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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/truncate.c - code for taking down pages from address_spaces
3 *
4 * Copyright (C) 2002, Linus Torvalds
5 *
Francois Camie1f8e872008-10-15 22:01:59 -07006 * 10Sep2002 Andrew Morton
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * Initial version.
8 */
9
10#include <linux/kernel.h>
Alexey Dobriyan4af3c9c2007-10-16 23:29:23 -070011#include <linux/backing-dev.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/mm.h>
Nick Piggin0fd0e6b2006-09-27 01:50:02 -070013#include <linux/swap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/module.h>
15#include <linux/pagemap.h>
Nate Diller01f2705d2007-05-09 02:35:07 -070016#include <linux/highmem.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/pagevec.h>
Andrew Mortone08748ce2006-12-10 02:19:31 -080018#include <linux/task_io_accounting_ops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/buffer_head.h> /* grr. try_to_release_page,
Jan Karaaaa40592005-10-30 15:00:16 -080020 do_invalidatepage */
Rik van Rielba470de2008-10-18 20:26:50 -070021#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
23
David Howellscf9a2ae2006-08-29 19:05:54 +010024/**
Fengguang Wu28bc44d2008-02-03 18:04:10 +020025 * do_invalidatepage - invalidate part or all of a page
David Howellscf9a2ae2006-08-29 19:05:54 +010026 * @page: the page which is affected
27 * @offset: the index of the truncation point
28 *
29 * do_invalidatepage() is called when all or part of the page has become
30 * invalidated by a truncate operation.
31 *
32 * do_invalidatepage() does not have to release all buffers, but it must
33 * ensure that no dirty buffer is left outside @offset and that no I/O
34 * is underway against any of the blocks which are outside the truncation
35 * point. Because the caller is about to free (and possibly reuse) those
36 * blocks on-disk.
37 */
38void do_invalidatepage(struct page *page, unsigned long offset)
39{
40 void (*invalidatepage)(struct page *, unsigned long);
41 invalidatepage = page->mapping->a_ops->invalidatepage;
David Howells93614012006-09-30 20:45:40 +020042#ifdef CONFIG_BLOCK
David Howellscf9a2ae2006-08-29 19:05:54 +010043 if (!invalidatepage)
44 invalidatepage = block_invalidatepage;
David Howells93614012006-09-30 20:45:40 +020045#endif
David Howellscf9a2ae2006-08-29 19:05:54 +010046 if (invalidatepage)
47 (*invalidatepage)(page, offset);
48}
49
Linus Torvalds1da177e2005-04-16 15:20:36 -070050static inline void truncate_partial_page(struct page *page, unsigned partial)
51{
Christoph Lametereebd2aa2008-02-04 22:28:29 -080052 zero_user_segment(page, partial, PAGE_CACHE_SIZE);
David Howells266cf652009-04-03 16:42:36 +010053 if (page_has_private(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 do_invalidatepage(page, partial);
55}
56
Linus Torvaldsecdfc972007-01-26 12:47:06 -080057/*
58 * This cancels just the dirty bit on the kernel page itself, it
59 * does NOT actually remove dirty bits on any mmap's that may be
60 * around. It also leaves the page tagged dirty, so any sync
61 * activity will still find it on the dirty lists, and in particular,
62 * clear_page_dirty_for_io() will still look at the dirty bits in
63 * the VM.
64 *
65 * Doing this should *normally* only ever be done when a page
66 * is truncated, and is not actually mapped anywhere at all. However,
67 * fs/buffer.c does this when it notices that somebody has cleaned
68 * out all the buffers on a page without actually doing it through
69 * the VM. Can you say "ext3 is horribly ugly"? Tought you could.
