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 
224 	/*
225 	 * For qgroup iteration usage.
226 	 *
227 	 * The iteration list should always be empty until qgroup_iterator_add()
228 	 * is called.  And should be reset to empty after the iteration is
229 	 * finished.
230 	 */
231 	struct list_head iterator;
232 	struct rb_node node;	  /* tree of qgroups */
233 
234 	/*
235 	 * temp variables for accounting operations
236 	 * Refer to qgroup_shared_accounting() for details.
237 	 */
238 	u64 old_refcnt;
239 	u64 new_refcnt;
240 
241 	/*
242 	 * Sysfs kobjectid
243 	 */
244 	struct kobject kobj;
245 };
246 
btrfs_qgroup_subvolid(u64 qgroupid)247 static inline u64 btrfs_qgroup_subvolid(u64 qgroupid)
248 {
249 	return (qgroupid & ((1ULL << BTRFS_QGROUP_LEVEL_SHIFT) - 1));
250 }
251 
252 /*
253  * For qgroup event trace points only
254  */
255 enum {
256 	ENUM_BIT(QGROUP_RESERVE),
257 	ENUM_BIT(QGROUP_RELEASE),
258 	ENUM_BIT(QGROUP_FREE),
259 };
260 
261 int btrfs_quota_enable(struct btrfs_fs_info *fs_info);
262 int btrfs_quota_disable(struct btrfs_fs_info *fs_info);
263 int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
264 void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);
265 int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
266 				     bool interruptible);
267 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
268 			      u64 dst);
269 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
270 			      u64 dst);
271 int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid);
272 int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid);
273 int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
274 		       struct btrfs_qgroup_limit *limit);
275 int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info);
276 void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
277 struct btrfs_delayed_extent_op;
278 
279 /*
280  * Inform qgroup to trace one dirty extent, its info is recorded in @record.
281  * So qgroup can account it at transaction committing time.
282  *
283  * No lock version, caller must acquire delayed ref lock and allocated memory,
284  * then call btrfs_qgroup_trace_extent_post() after exiting lock context.
285  *
286  * Return 0 for success insert
287  * Return >0 for existing record, caller can free @record safely.
288  * Error is not possible
289  */
290 int btrfs_qgroup_trace_extent_nolock(
291 		struct btrfs_fs_info *fs_info,
292 		struct btrfs_delayed_ref_root *delayed_refs,
293 		struct btrfs_qgroup_extent_record *record);
294 
295 /*
296  * Post handler after qgroup_trace_extent_nolock().
297  *
298  * NOTE: Current qgroup does the expensive backref walk at transaction
299  * committing time with TRANS_STATE_COMMIT_DOING, this blocks incoming
300  * new transaction.
301  * This is designed to allow btrfs_find_all_roots() to get correct new_roots
302  * result.
303  *
304  * However for old_roots there is no need to do backref walk at that time,
305  * since we search commit roots to walk backref and result will always be
306  * correct.
307  *
308  * Due to the nature of no lock version, we can't do backref there.
309  * So we must call btrfs_qgroup_trace_extent_post() after exiting
310  * spinlock context.
311  *
312  * TODO: If we can fix and prove btrfs_find_all_roots() can get correct result
313  * using current root, then we can move all expensive backref walk out of
314  * transaction committing, but not now as qgroup accounting will be wrong again.
315  */
316 int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
317 				   struct btrfs_qgroup_extent_record *qrecord);
318 
319 /*
320  * Inform qgroup to trace one dirty extent, specified by @bytenr and
321  * @num_bytes.
322  * So qgroup can account it at commit trans time.
323  *
324  * Better encapsulated version, with memory allocation and backref walk for
325  * commit roots.
326  * So this can sleep.
327  *
328  * Return 0 if the operation is done.
329  * Return <0 for error, like memory allocation failure or invalid parameter
330  * (NULL trans)
331  */
332 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
333 			      u64 num_bytes);
334 
335 /*
336  * Inform qgroup to trace all leaf items of data
337  *
338  * Return 0 for success
339  * Return <0 for error(ENOMEM)
340  */
341 int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
342 				  struct extent_buffer *eb);
343 /*
344  * Inform qgroup to trace a whole subtree, including all its child tree
345  * blocks and data.
346  * The root tree block is specified by @root_eb.
347  *
348  * Normally used by relocation(tree block swap) and subvolume deletion.
