1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 2014 Facebook. All rights reserved.
4 */
5
6 #ifndef BTRFS_QGROUP_H
7 #define BTRFS_QGROUP_H
8
9 #include <linux/spinlock.h>
10 #include <linux/rbtree.h>
11 #include <linux/kobject.h>
12 #include "ulist.h"
13 #include "delayed-ref.h"
14 #include "misc.h"
15
16 /*
17 * Btrfs qgroup overview
18 *
19 * Btrfs qgroup splits into 3 main part:
20 * 1) Reserve
21 * Reserve metadata/data space for incoming operations
22 * Affect how qgroup limit works
23 *
24 * 2) Trace
25 * Tell btrfs qgroup to trace dirty extents.
26 *
27 * Dirty extents including:
28 * - Newly allocated extents
29 * - Extents going to be deleted (in this trans)
30 * - Extents whose owner is going to be modified
31 *
32 * This is the main part affects whether qgroup numbers will stay
33 * consistent.
34 * Btrfs qgroup can trace clean extents and won't cause any problem,
35 * but it will consume extra CPU time, it should be avoided if possible.
36 *
37 * 3) Account
38 * Btrfs qgroup will updates its numbers, based on dirty extents traced
39 * in previous step.
40 *
41 * Normally at qgroup rescan and transaction commit time.
42 */
43
44 /*
45 * Special performance optimization for balance.
46 *
47 * For balance, we need to swap subtree of subvolume and reloc trees.
48 * In theory, we need to trace all subtree blocks of both subvolume and reloc
49 * trees, since their owner has changed during such swap.
50 *
51 * However since balance has ensured that both subtrees are containing the
52 * same contents and have the same tree structures, such swap won't cause
53 * qgroup number change.
54 *
55 * But there is a race window between subtree swap and transaction commit,
56 * during that window, if we increase/decrease tree level or merge/split tree
57 * blocks, we still need to trace the original subtrees.
58 *
59 * So for balance, we use a delayed subtree tracing, whose workflow is:
60 *
61 * 1) Record the subtree root block get swapped.
62 *
63 * During subtree swap:
64 * O = Old tree blocks
65 * N = New tree blocks
66 * reloc tree subvolume tree X
67 * Root Root
68 * / \ / \
69 * NA OB OA OB
70 * / | | \ / | | \
71 * NC ND OE OF OC OD OE OF
72 *
73 * In this case, NA and OA are going to be swapped, record (NA, OA) into
74 * subvolume tree X.
75 *
76 * 2) After subtree swap.
77 * reloc tree subvolume tree X
78 * Root Root
79 * / \ / \
80 * OA OB NA OB
81 * / | | \ / | | \
82 * OC OD OE OF NC ND OE OF
83 *
84 * 3a) COW happens for OB
85 * If we are going to COW tree block OB, we check OB's bytenr against
86 * tree X's swapped_blocks structure.
87 * If it doesn't fit any, nothing will happen.
88 *
89 * 3b) COW happens for NA
90 * Check NA's bytenr against tree X's swapped_blocks, and get a hit.
91 * Then we do subtree scan on both subtrees OA and NA.
92 * Resulting 6 tree blocks to be scanned (OA, OC, OD, NA, NC, ND).
93 *
94 * Then no matter what we do to subvolume tree X, qgroup numbers will
95 * still be correct.
96 * Then NA's record gets removed from X's swapped_blocks.
97 *
98 * 4) Transaction commit
99 * Any record in X's swapped_blocks gets removed, since there is no
100 * modification to the swapped subtrees, no need to trigger heavy qgroup
101 * subtree rescan for them.
102 */
103
104 #define BTRFS_QGROUP_RUNTIME_FLAG_CANCEL_RESCAN (1UL << 3)
105 #define BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING (1UL << 4)
106
107 /*
108 * Record a dirty extent, and info qgroup to update quota on it
109 * TODO: Use kmem cache to alloc it.
110 */
111 struct btrfs_qgroup_extent_record {
112 struct rb_node node;
113 u64 bytenr;
114 u64 num_bytes;
115
116 /*
117 * For qgroup reserved data space freeing.
