truncate.c

  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_lru_list_add(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				/*
 83				 * File systems should already have called
 84				 * dax_break_layout_entry() to remove all DAX
 85				 * entries while holding a lock to prevent
 86				 * establishing new entries. Therefore we
 87				 * shouldn't find any here.
 88				 */
 89				WARN_ON_ONCE(1);
 90
 91				/*
 92				 * Delete the mapping so truncate_pagecache()
 93				 * doesn't loop forever.
 94				 */
 95				dax_delete_mapping_entry(mapping, indices[i]);
 96			}
 97		}
 98		goto out;
 99	}
100
101	xas_set(&xas, indices[j]);
102	xas_set_update(&xas, workingset_update_node);
103
104	spin_lock(&mapping->host->i_lock);
105	xas_lock_irq(&xas);
106
107	xas_for_each(&xas, folio, indices[nr-1]) {
108		if (xa_is_value(folio))
109			xas_store(&xas, NULL);
110	}
111
112	xas_unlock_irq(&xas);
113	if (mapping_shrinkable(mapping))
114		inode_lru_list_add(mapping->host);
115	spin_unlock(&mapping->host->i_lock);
116out:
117	folio_batch_remove_exceptionals(fbatch);
118}
119
120/**
121 * folio_invalidate - Invalidate part or all of a folio.
122 * @folio: The folio which is affected.
123 * @offset: start of the range to invalidate
124 * @length: length of the range to invalidate
125 *
126 * folio_invalidate() is called when all or part of the folio has become
127 * invalidated by a truncate operation.
128 *
129 * folio_invalidate() does not have to release all buffers, but it must
130 * ensure that no dirty buffer is left outside @offset and that no I/O
131 * is underway against any of the blocks which are outside the truncation
132 * point.  Because the caller is about to free (and possibly reuse) those
133 * blocks on-disk.
134 */
135void folio_invalidate(struct folio *folio, size_t offset, size_t length)
136{
137	const struct address_space_operations *aops = folio->mapping->a_ops;
138
139	if (aops->invalidate_folio)
140		aops->invalidate_folio(folio, offset, length);
141}
142EXPORT_SYMBOL_GPL(folio_invalidate);
143
144/*
145 * If truncate cannot remove the fs-private metadata from the page, the page
146 * becomes orphaned.  It will be left on the LRU and may even be mapped into
147 * user pagetables if we're racing with filemap_fault().
148 *
149 * We need to bail out if page->mapping is no longer equal to the original
150 * mapping.  This happens a) when the VM reclaimed the page while we waited on
151 * its lock, b) when a concurrent invalidate_mapping_pages got there first and
152 * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
153 */
154static void truncate_cleanup_folio(struct folio *folio)
155{
156	if (folio_mapped(folio))
157		unmap_mapping_folio(folio);
158
159	if (folio_needs_release(folio))
160		folio_invalidate(folio, 0, folio_size(folio));
161
162	/*
163	 * Some filesystems seem to re-dirty the page even after
164	 * the VM has canceled the dirty bit (eg ext3 journaling).
165	 * Hence dirty accounting check is placed after invalidation.
166	 */
167	folio_cancel_dirty(folio);
168}
169
170int truncate_inode_folio(struct address_space *mapping, struct folio *folio)
171{
172	if (folio->mapping != mapping)
173		return -EIO;
174
175	truncate_cleanup_folio(folio);
176	filemap_remove_folio(folio);
177	return 0;
178}
179
180static int try_folio_split_or_unmap(struct folio *folio, struct page *split_at,
181				    unsigned long min_order)
182{
183	enum ttu_flags ttu_flags =
184		TTU_SYNC |
185		TTU_SPLIT_HUGE_PMD |
186		TTU_IGNORE_MLOCK;
187	int ret;
188
189	ret = try_folio_split_to_order(folio, split_at, min_order);
190
191	/*
192	 * If the split fails, unmap the folio, so it will be refaulted
193	 * with PTEs to respect SIGBUS semantics.
194	 *
195	 * Make an exception for shmem/tmpfs that for long time
196	 * intentionally mapped with PMDs across i_size.
