Commit | Line | Data |
---|---|---|
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> | |
4af3c9cc | 11 | #include <linux/backing-dev.h> |
1da177e4 | 12 | #include <linux/mm.h> |
0fd0e6b0 | 13 | #include <linux/swap.h> |
1da177e4 LT |
14 | #include <linux/module.h> |
15 | #include <linux/pagemap.h> | |
01f2705d | 16 | #include <linux/highmem.h> |
1da177e4 | 17 | #include <linux/pagevec.h> |
e08748ce | 18 | #include <linux/task_io_accounting_ops.h> |
1da177e4 | 19 | #include <linux/buffer_head.h> /* grr. try_to_release_page, |
aaa4059b | 20 | do_invalidatepage */ |
1da177e4 LT |
21 | |
22 | ||
cf9a2ae8 | 23 | /** |
28bc44d7 | 24 | * do_invalidatepage - invalidate part or all of a page |
cf9a2ae8 DH |
25 | * @page: the page which is affected |
26 | * @offset: the index of the truncation point | |
27 | * | |
28 | * do_invalidatepage() is called when all or part of the page has become | |
29 | * invalidated by a truncate operation. | |
30 | * | |
31 | * do_invalidatepage() does not have to release all buffers, but it must | |
32 | * ensure that no dirty buffer is left outside @offset and that no I/O | |
33 | * is underway against any of the blocks which are outside the truncation | |
34 | * point. Because the caller is about to free (and possibly reuse) those | |
35 | * blocks on-disk. | |
36 | */ | |
37 | void do_invalidatepage(struct page *page, unsigned long offset) | |
38 | { | |
39 | void (*invalidatepage)(struct page *, unsigned long); | |
40 | invalidatepage = page->mapping->a_ops->invalidatepage; | |
9361401e | 41 | #ifdef CONFIG_BLOCK |
cf9a2ae8 DH |
42 | if (!invalidatepage) |
43 | invalidatepage = block_invalidatepage; | |
9361401e | 44 | #endif |
cf9a2ae8 DH |
45 | if (invalidatepage) |
46 | (*invalidatepage)(page, offset); | |
47 | } | |
48 | ||
1da177e4 LT |
49 | static inline void truncate_partial_page(struct page *page, unsigned partial) |
50 | { | |
eebd2aa3 | 51 | zero_user_segment(page, partial, PAGE_CACHE_SIZE); |
1da177e4 LT |
52 | if (PagePrivate(page)) |
53 | do_invalidatepage(page, partial); | |
54 | } | |
55 | ||
ecdfc978 LT |
56 | /* |
57 | * This cancels just the dirty bit on the kernel page itself, it | |
58 | * does NOT actually remove dirty bits on any mmap's that may be | |
59 | * around. It also leaves the page tagged dirty, so any sync | |
60 | * activity will still find it on the dirty lists, and in particular, | |
61 | * clear_page_dirty_for_io() will still look at the dirty bits in | |
62 | * the VM. | |
63 | * | |
64 | * Doing this should *normally* only ever be done when a page | |
65 | * is truncated, and is not actually mapped anywhere at all. However, | |
66 | * fs/buffer.c does this when it notices that somebody has cleaned | |
67 | * out all the buffers on a page without actually doing it through | |
68 | * the VM. Can you say "ext3 is horribly ugly"? Tought you could. | |
69 | */ | |
fba2591b LT |
70 | void cancel_dirty_page(struct page *page, unsigned int account_size) |
71 | { | |
8368e328 LT |
72 | if (TestClearPageDirty(page)) { |
73 | struct address_space *mapping = page->mapping; | |
74 | if (mapping && mapping_cap_account_dirty(mapping)) { | |
75 | dec_zone_page_state(page, NR_FILE_DIRTY); | |
c9e51e41 PZ |
76 | dec_bdi_stat(mapping->backing_dev_info, |
77 | BDI_RECLAIMABLE); | |
8368e328 LT |
78 | if (account_size) |
79 | task_io_account_cancelled_write(account_size); | |
80 | } | |
3e67c098 | 81 | } |
fba2591b | 82 | } |
8368e328 | 83 | EXPORT_SYMBOL(cancel_dirty_page); |
fba2591b | 84 | |
1da177e4 LT |
85 | /* |
86 | * If truncate cannot remove the fs-private metadata from the page, the page | |
