Line data Source code
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 : */
34 0 : static inline void __clear_shadow_entry(struct address_space *mapping,
35 : pgoff_t index, void *entry)
36 : {
37 0 : XA_STATE(xas, &mapping->i_pages, index);
38 :
39 0 : xas_set_update(&xas, workingset_update_node);
40 0 : if (xas_load(&xas) != entry)
41 0 : return;
42 0 : xas_store(&xas, NULL);
43 0 : mapping->nrexceptional--;
44 : }
45 :
46 0 : static void clear_shadow_entry(struct address_space *mapping, pgoff_t index,
47 : void *entry)
48 : {
49 0 : xa_lock_irq(&mapping->i_pages);
50 0 : __clear_shadow_entry(mapping, index, entry);
51 0 : xa_unlock_irq(&mapping->i_pages);
52 0 : }
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 : */
59 144 : static void truncate_exceptional_pvec_entries(struct address_space *mapping,
60 : struct pagevec *pvec, pgoff_t *indices)
61 : {
62 144 : int i, j;
63 144 : bool dax;
64 :
65 : /* Handled by shmem itself */
66 144 : if (shmem_mapping(mapping))
67 : return;
68 :
69 1455 : for (j = 0; j < pagevec_count(pvec); j++)
70 1311 : if (xa_is_value(pvec->pages[j]))
71 : break;
72 :
73 144 : if (j == pagevec_count(pvec))
74 : return;
75 :
76 0 : dax = dax_mapping(mapping);
77 0 : if (!dax)
78 0 : xa_lock_irq(&mapping->i_pages);
79 :
80 0 : for (i = j; i < pagevec_count(pvec); i++) {
81 0 : struct page *page = pvec->pages[i];
82 0 : pgoff_t index = indices[i];
83 :
84 0 : if (!xa_is_value(page)) {
85 0 : pvec->pages[j++] = page;
86 0 : continue;
87 : }
88 :
89 0 : if (unlikely(dax)) {
90 : dax_delete_mapping_entry(mapping, index);
91 : continue;
92 : }
93 :
94 0 : __clear_shadow_entry(mapping, index, page);
95 : }
96 :
97 0 : if (!dax)
98 0 : xa_unlock_irq(&mapping->i_pages);
99 0 : pvec->nr = j;
100 : }
101 :
102 : /*
103 : * Invalidate exceptional entry if easily possible. This handles exceptional
104 : * entries for invalidate_inode_pages().
105 : */
106 0 : static int invalidate_exceptional_entry(struct address_space *mapping,
107 : pgoff_t index, void *entry)
108 : {
109 : /* Handled by shmem itself, or for DAX we do nothing. */
110 0 : if (shmem_mapping(mapping) || dax_mapping(mapping))
111 : return 1;
112 0 : clear_shadow_entry(mapping, index, entry);
113 0 : return 1;
114 : }
115 :
116 : /*
117 : * Invalidate exceptional entry if clean. This handles exceptional entries for
118 : * invalidate_inode_pages2() so for DAX it evicts only clean entries.
119 : */
120 0 : static int invalidate_exceptional_entry2(struct address_space *mapping,
121 : pgoff_t index, void *entry)
122 : {
123 : /* Handled by shmem itself */
124 0 : if (shmem_mapping(mapping))
125 : return 1;
126 0 : if (dax_mapping(mapping))
127 : return dax_invalidate_mapping_entry_sync(mapping, index);
128 0 : clear_shadow_entry(mapping, index, entry);
129 0 : return 1;
130 : }
131 :
132 : /**
133 : * do_invalidatepage - invalidate part or all of a page
134 : * @page: the page which is affected
135 : * @offset: start of the range to invalidate
136 : * @length: length of the range to invalidate
137 : *
138 : * do_invalidatepage() is called when all or part of the page has become
139 : * invalidated by a truncate operation.
140 : *
141 : * do_invalidatepage() does not have to release all buffers, but it must
142 : * ensure that no dirty buffer is left outside @offset and that no I/O
143 : * is underway against any of the blocks which are outside the truncation
144 : * point. Because the caller is about to free (and possibly reuse) those
145 : * blocks on-disk.
