text: /*
   *  modified for Lites 1.1
   *
   *  Aug 1995, Godmar Back (gback@cs.utah.edu)
   *  University of Utah, Department of Computer Science
   */
  /*
   * Copyright (c) 1982, 1986, 1989, 1993
   *	The Regents of the University of California.  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.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *	This product includes software developed by the University of
   *	California, Berkeley and its contributors.
   * 4. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
   *
   *	@(#)ffs_balloc.c	8.4 (Berkeley) 9/23/93
   */
  
  #if !defined(__FreeBSD__)
  #include "diagnostic.h"
  #endif
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/buf.h>
  #include <sys/proc.h>
  #include <sys/file.h>
  #include <sys/vnode.h>
  
  #include <vm/vm.h>
  
  #include <ufs/ufs/quota.h>
  #include <ufs/ufs/inode.h>
  #include <ufs/ufs/ufs_extern.h>
  
  #include <gnu/ext2fs/ext2_fs.h>
  #include <gnu/ext2fs/ext2_fs_sb.h>
  #include <gnu/ext2fs/fs.h>
  #include <gnu/ext2fs/ext2_extern.h>
  
  /*
   * Balloc defines the structure of file system storage
   * by allocating the physical blocks on a device given
   * the inode and the logical block number in a file.
   */
  int
  ext2_balloc(ip, bn, size, cred, bpp, flags)
  	register struct inode *ip;
  	register daddr_t bn;
  	int size;
  	struct ucred *cred;
  	struct buf **bpp;
  	int flags;
  {
  	register struct ext2_sb_info *fs;
  	register daddr_t nb;
  	struct buf *bp, *nbp;
  	struct vnode *vp = ITOV(ip);
  	struct indir indirs[NIADDR + 2];
  	daddr_t newb, lbn, *bap, pref;
  	int osize, nsize, num, i, error;
  /*
  ext2_debug("ext2_balloc called (%d, %d, %d)\n", 
  	ip->i_number, (int)bn, (int)size);
  */
  	*bpp = NULL;
  	if (bn < 0)
  		return (EFBIG);
  	fs = ip->i_e2fs;
  	lbn = bn;
  
  	/*
  	 * check if this is a sequential block allocation. 
  	 * If so, increment next_alloc fields to allow ext2_blkpref 
  	 * to make a good guess
  	 */
          if (lbn == ip->i_next_alloc_block + 1) {
  		ip->i_next_alloc_block++;
  		ip->i_next_alloc_goal++;
  	}
  
  	/*
  	 * The first NDADDR blocks are direct blocks
  	 */
  	if (bn < NDADDR) {
  		nb = ip->i_db[bn];
  		/* no new block is to be allocated, and no need to expand
  		   the file */
  		if (nb != 0 && ip->i_size >= (bn + 1) * fs->s_blocksize) {
  			error = bread(vp, bn, fs->s_blocksize, NOCRED, &bp);
  			if (error) {
  				brelse(bp);
  				return (error);
  			}
  			*bpp = bp;
  			return (0);
  		}
  		if (nb != 0) {
  			/*
  			 * Consider need to reallocate a fragment.
  			 */
  			osize = fragroundup(fs, blkoff(fs, ip->i_size));
  			nsize = fragroundup(fs, size);
  			if (nsize <= osize) {
  				error = bread(vp, bn, osize, NOCRED, &bp);
  				if (error) {
  					brelse(bp);
  					return (error);
  				}
  			} else {
  			/* Godmar thinks: this shouldn't happen w/o fragments */
  				printf("nsize %d(%d) > osize %d(%d) nb %d\n", 
  					(int)nsize, (int)size, (int)osize, 
  					(int)ip->i_size, (int)nb);
  				panic("ext2_balloc: "
  					"Something is terribly wrong\n");
  /*
   * please note there haven't been any changes from here on -
   * FFS seems to work.
   */
  			}
  		} else {
  			if (ip->i_size < (bn + 1) * fs->s_blocksize)
  				nsize = fragroundup(fs, size);
  			else
  				nsize = fs->s_blocksize;
  			error = ext2_alloc(ip, bn,
  			    ext2_blkpref(ip, bn, (int)bn, &ip->i_db[0], 0),
  			    nsize, cred, &newb);
  			if (error)
  				return (error);
  			bp = getblk(vp, bn, nsize, 0, 0);
  			bp->b_blkno = fsbtodb(fs, newb);
  			if (flags & B_CLRBUF)
  #if defined(__FreeBSD__)
  				vfs_bio_clrbuf(bp);
  #else
  				clrbuf(bp);
  #endif
  		}
  		ip->i_db[bn] = dbtofsb(fs, bp->b_blkno);
  		ip->i_flag |= IN_CHANGE | IN_UPDATE;
  		*bpp = bp;
  		return (0);
  	}
  	/*
  	 * Determine the number of levels of indirection.
  	 */
  	pref = 0;
  	if (error = ufs_getlbns(vp, bn, indirs, &num))
  		return(error);
  #if DIAGNOSTIC
  	if (num < 1)
  		panic ("ext2_balloc: ufs_bmaparray returned indirect block\n");
  #endif
  	/*
  	 * Fetch the first indirect block allocating if necessary.
  	 */
  	--num;
  	nb = ip->i_ib[indirs[0].in_off];
  	if (nb == 0) {
  #if 0
  		pref = ext2_blkpref(ip, lbn, 0, (daddr_t *)0, 0);
  #else
  		/* see the comment by ext2_blkpref. What we do here is
  		   to pretend that it'd be good for a block holding indirect
  		   pointers to be allocated near its predecessor in terms 
  		   of indirection, or the last direct block. 
  		   We shamelessly exploit the fact that i_ib immediately
  		   follows i_db. 
  		   Godmar thinks it make sense to allocate i_ib[0] immediately
  		   after i_db[11], but it's not utterly clear whether this also
  		   applies to i_ib[1] and i_ib[0]
  		*/
  
