blob: a2692bbc7b50a510b1723b95fd7d060b74bbedb9 [file] [log] [blame]
Ryusuke Konishi0bd49f92009-04-06 19:01:27 -07001/*
2 * page.c - buffer/page management specific to NILFS
3 *
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 *
20 * Written by Ryusuke Konishi <ryusuke@osrg.net>,
21 * Seiji Kihara <kihara@osrg.net>.
22 */
23
24#include <linux/pagemap.h>
25#include <linux/writeback.h>
26#include <linux/swap.h>
27#include <linux/bitops.h>
28#include <linux/page-flags.h>
29#include <linux/list.h>
30#include <linux/highmem.h>
31#include <linux/pagevec.h>
32#include "nilfs.h"
33#include "page.h"
34#include "mdt.h"
35
36
37#define NILFS_BUFFER_INHERENT_BITS \
38 ((1UL << BH_Uptodate) | (1UL << BH_Mapped) | (1UL << BH_NILFS_Node) | \
39 (1UL << BH_NILFS_Volatile) | (1UL << BH_NILFS_Allocated))
40
41static struct buffer_head *
42__nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
43 int blkbits, unsigned long b_state)
44
45{
46 unsigned long first_block;
47 struct buffer_head *bh;
48
49 if (!page_has_buffers(page))
50 create_empty_buffers(page, 1 << blkbits, b_state);
51
52 first_block = (unsigned long)index << (PAGE_CACHE_SHIFT - blkbits);
53 bh = nilfs_page_get_nth_block(page, block - first_block);
54
55 touch_buffer(bh);
56 wait_on_buffer(bh);
57 return bh;
58}
59
60/*
61 * Since the page cache of B-tree node pages or data page cache of pseudo
62 * inodes does not have a valid mapping->host pointer, calling
63 * mark_buffer_dirty() for their buffers causes a NULL pointer dereference;
64 * it calls __mark_inode_dirty(NULL) through __set_page_dirty().
65 * To avoid this problem, the old style mark_buffer_dirty() is used instead.
66 */
67void nilfs_mark_buffer_dirty(struct buffer_head *bh)
68{
69 if (!buffer_dirty(bh) && !test_set_buffer_dirty(bh))
70 __set_page_dirty_nobuffers(bh->b_page);
71}
72
73struct buffer_head *nilfs_grab_buffer(struct inode *inode,
74 struct address_space *mapping,
75 unsigned long blkoff,
76 unsigned long b_state)
77{
78 int blkbits = inode->i_blkbits;
79 pgoff_t index = blkoff >> (PAGE_CACHE_SHIFT - blkbits);
80 struct page *page, *opage;
81 struct buffer_head *bh, *obh;
82
83 page = grab_cache_page(mapping, index);
84 if (unlikely(!page))
85 return NULL;
86
87 bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
88 if (unlikely(!bh)) {
89 unlock_page(page);
90 page_cache_release(page);
91 return NULL;
92 }
93 if (!buffer_uptodate(bh) && mapping->assoc_mapping != NULL) {
94 /*
95 * Shadow page cache uses assoc_mapping to point its original
96 * page cache. The following code tries the original cache
97 * if the given cache is a shadow and it didn't hit.
