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/buffer_head.h>	/* grr. try_to_release_page,
 23				   do_invalidatepage */
 24#include <linux/shmem_fs.h>
 25#include <linux/cleancache.h>
 26#include <linux/rmap.h>
 27#include "internal.h"
 28
 29/*
 30 * Regular page slots are stabilized by the page lock even without the tree
 31 * itself locked.  These unlocked entries need verification under the tree
 32 * lock.
 33 */
 34static inline void __clear_shadow_entry(struct address_space *mapping,
 35				pgoff_t index, void *entry)
 36{
 37	XA_STATE(xas, &mapping->i_pages, index);
 38
 39	xas_set_update(&xas, workingset_update_node);
 40	if (xas_load(&xas) != entry)
 41		return;
 42	xas_store(&xas, NULL);
 43	mapping->nrexceptional--;
 44}
 45
 46static void clear_shadow_entry(struct address_space *mapping, pgoff_t index,
 47			       void *entry)
 48{
 49	xa_lock_irq(&mapping->i_pages);
 50	__clear_shadow_entry(mapping, index, entry);
 51	xa_unlock_irq(&mapping->i_pages);
 52}
 53
 54/*
 55 * Unconditionally remove exceptional entries. Usually called from truncate
 56 * path. Note that the pagevec may be altered by this function by removing
 57 * exceptional entries similar to what pagevec_remove_exceptionals does.
 58 */
 59static void truncate_exceptional_pvec_entries(struct address_space *mapping,
 60				struct pagevec *pvec, pgoff_t *indices,
 61				pgoff_t end)
 62{
 63	int i, j;
 64	bool dax, lock;
 65
 66	/* Handled by shmem itself */
 67	if (shmem_mapping(mapping))
 68		return;
 69
 70	for (j = 0; j < pagevec_count(pvec); j++)
 71		if (xa_is_value(pvec->pages[j]))
 72			break;
 73
 74	if (j == pagevec_count(pvec))
 75		return;
 76
 77	dax = dax_mapping(mapping);
 78	lock = !dax && indices[j] < end;
 79	if (lock)
 80		xa_lock_irq(&mapping->i_pages);
 81
 82	for (i = j; i < pagevec_count(pvec); i++) {
 83		struct page *page = pvec->pages[i];
 84		pgoff_t index = indices[i];
 85
 86		if (!xa_is_value(page)) {
 87			pvec->pages[j++] = page;
 88			continue;
 89		}
 90
 91		if (index >= end)
 92			continue;
 93
 94		if (unlikely(dax)) {
 95			dax_delete_mapping_entry(mapping, index);
 96			continue;
 97		}
 98
 99		__clear_shadow_entry(mapping, index, page);
100	}
101
102	if (lock)
103		xa_unlock_irq(&mapping->i_pages);
104	pvec->nr = j;
105}
106
107/*
108 * Invalidate exceptional entry if easily possible. This handles exceptional
109 * entries for invalidate_inode_pages().
110 */
111static int invalidate_exceptional_entry(struct address_space *mapping,
112					pgoff_t index, void *entry)
113{
114	/* Handled by shmem itself, or for DAX we do nothing. */
115	if (shmem_mapping(mapping) || dax_mapping(mapping))
116		return 1;
117	clear_shadow_entry(mapping, index, entry);
118	return 1;
119}
120
121/*
122 * Invalidate exceptional entry if clean. This handles exceptional entries for
123 * invalidate_inode_pages2() so for DAX it evicts only clean entries.
124 */
125static int invalidate_exceptional_entry2(struct address_space *mapping,
126					 pgoff_t index, void *entry)
127{
128	/* Handled by shmem itself */
129	if (shmem_mapping(mapping))
130		return 1;
131	if (dax_mapping(mapping))
132		return dax_invalidate_mapping_entry_sync(mapping, index);
133	clear_shadow_entry(mapping, index, entry);
134	return 1;
135}
136
137/**
138 * do_invalidatepage - invalidate part or all of a page
139 * @page: the page which is affected
140 * @offset: start of the range to invalidate
141 * @length: length of the range to invalidate
142 *
143 * do_invalidatepage() is called when all or part of the page has become
144 * invalidated by a truncate operation.
