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56bec294 CM |
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 */ | |
1a81af4d | 25 | #define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */ |
56bec294 CM |
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 parent our backref will point to */ | |
34 | u64 parent; | |
35 | ||
36 | /* the size of the extent */ | |
37 | u64 num_bytes; | |
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 | /* is this node still in the rbtree? */ | |
54 | unsigned int in_tree:1; | |
55 | }; | |
56 | ||
57 | /* | |
58 | * the head refs are used to hold a lock on a given extent, which allows us | |
59 | * to make sure that only one process is running the delayed refs | |
60 | * at a time for a single extent. They also store the sum of all the | |
61 | * reference count modifications we've queued up. | |
62 | */ | |
63 | struct btrfs_delayed_ref_head { | |
64 | struct btrfs_delayed_ref_node node; | |
65 | ||
66 | /* | |
67 | * the mutex is held while running the refs, and it is also | |
68 | * held when checking the sum of reference modifications. | |
69 | */ | |
70 | struct mutex mutex; | |
71 | ||
c3e69d58 CM |
72 | struct list_head cluster; |
73 | ||
56bec294 CM |
74 | /* |
75 | * when a new extent is allocated, it is just reserved in memory | |
76 | * The actual extent isn't inserted into the extent allocation tree | |
77 | * until the delayed ref is processed. must_insert_reserved is | |
78 | * used to flag a delayed ref so the accounting can be updated | |
79 | * when a full insert is done. | |
80 | * | |
81 | * It is possible the extent will be freed before it is ever | |
82 | * inserted into the extent allocation tree. In this case | |
83 | * we need to update the in ram accounting to properly reflect | |
84 | * the free has happened. | |
85 | */ | |
86 | unsigned int must_insert_reserved:1; | |
87 | }; | |
88 | ||
89 | struct btrfs_delayed_ref { | |
90 | struct btrfs_delayed_ref_node node; | |
91 | ||
92 | /* the root objectid our ref will point to */ | |
93 | u64 root; | |
94 | ||
95 | /* the generation for the backref */ | |
96 | u64 generation; | |
97 | ||
98 | /* owner_objectid of the backref */ | |
99 | u64 owner_objectid; | |
100 | ||
101 | /* operation done by this entry in the rbtree */ | |
102 | u8 action; | |
103 | ||
104 | /* if pin == 1, when the extent is freed it will be pinned until | |
105 | * transaction commit | |
106 | */ | |
107 | unsigned int pin:1; | |
108 | }; | |
109 | ||
110 | struct btrfs_delayed_ref_root { | |
111 | struct rb_root root; | |
112 | ||
113 | /* this spin lock protects the rbtree and the entries inside */ | |
114 | spinlock_t lock; | |
115 | ||
116 | /* how many delayed ref updates we've queued, used by the | |
117 | * throttling code | |
118 | */ | |
119 | unsigned long num_entries; | |
120 | ||
c3e69d58 CM |
121 | /* total number of head nodes in tree */ |
122 | unsigned long num_heads; | |
123 | ||
124 | /* total number of head nodes ready for processing */ | |
125 | unsigned long num_heads_ready; | |
126 | ||
56bec294 CM |
127 | /* |
128 | * set when the tree is flushing before a transaction commit, | |
129 | * used by the throttling code to decide if new updates need | |
130 | * to be run right away | |
131 | */ | |
132 | int flushing; | |
c3e69d58 CM |
133 | |
134 | u64 run_delayed_start; | |
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135 | }; |
136 | ||
137 | static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) | |
138 | { | |
139 | WARN_ON(atomic_read(&ref->refs) == 0); | |
140 | if (atomic_dec_and_test(&ref->refs)) { | |
141 | WARN_ON(ref->in_tree); | |
142 | kfree(ref); | |
143 | } | |
144 | } | |
145 | ||
146 | int btrfs_add_delayed_ref(struct btrfs_trans_handle *trans, | |
147 | u64 bytenr, u64 num_bytes, u64 parent, u64 ref_root, | |
148 | u64 ref_generation, u64 owner_objectid, int action, | |
149 | int pin); | |
150 | ||
1887be66 CM |
151 | struct btrfs_delayed_ref_head * |
152 | btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr); | |
56bec294 | 153 | int btrfs_delayed_ref_pending(struct btrfs_trans_handle *trans, u64 bytenr); |
56bec294 CM |
154 | int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans, |
155 | struct btrfs_root *root, u64 bytenr, | |
156 | u64 num_bytes, u32 *refs); | |
157 | int btrfs_update_delayed_ref(struct btrfs_trans_handle *trans, | |
158 | u64 bytenr, u64 num_bytes, u64 orig_parent, | |
159 | u64 parent, u64 orig_ref_root, u64 ref_root, | |
160 | u64 orig_ref_generation, u64 ref_generation, | |
161 | u64 owner_objectid, int pin); | |
c3e69d58 CM |
162 | int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, |
163 | struct btrfs_delayed_ref_head *head); | |
164 | int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans, | |
165 | struct list_head *cluster, u64 search_start); | |
56bec294 CM |
166 | /* |
167 | * a node might live in a head or a regular ref, this lets you | |
168 | * test for the proper type to use. | |
169 | */ | |
170 | static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node) | |
171 | { | |
172 | return node->parent == (u64)-1; | |
173 | } | |
174 | ||
175 | /* | |
176 | * helper functions to cast a node into its container | |
177 | */ | |
178 | static inline struct btrfs_delayed_ref * | |
179 | btrfs_delayed_node_to_ref(struct btrfs_delayed_ref_node *node) | |
180 | { | |
181 | WARN_ON(btrfs_delayed_ref_is_head(node)); | |
182 | return container_of(node, struct btrfs_delayed_ref, node); | |
183 | ||
184 | } | |
185 | ||
186 | static inline struct btrfs_delayed_ref_head * | |
187 | btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node) | |
188 | { | |
189 | WARN_ON(!btrfs_delayed_ref_is_head(node)); | |
190 | return container_of(node, struct btrfs_delayed_ref_head, node); | |
191 | ||
192 | } | |
193 | #endif |