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