struct super_block *sysv_read_super(struct super_block *sb,void *data,
int silent)
{
struct buffer_head *bh;
const char *found;
kdev_t dev = sb->s_dev;
struct inode *root_inode;
unsigned long blocknr;
if (1024 != sizeof (struct xenix_super_block))
panic("Xenix FS: bad super-block size");
if ((512 != sizeof (struct sysv4_super_block))
|| (512 != sizeof (struct sysv2_super_block)))
panic("SystemV FS: bad super-block size");
if (500 != sizeof (struct coh_super_block))
panic("Coherent FS: bad super-block size");
if (64 != sizeof (struct sysv_inode))
panic("sysv fs: bad i-node size");
MOD_INC_USE_COUNT;
lock_super(sb);
set_blocksize(dev,BLOCK_SIZE);
sb->sv_block_base = 0;
/* Try to read Xenix superblock */
if ((bh = bread(dev, 1, BLOCK_SIZE)) != NULL) {
if ((found = detect_xenix(sb,bh)) != NULL)
goto ok;
brelse(bh);
}
if ((bh = bread(dev, 0, BLOCK_SIZE)) != NULL) {
/* Try to recognize SystemV superblock */
if ((found = detect_sysv4(sb,bh)) != NULL)
goto ok;
if ((found = detect_sysv2(sb,bh)) != NULL)
goto ok;
/* Try to recognize Coherent superblock */
if ((found = detect_coherent(sb,bh)) != NULL)
goto ok;
brelse(bh);
}
/* Try to recognize SystemV superblock */
/* Offset by 1 track, i.e. most probably 9, 15, or 18 kilobytes. */
/* 2kB blocks with offset of 9 and 15 kilobytes are not supported. */
/* Maybe we should also check the device geometry ? */
{ static int offsets[] = { 9, 15, 18, };
int i;
for (i = 0; i < sizeof(offsets)/sizeof(offsets[0]); i++)
if ((bh = bread(dev, offsets[i], BLOCK_SIZE)) != NULL) {
/* Try to recognize SystemV superblock */
if ((found = detect_sysv4(sb,bh)) != NULL) {
if (sb->sv_block_size>BLOCK_SIZE && (offsets[i] % 2))
goto bad_shift;
sb->sv_block_base = (offsets[i] << sb->sv_block_size_dec_bits) >> sb->sv_block_size_inc_bits;
goto ok;
}
if ((found = detect_sysv2(sb,bh)) != NULL) {
if (sb->sv_block_size>BLOCK_SIZE && (offsets[i] % 2))
goto bad_shift;
sb->sv_block_base = (offsets[i] << sb->sv_block_size_dec_bits) >> sb->sv_block_size_inc_bits;
goto ok;
}
brelse(bh);
}
}
bad_shift:
sb->s_dev = 0;
unlock_super(sb);
if (!silent)
printk("VFS: unable to read Xenix/SystemV/Coherent superblock on device "
"%s\n", kdevname(dev));
failed:
MOD_DEC_USE_COUNT;
return NULL;
ok:
if (sb->sv_block_size >= BLOCK_SIZE) {
if (sb->sv_block_size != BLOCK_SIZE) {
brelse(bh);
set_blocksize(dev, sb->sv_block_size);
blocknr = (bh->b_blocknr << sb->sv_block_size_dec_bits) >> sb->sv_block_size_inc_bits;
if ((bh = bread(dev, blocknr, sb->sv_block_size)) == NULL)
goto bad_superblock;
}
switch (sb->sv_type) {
case FSTYPE_XENIX:
if (!detected_xenix(sb,bh,bh))
goto bad_superblock;
break;
case FSTYPE_SYSV4:
if (!detected_sysv4(sb,bh))
goto bad_superblock;
break;
case FSTYPE_SYSV2:
if (!detected_sysv2(sb,bh))
goto bad_superblock;
break;
default: goto bad_superblock;
goto superblock_ok;
bad_superblock:
brelse(bh);
sb->s_dev = 0;
unlock_super(sb);
printk("SysV FS: cannot read superblock in %d byte mode\n", sb->sv_block_size);
goto failed;
superblock_ok:
}
} else {
struct super_block *sysv_read_super(struct super_block *sb,void *data,
int silent)
{
struct buffer_head *bh;
const char *found;
int dev = sb->s_dev;
if (1024 != sizeof (struct xenix_super_block))
panic("Xenix FS: bad super-block size");
if ((512 != sizeof (struct sysv4_super_block))
|| (512 != sizeof (struct sysv2_super_block)))
panic("SystemV FS: bad super-block size");
if (500 != sizeof (struct coh_super_block))
panic("Coherent FS: bad super-block size");
if (64 != sizeof (struct sysv_inode))
panic("sysv fs: bad i-node size");
lock_super(sb);
sb->s_blocksize = BLOCK_SIZE; /* anything else not supported by the block device drivers */
sb->s_blocksize_bits = BLOCK_SIZE_BITS;
/* Try to read Xenix superblock */
if ((bh = bread(dev, 1, BLOCK_SIZE)) != NULL) {
if ((found = detect_xenix(sb,bh)) != NULL)
goto ok;
brelse(bh);
}
if ((bh = bread(dev, 0, BLOCK_SIZE)) != NULL) {
/* Try to recognize SystemV superblock */
if ((found = detect_sysv4(sb,bh)) != NULL)
goto ok;
if ((found = detect_sysv2(sb,bh)) != NULL)
goto ok;
/* Try to recognize Coherent superblock */
if ((found = detect_coherent(sb,bh)) != NULL)
goto ok;
brelse(bh);
}
/* Try to recognize SystemV2 superblock */
/* Offset by 1 track, i.e. most probably 9, 15, or 18 kilobytes. */
{ static int offsets[] = { 9, 15, 18, };
int i;
for (i = 0; i < sizeof(offsets)/sizeof(offsets[0]); i++)
if ((bh = bread(dev, offsets[i], BLOCK_SIZE)) != NULL) {
/* Try to recognize SystemV superblock */
if ((found = detect_sysv4(sb,bh)) != NULL) {
sb->sv_block_base = offsets[i];
goto ok;
}
if ((found = detect_sysv2(sb,bh)) != NULL) {
sb->sv_block_base = offsets[i];
goto ok;
}
brelse(bh);
}
}
sb->s_dev=0;
unlock_super(sb);
if (!silent)
printk("VFS: unable to read Xenix/SystemV/Coherent superblock on device %d/%d\n",MAJOR(dev),MINOR(dev));
return NULL;
ok:
sb->sv_ninodes = (sb->sv_firstdatazone - sb->sv_firstinodezone) << sb->sv_inodes_per_block_bits;
if (!silent)
printk("VFS: Found a %s FS (block size = %d) on device %d/%d\n",found,sb->sv_block_size,MAJOR(dev),MINOR(dev));
sb->s_magic = SYSV_MAGIC_BASE + sb->sv_type;
/* set up enough so that it can read an inode */
sb->s_dev = dev;
sb->s_op = &sysv_sops;
sb->s_mounted = iget(sb,SYSV_ROOT_INO);
unlock_super(sb);
if (!sb->s_mounted) {
brelse(bh);
sb->s_dev = 0;
printk("SysV FS: get root inode failed\n");
return NULL;
}
sb->s_dirt = 1; /* brelse(bh); occurs when the disk is unmounted. */
return sb;
}