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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * mm/truncate.c - code for taking down pages from address_spaces | |
3 | * | |
4 | * Copyright (C) 2002, Linus Torvalds | |
5 | * | |
e1f8e874 | 6 | * 10Sep2002 Andrew Morton |
1da177e4 LT |
7 | * Initial version. |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
4af3c9cc | 11 | #include <linux/backing-dev.h> |
5a0e3ad6 | 12 | #include <linux/gfp.h> |
1da177e4 | 13 | #include <linux/mm.h> |
0fd0e6b0 | 14 | #include <linux/swap.h> |
1da177e4 LT |
15 | #include <linux/module.h> |
16 | #include <linux/pagemap.h> | |
01f2705d | 17 | #include <linux/highmem.h> |
1da177e4 | 18 | #include <linux/pagevec.h> |
e08748ce | 19 | #include <linux/task_io_accounting_ops.h> |
1da177e4 | 20 | #include <linux/buffer_head.h> /* grr. try_to_release_page, |
aaa4059b | 21 | do_invalidatepage */ |
c515e1fd | 22 | #include <linux/cleancache.h> |
ba470de4 | 23 | #include "internal.h" |
1da177e4 LT |
24 | |
25 | ||
cf9a2ae8 | 26 | /** |
28bc44d7 | 27 | * do_invalidatepage - invalidate part or all of a page |
cf9a2ae8 DH |
28 | * @page: the page which is affected |
29 | * @offset: the index of the truncation point | |
30 | * | |
31 | * do_invalidatepage() is called when all or part of the page has become | |
32 | * invalidated by a truncate operation. | |
33 | * | |
34 | * do_invalidatepage() does not have to release all buffers, but it must | |
35 | * ensure that no dirty buffer is left outside @offset and that no I/O | |
36 | * is underway against any of the blocks which are outside the truncation | |
37 | * point. Because the caller is about to free (and possibly reuse) those | |
38 | * blocks on-disk. | |
39 | */ | |
40 | void do_invalidatepage(struct page *page, unsigned long offset) | |
41 | { | |
42 | void (*invalidatepage)(struct page *, unsigned long); | |
43 | invalidatepage = page->mapping->a_ops->invalidatepage; | |
9361401e | 44 | #ifdef CONFIG_BLOCK |
cf9a2ae8 DH |
45 | if (!invalidatepage) |
46 | invalidatepage = block_invalidatepage; | |
9361401e | 47 | #endif |
cf9a2ae8 DH |
48 | if (invalidatepage) |
49 | (*invalidatepage)(page, offset); | |
50 | } | |
51 | ||
1da177e4 LT |
52 | static inline void truncate_partial_page(struct page *page, unsigned partial) |
53 | { | |
eebd2aa3 | 54 | zero_user_segment(page, partial, PAGE_CACHE_SIZE); |
c515e1fd | 55 | cleancache_flush_page(page->mapping, page); |
266cf658 | 56 | if (page_has_private(page)) |
1da177e4 LT |
57 | do_invalidatepage(page, partial); |
58 | } | |
59 | ||
ecdfc978 LT |
60 | /* |
61 | * This cancels just the dirty bit on the kernel page itself, it | |
62 | * does NOT actually remove dirty bits on any mmap's that may be | |
63 | * around. It also leaves the page tagged dirty, so any sync | |
64 | * activity will still find it on the dirty lists, and in particular, | |
65 | * clear_page_dirty_for_io() will still look at the dirty bits in | |
66 | * the VM. | |
67 | * | |
68 | * Doing this should *normally* only ever be done when a page | |
69 | * is truncated, and is not actually mapped anywhere at all. However, | |
70 | * fs/buffer.c does this when it notices that somebody has cleaned | |
71 | * out all the buffers on a page without actually doing it through | |
72 | * the VM. Can you say "ext3 is horribly ugly"? Tought you could. | |
73 | */ | |
fba2591b LT |
74 | void cancel_dirty_page(struct page *page, unsigned int account_size) |
75 | { | |
8368e328 LT |
76 | if (TestClearPageDirty(page)) { |
77 | struct address_space *mapping = page->mapping; | |
78 | if (mapping && mapping_cap_account_dirty(mapping)) { | |
79 | dec_zone_page_state(page, NR_FILE_DIRTY); | |
