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1/*
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 * Written by Ryusuke Konishi and Seiji Kihara.
17 */
18
19#include <linux/pagemap.h>
20#include <linux/writeback.h>
21#include <linux/swap.h>
22#include <linux/bitops.h>
23#include <linux/page-flags.h>
24#include <linux/list.h>
25#include <linux/highmem.h>
26#include <linux/pagevec.h>
27#include <linux/gfp.h>
28#include "nilfs.h"
29#include "page.h"
30#include "mdt.h"
31
32
33#define NILFS_BUFFER_INHERENT_BITS \
34 (BIT(BH_Uptodate) | BIT(BH_Mapped) | BIT(BH_NILFS_Node) | \
35 BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Checked))
36
37static struct buffer_head *
38__nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
39 int blkbits, unsigned long b_state)
40
41{
42 unsigned long first_block;
43 struct buffer_head *bh;
44
45 if (!page_has_buffers(page))
46 create_empty_buffers(page, 1 << blkbits, b_state);
47
48 first_block = (unsigned long)index << (PAGE_SHIFT - blkbits);
49 bh = nilfs_page_get_nth_block(page, block - first_block);
50
51 touch_buffer(bh);
52 wait_on_buffer(bh);
53 return bh;
54}
55
56struct buffer_head *nilfs_grab_buffer(struct inode *inode,
57 struct address_space *mapping,
58 unsigned long blkoff,
59 unsigned long b_state)
60{
61 int blkbits = inode->i_blkbits;
62 pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits);
63 struct page *page;
64 struct buffer_head *bh;
65
66 page = grab_cache_page(mapping, index);
67 if (unlikely(!page))
68 return NULL;
69
70 bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
71 if (unlikely(!bh)) {
72 unlock_page(page);
73 put_page(page);
74 return NULL;
75 }
76 return bh;
77}
78
79/**
80 * nilfs_forget_buffer - discard dirty state
81 * @inode: owner inode of the buffer
82 * @bh: buffer head of the buffer to be discarded
83 */
84void nilfs_forget_buffer(struct buffer_head *bh)
85{
86 struct page *page = bh->b_page;
87 const unsigned long clear_bits =
88 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
89 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
90 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
91
92 lock_buffer(bh);
93 set_mask_bits(&bh->b_state, clear_bits, 0);
94 if (nilfs_page_buffers_clean(page))
95 __nilfs_clear_page_dirty(page);
96
97 bh->b_blocknr = -1;
98 ClearPageUptodate(page);
99 ClearPageMappedToDisk(page);
100 unlock_buffer(bh);
101 brelse(bh);
102}
103
104/**
105 * nilfs_copy_buffer -- copy buffer data and flags
106 * @dbh: destination buffer
107 * @sbh: source buffer
108 */
109void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
110{
111 void *kaddr0, *kaddr1;
112 unsigned long bits;
113 struct page *spage = sbh->b_page, *dpage = dbh->b_page;
114 struct buffer_head *bh;
115
116 kaddr0 = kmap_atomic(spage);
117 kaddr1 = kmap_atomic(dpage);
118 memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
119 kunmap_atomic(kaddr1);
120 kunmap_atomic(kaddr0);
121
122 dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
123 dbh->b_blocknr = sbh->b_blocknr;
124 dbh->b_bdev = sbh->b_bdev;
125
126 bh = dbh;
127 bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped));
128 while ((bh = bh->b_this_page) != dbh) {
129 lock_buffer(bh);
130 bits &= bh->b_state;
131 unlock_buffer(bh);
132 }
133 if (bits & BIT(BH_Uptodate))
134 SetPageUptodate(dpage);
135 else
136 ClearPageUptodate(dpage);
137 if (bits & BIT(BH_Mapped))
138 SetPageMappedToDisk(dpage);
139 else
140 ClearPageMappedToDisk(dpage);
141}
142
143/**
144 * nilfs_page_buffers_clean - check if a page has dirty buffers or not.
145 * @page: page to be checked
146 *
147 * nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
148 * Otherwise, it returns non-zero value.
