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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2008 Oracle. All rights reserved.
4 */
5
6#ifndef BTRFS_DELAYED_REF_H
7#define BTRFS_DELAYED_REF_H
8
9#include <linux/refcount.h>
10
11/* these are the possible values of struct btrfs_delayed_ref_node->action */
12enum btrfs_delayed_ref_action {
13 /* Add one backref to the tree */
14 BTRFS_ADD_DELAYED_REF = 1,
15 /* Delete one backref from the tree */
16 BTRFS_DROP_DELAYED_REF,
17 /* Record a full extent allocation */
18 BTRFS_ADD_DELAYED_EXTENT,
19 /* Not changing ref count on head ref */
20 BTRFS_UPDATE_DELAYED_HEAD,
21} __packed;
22
23struct btrfs_delayed_ref_node {
24 struct rb_node ref_node;
25 /*
26 * If action is BTRFS_ADD_DELAYED_REF, also link this node to
27 * ref_head->ref_add_list, then we do not need to iterate the
28 * whole ref_head->ref_list to find BTRFS_ADD_DELAYED_REF nodes.
29 */
30 struct list_head add_list;
31
32 /* the starting bytenr of the extent */
33 u64 bytenr;
34
35 /* the size of the extent */
36 u64 num_bytes;
37
38 /* seq number to keep track of insertion order */
39 u64 seq;
40
41 /* ref count on this data structure */
42 refcount_t refs;
43
44 /*
45 * how many refs is this entry adding or deleting. For
46 * head refs, this may be a negative number because it is keeping
47 * track of the total mods done to the reference count.
48 * For individual refs, this will always be a positive number
49 *
50 * It may be more than one, since it is possible for a single
51 * parent to have more than one ref on an extent
52 */
53 int ref_mod;
54
55 unsigned int action:8;
56 unsigned int type:8;
57};
58
59struct btrfs_delayed_extent_op {
60 struct btrfs_disk_key key;
61 u8 level;
62 bool update_key;
63 bool update_flags;
64 u64 flags_to_set;
65};
66
67/*
68 * the head refs are used to hold a lock on a given extent, which allows us
69 * to make sure that only one process is running the delayed refs
70 * at a time for a single extent. They also store the sum of all the
71 * reference count modifications we've queued up.
72 */
73struct btrfs_delayed_ref_head {
74 u64 bytenr;
75 u64 num_bytes;
76 /*
77 * For insertion into struct btrfs_delayed_ref_root::href_root.
78 * Keep it in the same cache line as 'bytenr' for more efficient
79 * searches in the rbtree.
80 */
81 struct rb_node href_node;
82 /*
83 * the mutex is held while running the refs, and it is also
84 * held when checking the sum of reference modifications.
85 */
86 struct mutex mutex;
87
88 refcount_t refs;
89
90 /* Protects 'ref_tree' and 'ref_add_list'. */
91 spinlock_t lock;
92 struct rb_root_cached ref_tree;
93 /* accumulate add BTRFS_ADD_DELAYED_REF nodes to this ref_add_list. */
94 struct list_head ref_add_list;
95
96 struct btrfs_delayed_extent_op *extent_op;
97
98 /*
99 * This is used to track the final ref_mod from all the refs associated
100 * with this head ref, this is not adjusted as delayed refs are run,
101 * this is meant to track if we need to do the csum accounting or not.
102 */
103 int total_ref_mod;
104
105 /*
106 * This is the current outstanding mod references for this bytenr. This
107 * is used with lookup_extent_info to get an accurate reference count
108 * for a bytenr, so it is adjusted as delayed refs are run so that any
109 * on disk reference count + ref_mod is accurate.
110 */
111 int ref_mod;
112
113 /*
114 * The root that triggered the allocation when must_insert_reserved is
115 * set to true.
116 */
117 u64 owning_root;
118
119 /*
120 * Track reserved bytes when setting must_insert_reserved. On success
121 * or cleanup, we will need to free the reservation.
122 */
123 u64 reserved_bytes;
124
125 /*
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.
131 *
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.