146 : */
147 501 : void do_invalidatepage(struct page *page, unsigned int offset,
148 : unsigned int length)
149 : {
150 501 : void (*invalidatepage)(struct page *, unsigned int, unsigned int);
151 :
152 501 : invalidatepage = page->mapping->a_ops->invalidatepage;
153 : #ifdef CONFIG_BLOCK
154 501 : if (!invalidatepage)
155 3 : invalidatepage = block_invalidatepage;
156 : #endif
157 501 : if (invalidatepage)
158 501 : (*invalidatepage)(page, offset, length);
159 501 : }
160 :
161 : /*
162 : * If truncate cannot remove the fs-private metadata from the page, the page
163 : * becomes orphaned. It will be left on the LRU and may even be mapped into
164 : * user pagetables if we're racing with filemap_fault().
165 : *
166 : * We need to bail out if page->mapping is no longer equal to the original
167 : * mapping. This happens a) when the VM reclaimed the page while we waited on
168 : * its lock, b) when a concurrent invalidate_mapping_pages got there first and
169 : * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
170 : */
171 : static void
172 1979 : truncate_cleanup_page(struct address_space *mapping, struct page *page)
173 : {
174 1979 : if (page_mapped(page)) {
175 0 : unsigned int nr = thp_nr_pages(page);
176 0 : unmap_mapping_pages(mapping, page->index, nr, false);
177 : }
178 :
179 1979 : if (page_has_private(page))
180 499 : do_invalidatepage(page, 0, thp_size(page));
181 :
182 : /*
183 : * Some filesystems seem to re-dirty the page even after
184 : * the VM has canceled the dirty bit (eg ext3 journaling).
185 : * Hence dirty accounting check is placed after invalidation.
186 : */
187 1979 : cancel_dirty_page(page);
188 1979 : ClearPageMappedToDisk(page);
189 1979 : }
190 :
191 : /*
192 : * This is for invalidate_mapping_pages(). That function can be called at
193 : * any time, and is not supposed to throw away dirty pages. But pages can
194 : * be marked dirty at any time too, so use remove_mapping which safely
195 : * discards clean, unused pages.
196 : *
197 : * Returns non-zero if the page was successfully invalidated.
198 : */
199 : static int
200 0 : invalidate_complete_page(struct address_space *mapping, struct page *page)
201 : {
202 0 : int ret;
203 :
204 0 : if (page->mapping != mapping)
205 : return 0;
206 :
207 0 : if (page_has_private(page) && !try_to_release_page(page, 0))
208 : return 0;
209 :
210 0 : ret = remove_mapping(mapping, page);
211 :
212 0 : return ret;
213 : }
214 :
215 668 : int truncate_inode_page(struct address_space *mapping, struct page *page)
216 : {
217 668 : VM_BUG_ON_PAGE(PageTail(page), page);
218 :
219 668 : if (page->mapping != mapping)
220 : return -EIO;
221 :
222 668 : truncate_cleanup_page(mapping, page);
223 668 : delete_from_page_cache(page);
224 668 : return 0;
225 : }
226 :
227 : /*
228 : * Used to get rid of pages on hardware memory corruption.
229 : */
230 0 : int generic_error_remove_page(struct address_space *mapping, struct page *page)
231 : {
232 0 : if (!mapping)
233 : return -EINVAL;
234 : /*
235 : * Only punch for normal data pages for now.
236 : * Handling other types like directories would need more auditing.
237 : */
238 0 : if (!S_ISREG(mapping->host->i_mode))
239 : return -EIO;
240 0 : return truncate_inode_page(mapping, page);
241 : }
242 : EXPORT_SYMBOL(generic_error_remove_page);
243 :
244 : /*
245 : * Safely invalidate one page from its pagecache mapping.
246 : * It only drops clean, unused pages. The page must be locked.
247 : *
248 : * Returns 1 if the page is successfully invalidated, otherwise 0.