145 *
146 * do_invalidatepage() does not have to release all buffers, but it must
147 * ensure that no dirty buffer is left outside @offset and that no I/O
148 * is underway against any of the blocks which are outside the truncation
149 * point.  Because the caller is about to free (and possibly reuse) those
150 * blocks on-disk.
151 */
152void do_invalidatepage(struct page *page, unsigned int offset,
153		       unsigned int length)
154{
155	void (*invalidatepage)(struct page *, unsigned int, unsigned int);
156
157	invalidatepage = page->mapping->a_ops->invalidatepage;
158#ifdef CONFIG_BLOCK
159	if (!invalidatepage)
160		invalidatepage = block_invalidatepage;
161#endif
162	if (invalidatepage)
163		(*invalidatepage)(page, offset, length);
164}
165
166/*
167 * If truncate cannot remove the fs-private metadata from the page, the page
168 * becomes orphaned.  It will be left on the LRU and may even be mapped into
169 * user pagetables if we're racing with filemap_fault().
170 *
171 * We need to bale out if page->mapping is no longer equal to the original
172 * mapping.  This happens a) when the VM reclaimed the page while we waited on
173 * its lock, b) when a concurrent invalidate_mapping_pages got there first and
174 * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
175 */
176static void
177truncate_cleanup_page(struct address_space *mapping, struct page *page)
178{
179	if (page_mapped(page)) {
180		pgoff_t nr = PageTransHuge(page) ? HPAGE_PMD_NR : 1;
181		unmap_mapping_pages(mapping, page->index, nr, false);
182	}
183
184	if (page_has_private(page))
185		do_invalidatepage(page, 0, PAGE_SIZE);
186
187	/*
188	 * Some filesystems seem to re-dirty the page even after
189	 * the VM has canceled the dirty bit (eg ext3 journaling).
190	 * Hence dirty accounting check is placed after invalidation.
191	 */
192	cancel_dirty_page(page);
193	ClearPageMappedToDisk(page);
194}
195
196/*
197 * This is for invalidate_mapping_pages().  That function can be called at
198 * any time, and is not supposed to throw away dirty pages.  But pages can
199 * be marked dirty at any time too, so use remove_mapping which safely
200 * discards clean, unused pages.
201 *
202 * Returns non-zero if the page was successfully invalidated.
203 */
204static int
205invalidate_complete_page(struct address_space *mapping, struct page *page)
206{
207	int ret;
208
209	if (page->mapping != mapping)
210		return 0;
211
212	if (page_has_private(page) && !try_to_release_page(page, 0))
213		return 0;
214
215	ret = remove_mapping(mapping, page);
216
217	return ret;
218}
219
220int truncate_inode_page(struct address_space *mapping, struct page *page)
221{
222	VM_BUG_ON_PAGE(PageTail(page), page);
223
224	if (page->mapping != mapping)
225		return -EIO;
226
227	truncate_cleanup_page(mapping, page);
228	delete_from_page_cache(page);
229	return 0;
230}
231
232/*
233 * Used to get rid of pages on hardware memory corruption.
234 */
235int generic_error_remove_page(struct address_space *mapping, struct page *page)
236{
237	if (!mapping)
238		return -EINVAL;
239	/*
240	 * Only punch for normal data pages for now.
241	 * Handling other types like directories would need more auditing.
242	 */
243	if (!S_ISREG(mapping->host->i_mode))
244		return -EIO;
245	return truncate_inode_page(mapping, page);
246}
247EXPORT_SYMBOL(generic_error_remove_page);
248
249/*
250 * Safely invalidate one page from its pagecache mapping.
