fs/btrfs/ctree.h

   1 #ifndef __BTRFS__
   2 #define __BTRFS__
   3
   4 #include "list.h"
   5 #include "kerncompat.h"
   6
   7 #define BTRFS_MAGIC "_BtRfS_M"
   8 #define BTRFS_BLOCKSIZE 1024
   9
  10 #define BTRFS_ROOT_TREE_OBJECTID 1
  11 #define BTRFS_EXTENT_TREE_OBJECTID 2
  12 #define BTRFS_FS_TREE_OBJECTID 3
  13
  14 /*
  15  * the key defines the order in the tree, and so it also defines (optimal)
  16  * block layout.  objectid corresonds to the inode number.  The flags
  17  * tells us things about the object, and is a kind of stream selector.
  18  * so for a given inode, keys with flags of 1 might refer to the inode
  19  * data, flags of 2 may point to file data in the btree and flags == 3
  20  * may point to extents.
  21  *
  22  * offset is the starting byte offset for this key in the stream.
  23  *
  24  * btrfs_disk_key is in disk byte order.  struct btrfs_key is always
  25  * in cpu native order.  Otherwise they are identical and their sizes
  26  * should be the same (ie both packed)
  27  */
  28 struct btrfs_disk_key {
  29         __le64 objectid;
  30         __le32 flags;
  31         __le64 offset;
  32 } __attribute__ ((__packed__));
  33
  34 struct btrfs_key {
  35         u64 objectid;
  36         u32 flags;
  37         u64 offset;
  38 } __attribute__ ((__packed__));
  39
  40 /*
  41  * every tree block (leaf or node) starts with this header.
  42  */
  43 struct btrfs_header {
  44         u8 fsid[16]; /* FS specific uuid */
  45         __le64 blocknr; /* which block this node is supposed to live in */
  46         __le64 parentid; /* objectid of the tree root */
  47         __le32 csum;
  48         __le32 ham;
  49         __le16 nritems;
  50         __le16 flags;
  51         /* generation flags to be added */
  52 } __attribute__ ((__packed__));
  53
  54 #define BTRFS_MAX_LEVEL 8
  55 #define NODEPTRS_PER_BLOCK ((BTRFS_BLOCKSIZE - sizeof(struct btrfs_header)) / \
  56                             (sizeof(struct btrfs_disk_key) + sizeof(u64)))
  57
  58 struct btrfs_buffer;
  59
  60 struct btrfs_root_item {
  61         __le64 blocknr;
  62         __le32 flags;
  63         __le64 block_limit;
  64         __le64 blocks_used;
  65         __le32 refs;
  66 };
  67
  68 /*
  69  * in ram representation of the tree.  extent_root is used for all allocations
  70  * and for the extent tree extent_root root.  current_insert is used
  71  * only for the extent tree.
  72  */
  73 struct btrfs_root {
  74         struct btrfs_buffer *node;
  75         struct btrfs_buffer *commit_root;
  76         struct btrfs_root *extent_root;
  77         struct btrfs_root *tree_root;
  78         struct btrfs_key current_insert;
  79         struct btrfs_key last_insert;
  80         int fp;
  81         struct radix_tree_root cache_radix;
  82         struct radix_tree_root pinned_radix;
  83         struct list_head trans;
  84         struct list_head cache;
  85         int cache_size;
  86         int ref_cows;
  87         struct btrfs_root_item root_item;
  88         struct btrfs_key root_key;
  89 };
  90
  91 /*
  92  * the super block basically lists the main trees of the FS
  93  * it currently lacks any block count etc etc
  94  */
  95 struct btrfs_super_block {
  96         u8 fsid[16];    /* FS specific uuid */
  97         __le64 blocknr; /* this block number */
  98         __le32 csum;
  99         __le64 magic;
 100         __le16 blocksize;
 101         __le64 generation;
 102         __le64 root;
 103         __le64 total_blocks;
 104         __le64 blocks_used;
 105 } __attribute__ ((__packed__));
 106
 107 /*
 108  * A leaf is full of items.  The exact type of item is defined by
 109  * the key flags parameter.  offset and size tell us where to find
 110  * the item in the leaf (relative to the start of the data area)
 111  */
 112 struct btrfs_item {
 113         struct btrfs_disk_key key;
 114         __le16 offset;
 115         __le16 size;
 116 } __attribute__ ((__packed__));
 117
 118 /*
 119  * leaves have an item area and a data area:
 120  * [item0, item1....itemN] [free space] [dataN...data1, data0]
 121  *
 122  * The data is separate from the items to get the keys closer together
 123  * during searches.
