blob: 9c809e7d73c3635c9263fd34fcce4a90e1903808 [file] [log] [blame]
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>
Ross Zwislerf9fe48b2016-01-22 15:10:40 -080012#include <linux/dax.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090013#include <linux/gfp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/mm.h>
Nick Piggin0fd0e6b2006-09-27 01:50:02 -070015#include <linux/swap.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040016#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/pagemap.h>
Nate Diller01f27052007-05-09 02:35:07 -070018#include <linux/highmem.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/pagevec.h>
Andrew Mortone08748ce2006-12-10 02:19:31 -080020#include <linux/task_io_accounting_ops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/buffer_head.h> /* grr. try_to_release_page,
Jan Karaaaa40592005-10-30 15:00:16 -080022 do_invalidatepage */
Dan Magenheimerc515e1f2011-05-26 10:01:43 -060023#include <linux/cleancache.h>
Jan Kara90a80202014-10-01 21:49:18 -040024#include <linux/rmap.h>
Rik van Rielba470de2008-10-18 20:26:50 -070025#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070026
Johannes Weiner0cd61442014-04-03 14:47:46 -070027static void clear_exceptional_entry(struct address_space *mapping,
28 pgoff_t index, void *entry)
29{
Johannes Weiner449dd692014-04-03 14:47:56 -070030 struct radix_tree_node *node;
31 void **slot;
32
Johannes Weiner0cd61442014-04-03 14:47:46 -070033 /* Handled by shmem itself */
34 if (shmem_mapping(mapping))
35 return;
36
Ross Zwislerf9fe48b2016-01-22 15:10:40 -080037 if (dax_mapping(mapping)) {
Jan Karaac401cc2016-05-12 18:29:18 +020038 dax_delete_mapping_entry(mapping, index);
39 return;
Ross Zwislerf9fe48b2016-01-22 15:10:40 -080040 }
Jan Karaac401cc2016-05-12 18:29:18 +020041 spin_lock_irq(&mapping->tree_lock);
42 /*
43 * Regular page slots are stabilized by the page lock even
44 * without the tree itself locked. These unlocked entries
45 * need verification under the tree lock.
46 */
47 if (!__radix_tree_lookup(&mapping->page_tree, index, &node,
48 &slot))
49 goto unlock;
50 if (*slot != entry)
51 goto unlock;
52 radix_tree_replace_slot(slot, NULL);
53 mapping->nrexceptional--;
54 if (!node)
55 goto unlock;
56 workingset_node_shadows_dec(node);
57 /*
58 * Don't track node without shadow entries.
59 *
60 * Avoid acquiring the list_lru lock if already untracked.
61 * The list_empty() test is safe as node->private_list is
62 * protected by mapping->tree_lock.
63 */
64 if (!workingset_node_shadows(node) &&
65 !list_empty(&node->private_list))
66 list_lru_del(&workingset_shadow_nodes,
67 &node->private_list);
68 __radix_tree_delete_node(&mapping->page_tree, node);
Johannes Weiner449dd692014-04-03 14:47:56 -070069unlock:
Johannes Weiner0cd61442014-04-03 14:47:46 -070070 spin_unlock_irq(&mapping->tree_lock);
71}
Linus Torvalds1da177e2005-04-16 15:20:36 -070072
David Howellscf9a2ae2006-08-29 19:05:54 +010073/**
Fengguang Wu28bc44d2008-02-03 18:04:10 +020074 * do_invalidatepage - invalidate part or all of a page
David Howellscf9a2ae2006-08-29 19:05:54 +010075 * @page: the page which is affected
Lukas Czernerd47992f2013-05-21 23:17:23 -040076 * @offset: start of the range to invalidate
77 * @length: length of the range to invalidate
David Howellscf9a2ae2006-08-29 19:05:54 +010078 *
79 * do_invalidatepage() is called when all or part of the page has become
80 * invalidated by a truncate operation.
81 *
82 * do_invalidatepage() does not have to release all buffers, but it must
83 * ensure that no dirty buffer is left outside @offset and that no I/O
84 * is underway against any of the blocks which are outside the truncation
85 * point. Because the caller is about to free (and possibly reuse) those
86 * blocks on-disk.
