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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * mm/truncate.c - code for taking down pages from address_spaces
4 *
5 * Copyright (C) 2002, Linus Torvalds
6 *
7 * 10Sep2002 Andrew Morton
8 * Initial version.
9 */
10
11#include <linux/kernel.h>
12#include <linux/backing-dev.h>
13#include <linux/dax.h>
14#include <linux/gfp.h>
15#include <linux/mm.h>
16#include <linux/swap.h>
17#include <linux/export.h>
18#include <linux/pagemap.h>
19#include <linux/highmem.h>
20#include <linux/pagevec.h>
21#include <linux/task_io_accounting_ops.h>
22#include <linux/shmem_fs.h>
23#include <linux/rmap.h>
24#include "internal.h"
25
26/*
27 * Regular page slots are stabilized by the page lock even without the tree
28 * itself locked. These unlocked entries need verification under the tree
29 * lock.
30 */
31static inline void __clear_shadow_entry(struct address_space *mapping,
32 pgoff_t index, void *entry)
33{
34 XA_STATE(xas, &mapping->i_pages, index);
35
36 xas_set_update(&xas, workingset_update_node);
37 if (xas_load(&xas) != entry)
38 return;
39 xas_store(&xas, NULL);
40}
41
42static void clear_shadow_entry(struct address_space *mapping, pgoff_t index,
43 void *entry)
44{
45 spin_lock(&mapping->host->i_lock);
46 xa_lock_irq(&mapping->i_pages);
47 __clear_shadow_entry(mapping, index, entry);
48 xa_unlock_irq(&mapping->i_pages);
49 if (mapping_shrinkable(mapping))
50 inode_add_lru(mapping->host);
51 spin_unlock(&mapping->host->i_lock);
52}
53
54/*
55 * Unconditionally remove exceptional entries. Usually called from truncate
56 * path. Note that the folio_batch may be altered by this function by removing
57 * exceptional entries similar to what folio_batch_remove_exceptionals() does.
58 */
59static void truncate_folio_batch_exceptionals(struct address_space *mapping,
60 struct folio_batch *fbatch, pgoff_t *indices)
61{
62 int i, j;
63 bool dax;
64
65 /* Handled by shmem itself */
66 if (shmem_mapping(mapping))
67 return;
68
69 for (j = 0; j < folio_batch_count(fbatch); j++)
70 if (xa_is_value(fbatch->folios[j]))
71 break;
72
73 if (j == folio_batch_count(fbatch))
74 return;
75
76 dax = dax_mapping(mapping);
77 if (!dax) {
78 spin_lock(&mapping->host->i_lock);
79 xa_lock_irq(&mapping->i_pages);
80 }
81
82 for (i = j; i < folio_batch_count(fbatch); i++) {
83 struct folio *folio = fbatch->folios[i];
84 pgoff_t index = indices[i];
85
86 if (!xa_is_value(folio)) {
87 fbatch->folios[j++] = folio;
88 continue;
89 }
90
91 if (unlikely(dax)) {
92 dax_delete_mapping_entry(mapping, index);
93 continue;
94 }
95
96 __clear_shadow_entry(mapping, index, folio);
97 }
98
99 if (!dax) {
100 xa_unlock_irq(&mapping->i_pages);
101 if (mapping_shrinkable(mapping))
102 inode_add_lru(mapping->host);
103 spin_unlock(&mapping->host->i_lock);
104 }
105 fbatch->nr = j;
106}
107
108/*
109 * Invalidate exceptional entry if easily possible. This handles exceptional
110 * entries for invalidate_inode_pages().
111 */
112static int invalidate_exceptional_entry(struct address_space *mapping,
113 pgoff_t index, void *entry)
114{
115 /* Handled by shmem itself, or for DAX we do nothing. */
116 if (shmem_mapping(mapping) || dax_mapping(mapping))
117 return 1;
118 clear_shadow_entry(mapping, index, entry);
119 return 1;
120}
121
122/*
123 * Invalidate exceptional entry if clean. This handles exceptional entries for
124 * invalidate_inode_pages2() so for DAX it evicts only clean entries.
125 */
126static int invalidate_exceptional_entry2(struct address_space *mapping,
127 pgoff_t index, void *entry)
128{
129 /* Handled by shmem itself */
130 if (shmem_mapping(mapping))
131 return 1;
132 if (dax_mapping(mapping))
133 return dax_invalidate_mapping_entry_sync(mapping, index);
134 clear_shadow_entry(mapping, index, entry);
135 return 1;
136}
137
138/**
139 * folio_invalidate - Invalidate part or all of a folio.
140 * @folio: The folio which is affected.
141 * @offset: start of the range to invalidate
142 * @length: length of the range to invalidate
143 *
144 * folio_invalidate() is called when all or part of the folio has become
145 * invalidated by a truncate operation.
146 *
147 * folio_invalidate() does not have to release all buffers, but it must
148 * ensure that no dirty buffer is left outside @offset and that no I/O
149 * is underway against any of the blocks which are outside the truncation
150 * point. Because the caller is about to free (and possibly reuse) those
151 * blocks on-disk.
152 */
153void folio_invalidate(struct folio *folio, size_t offset, size_t length)
154{
155 const struct address_space_operations *aops = folio->mapping->a_ops;
156
157 if (aops->invalidate_folio)
158 aops->invalidate_folio(folio, offset, length);
159}
160EXPORT_SYMBOL_GPL(folio_invalidate);
161
162/*
163 * If truncate cannot remove the fs-private metadata from the page, the page
164 * becomes orphaned. It will be left on the LRU and may even be mapped into
165 * user pagetables if we're racing with filemap_fault().
166 *
167 * We need to bail out if page->mapping is no longer equal to the original
168 * mapping. This happens a) when the VM reclaimed the page while we waited on
169 * its lock, b) when a concurrent invalidate_mapping_pages got there first and
170 * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
171 */
172static void truncate_cleanup_folio(struct folio *folio)
173{
174 if (folio_mapped(folio))
175 unmap_mapping_folio(folio);
176
177 if (folio_has_private(folio))
178 folio_invalidate(folio, 0, folio_size(folio));
179
180 /*
181 * Some filesystems seem to re-dirty the page even after
182 * the VM has canceled the dirty bit (eg ext3 journaling).
183 * Hence dirty accounting check is placed after invalidation.
184 */
185 folio_cancel_dirty(folio);
186 folio_clear_mappedtodisk(folio);
187}
188
189int truncate_inode_folio(struct address_space *mapping, struct folio *folio)
190{
191 if (folio->mapping != mapping)
192 return -EIO;
193
194 truncate_cleanup_folio(folio);
195 filemap_remove_folio(folio);
196 return 0;
197}
198
199/*
200 * Handle partial folios. The folio may be entirely within the
201 * range if a split has raced with us. If not, we zero the part of the
202 * folio that's within the [start, end] range, and then split the folio if
203 * it's large. split_page_range() will discard pages which now lie beyond
204 * i_size, and we rely on the caller to discard pages which lie within a
205 * newly created hole.
206 *
207 * Returns false if splitting failed so the caller can avoid
208 * discarding the entire folio which is stubbornly unsplit.