 124  */
 125 #define LEAF_DATA_SIZE (BTRFS_BLOCKSIZE - sizeof(struct btrfs_header))
 126 struct btrfs_leaf {
 127         struct btrfs_header header;
 128         union {
 129                 struct btrfs_item items[LEAF_DATA_SIZE/
 130                                         sizeof(struct btrfs_item)];
 131                 u8 data[BTRFS_BLOCKSIZE - sizeof(struct btrfs_header)];
 132         };
 133 } __attribute__ ((__packed__));
 134
 135 /*
 136  * all non-leaf blocks are nodes, they hold only keys and pointers to
 137  * other blocks
 138  */
 139 struct btrfs_node {
 140         struct btrfs_header header;
 141         struct btrfs_disk_key keys[NODEPTRS_PER_BLOCK];
 142         __le64 blockptrs[NODEPTRS_PER_BLOCK];
 143 } __attribute__ ((__packed__));
 144
 145 /*
 146  * items in the extent btree are used to record the objectid of the
 147  * owner of the block and the number of references
 148  */
 149 struct btrfs_extent_item {
 150         __le32 refs;
 151         __le64 owner;
 152 } __attribute__ ((__packed__));
 153
 154 /*
 155  * btrfs_paths remember the path taken from the root down to the leaf.
 156  * level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
 157  * to any other levels that are present.
 158  *
 159  * The slots array records the index of the item or block pointer
 160  * used while walking the tree.
 161  */
 162 struct btrfs_path {
 163         struct btrfs_buffer *nodes[BTRFS_MAX_LEVEL];
 164         int slots[BTRFS_MAX_LEVEL];
 165 };
 166
 167 static inline u64 btrfs_extent_owner(struct btrfs_extent_item *ei)
 168 {
 169         return le64_to_cpu(ei->owner);
 170 }
 171
 172 static inline void btrfs_set_extent_owner(struct btrfs_extent_item *ei, u64 val)
 173 {
 174         ei->owner = cpu_to_le64(val);
 175 }
 176
 177 static inline u32 btrfs_extent_refs(struct btrfs_extent_item *ei)
 178 {
 179         return le32_to_cpu(ei->refs);
 180 }
 181
 182 static inline void btrfs_set_extent_refs(struct btrfs_extent_item *ei, u32 val)
 183 {
 184         ei->refs = cpu_to_le32(val);
 185 }
 186
 187 static inline u64 btrfs_node_blockptr(struct btrfs_node *n, int nr)
 188 {
 189         return le64_to_cpu(n->blockptrs[nr]);
 190 }
 191
 192 static inline void btrfs_set_node_blockptr(struct btrfs_node *n, int nr,
 193                                            u64 val)
 194 {
 195         n->blockptrs[nr] = cpu_to_le64(val);
 196 }
 197
 198 static inline u16 btrfs_item_offset(struct btrfs_item *item)
 199 {
 200         return le16_to_cpu(item->offset);
 201 }
 202
 203 static inline void btrfs_set_item_offset(struct btrfs_item *item, u16 val)
 204 {
 205         item->offset = cpu_to_le16(val);
 206 }
 207
 208 static inline u16 btrfs_item_end(struct btrfs_item *item)
 209 {
 210         return le16_to_cpu(item->offset) + le16_to_cpu(item->size);
 211 }
 212
 213 static inline u16 btrfs_item_size(struct btrfs_item *item)
 214 {
 215         return le16_to_cpu(item->size);
 216 }
 217
 218 static inline void btrfs_set_item_size(struct btrfs_item *item, u16 val)
 219 {
 220         item->size = cpu_to_le16(val);
 221 }
 222
 223 static inline void btrfs_disk_key_to_cpu(struct btrfs_key *cpu,
 224                                          struct btrfs_disk_key *disk)
 225 {
 226         cpu->offset = le64_to_cpu(disk->offset);
 227         cpu->flags = le32_to_cpu(disk->flags);
