1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Copyright (C) 2008 Oracle. All rights reserved. 4 */ 5 6 #ifndef BTRFS_DELAYED_REF_H 7 #define BTRFS_DELAYED_REF_H 8 9 #include <linux/refcount.h> 10 11 /* these are the possible values of struct btrfs_delayed_ref_node->action */ 12 #define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */ 13 #define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */ 14 #define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */ 15 #define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */ 16 17 struct btrfs_delayed_ref_node { 18 struct rb_node ref_node; 19 /* 20 * If action is BTRFS_ADD_DELAYED_REF, also link this node to 21 * ref_head->ref_add_list, then we do not need to iterate the 22 * whole ref_head->ref_list to find BTRFS_ADD_DELAYED_REF nodes. 23 */ 24 struct list_head add_list; 25 26 /* the starting bytenr of the extent */ 27 u64 bytenr; 28 29 /* the size of the extent */ 30 u64 num_bytes; 31 32 /* seq number to keep track of insertion order */ 33 u64 seq; 34 35 /* ref count on this data structure */ 36 refcount_t refs; 37 38 /* 39 * how many refs is this entry adding or deleting. For 40 * head refs, this may be a negative number because it is keeping 41 * track of the total mods done to the reference count. 42 * For individual refs, this will always be a positive number 43 * 44 * It may be more than one, since it is possible for a single 45 * parent to have more than one ref on an extent 46 */ 47 int ref_mod; 48 49 unsigned int action:8; 50 unsigned int type:8; 51 }; 52 53 struct btrfs_delayed_extent_op { 54 struct btrfs_disk_key key; 55 u8 level; 56 bool update_key; 57 bool update_flags; 58 u64 flags_to_set; 59 }; 60 61 /* 62 * the head refs are used to hold a lock on a given extent, which allows us 63 * to make sure that only one process is running the delayed refs 64 * at a time for a single extent. They also store the sum of all the 65 * reference count modifications we've queued up. 66 */ 67 struct btrfs_delayed_ref_head { 68 u64 bytenr; 69 u64 num_bytes; 70 /* 71 * For insertion into struct btrfs_delayed_ref_root::href_root. 72 * Keep it in the same cache line as 'bytenr' for more efficient 73 * searches in the rbtree. 74 */ 75 struct rb_node href_node; 76 /* 77 * the mutex is held while running the refs, and it is also 78 * held when checking the sum of reference modifications. 79 */ 80 struct mutex mutex; 81 82 refcount_t refs; 83 84 /* Protects 'ref_tree' and 'ref_add_list'. */ 85 spinlock_t lock; 86 struct rb_root_cached ref_tree; 87 /* accumulate add BTRFS_ADD_DELAYED_REF nodes to this ref_add_list. */ 88 struct list_head ref_add_list; 89 90 struct btrfs_delayed_extent_op *extent_op; 91 92 /* 93 * This is used to track the final ref_mod from all the refs associated 94 * with this head ref, this is not adjusted as delayed refs are run, 95 * this is meant to track if we need to do the csum accounting or not. 96 */ 97 int total_ref_mod; 98 99 /* 100 * This is the current outstanding mod references for this bytenr. This 101 * is used with lookup_extent_info to get an accurate reference count 102 * for a bytenr, so it is adjusted as delayed refs are run so that any 103 * on disk reference count + ref_mod is accurate. 104 */ 105 int ref_mod; 106 107 /* 108 * when a new extent is allocated, it is just reserved in memory 109 * The actual extent isn't inserted into the extent allocation tree 110 * until the delayed ref is processed. must_insert_reserved is 111 * used to flag a delayed ref so the accounting can be updated 112 * when a full insert is done. 113 * 114 * It is possible the extent will be freed before it is ever 115 * inserted into the extent allocation tree. In this case 116 * we need to update the in ram accounting to properly reflect 117 * the free has happened. 