1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * mm/truncate.c - code for taking down pages from address_spaces |
4 | * |
5 | * Copyright (C) 2002, Linus Torvalds |
6 | * |
7 | * 10Sep2002 Andrew Morton |
8 | * Initial version. |
9 | */ |
10 | |
11 | #include <linux/kernel.h> |
12 | #include <linux/backing-dev.h> |
13 | #include <linux/dax.h> |
14 | #include <linux/gfp.h> |
15 | #include <linux/mm.h> |
16 | #include <linux/swap.h> |
17 | #include <linux/export.h> |
18 | #include <linux/pagemap.h> |
19 | #include <linux/highmem.h> |
20 | #include <linux/pagevec.h> |
21 | #include <linux/task_io_accounting_ops.h> |
22 | #include <linux/shmem_fs.h> |
23 | #include <linux/rmap.h> |
24 | #include "internal.h" |
25 | |
26 | /* |
27 | * Regular page slots are stabilized by the page lock even without the tree |
28 | * itself locked. These unlocked entries need verification under the tree |
29 | * lock. |
30 | */ |
31 | static inline void __clear_shadow_entry(struct address_space *mapping, |
32 | pgoff_t index, void *entry) |
33 | { |
34 | XA_STATE(xas, &mapping->i_pages, index); |
35 | |
36 | xas_set_update(xas: &xas, update: workingset_update_node); |
37 | if (xas_load(&xas) != entry) |
38 | return; |
39 | xas_store(&xas, NULL); |
40 | } |
41 | |
42 | static void clear_shadow_entry(struct address_space *mapping, pgoff_t index, |
43 | void *entry) |
44 | { |
45 | spin_lock(lock: &mapping->host->i_lock); |
46 | xa_lock_irq(&mapping->i_pages); |
47 | __clear_shadow_entry(mapping, index, entry); |
48 | xa_unlock_irq(&mapping->i_pages); |
49 | if (mapping_shrinkable(mapping)) |
50 | inode_add_lru(inode: mapping->host); |
51 | spin_unlock(lock: &mapping->host->i_lock); |
52 | } |
53 | |
54 | /* |
55 | * Unconditionally remove exceptional entries. Usually called from truncate |
56 | * path. Note that the folio_batch may be altered by this function by removing |
57 | * exceptional entries similar to what folio_batch_remove_exceptionals() does. |
58 | */ |
59 | static void truncate_folio_batch_exceptionals(struct address_space *mapping, |
60 | struct folio_batch *fbatch, pgoff_t *indices) |
61 | { |
62 | int i, j; |
63 | bool dax; |
64 | |
65 | /* Handled by shmem itself */ |
66 | if (shmem_mapping(mapping)) |
67 | return; |
68 | |
69 | for (j = 0; j < folio_batch_count(fbatch); j++) |
70 | if (xa_is_value(entry: fbatch->folios[j])) |
71 | break; |
72 | |
73 | if (j == folio_batch_count(fbatch)) |
74 | return; |
75 | |
76 | dax = dax_mapping(mapping); |
77 | if (!dax) { |
78 | spin_lock(lock: &mapping->host->i_lock); |
79 | xa_lock_irq(&mapping->i_pages); |
80 | } |
81 | |
82 | for (i = j; i < folio_batch_count(fbatch); i++) { |
83 | struct folio *folio = fbatch->folios[i]; |
84 | pgoff_t index = indices[i]; |
85 | |
86 | if (!xa_is_value(entry: folio)) { |
87 | fbatch->folios[j++] = folio; |
88 | continue; |
89 | } |
90 | |
91 | if (unlikely(dax)) { |
92 | dax_delete_mapping_entry(mapping, index); |
93 | continue; |
94 | } |
95 | |
96 | __clear_shadow_entry(mapping, index, entry: folio); |
97 | } |
98 | |
99 | if (!dax) { |
100 | xa_unlock_irq(&mapping->i_pages); |
101 | if (mapping_shrinkable(mapping)) |
102 | inode_add_lru(inode: mapping->host); |
103 | spin_unlock(lock: &mapping->host->i_lock); |
104 | } |
105 | fbatch->nr = j; |
106 | } |
107 | |
108 | /* |
109 | * Invalidate exceptional entry if easily possible. This handles exceptional |
110 | * entries for invalidate_inode_pages(). |
111 | */ |
112 | static int invalidate_exceptional_entry(struct address_space *mapping, |
113 | pgoff_t index, void *entry) |
114 | { |
115 | /* Handled by shmem itself, or for DAX we do nothing. */ |
116 | if (shmem_mapping(mapping) || dax_mapping(mapping)) |
117 | return 1; |
118 | clear_shadow_entry(mapping, index, entry); |
119 | return 1; |
120 | } |
121 | |
122 | /* |
123 | * Invalidate exceptional entry if clean. This handles exceptional entries for |
124 | * invalidate_inode_pages2() so for DAX it evicts only clean entries. |
125 | */ |
126 | static int invalidate_exceptional_entry2(struct address_space *mapping, |
