fs/afs/xdr_fs.h

   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
  11 struct 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  */
  50 union 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  */
  74 struct 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  */
  86 union 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  */
 101 struct 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  */
 110 static 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 */