197	 */
198	if (ret && !shmem_mapping(folio->mapping)) {
199		try_to_unmap(folio, ttu_flags);
200		WARN_ON(folio_mapped(folio));
201	}
202
203	return ret;
204}
205
206/*
207 * Handle partial folios.  The folio may be entirely within the
208 * range if a split has raced with us.  If not, we zero the part of the
209 * folio that's within the [start, end] range, and then split the folio if
210 * it's large.  split_page_range() will discard pages which now lie beyond
211 * i_size, and we rely on the caller to discard pages which lie within a
212 * newly created hole.
213 *
214 * Returns false if splitting failed so the caller can avoid
215 * discarding the entire folio which is stubbornly unsplit.
216 */
217bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end)
218{
219	loff_t pos = folio_pos(folio);
220	size_t size = folio_size(folio);
221	unsigned int offset, length;
222	struct page *split_at, *split_at2;
223	unsigned int min_order;
224
225	if (pos < start)
226		offset = start - pos;
227	else
228		offset = 0;
229	if (pos + size <= (u64)end)
230		length = size - offset;
231	else
232		length = end + 1 - pos - offset;
233
234	folio_wait_writeback(folio);
235	if (length == size) {
236		truncate_inode_folio(folio->mapping, folio);
237		return true;
238	}
239
240	/*
241	 * We may be zeroing pages we're about to discard, but it avoids
242	 * doing a complex calculation here, and then doing the zeroing
243	 * anyway if the page split fails.
244	 */
245	if (!mapping_inaccessible(folio->mapping))
246		folio_zero_range(folio, offset, length);
247
248	if (folio_needs_release(folio))
249		folio_invalidate(folio, offset, length);
250	if (!folio_test_large(folio))
251		return true;
252
253	min_order = mapping_min_folio_order(folio->mapping);
254	split_at = folio_page(folio, PAGE_ALIGN_DOWN(offset) / PAGE_SIZE);
255	if (!try_folio_split_or_unmap(folio, split_at, min_order)) {
256		/*
257		 * try to split at offset + length to make sure folios within
258		 * the range can be dropped, especially to avoid memory waste
259		 * for shmem truncate
260		 */
261		struct folio *folio2;
262
263		if (offset + length == size)
264			goto no_split;
265
266		split_at2 = folio_page(folio,
267				PAGE_ALIGN_DOWN(offset + length) / PAGE_SIZE);
268		folio2 = page_folio(split_at2);
269
270		if (!folio_try_get(folio2))
271			goto no_split;
272
273		if (!folio_test_large(folio2))
274			goto out;
275
276		if (!folio_trylock(folio2))
277			goto out;
278
279		/* make sure folio2 is large and does not change its mapping */
280		if (folio_test_large(folio2) &&
281		    folio2->mapping == folio->mapping)
282			try_folio_split_or_unmap(folio2, split_at2, min_order);
283
284		folio_unlock(folio2);
285out:
286		folio_put(folio2);
287no_split:
288		return true;
289	}
290	if (folio_test_dirty(folio))
291		return false;
292	truncate_inode_folio(folio->mapping, folio);
293	return true;
294}
295
296/*
297 * Used to get rid of pages on hardware memory corruption.
298 */
299int generic_error_remove_folio(struct address_space *mapping,
300		struct folio *folio)
301{
302	if (!mapping)
303		return -EINVAL;
304	/*
305	 * Only punch for normal data pages for now.
306	 * Handling other types like directories would need more auditing.
307	 */
308	if (!S_ISREG(mapping->host->i_mode))
309		return -EIO;
310	return truncate_inode_folio(mapping, folio);
311}
312EXPORT_SYMBOL(generic_error_remove_folio);
313
314/**
315 * mapping_evict_folio() - Remove an unused folio from the page-cache.
316 * @mapping: The mapping this folio belongs to.
317 * @folio: The folio to remove.
318 *
319 * Safely remove one folio from the page cache.
320 * It only drops clean, unused folios.
321 *
322 * Context: Folio must be locked.
323 * Return: The number of pages successfully removed.
324 */
325long mapping_evict_folio(struct address_space *mapping, struct folio *folio)
326{
327	/* The page may have been truncated before it was locked */
328	if (!mapping)
329		return 0;
330	if (folio_test_dirty(folio) || folio_test_writeback(folio))
331		return 0;
332	/* The refcount will be elevated if any page in the folio is mapped */
333	if (folio_ref_count(folio) >
334			folio_nr_pages(folio) + folio_has_private(folio) + 1)
335		return 0;
336	if (!filemap_release_folio(folio, 0))
337		return 0;
338
339	return remove_mapping(mapping, folio);
340}
341
342/**
343 * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets
344 * @mapping: mapping to truncate
345 * @lstart: offset from which to truncate
346 * @lend: offset to which to truncate (inclusive)
347 *
348 * Truncate the page cache, removing the pages that are between
349 * specified offsets (and zeroing out partial pages
350 * if lstart or lend + 1 is not page aligned).