127 | pgoff_t index, void *entry) |
128 | { |
129 | /* Handled by shmem itself */ |
130 | if (shmem_mapping(mapping)) |
131 | return 1; |
132 | if (dax_mapping(mapping)) |
133 | return dax_invalidate_mapping_entry_sync(mapping, index); |
134 | clear_shadow_entry(mapping, index, entry); |
135 | return 1; |
136 | } |
137 | |
138 | /** |
139 | * folio_invalidate - Invalidate part or all of a folio. |
140 | * @folio: The folio which is affected. |
141 | * @offset: start of the range to invalidate |
142 | * @length: length of the range to invalidate |
143 | * |
144 | * folio_invalidate() is called when all or part of the folio has become |
145 | * invalidated by a truncate operation. |
146 | * |
147 | * folio_invalidate() does not have to release all buffers, but it must |
148 | * ensure that no dirty buffer is left outside @offset and that no I/O |
149 | * is underway against any of the blocks which are outside the truncation |
150 | * point. Because the caller is about to free (and possibly reuse) those |
151 | * blocks on-disk. |
152 | */ |
153 | void folio_invalidate(struct folio *folio, size_t offset, size_t length) |
154 | { |
155 | const struct address_space_operations *aops = folio->mapping->a_ops; |
156 | |
157 | if (aops->invalidate_folio) |
158 | aops->invalidate_folio(folio, offset, length); |
159 | } |
160 | EXPORT_SYMBOL_GPL(folio_invalidate); |
161 | |
162 | /* |
163 | * If truncate cannot remove the fs-private metadata from the page, the page |
164 | * becomes orphaned. It will be left on the LRU and may even be mapped into |
165 | * user pagetables if we're racing with filemap_fault(). |
166 | * |
167 | * We need to bail out if page->mapping is no longer equal to the original |
168 | * mapping. This happens a) when the VM reclaimed the page while we waited on |
169 | * its lock, b) when a concurrent invalidate_mapping_pages got there first and |
170 | * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. |
171 | */ |
172 | static void truncate_cleanup_folio(struct folio *folio) |
173 | { |
174 | if (folio_mapped(folio)) |
175 | unmap_mapping_folio(folio); |
176 | |
177 | if (folio_has_private(folio)) |
178 | folio_invalidate(folio, 0, folio_size(folio)); |
179 | |
180 | /* |
181 | * Some filesystems seem to re-dirty the page even after |
182 | * the VM has canceled the dirty bit (eg ext3 journaling). |
183 | * Hence dirty accounting check is placed after invalidation. |
184 | */ |
185 | folio_cancel_dirty(folio); |
186 | folio_clear_mappedtodisk(folio); |
187 | } |
188 | |
189 | int truncate_inode_folio(struct address_space *mapping, struct folio *folio) |
190 | { |
191 | if (folio->mapping != mapping) |
192 | return -EIO; |
193 | |
194 | truncate_cleanup_folio(folio); |
195 | filemap_remove_folio(folio); |
196 | return 0; |
197 | } |
198 | |
199 | /* |
200 | * Handle partial folios. The folio may be entirely within the |
201 | * range if a split has raced with us. If not, we zero the part of the |
202 | * folio that's within the [start, end] range, and then split the folio if |
203 | * it's large. split_page_range() will discard pages which now lie beyond |
204 | * i_size, and we rely on the caller to discard pages which lie within a |
205 | * newly created hole. |
206 | * |
207 | * Returns false if splitting failed so the caller can avoid |
208 | * discarding the entire folio which is stubbornly unsplit. |
209 | */ |
210 | bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end) |
211 | { |
212 | loff_t pos = folio_pos(folio); |
213 | unsigned int offset, length; |
214 | |
215 | if (pos < start) |
216 | offset = start - pos; |
217 | else |
218 | offset = 0; |
219 | length = folio_size(folio); |
220 | if (pos + length <= (u64)end) |
221 | length = length - offset; |
222 | else |
223 | length = end + 1 - pos - offset; |
224 | |
225 | folio_wait_writeback(folio); |
226 | if (length == folio_size(folio)) { |
227 | truncate_inode_folio(mapping: folio->mapping, folio); |
228 | return true; |
229 | } |
230 | |
231 | /* |
