GNU Linux-libre 5.19-rc6-gnu
[releases.git] / fs / nilfs2 / page.c
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
28 static 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
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  * @bh: buffer head of the buffer to be discarded
73  */
74 void 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  */
99 void 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  */
140 int 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
153 void 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  */
196 static 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
240 int 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);
249 repeat:
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  */
294 void nilfs_copy_back_pages(struct address_space *dmap,
295                            struct address_space *smap)
296 {
297         struct pagevec pvec;
298         unsigned int i, n;
299         pgoff_t index = 0;
300
301         pagevec_init(&pvec);
302 repeat:
303         n = pagevec_lookup(&pvec, smap, &index);
304         if (!n)
305                 return;
306
307         for (i = 0; i < pagevec_count(&pvec); i++) {
308                 struct page *page = pvec.pages[i], *dpage;
309                 pgoff_t offset = page->index;
310
311                 lock_page(page);
312                 dpage = find_lock_page(dmap, offset);
313                 if (dpage) {
314                         /* overwrite existing page in the destination cache */
315                         WARN_ON(PageDirty(dpage));
316                         nilfs_copy_page(dpage, page, 0);
317                         unlock_page(dpage);
318                         put_page(dpage);
319                         /* Do we not need to remove page from smap here? */
320                 } else {
321                         struct page *p;
322
323                         /* move the page to the destination cache */
324                         xa_lock_irq(&smap->i_pages);
325                         p = __xa_erase(&smap->i_pages, offset);
326                         WARN_ON(page != p);
327                         smap->nrpages--;
328                         xa_unlock_irq(&smap->i_pages);
329
330                         xa_lock_irq(&dmap->i_pages);
331                         p = __xa_store(&dmap->i_pages, offset, page, GFP_NOFS);
332                         if (unlikely(p)) {
333                                 /* Probably -ENOMEM */
334                                 page->mapping = NULL;
335                                 put_page(page);
336                         } else {
337                                 page->mapping = dmap;
338                                 dmap->nrpages++;
339                                 if (PageDirty(page))
340                                         __xa_set_mark(&dmap->i_pages, offset,
341                                                         PAGECACHE_TAG_DIRTY);
342                         }
343                         xa_unlock_irq(&dmap->i_pages);
344                 }
345                 unlock_page(page);
346         }
347         pagevec_release(&pvec);
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  */
358 void 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  */
385 void 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
422 unsigned 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  */
449 int __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  */
479 unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
480                                             sector_t start_blk,
481                                             sector_t *blkoff)
482 {
483         unsigned int i;
484         pgoff_t index;
485         unsigned int nblocks_in_page;
486         unsigned long length = 0;
487         sector_t b;
488         struct pagevec pvec;
489         struct page *page;
490
491         if (inode->i_mapping->nrpages == 0)
492                 return 0;
493
494         index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
495         nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits);
496
497         pagevec_init(&pvec);
498
499 repeat:
500         pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
501                                         pvec.pages);
502         if (pvec.nr == 0)
503                 return length;
504
505         if (length > 0 && pvec.pages[0]->index > index)
506                 goto out;
507
508         b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits);
509         i = 0;
510         do {
511                 page = pvec.pages[i];
512
513                 lock_page(page);
514                 if (page_has_buffers(page)) {
515                         struct buffer_head *bh, *head;
516
517                         bh = head = page_buffers(page);
518                         do {
519                                 if (b < start_blk)
520                                         continue;
521                                 if (buffer_delay(bh)) {
522                                         if (length == 0)
523                                                 *blkoff = b;
524                                         length++;
525                                 } else if (length > 0) {
526                                         goto out_locked;
527                                 }
528                         } while (++b, bh = bh->b_this_page, bh != head);
529                 } else {
530                         if (length > 0)
531                                 goto out_locked;
532
533                         b += nblocks_in_page;
534                 }
535                 unlock_page(page);
536
537         } while (++i < pagevec_count(&pvec));
538
539         index = page->index + 1;
540         pagevec_release(&pvec);
541         cond_resched();
542         goto repeat;
543
544 out_locked:
545         unlock_page(page);
546 out:
547         pagevec_release(&pvec);
548         return length;
549 }