fs/freevxfs/vxfs_dir.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (c) 2000-2001 Christoph Hellwig.
   4  */
   5 #ifndef _VXFS_DIR_H_
   6 #define _VXFS_DIR_H_
   7
   8 /*
   9  * Veritas filesystem driver - directory structure.
  10  *
  11  * This file contains the definition of the vxfs directory format.
  12  */
  13
  14
  15 /*
  16  * VxFS directory block header.
  17  *
  18  * This entry is the head of every filesystem block in a directory.
  19  * It is used for free space management and additionally includes
  20  * a hash for speeding up directory search (lookup).
  21  *
  22  * The hash may be empty and in fact we do not use it all in the
  23  * Linux driver for now.
  24  */
  25 struct vxfs_dirblk {
  26         __fs16          d_free;         /* free space in dirblock */
  27         __fs16          d_nhash;        /* no of hash chains */
  28         __fs16          d_hash[];       /* hash chain */
  29 };
  30
  31 /*
  32  * VXFS_NAMELEN is the maximum length of the d_name field
  33  *      of an VxFS directory entry.
  34  */
  35 #define VXFS_NAMELEN    256
  36
  37 /*
  38  * VxFS directory entry.
  39  */
  40 struct vxfs_direct {
  41         __fs32          d_ino;                  /* inode number */
  42         __fs16          d_reclen;               /* record length */
  43         __fs16          d_namelen;              /* d_name length */
  44         __fs16          d_hashnext;             /* next hash entry */
  45         char            d_name[VXFS_NAMELEN];   /* name */
  46 };
  47
  48 /*
  49  * VXFS_DIRPAD defines the directory entry boundaries, is _must_ be
  50  *      a multiple of four.
  51  * VXFS_NAMEMIN is the length of a directory entry with a NULL d_name.
  52  * VXFS_DIRROUND is an internal macros that rounds a length to a value
  53  *      usable for directory sizes.
  54  * VXFS_DIRLEN calculates the directory entry size for an entry with
  55  *      a d_name with size len.
  56  */
  57 #define VXFS_DIRPAD             4
  58 #define VXFS_NAMEMIN            offsetof(struct vxfs_direct, d_name)
  59 #define VXFS_DIRROUND(len)      ((VXFS_DIRPAD + (len) - 1) & ~(VXFS_DIRPAD -1))
  60 #define VXFS_DIRLEN(len)        (VXFS_DIRROUND(VXFS_NAMEMIN + (len)))
  61
  62 /*
  63  * VXFS_DIRBLKOV is the overhead of a specific dirblock.
  64  */
  65 #define VXFS_DIRBLKOV(sbi, dbp) \
  66         ((sizeof(short) * fs16_to_cpu(sbi, dbp->d_nhash)) + 4)
  67
  68 #endif /* _VXFS_DIR_H_ */