351 *
352 * Truncate takes two passes - the first pass is nonblocking.  It will not
353 * block on page locks and it will not block on writeback.  The second pass
354 * will wait.  This is to prevent as much IO as possible in the affected region.
355 * The first pass will remove most pages, so the search cost of the second pass
356 * is low.
357 *
358 * We pass down the cache-hot hint to the page freeing code.  Even if the
359 * mapping is large, it is probably the case that the final pages are the most
360 * recently touched, and freeing happens in ascending file offset order.
361 *
362 * Note that since ->invalidate_folio() accepts range to invalidate
363 * truncate_inode_pages_range is able to handle cases where lend + 1 is not
364 * page aligned properly.
365 */
366void truncate_inode_pages_range(struct address_space *mapping,
367				loff_t lstart, uoff_t lend)
368{
369	pgoff_t		start;		/* inclusive */
370	pgoff_t		end;		/* exclusive */
371	struct folio_batch fbatch;
372	pgoff_t		indices[PAGEVEC_SIZE];
373	pgoff_t		index;
374	int		i;
375	struct folio	*folio;
376	bool		same_folio;
377
378	if (mapping_empty(mapping))
379		return;
380
381	/*
382	 * 'start' and 'end' always covers the range of pages to be fully
383	 * truncated. Partial pages are covered with 'partial_start' at the
384	 * start of the range and 'partial_end' at the end of the range.
385	 * Note that 'end' is exclusive while 'lend' is inclusive.
386	 */
387	start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
388	if (lend == -1)
389		/*
390		 * lend == -1 indicates end-of-file so we have to set 'end'
391		 * to the highest possible pgoff_t and since the type is
392		 * unsigned we're using -1.
393		 */
394		end = -1;
395	else
396		end = (lend + 1) >> PAGE_SHIFT;
397
398	folio_batch_init(&fbatch);
399	index = start;
400	while (index < end && find_lock_entries(mapping, &index, end - 1,
401			&fbatch, indices)) {
402		truncate_folio_batch_exceptionals(mapping, &fbatch, indices);
403		for (i = 0; i < folio_batch_count(&fbatch); i++)
404			truncate_cleanup_folio(fbatch.folios[i]);
405		delete_from_page_cache_batch(mapping, &fbatch);
406		for (i = 0; i < folio_batch_count(&fbatch); i++)
407			folio_unlock(fbatch.folios[i]);
408		folio_batch_release(&fbatch);
409		cond_resched();
410	}
411
412	same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT);
413	folio = __filemap_get_folio(mapping, lstart >> PAGE_SHIFT, FGP_LOCK, 0);
414	if (!IS_ERR(folio)) {
415		same_folio = lend < folio_next_pos(folio);
416		if (!truncate_inode_partial_folio(folio, lstart, lend)) {
417			start = folio_next_index(folio);
418			if (same_folio)
419				end = folio->index;
420		}
421		folio_unlock(folio);
422		folio_put(folio);
423		folio = NULL;
424	}
425
426	if (!same_folio) {
427		folio = __filemap_get_folio(mapping, lend >> PAGE_SHIFT,
428						FGP_LOCK, 0);
429		if (!IS_ERR(folio)) {
430			if (!truncate_inode_partial_folio(folio, lstart, lend))
431				end = folio->index;
432			folio_unlock(folio);
433			folio_put(folio);
434		}
435	}
436
437	index = start;
438	while (index < end) {
439		cond_resched();
440		if (!find_get_entries(mapping, &index, end - 1, &fbatch,
441				indices)) {
442			/* If all gone from start onwards, we're done */
443			if (index == start)
444				break;
445			/* Otherwise restart to make sure all gone */
446			index = start;
447			continue;
448		}
449
450		for (i = 0; i < folio_batch_count(&fbatch); i++) {
451			struct folio *folio = fbatch.folios[i];
452
453			/* We rely upon deletion not changing folio->index */
454
455			if (xa_is_value(folio))
456				continue;
457
458			folio_lock(folio);
459			VM_BUG_ON_FOLIO(!folio_contains(folio, indices[i]), folio);
460			folio_wait_writeback(folio);
461			truncate_inode_folio(mapping, folio);
462			folio_unlock(folio);
463		}
464		truncate_folio_batch_exceptionals(mapping, &fbatch, indices);
465		folio_batch_release(&fbatch);
466	}
467}
468EXPORT_SYMBOL(truncate_inode_pages_range);
469
470/**
471 * truncate_inode_pages - truncate *all* the pages from an offset
472 * @mapping: mapping to truncate
473 * @lstart: offset from which to truncate
474 *
475 * Called under (and serialised by) inode->i_rwsem and
476 * mapping->invalidate_lock.
