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