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->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 /* ref count on this data structure */ 37 atomic_t refs; 38 39 /* 40 * how many refs is this entry adding or deleting. For 41 * head refs, this may be a negative number because it is keeping 42 * track of the total mods done to the reference count. 43 * For individual refs, this will always be a positive number 44 * 45 * It may be more than one, since it is possible for a single 46 * parent to have more than one ref on an extent 47 */ 48 int ref_mod; 49 50 unsigned int action:8; 51 unsigned int type:8; 52 /* is this node still in the rbtree? */ 53 unsigned int is_head:1; 54 unsigned int in_tree:1; 55 }; 56 57 struct btrfs_delayed_extent_op { 58 struct btrfs_disk_key key; 59 u64 flags_to_set; 60 unsigned int update_key:1; 61 unsigned int update_flags:1; 62 unsigned int is_data:1; 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 struct btrfs_delayed_ref_node node; 73 74 /* 75 * the mutex is held while running the refs, and it is also 76 * held when checking the sum of reference modifications. 77 */ 78 struct mutex mutex; 79 80 struct list_head cluster; 81 82 struct btrfs_delayed_extent_op *extent_op; 83 /* 84 * when a new extent is allocated, it is just reserved in memory 85 * The actual extent isn't inserted into the extent allocation tree 86 * until the delayed ref is processed. must_insert_reserved is 87 * used to flag a delayed ref so the accounting can be updated 88 * when a full insert is done. 89 * 90 * It is possible the extent will be freed before it is ever 91 * inserted into the extent allocation tree. In this case 92 * we need to update the in ram accounting to properly reflect 93 * the free has happened. 94 */ 95 unsigned int must_insert_reserved:1; 96 unsigned int is_data:1; 97 }; 98 99 struct btrfs_delayed_tree_ref { 100 struct btrfs_delayed_ref_node node; 101 union { 102 u64 root; 103 u64 parent; 104 }; 105 int level; 106 }; 107 108 struct btrfs_delayed_data_ref { 109 struct btrfs_delayed_ref_node node; 110 union { 111 u64 root; 112 u64 parent; 113 }; 114 u64 objectid; 115 u64 offset; 116 }; 117 118 struct btrfs_delayed_ref_root { 119 struct rb_root root; 120 121 /* this spin lock protects the rbtree and the entries inside */ 122 spinlock_t lock; 123 124 /* how many delayed ref updates we've queued, used by the 125 * throttling code 126 */ 127 unsigned long num_entries; 128 129 /* total number of head nodes in tree */ 130 unsigned long num_heads; 131 132 /* total number of head nodes ready for processing */ 133 unsigned long num_heads_ready; 134 135 /* 136 * set when the tree is flushing before a transaction commit, 137 * used by the throttling code to decide if new updates need 138 * to be run right away 139 */ 140 int flushing; 141 142 u64 run_delayed_start; 143 }; 144 145 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) 146 { 147 WARN_ON(atomic_read(&ref->refs) == 0); 148 if (atomic_dec_and_test(&ref->refs)) { 149 WARN_ON(ref->in_tree); 150 kfree(ref); 151 } 152 } 153 154 int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans, 155 u64 bytenr, u64 num_bytes, u64 parent, 156 u64 ref_root, int level, int action, 157 struct btrfs_delayed_extent_op *extent_op); 158 int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans, 159 u64 bytenr, u64 num_bytes, 160 u64 parent, u64 ref_root, 161 u64 owner, u64 offset, int action, 162 struct btrfs_delayed_extent_op *extent_op); 163 int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans, 164 u64 bytenr, u64 num_bytes, 165 struct btrfs_delayed_extent_op *extent_op); 166 167 struct btrfs_delayed_ref_head * 168 btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr); 169 int btrfs_delayed_ref_pending(struct btrfs_trans_handle *trans, u64 bytenr); 170 int btrfs_update_delayed_ref(struct btrfs_trans_handle *trans, 171 u64 bytenr, u64 num_bytes, u64 orig_parent, 172 u64 parent, u64 orig_ref_root, u64 ref_root, 173 u64 orig_ref_generation, u64 ref_generation, 174 u64 owner_objectid, int pin); 175 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, 176 struct btrfs_delayed_ref_head *head); 177 int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans, 178 struct list_head *cluster, u64 search_start); 179 /* 180 * a node might live in a head or a regular ref, this lets you 181 * test for the proper type to use. 182 */ 183 static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node) 184 { 185 return node->is_head; 186 } 187 188 /* 189 * helper functions to cast a node into its container 190 */ 191 static inline struct btrfs_delayed_tree_ref * 192 btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node) 193 { 194 WARN_ON(btrfs_delayed_ref_is_head(node)); 195 return container_of(node, struct btrfs_delayed_tree_ref, node); 196 } 197 198 static inline struct btrfs_delayed_data_ref * 199 btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node) 200 { 201 WARN_ON(btrfs_delayed_ref_is_head(node)); 202 return container_of(node, struct btrfs_delayed_data_ref, node); 203 } 204 205 static inline struct btrfs_delayed_ref_head * 206 btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node) 207 { 208 WARN_ON(!btrfs_delayed_ref_is_head(node)); 209 return container_of(node, struct btrfs_delayed_ref_head, node); 210 } 211 #endif 212