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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 | * | |
6 | * 10Sep2002 akpm@zip.com.au | |
7 | * Initial version. | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/mm.h> | |
0fd0e6b0 | 12 | #include <linux/swap.h> |
1da177e4 LT |
13 | #include <linux/module.h> |
14 | #include <linux/pagemap.h> | |
15 | #include <linux/pagevec.h> | |
e08748ce | 16 | #include <linux/task_io_accounting_ops.h> |
1da177e4 | 17 | #include <linux/buffer_head.h> /* grr. try_to_release_page, |
aaa4059b | 18 | do_invalidatepage */ |
1da177e4 LT |
19 | |
20 | ||
cf9a2ae8 DH |
21 | /** |
22 | * do_invalidatepage - invalidate part of all of a page | |
23 | * @page: the page which is affected | |
24 | * @offset: the index of the truncation point | |
25 | * | |
26 | * do_invalidatepage() is called when all or part of the page has become | |
27 | * invalidated by a truncate operation. | |
28 | * | |
29 | * do_invalidatepage() does not have to release all buffers, but it must | |
30 | * ensure that no dirty buffer is left outside @offset and that no I/O | |
31 | * is underway against any of the blocks which are outside the truncation | |
32 | * point. Because the caller is about to free (and possibly reuse) those | |
33 | * blocks on-disk. | |
34 | */ | |
35 | void do_invalidatepage(struct page *page, unsigned long offset) | |
36 | { | |
37 | void (*invalidatepage)(struct page *, unsigned long); | |
38 | invalidatepage = page->mapping->a_ops->invalidatepage; | |
9361401e | 39 | #ifdef CONFIG_BLOCK |
cf9a2ae8 DH |
40 | if (!invalidatepage) |
41 | invalidatepage = block_invalidatepage; | |
9361401e | 42 | #endif |
cf9a2ae8 DH |
43 | if (invalidatepage) |
44 | (*invalidatepage)(page, offset); | |
45 | } | |
46 | ||
1da177e4 LT |
47 | static inline void truncate_partial_page(struct page *page, unsigned partial) |
48 | { | |
49 | memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial); | |
50 | if (PagePrivate(page)) | |
51 | do_invalidatepage(page, partial); | |
52 | } | |
53 | ||
fba2591b LT |
54 | void cancel_dirty_page(struct page *page, unsigned int account_size) |
55 | { | |
56 | /* If we're cancelling the page, it had better not be mapped any more */ | |
57 | if (page_mapped(page)) { | |
58 | static unsigned int warncount; | |
59 | ||
60 | WARN_ON(++warncount < 5); | |
61 | } | |
62 | ||
8368e328 LT |
63 | if (TestClearPageDirty(page)) { |
64 | struct address_space *mapping = page->mapping; | |
65 | if (mapping && mapping_cap_account_dirty(mapping)) { | |
66 | dec_zone_page_state(page, NR_FILE_DIRTY); | |
67 | if (account_size) | |
68 | task_io_account_cancelled_write(account_size); | |
69 | } | |
3e67c098 | 70 | } |
fba2591b | 71 | } |
8368e328 | 72 | EXPORT_SYMBOL(cancel_dirty_page); |
fba2591b | 73 | |
1da177e4 LT |
74 | /* |
75 | * If truncate cannot remove the fs-private metadata from the page, the page | |
76 | * becomes anonymous. It will be left on the LRU and may even be mapped into | |
77 | * user pagetables if we're racing with filemap_nopage(). | |
78 | * | |
79 | * We need to bale out if page->mapping is no longer equal to the original | |
80 | * mapping. This happens a) when the VM reclaimed the page while we waited on | |
81 | * its lock, b) when a concurrent invalidate_inode_pages got there first and | |
82 | * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. | |
83 | */ | |
84 | static void | |
85 | truncate_complete_page(struct address_space *mapping, struct page *page) | |
86 | { | |
87 | if (page->mapping != mapping) | |
88 | return; | |
89 | ||
3e67c098 AM |
90 | cancel_dirty_page(page, PAGE_CACHE_SIZE); |
91 | ||
1da177e4 LT |
92 | if (PagePrivate(page)) |
93 | do_invalidatepage(page, 0); | |
94 | ||
1da177e4 LT |
95 | ClearPageUptodate(page); |
96 | ClearPageMappedToDisk(page); | |
97 | remove_from_page_cache(page); | |
98 | page_cache_release(page); /* pagecache ref */ | |
99 | } | |
100 | ||
101 | /* | |
102 | * This is for invalidate_inode_pages(). That function can be called at | |
