2 * mm/truncate.c - code for taking down pages from address_spaces
4 * Copyright (C) 2002, Linus Torvalds
6 * 10Sep2002 Andrew Morton
10 #include <linux/kernel.h>
11 #include <linux/backing-dev.h>
12 #include <linux/dax.h>
13 #include <linux/gfp.h>
15 #include <linux/swap.h>
16 #include <linux/export.h>
17 #include <linux/pagemap.h>
18 #include <linux/highmem.h>
19 #include <linux/pagevec.h>
20 #include <linux/task_io_accounting_ops.h>
21 #include <linux/buffer_head.h> /* grr. try_to_release_page,
23 #include <linux/cleancache.h>
24 #include <linux/rmap.h>
27 static void clear_shadow_entry(struct address_space
*mapping
, pgoff_t index
,
30 struct radix_tree_node
*node
;
33 spin_lock_irq(&mapping
->tree_lock
);
35 * Regular page slots are stabilized by the page lock even
36 * without the tree itself locked. These unlocked entries
37 * need verification under the tree lock.
39 if (!__radix_tree_lookup(&mapping
->page_tree
, index
, &node
, &slot
))
43 __radix_tree_replace(&mapping
->page_tree
, node
, slot
, NULL
,
44 workingset_update_node
, mapping
);
45 mapping
->nrexceptional
--;
47 spin_unlock_irq(&mapping
->tree_lock
);
51 * Unconditionally remove exceptional entry. Usually called from truncate path.
53 static void truncate_exceptional_entry(struct address_space
*mapping
,
54 pgoff_t index
, void *entry
)
56 /* Handled by shmem itself */
57 if (shmem_mapping(mapping
))
60 if (dax_mapping(mapping
)) {
61 dax_delete_mapping_entry(mapping
, index
);
64 clear_shadow_entry(mapping
, index
, entry
);
68 * Invalidate exceptional entry if easily possible. This handles exceptional
69 * entries for invalidate_inode_pages().
71 static int invalidate_exceptional_entry(struct address_space
*mapping
,
72 pgoff_t index
, void *entry
)
74 /* Handled by shmem itself, or for DAX we do nothing. */
75 if (shmem_mapping(mapping
) || dax_mapping(mapping
))
77 clear_shadow_entry(mapping
, index
, entry
);
82 * Invalidate exceptional entry if clean. This handles exceptional entries for
83 * invalidate_inode_pages2() so for DAX it evicts only clean entries.
85 static int invalidate_exceptional_entry2(struct address_space
*mapping
,
86 pgoff_t index
, void *entry
)
88 /* Handled by shmem itself */
89 if (shmem_mapping(mapping
))
91 if (dax_mapping(mapping
))
92 return dax_invalidate_mapping_entry_sync(mapping
, index
);
93 clear_shadow_entry(mapping
, index
, entry
);
98 * do_invalidatepage - invalidate part or all of a page
99 * @page: the page which is affected
100 * @offset: start of the range to invalidate
101 * @length: length of the range to invalidate
103 * do_invalidatepage() is called when all or part of the page has become
104 * invalidated by a truncate operation.
106 * do_invalidatepage() does not have to release all buffers, but it must
107 * ensure that no dirty buffer is left outside @offset and that no I/O
108 * is underway against any of the blocks which are outside the truncation
109 * point. Because the caller is about to free (and possibly reuse) those
112 void do_invalidatepage(struct page
*page
, unsigned int offset
,
115 void (*invalidatepage
)(struct page
*, unsigned int, unsigned int);
117 invalidatepage
= page
->mapping
->a_ops
->invalidatepage
;
120 invalidatepage
= block_invalidatepage
;
123 (*invalidatepage
)(page
, offset
, length
);
127 * If truncate cannot remove the fs-private metadata from the page, the page
128 * becomes orphaned. It will be left on the LRU and may even be mapped into
129 * user pagetables if we're racing with filemap_fault().
