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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Buffer/page management specific to NILFS
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Written by Ryusuke Konishi and Seiji Kihara.
8 */
9
10#include <linux/pagemap.h>
11#include <linux/writeback.h>
12#include <linux/swap.h>
13#include <linux/bitops.h>
14#include <linux/page-flags.h>
15#include <linux/list.h>
16#include <linux/highmem.h>
17#include <linux/pagevec.h>
18#include <linux/gfp.h>
19#include "nilfs.h"
20#include "page.h"
21#include "mdt.h"
22
23
24#define NILFS_BUFFER_INHERENT_BITS \
25 (BIT(BH_Uptodate) | BIT(BH_Mapped) | BIT(BH_NILFS_Node) | \
26 BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Checked))
27
28static struct buffer_head *
29__nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
30 int blkbits, unsigned long b_state)
31
32{
33 unsigned long first_block;
34 struct buffer_head *bh;
35
36 if (!page_has_buffers(page))
37 create_empty_buffers(page, 1 << blkbits, b_state);
38
39 first_block = (unsigned long)index << (PAGE_SHIFT - blkbits);
40 bh = nilfs_page_get_nth_block(page, block - first_block);
41
42 touch_buffer(bh);
43 wait_on_buffer(bh);
44 return bh;
45}
46
47struct buffer_head *nilfs_grab_buffer(struct inode *inode,
48 struct address_space *mapping,
49 unsigned long blkoff,
50 unsigned long b_state)
51{
52 int blkbits = inode->i_blkbits;
53 pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits);
54 struct page *page;
55 struct buffer_head *bh;
56
57 page = grab_cache_page(mapping, index);
58 if (unlikely(!page))
59 return NULL;
60
61 bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
62 if (unlikely(!bh)) {
63 unlock_page(page);
64 put_page(page);
65 return NULL;
66 }
67 return bh;
68}
69
70/**
71 * nilfs_forget_buffer - discard dirty state
72 * @bh: buffer head of the buffer to be discarded
73 */
74void nilfs_forget_buffer(struct buffer_head *bh)
75{
76 struct page *page = bh->b_page;
77 const unsigned long clear_bits =
78 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
79 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
80 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
81
82 lock_buffer(bh);
83 set_mask_bits(&bh->b_state, clear_bits, 0);
84 if (nilfs_page_buffers_clean(page))
85 __nilfs_clear_page_dirty(page);
86
87 bh->b_blocknr = -1;
88 ClearPageUptodate(page);
89 ClearPageMappedToDisk(page);
90 unlock_buffer(bh);
91 brelse(bh);
92}
93
94/**
95 * nilfs_copy_buffer -- copy buffer data and flags
96 * @dbh: destination buffer
97 * @sbh: source buffer
98 */
99void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
100{
101 void *kaddr0, *kaddr1;
102 unsigned long bits;
103 struct page *spage = sbh->b_page, *dpage = dbh->b_page;
104 struct buffer_head *bh;
105
106 kaddr0 = kmap_atomic(spage);
107 kaddr1 = kmap_atomic(dpage);
108 memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
109 kunmap_atomic(kaddr1);
110 kunmap_atomic(kaddr0);
111
112 dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
113 dbh->b_blocknr = sbh->b_blocknr;
114 dbh->b_bdev = sbh->b_bdev;
115
116 bh = dbh;
117 bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped));
118 while ((bh = bh->b_this_page) != dbh) {
119 lock_buffer(bh);
120 bits &= bh->b_state;
121 unlock_buffer(bh);
122 }
123 if (bits & BIT(BH_Uptodate))
124 SetPageUptodate(dpage);
125 else
126 ClearPageUptodate(dpage);
127 if (bits & BIT(BH_Mapped))
128 SetPageMappedToDisk(dpage);
129 else
130 ClearPageMappedToDisk(dpage);
131}
132
133/**
134 * nilfs_page_buffers_clean - check if a page has dirty buffers or not.
135 * @page: page to be checked
136 *
137 * nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
138 * Otherwise, it returns non-zero value.
