1 /* 2 * Copyright (C) 2008 Oracle. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 */ 18 #ifndef __DELAYED_REF__ 19 #define __DELAYED_REF__ 20 21 #include <linux/refcount.h> 22 23 /* these are the possible values of struct btrfs_delayed_ref_node->action */ 24 #define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */ 25 #define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */ 26 #define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */ 27 #define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */ 28 29 struct btrfs_delayed_ref_node { 30 struct rb_node ref_node; 31 /* 32 * If action is BTRFS_ADD_DELAYED_REF, also link this node to 33 * ref_head->ref_add_list, then we do not need to iterate the 34 * whole ref_head->ref_list to find BTRFS_ADD_DELAYED_REF nodes. 35 */ 36 struct list_head add_list; 37 38 /* the starting bytenr of the extent */ 39 u64 bytenr; 40 41 /* the size of the extent */ 42 u64 num_bytes; 43 44 /* seq number to keep track of insertion order */ 45 u64 seq; 46 47 /* ref count on this data structure */ 48 refcount_t refs; 49 50 /* 51 * how many refs is this entry adding or deleting. For 52 * head refs, this may be a negative number because it is keeping 53 * track of the total mods done to the reference count. 54 * For individual refs, this will always be a positive number 55 * 56 * It may be more than one, since it is possible for a single 57 * parent to have more than one ref on an extent 58 */ 59 int ref_mod; 60 61 unsigned int action:8; 62 unsigned int type:8; 63 /* is this node still in the rbtree? */ 64 unsigned int is_head:1; 65 unsigned int in_tree:1; 66 }; 67 68 struct btrfs_delayed_extent_op { 69 struct btrfs_disk_key key; 70 u8 level; 71 bool update_key; 72 bool update_flags; 73 bool is_data; 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 */ 83 struct btrfs_delayed_ref_head { 84 u64 bytenr; 85 u64 num_bytes; 86 refcount_t refs; 87 /* 88 * the mutex is held while running the refs, and it is also 89 * held when checking the sum of reference modifications. 90 */ 91 struct mutex mutex; 92 93 spinlock_t lock; 94 struct rb_root ref_tree; 95 /* accumulate add BTRFS_ADD_DELAYED_REF nodes to this ref_add_list. */ 96 struct list_head ref_add_list; 97 98 struct rb_node href_node; 99 100 struct btrfs_delayed_extent_op *extent_op; 101 102 /* 103 * This is used to track the final ref_mod from all the refs associated 104 * with this head ref, this is not adjusted as delayed refs are run, 105 * this is meant to track if we need to do the csum accounting or not. 106 */ 107 int total_ref_mod; 108 109 /* 110 * This is the current outstanding mod references for this bytenr. This 111 * is used with lookup_extent_info to get an accurate reference count 112 * for a bytenr, so it is adjusted as delayed refs are run so that any 113 * on disk reference count + ref_mod is accurate. 114 */ 115 int ref_mod; 116 117 /* 118 * For qgroup reserved space freeing. 119 * 120 * ref_root and reserved will be recorded after 121 * BTRFS_ADD_DELAYED_EXTENT is called. 122 * And will be used to free reserved qgroup space at 123 * run_delayed_refs() time. 124 */ 125 u64 qgroup_ref_root; 126 u64 qgroup_reserved; 127 128 /* 129 * when a new extent is allocated, it is just reserved in memory 130 * The actual extent isn't inserted into the extent allocation tree 131 * until the delayed ref is processed. must_insert_reserved is 132 * used to flag a delayed ref so the accounting can be updated 133 * when a full insert is done. 134 * 135 * It is possible the extent will be freed before it is ever 136 * inserted into the extent allocation tree. In this case 137 * we need to update the in ram accounting to properly reflect 138 * the free has happened. 