blob: befdc6f575d268da706ecfe9eb9a047a8f5fdc48
1 | /* |
2 | * mm/truncate.c - code for taking down pages from address_spaces |
3 | * |
4 | * Copyright (C) 2002, Linus Torvalds |
5 | * |
6 | * 10Sep2002 Andrew Morton |
7 | * Initial version. |
8 | */ |
9 | |
10 | #include <linux/kernel.h> |
11 | #include <linux/backing-dev.h> |
12 | #include <linux/dax.h> |
13 | #include <linux/gfp.h> |
14 | #include <linux/mm.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, |
22 | do_invalidatepage */ |
23 | #include <linux/cleancache.h> |
24 | #include <linux/rmap.h> |
25 | #include "internal.h" |
26 | |
27 | static void clear_exceptional_entry(struct address_space *mapping, |
28 | pgoff_t index, void *entry) |
29 | { |
30 | struct radix_tree_node *node; |
31 | void **slot; |
32 | |
33 | /* Handled by shmem itself */ |
34 | if (shmem_mapping(mapping)) |
35 | return; |
36 | |
37 | if (dax_mapping(mapping)) { |
38 | dax_delete_mapping_entry(mapping, index); |
39 | return; |
40 | } |
41 | spin_lock_irq(&mapping->tree_lock); |
42 | /* |
43 | * Regular page slots are stabilized by the page lock even |
44 | * without the tree itself locked. These unlocked entries |
45 | * need verification under the tree lock. |
46 | */ |
47 | if (!__radix_tree_lookup(&mapping->page_tree, index, &node, |
48 | &slot)) |
49 | goto unlock; |
50 | if (*slot != entry) |
51 | goto unlock; |
52 | radix_tree_replace_slot(slot, NULL); |
53 | mapping->nrexceptional--; |
54 | if (!node) |
55 | goto unlock; |
56 | workingset_node_shadows_dec(node); |
57 | /* |
58 | * Don't track node without shadow entries. |
59 | * |
60 | * Avoid acquiring the list_lru lock if already untracked. |
61 | * The list_empty() test is safe as node->private_list is |
62 | * protected by mapping->tree_lock. |
63 | */ |
64 | if (!workingset_node_shadows(node) && |
65 | !list_empty(&node->private_list)) |
66 | list_lru_del(&workingset_shadow_nodes, |
67 | &node->private_list); |
68 | __radix_tree_delete_node(&mapping->page_tree, node); |
69 | unlock: |
70 | spin_unlock_irq(&mapping->tree_lock); |
71 | } |
72 | |
73 | /** |
74 | * do_invalidatepage - invalidate part or all of a page |
75 | * @page: the page which is affected |
76 | * @offset: start of the range to invalidate |
77 | * @length: length of the range to invalidate |
78 | * |
79 | * do_invalidatepage() is called when all or part of the page has become |
80 | * invalidated by a truncate operation. |
81 | * |
82 | * do_invalidatepage() does not have to release all buffers, but it must |
83 | * ensure that no dirty buffer is left outside @offset and that no I/O |
84 | * is underway against any of the blocks which are outside the truncation |
85 | * point. Because the caller is about to free (and possibly reuse) those |
86 | * blocks on-disk. |
87 | */ |
88 | void do_invalidatepage(struct page *page, unsigned int offset, |
89 | unsigned int length) |
90 | { |
91 | void (*invalidatepage)(struct page *, unsigned int, unsigned int); |
92 | |
93 | invalidatepage = page->mapping->a_ops->invalidatepage; |
94 | #ifdef CONFIG_BLOCK |
95 | if (!invalidatepage) |
96 | invalidatepage = block_invalidatepage; |
97 | #endif |
98 | if (invalidatepage) |
99 | (*invalidatepage)(page, offset, length); |
100 | } |
101 | |
102 | /* |
103 | * If truncate cannot remove the fs-private metadata from the page, the page |
104 | * becomes orphaned. It will be left on the LRU and may even be mapped into |
105 | * user pagetables if we're racing with filemap_fault(). |
106 | * |
107 | * We need to bale out if page->mapping is no longer equal to the original |
108 | * mapping. This happens a) when the VM reclaimed the page while we waited on |
