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1// SPDX-License-Identifier: GPL-2.0-or-later
2/**
3 * aops.c - NTFS kernel address space operations and page cache handling.
4 *
5 * Copyright (c) 2001-2014 Anton Altaparmakov and Tuxera Inc.
6 * Copyright (c) 2002 Richard Russon
7 */
8
9#include <linux/errno.h>
10#include <linux/fs.h>
11#include <linux/gfp.h>
12#include <linux/mm.h>
13#include <linux/pagemap.h>
14#include <linux/swap.h>
15#include <linux/buffer_head.h>
16#include <linux/writeback.h>
17#include <linux/bit_spinlock.h>
18#include <linux/bio.h>
19
20#include "aops.h"
21#include "attrib.h"
22#include "debug.h"
23#include "inode.h"
24#include "mft.h"
25#include "runlist.h"
26#include "types.h"
27#include "ntfs.h"
28
29/**
30 * ntfs_end_buffer_async_read - async io completion for reading attributes
31 * @bh: buffer head on which io is completed
32 * @uptodate: whether @bh is now uptodate or not
33 *
34 * Asynchronous I/O completion handler for reading pages belonging to the
35 * attribute address space of an inode. The inodes can either be files or
36 * directories or they can be fake inodes describing some attribute.
37 *
38 * If NInoMstProtected(), perform the post read mst fixups when all IO on the
39 * page has been completed and mark the page uptodate or set the error bit on
40 * the page. To determine the size of the records that need fixing up, we
41 * cheat a little bit by setting the index_block_size in ntfs_inode to the ntfs
42 * record size, and index_block_size_bits, to the log(base 2) of the ntfs
43 * record size.
44 */
45static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
46{
47 unsigned long flags;
48 struct buffer_head *first, *tmp;
49 struct page *page;
50 struct inode *vi;
51 ntfs_inode *ni;
52 int page_uptodate = 1;
53
54 page = bh->b_page;
55 vi = page->mapping->host;
56 ni = NTFS_I(vi);
57
58 if (likely(uptodate)) {
59 loff_t i_size;
60 s64 file_ofs, init_size;
61
62 set_buffer_uptodate(bh);
63
64 file_ofs = ((s64)page->index << PAGE_SHIFT) +
65 bh_offset(bh);
66 read_lock_irqsave(&ni->size_lock, flags);
67 init_size = ni->initialized_size;
68 i_size = i_size_read(vi);
69 read_unlock_irqrestore(&ni->size_lock, flags);
70 if (unlikely(init_size > i_size)) {
71 /* Race with shrinking truncate. */
72 init_size = i_size;
73 }
74 /* Check for the current buffer head overflowing. */
75 if (unlikely(file_ofs + bh->b_size > init_size)) {
76 int ofs;
77 void *kaddr;
78
79 ofs = 0;
80 if (file_ofs < init_size)
81 ofs = init_size - file_ofs;
82 kaddr = kmap_atomic(page);
83 memset(kaddr + bh_offset(bh) + ofs, 0,
84 bh->b_size - ofs);
85 flush_dcache_page(page);
86 kunmap_atomic(kaddr);
87 }
88 } else {
89 clear_buffer_uptodate(bh);
90 SetPageError(page);
91 ntfs_error(ni->vol->sb, "Buffer I/O error, logical block "
92 "0x%llx.", (unsigned long long)bh->b_blocknr);
93 }
94 first = page_buffers(page);
95 spin_lock_irqsave(&first->b_uptodate_lock, flags);
96 clear_buffer_async_read(bh);
97 unlock_buffer(bh);
98 tmp = bh;
99 do {
100 if (!buffer_uptodate(tmp))
101 page_uptodate = 0;
102 if (buffer_async_read(tmp)) {
103 if (likely(buffer_locked(tmp)))
104 goto still_busy;
105 /* Async buffers must be locked. */
106 BUG();
107 }
108 tmp = tmp->b_this_page;
109 } while (tmp != bh);
110 spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
111 /*
112 * If none of the buffers had errors then we can set the page uptodate,
113 * but we first have to perform the post read mst fixups, if the
114 * attribute is mst protected, i.e. if NInoMstProteced(ni) is true.
115 * Note we ignore fixup errors as those are detected when
116 * map_mft_record() is called which gives us per record granularity
117 * rather than per page granularity.
118 */
119 if (!NInoMstProtected(ni)) {
120 if (likely(page_uptodate && !PageError(page)))
121 SetPageUptodate(page);
122 } else {
123 u8 *kaddr;
124 unsigned int i, recs;
125 u32 rec_size;
126
127 rec_size = ni->itype.index.block_size;
128 recs = PAGE_SIZE / rec_size;
129 /* Should have been verified before we got here... */
130 BUG_ON(!recs);
131 kaddr = kmap_atomic(page);
132 for (i = 0; i < recs; i++)
133 post_read_mst_fixup((NTFS_RECORD*)(kaddr +
134 i * rec_size), rec_size);
135 kunmap_atomic(kaddr);
136 flush_dcache_page(page);
137 if (likely(page_uptodate && !PageError(page)))
138 SetPageUptodate(page);
139 }
140 unlock_page(page);
141 return;
142still_busy:
143 spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
144 return;
145}
146
147/**
148 * ntfs_read_block - fill a @page of an address space with data
149 * @page: page cache page to fill with data
150 *
151 * Fill the page @page of the address space belonging to the @page->host inode.
152 * We read each buffer asynchronously and when all buffers are read in, our io
153 * completion handler ntfs_end_buffer_read_async(), if required, automatically
154 * applies the mst fixups to the page before finally marking it uptodate and
155 * unlocking it.
156 *
157 * We only enforce allocated_size limit because i_size is checked for in
158 * generic_file_read().
159 *
160 * Return 0 on success and -errno on error.
161 *
162 * Contains an adapted version of fs/buffer.c::block_read_full_page().
163 */
164static int ntfs_read_block(struct page *page)
165{
166 loff_t i_size;
167 VCN vcn;
168 LCN lcn;
169 s64 init_size;
170 struct inode *vi;
171 ntfs_inode *ni;
172 ntfs_volume *vol;
173 runlist_element *rl;
174 struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
175 sector_t iblock, lblock, zblock;
176 unsigned long flags;
177 unsigned int blocksize, vcn_ofs;
178 int i, nr;
179 unsigned char blocksize_bits;
180
181 vi = page->mapping->host;
182 ni = NTFS_I(vi);
183 vol = ni->vol;
184
185 /* $MFT/$DATA must have its complete runlist in memory at all times. */
186 BUG_ON(!ni->runlist.rl && !ni->mft_no && !NInoAttr(ni));
187
188 blocksize = vol->sb->s_blocksize;
189 blocksize_bits = vol->sb->s_blocksize_bits;
190
191 if (!page_has_buffers(page)) {
192 create_empty_buffers(page, blocksize, 0);
193 if (unlikely(!page_has_buffers(page))) {
194 unlock_page(page);
195 return -ENOMEM;
196 }
197 }
198 bh = head = page_buffers(page);
199 BUG_ON(!bh);
200
201 /*
202 * We may be racing with truncate. To avoid some of the problems we
203 * now take a snapshot of the various sizes and use those for the whole
204 * of the function. In case of an extending truncate it just means we
205 * may leave some buffers unmapped which are now allocated. This is
206 * not a problem since these buffers will just get mapped when a write
207 * occurs. In case of a shrinking truncate, we will detect this later
208 * on due to the runlist being incomplete and if the page is being
209 * fully truncated, truncate will throw it away as soon as we unlock
210 * it so no need to worry what we do with it.