87 */
Lukas Czernerd47992f2013-05-21 23:17:23 -040088void do_invalidatepage(struct page *page, unsigned int offset,
89 unsigned int length)
David Howellscf9a2ae2006-08-29 19:05:54 +010090{
Lukas Czernerd47992f2013-05-21 23:17:23 -040091 void (*invalidatepage)(struct page *, unsigned int, unsigned int);
92
David Howellscf9a2ae2006-08-29 19:05:54 +010093 invalidatepage = page->mapping->a_ops->invalidatepage;
David Howells93614012006-09-30 20:45:40 +020094#ifdef CONFIG_BLOCK
David Howellscf9a2ae2006-08-29 19:05:54 +010095 if (!invalidatepage)
96 invalidatepage = block_invalidatepage;
David Howells93614012006-09-30 20:45:40 +020097#endif
David Howellscf9a2ae2006-08-29 19:05:54 +010098 if (invalidatepage)
Lukas Czernerd47992f2013-05-21 23:17:23 -040099 (*invalidatepage)(page, offset, length);
David Howellscf9a2ae2006-08-29 19:05:54 +0100100}
101
Linus Torvaldsecdfc972007-01-26 12:47:06 -0800102/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 * If truncate cannot remove the fs-private metadata from the page, the page
Shaohua Li62e1c552008-02-04 22:29:33 -0800104 * becomes orphaned. It will be left on the LRU and may even be mapped into
Nick Piggin54cb8822007-07-19 01:46:59 -0700105 * user pagetables if we're racing with filemap_fault().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 *
107 * We need to bale out if page->mapping is no longer equal to the original
108 * mapping. This happens a) when the VM reclaimed the page while we waited on
Andrew Mortonfc0ecff2007-02-10 01:45:39 -0800109 * its lock, b) when a concurrent invalidate_mapping_pages got there first and
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
111 */
Nick Piggin750b4982009-09-16 11:50:12 +0200112static int
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113truncate_complete_page(struct address_space *mapping, struct page *page)
114{
115 if (page->mapping != mapping)
Nick Piggin750b4982009-09-16 11:50:12 +0200116 return -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
David Howells266cf652009-04-03 16:42:36 +0100118 if (page_has_private(page))
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300119 do_invalidatepage(page, 0, PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
Konstantin Khlebnikovb9ea2512015-04-14 15:45:27 -0700121 /*
122 * Some filesystems seem to re-dirty the page even after
123 * the VM has canceled the dirty bit (eg ext3 journaling).
124 * Hence dirty accounting check is placed after invalidation.
125 */
Tejun Heo11f81be2015-05-22 17:13:15 -0400126 cancel_dirty_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 ClearPageMappedToDisk(page);
Minchan Kim5adc7b52011-03-22 16:32:41 -0700128 delete_from_page_cache(page);
Nick Piggin750b4982009-09-16 11:50:12 +0200129 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130}
131
132/*
Andrew Mortonfc0ecff2007-02-10 01:45:39 -0800133 * This is for invalidate_mapping_pages(). That function can be called at
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 * any time, and is not supposed to throw away dirty pages. But pages can
Nick Piggin0fd0e6b2006-09-27 01:50:02 -0700135 * be marked dirty at any time too, so use remove_mapping which safely
136 * discards clean, unused pages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 *
138 * Returns non-zero if the page was successfully invalidated.
139 */
140static int
141invalidate_complete_page(struct address_space *mapping, struct page *page)
142{
Nick Piggin0fd0e6b2006-09-27 01:50:02 -0700143 int ret;
144
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 if (page->mapping != mapping)
146 return 0;
147
David Howells266cf652009-04-03 16:42:36 +0100148 if (page_has_private(page) && !try_to_release_page(page, 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 return 0;
150
Nick Piggin0fd0e6b2006-09-27 01:50:02 -0700151 ret = remove_mapping(mapping, page);
Nick Piggin0fd0e6b2006-09-27 01:50:02 -0700152
153 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154}
155
Nick Piggin750b4982009-09-16 11:50:12 +0200156int truncate_inode_page(struct address_space *mapping, struct page *page)
157{
Kirill A. Shutemovfc127da2016-07-26 15:26:07 -0700158 loff_t holelen;
159 VM_BUG_ON_PAGE(PageTail(page), page);
160
161 holelen = PageTransHuge(page) ? HPAGE_PMD_SIZE : PAGE_SIZE;
Nick Piggin750b4982009-09-16 11:50:12 +0200162 if (page_mapped(page)) {
163 unmap_mapping_range(mapping,
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300164 (loff_t)page->index << PAGE_SHIFT,
Kirill A. Shutemovfc127da2016-07-26 15:26:07 -0700165 holelen, 0);
Nick Piggin750b4982009-09-16 11:50:12 +0200166 }
167 return truncate_complete_page(mapping, page);
168}
169
Wu Fengguang83f78662009-09-16 11:50:13 +0200170/*
Andi Kleen25718732009-09-16 11:50:13 +0200171 * Used to get rid of pages on hardware memory corruption.
172 */
173int generic_error_remove_page(struct address_space *mapping, struct page *page)
174{
175 if (!mapping)
176 return -EINVAL;
177 /*
178 * Only punch for normal data pages for now.
179 * Handling other types like directories would need more auditing.
180 */
181 if (!S_ISREG(mapping->host->i_mode))
182 return -EIO;
183 return truncate_inode_page(mapping, page);
184}
185EXPORT_SYMBOL(generic_error_remove_page);
186
187/*
Wu Fengguang83f78662009-09-16 11:50:13 +0200188 * Safely invalidate one page from its pagecache mapping.
189 * It only drops clean, unused pages. The page must be locked.
190 *
191 * Returns 1 if the page is successfully invalidated, otherwise 0.