136 */
137 bool must_insert_reserved;
138
139 bool is_data;
140 bool is_system;
141 bool processing;
142};
143
144struct btrfs_delayed_tree_ref {
145 struct btrfs_delayed_ref_node node;
146 u64 root;
147 u64 parent;
148 int level;
149};
150
151struct btrfs_delayed_data_ref {
152 struct btrfs_delayed_ref_node node;
153 u64 root;
154 u64 parent;
155 u64 objectid;
156 u64 offset;
157};
158
159enum btrfs_delayed_ref_flags {
160 /* Indicate that we are flushing delayed refs for the commit */
161 BTRFS_DELAYED_REFS_FLUSHING,
162};
163
164struct btrfs_delayed_ref_root {
165 /* head ref rbtree */
166 struct rb_root_cached href_root;
167
168 /* dirty extent records */
169 struct rb_root dirty_extent_root;
170
171 /* this spin lock protects the rbtree and the entries inside */
172 spinlock_t lock;
173
174 /* how many delayed ref updates we've queued, used by the
175 * throttling code
176 */
177 atomic_t num_entries;
178
179 /* total number of head nodes in tree */
180 unsigned long num_heads;
181
182 /* total number of head nodes ready for processing */
183 unsigned long num_heads_ready;
184
185 u64 pending_csums;
186
187 unsigned long flags;
188
189 u64 run_delayed_start;
190
191 /*
192 * To make qgroup to skip given root.
193 * This is for snapshot, as btrfs_qgroup_inherit() will manually
194 * modify counters for snapshot and its source, so we should skip
195 * the snapshot in new_root/old_roots or it will get calculated twice
196 */
197 u64 qgroup_to_skip;
198};
199
200enum btrfs_ref_type {
201 BTRFS_REF_NOT_SET,
202 BTRFS_REF_DATA,
203 BTRFS_REF_METADATA,
204 BTRFS_REF_LAST,
205} __packed;
206
207struct btrfs_data_ref {
208 /* For EXTENT_DATA_REF */
209
210 /* Root which owns this data reference. */
211 u64 ref_root;
212
213 /* Inode which refers to this data extent */
214 u64 ino;
215
216 /*
217 * file_offset - extent_offset
218 *
219 * file_offset is the key.offset of the EXTENT_DATA key.
220 * extent_offset is btrfs_file_extent_offset() of the EXTENT_DATA data.
221 */
222 u64 offset;
223};
224
225struct btrfs_tree_ref {
226 /*
227 * Level of this tree block
228 *
229 * Shared for skinny (TREE_BLOCK_REF) and normal tree ref.
230 */
231 int level;
232
233 /*
234 * Root which owns this tree block reference.
235 *
236 * For TREE_BLOCK_REF (skinny metadata, either inline or keyed)
237 */
238 u64 ref_root;
239
240 /* For non-skinny metadata, no special member needed */
241};
242
243struct btrfs_ref {
244 enum btrfs_ref_type type;
245 enum btrfs_delayed_ref_action action;
246
247 /*
248 * Whether this extent should go through qgroup record.
249 *
250 * Normally false, but for certain cases like delayed subtree scan,
251 * setting this flag can hugely reduce qgroup overhead.
252 */
253 bool skip_qgroup;
254
255#ifdef CONFIG_BTRFS_FS_REF_VERIFY
256 /* Through which root is this modification. */
257 u64 real_root;
258#endif
259 u64 bytenr;
260 u64 len;
261 u64 owning_root;
262
263 /* Bytenr of the parent tree block */
264 u64 parent;
265 union {
266 struct btrfs_data_ref data_ref;
267 struct btrfs_tree_ref tree_ref;
268 };
269};
270
271extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
272extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
273extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
274extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
275
276int __init btrfs_delayed_ref_init(void);
277void __cold btrfs_delayed_ref_exit(void);
278
279static inline u64 btrfs_calc_delayed_ref_bytes(const struct btrfs_fs_info *fs_info,
280 int num_delayed_refs)
281{
282 u64 num_bytes;
283
284 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_delayed_refs);
285
286 /*
287 * We have to check the mount option here because we could be enabling
288 * the free space tree for the first time and don't have the compat_ro
289 * option set yet.
290 *
291 * We need extra reservations if we have the free space tree because
292 * we'll have to modify that tree as well.