131 * We need to bale out if page->mapping is no longer equal to the original
132 * mapping. This happens a) when the VM reclaimed the page while we waited on
133 * its lock, b) when a concurrent invalidate_mapping_pages got there first and
134 * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
137 truncate_complete_page(struct address_space
*mapping
, struct page
*page
)
139 if (page
->mapping
!= mapping
)
142 if (page_has_private(page
))
143 do_invalidatepage(page
, 0, PAGE_SIZE
);
146 * Some filesystems seem to re-dirty the page even after
147 * the VM has canceled the dirty bit (eg ext3 journaling).
148 * Hence dirty accounting check is placed after invalidation.
150 cancel_dirty_page(page
);
151 ClearPageMappedToDisk(page
);
152 delete_from_page_cache(page
);
157 * This is for invalidate_mapping_pages(). That function can be called at
158 * any time, and is not supposed to throw away dirty pages. But pages can
159 * be marked dirty at any time too, so use remove_mapping which safely
160 * discards clean, unused pages.
162 * Returns non-zero if the page was successfully invalidated.
165 invalidate_complete_page(struct address_space
*mapping
, struct page
*page
)
169 if (page
->mapping
!= mapping
)
172 if (page_has_private(page
) && !try_to_release_page(page
, 0))
175 ret
= remove_mapping(mapping
, page
);
180 int truncate_inode_page(struct address_space
*mapping
, struct page
*page
)
183 VM_BUG_ON_PAGE(PageTail(page
), page
);
185 holelen
= PageTransHuge(page
) ? HPAGE_PMD_SIZE
: PAGE_SIZE
;
186 if (page_mapped(page
)) {
187 unmap_mapping_range(mapping
,
188 (loff_t
)page
->index
<< PAGE_SHIFT
,
191 return truncate_complete_page(mapping
, page
);
195 * Used to get rid of pages on hardware memory corruption.
197 int generic_error_remove_page(struct address_space
*mapping
, struct page
*page
)
202 * Only punch for normal data pages for now.
203 * Handling other types like directories would need more auditing.
205 if (!S_ISREG(mapping
->host
->i_mode
))
207 return truncate_inode_page(mapping
, page
);
209 EXPORT_SYMBOL(generic_error_remove_page
);
212 * Safely invalidate one page from its pagecache mapping.
213 * It only drops clean, unused pages. The page must be locked.
215 * Returns 1 if the page is successfully invalidated, otherwise 0.
217 int invalidate_inode_page(struct page
*page
)
219 struct address_space
*mapping
= page_mapping(page
);
222 if (PageDirty(page
) || PageWriteback(page
))
224 if (page_mapped(page
))
226 return invalidate_complete_page(mapping
, page
);
230 * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets
231 * @mapping: mapping to truncate
232 * @lstart: offset from which to truncate
233 * @lend: offset to which to truncate (inclusive)
235 * Truncate the page cache, removing the pages that are between
236 * specified offsets (and zeroing out partial pages
237 * if lstart or lend + 1 is not page aligned).
239 * Truncate takes two passes - the first pass is nonblocking. It will not
240 * block on page locks and it will not block on writeback. The second pass
241 * will wait. This is to prevent as much IO as possible in the affected region.
242 * The first pass will remove most pages, so the search cost of the second pass
245 * We pass down the cache-hot hint to the page freeing code. Even if the
246 * mapping is large, it is probably the case that the final pages are the most
247 * recently touched, and freeing happens in ascending file offset order.
249 * Note that since ->invalidatepage() accepts range to invalidate
250 * truncate_inode_pages_range is able to handle cases where lend + 1 is not
251 * page aligned properly.
253 void truncate_inode_pages_range(struct address_space
*mapping
,
254 loff_t lstart
, loff_t lend
)
256 pgoff_t start
; /* inclusive */
257 pgoff_t end
; /* exclusive */
258 unsigned int partial_start
; /* inclusive */
259 unsigned int partial_end
; /* exclusive */
261 pgoff_t indices
[PAGEVEC_SIZE
];
265 cleancache_invalidate_inode(mapping
);
266 if (mapping
->nrpages
== 0 && mapping
->nrexceptional
== 0)
269 /* Offsets within partial pages */
270 partial_start
= lstart
& (PAGE_SIZE
- 1);
271 partial_end
= (lend
+ 1) & (PAGE_SIZE
- 1);
274 * 'start' and 'end' always covers the range of pages to be fully
275 * truncated. Partial pages are covered with 'partial_start' at the
276 * start of the range and 'partial_end' at the end of the range.