192 */
193int invalidate_inode_page(struct page *page)
194{
195 struct address_space *mapping = page_mapping(page);
196 if (!mapping)
197 return 0;
198 if (PageDirty(page) || PageWriteback(page))
199 return 0;
200 if (page_mapped(page))
201 return 0;
202 return invalidate_complete_page(mapping, page);
203}
204
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205/**
Liu Bo73c1e202012-02-21 10:57:20 +0800206 * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 * @mapping: mapping to truncate
208 * @lstart: offset from which to truncate
Lukas Czerner5a720392013-05-27 23:32:35 -0400209 * @lend: offset to which to truncate (inclusive)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 *
Hans Reiserd7339072006-01-06 00:10:36 -0800211 * Truncate the page cache, removing the pages that are between
Lukas Czerner5a720392013-05-27 23:32:35 -0400212 * specified offsets (and zeroing out partial pages
213 * if lstart or lend + 1 is not page aligned).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 *
215 * Truncate takes two passes - the first pass is nonblocking. It will not
216 * block on page locks and it will not block on writeback. The second pass
217 * will wait. This is to prevent as much IO as possible in the affected region.
218 * The first pass will remove most pages, so the search cost of the second pass
219 * is low.
220 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 * We pass down the cache-hot hint to the page freeing code. Even if the
222 * mapping is large, it is probably the case that the final pages are the most
223 * recently touched, and freeing happens in ascending file offset order.
Lukas Czerner5a720392013-05-27 23:32:35 -0400224 *
225 * Note that since ->invalidatepage() accepts range to invalidate
226 * truncate_inode_pages_range is able to handle cases where lend + 1 is not
227 * page aligned properly.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 */
Hans Reiserd7339072006-01-06 00:10:36 -0800229void truncate_inode_pages_range(struct address_space *mapping,
230 loff_t lstart, loff_t lend)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231{
Lukas Czerner5a720392013-05-27 23:32:35 -0400232 pgoff_t start; /* inclusive */
233 pgoff_t end; /* exclusive */
234 unsigned int partial_start; /* inclusive */
235 unsigned int partial_end; /* exclusive */
236 struct pagevec pvec;
Johannes Weiner0cd61442014-04-03 14:47:46 -0700237 pgoff_t indices[PAGEVEC_SIZE];
Lukas Czerner5a720392013-05-27 23:32:35 -0400238 pgoff_t index;
239 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240
Dan Magenheimer31677602011-09-21 11:56:28 -0400241 cleancache_invalidate_inode(mapping);
Ross Zwislerf9fe48b2016-01-22 15:10:40 -0800242 if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 return;
244
Lukas Czerner5a720392013-05-27 23:32:35 -0400245 /* Offsets within partial pages */
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300246 partial_start = lstart & (PAGE_SIZE - 1);
247 partial_end = (lend + 1) & (PAGE_SIZE - 1);
Lukas Czerner5a720392013-05-27 23:32:35 -0400248
249 /*
250 * 'start' and 'end' always covers the range of pages to be fully
251 * truncated. Partial pages are covered with 'partial_start' at the
252 * start of the range and 'partial_end' at the end of the range.
253 * Note that 'end' is exclusive while 'lend' is inclusive.
254 */
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300255 start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
Lukas Czerner5a720392013-05-27 23:32:35 -0400256 if (lend == -1)
257 /*
258 * lend == -1 indicates end-of-file so we have to set 'end'
259 * to the highest possible pgoff_t and since the type is
260 * unsigned we're using -1.
261 */
262 end = -1;
263 else
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300264 end = (lend + 1) >> PAGE_SHIFT;
Hans Reiserd7339072006-01-06 00:10:36 -0800265
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 pagevec_init(&pvec, 0);
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700267 index = start;
Johannes Weiner0cd61442014-04-03 14:47:46 -0700268 while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
269 min(end - index, (pgoff_t)PAGEVEC_SIZE),
270 indices)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 for (i = 0; i < pagevec_count(&pvec); i++) {
272 struct page *page = pvec.pages[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700274 /* We rely upon deletion not changing page->index */
Johannes Weiner0cd61442014-04-03 14:47:46 -0700275 index = indices[i];
Lukas Czerner5a720392013-05-27 23:32:35 -0400276 if (index >= end)
Hans Reiserd7339072006-01-06 00:10:36 -0800277 break;
Hans Reiserd7339072006-01-06 00:10:36 -0800278
Johannes Weiner0cd61442014-04-03 14:47:46 -0700279 if (radix_tree_exceptional_entry(page)) {
280 clear_exceptional_entry(mapping, index, page);
281 continue;
282 }
283
Nick Piggin529ae9a2008-08-02 12:01:03 +0200284 if (!trylock_page(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 continue;
Kirill A. Shutemov5cbc1982016-11-30 15:54:19 -0800286 WARN_ON(page_to_index(page) != index);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 if (PageWriteback(page)) {
288 unlock_page(page);
289 continue;
290 }
Nick Piggin750b4982009-09-16 11:50:12 +0200291 truncate_inode_page(mapping, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 unlock_page(page);
293 }