 228         cpu->objectid = le64_to_cpu(disk->objectid);
 229 }
 230
 231 static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk,
 232                                          struct btrfs_key *cpu)
 233 {
 234         disk->offset = cpu_to_le64(cpu->offset);
 235         disk->flags = cpu_to_le32(cpu->flags);
 236         disk->objectid = cpu_to_le64(cpu->objectid);
 237 }
 238
 239 static inline u64 btrfs_key_objectid(struct btrfs_disk_key *disk)
 240 {
 241         return le64_to_cpu(disk->objectid);
 242 }
 243
 244 static inline void btrfs_set_key_objectid(struct btrfs_disk_key *disk,
 245                                           u64 val)
 246 {
 247         disk->objectid = cpu_to_le64(val);
 248 }
 249
 250 static inline u64 btrfs_key_offset(struct btrfs_disk_key *disk)
 251 {
 252         return le64_to_cpu(disk->offset);
 253 }
 254
 255 static inline void btrfs_set_key_offset(struct btrfs_disk_key *disk,
 256                                           u64 val)
 257 {
 258         disk->offset = cpu_to_le64(val);
 259 }
 260
 261 static inline u32 btrfs_key_flags(struct btrfs_disk_key *disk)
 262 {
 263         return le32_to_cpu(disk->flags);
 264 }
 265
 266 static inline void btrfs_set_key_flags(struct btrfs_disk_key *disk,
 267                                           u32 val)
 268 {
 269         disk->flags = cpu_to_le32(val);
 270 }
 271
 272 static inline u64 btrfs_header_blocknr(struct btrfs_header *h)
 273 {
 274         return le64_to_cpu(h->blocknr);
 275 }
 276
 277 static inline void btrfs_set_header_blocknr(struct btrfs_header *h, u64 blocknr)
 278 {
 279         h->blocknr = cpu_to_le64(blocknr);
 280 }
 281
 282 static inline u64 btrfs_header_parentid(struct btrfs_header *h)
 283 {
 284         return le64_to_cpu(h->parentid);
 285 }
 286
 287 static inline void btrfs_set_header_parentid(struct btrfs_header *h,
 288                                              u64 parentid)
 289 {
 290         h->parentid = cpu_to_le64(parentid);
 291 }
 292
 293 static inline u16 btrfs_header_nritems(struct btrfs_header *h)
 294 {
 295         return le16_to_cpu(h->nritems);
 296 }
 297
 298 static inline void btrfs_set_header_nritems(struct btrfs_header *h, u16 val)
 299 {
 300         h->nritems = cpu_to_le16(val);
 301 }
 302
 303 static inline u16 btrfs_header_flags(struct btrfs_header *h)
 304 {
 305         return le16_to_cpu(h->flags);
 306 }
 307
 308 static inline void btrfs_set_header_flags(struct btrfs_header *h, u16 val)
 309 {
 310         h->flags = cpu_to_le16(val);
 311 }
 312
 313 static inline int btrfs_header_level(struct btrfs_header *h)
 314 {
 315         return btrfs_header_flags(h) & (BTRFS_MAX_LEVEL - 1);
 316 }
 317
 318 static inline void btrfs_set_header_level(struct btrfs_header *h, int level)
 319 {
 320         u16 flags;
 321         BUG_ON(level > BTRFS_MAX_LEVEL);
 322         flags = btrfs_header_flags(h) & ~(BTRFS_MAX_LEVEL - 1);
 323         btrfs_set_header_flags(h, flags | level);
 324 }
 325
 326 static inline int btrfs_is_leaf(struct btrfs_node *n)
 327 {
 328         return (btrfs_header_level(&n->header) == 0);
 329 }
 330
 331 static inline u64 btrfs_root_blocknr(struct btrfs_root_item *item)
 332 {
 333         return le64_to_cpu(item->blocknr);
 334 }
 335
 336 static inline void btrfs_set_root_blocknr(struct btrfs_root_item *item, u64 val)
 337 {
