nilfs2: add routines to roll back state of DAT file

[mv-sheeva.git] / fs / nilfs2 / mdt.c

diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index 73e5da3b097e26a6cfaa67ca6033dab2b2783e80..0066468609dac95c7da02ab146a6680e4be1db32 100644 (file)
--- 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);