249 : */
250 0 : int invalidate_inode_page(struct page *page)
251 : {
252 0 : struct address_space *mapping = page_mapping(page);
253 0 : if (!mapping)
254 : return 0;
255 0 : if (PageDirty(page) || PageWriteback(page))
256 0 : return 0;
257 0 : if (page_mapped(page))
258 : return 0;
259 0 : return invalidate_complete_page(mapping, page);
260 : }
261 :
262 : /**
263 : * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets
264 : * @mapping: mapping to truncate
265 : * @lstart: offset from which to truncate
266 : * @lend: offset to which to truncate (inclusive)
267 : *
268 : * Truncate the page cache, removing the pages that are between
269 : * specified offsets (and zeroing out partial pages
270 : * if lstart or lend + 1 is not page aligned).
271 : *
272 : * Truncate takes two passes - the first pass is nonblocking. It will not
273 : * block on page locks and it will not block on writeback. The second pass
274 : * will wait. This is to prevent as much IO as possible in the affected region.
275 : * The first pass will remove most pages, so the search cost of the second pass
276 : * is low.
277 : *
278 : * We pass down the cache-hot hint to the page freeing code. Even if the
279 : * mapping is large, it is probably the case that the final pages are the most
280 : * recently touched, and freeing happens in ascending file offset order.
281 : *
282 : * Note that since ->invalidatepage() accepts range to invalidate
283 : * truncate_inode_pages_range is able to handle cases where lend + 1 is not
284 : * page aligned properly.
285 : */
286 3955 : void truncate_inode_pages_range(struct address_space *mapping,
287 : loff_t lstart, loff_t lend)
288 : {
289 3955 : pgoff_t start; /* inclusive */
290 3955 : pgoff_t end; /* exclusive */
291 3955 : unsigned int partial_start; /* inclusive */
292 3955 : unsigned int partial_end; /* exclusive */
293 3955 : struct pagevec pvec;
294 3955 : pgoff_t indices[PAGEVEC_SIZE];
295 3955 : pgoff_t index;
296 3955 : int i;
297 :
298 3955 : if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
299 3869 : goto out;
300 :
301 : /* Offsets within partial pages */
302 86 : partial_start = lstart & (PAGE_SIZE - 1);
303 86 : partial_end = (lend + 1) & (PAGE_SIZE - 1);
304 :
305 : /*
306 : * 'start' and 'end' always covers the range of pages to be fully
307 : * truncated. Partial pages are covered with 'partial_start' at the
308 : * start of the range and 'partial_end' at the end of the range.
309 : * Note that 'end' is exclusive while 'lend' is inclusive.
310 : */
311 86 : start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
312 86 : if (lend == -1)
313 : /*
314 : * lend == -1 indicates end-of-file so we have to set 'end'
315 : * to the highest possible pgoff_t and since the type is
316 : * unsigned we're using -1.
317 : */
318 : end = -1;
319 : else
320 0 : end = (lend + 1) >> PAGE_SHIFT;
321 :
322 86 : pagevec_init(&pvec);
323 86 : index = start;
324 230 : while (index < end && find_lock_entries(mapping, index, end - 1,
325 : &pvec, indices)) {
326 144 : index = indices[pagevec_count(&pvec) - 1] + 1;
327 144 : truncate_exceptional_pvec_entries(mapping, &pvec, indices);
328 1599 : for (i = 0; i < pagevec_count(&pvec); i++)
329 1311 : truncate_cleanup_page(mapping, pvec.pages[i]);
330 144 : delete_from_page_cache_batch(mapping, &pvec);
331 1599 : for (i = 0; i < pagevec_count(&pvec); i++)
332 1311 : unlock_page(pvec.pages[i]);
333 144 : pagevec_release(&pvec);
334 144 : cond_resched();
335 : }
336 :
337 86 : if (partial_start) {
338 2 : struct page *page = find_lock_page(mapping, start - 1);
339 2 : if (page) {
340 2 : unsigned int top = PAGE_SIZE;
341 2 : if (start > end) {
342 : /* Truncation within a single page */
343 0 : top = partial_end;
344 0 : partial_end = 0;
345 : }
346 2 : wait_on_page_writeback(page);
347 2 : zero_user_segment(page, partial_start, top);
348 2 : cleancache_invalidate_page(mapping, page);
349 2 : if (page_has_private(page))
350 2 : do_invalidatepage(page, partial_start,
351 : top - partial_start);
352 2 : unlock_page(page);
353 2 : put_page(page);
354 : }
355 : }
356 86 : if (partial_end) {
357 0 : struct page *page = find_lock_page(mapping, end);
358 0 : if (page) {
359 0 : wait_on_page_writeback(page);
360 0 : zero_user_segment(page, 0, partial_end);
361 0 : cleancache_invalidate_page(mapping, page);
362 0 : if (page_has_private(page))
363 0 : do_invalidatepage(page, 0,
364 : partial_end);
365 0 : unlock_page(page);
366 0 : put_page(page);
367 : }
368 : }
369 : /*
370 : * If the truncation happened within a single page no pages
371 : * will be released, just zeroed, so we can bail out now.