109 | * its lock, b) when a concurrent invalidate_mapping_pages got there first and |
110 | * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. |
111 | */ |
112 | static int |
113 | truncate_complete_page(struct address_space *mapping, struct page *page) |
114 | { |
115 | if (page->mapping != mapping) |
116 | return -EIO; |
117 | |
118 | if (page_has_private(page)) |
119 | do_invalidatepage(page, 0, PAGE_SIZE); |
120 | |
121 | /* |
122 | * Some filesystems seem to re-dirty the page even after |
123 | * the VM has canceled the dirty bit (eg ext3 journaling). |
124 | * Hence dirty accounting check is placed after invalidation. |
125 | */ |
126 | cancel_dirty_page(page); |
127 | ClearPageMappedToDisk(page); |
128 | delete_from_page_cache(page); |
129 | return 0; |
130 | } |
131 | |
132 | /* |
133 | * This is for invalidate_mapping_pages(). That function can be called at |
134 | * any time, and is not supposed to throw away dirty pages. But pages can |
135 | * be marked dirty at any time too, so use remove_mapping which safely |
136 | * discards clean, unused pages. |
137 | * |
138 | * Returns non-zero if the page was successfully invalidated. |
139 | */ |
140 | static int |
141 | invalidate_complete_page(struct address_space *mapping, struct page *page) |
142 | { |
143 | int ret; |
144 | |
145 | if (page->mapping != mapping) |
146 | return 0; |
147 | |
148 | if (page_has_private(page) && !try_to_release_page(page, 0)) |
149 | return 0; |
150 | |
151 | ret = remove_mapping(mapping, page); |
152 | |
153 | return ret; |
154 | } |
155 | |
156 | int truncate_inode_page(struct address_space *mapping, struct page *page) |
157 | { |
158 | loff_t holelen; |
159 | VM_BUG_ON_PAGE(PageTail(page), page); |
160 | |
161 | holelen = PageTransHuge(page) ? HPAGE_PMD_SIZE : PAGE_SIZE; |
162 | if (page_mapped(page)) { |
163 | unmap_mapping_range(mapping, |
164 | (loff_t)page->index << PAGE_SHIFT, |
165 | holelen, 0); |
166 | } |
167 | return truncate_complete_page(mapping, page); |
168 | } |
169 | |
170 | /* |
171 | * Used to get rid of pages on hardware memory corruption. |
172 | */ |
173 | int generic_error_remove_page(struct address_space *mapping, struct page *page) |
174 | { |
175 | if (!mapping) |
176 | return -EINVAL; |
177 | /* |
178 | * Only punch for normal data pages for now. |
179 | * Handling other types like directories would need more auditing. |
180 | */ |
181 | if (!S_ISREG(mapping->host->i_mode)) |
182 | return -EIO; |
183 | return truncate_inode_page(mapping, page); |
184 | } |
185 | EXPORT_SYMBOL(generic_error_remove_page); |
186 | |
187 | /* |
188 | * Safely invalidate one page from its pagecache mapping. |
189 | * It only drops clean, unused pages. The page must be locked. |
190 | * |
191 | * Returns 1 if the page is successfully invalidated, otherwise 0. |
192 | */ |
193 | int invalidate_inode_page(struct page *page) |
194 | { |
195 | struct address_space *mapping = page_mapping(page); |
196 | if (!mapping) |
197 | return 0; |
198 | if (PageDirty(page) || PageWriteback(page)) |
199 | return 0; |
200 | if (page_mapped(page)) |
201 | return 0; |
202 | return invalidate_complete_page(mapping, page); |
203 | } |
204 | |
205 | /** |
206 | * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets |
207 | * @mapping: mapping to truncate |
208 | * @lstart: offset from which to truncate |
209 | * @lend: offset to which to truncate (inclusive) |
210 | * |
211 | * Truncate the page cache, removing the pages that are between |
212 | * specified offsets (and zeroing out partial pages |
213 | * if lstart or lend + 1 is not page aligned). |
214 | * |
215 | * Truncate takes two passes - the first pass is nonblocking. It will not |