211 */
212 iblock = (s64)page->index << (PAGE_SHIFT - blocksize_bits);
213 read_lock_irqsave(&ni->size_lock, flags);
214 lblock = (ni->allocated_size + blocksize - 1) >> blocksize_bits;
215 init_size = ni->initialized_size;
216 i_size = i_size_read(vi);
217 read_unlock_irqrestore(&ni->size_lock, flags);
218 if (unlikely(init_size > i_size)) {
219 /* Race with shrinking truncate. */
220 init_size = i_size;
221 }
222 zblock = (init_size + blocksize - 1) >> blocksize_bits;
223
224 /* Loop through all the buffers in the page. */
225 rl = NULL;
226 nr = i = 0;
227 do {
228 int err = 0;
229
230 if (unlikely(buffer_uptodate(bh)))
231 continue;
232 if (unlikely(buffer_mapped(bh))) {
233 arr[nr++] = bh;
234 continue;
235 }
236 bh->b_bdev = vol->sb->s_bdev;
237 /* Is the block within the allowed limits? */
238 if (iblock < lblock) {
239 bool is_retry = false;
240
241 /* Convert iblock into corresponding vcn and offset. */
242 vcn = (VCN)iblock << blocksize_bits >>
243 vol->cluster_size_bits;
244 vcn_ofs = ((VCN)iblock << blocksize_bits) &
245 vol->cluster_size_mask;
246 if (!rl) {
247lock_retry_remap:
248 down_read(&ni->runlist.lock);
249 rl = ni->runlist.rl;
250 }
251 if (likely(rl != NULL)) {
252 /* Seek to element containing target vcn. */
253 while (rl->length && rl[1].vcn <= vcn)
254 rl++;
255 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
256 } else
257 lcn = LCN_RL_NOT_MAPPED;
258 /* Successful remap. */
259 if (lcn >= 0) {
260 /* Setup buffer head to correct block. */
261 bh->b_blocknr = ((lcn << vol->cluster_size_bits)
262 + vcn_ofs) >> blocksize_bits;
263 set_buffer_mapped(bh);
264 /* Only read initialized data blocks. */
265 if (iblock < zblock) {
266 arr[nr++] = bh;
267 continue;
268 }
269 /* Fully non-initialized data block, zero it. */
270 goto handle_zblock;
271 }
272 /* It is a hole, need to zero it. */
273 if (lcn == LCN_HOLE)
274 goto handle_hole;
275 /* If first try and runlist unmapped, map and retry. */
276 if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
277 is_retry = true;
278 /*
279 * Attempt to map runlist, dropping lock for
280 * the duration.
281 */
282 up_read(&ni->runlist.lock);
283 err = ntfs_map_runlist(ni, vcn);
284 if (likely(!err))
285 goto lock_retry_remap;
286 rl = NULL;
287 } else if (!rl)
288 up_read(&ni->runlist.lock);
289 /*
290 * If buffer is outside the runlist, treat it as a
291 * hole. This can happen due to concurrent truncate
292 * for example.
293 */
294 if (err == -ENOENT || lcn == LCN_ENOENT) {
295 err = 0;
296 goto handle_hole;
297 }
298 /* Hard error, zero out region. */
299 if (!err)
300 err = -EIO;
301 bh->b_blocknr = -1;
302 SetPageError(page);
303 ntfs_error(vol->sb, "Failed to read from inode 0x%lx, "
304 "attribute type 0x%x, vcn 0x%llx, "
305 "offset 0x%x because its location on "
306 "disk could not be determined%s "
307 "(error code %i).", ni->mft_no,
308 ni->type, (unsigned long long)vcn,
309 vcn_ofs, is_retry ? " even after "
310 "retrying" : "", err);
311 }
312 /*
313 * Either iblock was outside lblock limits or
314 * ntfs_rl_vcn_to_lcn() returned error. Just zero that portion
315 * of the page and set the buffer uptodate.
316 */
317handle_hole:
318 bh->b_blocknr = -1UL;
319 clear_buffer_mapped(bh);
320handle_zblock:
321 zero_user(page, i * blocksize, blocksize);
322 if (likely(!err))
323 set_buffer_uptodate(bh);
324 } while (i++, iblock++, (bh = bh->b_this_page) != head);
325
326 /* Release the lock if we took it. */
327 if (rl)
328 up_read(&ni->runlist.lock);
329
330 /* Check we have at least one buffer ready for i/o. */
331 if (nr) {
332 struct buffer_head *tbh;
333
334 /* Lock the buffers. */
335 for (i = 0; i < nr; i++) {
336 tbh = arr[i];
337 lock_buffer(tbh);
338 tbh->b_end_io = ntfs_end_buffer_async_read;
339 set_buffer_async_read(tbh);
340 }
341 /* Finally, start i/o on the buffers. */
342 for (i = 0; i < nr; i++) {
343 tbh = arr[i];
344 if (likely(!buffer_uptodate(tbh)))
345 submit_bh(REQ_OP_READ, 0, tbh);
346 else
347 ntfs_end_buffer_async_read(tbh, 1);
348 }
349 return 0;
350 }
351 /* No i/o was scheduled on any of the buffers. */
352 if (likely(!PageError(page)))
353 SetPageUptodate(page);
354 else /* Signal synchronous i/o error. */
355 nr = -EIO;
356 unlock_page(page);
357 return nr;
358}
359
360/**
361 * ntfs_readpage - fill a @page of a @file with data from the device
362 * @file: open file to which the page @page belongs or NULL
363 * @page: page cache page to fill with data
364 *
365 * For non-resident attributes, ntfs_readpage() fills the @page of the open
366 * file @file by calling the ntfs version of the generic block_read_full_page()
367 * function, ntfs_read_block(), which in turn creates and reads in the buffers
368 * associated with the page asynchronously.
369 *
370 * For resident attributes, OTOH, ntfs_readpage() fills @page by copying the
371 * data from the mft record (which at this stage is most likely in memory) and
372 * fills the remainder with zeroes. Thus, in this case, I/O is synchronous, as
373 * even if the mft record is not cached at this point in time, we need to wait
374 * for it to be read in before we can do the copy.
375 *
376 * Return 0 on success and -errno on error.
377 */
378static int ntfs_readpage(struct file *file, struct page *page)
379{
380 loff_t i_size;
381 struct inode *vi;
382 ntfs_inode *ni, *base_ni;
383 u8 *addr;
384 ntfs_attr_search_ctx *ctx;
385 MFT_RECORD *mrec;
386 unsigned long flags;
387 u32 attr_len;
388 int err = 0;
389
390retry_readpage:
391 BUG_ON(!PageLocked(page));
392 vi = page->mapping->host;
393 i_size = i_size_read(vi);
394 /* Is the page fully outside i_size? (truncate in progress) */
395 if (unlikely(page->index >= (i_size + PAGE_SIZE - 1) >>
396 PAGE_SHIFT)) {
397 zero_user(page, 0, PAGE_SIZE);
398 ntfs_debug("Read outside i_size - truncated?");
399 goto done;
400 }
401 /*
402 * This can potentially happen because we clear PageUptodate() during
403 * ntfs_writepage() of MstProtected() attributes.
404 */
405 if (PageUptodate(page)) {
406 unlock_page(page);
407 return 0;
408 }
409 ni = NTFS_I(vi);
410 /*
411 * Only $DATA attributes can be encrypted and only unnamed $DATA
412 * attributes can be compressed. Index root can have the flags set but
413 * this means to create compressed/encrypted files, not that the
414 * attribute is compressed/encrypted. Note we need to check for
415 * AT_INDEX_ALLOCATION since this is the type of both directory and
416 * index inodes.
417 */
418 if (ni->type != AT_INDEX_ALLOCATION) {
419 /* If attribute is encrypted, deny access, just like NT4. */
420 if (NInoEncrypted(ni)) {
421 BUG_ON(ni->type != AT_DATA);
422 err = -EACCES;
423 goto err_out;
424 }
425 /* Compressed data streams are handled in compress.c. */
426 if (NInoNonResident(ni) && NInoCompressed(ni)) {
427 BUG_ON(ni->type != AT_DATA);
428 BUG_ON(ni->name_len);
429 return ntfs_read_compressed_block(page);
430 }
431 }
432 /* NInoNonResident() == NInoIndexAllocPresent() */
433 if (NInoNonResident(ni)) {
434 /* Normal, non-resident data stream. */
435 return ntfs_read_block(page);
436 }
437 /*
438 * Attribute is resident, implying it is not compressed or encrypted.
439 * This also means the attribute is smaller than an mft record and
440 * hence smaller than a page, so can simply zero out any pages with
441 * index above 0. Note the attribute can actually be marked compressed
442 * but if it is resident the actual data is not compressed so we are
443 * ok to ignore the compressed flag here.
444 */
445 if (unlikely(page->index > 0)) {
446 zero_user(page, 0, PAGE_SIZE);
447 goto done;
448 }
449 if (!NInoAttr(ni))
450 base_ni = ni;
451 else
452 base_ni = ni->ext.base_ntfs_ino;
453 /* Map, pin, and lock the mft record. */
454 mrec = map_mft_record(base_ni);
455 if (IS_ERR(mrec)) {
456 err = PTR_ERR(mrec);
457 goto err_out;
458 }
459 /*
460 * If a parallel write made the attribute non-resident, drop the mft
461 * record and retry the readpage.