87 | * becomes anonymous. It will be left on the LRU and may even be mapped into | |
54cb8821 | 88 | * user pagetables if we're racing with filemap_fault(). |
1da177e4 LT |
89 | * |
90 | * We need to bale out if page->mapping is no longer equal to the original | |
91 | * mapping. This happens a) when the VM reclaimed the page while we waited on | |
fc0ecff6 | 92 | * its lock, b) when a concurrent invalidate_mapping_pages got there first and |
1da177e4 LT |
93 | * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. |
94 | */ | |
95 | static void | |
96 | truncate_complete_page(struct address_space *mapping, struct page *page) | |
97 | { | |
98 | if (page->mapping != mapping) | |
99 | return; | |
100 | ||
101 | if (PagePrivate(page)) | |
102 | do_invalidatepage(page, 0); | |
103 | ||
a2b34564 BS |
104 | cancel_dirty_page(page, PAGE_CACHE_SIZE); |
105 | ||
787d2214 | 106 | remove_from_page_cache(page); |
1da177e4 LT |
107 | ClearPageUptodate(page); |
108 | ClearPageMappedToDisk(page); | |
1da177e4 LT |
109 | page_cache_release(page); /* pagecache ref */ |
110 | } | |
111 | ||
112 | /* | |
fc0ecff6 | 113 | * This is for invalidate_mapping_pages(). That function can be called at |
1da177e4 | 114 | * any time, and is not supposed to throw away dirty pages. But pages can |
0fd0e6b0 NP |
115 | * be marked dirty at any time too, so use remove_mapping which safely |
116 | * discards clean, unused pages. | |
1da177e4 LT |
117 | * |
118 | * Returns non-zero if the page was successfully invalidated. | |
119 | */ | |
120 | static int | |
121 | invalidate_complete_page(struct address_space *mapping, struct page *page) | |
122 | { | |
0fd0e6b0 NP |
123 | int ret; |
124 | ||
1da177e4 LT |
125 | if (page->mapping != mapping) |
126 | return 0; | |
127 | ||
128 | if (PagePrivate(page) && !try_to_release_page(page, 0)) | |
129 | return 0; | |
130 | ||
0fd0e6b0 | 131 | ret = remove_mapping(mapping, page); |
0fd0e6b0 NP |
132 | |
133 | return ret; | |
1da177e4 LT |
134 | } |
135 | ||
136 | /** | |
d7339071 HR |
137 | * truncate_inode_pages - truncate range of pages specified by start and |
138 | * end byte offsets | |
1da177e4 LT |
139 | * @mapping: mapping to truncate |
140 | * @lstart: offset from which to truncate | |
d7339071 | 141 | * @lend: offset to which to truncate |
1da177e4 | 142 | * |
d7339071 HR |
143 | * Truncate the page cache, removing the pages that are between |
144 | * specified offsets (and zeroing out partial page | |
145 | * (if lstart is not page aligned)). | |
1da177e4 LT |
146 | * |
147 | * Truncate takes two passes - the first pass is nonblocking. It will not | |
148 | * block on page locks and it will not block on writeback. The second pass | |
149 | * will wait. This is to prevent as much IO as possible in the affected region. | |
150 | * The first pass will remove most pages, so the search cost of the second pass | |
151 | * is low. | |
152 | * | |
153 | * When looking at page->index outside the page lock we need to be careful to | |
154 | * copy it into a local to avoid races (it could change at any time). | |
155 | * | |
156 | * We pass down the cache-hot hint to the page freeing code. Even if the | |
157 | * mapping is large, it is probably the case that the final pages are the most | |
158 | * recently touched, and freeing happens in ascending file offset order. | |
1da177e4 | 159 | */ |
d7339071 HR |
160 | void truncate_inode_pages_range(struct address_space *mapping, |
161 | loff_t lstart, loff_t lend) | |
1da177e4 LT |
162 | { |
163 | const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; | |