139 */ 140 unsigned int must_insert_reserved:1; 141 unsigned int is_data:1; 142 unsigned int processing:1; 143 }; 144 145 struct btrfs_delayed_tree_ref { 146 struct btrfs_delayed_ref_node node; 147 u64 root; 148 u64 parent; 149 int level; 150 }; 151 152 struct btrfs_delayed_data_ref { 153 struct btrfs_delayed_ref_node node; 154 u64 root; 155 u64 parent; 156 u64 objectid; 157 u64 offset; 158 }; 159 160 struct btrfs_delayed_ref_root { 161 /* head ref rbtree */ 162 struct rb_root href_root; 163 164 /* dirty extent records */ 165 struct rb_root dirty_extent_root; 166 167 /* this spin lock protects the rbtree and the entries inside */ 168 spinlock_t lock; 169 170 /* how many delayed ref updates we've queued, used by the 171 * throttling code 172 */ 173 atomic_t num_entries; 174 175 /* total number of head nodes in tree */ 176 unsigned long num_heads; 177 178 /* total number of head nodes ready for processing */ 179 unsigned long num_heads_ready; 180 181 u64 pending_csums; 182 183 /* 184 * set when the tree is flushing before a transaction commit, 185 * used by the throttling code to decide if new updates need 186 * to be run right away 187 */ 188 int flushing; 189 190 u64 run_delayed_start; 191 192 /* 193 * To make qgroup to skip given root. 194 * This is for snapshot, as btrfs_qgroup_inherit() will manually 195 * modify counters for snapshot and its source, so we should skip 196 * the snapshot in new_root/old_roots or it will get calculated twice 197 */ 198 u64 qgroup_to_skip; 199 }; 200 201 extern struct kmem_cache *btrfs_delayed_ref_head_cachep; 202 extern struct kmem_cache *btrfs_delayed_tree_ref_cachep; 203 extern struct kmem_cache *btrfs_delayed_data_ref_cachep; 204 extern struct kmem_cache *btrfs_delayed_extent_op_cachep; 205 206 int __init btrfs_delayed_ref_init(void); 207 void btrfs_delayed_ref_exit(void); 208 209 static inline struct btrfs_delayed_extent_op * 210 btrfs_alloc_delayed_extent_op(void) 211 { 212 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS); 213 } 214 215 static inline void 216 btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op) 217 { 218 if (op) 219 kmem_cache_free(btrfs_delayed_extent_op_cachep, op); 220 } 221 222 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) 223 { 224 WARN_ON(refcount_read(&ref->refs) == 0); 225 if (refcount_dec_and_test(&ref->refs)) { 226 WARN_ON(ref->in_tree); 227 switch (ref->type) { 228 case BTRFS_TREE_BLOCK_REF_KEY: 229 case BTRFS_SHARED_BLOCK_REF_KEY: 230 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref); 231 break; 232 case BTRFS_EXTENT_DATA_REF_KEY: 233 case BTRFS_SHARED_DATA_REF_KEY: 234 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref); 235 break; 236 default: 237 BUG(); 238 } 239 } 240 } 241 242 static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *head) 243 { 244 if (refcount_dec_and_test(&head->refs)) 245 kmem_cache_free(btrfs_delayed_ref_head_cachep, head); 246 } 247 248 int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info, 249 struct btrfs_trans_handle *trans, 250 u64 bytenr, u64 num_bytes, u64 parent, 251 u64 ref_root, int level, int action, 252 struct btrfs_delayed_extent_op *extent_op, 253 int *old_ref_mod, int *new_ref_mod); 254 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info, 255 struct btrfs_trans_handle *trans, 256 u64 bytenr, u64 num_bytes, 257 u64 parent, u64 ref_root, 258 u64 owner, u64 offset, u64 reserved, int action, 259 int *old_ref_mod, int *new_ref_mod); 260 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info, 261 struct btrfs_trans_handle *trans, 262 u64 bytenr, u64 num_bytes, 263 struct btrfs_delayed_extent_op *extent_op); 264 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans, 265 struct btrfs_fs_info *fs_info, 266 struct btrfs_delayed_ref_root *delayed_refs, 267 struct btrfs_delayed_ref_head *head); 268 269 struct btrfs_delayed_ref_head * 270 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, 271 u64 bytenr); 272 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, 273 struct btrfs_delayed_ref_head *head); 274 static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head) 275 { 276 mutex_unlock(&head->mutex); 277 } 278 279 280 struct btrfs_delayed_ref_head * 281 btrfs_select_ref_head(struct btrfs_trans_handle *trans); 282 283 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, 284 struct btrfs_delayed_ref_root *delayed_refs, 285 u64 seq); 286 287 /* 288 * helper functions to cast a node into its container 289 */ 290 static inline struct btrfs_delayed_tree_ref * 291 btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node) 292 { 293 return container_of(node, struct btrfs_delayed_tree_ref, node); 294 } 295 296 static inline struct btrfs_delayed_data_ref * 297 btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node) 298 { 299 return container_of(node, struct btrfs_delayed_data_ref, node); 300 } 301 #endif 302