277 * Note that 'end' is exclusive while 'lend' is inclusive.
279 start
= (lstart
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
282 * lend == -1 indicates end-of-file so we have to set 'end'
283 * to the highest possible pgoff_t and since the type is
284 * unsigned we're using -1.
288 end
= (lend
+ 1) >> PAGE_SHIFT
;
290 pagevec_init(&pvec
, 0);
292 while (index
< end
&& pagevec_lookup_entries(&pvec
, mapping
, index
,
293 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
),
295 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
296 struct page
*page
= pvec
.pages
[i
];
298 /* We rely upon deletion not changing page->index */
303 if (radix_tree_exceptional_entry(page
)) {
304 truncate_exceptional_entry(mapping
, index
,
309 if (!trylock_page(page
))
311 WARN_ON(page_to_index(page
) != index
);
312 if (PageWriteback(page
)) {
316 truncate_inode_page(mapping
, page
);
319 pagevec_remove_exceptionals(&pvec
);
320 pagevec_release(&pvec
);
326 struct page
*page
= find_lock_page(mapping
, start
- 1);
328 unsigned int top
= PAGE_SIZE
;
330 /* Truncation within a single page */
334 wait_on_page_writeback(page
);
335 zero_user_segment(page
, partial_start
, top
);
336 cleancache_invalidate_page(mapping
, page
);
337 if (page_has_private(page
))
338 do_invalidatepage(page
, partial_start
,
339 top
- partial_start
);
345 struct page
*page
= find_lock_page(mapping
, end
);
347 wait_on_page_writeback(page
);
348 zero_user_segment(page
, 0, partial_end
);
349 cleancache_invalidate_page(mapping
, page
);
350 if (page_has_private(page
))
351 do_invalidatepage(page
, 0,
358 * If the truncation happened within a single page no pages
359 * will be released, just zeroed, so we can bail out now.
367 if (!pagevec_lookup_entries(&pvec
, mapping
, index
,
368 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
), indices
)) {
369 /* If all gone from start onwards, we're done */
372 /* Otherwise restart to make sure all gone */
376 if (index
== start
&& indices
[0] >= end
) {
377 /* All gone out of hole to be punched, we're done */
378 pagevec_remove_exceptionals(&pvec
);
379 pagevec_release(&pvec
);
382 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
383 struct page
*page
= pvec
.pages
[i
];
385 /* We rely upon deletion not changing page->index */
388 /* Restart punch to make sure all gone */
393 if (radix_tree_exceptional_entry(page
)) {
394 truncate_exceptional_entry(mapping
, index
,
400 WARN_ON(page_to_index(page
) != index
);
401 wait_on_page_writeback(page
);
402 truncate_inode_page(mapping
, page
);
405 pagevec_remove_exceptionals(&pvec
);
406 pagevec_release(&pvec
);
409 cleancache_invalidate_inode(mapping
);
411 EXPORT_SYMBOL(truncate_inode_pages_range
);
414 * truncate_inode_pages - truncate *all* the pages from an offset
415 * @mapping: mapping to truncate
416 * @lstart: offset from which to truncate
418 * Called under (and serialised by) inode->i_mutex.
420 * Note: When this function returns, there can be a page in the process of
421 * deletion (inside __delete_from_page_cache()) in the specified range. Thus
422 * mapping->nrpages can be non-zero when this function returns even after
423 * truncation of the whole mapping.
425 void truncate_inode_pages(struct address_space
*mapping
, loff_t lstart
)
427 truncate_inode_pages_range(mapping
, lstart
, (loff_t
)-1);
429 EXPORT_SYMBOL(truncate_inode_pages
);
432 * truncate_inode_pages_final - truncate *all* pages before inode dies
433 * @mapping: mapping to truncate
435 * Called under (and serialized by) inode->i_mutex.
437 * Filesystems have to use this in the .evict_inode path to inform the
438 * VM that this is the final truncate and the inode is going away.
440 void truncate_inode_pages_final(struct address_space
*mapping
)
442 unsigned long nrexceptional
;
443 unsigned long nrpages
;
446 * Page reclaim can not participate in regular inode lifetime
447 * management (can't call iput()) and thus can race with the
448 * inode teardown. Tell it when the address space is exiting,
449 * so that it does not install eviction information after the
450 * final truncate has begun.