477 *
478 * Note: When this function returns, there can be a page in the process of
479 * deletion (inside __filemap_remove_folio()) in the specified range.  Thus
480 * mapping->nrpages can be non-zero when this function returns even after
481 * truncation of the whole mapping.
482 */
483void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
484{
485	truncate_inode_pages_range(mapping, lstart, (loff_t)-1);
486}
487EXPORT_SYMBOL(truncate_inode_pages);
488
489/**
490 * truncate_inode_pages_final - truncate *all* pages before inode dies
491 * @mapping: mapping to truncate
492 *
493 * Called under (and serialized by) inode->i_rwsem.
494 *
495 * Filesystems have to use this in the .evict_inode path to inform the
496 * VM that this is the final truncate and the inode is going away.
497 */
498void truncate_inode_pages_final(struct address_space *mapping)
499{
500	/*
501	 * Page reclaim can not participate in regular inode lifetime
502	 * management (can't call iput()) and thus can race with the
503	 * inode teardown.  Tell it when the address space is exiting,
504	 * so that it does not install eviction information after the
505	 * final truncate has begun.
506	 */
507	mapping_set_exiting(mapping);
508
509	if (!mapping_empty(mapping)) {
510		/*
511		 * As truncation uses a lockless tree lookup, cycle
512		 * the tree lock to make sure any ongoing tree
513		 * modification that does not see AS_EXITING is
514		 * completed before starting the final truncate.
515		 */
516		xa_lock_irq(&mapping->i_pages);
517		xa_unlock_irq(&mapping->i_pages);
518	}
519
520	truncate_inode_pages(mapping, 0);
521}
522EXPORT_SYMBOL(truncate_inode_pages_final);
523
524/**
525 * mapping_try_invalidate - Invalidate all the evictable folios of one inode
526 * @mapping: the address_space which holds the folios to invalidate
527 * @start: the offset 'from' which to invalidate
528 * @end: the offset 'to' which to invalidate (inclusive)
529 * @nr_failed: How many folio invalidations failed
530 *
531 * This function is similar to invalidate_mapping_pages(), except that it
532 * returns the number of folios which could not be evicted in @nr_failed.
533 */
534unsigned long mapping_try_invalidate(struct address_space *mapping,
535		pgoff_t start, pgoff_t end, unsigned long *nr_failed)
536{
537	pgoff_t indices[PAGEVEC_SIZE];
538	struct folio_batch fbatch;
539	pgoff_t index = start;
540	unsigned long ret;
541	unsigned long count = 0;
542	int i;
543
544	folio_batch_init(&fbatch);
545	while (find_lock_entries(mapping, &index, end, &fbatch, indices)) {
546		bool xa_has_values = false;
547		int nr = folio_batch_count(&fbatch);
548
549		for (i = 0; i < nr; i++) {
550			struct folio *folio = fbatch.folios[i];
551
552			/* We rely upon deletion not changing folio->index */
553
554			if (xa_is_value(folio)) {
555				xa_has_values = true;
556				count++;
557				continue;
558			}
559
560			ret = mapping_evict_folio(mapping, folio);
561			folio_unlock(folio);
562			/*
563			 * Invalidation is a hint that the folio is no longer
564			 * of interest and try to speed up its reclaim.