293 */
294 if (btrfs_test_opt(fs_info, FREE_SPACE_TREE))
295 num_bytes *= 2;
296
297 return num_bytes;
298}
299
300static inline u64 btrfs_calc_delayed_ref_csum_bytes(const struct btrfs_fs_info *fs_info,
301 int num_csum_items)
302{
303 /*
304 * Deleting csum items does not result in new nodes/leaves and does not
305 * require changing the free space tree, only the csum tree, so this is
306 * all we need.
307 */
308 return btrfs_calc_metadata_size(fs_info, num_csum_items);
309}
310
311static inline void btrfs_init_generic_ref(struct btrfs_ref *generic_ref,
312 int action, u64 bytenr, u64 len,
313 u64 parent, u64 owning_root)
314{
315 generic_ref->action = action;
316 generic_ref->bytenr = bytenr;
317 generic_ref->len = len;
318 generic_ref->parent = parent;
319 generic_ref->owning_root = owning_root;
320}
321
322static inline void btrfs_init_tree_ref(struct btrfs_ref *generic_ref, int level,
323 u64 root, u64 mod_root, bool skip_qgroup)
324{
325#ifdef CONFIG_BTRFS_FS_REF_VERIFY
326 /* If @real_root not set, use @root as fallback */
327 generic_ref->real_root = mod_root ?: root;
328#endif
329 generic_ref->tree_ref.level = level;
330 generic_ref->tree_ref.ref_root = root;
331 generic_ref->type = BTRFS_REF_METADATA;
332 if (skip_qgroup || !(is_fstree(root) &&
333 (!mod_root || is_fstree(mod_root))))
334 generic_ref->skip_qgroup = true;
335 else
336 generic_ref->skip_qgroup = false;
337
338}
339
340static inline void btrfs_init_data_ref(struct btrfs_ref *generic_ref,
341 u64 ref_root, u64 ino, u64 offset, u64 mod_root,
342 bool skip_qgroup)
343{
344#ifdef CONFIG_BTRFS_FS_REF_VERIFY
345 /* If @real_root not set, use @root as fallback */
346 generic_ref->real_root = mod_root ?: ref_root;
347#endif
348 generic_ref->data_ref.ref_root = ref_root;
349 generic_ref->data_ref.ino = ino;
350 generic_ref->data_ref.offset = offset;
351 generic_ref->type = BTRFS_REF_DATA;
352 if (skip_qgroup || !(is_fstree(ref_root) &&
353 (!mod_root || is_fstree(mod_root))))
354 generic_ref->skip_qgroup = true;
355 else
356 generic_ref->skip_qgroup = false;
357}
358
359static inline struct btrfs_delayed_extent_op *
360btrfs_alloc_delayed_extent_op(void)
361{
362 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
363}
364
365static inline void
366btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
367{
368 if (op)
369 kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
370}
371
372static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
373{
374 if (refcount_dec_and_test(&ref->refs)) {
375 WARN_ON(!RB_EMPTY_NODE(&ref->ref_node));
376 switch (ref->type) {
377 case BTRFS_TREE_BLOCK_REF_KEY:
378 case BTRFS_SHARED_BLOCK_REF_KEY:
379 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
380 break;
381 case BTRFS_EXTENT_DATA_REF_KEY:
382 case BTRFS_SHARED_DATA_REF_KEY:
383 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
384 break;
385 default:
386 BUG();
387 }
388 }
389}
390
391static inline u64 btrfs_ref_head_to_space_flags(
392 struct btrfs_delayed_ref_head *head_ref)
393{
394 if (head_ref->is_data)
395 return BTRFS_BLOCK_GROUP_DATA;
396 else if (head_ref->is_system)
397 return BTRFS_BLOCK_GROUP_SYSTEM;
398 return BTRFS_BLOCK_GROUP_METADATA;
399}
400
401static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *head)
402{
403 if (refcount_dec_and_test(&head->refs))
404 kmem_cache_free(btrfs_delayed_ref_head_cachep, head);
405}
406
407int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
408 struct btrfs_ref *generic_ref,
409 struct btrfs_delayed_extent_op *extent_op);
410int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
411 struct btrfs_ref *generic_ref,
412 u64 reserved);