372 : */
373 86 : if (start >= end)
374 0 : goto out;
375 :
376 : index = start;
377 86 : for ( ; ; ) {
378 86 : cond_resched();
379 86 : if (!find_get_entries(mapping, index, end - 1, &pvec,
380 : indices)) {
381 : /* If all gone from start onwards, we're done */
382 86 : if (index == start)
383 : break;
384 : /* Otherwise restart to make sure all gone */
385 0 : index = start;
386 0 : continue;
387 : }
388 :
389 0 : for (i = 0; i < pagevec_count(&pvec); i++) {
390 0 : struct page *page = pvec.pages[i];
391 :
392 : /* We rely upon deletion not changing page->index */
393 0 : index = indices[i];
394 :
395 0 : if (xa_is_value(page))
396 0 : continue;
397 :
398 0 : lock_page(page);
399 0 : WARN_ON(page_to_index(page) != index);
400 0 : wait_on_page_writeback(page);
401 0 : truncate_inode_page(mapping, page);
402 0 : unlock_page(page);
403 : }
404 0 : truncate_exceptional_pvec_entries(mapping, &pvec, indices);
405 0 : pagevec_release(&pvec);
406 0 : index++;
407 : }
408 :
409 86 : out:
410 3955 : cleancache_invalidate_inode(mapping);
411 3955 : }
412 : EXPORT_SYMBOL(truncate_inode_pages_range);
413 :
414 : /**
415 : * truncate_inode_pages - truncate *all* the pages from an offset
416 : * @mapping: mapping to truncate
417 : * @lstart: offset from which to truncate
418 : *
419 : * Called under (and serialised by) inode->i_mutex.
420 : *
421 : * Note: When this function returns, there can be a page in the process of
422 : * deletion (inside __delete_from_page_cache()) in the specified range. Thus
423 : * mapping->nrpages can be non-zero when this function returns even after
424 : * truncation of the whole mapping.
425 : */
426 3956 : void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
427 : {
428 3 : truncate_inode_pages_range(mapping, lstart, (loff_t)-1);
429 3 : }
430 : EXPORT_SYMBOL(truncate_inode_pages);
431 :
432 : /**
433 : * truncate_inode_pages_final - truncate *all* pages before inode dies
434 : * @mapping: mapping to truncate
435 : *
436 : * Called under (and serialized by) inode->i_mutex.
437 : *
438 : * Filesystems have to use this in the .evict_inode path to inform the
439 : * VM that this is the final truncate and the inode is going away.
440 : */
441 3947 : void truncate_inode_pages_final(struct address_space *mapping)
442 : {
443 3947 : unsigned long nrexceptional;
444 3947 : unsigned long nrpages;
445 :
446 : /*
447 : * Page reclaim can not participate in regular inode lifetime
448 : * management (can't call iput()) and thus can race with the
449 : * inode teardown. Tell it when the address space is exiting,
450 : * so that it does not install eviction information after the
451 : * final truncate has begun.
452 : */
453 3947 : mapping_set_exiting(mapping);
454 :
455 : /*
456 : * When reclaim installs eviction entries, it increases
457 : * nrexceptional first, then decreases nrpages. Make sure we see
458 : * this in the right order or we might miss an entry.
