5 #include "kerncompat.h"
7 #define CTREE_BLOCKSIZE 1024
10 * the key defines the order in the tree, and so it also defines (optimal)
11 * block layout. objectid corresonds to the inode number. The flags
12 * tells us things about the object, and is a kind of stream selector.
13 * so for a given inode, keys with flags of 1 might refer to the inode
14 * data, flags of 2 may point to file data in the btree and flags == 3
15 * may point to extents.
17 * offset is the starting byte offset for this key in the stream.
19 * btrfs_disk_key is in disk byte order. struct btrfs_key is always
20 * in cpu native order. Otherwise they are identical and their sizes
21 * should be the same (ie both packed)
23 struct btrfs_disk_key {
27 } __attribute__ ((__packed__));
33 } __attribute__ ((__packed__));
36 * every tree block (leaf or node) starts with this header.
39 __le64 fsid[2]; /* FS specific uuid */
40 __le64 blocknr; /* which block this node is supposed to live in */
41 __le64 parentid; /* objectid of the tree root */
46 /* generation flags to be added */
47 } __attribute__ ((__packed__));
50 #define NODEPTRS_PER_BLOCK ((CTREE_BLOCKSIZE - sizeof(struct btrfs_header)) / \
51 (sizeof(struct btrfs_disk_key) + sizeof(u64)))
56 * in ram representation of the tree. extent_root is used for all allocations
57 * and for the extent tree extent_root root. current_insert is used
58 * only for the extent tree.
61 struct tree_buffer *node;
62 struct tree_buffer *commit_root;
63 struct ctree_root *extent_root;
64 struct btrfs_key current_insert;
65 struct btrfs_key last_insert;
67 struct radix_tree_root cache_radix;
68 struct radix_tree_root pinned_radix;
69 struct list_head trans;
70 struct list_head cache;
75 * describes a tree on disk
77 struct ctree_root_info {
78 u64 fsid[2]; /* FS specific uuid */
79 u64 blocknr; /* blocknr of this block */
80 u64 objectid; /* inode number of this root */
81 u64 tree_root; /* the tree root block */
84 u64 snapuuid[2]; /* root specific uuid */
85 } __attribute__ ((__packed__));
88 * the super block basically lists the main trees of the FS
89 * it currently lacks any block count etc etc
91 struct ctree_super_block {
92 struct ctree_root_info root_info;
93 struct ctree_root_info extent_info;
94 } __attribute__ ((__packed__));
97 * A leaf is full of items. The exact type of item is defined by
98 * the key flags parameter. offset and size tell us where to find
99 * the item in the leaf (relative to the start of the data area)
102 struct btrfs_disk_key key;
105 } __attribute__ ((__packed__));
108 * leaves have an item area and a data area:
109 * [item0, item1....itemN] [free space] [dataN...data1, data0]
111 * The data is separate from the items to get the keys closer together
114 #define LEAF_DATA_SIZE (CTREE_BLOCKSIZE - sizeof(struct btrfs_header))
116 struct btrfs_header header;
118 struct item items[LEAF_DATA_SIZE/sizeof(struct item)];
119 u8 data[CTREE_BLOCKSIZE-sizeof(struct btrfs_header)];
121 } __attribute__ ((__packed__));
124 * all non-leaf blocks are nodes, they hold only keys and pointers to
128 struct btrfs_header header;
129 struct btrfs_disk_key keys[NODEPTRS_PER_BLOCK];
130 u64 blockptrs[NODEPTRS_PER_BLOCK];
131 } __attribute__ ((__packed__));
134 * items in the extent btree are used to record the objectid of the
135 * owner of the block and the number of references
140 } __attribute__ ((__packed__));
143 * ctree_paths remember the path taken from the root down to the leaf.
144 * level 0 is always the leaf, and nodes[1...MAX_LEVEL] will point
145 * to any other levels that are present.
147 * The slots array records the index of the item or block pointer
148 * used while walking the tree.
