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	unsigned int no_quota:1;
56	/* is this node still in the rbtree? */
57	unsigned int is_head:1;
58	unsigned int in_tree:1;
59};
60
61struct btrfs_delayed_extent_op {
62	struct btrfs_disk_key key;
63	u64 flags_to_set;
64	int level;
65	unsigned int update_key:1;
66	unsigned int update_flags:1;
67	unsigned int is_data:1;
68};
69
70/*
71 * the head refs are used to hold a lock on a given extent, which allows us
72 * to make sure that only one process is running the delayed refs
73 * at a time for a single extent.  They also store the sum of all the
74 * reference count modifications we've queued up.
75 */
76struct btrfs_delayed_ref_head {
77	struct btrfs_delayed_ref_node node;
78
79	/*
80	 * the mutex is held while running the refs, and it is also
81	 * held when checking the sum of reference modifications.
82	 */
83	struct mutex mutex;
84
85	spinlock_t lock;
86	struct rb_root ref_root;
87
88	struct rb_node href_node;
89
90	struct btrfs_delayed_extent_op *extent_op;
91	/*
92	 * when a new extent is allocated, it is just reserved in memory
93	 * The actual extent isn't inserted into the extent allocation tree
94	 * until the delayed ref is processed.  must_insert_reserved is
95	 * used to flag a delayed ref so the accounting can be updated
96	 * when a full insert is done.
97	 *
98	 * It is possible the extent will be freed before it is ever
99	 * inserted into the extent allocation tree.  In this case
100	 * we need to update the in ram accounting to properly reflect
101	 * the free has happened.
102	 */
103	unsigned int must_insert_reserved:1;
104	unsigned int is_data:1;
105	unsigned int processing:1;
106};
107
108struct btrfs_delayed_tree_ref {
109	struct btrfs_delayed_ref_node node;
110	u64 root;
111	u64 parent;
112	int level;
113};
114
115struct btrfs_delayed_data_ref {
116	struct btrfs_delayed_ref_node node;
117	u64 root;
118	u64 parent;
119	u64 objectid;
120	u64 offset;
121};
122
123struct btrfs_delayed_ref_root {
124	/* head ref rbtree */
125	struct rb_root href_root;
126
127	/* this spin lock protects the rbtree and the entries inside */
128	spinlock_t lock;
129
130	/* how many delayed ref updates we've queued, used by the
131	 * throttling code
132	 */
133	atomic_t num_entries;
134
135	/* total number of head nodes in tree */
136	unsigned long num_heads;
137
138	/* total number of head nodes ready for processing */
139	unsigned long num_heads_ready;
140
141	/*
142	 * set when the tree is flushing before a transaction commit,
143	 * used by the throttling code to decide if new updates need
144	 * to be run right away
145	 */
146	int flushing;
147
148	u64 run_delayed_start;
149};
150
151extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
152extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
153extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
154extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
155
156int btrfs_delayed_ref_init(void);
157void btrfs_delayed_ref_exit(void);
158
159static inline struct btrfs_delayed_extent_op *
160btrfs_alloc_delayed_extent_op(void)
161{
162	return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
163}
164
165static inline void
166btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
167{
168	if (op)
169		kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
170}
171
172static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
173{
174	WARN_ON(atomic_read(&ref->refs) == 0);
175	if (atomic_dec_and_test(&ref->refs)) {
176		WARN_ON(ref->in_tree);
177		switch (ref->type) {
178		case BTRFS_TREE_BLOCK_REF_KEY:
179		case BTRFS_SHARED_BLOCK_REF_KEY:
180			kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
181			break;
182		case BTRFS_EXTENT_DATA_REF_KEY:
183		case BTRFS_SHARED_DATA_REF_KEY:
184			kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
185			break;
186		case 0:
187			kmem_cache_free(btrfs_delayed_ref_head_cachep, ref);
188			break;
189		default:
190			BUG();
191		}
192	}
193}
194
195int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
196			       struct btrfs_trans_handle *trans,
197			       u64 bytenr, u64 num_bytes, u64 parent,
198			       u64 ref_root, int level, int action,
199			       struct btrfs_delayed_extent_op *extent_op,
200			       int no_quota);
201int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
202			       struct btrfs_trans_handle *trans,
203			       u64 bytenr, u64 num_bytes,
204			       u64 parent, u64 ref_root,
205			       u64 owner, u64 offset, int action,
206			       struct btrfs_delayed_extent_op *extent_op,
207			       int no_quota);
208int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
209				struct btrfs_trans_handle *trans,
210				u64 bytenr, u64 num_bytes,
211				struct btrfs_delayed_extent_op *extent_op);
212void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
213			      struct btrfs_fs_info *fs_info,
214			      struct btrfs_delayed_ref_root *delayed_refs,
215			      struct btrfs_delayed_ref_head *head);
216
217struct btrfs_delayed_ref_head *
218btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
219int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
220			   struct btrfs_delayed_ref_head *head);
221static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
222{
223	mutex_unlock(&head->mutex);
224}
225
226
227struct btrfs_delayed_ref_head *
228btrfs_select_ref_head(struct btrfs_trans_handle *trans);
229
230int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
231			    struct btrfs_delayed_ref_root *delayed_refs,
232			    u64 seq);
233
234/*
235 * a node might live in a head or a regular ref, this lets you
236 * test for the proper type to use.
237 */
238static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
239{
240	return node->is_head;
241}
242
243/*
244 * helper functions to cast a node into its container
245 */
246static inline struct btrfs_delayed_tree_ref *
247btrfs_delayed_node_to_tree_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_tree_ref, node);
251}
252
253static inline struct btrfs_delayed_data_ref *
254btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
255{
256	WARN_ON(btrfs_delayed_ref_is_head(node));
257	return container_of(node, struct btrfs_delayed_data_ref, node);
258}
259
260static inline struct btrfs_delayed_ref_head *
261btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
262{
263	WARN_ON(!btrfs_delayed_ref_is_head(node));
264	return container_of(node, struct btrfs_delayed_ref_head, node);
265}
266#endif
267