149 */
150int nilfs_page_buffers_clean(struct page *page)
151{
152 struct buffer_head *bh, *head;
153
154 bh = head = page_buffers(page);
155 do {
156 if (buffer_dirty(bh))
157 return 0;
158 bh = bh->b_this_page;
159 } while (bh != head);
160 return 1;
161}
162
163void nilfs_page_bug(struct page *page)
164{
165 struct address_space *m;
166 unsigned long ino;
167
168 if (unlikely(!page)) {
169 printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
170 return;
171 }
172
173 m = page->mapping;
174 ino = m ? m->host->i_ino : 0;
175
176 printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
177 "mapping=%p ino=%lu\n",
178 page, page_ref_count(page),
179 (unsigned long long)page->index, page->flags, m, ino);
180
181 if (page_has_buffers(page)) {
182 struct buffer_head *bh, *head;
183 int i = 0;
184
185 bh = head = page_buffers(page);
186 do {
187 printk(KERN_CRIT
188 " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
189 i++, bh, atomic_read(&bh->b_count),
190 (unsigned long long)bh->b_blocknr, bh->b_state);
191 bh = bh->b_this_page;
192 } while (bh != head);
193 }
194}
195
196/**
197 * nilfs_copy_page -- copy the page with buffers
198 * @dst: destination page
199 * @src: source page
200 * @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
201 *
202 * This function is for both data pages and btnode pages. The dirty flag
203 * should be treated by caller. The page must not be under i/o.
204 * Both src and dst page must be locked
205 */
206static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
207{
208 struct buffer_head *dbh, *dbufs, *sbh, *sbufs;
209 unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
210
211 BUG_ON(PageWriteback(dst));
212
213 sbh = sbufs = page_buffers(src);
214 if (!page_has_buffers(dst))
215 create_empty_buffers(dst, sbh->b_size, 0);
216
217 if (copy_dirty)
218 mask |= BIT(BH_Dirty);
219
220 dbh = dbufs = page_buffers(dst);
221 do {
222 lock_buffer(sbh);
223 lock_buffer(dbh);
224 dbh->b_state = sbh->b_state & mask;
225 dbh->b_blocknr = sbh->b_blocknr;
226 dbh->b_bdev = sbh->b_bdev;
227 sbh = sbh->b_this_page;
228 dbh = dbh->b_this_page;
229 } while (dbh != dbufs);
230
231 copy_highpage(dst, src);
232
233 if (PageUptodate(src) && !PageUptodate(dst))
234 SetPageUptodate(dst);
235 else if (!PageUptodate(src) && PageUptodate(dst))
236 ClearPageUptodate(dst);
237 if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
238 SetPageMappedToDisk(dst);
239 else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
240 ClearPageMappedToDisk(dst);
241
242 do {
243 unlock_buffer(sbh);
244 unlock_buffer(dbh);
245 sbh = sbh->b_this_page;
246 dbh = dbh->b_this_page;
247 } while (dbh != dbufs);
248}
249
250int nilfs_copy_dirty_pages(struct address_space *dmap,
251 struct address_space *smap)
252{
253 struct pagevec pvec;
254 unsigned int i;
255 pgoff_t index = 0;
256 int err = 0;
257
258 pagevec_init(&pvec);
259repeat:
260 if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY))
261 return 0;
262
263 for (i = 0; i < pagevec_count(&pvec); i++) {
264 struct page *page = pvec.pages[i], *dpage;
265
266 lock_page(page);
267 if (unlikely(!PageDirty(page)))
268 NILFS_PAGE_BUG(page, "inconsistent dirty state");
269
270 dpage = grab_cache_page(dmap, page->index);
271 if (unlikely(!dpage)) {
272 /* No empty page is added to the page cache */
273 err = -ENOMEM;
274 unlock_page(page);
275 break;
276 }
277 if (unlikely(!page_has_buffers(page)))
278 NILFS_PAGE_BUG(page,
279 "found empty page in dat page cache");
280
281 nilfs_copy_page(dpage, page, 1);
282 __set_page_dirty_nobuffers(dpage);
283
284 unlock_page(dpage);
285 put_page(dpage);
286 unlock_page(page);
287 }
288 pagevec_release(&pvec);
289 cond_resched();
290
291 if (likely(!err))
292 goto repeat;
293 return err;
294}
295
296/**
297 * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
298 * @dmap: destination page cache
299 * @smap: source page cache
300 *
301 * No pages must no be added to the cache during this process.