232 | * We may be zeroing pages we're about to discard, but it avoids |
233 | * doing a complex calculation here, and then doing the zeroing |
234 | * anyway if the page split fails. |
235 | */ |
236 | folio_zero_range(folio, start: offset, length); |
237 | |
238 | if (folio_has_private(folio)) |
239 | folio_invalidate(folio, offset, length); |
240 | if (!folio_test_large(folio)) |
241 | return true; |
242 | if (split_folio(folio) == 0) |
243 | return true; |
244 | if (folio_test_dirty(folio)) |
245 | return false; |
246 | truncate_inode_folio(mapping: folio->mapping, folio); |
247 | return true; |
248 | } |
249 | |
250 | /* |
251 | * Used to get rid of pages on hardware memory corruption. |
252 | */ |
253 | int generic_error_remove_page(struct address_space *mapping, struct page *page) |
254 | { |
255 | VM_BUG_ON_PAGE(PageTail(page), page); |
256 | |
257 | if (!mapping) |
258 | return -EINVAL; |
259 | /* |
260 | * Only punch for normal data pages for now. |
261 | * Handling other types like directories would need more auditing. |
262 | */ |
263 | if (!S_ISREG(mapping->host->i_mode)) |
264 | return -EIO; |
265 | return truncate_inode_folio(mapping, page_folio(page)); |
266 | } |
267 | EXPORT_SYMBOL(generic_error_remove_page); |
268 | |
269 | static long mapping_evict_folio(struct address_space *mapping, |
270 | struct folio *folio) |
271 | { |
272 | if (folio_test_dirty(folio) || folio_test_writeback(folio)) |
273 | return 0; |
274 | /* The refcount will be elevated if any page in the folio is mapped */ |
275 | if (folio_ref_count(folio) > |
276 | folio_nr_pages(folio) + folio_has_private(folio) + 1) |
277 | return 0; |
278 | if (!filemap_release_folio(folio, gfp: 0)) |
279 | return 0; |
280 | |
281 | return remove_mapping(mapping, folio); |
282 | } |
283 | |
284 | /** |
285 | * invalidate_inode_page() - Remove an unused page from the pagecache. |
286 | * @page: The page to remove. |
287 | * |
288 | * Safely invalidate one page from its pagecache mapping. |
289 | * It only drops clean, unused pages. |
290 | * |
291 | * Context: Page must be locked. |
292 | * Return: The number of pages successfully removed. |
293 | */ |
294 | long invalidate_inode_page(struct page *page) |
295 | { |
296 | struct folio *folio = page_folio(page); |
297 | struct address_space *mapping = folio_mapping(folio); |
298 | |
299 | /* The page may have been truncated before it was locked */ |
300 | if (!mapping) |
301 | return 0; |
302 | return mapping_evict_folio(mapping, folio); |
303 | } |
304 | |
305 | /** |
306 | * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets |
307 | * @mapping: mapping to truncate |
308 | * @lstart: offset from which to truncate |
309 | * @lend: offset to which to truncate (inclusive) |
310 | * |
311 | * Truncate the page cache, removing the pages that are between |
312 | * specified offsets (and zeroing out partial pages |
313 | * if lstart or lend + 1 is not page aligned). |
314 | * |
315 | * Truncate takes two passes - the first pass is nonblocking. It will not |
316 | * block on page locks and it will not block on writeback. The second pass |
317 | * will wait. This is to prevent as much IO as possible in the affected region. |
318 | * The first pass will remove most pages, so the search cost of the second pass |
319 | * is low. |
320 | * |
321 | * We pass down the cache-hot hint to the page freeing code. Even if the |
322 | * mapping is large, it is probably the case that the final pages are the most |
323 | * recently touched, and freeing happens in ascending file offset order. |
324 | * |
325 | * Note that since ->invalidate_folio() accepts range to invalidate |
326 | * truncate_inode_pages_range is able to handle cases where lend + 1 is not |
327 | * page aligned properly. |
328 | */ |
329 | void truncate_inode_pages_range(struct address_space *mapping, |
330 | loff_t lstart, loff_t lend) |
331 | { |
332 | pgoff_t start; /* inclusive */ |
333 | pgoff_t end; /* exclusive */ |
334 | struct folio_batch fbatch; |
335 | pgoff_t indices[PAGEVEC_SIZE]; |
336 | pgoff_t index; |
337 | int i; |
338 | struct folio *folio; |
