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_folio().
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, 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_read_folio - fill a @folio of a @file with data from the device
362 * @file: open file to which the folio @folio belongs or NULL
363 * @folio: page cache folio to fill with data
364 *
365 * For non-resident attributes, ntfs_read_folio() fills the @folio of the open
366 * file @file by calling the ntfs version of the generic block_read_full_folio()
367 * function, ntfs_read_block(), which in turn creates and reads in the buffers
368 * associated with the folio asynchronously.
369 *
370 * For resident attributes, OTOH, ntfs_read_folio() fills @folio 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_read_folio(struct file *file, struct folio *folio)
379{
380 struct page *page = &folio->page;
381 loff_t i_size;
382 struct inode *vi;
383 ntfs_inode *ni, *base_ni;
384 u8 *addr;
385 ntfs_attr_search_ctx *ctx;
386 MFT_RECORD *mrec;
387 unsigned long flags;
388 u32 attr_len;
389 int err = 0;
390
391retry_readpage:
392 BUG_ON(!PageLocked(page));
393 vi = page->mapping->host;
394 i_size = i_size_read(vi);
395 /* Is the page fully outside i_size? (truncate in progress) */
396 if (unlikely(page->index >= (i_size + PAGE_SIZE - 1) >>
397 PAGE_SHIFT)) {
398 zero_user(page, 0, PAGE_SIZE);
399 ntfs_debug("Read outside i_size - truncated?");
400 goto done;
401 }
402 /*
403 * This can potentially happen because we clear PageUptodate() during
404 * ntfs_writepage() of MstProtected() attributes.
405 */
406 if (PageUptodate(page)) {
407 unlock_page(page);
408 return 0;
409 }
410 ni = NTFS_I(vi);
411 /*
412 * Only $DATA attributes can be encrypted and only unnamed $DATA
413 * attributes can be compressed. Index root can have the flags set but
414 * this means to create compressed/encrypted files, not that the
415 * attribute is compressed/encrypted. Note we need to check for
416 * AT_INDEX_ALLOCATION since this is the type of both directory and
417 * index inodes.
418 */
419 if (ni->type != AT_INDEX_ALLOCATION) {
420 /* If attribute is encrypted, deny access, just like NT4. */
421 if (NInoEncrypted(ni)) {
422 BUG_ON(ni->type != AT_DATA);
423 err = -EACCES;
424 goto err_out;
425 }
426 /* Compressed data streams are handled in compress.c. */
427 if (NInoNonResident(ni) && NInoCompressed(ni)) {
428 BUG_ON(ni->type != AT_DATA);
429 BUG_ON(ni->name_len);
430 return ntfs_read_compressed_block(page);
431 }
432 }
433 /* NInoNonResident() == NInoIndexAllocPresent() */
434 if (NInoNonResident(ni)) {
435 /* Normal, non-resident data stream. */
436 return ntfs_read_block(page);
437 }
438 /*
439 * Attribute is resident, implying it is not compressed or encrypted.
440 * This also means the attribute is smaller than an mft record and
441 * hence smaller than a page, so can simply zero out any pages with
442 * index above 0. Note the attribute can actually be marked compressed
443 * but if it is resident the actual data is not compressed so we are
444 * ok to ignore the compressed flag here.
445 */
446 if (unlikely(page->index > 0)) {
447 zero_user(page, 0, PAGE_SIZE);
448 goto done;
449 }
450 if (!NInoAttr(ni))
451 base_ni = ni;
452 else
453 base_ni = ni->ext.base_ntfs_ino;
454 /* Map, pin, and lock the mft record. */
455 mrec = map_mft_record(base_ni);
456 if (IS_ERR(mrec)) {
457 err = PTR_ERR(mrec);
458 goto err_out;
459 }
460 /*
461 * If a parallel write made the attribute non-resident, drop the mft
462 * record and retry the read_folio.
463 */
464 if (unlikely(NInoNonResident(ni))) {
465 unmap_mft_record(base_ni);
466 goto retry_readpage;
467 }
468 ctx = ntfs_attr_get_search_ctx(base_ni, mrec);
469 if (unlikely(!ctx)) {
470 err = -ENOMEM;
471 goto unm_err_out;
472 }
473 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
474 CASE_SENSITIVE, 0, NULL, 0, ctx);
475 if (unlikely(err))
476 goto put_unm_err_out;
477 attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
478 read_lock_irqsave(&ni->size_lock, flags);
479 if (unlikely(attr_len > ni->initialized_size))
480 attr_len = ni->initialized_size;
481 i_size = i_size_read(vi);
482 read_unlock_irqrestore(&ni->size_lock, flags);
483 if (unlikely(attr_len > i_size)) {
484 /* Race with shrinking truncate. */
485 attr_len = i_size;
486 }
487 addr = kmap_atomic(page);
488 /* Copy the data to the page. */
489 memcpy(addr, (u8*)ctx->attr +
490 le16_to_cpu(ctx->attr->data.resident.value_offset),
491 attr_len);
492 /* Zero the remainder of the page. */
493 memset(addr + attr_len, 0, PAGE_SIZE - attr_len);
494 flush_dcache_page(page);
495 kunmap_atomic(addr);
496put_unm_err_out:
497 ntfs_attr_put_search_ctx(ctx);
498unm_err_out:
499 unmap_mft_record(base_ni);
500done:
501 SetPageUptodate(page);
502err_out:
503 unlock_page(page);
504 return err;
505}
506
507#ifdef NTFS_RW
508
509/**
510 * ntfs_write_block - write a @page to the backing store
511 * @page: page cache page to write out
512 * @wbc: writeback control structure
513 *
514 * This function is for writing pages belonging to non-resident, non-mst
515 * protected attributes to their backing store.
516 *
517 * For a page with buffers, map and write the dirty buffers asynchronously
518 * under page writeback. For a page without buffers, create buffers for the
519 * page, then proceed as above.
520 *
521 * If a page doesn't have buffers the page dirty state is definitive. If a page
522 * does have buffers, the page dirty state is just a hint, and the buffer dirty
523 * state is definitive. (A hint which has rules: dirty buffers against a clean
524 * page is illegal. Other combinations are legal and need to be handled. In
525 * particular a dirty page containing clean buffers for example.)
526 *
527 * Return 0 on success and -errno on error.
528 *
529 * Based on ntfs_read_block() and __block_write_full_page().