302 * This must be ensured by the caller.
303 */
304void nilfs_copy_back_pages(struct address_space *dmap,
305 struct address_space *smap)
306{
307 struct pagevec pvec;
308 unsigned int i, n;
309 pgoff_t index = 0;
310 int err;
311
312 pagevec_init(&pvec);
313repeat:
314 n = pagevec_lookup(&pvec, smap, &index);
315 if (!n)
316 return;
317
318 for (i = 0; i < pagevec_count(&pvec); i++) {
319 struct page *page = pvec.pages[i], *dpage;
320 pgoff_t offset = page->index;
321
322 lock_page(page);
323 dpage = find_lock_page(dmap, offset);
324 if (dpage) {
325 /* override existing page on the destination cache */
326 WARN_ON(PageDirty(dpage));
327 nilfs_copy_page(dpage, page, 0);
328 unlock_page(dpage);
329 put_page(dpage);
330 } else {
331 struct page *page2;
332
333 /* move the page to the destination cache */
334 xa_lock_irq(&smap->i_pages);
335 page2 = radix_tree_delete(&smap->i_pages, offset);
336 WARN_ON(page2 != page);
337
338 smap->nrpages--;
339 xa_unlock_irq(&smap->i_pages);
340
341 xa_lock_irq(&dmap->i_pages);
342 err = radix_tree_insert(&dmap->i_pages, offset, page);
343 if (unlikely(err < 0)) {
344 WARN_ON(err == -EEXIST);
345 page->mapping = NULL;
346 put_page(page); /* for cache */
347 } else {
348 page->mapping = dmap;
349 dmap->nrpages++;
350 if (PageDirty(page))
351 radix_tree_tag_set(&dmap->i_pages,
352 offset,
353 PAGECACHE_TAG_DIRTY);
354 }
355 xa_unlock_irq(&dmap->i_pages);
356 }
357 unlock_page(page);
358 }
359 pagevec_release(&pvec);
360 cond_resched();
361
362 goto repeat;
363}
364
365/**
366 * nilfs_clear_dirty_pages - discard dirty pages in address space
367 * @mapping: address space with dirty pages for discarding
368 * @silent: suppress [true] or print [false] warning messages
369 */
370void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
371{
372 struct pagevec pvec;
373 unsigned int i;
374 pgoff_t index = 0;
375
376 pagevec_init(&pvec);
377
378 while (pagevec_lookup_tag(&pvec, mapping, &index,
379 PAGECACHE_TAG_DIRTY)) {
380 for (i = 0; i < pagevec_count(&pvec); i++) {
381 struct page *page = pvec.pages[i];
382
383 lock_page(page);
384 nilfs_clear_dirty_page(page, silent);
385 unlock_page(page);
386 }
387 pagevec_release(&pvec);
388 cond_resched();
389 }
390}
391
392/**
393 * nilfs_clear_dirty_page - discard dirty page
394 * @page: dirty page that will be discarded
395 * @silent: suppress [true] or print [false] warning messages
396 */
397void nilfs_clear_dirty_page(struct page *page, bool silent)
398{
399 struct inode *inode = page->mapping->host;
400 struct super_block *sb = inode->i_sb;
401
402 BUG_ON(!PageLocked(page));
403
404 if (!silent)
405 nilfs_msg(sb, KERN_WARNING,
406 "discard dirty page: offset=%lld, ino=%lu",
407 page_offset(page), inode->i_ino);
408
409 ClearPageUptodate(page);
410 ClearPageMappedToDisk(page);
411
412 if (page_has_buffers(page)) {
413 struct buffer_head *bh, *head;
414 const unsigned long clear_bits =
415 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
416 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
417 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
418
419 bh = head = page_buffers(page);
420 do {
421 lock_buffer(bh);
422 if (!silent)
423 nilfs_msg(sb, KERN_WARNING,
424 "discard dirty block: blocknr=%llu, size=%zu",
425 (u64)bh->b_blocknr, bh->b_size);
426
427 set_mask_bits(&bh->b_state, clear_bits, 0);
428 unlock_buffer(bh);
429 } while (bh = bh->b_this_page, bh != head);
430 }
431
432 __nilfs_clear_page_dirty(page);
433}
434
435unsigned int nilfs_page_count_clean_buffers(struct page *page,
436 unsigned int from, unsigned int to)
437{
438 unsigned int block_start, block_end;
439 struct buffer_head *bh, *head;
440 unsigned int nc = 0;
441
442 for (bh = head = page_buffers(page), block_start = 0;
443 bh != head || !block_start;
444 block_start = block_end, bh = bh->b_this_page) {
445 block_end = block_start + bh->b_size;
446 if (block_end > from && block_start < to && !buffer_dirty(bh))
447 nc++;
448 }
449 return nc;
450}
451
452void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
453{
454 mapping->host = inode;
455 mapping->flags = 0;
456 mapping_set_gfp_mask(mapping, GFP_NOFS);
457 mapping->private_data = NULL;
458 mapping->a_ops = &empty_aops;
459}
460
461/*
462 * NILFS2 needs clear_page_dirty() in the following two cases:
463 *
464 * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
465 * page dirty flags when it copies back pages from the shadow cache
466 * (gcdat->{i_mapping,i_btnode_cache}) to its original cache
467 * (dat->{i_mapping,i_btnode_cache}).