216 | * block on page locks and it will not block on writeback. The second pass |
217 | * will wait. This is to prevent as much IO as possible in the affected region. |
218 | * The first pass will remove most pages, so the search cost of the second pass |
219 | * is low. |
220 | * |
221 | * We pass down the cache-hot hint to the page freeing code. Even if the |
222 | * mapping is large, it is probably the case that the final pages are the most |
223 | * recently touched, and freeing happens in ascending file offset order. |
224 | * |
225 | * Note that since ->invalidatepage() accepts range to invalidate |
226 | * truncate_inode_pages_range is able to handle cases where lend + 1 is not |
227 | * page aligned properly. |
228 | */ |
229 | void truncate_inode_pages_range(struct address_space *mapping, |
230 | loff_t lstart, loff_t lend) |
231 | { |
232 | pgoff_t start; /* inclusive */ |
233 | pgoff_t end; /* exclusive */ |
234 | unsigned int partial_start; /* inclusive */ |
235 | unsigned int partial_end; /* exclusive */ |
236 | struct pagevec pvec; |
237 | pgoff_t indices[PAGEVEC_SIZE]; |
238 | pgoff_t index; |
239 | int i; |
240 | |
241 | cleancache_invalidate_inode(mapping); |
242 | if (mapping->nrpages == 0 && mapping->nrexceptional == 0) |
243 | return; |
244 | |
245 | /* Offsets within partial pages */ |
246 | partial_start = lstart & (PAGE_SIZE - 1); |
247 | partial_end = (lend + 1) & (PAGE_SIZE - 1); |
248 | |
249 | /* |
250 | * 'start' and 'end' always covers the range of pages to be fully |
251 | * truncated. Partial pages are covered with 'partial_start' at the |
252 | * start of the range and 'partial_end' at the end of the range. |
253 | * Note that 'end' is exclusive while 'lend' is inclusive. |
254 | */ |
255 | start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT; |
256 | if (lend == -1) |
257 | /* |
258 | * lend == -1 indicates end-of-file so we have to set 'end' |
259 | * to the highest possible pgoff_t and since the type is |
260 | * unsigned we're using -1. |
261 | */ |
262 | end = -1; |
263 | else |
264 | end = (lend + 1) >> PAGE_SHIFT; |
265 | |
266 | pagevec_init(&pvec, 0); |
267 | index = start; |
268 | while (index < end && pagevec_lookup_entries(&pvec, mapping, index, |
269 | min(end - index, (pgoff_t)PAGEVEC_SIZE), |
270 | indices)) { |
271 | for (i = 0; i < pagevec_count(&pvec); i++) { |
272 | struct page *page = pvec.pages[i]; |
273 | |
274 | /* We rely upon deletion not changing page->index */ |
275 | index = indices[i]; |
276 | if (index >= end) |
277 | break; |
278 | |
279 | if (radix_tree_exceptional_entry(page)) { |
280 | clear_exceptional_entry(mapping, index, page); |
281 | continue; |
282 | } |
283 | |
284 | if (!trylock_page(page)) |
285 | continue; |
286 | WARN_ON(page_to_index(page) != index); |
287 | if (PageWriteback(page)) { |
288 | unlock_page(page); |
289 | continue; |
290 | } |
291 | truncate_inode_page(mapping, page); |
292 | unlock_page(page); |
293 | } |
294 | pagevec_remove_exceptionals(&pvec); |
295 | pagevec_release(&pvec); |
296 | cond_resched(); |
297 | index++; |
298 | } |
299 | |
300 | if (partial_start) { |
301 | struct page *page = find_lock_page(mapping, start - 1); |
302 | if (page) { |
303 | unsigned int top = PAGE_SIZE; |
304 | if (start > end) { |
305 | /* Truncation within a single page */ |
306 | top = partial_end; |
307 | partial_end = 0; |
308 | } |
309 | wait_on_page_writeback(page); |
310 | zero_user_segment(page, partial_start, top); |
311 | cleancache_invalidate_page(mapping, page); |
312 | if (page_has_private(page)) |
313 | do_invalidatepage(page, partial_start, |
314 | top - partial_start); |
315 | unlock_page(page); |
316 | put_page(page); |
317 | } |
318 | } |
319 | if (partial_end) { |