462 */
463 if (unlikely(NInoNonResident(ni))) {
464 unmap_mft_record(base_ni);
465 goto retry_readpage;
466 }
467 ctx = ntfs_attr_get_search_ctx(base_ni, mrec);
468 if (unlikely(!ctx)) {
469 err = -ENOMEM;
470 goto unm_err_out;
471 }
472 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
473 CASE_SENSITIVE, 0, NULL, 0, ctx);
474 if (unlikely(err))
475 goto put_unm_err_out;
476 attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
477 read_lock_irqsave(&ni->size_lock, flags);
478 if (unlikely(attr_len > ni->initialized_size))
479 attr_len = ni->initialized_size;
480 i_size = i_size_read(vi);
481 read_unlock_irqrestore(&ni->size_lock, flags);
482 if (unlikely(attr_len > i_size)) {
483 /* Race with shrinking truncate. */
484 attr_len = i_size;
485 }
486 addr = kmap_atomic(page);
487 /* Copy the data to the page. */
488 memcpy(addr, (u8*)ctx->attr +
489 le16_to_cpu(ctx->attr->data.resident.value_offset),
490 attr_len);
491 /* Zero the remainder of the page. */
492 memset(addr + attr_len, 0, PAGE_SIZE - attr_len);
493 flush_dcache_page(page);
494 kunmap_atomic(addr);
495put_unm_err_out:
496 ntfs_attr_put_search_ctx(ctx);
497unm_err_out:
498 unmap_mft_record(base_ni);
499done:
500 SetPageUptodate(page);
501err_out:
502 unlock_page(page);
503 return err;
504}
505
506#ifdef NTFS_RW
507
508/**
509 * ntfs_write_block - write a @page to the backing store
510 * @page: page cache page to write out
511 * @wbc: writeback control structure
512 *
513 * This function is for writing pages belonging to non-resident, non-mst
514 * protected attributes to their backing store.
515 *
516 * For a page with buffers, map and write the dirty buffers asynchronously
517 * under page writeback. For a page without buffers, create buffers for the
518 * page, then proceed as above.
519 *
520 * If a page doesn't have buffers the page dirty state is definitive. If a page
521 * does have buffers, the page dirty state is just a hint, and the buffer dirty
522 * state is definitive. (A hint which has rules: dirty buffers against a clean
523 * page is illegal. Other combinations are legal and need to be handled. In
524 * particular a dirty page containing clean buffers for example.)
525 *
526 * Return 0 on success and -errno on error.
527 *
528 * Based on ntfs_read_block() and __block_write_full_page().
529 */
530static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
531{
532 VCN vcn;
533 LCN lcn;
534 s64 initialized_size;
535 loff_t i_size;
536 sector_t block, dblock, iblock;
537 struct inode *vi;
538 ntfs_inode *ni;
539 ntfs_volume *vol;
540 runlist_element *rl;
541 struct buffer_head *bh, *head;
542 unsigned long flags;
543 unsigned int blocksize, vcn_ofs;
544 int err;
545 bool need_end_writeback;
546 unsigned char blocksize_bits;
547
548 vi = page->mapping->host;
549 ni = NTFS_I(vi);
550 vol = ni->vol;
551
552 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
553 "0x%lx.", ni->mft_no, ni->type, page->index);
554
555 BUG_ON(!NInoNonResident(ni));
556 BUG_ON(NInoMstProtected(ni));
557 blocksize = vol->sb->s_blocksize;
558 blocksize_bits = vol->sb->s_blocksize_bits;
559 if (!page_has_buffers(page)) {
560 BUG_ON(!PageUptodate(page));
561 create_empty_buffers(page, blocksize,
562 (1 << BH_Uptodate) | (1 << BH_Dirty));
563 if (unlikely(!page_has_buffers(page))) {
564 ntfs_warning(vol->sb, "Error allocating page "
565 "buffers. Redirtying page so we try "
566 "again later.");
567 /*
568 * Put the page back on mapping->dirty_pages, but leave
569 * its buffers' dirty state as-is.
570 */
571 redirty_page_for_writepage(wbc, page);
572 unlock_page(page);
573 return 0;
574 }
575 }
576 bh = head = page_buffers(page);
577 BUG_ON(!bh);
578
579 /* NOTE: Different naming scheme to ntfs_read_block()! */
580
581 /* The first block in the page. */
582 block = (s64)page->index << (PAGE_SHIFT - blocksize_bits);
583
584 read_lock_irqsave(&ni->size_lock, flags);
585 i_size = i_size_read(vi);
586 initialized_size = ni->initialized_size;
587 read_unlock_irqrestore(&ni->size_lock, flags);
588
589 /* The first out of bounds block for the data size. */
590 dblock = (i_size + blocksize - 1) >> blocksize_bits;
591
592 /* The last (fully or partially) initialized block. */
593 iblock = initialized_size >> blocksize_bits;
594
595 /*
596 * Be very careful. We have no exclusion from __set_page_dirty_buffers
597 * here, and the (potentially unmapped) buffers may become dirty at
598 * any time. If a buffer becomes dirty here after we've inspected it
599 * then we just miss that fact, and the page stays dirty.
600 *
601 * Buffers outside i_size may be dirtied by __set_page_dirty_buffers;
602 * handle that here by just cleaning them.
603 */
604
605 /*
606 * Loop through all the buffers in the page, mapping all the dirty
607 * buffers to disk addresses and handling any aliases from the
608 * underlying block device's mapping.
609 */
610 rl = NULL;
611 err = 0;
612 do {
613 bool is_retry = false;
614
615 if (unlikely(block >= dblock)) {
616 /*
617 * Mapped buffers outside i_size will occur, because
618 * this page can be outside i_size when there is a
619 * truncate in progress. The contents of such buffers
620 * were zeroed by ntfs_writepage().
621 *
622 * FIXME: What about the small race window where
623 * ntfs_writepage() has not done any clearing because
624 * the page was within i_size but before we get here,
625 * vmtruncate() modifies i_size?
626 */
627 clear_buffer_dirty(bh);
628 set_buffer_uptodate(bh);
629 continue;
630 }
631
632 /* Clean buffers are not written out, so no need to map them. */
633 if (!buffer_dirty(bh))
634 continue;
635
636 /* Make sure we have enough initialized size. */
637 if (unlikely((block >= iblock) &&
638 (initialized_size < i_size))) {
639 /*
640 * If this page is fully outside initialized size, zero
641 * out all pages between the current initialized size
642 * and the current page. Just use ntfs_readpage() to do
643 * the zeroing transparently.
644 */
645 if (block > iblock) {
646 // TODO:
647 // For each page do:
648 // - read_cache_page()
649 // Again for each page do:
650 // - wait_on_page_locked()
651 // - Check (PageUptodate(page) &&
652 // !PageError(page))
653 // Update initialized size in the attribute and
654 // in the inode.
655 // Again, for each page do:
656 // __set_page_dirty_buffers();
657 // put_page()
658 // We don't need to wait on the writes.
659 // Update iblock.
660 }
661 /*
662 * The current page straddles initialized size. Zero
663 * all non-uptodate buffers and set them uptodate (and
664 * dirty?). Note, there aren't any non-uptodate buffers
665 * if the page is uptodate.
666 * FIXME: For an uptodate page, the buffers may need to
667 * be written out because they were not initialized on
668 * disk before.
669 */
670 if (!PageUptodate(page)) {
671 // TODO:
672 // Zero any non-uptodate buffers up to i_size.
673 // Set them uptodate and dirty.
674 }
675 // TODO:
676 // Update initialized size in the attribute and in the
677 // inode (up to i_size).
678 // Update iblock.
679 // FIXME: This is inefficient. Try to batch the two
680 // size changes to happen in one go.
681 ntfs_error(vol->sb, "Writing beyond initialized size "
682 "is not supported yet. Sorry.");
683 err = -EOPNOTSUPP;
684 break;
685 // Do NOT set_buffer_new() BUT DO clear buffer range
686 // outside write request range.
687 // set_buffer_uptodate() on complete buffers as well as
688 // set_buffer_dirty().
