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, 2018 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         /* object number: not needed but kept for backwards compatibility */
  59         uint64_t        smp_object;
  60
  61         /* length of the object in bytes */
  62         uint64_t        smp_length;
  63
  64         /* space allocated from the map */
  65         int64_t         smp_alloc;
  66
  67         /* reserved */
  68         uint64_t        smp_pad[5];
  69
  70         /*
  71          * The smp_histogram maintains a histogram of free regions. Each
  72          * bucket, smp_histogram[i], contains the number of free regions
  73          * whose size is:
  74          * 2^(i+sm_shift) <= size of free region in bytes < 2^(i+sm_shift+1)
  75          */
  76         uint64_t        smp_histogram[SPACE_MAP_HISTOGRAM_SIZE];
  77 } space_map_phys_t;
  78
  79 /*
  80  * The space map object defines a region of space, its size, how much is
  81  * allocated, and the on-disk object that stores this information.
  82  * Consumers of space maps may only access the members of this structure.
  83  *
  84  * Note: the space_map may not be accessed concurrently; consumers
  85  * must provide external locking if required.
  86  */
  87 typedef struct space_map {
  88         uint64_t        sm_start;       /* start of map */
  89         uint64_t        sm_size;        /* size of map */
  90         uint8_t         sm_shift;       /* unit shift */
  91         objset_t        *sm_os;         /* objset for this map */
  92         uint64_t        sm_object;      /* object id for this map */
  93         uint32_t        sm_blksz;       /* block size for space map */
  94         dmu_buf_t       *sm_dbuf;       /* space_map_phys_t dbuf */
  95         space_map_phys_t *sm_phys;      /* on-disk space map */
  96 } space_map_t;
  97
  98 /*
  99  * debug entry
 100  *
 101  *     2     2        10                     50
 102  *  +-----+-----+------------+----------------------------------+
 103  *  | 1 0 | act |  syncpass  |        txg (lower bits)          |
 104  *  +-----+-----+------------+----------------------------------+
 105  *   63 62 61 60 59        50 49                                0
 106  *
 107  *
 108  * one-word entry
 109  *
 110  *    1               47                   1           15
 111  *  +-----------------------------------------------------------+
 112  *  | 0 |   offset (sm_shift units)    | type |       run       |
 113  *  +-----------------------------------------------------------+
 114  *   63  62                          16   15   14               0
 115  *
 116  *
 117  * two-word entry
 118  *
 119  *     2     2               36                      24
 120  *  +-----+-----+---------------------------+-------------------+
 121  *  | 1 1 | pad |            run            |       vdev        |
 122  *  +-----+-----+---------------------------+-------------------+
 123  *   63 62 61 60 59                       24 23                 0
 124  *
 125  *     1                            63
 126  *  +------+----------------------------------------------------+
 127  *  | type |                      offset                        |
 128  *  +------+----------------------------------------------------+
 129  *     63   62                                                  0
 130  *
 131  * Note that a two-word entry will not straddle a block boundary.
 132  * If necessary, the last word of a block will be padded with a
 133  * debug entry (with act = syncpass = txg = 0).
 134  */
 135
 136 typedef enum {
 137         SM_ALLOC,
 138         SM_FREE
 139 } maptype_t;
 140
 141 typedef struct space_map_entry {
 142         maptype_t sme_type;
 143         uint32_t sme_vdev;      /* max is 2^24-1; SM_NO_VDEVID if not present */
 144         uint64_t sme_offset;    /* max is 2^63-1; units of sm_shift */
