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