689 }
690
691 /* No need to map buffers that are already mapped. */
692 if (buffer_mapped(bh))
693 continue;
694
695 /* Unmapped, dirty buffer. Need to map it. */
696 bh->b_bdev = vol->sb->s_bdev;
697
698 /* Convert block into corresponding vcn and offset. */
699 vcn = (VCN)block << blocksize_bits;
700 vcn_ofs = vcn & vol->cluster_size_mask;
701 vcn >>= vol->cluster_size_bits;
702 if (!rl) {
703lock_retry_remap:
704 down_read(&ni->runlist.lock);
705 rl = ni->runlist.rl;
706 }
707 if (likely(rl != NULL)) {
708 /* Seek to element containing target vcn. */
709 while (rl->length && rl[1].vcn <= vcn)
710 rl++;
711 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
712 } else
713 lcn = LCN_RL_NOT_MAPPED;
714 /* Successful remap. */
715 if (lcn >= 0) {
716 /* Setup buffer head to point to correct block. */
717 bh->b_blocknr = ((lcn << vol->cluster_size_bits) +
718 vcn_ofs) >> blocksize_bits;
719 set_buffer_mapped(bh);
720 continue;
721 }
722 /* It is a hole, need to instantiate it. */
723 if (lcn == LCN_HOLE) {
724 u8 *kaddr;
725 unsigned long *bpos, *bend;
726
727 /* Check if the buffer is zero. */
728 kaddr = kmap_atomic(page);
729 bpos = (unsigned long *)(kaddr + bh_offset(bh));
730 bend = (unsigned long *)((u8*)bpos + blocksize);
731 do {
732 if (unlikely(*bpos))
733 break;
734 } while (likely(++bpos < bend));
735 kunmap_atomic(kaddr);
736 if (bpos == bend) {
737 /*
738 * Buffer is zero and sparse, no need to write
739 * it.
740 */
741 bh->b_blocknr = -1;
742 clear_buffer_dirty(bh);
743 continue;
744 }
745 // TODO: Instantiate the hole.
746 // clear_buffer_new(bh);
747 // clean_bdev_bh_alias(bh);
748 ntfs_error(vol->sb, "Writing into sparse regions is "
749 "not supported yet. Sorry.");
750 err = -EOPNOTSUPP;
751 break;
752 }
753 /* If first try and runlist unmapped, map and retry. */
754 if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
755 is_retry = true;
756 /*
757 * Attempt to map runlist, dropping lock for
758 * the duration.
759 */
760 up_read(&ni->runlist.lock);
761 err = ntfs_map_runlist(ni, vcn);
762 if (likely(!err))
763 goto lock_retry_remap;
764 rl = NULL;
765 } else if (!rl)
766 up_read(&ni->runlist.lock);
767 /*
768 * If buffer is outside the runlist, truncate has cut it out
769 * of the runlist. Just clean and clear the buffer and set it
770 * uptodate so it can get discarded by the VM.
771 */
772 if (err == -ENOENT || lcn == LCN_ENOENT) {
773 bh->b_blocknr = -1;
774 clear_buffer_dirty(bh);
775 zero_user(page, bh_offset(bh), blocksize);
776 set_buffer_uptodate(bh);
777 err = 0;
778 continue;
779 }
780 /* Failed to map the buffer, even after retrying. */
781 if (!err)
782 err = -EIO;
783 bh->b_blocknr = -1;
784 ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
785 "attribute type 0x%x, vcn 0x%llx, offset 0x%x "
786 "because its location on disk could not be "
787 "determined%s (error code %i).", ni->mft_no,
788 ni->type, (unsigned long long)vcn,
789 vcn_ofs, is_retry ? " even after "
790 "retrying" : "", err);
791 break;
792 } while (block++, (bh = bh->b_this_page) != head);
793
794 /* Release the lock if we took it. */
795 if (rl)
796 up_read(&ni->runlist.lock);
797
798 /* For the error case, need to reset bh to the beginning. */
799 bh = head;
800
801 /* Just an optimization, so ->readpage() is not called later. */
802 if (unlikely(!PageUptodate(page))) {
803 int uptodate = 1;
804 do {
805 if (!buffer_uptodate(bh)) {
806 uptodate = 0;
807 bh = head;
808 break;
809 }
810 } while ((bh = bh->b_this_page) != head);
811 if (uptodate)
812 SetPageUptodate(page);
813 }
814
815 /* Setup all mapped, dirty buffers for async write i/o. */
816 do {
817 if (buffer_mapped(bh) && buffer_dirty(bh)) {
818 lock_buffer(bh);
819 if (test_clear_buffer_dirty(bh)) {
820 BUG_ON(!buffer_uptodate(bh));
821 mark_buffer_async_write(bh);
822 } else
823 unlock_buffer(bh);
824 } else if (unlikely(err)) {
825 /*
826 * For the error case. The buffer may have been set
827 * dirty during attachment to a dirty page.
828 */
829 if (err != -ENOMEM)
830 clear_buffer_dirty(bh);
831 }
832 } while ((bh = bh->b_this_page) != head);
833
834 if (unlikely(err)) {
835 // TODO: Remove the -EOPNOTSUPP check later on...
836 if (unlikely(err == -EOPNOTSUPP))
837 err = 0;
838 else if (err == -ENOMEM) {
839 ntfs_warning(vol->sb, "Error allocating memory. "
840 "Redirtying page so we try again "
841 "later.");
842 /*
843 * Put the page back on mapping->dirty_pages, but
844 * leave its buffer's dirty state as-is.
845 */
846 redirty_page_for_writepage(wbc, page);
847 err = 0;
848 } else
849 SetPageError(page);
850 }
851
852 BUG_ON(PageWriteback(page));
853 set_page_writeback(page); /* Keeps try_to_free_buffers() away. */
854
855 /* Submit the prepared buffers for i/o. */
856 need_end_writeback = true;
857 do {
858 struct buffer_head *next = bh->b_this_page;
859 if (buffer_async_write(bh)) {
860 submit_bh(REQ_OP_WRITE, 0, bh);
861 need_end_writeback = false;
862 }
863 bh = next;
864 } while (bh != head);
865 unlock_page(page);
866
867 /* If no i/o was started, need to end_page_writeback(). */
868 if (unlikely(need_end_writeback))
869 end_page_writeback(page);
870
871 ntfs_debug("Done.");
872 return err;
873}
874
875/**
876 * ntfs_write_mst_block - write a @page to the backing store
877 * @page: page cache page to write out
878 * @wbc: writeback control structure
879 *
880 * This function is for writing pages belonging to non-resident, mst protected
881 * attributes to their backing store. The only supported attributes are index
882 * allocation and $MFT/$DATA. Both directory inodes and index inodes are
883 * supported for the index allocation case.
884 *
885 * The page must remain locked for the duration of the write because we apply
886 * the mst fixups, write, and then undo the fixups, so if we were to unlock the
887 * page before undoing the fixups, any other user of the page will see the
888 * page contents as corrupt.
889 *
890 * We clear the page uptodate flag for the duration of the function to ensure
891 * exclusion for the $MFT/$DATA case against someone mapping an mft record we
892 * are about to apply the mst fixups to.
893 *
894 * Return 0 on success and -errno on error.
895 *
896 * Based on ntfs_write_block(), ntfs_mft_writepage(), and
897 * write_mft_record_nolock().
898 */
899static int ntfs_write_mst_block(struct page *page,
900 struct writeback_control *wbc)
901{
902 sector_t block, dblock, rec_block;
903 struct inode *vi = page->mapping->host;
904 ntfs_inode *ni = NTFS_I(vi);
905 ntfs_volume *vol = ni->vol;
906 u8 *kaddr;
907 unsigned int rec_size = ni->itype.index.block_size;
908 ntfs_inode *locked_nis[PAGE_SIZE / NTFS_BLOCK_SIZE];
909 struct buffer_head *bh, *head, *tbh, *rec_start_bh;
910 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
911 runlist_element *rl;
912 int i, nr_locked_nis, nr_recs, nr_bhs, max_bhs, bhs_per_rec, err, err2;
913 unsigned bh_size, rec_size_bits;
914 bool sync, is_mft, page_is_dirty, rec_is_dirty;
915 unsigned char bh_size_bits;
916
917 if (WARN_ON(rec_size < NTFS_BLOCK_SIZE))
918 return -EINVAL;
919
920 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
921 "0x%lx.", vi->i_ino, ni->type, page->index);
922 BUG_ON(!NInoNonResident(ni));
923 BUG_ON(!NInoMstProtected(ni));
924 is_mft = (S_ISREG(vi->i_mode) && !vi->i_ino);
925 /*
926 * NOTE: ntfs_write_mst_block() would be called for $MFTMirr if a page
927 * in its page cache were to be marked dirty. However this should
928 * never happen with the current driver and considering we do not
929 * handle this case here we do want to BUG(), at least for now.
