1 // SPDX-License-Identifier: GPL-2.0-only
3 * mm/truncate.c - code for taking down pages from address_spaces
5 * Copyright (C) 2002, Linus Torvalds
7 * 10Sep2002 Andrew Morton
11 #include <linux/kernel.h>
12 #include <linux/backing-dev.h>
13 #include <linux/dax.h>
14 #include <linux/gfp.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 #include <linux/shmem_fs.h>
24 #include <linux/rmap.h>
28 * Regular page slots are stabilized by the page lock even without the tree
29 * itself locked. These unlocked entries need verification under the tree
32 static inline void __clear_shadow_entry(struct address_space
*mapping
,
33 pgoff_t index
, void *entry
)
35 XA_STATE(xas
, &mapping
->i_pages
, index
);
37 xas_set_update(&xas
, workingset_update_node
);
38 if (xas_load(&xas
) != entry
)
40 xas_store(&xas
, NULL
);
43 static void clear_shadow_entry(struct address_space
*mapping
, pgoff_t index
,
46 spin_lock(&mapping
->host
->i_lock
);
47 xa_lock_irq(&mapping
->i_pages
);
48 __clear_shadow_entry(mapping
, index
, entry
);
49 xa_unlock_irq(&mapping
->i_pages
);
50 if (mapping_shrinkable(mapping
))
51 inode_add_lru(mapping
->host
);
52 spin_unlock(&mapping
->host
->i_lock
);
56 * Unconditionally remove exceptional entries. Usually called from truncate
57 * path. Note that the folio_batch may be altered by this function by removing
58 * exceptional entries similar to what folio_batch_remove_exceptionals() does.
60 static void truncate_folio_batch_exceptionals(struct address_space
*mapping
,
61 struct folio_batch
*fbatch
, pgoff_t
*indices
)
66 /* Handled by shmem itself */
67 if (shmem_mapping(mapping
))
70 for (j
= 0; j
< folio_batch_count(fbatch
); j
++)
71 if (xa_is_value(fbatch
->folios
[j
]))
74 if (j
== folio_batch_count(fbatch
))
77 dax
= dax_mapping(mapping
);
79 spin_lock(&mapping
->host
->i_lock
);
80 xa_lock_irq(&mapping
->i_pages
);
83 for (i
= j
; i
< folio_batch_count(fbatch
); i
++) {
84 struct folio
*folio
= fbatch
->folios
[i
];
85 pgoff_t index
= indices
[i
];
87 if (!xa_is_value(folio
)) {
88 fbatch
->folios
[j
++] = folio
;
93 dax_delete_mapping_entry(mapping
, index
);
97 __clear_shadow_entry(mapping
, index
, folio
);
101 xa_unlock_irq(&mapping
->i_pages
);
102 if (mapping_shrinkable(mapping
))
103 inode_add_lru(mapping
->host
);
104 spin_unlock(&mapping
->host
->i_lock
);
110 * Invalidate exceptional entry if easily possible. This handles exceptional
111 * entries for invalidate_inode_pages().
113 static int invalidate_exceptional_entry(struct address_space
*mapping
,
114 pgoff_t index
, void *entry
)
116 /* Handled by shmem itself, or for DAX we do nothing. */
117 if (shmem_mapping(mapping
) || dax_mapping(mapping
))
119 clear_shadow_entry(mapping
, index
, entry
);
124 * Invalidate exceptional entry if clean. This handles exceptional entries for
125 * invalidate_inode_pages2() so for DAX it evicts only clean entries.
127 static int invalidate_exceptional_entry2(struct address_space
*mapping
,
128 pgoff_t index
, void *entry
)
130 /* Handled by shmem itself */
131 if (shmem_mapping(mapping
))
133 if (dax_mapping(mapping
))
134 return dax_invalidate_mapping_entry_sync(mapping
, index
);
135 clear_shadow_entry(mapping
, index
, entry
);
140 * folio_invalidate - Invalidate part or all of a folio.