70 */
Linus Torvaldsfba25912006-12-20 13:46:42 -080071void cancel_dirty_page(struct page *page, unsigned int account_size)
72{
Linus Torvalds8368e322006-12-23 09:25:04 -080073 if (TestClearPageDirty(page)) {
74 struct address_space *mapping = page->mapping;
75 if (mapping && mapping_cap_account_dirty(mapping)) {
76 dec_zone_page_state(page, NR_FILE_DIRTY);
Peter Zijlstrac9e51e42007-10-16 23:25:47 -070077 dec_bdi_stat(mapping->backing_dev_info,
78 BDI_RECLAIMABLE);
Linus Torvalds8368e322006-12-23 09:25:04 -080079 if (account_size)
80 task_io_account_cancelled_write(account_size);
81 }
Andrew Morton3e67c092006-12-21 11:00:33 -080082 }
Linus Torvaldsfba25912006-12-20 13:46:42 -080083}
Linus Torvalds8368e322006-12-23 09:25:04 -080084EXPORT_SYMBOL(cancel_dirty_page);
Linus Torvaldsfba25912006-12-20 13:46:42 -080085
Linus Torvalds1da177e2005-04-16 15:20:36 -070086/*
87 * If truncate cannot remove the fs-private metadata from the page, the page
Shaohua Li62e1c552008-02-04 22:29:33 -080088 * becomes orphaned. It will be left on the LRU and may even be mapped into
Nick Piggin54cb8822007-07-19 01:46:59 -070089 * user pagetables if we're racing with filemap_fault().
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 *
91 * We need to bale out if page->mapping is no longer equal to the original
92 * mapping. This happens a) when the VM reclaimed the page while we waited on
Andrew Mortonfc0ecff2007-02-10 01:45:39 -080093 * its lock, b) when a concurrent invalidate_mapping_pages got there first and
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
95 */
Nick Piggin750b4982009-09-16 11:50:12 +020096static int
Linus Torvalds1da177e2005-04-16 15:20:36 -070097truncate_complete_page(struct address_space *mapping, struct page *page)
98{
99 if (page->mapping != mapping)
Nick Piggin750b4982009-09-16 11:50:12 +0200100 return -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
David Howells266cf652009-04-03 16:42:36 +0100102 if (page_has_private(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 do_invalidatepage(page, 0);
104
Bjorn Steinbrinka2b34562008-02-04 22:29:28 -0800105 cancel_dirty_page(page, PAGE_CACHE_SIZE);
106
Rik van Rielba470de2008-10-18 20:26:50 -0700107 clear_page_mlock(page);
Nick Piggin787d22142007-07-17 04:03:34 -0700108 remove_from_page_cache(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 ClearPageMappedToDisk(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 page_cache_release(page); /* pagecache ref */
Nick Piggin750b4982009-09-16 11:50:12 +0200111 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112}
113
114/*
Andrew Mortonfc0ecff2007-02-10 01:45:39 -0800115 * This is for invalidate_mapping_pages(). That function can be called at
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 * any time, and is not supposed to throw away dirty pages. But pages can
Nick Piggin0fd0e6b2006-09-27 01:50:02 -0700117 * be marked dirty at any time too, so use remove_mapping which safely
118 * discards clean, unused pages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 *
120 * Returns non-zero if the page was successfully invalidated.
121 */
122static int
123invalidate_complete_page(struct address_space *mapping, struct page *page)
124{
Nick Piggin0fd0e6b2006-09-27 01:50:02 -0700125 int ret;
126
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 if (page->mapping != mapping)
128 return 0;
129
David Howells266cf652009-04-03 16:42:36 +0100130 if (page_has_private(page) && !try_to_release_page(page, 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 return 0;
132
Rik van Rielba470de2008-10-18 20:26:50 -0700133 clear_page_mlock(page);
Nick Piggin0fd0e6b2006-09-27 01:50:02 -0700134 ret = remove_mapping(mapping, page);
Nick Piggin0fd0e6b2006-09-27 01:50:02 -0700135
136 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137}
138
Nick Piggin750b4982009-09-16 11:50:12 +0200139int truncate_inode_page(struct address_space *mapping, struct page *page)
140{
141 if (page_mapped(page)) {
142 unmap_mapping_range(mapping,
143 (loff_t)page->index << PAGE_CACHE_SHIFT,
144 PAGE_CACHE_SIZE, 0);
145 }
146 return truncate_complete_page(mapping, page);
147}
148
Wu Fengguang83f78662009-09-16 11:50:13 +0200149/*
Andi Kleen25718732009-09-16 11:50:13 +0200150 * Used to get rid of pages on hardware memory corruption.
