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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> | |
12 | #include <linux/module.h> | |
13 | #include <linux/pagemap.h> | |
14 | #include <linux/pagevec.h> | |
15 | #include <linux/buffer_head.h> /* grr. try_to_release_page, | |
aaa4059b | 16 | do_invalidatepage */ |
1da177e4 LT |
17 | |
18 | ||
1da177e4 LT |
19 | static inline void truncate_partial_page(struct page *page, unsigned partial) |
20 | { | |
21 | memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial); | |
22 | if (PagePrivate(page)) | |
23 | do_invalidatepage(page, partial); | |
24 | } | |
25 | ||
26 | /* | |
27 | * If truncate cannot remove the fs-private metadata from the page, the page | |
28 | * becomes anonymous. It will be left on the LRU and may even be mapped into | |
29 | * user pagetables if we're racing with filemap_nopage(). | |
30 | * | |
31 | * We need to bale out if page->mapping is no longer equal to the original | |
32 | * mapping. This happens a) when the VM reclaimed the page while we waited on | |
33 | * its lock, b) when a concurrent invalidate_inode_pages got there first and | |
34 | * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. | |
35 | */ | |
36 | static void | |
37 | truncate_complete_page(struct address_space *mapping, struct page *page) | |
38 | { | |
39 | if (page->mapping != mapping) | |
40 | return; | |
41 | ||
42 | if (PagePrivate(page)) | |
43 | do_invalidatepage(page, 0); | |
44 | ||
45 | clear_page_dirty(page); | |
46 | ClearPageUptodate(page); | |
47 | ClearPageMappedToDisk(page); | |
48 | remove_from_page_cache(page); | |
49 | page_cache_release(page); /* pagecache ref */ | |
50 | } | |
51 | ||
52 | /* | |
53 | * This is for invalidate_inode_pages(). That function can be called at | |
54 | * any time, and is not supposed to throw away dirty pages. But pages can | |
55 | * be marked dirty at any time too. So we re-check the dirtiness inside | |
56 | * ->tree_lock. That provides exclusion against the __set_page_dirty | |
57 | * functions. | |
58 | * | |
59 | * Returns non-zero if the page was successfully invalidated. | |
60 | */ | |
61 | static int | |
62 | invalidate_complete_page(struct address_space *mapping, struct page *page) | |
63 | { | |
64 | if (page->mapping != mapping) | |
65 | return 0; | |
66 | ||
67 | if (PagePrivate(page) && !try_to_release_page(page, 0)) | |
68 | return 0; | |
69 | ||
70 | write_lock_irq(&mapping->tree_lock); | |
71 | if (PageDirty(page)) { | |
72 | write_unlock_irq(&mapping->tree_lock); | |
73 | return 0; | |
74 | } | |
75 | ||
76 | BUG_ON(PagePrivate(page)); | |
77 | __remove_from_page_cache(page); | |
78 | write_unlock_irq(&mapping->tree_lock); | |
79 | ClearPageUptodate(page); | |
80 | page_cache_release(page); /* pagecache ref */ | |
81 | return 1; | |
82 | } | |
83 | ||
84 | /** | |
d7339071 HR |
85 | * truncate_inode_pages - truncate range of pages specified by start and |
86 | * end byte offsets | |
1da177e4 LT |
87 | * @mapping: mapping to truncate |
88 | * @lstart: offset from which to truncate | |
d7339071 | 89 | * @lend: offset to which to truncate |
1da177e4 | 90 | * |
d7339071 HR |
91 | * Truncate the page cache, removing the pages that are between |
92 | * specified offsets (and zeroing out partial page | |
93 | * (if lstart is not page aligned)). | |
1da177e4 LT |
94 | * |
95 | * Truncate takes two passes - the first pass is nonblocking. It will not | |
96 | * block on page locks and it will not block on writeback. The second pass | |
97 | * will wait. This is to prevent as much IO as possible in the affected region. | |
98 | * The first pass will remove most pages, so the search cost of the second pass | |
99 | * is low. | |
100 | * | |
101 | * When looking at page->index outside the page lock we need to be careful to | |
102 | * copy it into a local to avoid races (it could change at any time). | |
103 | * | |
104 | * We pass down the cache-hot hint to the page freeing code. Even if the | |
105 | * mapping is large, it is probably the case that the final pages are the most | |
106 | * recently touched, and freeing happens in ascending file offset order. | |
1da177e4 | 107 | */ |
d7339071 HR |
