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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 /* 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 unsigned int update_key:1;
64 unsigned int update_flags:1;
65 unsigned int is_data:1;
66};
67
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 */
74struct 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
83 struct list_head cluster;
84
85 struct btrfs_delayed_extent_op *extent_op;
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;
99 unsigned int is_data:1;
100};
101
102struct btrfs_delayed_tree_ref {
103 struct btrfs_delayed_ref_node node;
104 u64 root;
105 u64 parent;
106 int level;
107};
108
109struct btrfs_delayed_data_ref {
110 struct btrfs_delayed_ref_node node;
111 u64 root;
112 u64 parent;
113 u64 objectid;
114 u64 offset;
115};
116
117struct 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
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
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;
140
141 u64 run_delayed_start;
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;
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;
162};
163
164static 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
173int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
174 struct btrfs_trans_handle *trans,
175 u64 bytenr, u64 num_bytes, u64 parent,
176 u64 ref_root, int level, int action,
177 struct btrfs_delayed_extent_op *extent_op,
178 int for_cow);
179int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
180 struct btrfs_trans_handle *trans,
181 u64 bytenr, u64 num_bytes,
182 u64 parent, u64 ref_root,
183 u64 owner, u64 offset, int action,
184 struct btrfs_delayed_extent_op *extent_op,
185 int for_cow);
186int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
187 struct btrfs_trans_handle *trans,
188 u64 bytenr, u64 num_bytes,
189 struct btrfs_delayed_extent_op *extent_op);
190
191struct btrfs_delayed_ref_head *
192btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
193int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
194 struct btrfs_delayed_ref_head *head);
195int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
196 struct list_head *cluster, u64 search_start);
197
198static inline u64 inc_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs)
199{
200 assert_spin_locked(&delayed_refs->lock);
201 ++delayed_refs->seq;
202 return delayed_refs->seq;
203}
204
205static inline void
206btrfs_get_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
207 struct seq_list *elem)
208{
209 assert_spin_locked(&delayed_refs->lock);
210 elem->seq = delayed_refs->seq;
211 list_add_tail(&elem->list, &delayed_refs->seq_head);
212}
213
214static inline void
215btrfs_put_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
216 struct seq_list *elem)
217{
218 spin_lock(&delayed_refs->lock);
219 list_del(&elem->list);
220 wake_up(&delayed_refs->seq_wait);
221 spin_unlock(&delayed_refs->lock);
222}
223
224int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
225 u64 seq);
226
227/*
228 * a node might live in a head or a regular ref, this lets you
229 * test for the proper type to use.
230 */
231static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
232{
233 return node->is_head;
234}
235
236/*
237 * helper functions to cast a node into its container
238 */
239static inline struct btrfs_delayed_tree_ref *
240btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
241{
242 WARN_ON(btrfs_delayed_ref_is_head(node));
243 return container_of(node, struct btrfs_delayed_tree_ref, node);
244}
245
246static inline struct btrfs_delayed_data_ref *
247btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
248{
249 WARN_ON(btrfs_delayed_ref_is_head(node));
250 return container_of(node, struct btrfs_delayed_data_ref, node);
251}
252
253static inline struct btrfs_delayed_ref_head *
254btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
255{
256 WARN_ON(!btrfs_delayed_ref_is_head(node));
257 return container_of(node, struct btrfs_delayed_ref_head, node);
258}
259#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
27/*
28 * XXX: Qu: I really hate the design that ref_head and tree/data ref shares the
29 * same ref_node structure.
30 * Ref_head is in a higher logic level than tree/data ref, and duplicated
31 * bytenr/num_bytes in ref_node is really a waste or memory, they should be
32 * referred from ref_head.
33 * This gets more disgusting after we use list to store tree/data ref in
34 * ref_head. Must clean this mess up later.
35 */
36struct btrfs_delayed_ref_node {
37 /*
38 * ref_head use rb tree, stored in ref_root->href.
