include/zfs/zap_leaf.h

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7 /*
   8  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
   9  * Use is subject to license terms.
  10  */
  11
  12 #ifndef _SYS_ZAP_LEAF_H
  13 #define _SYS_ZAP_LEAF_H
  14
  15 #define ZAP_LEAF_MAGIC 0x2AB1EAF
  16
  17 /* chunk size = 24 bytes */
  18 #define ZAP_LEAF_CHUNKSIZE 24
  19
  20 /*
  21  * The amount of space within the chunk available for the array is:
  22  * chunk size - space for type (1) - space for next pointer (2)
  23  */
  24 #define ZAP_LEAF_ARRAY_BYTES (ZAP_LEAF_CHUNKSIZE - 3)
  25
  26 typedef enum zap_chunk_type {
  27         ZAP_CHUNK_FREE = 253,
  28         ZAP_CHUNK_ENTRY = 252,
  29         ZAP_CHUNK_ARRAY = 251,
  30         ZAP_CHUNK_TYPE_MAX = 250
  31 } zap_chunk_type_t;
  32
  33 /*
  34  * TAKE NOTE:
  35  * If zap_leaf_phys_t is modified, zap_leaf_byteswap() must be modified.
  36  */
  37 typedef struct zap_leaf_phys {
  38         struct zap_leaf_header {
  39                 uint64_t lh_block_type;         /* ZBT_LEAF */
  40                 uint64_t lh_pad1;
  41                 uint64_t lh_prefix;             /* hash prefix of this leaf */
  42                 uint32_t lh_magic;              /* ZAP_LEAF_MAGIC */
  43                 uint16_t lh_nfree;              /* number free chunks */
  44                 uint16_t lh_nentries;           /* number of entries */
  45                 uint16_t lh_prefix_len;         /* num bits used to id this */
  46
  47                 /* above is accessable to zap, below is zap_leaf private */
  48
  49                 uint16_t lh_freelist;           /* chunk head of free list */
  50                 uint8_t lh_pad2[12];
  51         } l_hdr; /* 2 24-byte chunks */
  52
  53         /*
  54          * The header is followed by a hash table with
  55          * ZAP_LEAF_HASH_NUMENTRIES(zap) entries.  The hash table is
  56          * followed by an array of ZAP_LEAF_NUMCHUNKS(zap)
  57          * zap_leaf_chunk structures.  These structures are accessed
  58          * with the ZAP_LEAF_CHUNK() macro.
  59          */
  60
  61         uint16_t l_hash[1];
  62 } zap_leaf_phys_t;
  63
  64 typedef union zap_leaf_chunk {
  65         struct zap_leaf_entry {
  66                 uint8_t le_type;                /* always ZAP_CHUNK_ENTRY */
  67                 uint8_t le_int_size;            /* size of ints */
  68                 uint16_t le_next;               /* next entry in hash chain */
  69                 uint16_t le_name_chunk;         /* first chunk of the name */
  70                 uint16_t le_name_length;        /* bytes in name, incl null */
  71                 uint16_t le_value_chunk;        /* first chunk of the value */
  72                 uint16_t le_value_length;       /* value length in ints */
  73                 uint32_t le_cd;         /* collision differentiator */
  74                 uint64_t le_hash;               /* hash value of the name */
  75         } l_entry;
  76         struct zap_leaf_array {
  77                 uint8_t la_type;                /* always ZAP_CHUNK_ARRAY */
  78                 union {
  79                         uint8_t la_array[ZAP_LEAF_ARRAY_BYTES];
  80                         uint64_t la_array64;
  81                 } __attribute__ ((packed));
  82                 uint16_t la_next;               /* next blk or CHAIN_END */
  83         } l_array;
  84         struct zap_leaf_free {
  85                 uint8_t lf_type;                /* always ZAP_CHUNK_FREE */
  86                 uint8_t lf_pad[ZAP_LEAF_ARRAY_BYTES];
  87                 uint16_t lf_next;       /* next in free list, or CHAIN_END */
  88         } l_free;
  89 } zap_leaf_chunk_t;
  90
  91 #endif /* _SYS_ZAP_LEAF_H */