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      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, 2014 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 typedef struct space_map {
     78 	uint64_t	sm_start;	/* start of map */
     79 	uint64_t	sm_size;	/* size of map */
     80 	uint8_t		sm_shift;	/* unit shift */
     81 	uint64_t	sm_length;	/* synced length */
     82 	uint64_t	sm_alloc;	/* synced space allocated */
     83 	objset_t	*sm_os;		/* objset for this map */
     84 	uint64_t	sm_object;	/* object id for this map */
     85 	uint32_t	sm_blksz;	/* block size for space map */
     86 	dmu_buf_t	*sm_dbuf;	/* space_map_phys_t dbuf */
     87 	space_map_phys_t *sm_phys;	/* on-disk space map */
     88 	kmutex_t	*sm_lock;	/* pointer to lock that protects map */
     89 } space_map_t;
     90 
     91 /*
     92  * debug entry
     93  *
     94  *    1      3         10                     50
     95  *  ,---+--------+------------+---------------------------------.
     96  *  | 1 | action |  syncpass  |        txg (lower bits)         |
     97  *  `---+--------+------------+---------------------------------'
     98  *   63  62    60 59        50 49                               0
     99  *
    100  *
    101  * non-debug entry
    102  *
    103  *    1               47                   1           15
    104  *  ,-----------------------------------------------------------.
    105  *  | 0 |   offset (sm_shift units)    | type |       run       |
    106  *  `-----------------------------------------------------------'
    107  *   63  62                          17   16   15               0
    108  */
    109 
    110 /* All this stuff takes and returns bytes */
    111 #define	SM_RUN_DECODE(x)	(BF64_DECODE(x, 0, 15) + 1)
    112 #define	SM_RUN_ENCODE(x)	BF64_ENCODE((x) - 1, 0, 15)
    113 #define	SM_TYPE_DECODE(x)	BF64_DECODE(x, 15, 1)
    114 #define	SM_TYPE_ENCODE(x)	BF64_ENCODE(x, 15, 1)
    115 #define	SM_OFFSET_DECODE(x)	BF64_DECODE(x, 16, 47)
    116 #define	SM_OFFSET_ENCODE(x)	BF64_ENCODE(x, 16, 47)
    117 #define	SM_DEBUG_DECODE(x)	BF64_DECODE(x, 63, 1)
    118 #define	SM_DEBUG_ENCODE(x)	BF64_ENCODE(x, 63, 1)
    119 
    120 #define	SM_DEBUG_ACTION_DECODE(x)	BF64_DECODE(x, 60, 3)
    121 #define	SM_DEBUG_ACTION_ENCODE(x)	BF64_ENCODE(x, 60, 3)
    122 
    123 #define	SM_DEBUG_SYNCPASS_DECODE(x)	BF64_DECODE(x, 50, 10)
    124 #define	SM_DEBUG_SYNCPASS_ENCODE(x)	BF64_ENCODE(x, 50, 10)
    125 
    126 #define	SM_DEBUG_TXG_DECODE(x)		BF64_DECODE(x, 0, 50)
    127 #define	SM_DEBUG_TXG_ENCODE(x)		BF64_ENCODE(x, 0, 50)
    128 
    129 #define	SM_RUN_MAX			SM_RUN_DECODE(~0ULL)
    130 
    131 typedef enum {
    132 	SM_ALLOC,
    133 	SM_FREE
    134 } maptype_t;
    135 
    136 int space_map_load(space_map_t *sm, range_tree_t *rt, maptype_t maptype);
    137 
    138 void space_map_histogram_clear(space_map_t *sm);
    139 void space_map_histogram_add(space_map_t *sm, range_tree_t *rt,
    140     dmu_tx_t *tx);
    141 
    142 void space_map_update(space_map_t *sm);
    143 
    144 uint64_t space_map_object(space_map_t *sm);
    145 uint64_t space_map_allocated(space_map_t *sm);
    146 uint64_t space_map_length(space_map_t *sm);
    147 
    148 void space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
    149     dmu_tx_t *tx);
    150 void space_map_truncate(space_map_t *sm, dmu_tx_t *tx);
    151 uint64_t space_map_alloc(objset_t *os, dmu_tx_t *tx);
    152 void space_map_free(space_map_t *sm, dmu_tx_t *tx);
    153 
    154 int space_map_open(space_map_t **smp, objset_t *os, uint64_t object,
    155     uint64_t start, uint64_t size, uint8_t shift, kmutex_t *lp);
    156 void space_map_close(space_map_t *sm);
    157 
    158 int64_t space_map_alloc_delta(space_map_t *sm);
    159 
    160 #ifdef	__cplusplus
    161 }
    162 #endif
    163 
    164 #endif	/* _SYS_SPACE_MAP_H */
    165