930 */
931 BUG_ON(!(is_mft || S_ISDIR(vi->i_mode) ||
932 (NInoAttr(ni) && ni->type == AT_INDEX_ALLOCATION)));
933 bh_size = vol->sb->s_blocksize;
934 bh_size_bits = vol->sb->s_blocksize_bits;
935 max_bhs = PAGE_SIZE / bh_size;
936 BUG_ON(!max_bhs);
937 BUG_ON(max_bhs > MAX_BUF_PER_PAGE);
938
939 /* Were we called for sync purposes? */
940 sync = (wbc->sync_mode == WB_SYNC_ALL);
941
942 /* Make sure we have mapped buffers. */
943 bh = head = page_buffers(page);
944 BUG_ON(!bh);
945
946 rec_size_bits = ni->itype.index.block_size_bits;
947 BUG_ON(!(PAGE_SIZE >> rec_size_bits));
948 bhs_per_rec = rec_size >> bh_size_bits;
949 BUG_ON(!bhs_per_rec);
950
951 /* The first block in the page. */
952 rec_block = block = (sector_t)page->index <<
953 (PAGE_SHIFT - bh_size_bits);
954
955 /* The first out of bounds block for the data size. */
956 dblock = (i_size_read(vi) + bh_size - 1) >> bh_size_bits;
957
958 rl = NULL;
959 err = err2 = nr_bhs = nr_recs = nr_locked_nis = 0;
960 page_is_dirty = rec_is_dirty = false;
961 rec_start_bh = NULL;
962 do {
963 bool is_retry = false;
964
965 if (likely(block < rec_block)) {
966 if (unlikely(block >= dblock)) {
967 clear_buffer_dirty(bh);
968 set_buffer_uptodate(bh);
969 continue;
970 }
971 /*
972 * This block is not the first one in the record. We
973 * ignore the buffer's dirty state because we could
974 * have raced with a parallel mark_ntfs_record_dirty().
975 */
976 if (!rec_is_dirty)
977 continue;
978 if (unlikely(err2)) {
979 if (err2 != -ENOMEM)
980 clear_buffer_dirty(bh);
981 continue;
982 }
983 } else /* if (block == rec_block) */ {
984 BUG_ON(block > rec_block);
985 /* This block is the first one in the record. */
986 rec_block += bhs_per_rec;
987 err2 = 0;
988 if (unlikely(block >= dblock)) {
989 clear_buffer_dirty(bh);
990 continue;
991 }
992 if (!buffer_dirty(bh)) {
993 /* Clean records are not written out. */
994 rec_is_dirty = false;
995 continue;
996 }
997 rec_is_dirty = true;
998 rec_start_bh = bh;
999 }
1000 /* Need to map the buffer if it is not mapped already. */
1001 if (unlikely(!buffer_mapped(bh))) {
1002 VCN vcn;
1003 LCN lcn;
1004 unsigned int vcn_ofs;
1005
1006 bh->b_bdev = vol->sb->s_bdev;
1007 /* Obtain the vcn and offset of the current block. */
1008 vcn = (VCN)block << bh_size_bits;
1009 vcn_ofs = vcn & vol->cluster_size_mask;
1010 vcn >>= vol->cluster_size_bits;
1011 if (!rl) {
1012lock_retry_remap:
1013 down_read(&ni->runlist.lock);
1014 rl = ni->runlist.rl;
1015 }
1016 if (likely(rl != NULL)) {
1017 /* Seek to element containing target vcn. */
1018 while (rl->length && rl[1].vcn <= vcn)
1019 rl++;
1020 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
1021 } else
1022 lcn = LCN_RL_NOT_MAPPED;
1023 /* Successful remap. */
1024 if (likely(lcn >= 0)) {
1025 /* Setup buffer head to correct block. */
1026 bh->b_blocknr = ((lcn <<
1027 vol->cluster_size_bits) +
1028 vcn_ofs) >> bh_size_bits;
1029 set_buffer_mapped(bh);
1030 } else {
1031 /*
1032 * Remap failed. Retry to map the runlist once
1033 * unless we are working on $MFT which always
1034 * has the whole of its runlist in memory.
1035 */
1036 if (!is_mft && !is_retry &&
1037 lcn == LCN_RL_NOT_MAPPED) {
1038 is_retry = true;
1039 /*
1040 * Attempt to map runlist, dropping
1041 * lock for the duration.
1042 */
1043 up_read(&ni->runlist.lock);
1044 err2 = ntfs_map_runlist(ni, vcn);
1045 if (likely(!err2))
1046 goto lock_retry_remap;
1047 if (err2 == -ENOMEM)
1048 page_is_dirty = true;
1049 lcn = err2;
1050 } else {
1051 err2 = -EIO;
1052 if (!rl)
1053 up_read(&ni->runlist.lock);
1054 }
1055 /* Hard error. Abort writing this record. */
1056 if (!err || err == -ENOMEM)
1057 err = err2;
1058 bh->b_blocknr = -1;
1059 ntfs_error(vol->sb, "Cannot write ntfs record "
1060 "0x%llx (inode 0x%lx, "
1061 "attribute type 0x%x) because "
1062 "its location on disk could "
1063 "not be determined (error "
1064 "code %lli).",
1065 (long long)block <<
1066 bh_size_bits >>
1067 vol->mft_record_size_bits,
1068 ni->mft_no, ni->type,
1069 (long long)lcn);
1070 /*
1071 * If this is not the first buffer, remove the
1072 * buffers in this record from the list of
1073 * buffers to write and clear their dirty bit
1074 * if not error -ENOMEM.
1075 */
1076 if (rec_start_bh != bh) {
1077 while (bhs[--nr_bhs] != rec_start_bh)
1078 ;
1079 if (err2 != -ENOMEM) {
1080 do {
1081 clear_buffer_dirty(
1082 rec_start_bh);
1083 } while ((rec_start_bh =
1084 rec_start_bh->
1085 b_this_page) !=
1086 bh);
1087 }
1088 }
1089 continue;
1090 }
1091 }
1092 BUG_ON(!buffer_uptodate(bh));
1093 BUG_ON(nr_bhs >= max_bhs);
1094 bhs[nr_bhs++] = bh;
1095 } while (block++, (bh = bh->b_this_page) != head);
1096 if (unlikely(rl))
1097 up_read(&ni->runlist.lock);
1098 /* If there were no dirty buffers, we are done. */
1099 if (!nr_bhs)
1100 goto done;
1101 /* Map the page so we can access its contents. */
1102 kaddr = kmap(page);
1103 /* Clear the page uptodate flag whilst the mst fixups are applied. */
1104 BUG_ON(!PageUptodate(page));
1105 ClearPageUptodate(page);
1106 for (i = 0; i < nr_bhs; i++) {
1107 unsigned int ofs;
1108
1109 /* Skip buffers which are not at the beginning of records. */
1110 if (i % bhs_per_rec)
1111 continue;
1112 tbh = bhs[i];
1113 ofs = bh_offset(tbh);
1114 if (is_mft) {
1115 ntfs_inode *tni;
1116 unsigned long mft_no;
1117
1118 /* Get the mft record number. */
1119 mft_no = (((s64)page->index << PAGE_SHIFT) + ofs)
1120 >> rec_size_bits;
1121 /* Check whether to write this mft record. */
1122 tni = NULL;
1123 if (!ntfs_may_write_mft_record(vol, mft_no,
1124 (MFT_RECORD*)(kaddr + ofs), &tni)) {
1125 /*
1126 * The record should not be written. This
1127 * means we need to redirty the page before
1128 * returning.
1129 */
1130 page_is_dirty = true;
1131 /*
1132 * Remove the buffers in this mft record from
1133 * the list of buffers to write.
1134 */
1135 do {
1136 bhs[i] = NULL;
1137 } while (++i % bhs_per_rec);
1138 continue;
1139 }
1140 /*
1141 * The record should be written. If a locked ntfs
1142 * inode was returned, add it to the array of locked
1143 * ntfs inodes.