151 */
152int generic_error_remove_page(struct address_space *mapping, struct page *page)
153{
154 if (!mapping)
155 return -EINVAL;
156 /*
157 * Only punch for normal data pages for now.
158 * Handling other types like directories would need more auditing.
159 */
160 if (!S_ISREG(mapping->host->i_mode))
161 return -EIO;
162 return truncate_inode_page(mapping, page);
163}
164EXPORT_SYMBOL(generic_error_remove_page);
165
166/*
Wu Fengguang83f78662009-09-16 11:50:13 +0200167 * Safely invalidate one page from its pagecache mapping.
168 * It only drops clean, unused pages. The page must be locked.
169 *
170 * Returns 1 if the page is successfully invalidated, otherwise 0.
171 */
172int invalidate_inode_page(struct page *page)
173{
174 struct address_space *mapping = page_mapping(page);
175 if (!mapping)
176 return 0;
177 if (PageDirty(page) || PageWriteback(page))
178 return 0;
179 if (page_mapped(page))
180 return 0;
181 return invalidate_complete_page(mapping, page);
182}
183
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184/**
Randy Dunlap06432452008-02-29 22:03:15 -0800185 * truncate_inode_pages - truncate range of pages specified by start & end byte offsets
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 * @mapping: mapping to truncate
187 * @lstart: offset from which to truncate
Hans Reiserd7339072006-01-06 00:10:36 -0800188 * @lend: offset to which to truncate
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 *
Hans Reiserd7339072006-01-06 00:10:36 -0800190 * Truncate the page cache, removing the pages that are between
191 * specified offsets (and zeroing out partial page
192 * (if lstart is not page aligned)).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 *
194 * Truncate takes two passes - the first pass is nonblocking. It will not
195 * block on page locks and it will not block on writeback. The second pass
196 * will wait. This is to prevent as much IO as possible in the affected region.
197 * The first pass will remove most pages, so the search cost of the second pass
198 * is low.
199 *
200 * When looking at page->index outside the page lock we need to be careful to
201 * copy it into a local to avoid races (it could change at any time).
202 *
203 * We pass down the cache-hot hint to the page freeing code. Even if the
204 * mapping is large, it is probably the case that the final pages are the most
205 * recently touched, and freeing happens in ascending file offset order.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 */
Hans Reiserd7339072006-01-06 00:10:36 -0800207void truncate_inode_pages_range(struct address_space *mapping,
208 loff_t lstart, loff_t lend)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209{
210 const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
Hans Reiserd7339072006-01-06 00:10:36 -0800211 pgoff_t end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
213 struct pagevec pvec;
214 pgoff_t next;
215 int i;
216
217 if (mapping->nrpages == 0)
218 return;
219
Hans Reiserd7339072006-01-06 00:10:36 -0800220 BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1));
221 end = (lend >> PAGE_CACHE_SHIFT);
222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 pagevec_init(&pvec, 0);
224 next = start;
Hans Reiserd7339072006-01-06 00:10:36 -0800225 while (next <= end &&
226 pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 for (i = 0; i < pagevec_count(&pvec); i++) {
228 struct page *page = pvec.pages[i];
229 pgoff_t page_index = page->index;
230
Hans Reiserd7339072006-01-06 00:10:36 -0800231 if (page_index > end) {
232 next = page_index;
233 break;
234 }
235
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 if (page_index > next)
237 next = page_index;
238 next++;
Nick Piggin529ae9a2008-08-02 12:01:03 +0200239 if (!trylock_page(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 continue;
241 if (PageWriteback(page)) {
242 unlock_page(page);
243 continue;
244 }
Nick Piggin750b4982009-09-16 11:50:12 +0200245 truncate_inode_page(mapping, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 unlock_page(page);
247 }
248 pagevec_release(&pvec);
249 cond_resched();
250 }
251
252 if (partial) {
253 struct page *page = find_lock_page(mapping, start - 1);
254 if (page) {
255 wait_on_page_writeback(page);
256 truncate_partial_page(page, partial);
257 unlock_page(page);
258 page_cache_release(page);
259 }
260 }