209 */
210bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end)
211{
212 loff_t pos = folio_pos(folio);
213 unsigned int offset, length;
214
215 if (pos < start)
216 offset = start - pos;
217 else
218 offset = 0;
219 length = folio_size(folio);
220 if (pos + length <= (u64)end)
221 length = length - offset;
222 else
223 length = end + 1 - pos - offset;
224
225 folio_wait_writeback(folio);
226 if (length == folio_size(folio)) {
227 truncate_inode_folio(folio->mapping, folio);
228 return true;
229 }
230
231 /*
232 * We may be zeroing pages we're about to discard, but it avoids
233 * doing a complex calculation here, and then doing the zeroing
234 * anyway if the page split fails.
235 */
236 folio_zero_range(folio, offset, length);
237
238 if (folio_has_private(folio))
239 folio_invalidate(folio, offset, length);
240 if (!folio_test_large(folio))
241 return true;
242 if (split_folio(folio) == 0)
243 return true;
244 if (folio_test_dirty(folio))
245 return false;
246 truncate_inode_folio(folio->mapping, folio);
247 return true;
248}
249
250/*
251 * Used to get rid of pages on hardware memory corruption.
252 */
253int generic_error_remove_folio(struct address_space *mapping,
254 struct folio *folio)
255{
256 if (!mapping)
257 return -EINVAL;
258 /*
259 * Only punch for normal data pages for now.
260 * Handling other types like directories would need more auditing.
261 */
262 if (!S_ISREG(mapping->host->i_mode))
263 return -EIO;
264 return truncate_inode_folio(mapping, folio);
265}
266EXPORT_SYMBOL(generic_error_remove_folio);
267
268/**
269 * mapping_evict_folio() - Remove an unused folio from the page-cache.
270 * @mapping: The mapping this folio belongs to.
271 * @folio: The folio to remove.
272 *
273 * Safely remove one folio from the page cache.
274 * It only drops clean, unused folios.
275 *
276 * Context: Folio must be locked.
277 * Return: The number of pages successfully removed.
278 */
279long mapping_evict_folio(struct address_space *mapping, struct folio *folio)
280{
281 /* The page may have been truncated before it was locked */
282 if (!mapping)
283 return 0;
284 if (folio_test_dirty(folio) || folio_test_writeback(folio))
285 return 0;
286 /* The refcount will be elevated if any page in the folio is mapped */
287 if (folio_ref_count(folio) >
288 folio_nr_pages(folio) + folio_has_private(folio) + 1)
289 return 0;
290 if (!filemap_release_folio(folio, 0))
291 return 0;
292
293 return remove_mapping(mapping, folio);
294}
295
296/**
297 * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets
298 * @mapping: mapping to truncate
299 * @lstart: offset from which to truncate
300 * @lend: offset to which to truncate (inclusive)
301 *
302 * Truncate the page cache, removing the pages that are between
303 * specified offsets (and zeroing out partial pages
304 * if lstart or lend + 1 is not page aligned).
305 *
306 * Truncate takes two passes - the first pass is nonblocking. It will not
307 * block on page locks and it will not block on writeback. The second pass
308 * will wait. This is to prevent as much IO as possible in the affected region.
309 * The first pass will remove most pages, so the search cost of the second pass
310 * is low.
311 *
312 * We pass down the cache-hot hint to the page freeing code. Even if the
313 * mapping is large, it is probably the case that the final pages are the most
314 * recently touched, and freeing happens in ascending file offset order.
315 *
316 * Note that since ->invalidate_folio() accepts range to invalidate
317 * truncate_inode_pages_range is able to handle cases where lend + 1 is not
318 * page aligned properly.
319 */
320void truncate_inode_pages_range(struct address_space *mapping,
321 loff_t lstart, loff_t lend)
322{
323 pgoff_t start; /* inclusive */
324 pgoff_t end; /* exclusive */
325 struct folio_batch fbatch;
326 pgoff_t indices[PAGEVEC_SIZE];
327 pgoff_t index;
328 int i;
329 struct folio *folio;
330 bool same_folio;
331
332 if (mapping_empty(mapping))
333 return;
334
335 /*
336 * 'start' and 'end' always covers the range of pages to be fully
337 * truncated. Partial pages are covered with 'partial_start' at the
338 * start of the range and 'partial_end' at the end of the range.
339 * Note that 'end' is exclusive while 'lend' is inclusive.
340 */
341 start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
342 if (lend == -1)
343 /*
344 * lend == -1 indicates end-of-file so we have to set 'end'
345 * to the highest possible pgoff_t and since the type is
346 * unsigned we're using -1.
347 */
348 end = -1;
349 else
350 end = (lend + 1) >> PAGE_SHIFT;
351
352 folio_batch_init(&fbatch);
353 index = start;
354 while (index < end && find_lock_entries(mapping, &index, end - 1,
355 &fbatch, indices)) {
356 truncate_folio_batch_exceptionals(mapping, &fbatch, indices);
357 for (i = 0; i < folio_batch_count(&fbatch); i++)
358 truncate_cleanup_folio(fbatch.folios[i]);
359 delete_from_page_cache_batch(mapping, &fbatch);
360 for (i = 0; i < folio_batch_count(&fbatch); i++)
361 folio_unlock(fbatch.folios[i]);
362 folio_batch_release(&fbatch);
363 cond_resched();
364 }
365
366 same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT);
367 folio = __filemap_get_folio(mapping, lstart >> PAGE_SHIFT, FGP_LOCK, 0);
368 if (!IS_ERR(folio)) {
369 same_folio = lend < folio_pos(folio) + folio_size(folio);
370 if (!truncate_inode_partial_folio(folio, lstart, lend)) {
371 start = folio_next_index(folio);
372 if (same_folio)
373 end = folio->index;
374 }
375 folio_unlock(folio);
376 folio_put(folio);
377 folio = NULL;
378 }
379
380 if (!same_folio) {
381 folio = __filemap_get_folio(mapping, lend >> PAGE_SHIFT,
382 FGP_LOCK, 0);
383 if (!IS_ERR(folio)) {
384 if (!truncate_inode_partial_folio(folio, lstart, lend))
385 end = folio->index;
386 folio_unlock(folio);
387 folio_put(folio);
388 }
389 }
390
391 index = start;
392 while (index < end) {
393 cond_resched();
394 if (!find_get_entries(mapping, &index, end - 1, &fbatch,
395 indices)) {
396 /* If all gone from start onwards, we're done */
397 if (index == start)
398 break;
399 /* Otherwise restart to make sure all gone */
400 index = start;
401 continue;
402 }
403
404 for (i = 0; i < folio_batch_count(&fbatch); i++) {
405 struct folio *folio = fbatch.folios[i];
406
407 /* We rely upon deletion not changing page->index */
408
409 if (xa_is_value(folio))
410 continue;
411
412 folio_lock(folio);
413 VM_BUG_ON_FOLIO(!folio_contains(folio, indices[i]), folio);
414 folio_wait_writeback(folio);
415 truncate_inode_folio(mapping, folio);
416 folio_unlock(folio);
417 }
418 truncate_folio_batch_exceptionals(mapping, &fbatch, indices);
419 folio_batch_release(&fbatch);
420 }
421}
422EXPORT_SYMBOL(truncate_inode_pages_range);
423
424/**
425 * truncate_inode_pages - truncate *all* the pages from an offset
426 * @mapping: mapping to truncate
427 * @lstart: offset from which to truncate
428 *
429 * Called under (and serialised by) inode->i_rwsem and
430 * mapping->invalidate_lock.
431 *
432 * Note: When this function returns, there can be a page in the process of
433 * deletion (inside __filemap_remove_folio()) in the specified range. Thus
434 * mapping->nrpages can be non-zero when this function returns even after
435 * truncation of the whole mapping.
