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have to release those buffers when reading indirect blocks
[unix-history] / usr / src / sys / ufs / ffs / ffs_balloc.c
/*
* Copyright (c) 1982, 1986, 1989 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* @(#)ffs_balloc.c 7.4 (Berkeley) %G%
*/
#include "param.h"
#include "systm.h"
#include "user.h"
#include "buf.h"
#include "proc.h"
#include "file.h"
#include "vnode.h"
#include "../ufs/inode.h"
#include "../ufs/fs.h"
/*
* Bmap defines the structure of file system storage
* by returning the physical block number on a device given the
* inode and the logical block number in a file.
* When convenient, it also leaves the physical
* block number of the next block of the file in rablock
* for use in read-ahead.
*/
bmap(ip, bn, bnp, rablockp, rasizep)
register struct inode *ip;
register daddr_t bn;
daddr_t *bnp;
daddr_t *rablockp;
int *rasizep;
{
register struct fs *fs;
register daddr_t nb;
struct buf *bp;
daddr_t *bap;
int i, j, sh;
int error;
if (bn < 0)
return (EFBIG);
fs = ip->i_fs;
/*
* The first NDADDR blocks are direct blocks
*/
if (bn < NDADDR) {
nb = ip->i_db[bn];
if (nb == 0) {
*bnp = (daddr_t)-1;
return (0);
}
if (rablockp && rasizep) {
if (bn < NDADDR - 1) {
*rablockp = fsbtodb(fs, ip->i_db[bn + 1]);
*rasizep = blksize(fs, ip, bn + 1);
} else {
*rablockp = 0;
*rasizep = 0;
}
}
*bnp = fsbtodb(fs, nb);
return (0);
}
/*
* Determine how many levels of indirection.
*/
sh = 1;
bn -= NDADDR;
for (j = NIADDR; j > 0; j--) {
sh *= NINDIR(fs);
if (bn < sh)
break;
bn -= sh;
}
if (j == 0)
return (EFBIG);
/*
* fetch the first indirect block
*/
nb = ip->i_ib[NIADDR - j];
if (nb == 0) {
*bnp = (daddr_t)-1;
return (0);
}
/*
* fetch through the indirect blocks
*/
for (; j <= NIADDR; j++) {
if (error = bread(ip->i_devvp, fsbtodb(fs, nb),
(int)fs->fs_bsize, &bp)) {
brelse(bp);
return (error);
}
bap = bp->b_un.b_daddr;
sh /= NINDIR(fs);
i = (bn / sh) % NINDIR(fs);
nb = bap[i];
if (nb == 0) {
*bnp = (daddr_t)-1;
brelse(bp);
return (0);
}
if (j < NIADDR)
brelse(bp);
}
/*
* calculate read-ahead.
*/
if (rablockp && rasizep) {
if (i < NINDIR(fs) - 1) {
*rablockp = fsbtodb(fs, bap[i + 1]);
*rasizep = fs->fs_bsize;
} else {
*rablockp = 0;
*rasizep = 0;
}
}
*bnp = fsbtodb(fs, nb);
brelse(bp);
return (0);
}
/*
* Balloc defines the structure of file system storage
* by returning the physical block number on a device given the
* inode and the logical block number in a file.
* When unallocated entries are found, new physical blocks
* are allocated.
*/
balloc(ip, bn, size, bnp, flags)
register struct inode *ip;
register daddr_t bn;
int size;
daddr_t *bnp;
int flags;
{
register struct fs *fs;
register daddr_t nb;
struct buf *bp, *nbp;
int osize, nsize, i, j, sh, error;
daddr_t lbn, *bap, pref, blkpref();
if (bn < 0)
return (EFBIG);
fs = ip->i_fs;
/*
* If the next write will extend the file into a new block,
* and the file is currently composed of a fragment
* this fragment has to be extended to be a full block.