103 | * any time, and is not supposed to throw away dirty pages. But pages can | |
0fd0e6b0 NP |
104 | * be marked dirty at any time too, so use remove_mapping which safely |
105 | * discards clean, unused pages. | |
1da177e4 LT |
106 | * |
107 | * Returns non-zero if the page was successfully invalidated. | |
108 | */ | |
109 | static int | |
110 | invalidate_complete_page(struct address_space *mapping, struct page *page) | |
111 | { | |
0fd0e6b0 NP |
112 | int ret; |
113 | ||
1da177e4 LT |
114 | if (page->mapping != mapping) |
115 | return 0; | |
116 | ||
117 | if (PagePrivate(page) && !try_to_release_page(page, 0)) | |
118 | return 0; | |
119 | ||
0fd0e6b0 | 120 | ret = remove_mapping(mapping, page); |
0fd0e6b0 NP |
121 | |
122 | return ret; | |
1da177e4 LT |
123 | } |
124 | ||
125 | /** | |
d7339071 HR |
126 | * truncate_inode_pages - truncate range of pages specified by start and |
127 | * end byte offsets | |
1da177e4 LT |
128 | * @mapping: mapping to truncate |
129 | * @lstart: offset from which to truncate | |
d7339071 | 130 | * @lend: offset to which to truncate |
1da177e4 | 131 | * |
d7339071 HR |
132 | * Truncate the page cache, removing the pages that are between |
133 | * specified offsets (and zeroing out partial page | |
134 | * (if lstart is not page aligned)). | |
1da177e4 LT |
135 | * |
136 | * Truncate takes two passes - the first pass is nonblocking. It will not | |
137 | * block on page locks and it will not block on writeback. The second pass | |
138 | * will wait. This is to prevent as much IO as possible in the affected region. | |
139 | * The first pass will remove most pages, so the search cost of the second pass | |
140 | * is low. | |
141 | * | |
142 | * When looking at page->index outside the page lock we need to be careful to | |
143 | * copy it into a local to avoid races (it could change at any time). | |
144 | * | |
145 | * We pass down the cache-hot hint to the page freeing code. Even if the | |
146 | * mapping is large, it is probably the case that the final pages are the most | |
147 | * recently touched, and freeing happens in ascending file offset order. | |
1da177e4 | 148 | */ |
d7339071 HR |
149 | void truncate_inode_pages_range(struct address_space *mapping, |
150 | loff_t lstart, loff_t lend) | |
1da177e4 LT |
151 | { |
152 | const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; | |
d7339071 | 153 | pgoff_t end; |
1da177e4 LT |
154 | const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1); |
155 | struct pagevec pvec; | |
156 | pgoff_t next; | |
157 | int i; | |
158 | ||
159 | if (mapping->nrpages == 0) | |
160 | return; | |
161 | ||
d7339071 HR |
162 | BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1)); |
163 | end = (lend >> PAGE_CACHE_SHIFT); | |
164 | ||
1da177e4 LT |
165 | pagevec_init(&pvec, 0); |
166 | next = start; | |
d7339071 HR |
167 | while (next <= end && |
168 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
1da177e4 LT |
169 | for (i = 0; i < pagevec_count(&pvec); i++) { |
170 | struct page *page = pvec.pages[i]; | |
171 | pgoff_t page_index = page->index; | |
172 | ||
d7339071 HR |
173 | if (page_index > end) { |
174 | next = page_index; | |
175 | break; | |
176 | } | |
177 | ||
1da177e4 LT |
178 | if (page_index > next) |
179 | next = page_index; | |
180 | next++; | |
181 | if (TestSetPageLocked(page)) | |
182 | continue; | |
183 | if (PageWriteback(page)) { | |
184 | unlock_page(page); | |
185 | continue; | |
186 | } | |
187 | truncate_complete_page(mapping, page); | |
188 | unlock_page(page); | |
189 | } | |
190 | pagevec_release(&pvec); | |
191 | cond_resched(); | |
192 | } | |
193 | ||
194 | if (partial) { | |
195 | struct page *page = find_lock_page(mapping, start - 1); | |
196 | if (page) { | |
197 | wait_on_page_writeback(page); | |
198 | truncate_partial_page(page, partial); | |
199 | unlock_page(page); | |
200 | page_cache_release(page); | |
201 | } | |
202 | } | |
203 | ||
204 | next = start; | |
205 | for ( ; ; ) { | |
206 | cond_resched(); | |
207 | if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