 145         uint64_t sme_run;       /* max is 2^36; units of sm_shift */
 146 } space_map_entry_t;
 147
 148 #define SM_NO_VDEVID    (1 << SPA_VDEVBITS)
 149
 150 /* one-word entry constants */
 151 #define SM_DEBUG_PREFIX 2
 152 #define SM_OFFSET_BITS  47
 153 #define SM_RUN_BITS     15
 154
 155 /* two-word entry constants */
 156 #define SM2_PREFIX      3
 157 #define SM2_OFFSET_BITS 63
 158 #define SM2_RUN_BITS    36
 159
 160 #define SM_PREFIX_DECODE(x)     BF64_DECODE(x, 62, 2)
 161 #define SM_PREFIX_ENCODE(x)     BF64_ENCODE(x, 62, 2)
 162
 163 #define SM_DEBUG_ACTION_DECODE(x)       BF64_DECODE(x, 60, 2)
 164 #define SM_DEBUG_ACTION_ENCODE(x)       BF64_ENCODE(x, 60, 2)
 165 #define SM_DEBUG_SYNCPASS_DECODE(x)     BF64_DECODE(x, 50, 10)
 166 #define SM_DEBUG_SYNCPASS_ENCODE(x)     BF64_ENCODE(x, 50, 10)
 167 #define SM_DEBUG_TXG_DECODE(x)          BF64_DECODE(x, 0, 50)
 168 #define SM_DEBUG_TXG_ENCODE(x)          BF64_ENCODE(x, 0, 50)
 169
 170 #define SM_OFFSET_DECODE(x)     BF64_DECODE(x, 16, SM_OFFSET_BITS)
 171 #define SM_OFFSET_ENCODE(x)     BF64_ENCODE(x, 16, SM_OFFSET_BITS)
 172 #define SM_TYPE_DECODE(x)       BF64_DECODE(x, 15, 1)
 173 #define SM_TYPE_ENCODE(x)       BF64_ENCODE(x, 15, 1)
 174 #define SM_RUN_DECODE(x)        (BF64_DECODE(x, 0, SM_RUN_BITS) + 1)
 175 #define SM_RUN_ENCODE(x)        BF64_ENCODE((x) - 1, 0, SM_RUN_BITS)
 176 #define SM_RUN_MAX              SM_RUN_DECODE(~0ULL)
 177 #define SM_OFFSET_MAX           SM_OFFSET_DECODE(~0ULL)
 178
 179 #define SM2_RUN_DECODE(x)       (BF64_DECODE(x, SPA_VDEVBITS, SM2_RUN_BITS) + 1)
 180 #define SM2_RUN_ENCODE(x)       BF64_ENCODE((x) - 1, SPA_VDEVBITS, SM2_RUN_BITS)
 181 #define SM2_VDEV_DECODE(x)      BF64_DECODE(x, 0, SPA_VDEVBITS)
 182 #define SM2_VDEV_ENCODE(x)      BF64_ENCODE(x, 0, SPA_VDEVBITS)
 183 #define SM2_TYPE_DECODE(x)      BF64_DECODE(x, SM2_OFFSET_BITS, 1)
 184 #define SM2_TYPE_ENCODE(x)      BF64_ENCODE(x, SM2_OFFSET_BITS, 1)
 185 #define SM2_OFFSET_DECODE(x)    BF64_DECODE(x, 0, SM2_OFFSET_BITS)
 186 #define SM2_OFFSET_ENCODE(x)    BF64_ENCODE(x, 0, SM2_OFFSET_BITS)
 187 #define SM2_RUN_MAX             SM2_RUN_DECODE(~0ULL)
 188 #define SM2_OFFSET_MAX          SM2_OFFSET_DECODE(~0ULL)
 189
 190 boolean_t sm_entry_is_debug(uint64_t e);
 191 boolean_t sm_entry_is_single_word(uint64_t e);
 192 boolean_t sm_entry_is_double_word(uint64_t e);
 193
 194 typedef int (*sm_cb_t)(space_map_entry_t *sme, void *arg);
 195
 196 int space_map_load(space_map_t *sm, range_tree_t *rt, maptype_t maptype);
 197 int space_map_load_length(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
 198     uint64_t length);
 199 int space_map_iterate(space_map_t *sm, uint64_t length,
 200     sm_cb_t callback, void *arg);
 201 int space_map_incremental_destroy(space_map_t *sm, sm_cb_t callback, void *arg,
 202     dmu_tx_t *tx);
 203
 204 void space_map_histogram_clear(space_map_t *sm);
 205 void space_map_histogram_add(space_map_t *sm, range_tree_t *rt,
 206     dmu_tx_t *tx);
 207
 208 uint64_t space_map_object(space_map_t *sm);
 209 int64_t space_map_allocated(space_map_t *sm);
 210 uint64_t space_map_length(space_map_t *sm);
 211
 212 void space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
 213     uint64_t vdev_id, dmu_tx_t *tx);
 214 uint64_t space_map_estimate_optimal_size(space_map_t *sm, range_tree_t *rt,
 215     uint64_t vdev_id);
 216 void space_map_truncate(space_map_t *sm, int blocksize, dmu_tx_t *tx);
 217 uint64_t space_map_alloc(objset_t *os, int blocksize, dmu_tx_t *tx);
 218 void space_map_free(space_map_t *sm, dmu_tx_t *tx);
 219 void space_map_free_obj(objset_t *os, uint64_t smobj, dmu_tx_t *tx);
 220
 221 int space_map_open(space_map_t **smp, objset_t *os, uint64_t object,
 222     uint64_t start, uint64_t size, uint8_t shift);
 223 void space_map_close(space_map_t *sm);
 224
 225 #ifdef  __cplusplus
 226 }
 227 #endif
 228
 229 #endif  /* _SYS_SPACE_MAP_H */