39 * indexed by bytenr
40 */
41 struct rb_node rb_node;
42
43 /*data/tree ref use list, stored in ref_head->ref_list. */
44 struct list_head list;
45
46 /* the starting bytenr of the extent */
47 u64 bytenr;
48
49 /* the size of the extent */
50 u64 num_bytes;
51
52 /* seq number to keep track of insertion order */
53 u64 seq;
54
55 /* ref count on this data structure */
56 atomic_t refs;
57
58 /*
59 * how many refs is this entry adding or deleting. For
60 * head refs, this may be a negative number because it is keeping
61 * track of the total mods done to the reference count.
62 * For individual refs, this will always be a positive number
63 *
64 * It may be more than one, since it is possible for a single
65 * parent to have more than one ref on an extent
66 */
67 int ref_mod;
68
69 unsigned int action:8;
70 unsigned int type:8;
71 /* is this node still in the rbtree? */
72 unsigned int is_head:1;
73 unsigned int in_tree:1;
74};
75
76struct btrfs_delayed_extent_op {
77 struct btrfs_disk_key key;
78 u8 level;
79 bool update_key;
80 bool update_flags;
81 bool is_data;
82 u64 flags_to_set;
83};
84
85/*
86 * the head refs are used to hold a lock on a given extent, which allows us
87 * to make sure that only one process is running the delayed refs
88 * at a time for a single extent. They also store the sum of all the
89 * reference count modifications we've queued up.
90 */
91struct btrfs_delayed_ref_head {
92 struct btrfs_delayed_ref_node node;
93
94 /*
95 * the mutex is held while running the refs, and it is also
96 * held when checking the sum of reference modifications.
97 */
98 struct mutex mutex;
99
100 spinlock_t lock;
101 struct list_head ref_list;
102
103 struct rb_node href_node;
104
105 struct btrfs_delayed_extent_op *extent_op;
106
107 /*
108 * This is used to track the final ref_mod from all the refs associated
109 * with this head ref, this is not adjusted as delayed refs are run,
110 * this is meant to track if we need to do the csum accounting or not.
111 */
112 int total_ref_mod;
113
114 /*
115 * For qgroup reserved space freeing.
116 *
117 * ref_root and reserved will be recorded after
118 * BTRFS_ADD_DELAYED_EXTENT is called.
119 * And will be used to free reserved qgroup space at
120 * run_delayed_refs() time.
121 */
122 u64 qgroup_ref_root;
123 u64 qgroup_reserved;
124
125 /*
126 * when a new extent is allocated, it is just reserved in memory
127 * The actual extent isn't inserted into the extent allocation tree
128 * until the delayed ref is processed. must_insert_reserved is
129 * used to flag a delayed ref so the accounting can be updated
130 * when a full insert is done.
131 *
132 * It is possible the extent will be freed before it is ever
133 * inserted into the extent allocation tree. In this case
134 * we need to update the in ram accounting to properly reflect
135 * the free has happened.
136 */
137 unsigned int must_insert_reserved:1;
138 unsigned int is_data:1;
139 unsigned int processing:1;
140};
141
142struct btrfs_delayed_tree_ref {
143 struct btrfs_delayed_ref_node node;
144 u64 root;
145 u64 parent;
146 int level;
147};
148
149struct btrfs_delayed_data_ref {
150 struct btrfs_delayed_ref_node node;
151 u64 root;
152 u64 parent;
153 u64 objectid;
154 u64 offset;
155};
156
157struct btrfs_delayed_ref_root {
158 /* head ref rbtree */
159 struct rb_root href_root;
160
161 /* dirty extent records */
162 struct rb_root dirty_extent_root;
163
164 /* this spin lock protects the rbtree and the entries inside */
165 spinlock_t lock;
166
167 /* how many delayed ref updates we've queued, used by the
168 * throttling code
169 */
170 atomic_t num_entries;
171
172 /* total number of head nodes in tree */
173 unsigned long num_heads;
174
175 /* total number of head nodes ready for processing */
176 unsigned long num_heads_ready;
177
178 u64 pending_csums;
179
180 /*
181 * set when the tree is flushing before a transaction commit,
182 * used by the throttling code to decide if new updates need
183 * to be run right away
184 */
185 int flushing;
186
187 u64 run_delayed_start;
188
189 /*
190 * To make qgroup to skip given root.
