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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 | ||
56bec294 CM |
33 | /* the size of the extent */ |
34 | u64 num_bytes; | |
35 | ||
00f04b88 AJ |
36 | /* seq number to keep track of insertion order */ |
37 | u64 seq; | |
38 | ||
56bec294 CM |
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 | ||
5d4f98a2 YZ |
53 | unsigned int action:8; |
54 | unsigned int type:8; | |
56bec294 | 55 | /* is this node still in the rbtree? */ |
5d4f98a2 | 56 | unsigned int is_head:1; |
56bec294 CM |
57 | unsigned int in_tree:1; |
58 | }; | |
59 | ||
5d4f98a2 YZ |
60 | struct btrfs_delayed_extent_op { |
61 | struct btrfs_disk_key key; | |
62 | u64 flags_to_set; | |
63 | unsigned int update_key:1; | |
64 | unsigned int update_flags:1; | |
65 | unsigned int is_data:1; | |
66 | }; | |
67 | ||
56bec294 CM |
68 | /* |
69 | * the head refs are used to hold a lock on a given extent, which allows us | |
70 | * to make sure that only one process is running the delayed refs | |
71 | * at a time for a single extent. They also store the sum of all the | |
72 | * reference count modifications we've queued up. | |
73 | */ | |
74 | struct btrfs_delayed_ref_head { | |
75 | struct btrfs_delayed_ref_node node; | |
76 | ||
77 | /* | |
78 | * the mutex is held while running the refs, and it is also | |
79 | * held when checking the sum of reference modifications. | |
80 | */ | |
81 | struct mutex mutex; | |
82 | ||
c3e69d58 CM |
83 | struct list_head cluster; |
84 | ||
5d4f98a2 | 85 | struct btrfs_delayed_extent_op *extent_op; |
56bec294 CM |
86 | /* |
87 | * when a new extent is allocated, it is just reserved in memory | |
88 | * The actual extent isn't inserted into the extent allocation tree | |
89 | * until the delayed ref is processed. must_insert_reserved is | |
90 | * used to flag a delayed ref so the accounting can be updated | |
91 | * when a full insert is done. | |
92 | * | |
93 | * It is possible the extent will be freed before it is ever | |
94 | * inserted into the extent allocation tree. In this case | |
95 | * we need to update the in ram accounting to properly reflect | |
96 | * the free has happened. | |
97 | */ | |
98 | unsigned int must_insert_reserved:1; | |
5d4f98a2 | 99 | unsigned int is_data:1; |
56bec294 CM |
100 | }; |
101 | ||
5d4f98a2 | 102 | struct btrfs_delayed_tree_ref { |
56bec294 | 103 | struct btrfs_delayed_ref_node node; |
eebe063b AJ |
104 | u64 root; |
105 | u64 parent; | |
5d4f98a2 YZ |
106 | int level; |
107 | }; | |
56bec294 | 108 | |
5d4f98a2 YZ |
109 | struct btrfs_delayed_data_ref { |
110 | struct btrfs_delayed_ref_node node; | |
eebe063b AJ |
111 | u64 root; |
112 | u64 parent; | |
5d4f98a2 YZ |
113 | u64 objectid; |
114 | u64 offset; | |
56bec294 CM |
115 | }; |
116 | ||
117 | struct btrfs_delayed_ref_root { | |
118 | struct rb_root root; | |
119 | ||
120 | /* this spin lock protects the rbtree and the entries inside */ | |
121 | spinlock_t lock; | |
122 | ||
123 | /* how many delayed ref updates we've queued, used by the | |
124 | * throttling code | |
125 | */ | |
126 | unsigned long num_entries; | |
127 | ||
c3e69d58 CM |
128 | /* total number of head nodes in tree */ |
129 | unsigned long num_heads; | |
130 | ||
131 | /* total number of head nodes ready for processing */ | |
132 | unsigned long num_heads_ready; | |
133 | ||
56bec294 CM |
134 | /* |
135 | * set when the tree is flushing before a transaction commit, | |
136 | * used by the throttling code to decide if new updates need | |
137 | * to be run right away | |
138 | */ | |
139 | int flushing; | |
c3e69d58 CM |
140 | |
141 | u64 run_delayed_start; | |
00f04b88 AJ |
142 | |
143 | /* | |
144 | * seq number of delayed refs. We need to know if a backref was being | |
145 | * added before the currently processed ref or afterwards. | |
146 | */ | |
147 | u64 seq; | |
148 | ||
149 | /* | |
150 | * seq_list holds a list of all seq numbers that are currently being | |
151 | * added to the list. While walking backrefs (btrfs_find_all_roots, | |
152 | * qgroups), which might take some time, no newer ref must be processed, | |
153 | * as it might influence the outcome of the walk. | |
154 | */ | |
155 | struct list_head seq_head; | |
a168650c JS |
156 | |
157 | /* | |
158 | * when the only refs we have in the list must not be processed, we want | |
159 | * to wait for more refs to show up or for the end of backref walking. | |
160 | */ | |
161 | wait_queue_head_t seq_wait; | |
56bec294 CM |
162 | }; |
163 | ||
164 | static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) | |