139 */
140int nilfs_page_buffers_clean(struct page *page)
141{
142 struct buffer_head *bh, *head;
143
144 bh = head = page_buffers(page);
145 do {
146 if (buffer_dirty(bh))
147 return 0;
148 bh = bh->b_this_page;
149 } while (bh != head);
150 return 1;
151}
152
153void nilfs_page_bug(struct page *page)
154{
155 struct address_space *m;
156 unsigned long ino;
157
158 if (unlikely(!page)) {
159 printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
160 return;
161 }
162
163 m = page->mapping;
164 ino = m ? m->host->i_ino : 0;
165
166 printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
167 "mapping=%p ino=%lu\n",
168 page, page_ref_count(page),
169 (unsigned long long)page->index, page->flags, m, ino);
170
171 if (page_has_buffers(page)) {
172 struct buffer_head *bh, *head;
173 int i = 0;
174
175 bh = head = page_buffers(page);
176 do {
177 printk(KERN_CRIT
178 " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
179 i++, bh, atomic_read(&bh->b_count),
180 (unsigned long long)bh->b_blocknr, bh->b_state);
181 bh = bh->b_this_page;
182 } while (bh != head);
183 }
184}
185
186/**
187 * nilfs_copy_page -- copy the page with buffers
188 * @dst: destination page
189 * @src: source page
190 * @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
191 *
192 * This function is for both data pages and btnode pages. The dirty flag
193 * should be treated by caller. The page must not be under i/o.
194 * Both src and dst page must be locked
195 */
196static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
197{
198 struct buffer_head *dbh, *dbufs, *sbh;
199 unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
200
201 BUG_ON(PageWriteback(dst));
202
203 sbh = page_buffers(src);
204 if (!page_has_buffers(dst))
205 create_empty_buffers(dst, sbh->b_size, 0);
206
207 if (copy_dirty)
208 mask |= BIT(BH_Dirty);
209
210 dbh = dbufs = page_buffers(dst);
211 do {
212 lock_buffer(sbh);
213 lock_buffer(dbh);
214 dbh->b_state = sbh->b_state & mask;
215 dbh->b_blocknr = sbh->b_blocknr;
216 dbh->b_bdev = sbh->b_bdev;
217 sbh = sbh->b_this_page;
218 dbh = dbh->b_this_page;
219 } while (dbh != dbufs);
220
221 copy_highpage(dst, src);
222
223 if (PageUptodate(src) && !PageUptodate(dst))
224 SetPageUptodate(dst);
225 else if (!PageUptodate(src) && PageUptodate(dst))
226 ClearPageUptodate(dst);
227 if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
228 SetPageMappedToDisk(dst);
229 else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
230 ClearPageMappedToDisk(dst);
231
232 do {
233 unlock_buffer(sbh);
234 unlock_buffer(dbh);
235 sbh = sbh->b_this_page;
236 dbh = dbh->b_this_page;
237 } while (dbh != dbufs);
238}
239
240int nilfs_copy_dirty_pages(struct address_space *dmap,
241 struct address_space *smap)
242{
243 struct pagevec pvec;
244 unsigned int i;
245 pgoff_t index = 0;
246 int err = 0;
247
248 pagevec_init(&pvec);
249repeat:
250 if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY))
251 return 0;
252
253 for (i = 0; i < pagevec_count(&pvec); i++) {
254 struct page *page = pvec.pages[i], *dpage;
255
256 lock_page(page);
257 if (unlikely(!PageDirty(page)))
258 NILFS_PAGE_BUG(page, "inconsistent dirty state");
259
260 dpage = grab_cache_page(dmap, page->index);
261 if (unlikely(!dpage)) {
262 /* No empty page is added to the page cache */
263 err = -ENOMEM;
264 unlock_page(page);
265 break;
266 }
267 if (unlikely(!page_has_buffers(page)))
268 NILFS_PAGE_BUG(page,
269 "found empty page in dat page cache");
270
271 nilfs_copy_page(dpage, page, 1);
272 __set_page_dirty_nobuffers(dpage);
273
274 unlock_page(dpage);
275 put_page(dpage);
276 unlock_page(page);
277 }
278 pagevec_release(&pvec);
279 cond_resched();
280
281 if (likely(!err))
282 goto repeat;
283 return err;
284}
285
286/**
287 * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
288 * @dmap: destination page cache
289 * @smap: source page cache
290 *
291 * No pages must be added to the cache during this process.
