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/*
* linux/fs/sysv/inode.c
*
* minix/inode.c
* Copyright (C) 1991, 1992 Linus Torvalds
*
* xenix/inode.c
* Copyright (C) 1992 Doug Evans
*
* coh/inode.c
* Copyright (C) 1993 Pascal Haible, Bruno Haible
*
* sysv/inode.c
* Copyright (C) 1993 Paul B. Monday
*
* sysv/inode.c
* Copyright (C) 1993 Bruno Haible
* Copyright (C) 1997, 1998 Krzysztof G. Baranowski
*
* This file contains code for read/parsing the superblock.
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/sysv_fs.h>
#include <linux/init.h>
/*
* The following functions try to recognize specific filesystems.
*
* We recognize:
* - Xenix FS by its magic number.
* - SystemV FS by its magic number.
* - Coherent FS by its funny fname/fpack field.
* - SCO AFS by s_nfree == 0xffff
* - V7 FS has no distinguishing features.
*
* We discriminate among SystemV4 and SystemV2 FS by the assumption that
* the time stamp is not < 01-01-1980.
*/
enum {
JAN_1_1980 = (10*365 + 2) * 24 * 60 * 60
};
static void detected_xenix(struct super_block *sb)
{
struct buffer_head *bh1 = sb->sv_bh1;
struct buffer_head *bh2 = sb->sv_bh2;
struct xenix_super_block * sbd1;
struct xenix_super_block * sbd2;
if (bh1 != bh2)
sbd1 = sbd2 = (struct xenix_super_block *) bh1->b_data;
else {
/* block size = 512, so bh1 != bh2 */
sbd1 = (struct xenix_super_block *) bh1->b_data;
sbd2 = (struct xenix_super_block *) (bh2->b_data - 512);
}
sb->sv_link_max = XENIX_LINK_MAX;
sb->sv_fic_size = XENIX_NICINOD;
sb->sv_flc_size = XENIX_NICFREE;
sb->sv_sbd1 = (char *) sbd1;
sb->sv_sbd2 = (char *) sbd2;
sb->sv_sb_fic_count = &sbd1->s_ninode;
sb->sv_sb_fic_inodes = &sbd1->s_inode[0];
sb->sv_sb_total_free_inodes = &sbd2->s_tinode;
sb->sv_bcache_count = &sbd1->s_nfree;
sb->sv_bcache = &sbd1->s_free[0];
sb->sv_free_blocks = &sbd2->s_tfree;
sb->sv_sb_time = &sbd2->s_time;
sb->sv_firstdatazone = fs16_to_cpu(sb, sbd1->s_isize);
sb->sv_nzones = fs32_to_cpu(sb, sbd1->s_fsize);
}
static void detected_sysv4(struct super_block *sb)
{
struct sysv4_super_block * sbd;
struct buffer_head *bh1 = sb->sv_bh1;
struct buffer_head *bh2 = sb->sv_bh2;
if (bh1 == bh2)
sbd = (struct sysv4_super_block *) (bh1->b_data + BLOCK_SIZE/2);
else
sbd = (struct sysv4_super_block *) bh2->b_data;
sb->sv_link_max = SYSV_LINK_MAX;
sb->sv_fic_size = SYSV_NICINOD;
sb->sv_flc_size = SYSV_NICFREE;
sb->sv_sbd1 = (char *) sbd;
sb->sv_sbd2 = (char *) sbd;
sb->sv_sb_fic_count = &sbd->s_ninode;
sb->sv_sb_fic_inodes = &sbd->s_inode[0];
sb->sv_sb_total_free_inodes = &sbd->s_tinode;
sb->sv_bcache_count = &sbd->s_nfree;
sb->sv_bcache = &sbd->s_free[0];
sb->sv_free_blocks = &sbd->s_tfree;
sb->sv_sb_time = &sbd->s_time;
sb->sv_sb_state = &sbd->s_state;
sb->sv_firstdatazone = fs16_to_cpu(sb, sbd->s_isize);
sb->sv_nzones = fs32_to_cpu(sb, sbd->s_fsize);
}
static void detected_sysv2(struct super_block *sb)
{
struct sysv2_super_block * sbd;
struct buffer_head *bh1 = sb->sv_bh1;
struct buffer_head *bh2 = sb->sv_bh2;
if (bh1 == bh2)
