2 * Copyright (C) 2008 Oracle. All rights reserved.
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.
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.
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.
18 #ifndef __DELAYED_REF__
19 #define __DELAYED_REF__
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 */
27 struct btrfs_delayed_ref_node
{
28 struct rb_node rb_node
;
30 /* the starting bytenr of the extent */
33 /* the size of the extent */
36 /* seq number to keep track of insertion order */
39 /* ref count on this data structure */
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
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
53 unsigned int action
:8;
55 /* is this node still in the rbtree? */
56 unsigned int is_head
:1;
57 unsigned int in_tree
:1;
60 struct btrfs_delayed_extent_op
{
61 struct btrfs_disk_key key
;
63 unsigned int update_key
:1;
64 unsigned int update_flags
:1;
65 unsigned int is_data
:1;
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.
74 struct btrfs_delayed_ref_head
{
75 struct btrfs_delayed_ref_node node
;
78 * the mutex is held while running the refs, and it is also
79 * held when checking the sum of reference modifications.
83 struct list_head cluster
;
85 struct btrfs_delayed_extent_op
*extent_op
;
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.
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.
98 unsigned int must_insert_reserved
:1;
99 unsigned int is_data
:1;
102 struct btrfs_delayed_tree_ref
{
103 struct btrfs_delayed_ref_node node
;
109 struct btrfs_delayed_data_ref
{
110 struct btrfs_delayed_ref_node node
;
117 struct btrfs_delayed_ref_root
{
120 /* this spin lock protects the rbtree and the entries inside */
123 /* how many delayed ref updates we've queued, used by the
126 unsigned long num_entries
;
128 /* total number of head nodes in tree */
129 unsigned long num_heads
;
131 /* total number of head nodes ready for processing */
132 unsigned long num_heads_ready
;
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
141 u64 run_delayed_start
;
144 * seq number of delayed refs. We need to know if a backref was being
145 * added before the currently processed ref or afterwards.
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.
155 struct list_head seq_head
;
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.
161 wait_queue_head_t seq_wait
;
164 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node
*ref
)
166 WARN_ON(atomic_read(&ref
->refs
) == 0);
167 if (atomic_dec_and_test(&ref
->refs
)) {
168 WARN_ON(ref
->in_tree
);
173 int 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
,
179 int 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
,
186 int 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
);
191 struct btrfs_delayed_ref_head
*
192 btrfs_find_delayed_ref_head(struct btrfs_trans_handle
*trans
, u64 bytenr
);
193 int btrfs_delayed_ref_lock(struct btrfs_trans_handle
*trans
,
194 struct btrfs_delayed_ref_head
*head
);
195 int btrfs_find_ref_cluster(struct btrfs_trans_handle
*trans
,
196 struct list_head
*cluster
, u64 search_start
);
198 static inline u64
inc_delayed_seq(struct btrfs_delayed_ref_root
*delayed_refs
)
200 assert_spin_locked(&delayed_refs
->lock
);
202 return delayed_refs
->seq
;
206 btrfs_get_delayed_seq(struct btrfs_delayed_ref_root
*delayed_refs
,
207 struct seq_list
*elem
)
209 assert_spin_locked(&delayed_refs
->lock
);
210 elem
->seq
= delayed_refs
->seq
;
211 list_add_tail(&elem
->list
, &delayed_refs
->seq_head
);
215 btrfs_put_delayed_seq(struct btrfs_delayed_ref_root
*delayed_refs
,
216 struct seq_list
*elem
)
218 spin_lock(&delayed_refs
->lock
);
219 list_del(&elem
->list
);
220 wake_up(&delayed_refs
->seq_wait
);
221 spin_unlock(&delayed_refs
->lock
);
224 int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root
*delayed_refs
,
228 * a node might live in a head or a regular ref, this lets you
229 * test for the proper type to use.
231 static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node
*node
)
233 return node
->is_head
;
237 * helper functions to cast a node into its container
239 static inline struct btrfs_delayed_tree_ref
*
240 btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node
*node
)
242 WARN_ON(btrfs_delayed_ref_is_head(node
));
243 return container_of(node
, struct btrfs_delayed_tree_ref
, node
);
246 static inline struct btrfs_delayed_data_ref
*
247 btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node
*node
)
249 WARN_ON(btrfs_delayed_ref_is_head(node
));
250 return container_of(node
, struct btrfs_delayed_data_ref
, node
);
253 static inline struct btrfs_delayed_ref_head
*
254 btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node
*node
)
256 WARN_ON(!btrfs_delayed_ref_is_head(node
));
257 return container_of(node
, struct btrfs_delayed_ref_head
, node
);