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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
27struct 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
57struct 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 */
71struct 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
99struct 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
108struct 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
118struct 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
145static 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
154int 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);
158int 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);
163int 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
167struct btrfs_delayed_ref_head *
168btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
169int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
170 struct btrfs_delayed_ref_head *head);
171int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
172 struct list_head *cluster, u64 search_start);
173/*
174 * a node might live in a head or a regular ref, this lets you
175 * test for the proper type to use.
176 */
177static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
178{
179 return node->is_head;
180}
181
182/*
183 * helper functions to cast a node into its container
184 */
185static inline struct btrfs_delayed_tree_ref *
186btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
187{
188 WARN_ON(btrfs_delayed_ref_is_head(node));
189 return container_of(node, struct btrfs_delayed_tree_ref, node);
190}
191
192static inline struct btrfs_delayed_data_ref *
193btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
194{
195 WARN_ON(btrfs_delayed_ref_is_head(node));
196 return container_of(node, struct btrfs_delayed_data_ref, node);
197}
198
199static inline struct btrfs_delayed_ref_head *
200btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
201{
202 WARN_ON(!btrfs_delayed_ref_is_head(node));
203 return container_of(node, struct btrfs_delayed_ref_head, node);
204}
205#endif
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
27struct 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 /* is this node still in the rbtree? */
56 unsigned int is_head:1;
57 unsigned int in_tree:1;
58};
59
60struct btrfs_delayed_extent_op {
61 struct btrfs_disk_key key;
62 u64 flags_to_set;
63 int level;
64 unsigned int update_key:1;
65 unsigned int update_flags:1;
66 unsigned int is_data:1;
67};
68
69/*
70 * the head refs are used to hold a lock on a given extent, which allows us
71 * to make sure that only one process is running the delayed refs
72 * at a time for a single extent. They also store the sum of all the
73 * reference count modifications we've queued up.
74 */
75struct btrfs_delayed_ref_head {
76 struct btrfs_delayed_ref_node node;
77
78 /*
79 * the mutex is held while running the refs, and it is also
80 * held when checking the sum of reference modifications.
81 */
82 struct mutex mutex;
83
84 spinlock_t lock;
85 struct rb_root ref_root;
86
87 struct rb_node href_node;
88
89 struct btrfs_delayed_extent_op *extent_op;
90 /*
91 * when a new extent is allocated, it is just reserved in memory
92 * The actual extent isn't inserted into the extent allocation tree
93 * until the delayed ref is processed. must_insert_reserved is
94 * used to flag a delayed ref so the accounting can be updated
95 * when a full insert is done.
96 *
97 * It is possible the extent will be freed before it is ever
98 * inserted into the extent allocation tree. In this case
99 * we need to update the in ram accounting to properly reflect
100 * the free has happened.
