2 * page.c - buffer/page management specific to NILFS
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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.
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.
16 * Written by Ryusuke Konishi and Seiji Kihara.
19 #include <linux/pagemap.h>
20 #include <linux/writeback.h>
21 #include <linux/swap.h>
22 #include <linux/bitops.h>
23 #include <linux/page-flags.h>
24 #include <linux/list.h>
25 #include <linux/highmem.h>
26 #include <linux/pagevec.h>
27 #include <linux/gfp.h>
33 #define NILFS_BUFFER_INHERENT_BITS \
34 (BIT(BH_Uptodate) | BIT(BH_Mapped) | BIT(BH_NILFS_Node) | \
35 BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Checked))
37 static struct buffer_head *
38 __nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
39 int blkbits, unsigned long b_state)
42 unsigned long first_block;
43 struct buffer_head *bh;
45 if (!page_has_buffers(page))
46 create_empty_buffers(page, 1 << blkbits, b_state);
48 first_block = (unsigned long)index << (PAGE_SHIFT - blkbits);
49 bh = nilfs_page_get_nth_block(page, block - first_block);
56 struct buffer_head *nilfs_grab_buffer(struct inode *inode,
57 struct address_space *mapping,
59 unsigned long b_state)
61 int blkbits = inode->i_blkbits;
62 pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits);
64 struct buffer_head *bh;
66 page = grab_cache_page(mapping, index);
70 bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
80 * nilfs_forget_buffer - discard dirty state
81 * @inode: owner inode of the buffer
82 * @bh: buffer head of the buffer to be discarded
84 void nilfs_forget_buffer(struct buffer_head *bh)
86 struct page *page = bh->b_page;
87 const unsigned long clear_bits =
88 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
89 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
90 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
93 set_mask_bits(&bh->b_state, clear_bits, 0);
94 if (nilfs_page_buffers_clean(page))
95 __nilfs_clear_page_dirty(page);
98 ClearPageUptodate(page);
99 ClearPageMappedToDisk(page);
105 * nilfs_copy_buffer -- copy buffer data and flags
106 * @dbh: destination buffer
107 * @sbh: source buffer
109 void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
111 void *kaddr0, *kaddr1;
113 struct page *spage = sbh->b_page, *dpage = dbh->b_page;
114 struct buffer_head *bh;
116 kaddr0 = kmap_atomic(spage);
117 kaddr1 = kmap_atomic(dpage);
118 memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
119 kunmap_atomic(kaddr1);
120 kunmap_atomic(kaddr0);
122 dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
123 dbh->b_blocknr = sbh->b_blocknr;
124 dbh->b_bdev = sbh->b_bdev;
127 bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped));
128 while ((bh = bh->b_this_page) != dbh) {
133 if (bits & BIT(BH_Uptodate))
134 SetPageUptodate(dpage);
136 ClearPageUptodate(dpage);
137 if (bits & BIT(BH_Mapped))
138 SetPageMappedToDisk(dpage);
140 ClearPageMappedToDisk(dpage);
144 * nilfs_page_buffers_clean - check if a page has dirty buffers or not.
145 * @page: page to be checked
147 * nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
148 * Otherwise, it returns non-zero value.
150 int nilfs_page_buffers_clean(struct page *page)
152 struct buffer_head *bh, *head;
154 bh = head = page_buffers(page);
156 if (buffer_dirty(bh))
158 bh = bh->b_this_page;
159 } while (bh != head);
163 void nilfs_page_bug(struct page *page)
165 struct address_space *m;
168 if (unlikely(!page)) {
169 printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
174 ino = m ? m->host->i_ino : 0;
176 printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
177 "mapping=%p ino=%lu\n",
178 page, page_ref_count(page),
179 (unsigned long long)page->index, page->flags, m, ino);
181 if (page_has_buffers(page)) {
182 struct buffer_head *bh, *head;
185 bh = head = page_buffers(page);
188 " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
189 i++, bh, atomic_read(&bh->b_count),
190 (unsigned long long)bh->b_blocknr, bh->b_state);
191 bh = bh->b_this_page;
192 } while (bh != head);
197 * nilfs_copy_page -- copy the page with buffers
198 * @dst: destination page
200 * @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
202 * This function is for both data pages and btnode pages. The dirty flag
203 * should be treated by caller. The page must not be under i/o.