320 | struct page *page = find_lock_page(mapping, end); |
321 | if (page) { |
322 | wait_on_page_writeback(page); |
323 | zero_user_segment(page, 0, partial_end); |
324 | cleancache_invalidate_page(mapping, page); |
325 | if (page_has_private(page)) |
326 | do_invalidatepage(page, 0, |
327 | partial_end); |
328 | unlock_page(page); |
329 | put_page(page); |
330 | } |
331 | } |
332 | /* |
333 | * If the truncation happened within a single page no pages |
334 | * will be released, just zeroed, so we can bail out now. |
335 | */ |
336 | if (start >= end) |
337 | return; |
338 | |
339 | index = start; |
340 | for ( ; ; ) { |
341 | cond_resched(); |
342 | if (!pagevec_lookup_entries(&pvec, mapping, index, |
343 | min(end - index, (pgoff_t)PAGEVEC_SIZE), indices)) { |
344 | /* If all gone from start onwards, we're done */ |
345 | if (index == start) |
346 | break; |
347 | /* Otherwise restart to make sure all gone */ |
348 | index = start; |
349 | continue; |
350 | } |
351 | if (index == start && indices[0] >= end) { |
352 | /* All gone out of hole to be punched, we're done */ |
353 | pagevec_remove_exceptionals(&pvec); |
354 | pagevec_release(&pvec); |
355 | break; |
356 | } |
357 | for (i = 0; i < pagevec_count(&pvec); i++) { |
358 | struct page *page = pvec.pages[i]; |
359 | |
360 | /* We rely upon deletion not changing page->index */ |
361 | index = indices[i]; |
362 | if (index >= end) { |
363 | /* Restart punch to make sure all gone */ |
364 | index = start - 1; |
365 | break; |
366 | } |
367 | |
368 | if (radix_tree_exceptional_entry(page)) { |
369 | clear_exceptional_entry(mapping, index, page); |
370 | continue; |
371 | } |
372 | |
373 | lock_page(page); |
374 | WARN_ON(page_to_index(page) != index); |
375 | wait_on_page_writeback(page); |
376 | truncate_inode_page(mapping, page); |
377 | unlock_page(page); |
378 | } |
379 | pagevec_remove_exceptionals(&pvec); |
380 | pagevec_release(&pvec); |
381 | index++; |
382 | } |
383 | cleancache_invalidate_inode(mapping); |
384 | } |
385 | EXPORT_SYMBOL(truncate_inode_pages_range); |
386 | |
387 | /** |
388 | * truncate_inode_pages - truncate *all* the pages from an offset |
389 | * @mapping: mapping to truncate |
390 | * @lstart: offset from which to truncate |
391 | * |
392 | * Called under (and serialised by) inode->i_mutex. |
393 | * |
394 | * Note: When this function returns, there can be a page in the process of |
395 | * deletion (inside __delete_from_page_cache()) in the specified range. Thus |
396 | * mapping->nrpages can be non-zero when this function returns even after |
397 | * truncation of the whole mapping. |
398 | */ |
399 | void truncate_inode_pages(struct address_space *mapping, loff_t lstart) |
400 | { |
401 | truncate_inode_pages_range(mapping, lstart, (loff_t)-1); |
402 | } |
403 | EXPORT_SYMBOL(truncate_inode_pages); |
404 | |
405 | /** |
406 | * truncate_inode_pages_final - truncate *all* pages before inode dies |
407 | * @mapping: mapping to truncate |
408 | * |
409 | * Called under (and serialized by) inode->i_mutex. |
410 | * |
411 | * Filesystems have to use this in the .evict_inode path to inform the |
412 | * VM that this is the final truncate and the inode is going away. |
413 | */ |
414 | void truncate_inode_pages_final(struct address_space *mapping) |
415 | { |
416 | unsigned long nrexceptional; |
417 | unsigned long nrpages; |
418 | |
419 | /* |
420 | * Page reclaim can not participate in regular inode lifetime |
421 | * management (can't call iput()) and thus can race with the |
422 | * inode teardown. Tell it when the address space is exiting, |
423 | * so that it does not install eviction information after the |
424 | * final truncate has begun. |
425 | */ |