d7339071 | 164 | pgoff_t end; |
1da177e4 LT |
165 | const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1); |
166 | struct pagevec pvec; | |
167 | pgoff_t next; | |
168 | int i; | |
169 | ||
170 | if (mapping->nrpages == 0) | |
171 | return; | |
172 | ||
d7339071 HR |
173 | BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1)); |
174 | end = (lend >> PAGE_CACHE_SHIFT); | |
175 | ||
1da177e4 LT |
176 | pagevec_init(&pvec, 0); |
177 | next = start; | |
d7339071 HR |
178 | while (next <= end && |
179 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
1da177e4 LT |
180 | for (i = 0; i < pagevec_count(&pvec); i++) { |
181 | struct page *page = pvec.pages[i]; | |
182 | pgoff_t page_index = page->index; | |
183 | ||
d7339071 HR |
184 | if (page_index > end) { |
185 | next = page_index; | |
186 | break; | |
187 | } | |
188 | ||
1da177e4 LT |
189 | if (page_index > next) |
190 | next = page_index; | |
191 | next++; | |
192 | if (TestSetPageLocked(page)) | |
193 | continue; | |
194 | if (PageWriteback(page)) { | |
195 | unlock_page(page); | |
196 | continue; | |
197 | } | |
d00806b1 NP |
198 | if (page_mapped(page)) { |
199 | unmap_mapping_range(mapping, | |
200 | (loff_t)page_index<<PAGE_CACHE_SHIFT, | |
201 | PAGE_CACHE_SIZE, 0); | |
202 | } | |
1da177e4 LT |
203 | truncate_complete_page(mapping, page); |
204 | unlock_page(page); | |
205 | } | |
206 | pagevec_release(&pvec); | |
207 | cond_resched(); | |
208 | } | |
209 | ||
210 | if (partial) { | |
211 | struct page *page = find_lock_page(mapping, start - 1); | |
212 | if (page) { | |
213 | wait_on_page_writeback(page); | |
214 | truncate_partial_page(page, partial); | |
215 | unlock_page(page); | |
216 | page_cache_release(page); | |
217 | } | |
218 | } | |
219 | ||
220 | next = start; | |
221 | for ( ; ; ) { | |
222 | cond_resched(); | |
223 | if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
224 | if (next == start) | |
225 | break; | |
226 | next = start; | |
227 | continue; | |
228 | } | |
d7339071 HR |
229 | if (pvec.pages[0]->index > end) { |
230 | pagevec_release(&pvec); | |
231 | break; | |
232 | } | |
1da177e4 LT |
233 | for (i = 0; i < pagevec_count(&pvec); i++) { |
234 | struct page *page = pvec.pages[i]; | |
235 | ||
d7339071 HR |
236 | if (page->index > end) |
237 | break; | |
1da177e4 LT |
238 | lock_page(page); |
239 | wait_on_page_writeback(page); | |
d00806b1 NP |
240 | if (page_mapped(page)) { |
241 | unmap_mapping_range(mapping, | |
242 | (loff_t)page->index<<PAGE_CACHE_SHIFT, | |
243 | PAGE_CACHE_SIZE, 0); | |
244 | } | |
1da177e4 LT |
245 | if (page->index > next) |
246 | next = page->index; | |
247 | next++; | |
248 | truncate_complete_page(mapping, page); | |
249 | unlock_page(page); | |
250 | } | |
251 | pagevec_release(&pvec); | |
252 | } | |
253 | } | |
d7339071 | 254 | EXPORT_SYMBOL(truncate_inode_pages_range); |
1da177e4 | 255 | |
d7339071 HR |
256 | /** |
257 | * truncate_inode_pages - truncate *all* the pages from an offset | |
258 | * @mapping: mapping to truncate | |
259 | * @lstart: offset from which to truncate | |
260 | * | |
1b1dcc1b | 261 | * Called under (and serialised by) inode->i_mutex. |
d7339071 HR |
262 | */ |
263 | void truncate_inode_pages(struct address_space *mapping, loff_t lstart) | |
264 | { | |
265 | truncate_inode_pages_range(mapping, lstart, (loff_t)-1); | |
266 | } | |
1da177e4 LT |
267 | EXPORT_SYMBOL(truncate_inode_pages); |
268 | ||
fc9a07e7 AM |
269 | unsigned long __invalidate_mapping_pages(struct address_space *mapping, |
270 | pgoff_t start, pgoff_t end, bool be_atomic) | |
1da177e4 LT |
271 | { |
