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