426 | mapping_set_exiting(mapping); |
427 | |
428 | /* |
429 | * When reclaim installs eviction entries, it increases |
430 | * nrexceptional first, then decreases nrpages. Make sure we see |
431 | * this in the right order or we might miss an entry. |
432 | */ |
433 | nrpages = mapping->nrpages; |
434 | smp_rmb(); |
435 | nrexceptional = mapping->nrexceptional; |
436 | |
437 | if (nrpages || nrexceptional) { |
438 | /* |
439 | * As truncation uses a lockless tree lookup, cycle |
440 | * the tree lock to make sure any ongoing tree |
441 | * modification that does not see AS_EXITING is |
442 | * completed before starting the final truncate. |
443 | */ |
444 | spin_lock_irq(&mapping->tree_lock); |
445 | spin_unlock_irq(&mapping->tree_lock); |
446 | } |
447 | |
448 | /* |
449 | * Cleancache needs notification even if there are no pages or shadow |
450 | * entries. |
451 | */ |
452 | truncate_inode_pages(mapping, 0); |
453 | } |
454 | EXPORT_SYMBOL(truncate_inode_pages_final); |
455 | |
456 | /** |
457 | * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode |
458 | * @mapping: the address_space which holds the pages to invalidate |
459 | * @start: the offset 'from' which to invalidate |
460 | * @end: the offset 'to' which to invalidate (inclusive) |
461 | * |
462 | * This function only removes the unlocked pages, if you want to |
463 | * remove all the pages of one inode, you must call truncate_inode_pages. |
464 | * |
465 | * invalidate_mapping_pages() will not block on IO activity. It will not |
466 | * invalidate pages which are dirty, locked, under writeback or mapped into |
467 | * pagetables. |
468 | */ |
469 | unsigned long invalidate_mapping_pages(struct address_space *mapping, |
470 | pgoff_t start, pgoff_t end) |
471 | { |
472 | pgoff_t indices[PAGEVEC_SIZE]; |
473 | struct pagevec pvec; |
474 | pgoff_t index = start; |
475 | unsigned long ret; |
476 | unsigned long count = 0; |
477 | int i; |
478 | |
479 | pagevec_init(&pvec, 0); |
480 | while (index <= end && pagevec_lookup_entries(&pvec, mapping, index, |
481 | min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1, |
482 | indices)) { |
483 | for (i = 0; i < pagevec_count(&pvec); i++) { |
484 | struct page *page = pvec.pages[i]; |
485 | |
486 | /* We rely upon deletion not changing page->index */ |
487 | index = indices[i]; |
488 | if (index > end) |
489 | break; |
490 | |
491 | if (radix_tree_exceptional_entry(page)) { |
492 | clear_exceptional_entry(mapping, index, page); |
493 | continue; |
494 | } |
495 | |
496 | if (!trylock_page(page)) |
497 | continue; |
498 | |
499 | WARN_ON(page_to_index(page) != index); |
500 | |
501 | /* Middle of THP: skip */ |
502 | if (PageTransTail(page)) { |
503 | unlock_page(page); |
504 | continue; |
505 | } else if (PageTransHuge(page)) { |
506 | index += HPAGE_PMD_NR - 1; |
507 | i += HPAGE_PMD_NR - 1; |
508 | /* 'end' is in the middle of THP */ |
509 | if (index == round_down(end, HPAGE_PMD_NR)) |
510 | continue; |
511 | } |
512 | |
513 | ret = invalidate_inode_page(page); |
514 | unlock_page(page); |
515 | /* |
516 | * Invalidation is a hint that the page is no longer |
517 | * of interest and try to speed up its reclaim. |
518 | */ |
519 | if (!ret) |
520 | deactivate_file_page(page); |
521 | count += ret; |
522 | } |
523 | pagevec_remove_exceptionals(&pvec); |
524 | pagevec_release(&pvec); |
525 | cond_resched(); |
526 | index++; |
527 | } |
528 | return count; |
529 | } |
530 | EXPORT_SYMBOL(invalidate_mapping_pages); |
531 | |
532 | /* |
533 | * This is like invalidate_complete_page(), except it ignores the page's |
534 | * refcount. We do this because invalidate_inode_pages2() needs stronger |
