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_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 */
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.
36 struct btrfs_delayed_ref_node
{
38 * ref_head use rb tree, stored in ref_root->href.
41 struct rb_node rb_node
;
43 /*data/tree ref use list, stored in ref_head->ref_list. */
44 struct list_head list
;
46 /* the starting bytenr of the extent */
49 /* the size of the extent */
52 /* seq number to keep track of insertion order */
55 /* ref count on this data structure */
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
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
69 unsigned int action
:8;
71 /* is this node still in the rbtree? */
72 unsigned int is_head
:1;
73 unsigned int in_tree
:1;
76 struct btrfs_delayed_extent_op
{
77 struct btrfs_disk_key key
;
80 unsigned int update_key
:1;
81 unsigned int update_flags
:1;
82 unsigned int is_data
:1;
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.
91 struct btrfs_delayed_ref_head
{
92 struct btrfs_delayed_ref_node node
;
95 * the mutex is held while running the refs, and it is also
96 * held when checking the sum of reference modifications.
101 struct list_head ref_list
;
103 struct rb_node href_node
;
105 struct btrfs_delayed_extent_op
*extent_op
;
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.
115 * For qgroup reserved space freeing.
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.
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.
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.
137 unsigned int must_insert_reserved
:1;
138 unsigned int is_data
:1;
139 unsigned int processing
:1;
142 struct btrfs_delayed_tree_ref
{
143 struct btrfs_delayed_ref_node node
;
149 struct btrfs_delayed_data_ref
{
150 struct btrfs_delayed_ref_node node
;
157 struct btrfs_delayed_ref_root
{
158 /* head ref rbtree */
159 struct rb_root href_root
;
161 /* dirty extent records */
162 struct rb_root dirty_extent_root
;
164 /* this spin lock protects the rbtree and the entries inside */
167 /* how many delayed ref updates we've queued, used by the
170 atomic_t num_entries
;
172 /* total number of head nodes in tree */
173 unsigned long num_heads
;
175 /* total number of head nodes ready for processing */
176 unsigned long num_heads_ready
;
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
187 u64 run_delayed_start
;
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
198 extern struct kmem_cache
*btrfs_delayed_ref_head_cachep
;
199 extern struct kmem_cache
*btrfs_delayed_tree_ref_cachep
;
200 extern struct kmem_cache
*btrfs_delayed_data_ref_cachep
;
201 extern struct kmem_cache
*btrfs_delayed_extent_op_cachep
;
203 int btrfs_delayed_ref_init(void);
204 void btrfs_delayed_ref_exit(void);
206 static inline struct btrfs_delayed_extent_op
*
207 btrfs_alloc_delayed_extent_op(void)
209 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep
, GFP_NOFS
);
213 btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op
*op
)
216 kmem_cache_free(btrfs_delayed_extent_op_cachep
, op
);
219 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node
*ref
)
221 WARN_ON(atomic_read(&ref
->refs
) == 0);
222 if (atomic_dec_and_test(&ref
->refs
)) {
223 WARN_ON(ref
->in_tree
);
225 case BTRFS_TREE_BLOCK_REF_KEY
:
226 case BTRFS_SHARED_BLOCK_REF_KEY
:
227 kmem_cache_free(btrfs_delayed_tree_ref_cachep
, ref
);
229 case BTRFS_EXTENT_DATA_REF_KEY
:
230 case BTRFS_SHARED_DATA_REF_KEY
:
231 kmem_cache_free(btrfs_delayed_data_ref_cachep
, ref
);
234 kmem_cache_free(btrfs_delayed_ref_head_cachep
, ref
);
242 int 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
);
247 int 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
, int action
,
252 struct btrfs_delayed_extent_op
*extent_op
);
253 int 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
);
256 int 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
);
260 void 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
);
265 struct btrfs_delayed_ref_head
*
266 btrfs_find_delayed_ref_head(struct btrfs_trans_handle
*trans
, u64 bytenr
);
267 int btrfs_delayed_ref_lock(struct btrfs_trans_handle
*trans
,
268 struct btrfs_delayed_ref_head
*head
);
269 static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head
*head
)
271 mutex_unlock(&head
->mutex
);
275 struct btrfs_delayed_ref_head
*
276 btrfs_select_ref_head(struct btrfs_trans_handle
*trans
);
278 int btrfs_check_delayed_seq(struct btrfs_fs_info
*fs_info
,
279 struct btrfs_delayed_ref_root
*delayed_refs
,
283 * a node might live in a head or a regular ref, this lets you
284 * test for the proper type to use.
286 static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node
*node
)
288 return node
->is_head
;
292 * helper functions to cast a node into its container
294 static inline struct btrfs_delayed_tree_ref
*
295 btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node
*node
)
297 WARN_ON(btrfs_delayed_ref_is_head(node
));
298 return container_of(node
, struct btrfs_delayed_tree_ref
, node
);
301 static inline struct btrfs_delayed_data_ref
*
302 btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node
*node
)
304 WARN_ON(btrfs_delayed_ref_is_head(node
));
305 return container_of(node
, struct btrfs_delayed_data_ref
, node
);
308 static inline struct btrfs_delayed_ref_head
*
309 btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node
*node
)
311 WARN_ON(!btrfs_delayed_ref_is_head(node
));
312 return container_of(node
, struct btrfs_delayed_ref_head
, node
);