151 struct tree_buffer *nodes[MAX_LEVEL];
152 int slots[MAX_LEVEL];
155 static inline void btrfs_disk_key_to_cpu(struct btrfs_key *cpu,
156 struct btrfs_disk_key *disk)
158 cpu->offset = le64_to_cpu(disk->offset);
159 cpu->flags = le32_to_cpu(disk->flags);
160 cpu->objectid = le64_to_cpu(disk->objectid);
163 static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk,
164 struct btrfs_key *cpu)
166 disk->offset = cpu_to_le64(cpu->offset);
167 disk->flags = cpu_to_le32(cpu->flags);
168 disk->objectid = cpu_to_le64(cpu->objectid);
171 static inline u64 btrfs_key_objectid(struct btrfs_disk_key *disk)
173 return le64_to_cpu(disk->objectid);
176 static inline void btrfs_set_key_objectid(struct btrfs_disk_key *disk,
179 disk->objectid = cpu_to_le64(val);
182 static inline u64 btrfs_key_offset(struct btrfs_disk_key *disk)
184 return le64_to_cpu(disk->offset);
187 static inline void btrfs_set_key_offset(struct btrfs_disk_key *disk,
190 disk->offset = cpu_to_le64(val);
193 static inline u32 btrfs_key_flags(struct btrfs_disk_key *disk)
195 return le32_to_cpu(disk->flags);
198 static inline void btrfs_set_key_flags(struct btrfs_disk_key *disk,
201 disk->flags = cpu_to_le32(val);
204 static inline u64 btrfs_header_blocknr(struct btrfs_header *h)
206 return le64_to_cpu(h->blocknr);
209 static inline void btrfs_set_header_blocknr(struct btrfs_header *h, u64 blocknr)
211 h->blocknr = cpu_to_le64(blocknr);
214 static inline u64 btrfs_header_parentid(struct btrfs_header *h)
216 return le64_to_cpu(h->parentid);
219 static inline void btrfs_set_header_parentid(struct btrfs_header *h,
222 h->parentid = cpu_to_le64(parentid);
225 static inline u16 btrfs_header_nritems(struct btrfs_header *h)
227 return le16_to_cpu(h->nritems);
230 static inline void btrfs_set_header_nritems(struct btrfs_header *h, u16 val)
232 h->nritems = cpu_to_le16(val);
235 static inline u16 btrfs_header_flags(struct btrfs_header *h)
237 return le16_to_cpu(h->flags);
240 static inline void btrfs_set_header_flags(struct btrfs_header *h, u16 val)
242 h->flags = cpu_to_le16(val);
245 static inline int btrfs_header_level(struct btrfs_header *h)
247 return btrfs_header_flags(h) & (MAX_LEVEL - 1);
250 static inline void btrfs_set_header_level(struct btrfs_header *h, int level)
253 BUG_ON(level > MAX_LEVEL);
254 flags = btrfs_header_flags(h) & ~(MAX_LEVEL - 1);
255 btrfs_set_header_flags(h, flags | level);
258 static inline int btrfs_is_leaf(struct node *n)
260 return (btrfs_header_level(&n->header) == 0);
263 struct tree_buffer *alloc_free_block(struct ctree_root *root);
264 int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf);
265 int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks);
266 int search_slot(struct ctree_root *root, struct btrfs_key *key,
267 struct ctree_path *p, int ins_len, int cow);
268 void release_path(struct ctree_root *root, struct ctree_path *p);
269 void init_path(struct ctree_path *p);
270 int del_item(struct ctree_root *root, struct ctree_path *path);
271 int insert_item(struct ctree_root *root, struct btrfs_key *key,
272 void *data, int data_size);
273 int next_leaf(struct ctree_root *root, struct ctree_path *path);
274 int leaf_free_space(struct leaf *leaf);
275 int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap);
276 int btrfs_finish_extent_commit(struct ctree_root *root);