141 * @folio: The folio which is affected.
142 * @offset: start of the range to invalidate
143 * @length: length of the range to invalidate
145 * folio_invalidate() is called when all or part of the folio has become
146 * invalidated by a truncate operation.
148 * folio_invalidate() does not have to release all buffers, but it must
149 * ensure that no dirty buffer is left outside @offset and that no I/O
150 * is underway against any of the blocks which are outside the truncation
151 * point. Because the caller is about to free (and possibly reuse) those
154 void folio_invalidate(struct folio
*folio
, size_t offset
, size_t length
)
156 const struct address_space_operations
*aops
= folio
->mapping
->a_ops
;
158 if (aops
->invalidate_folio
)
159 aops
->invalidate_folio(folio
, offset
, length
);
161 EXPORT_SYMBOL_GPL(folio_invalidate
);
164 * If truncate cannot remove the fs-private metadata from the page, the page
165 * becomes orphaned. It will be left on the LRU and may even be mapped into
166 * user pagetables if we're racing with filemap_fault().
168 * We need to bail out if page->mapping is no longer equal to the original
169 * mapping. This happens a) when the VM reclaimed the page while we waited on
170 * its lock, b) when a concurrent invalidate_mapping_pages got there first and
171 * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
173 static void truncate_cleanup_folio(struct folio
*folio
)
175 if (folio_mapped(folio
))
176 unmap_mapping_folio(folio
);
178 if (folio_has_private(folio
))
179 folio_invalidate(folio
, 0, folio_size(folio
));
182 * Some filesystems seem to re-dirty the page even after
183 * the VM has canceled the dirty bit (eg ext3 journaling).
184 * Hence dirty accounting check is placed after invalidation.
186 folio_cancel_dirty(folio
);
187 folio_clear_mappedtodisk(folio
);
190 int truncate_inode_folio(struct address_space
*mapping
, struct folio
*folio
)
192 if (folio
->mapping
!= mapping
)
195 truncate_cleanup_folio(folio
);
196 filemap_remove_folio(folio
);
201 * Handle partial folios. The folio may be entirely within the
202 * range if a split has raced with us. If not, we zero the part of the
203 * folio that's within the [start, end] range, and then split the folio if
204 * it's large. split_page_range() will discard pages which now lie beyond
205 * i_size, and we rely on the caller to discard pages which lie within a
206 * newly created hole.
208 * Returns false if splitting failed so the caller can avoid
209 * discarding the entire folio which is stubbornly unsplit.
211 bool truncate_inode_partial_folio(struct folio
*folio
, loff_t start
, loff_t end
)
213 loff_t pos
= folio_pos(folio
);
214 unsigned int offset
, length
;
217 offset
= start
- pos
;
220 length
= folio_size(folio
);
221 if (pos
+ length
<= (u64
)end
)
222 length
= length
- offset
;
224 length
= end
+ 1 - pos
- offset
;
226 folio_wait_writeback(folio
);
227 if (length
== folio_size(folio
)) {
228 truncate_inode_folio(folio
->mapping
, folio
);
233 * We may be zeroing pages we're about to discard, but it avoids
234 * doing a complex calculation here, and then doing the zeroing
235 * anyway if the page split fails.
237 folio_zero_range(folio
, offset
, length
);
239 if (folio_has_private(folio
))
240 folio_invalidate(folio
, offset
, length
);
241 if (!folio_test_large(folio
))
243 if (split_folio(folio
) == 0)
245 if (folio_test_dirty(folio
))
247 truncate_inode_folio(folio
->mapping
, folio
);
252 * Used to get rid of pages on hardware memory corruption.
254 int generic_error_remove_page(struct address_space
*mapping
, struct page
*page
)
256 VM_BUG_ON_PAGE(PageTail(page
), page
);
261 * Only punch for normal data pages for now.
262 * Handling other types like directories would need more auditing.