261
262 next = start;
263 for ( ; ; ) {
264 cond_resched();
265 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
266 if (next == start)
267 break;
268 next = start;
269 continue;
270 }
Hans Reiserd7339072006-01-06 00:10:36 -0800271 if (pvec.pages[0]->index > end) {
272 pagevec_release(&pvec);
273 break;
274 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 for (i = 0; i < pagevec_count(&pvec); i++) {
276 struct page *page = pvec.pages[i];
277
Hans Reiserd7339072006-01-06 00:10:36 -0800278 if (page->index > end)
279 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 lock_page(page);
281 wait_on_page_writeback(page);
Nick Piggin750b4982009-09-16 11:50:12 +0200282 truncate_inode_page(mapping, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 if (page->index > next)
284 next = page->index;
285 next++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 unlock_page(page);
287 }
288 pagevec_release(&pvec);
289 }
290}
Hans Reiserd7339072006-01-06 00:10:36 -0800291EXPORT_SYMBOL(truncate_inode_pages_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292
Hans Reiserd7339072006-01-06 00:10:36 -0800293/**
294 * truncate_inode_pages - truncate *all* the pages from an offset
295 * @mapping: mapping to truncate
296 * @lstart: offset from which to truncate
297 *
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800298 * Called under (and serialised by) inode->i_mutex.
Hans Reiserd7339072006-01-06 00:10:36 -0800299 */
300void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
301{
302 truncate_inode_pages_range(mapping, lstart, (loff_t)-1);
303}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304EXPORT_SYMBOL(truncate_inode_pages);
305
Mike Waychison28697352009-06-16 15:32:59 -0700306/**
307 * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
308 * @mapping: the address_space which holds the pages to invalidate
309 * @start: the offset 'from' which to invalidate
310 * @end: the offset 'to' which to invalidate (inclusive)
311 *
312 * This function only removes the unlocked pages, if you want to
313 * remove all the pages of one inode, you must call truncate_inode_pages.
314 *
315 * invalidate_mapping_pages() will not block on IO activity. It will not
316 * invalidate pages which are dirty, locked, under writeback or mapped into
317 * pagetables.
318 */
319unsigned long invalidate_mapping_pages(struct address_space *mapping,
320 pgoff_t start, pgoff_t end)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321{
322 struct pagevec pvec;
323 pgoff_t next = start;
324 unsigned long ret = 0;
325 int i;
326
327 pagevec_init(&pvec, 0);
328 while (next <= end &&
329 pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
330 for (i = 0; i < pagevec_count(&pvec); i++) {
331 struct page *page = pvec.pages[i];
NeilBrowne0f236032006-06-23 02:05:48 -0700332 pgoff_t index;
333 int lock_failed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334
Nick Piggin529ae9a2008-08-02 12:01:03 +0200335 lock_failed = !trylock_page(page);
NeilBrowne0f236032006-06-23 02:05:48 -0700336
337 /*
338 * We really shouldn't be looking at the ->index of an
339 * unlocked page. But we're not allowed to lock these
340 * pages. So we rely upon nobody altering the ->index
341 * of this (pinned-by-us) page.
342 */
343 index = page->index;
344 if (index > next)
345 next = index;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 next++;
NeilBrowne0f236032006-06-23 02:05:48 -0700347 if (lock_failed)
348 continue;
349
Wu Fengguang83f78662009-09-16 11:50:13 +0200350 ret += invalidate_inode_page(page);
351
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 unlock_page(page);
353 if (next > end)
354 break;
355 }
356 pagevec_release(&pvec);
Mike Waychison28697352009-06-16 15:32:59 -0700357 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 }
359 return ret;
360}
Anton Altaparmakov54bc4852007-02-10 01:45:38 -0800361EXPORT_SYMBOL(invalidate_mapping_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700363/*
364 * This is like invalidate_complete_page(), except it ignores the page's
365 * refcount. We do this because invalidate_inode_pages2() needs stronger
366 * invalidation guarantees, and cannot afford to leave pages behind because
Anderson Briglia2706a1b2007-07-15 23:38:09 -0700367 * shrink_page_list() has a temp ref on them, or because they're transiently
368 * sitting in the lru_cache_add() pagevecs.