436 */
437void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
438{
439 truncate_inode_pages_range(mapping, lstart, (loff_t)-1);
440}
441EXPORT_SYMBOL(truncate_inode_pages);
442
443/**
444 * truncate_inode_pages_final - truncate *all* pages before inode dies
445 * @mapping: mapping to truncate
446 *
447 * Called under (and serialized by) inode->i_rwsem.
448 *
449 * Filesystems have to use this in the .evict_inode path to inform the
450 * VM that this is the final truncate and the inode is going away.
451 */
452void truncate_inode_pages_final(struct address_space *mapping)
453{
454 /*
455 * Page reclaim can not participate in regular inode lifetime
456 * management (can't call iput()) and thus can race with the
457 * inode teardown. Tell it when the address space is exiting,
458 * so that it does not install eviction information after the
459 * final truncate has begun.
460 */
461 mapping_set_exiting(mapping);
462
463 if (!mapping_empty(mapping)) {
464 /*
465 * As truncation uses a lockless tree lookup, cycle
466 * the tree lock to make sure any ongoing tree
467 * modification that does not see AS_EXITING is
468 * completed before starting the final truncate.
469 */
470 xa_lock_irq(&mapping->i_pages);
471 xa_unlock_irq(&mapping->i_pages);
472 }
473
474 truncate_inode_pages(mapping, 0);
475}
476EXPORT_SYMBOL(truncate_inode_pages_final);
477
478/**
479 * mapping_try_invalidate - Invalidate all the evictable folios of one inode
480 * @mapping: the address_space which holds the folios to invalidate
481 * @start: the offset 'from' which to invalidate
482 * @end: the offset 'to' which to invalidate (inclusive)
483 * @nr_failed: How many folio invalidations failed
484 *
485 * This function is similar to invalidate_mapping_pages(), except that it
486 * returns the number of folios which could not be evicted in @nr_failed.
487 */
488unsigned long mapping_try_invalidate(struct address_space *mapping,
489 pgoff_t start, pgoff_t end, unsigned long *nr_failed)
490{
491 pgoff_t indices[PAGEVEC_SIZE];
492 struct folio_batch fbatch;
493 pgoff_t index = start;
494 unsigned long ret;
495 unsigned long count = 0;
496 int i;
497
498 folio_batch_init(&fbatch);
499 while (find_lock_entries(mapping, &index, end, &fbatch, indices)) {
500 for (i = 0; i < folio_batch_count(&fbatch); i++) {
501 struct folio *folio = fbatch.folios[i];
502
503 /* We rely upon deletion not changing folio->index */
504
505 if (xa_is_value(folio)) {
506 count += invalidate_exceptional_entry(mapping,
507 indices[i], folio);
508 continue;
509 }
510
511 ret = mapping_evict_folio(mapping, folio);
512 folio_unlock(folio);
513 /*
514 * Invalidation is a hint that the folio is no longer
515 * of interest and try to speed up its reclaim.
516 */
517 if (!ret) {
518 deactivate_file_folio(folio);
519 /* Likely in the lru cache of a remote CPU */
520 if (nr_failed)
521 (*nr_failed)++;
522 }
523 count += ret;
524 }
525 folio_batch_remove_exceptionals(&fbatch);
526 folio_batch_release(&fbatch);
527 cond_resched();
528 }
529 return count;
530}
531
532/**
533 * invalidate_mapping_pages - Invalidate all clean, unlocked cache of one inode
534 * @mapping: the address_space which holds the cache to invalidate
535 * @start: the offset 'from' which to invalidate
536 * @end: the offset 'to' which to invalidate (inclusive)
537 *
538 * This function removes pages that are clean, unmapped and unlocked,
539 * as well as shadow entries. It will not block on IO activity.
540 *
541 * If you want to remove all the pages of one inode, regardless of
542 * their use and writeback state, use truncate_inode_pages().
543 *
544 * Return: The number of indices that had their contents invalidated
545 */
546unsigned long invalidate_mapping_pages(struct address_space *mapping,
547 pgoff_t start, pgoff_t end)
548{
549 return mapping_try_invalidate(mapping, start, end, NULL);
550}
551EXPORT_SYMBOL(invalidate_mapping_pages);
552
553/*
554 * This is like mapping_evict_folio(), except it ignores the folio's
555 * refcount. We do this because invalidate_inode_pages2() needs stronger
556 * invalidation guarantees, and cannot afford to leave folios behind because
557 * shrink_page_list() has a temp ref on them, or because they're transiently
558 * sitting in the folio_add_lru() caches.
559 */
560static int invalidate_complete_folio2(struct address_space *mapping,
561 struct folio *folio)
562{
563 if (folio->mapping != mapping)
564 return 0;
565
566 if (!filemap_release_folio(folio, GFP_KERNEL))
567 return 0;
568
569 spin_lock(&mapping->host->i_lock);
570 xa_lock_irq(&mapping->i_pages);
571 if (folio_test_dirty(folio))
572 goto failed;
573
574 BUG_ON(folio_has_private(folio));
575 __filemap_remove_folio(folio, NULL);
576 xa_unlock_irq(&mapping->i_pages);
577 if (mapping_shrinkable(mapping))
578 inode_add_lru(mapping->host);
579 spin_unlock(&mapping->host->i_lock);
580
581 filemap_free_folio(mapping, folio);
582 return 1;
583failed:
584 xa_unlock_irq(&mapping->i_pages);
585 spin_unlock(&mapping->host->i_lock);
586 return 0;
587}
588
589static int folio_launder(struct address_space *mapping, struct folio *folio)
590{
591 if (!folio_test_dirty(folio))
592 return 0;
593 if (folio->mapping != mapping || mapping->a_ops->launder_folio == NULL)
594 return 0;
595 return mapping->a_ops->launder_folio(folio);
596}
597
598/**
599 * invalidate_inode_pages2_range - remove range of pages from an address_space
600 * @mapping: the address_space
601 * @start: the page offset 'from' which to invalidate
602 * @end: the page offset 'to' which to invalidate (inclusive)
603 *
604 * Any pages which are found to be mapped into pagetables are unmapped prior to
605 * invalidation.
606 *
607 * Return: -EBUSY if any pages could not be invalidated.
608 */
609int invalidate_inode_pages2_range(struct address_space *mapping,
610 pgoff_t start, pgoff_t end)
611{
612 pgoff_t indices[PAGEVEC_SIZE];
613 struct folio_batch fbatch;
614 pgoff_t index;
615 int i;
616 int ret = 0;
617 int ret2 = 0;
618 int did_range_unmap = 0;
619
620 if (mapping_empty(mapping))
621 return 0;
622
623 folio_batch_init(&fbatch);
624 index = start;
625 while (find_get_entries(mapping, &index, end, &fbatch, indices)) {
626 for (i = 0; i < folio_batch_count(&fbatch); i++) {
627 struct folio *folio = fbatch.folios[i];
628
629 /* We rely upon deletion not changing folio->index */
630
631 if (xa_is_value(folio)) {
632 if (!invalidate_exceptional_entry2(mapping,
633 indices[i], folio))
634 ret = -EBUSY;
635 continue;
636 }
637
638 if (!did_range_unmap && folio_mapped(folio)) {
639 /*
640 * If folio is mapped, before taking its lock,
641 * zap the rest of the file in one hit.
