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;
58 struct radix_tree_root cache_radix;
59 struct radix_tree_root pinned_radix;
60 struct list_head trans;
61 struct list_head cache;
66 * describes a tree on disk
68 struct ctree_root_info {
69 u64 fsid[2]; /* FS specific uuid */
70 u64 blocknr; /* blocknr of this block */
71 u64 objectid; /* inode number of this root */
72 u64 tree_root; /* the tree root block */
75 u64 snapuuid[2]; /* root specific uuid */
76 } __attribute__ ((__packed__));
79 * the super block basically lists the main trees of the FS
80 * it currently lacks any block count etc etc
82 struct ctree_super_block {
83 struct ctree_root_info root_info;
84 struct ctree_root_info extent_info;
85 } __attribute__ ((__packed__));
88 * A leaf is full of items. The exact type of item is defined by
89 * the key flags parameter. offset and size tell us where to find
90 * the item in the leaf (relative to the start of the data area)
96 } __attribute__ ((__packed__));
99 * leaves have an item area and a data area:
100 * [item0, item1....itemN] [free space] [dataN...data1, data0]
102 * The data is separate from the items to get the keys closer together
105 #define LEAF_DATA_SIZE (CTREE_BLOCKSIZE - sizeof(struct header))
107 struct header header;
109 struct item items[LEAF_DATA_SIZE/sizeof(struct item)];
110 u8 data[CTREE_BLOCKSIZE-sizeof(struct header)];
112 } __attribute__ ((__packed__));
115 * all non-leaf blocks are nodes, they hold only keys and pointers to
119 struct header header;
120 struct key keys[NODEPTRS_PER_BLOCK];
121 u64 blockptrs[NODEPTRS_PER_BLOCK];
122 } __attribute__ ((__packed__));
125 * items in the extent btree are used to record the objectid of the
126 * owner of the block and the number of references
131 } __attribute__ ((__packed__));
134 * ctree_paths remember the path taken from the root down to the leaf.
135 * level 0 is always the leaf, and nodes[1...MAX_LEVEL] will point
136 * to any other levels that are present.
138 * The slots array records the index of the item or block pointer
139 * used while walking the tree.
142 struct tree_buffer *nodes[MAX_LEVEL];
143 int slots[MAX_LEVEL];
146 struct tree_buffer *alloc_free_block(struct ctree_root *root);
147 int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf);
148 int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks);
149 int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p, int ins_len, int cow);
150 void release_path(struct ctree_root *root, struct ctree_path *p);
151 void init_path(struct ctree_path *p);
152 int del_item(struct ctree_root *root, struct ctree_path *path);
153 int insert_item(struct ctree_root *root, struct key *key, void *data, int data_size);
154 int next_leaf(struct ctree_root *root, struct ctree_path *path);
155 int leaf_free_space(struct leaf *leaf);
156 int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap);
157 int btrfs_finish_extent_commit(struct ctree_root *root);