c9e51e41 PZ |
80 | dec_bdi_stat(mapping->backing_dev_info, |
81 | BDI_RECLAIMABLE); | |
8368e328 LT |
82 | if (account_size) |
83 | task_io_account_cancelled_write(account_size); | |
84 | } | |
3e67c098 | 85 | } |
fba2591b | 86 | } |
8368e328 | 87 | EXPORT_SYMBOL(cancel_dirty_page); |
fba2591b | 88 | |
1da177e4 LT |
89 | /* |
90 | * If truncate cannot remove the fs-private metadata from the page, the page | |
62e1c553 | 91 | * becomes orphaned. It will be left on the LRU and may even be mapped into |
54cb8821 | 92 | * user pagetables if we're racing with filemap_fault(). |
1da177e4 LT |
93 | * |
94 | * We need to bale out if page->mapping is no longer equal to the original | |
95 | * mapping. This happens a) when the VM reclaimed the page while we waited on | |
fc0ecff6 | 96 | * its lock, b) when a concurrent invalidate_mapping_pages got there first and |
1da177e4 LT |
97 | * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. |
98 | */ | |
750b4987 | 99 | static int |
1da177e4 LT |
100 | truncate_complete_page(struct address_space *mapping, struct page *page) |
101 | { | |
102 | if (page->mapping != mapping) | |
750b4987 | 103 | return -EIO; |
1da177e4 | 104 | |
266cf658 | 105 | if (page_has_private(page)) |
1da177e4 LT |
106 | do_invalidatepage(page, 0); |
107 | ||
a2b34564 BS |
108 | cancel_dirty_page(page, PAGE_CACHE_SIZE); |
109 | ||
ba470de4 | 110 | clear_page_mlock(page); |
1da177e4 | 111 | ClearPageMappedToDisk(page); |
5adc7b51 | 112 | delete_from_page_cache(page); |
750b4987 | 113 | return 0; |
1da177e4 LT |
114 | } |
115 | ||
116 | /* | |
fc0ecff6 | 117 | * This is for invalidate_mapping_pages(). That function can be called at |
1da177e4 | 118 | * any time, and is not supposed to throw away dirty pages. But pages can |
0fd0e6b0 NP |
119 | * be marked dirty at any time too, so use remove_mapping which safely |
120 | * discards clean, unused pages. | |
1da177e4 LT |
121 | * |
122 | * Returns non-zero if the page was successfully invalidated. | |
123 | */ | |
124 | static int | |
125 | invalidate_complete_page(struct address_space *mapping, struct page *page) | |
126 | { | |
0fd0e6b0 NP |
127 | int ret; |
128 | ||
1da177e4 LT |
129 | if (page->mapping != mapping) |
130 | return 0; | |
131 | ||
266cf658 | 132 | if (page_has_private(page) && !try_to_release_page(page, 0)) |
1da177e4 LT |
133 | return 0; |
134 | ||
ba470de4 | 135 | clear_page_mlock(page); |
0fd0e6b0 | 136 | ret = remove_mapping(mapping, page); |
0fd0e6b0 NP |
137 | |
138 | return ret; | |
1da177e4 LT |
139 | } |
140 | ||
750b4987 NP |
141 | int truncate_inode_page(struct address_space *mapping, struct page *page) |
142 | { | |
143 | if (page_mapped(page)) { | |
144 | unmap_mapping_range(mapping, | |
145 | (loff_t)page->index << PAGE_CACHE_SHIFT, | |
146 | PAGE_CACHE_SIZE, 0); | |
147 | } | |
148 | return truncate_complete_page(mapping, page); | |
149 | } | |
150 | ||
25718736 AK |
151 | /* |
152 | * Used to get rid of pages on hardware memory corruption. | |
153 | */ | |
154 | int generic_error_remove_page(struct address_space *mapping, struct page *page) | |
155 | { | |
156 | if (!mapping) | |
157 | return -EINVAL; | |
158 | /* | |
159 | * Only punch for normal data pages for now. | |
160 | * Handling other types like directories would need more auditing. | |
161 | */ | |
162 | if (!S_ISREG(mapping->host->i_mode)) | |
163 | return -EIO; | |
164 | return truncate_inode_page(mapping, page); | |
165 | } | |
166 | EXPORT_SYMBOL(generic_error_remove_page); | |
167 | ||
83f78668 WF |
168 | /* |
169 | * Safely invalidate one page from its pagecache mapping. | |
170 | * It only drops clean, unused pages. The page must be locked. | |