468 *
469 * 2) Some B-tree operations like insertion or deletion may dispose buffers
470 * in dirty state, and this needs to cancel the dirty state of their pages.
471 */
472int __nilfs_clear_page_dirty(struct page *page)
473{
474 struct address_space *mapping = page->mapping;
475
476 if (mapping) {
477 xa_lock_irq(&mapping->i_pages);
478 if (test_bit(PG_dirty, &page->flags)) {
479 radix_tree_tag_clear(&mapping->i_pages,
480 page_index(page),
481 PAGECACHE_TAG_DIRTY);
482 xa_unlock_irq(&mapping->i_pages);
483 return clear_page_dirty_for_io(page);
484 }
485 xa_unlock_irq(&mapping->i_pages);
486 return 0;
487 }
488 return TestClearPageDirty(page);
489}
490
491/**
492 * nilfs_find_uncommitted_extent - find extent of uncommitted data
493 * @inode: inode
494 * @start_blk: start block offset (in)
495 * @blkoff: start offset of the found extent (out)
496 *
497 * This function searches an extent of buffers marked "delayed" which
498 * starts from a block offset equal to or larger than @start_blk. If
499 * such an extent was found, this will store the start offset in
500 * @blkoff and return its length in blocks. Otherwise, zero is
501 * returned.
502 */
503unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
504 sector_t start_blk,
505 sector_t *blkoff)
506{
507 unsigned int i;
508 pgoff_t index;
509 unsigned int nblocks_in_page;
510 unsigned long length = 0;
511 sector_t b;
512 struct pagevec pvec;
513 struct page *page;
514
515 if (inode->i_mapping->nrpages == 0)
516 return 0;
517
518 index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
519 nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits);
520
521 pagevec_init(&pvec);
522
523repeat:
524 pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
525 pvec.pages);
526 if (pvec.nr == 0)
527 return length;
528
529 if (length > 0 && pvec.pages[0]->index > index)
530 goto out;
531
532 b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits);
533 i = 0;
534 do {
535 page = pvec.pages[i];
536
537 lock_page(page);
538 if (page_has_buffers(page)) {
539 struct buffer_head *bh, *head;
540
541 bh = head = page_buffers(page);
542 do {
543 if (b < start_blk)
544 continue;
545 if (buffer_delay(bh)) {
546 if (length == 0)
547 *blkoff = b;
548 length++;
549 } else if (length > 0) {
550 goto out_locked;
551 }
552 } while (++b, bh = bh->b_this_page, bh != head);
553 } else {
554 if (length > 0)
555 goto out_locked;
556
557 b += nblocks_in_page;
558 }
559 unlock_page(page);
560
561 } while (++i < pagevec_count(&pvec));
562
563 index = page->index + 1;
564 pagevec_release(&pvec);
565 cond_resched();
566 goto repeat;
567
568out_locked:
569 unlock_page(page);
570out:
571 pagevec_release(&pvec);
572 return length;
573}
1/*
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 <linux/gfp.h>
33#include "nilfs.h"
34#include "page.h"
35#include "mdt.h"
36
37
38#define NILFS_BUFFER_INHERENT_BITS \
39 ((1UL << BH_Uptodate) | (1UL << BH_Mapped) | (1UL << BH_NILFS_Node) | \
40 (1UL << BH_NILFS_Volatile) | (1UL << BH_NILFS_Checked))
41
42static struct buffer_head *
