diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nilfs2/page.c | 542 | ||||
| -rw-r--r-- | fs/nilfs2/page.h | 76 |
2 files changed, 618 insertions, 0 deletions
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c new file mode 100644 index 0000000..7b18be8 --- /dev/null +++ b/fs/nilfs2/page.c @@ -0,0 +1,542 @@ +/* + * page.c - buffer/page management specific to NILFS + * + * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * Written by Ryusuke Konishi <ryusuke@osrg.net>, + * Seiji Kihara <kihara@osrg.net>. + */ + +#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 "nilfs.h" +#include "page.h" +#include "mdt.h" + + +#define NILFS_BUFFER_INHERENT_BITS \ + ((1UL << BH_Uptodate) | (1UL << BH_Mapped) | (1UL << BH_NILFS_Node) | \ + (1UL << BH_NILFS_Volatile) | (1UL << BH_NILFS_Allocated)) + +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_CACHE_SHIFT - blkbits); + bh = nilfs_page_get_nth_block(page, block - first_block); + + touch_buffer(bh); + wait_on_buffer(bh); + return bh; +} + +/* + * Since the page cache of B-tree node pages or data page cache of pseudo + * inodes does not have a valid mapping->host pointer, calling + * mark_buffer_dirty() for their buffers causes a NULL pointer dereference; + * it calls __mark_inode_dirty(NULL) through __set_page_dirty(). + * To avoid this problem, the old style mark_buffer_dirty() is used instead. + */ +void nilfs_mark_buffer_dirty(struct buffer_head *bh) +{ + if (!buffer_dirty(bh) && !test_set_buffer_dirty(bh)) + __set_page_dirty_nobuffers(bh->b_page); +} + +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_CACHE_SHIFT - blkbits); + struct page *page, *opage; + struct buffer_head *bh, *obh; + + 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); + page_cache_release(page); + return NULL; + } + if (!buffer_uptodate(bh) && mapping->assoc_mapping != NULL) { + /* + * Shadow page cache uses assoc_mapping to point its original + * page cache. The following code tries the original cache + * if the given cache is a shadow and it didn't hit. + */ + opage = find_lock_page(mapping->assoc_mapping, index); + if (!opage) + return bh; + + obh = __nilfs_get_page_block(opage, blkoff, index, blkbits, + b_state); + if (buffer_uptodate(obh)) { + nilfs_copy_buffer(bh, obh); + if (buffer_dirty(obh)) { + nilfs_mark_buffer_dirty(bh); + if (!buffer_nilfs_node(bh) && NILFS_MDT(inode)) + nilfs_mdt_mark_dirty(inode); + } + } + brelse(obh); + unlock_page(opage); + page_cache_release(opage); + } + return bh; +} + +/** + * nilfs_forget_buffer - discard dirty state + * @inode: owner inode of the buffer + * @bh: buffer head of the buffer to be discarded + */ +void nilfs_forget_buffer(struct buffer_head *bh) +{ + struct page *page = bh->b_page; + + lock_buffer(bh); + clear_buffer_nilfs_volatile(bh); + if (test_clear_buffer_dirty(bh) && nilfs_page_buffers_clean(page)) + __nilfs_clear_page_dirty(page); + + clear_buffer_uptodate(bh); + clear_buffer_mapped(bh); + 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, KM_USER0); + kaddr1 = kmap_atomic(dpage, KM_USER1); + memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size); + kunmap_atomic(kaddr1, KM_USER1); + kunmap_atomic(kaddr0, KM_USER0); + + 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 & ((1UL << BH_Uptodate) | (1UL << BH_Mapped)); + while ((bh = bh->b_this_page) != dbh) { + lock_buffer(bh); + bits &= bh->b_state; + unlock_buffer(bh); + } + if (bits & (1UL << BH_Uptodate)) + SetPageUptodate(dpage); + else + ClearPageUptodate(dpage); + if (bits & (1UL << 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 = 0; + + if (unlikely(!page)) { + printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n"); + return; + } + + m = page->mapping; + if (m) { + struct inode *inode = NILFS_AS_I(m); + if (inode != NULL) + ino = inode->i_ino; + } + printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx " + "mapping=%p