summaryrefslogtreecommitdiffstats
path: root/include/sys/space_map.h
blob: 7731a352f15d966f32f12281506b9ec65f827299 (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
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
 */

#ifndef _SYS_SPACE_MAP_H
#define	_SYS_SPACE_MAP_H

#include <sys/avl.h>
#include <sys/range_tree.h>
#include <sys/dmu.h>

#ifdef	__cplusplus
extern "C" {
#endif

/*
 * The size of the space map object has increased to include a histogram.
 * The SPACE_MAP_SIZE_V0 designates the original size and is used to
 * maintain backward compatibility.
 */
#define	SPACE_MAP_SIZE_V0	(3 * sizeof (uint64_t))
#define	SPACE_MAP_HISTOGRAM_SIZE	32

/*
 * The space_map_phys is the on-disk representation of the space map.
 * Consumers of space maps should never reference any of the members of this
 * structure directly. These members may only be updated in syncing context.
 *
 * Note the smp_object is no longer used but remains in the structure
 * for backward compatibility.
 */
typedef struct space_map_phys {
	/* object number: not needed but kept for backwards compatibility */
	uint64_t	smp_object;

	/* length of the object in bytes */
	uint64_t	smp_length;

	/* space allocated from the map */
	int64_t		smp_alloc;

	/* reserved */
	uint64_t	smp_pad[5];

	/*
	 * The smp_histogram maintains a histogram of free regions. Each
	 * bucket, smp_histogram[i], contains the number of free regions
	 * whose size is:
	 * 2^(i+sm_shift) <= size of free region in bytes < 2^(i+sm_shift+1)
	 */
	uint64_t	smp_histogram[SPACE_MAP_HISTOGRAM_SIZE];
} space_map_phys_t;

/*
 * The space map object defines a region of space, its size, how much is
 * allocated, and the on-disk object that stores this information.
 * Consumers of space maps may only access the members of this structure.
 *
 * Note: the space_map may not be accessed concurrently; consumers
 * must provide external locking if required.
 */
typedef struct space_map {
	uint64_t	sm_start;	/* start of map */
	uint64_t	sm_size;	/* size of map */
	uint8_t		sm_shift;	/* unit shift */
	objset_t	*sm_os;		/* objset for this map */
	uint64_t	sm_object;	/* object id for this map */
	uint32_t	sm_blksz;	/* block size for space map */
	dmu_buf_t	*sm_dbuf;	/* space_map_phys_t dbuf */
	space_map_phys_t *sm_phys;	/* on-disk space map */
} space_map_t;

/*
 * debug entry
 *
 *     2     2        10                     50
 *  +-----+-----+------------+----------------------------------+
 *  | 1 0 | act |  syncpass  |        txg (lower bits)          |
 *  +-----+-----+------------+----------------------------------+
 *   63 62 61 60 59        50 49                                0
 *
 *
 * one-word entry
 *
 *    1               47                   1           15
 *  +-----------------------------------------------------------+
 *  | 0 |   offset (sm_shift units)    | type |       run       |
 *  +-----------------------------------------------------------+
 *   63  62                          16   15   14               0
 *
 *
 * two-word entry
 *
 *     2     2               36                      24
 *  +-----+-----+---------------------------+-------------------+
 *  | 1 1 | pad |            run            |       vdev        |
 *  +-----+-----+---------------------------+-------------------+
 *   63 62 61 60 59                       24 23                 0
 *
 *     1                            63
 *  +------+----------------------------------------------------+
 *  | type |                      offset                        |
 *  +------+----------------------------------------------------+
 *     63   62                                                  0
 *
 * Note that a two-word entry will not straddle a block boundary.
 * If necessary, the last word of a block will be padded with a
 * debug entry (with act = syncpass = txg = 0).
 */

typedef enum {
	SM_ALLOC,
	SM_FREE
} maptype_t;

typedef struct space_map_entry {
	maptype_t sme_type;
	uint32_t sme_vdev;	/* max is 2^24-1; SM_NO_VDEVID if not present */
	uint64_t sme_offset;	/* max is 2^63-1; units of sm_shift */
	uint64_t sme_run;	/* max is 2^36; units of sm_shift */
} space_map_entry_t;

#define	SM_NO_VDEVID	(1 << SPA_VDEVBITS)

/* one-word entry constants */
#define	SM_DEBUG_PREFIX	2
#define	SM_OFFSET_BITS	47
#define	SM_RUN_BITS	15

/* two-word entry constants */
#define	SM2_PREFIX	3
#define	SM2_OFFSET_BITS	63
#define	SM2_RUN_BITS	36

#define	SM_PREFIX_DECODE(x)	BF64_DECODE(x, 62, 2)
#define	SM_PREFIX_ENCODE(x)	BF64_ENCODE(x, 62, 2)

