1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Copyright (C) 2008 Oracle. All rights reserved.
6 #ifndef BTRFS_DELAYED_REF_H
7 #define BTRFS_DELAYED_REF_H
9 #include <linux/refcount.h>
11 /* these are the possible values of struct btrfs_delayed_ref_node->action */
12 #define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */
13 #define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */
14 #define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */
15 #define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */
17 struct btrfs_delayed_ref_node {
18 struct rb_node ref_node;
20 * If action is BTRFS_ADD_DELAYED_REF, also link this node to
21 * ref_head->ref_add_list, then we do not need to iterate the
22 * whole ref_head->ref_list to find BTRFS_ADD_DELAYED_REF nodes.
24 struct list_head add_list;
26 /* the starting bytenr of the extent */
29 /* the size of the extent */
32 /* seq number to keep track of insertion order */
35 /* ref count on this data structure */
39 * how many refs is this entry adding or deleting. For
40 * head refs, this may be a negative number because it is keeping
41 * track of the total mods done to the reference count.
42 * For individual refs, this will always be a positive number
44 * It may be more than one, since it is possible for a single
45 * parent to have more than one ref on an extent
49 unsigned int action:8;
51 /* is this node still in the rbtree? */
52 unsigned int is_head:1;
53 unsigned int in_tree:1;
56 struct btrfs_delayed_extent_op {
57 struct btrfs_disk_key key;
66 * the head refs are used to hold a lock on a given extent, which allows us
67 * to make sure that only one process is running the delayed refs
68 * at a time for a single extent. They also store the sum of all the
69 * reference count modifications we've queued up.
71 struct btrfs_delayed_ref_head {
76 * the mutex is held while running the refs, and it is also
77 * held when checking the sum of reference modifications.
82 struct rb_root_cached ref_tree;
83 /* accumulate add BTRFS_ADD_DELAYED_REF nodes to this ref_add_list. */
84 struct list_head ref_add_list;
86 struct rb_node href_node;
88 struct btrfs_delayed_extent_op *extent_op;
91 * This is used to track the final ref_mod from all the refs associated
92 * with this head ref, this is not adjusted as delayed refs are run,
93 * this is meant to track if we need to do the csum accounting or not.
98 * This is the current outstanding mod references for this bytenr. This
99 * is used with lookup_extent_info to get an accurate reference count
100 * for a bytenr, so it is adjusted as delayed refs are run so that any
101 * on disk reference count + ref_mod is accurate.
106 * when a new extent is allocated, it is just reserved in memory
107 * The actual extent isn't inserted into the extent allocation tree
108 * until the delayed ref is processed. must_insert_reserved is
109 * used to flag a delayed ref so the accounting can be updated
110 * when a full insert is done.
112 * It is possible the extent will be freed before it is ever
113 * inserted into the extent allocation tree. In this case
114 * we need to update the in ram accounting to properly reflect
115 * the free has happened.
117 unsigned int must_insert_reserved:1;
118 unsigned int is_data:1;
119 unsigned int is_system:1;
120 unsigned int processing:1;
123 struct btrfs_delayed_tree_ref {
124 struct btrfs_delayed_ref_node node;
130 struct btrfs_delayed_data_ref {
131 struct btrfs_delayed_ref_node node;
138 struct btrfs_delayed_ref_root {
139 /* head ref rbtree */
140 struct rb_root_cached href_root;
142 /* dirty extent records */
143 struct rb_root dirty_extent_root;
145 /* this spin lock protects the rbtree and the entries inside */
148 /* how many delayed ref updates we've queued, used by the
151 atomic_t num_entries;
153 /* total number of head nodes in tree */
154 unsigned long num_heads;
156 /* total number of head nodes ready for processing */
157 unsigned long num_heads_ready;
162 * set when the tree is flushing before a transaction commit,
163 * used by the throttling code to decide if new updates need
164 * to be run right away
168 u64 run_delayed_start;
171 * To make qgroup to skip given root.
172 * This is for snapshot, as btrfs_qgroup_inherit() will manually
173 * modify counters for snapshot and its source, so we should skip
174 * the snapshot in new_root/old_roots or it will get calculated twice
179 extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
180 extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
181 extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
182 extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
184 int __init btrfs_delayed_ref_init(void);
185 void __cold btrfs_delayed_ref_exit(void);
187 static inline struct btrfs_delayed_extent_op *
188 btrfs_alloc_delayed_extent_op(void)
190 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
194 btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
197 kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
200 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
202 WARN_ON(refcount_read(&ref->refs) == 0);
203 if (refcount_dec_and_test(&ref->refs)) {
204 WARN_ON(ref->in_tree);
206 case BTRFS_TREE_BLOCK_REF_KEY:
207 case BTRFS_SHARED_BLOCK_REF_KEY:
208 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
210 case BTRFS_EXTENT_DATA_REF_KEY:
211 case BTRFS_SHARED_DATA_REF_KEY:
212 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
220 static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *head)
222 if (refcount_dec_and_test(&head->refs))
223 kmem_cache_free(btrfs_delayed_ref_head_cachep, head);
226 int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
227 u64 bytenr, u64 num_bytes, u64 parent,
228 u64 ref_root, int level, int action,
229 struct btrfs_delayed_extent_op *extent_op,
230 int *old_ref_mod, int *new_ref_mod);
231 int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
232 u64 bytenr, u64 num_bytes,
233 u64 parent, u64 ref_root,
234 u64 owner, u64 offset, u64 reserved, int action,
235 int *old_ref_mod, int *new_ref_mod);
236 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
237 struct btrfs_trans_handle *trans,
238 u64 bytenr, u64 num_bytes,
239 struct btrfs_delayed_extent_op *extent_op);
240 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
241 struct btrfs_delayed_ref_root *delayed_refs,
242 struct btrfs_delayed_ref_head *head);
244 struct btrfs_delayed_ref_head *
245 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
247 int btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs,
248 struct btrfs_delayed_ref_head *head);
249 static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
251 mutex_unlock(&head->mutex);
253 void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
254 struct btrfs_delayed_ref_head *head);
256 struct btrfs_delayed_ref_head *btrfs_select_ref_head(
257 struct btrfs_delayed_ref_root *delayed_refs);
259 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq);
262 * helper functions to cast a node into its container
264 static inline struct btrfs_delayed_tree_ref *
265 btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
267 return container_of(node, struct btrfs_delayed_tree_ref, node);
270 static inline struct btrfs_delayed_data_ref *
271 btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
273 return container_of(node, struct btrfs_delayed_data_ref, node);