251 * It only drops clean, unused pages. The page must be locked.
252 *
253 * Returns 1 if the page is successfully invalidated, otherwise 0.
254 */
255int invalidate_inode_page(struct page *page)
256{
257	struct address_space *mapping = page_mapping(page);
258	if (!mapping)
259		return 0;
260	if (PageDirty(page) || PageWriteback(page))
261		return 0;
262	if (page_mapped(page))
263		return 0;
264	return invalidate_complete_page(mapping, page);
265}
266
267/**
268 * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets
269 * @mapping: mapping to truncate
270 * @lstart: offset from which to truncate
271 * @lend: offset to which to truncate (inclusive)
272 *
273 * Truncate the page cache, removing the pages that are between
274 * specified offsets (and zeroing out partial pages
275 * if lstart or lend + 1 is not page aligned).
276 *
277 * Truncate takes two passes - the first pass is nonblocking.  It will not
278 * block on page locks and it will not block on writeback.  The second pass
279 * will wait.  This is to prevent as much IO as possible in the affected region.
280 * The first pass will remove most pages, so the search cost of the second pass
281 * is low.
282 *
283 * We pass down the cache-hot hint to the page freeing code.  Even if the
284 * mapping is large, it is probably the case that the final pages are the most
285 * recently touched, and freeing happens in ascending file offset order.
286 *
287 * Note that since ->invalidatepage() accepts range to invalidate
288 * truncate_inode_pages_range is able to handle cases where lend + 1 is not
289 * page aligned properly.
290 */
291void truncate_inode_pages_range(struct address_space *mapping,
292				loff_t lstart, loff_t lend)
293{
294	pgoff_t		start;		/* inclusive */
295	pgoff_t		end;		/* exclusive */
296	unsigned int	partial_start;	/* inclusive */
297	unsigned int	partial_end;	/* exclusive */
298	struct pagevec	pvec;
299	pgoff_t		indices[PAGEVEC_SIZE];
300	pgoff_t		index;
301	int		i;
302
303	if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
304		goto out;
305
306	/* Offsets within partial pages */
307	partial_start = lstart & (PAGE_SIZE - 1);
308	partial_end = (lend + 1) & (PAGE_SIZE - 1);
309
310	/*
311	 * 'start' and 'end' always covers the range of pages to be fully
312	 * truncated. Partial pages are covered with 'partial_start' at the
313	 * start of the range and 'partial_end' at the end of the range.
314	 * Note that 'end' is exclusive while 'lend' is inclusive.
315	 */
316	start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
317	if (lend == -1)
318		/*
319		 * lend == -1 indicates end-of-file so we have to set 'end'
320		 * to the highest possible pgoff_t and since the type is
321		 * unsigned we're using -1.
322		 */
323		end = -1;
324	else
325		end = (lend + 1) >> PAGE_SHIFT;
326
327	pagevec_init(&pvec);
328	index = start;
329	while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
330			min(end - index, (pgoff_t)PAGEVEC_SIZE),
331			indices)) {
332		/*
333		 * Pagevec array has exceptional entries and we may also fail
334		 * to lock some pages. So we store pages that can be deleted
335		 * in a new pagevec.