264 if (!S_ISREG(mapping
->host
->i_mode
))
266 return truncate_inode_folio(mapping
, page_folio(page
));
268 EXPORT_SYMBOL(generic_error_remove_page
);
270 static long mapping_evict_folio(struct address_space
*mapping
,
273 if (folio_test_dirty(folio
) || folio_test_writeback(folio
))
275 /* The refcount will be elevated if any page in the folio is mapped */
276 if (folio_ref_count(folio
) >
277 folio_nr_pages(folio
) + folio_has_private(folio
) + 1)
279 if (folio_has_private(folio
) && !filemap_release_folio(folio
, 0))
282 return remove_mapping(mapping
, folio
);
286 * invalidate_inode_page() - Remove an unused page from the pagecache.
287 * @page: The page to remove.
289 * Safely invalidate one page from its pagecache mapping.
290 * It only drops clean, unused pages.
292 * Context: Page must be locked.
293 * Return: The number of pages successfully removed.
295 long invalidate_inode_page(struct page
*page
)
297 struct folio
*folio
= page_folio(page
);
298 struct address_space
*mapping
= folio_mapping(folio
);
300 /* The page may have been truncated before it was locked */
303 return mapping_evict_folio(mapping
, folio
);
307 * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets
308 * @mapping: mapping to truncate
309 * @lstart: offset from which to truncate
310 * @lend: offset to which to truncate (inclusive)
312 * Truncate the page cache, removing the pages that are between
313 * specified offsets (and zeroing out partial pages
314 * if lstart or lend + 1 is not page aligned).
316 * Truncate takes two passes - the first pass is nonblocking. It will not
317 * block on page locks and it will not block on writeback. The second pass
318 * will wait. This is to prevent as much IO as possible in the affected region.
319 * The first pass will remove most pages, so the search cost of the second pass
322 * We pass down the cache-hot hint to the page freeing code. Even if the
323 * mapping is large, it is probably the case that the final pages are the most
324 * recently touched, and freeing happens in ascending file offset order.
326 * Note that since ->invalidate_folio() accepts range to invalidate
327 * truncate_inode_pages_range is able to handle cases where lend + 1 is not
328 * page aligned properly.
330 void truncate_inode_pages_range(struct address_space
*mapping
,
331 loff_t lstart
, loff_t lend
)
333 pgoff_t start
; /* inclusive */
334 pgoff_t end
; /* exclusive */
335 struct folio_batch fbatch
;
336 pgoff_t indices
[PAGEVEC_SIZE
];
342 if (mapping_empty(mapping
))
346 * 'start' and 'end' always covers the range of pages to be fully
347 * truncated. Partial pages are covered with 'partial_start' at the
348 * start of the range and 'partial_end' at the end of the range.
349 * Note that 'end' is exclusive while 'lend' is inclusive.
351 start
= (lstart
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
354 * lend == -1 indicates end-of-file so we have to set 'end'
355 * to the highest possible pgoff_t and since the type is
356 * unsigned we're using -1.