118 */ 119 bool must_insert_reserved; 120 bool is_data; 121 bool is_system; 122 bool processing; 123 }; 124 125 struct btrfs_delayed_tree_ref { 126 struct btrfs_delayed_ref_node node; 127 u64 root; 128 u64 parent; 129 int level; 130 }; 131 132 struct btrfs_delayed_data_ref { 133 struct btrfs_delayed_ref_node node; 134 u64 root; 135 u64 parent; 136 u64 objectid; 137 u64 offset; 138 }; 139 140 enum btrfs_delayed_ref_flags { 141 /* Indicate that we are flushing delayed refs for the commit */ 142 BTRFS_DELAYED_REFS_FLUSHING, 143 }; 144 145 struct btrfs_delayed_ref_root { 146 /* head ref rbtree */ 147 struct rb_root_cached href_root; 148 149 /* dirty extent records */ 150 struct rb_root dirty_extent_root; 151 152 /* this spin lock protects the rbtree and the entries inside */ 153 spinlock_t lock; 154 155 /* how many delayed ref updates we've queued, used by the 156 * throttling code 157 */ 158 atomic_t num_entries; 159 160 /* total number of head nodes in tree */ 161 unsigned long num_heads; 162 163 /* total number of head nodes ready for processing */ 164 unsigned long num_heads_ready; 165 166 u64 pending_csums; 167 168 unsigned long flags; 169 170 u64 run_delayed_start; 171 172 /* 173 * To make qgroup to skip given root. 174 * This is for snapshot, as btrfs_qgroup_inherit() will manually 175 * modify counters for snapshot and its source, so we should skip 176 * the snapshot in new_root/old_roots or it will get calculated twice 177 */ 178 u64 qgroup_to_skip; 179 }; 180 181 enum btrfs_ref_type { 182 BTRFS_REF_NOT_SET, 183 BTRFS_REF_DATA, 184 BTRFS_REF_METADATA, 185 BTRFS_REF_LAST, 186 }; 187 188 struct btrfs_data_ref { 189 /* For EXTENT_DATA_REF */ 190 191 /* Original root this data extent belongs to */ 192 u64 owning_root; 193 194 /* Inode which refers to this data extent */ 195 u64 ino; 196 197 /* 198 * file_offset - extent_offset 199 * 200 * file_offset is the key.offset of the EXTENT_DATA key. 201 * extent_offset is btrfs_file_extent_offset() of the EXTENT_DATA data. 202 */ 203 u64 offset; 204 }; 205 206 struct btrfs_tree_ref { 207 /* 208 * Level of this tree block 209 * 210 * Shared for skinny (TREE_BLOCK_REF) and normal tree ref. 211 */ 212 int level; 213 214 /* 215 * Root which owns this tree block. 216 * 217 * For TREE_BLOCK_REF (skinny metadata, either inline or keyed) 218 */ 219 u64 owning_root; 220 221 /* For non-skinny metadata, no special member needed */ 222 }; 223 224 struct btrfs_ref { 225 enum btrfs_ref_type type; 226 int action; 227 228 /* 229 * Whether this extent should go through qgroup record. 230 * 231 * Normally false, but for certain cases like delayed subtree scan, 232 * setting this flag can hugely reduce qgroup overhead. 233 */ 234 bool skip_qgroup; 235 236 #ifdef CONFIG_BTRFS_FS_REF_VERIFY 237 /* Through which root is this modification. */ 238 u64 real_root; 239 #endif 240 u64 bytenr; 241 u64 len; 242 243 /* Bytenr of the parent tree block */ 244 u64 parent; 245 union { 246 struct btrfs_data_ref data_ref; 247 struct btrfs_tree_ref tree_ref; 248 }; 249 }; 250 251 extern struct kmem_cache *btrfs_delayed_ref_head_cachep; 252 extern struct kmem_cache *btrfs_delayed_tree_ref_cachep; 253 extern struct kmem_cache *btrfs_delayed_data_ref_cachep; 254 extern struct kmem_cache *btrfs_delayed_extent_op_cachep; 255 256 int __init btrfs_delayed_ref_init(void); 257 void __cold btrfs_delayed_ref_exit(void); 258 259 static inline u64 btrfs_calc_delayed_ref_bytes(const struct btrfs_fs_info *fs_info, 260 int num_delayed_refs) 261 { 262 u64 num_bytes; 263 264 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_delayed_refs); 265 266 /* 267 * We have to check the mount option here because we could be enabling 268 * the free space tree for the first time and don't have the compat_ro 269 * option set yet. 270 * 271 * We need extra reservations if we have the free space tree because 272 * we'll have to modify that tree as well. 273 */ 274 if (btrfs_test_opt(fs_info, FREE_SPACE_TREE)) 275 num_bytes *= 2; 276 277 return num_bytes; 278 } 279 280 static inline void btrfs_init_generic_ref(struct btrfs_ref *generic_ref, 281 int action, u64 bytenr, u64 len, u64 parent) 282 { 283 generic_ref->action = action; 284 generic_ref->bytenr = bytenr; 285 generic_ref->len = len; 286 generic_ref->parent = parent; 287 } 288 289 static inline void btrfs_init_tree_ref(struct btrfs_ref *generic_ref, 290 int level, u64 root, u64 mod_root, bool skip_qgroup) 291 { 292 #ifdef CONFIG_BTRFS_FS_REF_VERIFY 293 /* If @real_root not set, use @root as fallback */ 294 generic_ref->real_root = mod_root ?: root; 295 #endif 296 generic_ref->tree_ref.level = level; 297 generic_ref->tree_ref.owning_root = root; 298 generic_ref->type = BTRFS_REF_METADATA; 299 if (skip_qgroup || !