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 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 * For qgroup reserved space freeing. 107 * 108 * ref_root and reserved will be recorded after 109 * BTRFS_ADD_DELAYED_EXTENT is called. 110 * And will be used to free reserved qgroup space at 111 * run_delayed_refs() time. 112 */ 113 u64 qgroup_ref_root; 114 u64 qgroup_reserved; 115 116 /* 117 * when a new extent is allocated, it is just reserved in memory 118 * The actual extent isn't inserted into the extent allocation tree 119 * until the delayed ref is processed. must_insert_reserved is 120 * used to flag a delayed ref so the accounting can be updated 121 * when a full insert is done. 122 * 123 * It is possible the extent will be freed before it is ever 124 * inserted into the extent allocation tree. In this case 125 * we need to update the in ram accounting to properly reflect 126 * the free has happened. 127 */ 128 unsigned int must_insert_reserved:1; 129 unsigned int is_data:1; 130 unsigned int is_system:1; 131 unsigned int processing:1; 132 }; 133 134 struct btrfs_delayed_tree_ref { 135 struct btrfs_delayed_ref_node node; 136 u64 root; 137 u64 parent; 138 int level; 139 }; 140 141 struct btrfs_delayed_data_ref { 142 struct btrfs_delayed_ref_node node; 143 u64 root; 144 u64 parent; 145 u64 objectid; 146 u64 offset; 147 }; 148 149 struct btrfs_delayed_ref_root { 150 /* head ref rbtree */ 151 struct rb_root href_root; 152 153 /* dirty extent records */ 154 struct rb_root dirty_extent_root; 155 156 /* this spin lock protects the rbtree and the entries inside */ 157 spinlock_t lock; 158 159 /* how many delayed ref updates we've queued, used by the 160 * throttling code 161 */ 162 atomic_t num_entries; 163 164 /* total number of head nodes in tree */ 165 unsigned long num_heads; 166 167 /* total number of head nodes ready for processing */ 168 unsigned long num_heads_ready; 169 170 u64 pending_csums; 171 172 /* 173 * set when the tree is flushing before a transaction commit, 174 * used by the throttling code to decide if new updates need 175 * to be run right away 176 */ 177 int flushing; 178 179 u64 run_delayed_start; 180 181 /* 182 * To make qgroup to skip given root. 183 * This is for snapshot, as btrfs_qgroup_inherit() will manually 184 * modify counters for snapshot and its source, so we should skip 185 * the snapshot in new_root/old_roots or it will get calculated twice 186 */ 187 u64 qgroup_to_skip; 188 }; 189 190 extern struct kmem_cache *btrfs_delayed_ref_head_cachep; 191 extern struct kmem_cache *btrfs_delayed_tree_ref_cachep; 192 extern struct kmem_cache *btrfs_delayed_data_ref_cachep; 193 extern struct kmem_cache *btrfs_delayed_extent_op_cachep; 194 195 int __init btrfs_delayed_ref_init(void); 196 void __cold btrfs_delayed_ref_exit(void); 197 198 static inline struct btrfs_delayed_extent_op * 199 btrfs_alloc_delayed_extent_op(void) 200 { 201 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS); 202 } 203 204 static inline void 205 btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op) 206 { 207 if (op) 208 kmem_cache_free(btrfs_delayed_extent_op_cachep, op); 209 } 210 211 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) 212 { 213 WARN_ON(refcount_read(&ref->refs) == 0); 214 if (refcount_dec_and_test(&ref->refs)) { 215 WARN_ON(ref->in_tree); 216 switch (ref->type) { 217 case BTRFS_TREE_BLOCK_REF_KEY: 218 case BTRFS_SHARED_BLOCK_REF_KEY: 219 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref); 220 break; 221 case BTRFS_EXTENT_DATA_REF_KEY: 222 case BTRFS_SHARED_DATA_REF_KEY: 223 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref); 224 break; 225 default: 226 BUG(); 227 } 228 } 229 } 230 231 static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *head) 232 { 233 if (refcount_dec_and_test(&head->refs)) 234 kmem_cache_free(btrfs_delayed_ref_head_cachep, head); 235 } 236 237 int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans, 238 u64 bytenr, u64 num_bytes, u64 parent, 239 u64 ref_root, int level, int action, 240 struct btrfs_delayed_extent_op *extent_op, 241 int *old_ref_mod, int *new_ref_mod); 242 int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans, 243 u64 bytenr, u64 num_bytes, 244 u64 parent, u64 ref_root, 245 u64 owner, u64 offset, u64 reserved, int action, 246 int *old_ref_mod, int *new_ref_mod); 247 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info, 248 struct btrfs_trans_handle *trans, 249 u64 bytenr, u64 num_bytes, 250 struct btrfs_delayed_extent_op *extent_op); 251 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans, 252 struct btrfs_delayed_ref_root *delayed_refs, 253 struct btrfs_delayed_ref_head *head); 254 255 struct btrfs_delayed_ref_head * 256 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, 257 u64 bytenr); 258 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, 259 struct btrfs_delayed_ref_head *head); 260 static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head) 261 { 262 mutex_unlock(&head->mutex); 263 } 264 265 266 struct btrfs_delayed_ref_head * 267 btrfs_select_ref_head(struct btrfs_trans_handle *trans); 268 269 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq); 270 271 /* 272 * helper functions to cast a node into its container 273 */ 274 static inline struct btrfs_delayed_tree_ref * 275 btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node) 276 { 277 return container_of(node, struct btrfs_delayed_tree_ref, node); 278 } 279 280 static inline struct btrfs_delayed_data_ref * 281 btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node) 282 { 283 return container_of(node, struct btrfs_delayed_data_ref, node); 284 } 285 286 #endif 287