Johannes Weiner0cd61442014-04-03 14:47:46 -0700294 pagevec_remove_exceptionals(&pvec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 pagevec_release(&pvec);
296 cond_resched();
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700297 index++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 }
299
Lukas Czerner5a720392013-05-27 23:32:35 -0400300 if (partial_start) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 struct page *page = find_lock_page(mapping, start - 1);
302 if (page) {
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300303 unsigned int top = PAGE_SIZE;
Lukas Czerner5a720392013-05-27 23:32:35 -0400304 if (start > end) {
305 /* Truncation within a single page */
306 top = partial_end;
307 partial_end = 0;
308 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 wait_on_page_writeback(page);
Lukas Czerner5a720392013-05-27 23:32:35 -0400310 zero_user_segment(page, partial_start, top);
311 cleancache_invalidate_page(mapping, page);
312 if (page_has_private(page))
313 do_invalidatepage(page, partial_start,
314 top - partial_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 unlock_page(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300316 put_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 }
318 }
Lukas Czerner5a720392013-05-27 23:32:35 -0400319 if (partial_end) {
320 struct page *page = find_lock_page(mapping, end);
321 if (page) {
322 wait_on_page_writeback(page);
323 zero_user_segment(page, 0, partial_end);
324 cleancache_invalidate_page(mapping, page);
325 if (page_has_private(page))
326 do_invalidatepage(page, 0,
327 partial_end);
328 unlock_page(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300329 put_page(page);
Lukas Czerner5a720392013-05-27 23:32:35 -0400330 }
331 }
332 /*
333 * If the truncation happened within a single page no pages
334 * will be released, just zeroed, so we can bail out now.
335 */
336 if (start >= end)
337 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700339 index = start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 for ( ; ; ) {
341 cond_resched();
Johannes Weiner0cd61442014-04-03 14:47:46 -0700342 if (!pagevec_lookup_entries(&pvec, mapping, index,
Hugh Dickins792ceae2014-07-23 14:00:15 -0700343 min(end - index, (pgoff_t)PAGEVEC_SIZE), indices)) {
344 /* If all gone from start onwards, we're done */
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700345 if (index == start)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 break;
Hugh Dickins792ceae2014-07-23 14:00:15 -0700347 /* Otherwise restart to make sure all gone */
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700348 index = start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 continue;
350 }
Johannes Weiner0cd61442014-04-03 14:47:46 -0700351 if (index == start && indices[0] >= end) {
Hugh Dickins792ceae2014-07-23 14:00:15 -0700352 /* All gone out of hole to be punched, we're done */
Johannes Weiner0cd61442014-04-03 14:47:46 -0700353 pagevec_remove_exceptionals(&pvec);
Hans Reiserd7339072006-01-06 00:10:36 -0800354 pagevec_release(&pvec);
355 break;
356 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 for (i = 0; i < pagevec_count(&pvec); i++) {
358 struct page *page = pvec.pages[i];
359
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700360 /* We rely upon deletion not changing page->index */
Johannes Weiner0cd61442014-04-03 14:47:46 -0700361 index = indices[i];
Hugh Dickins792ceae2014-07-23 14:00:15 -0700362 if (index >= end) {
363 /* Restart punch to make sure all gone */
364 index = start - 1;
Hans Reiserd7339072006-01-06 00:10:36 -0800365 break;
Hugh Dickins792ceae2014-07-23 14:00:15 -0700366 }
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700367
Johannes Weiner0cd61442014-04-03 14:47:46 -0700368 if (radix_tree_exceptional_entry(page)) {
369 clear_exceptional_entry(mapping, index, page);
370 continue;
371 }
372
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 lock_page(page);
Kirill A. Shutemov5cbc1982016-11-30 15:54:19 -0800374 WARN_ON(page_to_index(page) != index);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 wait_on_page_writeback(page);
Nick Piggin750b4982009-09-16 11:50:12 +0200376 truncate_inode_page(mapping, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 unlock_page(page);
378 }
Johannes Weiner0cd61442014-04-03 14:47:46 -0700379 pagevec_remove_exceptionals(&pvec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 pagevec_release(&pvec);
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700381 index++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 }
Dan Magenheimer31677602011-09-21 11:56:28 -0400383 cleancache_invalidate_inode(mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384}
Hans Reiserd7339072006-01-06 00:10:36 -0800385EXPORT_SYMBOL(truncate_inode_pages_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386
Hans Reiserd7339072006-01-06 00:10:36 -0800387/**
388 * truncate_inode_pages - truncate *all* the pages from an offset
389 * @mapping: mapping to truncate
390 * @lstart: offset from which to truncate
391 *
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800392 * Called under (and serialised by) inode->i_mutex.
Jan Kara08142572011-06-27 16:18:10 -0700393 *
394 * Note: When this function returns, there can be a page in the process of
395 * deletion (inside __delete_from_page_cache()) in the specified range. Thus
396 * mapping->nrpages can be non-zero when this function returns even after
397 * truncation of the whole mapping.