459 : */
460 3948 : nrpages = mapping->nrpages;
461 3948 : smp_rmb();
462 3948 : nrexceptional = mapping->nrexceptional;
463 :
464 3948 : if (nrpages || nrexceptional) {
465 : /*
466 : * As truncation uses a lockless tree lookup, cycle
467 : * the tree lock to make sure any ongoing tree
468 : * modification that does not see AS_EXITING is
469 : * completed before starting the final truncate.
470 : */
471 80 : xa_lock_irq(&mapping->i_pages);
472 80 : xa_unlock_irq(&mapping->i_pages);
473 : }
474 :
475 : /*
476 : * Cleancache needs notification even if there are no pages or shadow
477 : * entries.
478 : */
479 3948 : truncate_inode_pages(mapping, 0);
480 3947 : }
481 : EXPORT_SYMBOL(truncate_inode_pages_final);
482 :
483 0 : static unsigned long __invalidate_mapping_pages(struct address_space *mapping,
484 : pgoff_t start, pgoff_t end, unsigned long *nr_pagevec)
485 : {
486 0 : pgoff_t indices[PAGEVEC_SIZE];
487 0 : struct pagevec pvec;
488 0 : pgoff_t index = start;
489 0 : unsigned long ret;
490 0 : unsigned long count = 0;
491 0 : int i;
492 :
493 0 : pagevec_init(&pvec);
494 0 : while (find_lock_entries(mapping, index, end, &pvec, indices)) {
495 0 : for (i = 0; i < pagevec_count(&pvec); i++) {
496 0 : struct page *page = pvec.pages[i];
497 :
498 : /* We rely upon deletion not changing page->index */
499 0 : index = indices[i];
500 :
501 0 : if (xa_is_value(page)) {
502 0 : invalidate_exceptional_entry(mapping, index,
503 : page);
504 0 : continue;
505 : }
506 0 : index += thp_nr_pages(page) - 1;
507 :
508 0 : ret = invalidate_inode_page(page);
509 0 : unlock_page(page);
510 : /*
511 : * Invalidation is a hint that the page is no longer
512 : * of interest and try to speed up its reclaim.
513 : */
514 0 : if (!ret) {
515 0 : deactivate_file_page(page);
516 : /* It is likely on the pagevec of a remote CPU */
517 0 : if (nr_pagevec)
518 0 : (*nr_pagevec)++;
519 : }
520 0 : count += ret;
521 : }
522 0 : pagevec_remove_exceptionals(&pvec);
523 0 : pagevec_release(&pvec);
524 0 : cond_resched();
525 0 : index++;
526 : }
527 0 : return count;
528 : }
529 :
530 : /**
531 : * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
532 : * @mapping: the address_space which holds the pages to invalidate
533 : * @start: the offset 'from' which to invalidate
534 : * @end: the offset 'to' which to invalidate (inclusive)
535 : *
536 : * This function only removes the unlocked pages, if you want to
537 : * remove all the pages of one inode, you must call truncate_inode_pages.
538 : *
539 : * invalidate_mapping_pages() will not block on IO activity. It will not
540 : * invalidate pages which are dirty, locked, under writeback or mapped into
541 : * pagetables.
542 : *
543 : * Return: the number of the pages that were invalidated
544 : */
545 0 : unsigned long invalidate_mapping_pages(struct address_space *mapping,
546 : pgoff_t start, pgoff_t end)
547 : {
548 0 : return __invalidate_mapping_pages(mapping, start, end, NULL);
549 : }
550 : EXPORT_SYMBOL(invalidate_mapping_pages);
551 :
552 : /**
553 : * invalidate_mapping_pagevec - Invalidate all the unlocked pages of one inode
554 : * @mapping: the address_space which holds the pages to invalidate
555 : * @start: the offset 'from' which to invalidate
556 : * @end: the offset 'to' which to invalidate (inclusive)
557 : * @nr_pagevec: invalidate failed page number for caller
558 : *
559 : * This helper is similar to invalidate_mapping_pages(), except that it accounts
560 : * for pages that are likely on a pagevec and counts them in @nr_pagevec, which
561 : * will be used by the caller.