349  *
350  * Return 0 for success
351  * Return <0 for error(ENOMEM or tree search error)
352  */
353 int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
354 			       struct extent_buffer *root_eb,
355 			       u64 root_gen, int root_level);
356 int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
357 				u64 num_bytes, struct ulist *old_roots,
358 				struct ulist *new_roots);
359 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans);
360 int btrfs_run_qgroups(struct btrfs_trans_handle *trans);
361 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
362 			 u64 objectid, struct btrfs_qgroup_inherit *inherit);
363 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
364 			       u64 ref_root, u64 num_bytes,
365 			       enum btrfs_qgroup_rsv_type type);
366 
367 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
368 int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
369 			       u64 rfer, u64 excl);
370 #endif
371 
372 /* New io_tree based accurate qgroup reserve API */
373 int btrfs_qgroup_reserve_data(struct btrfs_inode *inode,
374 			struct extent_changeset **reserved, u64 start, u64 len);
375 int btrfs_qgroup_release_data(struct btrfs_inode *inode, u64 start, u64 len, u64 *released);
376 int btrfs_qgroup_free_data(struct btrfs_inode *inode,
377 			   struct extent_changeset *reserved, u64 start,
378 			   u64 len, u64 *freed);
379 int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
380 			      enum btrfs_qgroup_rsv_type type, bool enforce);
381 int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
382 				enum btrfs_qgroup_rsv_type type, bool enforce,
383 				bool noflush);
384 /* Reserve metadata space for pertrans and prealloc type */
btrfs_qgroup_reserve_meta_pertrans(struct btrfs_root * root,int num_bytes,bool enforce)385 static inline int btrfs_qgroup_reserve_meta_pertrans(struct btrfs_root *root,
386 				int num_bytes, bool enforce)
387 {
388 	return __btrfs_qgroup_reserve_meta(root, num_bytes,
389 					   BTRFS_QGROUP_RSV_META_PERTRANS,
390 					   enforce, false);
391 }
btrfs_qgroup_reserve_meta_prealloc(struct btrfs_root * root,int num_bytes,bool enforce,bool noflush)392 static inline int btrfs_qgroup_reserve_meta_prealloc(struct btrfs_root *root,
393 						     int num_bytes, bool enforce,
394 						     bool noflush)
395 {
396 	return __btrfs_qgroup_reserve_meta(root, num_bytes,
397 					   BTRFS_QGROUP_RSV_META_PREALLOC,
398 					   enforce, noflush);
399 }
400 
401 void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
402 			     enum btrfs_qgroup_rsv_type type);
403 
404 /* Free per-transaction meta reservation for error handling */
btrfs_qgroup_free_meta_pertrans(struct btrfs_root * root,int num_bytes)405 static inline void btrfs_qgroup_free_meta_pertrans(struct btrfs_root *root,
406 						   int num_bytes)
407 {
408 	__btrfs_qgroup_free_meta(root, num_bytes,
409 			BTRFS_QGROUP_RSV_META_PERTRANS);
410 }
411 
412 /* Pre-allocated meta reservation can be freed at need */
btrfs_qgroup_free_meta_prealloc(struct btrfs_root * root,int num_bytes)413 static inline void btrfs_qgroup_free_meta_prealloc(struct btrfs_root *root,
414 						   int num_bytes)
415 {
416 	__btrfs_qgroup_free_meta(root, num_bytes,
417 			BTRFS_QGROUP_RSV_META_PREALLOC);
418 }
419 
420 /*
421  * Per-transaction meta reservation should be all freed at transaction commit
422  * time
423  */
424 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root);
425 
426 /*
427  * Convert @num_bytes of META_PREALLOCATED reservation to META_PERTRANS.
428  *
429  * This is called when preallocated meta reservation needs to be used.
430  * Normally after btrfs_join_transaction() call.
431  */
432 void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes);
433 
434 void btrfs_qgroup_check_reserved_leak(struct btrfs_inode *inode);
435 
436 /* btrfs_qgroup_swapped_blocks related functions */
437 void btrfs_qgroup_init_swapped_blocks(
438 	struct btrfs_qgroup_swapped_blocks *swapped_blocks);
439 
440 void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root);
441 int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
442 		struct btrfs_root *subvol_root,
443 		struct btrfs_block_group *bg,
444 		struct extent_buffer *subvol_parent, int subvol_slot,
445 		struct extent_buffer *reloc_parent, int reloc_slot,
446 		u64 last_snapshot);
447 int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
448 		struct btrfs_root *root, struct extent_buffer *eb);
449 void btrfs_qgroup_destroy_extent_records(struct btrfs_transaction *trans);
450 bool btrfs_check_quota_leak(struct btrfs_fs_info *fs_info);
451 
452 #endif
453