6 #define CTREE_BLOCKSIZE 1024
9 * the key defines the order in the tree, and so it also defines (optimal)
10 * block layout. objectid corresonds to the inode number. The flags
11 * tells us things about the object, and is a kind of stream selector.
12 * so for a given inode, keys with flags of 1 might refer to the inode
13 * data, flags of 2 may point to file data in the btree and flags == 3
14 * may point to extents.
16 * offset is the starting byte offset for this key in the stream.
22 } __attribute__ ((__packed__));
25 * every tree block (leaf or node) starts with this header.
28 u64 fsid[2]; /* FS specific uuid */
29 u64 blocknr; /* which block this node is supposed to live in */
30 u64 parentid; /* objectid of the tree root */
35 /* generation flags to be added */
36 } __attribute__ ((__packed__));
38 #define NODEPTRS_PER_BLOCK ((CTREE_BLOCKSIZE - sizeof(struct header)) / \
39 (sizeof(struct key) + sizeof(u64)))
42 #define node_level(f) ((f) & (MAX_LEVEL-1))
43 #define is_leaf(f) (node_level(f) == 0)
48 * in ram representation of the tree. extent_root is used for all allocations
49 * and for the extent tree extent_root root. current_insert is used
50 * only for the extent tree.
53 struct tree_buffer *node;
54 struct tree_buffer *commit_root;
55 struct ctree_root *extent_root;
56 struct key current_insert;
57 struct key last_insert;
59 struct radix_tree_root cache_radix;
60 struct radix_tree_root pinned_radix;
61 struct list_head trans;
62 struct list_head cache;
67 * describes a tree on disk
69 struct ctree_root_info {
70 u64 fsid[2]; /* FS specific uuid */
71 u64 blocknr; /* blocknr of this block */
72 u64 objectid; /* inode number of this root */
73 u64 tree_root; /* the tree root block */
76 u64 snapuuid[2]; /* root specific uuid */
77 } __attribute__ ((__packed__));
80 * the super block basically lists the main trees of the FS
81 * it currently lacks any block count etc etc
83 struct ctree_super_block {
84 struct ctree_root_info root_info;
85 struct ctree_root_info extent_info;
86 } __attribute__ ((__packed__));
89 * A leaf is full of items. The exact type of item is defined by
90 * the key flags parameter. offset and size tell us where to find
91 * the item in the leaf (relative to the start of the data area)
97 } __attribute__ ((__packed__));
100 * leaves have an item area and a data area:
101 * [item0, item1....itemN] [free space] [dataN...data1, data0]
103 * The data is separate from the items to get the keys closer together
106 #define LEAF_DATA_SIZE (CTREE_BLOCKSIZE - sizeof(struct header))
108 struct header header;
110 struct item items[LEAF_DATA_SIZE/sizeof(struct item)];
111 u8 data[CTREE_BLOCKSIZE-sizeof(struct header)];
113 } __attribute__ ((__packed__));
116 * all non-leaf blocks are nodes, they hold only keys and pointers to
120 struct header header;
121 struct key keys[NODEPTRS_PER_BLOCK];
122 u64 blockptrs[NODEPTRS_PER_BLOCK];
123 } __attribute__ ((__packed__));
126 * items in the extent btree are used to record the objectid of the
127 * owner of the block and the number of references
132 } __attribute__ ((__packed__));
135 * ctree_paths remember the path taken from the root down to the leaf.
136 * level 0 is always the leaf, and nodes[1...MAX_LEVEL] will point
137 * to any other levels that are present.
139 * The slots array records the index of the item or block pointer
140 * used while walking the tree.
143 struct tree_buffer *nodes[MAX_LEVEL];
144 int slots[MAX_LEVEL];
147 struct tree_buffer *alloc_free_block(struct ctree_root *root);
148 int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf);
149 int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks);
150 int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p, int ins_len, int cow);
151 void release_path(struct ctree_root *root, struct ctree_path *p);
152 void init_path(struct ctree_path *p);
153 int del_item(struct ctree_root *root, struct ctree_path *path);
154 int insert_item(struct ctree_root *root, struct key *key, void *data, int data_size);
155 int next_leaf(struct ctree_root *root, struct ctree_path *path);
156 int leaf_free_space(struct leaf *leaf);
157 int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap);
158 int btrfs_finish_extent_commit(struct ctree_root *root);