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	/*
93	 * This is used to track the final ref_mod from all the refs associated
94	 * with this head ref, this is not adjusted as delayed refs are run,
95	 * this is meant to track if we need to do the csum accounting or not.
96	 */
97	int total_ref_mod;
98
99	/*
100	 * when a new extent is allocated, it is just reserved in memory
101	 * The actual extent isn't inserted into the extent allocation tree
102	 * until the delayed ref is processed.  must_insert_reserved is
103	 * used to flag a delayed ref so the accounting can be updated
104	 * when a full insert is done.
105	 *
106	 * It is possible the extent will be freed before it is ever
107	 * inserted into the extent allocation tree.  In this case
108	 * we need to update the in ram accounting to properly reflect
109	 * the free has happened.
110	 */
111	unsigned int must_insert_reserved:1;
112	unsigned int is_data:1;
113	unsigned int processing:1;
114};
115
116struct btrfs_delayed_tree_ref {
117	struct btrfs_delayed_ref_node node;
118	u64 root;
119	u64 parent;
120	int level;
121};
122
123struct btrfs_delayed_data_ref {
124	struct btrfs_delayed_ref_node node;
125	u64 root;
126	u64 parent;
127	u64 objectid;
128	u64 offset;
129};
130
131struct btrfs_delayed_ref_root {
132	/* head ref rbtree */
133	struct rb_root href_root;
134
135	/* this spin lock protects the rbtree and the entries inside */
136	spinlock_t lock;
137
138	/* how many delayed ref updates we've queued, used by the
139	 * throttling code
140	 */
141	atomic_t num_entries;
142
143	/* total number of head nodes in tree */
144	unsigned long num_heads;
145
146	/* total number of head nodes ready for processing */
147	unsigned long num_heads_ready;
148
149	u64 pending_csums;
150
151	/*
152	 * set when the tree is flushing before a transaction commit,
153	 * used by the throttling code to decide if new updates need
154	 * to be run right away
155	 */
156	int flushing;
157
158	u64 run_delayed_start;
159};
160
161extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
162extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
163extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
164extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
165
166int btrfs_delayed_ref_init(void);
167void btrfs_delayed_ref_exit(void);
168
169static inline struct btrfs_delayed_extent_op *
170btrfs_alloc_delayed_extent_op(void)
171{
172	return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
173}
174
175static inline void
176btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
177{
178	if (op)
179		kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
180}
181
182static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
183{
184	WARN_ON(atomic_read(&ref->refs) == 0);
185	if (atomic_dec_and_test(&ref->refs)) {
186		WARN_ON(ref->in_tree);
187		switch (ref->type) {
188		case BTRFS_TREE_BLOCK_REF_KEY:
189		case BTRFS_SHARED_BLOCK_REF_KEY:
190			kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
191			break;
192		case BTRFS_EXTENT_DATA_REF_KEY:
193		case BTRFS_SHARED_DATA_REF_KEY:
194			kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
195			break;
196		case 0:
197			kmem_cache_free(btrfs_delayed_ref_head_cachep, ref);
198			break;
199		default:
200			BUG();
201		}
202	}
203}
204
205int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
206			       struct btrfs_trans_handle *trans,
207			       u64 bytenr, u64 num_bytes, u64 parent,
208			       u64 ref_root, int level, int action,
209			       struct btrfs_delayed_extent_op *extent_op,
210			       int no_quota);
211int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
212			       struct btrfs_trans_handle *trans,
213			       u64 bytenr, u64 num_bytes,
214			       u64 parent, u64 ref_root,
215			       u64 owner, u64 offset, int action,
216			       struct btrfs_delayed_extent_op *extent_op,
217			       int no_quota);
218int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
219				struct btrfs_trans_handle *trans,
220				u64 bytenr, u64 num_bytes,
221				struct btrfs_delayed_extent_op *extent_op);
222void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
223			      struct btrfs_fs_info *fs_info,
224			      struct btrfs_delayed_ref_root *delayed_refs,
225			      struct btrfs_delayed_ref_head *head);
226
227struct btrfs_delayed_ref_head *
228btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
229int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
230			   struct btrfs_delayed_ref_head *head);
231static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
232{
233	mutex_unlock(&head->mutex);
234}
235
236
237struct btrfs_delayed_ref_head *
238btrfs_select_ref_head(struct btrfs_trans_handle *trans);
239
240int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
241			    struct btrfs_delayed_ref_root *delayed_refs,
242			    u64 seq);
243
244/*
245 * a node might live in a head or a regular ref, this lets you
246 * test for the proper type to use.
247 */
248static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
249{
250	return node->is_head;
251}
252
253/*
254 * helper functions to cast a node into its container
255 */
256static inline struct btrfs_delayed_tree_ref *
257btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
258{
259	WARN_ON(btrfs_delayed_ref_is_head(node));
260	return container_of(node, struct btrfs_delayed_tree_ref, node);
261}
262
263static inline struct btrfs_delayed_data_ref *
264btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
265{
266	WARN_ON(btrfs_delayed_ref_is_head(node));
267	return container_of(node, struct btrfs_delayed_data_ref, node);
268}
269
270static inline struct btrfs_delayed_ref_head *
271btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
272{
273	WARN_ON(!btrfs_delayed_ref_is_head(node));
274	return container_of(node, struct btrfs_delayed_ref_head, node);
275}
276#endif
277