98 */
99 opage = find_lock_page(mapping->assoc_mapping, index);
100 if (!opage)
101 return bh;
102
103 obh = __nilfs_get_page_block(opage, blkoff, index, blkbits,
104 b_state);
105 if (buffer_uptodate(obh)) {
106 nilfs_copy_buffer(bh, obh);
107 if (buffer_dirty(obh)) {
108 nilfs_mark_buffer_dirty(bh);
109 if (!buffer_nilfs_node(bh) && NILFS_MDT(inode))
110 nilfs_mdt_mark_dirty(inode);
111 }
112 }
113 brelse(obh);
114 unlock_page(opage);
115 page_cache_release(opage);
116 }
117 return bh;
118}
119
120/**
121 * nilfs_forget_buffer - discard dirty state
122 * @inode: owner inode of the buffer
123 * @bh: buffer head of the buffer to be discarded
124 */
125void nilfs_forget_buffer(struct buffer_head *bh)
126{
127 struct page *page = bh->b_page;
128
129 lock_buffer(bh);
130 clear_buffer_nilfs_volatile(bh);
Ryusuke Konishi84338232009-05-05 21:52:06 +0900131 clear_buffer_dirty(bh);
132 if (nilfs_page_buffers_clean(page))
Ryusuke Konishi0bd49f92009-04-06 19:01:27 -0700133 __nilfs_clear_page_dirty(page);
134
135 clear_buffer_uptodate(bh);
136 clear_buffer_mapped(bh);
137 bh->b_blocknr = -1;
138 ClearPageUptodate(page);
139 ClearPageMappedToDisk(page);
140 unlock_buffer(bh);
141 brelse(bh);
142}
143
144/**
145 * nilfs_copy_buffer -- copy buffer data and flags
146 * @dbh: destination buffer
147 * @sbh: source buffer
148 */
149void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
150{
151 void *kaddr0, *kaddr1;
152 unsigned long bits;
153 struct page *spage = sbh->b_page, *dpage = dbh->b_page;
154 struct buffer_head *bh;
155
156 kaddr0 = kmap_atomic(spage, KM_USER0);
157 kaddr1 = kmap_atomic(dpage, KM_USER1);
158 memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
159 kunmap_atomic(kaddr1, KM_USER1);
160 kunmap_atomic(kaddr0, KM_USER0);
161
162 dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
163 dbh->b_blocknr = sbh->b_blocknr;
164 dbh->b_bdev = sbh->b_bdev;
165
166 bh = dbh;
167 bits = sbh->b_state & ((1UL << BH_Uptodate) | (1UL << BH_Mapped));
168 while ((bh = bh->b_this_page) != dbh) {
169 lock_buffer(bh);
170 bits &= bh->b_state;
171 unlock_buffer(bh);
172 }
173 if (bits & (1UL << BH_Uptodate))
174 SetPageUptodate(dpage);
175 else
176 ClearPageUptodate(dpage);
177 if (bits & (1UL << BH_Mapped))
178 SetPageMappedToDisk(dpage);
179 else
180 ClearPageMappedToDisk(dpage);
181}
182
183/**
184 * nilfs_page_buffers_clean - check if a page has dirty buffers or not.
185 * @page: page to be checked
186 *
187 * nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
188 * Otherwise, it returns non-zero value.
189 */
190int nilfs_page_buffers_clean(struct page *page)
191{
192 struct buffer_head *bh, *head;
193
194 bh = head = page_buffers(page);
195 do {
196 if (buffer_dirty(bh))
197 return 0;
198 bh = bh->b_this_page;
199 } while (bh != head);
200 return 1;
201}
202
203void nilfs_page_bug(struct page *page)
204{
205 struct address_space *m;
206 unsigned long ino = 0;
207
208 if (unlikely(!page)) {
209 printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
210 return;
211 }
212
213 m = page->mapping;
214 if (m) {
215 struct inode *inode = NILFS_AS_I(m);
216 if (inode != NULL)
217 ino = inode->i_ino;
218 }
219 printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
220 "mapping=%p ino=%lu\n",
221 page, atomic_read(&page->_count),
222 (unsigned long long)page->index, page->flags, m, ino);
223
224 if (page_has_buffers(page)) {
225 struct buffer_head *bh, *head;
226 int i = 0;
227
228 bh = head = page_buffers(page);
229 do {
230 printk(KERN_CRIT
231 " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
232 i++, bh, atomic_read(&bh->b_count),
233 (unsigned long long)bh->b_blocknr, bh->b_state);
234 bh = bh->b_this_page;
235 } while (bh != head);
236 }
237}
238
239/**
240 * nilfs_alloc_private_page - allocate a private page with buffer heads
241 *
242 * Return Value: On success, a pointer to the allocated page is returned.
243 * On error, NULL is returned.
244 */
245struct page *nilfs_alloc_private_page(struct block_device *bdev, int size,
246 unsigned long state)
247{
248 struct buffer_head *bh, *head, *tail;
249 struct page *page;
250
251 page = alloc_page(GFP_NOFS); /* page_count of the returned page is 1 */
252 if (unlikely(!page))
253 return NULL;
254
255 lock_page(page);
256 head = alloc_page_buffers(page, size, 0);
257 if (unlikely(!head)) {
258 unlock_page(page);
259 __free_page(page);
260 return NULL;
261 }
262
263 bh = head;
264 do {
265 bh->b_state = (1UL << BH_NILFS_Allocated) | state;
266 tail = bh;
267 bh->b_bdev = bdev;
268 bh = bh->b_this_page;
269 } while (bh);
270
271 tail->b_this_page = head;
272 attach_page_buffers(page, head);
273
274 return page;
275}
276
277void nilfs_free_private_page(struct page *page)
278{
279 BUG_ON(!PageLocked(page));
280 BUG_ON(page->mapping);
281
282 if (page_has_buffers(page) && !try_to_free_buffers(page))
283 NILFS_PAGE_BUG(page, "failed to free page");
284
285 unlock_page(page);
286 __free_page(page);
287}
288
289/**
290 * nilfs_copy_page -- copy the page with buffers
291 * @dst: destination page
292 * @src: source page
293 * @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
294 *
295 * This fuction is for both data pages and btnode pages. The dirty flag
296 * should be treated by caller. The page must not be under i/o.
