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