(is_fstree(root) && 300 (!mod_root || is_fstree(mod_root)))) 301 generic_ref->skip_qgroup = true; 302 else 303 generic_ref->skip_qgroup = false; 304 305 } 306 307 static inline void btrfs_init_data_ref(struct btrfs_ref *generic_ref, 308 u64 ref_root, u64 ino, u64 offset, u64 mod_root, 309 bool skip_qgroup) 310 { 311 #ifdef CONFIG_BTRFS_FS_REF_VERIFY 312 /* If @real_root not set, use @root as fallback */ 313 generic_ref->real_root = mod_root ?: ref_root; 314 #endif 315 generic_ref->data_ref.owning_root = ref_root; 316 generic_ref->data_ref.ino = ino; 317 generic_ref->data_ref.offset = offset; 318 generic_ref->type = BTRFS_REF_DATA; 319 if (skip_qgroup || !(is_fstree(ref_root) && 320 (!mod_root || is_fstree(mod_root)))) 321 generic_ref->skip_qgroup = true; 322 else 323 generic_ref->skip_qgroup = false; 324 } 325 326 static inline struct btrfs_delayed_extent_op * 327 btrfs_alloc_delayed_extent_op(void) 328 { 329 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS); 330 } 331 332 static inline void 333 btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op) 334 { 335 if (op) 336 kmem_cache_free(btrfs_delayed_extent_op_cachep, op); 337 } 338 339 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) 340 { 341 WARN_ON(refcount_read(&ref->refs) == 0); 342 if (refcount_dec_and_test(&ref->refs)) { 343 WARN_ON(!RB_EMPTY_NODE(&ref->ref_node)); 344 switch (ref->type) { 345 case BTRFS_TREE_BLOCK_REF_KEY: 346 case BTRFS_SHARED_BLOCK_REF_KEY: 347 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref); 348 break; 349 case BTRFS_EXTENT_DATA_REF_KEY: 350 case BTRFS_SHARED_DATA_REF_KEY: 351 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref); 352 break; 353 default: 354 BUG(); 355 } 356 } 357 } 358 359 static inline u64 btrfs_ref_head_to_space_flags( 360 struct btrfs_delayed_ref_head *head_ref) 361 { 362 if (head_ref->is_data) 363 return BTRFS_BLOCK_GROUP_DATA; 364 else if (head_ref->is_system) 365 return BTRFS_BLOCK_GROUP_SYSTEM; 366 return BTRFS_BLOCK_GROUP_METADATA; 367 } 368 369 static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *head) 370 { 371 if (refcount_dec_and_test(&head->refs)) 372 kmem_cache_free(btrfs_delayed_ref_head_cachep, head); 373 } 374 375 int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans, 376 struct btrfs_ref *generic_ref, 377 struct btrfs_delayed_extent_op *extent_op); 378 int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans, 379 struct btrfs_ref *generic_ref, 380 u64 reserved); 381 int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans, 382 u64 bytenr, u64 num_bytes, 383 struct btrfs_delayed_extent_op *extent_op); 384 void btrfs_merge_delayed_refs(struct btrfs_fs_info *fs_info, 385 struct btrfs_delayed_ref_root *delayed_refs, 386 struct btrfs_delayed_ref_head *head); 387 388 struct btrfs_delayed_ref_head * 389 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, 390 u64 bytenr); 391 int btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs, 392 struct btrfs_delayed_ref_head *head); 393 static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head) 394 { 395 mutex_unlock(&head->mutex); 396 } 397 void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs, 398 struct btrfs_delayed_ref_head *head); 399 400 struct btrfs_delayed_ref_head *btrfs_select_ref_head( 401 struct btrfs_delayed_ref_root *delayed_refs); 402 403 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq); 404 405 void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr); 406 void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans); 407 int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info, 408 enum btrfs_reserve_flush_enum flush); 409 void btrfs_migrate_to_delayed_refs_rsv(struct btrfs_fs_info *fs_info, 410 struct btrfs_block_rsv *src, 411 u64 num_bytes); 412 bool btrfs_check_space_for_delayed_refs(struct btrfs_fs_info *fs_info); 413 414 /* 415 * helper functions to cast a node into its container 416 */ 417 static inline struct btrfs_delayed_tree_ref * 418 btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node) 419 { 420 return container_of(node, struct btrfs_delayed_tree_ref, node); 421 } 422 423 static inline struct btrfs_delayed_data_ref * 424 btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node) 425 { 426 return container_of(node, struct btrfs_delayed_data_ref, node); 427 } 428 429 #endif 430