1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * page.c - 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
28 static struct buffer_head *
__nilfs_get_page_block(struct page * page,unsigned long block,pgoff_t index,int blkbits,unsigned long b_state)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
nilfs_grab_buffer(struct inode * inode,struct address_space * mapping,unsigned long blkoff,unsigned long b_state)47 struct 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 * @inode: owner inode of the buffer
73 * @bh: buffer head of the buffer to be discarded
74 */
nilfs_forget_buffer(struct buffer_head * bh)75 void nilfs_forget_buffer(struct buffer_head *bh)
76 {
77 struct page *page = bh->b_page;
78 const unsigned long clear_bits =
79 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
80 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
81 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
82
83 lock_buffer(bh);
84 set_mask_bits(&bh->b_state, clear_bits, 0);
85 if (nilfs_page_buffers_clean(page))
86 __nilfs_clear_page_dirty(page);
87
88 bh->b_blocknr = -1;
89 ClearPageUptodate(page);
90 ClearPageMappedToDisk(page);
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 */
nilfs_copy_buffer(struct buffer_head * dbh,struct buffer_head * sbh)100 void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
101 {
102 void *kaddr0, *kaddr1;
103 unsigned long bits;
104 struct page *spage = sbh->b_page, *dpage = dbh->b_page;
105 struct buffer_head *bh;
106
107 kaddr0 = kmap_atomic(spage);
108 kaddr1 = kmap_atomic(dpage);
109 memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
110 kunmap_atomic(kaddr1);
111 kunmap_atomic(kaddr0);
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 SetPageUptodate(dpage);
126 else
127 ClearPageUptodate(dpage);
128 if (bits & BIT(BH_Mapped))
129 SetPageMappedToDisk(dpage);
130 else
131 ClearPageMappedToDisk(dpage);
132 }
133
134 /**
135 * nilfs_page_buffers_clean - check if a page has dirty buffers or not.
136 * @page: page to be checked
137 *
138 * nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
139 * Otherwise, it returns non-zero value.
140 */
nilfs_page_buffers_clean(struct page * page)141 int nilfs_page_buffers_clean(struct page *page)
142 {
143 struct buffer_head *bh, *head;
144
145 bh = head = page_buffers(page);
146 do {
147 if (buffer_dirty(bh))
148 return 0;
149 bh = bh->b_this_page;
150 } while (bh != head);
151 return 1;
152 }
153
nilfs_page_bug(struct page * page)154 void nilfs_page_bug(struct page *page)
155 {
156 struct address_space *m;
157 unsigned long ino;
158
159 if (unlikely(!page)) {
160 printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
161 return;
162 }
163
164 m = page->mapping;
165 ino = m ? m->host->i_ino : 0;
166
167 printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
168 "mapping=%p ino=%lu\n",
169 page, page_ref_count(page),
170 (unsigned long long)page->index, page->flags, m, ino);
171
172 if (page_has_buffers(page)) {
173 struct buffer_head *bh, *head;
174 int i = 0;
175
176 bh = head = page_buffers(page);
177 do {
178 printk(KERN_CRIT
179 " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
180 i++, bh, atomic_read(&bh->b_count),
181 (unsigned long long)bh->b_blocknr, bh->b_state);
182 bh = bh->b_this_page;
183 } while (bh != head);
184 }
185 }
186
187 /**
188 * nilfs_copy_page -- copy the page with buffers
189 * @dst: destination page
190 * @src: source page
191 * @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
192 *
193 * This function is for both data pages and btnode pages. The dirty flag
194 * should be treated by caller. The page must not be under i/o.