530 */
531static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
532{
533 VCN vcn;
534 LCN lcn;
535 s64 initialized_size;
536 loff_t i_size;
537 sector_t block, dblock, iblock;
538 struct inode *vi;
539 ntfs_inode *ni;
540 ntfs_volume *vol;
541 runlist_element *rl;
542 struct buffer_head *bh, *head;
543 unsigned long flags;
544 unsigned int blocksize, vcn_ofs;
545 int err;
546 bool need_end_writeback;
547 unsigned char blocksize_bits;
548
549 vi = page->mapping->host;
550 ni = NTFS_I(vi);
551 vol = ni->vol;
552
553 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
554 "0x%lx.", ni->mft_no, ni->type, page->index);
555
556 BUG_ON(!NInoNonResident(ni));
557 BUG_ON(NInoMstProtected(ni));
558 blocksize = vol->sb->s_blocksize;
559 blocksize_bits = vol->sb->s_blocksize_bits;
560 if (!page_has_buffers(page)) {
561 BUG_ON(!PageUptodate(page));
562 create_empty_buffers(page, blocksize,
563 (1 << BH_Uptodate) | (1 << BH_Dirty));
564 if (unlikely(!page_has_buffers(page))) {
565 ntfs_warning(vol->sb, "Error allocating page "
566 "buffers. Redirtying page so we try "
567 "again later.");
568 /*
569 * Put the page back on mapping->dirty_pages, but leave
570 * its buffers' dirty state as-is.
571 */
572 redirty_page_for_writepage(wbc, page);
573 unlock_page(page);
574 return 0;
575 }
576 }
577 bh = head = page_buffers(page);
578 BUG_ON(!bh);
579
580 /* NOTE: Different naming scheme to ntfs_read_block()! */
581
582 /* The first block in the page. */
583 block = (s64)page->index << (PAGE_SHIFT - blocksize_bits);
584
585 read_lock_irqsave(&ni->size_lock, flags);
586 i_size = i_size_read(vi);
587 initialized_size = ni->initialized_size;
588 read_unlock_irqrestore(&ni->size_lock, flags);
589
590 /* The first out of bounds block for the data size. */
591 dblock = (i_size + blocksize - 1) >> blocksize_bits;
592
593 /* The last (fully or partially) initialized block. */
594 iblock = initialized_size >> blocksize_bits;
595
596 /*
597 * Be very careful. We have no exclusion from block_dirty_folio
598 * here, and the (potentially unmapped) buffers may become dirty at
599 * any time. If a buffer becomes dirty here after we've inspected it
600 * then we just miss that fact, and the page stays dirty.
601 *
602 * Buffers outside i_size may be dirtied by block_dirty_folio;
603 * handle that here by just cleaning them.
604 */
605
606 /*
607 * Loop through all the buffers in the page, mapping all the dirty
608 * buffers to disk addresses and handling any aliases from the
609 * underlying block device's mapping.
610 */
611 rl = NULL;
612 err = 0;
613 do {
614 bool is_retry = false;
615
616 if (unlikely(block >= dblock)) {
617 /*
618 * Mapped buffers outside i_size will occur, because
619 * this page can be outside i_size when there is a
620 * truncate in progress. The contents of such buffers
621 * were zeroed by ntfs_writepage().
622 *
623 * FIXME: What about the small race window where
624 * ntfs_writepage() has not done any clearing because
625 * the page was within i_size but before we get here,
626 * vmtruncate() modifies i_size?
627 */
628 clear_buffer_dirty(bh);
629 set_buffer_uptodate(bh);
630 continue;
631 }
632
633 /* Clean buffers are not written out, so no need to map them. */
634 if (!buffer_dirty(bh))
635 continue;
636
637 /* Make sure we have enough initialized size. */
638 if (unlikely((block >= iblock) &&
639 (initialized_size < i_size))) {
640 /*
641 * If this page is fully outside initialized
642 * size, zero out all pages between the current
643 * initialized size and the current page. Just
644 * use ntfs_read_folio() to do the zeroing
645 * transparently.
646 */
647 if (block > iblock) {
648 // TODO:
649 // For each page do:
650 // - read_cache_page()
651 // Again for each page do:
652 // - wait_on_page_locked()
653 // - Check (PageUptodate(page) &&
654 // !PageError(page))
655 // Update initialized size in the attribute and
656 // in the inode.
657 // Again, for each page do:
658 // block_dirty_folio();
659 // put_page()
660 // We don't need to wait on the writes.
661 // Update iblock.
662 }
663 /*
664 * The current page straddles initialized size. Zero
665 * all non-uptodate buffers and set them uptodate (and
666 * dirty?). Note, there aren't any non-uptodate buffers
667 * if the page is uptodate.
668 * FIXME: For an uptodate page, the buffers may need to
669 * be written out because they were not initialized on
670 * disk before.
671 */
672 if (!PageUptodate(page)) {
673 // TODO:
674 // Zero any non-uptodate buffers up to i_size.
675 // Set them uptodate and dirty.
676 }
677 // TODO:
678 // Update initialized size in the attribute and in the
679 // inode (up to i_size).
680 // Update iblock.
681 // FIXME: This is inefficient. Try to batch the two
682 // size changes to happen in one go.
683 ntfs_error(vol->sb, "Writing beyond initialized size "
684 "is not supported yet. Sorry.");
685 err = -EOPNOTSUPP;
686 break;
687 // Do NOT set_buffer_new() BUT DO clear buffer range
688 // outside write request range.
689 // set_buffer_uptodate() on complete buffers as well as
690 // set_buffer_dirty().
691 }
692
693 /* No need to map buffers that are already mapped. */
694 if (buffer_mapped(bh))
695 continue;
696
697 /* Unmapped, dirty buffer. Need to map it. */
698 bh->b_bdev = vol->sb->s_bdev;
699
700 /* Convert block into corresponding vcn and offset. */
701 vcn = (VCN)block << blocksize_bits;
702 vcn_ofs = vcn & vol->cluster_size_mask;
703 vcn >>= vol->cluster_size_bits;
704 if (!rl) {
705lock_retry_remap:
706 down_read(&ni->runlist.lock);
707 rl = ni->runlist.rl;
708 }
709 if (likely(rl != NULL)) {
710 /* Seek to element containing target vcn. */
711 while (rl->length && rl[1].vcn <= vcn)
712 rl++;
713 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
714 } else
715 lcn = LCN_RL_NOT_MAPPED;
716 /* Successful remap. */
717 if (lcn >= 0) {
718 /* Setup buffer head to point to correct block. */
719 bh->b_blocknr = ((lcn << vol->cluster_size_bits) +
720 vcn_ofs) >> blocksize_bits;
721 set_buffer_mapped(bh);
722 continue;
723 }
724 /* It is a hole, need to instantiate it. */
725 if (lcn == LCN_HOLE) {
726 u8 *kaddr;
727 unsigned long *bpos, *bend;
728
729 /* Check if the buffer is zero. */
730 kaddr = kmap_atomic(page);
731 bpos = (unsigned long *)(kaddr + bh_offset(bh));
732 bend = (unsigned long *)((u8*)bpos + blocksize);
733 do {
734 if (unlikely(*bpos))
735 break;
736 } while (likely(++bpos < bend));
737 kunmap_atomic(kaddr);
738 if (bpos == bend) {
739 /*
740 * Buffer is zero and sparse, no need to write
741 * it.