sbd = (struct sysv2_super_block *) (bh1->b_data + BLOCK_SIZE/2);
else
sbd = (struct sysv2_super_block *) bh2->b_data;
sb->sv_link_max = SYSV_LINK_MAX;
sb->sv_fic_size = SYSV_NICINOD;
sb->sv_flc_size = SYSV_NICFREE;
sb->sv_sbd1 = (char *) sbd;
sb->sv_sbd2 = (char *) sbd;
sb->sv_sb_fic_count = &sbd->s_ninode;
sb->sv_sb_fic_inodes = &sbd->s_inode[0];
sb->sv_sb_total_free_inodes = &sbd->s_tinode;
sb->sv_bcache_count = &sbd->s_nfree;
sb->sv_bcache = &sbd->s_free[0];
sb->sv_free_blocks = &sbd->s_tfree;
sb->sv_sb_time = &sbd->s_time;
sb->sv_sb_state = &sbd->s_state;
sb->sv_firstdatazone = fs16_to_cpu(sb, sbd->s_isize);
sb->sv_nzones = fs32_to_cpu(sb, sbd->s_fsize);
}
static void detected_coherent(struct super_block *sb)
{
struct coh_super_block * sbd;
struct buffer_head *bh1 = sb->sv_bh1;
sbd = (struct coh_super_block *) bh1->b_data;
sb->sv_link_max = COH_LINK_MAX;
sb->sv_fic_size = COH_NICINOD;
sb->sv_flc_size = COH_NICFREE;
sb->sv_sbd1 = (char *) sbd;
sb->sv_sbd2 = (char *) sbd;
sb->sv_sb_fic_count = &sbd->s_ninode;
sb->sv_sb_fic_inodes = &sbd->s_inode[0];
sb->sv_sb_total_free_inodes = &sbd->s_tinode;
sb->sv_bcache_count = &sbd->s_nfree;
sb->sv_bcache = &sbd->s_free[0];
sb->sv_free_blocks = &sbd->s_tfree;
sb->sv_sb_time = &sbd->s_time;
sb->sv_firstdatazone = fs16_to_cpu(sb, sbd->s_isize);
sb->sv_nzones = fs32_to_cpu(sb, sbd->s_fsize);
}
static void detected_v7(struct super_block *sb)
{
struct buffer_head *bh2 = sb->sv_bh2;
struct v7_super_block *sbd = (struct v7_super_block *)bh2->b_data;
sb->sv_link_max = V7_LINK_MAX;
sb->sv_fic_size = V7_NICINOD;
sb->sv_flc_size = V7_NICFREE;
sb->sv_sbd1 = (char *)sbd;
sb->sv_sbd2 = (char *)sbd;
sb->sv_sb_fic_count = &sbd->s_ninode;
sb->sv_sb_fic_inodes = &sbd->s_inode[0];
sb->sv_sb_total_free_inodes = &sbd->s_tinode;
sb->sv_bcache_count = &sbd->s_nfree;
sb->sv_bcache = &sbd->s_free[0];
sb->sv_free_blocks = &sbd->s_tfree;
sb->sv_sb_time = &sbd->s_time;
sb->sv_firstdatazone = fs16_to_cpu(sb, sbd->s_isize);
sb->sv_nzones = fs32_to_cpu(sb, sbd->s_fsize);
}
static int detect_xenix (struct super_block *sb, struct buffer_head *bh)
{
struct xenix_super_block * sbd = (struct xenix_super_block *)bh->b_data;
if (sbd->s_magic == cpu_to_le32(0x2b5544))
sb->sv_bytesex = BYTESEX_LE;
else if (sbd->s_magic == cpu_to_be32(0x2b5544))
sb->sv_bytesex = BYTESEX_BE;
else
return 0;
if (sbd->s_type > 2 || sbd->s_type < 1)
return 0;
sb->sv_type = FSTYPE_XENIX;
return sbd->s_type;
}
static int detect_sysv (struct super_block *sb, struct buffer_head *bh)
{
/* All relevant fields are at the same offsets in R2 and R4 */
struct sysv4_super_block * sbd;
sbd = (struct sysv4_super_block *) (bh->b_data + BLOCK_SIZE/2);
if (sbd->s_magic == cpu_to_le32(0xfd187e20))
sb->sv_bytesex = BYTESEX_LE;
else if (sbd->s_magic == cpu_to_be32(0xfd187e20))
sb->sv_bytesex = BYTESEX_BE;
else
return 0;
if (fs16_to_cpu(sb, sbd->s_nfree) == 0xffff) {
sb->sv_type = FSTYPE_AFS;
if (!(sb->s_flags & MS_RDONLY)) {
printk("SysV FS: SCO EAFS on %s detected, "
"forcing read-only mode.\n",
bdevname(sb->s_dev));
