usr/src/sys/ufs/lfs/lfs_subr.c

/*
 * Copyright (c) 1991 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)lfs_subr.c  7.10 (Berkeley) %G%
 */

#include <sys/param.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/buf.h>

#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>

#include <ufs/lfs/lfs.h>
#include <ufs/lfs/lfs_extern.h>

/*
 * Return buffer with the contents of block "offset" from the beginning of
 * directory "ip".  If "res" is non-zero, fill it in with a pointer to the
 * remaining space in the directory.
 */
int
lfs_blkatoff(vp, offset, res, bpp)
        struct vnode *vp;
        off_t offset;
        char **res;
        struct buf **bpp;
{
        register struct lfs *fs;
        struct inode *ip;
        struct buf *bp;
        daddr_t lbn;
        int bsize, error;

        ip = VTOI(vp);
        fs = ip->i_lfs;
        lbn = lblkno(fs, offset);
        bsize = blksize(fs);

        *bpp = NULL;
        if (error = bread(vp, lbn, bsize, NOCRED, &bp)) {
                brelse(bp);
                return (error);
        }
        if (res)
                *res = bp->b_un.b_addr + blkoff(fs, offset);
        *bpp = bp;
        return (0);
}