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700369 */
370static int
371invalidate_complete_page2(struct address_space *mapping, struct page *page)
372{
373 if (page->mapping != mapping)
374 return 0;
375
David Howells266cf652009-04-03 16:42:36 +0100376 if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700377 return 0;
378
Nick Piggin19fd6232008-07-25 19:45:32 -0700379 spin_lock_irq(&mapping->tree_lock);
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700380 if (PageDirty(page))
381 goto failed;
382
Rik van Rielba470de2008-10-18 20:26:50 -0700383 clear_page_mlock(page);
David Howells266cf652009-04-03 16:42:36 +0100384 BUG_ON(page_has_private(page));
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700385 __remove_from_page_cache(page);
Nick Piggin19fd6232008-07-25 19:45:32 -0700386 spin_unlock_irq(&mapping->tree_lock);
Daisuke Nishimurae767e052009-05-28 14:34:28 -0700387 mem_cgroup_uncharge_cache_page(page);
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700388 page_cache_release(page); /* pagecache ref */
389 return 1;
390failed:
Nick Piggin19fd6232008-07-25 19:45:32 -0700391 spin_unlock_irq(&mapping->tree_lock);
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700392 return 0;
393}
394
Trond Myklebuste3db7692007-01-10 23:15:39 -0800395static int do_launder_page(struct address_space *mapping, struct page *page)
396{
397 if (!PageDirty(page))
398 return 0;
399 if (page->mapping != mapping || mapping->a_ops->launder_page == NULL)
400 return 0;
401 return mapping->a_ops->launder_page(page);
402}
403
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404/**
405 * invalidate_inode_pages2_range - remove range of pages from an address_space
Martin Waitz67be2dd2005-05-01 08:59:26 -0700406 * @mapping: the address_space
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 * @start: the page offset 'from' which to invalidate
408 * @end: the page offset 'to' which to invalidate (inclusive)
409 *
410 * Any pages which are found to be mapped into pagetables are unmapped prior to
411 * invalidation.
412 *
Hisashi Hifumi6ccfa802008-09-02 14:35:40 -0700413 * Returns -EBUSY if any pages could not be invalidated.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 */
415int invalidate_inode_pages2_range(struct address_space *mapping,
416 pgoff_t start, pgoff_t end)
417{
418 struct pagevec pvec;
419 pgoff_t next;
420 int i;
421 int ret = 0;
Hisashi Hifumi0dd13342008-04-28 02:12:08 -0700422 int ret2 = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 int did_range_unmap = 0;
424 int wrapped = 0;
425
426 pagevec_init(&pvec, 0);
427 next = start;
Trond Myklebust7b965e02007-02-28 20:13:55 -0800428 while (next <= end && !wrapped &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 pagevec_lookup(&pvec, mapping, next,
430 min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
Trond Myklebust7b965e02007-02-28 20:13:55 -0800431 for (i = 0; i < pagevec_count(&pvec); i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 struct page *page = pvec.pages[i];
433 pgoff_t page_index;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434
435 lock_page(page);
436 if (page->mapping != mapping) {
437 unlock_page(page);
438 continue;
439 }
440 page_index = page->index;
441 next = page_index + 1;
442 if (next == 0)
443 wrapped = 1;
444 if (page_index > end) {
445 unlock_page(page);
446 break;
447 }
448 wait_on_page_writeback(page);
Nick Piggind00806b2007-07-19 01:46:57 -0700449 if (page_mapped(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 if (!did_range_unmap) {
451 /*
452 * Zap the rest of the file in one hit.
