summaryrefslogtreecommitdiffstats
path: root/fs/btrfs/qgroup.h
blob: c382923f7628e3262d442d30569fb240df9c456a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2014 Facebook.  All rights reserved.
 */

#ifndef BTRFS_QGROUP_H
#define BTRFS_QGROUP_H

#include <linux/spinlock.h>
#include <linux/rbtree.h>
#include <linux/kobject.h>
#include "ulist.h"
#include "delayed-ref.h"

/*
 * Btrfs qgroup overview
 *
 * Btrfs qgroup splits into 3 main part:
 * 1) Reserve
 *    Reserve metadata/data space for incoming operations
 *    Affect how qgroup limit works
 *
 * 2) Trace
 *    Tell btrfs qgroup to trace dirty extents.
 *
 *    Dirty extents including:
 *    - Newly allocated extents
 *    - Extents going to be deleted (in this trans)
 *    - Extents whose owner is going to be modified
 *
 *    This is the main part affects whether qgroup numbers will stay
 *    consistent.
 *    Btrfs qgroup can trace clean extents and won't cause any problem,
 *    but it will consume extra CPU time, it should be avoided if possible.
 *
 * 3) Account
 *    Btrfs qgroup will updates its numbers, based on dirty extents traced
 *    in previous step.
 *
 *    Normally at qgroup rescan and transaction commit time.
 */

/*
 * Special performance optimization for balance.
 *
 * For balance, we need to swap subtree of subvolume and reloc trees.
 * In theory, we need to trace all subtree blocks of both subvolume and reloc
 * trees, since their owner has changed during such swap.
 *
 * However since balance has ensured that both subtrees are containing the
 * same contents and have the same tree structures, such swap won't cause
 * qgroup number change.
 *
 * But there is a race window between subtree swap and transaction commit,
 * during that window, if we increase/decrease tree level or merge/split tree
 * blocks, we still need to trace the original subtrees.
 *
 * So for balance, we use a delayed subtree tracing, whose workflow is:
 *
 * 1) Record the subtree root block get swapped.
 *
 *    During subtree swap:
 *    O = Old tree blocks
 *    N = New tree blocks
 *          reloc tree                     subvolume tree X
 *             Root                               Root
 *            /    \                             /    \
 *          NA     OB                          OA      OB
 *        /  |     |  \                      /  |      |  \
 *      NC  ND     OE  OF                   OC  OD     OE  OF
 *
 *   In this case, NA and OA are going to be swapped, record (NA, OA) into
 *   subvolume tree X.
 *
 * 2) After subtree swap.
 *          reloc tree                     subvolume tree X
 *             Root                               Root
 *            /    \                             /    \
 *          OA     OB                          NA      OB
 *        /  |     |  \                      /  |      |  \
 *      OC  OD     OE  OF                   NC  ND     OE  OF
 *
 * 3a) COW happens for OB
 *     If we are going to COW tree block OB, we check OB's bytenr against
 *     tree X's swapped_blocks structure.
 *     If it doesn't fit any, nothing will happen.
 *
 * 3b) COW happens for NA
 *     Check NA's bytenr against tree X's swapped_blocks, and get a hit.
 *     Then we do subtree scan on both subtrees OA and NA.
 *     Resulting 6 tree blocks to be scanned (OA, OC, OD, NA, NC, ND).
 *
 *     Then no matter what we do to subvolume tree X, qgroup numbers will
 *     still be correct.
 *     Then NA's record gets removed from X's swapped_blocks.
 *
 * 4)  Transaction commit
 *     Any record in X's swapped_blocks gets removed, since there is no
 *     modification to the swapped subtrees, no need to trigger heavy qgroup
 *     subtree rescan for them.
 */

#define BTRFS_QGROUP_RUNTIME_FLAG_CANCEL_RESCAN		(1UL << 3)
#define BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING		(1UL << 4)

/*
 * Record a dirty extent, and info qgroup to update quota on it
 * TODO: Use kmem cache to alloc it.
 */
struct btrfs_qgroup_extent_record {
	struct rb_node node;
	u64 bytenr;
	u64 num_bytes;

	/*
	 * For qgroup reserved data space freeing.
	 *
	 * @data_rsv_refroot and @data_rsv will be recorded after
	 * BTRFS_ADD_DELAYED_EXTENT is called.
	 * And will be used to free reserved qgroup space at
	 * transaction commit time.
	 */
	u32 data_rsv;		/* reserved data space needs to be freed */
	u64 data_rsv_refroot;	/* which root the reserved data belongs to */
	struct ulist *old_roots;
};

struct btrfs_qgroup_swapped_block {
	struct rb_node node;

	int level;
	bool trace_leaf;

	/* bytenr/generation of the tree block in subvolume tree after swap */
	u64 subvol_bytenr;
	u64 subvol_generation;