360 end
= (lend
+ 1) >> PAGE_SHIFT
;
362 folio_batch_init(&fbatch
);
364 while (index
< end
&& find_lock_entries(mapping
, index
, end
- 1,
366 index
= indices
[folio_batch_count(&fbatch
) - 1] + 1;
367 truncate_folio_batch_exceptionals(mapping
, &fbatch
, indices
);
368 for (i
= 0; i
< folio_batch_count(&fbatch
); i
++)
369 truncate_cleanup_folio(fbatch
.folios
[i
]);
370 delete_from_page_cache_batch(mapping
, &fbatch
);
371 for (i
= 0; i
< folio_batch_count(&fbatch
); i
++)
372 folio_unlock(fbatch
.folios
[i
]);
373 folio_batch_release(&fbatch
);
377 same_folio
= (lstart
>> PAGE_SHIFT
) == (lend
>> PAGE_SHIFT
);
378 folio
= __filemap_get_folio(mapping
, lstart
>> PAGE_SHIFT
, FGP_LOCK
, 0);
380 same_folio
= lend
< folio_pos(folio
) + folio_size(folio
);
381 if (!truncate_inode_partial_folio(folio
, lstart
, lend
)) {
382 start
= folio
->index
+ folio_nr_pages(folio
);
392 folio
= __filemap_get_folio(mapping
, lend
>> PAGE_SHIFT
,
395 if (!truncate_inode_partial_folio(folio
, lstart
, lend
))
402 while (index
< end
) {
404 if (!find_get_entries(mapping
, index
, end
- 1, &fbatch
,
406 /* If all gone from start onwards, we're done */
409 /* Otherwise restart to make sure all gone */
414 for (i
= 0; i
< folio_batch_count(&fbatch
); i
++) {
415 struct folio
*folio
= fbatch
.folios
[i
];
417 /* We rely upon deletion not changing page->index */
420 if (xa_is_value(folio
))
424 VM_BUG_ON_FOLIO(!folio_contains(folio
, index
), folio
);
425 folio_wait_writeback(folio
);
426 truncate_inode_folio(mapping
, folio
);
428 index
= folio_index(folio
) + folio_nr_pages(folio
) - 1;
430 truncate_folio_batch_exceptionals(mapping
, &fbatch
, indices
);
431 folio_batch_release(&fbatch
);
435 EXPORT_SYMBOL(truncate_inode_pages_range
);
438 * truncate_inode_pages - truncate *all* the pages from an offset
439 * @mapping: mapping to truncate
440 * @lstart: offset from which to truncate
442 * Called under (and serialised by) inode->i_rwsem and
443 * mapping->invalidate_lock.
445 * Note: When this function returns, there can be a page in the process of
446 * deletion (inside __filemap_remove_folio()) in the specified range. Thus
447 * mapping->nrpages can be non-zero when this function returns even after
448 * truncation of the whole mapping.
450 void truncate_inode_pages(struct address_space
*mapping
, loff_t lstart
)
452 truncate_inode_pages_range(mapping
, lstart
, (loff_t
)-1);
454 EXPORT_SYMBOL(truncate_inode_pages
);
457 * truncate_inode_pages_final - truncate *all* pages before inode dies
458 * @mapping: mapping to truncate
460 * Called under (and serialized by) inode->i_rwsem.
462 * Filesystems have to use this in the .evict_inode path to inform the
463 * VM that this is the final truncate and the inode is going away.
465 void truncate_inode_pages_final(struct address_space
*mapping
)
468 * Page reclaim can not participate in regular inode lifetime
469 * management (can't call iput()) and thus can race with the
470 * inode teardown. Tell it when the address space is exiting,
471 * so that it does not install eviction information after the
472 * final truncate has begun.
474 mapping_set_exiting(mapping
);
476 if (!mapping_empty(mapping
)) {
478 * As truncation uses a lockless tree lookup, cycle
479 * the tree lock to make sure any ongoing tree
480 * modification that does not see AS_EXITING is
481 * completed before starting the final truncate.
483 xa_lock_irq(&mapping
->i_pages
);
484 xa_unlock_irq(&mapping
->i_pages
);
487 truncate_inode_pages(mapping
, 0);
489 EXPORT_SYMBOL(truncate_inode_pages_final
);
492 * invalidate_mapping_pagevec - Invalidate all the unlocked pages of one inode
493 * @mapping: the address_space which holds the pages to invalidate
494 * @start: the offset 'from' which to invalidate
495 * @end: the offset 'to' which to invalidate (inclusive)
496 * @nr_pagevec: invalidate failed page number for caller
498 * This helper is similar to invalidate_mapping_pages(), except that it accounts
499 * for pages that are likely on a pagevec and counts them in @nr_pagevec, which
500 * will be used by the caller.
