_ctx(ctx);
1537 if (m)
1538 unmap_mft_record(base_ni);
1539 return err;
1542 #endif /* NTFS_RW */
1545 * ntfs_aops - general address space operations for inodes and attributes
1547 const struct address_space_operations ntfs_aops = {
1548 .readpage = ntfs_readpage, /* Fill page with data. */
1549 .sync_page = block_sync_page, /* Currently, just unplugs the
1550 disk request queue. */
1551 #ifdef NTFS_RW
1552 .writepage = ntfs_writepage, /* Write dirty page to disk. */
1553 #endif /* NTFS_RW */
1554 .migratepage = buffer_migrate_page, /* Move a page cache page from
1555 one physical page to an
1556 other. */
1560 * ntfs_mst_aops - general address space operations for mst protecteed inodes
1561 * and attributes
1563 const struct address_space_operations ntfs_mst_aops = {
1564 .readpage = ntfs_readpage, /* Fill page with data. */
1565 .sync_page = block_sync_page, /* Currently, just unplugs the
1566 disk request queue. */
1567 #ifdef NTFS_RW
1568 .writepage = ntfs_writepage, /* Write dirty page to disk. */
1569 .set_page_dirty = __set_page_dirty_nobuffers, /* Set the page dirty
1570 without touching the buffers
1571 belonging to the page. */
1572 #endif /* NTFS_RW */
1573 .migratepage = buffer_migrate_page, /* Move a page cache page from
1574 one physical page to an
1575 other. */
1578 #ifdef NTFS_RW
1581 * mark_ntfs_record_dirty - mark an ntfs record dirty
1582 * @page: page containing the ntfs record to mark dirty
1583 * @ofs: byte offset within @page at which the ntfs record begins
1585 * Set the buffers and the page in which the ntfs record is located dirty.
1587 * The latter also marks the vfs inode the ntfs record belongs to dirty
1588 * (I_DIRTY_PAGES only).
1590 * If the page does not have buffers, we create them and set them uptodate.
1591 * The page may not be locked which is why we need to handle the buffers under
1592 * the mapping->private_lock. Once the buffers are marked dirty we no longer
1593 * need the lock since try_to_free_buffers() does not free dirty buffers.
1595 void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) {
1596 struct address_space *mapping = page->mapping;
1597 ntfs_inode *ni = NTFS_I(mapping->host);
1598 struct buffer_head *bh, *head, *buffers_to_free = NULL;
1599 unsigned int end, bh_size, bh_ofs;
1601 BUG_ON(!PageUptodate(page));
1602 end = ofs + ni->itype.index.block_size;
1603 bh_size = VFS_I(ni)->i_sb->s_blocksize;
1604 spin_lock(&mapping->private_lock);
1605 if (unlikely(!page_has_buffers(page))) {
1606 spin_unlock(&mapping->private_lock);
1607 bh = head = alloc_page_buffers(page, bh_size, 1);
1608 spin_lock(&mapping->private_lock);
1609 if (likely(!page_has_buffers(page))) {
1610 struct buffer_head *tail;
1612 do {
1613 set_buffer_uptodate(bh);
1614 tail = bh;
1615 bh = bh->b_this_page;
1616 } while (bh);
1617 tail->b_this_page = head;
1618 attach_page_buffers(page, head);
1619 } else
1620 buffers_to_free = bh;
1622 bh = head = page_buffers(page);
1623 BUG_ON(!bh);
1624 do {
1625 bh_ofs = bh_offset(bh);
1626 if (bh_ofs + bh_size <= ofs)
1627 continue;
1628 if (unlikely(bh_ofs >= end))
1629 break;
1630 set_buffer_dirty(bh);
1631 } while ((bh = bh->b_this_page) != head);
1632 spin_unlock(&mapping->private_lock);
1633 __set_page_dirty_nobuffers(page);
1634 if (unlikely(buffers_to_free)) {
1635 do {
1636 bh = buffers_to_free->b_this_page;
1637 free_buffer_head(buffers_to_free);
1638 buffers_to_free = bh;
1639 } while (buffers_to_free);
1643 #endif /* NTFS_RW */