From ebdfed4dc59d177cf26013a0c9b8ee9652e9a140 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Mon, 6 Sep 2010 12:05:43 +0900 Subject: [PATCH] nilfs2: add routines to roll back state of DAT file This adds optional function to metadata files which makes a copy of bmap, page caches, and b-tree node cache, and rolls back to the copy as needed. This enhancement is intended to displace gcdat inode that provides a similar function in a different way. In this patch, nilfs_shadow_map structure is added to store a copy of the foregoing states. nilfs_mdt_setup_shadow_map relates this structure to a metadata file. And, nilfs_mdt_save_to_shadow_map() and nilfs_mdt_restore_from_shadow_map() provides save and restore functions respectively. Finally, nilfs_mdt_clear_shadow_map() clears states of nilfs_shadow_map. The copy of b-tree node cache and page cache is made by duplicating only dirty pages into corresponding caches in nilfs_shadow_map. Their restoration is done by clearing dirty pages from original caches and by copying dirty pages back from nilfs_shadow_map. Signed-off-by: Ryusuke Konishi --- fs/nilfs2/btnode.c | 17 +------- fs/nilfs2/mdt.c | 104 +++++++++++++++++++++++++++++++++++++++++++-- fs/nilfs2/mdt.h | 14 ++++++ fs/nilfs2/page.c | 25 +++++++++++ fs/nilfs2/page.h | 4 ++ 5 files changed, 145 insertions(+), 19 deletions(-) diff --git a/fs/nilfs2/btnode.c b/fs/nilfs2/btnode.c index f78ab1044d1d..5115814cb745 100644 --- a/fs/nilfs2/btnode.c +++ b/fs/nilfs2/btnode.c @@ -37,15 +37,7 @@ void nilfs_btnode_cache_init_once(struct address_space *btnc) { - memset(btnc, 0, sizeof(*btnc)); - INIT_RADIX_TREE(&btnc->page_tree, GFP_ATOMIC); - spin_lock_init(&btnc->tree_lock); - INIT_LIST_HEAD(&btnc->private_list); - spin_lock_init(&btnc->private_lock); - - spin_lock_init(&btnc->i_mmap_lock); - INIT_RAW_PRIO_TREE_ROOT(&btnc->i_mmap); - INIT_LIST_HEAD(&btnc->i_mmap_nonlinear); + nilfs_mapping_init_once(btnc); } static const struct address_space_operations def_btnode_aops = { @@ -55,12 +47,7 @@ static const struct address_space_operations def_btnode_aops = { void nilfs_btnode_cache_init(struct address_space *btnc, struct backing_dev_info *bdi) { - btnc->host = NULL; /* can safely set to host inode ? */ - btnc->flags = 0; - mapping_set_gfp_mask(btnc, GFP_NOFS); - btnc->assoc_mapping = NULL; - btnc->backing_dev_info = bdi; - btnc->a_ops = &def_btnode_aops; + nilfs_mapping_init(btnc, bdi, &def_btnode_aops); } void nilfs_btnode_cache_clear(struct address_space *btnc) diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c index 73e5da3b097e..0066468609da 100644 --- a/fs/nilfs2/mdt.c +++ b/fs/nilfs2/mdt.c @@ -398,16 +398,22 @@ int nilfs_mdt_fetch_dirty(struct inode *inode) static int nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc) { - struct inode *inode = container_of(page->mapping, - struct inode, i_data); - struct super_block *sb = inode->i_sb; - struct the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs; + struct inode *inode; + struct super_block *sb; + struct the_nilfs *nilfs; struct nilfs_sb_info *writer = NULL; int err = 0; redirty_page_for_writepage(wbc, page); unlock_page(page); + inode = page->mapping->host; + if (!inode) + return 0; + + sb = inode->i_sb; + nilfs = NILFS_MDT(inode)->mi_nilfs; + if (page->mapping->assoc_mapping) return 0; /* Do not request flush for shadow page cache */ if (!sb) { @@ -567,6 +573,96 @@ void nilfs_mdt_set_shadow(struct inode *orig, struct inode *shadow) &NILFS_I(orig)->i_btnode_cache; } +static const struct address_space_operations shadow_map_aops = { + .sync_page = block_sync_page, +}; + +/** + * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file + * @inode: inode of the metadata file + * @shadow: shadow mapping + */ +int nilfs_mdt_setup_shadow_map(struct inode *inode, + struct nilfs_shadow_map *shadow) +{ + struct nilfs_mdt_info *mi = NILFS_MDT(inode); + struct backing_dev_info *bdi = NILFS_I_NILFS(inode)->ns_bdi; + + INIT_LIST_HEAD(&shadow->frozen_buffers); + nilfs_mapping_init_once(&shadow->frozen_data); + nilfs_mapping_init(&shadow->frozen_data, bdi, &shadow_map_aops); + nilfs_mapping_init_once(&shadow->frozen_btnodes); + nilfs_mapping_init(&shadow->frozen_btnodes, bdi, &shadow_map_aops); + mi->mi_shadow = shadow; + return 0; +} + +/** + * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map + * @inode: inode of the metadata file + */ +int nilfs_mdt_save_to_shadow_map(struct inode *inode) +{ + struct nilfs_mdt_info *mi = NILFS_MDT(inode); + struct nilfs_inode_info *ii = NILFS_I(inode); + struct nilfs_shadow_map *shadow = mi->mi_shadow; + int ret; + + ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping); + if (ret) + goto out; + + ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes, + &ii->i_btnode_cache); + if (ret) + goto out; + + nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store); + out: + return ret; +} + +/** + * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state + * @inode: inode of the metadata file + */ +void nilfs_mdt_restore_from_shadow_map(struct inode *inode) +{ + struct nilfs_mdt_info *mi = NILFS_MDT(inode); + struct nilfs_inode_info *ii = NILFS_I(inode); + struct nilfs_shadow_map *shadow = mi->mi_shadow; + + down_write(&mi->mi_sem); + + if (mi->mi_palloc_cache) + nilfs_palloc_clear_cache(inode); + + nilfs_clear_dirty_pages(inode->i_mapping); + nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data); + + nilfs_clear_dirty_pages(&ii->i_btnode_cache); + nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes); + + nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store); + + up_write(&mi->mi_sem); +} + +/** + * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches + * @inode: inode of the metadata file + */ +void nilfs_mdt_clear_shadow_map(struct inode *inode) +{ + struct nilfs_mdt_info *mi = NILFS_MDT(inode); + struct nilfs_shadow_map *shadow = mi->mi_shadow; + + down_write(&mi->mi_sem); + truncate_inode_pages(&shadow->frozen_data, 0); + truncate_inode_pages(&shadow->frozen_btnodes, 0); + up_write(&mi->mi_sem); +} + static void nilfs_mdt_clear(struct inode *inode) { struct nilfs_inode_info *ii = NILFS_I(inode); diff --git a/fs/nilfs2/mdt.h b/fs/nilfs2/mdt.h index f44560224bd1..e7f0d158c527 100644 --- a/fs/nilfs2/mdt.h +++ b/fs/nilfs2/mdt.h @@ -28,6 +28,13 @@ #include "nilfs.h" #include "page.h" +struct nilfs_shadow_map { + struct nilfs_bmap_store bmap_store; + struct address_space frozen_data; + struct address_space frozen_btnodes; + struct list_head frozen_buffers; +}; + /** * struct nilfs_mdt_info - on-memory private data of meta data files * @mi_nilfs: back pointer to the_nilfs struct @@ -37,6 +44,7 @@ * @mi_first_entry_offset: offset to the first entry * @mi_entries_per_block: number of entries in a block * @mi_palloc_cache: persistent object allocator cache + * @mi_shadow: shadow of bmap and page caches * @mi_blocks_per_group: number of blocks in a group * @mi_blocks_per_desc_block: number of blocks per descriptor block */ @@ -48,6 +56,7 @@ struct nilfs_mdt_info { unsigned mi_first_entry_offset; unsigned long mi_entries_per_block; struct nilfs_palloc_cache *mi_palloc_cache; + struct nilfs_shadow_map *mi_shadow; unsigned long mi_blocks_per_group; unsigned long mi_blocks_per_desc_block; }; @@ -86,6 +95,11 @@ void nilfs_mdt_destroy(struct inode *); void nilfs_mdt_set_entry_size(struct inode *, unsigned, unsigned); void nilfs_mdt_set_shadow(struct inode *, struct inode *); +int nilfs_mdt_setup_shadow_map(struct inode *inode, + struct nilfs_shadow_map *shadow); +int nilfs_mdt_save_to_shadow_map(struct inode *inode); +void nilfs_mdt_restore_from_shadow_map(struct inode *inode); +void nilfs_mdt_clear_shadow_map(struct inode *inode); #define nilfs_mdt_mark_buffer_dirty(bh) nilfs_mark_buffer_dirty(bh) diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c index aab11db2cb08..6384ac14c0c8 100644 --- a/fs/nilfs2/page.c +++ b/fs/nilfs2/page.c @@ -513,6 +513,31 @@ unsigned nilfs_page_count_clean_buffers(struct page *page, } return nc; } + +void nilfs_mapping_init_once(struct address_space *mapping) +{ + memset(mapping, 0, sizeof(*mapping)); + INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC); + spin_lock_init(&mapping->tree_lock); + INIT_LIST_HEAD(&mapping->private_list); + spin_lock_init(&mapping->private_lock); + + spin_lock_init(&mapping->i_mmap_lock); + INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap); + INIT_LIST_HEAD(&mapping->i_mmap_nonlinear); +} + +void nilfs_mapping_init(struct address_space *mapping, + struct backing_dev_info *bdi, + const struct address_space_operations *aops) +{ + mapping->host = NULL; + mapping->flags = 0; + mapping_set_gfp_mask(mapping, GFP_NOFS); + mapping->assoc_mapping = NULL; + mapping->backing_dev_info = bdi; + mapping->a_ops = aops; +} /* * NILFS2 needs clear_page_dirty() in the following two cases: diff --git a/fs/nilfs2/page.h b/fs/nilfs2/page.h index f53d8da41ed7..6ec4f498fc2b 100644 --- a/fs/nilfs2/page.h +++ b/fs/nilfs2/page.h @@ -59,6 +59,10 @@ 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 *); +void nilfs_mapping_init_once(struct address_space *mapping); +void nilfs_mapping_init(struct address_space *mapping, + struct backing_dev_info *bdi, + const struct address_space_operations *aops); unsigned nilfs_page_count_clean_buffers(struct page *, unsigned, unsigned); #define NILFS_PAGE_BUG(page, m, a...) \ -- 2.20.1