43__nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
44 int blkbits, unsigned long b_state)
45
46{
47 unsigned long first_block;
48 struct buffer_head *bh;
49
50 if (!page_has_buffers(page))
51 create_empty_buffers(page, 1 << blkbits, b_state);
52
53 first_block = (unsigned long)index << (PAGE_SHIFT - blkbits);
54 bh = nilfs_page_get_nth_block(page, block - first_block);
55
56 touch_buffer(bh);
57 wait_on_buffer(bh);
58 return bh;
59}
60
61struct buffer_head *nilfs_grab_buffer(struct inode *inode,
62 struct address_space *mapping,
63 unsigned long blkoff,
64 unsigned long b_state)
65{
66 int blkbits = inode->i_blkbits;
67 pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits);
68 struct page *page;
69 struct buffer_head *bh;
70
71 page = grab_cache_page(mapping, index);
72 if (unlikely(!page))
73 return NULL;
74
75 bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
76 if (unlikely(!bh)) {
77 unlock_page(page);
78 put_page(page);
79 return NULL;
80 }
81 return bh;
82}
83
84/**
85 * nilfs_forget_buffer - discard dirty state
86 * @inode: owner inode of the buffer
87 * @bh: buffer head of the buffer to be discarded
88 */
89void nilfs_forget_buffer(struct buffer_head *bh)
90{
91 struct page *page = bh->b_page;
92 const unsigned long clear_bits =
93 (1 << BH_Uptodate | 1 << BH_Dirty | 1 << BH_Mapped |
94 1 << BH_Async_Write | 1 << BH_NILFS_Volatile |
95 1 << BH_NILFS_Checked | 1 << BH_NILFS_Redirected);
96
97 lock_buffer(bh);
98 set_mask_bits(&bh->b_state, clear_bits, 0);
99 if (nilfs_page_buffers_clean(page))
100 __nilfs_clear_page_dirty(page);
101
102 bh->b_blocknr = -1;
103 ClearPageUptodate(page);
104 ClearPageMappedToDisk(page);
105 unlock_buffer(bh);
106 brelse(bh);
107}
108
109/**
110 * nilfs_copy_buffer -- copy buffer data and flags
111 * @dbh: destination buffer
112 * @sbh: source buffer
113 */
114void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
115{
116 void *kaddr0, *kaddr1;
117 unsigned long bits;
118 struct page *spage = sbh->b_page, *dpage = dbh->b_page;
119 struct buffer_head *bh;
120
121 kaddr0 = kmap_atomic(spage);
122 kaddr1 = kmap_atomic(dpage);
123 memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
124 kunmap_atomic(kaddr1);
125 kunmap_atomic(kaddr0);
126
127 dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
128 dbh->b_blocknr = sbh->b_blocknr;
129 dbh->b_bdev = sbh->b_bdev;
130
131 bh = dbh;
132 bits = sbh->b_state & ((1UL << BH_Uptodate) | (1UL << BH_Mapped));
133 while ((bh = bh->b_this_page) != dbh) {
134 lock_buffer(bh);
135 bits &= bh->b_state;
136 unlock_buffer(bh);
137 }
138 if (bits & (1UL << BH_Uptodate))
139 SetPageUptodate(dpage);
140 else
141 ClearPageUptodate(dpage);
142 if (bits & (1UL << BH_Mapped))
143 SetPageMappedToDisk(dpage);
144 else
145 ClearPageMappedToDisk(dpage);
146}
147
148/**
149 * nilfs_page_buffers_clean - check if a page has dirty buffers or not.
150 * @page: page to be checked
151 *
152 * nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
153 * Otherwise, it returns non-zero value.
