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 * when a new extent is allocated, it is just reserved in memory 93 * The actual extent isn't inserted into the extent allocation tree 94 * until the delayed ref is processed. must_insert_reserved is 95 * used to flag a delayed ref so the accounting can be updated 96 * when a full insert is done. 97 * 98 * It is possible the extent will be freed before it is ever 99 * inserted into the extent allocation tree. In this case 100 * we need to update the in ram accounting to properly reflect 101 * the free has happened. 102 */ 103 unsigned int must_insert_reserved:1; 104 unsigned int is_data:1; 105 unsigned int processing:1; 106 }; 107 108 struct btrfs_delayed_tree_ref { 109 struct btrfs_delayed_ref_node node; 110 u64 root; 111 u64 parent; 112 int level; 113 }; 114 115 struct btrfs_delayed_data_ref { 116 struct btrfs_delayed_ref_node node; 117 u64 root; 118 u64 parent; 119 u64 objectid; 120 u64 offset; 121 }; 122 123 struct btrfs_delayed_ref_root { 124 /* head ref rbtree */ 125 struct rb_root href_root; 126 127 /* this spin lock protects the rbtree and the entries inside */ 128 spinlock_t lock; 129 130 /* how many delayed ref updates we've queued, used by the 131 * throttling code 132 */ 133 atomic_t num_entries; 134 135 /* total number of head nodes in tree */ 136 unsigned long num_heads; 137 138 /* total number of head nodes ready for processing */ 139 unsigned long num_heads_ready; 140 141 /* 142 * set when the tree is flushing before a transaction commit, 143 * used by the throttling code to decide if new updates need 144 * to be run right away 145 */ 146 int flushing; 147 148 u64 run_delayed_start; 149 }; 150 151 extern struct kmem_cache *btrfs_delayed_ref_head_cachep; 152 extern struct kmem_cache *btrfs_delayed_tree_ref_cachep; 153 extern struct kmem_cache *btrfs_delayed_data_ref_cachep; 154 extern struct kmem_cache *btrfs_delayed_extent_op_cachep; 155 156 int btrfs_delayed_ref_init(void); 157 void btrfs_delayed_ref_exit(void); 158 159 static inline struct btrfs_delayed_extent_op * 160 btrfs_alloc_delayed_extent_op(void) 161 { 162 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS); 163 } 164 165 static inline void 166 btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op) 167 { 168 if (op) 169 kmem_cache_free(btrfs_delayed_extent_op_cachep, op); 170 } 171 172 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) 173 { 174 WARN_ON(atomic_read(&ref->refs) == 0); 175 if (atomic_dec_and_test(&ref->refs)) { 176 WARN_ON(ref->in_tree); 177 switch (ref->type) { 178 case BTRFS_TREE_BLOCK_REF_KEY: 179 case BTRFS_SHARED_BLOCK_REF_KEY: 180 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref); 181 break; 182 case BTRFS_EXTENT_DATA_REF_KEY: 183 case BTRFS_SHARED_DATA_REF_KEY: 184 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref); 185 break; 186 case 0: 187 kmem_cache_free(btrfs_delayed_ref_head_cachep, ref); 188 break; 189 default: 190 BUG(); 191 } 192 } 193 } 194 195 int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info, 196 struct btrfs_trans_handle *trans, 197 u64 bytenr, u64 num_bytes, u64 parent, 198 u64 ref_root, int level, int action, 199 struct btrfs_delayed_extent_op *extent_op, 200 int no_quota); 201 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info, 202 struct btrfs_trans_handle *trans, 203 u64 bytenr, u64 num_bytes, 204 u64 parent, u64 ref_root, 205 u64 owner, u64 offset, int action, 206 struct btrfs_delayed_extent_op *extent_op, 207 int no_quota); 208 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info, 209 struct btrfs_trans_handle *trans, 210 u64 bytenr, u64 num_bytes, 211 struct btrfs_delayed_extent_op *extent_op); 212 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans, 213 struct btrfs_fs_info *fs_info, 214 struct btrfs_delayed_ref_root *delayed_refs, 215 struct btrfs_delayed_ref_head *head); 216 217 struct btrfs_delayed_ref_head * 218 btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr); 219 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, 220 struct btrfs_delayed_ref_head *head); 221 static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head) 222 { 223 mutex_unlock(&head->mutex); 224 } 225 226 227 struct btrfs_delayed_ref_head * 228 btrfs_select_ref_head(struct btrfs_trans_handle *trans); 229 230 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, 231 struct btrfs_delayed_ref_root *delayed_refs, 232 u64 seq); 233 234 /* 235 * a node might live in a head or a regular ref, this lets you 236 * test for the proper type to use. 237 */ 238 static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node) 239 { 240 return node->is_head; 241 } 242 243 /* 244 * helper functions to cast a node into its container 245 */ 246 static inline struct btrfs_delayed_tree_ref * 247 btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node) 248 { 249 WARN_ON(btrfs_delayed_ref_is_head(node)); 250 return container_of(node, struct btrfs_delayed_tree_ref, node); 251 } 252 253 static inline struct btrfs_delayed_data_ref * 254 btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node) 255 { 256 WARN_ON(btrfs_delayed_ref_is_head(node)); 257 return container_of(node, struct btrfs_delayed_data_ref, node); 258 } 259 260 static inline struct btrfs_delayed_ref_head * 261 btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node) 262 { 263 WARN_ON(!btrfs_delayed_ref_is_head(node)); 264 return container_of(node, struct btrfs_delayed_ref_head, node); 265 } 266 #endif 267