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/* Miscellaneous functions for fsck
Copyright (C) 1994 Free Software Foundation, Inc.
Written by Michael I. Bushnell.
This file is part of the GNU Hurd.
The GNU Hurd is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
The GNU Hurd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "fsck.h"
#include <fcntl.h>
#include <sys/file.h>
#include <unistd.h>
/* Read disk block ADDR into BUF of SIZE bytes. */
void
readblock (daddr_t addr, void *buf, size_t size)
{
if (lseek (readfd, addr * DEV_BSIZE, L_SET) == -1)
errexit ("CANNOT SEEK TO BLOCK %ld", addr);
if (read (readfd, buf, size) != size)
errexit ("CANNOT READ BLOCK %ld", addr);
}
/* Write disk block BLKNO from BUF of SIZE bytes. */
void
writeblock (daddr_t addr, void *buf, size_t size)
{
if (lseek (writefd, addr * DEV_BSIZE, L_SET) == -1)
errexit ("CANNOT SEEK TO BLOCK %ld", addr);
if (write (writefd, buf, size) != size)
errexit ("CANNOT READ BLOCK %ld", addr);
fsmodified = 1;
}
/* Read inode number INO into DINODE. */
void
getinode (ino_t ino, struct dinode *di)
{
daddr_t iblk;
char buf[sblock->fs_fsize];
iblk = ino_to_fsba (sblock, ino);
readblock (fsbtodb (sblock, iblk), buf, sblock->fs_fsize);
bcopy (buf + ino_to_fsbo (sblock, ino), di, sizeof (struct dinode));
}
/* Write inode number INO from DINODE. */
void
write_inode (ino_t ino, struct dinode *di)
{
daddr_t iblk;
char buf[sblock->fs_fsize];
iblk = ino_to_fsba (sblock, ino);
readblock (fsbtodb (sblock, iblk), buf, sblock->fs_fsize);
bcopy (di, buf + ino_to_fsbo (sblock, ino), sizeof (struct dinode));
writeblock (fsbtodb (sblock, iblk), buf, sblock->fs_fsize);
}
/* Clear inode number INO and zero DI. */
void
clear_inode (ino_t ino, struct dinode *di)
{
bzero (di, sizeof (struct dinode));
write_inode (ino, di);
}
/* Allocate and return a block and account for it in all the block
maps locally. Don't trust or change the disk block maps.
The block should be NFRAGS fragments long. */
daddr_t
allocblk (int nfrags)
{
daddr_t i;
int j, k;
if (nfrags <= 0 || nfrags > sblock->fs_frag)
return 0;
/* Examine each block of the filesystem. */
for (i = 0; i < maxfsblock - sblock->fs_frag; i += sblock->fs_frag)
{
/* For each piece of the block big enough to hold this frag... */
for (j = 0; j <= sblock->fs_frag - nfrags; j++)
{
/* For each frag of this piece... */
for (k = 0; k < nfrags; k++)
if (testbmap (i + j + k))
break;
/* If one of the frags was allocated... */
if (k < nfrags)
{
/* Skip at least that far (short cut) */
j += k;
continue;
}
/* It's free (at address i + j) */
/* Mark the frags allocated in our map */
for (k = 0; k < nfrags; k++)
setbmap (i + j + k);
return (i + j);
}
}
return 0;
}
/* Check if a block starting at BLK and extending for CNT
fragments is out of range; if it is, then return 1; otherwise return 0. */
int
check_range (daddr_t blk, int cnt)
{
int c;
if ((unsigned)(blk + cnt) > maxfsblock)
return 1;
c = dtog (sblock, blk);
if (blk < cgdmin (sblock, c))
{
if (blk + cnt > cgsblock (sblock, c))
return 1;
}
else
{
if (blk + cnt > cgbase (sblock, c + 1))
return 1;
}
return 0;
}
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