154 */
155int nilfs_page_buffers_clean(struct page *page)
156{
157 struct buffer_head *bh, *head;
158
159 bh = head = page_buffers(page);
160 do {
161 if (buffer_dirty(bh))
162 return 0;
163 bh = bh->b_this_page;
164 } while (bh != head);
165 return 1;
166}
167
168void nilfs_page_bug(struct page *page)
169{
170 struct address_space *m;
171 unsigned long ino;
172
173 if (unlikely(!page)) {
174 printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
175 return;
176 }
177
178 m = page->mapping;
179 ino = m ? m->host->i_ino : 0;
180
181 printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
182 "mapping=%p ino=%lu\n",
183 page, page_ref_count(page),
184 (unsigned long long)page->index, page->flags, m, ino);
185
186 if (page_has_buffers(page)) {
187 struct buffer_head *bh, *head;
188 int i = 0;
189
190 bh = head = page_buffers(page);
191 do {
192 printk(KERN_CRIT
193 " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
194 i++, bh, atomic_read(&bh->b_count),
195 (unsigned long long)bh->b_blocknr, bh->b_state);
196 bh = bh->b_this_page;
197 } while (bh != head);
198 }
199}
200
201/**
202 * nilfs_copy_page -- copy the page with buffers
203 * @dst: destination page
204 * @src: source page
205 * @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
206 *
207 * This function is for both data pages and btnode pages. The dirty flag
208 * should be treated by caller. The page must not be under i/o.
209 * Both src and dst page must be locked
210 */
211static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
212{
213 struct buffer_head *dbh, *dbufs, *sbh, *sbufs;
214 unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
215
216 BUG_ON(PageWriteback(dst));
217
218 sbh = sbufs = page_buffers(src);
219 if (!page_has_buffers(dst))
220 create_empty_buffers(dst, sbh->b_size, 0);
221
222 if (copy_dirty)
223 mask |= (1UL << BH_Dirty);
224
225 dbh = dbufs = page_buffers(dst);
226 do {
227 lock_buffer(sbh);
228 lock_buffer(dbh);
229 dbh->b_state = sbh->b_state & mask;
230 dbh->b_blocknr = sbh->b_blocknr;
231 dbh->b_bdev = sbh->b_bdev;
232 sbh = sbh->b_this_page;
233 dbh = dbh->b_this_page;
234 } while (dbh != dbufs);
235
236 copy_highpage(dst, src);
237
238 if (PageUptodate(src) && !PageUptodate(dst))
239 SetPageUptodate(dst);
240 else if (!PageUptodate(src) && PageUptodate(dst))
241 ClearPageUptodate(dst);
242 if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
243 SetPageMappedToDisk(dst);
244 else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
245 ClearPageMappedToDisk(dst);
246
247 do {
248 unlock_buffer(sbh);
249 unlock_buffer(dbh);
250 sbh = sbh->b_this_page;
251 dbh = dbh->b_this_page;
252 } while (dbh != dbufs);
253}
254
255int nilfs_copy_dirty_pages(struct address_space *dmap,
256 struct address_space *smap)
257{
258 struct pagevec pvec;
259 unsigned int i;
260 pgoff_t index = 0;
261 int err = 0;
262
263 pagevec_init(&pvec, 0);
264repeat:
265 if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY,
266 PAGEVEC_SIZE))
267 return 0;
268
269 for (i = 0; i < pagevec_count(&pvec); i++) {
270 struct page *page = pvec.pages[i], *dpage;
271
272 lock_page(page);
273 if (unlikely(!PageDirty(page)))
274 NILFS_PAGE_BUG(page, "inconsistent dirty state");
275
276 dpage = grab_cache_page(dmap, page->index);
277 if (unlikely(!dpage)) {
278 /* No empty page is added to the page cache */
279 err = -ENOMEM;
280 unlock_page(page);
281 break;
282 }
283 if (unlikely(!page_has_buffers(page)))
284 NILFS_PAGE_BUG(page,
285 "found empty page in dat page cache");
286
287 nilfs_copy_page(dpage, page, 1);
288 __set_page_dirty_nobuffers(dpage);
289
290 unlock_page(dpage);
291 put_page(dpage);
292 unlock_page(page);
293 }
294 pagevec_release(&pvec);
295 cond_resched();
296
297 if (likely(!err))
298 goto repeat;
299 return err;
300}
301
302/**
303 * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
304 * @dmap: destination page cache
305 * @smap: source page cache
306 *
307 * No pages must no be added to the cache during this process.
308 * This must be ensured by the caller.
