LXR linux/fs/afs/xdr

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/* AFS fileserver XDR types
   3 *
   4 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
   5 * Written by David Howells (dhowells@redhat.com)
   6 */
   7
   8#ifndef XDR_FS_H
   9#define XDR_FS_H
  10
  11struct afs_xdr_AFSFetchStatus {
  12        __be32  if_version;
  13#define AFS_FSTATUS_VERSION     1
  14        __be32  type;
  15        __be32  nlink;
  16        __be32  size_lo;
  17        __be32  data_version_lo;
  18        __be32  author;
  19        __be32  owner;
  20        __be32  caller_access;
  21        __be32  anon_access;
  22        __be32  mode;
  23        __be32  parent_vnode;
  24        __be32  parent_unique;
  25        __be32  seg_size;
  26        __be32  mtime_client;
  27        __be32  mtime_server;
  28        __be32  group;
  29        __be32  sync_counter;
  30        __be32  data_version_hi;
  31        __be32  lock_count;
  32        __be32  size_hi;
  33        __be32  abort_code;
  34} __packed;
  35
  36#define AFS_DIR_HASHTBL_SIZE    128
  37#define AFS_DIR_DIRENT_SIZE     32
  38#define AFS_DIR_SLOTS_PER_BLOCK 64
  39#define AFS_DIR_BLOCK_SIZE      2048
  40#define AFS_DIR_BLOCKS_PER_PAGE (PAGE_SIZE / AFS_DIR_BLOCK_SIZE)
  41#define AFS_DIR_MAX_SLOTS       65536
  42#define AFS_DIR_BLOCKS_WITH_CTR 128
  43#define AFS_DIR_MAX_BLOCKS      1023
  44#define AFS_DIR_RESV_BLOCKS     1
  45#define AFS_DIR_RESV_BLOCKS0    13
  46
  47/*
  48 * Directory entry structure.
  49 */
  50union afs_xdr_dirent {
  51        struct {
  52                u8              valid;
  53                u8              unused[1];
  54                __be16          hash_next;
  55                __be32          vnode;
  56                __be32          unique;
  57                u8              name[];
  58                /* When determining the number of dirent slots needed to
  59                 * represent a directory entry, name should be assumed to be 16
  60                 * bytes, due to a now-standardised (mis)calculation, but it is
  61                 * in fact 20 bytes in size.  afs_dir_calc_slots() should be
  62                 * used for this.
  63                 *
  64                 * For names longer than (16 or) 20 bytes, extra slots should
  65                 * be annexed to this one using the extended_name format.
  66                 */
  67        } u;
  68        u8                      extended_name[32];
  69} __packed;
  70
  71/*
  72 * Directory block header (one at the beginning of every 2048-byte block).
  73 */
  74struct afs_xdr_dir_hdr {
  75        __be16          npages;
  76        __be16          magic;
  77#define AFS_DIR_MAGIC htons(1234)
  78        u8              reserved;
  79        u8              bitmap[8];
  80        u8              pad[19];
  81} __packed;
  82
  83/*
  84 * Directory block layout
  85 */
  86union afs_xdr_dir_block {
  87        struct afs_xdr_dir_hdr          hdr;
  88
  89        struct {
  90                struct afs_xdr_dir_hdr  hdr;
  91                u8                      alloc_ctrs[AFS_DIR_MAX_BLOCKS];
  92                __be16                  hashtable[AFS_DIR_HASHTBL_SIZE];
  93        } meta;
  94
  95        union afs_xdr_dirent    dirents[AFS_DIR_SLOTS_PER_BLOCK];
  96} __packed;
  97
  98/*
  99 * Directory layout on a linux VM page.
 100 */
 101struct afs_xdr_dir_page {
 102        union afs_xdr_dir_block blocks[AFS_DIR_BLOCKS_PER_PAGE];
 103};
 104
 105/*
 106 * Calculate the number of dirent slots required for any given name length.
 107 * The calculation is made assuming the part of the name in the first slot is
 108 * 16 bytes, rather than 20, but this miscalculation is now standardised.
 109 */
 110static inline unsigned int afs_dir_calc_slots(size_t name_len)
 111{
 112        name_len++; /* NUL-terminated */
 113        return 1 + ((name_len + 15) / AFS_DIR_DIRENT_SIZE);
 114}
 115
 116#endif /* XDR_FS_H */
 117