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