272 | struct pagevec pvec; | |
273 | pgoff_t next = start; | |
274 | unsigned long ret = 0; | |
275 | int i; | |
276 | ||
277 | pagevec_init(&pvec, 0); | |
278 | while (next <= end && | |
279 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { | |
280 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
281 | struct page *page = pvec.pages[i]; | |
e0f23603 N |
282 | pgoff_t index; |
283 | int lock_failed; | |
1da177e4 | 284 | |
e0f23603 N |
285 | lock_failed = TestSetPageLocked(page); |
286 | ||
287 | /* | |
288 | * We really shouldn't be looking at the ->index of an | |
289 | * unlocked page. But we're not allowed to lock these | |
290 | * pages. So we rely upon nobody altering the ->index | |
291 | * of this (pinned-by-us) page. | |
292 | */ | |
293 | index = page->index; | |
294 | if (index > next) | |
295 | next = index; | |
1da177e4 | 296 | next++; |
e0f23603 N |
297 | if (lock_failed) |
298 | continue; | |
299 | ||
1da177e4 LT |
300 | if (PageDirty(page) || PageWriteback(page)) |
301 | goto unlock; | |
302 | if (page_mapped(page)) | |
303 | goto unlock; | |
304 | ret += invalidate_complete_page(mapping, page); | |
305 | unlock: | |
306 | unlock_page(page); | |
307 | if (next > end) | |
308 | break; | |
309 | } | |
310 | pagevec_release(&pvec); | |
fc9a07e7 AM |
311 | if (likely(!be_atomic)) |
312 | cond_resched(); | |
1da177e4 LT |
313 | } |
314 | return ret; | |
315 | } | |
fc9a07e7 AM |
316 | |
317 | /** | |
318 | * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode | |
319 | * @mapping: the address_space which holds the pages to invalidate | |
320 | * @start: the offset 'from' which to invalidate | |
321 | * @end: the offset 'to' which to invalidate (inclusive) | |
322 | * | |
323 | * This function only removes the unlocked pages, if you want to | |
324 | * remove all the pages of one inode, you must call truncate_inode_pages. | |
325 | * | |
326 | * invalidate_mapping_pages() will not block on IO activity. It will not | |
327 | * invalidate pages which are dirty, locked, under writeback or mapped into | |
328 | * pagetables. | |
329 | */ | |
330 | unsigned long invalidate_mapping_pages(struct address_space *mapping, | |
331 | pgoff_t start, pgoff_t end) | |
332 | { | |
333 | return __invalidate_mapping_pages(mapping, start, end, false); | |
334 | } | |
54bc4855 | 335 | EXPORT_SYMBOL(invalidate_mapping_pages); |
1da177e4 | 336 | |
bd4c8ce4 AM |
337 | /* |
338 | * This is like invalidate_complete_page(), except it ignores the page's | |
339 | * refcount. We do this because invalidate_inode_pages2() needs stronger | |
340 | * invalidation guarantees, and cannot afford to leave pages behind because | |
2706a1b8 AB |
341 | * shrink_page_list() has a temp ref on them, or because they're transiently |
342 | * sitting in the lru_cache_add() pagevecs. | |
bd4c8ce4 AM |
343 | */ |
344 | static int | |
345 | invalidate_complete_page2(struct address_space *mapping, struct page *page) | |
346 | { | |
347 | if (page->mapping != mapping) | |
348 | return 0; | |
349 | ||
887ed2f3 | 350 | if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL)) |
bd4c8ce4 AM |
351 | return 0; |
352 | ||
353 | write_lock_irq(&mapping->tree_lock); | |
354 | if (PageDirty(page)) | |
355 | goto failed; | |
356 | ||
357 | BUG_ON(PagePrivate(page)); | |
358 | __remove_from_page_cache(page); | |
359 | write_unlock_irq(&mapping->tree_lock); | |
360 | ClearPageUptodate(page); | |
361 | page_cache_release(page); /* pagecache ref */ | |
362 | return 1; | |
363 | failed: | |
364 | write_unlock_irq(&mapping->tree_lock); | |
365 | return 0; | |
366 | } | |
367 | ||