ino=%lu\n", + page, atomic_read(&page->_count), + (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_alloc_private_page - allocate a private page with buffer heads + * + * Return Value: On success, a pointer to the allocated page is returned. + * On error, NULL is returned. + */ +struct page *nilfs_alloc_private_page(struct block_device *bdev, int size, + unsigned long state) +{ + struct buffer_head *bh, *head, *tail; + struct page *page; + + page = alloc_page(GFP_NOFS); /* page_count of the returned page is 1 */ + if (unlikely(!page)) + return NULL; + + lock_page(page); + head = alloc_page_buffers(page, size, 0); + if (unlikely(!head)) { + unlock_page(page); + __free_page(page); + return NULL; + } + + bh = head; + do { + bh->b_state = (1UL << BH_NILFS_Allocated) | state; + tail = bh; + bh->b_bdev = bdev; + bh = bh->b_this_page; + } while (bh); + + tail->b_this_page = head; + attach_page_buffers(page, head); + + return page; +} + +void nilfs_free_private_page(struct page *page) +{ + BUG_ON(!PageLocked(page)); + BUG_ON(page->mapping); + + if (page_has_buffers(page) && !try_to_free_buffers(page)) + NILFS_PAGE_BUG(page, "failed to free page"); + + unlock_page(page); + __free_page(page); +} + +/** + * 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 fuction 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, *sbufs; + unsigned long mask = NILFS_BUFFER_INHERENT_BITS; + + BUG_ON(PageWriteback(dst)); + + sbh = sbufs = page_buffers(src); + if (!page_has_buffers(dst)) + create_empty_buffers(dst, sbh->b_size, 0); + + if (copy_dirty) + mask |= (1UL << 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 pagevec pvec; + unsigned int i; + pgoff_t index = 0; + int err = 0; + + pagevec_init(&pvec, 0); +repeat: + if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY, + PAGEVEC_SIZE)) + return 0; + + for (i = 0; i < pagevec_count(&pvec); i++) { + struct page *page = pvec.pages[i], *dpage; + + lock_page(page); + if (unlikely(!PageDirty(page))) + NILFS_PAGE_BUG(page, "inconsistent dirty state"); + + dpage = grab_cache_page(dmap, page->index); + if (unlikely(!dpage)) { + /* No empty page is added to the page cache */ + err = -ENOMEM; + unlock_page(page); + break; + } + if (unlikely(!page_has_buffers(page))) + NILFS_PAGE_BUG(page, + "found empty page in dat page cache"); + + nilfs_copy_page(dpage, page, 1); + __set_page_dirty_nobuffers(dpage); + + unlock_page(dpage); + page_cache_release(dpage); + unlock_page(page); + } + pagevec_release(&pvec); + cond_resched(); + + if (likely(!err)) + goto repeat; + return err; +} + +/** + * nilfs_copy_back_pages -- copy back pages to orignal cache from shadow cache + * @dmap: destination page cache + * @smap: source page cache + * + * No pages must no 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 pagevec pvec; + unsigned int i, n; + pgoff_t index = 0; + int err; + + pagevec_init(&pvec, 0); +repeat: + n = pagevec_lookup(&pvec, smap, index, PAGEVEC_SIZE); + if (!n) + return; + index = pvec.pages[n - 1]->index + 1; + + for (i = 0; i < pagevec_count(&pvec); i++) { + struct page *page = pvec.pages[i], *dpage; + pgoff_t offset = page->index; + + lock_page(page); + dpage = find_lock_page(dmap, offset); + if (dpage) { + /* override existing page on the destination cache */ + BUG_ON(PageDirty(dpage)); + nilfs_copy_page(dpage, page, 0); + unlock_page(dpage); + page_cache_release(dpage); + } else { + struct page *page2; + + /* move the page to the destination cache */ + spin_lock_irq(&smap->tree_lock); + page2 = radix_tree_delete(&smap->page_tree, offset); + if (unlikely(page2 != page)) + NILFS_PAGE_BUG(page, "page removal failed " + "(offset=%lu, page2=%p)", + offset, page2); + smap->nrpages--; + spin_unlock_irq(&smap->tree_lock); + + spin_lock_irq(&dmap->tree_lock); + err = radix_tree_insert(&dmap->page_tree, offset, page); + if (unlikely(err < 0)) { + BUG_ON(err == -EEXIST); + page->mapping = NULL; + page_cache_release(page); /* for cache */ + } else { + page->mapping = dmap; + dmap->nrpages++; + if (PageDirty(page)) + radix_tree_tag_set(&dmap->page_tree, + offset, + PAGECACHE_TAG_DIRTY); + } + spin_unlock_irq(&dmap->tree_lock); + } + unlock_page(page); + } + pagevec_release(&pvec); + cond_resched(); + + goto repeat; +} + +void nilfs_clear_dirty_pages(struct address_space *mapping) +{ + struct pagevec pvec; + unsigned int i; + pgoff_t index = 0; + + pagevec_init(&pvec, 0); + + while (pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY, + PAGEVEC_SIZE)) { + for (i = 0; i < pagevec_count(&pvec); i++) { + struct page *page = pvec.pages[i]; + struct buffer_head *bh, *head; + + lock_page(page); + ClearPageUptodate(page); + ClearPageMappedToDisk(page); + bh = head = page_buffers(page); + do { + lock_buffer(bh); + clear_buffer_dirty(bh); + clear_buffer_nilfs_volatile(bh); + clear_buffer_uptodate(bh); + clear_buffer_mapped(bh); + unlock_buffer(bh); + bh = bh->b_this_page; + } while (bh != head); + + __nilfs_clear_page_dirty(page); + unlock_page(page); + } + pagevec_release(&pvec); + cond_resched(); + } +} + +unsigned nilfs_page_count_clean_buffers(struct page *page, + unsigned from, unsigned to) +{ + unsigned block_start, block_end; + struct buffer_head *bh, *head; + unsigned 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 the dat/gcdat, NILFS2 clears + * page dirty flags when it copies back pages from the shadow cache + * (gcdat->{i_mapping,i_btnode_cache}) to its original cache + * (dat->{i_mapping,i_btnode_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) { + spin_lock_irq(&mapping->tree_lock); + if (test_bit(PG_dirty, &page->flags)) { + radix_tree_tag_clear(&mapping->page_tree, + page_index(page), + PAGECACHE_TAG_DIRTY); + spin_unlock_irq(&mapping->tree_lock); + return clear_page_dirty_for_io(page); + } + spin_unlock_irq(&mapping->tree_lock); + return 0; + } + return TestClearPageDirty(page); +} diff --git a/fs/nilfs2/page.h b/fs/nilfs2/page.h new file mode 100644 index 0000000..8abca4d --- /dev/null +++ b/fs/nilfs2/page.h @@ -0,0 +1,76 @@ +/* + * page.h - buffer/page management specific to NILFS + * + * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * Written by Ryusuke Konishi <ryusuke@osrg.net>, + * Seiji Kihara <kihara@osrg.net>. + */ + +#ifndef _NILFS_PAGE_H +#define _NILFS_PAGE_H + +#include <linux/buffer_head.h> +#include "nilfs.h" + +/* + * Extended buffer state bits + */ +enum { + BH_NILFS_Allocated = BH_PrivateStart, + BH_NILFS_Node, + BH_NILFS_Volatile, +}; + +BUFFER_FNS(NILFS_Allocated, nilfs_allocated) /* nilfs private buffers */ +BUFFER_FNS(NILFS_Node, nilfs_node) /* nilfs node buffers */ +BUFFER_FNS(NILFS_Volatile, nilfs_volatile) + + +void nilfs_mark_buffer_dirty(struct buffer_head *bh); +int __nilfs_clear_page_dirty(struct page *); + +struct buffer_head *nilfs_grab_buffer(struct inode *, struct address_space *, + unsigned long, unsigned long); +void nilfs_forget_buffer(struct buffer_head *); +void nilfs_copy_buffer(struct buffer_head *, struct buffer_head *); +int nilfs_page_buffers_clean(struct page *); +void nilfs_page_bug(struct page *); +struct page *nilfs_alloc_private_page(struct block_device *, int, + unsigned long); +void nilfs_free_private_page(struct page *); + +int nilfs_copy_dirty_pages(struct address_space *, struct address_space *); +void nilfs_copy_back_pages(struct address_space *, struct address_space *); +void nilfs_clear_dirty_pages(struct address_space *); +unsigned nilfs_page_count_clean_buffers(struct page *, unsigned, unsigned); + +#define NILFS_PAGE_BUG(page, m, a...) \ + do { nilfs_page_bug(page); BUG(); } while (0) + +static inline struct buffer_head * +nilfs_page_get_nth_block(struct page *page, unsigned int count) +{ + struct buffer_head *bh = page_buffers(page); + + while (count-- > 0) + bh = bh->b_this_page; + get_bh(bh); + return bh; +} + +#endif /* _NILFS_PAGE_H */ |
