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

source code of linux/fs/btrfs/delayed-ref.h