*/
nb = lblkno(fs, ip->i_size);
if (nb < NDADDR && nb < bn) {
osize = blksize(fs, ip, nb);
if (osize < fs->fs_bsize && osize > 0) {
error = realloccg(ip, ip->i_db[nb],
blkpref(ip, nb, (int)nb, &ip->i_db[0]),
osize, (int)fs->fs_bsize, &bp);
if (error) {
*bnp = (daddr_t)-1;
return (error);
}
ip->i_size = (nb + 1) * fs->fs_bsize;
ip->i_db[nb] = dbtofsb(fs, bp->b_blkno);
ip->i_flag |= IUPD|ICHG;
bdwrite(bp);
}
}
/*
* The first NDADDR blocks are direct blocks
*/
if (bn < NDADDR) {
nb = ip->i_db[bn];
if (nb == 0 || ip->i_size < (bn + 1) * fs->fs_bsize) {
if (nb != 0) {
/* consider need to reallocate a frag */
osize = fragroundup(fs, blkoff(fs, ip->i_size));
nsize = fragroundup(fs, size);
if (nsize <= osize)
goto gotit;
error = realloccg(ip, nb,
blkpref(ip, bn, (int)bn, &ip->i_db[0]),
osize, nsize, &bp);
} else {
if (ip->i_size < (bn + 1) * fs->fs_bsize)
nsize = fragroundup(fs, size);
else
nsize = fs->fs_bsize;
error = alloc(ip,
blkpref(ip, bn, (int)bn, &ip->i_db[0]),
nsize, &bp, flags);
}
if (error) {
*bnp = (daddr_t)-1;
return (error);
}
nb = dbtofsb(fs, bp->b_blkno);
if ((ip->i_mode & IFMT) == IFDIR)
/*
* Write directory blocks synchronously
* so they never appear with garbage in
* them on the disk.
*
* NB: Should free space and return error
* if bwrite returns an error.
*/
error = bwrite(bp);
else
bdwrite(bp);
ip->i_db[bn] = nb;
ip->i_flag |= IUPD|ICHG;
}
gotit:
*bnp = fsbtodb(fs, nb);
return (0);
}
/*
* Determine how many levels of indirection.
*/
pref = 0;
sh = 1;
lbn = bn;
bn -= NDADDR;
for (j = NIADDR; j > 0; j--) {
sh *= NINDIR(fs);
if (bn < sh)
break;
bn -= sh;
}
if (j == 0)
return (EFBIG);
/*
* fetch the first indirect block
*/
nb = ip->i_ib[NIADDR - j];
if (nb == 0) {
pref = blkpref(ip, lbn, 0, (daddr_t *)0);
error = alloc(ip, pref, (int)fs->fs_bsize, &bp, B_CLRBUF);
if (error) {
*bnp = (daddr_t)-1;
return (error);
}
nb = dbtofsb(fs, bp->b_blkno);
/*
* Write synchronously so that indirect blocks
* never point at garbage.
*
* NB: Should free space and return error
* if bwrite returns an error.
*/
error = bwrite(bp);
ip->i_ib[NIADDR - j] = nb;
ip->i_flag |= IUPD|ICHG;
}
/*
* fetch through the indirect blocks
*/
for (; j <= NIADDR; j++) {
#ifdef SECSIZE
bp = bread(ip->i_dev, fsbtodb(fs, nb), (int)fs->fs_bsize,
fs->fs_dbsize);
#else SECSIZE
if (error = bread(ip->i_devvp, fsbtodb(fs, nb),
(int)fs->fs_bsize, &bp)) {
brelse(bp);
return (error);
}
bap = bp->b_un.b_daddr;
sh /= NINDIR(fs);
i = (bn / sh) % NINDIR(fs);
nb = bap[i];
if (nb == 0) {
if (pref == 0)
if (j < NIADDR)
pref = blkpref(ip, lbn, 0,
(daddr_t *)0);
else
pref = blkpref(ip, lbn, i, &bap[0]);
error = alloc(ip, pref, (int)fs->fs_bsize, &nbp,
(j < NIADDR) ? B_CLRBUF : flags);
if (error) {
brelse(bp);
*bnp = (daddr_t)-1;
return (error);
}
nb = dbtofsb(fs, nbp->b_blkno);
if (j < NIADDR || (ip->i_mode & IFMT) == IFDIR)
/*
* Write synchronously so indirect blocks
* never point at garbage and blocks
* in directories never contain garbage.
*
* NB: Should free space and return error
* if bwrite returns an error.
*/
error = bwrite(nbp);
else
bdwrite(nbp);
bap[i] = nb;
bdwrite(bp);
} else
brelse(bp);
}
*bnp = fsbtodb(fs, nb);
return (0);
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.