freebsd-dev/sys/gnu/ext2fs/ext2_balloc.c
John Dyson c33a4405f7 Main code for the ext2fs filesystem. Please refer to the COPYRIGHT.INFO
file for GPL restrictions.  This code was ported to the BSD platform
by Godmar Back <gback@facility.cs.utah.edu> and specifically to FreeBSD
by John Dyson.  This code is still green and should be used with caution.
Additional changes to UFS necessary to make this code work will be commited
seperately.
Submitted by:	Godmar Back <gback@facility.cs.utah.edu>
Obtained from:	Lites/Mach4
1995-11-05 23:25:12 +00:00

336 lines
8.8 KiB
C

/*
* 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);
}