339 | bool same_folio; |
340 | |
341 | if (mapping_empty(mapping)) |
342 | return; |
343 | |
344 | /* |
345 | * 'start' and 'end' always covers the range of pages to be fully |
346 | * truncated. Partial pages are covered with 'partial_start' at the |
347 | * start of the range and 'partial_end' at the end of the range. |
348 | * Note that 'end' is exclusive while 'lend' is inclusive. |
349 | */ |
350 | start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT; |
351 | if (lend == -1) |
352 | /* |
353 | * lend == -1 indicates end-of-file so we have to set 'end' |
354 | * to the highest possible pgoff_t and since the type is |
355 | * unsigned we're using -1. |
356 | */ |
357 | end = -1; |
358 | else |
359 | end = (lend + 1) >> PAGE_SHIFT; |
360 | |
361 | folio_batch_init(fbatch: &fbatch); |
362 | index = start; |
363 | while (index < end && find_lock_entries(mapping, start: &index, end: end - 1, |
364 | fbatch: &fbatch, indices)) { |
365 | truncate_folio_batch_exceptionals(mapping, fbatch: &fbatch, indices); |
366 | for (i = 0; i < folio_batch_count(fbatch: &fbatch); i++) |
367 | truncate_cleanup_folio(folio: fbatch.folios[i]); |
368 | delete_from_page_cache_batch(mapping, fbatch: &fbatch); |
369 | for (i = 0; i < folio_batch_count(fbatch: &fbatch); i++) |
370 | folio_unlock(folio: fbatch.folios[i]); |
371 | folio_batch_release(fbatch: &fbatch); |
372 | cond_resched(); |
373 | } |
374 | |
375 | same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT); |
376 | folio = __filemap_get_folio(mapping, index: lstart >> PAGE_SHIFT, FGP_LOCK, gfp: 0); |
377 | if (!IS_ERR(ptr: folio)) { |
378 | same_folio = lend < folio_pos(folio) + folio_size(folio); |
379 | if (!truncate_inode_partial_folio(folio, start: lstart, end: lend)) { |
380 | start = folio_next_index(folio); |
381 | if (same_folio) |
382 | end = folio->index; |
383 | } |
384 | folio_unlock(folio); |
385 | folio_put(folio); |
386 | folio = NULL; |
387 | } |
388 | |
389 | if (!same_folio) { |
390 | folio = __filemap_get_folio(mapping, index: lend >> PAGE_SHIFT, |
391 | FGP_LOCK, gfp: 0); |
392 | if (!IS_ERR(ptr: folio)) { |
393 | if (!truncate_inode_partial_folio(folio, start: lstart, end: lend)) |
394 | end = folio->index; |
395 | folio_unlock(folio); |
396 | folio_put(folio); |
397 | } |
398 | } |
399 | |
400 | index = start; |
401 | while (index < end) { |
402 | cond_resched(); |
403 | if (!find_get_entries(mapping, start: &index, end: end - 1, fbatch: &fbatch, |
404 | indices)) { |
405 | /* If all gone from start onwards, we're done */ |
406 | if (index == start) |
407 | break; |
408 | /* Otherwise restart to make sure all gone */ |
409 | index = start; |
410 | continue; |
411 | } |
412 | |
413 | for (i = 0; i < folio_batch_count(fbatch: &fbatch); i++) { |
414 | struct folio *folio = fbatch.folios[i]; |
415 | |
416 | /* We rely upon deletion not changing page->index */ |
417 | |
418 | if (xa_is_value(entry: folio)) |
419 | continue; |
420 | |
421 | folio_lock(folio); |
422 | VM_BUG_ON_FOLIO(!folio_contains(folio, indices[i]), folio); |
423 | folio_wait_writeback(folio); |
424 | truncate_inode_folio(mapping, folio); |
425 | folio_unlock(folio); |
426 | } |
427 | truncate_folio_batch_exceptionals(mapping, fbatch: &fbatch, indices); |
428 | folio_batch_release(fbatch: &fbatch); |
429 | } |
430 | } |
431 | EXPORT_SYMBOL(truncate_inode_pages_range); |
432 | |
433 | /** |
434 | * truncate_inode_pages - truncate *all* the pages from an offset |
435 | * @mapping: mapping to truncate |
436 | * @lstart: offset from which to truncate |
437 | * |
438 | * Called under (and serialised by) inode->i_rwsem and |
439 | * mapping->invalidate_lock. |
440 | * |
441 | * Note: When this function returns, there can be a page in the process of |
442 | * deletion (inside __filemap_remove_folio()) in the specified range. Thus |
443 | * mapping->nrpages can be non-zero when this function returns even after |
444 | * truncation of the whole mapping. |
445 | */ |
446 | void truncate_inode_pages(struct address_space *mapping, loff_t lstart) |
447 | { |