204 * Both src and dst page must be locked
206 static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
208 struct buffer_head *dbh, *dbufs, *sbh, *sbufs;
209 unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
211 BUG_ON(PageWriteback(dst));
213 sbh = sbufs = page_buffers(src);
214 if (!page_has_buffers(dst))
215 create_empty_buffers(dst, sbh->b_size, 0);
218 mask |= BIT(BH_Dirty);
220 dbh = dbufs = page_buffers(dst);
224 dbh->b_state = sbh->b_state & mask;
225 dbh->b_blocknr = sbh->b_blocknr;
226 dbh->b_bdev = sbh->b_bdev;
227 sbh = sbh->b_this_page;
228 dbh = dbh->b_this_page;
229 } while (dbh != dbufs);
231 copy_highpage(dst, src);
233 if (PageUptodate(src) && !PageUptodate(dst))
234 SetPageUptodate(dst);
235 else if (!PageUptodate(src) && PageUptodate(dst))
236 ClearPageUptodate(dst);
237 if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
238 SetPageMappedToDisk(dst);
239 else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
240 ClearPageMappedToDisk(dst);
245 sbh = sbh->b_this_page;
246 dbh = dbh->b_this_page;
247 } while (dbh != dbufs);
250 int nilfs_copy_dirty_pages(struct address_space *dmap,
251 struct address_space *smap)
260 if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY))
263 for (i = 0; i < pagevec_count(&pvec); i++) {
264 struct page *page = pvec.pages[i], *dpage;
267 if (unlikely(!PageDirty(page)))
268 NILFS_PAGE_BUG(page, "inconsistent dirty state");
270 dpage = grab_cache_page(dmap, page->index);
271 if (unlikely(!dpage)) {
272 /* No empty page is added to the page cache */
277 if (unlikely(!page_has_buffers(page)))
279 "found empty page in dat page cache");
281 nilfs_copy_page(dpage, page, 1);
282 __set_page_dirty_nobuffers(dpage);
288 pagevec_release(&pvec);
297 * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
298 * @dmap: destination page cache
299 * @smap: source page cache
301 * No pages must no be added to the cache during this process.
302 * This must be ensured by the caller.
304 void nilfs_copy_back_pages(struct address_space *dmap,
305 struct address_space *smap)
314 n = pagevec_lookup(&pvec, smap, &index);
318 for (i = 0; i < pagevec_count(&pvec); i++) {
319 struct page *page = pvec.pages[i], *dpage;
320 pgoff_t offset = page->index;
323 dpage = find_lock_page(dmap, offset);
325 /* override existing page on the destination cache */
326 WARN_ON(PageDirty(dpage));
327 nilfs_copy_page(dpage, page, 0);
333 /* move the page to the destination cache */
334 spin_lock_irq(&smap->tree_lock);
335 page2 = radix_tree_delete(&smap->page_tree, offset);
336 WARN_ON(page2 != page);
339 spin_unlock_irq(&smap->tree_lock);
341 spin_lock_irq(&dmap->tree_lock);
342 err = radix_tree_insert(&dmap->page_tree, offset, page);
343 if (unlikely(err < 0)) {
344 WARN_ON(err == -EEXIST);
345 page->mapping = NULL;
346 put_page(page); /* for cache */
348 page->mapping = dmap;
351 radix_tree_tag_set(&dmap->page_tree,
353 PAGECACHE_TAG_DIRTY);
355 spin_unlock_irq(&dmap->tree_lock);
359 pagevec_release(&pvec);
366 * nilfs_clear_dirty_pages - discard dirty pages in address space
367 * @mapping: address space with dirty pages for discarding
368 * @silent: suppress [true] or print [false] warning messages
370 void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
378 while (pagevec_lookup_tag(&pvec, mapping, &index,
379 PAGECACHE_TAG_DIRTY)) {
380 for (i = 0; i < pagevec_count(&pvec); i++) {
381 struct page *page = pvec.pages[i];
384 nilfs_clear_dirty_page(page, silent);
387 pagevec_release(&pvec);
393 * nilfs_clear_dirty_page - discard dirty page
394 * @page: dirty page that will be discarded
395 * @silent: suppress [true] or print [false] warning messages
397 void nilfs_clear_dirty_page(struct page *page, bool silent)