642 */
643 unmap_mapping_pages(mapping, indices[i],
644 (1 + end - indices[i]), false);
645 did_range_unmap = 1;
646 }
647
648 folio_lock(folio);
649 if (unlikely(folio->mapping != mapping)) {
650 folio_unlock(folio);
651 continue;
652 }
653 VM_BUG_ON_FOLIO(!folio_contains(folio, indices[i]), folio);
654 folio_wait_writeback(folio);
655
656 if (folio_mapped(folio))
657 unmap_mapping_folio(folio);
658 BUG_ON(folio_mapped(folio));
659
660 ret2 = folio_launder(mapping, folio);
661 if (ret2 == 0) {
662 if (!invalidate_complete_folio2(mapping, folio))
663 ret2 = -EBUSY;
664 }
665 if (ret2 < 0)
666 ret = ret2;
667 folio_unlock(folio);
668 }
669 folio_batch_remove_exceptionals(&fbatch);
670 folio_batch_release(&fbatch);
671 cond_resched();
672 }
673 /*
674 * For DAX we invalidate page tables after invalidating page cache. We
675 * could invalidate page tables while invalidating each entry however
676 * that would be expensive. And doing range unmapping before doesn't
677 * work as we have no cheap way to find whether page cache entry didn't
678 * get remapped later.
679 */
680 if (dax_mapping(mapping)) {
681 unmap_mapping_pages(mapping, start, end - start + 1, false);
682 }
683 return ret;
684}
685EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
686
687/**
688 * invalidate_inode_pages2 - remove all pages from an address_space
689 * @mapping: the address_space
690 *
691 * Any pages which are found to be mapped into pagetables are unmapped prior to
692 * invalidation.
693 *
694 * Return: -EBUSY if any pages could not be invalidated.
695 */
696int invalidate_inode_pages2(struct address_space *mapping)
697{
698 return invalidate_inode_pages2_range(mapping, 0, -1);
699}
700EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
701
702/**
703 * truncate_pagecache - unmap and remove pagecache that has been truncated
704 * @inode: inode
705 * @newsize: new file size
706 *
707 * inode's new i_size must already be written before truncate_pagecache
708 * is called.
709 *
710 * This function should typically be called before the filesystem
711 * releases resources associated with the freed range (eg. deallocates
712 * blocks). This way, pagecache will always stay logically coherent
713 * with on-disk format, and the filesystem would not have to deal with
714 * situations such as writepage being called for a page that has already
715 * had its underlying blocks deallocated.
716 */
717void truncate_pagecache(struct inode *inode, loff_t newsize)
718{
719 struct address_space *mapping = inode->i_mapping;
720 loff_t holebegin = round_up(newsize, PAGE_SIZE);
721
722 /*
723 * unmap_mapping_range is called twice, first simply for
724 * efficiency so that truncate_inode_pages does fewer
725 * single-page unmaps. However after this first call, and
726 * before truncate_inode_pages finishes, it is possible for
727 * private pages to be COWed, which remain after
728 * truncate_inode_pages finishes, hence the second
729 * unmap_mapping_range call must be made for correctness.
730 */
731 unmap_mapping_range(mapping, holebegin, 0, 1);
732 truncate_inode_pages(mapping, newsize);
733 unmap_mapping_range(mapping, holebegin, 0, 1);
734}
735EXPORT_SYMBOL(truncate_pagecache);
736
737/**
738 * truncate_setsize - update inode and pagecache for a new file size
739 * @inode: inode
740 * @newsize: new file size
741 *
742 * truncate_setsize updates i_size and performs pagecache truncation (if
743 * necessary) to @newsize. It will be typically be called from the filesystem's
744 * setattr function when ATTR_SIZE is passed in.
745 *
746 * Must be called with a lock serializing truncates and writes (generally
747 * i_rwsem but e.g. xfs uses a different lock) and before all filesystem
748 * specific block truncation has been performed.
749 */
750void truncate_setsize(struct inode *inode, loff_t newsize)
751{
752 loff_t oldsize = inode->i_size;
753
754 i_size_write(inode, newsize);
755 if (newsize > oldsize)
756 pagecache_isize_extended(inode, oldsize, newsize);
757 truncate_pagecache(inode, newsize);
758}
759EXPORT_SYMBOL(truncate_setsize);
760
761/**
762 * pagecache_isize_extended - update pagecache after extension of i_size
763 * @inode: inode for which i_size was extended
764 * @from: original inode size
765 * @to: new inode size
766 *
767 * Handle extension of inode size either caused by extending truncate or by
768 * write starting after current i_size. We mark the page straddling current
769 * i_size RO so that page_mkwrite() is called on the nearest write access to
770 * the page. This way filesystem can be sure that page_mkwrite() is called on
771 * the page before user writes to the page via mmap after the i_size has been
772 * changed.
773 *
774 * The function must be called after i_size is updated so that page fault
775 * coming after we unlock the page will already see the new i_size.
776 * The function must be called while we still hold i_rwsem - this not only
777 * makes sure i_size is stable but also that userspace cannot observe new
778 * i_size value before we are prepared to store mmap writes at new inode size.
779 */
780void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to)
781{
782 int bsize = i_blocksize(inode);
783 loff_t rounded_from;
784 struct page *page;
785 pgoff_t index;
786
787 WARN_ON(to > inode->i_size);
788
789 if (from >= to || bsize == PAGE_SIZE)
790 return;
791 /* Page straddling @from will not have any hole block created? */
792 rounded_from = round_up(from, bsize);
793 if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1)))
794 return;
795
796 index = from >> PAGE_SHIFT;
797 page = find_lock_page(inode->i_mapping, index);
798 /* Page not cached? Nothing to do */
799 if (!page)
800 return;
801 /*
802 * See clear_page_dirty_for_io() for details why set_page_dirty()
803 * is needed.
804 */
805 if (page_mkclean(page))
806 set_page_dirty(page);
807 unlock_page(page);
808 put_page(page);
809}
810EXPORT_SYMBOL(pagecache_isize_extended);
811
812/**
813 * truncate_pagecache_range - unmap and remove pagecache that is hole-punched
814 * @inode: inode
815 * @lstart: offset of beginning of hole
816 * @lend: offset of last byte of hole
817 *
818 * This function should typically be called before the filesystem
819 * releases resources associated with the freed range (eg. deallocates
820 * blocks). This way, pagecache will always stay logically coherent
821 * with on-disk format, and the filesystem would not have to deal with
822 * situations such as writepage being called for a page that has already
823 * had its underlying blocks deallocated.
824 */
825void truncate_pagecache_range(struct inode *inode, loff_t lstart, loff_t lend)
826{
827 struct address_space *mapping = inode->i_mapping;
828 loff_t unmap_start = round_up(lstart, PAGE_SIZE);
829 loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1;
830 /*
831 * This rounding is currently just for example: unmap_mapping_range
832 * expands its hole outwards, whereas we want it to contract the hole
833 * inwards. However, existing callers of truncate_pagecache_range are
834 * doing their own page rounding first. Note that unmap_mapping_range
835 * allows holelen 0 for all, and we allow lend -1 for end of file.
836 */
837
838 /*
839 * Unlike in truncate_pagecache, unmap_mapping_range is called only
840 * once (before truncating pagecache), and without "even_cows" flag:
841 * hole-punching should not remove private COWed pages from the hole.