448 | truncate_inode_pages_range(mapping, lstart, (loff_t)-1); |
449 | } |
450 | EXPORT_SYMBOL(truncate_inode_pages); |
451 | |
452 | /** |
453 | * truncate_inode_pages_final - truncate *all* pages before inode dies |
454 | * @mapping: mapping to truncate |
455 | * |
456 | * Called under (and serialized by) inode->i_rwsem. |
457 | * |
458 | * Filesystems have to use this in the .evict_inode path to inform the |
459 | * VM that this is the final truncate and the inode is going away. |
460 | */ |
461 | void truncate_inode_pages_final(struct address_space *mapping) |
462 | { |
463 | /* |
464 | * Page reclaim can not participate in regular inode lifetime |
465 | * management (can't call iput()) and thus can race with the |
466 | * inode teardown. Tell it when the address space is exiting, |
467 | * so that it does not install eviction information after the |
468 | * final truncate has begun. |
469 | */ |
470 | mapping_set_exiting(mapping); |
471 | |
472 | if (!mapping_empty(mapping)) { |
473 | /* |
474 | * As truncation uses a lockless tree lookup, cycle |
475 | * the tree lock to make sure any ongoing tree |
476 | * modification that does not see AS_EXITING is |
477 | * completed before starting the final truncate. |
478 | */ |
479 | xa_lock_irq(&mapping->i_pages); |
480 | xa_unlock_irq(&mapping->i_pages); |
481 | } |
482 | |
483 | truncate_inode_pages(mapping, 0); |
484 | } |
485 | EXPORT_SYMBOL(truncate_inode_pages_final); |
486 | |
487 | /** |
488 | * mapping_try_invalidate - Invalidate all the evictable folios of one inode |
489 | * @mapping: the address_space which holds the folios to invalidate |
490 | * @start: the offset 'from' which to invalidate |
491 | * @end: the offset 'to' which to invalidate (inclusive) |
492 | * @nr_failed: How many folio invalidations failed |
493 | * |
494 | * This function is similar to invalidate_mapping_pages(), except that it |
495 | * returns the number of folios which could not be evicted in @nr_failed. |
496 | */ |
497 | unsigned long mapping_try_invalidate(struct address_space *mapping, |
498 | pgoff_t start, pgoff_t end, unsigned long *nr_failed) |
499 | { |
500 | pgoff_t indices[PAGEVEC_SIZE]; |
501 | struct folio_batch fbatch; |
502 | pgoff_t index = start; |
503 | unsigned long ret; |
504 | unsigned long count = 0; |
505 | int i; |
506 | |
507 | folio_batch_init(fbatch: &fbatch); |
508 | while (find_lock_entries(mapping, start: &index, end, fbatch: &fbatch, indices)) { |
509 | for (i = 0; i < folio_batch_count(fbatch: &fbatch); i++) { |
510 | struct folio *folio = fbatch.folios[i]; |
511 | |
512 | /* We rely upon deletion not changing folio->index */ |
513 | |
514 | if (xa_is_value(entry: folio)) { |
515 | count += invalidate_exceptional_entry(mapping, |
516 | index: indices[i], entry: folio); |
517 | continue; |
518 | } |
519 | |
520 | ret = mapping_evict_folio(mapping, folio); |
521 | folio_unlock(folio); |
522 | /* |
523 | * Invalidation is a hint that the folio is no longer |
524 | * of interest and try to speed up its reclaim. |
525 | */ |
526 | if (!ret) { |
527 | deactivate_file_folio(folio); |
528 | /* Likely in the lru cache of a remote CPU */ |
529 | if (nr_failed) |
530 | (*nr_failed)++; |
531 | } |
532 | count += ret; |
533 | } |
534 | folio_batch_remove_exceptionals(fbatch: &fbatch); |
535 | folio_batch_release(fbatch: &fbatch); |
536 | cond_resched(); |
537 | } |
538 | return count; |
539 | } |
540 | |
541 | /** |
542 | * invalidate_mapping_pages - Invalidate all clean, unlocked cache of one inode |
543 | * @mapping: the address_space which holds the cache to invalidate |
544 | * @start: the offset 'from' which to invalidate |
545 | * @end: the offset 'to' which to invalidate (inclusive) |
546 | * |
547 | * This function removes pages that are clean, unmapped and unlocked, |
548 | * as well as shadow entries. It will not block on IO activity. |
549 | * |
550 | * If you want to remove all the pages of one inode, regardless of |
551 | * their use and writeback state, use truncate_inode_pages(). |
552 | * |