208 | if (next == start) | |
209 | break; | |
210 | next = start; | |
211 | continue; | |
212 | } | |
d7339071 HR |
213 | if (pvec.pages[0]->index > end) { |
214 | pagevec_release(&pvec); | |
215 | break; | |
216 | } | |
1da177e4 LT |
217 | for (i = 0; i < pagevec_count(&pvec); i++) { |
218 | struct page *page = pvec.pages[i]; | |
219 | ||
d7339071 HR |
220 | if (page->index > end) |
221 | break; | |
1da177e4 LT |
222 | lock_page(page); |
223 | wait_on_page_writeback(page); | |
224 | if (page->index > next) | |
225 | next = page->index; | |
226 | next++; | |
227 | truncate_complete_page(mapping, page); | |
228 | unlock_page(page); | |
229 | } | |
230 | pagevec_release(&pvec); | |
231 | } | |
232 | } | |
d7339071 | 233 | EXPORT_SYMBOL(truncate_inode_pages_range); |
1da177e4 | 234 | |
d7339071 HR |
235 | /** |
236 | * truncate_inode_pages - truncate *all* the pages from an offset | |
237 | * @mapping: mapping to truncate | |
238 | * @lstart: offset from which to truncate | |
239 | * | |
1b1dcc1b | 240 | * Called under (and serialised by) inode->i_mutex. |
d7339071 HR |
241 | */ |
242 | void truncate_inode_pages(struct address_space *mapping, loff_t lstart) | |
243 | { | |
244 | truncate_inode_pages_range(mapping, lstart, (loff_t)-1); | |
245 | } | |
1da177e4 LT |
246 | EXPORT_SYMBOL(truncate_inode_pages); |
247 | ||
248 | /** | |
249 | * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode | |
250 | * @mapping: the address_space which holds the pages to invalidate | |
251 | * @start: the offset 'from' which to invalidate | |
252 | * @end: the offset 'to' which to invalidate (inclusive) | |
253 | * | |
254 | * This function only removes the unlocked pages, if you want to | |
255 | * remove all the pages of one inode, you must call truncate_inode_pages. | |
256 | * | |
257 | * invalidate_mapping_pages() will not block on IO activity. It will not | |
258 | * invalidate pages which are dirty, locked, under writeback or mapped into | |
259 | * pagetables. | |
260 | */ | |
261 | unsigned long invalidate_mapping_pages(struct address_space *mapping, | |
262 | pgoff_t start, pgoff_t end) | |
263 | { | |
264 | struct pagevec pvec; | |
265 | pgoff_t next = start; | |
266 | unsigned long ret = 0; | |
267 | int i; | |
268 | ||
269 | pagevec_init(&pvec, 0); | |
270 | while (next <= end && | |
271 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
272 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
273 | struct page *page = pvec.pages[i]; | |
e0f23603 N |
274 | pgoff_t index; |
275 | int lock_failed; | |
1da177e4 | 276 | |
e0f23603 N |
277 | lock_failed = TestSetPageLocked(page); |
278 | ||
279 | /* | |
280 | * We really shouldn't be looking at the ->index of an | |
281 | * unlocked page. But we're not allowed to lock these | |
282 | * pages. So we rely upon nobody altering the ->index | |
283 | * of this (pinned-by-us) page. | |
284 | */ | |
285 | index = page->index; | |
286 | if (index > next) | |
287 | next = index; | |
1da177e4 | 288 | next++; |
e0f23603 N |
289 | if (lock_failed) |
290 | continue; | |
291 | ||
1da177e4 LT |
292 | if (PageDirty(page) || PageWriteback(page)) |
293 | goto unlock; | |
294 | if (page_mapped(page)) | |
295 | goto unlock; | |
296 | ret += invalidate_complete_page(mapping, page); | |
297 | unlock: | |
298 | unlock_page(page); | |
299 | if (next > end) | |
300 | break; | |
301 | } | |
302 | pagevec_release(&pvec); | |
1da177e4 LT |
303 | } |
304 | return ret; | |
305 | } | |
306 | ||
307 | unsigned long invalidate_inode_pages(struct address_space *mapping) | |
308 | { | |
309 | return invalidate_mapping_pages(mapping, 0, ~0UL); | |
310 | } | |
1da177e4 LT |
311 | EXPORT_SYMBOL(invalidate_inode_pages); |
312 | ||
bd4c8ce4 AM |
313 | /* |
314 | * This is like invalidate_complete_page(), except it ignores the page's | |
315 | * refcount. We do this because invalidate_inode_pages2() needs stronger | |
316 | * invalidation guarantees, and cannot afford to leave pages behind because | |