Hans Reiserd7339072006-01-06 00:10:36 -0800398 */
399void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
400{
401 truncate_inode_pages_range(mapping, lstart, (loff_t)-1);
402}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403EXPORT_SYMBOL(truncate_inode_pages);
404
Mike Waychison28697352009-06-16 15:32:59 -0700405/**
Johannes Weiner91b0abe2014-04-03 14:47:49 -0700406 * truncate_inode_pages_final - truncate *all* pages before inode dies
407 * @mapping: mapping to truncate
408 *
409 * Called under (and serialized by) inode->i_mutex.
410 *
411 * Filesystems have to use this in the .evict_inode path to inform the
412 * VM that this is the final truncate and the inode is going away.
413 */
414void truncate_inode_pages_final(struct address_space *mapping)
415{
Ross Zwislerf9fe48b2016-01-22 15:10:40 -0800416 unsigned long nrexceptional;
Johannes Weiner91b0abe2014-04-03 14:47:49 -0700417 unsigned long nrpages;
418
419 /*
420 * Page reclaim can not participate in regular inode lifetime
421 * management (can't call iput()) and thus can race with the
422 * inode teardown. Tell it when the address space is exiting,
423 * so that it does not install eviction information after the
424 * final truncate has begun.
425 */
426 mapping_set_exiting(mapping);
427
428 /*
429 * When reclaim installs eviction entries, it increases
Ross Zwislerf9fe48b2016-01-22 15:10:40 -0800430 * nrexceptional first, then decreases nrpages. Make sure we see
Johannes Weiner91b0abe2014-04-03 14:47:49 -0700431 * this in the right order or we might miss an entry.
432 */
433 nrpages = mapping->nrpages;
434 smp_rmb();
Ross Zwislerf9fe48b2016-01-22 15:10:40 -0800435 nrexceptional = mapping->nrexceptional;
Johannes Weiner91b0abe2014-04-03 14:47:49 -0700436
Ross Zwislerf9fe48b2016-01-22 15:10:40 -0800437 if (nrpages || nrexceptional) {
Johannes Weiner91b0abe2014-04-03 14:47:49 -0700438 /*
439 * As truncation uses a lockless tree lookup, cycle
440 * the tree lock to make sure any ongoing tree
441 * modification that does not see AS_EXITING is
442 * completed before starting the final truncate.
443 */
444 spin_lock_irq(&mapping->tree_lock);
445 spin_unlock_irq(&mapping->tree_lock);
446
447 truncate_inode_pages(mapping, 0);
448 }
449}
450EXPORT_SYMBOL(truncate_inode_pages_final);
451
452/**
Mike Waychison28697352009-06-16 15:32:59 -0700453 * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
454 * @mapping: the address_space which holds the pages to invalidate
455 * @start: the offset 'from' which to invalidate
456 * @end: the offset 'to' which to invalidate (inclusive)
457 *
458 * This function only removes the unlocked pages, if you want to
459 * remove all the pages of one inode, you must call truncate_inode_pages.
460 *
461 * invalidate_mapping_pages() will not block on IO activity. It will not
462 * invalidate pages which are dirty, locked, under writeback or mapped into
463 * pagetables.
464 */
465unsigned long invalidate_mapping_pages(struct address_space *mapping,
Minchan Kim31560182011-03-22 16:32:52 -0700466 pgoff_t start, pgoff_t end)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467{
Johannes Weiner0cd61442014-04-03 14:47:46 -0700468 pgoff_t indices[PAGEVEC_SIZE];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 struct pagevec pvec;
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700470 pgoff_t index = start;
Minchan Kim31560182011-03-22 16:32:52 -0700471 unsigned long ret;
472 unsigned long count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 int i;
474
475 pagevec_init(&pvec, 0);
Johannes Weiner0cd61442014-04-03 14:47:46 -0700476 while (index <= end && pagevec_lookup_entries(&pvec, mapping, index,
477 min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1,
478 indices)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 for (i = 0; i < pagevec_count(&pvec); i++) {
480 struct page *page = pvec.pages[i];
481
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700482 /* We rely upon deletion not changing page->index */
Johannes Weiner0cd61442014-04-03 14:47:46 -0700483 index = indices[i];
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700484 if (index > end)
485 break;
NeilBrowne0f23602006-06-23 02:05:48 -0700486
Johannes Weiner0cd61442014-04-03 14:47:46 -0700487 if (radix_tree_exceptional_entry(page)) {
488 clear_exceptional_entry(mapping, index, page);
489 continue;
490 }
491
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700492 if (!trylock_page(page))
493 continue;
Kirill A. Shutemovfc127da2016-07-26 15:26:07 -0700494
Kirill A. Shutemov5cbc1982016-11-30 15:54:19 -0800495 WARN_ON(page_to_index(page) != index);
Kirill A. Shutemovfc127da2016-07-26 15:26:07 -0700496
497 /* Middle of THP: skip */
498 if (PageTransTail(page)) {
499 unlock_page(page);
500 continue;
501 } else if (PageTransHuge(page)) {
502 index += HPAGE_PMD_NR - 1;
503 i += HPAGE_PMD_NR - 1;
504 /* 'end' is in the middle of THP */
505 if (index == round_down(end, HPAGE_PMD_NR))
506 continue;
507 }
508
Minchan Kim31560182011-03-22 16:32:52 -0700509 ret = invalidate_inode_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 unlock_page(page);
Minchan Kim31560182011-03-22 16:32:52 -0700511 /*
512 * Invalidation is a hint that the page is no longer
513 * of interest and try to speed up its reclaim.