297 * Both src and dst page must be locked
298 */
299static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
300{
301 struct buffer_head *dbh, *dbufs, *sbh, *sbufs;
302 unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
303
304 BUG_ON(PageWriteback(dst));
305
306 sbh = sbufs = page_buffers(src);
307 if (!page_has_buffers(dst))
308 create_empty_buffers(dst, sbh->b_size, 0);
309
310 if (copy_dirty)
311 mask |= (1UL << BH_Dirty);
312
313 dbh = dbufs = page_buffers(dst);
314 do {
315 lock_buffer(sbh);
316 lock_buffer(dbh);
317 dbh->b_state = sbh->b_state & mask;
318 dbh->b_blocknr = sbh->b_blocknr;
319 dbh->b_bdev = sbh->b_bdev;
320 sbh = sbh->b_this_page;
321 dbh = dbh->b_this_page;
322 } while (dbh != dbufs);
323
324 copy_highpage(dst, src);
325
326 if (PageUptodate(src) && !PageUptodate(dst))
327 SetPageUptodate(dst);
328 else if (!PageUptodate(src) && PageUptodate(dst))
329 ClearPageUptodate(dst);
330 if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
331 SetPageMappedToDisk(dst);
332 else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
333 ClearPageMappedToDisk(dst);
334
335 do {
336 unlock_buffer(sbh);
337 unlock_buffer(dbh);
338 sbh = sbh->b_this_page;
339 dbh = dbh->b_this_page;
340 } while (dbh != dbufs);
341}
342
343int nilfs_copy_dirty_pages(struct address_space *dmap,
344 struct address_space *smap)
345{
346 struct pagevec pvec;
347 unsigned int i;
348 pgoff_t index = 0;
349 int err = 0;
350
351 pagevec_init(&pvec, 0);
352repeat:
353 if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY,
354 PAGEVEC_SIZE))
355 return 0;
356
357 for (i = 0; i < pagevec_count(&pvec); i++) {
358 struct page *page = pvec.pages[i], *dpage;
359
360 lock_page(page);
361 if (unlikely(!PageDirty(page)))
362 NILFS_PAGE_BUG(page, "inconsistent dirty state");
363
364 dpage = grab_cache_page(dmap, page->index);
365 if (unlikely(!dpage)) {
366 /* No empty page is added to the page cache */
367 err = -ENOMEM;
368 unlock_page(page);
369 break;
370 }
371 if (unlikely(!page_has_buffers(page)))
372 NILFS_PAGE_BUG(page,
373 "found empty page in dat page cache");
374
375 nilfs_copy_page(dpage, page, 1);
376 __set_page_dirty_nobuffers(dpage);
377
378 unlock_page(dpage);
379 page_cache_release(dpage);
380 unlock_page(page);
381 }
382 pagevec_release(&pvec);
383 cond_resched();
384
385 if (likely(!err))
386 goto repeat;
387 return err;
388}
389
390/**
391 * nilfs_copy_back_pages -- copy back pages to orignal cache from shadow cache
392 * @dmap: destination page cache
393 * @smap: source page cache
394 *
395 * No pages must no be added to the cache during this process.
396 * This must be ensured by the caller.