171 | * | |
172 | * Returns 1 if the page is successfully invalidated, otherwise 0. | |
173 | */ | |
174 | int invalidate_inode_page(struct page *page) | |
175 | { | |
176 | struct address_space *mapping = page_mapping(page); | |
177 | if (!mapping) | |
178 | return 0; | |
179 | if (PageDirty(page) || PageWriteback(page)) | |
180 | return 0; | |
181 | if (page_mapped(page)) | |
182 | return 0; | |
183 | return invalidate_complete_page(mapping, page); | |
184 | } | |
185 | ||
1da177e4 | 186 | /** |
0643245f | 187 | * truncate_inode_pages - truncate range of pages specified by start & end byte offsets |
1da177e4 LT |
188 | * @mapping: mapping to truncate |
189 | * @lstart: offset from which to truncate | |
d7339071 | 190 | * @lend: offset to which to truncate |
1da177e4 | 191 | * |
d7339071 HR |
192 | * Truncate the page cache, removing the pages that are between |
193 | * specified offsets (and zeroing out partial page | |
194 | * (if lstart is not page aligned)). | |
1da177e4 LT |
195 | * |
196 | * Truncate takes two passes - the first pass is nonblocking. It will not | |
197 | * block on page locks and it will not block on writeback. The second pass | |
198 | * will wait. This is to prevent as much IO as possible in the affected region. | |
199 | * The first pass will remove most pages, so the search cost of the second pass | |
200 | * is low. | |
201 | * | |
202 | * When looking at page->index outside the page lock we need to be careful to | |
203 | * copy it into a local to avoid races (it could change at any time). | |
204 | * | |
205 | * We pass down the cache-hot hint to the page freeing code. Even if the | |
206 | * mapping is large, it is probably the case that the final pages are the most | |
207 | * recently touched, and freeing happens in ascending file offset order. | |
1da177e4 | 208 | */ |
d7339071 HR |
209 | void truncate_inode_pages_range(struct address_space *mapping, |
210 | loff_t lstart, loff_t lend) | |
1da177e4 LT |
211 | { |
212 | const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; | |
d7339071 | 213 | pgoff_t end; |
1da177e4 LT |
214 | const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1); |
215 | struct pagevec pvec; | |
216 | pgoff_t next; | |
217 | int i; | |
218 | ||
c515e1fd | 219 | cleancache_flush_inode(mapping); |
1da177e4 LT |
220 | if (mapping->nrpages == 0) |
221 | return; | |
222 | ||
d7339071 HR |
223 | BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1)); |
224 | end = (lend >> PAGE_CACHE_SHIFT); | |
225 | ||
1da177e4 LT |
226 | pagevec_init(&pvec, 0); |
227 | next = start; | |
d7339071 HR |
228 | while (next <= end && |
229 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
e5598f8b | 230 | mem_cgroup_uncharge_start(); |
1da177e4 LT |
231 | for (i = 0; i < pagevec_count(&pvec); i++) { |
232 | struct page *page = pvec.pages[i]; | |
233 | pgoff_t page_index = page->index; | |
234 | ||
d7339071 HR |
235 | if (page_index > end) { |
236 | next = page_index; | |
237 | break; | |
238 | } | |
239 | ||
1da177e4 LT |
240 | if (page_index > next) |
241 | next = page_index; | |
242 | next++; | |
529ae9aa | 243 | if (!trylock_page(page)) |
1da177e4 LT |
244 | continue; |
245 | if (PageWriteback(page)) { | |
246 | unlock_page(page); | |
247 | continue; | |
248 | } | |
750b4987 | 249 | truncate_inode_page(mapping, page); |
1da177e4 LT |
250 | unlock_page(page); |
251 | } | |
252 | pagevec_release(&pvec); | |
e5598f8b | 253 | mem_cgroup_uncharge_end(); |
1da177e4 LT |
254 | cond_resched(); |
255 | } | |
256 | ||
257 | if (partial) { | |
258 | struct page *page = find_lock_page(mapping, start - 1); | |
259 | if (page) { | |