309 */
310void nilfs_copy_back_pages(struct address_space *dmap,
311 struct address_space *smap)
312{
313 struct pagevec pvec;
314 unsigned int i, n;
315 pgoff_t index = 0;
316 int err;
317
318 pagevec_init(&pvec, 0);
319repeat:
320 n = pagevec_lookup(&pvec, smap, index, PAGEVEC_SIZE);
321 if (!n)
322 return;
323 index = pvec.pages[n - 1]->index + 1;
324
325 for (i = 0; i < pagevec_count(&pvec); i++) {
326 struct page *page = pvec.pages[i], *dpage;
327 pgoff_t offset = page->index;
328
329 lock_page(page);
330 dpage = find_lock_page(dmap, offset);
331 if (dpage) {
332 /* override existing page on the destination cache */
333 WARN_ON(PageDirty(dpage));
334 nilfs_copy_page(dpage, page, 0);
335 unlock_page(dpage);
336 put_page(dpage);
337 } else {
338 struct page *page2;
339
340 /* move the page to the destination cache */
341 spin_lock_irq(&smap->tree_lock);
342 page2 = radix_tree_delete(&smap->page_tree, offset);
343 WARN_ON(page2 != page);
344
345 smap->nrpages--;
346 spin_unlock_irq(&smap->tree_lock);
347
348 spin_lock_irq(&dmap->tree_lock);
349 err = radix_tree_insert(&dmap->page_tree, offset, page);
350 if (unlikely(err < 0)) {
351 WARN_ON(err == -EEXIST);
352 page->mapping = NULL;
353 put_page(page); /* for cache */
354 } else {
355 page->mapping = dmap;
356 dmap->nrpages++;
357 if (PageDirty(page))
358 radix_tree_tag_set(&dmap->page_tree,
359 offset,
360 PAGECACHE_TAG_DIRTY);
361 }
362 spin_unlock_irq(&dmap->tree_lock);
363 }
364 unlock_page(page);
365 }
366 pagevec_release(&pvec);
367 cond_resched();
368
369 goto repeat;
370}
371
372/**
373 * nilfs_clear_dirty_pages - discard dirty pages in address space
374 * @mapping: address space with dirty pages for discarding
375 * @silent: suppress [true] or print [false] warning messages
376 */
377void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
378{
379 struct pagevec pvec;
380 unsigned int i;
381 pgoff_t index = 0;
382
383 pagevec_init(&pvec, 0);
384
385 while (pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY,
386 PAGEVEC_SIZE)) {
387 for (i = 0; i < pagevec_count(&pvec); i++) {
388 struct page *page = pvec.pages[i];
389
390 lock_page(page);
391 nilfs_clear_dirty_page(page, silent);
392 unlock_page(page);
393 }
394 pagevec_release(&pvec);
395 cond_resched();
396 }
397}
398
399/**
400 * nilfs_clear_dirty_page - discard dirty page
401 * @page: dirty page that will be discarded
402 * @silent: suppress [true] or print [false] warning messages
403 */
404void nilfs_clear_dirty_page(struct page *page, bool silent)
405{
406 struct inode *inode = page->mapping->host;
407 struct super_block *sb = inode->i_sb;
408
409 BUG_ON(!PageLocked(page));
410
411 if (!silent) {
412 nilfs_warning(sb, __func__,
413 "discard page: offset %lld, ino %lu",
414 page_offset(page), inode->i_ino);
415 }
416
417 ClearPageUptodate(page);
418 ClearPageMappedToDisk(page);
419
420 if (page_has_buffers(page)) {
421 struct buffer_head *bh, *head;
422 const unsigned long clear_bits =
423 (1 << BH_Uptodate | 1 << BH_Dirty | 1 << BH_Mapped |
424 1 << BH_Async_Write | 1 << BH_NILFS_Volatile |
425 1 << BH_NILFS_Checked | 1 << BH_NILFS_Redirected);
426
427 bh = head = page_buffers(page);
428 do {
429 lock_buffer(bh);
430 if (!silent) {
431 nilfs_warning(sb, __func__,
432 "discard block %llu, size %zu",
433 (u64)bh->b_blocknr, bh->b_size);
434 }
435 set_mask_bits(&bh->b_state, clear_bits, 0);
436 unlock_buffer(bh);
437 } while (bh = bh->b_this_page, bh != head);
438 }
439
440 __nilfs_clear_page_dirty(page);
441}
442
443unsigned nilfs_page_count_clean_buffers(struct page *page,
444 unsigned from, unsigned to)
445{
446 unsigned block_start, block_end;