562 : */
563 0 : void invalidate_mapping_pagevec(struct address_space *mapping,
564 : pgoff_t start, pgoff_t end, unsigned long *nr_pagevec)
565 : {
566 0 : __invalidate_mapping_pages(mapping, start, end, nr_pagevec);
567 0 : }
568 :
569 : /*
570 : * This is like invalidate_complete_page(), except it ignores the page's
571 : * refcount. We do this because invalidate_inode_pages2() needs stronger
572 : * invalidation guarantees, and cannot afford to leave pages behind because
573 : * shrink_page_list() has a temp ref on them, or because they're transiently
574 : * sitting in the lru_cache_add() pagevecs.
575 : */
576 : static int
577 0 : invalidate_complete_page2(struct address_space *mapping, struct page *page)
578 : {
579 0 : unsigned long flags;
580 :
581 0 : if (page->mapping != mapping)
582 : return 0;
583 :
584 0 : if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
585 : return 0;
586 :
587 0 : xa_lock_irqsave(&mapping->i_pages, flags);
588 0 : if (PageDirty(page))
589 0 : goto failed;
590 :
591 0 : BUG_ON(page_has_private(page));
592 0 : __delete_from_page_cache(page, NULL);
593 0 : xa_unlock_irqrestore(&mapping->i_pages, flags);
594 :
595 0 : if (mapping->a_ops->freepage)
596 0 : mapping->a_ops->freepage(page);
597 :
598 0 : put_page(page); /* pagecache ref */
599 0 : return 1;
600 0 : failed:
601 0 : xa_unlock_irqrestore(&mapping->i_pages, flags);
602 0 : return 0;
603 : }
604 :
605 0 : static int do_launder_page(struct address_space *mapping, struct page *page)
606 : {
607 0 : if (!PageDirty(page))
608 : return 0;
609 0 : if (page->mapping != mapping || mapping->a_ops->launder_page == NULL)
610 : return 0;
611 0 : return mapping->a_ops->launder_page(page);
612 : }
613 :
614 : /**
615 : * invalidate_inode_pages2_range - remove range of pages from an address_space
616 : * @mapping: the address_space
617 : * @start: the page offset 'from' which to invalidate
618 : * @end: the page offset 'to' which to invalidate (inclusive)
619 : *
620 : * Any pages which are found to be mapped into pagetables are unmapped prior to
621 : * invalidation.
622 : *
623 : * Return: -EBUSY if any pages could not be invalidated.
624 : */
625 0 : int invalidate_inode_pages2_range(struct address_space *mapping,
626 : pgoff_t start, pgoff_t end)
627 : {
628 0 : pgoff_t indices[PAGEVEC_SIZE];
629 0 : struct pagevec pvec;
630 0 : pgoff_t index;
631 0 : int i;
632 0 : int ret = 0;
633 0 : int ret2 = 0;
634 0 : int did_range_unmap = 0;
635 :
636 0 : if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
637 0 : goto out;
638 :
639 0 : pagevec_init(&pvec);
640 0 : index = start;
641 0 : while (find_get_entries(mapping, index, end, &pvec, indices)) {
642 0 : for (i = 0; i < pagevec_count(&pvec); i++) {
643 0 : struct page *page = pvec.pages[i];
644 :
645 : /* We rely upon deletion not changing page->index */
646 0 : index = indices[i];
647 :
648 0 : if (xa_is_value(page)) {
649 0 : if (!invalidate_exceptional_entry2(mapping,
650 : index, page))
651 : ret = -EBUSY;
652 0 : continue;
653 : }
654 :
655 0 : lock_page(page);
656 0 : WARN_ON(page_to_index(page) != index);
657 0 : if (page->mapping != mapping) {
658 0 : unlock_page(page);
659 0 : continue;
660 : }
661 0 : wait_on_page_writeback(page);
662 0 : if (page_mapped(page)) {
663 0 : if (!did_range_unmap) {
664 : /*
665 : * Zap the rest of the file in one hit.