453 */
454 unmap_mapping_range(mapping,
Oleg Drokin479ef592005-11-23 13:37:47 -0800455 (loff_t)page_index<<PAGE_CACHE_SHIFT,
456 (loff_t)(end - page_index + 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 << PAGE_CACHE_SHIFT,
458 0);
459 did_range_unmap = 1;
460 } else {
461 /*
462 * Just zap this page
463 */
464 unmap_mapping_range(mapping,
Oleg Drokin479ef592005-11-23 13:37:47 -0800465 (loff_t)page_index<<PAGE_CACHE_SHIFT,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 PAGE_CACHE_SIZE, 0);
467 }
468 }
Nick Piggind00806b2007-07-19 01:46:57 -0700469 BUG_ON(page_mapped(page));
Hisashi Hifumi0dd13342008-04-28 02:12:08 -0700470 ret2 = do_launder_page(mapping, page);
471 if (ret2 == 0) {
472 if (!invalidate_complete_page2(mapping, page))
Hisashi Hifumi6ccfa802008-09-02 14:35:40 -0700473 ret2 = -EBUSY;
Hisashi Hifumi0dd13342008-04-28 02:12:08 -0700474 }
475 if (ret2 < 0)
476 ret = ret2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 unlock_page(page);
478 }
479 pagevec_release(&pvec);
480 cond_resched();
481 }
482 return ret;
483}
484EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
485
486/**
487 * invalidate_inode_pages2 - remove all pages from an address_space
Martin Waitz67be2dd2005-05-01 08:59:26 -0700488 * @mapping: the address_space
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 *
490 * Any pages which are found to be mapped into pagetables are unmapped prior to
491 * invalidation.
492 *
Peng Taoe9de25d2009-10-19 14:48:13 +0800493 * Returns -EBUSY if any pages could not be invalidated.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 */
495int invalidate_inode_pages2(struct address_space *mapping)
496{
497 return invalidate_inode_pages2_range(mapping, 0, -1);
498}
499EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +1000500
501/**
502 * truncate_pagecache - unmap and remove pagecache that has been truncated
503 * @inode: inode
504 * @old: old file offset
505 * @new: new file offset
506 *
507 * inode's new i_size must already be written before truncate_pagecache
508 * is called.
509 *
510 * This function should typically be called before the filesystem
511 * releases resources associated with the freed range (eg. deallocates
512 * blocks). This way, pagecache will always stay logically coherent
513 * with on-disk format, and the filesystem would not have to deal with
514 * situations such as writepage being called for a page that has already
515 * had its underlying blocks deallocated.
516 */
517void truncate_pagecache(struct inode *inode, loff_t old, loff_t new)
518{
519 if (new < old) {
520 struct address_space *mapping = inode->i_mapping;
521
522 /*
523 * unmap_mapping_range is called twice, first simply for
524 * efficiency so that truncate_inode_pages does fewer
525 * single-page unmaps. However after this first call, and
526 * before truncate_inode_pages finishes, it is possible for
527 * private pages to be COWed, which remain after
528 * truncate_inode_pages finishes, hence the second
529 * unmap_mapping_range call must be made for correctness.
530 */
531 unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
532 truncate_inode_pages(mapping, new);
533 unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
534 }
535}
536EXPORT_SYMBOL(truncate_pagecache);
537
538/**
539 * vmtruncate - unmap mappings "freed" by truncate() syscall
540 * @inode: inode of the file used
541 * @offset: file offset to start truncating
542 *
543 * NOTE! We have to be ready to update the memory sharing
544 * between the file and the memory map for a potential last
545 * incomplete page. Ugly, but necessary.
546 */
547int vmtruncate(struct inode *inode, loff_t offset)
548{
549 loff_t oldsize;
550 int error;
551
552 error = inode_newsize_ok(inode, offset);
553 if (error)
554 return error;
555 oldsize = inode->i_size;
556 i_size_write(inode, offset);
557 truncate_pagecache(inode, oldsize, offset);
558 if (inode->i_op->truncate)
559 inode->i_op->truncate(inode);
560
561 return error;
562}
563EXPORT_SYMBOL(vmtruncate);