1144 */
1145 if (tni)
1146 locked_nis[nr_locked_nis++] = tni;
1147 }
1148 /* Apply the mst protection fixups. */
1149 err2 = pre_write_mst_fixup((NTFS_RECORD*)(kaddr + ofs),
1150 rec_size);
1151 if (unlikely(err2)) {
1152 if (!err || err == -ENOMEM)
1153 err = -EIO;
1154 ntfs_error(vol->sb, "Failed to apply mst fixups "
1155 "(inode 0x%lx, attribute type 0x%x, "
1156 "page index 0x%lx, page offset 0x%x)!"
1157 " Unmount and run chkdsk.", vi->i_ino,
1158 ni->type, page->index, ofs);
1159 /*
1160 * Mark all the buffers in this record clean as we do
1161 * not want to write corrupt data to disk.
1162 */
1163 do {
1164 clear_buffer_dirty(bhs[i]);
1165 bhs[i] = NULL;
1166 } while (++i % bhs_per_rec);
1167 continue;
1168 }
1169 nr_recs++;
1170 }
1171 /* If no records are to be written out, we are done. */
1172 if (!nr_recs)
1173 goto unm_done;
1174 flush_dcache_page(page);
1175 /* Lock buffers and start synchronous write i/o on them. */
1176 for (i = 0; i < nr_bhs; i++) {
1177 tbh = bhs[i];
1178 if (!tbh)
1179 continue;
1180 if (!trylock_buffer(tbh))
1181 BUG();
1182 /* The buffer dirty state is now irrelevant, just clean it. */
1183 clear_buffer_dirty(tbh);
1184 BUG_ON(!buffer_uptodate(tbh));
1185 BUG_ON(!buffer_mapped(tbh));
1186 get_bh(tbh);
1187 tbh->b_end_io = end_buffer_write_sync;
1188 submit_bh(REQ_OP_WRITE, 0, tbh);
1189 }
1190 /* Synchronize the mft mirror now if not @sync. */
1191 if (is_mft && !sync)
1192 goto do_mirror;
1193do_wait:
1194 /* Wait on i/o completion of buffers. */
1195 for (i = 0; i < nr_bhs; i++) {
1196 tbh = bhs[i];
1197 if (!tbh)
1198 continue;
1199 wait_on_buffer(tbh);
1200 if (unlikely(!buffer_uptodate(tbh))) {
1201 ntfs_error(vol->sb, "I/O error while writing ntfs "
1202 "record buffer (inode 0x%lx, "
1203 "attribute type 0x%x, page index "
1204 "0x%lx, page offset 0x%lx)! Unmount "
1205 "and run chkdsk.", vi->i_ino, ni->type,
1206 page->index, bh_offset(tbh));
1207 if (!err || err == -ENOMEM)
1208 err = -EIO;
1209 /*
1210 * Set the buffer uptodate so the page and buffer
1211 * states do not become out of sync.
1212 */
1213 set_buffer_uptodate(tbh);
1214 }
1215 }
1216 /* If @sync, now synchronize the mft mirror. */
1217 if (is_mft && sync) {
1218do_mirror:
1219 for (i = 0; i < nr_bhs; i++) {
1220 unsigned long mft_no;
1221 unsigned int ofs;
1222
1223 /*
1224 * Skip buffers which are not at the beginning of
1225 * records.
1226 */
1227 if (i % bhs_per_rec)
1228 continue;
1229 tbh = bhs[i];
1230 /* Skip removed buffers (and hence records). */
1231 if (!tbh)
1232 continue;
1233 ofs = bh_offset(tbh);
1234 /* Get the mft record number. */
1235 mft_no = (((s64)page->index << PAGE_SHIFT) + ofs)
1236 >> rec_size_bits;
1237 if (mft_no < vol->mftmirr_size)
1238 ntfs_sync_mft_mirror(vol, mft_no,
1239 (MFT_RECORD*)(kaddr + ofs),
1240 sync);
1241 }
1242 if (!sync)
1243 goto do_wait;
1244 }
1245 /* Remove the mst protection fixups again. */
1246 for (i = 0; i < nr_bhs; i++) {
1247 if (!(i % bhs_per_rec)) {
1248 tbh = bhs[i];
1249 if (!tbh)
1250 continue;
1251 post_write_mst_fixup((NTFS_RECORD*)(kaddr +
1252 bh_offset(tbh)));
1253 }
1254 }
1255 flush_dcache_page(page);
1256unm_done:
1257 /* Unlock any locked inodes. */
1258 while (nr_locked_nis-- > 0) {
1259 ntfs_inode *tni, *base_tni;
1260
1261 tni = locked_nis[nr_locked_nis];
1262 /* Get the base inode. */
1263 mutex_lock(&tni->extent_lock);
1264 if (tni->nr_extents >= 0)
1265 base_tni = tni;
1266 else {
1267 base_tni = tni->ext.base_ntfs_ino;
1268 BUG_ON(!base_tni);
1269 }
1270 mutex_unlock(&tni->extent_lock);
1271 ntfs_debug("Unlocking %s inode 0x%lx.",
1272 tni == base_tni ? "base" : "extent",
1273 tni->mft_no);
1274 mutex_unlock(&tni->mrec_lock);
1275 atomic_dec(&tni->count);
1276 iput(VFS_I(base_tni));
1277 }
1278 SetPageUptodate(page);
1279 kunmap(page);
1280done:
1281 if (unlikely(err && err != -ENOMEM)) {
1282 /*
1283 * Set page error if there is only one ntfs record in the page.
1284 * Otherwise we would loose per-record granularity.
1285 */
1286 if (ni->itype.index.block_size == PAGE_SIZE)
1287 SetPageError(page);
1288 NVolSetErrors(vol);
1289 }
1290 if (page_is_dirty) {
1291 ntfs_debug("Page still contains one or more dirty ntfs "
1292 "records. Redirtying the page starting at "
1293 "record 0x%lx.", page->index <<
1294 (PAGE_SHIFT - rec_size_bits));
1295 redirty_page_for_writepage(wbc, page);
1296 unlock_page(page);
1297 } else {
1298 /*
1299 * Keep the VM happy. This must be done otherwise the
1300 * radix-tree tag PAGECACHE_TAG_DIRTY remains set even though
1301 * the page is clean.
1302 */
1303 BUG_ON(PageWriteback(page));
1304 set_page_writeback(page);
1305 unlock_page(page);
1306 end_page_writeback(page);
1307 }
1308 if (likely(!err))
1309 ntfs_debug("Done.");
1310 return err;
1311}
1312
1313/**
1314 * ntfs_writepage - write a @page to the backing store
1315 * @page: page cache page to write out
1316 * @wbc: writeback control structure
1317 *
1318 * This is called from the VM when it wants to have a dirty ntfs page cache
1319 * page cleaned. The VM has already locked the page and marked it clean.
1320 *
1321 * For non-resident attributes, ntfs_writepage() writes the @page by calling
1322 * the ntfs version of the generic block_write_full_page() function,
1323 * ntfs_write_block(), which in turn if necessary creates and writes the
1324 * buffers associated with the page asynchronously.
1325 *
1326 * For resident attributes, OTOH, ntfs_writepage() writes the @page by copying
1327 * the data to the mft record (which at this stage is most likely in memory).
1328 * The mft record is then marked dirty and written out asynchronously via the
1329 * vfs inode dirty code path for the inode the mft record belongs to or via the
1330 * vm page dirty code path for the page the mft record is in.
1331 *
1332 * Based on ntfs_readpage() and fs/buffer.c::block_write_full_page().
1333 *
1334 * Return 0 on success and -errno on error.
1335 */
1336static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
1337{
1338 loff_t i_size;
1339 struct inode *vi = page->mapping->host;
1340 ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);
1341 char *addr;
1342 ntfs_attr_search_ctx *ctx = NULL;
1343 MFT_RECORD *m = NULL;
1344 u32 attr_len;
1345 int err;
1346
1347retry_writepage:
1348 BUG_ON(!PageLocked(page));
1349 i_size = i_size_read(vi);
1350 /* Is the page fully outside i_size? (truncate in progress) */
1351 if (unlikely(page->index >= (i_size + PAGE_SIZE - 1) >>
1352 PAGE_SHIFT)) {
1353 /*
1354 * The page may have dirty, unmapped buffers. Make them
1355 * freeable here, so the page does not leak.
1356 */
1357 block_invalidatepage(page, 0, PAGE_SIZE);
1358 unlock_page(page);
1359 ntfs_debug("Write outside i_size - truncated?");
1360 return 0;
1361 }
1362 /*
1363 * Only $DATA attributes can be encrypted and only unnamed $DATA
1364 * attributes can be compressed. Index root can have the flags set but
1365 * this means to create compressed/encrypted files, not that the
1366 * attribute is compressed/encrypted. Note we need to check for
1367 * AT_INDEX_ALLOCATION since this is the type of both directory and
1368 * index inodes.