565			 */
566			if (!ret) {
567				deactivate_file_folio(folio);
568				/* Likely in the lru cache of a remote CPU */
569				if (nr_failed)
570					(*nr_failed)++;
571			}
572			count += ret;
573		}
574
575		if (xa_has_values)
576			clear_shadow_entries(mapping, indices[0], indices[nr-1]);
577
578		folio_batch_remove_exceptionals(&fbatch);
579		folio_batch_release(&fbatch);
580		cond_resched();
581	}
582	return count;
583}
584
585/**
586 * invalidate_mapping_pages - Invalidate all clean, unlocked cache of one inode
587 * @mapping: the address_space which holds the cache to invalidate
588 * @start: the offset 'from' which to invalidate
589 * @end: the offset 'to' which to invalidate (inclusive)
590 *
591 * This function removes pages that are clean, unmapped and unlocked,
592 * as well as shadow entries. It will not block on IO activity.
593 *
594 * If you want to remove all the pages of one inode, regardless of
595 * their use and writeback state, use truncate_inode_pages().
596 *
597 * Return: The number of indices that had their contents invalidated
598 */
599unsigned long invalidate_mapping_pages(struct address_space *mapping,
600		pgoff_t start, pgoff_t end)
601{
602	return mapping_try_invalidate(mapping, start, end, NULL);
603}
604EXPORT_SYMBOL(invalidate_mapping_pages);
605
606static int folio_launder(struct address_space *mapping, struct folio *folio)
607{
608	if (!folio_test_dirty(folio))
609		return 0;
610	if (folio->mapping != mapping || mapping->a_ops->launder_folio == NULL)
611		return 0;
612	return mapping->a_ops->launder_folio(folio);
613}
614
615/*
616 * This is like mapping_evict_folio(), except it ignores the folio's
617 * refcount.  We do this because invalidate_inode_pages2() needs stronger
618 * invalidation guarantees, and cannot afford to leave folios behind because
619 * shrink_folio_list() has a temp ref on them, or because they're transiently
620 * sitting in the folio_add_lru() caches.
621 */
622int folio_unmap_invalidate(struct address_space *mapping, struct folio *folio,
623			   gfp_t gfp)
624{
625	void (*free_folio)(struct folio *);
626	int ret;
627
628	VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
629
630	if (folio_mapped(folio))
631		unmap_mapping_folio(folio);
632	BUG_ON(folio_mapped(folio));
633
634	ret = folio_launder(mapping, folio);
635	if (ret)
636		return ret;
637	if (folio->mapping != mapping)
638		return -EBUSY;
639	if (!filemap_release_folio(folio, gfp))
640		return -EBUSY;
641
642	spin_lock(&mapping->host->i_lock);
643	xa_lock_irq(&mapping->i_pages);
644	if (folio_test_dirty(folio))
645		goto failed;
646
647	BUG_ON(folio_has_private(folio));
648	__filemap_remove_folio(folio, NULL);
649	xa_unlock_irq(&mapping->i_pages);
650	if (mapping_shrinkable(mapping))
651		inode_lru_list_add(mapping->host);
652	free_folio = mapping->a_ops->free_folio;
653	spin_unlock(&mapping->host->i_lock);
654
655	if (free_folio)
656		free_folio(folio);
657	folio_put_refs(folio, folio_nr_pages(folio));
658	return 1;
659failed:
660	xa_unlock_irq(&mapping->i_pages);
661	spin_unlock(&mapping->host->i_lock);
662	return -EBUSY;
663}
664
665/**
666 * invalidate_inode_pages2_range - remove range of pages from an address_space
667 * @mapping: the address_space
668 * @start: the page offset 'from' which to invalidate
669 * @end: the page offset 'to' which to invalidate (inclusive)
670 *
671 * Any pages which are found to be mapped into pagetables are unmapped prior to
672 * invalidation.
673 *
674 * Return: -EBUSY if any pages could not be invalidated.
675 */
676int invalidate_inode_pages2_range(struct address_space *mapping,
677				  pgoff_t start, pgoff_t end)
678{
679	pgoff_t indices[PAGEVEC_SIZE];
680	struct folio_batch fbatch;
681	pgoff_t index;
682	int i;
683	int ret = 0;
684	int ret2 = 0;
685	int did_range_unmap = 0;
686
687	if (mapping_empty(mapping))
688		return 0;
689
690	folio_batch_init(&fbatch);
691	index = start;
692	while (find_get_entries(mapping, &index, end, &fbatch, indices)) {
693		bool xa_has_values = false;
694		int nr = folio_batch_count(&fbatch);
695
696		for (i = 0; i < nr; i++) {
697			struct folio *folio = fbatch.folios[i];
698
699			/* We rely upon deletion not changing folio->index */
700
701			if (xa_is_value(folio)) {
702				xa_has_values = true;
703				if (dax_mapping(mapping) &&
704				    !dax_invalidate_mapping_entry_sync(mapping, indices[i]))
705					ret = -EBUSY;
706				continue;
707			}
708
709			if (!did_range_unmap && folio_mapped(folio)) {
710				/*
711				 * If folio is mapped, before taking its lock,
712				 * zap the rest of the file in one hit.