666 : */
667 0 : unmap_mapping_pages(mapping, index,
668 0 : (1 + end - index), false);
669 0 : did_range_unmap = 1;
670 : } else {
671 : /*
672 : * Just zap this page
673 : */
674 0 : unmap_mapping_pages(mapping, index,
675 : 1, false);
676 : }
677 : }
678 0 : BUG_ON(page_mapped(page));
679 0 : ret2 = do_launder_page(mapping, page);
680 0 : if (ret2 == 0) {
681 0 : if (!invalidate_complete_page2(mapping, page))
682 : ret2 = -EBUSY;
683 : }
684 0 : if (ret2 < 0)
685 : ret = ret2;
686 0 : unlock_page(page);
687 : }
688 0 : pagevec_remove_exceptionals(&pvec);
689 0 : pagevec_release(&pvec);
690 0 : cond_resched();
691 0 : index++;
692 : }
693 : /*
694 : * For DAX we invalidate page tables after invalidating page cache. We
695 : * could invalidate page tables while invalidating each entry however
696 : * that would be expensive. And doing range unmapping before doesn't
697 : * work as we have no cheap way to find whether page cache entry didn't
698 : * get remapped later.
699 : */
700 0 : if (dax_mapping(mapping)) {
701 : unmap_mapping_pages(mapping, start, end - start + 1, false);
702 : }
703 0 : out:
704 0 : cleancache_invalidate_inode(mapping);
705 0 : return ret;
706 : }
707 : EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
708 :
709 : /**
710 : * invalidate_inode_pages2 - remove all pages from an address_space
711 : * @mapping: the address_space
712 : *
713 : * Any pages which are found to be mapped into pagetables are unmapped prior to
714 : * invalidation.
715 : *
716 : * Return: -EBUSY if any pages could not be invalidated.
717 : */
718 0 : int invalidate_inode_pages2(struct address_space *mapping)
719 : {
720 0 : return invalidate_inode_pages2_range(mapping, 0, -1);
721 : }
722 : EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
723 :
724 : /**
725 : * truncate_pagecache - unmap and remove pagecache that has been truncated
726 : * @inode: inode
727 : * @newsize: new file size
728 : *
729 : * inode's new i_size must already be written before truncate_pagecache
730 : * is called.
731 : *
732 : * This function should typically be called before the filesystem
733 : * releases resources associated with the freed range (eg. deallocates
734 : * blocks). This way, pagecache will always stay logically coherent
735 : * with on-disk format, and the filesystem would not have to deal with
736 : * situations such as writepage being called for a page that has already
737 : * had its underlying blocks deallocated.
738 : */
739 5 : void truncate_pagecache(struct inode *inode, loff_t newsize)
740 : {
741 5 : struct address_space *mapping = inode->i_mapping;
742 5 : loff_t holebegin = round_up(newsize, PAGE_SIZE);
743 :
744 : /*
745 : * unmap_mapping_range is called twice, first simply for
746 : * efficiency so that truncate_inode_pages does fewer
747 : * single-page unmaps. However after this first call, and
748 : * before truncate_inode_pages finishes, it is possible for
749 : * private pages to be COWed, which remain after
750 : * truncate_inode_pages finishes, hence the second
751 : * unmap_mapping_range call must be made for correctness.
752 : */
753 5 : unmap_mapping_range(mapping, holebegin, 0, 1);
754 5 : truncate_inode_pages(mapping, newsize);
755 5 : unmap_mapping_range(mapping, holebegin, 0, 1);
756 5 : }
757 : EXPORT_SYMBOL(truncate_pagecache);
758 :
759 : /**
760 : * truncate_setsize - update inode and pagecache for a new file size
761 : * @inode: inode
762 : * @newsize: new file size
763 : *
764 : * truncate_setsize updates i_size and performs pagecache truncation (if
765 : * necessary) to @newsize. It will be typically be called from the filesystem's
766 : * setattr function when ATTR_SIZE is passed in.
767 : *
768 : * Must be called with a lock serializing truncates and writes (generally
769 : * i_mutex but e.g. xfs uses a different lock) and before all filesystem
770 : * specific block truncation has been performed.