842 */
843 if ((u64)unmap_end > (u64)unmap_start)
844 unmap_mapping_range(mapping, unmap_start,
845 1 + unmap_end - unmap_start, 0);
846 truncate_inode_pages_range(mapping, lstart, lend);
847}
848EXPORT_SYMBOL(truncate_pagecache_range);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * mm/truncate.c - code for taking down pages from address_spaces
4 *
5 * Copyright (C) 2002, Linus Torvalds
6 *
7 * 10Sep2002 Andrew Morton
8 * Initial version.
9 */
10
11#include <linux/kernel.h>
12#include <linux/backing-dev.h>
13#include <linux/dax.h>
14#include <linux/gfp.h>
15#include <linux/mm.h>
16#include <linux/swap.h>
17#include <linux/export.h>
18#include <linux/pagemap.h>
19#include <linux/highmem.h>
20#include <linux/pagevec.h>
21#include <linux/task_io_accounting_ops.h>
22#include <linux/shmem_fs.h>
23#include <linux/rmap.h>
24#include "internal.h"
25
26static void clear_shadow_entries(struct address_space *mapping,
27 unsigned long start, unsigned long max)
28{
29 XA_STATE(xas, &mapping->i_pages, start);
30 struct folio *folio;
31
32 /* Handled by shmem itself, or for DAX we do nothing. */
33 if (shmem_mapping(mapping) || dax_mapping(mapping))
34 return;
35
36 xas_set_update(&xas, workingset_update_node);
37
38 spin_lock(&mapping->host->i_lock);
39 xas_lock_irq(&xas);
40
41 /* Clear all shadow entries from start to max */
42 xas_for_each(&xas, folio, max) {
43 if (xa_is_value(folio))
44 xas_store(&xas, NULL);
45 }
46
47 xas_unlock_irq(&xas);
48 if (mapping_shrinkable(mapping))
49 inode_add_lru(mapping->host);
50 spin_unlock(&mapping->host->i_lock);
51}
52
53/*
54 * Unconditionally remove exceptional entries. Usually called from truncate
55 * path. Note that the folio_batch may be altered by this function by removing
56 * exceptional entries similar to what folio_batch_remove_exceptionals() does.
57 * Please note that indices[] has entries in ascending order as guaranteed by
58 * either find_get_entries() or find_lock_entries().
59 */
60static void truncate_folio_batch_exceptionals(struct address_space *mapping,
61 struct folio_batch *fbatch, pgoff_t *indices)
62{
63 XA_STATE(xas, &mapping->i_pages, indices[0]);
64 int nr = folio_batch_count(fbatch);
65 struct folio *folio;
66 int i, j;
67
68 /* Handled by shmem itself */
69 if (shmem_mapping(mapping))
70 return;
71
72 for (j = 0; j < nr; j++)
73 if (xa_is_value(fbatch->folios[j]))
74 break;
75
76 if (j == nr)
77 return;
78
79 if (dax_mapping(mapping)) {
80 for (i = j; i < nr; i++) {
81 if (xa_is_value(fbatch->folios[i]))
82 dax_delete_mapping_entry(mapping, indices[i]);
83 }
84 goto out;
85 }
86
87 xas_set(&xas, indices[j]);
88 xas_set_update(&xas, workingset_update_node);
89
90 spin_lock(&mapping->host->i_lock);
91 xas_lock_irq(&xas);
92
93 xas_for_each(&xas, folio, indices[nr-1]) {
94 if (xa_is_value(folio))
95 xas_store(&xas, NULL);
96 }
97
98 xas_unlock_irq(&xas);
99 if (mapping_shrinkable(mapping))
100 inode_add_lru(mapping->host);
101 spin_unlock(&mapping->host->i_lock);
102out:
103 folio_batch_remove_exceptionals(fbatch);
104}
105
106/**
107 * folio_invalidate - Invalidate part or all of a folio.
108 * @folio: The folio which is affected.
109 * @offset: start of the range to invalidate
110 * @length: length of the range to invalidate
111 *
112 * folio_invalidate() is called when all or part of the folio has become
113 * invalidated by a truncate operation.
114 *
115 * folio_invalidate() does not have to release all buffers, but it must
116 * ensure that no dirty buffer is left outside @offset and that no I/O
117 * is underway against any of the blocks which are outside the truncation
118 * point. Because the caller is about to free (and possibly reuse) those
119 * blocks on-disk.
120 */
121void folio_invalidate(struct folio *folio, size_t offset, size_t length)
122{
123 const struct address_space_operations *aops = folio->mapping->a_ops;
124
125 if (aops->invalidate_folio)
126 aops->invalidate_folio(folio, offset, length);
127}
128EXPORT_SYMBOL_GPL(folio_invalidate);
129
130/*
131 * If truncate cannot remove the fs-private metadata from the page, the page
132 * becomes orphaned. It will be left on the LRU and may even be mapped into
133 * user pagetables if we're racing with filemap_fault().
134 *
135 * We need to bail out if page->mapping is no longer equal to the original
136 * mapping. This happens a) when the VM reclaimed the page while we waited on
137 * its lock, b) when a concurrent invalidate_mapping_pages got there first and
138 * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
139 */
140static void truncate_cleanup_folio(struct folio *folio)
141{
142 if (folio_mapped(folio))
143 unmap_mapping_folio(folio);
144
145 if (folio_needs_release(folio))
146 folio_invalidate(folio, 0, folio_size(folio));
147
148 /*
149 * Some filesystems seem to re-dirty the page even after
150 * the VM has canceled the dirty bit (eg ext3 journaling).
151 * Hence dirty accounting check is placed after invalidation.
152 */
153 folio_cancel_dirty(folio);
154}
155
156int truncate_inode_folio(struct address_space *mapping, struct folio *folio)
157{
158 if (folio->mapping != mapping)
159 return -EIO;
160
161 truncate_cleanup_folio(folio);
162 filemap_remove_folio(folio);
163 return 0;
164}
165
166/*
167 * Handle partial folios. The folio may be entirely within the
168 * range if a split has raced with us. If not, we zero the part of the
169 * folio that's within the [start, end] range, and then split the folio if
170 * it's large. split_page_range() will discard pages which now lie beyond
171 * i_size, and we rely on the caller to discard pages which lie within a
172 * newly created hole.
173 *
174 * Returns false if splitting failed so the caller can avoid
175 * discarding the entire folio which is stubbornly unsplit.
176 */
177bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end)
178{
179 loff_t pos = folio_pos(folio);
180 unsigned int offset, length;
181
182 if (pos < start)
183 offset = start - pos;
184 else
185 offset = 0;
186 length = folio_size(folio);
187 if (pos + length <= (u64)end)
188 length = length - offset;
189 else
190 length = end + 1 - pos - offset;
191
192 folio_wait_writeback(folio);
193 if (length == folio_size(folio)) {
194 truncate_inode_folio(folio->mapping, folio);
195 return true;
196 }
197
198 /*
199 * We may be zeroing pages we're about to discard, but it avoids
200 * doing a complex calculation here, and then doing the zeroing
201 * anyway if the page split fails.
202 */
203 if (!mapping_inaccessible(folio->mapping))
204 folio_zero_range(folio, offset, length);
205
206 if (folio_needs_release(folio))
207 folio_invalidate(folio, offset, length);
208 if (!folio_test_large(folio))
209 return true;
210 if (split_folio(folio) == 0)
211 return true;
212 if (folio_test_dirty(folio))
213 return false;
214 truncate_inode_folio(folio->mapping, folio);
215 return true;
216}
217
218/*
219 * Used to get rid of pages on hardware memory corruption.