713				 */
714				unmap_mapping_pages(mapping, indices[i],
715						(1 + end - indices[i]), false);
716				did_range_unmap = 1;
717			}
718
719			folio_lock(folio);
720			if (unlikely(folio->mapping != mapping)) {
721				folio_unlock(folio);
722				continue;
723			}
724			VM_BUG_ON_FOLIO(!folio_contains(folio, indices[i]), folio);
725			folio_wait_writeback(folio);
726			ret2 = folio_unmap_invalidate(mapping, folio, GFP_KERNEL);
727			if (ret2 < 0)
728				ret = ret2;
729			folio_unlock(folio);
730		}
731
732		if (xa_has_values)
733			clear_shadow_entries(mapping, indices[0], indices[nr-1]);
734
735		folio_batch_remove_exceptionals(&fbatch);
736		folio_batch_release(&fbatch);
737		cond_resched();
738	}
739	/*
740	 * For DAX we invalidate page tables after invalidating page cache.  We
741	 * could invalidate page tables while invalidating each entry however
742	 * that would be expensive. And doing range unmapping before doesn't
743	 * work as we have no cheap way to find whether page cache entry didn't
744	 * get remapped later.
745	 */
746	if (dax_mapping(mapping)) {
747		unmap_mapping_pages(mapping, start, end - start + 1, false);
748	}
749	return ret;
750}
751EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
752
753/**
754 * invalidate_inode_pages2 - remove all pages from an address_space
755 * @mapping: the address_space
756 *
757 * Any pages which are found to be mapped into pagetables are unmapped prior to
758 * invalidation.
759 *
760 * Return: -EBUSY if any pages could not be invalidated.
761 */
762int invalidate_inode_pages2(struct address_space *mapping)
763{
764	return invalidate_inode_pages2_range(mapping, 0, -1);
765}
766EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
767
768/**
769 * truncate_pagecache - unmap and remove pagecache that has been truncated
770 * @inode: inode
771 * @newsize: new file size
772 *
773 * inode's new i_size must already be written before truncate_pagecache
774 * is called.
775 *
776 * This function should typically be called before the filesystem
777 * releases resources associated with the freed range (eg. deallocates
778 * blocks). This way, pagecache will always stay logically coherent
779 * with on-disk format, and the filesystem would not have to deal with
780 * situations such as writepage being called for a page that has already
781 * had its underlying blocks deallocated.
782 */
783void truncate_pagecache(struct inode *inode, loff_t newsize)
784{
785	struct address_space *mapping = inode->i_mapping;
786	loff_t holebegin = round_up(newsize, PAGE_SIZE);
787
788	/*
789	 * unmap_mapping_range is called twice, first simply for
790	 * efficiency so that truncate_inode_pages does fewer
791	 * single-page unmaps.  However after this first call, and
792	 * before truncate_inode_pages finishes, it is possible for
793	 * private pages to be COWed, which remain after
794	 * truncate_inode_pages finishes, hence the second
795	 * unmap_mapping_range call must be made for correctness.
796	 */
797	unmap_mapping_range(mapping, holebegin, 0, 1);
798	truncate_inode_pages(mapping, newsize);
799	unmap_mapping_range(mapping, holebegin, 0, 1);
800}
801EXPORT_SYMBOL(truncate_pagecache);
802
803/**
804 * truncate_setsize - update inode and pagecache for a new file size
805 * @inode: inode
806 * @newsize: new file size
807 *
808 * truncate_setsize updates i_size and performs pagecache truncation (if
809 * necessary) to @newsize. It will be typically be called from the filesystem's
810 * setattr function when ATTR_SIZE is passed in.
811 *
812 * Must be called with a lock serializing truncates and writes (generally
813 * i_rwsem but e.g. xfs uses a different lock) and before all filesystem
814 * specific block truncation has been performed.