535 | * invalidation guarantees, and cannot afford to leave pages behind because |
536 | * shrink_page_list() has a temp ref on them, or because they're transiently |
537 | * sitting in the lru_cache_add() pagevecs. |
538 | */ |
539 | static int |
540 | invalidate_complete_page2(struct address_space *mapping, struct page *page) |
541 | { |
542 | unsigned long flags; |
543 | |
544 | if (page->mapping != mapping) |
545 | return 0; |
546 | |
547 | if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) |
548 | return 0; |
549 | |
550 | spin_lock_irqsave(&mapping->tree_lock, flags); |
551 | if (PageDirty(page)) |
552 | goto failed; |
553 | |
554 | BUG_ON(page_has_private(page)); |
555 | __delete_from_page_cache(page, NULL); |
556 | spin_unlock_irqrestore(&mapping->tree_lock, flags); |
557 | |
558 | if (mapping->a_ops->freepage) |
559 | mapping->a_ops->freepage(page); |
560 | |
561 | put_page(page); /* pagecache ref */ |
562 | return 1; |
563 | failed: |
564 | spin_unlock_irqrestore(&mapping->tree_lock, flags); |
565 | return 0; |
566 | } |
567 | |
568 | static int do_launder_page(struct address_space *mapping, struct page *page) |
569 | { |
570 | if (!PageDirty(page)) |
571 | return 0; |
572 | if (page->mapping != mapping || mapping->a_ops->launder_page == NULL) |
573 | return 0; |
574 | return mapping->a_ops->launder_page(page); |
575 | } |
576 | |
577 | /** |
578 | * invalidate_inode_pages2_range - remove range of pages from an address_space |
579 | * @mapping: the address_space |
580 | * @start: the page offset 'from' which to invalidate |
581 | * @end: the page offset 'to' which to invalidate (inclusive) |
582 | * |
583 | * Any pages which are found to be mapped into pagetables are unmapped prior to |
584 | * invalidation. |
585 | * |
586 | * Returns -EBUSY if any pages could not be invalidated. |
587 | */ |
588 | int invalidate_inode_pages2_range(struct address_space *mapping, |
589 | pgoff_t start, pgoff_t end) |
590 | { |
591 | pgoff_t indices[PAGEVEC_SIZE]; |
592 | struct pagevec pvec; |
593 | pgoff_t index; |
594 | int i; |
595 | int ret = 0; |
596 | int ret2 = 0; |
597 | int did_range_unmap = 0; |
598 | |
599 | cleancache_invalidate_inode(mapping); |
600 | pagevec_init(&pvec, 0); |
601 | index = start; |
602 | while (index <= end && pagevec_lookup_entries(&pvec, mapping, index, |
603 | min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1, |
604 | indices)) { |
605 | for (i = 0; i < pagevec_count(&pvec); i++) { |
606 | struct page *page = pvec.pages[i]; |
607 | |
608 | /* We rely upon deletion not changing page->index */ |
609 | index = indices[i]; |
610 | if (index > end) |
611 | break; |
612 | |
613 | if (radix_tree_exceptional_entry(page)) { |
614 | clear_exceptional_entry(mapping, index, page); |
615 | continue; |
616 | } |
617 | |
618 | lock_page(page); |
619 | WARN_ON(page_to_index(page) != index); |
620 | if (page->mapping != mapping) { |
621 | unlock_page(page); |
622 | continue; |
623 | } |
624 | wait_on_page_writeback(page); |
625 | if (page_mapped(page)) { |
626 | if (!did_range_unmap) { |
627 | /* |
628 | * Zap the rest of the file in one hit. |
629 | */ |
630 | unmap_mapping_range(mapping, |
631 | (loff_t)index << PAGE_SHIFT, |
632 | (loff_t)(1 + end - index) |
633 | << PAGE_SHIFT, |
634 | 0); |
635 | did_range_unmap = 1; |
636 | } else { |
637 | /* |
638 | * Just zap this page |
639 | */ |
640 | unmap_mapping_range(mapping, |
641 | (loff_t)index << PAGE_SHIFT, |
642 | PAGE_SIZE, 0); |
643 | } |
644 | } |
645 | BUG_ON(page_mapped(page)); |
646 | ret2 = do_launder_page(mapping, page); |
647 | if (ret2 == 0) { |
648 | if (!invalidate_complete_page2(mapping, page)) |
649 | ret2 = -EBUSY; |
650 | } |
651 | if (ret2 < 0) |