397 */
398void nilfs_copy_back_pages(struct address_space *dmap,
399 struct address_space *smap)
400{
401 struct pagevec pvec;
402 unsigned int i, n;
403 pgoff_t index = 0;
404 int err;
405
406 pagevec_init(&pvec, 0);
407repeat:
408 n = pagevec_lookup(&pvec, smap, index, PAGEVEC_SIZE);
409 if (!n)
410 return;
411 index = pvec.pages[n - 1]->index + 1;
412
413 for (i = 0; i < pagevec_count(&pvec); i++) {
414 struct page *page = pvec.pages[i], *dpage;
415 pgoff_t offset = page->index;
416
417 lock_page(page);
418 dpage = find_lock_page(dmap, offset);
419 if (dpage) {
420 /* override existing page on the destination cache */
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700421 WARN_ON(PageDirty(dpage));
Ryusuke Konishi0bd49f92009-04-06 19:01:27 -0700422 nilfs_copy_page(dpage, page, 0);
423 unlock_page(dpage);
424 page_cache_release(dpage);
425 } else {
426 struct page *page2;
427
428 /* move the page to the destination cache */
429 spin_lock_irq(&smap->tree_lock);
430 page2 = radix_tree_delete(&smap->page_tree, offset);
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700431 WARN_ON(page2 != page);
432
Ryusuke Konishi0bd49f92009-04-06 19:01:27 -0700433 smap->nrpages--;
434 spin_unlock_irq(&smap->tree_lock);
435
436 spin_lock_irq(&dmap->tree_lock);
437 err = radix_tree_insert(&dmap->page_tree, offset, page);
438 if (unlikely(err < 0)) {
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700439 WARN_ON(err == -EEXIST);
Ryusuke Konishi0bd49f92009-04-06 19:01:27 -0700440 page->mapping = NULL;
441 page_cache_release(page); /* for cache */
442 } else {
443 page->mapping = dmap;
444 dmap->nrpages++;
445 if (PageDirty(page))
446 radix_tree_tag_set(&dmap->page_tree,
447 offset,
448 PAGECACHE_TAG_DIRTY);
449 }
450 spin_unlock_irq(&dmap->tree_lock);
451 }
452 unlock_page(page);
453 }
454 pagevec_release(&pvec);
455 cond_resched();
456
457 goto repeat;
458}
459
460void nilfs_clear_dirty_pages(struct address_space *mapping)
461{
462 struct pagevec pvec;
463 unsigned int i;
464 pgoff_t index = 0;
465
466 pagevec_init(&pvec, 0);
467
468 while (pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
469 PAGEVEC_SIZE)) {
470 for (i = 0; i < pagevec_count(&pvec); i++) {
471 struct page *page = pvec.pages[i];
472 struct buffer_head *bh, *head;
473
474 lock_page(page);
475 ClearPageUptodate(page);
476 ClearPageMappedToDisk(page);
477 bh = head = page_buffers(page);
478 do {
479 lock_buffer(bh);
480 clear_buffer_dirty(bh);
481 clear_buffer_nilfs_volatile(bh);
482 clear_buffer_uptodate(bh);
483 clear_buffer_mapped(bh);
484 unlock_buffer(bh);
485 bh = bh->b_this_page;
486 } while (bh != head);
487
488 __nilfs_clear_page_dirty(page);
489 unlock_page(page);
490 }
491 pagevec_release(&pvec);
492 cond_resched();
493 }
494}
495
496unsigned nilfs_page_count_clean_buffers(struct page *page,
497 unsigned from, unsigned to)
498{
499 unsigned block_start, block_end;
500 struct buffer_head *bh, *head;
501 unsigned nc = 0;
502
503 for (bh = head = page_buffers(page), block_start = 0;
504 bh != head || !block_start;
505 block_start = block_end, bh = bh->b_this_page) {
506 block_end = block_start + bh->b_size;
507 if (block_end > from && block_start < to && !buffer_dirty(bh))
508 nc++;
509 }
510 return nc;
511}
512
513/*
514 * NILFS2 needs clear_page_dirty() in the following two cases:
515 *
516 * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
517 * page dirty flags when it copies back pages from the shadow cache
518 * (gcdat->{i_mapping,i_btnode_cache}) to its original cache
519 * (dat->{i_mapping,i_btnode_cache}).
520 *
521 * 2) Some B-tree operations like insertion or deletion may dispose buffers
522 * in dirty state, and this needs to cancel the dirty state of their pages.
523 */
524int __nilfs_clear_page_dirty(struct page *page)
525{
526 struct address_space *mapping = page->mapping;
527
528 if (mapping) {
529 spin_lock_irq(&mapping->tree_lock);
530 if (test_bit(PG_dirty, &page->flags)) {
531 radix_tree_tag_clear(&mapping->page_tree,
532 page_index(page),
533 PAGECACHE_TAG_DIRTY);
534 spin_unlock_irq(&mapping->tree_lock);
535 return clear_page_dirty_for_io(page);
536 }
537 spin_unlock_irq(&mapping->tree_lock);
538 return 0;
539 }
540 return TestClearPageDirty(page);
541}