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
btrfs_put_delayed_ref(struct btrfs_delayed_ref_node * ref)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 */
btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node * node)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 *
btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node * node)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 *
btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node * node)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 *
btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node * node)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