118 *
119 * @data_rsv_refroot and @data_rsv will be recorded after
120 * BTRFS_ADD_DELAYED_EXTENT is called.
121 * And will be used to free reserved qgroup space at
122 * transaction commit time.
123 */
124 u32 data_rsv; /* reserved data space needs to be freed */
125 u64 data_rsv_refroot; /* which root the reserved data belongs to */
126 struct ulist *old_roots;
127 };
128
129 struct btrfs_qgroup_swapped_block {
130 struct rb_node node;
131
132 int level;
133 bool trace_leaf;
134
135 /* bytenr/generation of the tree block in subvolume tree after swap */
136 u64 subvol_bytenr;
137 u64 subvol_generation;
138
139 /* bytenr/generation of the tree block in reloc tree after swap */
140 u64 reloc_bytenr;
141 u64 reloc_generation;
142
143 u64 last_snapshot;
144 struct btrfs_key first_key;
145 };
146
147 /*
148 * Qgroup reservation types:
149 *
150 * DATA:
151 * space reserved for data
152 *
153 * META_PERTRANS:
154 * Space reserved for metadata (per-transaction)
155 * Due to the fact that qgroup data is only updated at transaction commit
156 * time, reserved space for metadata must be kept until transaction
157 * commits.
158 * Any metadata reserved that are used in btrfs_start_transaction() should
159 * be of this type.
160 *
161 * META_PREALLOC:
162 * There are cases where metadata space is reserved before starting
163 * transaction, and then btrfs_join_transaction() to get a trans handle.
164 * Any metadata reserved for such usage should be of this type.
165 * And after join_transaction() part (or all) of such reservation should
166 * be converted into META_PERTRANS.
167 */
168 enum btrfs_qgroup_rsv_type {
169 BTRFS_QGROUP_RSV_DATA,
170 BTRFS_QGROUP_RSV_META_PERTRANS,
171 BTRFS_QGROUP_RSV_META_PREALLOC,
172 BTRFS_QGROUP_RSV_LAST,
173 };
174
175 /*
176 * Represents how many bytes we have reserved for this qgroup.
177 *
178 * Each type should have different reservation behavior.
179 * E.g, data follows its io_tree flag modification, while
180 * *currently* meta is just reserve-and-clear during transaction.
181 *
182 * TODO: Add new type for reservation which can survive transaction commit.
183 * Current metadata reservation behavior is not suitable for such case.
184 */
185 struct btrfs_qgroup_rsv {
186 u64 values[BTRFS_QGROUP_RSV_LAST];
187 };
188
189 /*
190 * one struct for each qgroup, organized in fs_info->qgroup_tree.
191 */
192 struct btrfs_qgroup {
193 u64 qgroupid;
194
195 /*
196 * state
197 */
198 u64 rfer; /* referenced */
199 u64 rfer_cmpr; /* referenced compressed */
200 u64 excl; /* exclusive */
201 u64 excl_cmpr; /* exclusive compressed */
202
203 /*
204 * limits
205 */
206 u64 lim_flags; /* which limits are set */
207 u64 max_rfer;
208 u64 max_excl;
209 u64 rsv_rfer;
210 u64 rsv_excl;
211
212 /*
213 * reservation tracking
214 */
215 struct btrfs_qgroup_rsv rsv;
216
217 /*
218 * lists
219 */
220 struct list_head groups; /* groups this group is member of */
221 struct list_head members; /* groups that are members of this group */
222 struct list_head dirty; /* dirty groups */
223 struct rb_node node; /* tree of qgroups */
224
225 /*
226 * temp variables for accounting operations
227 * Refer to qgroup_shared_accounting() for details.
