include/zfs/zap_impl.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 (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
   9  */
  10
  11 #ifndef _SYS_ZAP_IMPL_H
  12 #define _SYS_ZAP_IMPL_H
  13
  14 #define ZAP_MAGIC 0x2F52AB2ABULL
  15
  16 #define ZAP_HASHBITS            28
  17 #define MZAP_ENT_LEN            64
  18 #define MZAP_NAME_LEN           (MZAP_ENT_LEN - 8 - 4 - 2)
  19 #define MZAP_MAX_BLKSHIFT       SPA_MAXBLOCKSHIFT
  20 #define MZAP_MAX_BLKSZ          (1 << MZAP_MAX_BLKSHIFT)
  21
  22 typedef struct mzap_ent_phys {
  23         uint64_t mze_value;
  24         uint32_t mze_cd;
  25         uint16_t mze_pad;       /* in case we want to chain them someday */
  26         char mze_name[MZAP_NAME_LEN];
  27 } mzap_ent_phys_t;
  28
  29 typedef struct mzap_phys {
  30         uint64_t mz_block_type; /* ZBT_MICRO */
  31         uint64_t mz_salt;
  32         uint64_t mz_pad[6];
  33         mzap_ent_phys_t mz_chunk[1];
  34         /* actually variable size depending on block size */
  35 } mzap_phys_t;
  36
  37 /*
  38  * The (fat) zap is stored in one object. It is an array of
  39  * 1<<FZAP_BLOCK_SHIFT byte blocks. The layout looks like one of:
  40  *
  41  * ptrtbl fits in first block:
  42  *      [zap_phys_t zap_ptrtbl_shift < 6] [zap_leaf_t] ...
  43  *
  44  * ptrtbl too big for first block:
  45  *      [zap_phys_t zap_ptrtbl_shift >= 6] [zap_leaf_t] [ptrtbl] ...
  46  *
  47  */
  48
  49 #define ZBT_LEAF                ((1ULL << 63) + 0)
  50 #define ZBT_HEADER              ((1ULL << 63) + 1)
  51 #define ZBT_MICRO               ((1ULL << 63) + 3)
  52 /* any other values are ptrtbl blocks */
  53
  54 /*
  55  * the embedded pointer table takes up half a block:
  56  * block size / entry size (2^3) / 2
  57  */
  58 #define ZAP_EMBEDDED_PTRTBL_SHIFT(zap) (FZAP_BLOCK_SHIFT(zap) - 3 - 1)
  59
  60 /*
  61  * The embedded pointer table starts half-way through the block.  Since
  62  * the pointer table itself is half the block, it starts at (64-bit)
  63  * word number (1<<ZAP_EMBEDDED_PTRTBL_SHIFT(zap)).
  64  */
  65 #define ZAP_EMBEDDED_PTRTBL_ENT(zap, idx) \
  66         ((uint64_t *)(zap)->zap_f.zap_phys) \
  67         [(idx) + (1<<ZAP_EMBEDDED_PTRTBL_SHIFT(zap))]
  68
  69 /*
  70  * TAKE NOTE:
  71  * If zap_phys_t is modified, zap_byteswap() must be modified.
  72  */
  73 typedef struct zap_phys {
  74         uint64_t zap_block_type;        /* ZBT_HEADER */
  75         uint64_t zap_magic;             /* ZAP_MAGIC */
  76
  77         struct zap_table_phys {
  78                 uint64_t zt_blk;        /* starting block number */
  79                 uint64_t zt_numblks;    /* number of blocks */
  80                 uint64_t zt_shift;      /* bits to index it */
  81                 uint64_t zt_nextblk;    /* next (larger) copy start block */
  82                 uint64_t zt_blks_copied; /* number source blocks copied */
  83         } zap_ptrtbl;
  84
  85         uint64_t zap_freeblk;           /* the next free block */
  86         uint64_t zap_num_leafs;         /* number of leafs */
  87         uint64_t zap_num_entries;       /* number of entries */
  88         uint64_t zap_salt;              /* salt to stir into hash function */
  89         uint64_t zap_normflags;         /* flags for u8_textprep_str() */
  90         uint64_t zap_flags;             /* zap_flag_t */
  91         /*
  92          * This structure is followed by padding, and then the embedded
  93          * pointer table.  The embedded pointer table takes up second
  94          * half of the block.  It is accessed using the
  95          * ZAP_EMBEDDED_PTRTBL_ENT() macro.
  96          */
  97 } zap_phys_t;
  98
  99 #endif /* _SYS_ZAP_IMPL_H */