FreeBSD/Linux Kernel Cross Reference
sys/fs/freevxfs/vxfs_dir.h

     /*
      * Copyright (c) 2000-2001 Christoph Hellwig.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions, and the following disclaimer,
     *    without modification.
     * 2. The name of the author may not be used to endorse or promote products
     *    derived from this software without specific prior written permission.
     *
     * Alternatively, this software may be distributed under the terms of the
     * GNU General Public License ("GPL").
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
     * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     */
    #ifndef _VXFS_DIR_H_
    #define _VXFS_DIR_H_
    
    #ident "$Id: vxfs_dir.h,v 1.7 2001/05/21 15:48:26 hch Exp hch $"
    
    /*
     * Veritas filesystem driver - directory structure.
     *
     * This file contains the definition of the vxfs directory format.
     */
    
    
    /*
     * VxFS directory block header.
     *
     * This entry is the head of every filesystem block in a directory.
     * It is used for free space managment and additionally includes
     * a hash for speeding up directory search (lookup).
     *
     * The hash may be empty and in fact we do not use it all in the
     * Linux driver for now.
     */
    struct vxfs_dirblk {
            u_int16_t       d_free;         /* free space in dirblock */
            u_int16_t       d_nhash;        /* no of hash chains */
            u_int16_t       d_hash[1];      /* hash chain */
    };
    
    /*
     * VXFS_NAMELEN is the maximum length of the d_name field
     *      of an VxFS directory entry.
     */
    #define VXFS_NAMELEN    256
    
    /*
     * VxFS directory entry.
     */
    struct vxfs_direct {
            vx_ino_t        d_ino;                  /* inode number */
            u_int16_t       d_reclen;               /* record length */
            u_int16_t       d_namelen;              /* d_name length */
            u_int16_t       d_hashnext;             /* next hash entry */
            char            d_name[VXFS_NAMELEN];   /* name */
    };
    
    /*
     * VXFS_DIRPAD defines the directory entry boundaries, is _must_ be
     *      a multiple of four.
     * VXFS_NAMEMIN is the length of a directory entry with a NULL d_name.
     * VXFS_DIRROUND is an internal macros that rounds a length to a value
     *      usable for directory sizes.
     * VXFS_DIRLEN calculates the directory entry size for an entry with
     *      a d_name with size len.
     */
    #define VXFS_DIRPAD             4
    #define VXFS_NAMEMIN            ((int)((struct vxfs_direct *)0)->d_name)
    #define VXFS_DIRROUND(len)      ((VXFS_DIRPAD + (len) - 1) & ~(VXFS_DIRPAD -1))
    #define VXFS_DIRLEN(len)        (VXFS_DIRROUND(VXFS_NAMEMIN + (len)))
    
    /*
     * VXFS_DIRBLKOV is the overhead of a specific dirblock.
     */
    #define VXFS_DIRBLKOV(dbp)      ((sizeof(short) * dbp->d_nhash) + 4)
    
    #endif /* _VXFS_DIR_H_ */

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