292 * This must be ensured by the caller.
293 */
294void nilfs_copy_back_pages(struct address_space *dmap,
295 struct address_space *smap)
296{
297 struct folio_batch fbatch;
298 unsigned int i, n;
299 pgoff_t start = 0;
300
301 folio_batch_init(&fbatch);
302repeat:
303 n = filemap_get_folios(smap, &start, ~0UL, &fbatch);
304 if (!n)
305 return;
306
307 for (i = 0; i < folio_batch_count(&fbatch); i++) {
308 struct folio *folio = fbatch.folios[i], *dfolio;
309 pgoff_t index = folio->index;
310
311 folio_lock(folio);
312 dfolio = filemap_lock_folio(dmap, index);
313 if (dfolio) {
314 /* overwrite existing folio in the destination cache */
315 WARN_ON(folio_test_dirty(dfolio));
316 nilfs_copy_page(&dfolio->page, &folio->page, 0);
317 folio_unlock(dfolio);
318 folio_put(dfolio);
319 /* Do we not need to remove folio from smap here? */
320 } else {
321 struct folio *f;
322
323 /* move the folio to the destination cache */
324 xa_lock_irq(&smap->i_pages);
325 f = __xa_erase(&smap->i_pages, index);
326 WARN_ON(folio != f);
327 smap->nrpages--;
328 xa_unlock_irq(&smap->i_pages);
329
330 xa_lock_irq(&dmap->i_pages);
331 f = __xa_store(&dmap->i_pages, index, folio, GFP_NOFS);
332 if (unlikely(f)) {
333 /* Probably -ENOMEM */
334 folio->mapping = NULL;
335 folio_put(folio);
336 } else {
337 folio->mapping = dmap;
338 dmap->nrpages++;
339 if (folio_test_dirty(folio))
340 __xa_set_mark(&dmap->i_pages, index,
341 PAGECACHE_TAG_DIRTY);
342 }
343 xa_unlock_irq(&dmap->i_pages);
344 }
345 folio_unlock(folio);
346 }
347 folio_batch_release(&fbatch);
348 cond_resched();
349
350 goto repeat;
351}
352
353/**
354 * nilfs_clear_dirty_pages - discard dirty pages in address space
355 * @mapping: address space with dirty pages for discarding
356 * @silent: suppress [true] or print [false] warning messages
357 */
358void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
359{
360 struct pagevec pvec;
361 unsigned int i;
362 pgoff_t index = 0;
363
364 pagevec_init(&pvec);
365
366 while (pagevec_lookup_tag(&pvec, mapping, &index,
367 PAGECACHE_TAG_DIRTY)) {
368 for (i = 0; i < pagevec_count(&pvec); i++) {
369 struct page *page = pvec.pages[i];
370
371 lock_page(page);
372 nilfs_clear_dirty_page(page, silent);
373 unlock_page(page);
374 }
375 pagevec_release(&pvec);
376 cond_resched();
377 }
378}
379
380/**
381 * nilfs_clear_dirty_page - discard dirty page
382 * @page: dirty page that will be discarded
383 * @silent: suppress [true] or print [false] warning messages
384 */
385void nilfs_clear_dirty_page(struct page *page, bool silent)
386{
387 struct inode *inode = page->mapping->host;
388 struct super_block *sb = inode->i_sb;
389
390 BUG_ON(!PageLocked(page));
391
392 if (!silent)
393 nilfs_warn(sb, "discard dirty page: offset=%lld, ino=%lu",
394 page_offset(page), inode->i_ino);
395
396 ClearPageUptodate(page);
397 ClearPageMappedToDisk(page);
398
399 if (page_has_buffers(page)) {
400 struct buffer_head *bh, *head;
401 const unsigned long clear_bits =
402 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
403 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
404 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
405
406 bh = head = page_buffers(page);
407 do {
408 lock_buffer(bh);
409 if (!silent)
410 nilfs_warn(sb,
411 "discard dirty block: blocknr=%llu, size=%zu",
412 (u64)bh->b_blocknr, bh->b_size);
413
414 set_mask_bits(&bh->b_state, clear_bits, 0);
415 unlock_buffer(bh);
416 } while (bh = bh->b_this_page, bh != head);
417 }
418
419 __nilfs_clear_page_dirty(page);
420}
421
422unsigned int nilfs_page_count_clean_buffers(struct page *page,
423 unsigned int from, unsigned int to)
424{
425 unsigned int block_start, block_end;
426 struct buffer_head *bh, *head;
427 unsigned int nc = 0;
428
429 for (bh = head = page_buffers(page), block_start = 0;
430 bh != head || !block_start;
431 block_start = block_end, bh = bh->b_this_page) {
432 block_end = block_start + bh->b_size;
433 if (block_end > from && block_start < to && !buffer_dirty(bh))
434 nc++;
435 }
436 return nc;
437}
438
439/*
440 * NILFS2 needs clear_page_dirty() in the following two cases:
441 *
442 * 1) For B-tree node pages and data pages of DAT file, NILFS2 clears dirty
443 * flag of pages when it copies back pages from shadow cache to the
444 * original cache.