260 | wait_on_page_writeback(page); | |
261 | truncate_partial_page(page, partial); | |
262 | unlock_page(page); | |
263 | page_cache_release(page); | |
264 | } | |
265 | } | |
266 | ||
267 | next = start; | |
268 | for ( ; ; ) { | |
269 | cond_resched(); | |
270 | if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
271 | if (next == start) | |
272 | break; | |
273 | next = start; | |
274 | continue; | |
275 | } | |
d7339071 HR |
276 | if (pvec.pages[0]->index > end) { |
277 | pagevec_release(&pvec); | |
278 | break; | |
279 | } | |
569b846d | 280 | mem_cgroup_uncharge_start(); |
1da177e4 LT |
281 | for (i = 0; i < pagevec_count(&pvec); i++) { |
282 | struct page *page = pvec.pages[i]; | |
283 | ||
d7339071 HR |
284 | if (page->index > end) |
285 | break; | |
1da177e4 LT |
286 | lock_page(page); |
287 | wait_on_page_writeback(page); | |
750b4987 | 288 | truncate_inode_page(mapping, page); |
1da177e4 LT |
289 | if (page->index > next) |
290 | next = page->index; | |
291 | next++; | |
1da177e4 LT |
292 | unlock_page(page); |
293 | } | |
294 | pagevec_release(&pvec); | |
569b846d | 295 | mem_cgroup_uncharge_end(); |
1da177e4 | 296 | } |
c515e1fd | 297 | cleancache_flush_inode(mapping); |
1da177e4 | 298 | } |
d7339071 | 299 | EXPORT_SYMBOL(truncate_inode_pages_range); |
1da177e4 | 300 | |
d7339071 HR |
301 | /** |
302 | * truncate_inode_pages - truncate *all* the pages from an offset | |
303 | * @mapping: mapping to truncate | |
304 | * @lstart: offset from which to truncate | |
305 | * | |
1b1dcc1b | 306 | * Called under (and serialised by) inode->i_mutex. |
08142579 JK |
307 | * |
308 | * Note: When this function returns, there can be a page in the process of | |
309 | * deletion (inside __delete_from_page_cache()) in the specified range. Thus | |
310 | * mapping->nrpages can be non-zero when this function returns even after | |
311 | * truncation of the whole mapping. | |
d7339071 HR |
312 | */ |
313 | void truncate_inode_pages(struct address_space *mapping, loff_t lstart) | |
314 | { | |
315 | truncate_inode_pages_range(mapping, lstart, (loff_t)-1); | |
316 | } | |
1da177e4 LT |
317 | EXPORT_SYMBOL(truncate_inode_pages); |
318 | ||
28697355 MW |
319 | /** |
320 | * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode | |
321 | * @mapping: the address_space which holds the pages to invalidate | |
322 | * @start: the offset 'from' which to invalidate | |
323 | * @end: the offset 'to' which to invalidate (inclusive) | |
324 | * | |
325 | * This function only removes the unlocked pages, if you want to | |
326 | * remove all the pages of one inode, you must call truncate_inode_pages. | |
327 | * | |
328 | * invalidate_mapping_pages() will not block on IO activity. It will not | |
329 | * invalidate pages which are dirty, locked, under writeback or mapped into | |
330 | * pagetables. | |
331 | */ | |
332 | unsigned long invalidate_mapping_pages(struct address_space *mapping, | |
31560180 | 333 | pgoff_t start, pgoff_t end) |
1da177e4 LT |
334 | { |
335 | struct pagevec pvec; | |
336 | pgoff_t next = start; | |
31560180 MK |
337 | unsigned long ret; |
338 | unsigned long count = 0; | |
1da177e4 LT |
339 | int i; |
340 | ||
341 | pagevec_init(&pvec, 0); | |
342 | while (next <= end && | |
343 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
569b846d | 344 | mem_cgroup_uncharge_start(); |
1da177e4 LT |
345 | for (i = 0; i < pagevec_count(&pvec); i++) { |
346 | struct page *page = pvec.pages[i]; | |
e0f23603 N |
347 | pgoff_t index; |
348 | int lock_failed; | |
1da177e4 | 349 | |
529ae9aa | 350 | lock_failed = !trylock_page(page); |
e0f23603 N |
351 | |
352 | /* | |
353 | * We really shouldn't be looking at the ->index of an | |