452 mapping_set_exiting(mapping
);
455 * When reclaim installs eviction entries, it increases
456 * nrexceptional first, then decreases nrpages. Make sure we see
457 * this in the right order or we might miss an entry.
459 nrpages
= mapping
->nrpages
;
461 nrexceptional
= mapping
->nrexceptional
;
463 if (nrpages
|| nrexceptional
) {
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.
470 spin_lock_irq(&mapping
->tree_lock
);
471 spin_unlock_irq(&mapping
->tree_lock
);
473 truncate_inode_pages(mapping
, 0);
476 EXPORT_SYMBOL(truncate_inode_pages_final
);
479 * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
480 * @mapping: the address_space which holds the pages to invalidate
481 * @start: the offset 'from' which to invalidate
482 * @end: the offset 'to' which to invalidate (inclusive)
484 * This function only removes the unlocked pages, if you want to
485 * remove all the pages of one inode, you must call truncate_inode_pages.
487 * invalidate_mapping_pages() will not block on IO activity. It will not
488 * invalidate pages which are dirty, locked, under writeback or mapped into
491 unsigned long invalidate_mapping_pages(struct address_space
*mapping
,
492 pgoff_t start
, pgoff_t end
)
494 pgoff_t indices
[PAGEVEC_SIZE
];
496 pgoff_t index
= start
;
498 unsigned long count
= 0;
501 pagevec_init(&pvec
, 0);
502 while (index
<= end
&& pagevec_lookup_entries(&pvec
, mapping
, index
,
503 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
- 1) + 1,
505 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
506 struct page
*page
= pvec
.pages
[i
];
508 /* We rely upon deletion not changing page->index */
513 if (radix_tree_exceptional_entry(page
)) {
514 invalidate_exceptional_entry(mapping
, index
,
519 if (!trylock_page(page
))
522 WARN_ON(page_to_index(page
) != index
);
524 /* Middle of THP: skip */
525 if (PageTransTail(page
)) {
528 } else if (PageTransHuge(page
)) {
529 index
+= HPAGE_PMD_NR
- 1;
530 i
+= HPAGE_PMD_NR
- 1;
531 /* 'end' is in the middle of THP */
532 if (index
== round_down(end
, HPAGE_PMD_NR
))
536 ret
= invalidate_inode_page(page
);
539 * Invalidation is a hint that the page is no longer
540 * of interest and try to speed up its reclaim.
543 deactivate_file_page(page
);
546 pagevec_remove_exceptionals(&pvec
);
547 pagevec_release(&pvec
);
553 EXPORT_SYMBOL(invalidate_mapping_pages
);
556 * This is like invalidate_complete_page(), except it ignores the page's
557 * refcount. We do this because invalidate_inode_pages2() needs stronger
558 * invalidation guarantees, and cannot afford to leave pages behind because
559 * shrink_page_list() has a temp ref on them, or because they're transiently
560 * sitting in the lru_cache_add() pagevecs.
563 invalidate_complete_page2(struct address_space
*mapping
, struct page
*page
)
567 if (page
->mapping
!= mapping
)
570 if (page_has_private(page
) && !try_to_release_page(page
, GFP_KERNEL
))
573 spin_lock_irqsave(&mapping
->tree_lock
, flags
);
577 BUG_ON(page_has_private(page
));
578 __delete_from_page_cache(page
, NULL
);
579 spin_unlock_irqrestore(&mapping
->tree_lock
, flags
);
581 if (mapping
->a_ops
->freepage
)
582 mapping
->a_ops
->freepage(page
);
584 put_page(page
); /* pagecache ref */
587 spin_unlock_irqrestore(&mapping
->tree_lock
, flags
);
591 static int do_launder_page(struct address_space
*mapping
, struct page
*page
)
593 if (!PageDirty(page
))
595 if (page
->mapping
!= mapping
|| mapping
->a_ops
->launder_page
== NULL
)
597 return mapping
->a_ops
->launder_page(page
);
601 * invalidate_inode_pages2_range - remove range of pages from an address_space
602 * @mapping: the address_space
603 * @start: the page offset 'from' which to invalidate
604 * @end: the page offset 'to' which to invalidate (inclusive)
606 * Any pages which are found to be mapped into pagetables are unmapped prior to
609 * Returns -EBUSY if any pages could not be invalidated.