771 : */
772 0 : void truncate_setsize(struct inode *inode, loff_t newsize)
773 : {
774 0 : loff_t oldsize = inode->i_size;
775 :
776 0 : i_size_write(inode, newsize);
777 0 : if (newsize > oldsize)
778 0 : pagecache_isize_extended(inode, oldsize, newsize);
779 0 : truncate_pagecache(inode, newsize);
780 0 : }
781 : EXPORT_SYMBOL(truncate_setsize);
782 :
783 : /**
784 : * pagecache_isize_extended - update pagecache after extension of i_size
785 : * @inode: inode for which i_size was extended
786 : * @from: original inode size
787 : * @to: new inode size
788 : *
789 : * Handle extension of inode size either caused by extending truncate or by
790 : * write starting after current i_size. We mark the page straddling current
791 : * i_size RO so that page_mkwrite() is called on the nearest write access to
792 : * the page. This way filesystem can be sure that page_mkwrite() is called on
793 : * the page before user writes to the page via mmap after the i_size has been
794 : * changed.
795 : *
796 : * The function must be called after i_size is updated so that page fault
797 : * coming after we unlock the page will already see the new i_size.
798 : * The function must be called while we still hold i_mutex - this not only
799 : * makes sure i_size is stable but also that userspace cannot observe new
800 : * i_size value before we are prepared to store mmap writes at new inode size.
801 : */
802 0 : void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to)
803 : {
804 0 : int bsize = i_blocksize(inode);
805 0 : loff_t rounded_from;
806 0 : struct page *page;
807 0 : pgoff_t index;
808 :
809 0 : WARN_ON(to > inode->i_size);
810 :
811 0 : if (from >= to || bsize == PAGE_SIZE)
812 : return;
813 : /* Page straddling @from will not have any hole block created? */
814 0 : rounded_from = round_up(from, bsize);
815 0 : if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1)))
816 : return;
817 :
818 0 : index = from >> PAGE_SHIFT;
819 0 : page = find_lock_page(inode->i_mapping, index);
820 : /* Page not cached? Nothing to do */
821 0 : if (!page)
822 : return;
823 : /*
824 : * See clear_page_dirty_for_io() for details why set_page_dirty()
825 : * is needed.
826 : */
827 0 : if (page_mkclean(page))
828 0 : set_page_dirty(page);
829 0 : unlock_page(page);
830 0 : put_page(page);
831 : }
832 : EXPORT_SYMBOL(pagecache_isize_extended);
833 :
834 : /**
835 : * truncate_pagecache_range - unmap and remove pagecache that is hole-punched
836 : * @inode: inode
837 : * @lstart: offset of beginning of hole
838 : * @lend: offset of last byte of hole
839 : *
840 : * This function should typically be called before the filesystem
841 : * releases resources associated with the freed range (eg. deallocates
842 : * blocks). This way, pagecache will always stay logically coherent
843 : * with on-disk format, and the filesystem would not have to deal with
844 : * situations such as writepage being called for a page that has already
845 : * had its underlying blocks deallocated.
846 : */
847 0 : void truncate_pagecache_range(struct inode *inode, loff_t lstart, loff_t lend)
848 : {
849 0 : struct address_space *mapping = inode->i_mapping;
850 0 : loff_t unmap_start = round_up(lstart, PAGE_SIZE);
851 0 : loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1;
852 : /*
853 : * This rounding is currently just for example: unmap_mapping_range
854 : * expands its hole outwards, whereas we want it to contract the hole
855 : * inwards. However, existing callers of truncate_pagecache_range are
856 : * doing their own page rounding first. Note that unmap_mapping_range
857 : * allows holelen 0 for all, and we allow lend -1 for end of file.
858 : */
859 :
860 : /*
861 : * Unlike in truncate_pagecache, unmap_mapping_range is called only
862 : * once (before truncating pagecache), and without "even_cows" flag:
863 : * hole-punching should not remove private COWed pages from the hole.
864 : */
865 0 : if ((u64)unmap_end > (u64)unmap_start)
866 0 : unmap_mapping_range(mapping, unmap_start,
867 0 : 1 + unmap_end - unmap_start, 0);
868 0 : truncate_inode_pages_range(mapping, lstart, lend);
869 0 : }
870 : EXPORT_SYMBOL(truncate_pagecache_range);
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