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