108 | void truncate_inode_pages_range(struct address_space *mapping, |
109 | loff_t lstart, loff_t lend) | |
1da177e4 LT |
110 | { |
111 | const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; | |
d7339071 | 112 | pgoff_t end; |
1da177e4 LT |
113 | const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1); |
114 | struct pagevec pvec; | |
115 | pgoff_t next; | |
116 | int i; | |
117 | ||
118 | if (mapping->nrpages == 0) | |
119 | return; | |
120 | ||
d7339071 HR |
121 | BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1)); |
122 | end = (lend >> PAGE_CACHE_SHIFT); | |
123 | ||
1da177e4 LT |
124 | pagevec_init(&pvec, 0); |
125 | next = start; | |
d7339071 HR |
126 | while (next <= end && |
127 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
1da177e4 LT |
128 | for (i = 0; i < pagevec_count(&pvec); i++) { |
129 | struct page *page = pvec.pages[i]; | |
130 | pgoff_t page_index = page->index; | |
131 | ||
d7339071 HR |
132 | if (page_index > end) { |
133 | next = page_index; | |
134 | break; | |
135 | } | |
136 | ||
1da177e4 LT |
137 | if (page_index > next) |
138 | next = page_index; | |
139 | next++; | |
140 | if (TestSetPageLocked(page)) | |
141 | continue; | |
142 | if (PageWriteback(page)) { | |
143 | unlock_page(page); | |
144 | continue; | |
145 | } | |
146 | truncate_complete_page(mapping, page); | |
147 | unlock_page(page); | |
148 | } | |
149 | pagevec_release(&pvec); | |
150 | cond_resched(); | |
151 | } | |
152 | ||
153 | if (partial) { | |
154 | struct page *page = find_lock_page(mapping, start - 1); | |
155 | if (page) { | |
156 | wait_on_page_writeback(page); | |
157 | truncate_partial_page(page, partial); | |
158 | unlock_page(page); | |
159 | page_cache_release(page); | |
160 | } | |
161 | } | |
162 | ||
163 | next = start; | |
164 | for ( ; ; ) { | |
165 | cond_resched(); | |
166 | if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
167 | if (next == start) | |
168 | break; | |
169 | next = start; | |
170 | continue; | |
171 | } | |
d7339071 HR |
172 | if (pvec.pages[0]->index > end) { |
173 | pagevec_release(&pvec); | |
174 | break; | |
175 | } | |
1da177e4 LT |
176 | for (i = 0; i < pagevec_count(&pvec); i++) { |
177 | struct page *page = pvec.pages[i]; | |
178 | ||
d7339071 HR |
179 | if (page->index > end) |
180 | break; | |
1da177e4 LT |
181 | lock_page(page); |
182 | wait_on_page_writeback(page); | |
183 | if (page->index > next) | |
184 | next = page->index; | |
185 | next++; | |
186 | truncate_complete_page(mapping, page); | |
187 | unlock_page(page); | |
188 | } | |
189 | pagevec_release(&pvec); | |
190 | } | |
191 | } | |
d7339071 | 192 | EXPORT_SYMBOL(truncate_inode_pages_range); |
1da177e4 | 193 | |
d7339071 HR |
194 | /** |
195 | * truncate_inode_pages - truncate *all* the pages from an offset | |
196 | * @mapping: mapping to truncate | |
197 | * @lstart: offset from which to truncate | |
198 | * | |
199 | * Called under (and serialised by) inode->i_sem. | |
200 | */ | |
201 | void truncate_inode_pages(struct address_space *mapping, loff_t lstart) | |
202 | { | |
203 | truncate_inode_pages_range(mapping, lstart, (loff_t)-1); | |
204 | } | |
1da177e4 LT |
205 | EXPORT_SYMBOL(truncate_inode_pages); |
206 | ||
207 | /** | |
208 | * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode | |
209 | * @mapping: the address_space which holds the pages to invalidate | |
210 | * @start: the offset 'from' which to invalidate | |
211 | * @end: the offset 'to' which to invalidate (inclusive) | |
212 | * | |
213 | * This function only removes the unlocked pages, if you want to | |
214 | * remove all the pages of one inode, you must call truncate_inode_pages. | |
215 | * | |
216 | * invalidate_mapping_pages() will not block on IO activity. It will not | |
217 | * invalidate pages which are dirty, locked, under writeback or mapped into | |
218 | * pagetables. | |
219 | */ | |
220 | unsigned long invalidate_mapping_pages(struct address_space *mapping, | |
221 | pgoff_t start, pgoff_t end) | |
222 | { | |
223 | struct pagevec pvec; | |
224 | pgoff_t next = start; | |
225 | unsigned long ret = 0; | |
226 | int i; | |
227 | ||
228 | pagevec_init(&pvec, 0); | |
229 | while (next <= end && | |