652 | ret = ret2; |
653 | unlock_page(page); |
654 | } |
655 | pagevec_remove_exceptionals(&pvec); |
656 | pagevec_release(&pvec); |
657 | cond_resched(); |
658 | index++; |
659 | } |
660 | cleancache_invalidate_inode(mapping); |
661 | return ret; |
662 | } |
663 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range); |
664 | |
665 | /** |
666 | * invalidate_inode_pages2 - remove all pages from an address_space |
667 | * @mapping: the address_space |
668 | * |
669 | * Any pages which are found to be mapped into pagetables are unmapped prior to |
670 | * invalidation. |
671 | * |
672 | * Returns -EBUSY if any pages could not be invalidated. |
673 | */ |
674 | int invalidate_inode_pages2(struct address_space *mapping) |
675 | { |
676 | return invalidate_inode_pages2_range(mapping, 0, -1); |
677 | } |
678 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2); |
679 | |
680 | /** |
681 | * truncate_pagecache - unmap and remove pagecache that has been truncated |
682 | * @inode: inode |
683 | * @newsize: new file size |
684 | * |
685 | * inode's new i_size must already be written before truncate_pagecache |
686 | * is called. |
687 | * |
688 | * This function should typically be called before the filesystem |
689 | * releases resources associated with the freed range (eg. deallocates |
690 | * blocks). This way, pagecache will always stay logically coherent |
691 | * with on-disk format, and the filesystem would not have to deal with |
692 | * situations such as writepage being called for a page that has already |
693 | * had its underlying blocks deallocated. |
694 | */ |
695 | void truncate_pagecache(struct inode *inode, loff_t newsize) |
696 | { |
697 | struct address_space *mapping = inode->i_mapping; |
698 | loff_t holebegin = round_up(newsize, PAGE_SIZE); |
699 | |
700 | /* |
701 | * unmap_mapping_range is called twice, first simply for |
702 | * efficiency so that truncate_inode_pages does fewer |
703 | * single-page unmaps. However after this first call, and |
704 | * before truncate_inode_pages finishes, it is possible for |
705 | * private pages to be COWed, which remain after |
706 | * truncate_inode_pages finishes, hence the second |
707 | * unmap_mapping_range call must be made for correctness. |
708 | */ |
709 | unmap_mapping_range(mapping, holebegin, 0, 1); |
710 | truncate_inode_pages(mapping, newsize); |
711 | unmap_mapping_range(mapping, holebegin, 0, 1); |
712 | } |
713 | EXPORT_SYMBOL(truncate_pagecache); |
714 | |
715 | /** |
716 | * truncate_setsize - update inode and pagecache for a new file size |
717 | * @inode: inode |
718 | * @newsize: new file size |
719 | * |
720 | * truncate_setsize updates i_size and performs pagecache truncation (if |
721 | * necessary) to @newsize. It will be typically be called from the filesystem's |
722 | * setattr function when ATTR_SIZE is passed in. |
723 | * |
724 | * Must be called with a lock serializing truncates and writes (generally |
725 | * i_mutex but e.g. xfs uses a different lock) and before all filesystem |
726 | * specific block truncation has been performed. |
727 | */ |
728 | void truncate_setsize(struct inode *inode, loff_t newsize) |
729 | { |
730 | loff_t oldsize = inode->i_size; |
731 | |
732 | i_size_write(inode, newsize); |
733 | if (newsize > oldsize) |
734 | pagecache_isize_extended(inode, oldsize, newsize); |
735 | truncate_pagecache(inode, newsize); |
736 | } |
737 | EXPORT_SYMBOL(truncate_setsize); |
738 | |
739 | /** |
740 | * pagecache_isize_extended - update pagecache after extension of i_size |
741 | * @inode: inode for which i_size was extended |
742 | * @from: original inode size |
743 | * @to: new inode size |
744 | * |