553 | * Return: The number of indices that had their contents invalidated |
554 | */ |
555 | unsigned long invalidate_mapping_pages(struct address_space *mapping, |
556 | pgoff_t start, pgoff_t end) |
557 | { |
558 | return mapping_try_invalidate(mapping, start, end, NULL); |
559 | } |
560 | EXPORT_SYMBOL(invalidate_mapping_pages); |
561 | |
562 | /* |
563 | * This is like invalidate_inode_page(), except it ignores the page's |
564 | * refcount. We do this because invalidate_inode_pages2() needs stronger |
565 | * invalidation guarantees, and cannot afford to leave pages behind because |
566 | * shrink_page_list() has a temp ref on them, or because they're transiently |
567 | * sitting in the folio_add_lru() caches. |
568 | */ |
569 | static int invalidate_complete_folio2(struct address_space *mapping, |
570 | struct folio *folio) |
571 | { |
572 | if (folio->mapping != mapping) |
573 | return 0; |
574 | |
575 | if (!filemap_release_folio(folio, GFP_KERNEL)) |
576 | return 0; |
577 | |
578 | spin_lock(lock: &mapping->host->i_lock); |
579 | xa_lock_irq(&mapping->i_pages); |
580 | if (folio_test_dirty(folio)) |
581 | goto failed; |
582 | |
583 | BUG_ON(folio_has_private(folio)); |
584 | __filemap_remove_folio(folio, NULL); |
585 | xa_unlock_irq(&mapping->i_pages); |
586 | if (mapping_shrinkable(mapping)) |
587 | inode_add_lru(inode: mapping->host); |
588 | spin_unlock(lock: &mapping->host->i_lock); |
589 | |
590 | filemap_free_folio(mapping, folio); |
591 | return 1; |
592 | failed: |
593 | xa_unlock_irq(&mapping->i_pages); |
594 | spin_unlock(lock: &mapping->host->i_lock); |
595 | return 0; |
596 | } |
597 | |
598 | static int folio_launder(struct address_space *mapping, struct folio *folio) |
599 | { |
600 | if (!folio_test_dirty(folio)) |
601 | return 0; |
602 | if (folio->mapping != mapping || mapping->a_ops->launder_folio == NULL) |
603 | return 0; |
604 | return mapping->a_ops->launder_folio(folio); |
605 | } |
606 | |
607 | /** |
608 | * invalidate_inode_pages2_range - remove range of pages from an address_space |
609 | * @mapping: the address_space |
610 | * @start: the page offset 'from' which to invalidate |
611 | * @end: the page offset 'to' which to invalidate (inclusive) |
612 | * |
613 | * Any pages which are found to be mapped into pagetables are unmapped prior to |
614 | * invalidation. |
615 | * |
616 | * Return: -EBUSY if any pages could not be invalidated. |
617 | */ |
618 | int invalidate_inode_pages2_range(struct address_space *mapping, |
619 | pgoff_t start, pgoff_t end) |
620 | { |
621 | pgoff_t indices[PAGEVEC_SIZE]; |
622 | struct folio_batch fbatch; |
623 | pgoff_t index; |
624 | int i; |
625 | int ret = 0; |
626 | int ret2 = 0; |
627 | int did_range_unmap = 0; |
628 | |
629 | if (mapping_empty(mapping)) |
630 | return 0; |
631 | |
632 | folio_batch_init(fbatch: &fbatch); |
633 | index = start; |
634 | while (find_get_entries(mapping, start: &index, end, fbatch: &fbatch, indices)) { |
635 | for (i = 0; i < folio_batch_count(fbatch: &fbatch); i++) { |
636 | struct folio *folio = fbatch.folios[i]; |
637 | |
638 | /* We rely upon deletion not changing folio->index */ |
639 | |
640 | if (xa_is_value(entry: folio)) { |
641 | if (!invalidate_exceptional_entry2(mapping, |
642 | index: indices[i], entry: folio)) |
643 | ret = -EBUSY; |
644 | continue; |
645 | } |
646 | |
647 | if (!did_range_unmap && folio_mapped(folio)) { |
648 | /* |
649 | * If folio is mapped, before taking its lock, |
650 | * zap the rest of the file in one hit. |
651 | */ |
652 | unmap_mapping_pages(mapping, start: indices[i], |
653 | nr: (1 + end - indices[i]), even_cows: false); |
654 | did_range_unmap = 1; |
655 | } |
656 | |
657 | folio_lock(folio); |
658 | if (unlikely(folio->mapping != mapping)) { |
659 | folio_unlock(folio); |
660 | continue; |
661 | } |
662 | VM_BUG_ON_FOLIO(!folio_contains(folio, indices[i]), folio); |
663 | folio_wait_writeback(folio); |
664 | |
665 | if (folio_mapped(folio)) |
666 | unmap_mapping_folio(folio); |
667 | BUG_ON(folio_mapped(folio)); |
668 | |
669 | ret2 = folio_launder(mapping, folio); |