447 struct buffer_head *bh, *head;
448 unsigned nc = 0;
449
450 for (bh = head = page_buffers(page), block_start = 0;
451 bh != head || !block_start;
452 block_start = block_end, bh = bh->b_this_page) {
453 block_end = block_start + bh->b_size;
454 if (block_end > from && block_start < to && !buffer_dirty(bh))
455 nc++;
456 }
457 return nc;
458}
459
460void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
461{
462 mapping->host = inode;
463 mapping->flags = 0;
464 mapping_set_gfp_mask(mapping, GFP_NOFS);
465 mapping->private_data = NULL;
466 mapping->a_ops = &empty_aops;
467}
468
469/*
470 * NILFS2 needs clear_page_dirty() in the following two cases:
471 *
472 * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
473 * page dirty flags when it copies back pages from the shadow cache
474 * (gcdat->{i_mapping,i_btnode_cache}) to its original cache
475 * (dat->{i_mapping,i_btnode_cache}).
476 *
477 * 2) Some B-tree operations like insertion or deletion may dispose buffers
478 * in dirty state, and this needs to cancel the dirty state of their pages.
479 */
480int __nilfs_clear_page_dirty(struct page *page)
481{
482 struct address_space *mapping = page->mapping;
483
484 if (mapping) {
485 spin_lock_irq(&mapping->tree_lock);
486 if (test_bit(PG_dirty, &page->flags)) {
487 radix_tree_tag_clear(&mapping->page_tree,
488 page_index(page),
489 PAGECACHE_TAG_DIRTY);
490 spin_unlock_irq(&mapping->tree_lock);
491 return clear_page_dirty_for_io(page);
492 }
493 spin_unlock_irq(&mapping->tree_lock);
494 return 0;
495 }
496 return TestClearPageDirty(page);
497}
498
499/**
500 * nilfs_find_uncommitted_extent - find extent of uncommitted data
501 * @inode: inode
502 * @start_blk: start block offset (in)
503 * @blkoff: start offset of the found extent (out)
504 *
505 * This function searches an extent of buffers marked "delayed" which
506 * starts from a block offset equal to or larger than @start_blk. If
507 * such an extent was found, this will store the start offset in
508 * @blkoff and return its length in blocks. Otherwise, zero is
509 * returned.
510 */
511unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
512 sector_t start_blk,
513 sector_t *blkoff)
514{
515 unsigned int i;
516 pgoff_t index;
517 unsigned int nblocks_in_page;
518 unsigned long length = 0;
519 sector_t b;
520 struct pagevec pvec;
521 struct page *page;
522
523 if (inode->i_mapping->nrpages == 0)
524 return 0;
525
526 index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
527 nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits);
528
529 pagevec_init(&pvec, 0);
530
531repeat:
532 pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
533 pvec.pages);
534 if (pvec.nr == 0)
535 return length;
536
537 if (length > 0 && pvec.pages[0]->index > index)
538 goto out;
539
540 b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits);
541 i = 0;
542 do {
543 page = pvec.pages[i];
544
545 lock_page(page);
546 if (page_has_buffers(page)) {
547 struct buffer_head *bh, *head;
548
549 bh = head = page_buffers(page);
550 do {
551 if (b < start_blk)
552 continue;
553 if (buffer_delay(bh)) {
554 if (length == 0)
555 *blkoff = b;
556 length++;
557 } else if (length > 0) {
558 goto out_locked;
559 }
560 } while (++b, bh = bh->b_this_page, bh != head);
561 } else {
562 if (length > 0)
563 goto out_locked;
564
565 b += nblocks_in_page;
566 }
567 unlock_page(page);
568
569 } while (++i < pagevec_count(&pvec));
570
571 index = page->index + 1;
572 pagevec_release(&pvec);
573 cond_resched();
574 goto repeat;
575
576out_locked:
577 unlock_page(page);
578out:
579 pagevec_release(&pvec);
580 return length;
581}