191 * This is for snapshot, as btrfs_qgroup_inherit() will manully
192 * modify counters for snapshot and its source, so we should skip
193 * the snapshot in new_root/old_roots or it will get calculated twice
194 */
195 u64 qgroup_to_skip;
196};
197
198extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
199extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
200extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
201extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
202
203int btrfs_delayed_ref_init(void);
204void btrfs_delayed_ref_exit(void);
205
206static inline struct btrfs_delayed_extent_op *
207btrfs_alloc_delayed_extent_op(void)
208{
209 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
210}
211
212static inline void
213btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
214{
215 if (op)
216 kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
217}
218
219static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
220{
221 WARN_ON(atomic_read(&ref->refs) == 0);
222 if (atomic_dec_and_test(&ref->refs)) {
223 WARN_ON(ref->in_tree);
224 switch (ref->type) {
225 case BTRFS_TREE_BLOCK_REF_KEY:
226 case BTRFS_SHARED_BLOCK_REF_KEY:
227 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
228 break;
229 case BTRFS_EXTENT_DATA_REF_KEY:
230 case BTRFS_SHARED_DATA_REF_KEY:
231 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
232 break;
233 case 0:
234 kmem_cache_free(btrfs_delayed_ref_head_cachep, ref);
235 break;
236 default:
237 BUG();
238 }
239 }
240}
241
242int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
243 struct btrfs_trans_handle *trans,
244 u64 bytenr, u64 num_bytes, u64 parent,
245 u64 ref_root, int level, int action,
246 struct btrfs_delayed_extent_op *extent_op);
247int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
248 struct btrfs_trans_handle *trans,
249 u64 bytenr, u64 num_bytes,
250 u64 parent, u64 ref_root,
251 u64 owner, u64 offset, u64 reserved, int action,
252 struct btrfs_delayed_extent_op *extent_op);
253int btrfs_add_delayed_qgroup_reserve(struct btrfs_fs_info *fs_info,
254 struct btrfs_trans_handle *trans,
255 u64 ref_root, u64 bytenr, u64 num_bytes);
256int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
257 struct btrfs_trans_handle *trans,
258 u64 bytenr, u64 num_bytes,
259 struct btrfs_delayed_extent_op *extent_op);
260void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
261 struct btrfs_fs_info *fs_info,
262 struct btrfs_delayed_ref_root *delayed_refs,
263 struct btrfs_delayed_ref_head *head);
264
265struct btrfs_delayed_ref_head *
266btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
267int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
268 struct btrfs_delayed_ref_head *head);
269static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
270{
271 mutex_unlock(&head->mutex);
272}
273
274
275struct btrfs_delayed_ref_head *
276btrfs_select_ref_head(struct btrfs_trans_handle *trans);
277
278int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
279 struct btrfs_delayed_ref_root *delayed_refs,
280 u64 seq);
281
282/*
283 * a node might live in a head or a regular ref, this lets you
284 * test for the proper type to use.
285 */
286static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
287{
288 return node->is_head;
289}
290
291/*
292 * helper functions to cast a node into its container
293 */
294static inline struct btrfs_delayed_tree_ref *
295btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
296{
297 WARN_ON(btrfs_delayed_ref_is_head(node));
298 return container_of(node, struct btrfs_delayed_tree_ref, node);
299}
300
301static inline struct btrfs_delayed_data_ref *
302btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
303{
304 WARN_ON(btrfs_delayed_ref_is_head(node));
305 return container_of(node, struct btrfs_delayed_data_ref, node);
306}
307
308static inline struct btrfs_delayed_ref_head *
309btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
310{
311 WARN_ON(!btrfs_delayed_ref_is_head(node));
312 return container_of(node, struct btrfs_delayed_ref_head, node);
313}
314#endif