101 */
102 unsigned int must_insert_reserved:1;
103 unsigned int is_data:1;
104 unsigned int processing:1;
105};
106
107struct btrfs_delayed_tree_ref {
108 struct btrfs_delayed_ref_node node;
109 u64 root;
110 u64 parent;
111 int level;
112};
113
114struct btrfs_delayed_data_ref {
115 struct btrfs_delayed_ref_node node;
116 u64 root;
117 u64 parent;
118 u64 objectid;
119 u64 offset;
120};
121
122struct btrfs_delayed_ref_root {
123 /* head ref rbtree */
124 struct rb_root href_root;
125
126 /* this spin lock protects the rbtree and the entries inside */
127 spinlock_t lock;
128
129 /* how many delayed ref updates we've queued, used by the
130 * throttling code
131 */
132 atomic_t num_entries;
133
134 /* total number of head nodes in tree */
135 unsigned long num_heads;
136
137 /* total number of head nodes ready for processing */
138 unsigned long num_heads_ready;
139
140 /*
141 * set when the tree is flushing before a transaction commit,
142 * used by the throttling code to decide if new updates need
143 * to be run right away
144 */
145 int flushing;
146
147 u64 run_delayed_start;
148};
149
150extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
151extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
152extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
153extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
154
155int btrfs_delayed_ref_init(void);
156void btrfs_delayed_ref_exit(void);
157
158static inline struct btrfs_delayed_extent_op *
159btrfs_alloc_delayed_extent_op(void)
160{
161 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
162}
163
164static inline void
165btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
166{
167 if (op)
168 kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
169}
170
171static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
172{
173 WARN_ON(atomic_read(&ref->refs) == 0);
174 if (atomic_dec_and_test(&ref->refs)) {
175 WARN_ON(ref->in_tree);
176 switch (ref->type) {
177 case BTRFS_TREE_BLOCK_REF_KEY:
178 case BTRFS_SHARED_BLOCK_REF_KEY:
179 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
180 break;
181 case BTRFS_EXTENT_DATA_REF_KEY:
182 case BTRFS_SHARED_DATA_REF_KEY:
183 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
184 break;
185 case 0:
186 kmem_cache_free(btrfs_delayed_ref_head_cachep, ref);
187 break;
188 default:
189 BUG();
190 }
191 }
192}
193
194int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
195 struct btrfs_trans_handle *trans,
196 u64 bytenr, u64 num_bytes, u64 parent,
197 u64 ref_root, int level, int action,
198 struct btrfs_delayed_extent_op *extent_op,
199 int for_cow);
200int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
201 struct btrfs_trans_handle *trans,
202 u64 bytenr, u64 num_bytes,
203 u64 parent, u64 ref_root,
204 u64 owner, u64 offset, int action,
205 struct btrfs_delayed_extent_op *extent_op,
206 int for_cow);
207int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
208 struct btrfs_trans_handle *trans,
209 u64 bytenr, u64 num_bytes,
210 struct btrfs_delayed_extent_op *extent_op);
211void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
212 struct btrfs_fs_info *fs_info,
213 struct btrfs_delayed_ref_root *delayed_refs,
214 struct btrfs_delayed_ref_head *head);
215
216struct btrfs_delayed_ref_head *
217btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
218int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
219 struct btrfs_delayed_ref_head *head);
220static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
221{
222 mutex_unlock(&head->mutex);
223}
224
225
226struct btrfs_delayed_ref_head *
227btrfs_select_ref_head(struct btrfs_trans_handle *trans);
228
229int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
230 struct btrfs_delayed_ref_root *delayed_refs,
231 u64 seq);
232
233/*
234 * delayed refs with a ref_seq > 0 must be held back during backref walking.
235 * this only applies to items in one of the fs-trees. for_cow items never need
236 * to be held back, so they won't get a ref_seq number.
237 */
238static inline int need_ref_seq(int for_cow, u64 rootid)
239{
240 if (for_cow)
241 return 0;
242
243 if (rootid == BTRFS_FS_TREE_OBJECTID)
244 return 1;
245
246 if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
247 return 1;
248
249 return 0;
250}
251
252/*
253 * a node might live in a head or a regular ref, this lets you
254 * test for the proper type to use.
255 */
256static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
257{
258 return node->is_head;
259}
260
261/*
262 * helper functions to cast a node into its container
263 */
264static inline struct btrfs_delayed_tree_ref *
265btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
266{
267 WARN_ON(btrfs_delayed_ref_is_head(node));
268 return container_of(node, struct btrfs_delayed_tree_ref, node);
269}
270
271static inline struct btrfs_delayed_data_ref *
272btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
273{
274 WARN_ON(btrfs_delayed_ref_is_head(node));
275 return container_of(node, struct btrfs_delayed_data_ref, node);
276}
277
278static inline struct btrfs_delayed_ref_head *
279btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
280{
281 WARN_ON(!btrfs_delayed_ref_is_head(node));
282 return container_of(node, struct btrfs_delayed_ref_head, node);
283}
284#endif