diff options
Diffstat (limited to 'fs/nilfs2/page.c')
-rw-r--r-- | fs/nilfs2/page.c | 549 |
1 files changed, 549 insertions, 0 deletions
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c new file mode 100644 index 0000000000..b4e54d079b --- /dev/null +++ b/fs/nilfs2/page.c @@ -0,0 +1,549 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Buffer/page management specific to NILFS + * + * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. + * + * Written by Ryusuke Konishi and Seiji Kihara. + */ + +#include <linux/pagemap.h> +#include <linux/writeback.h> +#include <linux/swap.h> +#include <linux/bitops.h> +#include <linux/page-flags.h> +#include <linux/list.h> +#include <linux/highmem.h> +#include <linux/pagevec.h> +#include <linux/gfp.h> +#include "nilfs.h" +#include "page.h" +#include "mdt.h" + + +#define NILFS_BUFFER_INHERENT_BITS \ + (BIT(BH_Uptodate) | BIT(BH_Mapped) | BIT(BH_NILFS_Node) | \ + BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Checked)) + +static struct buffer_head * +__nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index, + int blkbits, unsigned long b_state) + +{ + unsigned long first_block; + struct buffer_head *bh; + + if (!page_has_buffers(page)) + create_empty_buffers(page, 1 << blkbits, b_state); + + first_block = (unsigned long)index << (PAGE_SHIFT - blkbits); + bh = nilfs_page_get_nth_block(page, block - first_block); + + touch_buffer(bh); + wait_on_buffer(bh); + return bh; +} + +struct buffer_head *nilfs_grab_buffer(struct inode *inode, + struct address_space *mapping, + unsigned long blkoff, + unsigned long b_state) +{ + int blkbits = inode->i_blkbits; + pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits); + struct page *page; + struct buffer_head *bh; + + page = grab_cache_page(mapping, index); + if (unlikely(!page)) + return NULL; + + bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state); + if (unlikely(!bh)) { + unlock_page(page); + put_page(page); + return NULL; + } + return bh; +} + +/** + * nilfs_forget_buffer - discard dirty state + * @bh: buffer head of the buffer to be discarded + */ +void nilfs_forget_buffer(struct buffer_head *bh) +{ + struct page *page = bh->b_page; + const unsigned long clear_bits = + (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) | + BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) | + BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected)); + + lock_buffer(bh); + set_mask_bits(&bh->b_state, clear_bits, 0); + if (nilfs_page_buffers_clean(page)) + __nilfs_clear_page_dirty(page); + + bh->b_blocknr = -1; + ClearPageUptodate(page); + ClearPageMappedToDisk(page); + unlock_buffer(bh); + brelse(bh); +} + +/** + * nilfs_copy_buffer -- copy buffer data and flags + * @dbh: destination buffer + * @sbh: source buffer + */ +void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh) +{ + void *kaddr0, *kaddr1; + unsigned long bits; + struct page *spage = sbh->b_page, *dpage = dbh->b_page; + struct buffer_head *bh; + + kaddr0 = kmap_atomic(spage); + kaddr1 = kmap_atomic(dpage); + memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size); + kunmap_atomic(kaddr1); + kunmap_atomic(kaddr0); + + dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS; + dbh->b_blocknr = sbh->b_blocknr; + dbh->b_bdev = sbh->b_bdev; + + bh = dbh; + bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped)); + while ((bh = bh->b_this_page) != dbh) { + lock_buffer(bh); + bits &= bh->b_state; + unlock_buffer(bh); + } + if (bits & BIT(BH_Uptodate)) + SetPageUptodate(dpage); + else + ClearPageUptodate(dpage); + if (bits & BIT(BH_Mapped)) + SetPageMappedToDisk(dpage); + else + ClearPageMappedToDisk(dpage); +} + +/** + * nilfs_page_buffers_clean - check if a page has dirty buffers or not. + * @page: page to be checked + * + * nilfs_page_buffers_clean() returns zero if the page has dirty buffers. + * Otherwise, it returns non-zero value. + */ +int nilfs_page_buffers_clean(struct page *page) +{ + struct buffer_head *bh, *head; + + bh = head = page_buffers(page); + do { + if (buffer_dirty(bh)) + return 0; + bh = bh->b_this_page; + } while (bh != head); + return 1; +} + +void nilfs_page_bug(struct page *page) +{ + struct address_space *m; + unsigned long ino; + + if (unlikely(!page)) { + printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n"); + return; + } + + m = page->mapping; + ino = m ? m->host->i_ino : 0; + + printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx " + "mapping=%p ino=%lu\n", + page, page_ref_count(page), + (unsigned long long)page->index, page->flags, m, ino); + + if (page_has_buffers(page)) { + struct buffer_head *bh, *head; + int i = 0; + + bh = head = page_buffers(page); + do { + printk(KERN_CRIT + " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n", + i++, bh, atomic_read(&bh->b_count), + (unsigned long long)bh->b_blocknr, bh->b_state); + bh = bh->b_this_page; + } while (bh != head); + } +} + +/** + * nilfs_copy_page -- copy the page with buffers + * @dst: destination page + * @src: source page + * @copy_dirty: flag whether to copy dirty states on the page's buffer heads. + * + * This function is for both data pages and btnode pages. The dirty flag + * should be treated by caller. The page must not be under i/o. + * Both src and dst page must be locked + */ +static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty) +{ + struct buffer_head *dbh, *dbufs, *sbh; + unsigned long mask = NILFS_BUFFER_INHERENT_BITS; + + BUG_ON(PageWriteback(dst)); + + sbh = page_buffers(src); + if (!page_has_buffers(dst)) + create_empty_buffers(dst, sbh->b_size, 0); + + if (copy_dirty) + mask |= BIT(BH_Dirty); + + dbh = dbufs = page_buffers(dst); + do { + lock_buffer(sbh); + lock_buffer(dbh); + dbh->b_state = sbh->b_state & mask; + dbh->b_blocknr = sbh->b_blocknr; + dbh->b_bdev = sbh->b_bdev; + sbh = sbh->b_this_page; + dbh = dbh->b_this_page; + } while (dbh != dbufs); + + copy_highpage(dst, src); + + if (PageUptodate(src) && !PageUptodate(dst)) + SetPageUptodate(dst); + else if (!PageUptodate(src) && PageUptodate(dst)) + ClearPageUptodate(dst); + if (PageMappedToDisk(src) && !PageMappedToDisk(dst)) + SetPageMappedToDisk(dst); + else if (!PageMappedToDisk(src) && PageMappedToDisk(dst)) + ClearPageMappedToDisk(dst); + + do { + unlock_buffer(sbh); + unlock_buffer(dbh); + sbh = sbh->b_this_page; + dbh = dbh->b_this_page; + } while (dbh != dbufs); +} + +int nilfs_copy_dirty_pages(struct address_space *dmap, + struct address_space *smap) +{ + struct folio_batch fbatch; + unsigned int i; + pgoff_t index = 0; + int err = 0; + + folio_batch_init(&fbatch); +repeat: + if (!filemap_get_folios_tag(smap, &index, (pgoff_t)-1, + PAGECACHE_TAG_DIRTY, &fbatch)) + return 0; + + for (i = 0; i < folio_batch_count(&fbatch); i++) { + struct folio *folio = fbatch.folios[i], *dfolio; + + folio_lock(folio); + if (unlikely(!folio_test_dirty(folio))) + NILFS_PAGE_BUG(&folio->page, "inconsistent dirty state"); + + dfolio = filemap_grab_folio(dmap, folio->index); + if (unlikely(IS_ERR(dfolio))) { + /* No empty page is added to the page cache */ + folio_unlock(folio); + err = PTR_ERR(dfolio); + break; + } + if (unlikely(!folio_buffers(folio))) + NILFS_PAGE_BUG(&folio->page, + "found