	/* bytenr/generation of the tree block in reloc tree after swap */
	u64 reloc_bytenr;
	u64 reloc_generation;

	u64 last_snapshot;
	struct btrfs_key first_key;
};

/*
 * Qgroup reservation types:
 *
 * DATA:
 *	space reserved for data
 *
 * META_PERTRANS:
 * 	Space reserved for metadata (per-transaction)
 * 	Due to the fact that qgroup data is only updated at transaction commit
 * 	time, reserved space for metadata must be kept until transaction
 * 	commits.
 * 	Any metadata reserved that are used in btrfs_start_transaction() should
 * 	be of this type.
 *
 * META_PREALLOC:
 *	There are cases where metadata space is reserved before starting
 *	transaction, and then btrfs_join_transaction() to get a trans handle.
 *	Any metadata reserved for such usage should be of this type.
 *	And after join_transaction() part (or all) of such reservation should
 *	be converted into META_PERTRANS.
 */
enum btrfs_qgroup_rsv_type {
	BTRFS_QGROUP_RSV_DATA,
	BTRFS_QGROUP_RSV_META_PERTRANS,
	BTRFS_QGROUP_RSV_META_PREALLOC,
	BTRFS_QGROUP_RSV_LAST,
};

/*
 * Represents how many bytes we have reserved for this qgroup.
 *
 * Each type should have different reservation behavior.
 * E.g, data follows its io_tree flag modification, while
 * *currently* meta is just reserve-and-clear during transaction.
 *
 * TODO: Add new type for reservation which can survive transaction commit.
 * Current metadata reservation behavior is not suitable for such case.
 */
struct btrfs_qgroup_rsv {
	u64 values[BTRFS_QGROUP_RSV_LAST];
};

/*
 * one struct for each qgroup, organized in fs_info->qgroup_tree.
 */
struct btrfs_qgroup {
	u64 qgroupid;

	/*
	 * state
	 */
	u64 rfer;	/* referenced */
	u64 rfer_cmpr;	/* referenced compressed */
	u64 excl;	/* exclusive */
	u64 excl_cmpr;	/* exclusive compressed */

	/*
	 * limits
	 */
	u64 lim_flags;	/* which limits are set */
	u64 max_rfer;
	u64 max_excl;
	u64 rsv_rfer;
	u64 rsv_excl;

	/*
	 * reservation tracking
	 */
	struct btrfs_qgroup_rsv rsv;

	/*
	 * lists
	 */
	struct list_head groups;  /* groups this group is member of */
	struct list_head members; /* groups that are members of this group */
	struct list_head dirty;   /* dirty groups */
	struct rb_node node;	  /* tree of qgroups */

	/*
	 * temp variables for accounting operations
	 * Refer to qgroup_shared_accounting() for details.
	 */
	u64 old_refcnt;
	u64 new_refcnt;

	/*
	 * Sysfs kobjectid
	 */
	struct kobject kobj;
};

static inline u64 btrfs_qgroup_subvolid(u64 qgroupid)
{
	return (qgroupid & ((1ULL << BTRFS_QGROUP_LEVEL_SHIFT) - 1));
}

/*
 * For qgroup event trace points only
 */
#define QGROUP_RESERVE		(1<<0)
#define QGROUP_RELEASE		(1<<1)
#define QGROUP_FREE		(1<<2)

int btrfs_quota_enable(struct btrfs_fs_info *fs_info);
int btrfs_quota_disable(struct btrfs_fs_info *fs_info);
int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);
int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
				     bool interruptible);
int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
			      u64 dst);
int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
			      u64 dst);
int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid);
int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid);
int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
		       struct btrfs_qgroup_limit *limit);
int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info);
void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
struct btrfs_delayed_extent_op;

/*
 * Inform qgroup to trace one dirty extent, its info is recorded in @record.
 * So qgroup can account it at transaction committing time.
 *
 * No lock version, caller must acquire delayed ref lock and allocated memory,
 * then call btrfs_qgroup_trace_extent_post() after exiting lock context.
 *
 * Return 0 for success insert
 * Return >0 for existing record, caller can free @record safely.
 * Error is not possible
 */
int btrfs_qgroup_trace_extent_nolock(
		struct btrfs_fs_info *fs_info,
		struct btrfs_delayed_ref_root *delayed_refs,
		struct btrfs_qgroup_extent_record *record);

/*
 * Post handler after qgroup_trace_extent_nolock().
 *
 * NOTE: Current qgroup does the expensive backref walk at transaction
 * committing time with TRANS_STATE_COMMIT_DOING, this blocks incoming
 * new transaction.
 * This is designed to allow btrfs_find_all_roots() to get correct new_roots
 * result.
 *
 * However for old_roots there is no need to do backref walk at that time,
 * since we search commit roots to walk backref and result will always be
 * correct.
 *
 * Due to the nature of no lock version, we can't do backref there.
 * So we must call btrfs_qgroup_trace_extent_post() after exiting
 * spinlock context.
 *
 * TODO: If we can fix and prove btrfs_find_all_roots() can get correct result
 * using current root, then we can move all expensive backref walk out of
 * transaction committing, but not now as qgroup accounting will be wrong again.
 */
int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
				   struct btrfs_qgroup_extent_record *qrecord);