745 | * Handle extension of inode size either caused by extending truncate or by |
746 | * write starting after current i_size. We mark the page straddling current |
747 | * i_size RO so that page_mkwrite() is called on the nearest write access to |
748 | * the page. This way filesystem can be sure that page_mkwrite() is called on |
749 | * the page before user writes to the page via mmap after the i_size has been |
750 | * changed. |
751 | * |
752 | * The function must be called after i_size is updated so that page fault |
753 | * coming after we unlock the page will already see the new i_size. |
754 | * The function must be called while we still hold i_mutex - this not only |
755 | * makes sure i_size is stable but also that userspace cannot observe new |
756 | * i_size value before we are prepared to store mmap writes at new inode size. |
757 | */ |
758 | void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to) |
759 | { |
760 | int bsize = i_blocksize(inode); |
761 | loff_t rounded_from; |
762 | struct page *page; |
763 | pgoff_t index; |
764 | |
765 | WARN_ON(to > inode->i_size); |
766 | |
767 | if (from >= to || bsize == PAGE_SIZE) |
768 | return; |
769 | /* Page straddling @from will not have any hole block created? */ |
770 | rounded_from = round_up(from, bsize); |
771 | if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1))) |
772 | return; |
773 | |
774 | index = from >> PAGE_SHIFT; |
775 | page = find_lock_page(inode->i_mapping, index); |
776 | /* Page not cached? Nothing to do */ |
777 | if (!page) |
778 | return; |
779 | /* |
780 | * See clear_page_dirty_for_io() for details why set_page_dirty() |
781 | * is needed. |
782 | */ |
783 | if (page_mkclean(page)) |
784 | set_page_dirty(page); |
785 | unlock_page(page); |
786 | put_page(page); |
787 | } |
788 | EXPORT_SYMBOL(pagecache_isize_extended); |
789 | |
790 | /** |
791 | * truncate_pagecache_range - unmap and remove pagecache that is hole-punched |
792 | * @inode: inode |
793 | * @lstart: offset of beginning of hole |
794 | * @lend: offset of last byte of hole |
795 | * |
796 | * This function should typically be called before the filesystem |
797 | * releases resources associated with the freed range (eg. deallocates |
798 | * blocks). This way, pagecache will always stay logically coherent |
799 | * with on-disk format, and the filesystem would not have to deal with |
800 | * situations such as writepage being called for a page that has already |
801 | * had its underlying blocks deallocated. |
802 | */ |
803 | void truncate_pagecache_range(struct inode *inode, loff_t lstart, loff_t lend) |
804 | { |
805 | struct address_space *mapping = inode->i_mapping; |
806 | loff_t unmap_start = round_up(lstart, PAGE_SIZE); |
807 | loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1; |
808 | /* |
809 | * This rounding is currently just for example: unmap_mapping_range |
810 | * expands its hole outwards, whereas we want it to contract the hole |
811 | * inwards. However, existing callers of truncate_pagecache_range are |
812 | * doing their own page rounding first. Note that unmap_mapping_range |
813 | * allows holelen 0 for all, and we allow lend -1 for end of file. |
814 | */ |
815 | |
816 | /* |
817 | * Unlike in truncate_pagecache, unmap_mapping_range is called only |
818 | * once (before truncating pagecache), and without "even_cows" flag: |
819 | * hole-punching should not remove private COWed pages from the hole. |
820 | */ |
821 | if ((u64)unmap_end > (u64)unmap_start) |
822 | unmap_mapping_range(mapping, unmap_start, |
823 | 1 + unmap_end - unmap_start, 0); |
824 | truncate_inode_pages_range(mapping, lstart, lend); |
825 | } |
826 | EXPORT_SYMBOL(truncate_pagecache_range); |
827 |