228 */
229 u64 old_refcnt;
230 u64 new_refcnt;
231
232 /*
233 * Sysfs kobjectid
234 */
235 struct kobject kobj;
236 };
237
btrfs_qgroup_subvolid(u64 qgroupid)238 static inline u64 btrfs_qgroup_subvolid(u64 qgroupid)
239 {
240 return (qgroupid & ((1ULL << BTRFS_QGROUP_LEVEL_SHIFT) - 1));
241 }
242
243 /*
244 * For qgroup event trace points only
245 */
246 enum {
247 ENUM_BIT(QGROUP_RESERVE),
248 ENUM_BIT(QGROUP_RELEASE),
249 ENUM_BIT(QGROUP_FREE),
250 };
251
252 int btrfs_quota_enable(struct btrfs_fs_info *fs_info);
253 int btrfs_quota_disable(struct btrfs_fs_info *fs_info);
254 int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
255 void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);
256 int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
257 bool interruptible);
258 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
259 u64 dst);
260 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
261 u64 dst);
262 int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid);
263 int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid);
264 int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
265 struct btrfs_qgroup_limit *limit);
266 int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info);
267 void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
268 struct btrfs_delayed_extent_op;
269
270 /*
271 * Inform qgroup to trace one dirty extent, its info is recorded in @record.
272 * So qgroup can account it at transaction committing time.
273 *
274 * No lock version, caller must acquire delayed ref lock and allocated memory,
275 * then call btrfs_qgroup_trace_extent_post() after exiting lock context.
276 *
277 * Return 0 for success insert
278 * Return >0 for existing record, caller can free @record safely.
279 * Error is not possible
280 */
281 int btrfs_qgroup_trace_extent_nolock(
282 struct btrfs_fs_info *fs_info,
283 struct btrfs_delayed_ref_root *delayed_refs,
284 struct btrfs_qgroup_extent_record *record);
285
286 /*
287 * Post handler after qgroup_trace_extent_nolock().
288 *
289 * NOTE: Current qgroup does the expensive backref walk at transaction
290 * committing time with TRANS_STATE_COMMIT_DOING, this blocks incoming
291 * new transaction.
292 * This is designed to allow btrfs_find_all_roots() to get correct new_roots
293 * result.
294 *
295 * However for old_roots there is no need to do backref walk at that time,
296 * since we search commit roots to walk backref and result will always be
297 * correct.
298 *
299 * Due to the nature of no lock version, we can't do backref there.
300 * So we must call btrfs_qgroup_trace_extent_post() after exiting
301 * spinlock context.
302 *
303 * TODO: If we can fix and prove btrfs_find_all_roots() can get correct result
304 * using current root, then we can move all expensive backref walk out of
305 * transaction committing, but not now as qgroup accounting will be wrong again.
306 */
307 int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
308 struct btrfs_qgroup_extent_record *qrecord);
309
310 /*
311 * Inform qgroup to trace one dirty extent, specified by @bytenr and
312 * @num_bytes.
313 * So qgroup can account it at commit trans time.
314 *
315 * Better encapsulated version, with memory allocation and backref walk for
316 * commit roots.
317 * So this can sleep.
318 *
319 * Return 0 if the operation is done.
320 * Return <0 for error, like memory allocation failure or invalid parameter
321 * (NULL trans)
322 */
323 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
324 u64 num_bytes);
325
326 /*
327 * Inform qgroup to trace all leaf items of data
328 *
329 * Return 0 for success
330 * Return <0 for error(ENOMEM)
331 */
332 int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
333 struct extent_buffer *eb);
334 /*
335 * Inform qgroup to trace a whole subtree, including all its child tree
336 * blocks and data.
337 * The root tree block is specified by @root_eb.
338 *
339 * Normally used by relocation(tree block swap) and subvolume deletion.