502 unsigned long invalidate_mapping_pagevec(struct address_space
*mapping
,
503 pgoff_t start
, pgoff_t end
, unsigned long *nr_pagevec
)
505 pgoff_t indices
[PAGEVEC_SIZE
];
506 struct folio_batch fbatch
;
507 pgoff_t index
= start
;
509 unsigned long count
= 0;
512 folio_batch_init(&fbatch
);
513 while (find_lock_entries(mapping
, index
, end
, &fbatch
, indices
)) {
514 for (i
= 0; i
< folio_batch_count(&fbatch
); i
++) {
515 struct folio
*folio
= fbatch
.folios
[i
];
517 /* We rely upon deletion not changing folio->index */
520 if (xa_is_value(folio
)) {
521 count
+= invalidate_exceptional_entry(mapping
,
526 index
+= folio_nr_pages(folio
) - 1;
528 ret
= mapping_evict_folio(mapping
, folio
);
531 * Invalidation is a hint that the folio is no longer
532 * of interest and try to speed up its reclaim.
535 deactivate_file_folio(folio
);
536 /* It is likely on the pagevec of a remote CPU */
542 folio_batch_remove_exceptionals(&fbatch
);
543 folio_batch_release(&fbatch
);
551 * invalidate_mapping_pages - Invalidate all clean, unlocked cache of one inode
552 * @mapping: the address_space which holds the cache to invalidate
553 * @start: the offset 'from' which to invalidate
554 * @end: the offset 'to' which to invalidate (inclusive)
556 * This function removes pages that are clean, unmapped and unlocked,
557 * as well as shadow entries. It will not block on IO activity.
559 * If you want to remove all the pages of one inode, regardless of
560 * their use and writeback state, use truncate_inode_pages().
562 * Return: the number of the cache entries that were invalidated
564 unsigned long invalidate_mapping_pages(struct address_space
*mapping
,
565 pgoff_t start
, pgoff_t end
)
567 return invalidate_mapping_pagevec(mapping
, start
, end
, NULL
);
569 EXPORT_SYMBOL(invalidate_mapping_pages
);
572 * This is like invalidate_inode_page(), except it ignores the page's
573 * refcount. We do this because invalidate_inode_pages2() needs stronger
574 * invalidation guarantees, and cannot afford to leave pages behind because
575 * shrink_page_list() has a temp ref on them, or because they're transiently
576 * sitting in the lru_cache_add() pagevecs.
578 static int invalidate_complete_folio2(struct address_space
*mapping
,
581 if (folio
->mapping
!= mapping
)
584 if (folio_has_private(folio
) &&
585 !filemap_release_folio(folio
, GFP_KERNEL
))
588 spin_lock(&mapping
->host
->i_lock
);
589 xa_lock_irq(&mapping
->i_pages
);
590 if (folio_test_dirty(folio
))
593 BUG_ON(folio_has_private(folio
));
594 __filemap_remove_folio(folio
, NULL
);
595 xa_unlock_irq(&mapping
->i_pages
);
596 if (mapping_shrinkable(mapping
))
597 inode_add_lru(mapping
->host
);
598 spin_unlock(&mapping
->host
->i_lock
);
600 filemap_free_folio(mapping
, folio
);
603 xa_unlock_irq(&mapping
->i_pages
);
604 spin_unlock(&mapping
->host
->i_lock
);
608 static int folio_launder(struct address_space
*mapping
, struct folio
*folio
)
610 if (!folio_test_dirty(folio
))
612 if (folio
->mapping
!= mapping
|| mapping
->a_ops
->launder_folio
== NULL
)
614 return mapping
->a_ops
->launder_folio(folio
);
618 * invalidate_inode_pages2_range - remove range of pages from an address_space
619 * @mapping: the address_space
620 * @start: the page offset 'from' which to invalidate
621 * @end: the page offset 'to' which to invalidate (inclusive)
623 * Any pages which are found to be mapped into pagetables are unmapped prior to
626 * Return: -EBUSY if any pages could not be invalidated.