742 */
743 bh->b_blocknr = -1;
744 clear_buffer_dirty(bh);
745 continue;
746 }
747 // TODO: Instantiate the hole.
748 // clear_buffer_new(bh);
749 // clean_bdev_bh_alias(bh);
750 ntfs_error(vol->sb, "Writing into sparse regions is "
751 "not supported yet. Sorry.");
752 err = -EOPNOTSUPP;
753 break;
754 }
755 /* If first try and runlist unmapped, map and retry. */
756 if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
757 is_retry = true;
758 /*
759 * Attempt to map runlist, dropping lock for
760 * the duration.
761 */
762 up_read(&ni->runlist.lock);
763 err = ntfs_map_runlist(ni, vcn);
764 if (likely(!err))
765 goto lock_retry_remap;
766 rl = NULL;
767 } else if (!rl)
768 up_read(&ni->runlist.lock);
769 /*
770 * If buffer is outside the runlist, truncate has cut it out
771 * of the runlist. Just clean and clear the buffer and set it
772 * uptodate so it can get discarded by the VM.
773 */
774 if (err == -ENOENT || lcn == LCN_ENOENT) {
775 bh->b_blocknr = -1;
776 clear_buffer_dirty(bh);
777 zero_user(page, bh_offset(bh), blocksize);
778 set_buffer_uptodate(bh);
779 err = 0;
780 continue;
781 }
782 /* Failed to map the buffer, even after retrying. */
783 if (!err)
784 err = -EIO;
785 bh->b_blocknr = -1;
786 ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
787 "attribute type 0x%x, vcn 0x%llx, offset 0x%x "
788 "because its location on disk could not be "
789 "determined%s (error code %i).", ni->mft_no,
790 ni->type, (unsigned long long)vcn,
791 vcn_ofs, is_retry ? " even after "
792 "retrying" : "", err);
793 break;
794 } while (block++, (bh = bh->b_this_page) != head);
795
796 /* Release the lock if we took it. */
797 if (rl)
798 up_read(&ni->runlist.lock);
799
800 /* For the error case, need to reset bh to the beginning. */
801 bh = head;
802
803 /* Just an optimization, so ->read_folio() is not called later. */
804 if (unlikely(!PageUptodate(page))) {
805 int uptodate = 1;
806 do {
807 if (!buffer_uptodate(bh)) {
808 uptodate = 0;
809 bh = head;
810 break;
811 }
812 } while ((bh = bh->b_this_page) != head);
813 if (uptodate)
814 SetPageUptodate(page);
815 }
816
817 /* Setup all mapped, dirty buffers for async write i/o. */
818 do {
819 if (buffer_mapped(bh) && buffer_dirty(bh)) {
820 lock_buffer(bh);
821 if (test_clear_buffer_dirty(bh)) {
822 BUG_ON(!buffer_uptodate(bh));
823 mark_buffer_async_write(bh);
824 } else
825 unlock_buffer(bh);
826 } else if (unlikely(err)) {
827 /*
828 * For the error case. The buffer may have been set
829 * dirty during attachment to a dirty page.
830 */
831 if (err != -ENOMEM)
832 clear_buffer_dirty(bh);
833 }
834 } while ((bh = bh->b_this_page) != head);
835
836 if (unlikely(err)) {
837 // TODO: Remove the -EOPNOTSUPP check later on...
838 if (unlikely(err == -EOPNOTSUPP))
839 err = 0;
840 else if (err == -ENOMEM) {
841 ntfs_warning(vol->sb, "Error allocating memory. "
842 "Redirtying page so we try again "
843 "later.");
844 /*
845 * Put the page back on mapping->dirty_pages, but
846 * leave its buffer's dirty state as-is.
847 */
848 redirty_page_for_writepage(wbc, page);
849 err = 0;
850 } else
851 SetPageError(page);
852 }
853
854 BUG_ON(PageWriteback(page));
855 set_page_writeback(page); /* Keeps try_to_free_buffers() away. */
856
857 /* Submit the prepared buffers for i/o. */
858 need_end_writeback = true;
859 do {
860 struct buffer_head *next = bh->b_this_page;
861 if (buffer_async_write(bh)) {
862 submit_bh(REQ_OP_WRITE, bh);
863 need_end_writeback = false;
864 }
865 bh = next;
866 } while (bh != head);
867 unlock_page(page);
868
869 /* If no i/o was started, need to end_page_writeback(). */
870 if (unlikely(need_end_writeback))
871 end_page_writeback(page);
872
873 ntfs_debug("Done.");
874 return err;
875}
876
877/**
878 * ntfs_write_mst_block - write a @page to the backing store
879 * @page: page cache page to write out
880 * @wbc: writeback control structure
881 *
882 * This function is for writing pages belonging to non-resident, mst protected
883 * attributes to their backing store. The only supported attributes are index
884 * allocation and $MFT/$DATA. Both directory inodes and index inodes are
885 * supported for the index allocation case.
886 *
887 * The page must remain locked for the duration of the write because we apply
888 * the mst fixups, write, and then undo the fixups, so if we were to unlock the
889 * page before undoing the fixups, any other user of the page will see the
890 * page contents as corrupt.
891 *
892 * We clear the page uptodate flag for the duration of the function to ensure
893 * exclusion for the $MFT/$DATA case against someone mapping an mft record we
894 * are about to apply the mst fixups to.
895 *
896 * Return 0 on success and -errno on error.
897 *
898 * Based on ntfs_write_block(), ntfs_mft_writepage(), and
899 * write_mft_record_nolock().
900 */
901static int ntfs_write_mst_block(struct page *page,
902 struct writeback_control *wbc)
903{
904 sector_t block, dblock, rec_block;
905 struct inode *vi = page->mapping->host;
906 ntfs_inode *ni = NTFS_I(vi);
907 ntfs_volume *vol = ni->vol;
908 u8 *kaddr;
909 unsigned int rec_size = ni->itype.index.block_size;
910 ntfs_inode *locked_nis[PAGE_SIZE / NTFS_BLOCK_SIZE];
911 struct buffer_head *bh, *head, *tbh, *rec_start_bh;
912 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
913 runlist_element *rl;
914 int i, nr_locked_nis, nr_recs, nr_bhs, max_bhs, bhs_per_rec, err, err2;
915 unsigned bh_size, rec_size_bits;
916 bool sync, is_mft, page_is_dirty, rec_is_dirty;
917 unsigned char bh_size_bits;
918
919 if (WARN_ON(rec_size < NTFS_BLOCK_SIZE))
920 return -EINVAL;
921
922 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
923 "0x%lx.", vi->i_ino, ni->type, page->index);
924 BUG_ON(!NInoNonResident(ni));
925 BUG_ON(!NInoMstProtected(ni));
926 is_mft = (S_ISREG(vi->i_mode) && !vi->i_ino);
927 /*
928 * NOTE: ntfs_write_mst_block() would be called for $MFTMirr if a page
929 * in its page cache were to be marked dirty. However this should
930 * never happen with the current driver and considering we do not
931 * handle this case here we do want to BUG(), at least for now.