354 | * unlocked page. But we're not allowed to lock these | |
355 | * pages. So we rely upon nobody altering the ->index | |
356 | * of this (pinned-by-us) page. | |
357 | */ | |
358 | index = page->index; | |
359 | if (index > next) | |
360 | next = index; | |
1da177e4 | 361 | next++; |
e0f23603 N |
362 | if (lock_failed) |
363 | continue; | |
364 | ||
31560180 | 365 | ret = invalidate_inode_page(page); |
1da177e4 | 366 | unlock_page(page); |
31560180 MK |
367 | /* |
368 | * Invalidation is a hint that the page is no longer | |
369 | * of interest and try to speed up its reclaim. | |
370 | */ | |
371 | if (!ret) | |
372 | deactivate_page(page); | |
373 | count += ret; | |
1da177e4 LT |
374 | if (next > end) |
375 | break; | |
376 | } | |
377 | pagevec_release(&pvec); | |
569b846d | 378 | mem_cgroup_uncharge_end(); |
28697355 | 379 | cond_resched(); |
1da177e4 | 380 | } |
31560180 | 381 | return count; |
1da177e4 | 382 | } |
54bc4855 | 383 | EXPORT_SYMBOL(invalidate_mapping_pages); |
1da177e4 | 384 | |
bd4c8ce4 AM |
385 | /* |
386 | * This is like invalidate_complete_page(), except it ignores the page's | |
387 | * refcount. We do this because invalidate_inode_pages2() needs stronger | |
388 | * invalidation guarantees, and cannot afford to leave pages behind because | |
2706a1b8 AB |
389 | * shrink_page_list() has a temp ref on them, or because they're transiently |
390 | * sitting in the lru_cache_add() pagevecs. | |
bd4c8ce4 AM |
391 | */ |
392 | static int | |
393 | invalidate_complete_page2(struct address_space *mapping, struct page *page) | |
394 | { | |
395 | if (page->mapping != mapping) | |
396 | return 0; | |
397 | ||
266cf658 | 398 | if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) |
bd4c8ce4 AM |
399 | return 0; |
400 | ||
19fd6231 | 401 | spin_lock_irq(&mapping->tree_lock); |
bd4c8ce4 AM |
402 | if (PageDirty(page)) |
403 | goto failed; | |
404 | ||
ba470de4 | 405 | clear_page_mlock(page); |
266cf658 | 406 | BUG_ON(page_has_private(page)); |
e64a782f | 407 | __delete_from_page_cache(page); |
19fd6231 | 408 | spin_unlock_irq(&mapping->tree_lock); |
e767e056 | 409 | mem_cgroup_uncharge_cache_page(page); |
6072d13c LT |
410 | |
411 | if (mapping->a_ops->freepage) | |
412 | mapping->a_ops->freepage(page); | |
413 | ||
bd4c8ce4 AM |
414 | page_cache_release(page); /* pagecache ref */ |
415 | return 1; | |
416 | failed: | |
19fd6231 | 417 | spin_unlock_irq(&mapping->tree_lock); |
bd4c8ce4 AM |
418 | return 0; |
419 | } | |
420 | ||
e3db7691 TM |
421 | static int do_launder_page(struct address_space *mapping, struct page *page) |
422 | { | |
423 | if (!PageDirty(page)) | |
424 | return 0; | |
425 | if (page->mapping != mapping || mapping->a_ops->launder_page == NULL) | |
426 | return 0; | |
427 | return mapping->a_ops->launder_page(page); | |
428 | } | |
429 | ||
1da177e4 LT |
430 | /** |
431 | * invalidate_inode_pages2_range - remove range of pages from an address_space | |
67be2dd1 | 432 | * @mapping: the address_space |
1da177e4 LT |
433 | * @start: the page offset 'from' which to invalidate |
434 | * @end: the page offset 'to' which to invalidate (inclusive) | |
435 | * | |
436 | * Any pages which are found to be mapped into pagetables are unmapped prior to | |
437 | * invalidation. | |
438 | * | |
6ccfa806 | 439 | * Returns -EBUSY if any pages could not be invalidated. |
1da177e4 LT |
440 | */ |
441 | int invalidate_inode_pages2_range(struct address_space *mapping, | |
442 | pgoff_t start, pgoff_t end) | |
443 | { | |
444 | struct pagevec pvec; | |
445 | pgoff_t next; | |
446 | int i; | |
447 | int ret = 0; | |
0dd1334f | 448 | int ret2 = 0; |
1da177e4 LT |
