1 // SPDX-License-Identifier: GPL-2.0+
3 * page.c - buffer/page management specific to NILFS
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
7 * Written by Ryusuke Konishi and Seiji Kihara.
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>
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))
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)
33 unsigned long first_block;
34 struct buffer_head *bh;
36 if (!page_has_buffers(page))
37 create_empty_buffers(page, 1 << blkbits, b_state);
39 first_block = (unsigned long)index << (PAGE_SHIFT - blkbits);
40 bh = nilfs_page_get_nth_block(page, block - first_block);
47 struct buffer_head *nilfs_grab_buffer(struct inode *inode,
48 struct address_space *mapping,
50 unsigned long b_state)
52 int blkbits = inode->i_blkbits;
53 pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits);
55 struct buffer_head *bh;
57 page = grab_cache_page(mapping, index);
61 bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
71 * nilfs_forget_buffer - discard dirty state
72 * @inode: owner inode of the buffer
73 * @bh: buffer head of the buffer to be discarded
75 void nilfs_forget_buffer(struct buffer_head *bh)
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));
84 set_mask_bits(&bh->b_state, clear_bits, 0);
85 if (nilfs_page_buffers_clean(page))
86 __nilfs_clear_page_dirty(page);
89 ClearPageUptodate(page);
90 ClearPageMappedToDisk(page);
96 * nilfs_copy_buffer -- copy buffer data and flags
97 * @dbh: destination buffer
100 void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
102 void *kaddr0, *kaddr1;
104 struct page *spage = sbh->b_page, *dpage = dbh->b_page;
105 struct buffer_head *bh;
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);
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;
118 bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped));
119 while ((bh = bh->b_this_page) != dbh) {
124 if (bits & BIT(BH_Uptodate))
125 SetPageUptodate(dpage);
127 ClearPageUptodate(dpage);
128 if (bits & BIT(BH_Mapped))
129 SetPageMappedToDisk(dpage);
131 ClearPageMappedToDisk(dpage);
135 * nilfs_page_buffers_clean - check if a page has dirty buffers or not.
136 * @page: page to be checked
138 * nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
139 * Otherwise, it returns non-zero value.
141 int nilfs_page_buffers_clean(struct page *page)
143 struct buffer_head *bh, *head;
145 bh = head = page_buffers(page);
147 if (buffer_dirty(bh))
149 bh = bh->b_this_page;
150 } while (bh != head);
154 void nilfs_page_bug(struct page *page)
156 struct address_space *m;
159 if (unlikely(!page)) {
160 printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
165 ino = m ? m->host->i_ino : 0;
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);
172 if (page_has_buffers(page)) {
173 struct buffer_head *bh, *head;
176 bh = head = page_buffers(page);
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);
188 * nilfs_copy_page -- copy the page with buffers
189 * @dst: destination page
191 * @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
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
197 static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
199 struct buffer_head *dbh, *dbufs, *sbh, *sbufs;
200 unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
202 BUG_ON(PageWriteback(dst));
204 sbh = sbufs = page_buffers(src);
205 if (!page_has_buffers(dst))
206 create_empty_buffers(dst, sbh->b_size, 0);
209 mask |= BIT(BH_Dirty);
211 dbh = dbufs = page_buffers(dst);
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);
222 copy_highpage(dst, src);
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);
236 sbh = sbh->b_this_page;
237 dbh = dbh->b_this_page;
238 } while (dbh != dbufs);
241 int nilfs_copy_dirty_pages(struct address_space *dmap,
242 struct address_space *smap)
251 if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY))
254 for (i = 0; i < pagevec_count(&pvec); i++) {
255 struct page *page = pvec.pages[i], *dpage;
258 if (unlikely(!PageDirty(page)))
259 NILFS_PAGE_BUG(page, "inconsistent dirty state");
261 dpage = grab_cache_page(dmap, page->index);
262 if (unlikely(!dpage)) {
263 /* No empty page is added to the page cache */
268 if (unlikely(!page_has_buffers(page)))
270 "found empty page in dat page cache");
272 nilfs_copy_page(dpage, page, 1);
273 __set_page_dirty_nobuffers(dpage);
279 pagevec_release(&pvec);
288 * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
289 * @dmap: destination page cache
290 * @smap: source page cache
292 * No pages must be added to the cache during this process.
293 * This must be ensured by the caller.