932 */
933 BUG_ON(!(is_mft || S_ISDIR(vi->i_mode) ||
934 (NInoAttr(ni) && ni->type == AT_INDEX_ALLOCATION)));
935 bh_size = vol->sb->s_blocksize;
936 bh_size_bits = vol->sb->s_blocksize_bits;
937 max_bhs = PAGE_SIZE / bh_size;
938 BUG_ON(!max_bhs);
939 BUG_ON(max_bhs > MAX_BUF_PER_PAGE);
940
941 /* Were we called for sync purposes? */
942 sync = (wbc->sync_mode == WB_SYNC_ALL);
943
944 /* Make sure we have mapped buffers. */
945 bh = head = page_buffers(page);
946 BUG_ON(!bh);
947
948 rec_size_bits = ni->itype.index.block_size_bits;
949 BUG_ON(!(PAGE_SIZE >> rec_size_bits));
950 bhs_per_rec = rec_size >> bh_size_bits;
951 BUG_ON(!bhs_per_rec);
952
953 /* The first block in the page. */
954 rec_block = block = (sector_t)page->index <<
955 (PAGE_SHIFT - bh_size_bits);
956
957 /* The first out of bounds block for the data size. */
958 dblock = (i_size_read(vi) + bh_size - 1) >> bh_size_bits;
959
960 rl = NULL;
961 err = err2 = nr_bhs = nr_recs = nr_locked_nis = 0;
962 page_is_dirty = rec_is_dirty = false;
963 rec_start_bh = NULL;
964 do {
965 bool is_retry = false;
966
967 if (likely(block < rec_block)) {
968 if (unlikely(block >= dblock)) {
969 clear_buffer_dirty(bh);
970 set_buffer_uptodate(bh);
971 continue;
972 }
973 /*
974 * This block is not the first one in the record. We
975 * ignore the buffer's dirty state because we could
976 * have raced with a parallel mark_ntfs_record_dirty().
977 */
978 if (!rec_is_dirty)
979 continue;
980 if (unlikely(err2)) {
981 if (err2 != -ENOMEM)
982 clear_buffer_dirty(bh);
983 continue;
984 }
985 } else /* if (block == rec_block) */ {
986 BUG_ON(block > rec_block);
987 /* This block is the first one in the record. */
988 rec_block += bhs_per_rec;
989 err2 = 0;
990 if (unlikely(block >= dblock)) {
991 clear_buffer_dirty(bh);
992 continue;
993 }
994 if (!buffer_dirty(bh)) {
995 /* Clean records are not written out. */
996 rec_is_dirty = false;
997 continue;
998 }
999 rec_is_dirty = true;
1000 rec_start_bh = bh;
1001 }
1002 /* Need to map the buffer if it is not mapped already. */
1003 if (unlikely(!buffer_mapped(bh))) {
1004 VCN vcn;
1005 LCN lcn;
1006 unsigned int vcn_ofs;
1007
1008 bh->b_bdev = vol->sb->s_bdev;
1009 /* Obtain the vcn and offset of the current block. */
1010 vcn = (VCN)block << bh_size_bits;
1011 vcn_ofs = vcn & vol->cluster_size_mask;
1012 vcn >>= vol->cluster_size_bits;
1013 if (!rl) {
1014lock_retry_remap:
1015 down_read(&ni->runlist.lock);
1016 rl = ni->runlist.rl;
1017 }
1018 if (likely(rl != NULL)) {
1019 /* Seek to element containing target vcn. */
1020 while (rl->length && rl[1].vcn <= vcn)
1021 rl++;
1022 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
1023 } else
1024 lcn = LCN_RL_NOT_MAPPED;
1025 /* Successful remap. */
1026 if (likely(lcn >= 0)) {
1027 /* Setup buffer head to correct block. */
1028 bh->b_blocknr = ((lcn <<
1029 vol->cluster_size_bits) +
1030 vcn_ofs) >> bh_size_bits;
1031 set_buffer_mapped(bh);
1032 } else {
1033 /*
1034 * Remap failed. Retry to map the runlist once
1035 * unless we are working on $MFT which always
1036 * has the whole of its runlist in memory.
1037 */
1038 if (!is_mft && !is_retry &&
1039 lcn == LCN_RL_NOT_MAPPED) {
1040 is_retry = true;
1041 /*
1042 * Attempt to map runlist, dropping
1043 * lock for the duration.
1044 */
1045 up_read(&ni->runlist.lock);
1046 err2 = ntfs_map_runlist(ni, vcn);
1047 if (likely(!err2))
1048 goto lock_retry_remap;
1049 if (err2 == -ENOMEM)
1050 page_is_dirty = true;
1051 lcn = err2;
1052 } else {
1053 err2 = -EIO;
1054 if (!rl)
1055 up_read(&ni->runlist.lock);
1056 }
1057 /* Hard error. Abort writing this record. */
1058 if (!err || err == -ENOMEM)
1059 err = err2;
1060 bh->b_blocknr = -1;
1061 ntfs_error(vol->sb, "Cannot write ntfs record "
1062 "0x%llx (inode 0x%lx, "
1063 "attribute type 0x%x) because "
1064 "its location on disk could "
1065 "not be determined (error "
1066 "code %lli).",
1067 (long long)block <<
1068 bh_size_bits >>
1069 vol->mft_record_size_bits,
1070 ni->mft_no, ni->type,
1071 (long long)lcn);
1072 /*
1073 * If this is not the first buffer, remove the
1074 * buffers in this record from the list of
1075 * buffers to write and clear their dirty bit
1076 * if not error -ENOMEM.