336		 */
337		struct pagevec locked_pvec;
338
339		pagevec_init(&locked_pvec);
340		for (i = 0; i < pagevec_count(&pvec); i++) {
341			struct page *page = pvec.pages[i];
342
343			/* We rely upon deletion not changing page->index */
344			index = indices[i];
345			if (index >= end)
346				break;
347
348			if (xa_is_value(page))
349				continue;
350
351			if (!trylock_page(page))
352				continue;
353			WARN_ON(page_to_index(page) != index);
354			if (PageWriteback(page)) {
355				unlock_page(page);
356				continue;
357			}
358			if (page->mapping != mapping) {
359				unlock_page(page);
360				continue;
361			}
362			pagevec_add(&locked_pvec, page);
363		}
364		for (i = 0; i < pagevec_count(&locked_pvec); i++)
365			truncate_cleanup_page(mapping, locked_pvec.pages[i]);
366		delete_from_page_cache_batch(mapping, &locked_pvec);
367		for (i = 0; i < pagevec_count(&locked_pvec); i++)
368			unlock_page(locked_pvec.pages[i]);
369		truncate_exceptional_pvec_entries(mapping, &pvec, indices, end);
370		pagevec_release(&pvec);
371		cond_resched();
372		index++;
373	}
 
374	if (partial_start) {
375		struct page *page = find_lock_page(mapping, start - 1);
376		if (page) {
377			unsigned int top = PAGE_SIZE;
378			if (start > end) {
379				/* Truncation within a single page */
380				top = partial_end;
381				partial_end = 0;
382			}
383			wait_on_page_writeback(page);
384			zero_user_segment(page, partial_start, top);
385			cleancache_invalidate_page(mapping, page);
386			if (page_has_private(page))
387				do_invalidatepage(page, partial_start,
388						  top - partial_start);
389			unlock_page(page);
390			put_page(page);
391		}
392	}
393	if (partial_end) {
394		struct page *page = find_lock_page(mapping, end);
395		if (page) {
396			wait_on_page_writeback(page);
397			zero_user_segment(page, 0, partial_end);
398			cleancache_invalidate_page(mapping, page);
399			if (page_has_private(page))
400				do_invalidatepage(page, 0,
401						  partial_end);
402			unlock_page(page);
403			put_page(page);
404		}
405	}
406	/*
407	 * If the truncation happened within a single page no pages
408	 * will be released, just zeroed, so we can bail out now.
409	 */
410	if (start >= end)
411		goto out;
412
413	index = start;
414	for ( ; ; ) {
415		cond_resched();
416		if (!pagevec_lookup_entries(&pvec, mapping, index,
417			min(end - index, (pgoff_t)PAGEVEC_SIZE), indices)) {
418			/* If all gone from start onwards, we're done */
419			if (index == start)
420				break;
421			/* Otherwise restart to make sure all gone */
422			index = start;
423			continue;
424		}
425		if (index == start && indices[0] >= end) {
426			/* All gone out of hole to be punched, we're done */
427			pagevec_remove_exceptionals(&pvec);
428			pagevec_release(&pvec);
429			break;
430		}
431
432		for (i = 0; i < pagevec_count(&pvec); i++) {
433			struct page *page = pvec.pages[i];
434
435			/* We rely upon deletion not changing page->index */
436			index = indices[i];
437			if (index >= end) {
438				/* Restart punch to make sure all gone */
439				index = start - 1;
440				break;
441			}
442
443			if (xa_is_value(page))
444				continue;
445
446			lock_page(page);
447			WARN_ON(page_to_index(page) != index);
448			wait_on_page_writeback(page);
449			truncate_inode_page(mapping, page);
450			unlock_page(page);
451		}
452		truncate_exceptional_pvec_entries(mapping, &pvec, indices, end);
453		pagevec_release(&pvec);
454		index++;
455	}
456
457out:
458	cleancache_invalidate_inode(mapping);
459}
460EXPORT_SYMBOL(truncate_inode_pages_range);
461
462/**
463 * truncate_inode_pages - truncate *all* the pages from an offset
464 * @mapping: mapping to truncate
465 * @lstart: offset from which to truncate
466 *
467 * Called under (and serialised by) inode->i_mutex.
468 *
469 * Note: When this function returns, there can be a page in the process of
470 * deletion (inside __delete_from_page_cache()) in the specified range.  Thus
471 * mapping->nrpages can be non-zero when this function returns even after
472 * truncation of the whole mapping.
473 */
474void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
475{
476	truncate_inode_pages_range(mapping, lstart, (loff_t)-1);
477}
478EXPORT_SYMBOL(truncate_inode_pages);
479
480/**
481 * truncate_inode_pages_final - truncate *all* pages before inode dies
482 * @mapping: mapping to truncate
483 *
484 * Called under (and serialized by) inode->i_mutex.