empty page in dat page cache"); + + nilfs_copy_page(&dfolio->page, &folio->page, 1); + filemap_dirty_folio(folio_mapping(dfolio), dfolio); + + folio_unlock(dfolio); + folio_put(dfolio); + folio_unlock(folio); + } + folio_batch_release(&fbatch); + cond_resched(); + + if (likely(!err)) + goto repeat; + return err; +} + +/** + * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache + * @dmap: destination page cache + * @smap: source page cache + * + * No pages must be added to the cache during this process. + * This must be ensured by the caller. + */ +void nilfs_copy_back_pages(struct address_space *dmap, + struct address_space *smap) +{ + struct folio_batch fbatch; + unsigned int i, n; + pgoff_t start = 0; + + folio_batch_init(&fbatch); +repeat: + n = filemap_get_folios(smap, &start, ~0UL, &fbatch); + if (!n) + return; + + for (i = 0; i < folio_batch_count(&fbatch); i++) { + struct folio *folio = fbatch.folios[i], *dfolio; + pgoff_t index = folio->index; + + folio_lock(folio); + dfolio = filemap_lock_folio(dmap, index); + if (!IS_ERR(dfolio)) { + /* overwrite existing folio in the destination cache */ + WARN_ON(folio_test_dirty(dfolio)); + nilfs_copy_page(&dfolio->page, &folio->page, 0); + folio_unlock(dfolio); + folio_put(dfolio); + /* Do we not need to remove folio from smap here? */ + } else { + struct folio *f; + + /* move the folio to the destination cache */ + xa_lock_irq(&smap->i_pages); + f = __xa_erase(&smap->i_pages, index); + WARN_ON(folio != f); + smap->nrpages--; + xa_unlock_irq(&smap->i_pages); + + xa_lock_irq(&dmap->i_pages); + f = __xa_store(&dmap->i_pages, index, folio, GFP_NOFS); + if (unlikely(f)) { + /* Probably -ENOMEM */ + folio->mapping = NULL; + folio_put(folio); + } else { + folio->mapping = dmap; + dmap->nrpages++; + if (folio_test_dirty(folio)) + __xa_set_mark(&dmap->i_pages, index, + PAGECACHE_TAG_DIRTY); + } + xa_unlock_irq(&dmap->i_pages); + } + folio_unlock(folio); + } + folio_batch_release(&fbatch); + cond_resched(); + + goto repeat; +} + +/** + * nilfs_clear_dirty_pages - discard dirty pages in address space + * @mapping: address space with dirty pages for discarding + * @silent: suppress [true] or print [false] warning messages + */ +void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent) +{ + struct folio_batch fbatch; + unsigned int i; + pgoff_t index = 0; + + folio_batch_init(&fbatch); + + while (filemap_get_folios_tag(mapping, &index, (pgoff_t)-1, + PAGECACHE_TAG_DIRTY, &fbatch)) { + for (i = 0; i < folio_batch_count(&fbatch); i++) { + struct folio *folio = fbatch.folios[i]; + + folio_lock(folio); + + /* + * This folio may have been removed from the address + * space by truncation or invalidation when the lock + * was acquired. Skip processing in that case. + */ + if (likely(folio->mapping == mapping)) + nilfs_clear_dirty_page(&folio->page, silent); + + folio_unlock(folio); + } + folio_batch_release(&fbatch); + cond_resched(); + } +} + +/** + * nilfs_clear_dirty_page - discard dirty page + * @page: dirty page that will be discarded + * @silent: suppress [true] or print [false] warning messages + */ +void nilfs_clear_dirty_page(struct page *page, bool silent) +{ + struct inode *inode = page->mapping->host; + struct super_block *sb = inode->i_sb; + + BUG_ON(!PageLocked(page)); + + if (!silent) + nilfs_warn(sb, "discard dirty page: offset=%lld, ino=%lu", + page_offset(page), inode->i_ino); + + ClearPageUptodate(page); + ClearPageMappedToDisk(page); + + if (page_has_buffers(page)) { + struct buffer_head *bh, *head; + const unsigned