1077 */
1078 if (rec_start_bh != bh) {
1079 while (bhs[--nr_bhs] != rec_start_bh)
1080 ;
1081 if (err2 != -ENOMEM) {
1082 do {
1083 clear_buffer_dirty(
1084 rec_start_bh);
1085 } while ((rec_start_bh =
1086 rec_start_bh->
1087 b_this_page) !=
1088 bh);
1089 }
1090 }
1091 continue;
1092 }
1093 }
1094 BUG_ON(!buffer_uptodate(bh));
1095 BUG_ON(nr_bhs >= max_bhs);
1096 bhs[nr_bhs++] = bh;
1097 } while (block++, (bh = bh->b_this_page) != head);
1098 if (unlikely(rl))
1099 up_read(&ni->runlist.lock);
1100 /* If there were no dirty buffers, we are done. */
1101 if (!nr_bhs)
1102 goto done;
1103 /* Map the page so we can access its contents. */
1104 kaddr = kmap(page);
1105 /* Clear the page uptodate flag whilst the mst fixups are applied. */
1106 BUG_ON(!PageUptodate(page));
1107 ClearPageUptodate(page);
1108 for (i = 0; i < nr_bhs; i++) {
1109 unsigned int ofs;
1110
1111 /* Skip buffers which are not at the beginning of records. */
1112 if (i % bhs_per_rec)
1113 continue;
1114 tbh = bhs[i];
1115 ofs = bh_offset(tbh);
1116 if (is_mft) {
1117 ntfs_inode *tni;
1118 unsigned long mft_no;
1119
1120 /* Get the mft record number. */
1121 mft_no = (((s64)page->index << PAGE_SHIFT) + ofs)
1122 >> rec_size_bits;
1123 /* Check whether to write this mft record. */
1124 tni = NULL;
1125 if (!ntfs_may_write_mft_record(vol, mft_no,
1126 (MFT_RECORD*)(kaddr + ofs), &tni)) {
1127 /*
1128 * The record should not be written. This
1129 * means we need to redirty the page before
1130 * returning.
1131 */
1132 page_is_dirty = true;
1133 /*
1134 * Remove the buffers in this mft record from
1135 * the list of buffers to write.
1136 */
1137 do {
1138 bhs[i] = NULL;
1139 } while (++i % bhs_per_rec);
1140 continue;
1141 }
1142 /*
1143 * The record should be written. If a locked ntfs
1144 * inode was returned, add it to the array of locked
1145 * ntfs inodes.
1146 */
1147 if (tni)
1148 locked_nis[nr_locked_nis++] = tni;
1149 }
1150 /* Apply the mst protection fixups. */
1151 err2 = pre_write_mst_fixup((NTFS_RECORD*)(kaddr + ofs),
1152 rec_size);
1153 if (unlikely(err2)) {
1154 if (!err || err == -ENOMEM)
1155 err = -EIO;
1156 ntfs_error(vol->sb, "Failed to apply mst fixups "
1157 "(inode 0x%lx, attribute type 0x%x, "
1158 "page index 0x%lx, page offset 0x%x)!"
1159 " Unmount and run chkdsk.", vi->i_ino,
1160 ni->type, page->index, ofs);
1161 /*
1162 * Mark all the buffers in this record clean as we do
1163 * not want to write corrupt data to disk.
1164 */
1165 do {
1166 clear_buffer_dirty(bhs[i]);
1167 bhs[i] = NULL;
1168 } while (++i % bhs_per_rec);
1169 continue;
1170 }
1171 nr_recs++;
1172 }
1173 /* If no records are to be written out, we are done. */
1174 if (!nr_recs)
1175 goto unm_done;
1176 flush_dcache_page(page);
1177 /* Lock buffers and start synchronous write i/o on them. */
1178 for (i = 0; i < nr_bhs; i++) {
1179 tbh = bhs[i];
1180 if (!tbh)
1181 continue;
1182 if (!trylock_buffer(tbh))
1183 BUG();
1184 /* The buffer dirty state is now irrelevant, just clean it. */
1185 clear_buffer_dirty(tbh);
1186 BUG_ON(!buffer_uptodate(tbh));
1187 BUG_ON(!buffer_mapped(tbh));
1188 get_bh(tbh);
1189 tbh->b_end_io = end_buffer_write_sync;
1190 submit_bh(REQ_OP_WRITE, tbh);
1191 }
1192 /* Synchronize the mft mirror now if not @sync. */
1193 if (is_mft && !sync)
1194 goto do_mirror;
1195do_wait:
1196 /* Wait on i/o completion of buffers. */
1197 for (i = 0; i < nr_bhs; i++) {
1198 tbh = bhs[i];
1199 if (!tbh)
1200 continue;
1201 wait_on_buffer(tbh);
1202 if (unlikely(!buffer_uptodate(tbh))) {
1203 ntfs_error(vol->sb, "I/O error while writing ntfs "
1204 "record buffer (inode 0x%lx, "
1205 "attribute type 0x%x, page index "
1206 "0x%lx, page offset 0x%lx)! Unmount "
1207 "and run chkdsk.", vi->i_ino, ni->type,
1208 page->index, bh_offset(tbh));
1209 if (!err || err == -ENOMEM)
1210 err = -EIO;
1211 /*
1212 * Set the buffer uptodate so the page and buffer
1213 * states do not become out of sync.
1214 */
1215 set_buffer_uptodate(tbh);
1216 }
1217 }
1218 /* If @sync, now synchronize the mft mirror. */
1219 if (is_mft && sync) {
1220do_mirror:
1221 for (i = 0; i < nr_bhs; i++) {
1222 unsigned long mft_no;
1223 unsigned int ofs;
1224
1225 /*
1226 * Skip buffers which are not at the beginning of
1227 * records.
1228 */
1229 if (i % bhs_per_rec)
1230 continue;
1231 tbh = bhs[i];
1232 /* Skip removed buffers (and hence records). */
1233 if (!tbh)
1234 continue;
1235 ofs = bh_offset(tbh);
1236 /* Get the mft record number. */
1237 mft_no = (((s64)page->index << PAGE_SHIFT) + ofs)
1238 >> rec_size_bits;
1239 if (mft_no < vol->mftmirr_size)
1240 ntfs_sync_mft_mirror(vol, mft_no,
1241 (MFT_RECORD*)(kaddr + ofs),
1242 sync);
1243 }
1244 if (!sync)
1245 goto do_wait;
1246 }
1247 /* Remove the mst protection fixups again. */
1248 for (i = 0; i < nr_bhs; i++) {
1249 if (!(i % bhs_per_rec)) {
1250 tbh = bhs[i];
1251 if (!tbh)
1252 continue;
1253 post_write_mst_fixup((NTFS_RECORD*)(kaddr +
1254 bh_offset(tbh)));
1255 }
1256 }
1257 flush_dcache_page(page);
1258unm_done:
1259 /* Unlock any locked inodes. */
1260 while (nr_locked_nis-- > 0) {
1261 ntfs_inode *tni, *base_tni;
1262
1263 tni = locked_nis[nr_locked_nis];
1264 /* Get the base inode. */
1265 mutex_lock(&tni->extent_lock);
1266 if (tni->nr_extents >= 0)
1267 base_tni = tni;
1268 else {
1269 base_tni = tni->ext.base_ntfs_ino;
1270 BUG_ON(!base_tni);
1271 }
1272 mutex_unlock(&tni->extent_lock);
1273 ntfs_debug("Unlocking %s inode 0x%lx.",
1274 tni == base_tni ? "base" : "extent",
1275 tni->mft_no);
1276 mutex_unlock(&tni->mrec_lock);
1277 atomic_dec(&tni->count);
1278 iput(VFS_I(base_tni));
1279 }
1280 SetPageUptodate(page);
1281 kunmap(page);
1282done:
1283 if (unlikely(err && err != -ENOMEM)) {
1284 /*
1285 * Set page error if there is only one ntfs record in the page.