1369 */
1370 if (ni->type != AT_INDEX_ALLOCATION) {
1371 /* If file is encrypted, deny access, just like NT4. */
1372 if (NInoEncrypted(ni)) {
1373 unlock_page(page);
1374 BUG_ON(ni->type != AT_DATA);
1375 ntfs_debug("Denying write access to encrypted file.");
1376 return -EACCES;
1377 }
1378 /* Compressed data streams are handled in compress.c. */
1379 if (NInoNonResident(ni) && NInoCompressed(ni)) {
1380 BUG_ON(ni->type != AT_DATA);
1381 BUG_ON(ni->name_len);
1382 // TODO: Implement and replace this with
1383 // return ntfs_write_compressed_block(page);
1384 unlock_page(page);
1385 ntfs_error(vi->i_sb, "Writing to compressed files is "
1386 "not supported yet. Sorry.");
1387 return -EOPNOTSUPP;
1388 }
1389 // TODO: Implement and remove this check.
1390 if (NInoNonResident(ni) && NInoSparse(ni)) {
1391 unlock_page(page);
1392 ntfs_error(vi->i_sb, "Writing to sparse files is not "
1393 "supported yet. Sorry.");
1394 return -EOPNOTSUPP;
1395 }
1396 }
1397 /* NInoNonResident() == NInoIndexAllocPresent() */
1398 if (NInoNonResident(ni)) {
1399 /* We have to zero every time due to mmap-at-end-of-file. */
1400 if (page->index >= (i_size >> PAGE_SHIFT)) {
1401 /* The page straddles i_size. */
1402 unsigned int ofs = i_size & ~PAGE_MASK;
1403 zero_user_segment(page, ofs, PAGE_SIZE);
1404 }
1405 /* Handle mst protected attributes. */
1406 if (NInoMstProtected(ni))
1407 return ntfs_write_mst_block(page, wbc);
1408 /* Normal, non-resident data stream. */
1409 return ntfs_write_block(page, wbc);
1410 }
1411 /*
1412 * Attribute is resident, implying it is not compressed, encrypted, or
1413 * mst protected. This also means the attribute is smaller than an mft
1414 * record and hence smaller than a page, so can simply return error on
1415 * any pages with index above 0. Note the attribute can actually be
1416 * marked compressed but if it is resident the actual data is not
1417 * compressed so we are ok to ignore the compressed flag here.
1418 */
1419 BUG_ON(page_has_buffers(page));
1420 BUG_ON(!PageUptodate(page));
1421 if (unlikely(page->index > 0)) {
1422 ntfs_error(vi->i_sb, "BUG()! page->index (0x%lx) > 0. "
1423 "Aborting write.", page->index);
1424 BUG_ON(PageWriteback(page));
1425 set_page_writeback(page);
1426 unlock_page(page);
1427 end_page_writeback(page);
1428 return -EIO;
1429 }
1430 if (!NInoAttr(ni))
1431 base_ni = ni;
1432 else
1433 base_ni = ni->ext.base_ntfs_ino;
1434 /* Map, pin, and lock the mft record. */
1435 m = map_mft_record(base_ni);
1436 if (IS_ERR(m)) {
1437 err = PTR_ERR(m);
1438 m = NULL;
1439 ctx = NULL;
1440 goto err_out;
1441 }
1442 /*
1443 * If a parallel write made the attribute non-resident, drop the mft
1444 * record and retry the writepage.
1445 */
1446 if (unlikely(NInoNonResident(ni))) {
1447 unmap_mft_record(base_ni);
1448 goto retry_writepage;
1449 }
1450 ctx = ntfs_attr_get_search_ctx(base_ni, m);
1451 if (unlikely(!ctx)) {
1452 err = -ENOMEM;
1453 goto err_out;
1454 }
1455 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1456 CASE_SENSITIVE, 0, NULL, 0, ctx);
1457 if (unlikely(err))
1458 goto err_out;
1459 /*
1460 * Keep the VM happy. This must be done otherwise the radix-tree tag
1461 * PAGECACHE_TAG_DIRTY remains set even though the page is clean.
1462 */
1463 BUG_ON(PageWriteback(page));
1464 set_page_writeback(page);
1465 unlock_page(page);
1466 attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
1467 i_size = i_size_read(vi);
1468 if (unlikely(attr_len > i_size)) {
1469 /* Race with shrinking truncate or a failed truncate. */
1470 attr_len = i_size;
1471 /*
1472 * If the truncate failed, fix it up now. If a concurrent
1473 * truncate, we do its job, so it does not have to do anything.
1474 */
1475 err = ntfs_resident_attr_value_resize(ctx->mrec, ctx->attr,
1476 attr_len);
1477 /* Shrinking cannot fail. */
1478 BUG_ON(err);
1479 }
1480 addr = kmap_atomic(page);
1481 /* Copy the data from the page to the mft record. */
1482 memcpy((u8*)ctx->attr +
1483 le16_to_cpu(ctx->attr->data.resident.value_offset),
1484 addr, attr_len);
1485 /* Zero out of bounds area in the page cache page. */
1486 memset(addr + attr_len, 0, PAGE_SIZE - attr_len);
1487 kunmap_atomic(addr);
1488 flush_dcache_page(page);
1489 flush_dcache_mft_record_page(ctx->ntfs_ino);
1490 /* We are done with the page. */
1491 end_page_writeback(page);
1492 /* Finally, mark the mft record dirty, so it gets written back. */
1493 mark_mft_record_dirty(ctx->ntfs_ino);
1494 ntfs_attr_put_search_ctx(ctx);
1495 unmap_mft_record(base_ni);
1496 return 0;
1497err_out:
1498 if (err == -ENOMEM) {
1499 ntfs_warning(vi->i_sb, "Error allocating memory. Redirtying "
1500 "page so we try again later.");
1501 /*
1502 * Put the page back on mapping->dirty_pages, but leave its
1503 * buffers' dirty state as-is.
1504 */
1505 redirty_page_for_writepage(wbc, page);
1506 err = 0;
1507 } else {
1508 ntfs_error(vi->i_sb, "Resident attribute write failed with "
1509 "error %i.", err);
1510 SetPageError(page);
1511 NVolSetErrors(ni->vol);
1512 }
1513 unlock_page(page);
1514 if (ctx)
1515 ntfs_attr_put_search_ctx(ctx);
1516 if (m)
1517 unmap_mft_record(base_ni);
1518 return err;
1519}
1520
1521#endif /* NTFS_RW */
1522
1523/**
1524 * ntfs_bmap - map logical file block to physical device block
1525 * @mapping: address space mapping to which the block to be mapped belongs
1526 * @block: logical block to map to its physical device block
1527 *
1528 * For regular, non-resident files (i.e. not compressed and not encrypted), map
1529 * the logical @block belonging to the file described by the address space
1530 * mapping @mapping to its physical device block.
1531 *
1532 * The size of the block is equal to the @s_blocksize field of the super block
1533 * of the mounted file system which is guaranteed to be smaller than or equal
1534 * to the cluster size thus the block is guaranteed to fit entirely inside the
1535 * cluster which means we do not need to care how many contiguous bytes are
1536 * available after the beginning of the block.
1537 *
1538 * Return the physical device block if the mapping succeeded or 0 if the block
1539 * is sparse or there was an error.
1540 *
1541 * Note: This is a problem if someone tries to run bmap() on $Boot system file
1542 * as that really is in block zero but there is nothing we can do. bmap() is
1543 * just broken in that respect (just like it cannot distinguish sparse from
1544 * not available or error).