220 */
221int generic_error_remove_folio(struct address_space *mapping,
222 struct folio *folio)
223{
224 if (!mapping)
225 return -EINVAL;
226 /*
227 * Only punch for normal data pages for now.
228 * Handling other types like directories would need more auditing.
229 */
230 if (!S_ISREG(mapping->host->i_mode))
231 return -EIO;
232 return truncate_inode_folio(mapping, folio);
233}
234EXPORT_SYMBOL(generic_error_remove_folio);
235
236/**
237 * mapping_evict_folio() - Remove an unused folio from the page-cache.
238 * @mapping: The mapping this folio belongs to.
239 * @folio: The folio to remove.
240 *
241 * Safely remove one folio from the page cache.
242 * It only drops clean, unused folios.
243 *
244 * Context: Folio must be locked.
245 * Return: The number of pages successfully removed.
246 */
247long mapping_evict_folio(struct address_space *mapping, struct folio *folio)
248{
249 /* The page may have been truncated before it was locked */
250 if (!mapping)
251 return 0;
252 if (folio_test_dirty(folio) || folio_test_writeback(folio))
253 return 0;
254 /* The refcount will be elevated if any page in the folio is mapped */
255 if (folio_ref_count(folio) >
256 folio_nr_pages(folio) + folio_has_private(folio) + 1)
257 return 0;
258 if (!filemap_release_folio(folio, 0))
259 return 0;
260
261 return remove_mapping(mapping, folio);
262}
263
264/**
265 * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets
266 * @mapping: mapping to truncate
267 * @lstart: offset from which to truncate
268 * @lend: offset to which to truncate (inclusive)
269 *
270 * Truncate the page cache, removing the pages that are between
271 * specified offsets (and zeroing out partial pages
272 * if lstart or lend + 1 is not page aligned).
273 *
274 * Truncate takes two passes - the first pass is nonblocking. It will not
275 * block on page locks and it will not block on writeback. The second pass
276 * will wait. This is to prevent as much IO as possible in the affected region.
277 * The first pass will remove most pages, so the search cost of the second pass
278 * is low.
279 *
280 * We pass down the cache-hot hint to the page freeing code. Even if the
281 * mapping is large, it is probably the case that the final pages are the most
282 * recently touched, and freeing happens in ascending file offset order.
283 *
284 * Note that since ->invalidate_folio() accepts range to invalidate
285 * truncate_inode_pages_range is able to handle cases where lend + 1 is not
286 * page aligned properly.
287 */
288void truncate_inode_pages_range(struct address_space *mapping,
289 loff_t lstart, loff_t lend)
290{
291 pgoff_t start; /* inclusive */
292 pgoff_t end; /* exclusive */
293 struct folio_batch fbatch;
294 pgoff_t indices[PAGEVEC_SIZE];
295 pgoff_t index;
296 int i;
297 struct folio *folio;
298 bool same_folio;
299
300 if (mapping_empty(mapping))
301 return;
302
303 /*
304 * 'start' and 'end' always covers the range of pages to be fully
305 * truncated. Partial pages are covered with 'partial_start' at the
306 * start of the range and 'partial_end' at the end of the range.
307 * Note that 'end' is exclusive while 'lend' is inclusive.
308 */
309 start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
310 if (lend == -1)
311 /*
312 * lend == -1 indicates end-of-file so we have to set 'end'
313 * to the highest possible pgoff_t and since the type is
314 * unsigned we're using -1.
315 */
316 end = -1;
317 else
318 end = (lend + 1) >> PAGE_SHIFT;
319
320 folio_batch_init(&fbatch);
321 index = start;
322 while (index < end && find_lock_entries(mapping, &index, end - 1,
323 &fbatch, indices)) {
324 truncate_folio_batch_exceptionals(mapping, &fbatch, indices);
325 for (i = 0; i < folio_batch_count(&fbatch); i++)
326 truncate_cleanup_folio(fbatch.folios[i]);
327 delete_from_page_cache_batch(mapping, &fbatch);
328 for (i = 0; i < folio_batch_count(&fbatch); i++)
329 folio_unlock(fbatch.folios[i]);
330 folio_batch_release(&fbatch);
331 cond_resched();
332 }
333
334 same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT);
335 folio = __filemap_get_folio(mapping, lstart >> PAGE_SHIFT, FGP_LOCK, 0);
336 if (!IS_ERR(folio)) {
337 same_folio = lend < folio_pos(folio) + folio_size(folio);
338 if (!truncate_inode_partial_folio(folio, lstart, lend)) {
339 start = folio_next_index(folio);
340 if (same_folio)
341 end = folio->index;
342 }
343 folio_unlock(folio);
344 folio_put(folio);
345 folio = NULL;
346 }
347
348 if (!same_folio) {
349 folio = __filemap_get_folio(mapping, lend >> PAGE_SHIFT,
350 FGP_LOCK, 0);
351 if (!IS_ERR(folio)) {
352 if (!truncate_inode_partial_folio(folio, lstart, lend))
353 end = folio->index;
354 folio_unlock(folio);
355 folio_put(folio);
356 }
357 }
358
359 index = start;
360 while (index < end) {
361 cond_resched();
362 if (!find_get_entries(mapping, &index, end - 1, &fbatch,
363 indices)) {
364 /* If all gone from start onwards, we're done */
365 if (index == start)
366 break;
367 /* Otherwise restart to make sure all gone */
368 index = start;
369 continue;
370 }
371
372 for (i = 0; i < folio_batch_count(&fbatch); i++) {
373 struct folio *folio = fbatch.folios[i];
374
375 /* We rely upon deletion not changing page->index */
376
377 if (xa_is_value(folio))
378 continue;
379
380 folio_lock(folio);
381 VM_BUG_ON_FOLIO(!folio_contains(folio, indices[i]), folio);
382 folio_wait_writeback(folio);
383 truncate_inode_folio(mapping, folio);
384 folio_unlock(folio);
385 }
386 truncate_folio_batch_exceptionals(mapping, &fbatch, indices);
387 folio_batch_release(&fbatch);
388 }
389}
390EXPORT_SYMBOL(truncate_inode_pages_range);
391
392/**
393 * truncate_inode_pages - truncate *all* the pages from an offset
394 * @mapping: mapping to truncate
395 * @lstart: offset from which to truncate
396 *
397 * Called under (and serialised by) inode->i_rwsem and
398 * mapping->invalidate_lock.
399 *
400 * Note: When this function returns, there can be a page in the process of
401 * deletion (inside __filemap_remove_folio()) in the specified range. Thus
402 * mapping->nrpages can be non-zero when this function returns even after
403 * truncation of the whole mapping.
404 */
405void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
406{
407 truncate_inode_pages_range(mapping, lstart, (loff_t)-1);
408}
409EXPORT_SYMBOL(truncate_inode_pages);
410
411/**
412 * truncate_inode_pages_final - truncate *all* pages before inode dies
413 * @mapping: mapping to truncate
414 *
415 * Called under (and serialized by) inode->i_rwsem.
416 *
417 * Filesystems have to use this in the .evict_inode path to inform the
418 * VM that this is the final truncate and the inode is going away.
419 */
420void truncate_inode_pages_final(struct address_space *mapping)
421{
422 /*
423 * Page reclaim can not participate in regular inode lifetime
424 * management (can't call iput()) and thus can race with the
425 * inode teardown. Tell it when the address space is exiting,
426 * so that it does not install eviction information after the
427 * final truncate has begun.
