xref: /illumos-gate/usr/src/uts/common/fs/zfs/sys/space_map.h (revision 6bb6b5762ca4b17cd5fb3c6c123f17489d5635aa)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*
27  * Copyright (c) 2012, 2015 by Delphix. All rights reserved.
28  */
29 
30 #ifndef _SYS_SPACE_MAP_H
31 #define	_SYS_SPACE_MAP_H
32 
33 #include <sys/avl.h>
34 #include <sys/range_tree.h>
35 #include <sys/dmu.h>
36 
37 #ifdef	__cplusplus
38 extern "C" {
39 #endif
40 
41 /*
42  * The size of the space map object has increased to include a histogram.
43  * The SPACE_MAP_SIZE_V0 designates the original size and is used to
44  * maintain backward compatibility.
45  */
46 #define	SPACE_MAP_SIZE_V0	(3 * sizeof (uint64_t))
47 #define	SPACE_MAP_HISTOGRAM_SIZE	32
48 
49 /*
50  * The space_map_phys is the on-disk representation of the space map.
51  * Consumers of space maps should never reference any of the members of this
52  * structure directly. These members may only be updated in syncing context.
53  *
54  * Note the smp_object is no longer used but remains in the structure
55  * for backward compatibility.
56  */
57 typedef struct space_map_phys {
58 	uint64_t	smp_object;	/* on-disk space map object */
59 	uint64_t	smp_objsize;	/* size of the object */
60 	uint64_t	smp_alloc;	/* space allocated from the map */
61 	uint64_t	smp_pad[5];	/* reserved */
62 
63 	/*
64 	 * The smp_histogram maintains a histogram of free regions. Each
65 	 * bucket, smp_histogram[i], contains the number of free regions
66 	 * whose size is:
67 	 * 2^(i+sm_shift) <= size of free region in bytes < 2^(i+sm_shift+1)
68 	 */
69 	uint64_t	smp_histogram[SPACE_MAP_HISTOGRAM_SIZE];
70 } space_map_phys_t;
71 
72 /*
73  * The space map object defines a region of space, its size, how much is
74  * allocated, and the on-disk object that stores this information.
75  * Consumers of space maps may only access the members of this structure.
76  *
77  * Note: the space_map may not be accessed concurrently; consumers
78  * must provide external locking if required.
79  */
80 typedef struct space_map {
81 	uint64_t	sm_start;	/* start of map */
82 	uint64_t	sm_size;	/* size of map */
83 	uint8_t		sm_shift;	/* unit shift */
84 	uint64_t	sm_length;	/* synced length */
85 	uint64_t	sm_alloc;	/* synced space allocated */
86 	objset_t	*sm_os;		/* objset for this map */
87 	uint64_t	sm_object;	/* object id for this map */
88 	uint32_t	sm_blksz;	/* block size for space map */
89 	dmu_buf_t	*sm_dbuf;	/* space_map_phys_t dbuf */
90 	space_map_phys_t *sm_phys;	/* on-disk space map */
91 } space_map_t;
92 
93 /*
94  * debug entry
95  *
96  *    1      3         10                     50
97  *  ,---+--------+------------+---------------------------------.
98  *  | 1 | action |  syncpass  |        txg (lower bits)         |
99  *  `---+--------+------------+---------------------------------'
100  *   63  62    60 59        50 49                               0
101  *
102  *
103  * non-debug entry
104  *
105  *    1               47                   1           15
106  *  ,-----------------------------------------------------------.
107  *  | 0 |   offset (sm_shift units)    | type |       run       |
108  *  `-----------------------------------------------------------'
109  *   63  62                          17   16   15               0
110  */
111 
112 /* All this stuff takes and returns bytes */
113 #define	SM_RUN_DECODE(x)	(BF64_DECODE(x, 0, 15) + 1)
114 #define	SM_RUN_ENCODE(x)	BF64_ENCODE((x) - 1, 0, 15)
115 #define	SM_TYPE_DECODE(x)	BF64_DECODE(x, 15, 1)
116 #define	SM_TYPE_ENCODE(x)	BF64_ENCODE(x, 15, 1)
117 #define	SM_OFFSET_DECODE(x)	BF64_DECODE(x, 16, 47)
118 #define	SM_OFFSET_ENCODE(x)	BF64_ENCODE(x, 16, 47)
119 #define	SM_DEBUG_DECODE(x)	BF64_DECODE(x, 63, 1)
120 #define	SM_DEBUG_ENCODE(x)	BF64_ENCODE(x, 63, 1)
121 
122 #define	SM_DEBUG_ACTION_DECODE(x)	BF64_DECODE(x, 60, 3)
123 #define	SM_DEBUG_ACTION_ENCODE(x)	BF64_ENCODE(x, 60, 3)
124 
125 #define	SM_DEBUG_SYNCPASS_DECODE(x)	BF64_DECODE(x, 50, 10)
126 #define	SM_DEBUG_SYNCPASS_ENCODE(x)	BF64_ENCODE(x, 50, 10)
127 
128 #define	SM_DEBUG_TXG_DECODE(x)		BF64_DECODE(x, 0, 50)
129 #define	SM_DEBUG_TXG_ENCODE(x)		BF64_ENCODE(x, 0, 50)
130 
131 #define	SM_RUN_MAX			SM_RUN_DECODE(~0ULL)
132 
133 typedef enum {
134 	SM_ALLOC,
135 	SM_FREE
136 } maptype_t;
137 
138 typedef int (*sm_cb_t)(maptype_t type, uint64_t offset, uint64_t size,
139     void *arg);
140 
141 int space_map_load(space_map_t *sm, range_tree_t *rt, maptype_t maptype);
142 int space_map_iterate(space_map_t *sm, sm_cb_t callback, void *arg);
143 
144 void space_map_histogram_clear(space_map_t *sm);
145 void space_map_histogram_add(space_map_t *sm, range_tree_t *rt,
146     dmu_tx_t *tx);
147 
148 void space_map_update(space_map_t *sm);
149 
150 uint64_t space_map_object(space_map_t *sm);
151 uint64_t space_map_allocated(space_map_t *sm);
152 uint64_t space_map_length(space_map_t *sm);
153 
154 void space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
155     dmu_tx_t *tx);
156 void space_map_truncate(space_map_t *sm, dmu_tx_t *tx);
157 uint64_t space_map_alloc(objset_t *os, dmu_tx_t *tx);
158 void space_map_free(space_map_t *sm, dmu_tx_t *tx);
159 void space_map_free_obj(objset_t *os, uint64_t smobj, dmu_tx_t *tx);
160 
161 int space_map_open(space_map_t **smp, objset_t *os, uint64_t object,
162     uint64_t start, uint64_t size, uint8_t shift);
163 void space_map_close(space_map_t *sm);
164 
165 int64_t space_map_alloc_delta(space_map_t *sm);
166 
167 #ifdef	__cplusplus
168 }
169 #endif
170 
171 #endif	/* _SYS_SPACE_MAP_H */
172