340 *
341 * Return 0 for success
342 * Return <0 for error(ENOMEM or tree search error)
343 */
344 int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
345 struct extent_buffer *root_eb,
346 u64 root_gen, int root_level);
347 int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
348 u64 num_bytes, struct ulist *old_roots,
349 struct ulist *new_roots);
350 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans);
351 int btrfs_run_qgroups(struct btrfs_trans_handle *trans);
352 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
353 u64 objectid, struct btrfs_qgroup_inherit *inherit);
354 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
355 u64 ref_root, u64 num_bytes,
356 enum btrfs_qgroup_rsv_type type);
357
358 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
359 int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
360 u64 rfer, u64 excl);
361 #endif
362
363 /* New io_tree based accurate qgroup reserve API */
364 int btrfs_qgroup_reserve_data(struct btrfs_inode *inode,
365 struct extent_changeset **reserved, u64 start, u64 len);
366 int btrfs_qgroup_release_data(struct btrfs_inode *inode, u64 start, u64 len);
367 int btrfs_qgroup_free_data(struct btrfs_inode *inode,
368 struct extent_changeset *reserved, u64 start,
369 u64 len);
370 int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
371 enum btrfs_qgroup_rsv_type type, bool enforce);
372 int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
373 enum btrfs_qgroup_rsv_type type, bool enforce,
374 bool noflush);
375 /* Reserve metadata space for pertrans and prealloc type */
btrfs_qgroup_reserve_meta_pertrans(struct btrfs_root * root,int num_bytes,bool enforce)376 static inline int btrfs_qgroup_reserve_meta_pertrans(struct btrfs_root *root,
377 int num_bytes, bool enforce)
378 {
379 return __btrfs_qgroup_reserve_meta(root, num_bytes,
380 BTRFS_QGROUP_RSV_META_PERTRANS,
381 enforce, false);
382 }
btrfs_qgroup_reserve_meta_prealloc(struct btrfs_root * root,int num_bytes,bool enforce,bool noflush)383 static inline int btrfs_qgroup_reserve_meta_prealloc(struct btrfs_root *root,
384 int num_bytes, bool enforce,
385 bool noflush)
386 {
387 return __btrfs_qgroup_reserve_meta(root, num_bytes,
388 BTRFS_QGROUP_RSV_META_PREALLOC,
389 enforce, noflush);
390 }
391
392 void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
393 enum btrfs_qgroup_rsv_type type);
394
395 /* Free per-transaction meta reservation for error handling */
btrfs_qgroup_free_meta_pertrans(struct btrfs_root * root,int num_bytes)396 static inline void btrfs_qgroup_free_meta_pertrans(struct btrfs_root *root,
397 int num_bytes)
398 {
399 __btrfs_qgroup_free_meta(root, num_bytes,
400 BTRFS_QGROUP_RSV_META_PERTRANS);
401 }
402
403 /* Pre-allocated meta reservation can be freed at need */
btrfs_qgroup_free_meta_prealloc(struct btrfs_root * root,int num_bytes)404 static inline void btrfs_qgroup_free_meta_prealloc(struct btrfs_root *root,
405 int num_bytes)
406 {
407 __btrfs_qgroup_free_meta(root, num_bytes,
408 BTRFS_QGROUP_RSV_META_PREALLOC);
409 }
410
411 /*
412 * Per-transaction meta reservation should be all freed at transaction commit
413 * time
414 */
415 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root);
416
417 /*
418 * Convert @num_bytes of META_PREALLOCATED reservation to META_PERTRANS.
419 *
420 * This is called when preallocated meta reservation needs to be used.
421 * Normally after btrfs_join_transaction() call.
422 */
423 void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes);
424
425 void btrfs_qgroup_check_reserved_leak(struct btrfs_inode *inode);
426
427 /* btrfs_qgroup_swapped_blocks related functions */
428 void btrfs_qgroup_init_swapped_blocks(
429 struct btrfs_qgroup_swapped_blocks *swapped_blocks);
430
431 void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root);
432 int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
433 struct btrfs_root *subvol_root,
434 struct btrfs_block_group *bg,
435 struct extent_buffer *subvol_parent, int subvol_slot,
436 struct extent_buffer *reloc_parent, int reloc_slot,
437 u64 last_snapshot);
438 int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
439 struct btrfs_root *root, struct extent_buffer *eb);
440 void btrfs_qgroup_destroy_extent_records(struct btrfs_transaction *trans);
441 bool btrfs_check_quota_leak(struct btrfs_fs_info *fs_info);
442
443 #endif
444