/*
 * Inform qgroup to trace one dirty extent, specified by @bytenr and
 * @num_bytes.
 * So qgroup can account it at commit trans time.
 *
 * Better encapsulated version, with memory allocation and backref walk for
 * commit roots.
 * So this can sleep.
 *
 * Return 0 if the operation is done.
 * Return <0 for error, like memory allocation failure or invalid parameter
 * (NULL trans)
 */
int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
			      u64 num_bytes, gfp_t gfp_flag);

/*
 * Inform qgroup to trace all leaf items of data
 *
 * Return 0 for success
 * Return <0 for error(ENOMEM)
 */
int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
				  struct extent_buffer *eb);
/*
 * Inform qgroup to trace a whole subtree, including all its child tree
 * blocks and data.
 * The root tree block is specified by @root_eb.
 *
 * Normally used by relocation(tree block swap) and subvolume deletion.
 *
 * Return 0 for success
 * Return <0 for error(ENOMEM or tree search error)
 */
int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
			       struct extent_buffer *root_eb,
			       u64 root_gen, int root_level);
int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
				u64 num_bytes, struct ulist *old_roots,
				struct ulist *new_roots);
int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans);
int btrfs_run_qgroups(struct btrfs_trans_handle *trans);
int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
			 u64 objectid, struct btrfs_qgroup_inherit *inherit);
void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
			       u64 ref_root, u64 num_bytes,
			       enum btrfs_qgroup_rsv_type type);

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
			       u64 rfer, u64 excl);
#endif

/* New io_tree based accurate qgroup reserve API */
int btrfs_qgroup_reserve_data(struct btrfs_inode *inode,
			struct extent_changeset **reserved, u64 start, u64 len);
int btrfs_qgroup_release_data(struct btrfs_inode *inode, u64 start, u64 len, u64 *released);
int btrfs_qgroup_free_data(struct btrfs_inode *inode,
			   struct extent_changeset *reserved, u64 start,
			   u64 len, u64 *freed);
int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
			      enum btrfs_qgroup_rsv_type type, bool enforce);
int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
				enum btrfs_qgroup_rsv_type type, bool enforce,
				bool noflush);
/* Reserve metadata space for pertrans and prealloc type */
static inline int btrfs_qgroup_reserve_meta_pertrans(struct btrfs_root *root,
				int num_bytes, bool enforce)
{
	return __btrfs_qgroup_reserve_meta(root, num_bytes,
					   BTRFS_QGROUP_RSV_META_PERTRANS,
					   enforce, false);
}
static inline int btrfs_qgroup_reserve_meta_prealloc(struct btrfs_root *root,
						     int num_bytes, bool enforce,
						     bool noflush)
{
	return __btrfs_qgroup_reserve_meta(root, num_bytes,
					   BTRFS_QGROUP_RSV_META_PREALLOC,
					   enforce, noflush);
}

void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
			     enum btrfs_qgroup_rsv_type type);

/* Free per-transaction meta reservation for error handling */
static inline void btrfs_qgroup_free_meta_pertrans(struct btrfs_root *root,
						   int num_bytes)
{
	__btrfs_qgroup_free_meta(root, num_bytes,
			BTRFS_QGROUP_RSV_META_PERTRANS);
}

/* Pre-allocated meta reservation can be freed at need */
static inline void btrfs_qgroup_free_meta_prealloc(struct btrfs_root *root,
						   int num_bytes)
{
	__btrfs_qgroup_free_meta(root, num_bytes,
			BTRFS_QGROUP_RSV_META_PREALLOC);
}

/*
 * Per-transaction meta reservation should be all freed at transaction commit
 * time
 */
void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root);

/*
 * Convert @num_bytes of META_PREALLOCATED reservation to META_PERTRANS.
 *
 * This is called when preallocated meta reservation needs to be used.
 * Normally after btrfs_join_transaction() call.
 */
void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes);

void btrfs_qgroup_check_reserved_leak(struct btrfs_inode *inode);

/* btrfs_qgroup_swapped_blocks related functions */
void btrfs_qgroup_init_swapped_blocks(
	struct btrfs_qgroup_swapped_blocks *swapped_blocks);

void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root);
int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
		struct btrfs_root *subvol_root,
		struct btrfs_block_group *bg,
		struct extent_buffer *subvol_parent, int subvol_slot,
		struct extent_buffer *reloc_parent, int reloc_slot,
		u64 last_snapshot);
int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
		struct btrfs_root *root, struct extent_buffer *eb);
void btrfs_qgroup_destroy_extent_records(struct btrfs_transaction *trans);
bool btrfs_check_quota_leak(struct btrfs_fs_info *fs_info);

#endif