#define	SM_DEBUG_ACTION_DECODE(x)	BF64_DECODE(x, 60, 2)
#define	SM_DEBUG_ACTION_ENCODE(x)	BF64_ENCODE(x, 60, 2)
#define	SM_DEBUG_SYNCPASS_DECODE(x)	BF64_DECODE(x, 50, 10)
#define	SM_DEBUG_SYNCPASS_ENCODE(x)	BF64_ENCODE(x, 50, 10)
#define	SM_DEBUG_TXG_DECODE(x)		BF64_DECODE(x, 0, 50)
#define	SM_DEBUG_TXG_ENCODE(x)		BF64_ENCODE(x, 0, 50)

#define	SM_OFFSET_DECODE(x)	BF64_DECODE(x, 16, SM_OFFSET_BITS)
#define	SM_OFFSET_ENCODE(x)	BF64_ENCODE(x, 16, SM_OFFSET_BITS)
#define	SM_TYPE_DECODE(x)	BF64_DECODE(x, 15, 1)
#define	SM_TYPE_ENCODE(x)	BF64_ENCODE(x, 15, 1)
#define	SM_RUN_DECODE(x)	(BF64_DECODE(x, 0, SM_RUN_BITS) + 1)
#define	SM_RUN_ENCODE(x)	BF64_ENCODE((x) - 1, 0, SM_RUN_BITS)
#define	SM_RUN_MAX		SM_RUN_DECODE(~0ULL)
#define	SM_OFFSET_MAX		SM_OFFSET_DECODE(~0ULL)

#define	SM2_RUN_DECODE(x)	(BF64_DECODE(x, SPA_VDEVBITS, SM2_RUN_BITS) + 1)
#define	SM2_RUN_ENCODE(x)	BF64_ENCODE((x) - 1, SPA_VDEVBITS, SM2_RUN_BITS)
#define	SM2_VDEV_DECODE(x)	BF64_DECODE(x, 0, SPA_VDEVBITS)
#define	SM2_VDEV_ENCODE(x)	BF64_ENCODE(x, 0, SPA_VDEVBITS)
#define	SM2_TYPE_DECODE(x)	BF64_DECODE(x, SM2_OFFSET_BITS, 1)
#define	SM2_TYPE_ENCODE(x)	BF64_ENCODE(x, SM2_OFFSET_BITS, 1)
#define	SM2_OFFSET_DECODE(x)	BF64_DECODE(x, 0, SM2_OFFSET_BITS)
#define	SM2_OFFSET_ENCODE(x)	BF64_ENCODE(x, 0, SM2_OFFSET_BITS)
#define	SM2_RUN_MAX		SM2_RUN_DECODE(~0ULL)
#define	SM2_OFFSET_MAX		SM2_OFFSET_DECODE(~0ULL)

boolean_t sm_entry_is_debug(uint64_t e);
boolean_t sm_entry_is_single_word(uint64_t e);
boolean_t sm_entry_is_double_word(uint64_t e);

typedef int (*sm_cb_t)(space_map_entry_t *sme, void *arg);

int space_map_load(space_map_t *sm, range_tree_t *rt, maptype_t maptype);
int space_map_load_length(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
    uint64_t length);
int space_map_iterate(space_map_t *sm, uint64_t length,
    sm_cb_t callback, void *arg);
int space_map_incremental_destroy(space_map_t *sm, sm_cb_t callback, void *arg,
    dmu_tx_t *tx);

boolean_t space_map_histogram_verify(space_map_t *sm, range_tree_t *rt);
void space_map_histogram_clear(space_map_t *sm);
void space_map_histogram_add(space_map_t *sm, range_tree_t *rt,
    dmu_tx_t *tx);

uint64_t space_map_object(space_map_t *sm);
int64_t space_map_allocated(space_map_t *sm);
uint64_t space_map_length(space_map_t *sm);

void space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
    uint64_t vdev_id, dmu_tx_t *tx);
uint64_t space_map_estimate_optimal_size(space_map_t *sm, range_tree_t *rt,
    uint64_t vdev_id);
void space_map_truncate(space_map_t *sm, int blocksize, dmu_tx_t *tx);
uint64_t space_map_alloc(objset_t *os, int blocksize, dmu_tx_t *tx);
void space_map_free(space_map_t *sm, dmu_tx_t *tx);
void space_map_free_obj(objset_t *os, uint64_t smobj, dmu_tx_t *tx);

int space_map_open(space_map_t **smp, objset_t *os, uint64_t object,
    uint64_t start, uint64_t size, uint8_t shift);
void space_map_close(space_map_t *sm);

#ifdef	__cplusplus
}
#endif

#endif	/* _SYS_SPACE_MAP_H */