514 */
515 if (!ret)
Minchan Kimcc5993b2015-04-15 16:13:26 -0700516 deactivate_file_page(page);
Minchan Kim31560182011-03-22 16:32:52 -0700517 count += ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 }
Johannes Weiner0cd61442014-04-03 14:47:46 -0700519 pagevec_remove_exceptionals(&pvec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 pagevec_release(&pvec);
Mike Waychison28697352009-06-16 15:32:59 -0700521 cond_resched();
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700522 index++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 }
Minchan Kim31560182011-03-22 16:32:52 -0700524 return count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525}
Anton Altaparmakov54bc4852007-02-10 01:45:38 -0800526EXPORT_SYMBOL(invalidate_mapping_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700528/*
529 * This is like invalidate_complete_page(), except it ignores the page's
530 * refcount. We do this because invalidate_inode_pages2() needs stronger
531 * invalidation guarantees, and cannot afford to leave pages behind because
Anderson Briglia2706a1b2007-07-15 23:38:09 -0700532 * shrink_page_list() has a temp ref on them, or because they're transiently
533 * sitting in the lru_cache_add() pagevecs.
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700534 */
535static int
536invalidate_complete_page2(struct address_space *mapping, struct page *page)
537{
Greg Thelenc4843a72015-05-22 17:13:16 -0400538 unsigned long flags;
539
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700540 if (page->mapping != mapping)
541 return 0;
542
David Howells266cf652009-04-03 16:42:36 +0100543 if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700544 return 0;
545
Greg Thelenc4843a72015-05-22 17:13:16 -0400546 spin_lock_irqsave(&mapping->tree_lock, flags);
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700547 if (PageDirty(page))
548 goto failed;
549
David Howells266cf652009-04-03 16:42:36 +0100550 BUG_ON(page_has_private(page));
Johannes Weiner62cccb82016-03-15 14:57:22 -0700551 __delete_from_page_cache(page, NULL);
Greg Thelenc4843a72015-05-22 17:13:16 -0400552 spin_unlock_irqrestore(&mapping->tree_lock, flags);
Linus Torvalds6072d132010-12-01 13:35:19 -0500553
554 if (mapping->a_ops->freepage)
555 mapping->a_ops->freepage(page);
556
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300557 put_page(page); /* pagecache ref */
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700558 return 1;
559failed:
Greg Thelenc4843a72015-05-22 17:13:16 -0400560 spin_unlock_irqrestore(&mapping->tree_lock, flags);
Andrew Mortonbd4c8ce2006-09-30 23:29:29 -0700561 return 0;
562}
563
Trond Myklebuste3db7692007-01-10 23:15:39 -0800564static int do_launder_page(struct address_space *mapping, struct page *page)
565{
566 if (!PageDirty(page))
567 return 0;
568 if (page->mapping != mapping || mapping->a_ops->launder_page == NULL)
569 return 0;
570 return mapping->a_ops->launder_page(page);
571}
572
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573/**
574 * invalidate_inode_pages2_range - remove range of pages from an address_space
Martin Waitz67be2dd2005-05-01 08:59:26 -0700575 * @mapping: the address_space
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 * @start: the page offset 'from' which to invalidate
577 * @end: the page offset 'to' which to invalidate (inclusive)
578 *
579 * Any pages which are found to be mapped into pagetables are unmapped prior to
580 * invalidation.
581 *
Hisashi Hifumi6ccfa802008-09-02 14:35:40 -0700582 * Returns -EBUSY if any pages could not be invalidated.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 */
584int invalidate_inode_pages2_range(struct address_space *mapping,
585 pgoff_t start, pgoff_t end)
586{
Johannes Weiner0cd61442014-04-03 14:47:46 -0700587 pgoff_t indices[PAGEVEC_SIZE];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 struct pagevec pvec;
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700589 pgoff_t index;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 int i;
591 int ret = 0;
Hisashi Hifumi0dd13342008-04-28 02:12:08 -0700592 int ret2 = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 int did_range_unmap = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594
Dan Magenheimer31677602011-09-21 11:56:28 -0400595 cleancache_invalidate_inode(mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 pagevec_init(&pvec, 0);
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700597 index = start;
Johannes Weiner0cd61442014-04-03 14:47:46 -0700598 while (index <= end && pagevec_lookup_entries(&pvec, mapping, index,
599 min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1,
600 indices)) {
Trond Myklebust7b965e02007-02-28 20:13:55 -0800601 for (i = 0; i < pagevec_count(&pvec); i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 struct page *page = pvec.pages[i];
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700603
604 /* We rely upon deletion not changing page->index */
Johannes Weiner0cd61442014-04-03 14:47:46 -0700605 index = indices[i];
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700606 if (index > end)
607 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608
Johannes Weiner0cd61442014-04-03 14:47:46 -0700609 if (radix_tree_exceptional_entry(page)) {
610 clear_exceptional_entry(mapping, index, page);
611 continue;
612 }
613
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 lock_page(page);
Kirill A. Shutemov5cbc1982016-11-30 15:54:19 -0800615 WARN_ON(page_to_index(page) != index);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 if (page->mapping != mapping) {
617 unlock_page(page);
618 continue;
619 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 wait_on_page_writeback(page);
Nick Piggind00806b2007-07-19 01:46:57 -0700621 if (page_mapped(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 if (!did_range_unmap) {
623 /*
624 * Zap the rest of the file in one hit.