428 */
429 mapping_set_exiting(mapping);
430
431 if (!mapping_empty(mapping)) {
432 /*
433 * As truncation uses a lockless tree lookup, cycle
434 * the tree lock to make sure any ongoing tree
435 * modification that does not see AS_EXITING is
436 * completed before starting the final truncate.
437 */
438 xa_lock_irq(&mapping->i_pages);
439 xa_unlock_irq(&mapping->i_pages);
440 }
441
442 truncate_inode_pages(mapping, 0);
443}
444EXPORT_SYMBOL(truncate_inode_pages_final);
445
446/**
447 * mapping_try_invalidate - Invalidate all the evictable folios of one inode
448 * @mapping: the address_space which holds the folios to invalidate
449 * @start: the offset 'from' which to invalidate
450 * @end: the offset 'to' which to invalidate (inclusive)
451 * @nr_failed: How many folio invalidations failed
452 *
453 * This function is similar to invalidate_mapping_pages(), except that it
454 * returns the number of folios which could not be evicted in @nr_failed.
455 */
456unsigned long mapping_try_invalidate(struct address_space *mapping,
457 pgoff_t start, pgoff_t end, unsigned long *nr_failed)
458{
459 pgoff_t indices[PAGEVEC_SIZE];
460 struct folio_batch fbatch;
461 pgoff_t index = start;
462 unsigned long ret;
463 unsigned long count = 0;
464 int i;
465
466 folio_batch_init(&fbatch);
467 while (find_lock_entries(mapping, &index, end, &fbatch, indices)) {
468 bool xa_has_values = false;
469 int nr = folio_batch_count(&fbatch);
470
471 for (i = 0; i < nr; i++) {
472 struct folio *folio = fbatch.folios[i];
473
474 /* We rely upon deletion not changing folio->index */
475
476 if (xa_is_value(folio)) {
477 xa_has_values = true;
478 count++;
479 continue;
480 }
481
482 ret = mapping_evict_folio(mapping, folio);
483 folio_unlock(folio);
484 /*
485 * Invalidation is a hint that the folio is no longer
486 * of interest and try to speed up its reclaim.
487 */
488 if (!ret) {
489 deactivate_file_folio(folio);
490 /* Likely in the lru cache of a remote CPU */
491 if (nr_failed)
492 (*nr_failed)++;
493 }
494 count += ret;
495 }
496
497 if (xa_has_values)
498 clear_shadow_entries(mapping, indices[0], indices[nr-1]);
499
500 folio_batch_remove_exceptionals(&fbatch);
501 folio_batch_release(&fbatch);
502 cond_resched();
503 }
504 return count;
505}
506
507/**
508 * invalidate_mapping_pages - Invalidate all clean, unlocked cache of one inode
509 * @mapping: the address_space which holds the cache to invalidate
510 * @start: the offset 'from' which to invalidate
511 * @end: the offset 'to' which to invalidate (inclusive)
512 *
513 * This function removes pages that are clean, unmapped and unlocked,
514 * as well as shadow entries. It will not block on IO activity.
515 *
516 * If you want to remove all the pages of one inode, regardless of
517 * their use and writeback state, use truncate_inode_pages().
518 *
519 * Return: The number of indices that had their contents invalidated
520 */
521unsigned long invalidate_mapping_pages(struct address_space *mapping,
522 pgoff_t start, pgoff_t end)
523{
524 return mapping_try_invalidate(mapping, start, end, NULL);
525}
526EXPORT_SYMBOL(invalidate_mapping_pages);
527
528/*
529 * This is like mapping_evict_folio(), except it ignores the folio's
530 * refcount. We do this because invalidate_inode_pages2() needs stronger
531 * invalidation guarantees, and cannot afford to leave folios behind because
532 * shrink_folio_list() has a temp ref on them, or because they're transiently
533 * sitting in the folio_add_lru() caches.
534 */
535static int invalidate_complete_folio2(struct address_space *mapping,
536 struct folio *folio)
537{
538 if (folio->mapping != mapping)
539 return 0;
540
541 if (!filemap_release_folio(folio, GFP_KERNEL))
542 return 0;
543
544 spin_lock(&mapping->host->i_lock);
545 xa_lock_irq(&mapping->i_pages);
546 if (folio_test_dirty(folio))
547 goto failed;
548
549 BUG_ON(folio_has_private(folio));
550 __filemap_remove_folio(folio, NULL);
551 xa_unlock_irq(&mapping->i_pages);
552 if (mapping_shrinkable(mapping))
553 inode_add_lru(mapping->host);
554 spin_unlock(&mapping->host->i_lock);
555
556 filemap_free_folio(mapping, folio);
557 return 1;
558failed:
559 xa_unlock_irq(&mapping->i_pages);
560 spin_unlock(&mapping->host->i_lock);
561 return 0;
562}
563
564static int folio_launder(struct address_space *mapping, struct folio *folio)
565{
566 if (!folio_test_dirty(folio))
567 return 0;
568 if (folio->mapping != mapping || mapping->a_ops->launder_folio == NULL)
569 return 0;
570 return mapping->a_ops->launder_folio(folio);
571}
572
573/**
574 * invalidate_inode_pages2_range - remove range of pages from an address_space
575 * @mapping: the address_space
576 * @start: the page offset 'from' which to invalidate
577 * @end: the page offset 'to' which to invalidate (inclusive)
578 *
579 * Any pages which are found to be mapped into pagetables are unmapped prior to
580 * invalidation.
581 *
582 * Return: -EBUSY if any pages could not be invalidated.
583 */
584int invalidate_inode_pages2_range(struct address_space *mapping,
585 pgoff_t start, pgoff_t end)
586{
587 pgoff_t indices[PAGEVEC_SIZE];
588 struct folio_batch fbatch;
589 pgoff_t index;
590 int i;
591 int ret = 0;
592 int ret2 = 0;
593 int did_range_unmap = 0;
594
595 if (mapping_empty(mapping))
596 return 0;
597
598 folio_batch_init(&fbatch);
599 index = start;
600 while (find_get_entries(mapping, &index, end, &fbatch, indices)) {
601 bool xa_has_values = false;
602 int nr = folio_batch_count(&fbatch);
603
604 for (i = 0; i < nr; i++) {
605 struct folio *folio = fbatch.folios[i];
606
607 /* We rely upon deletion not changing folio->index */
608
609 if (xa_is_value(folio)) {
610 xa_has_values = true;
611 if (dax_mapping(mapping) &&
612 !dax_invalidate_mapping_entry_sync(mapping, indices[i]))
613 ret = -EBUSY;
614 continue;
615 }
616
617 if (!did_range_unmap && folio_mapped(folio)) {
618 /*
619 * If folio is mapped, before taking its lock,
620 * zap the rest of the file in one hit.
621 */
622 unmap_mapping_pages(mapping, indices[i],
623 (1 + end - indices[i]), false);
624 did_range_unmap = 1;
625 }
626
627 folio_lock(folio);
628 if (unlikely(folio->mapping != mapping)) {
629 folio_unlock(folio);
630 continue;
631 }
632 VM_BUG_ON_FOLIO(!folio_contains(folio, indices[i]), folio);
633 folio_wait_writeback(folio);
634
635 if (folio_mapped(folio))
636 unmap_mapping_folio(folio);
637 BUG_ON(folio_mapped(folio));
638
639 ret2 = folio_launder(mapping, folio);
640 if (ret2 == 0) {
641 if (!invalidate_complete_folio2(mapping, folio))
642 ret2 = -EBUSY;
643 }
644 if (ret2 < 0)
645 ret = ret2;
646 folio_unlock(folio);
647 }
648
649 if (xa_has_values)
650 clear_shadow_entries(mapping, indices[0], indices[nr-1]);
651
652 folio_batch_remove_exceptionals(&fbatch);
653 folio_batch_release(&fbatch);
654 cond_resched();
655 }
656 /*
657 * For DAX we invalidate page tables after invalidating page cache. We
658 * could invalidate page tables while invalidating each entry however
659 * that would be expensive. And doing range unmapping before doesn't
660 * work as we have no cheap way to find whether page cache entry didn't
661 * get remapped later.