e3db7691 TM |
368 | static int do_launder_page(struct address_space *mapping, struct page *page) |
369 | { | |
370 | if (!PageDirty(page)) | |
371 | return 0; | |
372 | if (page->mapping != mapping || mapping->a_ops->launder_page == NULL) | |
373 | return 0; | |
374 | return mapping->a_ops->launder_page(page); | |
375 | } | |
376 | ||
1da177e4 LT |
377 | /** |
378 | * invalidate_inode_pages2_range - remove range of pages from an address_space | |
67be2dd1 | 379 | * @mapping: the address_space |
1da177e4 LT |
380 | * @start: the page offset 'from' which to invalidate |
381 | * @end: the page offset 'to' which to invalidate (inclusive) | |
382 | * | |
383 | * Any pages which are found to be mapped into pagetables are unmapped prior to | |
384 | * invalidation. | |
385 | * | |
386 | * Returns -EIO if any pages could not be invalidated. | |
387 | */ | |
388 | int invalidate_inode_pages2_range(struct address_space *mapping, | |
389 | pgoff_t start, pgoff_t end) | |
390 | { | |
391 | struct pagevec pvec; | |
392 | pgoff_t next; | |
393 | int i; | |
394 | int ret = 0; | |
395 | int did_range_unmap = 0; | |
396 | int wrapped = 0; | |
397 | ||
398 | pagevec_init(&pvec, 0); | |
399 | next = start; | |
7b965e08 | 400 | while (next <= end && !wrapped && |
1da177e4 LT |
401 | pagevec_lookup(&pvec, mapping, next, |
402 | min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) { | |
7b965e08 | 403 | for (i = 0; i < pagevec_count(&pvec); i++) { |
1da177e4 LT |
404 | struct page *page = pvec.pages[i]; |
405 | pgoff_t page_index; | |
1da177e4 LT |
406 | |
407 | lock_page(page); | |
408 | if (page->mapping != mapping) { | |
409 | unlock_page(page); | |
410 | continue; | |
411 | } | |
412 | page_index = page->index; | |
413 | next = page_index + 1; | |
414 | if (next == 0) | |
415 | wrapped = 1; | |
416 | if (page_index > end) { | |
417 | unlock_page(page); | |
418 | break; | |
419 | } | |
420 | wait_on_page_writeback(page); | |
d00806b1 | 421 | if (page_mapped(page)) { |
1da177e4 LT |
422 | if (!did_range_unmap) { |
423 | /* | |
424 | * Zap the rest of the file in one hit. | |
425 | */ | |
426 | unmap_mapping_range(mapping, | |
479ef592 OD |
427 | (loff_t)page_index<<PAGE_CACHE_SHIFT, |
428 | (loff_t)(end - page_index + 1) | |
1da177e4 LT |
429 | << PAGE_CACHE_SHIFT, |
430 | 0); | |
431 | did_range_unmap = 1; | |
432 | } else { | |
433 | /* | |
434 | * Just zap this page | |
435 | */ | |
436 | unmap_mapping_range(mapping, | |
479ef592 | 437 | (loff_t)page_index<<PAGE_CACHE_SHIFT, |
1da177e4 LT |
438 | PAGE_CACHE_SIZE, 0); |
439 | } | |
440 | } | |
d00806b1 | 441 | BUG_ON(page_mapped(page)); |
e3db7691 TM |
442 | ret = do_launder_page(mapping, page); |
443 | if (ret == 0 && !invalidate_complete_page2(mapping, page)) | |
1da177e4 | 444 | ret = -EIO; |
1da177e4 LT |
445 | unlock_page(page); |
446 | } | |
447 | pagevec_release(&pvec); | |
448 | cond_resched(); | |
449 | } | |
450 | return ret; | |
451 | } | |
452 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range); | |
453 | ||
454 | /** | |
455 | * invalidate_inode_pages2 - remove all pages from an address_space | |
67be2dd1 | 456 | * @mapping: the address_space |
1da177e4 LT |
457 | * |
458 | * Any pages which are found to be mapped into pagetables are unmapped prior to | |
459 | * invalidation. | |
460 | * | |
461 | * Returns -EIO if any pages could not be invalidated. | |
462 | */ | |
463 | int invalidate_inode_pages2(struct address_space *mapping) | |
464 | { | |
465 | return invalidate_inode_pages2_range(mapping, 0, -1); | |
466 | } | |
467 | EXPORT_SYMBOL_GPL(invalidate_inode_pages2); |