611 int invalidate_inode_pages2_range(struct address_space
*mapping
,
612 pgoff_t start
, pgoff_t end
)
614 pgoff_t indices
[PAGEVEC_SIZE
];
620 int did_range_unmap
= 0;
622 cleancache_invalidate_inode(mapping
);
623 pagevec_init(&pvec
, 0);
625 while (index
<= end
&& pagevec_lookup_entries(&pvec
, mapping
, index
,
626 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
- 1) + 1,
628 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
629 struct page
*page
= pvec
.pages
[i
];
631 /* We rely upon deletion not changing page->index */
636 if (radix_tree_exceptional_entry(page
)) {
637 if (!invalidate_exceptional_entry2(mapping
,
644 WARN_ON(page_to_index(page
) != index
);
645 if (page
->mapping
!= mapping
) {
649 wait_on_page_writeback(page
);
650 if (page_mapped(page
)) {
651 if (!did_range_unmap
) {
653 * Zap the rest of the file in one hit.
655 unmap_mapping_range(mapping
,
656 (loff_t
)index
<< PAGE_SHIFT
,
657 (loff_t
)(1 + end
- index
)
665 unmap_mapping_range(mapping
,
666 (loff_t
)index
<< PAGE_SHIFT
,
670 BUG_ON(page_mapped(page
));
671 ret2
= do_launder_page(mapping
, page
);
673 if (!invalidate_complete_page2(mapping
, page
))
680 pagevec_remove_exceptionals(&pvec
);
681 pagevec_release(&pvec
);
686 * For DAX we invalidate page tables after invalidating radix tree. We
687 * could invalidate page tables while invalidating each entry however
688 * that would be expensive. And doing range unmapping before doesn't
689 * work as we have no cheap way to find whether radix tree entry didn't
690 * get remapped later.
692 if (dax_mapping(mapping
)) {
693 unmap_mapping_range(mapping
, (loff_t
)start
<< PAGE_SHIFT
,
694 (loff_t
)(end
- start
+ 1) << PAGE_SHIFT
, 0);
696 cleancache_invalidate_inode(mapping
);
699 EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range
);
702 * invalidate_inode_pages2 - remove all pages from an address_space
703 * @mapping: the address_space
705 * Any pages which are found to be mapped into pagetables are unmapped prior to
708 * Returns -EBUSY if any pages could not be invalidated.
710 int invalidate_inode_pages2(struct address_space
*mapping
)
712 return invalidate_inode_pages2_range(mapping
, 0, -1);
714 EXPORT_SYMBOL_GPL(invalidate_inode_pages2
);
717 * truncate_pagecache - unmap and remove pagecache that has been truncated
719 * @newsize: new file size
721 * inode's new i_size must already be written before truncate_pagecache
724 * This function should typically be called before the filesystem
725 * releases resources associated with the freed range (eg. deallocates
726 * blocks). This way, pagecache will always stay logically coherent
727 * with on-disk format, and the filesystem would not have to deal with
728 * situations such as writepage being called for a page that has already
729 * had its underlying blocks deallocated.
731 void truncate_pagecache(struct inode
*inode
, loff_t newsize
)
733 struct address_space
*mapping
= inode
->i_mapping
;
734 loff_t holebegin
= round_up(newsize
, PAGE_SIZE
);
737 * unmap_mapping_range is called twice, first simply for
738 * efficiency so that truncate_inode_pages does fewer
739 * single-page unmaps. However after this first call, and
740 * before truncate_inode_pages finishes, it is possible for
741 * private pages to be COWed, which remain after
742 * truncate_inode_pages finishes, hence the second
743 * unmap_mapping_range call must be made for correctness.