485 *
486 * Filesystems have to use this in the .evict_inode path to inform the
487 * VM that this is the final truncate and the inode is going away.
488 */
489void truncate_inode_pages_final(struct address_space *mapping)
490{
491	unsigned long nrexceptional;
492	unsigned long nrpages;
493
494	/*
495	 * Page reclaim can not participate in regular inode lifetime
496	 * management (can't call iput()) and thus can race with the
497	 * inode teardown.  Tell it when the address space is exiting,
498	 * so that it does not install eviction information after the
499	 * final truncate has begun.
500	 */
501	mapping_set_exiting(mapping);
502
503	/*
504	 * When reclaim installs eviction entries, it increases
505	 * nrexceptional first, then decreases nrpages.  Make sure we see
506	 * this in the right order or we might miss an entry.
507	 */
508	nrpages = mapping->nrpages;
509	smp_rmb();
510	nrexceptional = mapping->nrexceptional;
511
512	if (nrpages || nrexceptional) {
513		/*
514		 * As truncation uses a lockless tree lookup, cycle
515		 * the tree lock to make sure any ongoing tree
516		 * modification that does not see AS_EXITING is
517		 * completed before starting the final truncate.
518		 */
519		xa_lock_irq(&mapping->i_pages);
520		xa_unlock_irq(&mapping->i_pages);
521	}
522
523	/*
524	 * Cleancache needs notification even if there are no pages or shadow
525	 * entries.
526	 */
527	truncate_inode_pages(mapping, 0);
528}
529EXPORT_SYMBOL(truncate_inode_pages_final);
530
531/**
532 * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
533 * @mapping: the address_space which holds the pages to invalidate
534 * @start: the offset 'from' which to invalidate
535 * @end: the offset 'to' which to invalidate (inclusive)
536 *
537 * This function only removes the unlocked pages, if you want to
538 * remove all the pages of one inode, you must call truncate_inode_pages.
539 *
540 * invalidate_mapping_pages() will not block on IO activity. It will not
541 * invalidate pages which are dirty, locked, under writeback or mapped into
542 * pagetables.
543 *
544 * Return: the number of the pages that were invalidated
545 */
546unsigned long invalidate_mapping_pages(struct address_space *mapping,
547		pgoff_t start, pgoff_t end)
548{
549	pgoff_t indices[PAGEVEC_SIZE];
550	struct pagevec pvec;
551	pgoff_t index = start;
552	unsigned long ret;
553	unsigned long count = 0;
554	int i;
555
556	pagevec_init(&pvec);
557	while (index <= end && pagevec_lookup_entries(&pvec, mapping, index,
558			min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1,
559			indices)) {
560		for (i = 0; i < pagevec_count(&pvec); i++) {
561			struct page *page = pvec.pages[i];
562
563			/* We rely upon deletion not changing page->index */
564			index = indices[i];
565			if (index > end)
566				break;
567
568			if (xa_is_value(page)) {
569				invalidate_exceptional_entry(mapping, index,
570							     page);
571				continue;
572			}
573
574			if (!trylock_page(page))
575				continue;
576
577			WARN_ON(page_to_index(page) != index);
578
579			/* Middle of THP: skip */
580			if (PageTransTail(page)) {
581				unlock_page(page);
582				continue;
583			} else if (PageTransHuge(page)) {
584				index += HPAGE_PMD_NR - 1;
585				i += HPAGE_PMD_NR - 1;
586				/*
587				 * 'end' is in the middle of THP. Don't
588				 * invalidate the page as the part outside of
589				 * 'end' could be still useful.
590				 */
591				if (index > end) {
592					unlock_page(page);
593					continue;
594				}
595
596				/* Take a pin outside pagevec */
597				get_page(page);
598
599				/*
600				 * Drop extra pins before trying to invalidate
601				 * the huge page.