long clear_bits = + (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) | + BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) | + BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected)); + + bh = head = page_buffers(page); + do { + lock_buffer(bh); + if (!silent) + nilfs_warn(sb, + "discard dirty block: blocknr=%llu, size=%zu", + (u64)bh->b_blocknr, bh->b_size); + + set_mask_bits(&bh->b_state, clear_bits, 0); + unlock_buffer(bh); + } while (bh = bh->b_this_page, bh != head); + } + + __nilfs_clear_page_dirty(page); +} + +unsigned int nilfs_page_count_clean_buffers(struct page *page, + unsigned int from, unsigned int to) +{ + unsigned int block_start, block_end; + struct buffer_head *bh, *head; + unsigned int nc = 0; + + for (bh = head = page_buffers(page), block_start = 0; + bh != head || !block_start; + block_start = block_end, bh = bh->b_this_page) { + block_end = block_start + bh->b_size; + if (block_end > from && block_start < to && !buffer_dirty(bh)) + nc++; + } + return nc; +} + +/* + * NILFS2 needs clear_page_dirty() in the following two cases: + * + * 1) For B-tree node pages and data pages of DAT file, NILFS2 clears dirty + * flag of pages when it copies back pages from shadow cache to the + * original cache. + * + * 2) Some B-tree operations like insertion or deletion may dispose buffers + * in dirty state, and this needs to cancel the dirty state of their pages. + */ +int __nilfs_clear_page_dirty(struct page *page) +{ + struct address_space *mapping = page->mapping; + + if (mapping) { + xa_lock_irq(&mapping->i_pages); + if (test_bit(PG_dirty, &page->flags)) { + __xa_clear_mark(&mapping->i_pages, page_index(page), + PAGECACHE_TAG_DIRTY); + xa_unlock_irq(&mapping->i_pages); + return clear_page_dirty_for_io(page); + } + xa_unlock_irq(&mapping->i_pages); + return 0; + } + return TestClearPageDirty(page); +} + +/** + * nilfs_find_uncommitted_extent - find extent of uncommitted data + * @inode: inode + * @start_blk: start block offset (in) + * @blkoff: start offset of the found extent (out) + * + * This function searches an extent of buffers marked "delayed" which + * starts from a block offset equal to or larger than @start_blk. If + * such an extent was found, this will store the start offset in + * @blkoff and return its length in blocks. Otherwise, zero is + * returned. + */ +unsigned long nilfs_find_uncommitted_extent(struct inode *inode, + sector_t start_blk, + sector_t *blkoff) +{ + unsigned int i, nr_folios; + pgoff_t index; + unsigned long length = 0; + struct folio_batch fbatch; + struct folio *folio; + + if (inode->i_mapping->nrpages == 0) + return 0; + + index = start_blk >> (PAGE_SHIFT - inode->i_blkbits); + + folio_batch_init(&fbatch); + +repeat: + nr_folios = filemap_get_folios_contig(inode->i_mapping, &index, ULONG_MAX, + &fbatch); + if (nr_folios == 0) + return length; + + i = 0; + do { + folio = fbatch.folios[i]; + + folio_lock(folio); + if (folio_buffers(folio)) { + struct buffer_head *bh, *head; + sector_t b; + + b = folio->index << (PAGE_SHIFT - inode->i_blkbits); + bh = head = folio_buffers(folio); + do { + if (b < start_blk) + continue; + if (buffer_delay(bh)) { + if (length == 0) + *blkoff = b; + length++; + } else if (length > 0) { + goto out_locked; + } + } while (++b, bh = bh->b_this_page, bh != head); + } else { + if (length > 0) + goto out_locked; + } + folio_unlock(folio); + + } while (++i < nr_folios); + + folio_batch_release(&fbatch); + cond_resched(); + goto repeat; + +out_locked: + folio_unlock(folio); + folio_batch_release(&fbatch); + return length; +} |