1286 * Otherwise we would loose per-record granularity.
1287 */
1288 if (ni->itype.index.block_size == PAGE_SIZE)
1289 SetPageError(page);
1290 NVolSetErrors(vol);
1291 }
1292 if (page_is_dirty) {
1293 ntfs_debug("Page still contains one or more dirty ntfs "
1294 "records. Redirtying the page starting at "
1295 "record 0x%lx.", page->index <<
1296 (PAGE_SHIFT - rec_size_bits));
1297 redirty_page_for_writepage(wbc, page);
1298 unlock_page(page);
1299 } else {
1300 /*
1301 * Keep the VM happy. This must be done otherwise the
1302 * radix-tree tag PAGECACHE_TAG_DIRTY remains set even though
1303 * the page is clean.
1304 */
1305 BUG_ON(PageWriteback(page));
1306 set_page_writeback(page);
1307 unlock_page(page);
1308 end_page_writeback(page);
1309 }
1310 if (likely(!err))
1311 ntfs_debug("Done.");
1312 return err;
1313}
1314
1315/**
1316 * ntfs_writepage - write a @page to the backing store
1317 * @page: page cache page to write out
1318 * @wbc: writeback control structure
1319 *
1320 * This is called from the VM when it wants to have a dirty ntfs page cache
1321 * page cleaned. The VM has already locked the page and marked it clean.
1322 *
1323 * For non-resident attributes, ntfs_writepage() writes the @page by calling
1324 * the ntfs version of the generic block_write_full_page() function,
1325 * ntfs_write_block(), which in turn if necessary creates and writes the
1326 * buffers associated with the page asynchronously.
1327 *
1328 * For resident attributes, OTOH, ntfs_writepage() writes the @page by copying
1329 * the data to the mft record (which at this stage is most likely in memory).
1330 * The mft record is then marked dirty and written out asynchronously via the
1331 * vfs inode dirty code path for the inode the mft record belongs to or via the
1332 * vm page dirty code path for the page the mft record is in.
1333 *
1334 * Based on ntfs_read_folio() and fs/buffer.c::block_write_full_page().
1335 *
1336 * Return 0 on success and -errno on error.
1337 */
1338static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
1339{
1340 loff_t i_size;
1341 struct inode *vi = page->mapping->host;
1342 ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);
1343 char *addr;
1344 ntfs_attr_search_ctx *ctx = NULL;
1345 MFT_RECORD *m = NULL;
1346 u32 attr_len;
1347 int err;
1348
1349retry_writepage:
1350 BUG_ON(!PageLocked(page));
1351 i_size = i_size_read(vi);
1352 /* Is the page fully outside i_size? (truncate in progress) */
1353 if (unlikely(page->index >= (i_size + PAGE_SIZE - 1) >>
1354 PAGE_SHIFT)) {
1355 struct folio *folio = page_folio(page);
1356 /*
1357 * The page may have dirty, unmapped buffers. Make them
1358 * freeable here, so the page does not leak.
1359 */
1360 block_invalidate_folio(folio, 0, folio_size(folio));
1361 folio_unlock(folio);
1362 ntfs_debug("Write outside i_size - truncated?");
1363 return 0;
1364 }
1365 /*
1366 * Only $DATA attributes can be encrypted and only unnamed $DATA
1367 * attributes can be compressed. Index root can have the flags set but
1368 * this means to create compressed/encrypted files, not that the
1369 * attribute is compressed/encrypted. Note we need to check for
1370 * AT_INDEX_ALLOCATION since this is the type of both directory and
1371 * index inodes.
1372 */
1373 if (ni->type != AT_INDEX_ALLOCATION) {
1374 /* If file is encrypted, deny access, just like NT4. */
1375 if (NInoEncrypted(ni)) {
1376 unlock_page(page);
1377 BUG_ON(ni->type != AT_DATA);
1378 ntfs_debug("Denying write access to encrypted file.");
1379 return -EACCES;
1380 }
1381 /* Compressed data streams are handled in compress.c. */
1382 if (NInoNonResident(ni) && NInoCompressed(ni)) {
1383 BUG_ON(ni->type != AT_DATA);
1384 BUG_ON(ni->name_len);
1385 // TODO: Implement and replace this with
1386 // return ntfs_write_compressed_block(page);
1387 unlock_page(page);
1388 ntfs_error(vi->i_sb, "Writing to compressed files is "
1389 "not supported yet. Sorry.");
1390 return -EOPNOTSUPP;
1391 }
1392 // TODO: Implement and remove this check.
1393 if (NInoNonResident(ni) && NInoSparse(ni)) {
1394 unlock_page(page);
1395 ntfs_error(vi->i_sb, "Writing to sparse files is not "
1396 "supported yet. Sorry.");
1397 return -EOPNOTSUPP;
1398 }
1399 }
1400 /* NInoNonResident() == NInoIndexAllocPresent() */
1401 if (NInoNonResident(ni)) {
1402 /* We have to zero every time due to mmap-at-end-of-file. */
1403 if (page->index >= (i_size >> PAGE_SHIFT)) {
1404 /* The page straddles i_size. */
1405 unsigned int ofs = i_size & ~PAGE_MASK;
1406 zero_user_segment(page, ofs, PAGE_SIZE);
1407 }
1408 /* Handle mst protected attributes. */
1409 if (NInoMstProtected(ni))
1410 return ntfs_write_mst_block(page, wbc);
1411 /* Normal, non-resident data stream. */
1412 return ntfs_write_block(page, wbc);
1413 }
1414 /*
1415 * Attribute is resident, implying it is not compressed, encrypted, or
1416 * mst protected. This also means the attribute is smaller than an mft
1417 * record and hence smaller than a page, so can simply return error on
1418 * any pages with index above 0. Note the attribute can actually be
1419 * marked compressed but if it is resident the actual data is not
1420 * compressed so we are ok to ignore the compressed flag here.
1421 */
1422 BUG_ON(page_has_buffers(page));
1423 BUG_ON(!PageUptodate(page));
1424 if (unlikely(page->index > 0)) {
1425 ntfs_error(vi->i_sb, "BUG()! page->index (0x%lx) > 0. "
1426 "Aborting write.", page->index);
1427 BUG_ON(PageWriteback(page));
1428 set_page_writeback(page);
1429 unlock_page(page);
1430 end_page_writeback(page);
1431 return -EIO;
1432 }
1433 if (!NInoAttr(ni))
1434 base_ni = ni;
1435 else
1436 base_ni = ni->ext.base_ntfs_ino;
1437 /* Map, pin, and lock the mft record. */
1438 m = map_mft_record(base_ni);
1439 if (IS_ERR(m)) {
1440 err = PTR_ERR(m);
1441 m = NULL;
1442 ctx = NULL;
1443 goto err_out;
1444 }
1445 /*
1446 * If a parallel write made the attribute non-resident, drop the mft
1447 * record and retry the writepage.