628 int invalidate_inode_pages2_range(struct address_space
*mapping
,
629 pgoff_t start
, pgoff_t end
)
631 pgoff_t indices
[PAGEVEC_SIZE
];
632 struct folio_batch fbatch
;
637 int did_range_unmap
= 0;
639 if (mapping_empty(mapping
))
642 folio_batch_init(&fbatch
);
644 while (find_get_entries(mapping
, index
, end
, &fbatch
, indices
)) {
645 for (i
= 0; i
< folio_batch_count(&fbatch
); i
++) {
646 struct folio
*folio
= fbatch
.folios
[i
];
648 /* We rely upon deletion not changing folio->index */
651 if (xa_is_value(folio
)) {
652 if (!invalidate_exceptional_entry2(mapping
,
658 if (!did_range_unmap
&& folio_mapped(folio
)) {
660 * If folio is mapped, before taking its lock,
661 * zap the rest of the file in one hit.
663 unmap_mapping_pages(mapping
, index
,
664 (1 + end
- index
), false);
669 VM_BUG_ON_FOLIO(!folio_contains(folio
, index
), folio
);
670 if (folio
->mapping
!= mapping
) {
674 folio_wait_writeback(folio
);
676 if (folio_mapped(folio
))
677 unmap_mapping_folio(folio
);
678 BUG_ON(folio_mapped(folio
));
680 ret2
= folio_launder(mapping
, folio
);
682 if (!invalidate_complete_folio2(mapping
, folio
))
689 folio_batch_remove_exceptionals(&fbatch
);
690 folio_batch_release(&fbatch
);
695 * For DAX we invalidate page tables after invalidating page cache. We
696 * could invalidate page tables while invalidating each entry however
697 * that would be expensive. And doing range unmapping before doesn't
698 * work as we have no cheap way to find whether page cache entry didn't
699 * get remapped later.
701 if (dax_mapping(mapping
)) {
702 unmap_mapping_pages(mapping
, start
, end
- start
+ 1, false);
706 EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range
);
709 * invalidate_inode_pages2 - remove all pages from an address_space
710 * @mapping: the address_space
712 * Any pages which are found to be mapped into pagetables are unmapped prior to
715 * Return: -EBUSY if any pages could not be invalidated.
717 int invalidate_inode_pages2(struct address_space
*mapping
)
719 return invalidate_inode_pages2_range(mapping
, 0, -1);
721 EXPORT_SYMBOL_GPL(invalidate_inode_pages2
);
724 * truncate_pagecache - unmap and remove pagecache that has been truncated
726 * @newsize: new file size
728 * inode's new i_size must already be written before truncate_pagecache
731 * This function should typically be called before the filesystem
732 * releases resources associated with the freed range (eg. deallocates
733 * blocks). This way, pagecache will always stay logically coherent
734 * with on-disk format, and the filesystem would not have to deal with
735 * situations such as writepage being called for a page that has already
736 * had its underlying blocks deallocated.
738 void truncate_pagecache(struct inode
*inode
, loff_t newsize
)
740 struct address_space
*mapping
= inode
->i_mapping
;
741 loff_t holebegin
= round_up(newsize
, PAGE_SIZE
);
744 * unmap_mapping_range is called twice, first simply for
745 * efficiency so that truncate_inode_pages does fewer
746 * single-page unmaps. However after this first call, and
747 * before truncate_inode_pages finishes, it is possible for
748 * private pages to be COWed, which remain after
749 * truncate_inode_pages finishes, hence the second
750 * unmap_mapping_range call must be made for correctness.
752 unmap_mapping_range(mapping
, holebegin
, 0, 1);
753 truncate_inode_pages(mapping
, newsize
);
754 unmap_mapping_range(mapping
, holebegin
, 0, 1);
756 EXPORT_SYMBOL(truncate_pagecache
);
759 * truncate_setsize - update inode and pagecache for a new file size
761 * @newsize: new file size
763 * truncate_setsize updates i_size and performs pagecache truncation (if
764 * necessary) to @newsize. It will be typically be called from the filesystem's
765 * setattr function when ATTR_SIZE is passed in.