602				 */
603				pagevec_remove_exceptionals(&pvec);
604				pagevec_release(&pvec);
605			}
606
607			ret = invalidate_inode_page(page);
608			unlock_page(page);
609			/*
610			 * Invalidation is a hint that the page is no longer
611			 * of interest and try to speed up its reclaim.
612			 */
613			if (!ret)
614				deactivate_file_page(page);
615			if (PageTransHuge(page))
616				put_page(page);
 
 
617			count += ret;
618		}
619		pagevec_remove_exceptionals(&pvec);
620		pagevec_release(&pvec);
621		cond_resched();
622		index++;
623	}
624	return count;
625}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
626EXPORT_SYMBOL(invalidate_mapping_pages);
627
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
628/*
629 * This is like invalidate_complete_page(), except it ignores the page's
630 * refcount.  We do this because invalidate_inode_pages2() needs stronger
631 * invalidation guarantees, and cannot afford to leave pages behind because
632 * shrink_page_list() has a temp ref on them, or because they're transiently
633 * sitting in the lru_cache_add() pagevecs.
634 */
635static int
636invalidate_complete_page2(struct address_space *mapping, struct page *page)
637{
638	unsigned long flags;
639
640	if (page->mapping != mapping)
641		return 0;
642
643	if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
644		return 0;
645
646	xa_lock_irqsave(&mapping->i_pages, flags);
647	if (PageDirty(page))
648		goto failed;
649
650	BUG_ON(page_has_private(page));
651	__delete_from_page_cache(page, NULL);
652	xa_unlock_irqrestore(&mapping->i_pages, flags);
653
654	if (mapping->a_ops->freepage)
655		mapping->a_ops->freepage(page);
656
657	put_page(page);	/* pagecache ref */
658	return 1;
659failed:
660	xa_unlock_irqrestore(&mapping->i_pages, flags);
661	return 0;
662}
663
664static int do_launder_page(struct address_space *mapping, struct page *page)
665{
666	if (!PageDirty(page))
667		return 0;
668	if (page->mapping != mapping || mapping->a_ops->launder_page == NULL)
669		return 0;
670	return mapping->a_ops->launder_page(page);
671}
672
673/**
674 * invalidate_inode_pages2_range - remove range of pages from an address_space
675 * @mapping: the address_space
676 * @start: the page offset 'from' which to invalidate
677 * @end: the page offset 'to' which to invalidate (inclusive)
678 *
679 * Any pages which are found to be mapped into pagetables are unmapped prior to
680 * invalidation.
681 *
682 * Return: -EBUSY if any pages could not be invalidated.
683 */
684int invalidate_inode_pages2_range(struct address_space *mapping,
685				  pgoff_t start, pgoff_t end)
686{
687	pgoff_t indices[PAGEVEC_SIZE];
688	struct pagevec pvec;
689	pgoff_t index;
690	int i;
691	int ret = 0;
692	int ret2 = 0;
693	int did_range_unmap = 0;
694
695	if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
696		goto out;
697
698	pagevec_init(&pvec);
699	index = start;
700	while (index <= end && pagevec_lookup_entries(&pvec, mapping, index,
701			min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1,
702			indices)) {
703		for (i = 0; i < pagevec_count(&pvec); i++) {
704			struct page *page = pvec.pages[i];
705
706			/* We rely upon deletion not changing page->index */
707			index = indices[i];
708			if (index > end)
709				break;
710
711			if (xa_is_value(page)) {
712				if (!invalidate_exceptional_entry2(mapping,
713								   index, page))
714					ret = -EBUSY;
715				continue;
716			}
717
 
 
 
 
 
 
 
 
 
 
718			lock_page(page);
719			WARN_ON(page_to_index(page) != index);
720			if (page->mapping != mapping) {
721				unlock_page(page);
722				continue;
723			}
724			wait_on_page_writeback(page);
725			if (page_mapped(page)) {
726				if (!did_range_unmap) {
727					/*
728					 * Zap the rest of the file in one hit.