230 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
231 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
232 | struct page *page = pvec.pages[i]; | |
233 | ||
234 | if (TestSetPageLocked(page)) { | |
235 | next++; | |
236 | continue; | |
237 | } | |
238 | if (page->index > next) | |
239 | next = page->index; | |
240 | next++; | |
241 | if (PageDirty(page) || PageWriteback(page)) | |
242 | goto unlock; | |
243 | if (page_mapped(page)) | |
244 | goto unlock; | |
245 | ret += invalidate_complete_page(mapping, page); | |
246 | unlock: | |
247 | unlock_page(page); | |
248 | if (next > end) | |
249 | break; | |
250 | } | |
251 | pagevec_release(&pvec); | |
1da177e4 LT |
252 | } |
253 | return ret; | |
254 | } | |
255 | ||
256 | unsigned long invalidate_inode_pages(struct address_space *mapping) | |
257 | { | |
258 | return invalidate_mapping_pages(mapping, 0, ~0UL); | |
259 | } | |
260 | ||
261 | EXPORT_SYMBOL(invalidate_inode_pages); | |
262 | ||
263 | /** | |
264 | * invalidate_inode_pages2_range - remove range of pages from an address_space | |
67be2dd1 | 265 | * @mapping: the address_space |
1da177e4 LT |
266 | * @start: the page offset 'from' which to invalidate |
267 | * @end: the page offset 'to' which to invalidate (inclusive) | |
268 | * | |
269 | * Any pages which are found to be mapped into pagetables are unmapped prior to | |
270 | * invalidation. | |
271 | * | |
272 | * Returns -EIO if any pages could not be invalidated. | |
273 | */ | |
274 | int invalidate_inode_pages2_range(struct address_space *mapping, | |
275 | pgoff_t start, pgoff_t end) | |
276 | { | |
277 | struct pagevec pvec; | |
278 | pgoff_t next; | |
279 | int i; | |
280 | int ret = 0; | |
281 | int did_range_unmap = 0; | |
282 | int wrapped = 0; | |
283 | ||
284 | pagevec_init(&pvec, 0); | |
285 | next = start; | |
286 | while (next <= end && !ret && !wrapped && | |
287 | pagevec_lookup(&pvec, mapping, next, | |
288 | min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) { | |
289 | for (i = 0; !ret && i < pagevec_count(&pvec); i++) { | |
290 | struct page *page = pvec.pages[i]; | |
291 | pgoff_t page_index; | |
292 | int was_dirty; | |
293 | ||
294 | lock_page(page); | |
295 | if (page->mapping != mapping) { | |
296 | unlock_page(page); | |
297 | continue; | |
298 | } | |
299 | page_index = page->index; | |
300 | next = page_index + 1; | |
301 | if (next == 0) | |
302 | wrapped = 1; | |
303 | if (page_index > end) { | |
304 | unlock_page(page); | |
305 | break; | |
306 | } | |
307 | wait_on_page_writeback(page); | |
308 | while (page_mapped(page)) { | |
309 | if (!did_range_unmap) { | |
310 | /* | |
311 | * Zap the rest of the file in one hit. | |
312 | */ | |
313 | unmap_mapping_range(mapping, | |
479ef592 OD |
314 | (loff_t)page_index<<PAGE_CACHE_SHIFT, |
315 | (loff_t)(end - page_index + 1) | |
1da177e4 LT |
316 | << PAGE_CACHE_SHIFT, |
317 | 0); | |
318 | did_range_unmap = 1; | |
319 | } else { | |
320 | /* | |
321 | * Just zap this page | |
322 | */ | |
323 | unmap_mapping_range(mapping, | |
479ef592 | 324 | (loff_t)page_index<<PAGE_CACHE_SHIFT, |
1da177e4 LT |
325 | PAGE_CACHE_SIZE, 0); |
326 | } | |
327 | } | |
328 | was_dirty = test_clear_page_dirty(page); | |
329 | if (!invalidate_complete_page(mapping, page)) { | |
330 | if (was_dirty) | |
331 | set_page_dirty(page); | |
332 | ret = -EIO; | |
333 | } | |
334 | unlock_page(page); | |
335 | } | |
336 | pagevec_release(&pvec); | |
337 | cond_resched(); | |
338 | } | |
339 | return ret; | |
340 | } | |
341 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range); | |
342 | ||
343 | /** | |
344 | * invalidate_inode_pages2 - remove all pages from an address_space | |
67be2dd1 | 345 | * @mapping: the address_space |
1da177e4 LT |
346 | * |
347 | * Any pages which are found to be mapped into pagetables are unmapped prior to | |
348 | * invalidation. | |
349 | * | |
350 | * Returns -EIO if any pages could not be invalidated. | |
351 | */ | |
352 | int invalidate_inode_pages2(struct address_space *mapping) | |
353 | { | |
354 | return invalidate_inode_pages2_range(mapping, 0, -1); | |
355 | } | |
356 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2); |