From d9c9960f8d4bf1ca9b1b491f1f5de5475515dbfc Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Tue, 13 Mar 2007 16:47:54 -0400 Subject: Change the super to point to a tree of trees to enable persistent snapshots --- disk-io.c | 135 +++++++++++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 107 insertions(+), 28 deletions(-) (limited to 'disk-io.c') diff --git a/disk-io.c b/disk-io.c index c34c0c60..3d4bf683 100644 --- a/disk-io.c +++ b/disk-io.c @@ -154,41 +154,96 @@ static int __commit_transaction(struct btrfs_root *root) return ret; } +static int commit_extent_and_tree_roots(struct btrfs_root *tree_root, + struct btrfs_root *extent_root) +{ + int ret; + u64 old_extent_block; + + while(1) { + old_extent_block = btrfs_root_blocknr(&extent_root->root_item); + if (old_extent_block == extent_root->node->blocknr) + break; + btrfs_set_root_blocknr(&extent_root->root_item, + extent_root->node->blocknr); + ret = btrfs_update_root(tree_root, + &extent_root->root_key, + &extent_root->root_item); + BUG_ON(ret); + } + __commit_transaction(extent_root); + __commit_transaction(tree_root); + return 0; +} + int btrfs_commit_transaction(struct btrfs_root *root, struct btrfs_super_block *s) { int ret = 0; + struct btrfs_buffer *snap = root->commit_root; + struct btrfs_key snap_key; ret = __commit_transaction(root); - if (!ret && root != root->extent_root) - ret = __commit_transaction(root->extent_root); BUG_ON(ret); - if (root->commit_root != root->node) { - struct btrfs_buffer *snap = root->commit_root; - root->commit_root = root->node; - root->node->count++; - ret = btrfs_drop_snapshot(root, snap); - BUG_ON(ret); - // btrfs_block_release(root, snap); - } + + if (root->commit_root == root->node) + return 0; + + memcpy(&snap_key, &root->root_key, sizeof(snap_key)); + root->root_key.offset++; + + btrfs_set_root_blocknr(&root->root_item, root->node->blocknr); + ret = btrfs_insert_root(root->tree_root, &root->root_key, + &root->root_item); + BUG_ON(ret); + + ret = commit_extent_and_tree_roots(root->tree_root, root->extent_root); + BUG_ON(ret); + write_ctree_super(root, s); - btrfs_finish_extent_commit(root); + btrfs_finish_extent_commit(root->extent_root); + btrfs_finish_extent_commit(root->tree_root); + + root->commit_root = root->node; + root->node->count++; + ret = btrfs_drop_snapshot(root, snap); + BUG_ON(ret); + + ret = btrfs_del_root(root->tree_root, &snap_key); + BUG_ON(ret); + return ret; } -static int __setup_root(struct btrfs_root *root, struct btrfs_root *extent_root, - struct btrfs_root_info *info, int fp) +static int __setup_root(struct btrfs_root *root, u64 objectid, int fp) { INIT_LIST_HEAD(&root->trans); INIT_LIST_HEAD(&root->cache); root->cache_size = 0; root->fp = fp; root->node = NULL; - root->extent_root = extent_root; root->commit_root = NULL; - root->node = read_tree_block(root, info->tree_root); memset(&root->current_insert, 0, sizeof(root->current_insert)); memset(&root->last_insert, 0, sizeof(root->last_insert)); + memset(&root->root_key, 0, sizeof(root->root_key)); + memset(&root->root_item, 0, sizeof(root->root_item)); + return 0; +} + +static int find_and_setup_root(struct btrfs_root *tree_root, u64 objectid, + struct btrfs_root *root, int fp) +{ + int ret; + + __setup_root(root, objectid, fp); + ret = btrfs_find_last_root(tree_root, objectid, + &root->root_item, &root->root_key); + BUG_ON(ret); + + root->node = read_tree_block(root, + btrfs_root_blocknr(&root->root_item)); + root->ref_cows = 