729					 */
730					unmap_mapping_pages(mapping, index,
731						(1 + end - index), false);
732					did_range_unmap = 1;
733				} else {
734					/*
735					 * Just zap this page
736					 */
737					unmap_mapping_pages(mapping, index,
738								1, false);
739				}
740			}
741			BUG_ON(page_mapped(page));
 
742			ret2 = do_launder_page(mapping, page);
743			if (ret2 == 0) {
744				if (!invalidate_complete_page2(mapping, page))
745					ret2 = -EBUSY;
746			}
747			if (ret2 < 0)
748				ret = ret2;
749			unlock_page(page);
750		}
751		pagevec_remove_exceptionals(&pvec);
752		pagevec_release(&pvec);
753		cond_resched();
754		index++;
755	}
756	/*
757	 * For DAX we invalidate page tables after invalidating page cache.  We
758	 * could invalidate page tables while invalidating each entry however
759	 * that would be expensive. And doing range unmapping before doesn't
760	 * work as we have no cheap way to find whether page cache entry didn't
761	 * get remapped later.
762	 */
763	if (dax_mapping(mapping)) {
764		unmap_mapping_pages(mapping, start, end - start + 1, false);
765	}
766out:
767	cleancache_invalidate_inode(mapping);
768	return ret;
769}
770EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
771
772/**
773 * invalidate_inode_pages2 - remove all pages from an address_space
774 * @mapping: the address_space
775 *
776 * Any pages which are found to be mapped into pagetables are unmapped prior to
777 * invalidation.
778 *
779 * Return: -EBUSY if any pages could not be invalidated.
780 */
781int invalidate_inode_pages2(struct address_space *mapping)
782{
783	return invalidate_inode_pages2_range(mapping, 0, -1);
784}
785EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
786
787/**
788 * truncate_pagecache - unmap and remove pagecache that has been truncated
789 * @inode: inode
790 * @newsize: new file size
791 *
792 * inode's new i_size must already be written before truncate_pagecache
793 * is called.
794 *
795 * This function should typically be called before the filesystem
796 * releases resources associated with the freed range (eg. deallocates
797 * blocks). This way, pagecache will always stay logically coherent
798 * with on-disk format, and the filesystem would not have to deal with
799 * situations such as writepage being called for a page that has already
800 * had its underlying blocks deallocated.
801 */
802void truncate_pagecache(struct inode *inode, loff_t newsize)
803{
804	struct address_space *mapping = inode->i_mapping;
805	loff_t holebegin = round_up(newsize, PAGE_SIZE);
806
807	/*
808	 * unmap_mapping_range is called twice, first simply for
809	 * efficiency so that truncate_inode_pages does fewer
810	 * single-page unmaps.  However after this first call, and
811	 * before truncate_inode_pages finishes, it is possible for
812	 * private pages to be COWed, which remain after
813	 * truncate_inode_pages finishes, hence the second
814	 * unmap_mapping_range call must be made for correctness.
815	 */
816	unmap_mapping_range(mapping, holebegin, 0, 1);
817	truncate_inode_pages(mapping, newsize);
818	unmap_mapping_range(mapping, holebegin, 0, 1);
819}
820EXPORT_SYMBOL(truncate_pagecache);
821
822/**
823 * truncate_setsize - update inode and pagecache for a new file size
824 * @inode: inode
825 * @newsize: new file size
826 *
827 * truncate_setsize updates i_size and performs pagecache truncation (if
828 * necessary) to @newsize. It will be typically be called from the filesystem's
829 * setattr function when ATTR_SIZE is passed in.
830 *
831 * Must be called with a lock serializing truncates and writes (generally
832 * i_mutex but e.g. xfs uses a different lock) and before all filesystem
833 * specific block truncation has been performed.