745 unmap_mapping_range(mapping
, holebegin
, 0, 1);
746 truncate_inode_pages(mapping
, newsize
);
747 unmap_mapping_range(mapping
, holebegin
, 0, 1);
749 EXPORT_SYMBOL(truncate_pagecache
);
752 * truncate_setsize - update inode and pagecache for a new file size
754 * @newsize: new file size
756 * truncate_setsize updates i_size and performs pagecache truncation (if
757 * necessary) to @newsize. It will be typically be called from the filesystem's
758 * setattr function when ATTR_SIZE is passed in.
760 * Must be called with a lock serializing truncates and writes (generally
761 * i_mutex but e.g. xfs uses a different lock) and before all filesystem
762 * specific block truncation has been performed.
764 void truncate_setsize(struct inode
*inode
, loff_t newsize
)
766 loff_t oldsize
= inode
->i_size
;
768 i_size_write(inode
, newsize
);
769 if (newsize
> oldsize
)
770 pagecache_isize_extended(inode
, oldsize
, newsize
);
771 truncate_pagecache(inode
, newsize
);
773 EXPORT_SYMBOL(truncate_setsize
);
776 * pagecache_isize_extended - update pagecache after extension of i_size
777 * @inode: inode for which i_size was extended
778 * @from: original inode size
779 * @to: new inode size
781 * Handle extension of inode size either caused by extending truncate or by
782 * write starting after current i_size. We mark the page straddling current
783 * i_size RO so that page_mkwrite() is called on the nearest write access to
784 * the page. This way filesystem can be sure that page_mkwrite() is called on
785 * the page before user writes to the page via mmap after the i_size has been
788 * The function must be called after i_size is updated so that page fault
789 * coming after we unlock the page will already see the new i_size.
790 * The function must be called while we still hold i_mutex - this not only
791 * makes sure i_size is stable but also that userspace cannot observe new
792 * i_size value before we are prepared to store mmap writes at new inode size.
794 void pagecache_isize_extended(struct inode
*inode
, loff_t from
, loff_t to
)
796 int bsize
= 1 << inode
->i_blkbits
;
801 WARN_ON(to
> inode
->i_size
);
803 if (from
>= to
|| bsize
== PAGE_SIZE
)
805 /* Page straddling @from will not have any hole block created? */
806 rounded_from
= round_up(from
, bsize
);
807 if (to
<= rounded_from
|| !(rounded_from
& (PAGE_SIZE
- 1)))
810 index
= from
>> PAGE_SHIFT
;
811 page
= find_lock_page(inode
->i_mapping
, index
);
812 /* Page not cached? Nothing to do */
816 * See clear_page_dirty_for_io() for details why set_page_dirty()
819 if (page_mkclean(page
))
820 set_page_dirty(page
);
824 EXPORT_SYMBOL(pagecache_isize_extended
);
827 * truncate_pagecache_range - unmap and remove pagecache that is hole-punched
829 * @lstart: offset of beginning of hole
830 * @lend: offset of last byte of hole
832 * This function should typically be called before the filesystem
833 * releases resources associated with the freed range (eg. deallocates
834 * blocks). This way, pagecache will always stay logically coherent
835 * with on-disk format, and the filesystem would not have to deal with
836 * situations such as writepage being called for a page that has already
837 * had its underlying blocks deallocated.
839 void truncate_pagecache_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
841 struct address_space
*mapping
= inode
->i_mapping
;
842 loff_t unmap_start
= round_up(lstart
, PAGE_SIZE
);
843 loff_t unmap_end
= round_down(1 + lend
, PAGE_SIZE
) - 1;
845 * This rounding is currently just for example: unmap_mapping_range
846 * expands its hole outwards, whereas we want it to contract the hole
847 * inwards. However, existing callers of truncate_pagecache_range are
848 * doing their own page rounding first. Note that unmap_mapping_range
849 * allows holelen 0 for all, and we allow lend -1 for end of file.
853 * Unlike in truncate_pagecache, unmap_mapping_range is called only
854 * once (before truncating pagecache), and without "even_cows" flag:
855 * hole-punching should not remove private COWed pages from the hole.
857 if ((u64
)unmap_end
> (u64
)unmap_start
)
858 unmap_mapping_range(mapping
, unmap_start
,
859 1 + unmap_end
- unmap_start
, 0);
860 truncate_inode_pages_range(mapping
, lstart
, lend
);
862 EXPORT_SYMBOL(truncate_pagecache_range
);