399 struct inode *inode = page->mapping->host;
400 struct super_block *sb = inode->i_sb;
402 BUG_ON(!PageLocked(page));
405 nilfs_msg(sb, KERN_WARNING,
406 "discard dirty page: offset=%lld, ino=%lu",
407 page_offset(page), inode->i_ino);
409 ClearPageUptodate(page);
410 ClearPageMappedToDisk(page);
412 if (page_has_buffers(page)) {
413 struct buffer_head *bh, *head;
414 const unsigned long clear_bits =
415 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
416 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
417 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
419 bh = head = page_buffers(page);
423 nilfs_msg(sb, KERN_WARNING,
424 "discard dirty block: blocknr=%llu, size=%zu",
425 (u64)bh->b_blocknr, bh->b_size);
427 set_mask_bits(&bh->b_state, clear_bits, 0);
429 } while (bh = bh->b_this_page, bh != head);
432 __nilfs_clear_page_dirty(page);
435 unsigned int nilfs_page_count_clean_buffers(struct page *page,
436 unsigned int from, unsigned int to)
438 unsigned int block_start, block_end;
439 struct buffer_head *bh, *head;
442 for (bh = head = page_buffers(page), block_start = 0;
443 bh != head || !block_start;
444 block_start = block_end, bh = bh->b_this_page) {
445 block_end = block_start + bh->b_size;
446 if (block_end > from && block_start < to && !buffer_dirty(bh))
452 void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
454 mapping->host = inode;
456 mapping_set_gfp_mask(mapping, GFP_NOFS);
457 mapping->private_data = NULL;
458 mapping->a_ops = &empty_aops;
462 * NILFS2 needs clear_page_dirty() in the following two cases:
464 * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
465 * page dirty flags when it copies back pages from the shadow cache
466 * (gcdat->{i_mapping,i_btnode_cache}) to its original cache
467 * (dat->{i_mapping,i_btnode_cache}).
469 * 2) Some B-tree operations like insertion or deletion may dispose buffers
470 * in dirty state, and this needs to cancel the dirty state of their pages.
472 int __nilfs_clear_page_dirty(struct page *page)
474 struct address_space *mapping = page->mapping;
477 spin_lock_irq(&mapping->tree_lock);
478 if (test_bit(PG_dirty, &page->flags)) {
479 radix_tree_tag_clear(&mapping->page_tree,
481 PAGECACHE_TAG_DIRTY);
482 spin_unlock_irq(&mapping->tree_lock);
483 return clear_page_dirty_for_io(page);
485 spin_unlock_irq(&mapping->tree_lock);
488 return TestClearPageDirty(page);
492 * nilfs_find_uncommitted_extent - find extent of uncommitted data
494 * @start_blk: start block offset (in)
495 * @blkoff: start offset of the found extent (out)
497 * This function searches an extent of buffers marked "delayed" which
498 * starts from a block offset equal to or larger than @start_blk. If
499 * such an extent was found, this will store the start offset in
500 * @blkoff and return its length in blocks. Otherwise, zero is
503 unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
509 unsigned int nblocks_in_page;
510 unsigned long length = 0;
515 if (inode->i_mapping->nrpages == 0)
518 index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
519 nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits);
524 pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
529 if (length > 0 && pvec.pages[0]->index > index)
532 b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits);
535 page = pvec.pages[i];
538 if (page_has_buffers(page)) {
539 struct buffer_head *bh, *head;
541 bh = head = page_buffers(page);
545 if (buffer_delay(bh)) {
549 } else if (length > 0) {
552 } while (++b, bh = bh->b_this_page, bh != head);
557 b += nblocks_in_page;
561 } while (++i < pagevec_count(&pvec));
563 index = page->index + 1;
564 pagevec_release(&pvec);
571 pagevec_release(&pvec);