449 | int did_range_unmap = 0; |
450 | int wrapped = 0; | |
451 | ||
c515e1fd | 452 | cleancache_flush_inode(mapping); |
1da177e4 LT |
453 | pagevec_init(&pvec, 0); |
454 | next = start; | |
7b965e08 | 455 | while (next <= end && !wrapped && |
1da177e4 LT |
456 | pagevec_lookup(&pvec, mapping, next, |
457 | min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) { | |
569b846d | 458 | mem_cgroup_uncharge_start(); |
7b965e08 | 459 | for (i = 0; i < pagevec_count(&pvec); i++) { |
1da177e4 LT |
460 | struct page *page = pvec.pages[i]; |
461 | pgoff_t page_index; | |
1da177e4 LT |
462 | |
463 | lock_page(page); | |
464 | if (page->mapping != mapping) { | |
465 | unlock_page(page); | |
466 | continue; | |
467 | } | |
468 | page_index = page->index; | |
469 | next = page_index + 1; | |
470 | if (next == 0) | |
471 | wrapped = 1; | |
472 | if (page_index > end) { | |
473 | unlock_page(page); | |
474 | break; | |
475 | } | |
476 | wait_on_page_writeback(page); | |
d00806b1 | 477 | if (page_mapped(page)) { |
1da177e4 LT |
478 | if (!did_range_unmap) { |
479 | /* | |
480 | * Zap the rest of the file in one hit. | |
481 | */ | |
482 | unmap_mapping_range(mapping, | |
479ef592 OD |
483 | (loff_t)page_index<<PAGE_CACHE_SHIFT, |
484 | (loff_t)(end - page_index + 1) | |
1da177e4 LT |
485 | << PAGE_CACHE_SHIFT, |
486 | 0); | |
487 | did_range_unmap = 1; | |
488 | } else { | |
489 | /* | |
490 | * Just zap this page | |
491 | */ | |
492 | unmap_mapping_range(mapping, | |
479ef592 | 493 | (loff_t)page_index<<PAGE_CACHE_SHIFT, |
1da177e4 LT |
494 | PAGE_CACHE_SIZE, 0); |
495 | } | |
496 | } | |
d00806b1 | 497 | BUG_ON(page_mapped(page)); |
0dd1334f HH |
498 | ret2 = do_launder_page(mapping, page); |
499 | if (ret2 == 0) { | |
500 | if (!invalidate_complete_page2(mapping, page)) | |
6ccfa806 | 501 | ret2 = -EBUSY; |
0dd1334f HH |
502 | } |
503 | if (ret2 < 0) | |
504 | ret = ret2; | |
1da177e4 LT |
505 | unlock_page(page); |
506 | } | |
507 | pagevec_release(&pvec); | |
569b846d | 508 | mem_cgroup_uncharge_end(); |
1da177e4 LT |
509 | cond_resched(); |
510 | } | |
c515e1fd | 511 | cleancache_flush_inode(mapping); |
1da177e4 LT |
512 | return ret; |
513 | } | |
514 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range); | |
515 | ||
516 | /** | |
517 | * invalidate_inode_pages2 - remove all pages from an address_space | |
67be2dd1 | 518 | * @mapping: the address_space |
1da177e4 LT |
519 | * |
520 | * Any pages which are found to be mapped into pagetables are unmapped prior to | |
521 | * invalidation. | |
522 | * | |
e9de25dd | 523 | * Returns -EBUSY if any pages could not be invalidated. |
1da177e4 LT |
524 | */ |
525 | int invalidate_inode_pages2(struct address_space *mapping) | |
526 | { | |
527 | return invalidate_inode_pages2_range(mapping, 0, -1); | |
528 | } | |
529 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2); | |
25d9e2d1 | 530 | |
531 | /** | |
532 | * truncate_pagecache - unmap and remove pagecache that has been truncated | |
533 | * @inode: inode | |
534 | * @old: old file offset | |
535 | * @new: new file offset | |
536 | * | |
537 | * inode's new i_size must already be written before truncate_pagecache | |
538 | * is called. | |
539 | * | |
540 | * This function should typically be called before the filesystem | |
541 | * releases resources associated with the freed range (eg. deallocates | |
542 | * blocks). This way, pagecache will always stay logically coherent | |
543 | * with on-disk format, and the filesystem would not have to deal with | |
544 | * situations such as writepage being called for a page that has already | |
545 | * had its underlying blocks deallocated. | |
