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 /* these are the possible values of struct btrfs_delayed_ref_node->action */ 22 #define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */ 23 #define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */ 24 #define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */ 25 #define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */ 26 27 struct btrfs_delayed_ref_node { 28 struct rb_node rb_node; 29 30 /* the starting bytenr of the extent */ 31 u64 bytenr; 32 33 /* the size of the extent */ 34 u64 num_bytes; 35 36 /* seq number to keep track of insertion order */ 37 u64 seq; 38 39 /* ref count on this data structure */ 40 atomic_t refs; 41 42 /* 43 * how many refs is this entry adding or deleting. For 44 * head refs, this may be a negative number because it is keeping 45 * track of the total mods done to the reference count. 46 * For individual refs, this will always be a positive number 47 * 48 * It may be more than one, since it is possible for a single 49 * parent to have more than one ref on an extent 50 */ 51 int ref_mod; 52 53 unsigned int action:8; 54 unsigned int type:8; 55 unsigned int no_quota:1; 56 /* is this node still in the rbtree? */ 57 unsigned int is_head:1; 58 unsigned int in_tree:1; 59 }; 60 61 struct btrfs_delayed_extent_op { 62 struct btrfs_disk_key key; 63 u64 flags_to_set; 64 int level; 65 unsigned int update_key:1; 66 unsigned int update_flags:1; 67 unsigned int is_data:1; 68 }; 69 70 /* 71 * the head refs are used to hold a lock on a given extent, which allows us 72 * to make sure that only one process is running the delayed refs 73 * at a time for a single extent. They also store the sum of all the 74 * reference count modifications we've queued up. 75 */ 76 struct btrfs_delayed_ref_head { 77 struct btrfs_delayed_ref_node node; 78 79 /* 80 * the mutex is held while running the refs, and it is also 81 * held when checking the sum of reference modifications. 82 */ 83 struct mutex mutex; 84 85 spinlock_t lock; 86 struct rb_root ref_root; 87 88 struct rb_node href_node; 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 * when a new extent is allocated, it is just reserved in memory 101 * The actual extent isn't inserted into the extent allocation tree 102 * until the delayed ref is processed. must_insert_reserved is 103 * used to flag a delayed ref so the accounting can be updated 104 * when a full insert is done. 105 * 106 * It is possible the extent will be freed before it is ever 107 * inserted into the extent allocation tree. In this case 108 * we need to update the in ram accounting to properly reflect 109 * the free has happened. 110 */ 111 unsigned int must_insert_reserved:1; 112 unsigned int is_data:1; 113 unsigned int processing:1; 114 }; 115 116 struct btrfs_delayed_tree_ref { 117 struct btrfs_delayed_ref_node node; 118 u64 root; 119 u64 parent; 120 int level; 121 }; 122 123 struct btrfs_delayed_data_ref { 124 struct btrfs_delayed_ref_node node; 125 u64 root; 126 u64 parent; 127 u64 objectid; 128 u64 offset; 129 }; 130 131 struct btrfs_delayed_ref_root { 132 /* head ref rbtree */ 133 struct rb_root href_root; 134 135 /* this spin lock protects the rbtree and the entries inside */ 136 spinlock_t lock; 137 138 /* how many delayed ref updates we've queued, used by the 139 * throttling code 140 */ 141 atomic_t num_entries; 142 143 /* total number of head nodes in tree */ 144 unsigned long num_heads; 145 146 /* total number of head nodes ready for processing */ 147 unsigned long num_heads_ready; 148 149 u64 pending_csums; 150 151 /* 152 * set when the tree is flushing before a transaction commit, 153 * used by the throttling code to decide if new updates need 154 * to be run right away 155 */ 156 int flushing; 157 158 u64 run_delayed_start; 159 }; 160 161 extern struct kmem_cache *btrfs_delayed_ref_head_cachep; 162 extern struct kmem_cache *btrfs_delayed_tree_ref_cachep; 163 extern struct kmem_cache *btrfs_delayed_data_ref_cachep; 164 extern struct kmem_cache *btrfs_delayed_extent_op_cachep; 165 166 int btrfs_delayed_ref_init(void); 167 void btrfs_delayed_ref_exit(void); 168 169 static inline struct btrfs_delayed_extent_op * 170 btrfs_alloc_delayed_extent_op(void) 171 { 172 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS); 173 } 174 175 static inline void 176 btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op) 177 { 178 if (op) 179 kmem_cache_free(btrfs_delayed_extent_op_cachep, op); 180 } 181 182 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) 183 { 184 WARN_ON(atomic_read(&ref->refs) == 0); 185 if (atomic_dec_and_test(&ref->refs)) { 186 WARN_ON(ref->in_tree); 187 switch (ref->type) { 188 case BTRFS_TREE_BLOCK_REF_KEY: 189 case BTRFS_SHARED_BLOCK_REF_KEY: 190 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref); 191 break; 192 case BTRFS_EXTENT_DATA_REF_KEY: 193 case BTRFS_SHARED_DATA_REF_KEY: 194 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref); 195 break; 196 case 0: 197 kmem_cache_free(btrfs_delayed_ref_head_cachep, ref); 198 break; 199 default: 200 BUG(); 201 } 202 } 203 } 204 205 int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info, 206 struct btrfs_trans_handle *trans, 207 u64 bytenr, u64 num_bytes, u64 parent, 208 u64 ref_root, int level, int action, 209 struct btrfs_delayed_extent_op *extent_op, 210 int no_quota); 211 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info, 212 struct btrfs_trans_handle *trans, 213 u64 bytenr, u64 num_bytes, 214 u64 parent, u64 ref_root, 215 u64 owner, u64 offset, int action, 216 struct btrfs_delayed_extent_op *extent_op, 217 int no_quota); 218 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info, 219 struct btrfs_trans_handle *trans, 220 u64 bytenr, u64 num_bytes, 221 struct btrfs_delayed_extent_op *extent_op); 222 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans, 223 struct btrfs_fs_info *fs_info, 224 struct btrfs_delayed_ref_root *delayed_refs, 225 struct btrfs_delayed_ref_head *head); 226 227 struct btrfs_delayed_ref_head * 228 btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr); 229 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, 230 struct btrfs_delayed_ref_head *head); 231 static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head) 232 { 233 mutex_unlock(&head->mutex); 234 } 235 236 237 struct btrfs_delayed_ref_head * 238 btrfs_select_ref_head(struct btrfs_trans_handle *trans); 239 240 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, 241 struct btrfs_delayed_ref_root *delayed_refs, 242 u64 seq); 243 244 /* 245 * a node might live in a head or a regular ref, this lets you 246 * test for the proper type to use. 247 */ 248 static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node) 249 { 250 return node->is_head; 251 } 252 253 /* 254 * helper functions to cast a node into its container 255 */ 256 static inline struct btrfs_delayed_tree_ref * 257 btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node) 258 { 259 WARN_ON(btrfs_delayed_ref_is_head(node)); 260 return container_of(node, struct btrfs_delayed_tree_ref, node); 261 } 262 263 static inline struct btrfs_delayed_data_ref * 264 btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node) 265 { 266 WARN_ON(btrfs_delayed_ref_is_head(node)); 267 return container_of(node, struct btrfs_delayed_data_ref, node); 268 } 269 270 static inline struct btrfs_delayed_ref_head * 271 btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node) 272 { 273 WARN_ON(!btrfs_delayed_ref_is_head(node)); 274 return container_of(node, struct btrfs_delayed_ref_head, node); 275 } 276 #endif 277