  		pref = ext2_blkpref(ip, lbn, indirs[0].in_off + 
  					     EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
  #endif
  	        if (error = ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize,
  		    cred, &newb))
  			return (error);
  		nb = newb;
  		bp = getblk(vp, indirs[1].in_lbn, fs->s_blocksize, 0, 0);
  		bp->b_blkno = fsbtodb(fs, newb);
  #if defined(__FreeBSD__)
  		vfs_bio_clrbuf(bp);
  #else
  		clrbuf(bp);
  #endif
  		/*
  		 * Write synchronously so that indirect blocks
  		 * never point at garbage.
  		 */
  		if (error = bwrite(bp)) {
  			ext2_blkfree(ip, nb, fs->s_blocksize);
  			return (error);
  		}
  		ip->i_ib[indirs[0].in_off] = newb;
  		ip->i_flag |= IN_CHANGE | IN_UPDATE;
  	}
  	/*
  	 * Fetch through the indirect blocks, allocating as necessary.
  	 */
  	for (i = 1;;) {
  		error = bread(vp,
  		    indirs[i].in_lbn, (int)fs->s_blocksize, NOCRED, &bp);
  		if (error) {
  			brelse(bp);
  			return (error);
  		}
  		bap = (daddr_t *)bp->b_data;
  		nb = bap[indirs[i].in_off];
  		if (i == num)
  			break;
  		i += 1;
  		if (nb != 0) {
  			brelse(bp);
  			continue;
  		}
  		if (pref == 0) 
  #if 1
  			/* see the comment above and by ext2_blkpref
  			 * I think this implements Linux policy, but
  			 * does it really make sense to allocate to
  			 * block containing pointers together ?
  			 * Also, will it ever succeed ?
  			 */
  			pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
  						bp->b_lblkno);
  #else
  			pref = ext2_blkpref(ip, lbn, 0, (daddr_t *)0, 0);
  #endif
  		if (error =
  		    ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize, cred, &newb)) {
  			brelse(bp);
  			return (error);
  		}
  		nb = newb;
  		nbp = getblk(vp, indirs[i].in_lbn, fs->s_blocksize, 0, 0);
  		nbp->b_blkno = fsbtodb(fs, nb);
  #if defined(__FreeBSD__)
  		vfs_bio_clrbuf(nbp);
  #else
  		clrbuf(nbp);
  #endif
  		/*
  		 * Write synchronously so that indirect blocks
  		 * never point at garbage.
  		 */
  		if (error = bwrite(nbp)) {
  			ext2_blkfree(ip, nb, fs->s_blocksize);
  			brelse(bp);
  			return (error);
  		}
  		bap[indirs[i - 1].in_off] = nb;
  		/*
  		 * If required, write synchronously, otherwise use
  		 * delayed write.
  		 */
  		if (flags & B_SYNC) {
  			bwrite(bp);
  		} else {
  			bdwrite(bp);
  		}
  	}
  	/*
  	 * Get the data block, allocating if necessary.
  	 */
  	if (nb == 0) {
  		pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0], 
  				bp->b_lblkno);
  		if (error = ext2_alloc(ip,
  		    lbn, pref, (int)fs->s_blocksize, cred, &newb)) {
  			brelse(bp);
  			return (error);
  		}
  		nb = newb;
  		nbp = getblk(vp, lbn, fs->s_blocksize, 0, 0);
  		nbp->b_blkno = fsbtodb(fs, nb);
  		if (flags & B_CLRBUF)
  #if defined(__FreeBSD__)
  			vfs_bio_clrbuf(nbp);
  #else
  			clrbuf(nbp);
  #endif
  		bap[indirs[i].in_off] = nb;
  		/*
  		 * If required, write synchronously, otherwise use
  		 * delayed write.
  		 */
  		if (flags & B_SYNC) {
  			bwrite(bp);
  		} else {
  			bdwrite(bp);
  		}
  		*bpp = nbp;
  		return (0);
  	}
  	brelse(bp);
  	if (flags & B_CLRBUF) {
  		error = bread(vp, lbn, (int)fs->s_blocksize, NOCRED, &nbp);
  		if (error) {
  			brelse(nbp);
  			return (error);
  		}
  	} else {
  		nbp = getblk(vp, lbn, fs->s_blocksize, 0, 0);
  		nbp->b_blkno = fsbtodb(fs, nb);
  	}
  	*bpp = nbp;
  	return (0);
  }
  