195 * Both src and dst page must be locked
196 */
nilfs_copy_page(struct page * dst,struct page * src,int copy_dirty)197 static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
198 {
199 struct buffer_head *dbh, *dbufs, *sbh, *sbufs;
200 unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
201
202 BUG_ON(PageWriteback(dst));
203
204 sbh = sbufs = page_buffers(src);
205 if (!page_has_buffers(dst))
206 create_empty_buffers(dst, sbh->b_size, 0);
207
208 if (copy_dirty)
209 mask |= BIT(BH_Dirty);
210
211 dbh = dbufs = page_buffers(dst);
212 do {
213 lock_buffer(sbh);
214 lock_buffer(dbh);
215 dbh->b_state = sbh->b_state & mask;
216 dbh->b_blocknr = sbh->b_blocknr;
217 dbh->b_bdev = sbh->b_bdev;
218 sbh = sbh->b_this_page;
219 dbh = dbh->b_this_page;
220 } while (dbh != dbufs);
221
222 copy_highpage(dst, src);
223
224 if (PageUptodate(src) && !PageUptodate(dst))
225 SetPageUptodate(dst);
226 else if (!PageUptodate(src) && PageUptodate(dst))
227 ClearPageUptodate(dst);
228 if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
229 SetPageMappedToDisk(dst);
230 else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
231 ClearPageMappedToDisk(dst);
232
233 do {
234 unlock_buffer(sbh);
235 unlock_buffer(dbh);
236 sbh = sbh->b_this_page;
237 dbh = dbh->b_this_page;
238 } while (dbh != dbufs);
239 }
240
nilfs_copy_dirty_pages(struct address_space * dmap,struct address_space * smap)241 int nilfs_copy_dirty_pages(struct address_space *dmap,
242 struct address_space *smap)
243 {
244 struct pagevec pvec;
245 unsigned int i;
246 pgoff_t index = 0;
247 int err = 0;
248
249 pagevec_init(&pvec);
250 repeat:
251 if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY))
252 return 0;
253
254 for (i = 0; i < pagevec_count(&pvec); i++) {
255 struct page *page = pvec.pages[i], *dpage;
256
257 lock_page(page);
258 if (unlikely(!PageDirty(page)))
259 NILFS_PAGE_BUG(page, "inconsistent dirty state");
260
261 dpage = grab_cache_page(dmap, page->index);
262 if (unlikely(!dpage)) {
263 /* No empty page is added to the page cache */
264 err = -ENOMEM;
265 unlock_page(page);
266 break;
267 }
268 if (unlikely(!page_has_buffers(page)))
269 NILFS_PAGE_BUG(page,
270 "found empty page in dat page cache");
271
272 nilfs_copy_page(dpage, page, 1);
273 __set_page_dirty_nobuffers(dpage);
274
275 unlock_page(dpage);
276 put_page(dpage);
277 unlock_page(page);
278 }
279 pagevec_release(&pvec);
280 cond_resched();
281
282 if (likely(!err))
283 goto repeat;
284 return err;
285 }
286
287 /**
288 * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
289 * @dmap: destination page cache
290 * @smap: source page cache
291 *
292 * No pages must be added to the cache during this process.
293 * This must be ensured by the caller.