670 | if (ret2 == 0) { |
671 | if (!invalidate_complete_folio2(mapping, folio)) |
672 | ret2 = -EBUSY; |
673 | } |
674 | if (ret2 < 0) |
675 | ret = ret2; |
676 | folio_unlock(folio); |
677 | } |
678 | folio_batch_remove_exceptionals(fbatch: &fbatch); |
679 | folio_batch_release(fbatch: &fbatch); |
680 | cond_resched(); |
681 | } |
682 | /* |
683 | * For DAX we invalidate page tables after invalidating page cache. We |
684 | * could invalidate page tables while invalidating each entry however |
685 | * that would be expensive. And doing range unmapping before doesn't |
686 | * work as we have no cheap way to find whether page cache entry didn't |
687 | * get remapped later. |
688 | */ |
689 | if (dax_mapping(mapping)) { |
690 | unmap_mapping_pages(mapping, start, nr: end - start + 1, even_cows: false); |
691 | } |
692 | return ret; |
693 | } |
694 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range); |
695 | |
696 | /** |
697 | * invalidate_inode_pages2 - remove all pages from an address_space |
698 | * @mapping: the address_space |
699 | * |
700 | * Any pages which are found to be mapped into pagetables are unmapped prior to |
701 | * invalidation. |
702 | * |
703 | * Return: -EBUSY if any pages could not be invalidated. |
704 | */ |
705 | int invalidate_inode_pages2(struct address_space *mapping) |
706 | { |
707 | return invalidate_inode_pages2_range(mapping, 0, -1); |
708 | } |
709 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2); |
710 | |
711 | /** |
712 | * truncate_pagecache - unmap and remove pagecache that has been truncated |
713 | * @inode: inode |
714 | * @newsize: new file size |
715 | * |
716 | * inode's new i_size must already be written before truncate_pagecache |
717 | * is called. |
718 | * |
719 | * This function should typically be called before the filesystem |
720 | * releases resources associated with the freed range (eg. deallocates |
721 | * blocks). This way, pagecache will always stay logically coherent |
722 | * with on-disk format, and the filesystem would not have to deal with |
723 | * situations such as writepage being called for a page that has already |
724 | * had its underlying blocks deallocated. |
725 | */ |
726 | void truncate_pagecache(struct inode *inode, loff_t newsize) |
727 | { |
728 | struct address_space *mapping = inode->i_mapping; |
729 | loff_t holebegin = round_up(newsize, PAGE_SIZE); |
730 | |
731 | /* |
732 | * unmap_mapping_range is called twice, first simply for |
733 | * efficiency so that truncate_inode_pages does fewer |
734 | * single-page unmaps. However after this first call, and |
735 | * before truncate_inode_pages finishes, it is possible for |
736 | * private pages to be COWed, which remain after |
737 | * truncate_inode_pages finishes, hence the second |
738 | * unmap_mapping_range call must be made for correctness. |
739 | */ |
740 | unmap_mapping_range(mapping, holebegin, holelen: 0, even_cows: 1); |
741 | truncate_inode_pages(mapping, newsize); |
742 | unmap_mapping_range(mapping, holebegin, holelen: 0, even_cows: 1); |
743 | } |
744 | EXPORT_SYMBOL(truncate_pagecache); |
745 | |
746 | /** |
747 | * truncate_setsize - update inode and pagecache for a new file size |
748 | * @inode: inode |
749 | * @newsize: new file size |
750 | * |
751 | * truncate_setsize updates i_size and performs pagecache truncation (if |
752 | * necessary) to @newsize. It will be typically be called from the filesystem's |
753 | * setattr function when ATTR_SIZE is passed in. |
754 | * |
755 | * Must be called with a lock serializing truncates and writes (generally |
756 | * i_rwsem but e.g. xfs uses a different lock) and before all filesystem |
757 | * specific block truncation has been performed. |
758 | */ |
759 | void truncate_setsize(struct inode *inode, loff_t newsize) |
760 | { |
761 | loff_t oldsize = inode->i_size; |
762 | |
763 | i_size_write(inode, i_size: newsize); |
764 | if (newsize > oldsize) |
765 | pagecache_isize_extended(inode, from: oldsize, to: newsize); |
766 | truncate_pagecache(inode, newsize); |
