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