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