767 | } |
768 | EXPORT_SYMBOL(truncate_setsize); |
769 | |
770 | /** |
771 | * pagecache_isize_extended - update pagecache after extension of i_size |
772 | * @inode: inode for which i_size was extended |
773 | * @from: original inode size |
774 | * @to: new inode size |
775 | * |
776 | * Handle extension of inode size either caused by extending truncate or by |
777 | * write starting after current i_size. We mark the page straddling current |
778 | * i_size RO so that page_mkwrite() is called on the nearest write access to |
779 | * the page. This way filesystem can be sure that page_mkwrite() is called on |
780 | * the page before user writes to the page via mmap after the i_size has been |
781 | * changed. |
782 | * |
783 | * The function must be called after i_size is updated so that page fault |
784 | * coming after we unlock the page will already see the new i_size. |
785 | * The function must be called while we still hold i_rwsem - this not only |
786 | * makes sure i_size is stable but also that userspace cannot observe new |
787 | * i_size value before we are prepared to store mmap writes at new inode size. |
788 | */ |
789 | void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to) |
790 | { |
791 | int bsize = i_blocksize(node: inode); |
792 | loff_t rounded_from; |
793 | struct page *page; |
794 | pgoff_t index; |
795 | |
796 | WARN_ON(to > inode->i_size); |
797 | |
798 | if (from >= to || bsize == PAGE_SIZE) |
799 | return; |
800 | /* Page straddling @from will not have any hole block created? */ |
801 | rounded_from = round_up(from, bsize); |
802 | if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1))) |
803 | return; |
804 | |
805 | index = from >> PAGE_SHIFT; |
806 | page = find_lock_page(mapping: inode->i_mapping, index); |
807 | /* Page not cached? Nothing to do */ |
808 | if (!page) |
809 | return; |
810 | /* |
811 | * See clear_page_dirty_for_io() for details why set_page_dirty() |
812 | * is needed. |
813 | */ |
814 | if (page_mkclean(page)) |
815 | set_page_dirty(page); |
816 | unlock_page(page); |
817 | put_page(page); |
818 | } |
819 | EXPORT_SYMBOL(pagecache_isize_extended); |
820 | |
821 | /** |
822 | * truncate_pagecache_range - unmap and remove pagecache that is hole-punched |
823 | * @inode: inode |
824 | * @lstart: offset of beginning of hole |
825 | * @lend: offset of last byte of hole |
826 | * |
827 | * This function should typically be called before the filesystem |
828 | * releases resources associated with the freed range (eg. deallocates |
829 | * blocks). This way, pagecache will always stay logically coherent |
830 | * with on-disk format, and the filesystem would not have to deal with |
831 | * situations such as writepage being called for a page that has already |
832 | * had its underlying blocks deallocated. |
833 | */ |
834 | void truncate_pagecache_range(struct inode *inode, loff_t lstart, loff_t lend) |
835 | { |
836 | struct address_space *mapping = inode->i_mapping; |
837 | loff_t unmap_start = round_up(lstart, PAGE_SIZE); |
838 | loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1; |
839 | /* |
840 | * This rounding is currently just for example: unmap_mapping_range |
841 | * expands its hole outwards, whereas we want it to contract the hole |
842 | * inwards. However, existing callers of truncate_pagecache_range are |
843 | * doing their own page rounding first. Note that unmap_mapping_range |
844 | * allows holelen 0 for all, and we allow lend -1 for end of file. |
845 | */ |
846 | |
847 | /* |
848 | * Unlike in truncate_pagecache, unmap_mapping_range is called only |
849 | * once (before truncating pagecache), and without "even_cows" flag: |
850 | * hole-punching should not remove private COWed pages from the hole. |
851 | */ |
852 | if ((u64)unmap_end > (u64)unmap_start) |
853 | unmap_mapping_range(mapping, holebegin: unmap_start, |
854 | holelen: 1 + unmap_end - unmap_start, even_cows: 0); |
855 | truncate_inode_pages_range(mapping, lstart, lend); |
856 | } |
857 | EXPORT_SYMBOL(truncate_pagecache_range); |
858 | |