815 */
816void truncate_setsize(struct inode *inode, loff_t newsize)
817{
818	loff_t oldsize = inode->i_size;
819
820	i_size_write(inode, newsize);
821	if (newsize > oldsize)
822		pagecache_isize_extended(inode, oldsize, newsize);
823	truncate_pagecache(inode, newsize);
824}
825EXPORT_SYMBOL(truncate_setsize);
826
827/**
828 * pagecache_isize_extended - update pagecache after extension of i_size
829 * @inode:	inode for which i_size was extended
830 * @from:	original inode size
831 * @to:		new inode size
832 *
833 * Handle extension of inode size either caused by extending truncate or
834 * by write starting after current i_size.  We mark the page straddling
835 * current i_size RO so that page_mkwrite() is called on the first
836 * write access to the page.  The filesystem will update its per-block
837 * information before user writes to the page via mmap after the i_size
838 * has been changed.
839 *
840 * The function must be called after i_size is updated so that page fault
841 * coming after we unlock the folio will already see the new i_size.
842 * The function must be called while we still hold i_rwsem - this not only
843 * makes sure i_size is stable but also that userspace cannot observe new
844 * i_size value before we are prepared to store mmap writes at new inode size.
845 */
846void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to)
847{
848	int bsize = i_blocksize(inode);
849	loff_t rounded_from;
850	struct folio *folio;
851
852	WARN_ON(to > inode->i_size);
853
854	if (from >= to || bsize >= PAGE_SIZE)
855		return;
856	/* Page straddling @from will not have any hole block created? */
857	rounded_from = round_up(from, bsize);
858	if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1)))
859		return;
860
861	folio = filemap_lock_folio(inode->i_mapping, from / PAGE_SIZE);
862	/* Folio not cached? Nothing to do */
863	if (IS_ERR(folio))
864		return;
865	/*
866	 * See folio_clear_dirty_for_io() for details why folio_mark_dirty()
867	 * is needed.
868	 */
869	if (folio_mkclean(folio))
870		folio_mark_dirty(folio);
871
872	/*
873	 * The post-eof range of the folio must be zeroed before it is exposed
874	 * to the file. Writeback normally does this, but since i_size has been
875	 * increased we handle it here.
876	 */
877	if (folio_test_dirty(folio)) {
878		unsigned int offset, end;
879
880		offset = from - folio_pos(folio);
881		end = min_t(unsigned int, to - folio_pos(folio),
882			    folio_size(folio));
883		folio_zero_segment(folio, offset, end);
884	}
885
886	folio_unlock(folio);
887	folio_put(folio);
888}
889EXPORT_SYMBOL(pagecache_isize_extended);
890
891/**
892 * truncate_pagecache_range - unmap and remove pagecache that is hole-punched
893 * @inode: inode
894 * @lstart: offset of beginning of hole
895 * @lend: offset of last byte of hole
896 *
897 * This function should typically be called before the filesystem
898 * releases resources associated with the freed range (eg. deallocates
899 * blocks). This way, pagecache will always stay logically coherent
900 * with on-disk format, and the filesystem would not have to deal with
901 * situations such as writepage being called for a page that has already
902 * had its underlying blocks deallocated.
903 */
904void truncate_pagecache_range(struct inode *inode, loff_t lstart, loff_t lend)
905{
906	struct address_space *mapping = inode->i_mapping;
907	loff_t unmap_start = round_up(lstart, PAGE_SIZE);
908	loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1;
909	/*
910	 * This rounding is currently just for example: unmap_mapping_range
911	 * expands its hole outwards, whereas we want it to contract the hole
912	 * inwards.  However, existing callers of truncate_pagecache_range are
913	 * doing their own page rounding first.  Note that unmap_mapping_range
914	 * allows holelen 0 for all, and we allow lend -1 for end of file.
915	 */
916
917	/*
918	 * Unlike in truncate_pagecache, unmap_mapping_range is called only
919	 * once (before truncating pagecache), and without "even_cows" flag:
920	 * hole-punching should not remove private COWed pages from the hole.
921	 */
922	if ((u64)unmap_end > (u64)unmap_start)
923		unmap_mapping_range(mapping, unmap_start,
924				    1 + unmap_end - unmap_start, 0);
925	truncate_inode_pages_range(mapping, lstart, lend);
926}
927EXPORT_SYMBOL(truncate_pagecache_range);