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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_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 : : 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 : : /* 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 : :
60 : : struct 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 : : */
75 : : struct 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 : : struct list_head cluster;
85 : :
86 : : struct btrfs_delayed_extent_op *extent_op;
87 : : /*
88 : : * when a new extent is allocated, it is just reserved in memory
89 : : * The actual extent isn't inserted into the extent allocation tree
90 : : * until the delayed ref is processed. must_insert_reserved is
91 : : * used to flag a delayed ref so the accounting can be updated
92 : : * when a full insert is done.
93 : : *
94 : : * It is possible the extent will be freed before it is ever
95 : : * inserted into the extent allocation tree. In this case
96 : : * we need to update the in ram accounting to properly reflect
97 : : * the free has happened.
98 : : */
99 : : unsigned int must_insert_reserved:1;
100 : : unsigned int is_data:1;
101 : : };
102 : :
103 : : struct btrfs_delayed_tree_ref {
104 : : struct btrfs_delayed_ref_node node;
105 : : u64 root;
106 : : u64 parent;
107 : : int level;
108 : : };
109 : :
110 : : struct btrfs_delayed_data_ref {
111 : : struct btrfs_delayed_ref_node node;
112 : : u64 root;
113 : : u64 parent;
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 : : * bumped when someone is making progress on the delayed
137 : : * refs, so that other procs know they are just adding to
138 : : * contention intead of helping
139 : : */
140 : : atomic_t procs_running_refs;
141 : : atomic_t ref_seq;
142 : : wait_queue_head_t wait;
143 : :
144 : : /*
145 : : * set when the tree is flushing before a transaction commit,
146 : : * used by the throttling code to decide if new updates need
147 : : * to be run right away
148 : : */
149 : : int flushing;
150 : :
151 : : u64 run_delayed_start;
152 : : };
153 : :
154 : : extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
155 : : extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
156 : : extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
157 : : extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
158 : :
159 : : int btrfs_delayed_ref_init(void);
160 : : void btrfs_delayed_ref_exit(void);
161 : :
162 : : static inline struct btrfs_delayed_extent_op *
163 : : btrfs_alloc_delayed_extent_op(void)
164 : : {
165 : 0 : return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
166 : : }
167 : :
168 : : static inline void
169 : : btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
170 : : {
171 [ # # ][ # # ]: 0 : if (op)
[ # # # #
# # ]
172 : 0 : kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
173 : : }
174 : :
175 : : static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
176 : : {
177 [ # # ][ # # ]: 0 : WARN_ON(atomic_read(&ref->refs) == 0);
[ # # ][ # # ]
[ # # ][ # # ]
[ # # ]
178 [ # # # # : 0 : if (atomic_dec_and_test(&ref->refs)) {
# # # # #
# # # ]
179 [ # # ][ # # ]: 0 : WARN_ON(ref->in_tree);
[ # # ][ # # ]
[ # # ][ # # ]
180 [ # # # # ]: 0 : switch (ref->type) {
[ # # # # ]
[ # # # # ]
[ # # # # ]
[ # # # # ]
[ # # # # ]
181 : : case BTRFS_TREE_BLOCK_REF_KEY:
182 : : case BTRFS_SHARED_BLOCK_REF_KEY:
183 : 0 : kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
184 : : break;
185 : : case BTRFS_EXTENT_DATA_REF_KEY:
186 : : case BTRFS_SHARED_DATA_REF_KEY:
187 : 0 : kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
188 : : break;
189 : : case 0:
190 : 0 : kmem_cache_free(btrfs_delayed_ref_head_cachep, ref);
191 : : break;
192 : : default:
193 : 0 : BUG();
194 : : }
195 : : }
196 : : }
197 : :
198 : : int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
199 : : struct btrfs_trans_handle *trans,
200 : : u64 bytenr, u64 num_bytes, u64 parent,
201 : : u64 ref_root, int level, int action,
202 : : struct btrfs_delayed_extent_op *extent_op,
203 : : int for_cow);
204 : : int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
205 : : struct btrfs_trans_handle *trans,
206 : : u64 bytenr, u64 num_bytes,
207 : : u64 parent, u64 ref_root,
208 : : u64 owner, u64 offset, int action,
209 : : struct btrfs_delayed_extent_op *extent_op,
210 : : int for_cow);
211 : : int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
212 : : struct btrfs_trans_handle *trans,
213 : : u64 bytenr, u64 num_bytes,
214 : : struct btrfs_delayed_extent_op *extent_op);
215 : : void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
216 : : struct btrfs_fs_info *fs_info,
217 : : struct btrfs_delayed_ref_root *delayed_refs,
218 : : struct btrfs_delayed_ref_head *head);
219 : :
220 : : struct btrfs_delayed_ref_head *
221 : : btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
222 : : int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
223 : : struct btrfs_delayed_ref_head *head);
224 : : static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
225 : : {
226 : 0 : mutex_unlock(&head->mutex);
227 : : }
228 : :
229 : : int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
230 : : struct list_head *cluster, u64 search_start);
231 : : void btrfs_release_ref_cluster(struct list_head *cluster);
232 : :
233 : : int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
234 : : struct btrfs_delayed_ref_root *delayed_refs,
235 : : u64 seq);
236 : :
237 : : /*
238 : : * delayed refs with a ref_seq > 0 must be held back during backref walking.
239 : : * this only applies to items in one of the fs-trees. for_cow items never need
240 : : * to be held back, so they won't get a ref_seq number.
241 : : */
242 : : static inline int need_ref_seq(int for_cow, u64 rootid)
243 : : {
244 [ # # # # ]: 0 : if (for_cow)
[ # # ][ # # ]
245 : : return 0;
246 : :
247 [ # # ][ # # ]: 0 : if (rootid == BTRFS_FS_TREE_OBJECTID)
[ # # ][ # # ]
248 : : return 1;
249 : :
250 [ # # ][ # # ]: 0 : if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
[ # # ][ # # ]
251 : : return 1;
252 : :
253 : : return 0;
254 : : }
255 : :
256 : : /*
257 : : * a node might live in a head or a regular ref, this lets you
258 : : * test for the proper type to use.
259 : : */
260 : 0 : static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
261 : : {
262 : 0 : return node->is_head;
263 : : }
264 : :
265 : : /*
266 : : * helper functions to cast a node into its container
267 : : */
268 : : static inline struct btrfs_delayed_tree_ref *
269 : : btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
270 : : {
271 [ # # ][ # # ]: 0 : WARN_ON(btrfs_delayed_ref_is_head(node));
[ # # ]
272 : : return container_of(node, struct btrfs_delayed_tree_ref, node);
273 : : }
274 : :
275 : : static inline struct btrfs_delayed_data_ref *
276 : : btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
277 : : {
278 [ # # ][ # # ]: 0 : WARN_ON(btrfs_delayed_ref_is_head(node));
[ # # ]
279 : : return container_of(node, struct btrfs_delayed_data_ref, node);
280 : : }
281 : :
282 : : static inline struct btrfs_delayed_ref_head *
283 : : btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
284 : : {
285 [ # # ][ # # ]: 0 : WARN_ON(!btrfs_delayed_ref_is_head(node));
[ # # ][ # # ]
[ # # ]
286 : : return container_of(node, struct btrfs_delayed_ref_head, node);
287 : : }
288 : : #endif
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