625 */
626 unmap_mapping_range(mapping,
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300627 (loff_t)index << PAGE_SHIFT,
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700628 (loff_t)(1 + end - index)
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300629 << PAGE_SHIFT,
630 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 did_range_unmap = 1;
632 } else {
633 /*
634 * Just zap this page
635 */
636 unmap_mapping_range(mapping,
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300637 (loff_t)index << PAGE_SHIFT,
638 PAGE_SIZE, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 }
640 }
Nick Piggind00806b2007-07-19 01:46:57 -0700641 BUG_ON(page_mapped(page));
Hisashi Hifumi0dd13342008-04-28 02:12:08 -0700642 ret2 = do_launder_page(mapping, page);
643 if (ret2 == 0) {
644 if (!invalidate_complete_page2(mapping, page))
Hisashi Hifumi6ccfa802008-09-02 14:35:40 -0700645 ret2 = -EBUSY;
Hisashi Hifumi0dd13342008-04-28 02:12:08 -0700646 }
647 if (ret2 < 0)
648 ret = ret2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 unlock_page(page);
650 }
Johannes Weiner0cd61442014-04-03 14:47:46 -0700651 pagevec_remove_exceptionals(&pvec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 pagevec_release(&pvec);
653 cond_resched();
Hugh Dickinsb85e0ef2011-07-25 17:12:25 -0700654 index++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 }
Dan Magenheimer31677602011-09-21 11:56:28 -0400656 cleancache_invalidate_inode(mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 return ret;
658}
659EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
660
661/**
662 * invalidate_inode_pages2 - remove all pages from an address_space
Martin Waitz67be2dd2005-05-01 08:59:26 -0700663 * @mapping: the address_space
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 *
665 * Any pages which are found to be mapped into pagetables are unmapped prior to
666 * invalidation.
667 *
Peng Taoe9de25d2009-10-19 14:48:13 +0800668 * Returns -EBUSY if any pages could not be invalidated.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 */
670int invalidate_inode_pages2(struct address_space *mapping)
671{
672 return invalidate_inode_pages2_range(mapping, 0, -1);
673}
674EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +1000675
676/**
677 * truncate_pagecache - unmap and remove pagecache that has been truncated
678 * @inode: inode
Hugh Dickins8a549be2011-07-25 17:12:24 -0700679 * @newsize: new file size
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +1000680 *
681 * inode's new i_size must already be written before truncate_pagecache
682 * is called.
683 *
684 * This function should typically be called before the filesystem
685 * releases resources associated with the freed range (eg. deallocates
686 * blocks). This way, pagecache will always stay logically coherent
687 * with on-disk format, and the filesystem would not have to deal with
688 * situations such as writepage being called for a page that has already
689 * had its underlying blocks deallocated.
690 */
Kirill A. Shutemov7caef262013-09-12 15:13:56 -0700691void truncate_pagecache(struct inode *inode, loff_t newsize)
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +1000692{
OGAWA Hirofumicedabed2010-01-13 21:14:09 +0900693 struct address_space *mapping = inode->i_mapping;
Hugh Dickins8a549be2011-07-25 17:12:24 -0700694 loff_t holebegin = round_up(newsize, PAGE_SIZE);
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +1000695
OGAWA Hirofumicedabed2010-01-13 21:14:09 +0900696 /*
697 * unmap_mapping_range is called twice, first simply for
698 * efficiency so that truncate_inode_pages does fewer
699 * single-page unmaps. However after this first call, and
700 * before truncate_inode_pages finishes, it is possible for
701 * private pages to be COWed, which remain after
702 * truncate_inode_pages finishes, hence the second
703 * unmap_mapping_range call must be made for correctness.
704 */
Hugh Dickins8a549be2011-07-25 17:12:24 -0700705 unmap_mapping_range(mapping, holebegin, 0, 1);
706 truncate_inode_pages(mapping, newsize);
707 unmap_mapping_range(mapping, holebegin, 0, 1);
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +1000708}
709EXPORT_SYMBOL(truncate_pagecache);
710
711/**
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200712 * truncate_setsize - update inode and pagecache for a new file size
713 * @inode: inode
714 * @newsize: new file size
715 *
Jan Kara382e27d2011-01-20 14:44:26 -0800716 * truncate_setsize updates i_size and performs pagecache truncation (if
717 * necessary) to @newsize. It will be typically be called from the filesystem's
718 * setattr function when ATTR_SIZE is passed in.