767 * Must be called with a lock serializing truncates and writes (generally
768 * i_rwsem but e.g. xfs uses a different lock) and before all filesystem
769 * specific block truncation has been performed.
771 void truncate_setsize(struct inode
*inode
, loff_t newsize
)
773 loff_t oldsize
= inode
->i_size
;
775 i_size_write(inode
, newsize
);
776 if (newsize
> oldsize
)
777 pagecache_isize_extended(inode
, oldsize
, newsize
);
778 truncate_pagecache(inode
, newsize
);
780 EXPORT_SYMBOL(truncate_setsize
);
783 * pagecache_isize_extended - update pagecache after extension of i_size
784 * @inode: inode for which i_size was extended
785 * @from: original inode size
786 * @to: new inode size
788 * Handle extension of inode size either caused by extending truncate or by
789 * write starting after current i_size. We mark the page straddling current
790 * i_size RO so that page_mkwrite() is called on the nearest write access to
791 * the page. This way filesystem can be sure that page_mkwrite() is called on
792 * the page before user writes to the page via mmap after the i_size has been
795 * The function must be called after i_size is updated so that page fault
796 * coming after we unlock the page will already see the new i_size.
797 * The function must be called while we still hold i_rwsem - this not only
798 * makes sure i_size is stable but also that userspace cannot observe new
799 * i_size value before we are prepared to store mmap writes at new inode size.
801 void pagecache_isize_extended(struct inode
*inode
, loff_t from
, loff_t to
)
803 int bsize
= i_blocksize(inode
);
808 WARN_ON(to
> inode
->i_size
);
810 if (from
>= to
|| bsize
== PAGE_SIZE
)
812 /* Page straddling @from will not have any hole block created? */
813 rounded_from
= round_up(from
, bsize
);
814 if (to
<= rounded_from
|| !(rounded_from
& (PAGE_SIZE
- 1)))
817 index
= from
>> PAGE_SHIFT
;
818 page
= find_lock_page(inode
->i_mapping
, index
);
819 /* Page not cached? Nothing to do */
823 * See clear_page_dirty_for_io() for details why set_page_dirty()
826 if (page_mkclean(page
))
827 set_page_dirty(page
);
831 EXPORT_SYMBOL(pagecache_isize_extended
);
834 * truncate_pagecache_range - unmap and remove pagecache that is hole-punched
836 * @lstart: offset of beginning of hole
837 * @lend: offset of last byte of hole
839 * This function should typically be called before the filesystem
840 * releases resources associated with the freed range (eg. deallocates
841 * blocks). This way, pagecache will always stay logically coherent
842 * with on-disk format, and the filesystem would not have to deal with
843 * situations such as writepage being called for a page that has already
844 * had its underlying blocks deallocated.
846 void truncate_pagecache_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
848 struct address_space
*mapping
= inode
->i_mapping
;
849 loff_t unmap_start
= round_up(lstart
, PAGE_SIZE
);
850 loff_t unmap_end
= round_down(1 + lend
, PAGE_SIZE
) - 1;
852 * This rounding is currently just for example: unmap_mapping_range
853 * expands its hole outwards, whereas we want it to contract the hole
854 * inwards. However, existing callers of truncate_pagecache_range are
855 * doing their own page rounding first. Note that unmap_mapping_range
856 * allows holelen 0 for all, and we allow lend -1 for end of file.
860 * Unlike in truncate_pagecache, unmap_mapping_range is called only
861 * once (before truncating pagecache), and without "even_cows" flag:
862 * hole-punching should not remove private COWed pages from the hole.
864 if ((u64
)unmap_end
> (u64
)unmap_start
)
865 unmap_mapping_range(mapping
, unmap_start
,
866 1 + unmap_end
- unmap_start
, 0);
867 truncate_inode_pages_range(mapping
, lstart
, lend
);
869 EXPORT_SYMBOL(truncate_pagecache_range
);