546 | */ | |
547 | void truncate_pagecache(struct inode *inode, loff_t old, loff_t new) | |
548 | { | |
cedabed4 OH |
549 | struct address_space *mapping = inode->i_mapping; |
550 | ||
551 | /* | |
552 | * unmap_mapping_range is called twice, first simply for | |
553 | * efficiency so that truncate_inode_pages does fewer | |
554 | * single-page unmaps. However after this first call, and | |
555 | * before truncate_inode_pages finishes, it is possible for | |
556 | * private pages to be COWed, which remain after | |
557 | * truncate_inode_pages finishes, hence the second | |
558 | * unmap_mapping_range call must be made for correctness. | |
559 | */ | |
560 | unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1); | |
561 | truncate_inode_pages(mapping, new); | |
562 | unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1); | |
25d9e2d1 | 563 | } |
564 | EXPORT_SYMBOL(truncate_pagecache); | |
565 | ||
2c27c65e CH |
566 | /** |
567 | * truncate_setsize - update inode and pagecache for a new file size | |
568 | * @inode: inode | |
569 | * @newsize: new file size | |
570 | * | |
382e27da JK |
571 | * truncate_setsize updates i_size and performs pagecache truncation (if |
572 | * necessary) to @newsize. It will be typically be called from the filesystem's | |
573 | * setattr function when ATTR_SIZE is passed in. | |
2c27c65e | 574 | * |
382e27da JK |
575 | * Must be called with inode_mutex held and before all filesystem specific |
576 | * block truncation has been performed. | |
2c27c65e CH |
577 | */ |
578 | void truncate_setsize(struct inode *inode, loff_t newsize) | |
579 | { | |
580 | loff_t oldsize; | |
581 | ||
582 | oldsize = inode->i_size; | |
583 | i_size_write(inode, newsize); | |
584 | ||
585 | truncate_pagecache(inode, oldsize, newsize); | |
586 | } | |
587 | EXPORT_SYMBOL(truncate_setsize); | |
588 | ||
25d9e2d1 | 589 | /** |
590 | * vmtruncate - unmap mappings "freed" by truncate() syscall | |
591 | * @inode: inode of the file used | |
592 | * @offset: file offset to start truncating | |
593 | * | |
2c27c65e CH |
594 | * This function is deprecated and truncate_setsize or truncate_pagecache |
595 | * should be used instead, together with filesystem specific block truncation. | |
25d9e2d1 | 596 | */ |
597 | int vmtruncate(struct inode *inode, loff_t offset) | |
598 | { | |
25d9e2d1 | 599 | int error; |
600 | ||
2c27c65e | 601 | error = inode_newsize_ok(inode, offset); |
25d9e2d1 | 602 | if (error) |
603 | return error; | |
7bb46a67 | 604 | |
2c27c65e | 605 | truncate_setsize(inode, offset); |
25d9e2d1 | 606 | if (inode->i_op->truncate) |
607 | inode->i_op->truncate(inode); | |
2c27c65e | 608 | return 0; |
25d9e2d1 | 609 | } |
610 | EXPORT_SYMBOL(vmtruncate); | |
5b8ba101 HD |
611 | |
612 | int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) | |
613 | { | |
614 | struct address_space *mapping = inode->i_mapping; | |
615 | ||
616 | /* | |
617 | * If the underlying filesystem is not going to provide | |
618 | * a way to truncate a range of blocks (punch a hole) - | |
619 | * we should return failure right now. | |
620 | */ | |
621 | if (!inode->i_op->truncate_range) | |
622 | return -ENOSYS; | |
623 | ||
624 | mutex_lock(&inode->i_mutex); | |
625 | down_write(&inode->i_alloc_sem); | |
626 | unmap_mapping_range(mapping, offset, (end - offset), 1); | |
5b8ba101 | 627 | inode->i_op->truncate_range(inode, offset, end); |
94c1e62d HD |
628 | /* unmap again to remove racily COWed private pages */ |
629 | unmap_mapping_range(mapping, offset, (end - offset), 1); | |
5b8ba101 HD |
630 | up_write(&inode->i_alloc_sem); |
631 | mutex_unlock(&inode->i_mutex); | |
632 | ||
633 | return 0; | |
634 | } |