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 enum btrfs_delayed_ref_flags {
139 /* Indicate that we are flushing delayed refs for the commit */
140 BTRFS_DELAYED_REFS_FLUSHING,
143 struct btrfs_delayed_ref_root {
144 /* head ref rbtree */
145 struct rb_root_cached href_root;
147 /* dirty extent records */
148 struct rb_root dirty_extent_root;
150 /* this spin lock protects the rbtree and the entries inside */
153 /* how many delayed ref updates we've queued, used by the
156 atomic_t num_entries;
158 /* total number of head nodes in tree */
159 unsigned long num_heads;
161 /* total number of head nodes ready for processing */
162 unsigned long num_heads_ready;
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 enum btrfs_ref_type {
186 struct btrfs_data_ref {
187 /* For EXTENT_DATA_REF */
189 /* Root which refers to this data extent */
192 /* Inode which refers to this data extent */
196 * file_offset - extent_offset
198 * file_offset is the key.offset of the EXTENT_DATA key.
199 * extent_offset is btrfs_file_extent_offset() of the EXTENT_DATA data.
204 struct btrfs_tree_ref {
206 * Level of this tree block
208 * Shared for skinny (TREE_BLOCK_REF) and normal tree ref.
213 * Root which refers to this tree block.
215 * For TREE_BLOCK_REF (skinny metadata, either inline or keyed)
219 /* For non-skinny metadata, no special member needed */
223 enum btrfs_ref_type type;
227 * Whether this extent should go through qgroup record.
229 * Normally false, but for certain cases like delayed subtree scan,
230 * setting this flag can hugely reduce qgroup overhead.
235 * Optional. For which root is this modification.
236 * Mostly used for qgroup optimization.
238 * When unset, data/tree ref init code will populate it.
239 * In certain cases, we're modifying reference for a different root.
240 * E.g. COW fs tree blocks for balance.
241 * In that case, tree_ref::root will be fs tree, but we're doing this
242 * for reloc tree, then we should set @real_root to reloc tree.
248 /* Bytenr of the parent tree block */
251 struct btrfs_data_ref data_ref;
252 struct btrfs_tree_ref tree_ref;
256 extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
257 extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
258 extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
259 extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
261 int __init btrfs_delayed_ref_init(void);
262 void __cold btrfs_delayed_ref_exit(void);
264 static inline void btrfs_init_generic_ref(struct btrfs_ref *generic_ref,
265 int action, u64 bytenr, u64 len, u64 parent)
267 generic_ref->action = action;
268 generic_ref->bytenr = bytenr;
269 generic_ref->len = len;
270 generic_ref->parent = parent;
273 static inline void btrfs_init_tree_ref(struct btrfs_ref *generic_ref,
276 /* If @real_root not set, use @root as fallback */
277 if (!generic_ref->real_root)
278 generic_ref->real_root = root;
279 generic_ref->tree_ref.level = level;
280 generic_ref->tree_ref.root = root;
281 generic_ref->type = BTRFS_REF_METADATA;
284 static inline void btrfs_init_data_ref(struct btrfs_ref *generic_ref,
285 u64 ref_root, u64 ino, u64 offset)
287 /* If @real_root not set, use @root as fallback */
288 if (!generic_ref->real_root)
289 generic_ref->real_root = ref_root;
290 generic_ref->data_ref.ref_root = ref_root;
291 generic_ref->data_ref.ino = ino;
292 generic_ref->data_ref.offset = offset;
293 generic_ref->type = BTRFS_REF_DATA;
296 static inline struct btrfs_delayed_extent_op *
297 btrfs_alloc_delayed_extent_op(void)
299 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
303 btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
306 kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
309 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
311 WARN_ON(refcount_read(&ref->refs) == 0);
312 if (refcount_dec_and_test(&ref->refs)) {
313 WARN_ON(ref->in_tree);
315 case BTRFS_TREE_BLOCK_REF_KEY:
316 case BTRFS_SHARED_BLOCK_REF_KEY:
317 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
319 case BTRFS_EXTENT_DATA_REF_KEY:
320 case BTRFS_SHARED_DATA_REF_KEY:
321 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
329 static inline u64 btrfs_ref_head_to_space_flags(
330 struct btrfs_delayed_ref_head *head_ref)
332 if (head_ref->is_data)
333 return BTRFS_BLOCK_GROUP_DATA;
334 else if (head_ref->is_system)
335 return BTRFS_BLOCK_GROUP_SYSTEM;
336 return BTRFS_BLOCK_GROUP_METADATA;
339 static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *head)
341 if (refcount_dec_and_test(&head->refs))
342 kmem_cache_free(btrfs_delayed_ref_head_cachep, head);
345 int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
346 struct btrfs_ref *generic_ref,
347 struct btrfs_delayed_extent_op *extent_op);
348 int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
349 struct btrfs_ref *generic_ref,
351 int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
352 u64 bytenr, u64 num_bytes,
353 struct btrfs_delayed_extent_op *extent_op);
354 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
355 struct btrfs_delayed_ref_root *delayed_refs,
356 struct btrfs_delayed_ref_head *head);
358 struct btrfs_delayed_ref_head *
359 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
361 int btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs,
362 struct btrfs_delayed_ref_head *head);
363 static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
365 mutex_unlock(&head->mutex);
367 void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
368 struct btrfs_delayed_ref_head *head);
370 struct btrfs_delayed_ref_head *btrfs_select_ref_head(
371 struct btrfs_delayed_ref_root *delayed_refs);
373 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq);
375 void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr);
376 void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans);
377 int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
378 enum btrfs_reserve_flush_enum flush);
379 void btrfs_migrate_to_delayed_refs_rsv(struct btrfs_fs_info *fs_info,
380 struct btrfs_block_rsv *src,
382 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans);
383 bool btrfs_check_space_for_delayed_refs(struct btrfs_fs_info *fs_info);
386 * helper functions to cast a node into its container
388 static inline struct btrfs_delayed_tree_ref *
389 btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
391 return container_of(node, struct btrfs_delayed_tree_ref, node);
394 static inline struct btrfs_delayed_data_ref *
395 btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
397 return container_of(node, struct btrfs_delayed_data_ref, node);