445 *
446 * 2) Some B-tree operations like insertion or deletion may dispose buffers
447 * in dirty state, and this needs to cancel the dirty state of their pages.
448 */
449int __nilfs_clear_page_dirty(struct page *page)
450{
451 struct address_space *mapping = page->mapping;
452
453 if (mapping) {
454 xa_lock_irq(&mapping->i_pages);
455 if (test_bit(PG_dirty, &page->flags)) {
456 __xa_clear_mark(&mapping->i_pages, page_index(page),
457 PAGECACHE_TAG_DIRTY);
458 xa_unlock_irq(&mapping->i_pages);
459 return clear_page_dirty_for_io(page);
460 }
461 xa_unlock_irq(&mapping->i_pages);
462 return 0;
463 }
464 return TestClearPageDirty(page);
465}
466
467/**
468 * nilfs_find_uncommitted_extent - find extent of uncommitted data
469 * @inode: inode
470 * @start_blk: start block offset (in)
471 * @blkoff: start offset of the found extent (out)
472 *
473 * This function searches an extent of buffers marked "delayed" which
474 * starts from a block offset equal to or larger than @start_blk. If
475 * such an extent was found, this will store the start offset in
476 * @blkoff and return its length in blocks. Otherwise, zero is
477 * returned.
478 */
479unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
480 sector_t start_blk,
481 sector_t *blkoff)
482{
483 unsigned int i, nr_folios;
484 pgoff_t index;
485 unsigned long length = 0;
486 struct folio_batch fbatch;
487 struct folio *folio;
488
489 if (inode->i_mapping->nrpages == 0)
490 return 0;
491
492 index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
493
494 folio_batch_init(&fbatch);
495
496repeat:
497 nr_folios = filemap_get_folios_contig(inode->i_mapping, &index, ULONG_MAX,
498 &fbatch);
499 if (nr_folios == 0)
500 return length;
501
502 i = 0;
503 do {
504 folio = fbatch.folios[i];
505
506 folio_lock(folio);
507 if (folio_buffers(folio)) {
508 struct buffer_head *bh, *head;
509 sector_t b;
510
511 b = folio->index << (PAGE_SHIFT - inode->i_blkbits);
512 bh = head = folio_buffers(folio);
513 do {
514 if (b < start_blk)
515 continue;
516 if (buffer_delay(bh)) {
517 if (length == 0)
518 *blkoff = b;
519 length++;
520 } else if (length > 0) {
521 goto out_locked;
522 }
523 } while (++b, bh = bh->b_this_page, bh != head);
524 } else {
525 if (length > 0)
526 goto out_locked;
527 }
528 folio_unlock(folio);
529
530 } while (++i < nr_folios);
531
532 folio_batch_release(&fbatch);
533 cond_resched();
534 goto repeat;
535
536out_locked:
537 folio_unlock(folio);
538 folio_batch_release(&fbatch);
539 return length;
540}
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}