0; + BUG_ON(!root->node); return 0; } @@ -196,9 +251,19 @@ struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super) { struct btrfs_root *root = malloc(sizeof(struct btrfs_root)); struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root)); + struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root)); int fp; int ret; + root->extent_root = extent_root; + root->tree_root = tree_root; + + extent_root->extent_root = extent_root; + extent_root->tree_root = tree_root; + + tree_root->extent_root = extent_root; + tree_root->tree_root = tree_root; + fp = open(filename, O_CREAT | O_RDWR, 0600); if (fp < 0) { free(root); @@ -208,11 +273,14 @@ struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super) INIT_RADIX_TREE(&root->pinned_radix, GFP_KERNEL); INIT_RADIX_TREE(&extent_root->pinned_radix, GFP_KERNEL); INIT_RADIX_TREE(&extent_root->cache_radix, GFP_KERNEL); + INIT_RADIX_TREE(&tree_root->pinned_radix, GFP_KERNEL); + INIT_RADIX_TREE(&tree_root->cache_radix, GFP_KERNEL); + ret = pread(fp, super, sizeof(struct btrfs_super_block), BTRFS_SUPER_INFO_OFFSET(BTRFS_BLOCKSIZE)); - if (ret == 0 || super->root_info.tree_root == 0) { + if (ret == 0 || btrfs_super_root(super) == 0) { printf("making new FS!\n"); - ret = mkfs(fp); + ret = mkfs(fp, 0, BTRFS_BLOCKSIZE); if (ret) return NULL; ret = pread(fp, super, sizeof(struct btrfs_super_block), @@ -221,24 +289,29 @@ struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super) return NULL; } BUG_ON(ret < 0); - __setup_root(root, extent_root, &super->root_info, fp); - __setup_root(extent_root, extent_root, &super->extent_info, fp); + + __setup_root(tree_root, BTRFS_ROOT_TREE_OBJECTID, fp); + tree_root->node = read_tree_block(tree_root, btrfs_super_root(super)); + BUG_ON(!tree_root->node); + + ret = find_and_setup_root(tree_root, BTRFS_EXTENT_TREE_OBJECTID, + extent_root, fp); + BUG_ON(ret); + + ret = find_and_setup_root(tree_root, BTRFS_FS_TREE_OBJECTID, + root, fp); + BUG_ON(ret); + root->commit_root = root->node; root->node->count++; + root->ref_cows = 1; return root; } -static int __update_root(struct btrfs_root *root, struct btrfs_root_info *info) -{ - info->tree_root = root->node->blocknr; - return 0; -} - int write_ctree_super(struct btrfs_root *root, struct btrfs_super_block *s) { int ret; - __update_root(root, &s->root_info); - __update_root(root->extent_root, &s->extent_info); + btrfs_set_super_root(s, root->tree_root->node->blocknr); ret = pwrite(root->fp, s, sizeof(*s), BTRFS_SUPER_INFO_OFFSET(BTRFS_BLOCKSIZE)); if (ret != sizeof(*s)) { @@ -260,19 +333,25 @@ static int drop_cache(struct btrfs_root *root) } int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s) { + int ret; btrfs_commit_transaction(root, s); - __commit_transaction(root->extent_root); + ret = commit_extent_and_tree_roots(root->tree_root, root->extent_root); + BUG_ON(ret); write_ctree_super(root, s); drop_cache(root->extent_root); + drop_cache(root->tree_root); drop_cache(root); BUG_ON(!list_empty(&root->trans)); BUG_ON(!list_empty(&root->extent_root->trans)); + BUG_ON(!list_empty(&root->tree_root->trans)); close(root->fp); if (root->node) btrfs_block_release(root, root->node); if (root->extent_root->node) btrfs_block_release(root->extent_root, root->extent_root->node); + if (root->tree_root->node) + btrfs_block_release(root->tree_root, root->tree_root->node); btrfs_block_release(root, root->commit_root); free(root); printf("on close %d blocks are allocated\n", allocated_blocks); -- cgit v1.2.3