294 */
nilfs_copy_back_pages(struct address_space * dmap,struct address_space * smap)295 void nilfs_copy_back_pages(struct address_space *dmap,
296 struct address_space *smap)
297 {
298 struct pagevec pvec;
299 unsigned int i, n;
300 pgoff_t index = 0;
301
302 pagevec_init(&pvec);
303 repeat:
304 n = pagevec_lookup(&pvec, smap, &index);
305 if (!n)
306 return;
307
308 for (i = 0; i < pagevec_count(&pvec); i++) {
309 struct page *page = pvec.pages[i], *dpage;
310 pgoff_t offset = page->index;
311
312 lock_page(page);
313 dpage = find_lock_page(dmap, offset);
314 if (dpage) {
315 /* overwrite existing page in the destination cache */
316 WARN_ON(PageDirty(dpage));
317 nilfs_copy_page(dpage, page, 0);
318 unlock_page(dpage);
319 put_page(dpage);
320 /* Do we not need to remove page from smap here? */
321 } else {
322 struct page *p;
323
324 /* move the page to the destination cache */
325 xa_lock_irq(&smap->i_pages);
326 p = __xa_erase(&smap->i_pages, offset);
327 WARN_ON(page != p);
328 smap->nrpages--;
329 xa_unlock_irq(&smap->i_pages);
330
331 xa_lock_irq(&dmap->i_pages);
332 p = __xa_store(&dmap->i_pages, offset, page, GFP_NOFS);
333 if (unlikely(p)) {
334 /* Probably -ENOMEM */
335 page->mapping = NULL;
336 put_page(page);
337 } else {
338 page->mapping = dmap;
339 dmap->nrpages++;
340 if (PageDirty(page))
341 __xa_set_mark(&dmap->i_pages, offset,
342 PAGECACHE_TAG_DIRTY);
343 }
344 xa_unlock_irq(&dmap->i_pages);
345 }
346 unlock_page(page);
347 }
348 pagevec_release(&pvec);
349 cond_resched();
350
351 goto repeat;
352 }
353
354 /**
355 * nilfs_clear_dirty_pages - discard dirty pages in address space
356 * @mapping: address space with dirty pages for discarding
357 * @silent: suppress [true] or print [false] warning messages
358 */
nilfs_clear_dirty_pages(struct address_space * mapping,bool silent)359 void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
360 {
361 struct pagevec pvec;
362 unsigned int i;
363 pgoff_t index = 0;
364
365 pagevec_init(&pvec);
366
367 while (pagevec_lookup_tag(&pvec, mapping, &index,
368 PAGECACHE_TAG_DIRTY)) {
369 for (i = 0; i < pagevec_count(&pvec); i++) {
370 struct page *page = pvec.pages[i];
371
372 lock_page(page);
373
374 /*
375 * This page may have been removed from the address
376 * space by truncation or invalidation when the lock
377 * was acquired. Skip processing in that case.
378 */
379 if (likely(page->mapping == mapping))
380 nilfs_clear_dirty_page(page, silent);
381
382 unlock_page(page);
383 }
384 pagevec_release(&pvec);
385 cond_resched();
386 }
387 }
388
389 /**
390 * nilfs_clear_dirty_page - discard dirty page
391 * @page: dirty page that will be discarded
392 * @silent: suppress [true] or print [false] warning messages
393 */
nilfs_clear_dirty_page(struct page * page,bool silent)394 void nilfs_clear_dirty_page(struct page *page, bool silent)
395 {
396 struct inode *inode = page->mapping->host;
397 struct super_block *sb = inode->i_sb;
398
399 BUG_ON(!PageLocked(page));
400
401 if (!silent)
402 nilfs_warn(sb, "discard dirty page: offset=%lld, ino=%lu",
403 page_offset(page), inode->i_ino);
404
405 ClearPageUptodate(page);
406 ClearPageMappedToDisk(page);
407
408 if (page_has_buffers(page)) {
409 struct buffer_head *bh, *head;
410 const unsigned long clear_bits =
411 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
412 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
413 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
414
415 bh = head = page_buffers(page);
416 do {
417 lock_buffer(bh);
418 if (!silent)
419 nilfs_warn(sb,
420 "discard dirty block: blocknr=%llu, size=%zu",
421 (u64)bh->b_blocknr, bh->b_size);
422
423 set_mask_bits(&bh->b_state, clear_bits, 0);
424 unlock_buffer(bh);
425 } while (bh = bh->b_this_page, bh != head);
426 }
427
428 __nilfs_clear_page_dirty(page);
429 }
430
nilfs_page_count_clean_buffers(struct page * page,unsigned int from,unsigned int to)431 unsigned int nilfs_page_count_clean_buffers(struct page *page,
432 unsigned int from, unsigned int to)
433 {
434 unsigned int block_start, block_end;
435 struct buffer_head *bh, *head;
436 unsigned int nc = 0;
437
438 for (bh = head = page_buffers(page), block_start = 0;
439 bh != head || !block_start;
440 block_start = block_end, bh = bh->b_this_page) {
441 block_end = block_start + bh->b_size;
442 if (block_end > from && block_start < to && !buffer_dirty(bh))
443 nc++;
444 }
445 return nc;
446 }
447
nilfs_mapping_init(struct address_space * mapping,struct inode * inode)448 void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
449 {
450 mapping->host = inode;
451 mapping->flags = 0;
452 mapping_set_gfp_mask(mapping, GFP_NOFS);
453 mapping->private_data = NULL;
454 mapping->a_ops = &empty_aops;
455 }
456
457 /*
458 * NILFS2 needs clear_page_dirty() in the following two cases:
459 *
460 * 1) For B-tree node pages and data pages of DAT file, NILFS2 clears dirty
461 * flag of pages when it copies back pages from shadow cache to the
462 * original cache.