834 */
835void truncate_setsize(struct inode *inode, loff_t newsize)
836{
837	loff_t oldsize = inode->i_size;
838
839	i_size_write(inode, newsize);
840	if (newsize > oldsize)
841		pagecache_isize_extended(inode, oldsize, newsize);
842	truncate_pagecache(inode, newsize);
843}
844EXPORT_SYMBOL(truncate_setsize);
845
846/**
847 * pagecache_isize_extended - update pagecache after extension of i_size
848 * @inode:	inode for which i_size was extended
849 * @from:	original inode size
850 * @to:		new inode size
851 *
852 * Handle extension of inode size either caused by extending truncate or by
853 * write starting after current i_size. We mark the page straddling current
854 * i_size RO so that page_mkwrite() is called on the nearest write access to
855 * the page.  This way filesystem can be sure that page_mkwrite() is called on
856 * the page before user writes to the page via mmap after the i_size has been
857 * changed.
858 *
859 * The function must be called after i_size is updated so that page fault
860 * coming after we unlock the page will already see the new i_size.
861 * The function must be called while we still hold i_mutex - this not only
862 * makes sure i_size is stable but also that userspace cannot observe new
863 * i_size value before we are prepared to store mmap writes at new inode size.
864 */
865void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to)
866{
867	int bsize = i_blocksize(inode);
868	loff_t rounded_from;
869	struct page *page;
870	pgoff_t index;
871
872	WARN_ON(to > inode->i_size);
873
874	if (from >= to || bsize == PAGE_SIZE)
875		return;
876	/* Page straddling @from will not have any hole block created? */
877	rounded_from = round_up(from, bsize);
878	if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1)))
879		return;
880
881	index = from >> PAGE_SHIFT;
882	page = find_lock_page(inode->i_mapping, index);
883	/* Page not cached? Nothing to do */
884	if (!page)
885		return;
886	/*
887	 * See clear_page_dirty_for_io() for details why set_page_dirty()
888	 * is needed.
889	 */
890	if (page_mkclean(page))
891		set_page_dirty(page);
892	unlock_page(page);
893	put_page(page);
894}
895EXPORT_SYMBOL(pagecache_isize_extended);
896
897/**
898 * truncate_pagecache_range - unmap and remove pagecache that is hole-punched
899 * @inode: inode
900 * @lstart: offset of beginning of hole
901 * @lend: offset of last byte of hole
902 *
903 * This function should typically be called before the filesystem
904 * releases resources associated with the freed range (eg. deallocates
905 * blocks). This way, pagecache will always stay logically coherent
906 * with on-disk format, and the filesystem would not have to deal with
907 * situations such as writepage being called for a page that has already
908 * had its underlying blocks deallocated.
909 */
910void truncate_pagecache_range(struct inode *inode, loff_t lstart, loff_t lend)
911{
912	struct address_space *mapping = inode->i_mapping;
913	loff_t unmap_start = round_up(lstart, PAGE_SIZE);
914	loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1;
915	/*
916	 * This rounding is currently just for example: unmap_mapping_range
917	 * expands its hole outwards, whereas we want it to contract the hole
918	 * inwards.  However, existing callers of truncate_pagecache_range are
919	 * doing their own page rounding first.  Note that unmap_mapping_range
920	 * allows holelen 0 for all, and we allow lend -1 for end of file.
921	 */
922
923	/*
924	 * Unlike in truncate_pagecache, unmap_mapping_range is called only
925	 * once (before truncating pagecache), and without "even_cows" flag:
926	 * hole-punching should not remove private COWed pages from the hole.
927	 */
928	if ((u64)unmap_end > (u64)unmap_start)
929		unmap_mapping_range(mapping, unmap_start,
930				    1 + unmap_end - unmap_start, 0);
931	truncate_inode_pages_range(mapping, lstart, lend);
932}
933EXPORT_SYMBOL(truncate_pagecache_range);