413int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
414 u64 bytenr, u64 num_bytes,
415 struct btrfs_delayed_extent_op *extent_op);
416void btrfs_merge_delayed_refs(struct btrfs_fs_info *fs_info,
417 struct btrfs_delayed_ref_root *delayed_refs,
418 struct btrfs_delayed_ref_head *head);
419
420struct btrfs_delayed_ref_head *
421btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
422 u64 bytenr);
423int btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs,
424 struct btrfs_delayed_ref_head *head);
425static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
426{
427 mutex_unlock(&head->mutex);
428}
429void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
430 struct btrfs_delayed_ref_head *head);
431
432struct btrfs_delayed_ref_head *btrfs_select_ref_head(
433 struct btrfs_delayed_ref_root *delayed_refs);
434
435int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq);
436
437void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr_refs, int nr_csums);
438void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans);
439void btrfs_inc_delayed_refs_rsv_bg_inserts(struct btrfs_fs_info *fs_info);
440void btrfs_dec_delayed_refs_rsv_bg_inserts(struct btrfs_fs_info *fs_info);
441void btrfs_inc_delayed_refs_rsv_bg_updates(struct btrfs_fs_info *fs_info);
442void btrfs_dec_delayed_refs_rsv_bg_updates(struct btrfs_fs_info *fs_info);
443int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
444 enum btrfs_reserve_flush_enum flush);
445void btrfs_migrate_to_delayed_refs_rsv(struct btrfs_fs_info *fs_info,
446 u64 num_bytes);
447bool btrfs_check_space_for_delayed_refs(struct btrfs_fs_info *fs_info);
448
449/*
450 * helper functions to cast a node into its container
451 */
452static inline struct btrfs_delayed_tree_ref *
453btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
454{
455 return container_of(node, struct btrfs_delayed_tree_ref, node);
456}
457
458static inline struct btrfs_delayed_data_ref *
459btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
460{
461 return container_of(node, struct btrfs_delayed_data_ref, node);
462}
463
464#endif
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 /* is this node still in the rbtree? */
56 unsigned int is_head:1;
57 unsigned int in_tree:1;
58};
59
60struct btrfs_delayed_extent_op {
61 struct btrfs_disk_key key;
62 u64 flags_to_set;
63 int level;
64 unsigned int update_key:1;
65 unsigned int update_flags:1;
66 unsigned int is_data:1;
67};
68
69/*
70 * the head refs are used to hold a lock on a given extent, which allows us
71 * to make sure that only one process is running the delayed refs
72 * at a time for a single extent. They also store the sum of all the
73 * reference count modifications we've queued up.
74 */
75struct btrfs_delayed_ref_head {
76 struct btrfs_delayed_ref_node node;
77
78 /*
79 * the mutex is held while running the refs, and it is also
80 * held when checking the sum of reference modifications.
81 */
82 struct mutex mutex;
83
84 spinlock_t lock;
85 struct rb_root ref_root;
86
87 struct rb_node href_node;
88
89 struct btrfs_delayed_extent_op *extent_op;
90 /*
91 * when a new extent is allocated, it is just reserved in memory
92 * The actual extent isn't inserted into the extent allocation tree
93 * until the delayed ref is processed. must_insert_reserved is
94 * used to flag a delayed ref so the accounting can be updated
95 * when a full insert is done.
96 *
97 * It is possible the extent will be freed before it is ever
98 * inserted into the extent allocation tree. In this case
99 * we need to update the in ram accounting to properly reflect
100 * the free has happened.