295 void nilfs_copy_back_pages(struct address_space *dmap,
296 struct address_space *smap)
304 n = pagevec_lookup(&pvec, smap, &index);
308 for (i = 0; i < pagevec_count(&pvec); i++) {
309 struct page *page = pvec.pages[i], *dpage;
310 pgoff_t offset = page->index;
313 dpage = find_lock_page(dmap, offset);
315 /* overwrite existing page in the destination cache */
316 WARN_ON(PageDirty(dpage));
317 nilfs_copy_page(dpage, page, 0);
320 /* Do we not need to remove page from smap here? */
324 /* move the page to the destination cache */
325 xa_lock_irq(&smap->i_pages);
326 p = __xa_erase(&smap->i_pages, offset);
329 xa_unlock_irq(&smap->i_pages);
331 xa_lock_irq(&dmap->i_pages);
332 p = __xa_store(&dmap->i_pages, offset, page, GFP_NOFS);
334 /* Probably -ENOMEM */
335 page->mapping = NULL;
338 page->mapping = dmap;
341 __xa_set_mark(&dmap->i_pages, offset,
342 PAGECACHE_TAG_DIRTY);
344 xa_unlock_irq(&dmap->i_pages);
348 pagevec_release(&pvec);
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
359 void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
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];
373 nilfs_clear_dirty_page(page, silent);
376 pagevec_release(&pvec);
382 * nilfs_clear_dirty_page - discard dirty page
383 * @page: dirty page that will be discarded
384 * @silent: suppress [true] or print [false] warning messages
386 void nilfs_clear_dirty_page(struct page *page, bool silent)
388 struct inode *inode = page->mapping->host;
389 struct super_block *sb = inode->i_sb;
391 BUG_ON(!PageLocked(page));
394 nilfs_msg(sb, KERN_WARNING,
395 "discard dirty page: offset=%lld, ino=%lu",
396 page_offset(page), inode->i_ino);
398 ClearPageUptodate(page);
399 ClearPageMappedToDisk(page);
401 if (page_has_buffers(page)) {
402 struct buffer_head *bh, *head;
403 const unsigned long clear_bits =
404 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
405 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
406 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
408 bh = head = page_buffers(page);
412 nilfs_msg(sb, KERN_WARNING,
413 "discard dirty block: blocknr=%llu, size=%zu",
414 (u64)bh->b_blocknr, bh->b_size);
416 set_mask_bits(&bh->b_state, clear_bits, 0);
418 } while (bh = bh->b_this_page, bh != head);
421 __nilfs_clear_page_dirty(page);
424 unsigned int nilfs_page_count_clean_buffers(struct page *page,
425 unsigned int from, unsigned int to)
427 unsigned int block_start, block_end;
428 struct buffer_head *bh, *head;
431 for (bh = head = page_buffers(page), block_start = 0;
432 bh != head || !block_start;
433 block_start = block_end, bh = bh->b_this_page) {
434 block_end = block_start + bh->b_size;
435 if (block_end > from && block_start < to && !buffer_dirty(bh))
441 void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
443 mapping->host = inode;
445 mapping_set_gfp_mask(mapping, GFP_NOFS);
446 mapping->private_data = NULL;
447 mapping->a_ops = &empty_aops;
451 * NILFS2 needs clear_page_dirty() in the following two cases:
453 * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
454 * page dirty flags when it copies back pages from the shadow cache
455 * (gcdat->{i_mapping,i_btnode_cache}) to its original cache
456 * (dat->{i_mapping,i_btnode_cache}).
458 * 2) Some B-tree operations like insertion or deletion may dispose buffers
459 * in dirty state, and this needs to cancel the dirty state of their pages.
461 int __nilfs_clear_page_dirty(struct page *page)
463 struct address_space *mapping = page->mapping;
466 xa_lock_irq(&mapping->i_pages);
467 if (test_bit(PG_dirty, &page->flags)) {
468 __xa_clear_mark(&mapping->i_pages, page_index(page),
469 PAGECACHE_TAG_DIRTY);
470 xa_unlock_irq(&mapping->i_pages);
471 return clear_page_dirty_for_io(page);
473 xa_unlock_irq(&mapping->i_pages);
476 return TestClearPageDirty(page);
480 * nilfs_find_uncommitted_extent - find extent of uncommitted data
482 * @start_blk: start block offset (in)
483 * @blkoff: start offset of the found extent (out)
485 * This function searches an extent of buffers marked "delayed" which
486 * starts from a block offset equal to or larger than @start_blk. If
487 * such an extent was found, this will store the start offset in
488 * @blkoff and return its length in blocks. Otherwise, zero is
491 unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
497 unsigned int nblocks_in_page;
498 unsigned long length = 0;
503 if (inode->i_mapping->nrpages == 0)
506 index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
507 nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits);
512 pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
517 if (length > 0 && pvec.pages[0]->index > index)
520 b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits);
523 page = pvec.pages[i];
526 if (page_has_buffers(page)) {
527 struct buffer_head *bh, *head;
529 bh = head = page_buffers(page);
533 if (buffer_delay(bh)) {
537 } else if (length > 0) {
540 } while (++b, bh = bh->b_this_page, bh != head);
545 b += nblocks_in_page;
549 } while (++i < pagevec_count(&pvec));
551 index = page->index + 1;
552 pagevec_release(&pvec);
559 pagevec_release(&pvec);