662 */
663 if (dax_mapping(mapping)) {
664 unmap_mapping_pages(mapping, start, end - start + 1, false);
665 }
666 return ret;
667}
668EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
669
670/**
671 * invalidate_inode_pages2 - remove all pages from an address_space
672 * @mapping: the address_space
673 *
674 * Any pages which are found to be mapped into pagetables are unmapped prior to
675 * invalidation.
676 *
677 * Return: -EBUSY if any pages could not be invalidated.
678 */
679int invalidate_inode_pages2(struct address_space *mapping)
680{
681 return invalidate_inode_pages2_range(mapping, 0, -1);
682}
683EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
684
685/**
686 * truncate_pagecache - unmap and remove pagecache that has been truncated
687 * @inode: inode
688 * @newsize: new file size
689 *
690 * inode's new i_size must already be written before truncate_pagecache
691 * is called.
692 *
693 * This function should typically be called before the filesystem
694 * releases resources associated with the freed range (eg. deallocates
695 * blocks). This way, pagecache will always stay logically coherent
696 * with on-disk format, and the filesystem would not have to deal with
697 * situations such as writepage being called for a page that has already
698 * had its underlying blocks deallocated.
699 */
700void truncate_pagecache(struct inode *inode, loff_t newsize)
701{
702 struct address_space *mapping = inode->i_mapping;
703 loff_t holebegin = round_up(newsize, PAGE_SIZE);
704
705 /*
706 * unmap_mapping_range is called twice, first simply for
707 * efficiency so that truncate_inode_pages does fewer
708 * single-page unmaps. However after this first call, and
709 * before truncate_inode_pages finishes, it is possible for
710 * private pages to be COWed, which remain after
711 * truncate_inode_pages finishes, hence the second
712 * unmap_mapping_range call must be made for correctness.
713 */
714 unmap_mapping_range(mapping, holebegin, 0, 1);
715 truncate_inode_pages(mapping, newsize);
716 unmap_mapping_range(mapping, holebegin, 0, 1);
717}
718EXPORT_SYMBOL(truncate_pagecache);
719
720/**
721 * truncate_setsize - update inode and pagecache for a new file size
722 * @inode: inode
723 * @newsize: new file size
724 *
725 * truncate_setsize updates i_size and performs pagecache truncation (if
726 * necessary) to @newsize. It will be typically be called from the filesystem's
727 * setattr function when ATTR_SIZE is passed in.
728 *
729 * Must be called with a lock serializing truncates and writes (generally
730 * i_rwsem but e.g. xfs uses a different lock) and before all filesystem
731 * specific block truncation has been performed.
732 */
733void truncate_setsize(struct inode *inode, loff_t newsize)
734{
735 loff_t oldsize = inode->i_size;
736
737 i_size_write(inode, newsize);
738 if (newsize > oldsize)
739 pagecache_isize_extended(inode, oldsize, newsize);
740 truncate_pagecache(inode, newsize);
741}
742EXPORT_SYMBOL(truncate_setsize);
743
744/**
745 * pagecache_isize_extended - update pagecache after extension of i_size
746 * @inode: inode for which i_size was extended
747 * @from: original inode size
748 * @to: new inode size
749 *
750 * Handle extension of inode size either caused by extending truncate or
751 * by write starting after current i_size. We mark the page straddling
752 * current i_size RO so that page_mkwrite() is called on the first
753 * write access to the page. The filesystem will update its per-block
754 * information before user writes to the page via mmap after the i_size
755 * has been changed.
756 *
757 * The function must be called after i_size is updated so that page fault
758 * coming after we unlock the folio will already see the new i_size.
759 * The function must be called while we still hold i_rwsem - this not only
760 * makes sure i_size is stable but also that userspace cannot observe new
761 * i_size value before we are prepared to store mmap writes at new inode size.
762 */
763void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to)
764{
765 int bsize = i_blocksize(inode);
766 loff_t rounded_from;
767 struct folio *folio;
768
769 WARN_ON(to > inode->i_size);
770
771 if (from >= to || bsize >= PAGE_SIZE)
772 return;
773 /* Page straddling @from will not have any hole block created? */
774 rounded_from = round_up(from, bsize);
775 if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1)))
776 return;
777
778 folio = filemap_lock_folio(inode->i_mapping, from / PAGE_SIZE);
779 /* Folio not cached? Nothing to do */
780 if (IS_ERR(folio))
781 return;
782 /*
783 * See folio_clear_dirty_for_io() for details why folio_mark_dirty()
784 * is needed.
785 */
786 if (folio_mkclean(folio))
787 folio_mark_dirty(folio);
788
789 /*
790 * The post-eof range of the folio must be zeroed before it is exposed
791 * to the file. Writeback normally does this, but since i_size has been
792 * increased we handle it here.
793 */
794 if (folio_test_dirty(folio)) {
795 unsigned int offset, end;
796
797 offset = from - folio_pos(folio);
798 end = min_t(unsigned int, to - folio_pos(folio),
799 folio_size(folio));
800 folio_zero_segment(folio, offset, end);
801 }
802
803 folio_unlock(folio);
804 folio_put(folio);
805}
806EXPORT_SYMBOL(pagecache_isize_extended);
807
808/**
809 * truncate_pagecache_range - unmap and remove pagecache that is hole-punched
810 * @inode: inode
811 * @lstart: offset of beginning of hole
812 * @lend: offset of last byte of hole
813 *
814 * This function should typically be called before the filesystem
815 * releases resources associated with the freed range (eg. deallocates
816 * blocks). This way, pagecache will always stay logically coherent
817 * with on-disk format, and the filesystem would not have to deal with
818 * situations such as writepage being called for a page that has already
819 * had its underlying blocks deallocated.
820 */
821void truncate_pagecache_range(struct inode *inode, loff_t lstart, loff_t lend)
822{
823 struct address_space *mapping = inode->i_mapping;
824 loff_t unmap_start = round_up(lstart, PAGE_SIZE);
825 loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1;
826 /*
827 * This rounding is currently just for example: unmap_mapping_range
828 * expands its hole outwards, whereas we want it to contract the hole
829 * inwards. However, existing callers of truncate_pagecache_range are
830 * doing their own page rounding first. Note that unmap_mapping_range
831 * allows holelen 0 for all, and we allow lend -1 for end of file.
832 */
833
834 /*
835 * Unlike in truncate_pagecache, unmap_mapping_range is called only
836 * once (before truncating pagecache), and without "even_cows" flag:
837 * hole-punching should not remove private COWed pages from the hole.
838 */
839 if ((u64)unmap_end > (u64)unmap_start)
840 unmap_mapping_range(mapping, unmap_start,
841 1 + unmap_end - unmap_start, 0);
842 truncate_inode_pages_range(mapping, lstart, lend);
843}
844EXPORT_SYMBOL(truncate_pagecache_range);