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 __le64 fsid[2]; /* FS specific uuid */
29 __le64 blocknr; /* which block this node is supposed to live in */
30 __le64 parentid; /* objectid of the tree root */
35 /* generation flags to be added */
36 } __attribute__ ((__packed__));
39 #define NODEPTRS_PER_BLOCK ((CTREE_BLOCKSIZE - sizeof(struct btrfs_header)) / \
40 (sizeof(struct key) + sizeof(u64)))
45 * in ram representation of the tree. extent_root is used for all allocations
46 * and for the extent tree extent_root root. current_insert is used
47 * only for the extent tree.
50 struct tree_buffer *node;
51 struct tree_buffer *commit_root;
52 struct ctree_root *extent_root;
53 struct key current_insert;
54 struct key last_insert;
56 struct radix_tree_root cache_radix;
57 struct radix_tree_root pinned_radix;
58 struct list_head trans;
59 struct list_head cache;
64 * describes a tree on disk
66 struct ctree_root_info {
67 u64 fsid[2]; /* FS specific uuid */
68 u64 blocknr; /* blocknr of this block */
69 u64 objectid; /* inode number of this root */
70 u64 tree_root; /* the tree root block */
73 u64 snapuuid[2]; /* root specific uuid */
74 } __attribute__ ((__packed__));
77 * the super block basically lists the main trees of the FS
78 * it currently lacks any block count etc etc
80 struct ctree_super_block {
81 struct ctree_root_info root_info;
82 struct ctree_root_info extent_info;
83 } __attribute__ ((__packed__));
86 * A leaf is full of items. The exact type of item is defined by
87 * the key flags parameter. offset and size tell us where to find
88 * the item in the leaf (relative to the start of the data area)
94 } __attribute__ ((__packed__));
97 * leaves have an item area and a data area:
98 * [item0, item1....itemN] [free space] [dataN...data1, data0]
100 * The data is separate from the items to get the keys closer together
103 #define LEAF_DATA_SIZE (CTREE_BLOCKSIZE - sizeof(struct btrfs_header))
105 struct btrfs_header header;
107 struct item items[LEAF_DATA_SIZE/sizeof(struct item)];
108 u8 data[CTREE_BLOCKSIZE-sizeof(struct btrfs_header)];
110 } __attribute__ ((__packed__));
113 * all non-leaf blocks are nodes, they hold only keys and pointers to
117 struct btrfs_header header;
118 struct key keys[NODEPTRS_PER_BLOCK];
119 u64 blockptrs[NODEPTRS_PER_BLOCK];
120 } __attribute__ ((__packed__));
123 * items in the extent btree are used to record the objectid of the
124 * owner of the block and the number of references
129 } __attribute__ ((__packed__));
132 * ctree_paths remember the path taken from the root down to the leaf.
133 * level 0 is always the leaf, and nodes[1...MAX_LEVEL] will point
134 * to any other levels that are present.
136 * The slots array records the index of the item or block pointer
137 * used while walking the tree.
140 struct tree_buffer *nodes[MAX_LEVEL];
141 int slots[MAX_LEVEL];
144 static inline u64 btrfs_header_blocknr(struct btrfs_header *h)
146 return le64_to_cpu(h->blocknr);
149 static inline void btrfs_set_header_blocknr(struct btrfs_header *h, u64 blocknr)
151 h->blocknr = cpu_to_le64(blocknr);
154 static inline u64 btrfs_header_parentid(struct btrfs_header *h)
156 return le64_to_cpu(h->parentid);
159 static inline void btrfs_set_header_parentid(struct btrfs_header *h,
162 h->parentid = cpu_to_le64(parentid);
165 static inline u16 btrfs_header_nritems(struct btrfs_header *h)
167 return le16_to_cpu(h->nritems);
170 static inline void btrfs_set_header_nritems(struct btrfs_header *h, u16 val)
172 h->nritems = cpu_to_le16(val);
175 static inline u16 btrfs_header_flags(struct btrfs_header *h)
177 return le16_to_cpu(h->flags);
180 static inline void btrfs_set_header_flags(struct btrfs_header *h, u16 val)
182 h->flags = cpu_to_le16(val);
185 static inline int btrfs_header_level(struct btrfs_header *h)
187 return btrfs_header_flags(h) & (MAX_LEVEL - 1);
190 static inline void btrfs_set_header_level(struct btrfs_header *h, int level)
193 BUG_ON(level > MAX_LEVEL);
194 flags = btrfs_header_flags(h) & ~(MAX_LEVEL - 1);
195 btrfs_set_header_flags(h, flags | level);
198 static inline int btrfs_is_leaf(struct node *n)
200 return (btrfs_header_level(&n->header) == 0);
203 struct tree_buffer *alloc_free_block(struct ctree_root *root);
204 int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf);
205 int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks);
206 int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p, int ins_len, int cow);
207 void release_path(struct ctree_root *root, struct ctree_path *p);
208 void init_path(struct ctree_path *p);
209 int del_item(struct ctree_root *root, struct ctree_path *path);
210 int insert_item(struct ctree_root *root, struct key *key, void *data, int data_size);
211 int next_leaf(struct ctree_root *root, struct ctree_path *path);
212 int leaf_free_space(struct leaf *leaf);
213 int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap);
214 int btrfs_finish_extent_commit(struct ctree_root *root);