1545 */
1546static sector_t ntfs_bmap(struct address_space *mapping, sector_t block)
1547{
1548 s64 ofs, size;
1549 loff_t i_size;
1550 LCN lcn;
1551 unsigned long blocksize, flags;
1552 ntfs_inode *ni = NTFS_I(mapping->host);
1553 ntfs_volume *vol = ni->vol;
1554 unsigned delta;
1555 unsigned char blocksize_bits, cluster_size_shift;
1556
1557 ntfs_debug("Entering for mft_no 0x%lx, logical block 0x%llx.",
1558 ni->mft_no, (unsigned long long)block);
1559 if (ni->type != AT_DATA || !NInoNonResident(ni) || NInoEncrypted(ni)) {
1560 ntfs_error(vol->sb, "BMAP does not make sense for %s "
1561 "attributes, returning 0.",
1562 (ni->type != AT_DATA) ? "non-data" :
1563 (!NInoNonResident(ni) ? "resident" :
1564 "encrypted"));
1565 return 0;
1566 }
1567 /* None of these can happen. */
1568 BUG_ON(NInoCompressed(ni));
1569 BUG_ON(NInoMstProtected(ni));
1570 blocksize = vol->sb->s_blocksize;
1571 blocksize_bits = vol->sb->s_blocksize_bits;
1572 ofs = (s64)block << blocksize_bits;
1573 read_lock_irqsave(&ni->size_lock, flags);
1574 size = ni->initialized_size;
1575 i_size = i_size_read(VFS_I(ni));
1576 read_unlock_irqrestore(&ni->size_lock, flags);
1577 /*
1578 * If the offset is outside the initialized size or the block straddles
1579 * the initialized size then pretend it is a hole unless the
1580 * initialized size equals the file size.
1581 */
1582 if (unlikely(ofs >= size || (ofs + blocksize > size && size < i_size)))
1583 goto hole;
1584 cluster_size_shift = vol->cluster_size_bits;
1585 down_read(&ni->runlist.lock);
1586 lcn = ntfs_attr_vcn_to_lcn_nolock(ni, ofs >> cluster_size_shift, false);
1587 up_read(&ni->runlist.lock);
1588 if (unlikely(lcn < LCN_HOLE)) {
1589 /*
1590 * Step down to an integer to avoid gcc doing a long long
1591 * comparision in the switch when we know @lcn is between
1592 * LCN_HOLE and LCN_EIO (i.e. -1 to -5).
1593 *
1594 * Otherwise older gcc (at least on some architectures) will
1595 * try to use __cmpdi2() which is of course not available in
1596 * the kernel.
1597 */
1598 switch ((int)lcn) {
1599 case LCN_ENOENT:
1600 /*
1601 * If the offset is out of bounds then pretend it is a
1602 * hole.
1603 */
1604 goto hole;
1605 case LCN_ENOMEM:
1606 ntfs_error(vol->sb, "Not enough memory to complete "
1607 "mapping for inode 0x%lx. "
1608 "Returning 0.", ni->mft_no);
1609 break;
1610 default:
1611 ntfs_error(vol->sb, "Failed to complete mapping for "
1612 "inode 0x%lx. Run chkdsk. "
1613 "Returning 0.", ni->mft_no);
1614 break;
1615 }
1616 return 0;
1617 }
1618 if (lcn < 0) {
1619 /* It is a hole. */
1620hole:
1621 ntfs_debug("Done (returning hole).");
1622 return 0;
1623 }
1624 /*
1625 * The block is really allocated and fullfils all our criteria.
1626 * Convert the cluster to units of block size and return the result.
1627 */
1628 delta = ofs & vol->cluster_size_mask;
1629 if (unlikely(sizeof(block) < sizeof(lcn))) {
1630 block = lcn = ((lcn << cluster_size_shift) + delta) >>
1631 blocksize_bits;
1632 /* If the block number was truncated return 0. */
1633 if (unlikely(block != lcn)) {
1634 ntfs_error(vol->sb, "Physical block 0x%llx is too "
1635 "large to be returned, returning 0.",
1636 (long long)lcn);
1637 return 0;
1638 }
1639 } else
1640 block = ((lcn << cluster_size_shift) + delta) >>
1641 blocksize_bits;
1642 ntfs_debug("Done (returning block 0x%llx).", (unsigned long long)lcn);
1643 return block;
1644}
1645
1646/**
1647 * ntfs_normal_aops - address space operations for normal inodes and attributes
1648 *
1649 * Note these are not used for compressed or mst protected inodes and
1650 * attributes.
1651 */
1652const struct address_space_operations ntfs_normal_aops = {
1653 .readpage = ntfs_readpage,
1654#ifdef NTFS_RW
1655 .writepage = ntfs_writepage,
1656 .set_page_dirty = __set_page_dirty_buffers,
1657#endif /* NTFS_RW */
1658 .bmap = ntfs_bmap,
1659 .migratepage = buffer_migrate_page,
1660 .is_partially_uptodate = block_is_partially_uptodate,
1661 .error_remove_page = generic_error_remove_page,
1662};
1663
1664/**
1665 * ntfs_compressed_aops - address space operations for compressed inodes
1666 */
1667const struct address_space_operations ntfs_compressed_aops = {
1668 .readpage = ntfs_readpage,
1669#ifdef NTFS_RW
1670 .writepage = ntfs_writepage,
1671 .set_page_dirty = __set_page_dirty_buffers,
1672#endif /* NTFS_RW */
1673 .migratepage = buffer_migrate_page,
1674 .is_partially_uptodate = block_is_partially_uptodate,
1675 .error_remove_page = generic_error_remove_page,
1676};
1677
1678/**
1679 * ntfs_mst_aops - general address space operations for mst protecteed inodes
1680 * and attributes
1681 */
1682const struct address_space_operations ntfs_mst_aops = {
1683 .readpage = ntfs_readpage, /* Fill page with data. */
1684#ifdef NTFS_RW
1685 .writepage = ntfs_writepage, /* Write dirty page to disk. */
1686 .set_page_dirty = __set_page_dirty_nobuffers, /* Set the page dirty
1687 without touching the buffers
1688 belonging to the page. */
1689#endif /* NTFS_RW */
1690 .migratepage = buffer_migrate_page,
1691 .is_partially_uptodate = block_is_partially_uptodate,
1692 .error_remove_page = generic_error_remove_page,
1693};
1694
1695#ifdef NTFS_RW
1696
1697/**
1698 * mark_ntfs_record_dirty - mark an ntfs record dirty
1699 * @page: page containing the ntfs record to mark dirty
1700 * @ofs: byte offset within @page at which the ntfs record begins
1701 *
1702 * Set the buffers and the page in which the ntfs record is located dirty.
1703 *
1704 * The latter also marks the vfs inode the ntfs record belongs to dirty
1705 * (I_DIRTY_PAGES only).
1706 *
1707 * If the page does not have buffers, we create them and set them uptodate.
1708 * The page may not be locked which is why we need to handle the buffers under
1709 * the mapping->private_lock. Once the buffers are marked dirty we no longer
1710 * need the lock since try_to_free_buffers() does not free dirty buffers.
1711 */
1712void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) {
1713 struct address_space *mapping = page->mapping;
1714 ntfs_inode *ni = NTFS_I(mapping->host);
1715 struct buffer_head *bh, *head, *buffers_to_free = NULL;
1716 unsigned int end, bh_size, bh_ofs;
1717
1718 BUG_ON(!PageUptodate(page));
1719 end = ofs + ni->itype.index.block_size;
1720 bh_size = VFS_I(ni)->i_sb->s_blocksize;
1721 spin_lock(&mapping->private_lock);
1722 if (unlikely(!page_has_buffers(page))) {
1723 spin_unlock(&mapping->private_lock);
1724 bh = head = alloc_page_buffers(page, bh_size, true);
1725 spin_lock(&mapping->private_lock);
1726 if (likely(!page_has_buffers(page))) {
1727 struct buffer_head *tail;
1728
1729 do {
1730 set_buffer_uptodate(bh);
1731 tail = bh;
1732 bh = bh->b_this_page;
1733 } while (bh);
1734 tail->b_this_page = head;
1735 attach_page_private(page, head);
1736 } else
1737 buffers_to_free = bh;
1738 }
1739 bh = head = page_buffers(page);
1740 BUG_ON(!bh);
1741 do {
1742 bh_ofs = bh_offset(bh);
1743 if (bh_ofs + bh_size <= ofs)
1744 continue;
1745 if (unlikely(bh_ofs >= end))
1746 break;
1747 set_buffer_dirty(bh);
1748 } while ((bh = bh->b_this_page) != head);
1749 spin_unlock(&mapping->private_lock);
1750 __set_page_dirty_nobuffers(page);
1751 if (unlikely(buffers_to_free)) {
1752 do {
1753 bh = buffers_to_free->b_this_page;
1754 free_buffer_head(buffers_to_free);
1755 buffers_to_free = bh;
1756 } while (buffers_to_free);
1757 }
1758}
1759
1760#endif /* NTFS_RW */