zfs/include/sys/space_map.h

   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 */