165 | { | |
166 | WARN_ON(atomic_read(&ref->refs) == 0); | |
167 | if (atomic_dec_and_test(&ref->refs)) { | |
168 | WARN_ON(ref->in_tree); | |
169 | kfree(ref); | |
170 | } | |
171 | } | |
172 | ||
66d7e7f0 AJ |
173 | int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info, |
174 | struct btrfs_trans_handle *trans, | |
5d4f98a2 YZ |
175 | u64 bytenr, u64 num_bytes, u64 parent, |
176 | u64 ref_root, int level, int action, | |
66d7e7f0 AJ |
177 | struct btrfs_delayed_extent_op *extent_op, |
178 | int for_cow); | |
179 | int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info, | |
180 | struct btrfs_trans_handle *trans, | |
5d4f98a2 YZ |
181 | u64 bytenr, u64 num_bytes, |
182 | u64 parent, u64 ref_root, | |
183 | u64 owner, u64 offset, int action, | |
66d7e7f0 AJ |
184 | struct btrfs_delayed_extent_op *extent_op, |
185 | int for_cow); | |
186 | int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info, | |
187 | struct btrfs_trans_handle *trans, | |
5d4f98a2 YZ |
188 | u64 bytenr, u64 num_bytes, |
189 | struct btrfs_delayed_extent_op *extent_op); | |
56bec294 | 190 | |
1887be66 CM |
191 | struct btrfs_delayed_ref_head * |
192 | btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr); | |
c3e69d58 CM |
193 | int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, |
194 | struct btrfs_delayed_ref_head *head); | |
195 | int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans, | |
196 | struct list_head *cluster, u64 search_start); | |
00f04b88 AJ |
197 | |
198 | struct seq_list { | |
199 | struct list_head list; | |
200 | u64 seq; | |
201 | }; | |
202 | ||
203 | static inline u64 inc_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs) | |
204 | { | |
205 | assert_spin_locked(&delayed_refs->lock); | |
206 | ++delayed_refs->seq; | |
207 | return delayed_refs->seq; | |
208 | } | |
209 | ||
210 | static inline void | |
211 | btrfs_get_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs, | |
212 | struct seq_list *elem) | |
213 | { | |
214 | assert_spin_locked(&delayed_refs->lock); | |
215 | elem->seq = delayed_refs->seq; | |
216 | list_add_tail(&elem->list, &delayed_refs->seq_head); | |
217 | } | |
218 | ||
219 | static inline void | |
220 | btrfs_put_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs, | |
221 | struct seq_list *elem) | |
222 | { | |
223 | spin_lock(&delayed_refs->lock); | |
224 | list_del(&elem->list); | |
a168650c | 225 | wake_up(&delayed_refs->seq_wait); |
00f04b88 AJ |
226 | spin_unlock(&delayed_refs->lock); |
227 | } | |
228 | ||
229 | int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs, | |
230 | u64 seq); | |
231 | ||
232 | /* | |
233 | * delayed refs with a ref_seq > 0 must be held back during backref walking. | |
234 | * this only applies to items in one of the fs-trees. for_cow items never need | |
235 | * to be held back, so they won't get a ref_seq number. | |
236 | */ | |
237 | static inline int need_ref_seq(int for_cow, u64 rootid) | |
238 | { | |
239 | if (for_cow) | |
240 | return 0; | |
241 | ||
242 | if (rootid == BTRFS_FS_TREE_OBJECTID) | |
243 | return 1; | |
244 | ||
245 | if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID) | |
246 | return 1; | |
247 | ||
248 | return 0; | |
249 | } | |
250 | ||
56bec294 CM |
251 | /* |
252 | * a node might live in a head or a regular ref, this lets you | |
253 | * test for the proper type to use. | |
254 | */ | |
255 | static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node) | |
256 | { | |
5d4f98a2 | 257 | return node->is_head; |
56bec294 CM |
258 | } |
259 | ||
260 | /* | |
261 | * helper functions to cast a node into its container | |
262 | */ | |
5d4f98a2 YZ |
263 | static inline struct btrfs_delayed_tree_ref * |
264 | btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node) | |
56bec294 CM |
265 | { |
266 | WARN_ON(btrfs_delayed_ref_is_head(node)); | |
5d4f98a2 YZ |
267 | return container_of(node, struct btrfs_delayed_tree_ref, node); |
268 | } | |
56bec294 | 269 | |
5d4f98a2 YZ |
270 | static inline struct btrfs_delayed_data_ref * |
271 | btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node) | |
272 | { | |
273 | WARN_ON(btrfs_delayed_ref_is_head(node)); | |
274 | return container_of(node, struct btrfs_delayed_data_ref, node); | |
56bec294 CM |
275 | } |
276 | ||
277 | static inline struct btrfs_delayed_ref_head * | |
278 | btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node) | |
279 | { | |
280 | WARN_ON(!btrfs_delayed_ref_is_head(node)); | |
281 | return container_of(node, struct btrfs_delayed_ref_head, node); | |
56bec294 CM |
282 | } |
283 | #endif |