 338         item->blocknr = cpu_to_le64(val);
 339 }
 340
 341 static inline u32 btrfs_root_refs(struct btrfs_root_item *item)
 342 {
 343         return le32_to_cpu(item->refs);
 344 }
 345
 346 static inline void btrfs_set_root_refs(struct btrfs_root_item *item, u32 val)
 347 {
 348         item->refs = cpu_to_le32(val);
 349 }
 350
 351 static inline u64 btrfs_super_blocknr(struct btrfs_super_block *s)
 352 {
 353         return le64_to_cpu(s->blocknr);
 354 }
 355
 356 static inline void btrfs_set_super_blocknr(struct btrfs_super_block *s, u64 val)
 357 {
 358         s->blocknr = cpu_to_le64(val);
 359 }
 360
 361 static inline u64 btrfs_super_root(struct btrfs_super_block *s)
 362 {
 363         return le64_to_cpu(s->root);
 364 }
 365
 366 static inline void btrfs_set_super_root(struct btrfs_super_block *s, u64 val)
 367 {
 368         s->root = cpu_to_le64(val);
 369 }
 370
 371 static inline u64 btrfs_super_total_blocks(struct btrfs_super_block *s)
 372 {
 373         return le64_to_cpu(s->total_blocks);
 374 }
 375
 376 static inline void btrfs_set_super_total_blocks(struct btrfs_super_block *s,
 377                                                 u64 val)
 378 {
 379         s->total_blocks = cpu_to_le64(val);
 380 }
 381
 382 static inline u64 btrfs_super_blocks_used(struct btrfs_super_block *s)
 383 {
 384         return le64_to_cpu(s->blocks_used);
 385 }
 386
 387 static inline void btrfs_set_super_blocks_used(struct btrfs_super_block *s,
 388                                                 u64 val)
 389 {
 390         s->blocks_used = cpu_to_le64(val);
 391 }
 392
 393 static inline u16 btrfs_super_blocksize(struct btrfs_super_block *s)
 394 {
 395         return le16_to_cpu(s->blocksize);
 396 }
 397
 398 static inline void btrfs_set_super_blocksize(struct btrfs_super_block *s,
 399                                                 u16 val)
 400 {
 401         s->blocksize = cpu_to_le16(val);
 402 }
 403
 404 struct btrfs_buffer *btrfs_alloc_free_block(struct btrfs_root *root);
 405 int btrfs_inc_ref(struct btrfs_root *root, struct btrfs_buffer *buf);
 406 int btrfs_free_extent(struct btrfs_root *root, u64 blocknr, u64 num_blocks);
 407 int btrfs_search_slot(struct btrfs_root *root, struct btrfs_key *key,
 408                 struct btrfs_path *p, int ins_len, int cow);
 409 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p);
 410 void btrfs_init_path(struct btrfs_path *p);
 411 int btrfs_del_item(struct btrfs_root *root, struct btrfs_path *path);
 412 int btrfs_insert_item(struct btrfs_root *root, struct btrfs_key *key,
 413                 void *data, int data_size);
 414 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
 415 int btrfs_leaf_free_space(struct btrfs_leaf *leaf);
 416 int btrfs_drop_snapshot(struct btrfs_root *root, struct btrfs_buffer *snap);
 417 int btrfs_finish_extent_commit(struct btrfs_root *root);
 418 int btrfs_del_root(struct btrfs_root *root, struct btrfs_key *key);
 419 int btrfs_insert_root(struct btrfs_root *root, struct btrfs_key *key,
 420                       struct btrfs_root_item *item);
 421 int btrfs_update_root(struct btrfs_root *root, struct btrfs_key *key,
 422                       struct btrfs_root_item *item);
 423 int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
 424                         struct btrfs_root_item *item, struct btrfs_key *key);
 425 #endif