| 1 | #ifndef __CTREE__ |
| 2 | #define __CTREE__ |
| 3 | |
| 4 | #include "list.h" |
| 5 | |
| 6 | #define CTREE_BLOCKSIZE 1024 |
| 7 | |
| 8 | /* |
| 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. |
| 15 | * |
| 16 | * offset is the starting byte offset for this key in the stream. |
| 17 | */ |
| 18 | struct key { |
| 19 | u64 objectid; |
| 20 | u32 flags; |
| 21 | u64 offset; |
| 22 | } __attribute__ ((__packed__)); |
| 23 | |
| 24 | /* |
| 25 | * every tree block (leaf or node) starts with this header. |
| 26 | */ |
| 27 | struct btrfs_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 */ |
| 31 | __le32 csum; |
| 32 | __le32 ham; |
| 33 | __le16 nritems; |
| 34 | __le16 flags; |
| 35 | /* generation flags to be added */ |
| 36 | } __attribute__ ((__packed__)); |
| 37 | |
| 38 | #define MAX_LEVEL 8 |
| 39 | #define NODEPTRS_PER_BLOCK ((CTREE_BLOCKSIZE - sizeof(struct btrfs_header)) / \ |
| 40 | (sizeof(struct key) + sizeof(u64))) |
| 41 | |
| 42 | struct tree_buffer; |
| 43 | |
| 44 | /* |
| 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. |
| 48 | */ |
| 49 | struct ctree_root { |
| 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; |
| 55 | int fp; |
| 56 | struct radix_tree_root cache_radix; |
| 57 | struct radix_tree_root pinned_radix; |
| 58 | struct list_head trans; |
| 59 | struct list_head cache; |
| 60 | int cache_size; |
| 61 | }; |
| 62 | |
| 63 | /* |
| 64 | * describes a tree on disk |
| 65 | */ |
| 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 */ |
| 71 | u32 csum; |
| 72 | u32 ham; |
| 73 | u64 snapuuid[2]; /* root specific uuid */ |
| 74 | } __attribute__ ((__packed__)); |
| 75 | |
| 76 | /* |
| 77 | * the super block basically lists the main trees of the FS |
| 78 | * it currently lacks any block count etc etc |
| 79 | */ |
| 80 | struct ctree_super_block { |
| 81 | struct ctree_root_info root_info; |
| 82 | struct ctree_root_info extent_info; |
| 83 | } __attribute__ ((__packed__)); |
| 84 | |
| 85 | /* |
| 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) |
| 89 | */ |
| 90 | struct item { |
| 91 | struct key key; |
| 92 | u16 offset; |
| 93 | u16 size; |
| 94 | } __attribute__ ((__packed__)); |
| 95 | |
| 96 | /* |
| 97 | * leaves have an item area and a data area: |
| 98 | * [item0, item1....itemN] [free space] [dataN...data1, data0] |
| 99 | * |
| 100 | * The data is separate from the items to get the keys closer together |
| 101 | * during searches. |
| 102 | */ |
| 103 | #define LEAF_DATA_SIZE (CTREE_BLOCKSIZE - sizeof(struct btrfs_header)) |
| 104 | struct leaf { |
| 105 | struct btrfs_header header; |
| 106 | union { |
| 107 | struct item items[LEAF_DATA_SIZE/sizeof(struct item)]; |
| 108 | u8 data[CTREE_BLOCKSIZE-sizeof(struct btrfs_header)]; |
| 109 | }; |
| 110 | } __attribute__ ((__packed__)); |
| 111 | |
| 112 | /* |
| 113 | * all non-leaf blocks are nodes, they hold only keys and pointers to |
| 114 | * other blocks |
| 115 | */ |
| 116 | struct node { |
| 117 | struct btrfs_header header; |
| 118 | struct key keys[NODEPTRS_PER_BLOCK]; |
| 119 | u64 blockptrs[NODEPTRS_PER_BLOCK]; |
| 120 | } __attribute__ ((__packed__)); |
| 121 | |
| 122 | /* |
| 123 | * items in the extent btree are used to record the objectid of the |
| 124 | * owner of the block and the number of references |
| 125 | */ |
| 126 | struct extent_item { |
| 127 | u32 refs; |
| 128 | u64 owner; |
| 129 | } __attribute__ ((__packed__)); |
| 130 | |
| 131 | /* |
| 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. |
| 135 | * |
| 136 | * The slots array records the index of the item or block pointer |
| 137 | * used while walking the tree. |
| 138 | */ |
| 139 | struct ctree_path { |
| 140 | struct tree_buffer *nodes[MAX_LEVEL]; |
| 141 | int slots[MAX_LEVEL]; |
| 142 | }; |
| 143 | |
| 144 | static inline u64 btrfs_header_blocknr(struct btrfs_header *h) |
| 145 | { |
| 146 | return le64_to_cpu(h->blocknr); |
| 147 | } |
| 148 | |
| 149 | static inline void btrfs_set_header_blocknr(struct btrfs_header *h, u64 blocknr) |
| 150 | { |
| 151 | h->blocknr = cpu_to_le64(blocknr); |
| 152 | } |
| 153 | |
| 154 | static inline u64 btrfs_header_parentid(struct btrfs_header *h) |
| 155 | { |
| 156 | return le64_to_cpu(h->parentid); |
| 157 | } |
| 158 | |
| 159 | static inline void btrfs_set_header_parentid(struct btrfs_header *h, |
| 160 | u64 parentid) |
| 161 | { |
| 162 | h->parentid = cpu_to_le64(parentid); |
| 163 | } |
| 164 | |
| 165 | static inline u16 btrfs_header_nritems(struct btrfs_header *h) |
| 166 | { |
| 167 | return le16_to_cpu(h->nritems); |
| 168 | } |
| 169 | |
| 170 | static inline void btrfs_set_header_nritems(struct btrfs_header *h, u16 val) |
| 171 | { |
| 172 | h->nritems = cpu_to_le16(val); |
| 173 | } |
| 174 | |
| 175 | static inline u16 btrfs_header_flags(struct btrfs_header *h) |
| 176 | { |
| 177 | return le16_to_cpu(h->flags); |
| 178 | } |
| 179 | |
| 180 | static inline void btrfs_set_header_flags(struct btrfs_header *h, u16 val) |
| 181 | { |
| 182 | h->flags = cpu_to_le16(val); |
| 183 | } |
| 184 | |
| 185 | static inline int btrfs_header_level(struct btrfs_header *h) |
| 186 | { |
| 187 | return btrfs_header_flags(h) & (MAX_LEVEL - 1); |
| 188 | } |
| 189 | |
| 190 | static inline void btrfs_set_header_level(struct btrfs_header *h, int level) |
| 191 | { |
| 192 | u16 flags; |
| 193 | BUG_ON(level > MAX_LEVEL); |
| 194 | flags = btrfs_header_flags(h) & ~(MAX_LEVEL - 1); |
| 195 | btrfs_set_header_flags(h, flags | level); |
| 196 | } |
| 197 | |
| 198 | static inline int btrfs_is_leaf(struct node *n) |
| 199 | { |
| 200 | return (btrfs_header_level(&n->header) == 0); |
| 201 | } |
| 202 | |
| 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); |
| 215 | #endif |