1448 */
1449 if (unlikely(NInoNonResident(ni))) {
1450 unmap_mft_record(base_ni);
1451 goto retry_writepage;
1452 }
1453 ctx = ntfs_attr_get_search_ctx(base_ni, m);
1454 if (unlikely(!ctx)) {
1455 err = -ENOMEM;
1456 goto err_out;
1457 }
1458 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1459 CASE_SENSITIVE, 0, NULL, 0, ctx);
1460 if (unlikely(err))
1461 goto err_out;
1462 /*
1463 * Keep the VM happy. This must be done otherwise the radix-tree tag
1464 * PAGECACHE_TAG_DIRTY remains set even though the page is clean.
1465 */
1466 BUG_ON(PageWriteback(page));
1467 set_page_writeback(page);
1468 unlock_page(page);
1469 attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
1470 i_size = i_size_read(vi);
1471 if (unlikely(attr_len > i_size)) {
1472 /* Race with shrinking truncate or a failed truncate. */
1473 attr_len = i_size;
1474 /*
1475 * If the truncate failed, fix it up now. If a concurrent
1476 * truncate, we do its job, so it does not have to do anything.
1477 */
1478 err = ntfs_resident_attr_value_resize(ctx->mrec, ctx->attr,
1479 attr_len);
1480 /* Shrinking cannot fail. */
1481 BUG_ON(err);
1482 }
1483 addr = kmap_atomic(page);
1484 /* Copy the data from the page to the mft record. */
1485 memcpy((u8*)ctx->attr +
1486 le16_to_cpu(ctx->attr->data.resident.value_offset),
1487 addr, attr_len);
1488 /* Zero out of bounds area in the page cache page. */
1489 memset(addr + attr_len, 0, PAGE_SIZE - attr_len);
1490 kunmap_atomic(addr);
1491 flush_dcache_page(page);
1492 flush_dcache_mft_record_page(ctx->ntfs_ino);
1493 /* We are done with the page. */
1494 end_page_writeback(page);
1495 /* Finally, mark the mft record dirty, so it gets written back. */
1496 mark_mft_record_dirty(ctx->ntfs_ino);
1497 ntfs_attr_put_search_ctx(ctx);
1498 unmap_mft_record(base_ni);
1499 return 0;
1500err_out:
1501 if (err == -ENOMEM) {
1502 ntfs_warning(vi->i_sb, "Error allocating memory. Redirtying "
1503 "page so we try again later.");
1504 /*
1505 * Put the page back on mapping->dirty_pages, but leave its
1506 * buffers' dirty state as-is.
1507 */
1508 redirty_page_for_writepage(wbc, page);
1509 err = 0;
1510 } else {
1511 ntfs_error(vi->i_sb, "Resident attribute write failed with "
1512 "error %i.", err);
1513 SetPageError(page);
1514 NVolSetErrors(ni->vol);
1515 }
1516 unlock_page(page);
1517 if (ctx)
1518 ntfs_attr_put_search_ctx(ctx);
1519 if (m)
1520 unmap_mft_record(base_ni);
1521 return err;
1522}
1523
1524#endif /* NTFS_RW */
1525
1526/**
1527 * ntfs_bmap - map logical file block to physical device block
1528 * @mapping: address space mapping to which the block to be mapped belongs
1529 * @block: logical block to map to its physical device block
1530 *
1531 * For regular, non-resident files (i.e. not compressed and not encrypted), map
1532 * the logical @block belonging to the file described by the address space
1533 * mapping @mapping to its physical device block.
1534 *
1535 * The size of the block is equal to the @s_blocksize field of the super block
1536 * of the mounted file system which is guaranteed to be smaller than or equal
1537 * to the cluster size thus the block is guaranteed to fit entirely inside the
1538 * cluster which means we do not need to care how many contiguous bytes are
1539 * available after the beginning of the block.
1540 *
1541 * Return the physical device block if the mapping succeeded or 0 if the block
1542 * is sparse or there was an error.
1543 *
1544 * Note: This is a problem if someone tries to run bmap() on $Boot system file
1545 * as that really is in block zero but there is nothing we can do. bmap() is
1546 * just broken in that respect (just like it cannot distinguish sparse from
1547 * not available or error).
1548 */
1549static sector_t ntfs_bmap(struct address_space *mapping, sector_t block)
1550{
1551 s64 ofs, size;
1552 loff_t i_size;
1553 LCN lcn;
1554 unsigned long blocksize, flags;
1555 ntfs_inode *ni = NTFS_I(mapping->host);
1556 ntfs_volume *vol = ni->vol;
1557 unsigned delta;
1558 unsigned char blocksize_bits, cluster_size_shift;
1559
1560 ntfs_debug("Entering for mft_no 0x%lx, logical block 0x%llx.",
1561 ni->mft_no, (unsigned long long)block);
1562 if (ni->type != AT_DATA || !NInoNonResident(ni) || NInoEncrypted(ni)) {
1563 ntfs_error(vol->sb, "BMAP does not make sense for %s "
1564 "attributes, returning 0.",
1565 (ni->type != AT_DATA) ? "non-data" :
1566 (!NInoNonResident(ni) ? "resident" :
1567 "encrypted"));
1568 return 0;
1569 }
1570 /* None of these can happen. */
1571 BUG_ON(NInoCompressed(ni));
1572 BUG_ON(NInoMstProtected(ni));
1573 blocksize = vol->sb->s_blocksize;
1574 blocksize_bits = vol->sb->s_blocksize_bits;
1575 ofs = (s64)block << blocksize_bits;
1576 read_lock_irqsave(&ni->size_lock, flags);
1577 size = ni->initialized_size;
1578 i_size = i_size_read(VFS_I(ni));
1579 read_unlock_irqrestore(&ni->size_lock, flags);
1580 /*
1581 * If the offset is outside the initialized size or the block straddles
1582 * the initialized size then pretend it is a hole unless the
1583 * initialized size equals the file size.
1584 */
1585 if (unlikely(ofs >= size || (ofs + blocksize > size && size < i_size)))
1586 goto hole;
1587 cluster_size_shift = vol->cluster_size_bits;
1588 down_read(&ni->runlist.lock);
1589 lcn = ntfs_attr_vcn_to_lcn_nolock(ni, ofs >> cluster_size_shift, false);
1590 up_read(&ni->runlist.lock);
1591 if (unlikely(lcn < LCN_HOLE)) {
1592 /*
1593 * Step down to an integer to avoid gcc doing a long long
1594 * comparision in the switch when we know @lcn is between
1595 * LCN_HOLE and LCN_EIO (i.e. -1 to -5).