317 | * shrink_list() has a temp ref on them, or because they're transiently sitting | |
318 | * in the lru_cache_add() pagevecs. | |
319 | */ | |
320 | static int | |
321 | invalidate_complete_page2(struct address_space *mapping, struct page *page) | |
322 | { | |
323 | if (page->mapping != mapping) | |
324 | return 0; | |
325 | ||
887ed2f3 | 326 | if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL)) |
bd4c8ce4 AM |
327 | return 0; |
328 | ||
329 | write_lock_irq(&mapping->tree_lock); | |
330 | if (PageDirty(page)) | |
331 | goto failed; | |
332 | ||
333 | BUG_ON(PagePrivate(page)); | |
334 | __remove_from_page_cache(page); | |
335 | write_unlock_irq(&mapping->tree_lock); | |
336 | ClearPageUptodate(page); | |
337 | page_cache_release(page); /* pagecache ref */ | |
338 | return 1; | |
339 | failed: | |
340 | write_unlock_irq(&mapping->tree_lock); | |
341 | return 0; | |
342 | } | |
343 | ||
1da177e4 LT |
344 | /** |
345 | * invalidate_inode_pages2_range - remove range of pages from an address_space | |
67be2dd1 | 346 | * @mapping: the address_space |
1da177e4 LT |
347 | * @start: the page offset 'from' which to invalidate |
348 | * @end: the page offset 'to' which to invalidate (inclusive) | |
349 | * | |
350 | * Any pages which are found to be mapped into pagetables are unmapped prior to | |
351 | * invalidation. | |
352 | * | |
353 | * Returns -EIO if any pages could not be invalidated. | |
354 | */ | |
355 | int invalidate_inode_pages2_range(struct address_space *mapping, | |
356 | pgoff_t start, pgoff_t end) | |
357 | { | |
358 | struct pagevec pvec; | |
359 | pgoff_t next; | |
360 | int i; | |
361 | int ret = 0; | |
362 | int did_range_unmap = 0; | |
363 | int wrapped = 0; | |
364 | ||
365 | pagevec_init(&pvec, 0); | |
366 | next = start; | |
367 | while (next <= end && !ret && !wrapped && | |
368 | pagevec_lookup(&pvec, mapping, next, | |
369 | min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) { | |
370 | for (i = 0; !ret && i < pagevec_count(&pvec); i++) { | |
371 | struct page *page = pvec.pages[i]; | |
372 | pgoff_t page_index; | |
1da177e4 LT |
373 | |
374 | lock_page(page); | |
375 | if (page->mapping != mapping) { | |
376 | unlock_page(page); | |
377 | continue; | |
378 | } | |
379 | page_index = page->index; | |
380 | next = page_index + 1; | |
381 | if (next == 0) | |
382 | wrapped = 1; | |
383 | if (page_index > end) { | |
384 | unlock_page(page); | |
385 | break; | |
386 | } | |
387 | wait_on_page_writeback(page); | |
388 | while (page_mapped(page)) { | |
389 | if (!did_range_unmap) { | |
390 | /* | |
391 | * Zap the rest of the file in one hit. | |
392 | */ | |
393 | unmap_mapping_range(mapping, | |
479ef592 OD |
394 | (loff_t)page_index<<PAGE_CACHE_SHIFT, |
395 | (loff_t)(end - page_index + 1) | |
1da177e4 LT |
396 | << PAGE_CACHE_SHIFT, |
397 | 0); | |
398 | did_range_unmap = 1; | |
399 | } else { | |
400 | /* | |
401 | * Just zap this page | |
402 | */ | |
403 | unmap_mapping_range(mapping, | |
479ef592 | 404 | (loff_t)page_index<<PAGE_CACHE_SHIFT, |
1da177e4 LT |
405 | PAGE_CACHE_SIZE, 0); |
406 | } | |
407 | } | |
fba2591b | 408 | if (!invalidate_complete_page2(mapping, page)) |
1da177e4 | 409 | ret = -EIO; |
1da177e4 LT |
410 | unlock_page(page); |
411 | } | |
412 | pagevec_release(&pvec); | |
413 | cond_resched(); | |
414 | } | |
8258d4a5 | 415 | WARN_ON_ONCE(ret); |
1da177e4 LT |
416 | return ret; |
417 | } | |
418 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range); | |
419 | ||
420 | /** | |
421 | * invalidate_inode_pages2 - remove all pages from an address_space | |
67be2dd1 | 422 | * @mapping: the address_space |
1da177e4 LT |
423 | * |
424 | * Any pages which are found to be mapped into pagetables are unmapped prior to | |
425 | * invalidation. | |
426 | * | |
427 | * Returns -EIO if any pages could not be invalidated. | |
428 | */ | |
429 | int invalidate_inode_pages2(struct address_space *mapping) | |
430 | { | |
431 | return invalidate_inode_pages2_range(mapping, 0, -1); | |
432 | } | |
433 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2); |