101 */
102 unsigned int must_insert_reserved:1;
103 unsigned int is_data:1;
104 unsigned int processing:1;
105};
106
107struct btrfs_delayed_tree_ref {
108 struct btrfs_delayed_ref_node node;
109 u64 root;
110 u64 parent;
111 int level;
112};
113
114struct btrfs_delayed_data_ref {
115 struct btrfs_delayed_ref_node node;
116 u64 root;
117 u64 parent;
118 u64 objectid;
119 u64 offset;
120};
121
122struct btrfs_delayed_ref_root {
123 /* head ref rbtree */
124 struct rb_root href_root;
125
126 /* this spin lock protects the rbtree and the entries inside */
127 spinlock_t lock;
128
129 /* how many delayed ref updates we've queued, used by the
130 * throttling code
131 */
132 atomic_t num_entries;
133
134 /* total number of head nodes in tree */
135 unsigned long num_heads;
136
137 /* total number of head nodes ready for processing */
138 unsigned long num_heads_ready;
139
140 /*
141 * set when the tree is flushing before a transaction commit,
142 * used by the throttling code to decide if new updates need
143 * to be run right away
144 */
145 int flushing;
146
147 u64 run_delayed_start;
148};
149
150extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
151extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
152extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
153extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
154
155int btrfs_delayed_ref_init(void);
156void btrfs_delayed_ref_exit(void);
157
158static inline struct btrfs_delayed_extent_op *
159btrfs_alloc_delayed_extent_op(void)
160{
161 return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
162}
163
164static inline void
165btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
166{
167 if (op)
168 kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
169}
170
171static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
172{
173 WARN_ON(atomic_read(&ref->refs) == 0);
174 if (atomic_dec_and_test(&ref->refs)) {
175 WARN_ON(ref->in_tree);
176 switch (ref->type) {
177 case BTRFS_TREE_BLOCK_REF_KEY:
178 case BTRFS_SHARED_BLOCK_REF_KEY:
179 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
180 break;
181 case BTRFS_EXTENT_DATA_REF_KEY:
182 case BTRFS_SHARED_DATA_REF_KEY:
183 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
184 break;
185 case 0:
186 kmem_cache_free(btrfs_delayed_ref_head_cachep, ref);
187 break;
188 default:
189 BUG();
190 }
191 }
192}
193
194int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
195 struct btrfs_trans_handle *trans,
196 u64 bytenr, u64 num_bytes, u64 parent,
197 u64 ref_root, int level, int action,
198 struct btrfs_delayed_extent_op *extent_op,
199 int for_cow);
200int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
201 struct btrfs_trans_handle *trans,
202 u64 bytenr, u64 num_bytes,
203 u64 parent, u64 ref_root,
204 u64 owner, u64 offset, int action,
205 struct btrfs_delayed_extent_op *extent_op,
206 int for_cow);
207int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
208 struct btrfs_trans_handle *trans,
209 u64 bytenr, u64 num_bytes,
210 struct btrfs_delayed_extent_op *extent_op);
211void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
212 struct btrfs_fs_info *fs_info,
213 struct btrfs_delayed_ref_root *delayed_refs,
214 struct btrfs_delayed_ref_head *head);
215
216struct btrfs_delayed_ref_head *
217btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
218int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
219 struct btrfs_delayed_ref_head *head);
220static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
221{
222 mutex_unlock(&head->mutex);
223}
224
225
226struct btrfs_delayed_ref_head *
227btrfs_select_ref_head(struct btrfs_trans_handle *trans);
228
229int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
230 struct btrfs_delayed_ref_root *delayed_refs,
231 u64 seq);
232
233/*
234 * delayed refs with a ref_seq > 0 must be held back during backref walking.
235 * this only applies to items in one of the fs-trees. for_cow items never need
236 * to be held back, so they won't get a ref_seq number.
237 */
238static inline int need_ref_seq(int for_cow, u64 rootid)
239{
240 if (for_cow)
241 return 0;
242
243 if (rootid == BTRFS_FS_TREE_OBJECTID)
244 return 1;
245
246 if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
247 return 1;
248
249 return 0;
250}
251
252/*
253 * a node might live in a head or a regular ref, this lets you
254 * test for the proper type to use.
255 */
256static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
257{
258 return node->is_head;
259}
260
261/*
262 * helper functions to cast a node into its container
263 */
264static inline struct btrfs_delayed_tree_ref *
265btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
266{
267 WARN_ON(btrfs_delayed_ref_is_head(node));
268 return container_of(node, struct btrfs_delayed_tree_ref, node);
269}
270
271static inline struct btrfs_delayed_data_ref *
272btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
273{
274 WARN_ON(btrfs_delayed_ref_is_head(node));
275 return container_of(node, struct btrfs_delayed_data_ref, node);
276}
277
278static inline struct btrfs_delayed_ref_head *
279btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
280{
281 WARN_ON(!btrfs_delayed_ref_is_head(node));
282 return container_of(node, struct btrfs_delayed_ref_head, node);
283}
284#endif