1596 *
1597 * Otherwise older gcc (at least on some architectures) will
1598 * try to use __cmpdi2() which is of course not available in
1599 * the kernel.
1600 */
1601 switch ((int)lcn) {
1602 case LCN_ENOENT:
1603 /*
1604 * If the offset is out of bounds then pretend it is a
1605 * hole.
1606 */
1607 goto hole;
1608 case LCN_ENOMEM:
1609 ntfs_error(vol->sb, "Not enough memory to complete "
1610 "mapping for inode 0x%lx. "
1611 "Returning 0.", ni->mft_no);
1612 break;
1613 default:
1614 ntfs_error(vol->sb, "Failed to complete mapping for "
1615 "inode 0x%lx. Run chkdsk. "
1616 "Returning 0.", ni->mft_no);
1617 break;
1618 }
1619 return 0;
1620 }
1621 if (lcn < 0) {
1622 /* It is a hole. */
1623hole:
1624 ntfs_debug("Done (returning hole).");
1625 return 0;
1626 }
1627 /*
1628 * The block is really allocated and fullfils all our criteria.
1629 * Convert the cluster to units of block size and return the result.
1630 */
1631 delta = ofs & vol->cluster_size_mask;
1632 if (unlikely(sizeof(block) < sizeof(lcn))) {
1633 block = lcn = ((lcn << cluster_size_shift) + delta) >>
1634 blocksize_bits;
1635 /* If the block number was truncated return 0. */
1636 if (unlikely(block != lcn)) {
1637 ntfs_error(vol->sb, "Physical block 0x%llx is too "
1638 "large to be returned, returning 0.",
1639 (long long)lcn);
1640 return 0;
1641 }
1642 } else
1643 block = ((lcn << cluster_size_shift) + delta) >>
1644 blocksize_bits;
1645 ntfs_debug("Done (returning block 0x%llx).", (unsigned long long)lcn);
1646 return block;
1647}
1648
1649/**
1650 * ntfs_normal_aops - address space operations for normal inodes and attributes
1651 *
1652 * Note these are not used for compressed or mst protected inodes and
1653 * attributes.
1654 */
1655const struct address_space_operations ntfs_normal_aops = {
1656 .read_folio = ntfs_read_folio,
1657#ifdef NTFS_RW
1658 .writepage = ntfs_writepage,
1659 .dirty_folio = block_dirty_folio,
1660#endif /* NTFS_RW */
1661 .bmap = ntfs_bmap,
1662 .migrate_folio = buffer_migrate_folio,
1663 .is_partially_uptodate = block_is_partially_uptodate,
1664 .error_remove_page = generic_error_remove_page,
1665};
1666
1667/**
1668 * ntfs_compressed_aops - address space operations for compressed inodes
1669 */
1670const struct address_space_operations ntfs_compressed_aops = {
1671 .read_folio = ntfs_read_folio,
1672#ifdef NTFS_RW
1673 .writepage = ntfs_writepage,
1674 .dirty_folio = block_dirty_folio,
1675#endif /* NTFS_RW */
1676 .migrate_folio = buffer_migrate_folio,
1677 .is_partially_uptodate = block_is_partially_uptodate,
1678 .error_remove_page = generic_error_remove_page,
1679};
1680
1681/**
1682 * ntfs_mst_aops - general address space operations for mst protecteed inodes
1683 * and attributes
1684 */
1685const struct address_space_operations ntfs_mst_aops = {
1686 .read_folio = ntfs_read_folio, /* Fill page with data. */
1687#ifdef NTFS_RW
1688 .writepage = ntfs_writepage, /* Write dirty page to disk. */
1689 .dirty_folio = filemap_dirty_folio,
1690#endif /* NTFS_RW */
1691 .migrate_folio = buffer_migrate_folio,
1692 .is_partially_uptodate = block_is_partially_uptodate,
1693 .error_remove_page = generic_error_remove_page,
1694};
1695
1696#ifdef NTFS_RW
1697
1698/**
1699 * mark_ntfs_record_dirty - mark an ntfs record dirty
1700 * @page: page containing the ntfs record to mark dirty
1701 * @ofs: byte offset within @page at which the ntfs record begins
1702 *
1703 * Set the buffers and the page in which the ntfs record is located dirty.
1704 *
1705 * The latter also marks the vfs inode the ntfs record belongs to dirty
1706 * (I_DIRTY_PAGES only).
1707 *
1708 * If the page does not have buffers, we create them and set them uptodate.
1709 * The page may not be locked which is why we need to handle the buffers under
1710 * the mapping->private_lock. Once the buffers are marked dirty we no longer
1711 * need the lock since try_to_free_buffers() does not free dirty buffers.
1712 */
1713void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) {
1714 struct address_space *mapping = page->mapping;
1715 ntfs_inode *ni = NTFS_I(mapping->host);
1716 struct buffer_head *bh, *head, *buffers_to_free = NULL;
1717 unsigned int end, bh_size, bh_ofs;
1718
1719 BUG_ON(!PageUptodate(page));
1720 end = ofs + ni->itype.index.block_size;
1721 bh_size = VFS_I(ni)->i_sb->s_blocksize;
1722 spin_lock(&mapping->private_lock);
1723 if (unlikely(!page_has_buffers(page))) {
1724 spin_unlock(&mapping->private_lock);
1725 bh = head = alloc_page_buffers(page, bh_size, true);
1726 spin_lock(&mapping->private_lock);
1727 if (likely(!page_has_buffers(page))) {
1728 struct buffer_head *tail;
1729
1730 do {
1731 set_buffer_uptodate(bh);
1732 tail = bh;
1733 bh = bh->b_this_page;
1734 } while (bh);
1735 tail->b_this_page = head;
1736 attach_page_private(page, head);
1737 } else
1738 buffers_to_free = bh;
1739 }
1740 bh = head = page_buffers(page);
1741 BUG_ON(!bh);
1742 do {
1743 bh_ofs = bh_offset(bh);
1744 if (bh_ofs + bh_size <= ofs)
1745 continue;
1746 if (unlikely(bh_ofs >= end))
1747 break;
1748 set_buffer_dirty(bh);
1749 } while ((bh = bh->b_this_page) != head);
1750 spin_unlock(&mapping->private_lock);
1751 filemap_dirty_folio(mapping, page_folio(page));
1752 if (unlikely(buffers_to_free)) {
1753 do {
1754 bh = buffers_to_free->b_this_page;
1755 free_buffer_head(buffers_to_free);
1756 buffers_to_free = bh;
1757 } while (buffers_to_free);
1758 }
1759}
1760
1761#endif /* NTFS_RW */
1762

source code of linux/fs/ntfs/aops.c