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200719 *
Jan Kara77783d02014-11-07 08:29:25 +1100720 * Must be called with a lock serializing truncates and writes (generally
721 * i_mutex but e.g. xfs uses a different lock) and before all filesystem
722 * specific block truncation has been performed.
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200723 */
724void truncate_setsize(struct inode *inode, loff_t newsize)
725{
Jan Kara90a80202014-10-01 21:49:18 -0400726 loff_t oldsize = inode->i_size;
727
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200728 i_size_write(inode, newsize);
Jan Kara90a80202014-10-01 21:49:18 -0400729 if (newsize > oldsize)
730 pagecache_isize_extended(inode, oldsize, newsize);
Kirill A. Shutemov7caef262013-09-12 15:13:56 -0700731 truncate_pagecache(inode, newsize);
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200732}
733EXPORT_SYMBOL(truncate_setsize);
734
735/**
Jan Kara90a80202014-10-01 21:49:18 -0400736 * pagecache_isize_extended - update pagecache after extension of i_size
737 * @inode: inode for which i_size was extended
738 * @from: original inode size
739 * @to: new inode size
740 *
741 * Handle extension of inode size either caused by extending truncate or by
742 * write starting after current i_size. We mark the page straddling current
743 * i_size RO so that page_mkwrite() is called on the nearest write access to
744 * the page. This way filesystem can be sure that page_mkwrite() is called on
745 * the page before user writes to the page via mmap after the i_size has been
746 * changed.
747 *
748 * The function must be called after i_size is updated so that page fault
749 * coming after we unlock the page will already see the new i_size.
750 * The function must be called while we still hold i_mutex - this not only
751 * makes sure i_size is stable but also that userspace cannot observe new
752 * i_size value before we are prepared to store mmap writes at new inode size.
753 */
754void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to)
755{
Fabian Frederick61604a22017-02-27 14:28:32 -0800756 int bsize = i_blocksize(inode);
Jan Kara90a80202014-10-01 21:49:18 -0400757 loff_t rounded_from;
758 struct page *page;
759 pgoff_t index;
760
Jan Kara90a80202014-10-01 21:49:18 -0400761 WARN_ON(to > inode->i_size);
762
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300763 if (from >= to || bsize == PAGE_SIZE)
Jan Kara90a80202014-10-01 21:49:18 -0400764 return;
765 /* Page straddling @from will not have any hole block created? */
766 rounded_from = round_up(from, bsize);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300767 if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1)))
Jan Kara90a80202014-10-01 21:49:18 -0400768 return;
769
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300770 index = from >> PAGE_SHIFT;
Jan Kara90a80202014-10-01 21:49:18 -0400771 page = find_lock_page(inode->i_mapping, index);
772 /* Page not cached? Nothing to do */
773 if (!page)
774 return;
775 /*
776 * See clear_page_dirty_for_io() for details why set_page_dirty()
777 * is needed.
778 */
779 if (page_mkclean(page))
780 set_page_dirty(page);
781 unlock_page(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300782 put_page(page);
Jan Kara90a80202014-10-01 21:49:18 -0400783}
784EXPORT_SYMBOL(pagecache_isize_extended);
785
786/**
Hugh Dickins623e3db2012-03-28 14:42:40 -0700787 * truncate_pagecache_range - unmap and remove pagecache that is hole-punched
788 * @inode: inode
789 * @lstart: offset of beginning of hole
790 * @lend: offset of last byte of hole
791 *
792 * This function should typically be called before the filesystem
793 * releases resources associated with the freed range (eg. deallocates
794 * blocks). This way, pagecache will always stay logically coherent
795 * with on-disk format, and the filesystem would not have to deal with
796 * situations such as writepage being called for a page that has already
797 * had its underlying blocks deallocated.
798 */
799void truncate_pagecache_range(struct inode *inode, loff_t lstart, loff_t lend)
800{
801 struct address_space *mapping = inode->i_mapping;
802 loff_t unmap_start = round_up(lstart, PAGE_SIZE);
803 loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1;
804 /*
805 * This rounding is currently just for example: unmap_mapping_range
806 * expands its hole outwards, whereas we want it to contract the hole
807 * inwards. However, existing callers of truncate_pagecache_range are
Lukas Czerner5a720392013-05-27 23:32:35 -0400808 * doing their own page rounding first. Note that unmap_mapping_range
809 * allows holelen 0 for all, and we allow lend -1 for end of file.
Hugh Dickins623e3db2012-03-28 14:42:40 -0700810 */
811
812 /*
813 * Unlike in truncate_pagecache, unmap_mapping_range is called only
814 * once (before truncating pagecache), and without "even_cows" flag:
815 * hole-punching should not remove private COWed pages from the hole.
816 */
817 if ((u64)unmap_end > (u64)unmap_start)
818 unmap_mapping_range(mapping, unmap_start,
819 1 + unmap_end - unmap_start, 0);
820 truncate_inode_pages_range(mapping, lstart, lend);
821}
822EXPORT_SYMBOL(truncate_pagecache_range);