463 *
464 * 2) Some B-tree operations like insertion or deletion may dispose buffers
465 * in dirty state, and this needs to cancel the dirty state of their pages.
466 */
__nilfs_clear_page_dirty(struct page * page)467 int __nilfs_clear_page_dirty(struct page *page)
468 {
469 struct address_space *mapping = page->mapping;
470
471 if (mapping) {
472 xa_lock_irq(&mapping->i_pages);
473 if (test_bit(PG_dirty, &page->flags)) {
474 __xa_clear_mark(&mapping->i_pages, page_index(page),
475 PAGECACHE_TAG_DIRTY);
476 xa_unlock_irq(&mapping->i_pages);
477 return clear_page_dirty_for_io(page);
478 }
479 xa_unlock_irq(&mapping->i_pages);
480 return 0;
481 }
482 return TestClearPageDirty(page);
483 }
484
485 /**
486 * nilfs_find_uncommitted_extent - find extent of uncommitted data
487 * @inode: inode
488 * @start_blk: start block offset (in)
489 * @blkoff: start offset of the found extent (out)
490 *
491 * This function searches an extent of buffers marked "delayed" which
492 * starts from a block offset equal to or larger than @start_blk. If
493 * such an extent was found, this will store the start offset in
494 * @blkoff and return its length in blocks. Otherwise, zero is
495 * returned.
496 */
nilfs_find_uncommitted_extent(struct inode * inode,sector_t start_blk,sector_t * blkoff)497 unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
498 sector_t start_blk,
499 sector_t *blkoff)
500 {
501 unsigned int i;
502 pgoff_t index;
503 unsigned int nblocks_in_page;
504 unsigned long length = 0;
505 sector_t b;
506 struct pagevec pvec;
507 struct page *page;
508
509 if (inode->i_mapping->nrpages == 0)
510 return 0;
511
512 index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
513 nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits);
514
515 pagevec_init(&pvec);
516
517 repeat:
518 pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
519 pvec.pages);
520 if (pvec.nr == 0)
521 return length;
522
523 if (length > 0 && pvec.pages[0]->index > index)
524 goto out;
525
526 b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits);
527 i = 0;
528 do {
529 page = pvec.pages[i];
530
531 lock_page(page);
532 if (page_has_buffers(page)) {
533 struct buffer_head *bh, *head;
534
535 bh = head = page_buffers(page);
536 do {
537 if (b < start_blk)
538 continue;
539 if (buffer_delay(bh)) {
540 if (length == 0)
541 *blkoff = b;
542 length++;
543 } else if (length > 0) {
544 goto out_locked;
545 }
546 } while (++b, bh = bh->b_this_page, bh != head);
547 } else {
548 if (length > 0)
549 goto out_locked;
550
551 b += nblocks_in_page;
552 }
553 unlock_page(page);
554
555 } while (++i < pagevec_count(&pvec));
556
557 index = page->index + 1;
558 pagevec_release(&pvec);
559 cond_resched();
560 goto repeat;
561
562 out_locked:
563 unlock_page(page);
564 out:
565 pagevec_release(&pvec);
566 return length;
567 }
568