sb->s_flags |= MS_RDONLY;
}
return sbd->s_type;
}
if (fs32_to_cpu(sb, sbd->s_time) < JAN_1_1980) {
/* this is likely to happen on SystemV2 FS */
if (sbd->s_type > 3 || sbd->s_type < 1)
return 0;
sb->sv_type = FSTYPE_SYSV2;
return sbd->s_type;
}
if ((sbd->s_type > 3 || sbd->s_type < 1) &&
(sbd->s_type > 0x30 || sbd->s_type < 0x10))
return 0;
/* On Interactive Unix (ISC) Version 4.0/3.x s_type field = 0x10,
0x20 or 0x30 indicates that symbolic links and the 14-character
filename limit is gone. Due to lack of information about this
feature read-only mode seems to be a reasonable approach... -KGB */
if (sbd->s_type >= 0x10) {
printk("SysV FS: can't handle long file names on %s, "
"forcing read-only mode.\n", kdevname(sb->s_dev));
sb->s_flags |= MS_RDONLY;
}
sb->sv_type = FSTYPE_SYSV4;
return sbd->s_type >= 0x10 ? (sbd->s_type >> 4) : sbd->s_type;
}
static int detect_coherent (struct super_block *sb, struct buffer_head *bh)
{
struct coh_super_block * sbd;
sbd = (struct coh_super_block *) (bh->b_data + BLOCK_SIZE/2);
if ((memcmp(sbd->s_fname,"noname",6) && memcmp(sbd->s_fname,"xxxxx ",6))
|| (memcmp(sbd->s_fpack,"nopack",6) && memcmp(sbd->s_fpack,"xxxxx\n",6)))
return 0;
sb->sv_bytesex = BYTESEX_PDP;
sb->sv_type = FSTYPE_COH;
return 1;
}
static int detect_sysv_odd(struct super_block *sb, struct buffer_head *bh)
{
int size = detect_sysv(sb, bh);
return size>2 ? 0 : size;
}
static struct {
int block;
int (*test)(struct super_block *, struct buffer_head *);
} flavours[] = {
{1, detect_xenix},
{0, detect_sysv},
{0, detect_coherent},
{9, detect_sysv_odd},
{15,detect_sysv_odd},
{18,detect_sysv},
};
static char *flavour_names[] = {
[FSTYPE_XENIX] "Xenix",
[FSTYPE_SYSV4] "SystemV",
[FSTYPE_SYSV2] "SystemV Release 2",
[FSTYPE_COH] "Coherent",
[FSTYPE_V7] "V7",
[FSTYPE_AFS] "AFS",
};
static void (*flavour_setup[])(struct super_block *) = {
[FSTYPE_XENIX] detected_xenix,
[FSTYPE_SYSV4] detected_sysv4,
[FSTYPE_SYSV2] detected_sysv2,
[FSTYPE_COH] detected_coherent,
[FSTYPE_V7] detected_v7,
[FSTYPE_AFS] detected_sysv4,
};
static int complete_read_super(struct super_block *sb, int silent, int size)
{
struct inode *root_inode;
char *found = flavour_names[sb->sv_type];
u_char n_bits = size+8;
int bsize = 1 << n_bits;
int bsize_4 = bsize >> 2;
sb->sv_firstinodezone = 2;
flavour_setup[sb->sv_type](sb);
sb->sv_truncate = 1;
sb->sv_ndatazones = sb->sv_nzones - sb->sv_firstdatazone;
sb->sv_inodes_per_block = bsize >> 6;
sb->sv_inodes_per_block_1 = (bsize >> 6)-1;
sb->sv_inodes_per_block_bits = n_bits-6;
sb->sv_ind_per_block = bsize_4;
sb->sv_ind_per_block_2 = bsize_4*bsize_4;
sb->sv_toobig_block = 10 + bsize_4 * (1 + bsize_4 * (1 + bsize_4));
sb->sv_ind_per_block_bits = n_bits-2;
sb->sv_ninodes = (sb->sv_firstdatazone - sb->sv_firstinodezone)
<< sb->sv_inodes_per_block_bits;
sb->s_blocksize = bsize;
sb->s_blocksize_bits = n_bits;
if (!silent)
printk("VFS: Found a %s FS (block size = %ld) on device %s\n",
found, sb->s_blocksize, bdevname(sb->s_dev));
sb->s_magic = SYSV_MAGIC_BASE + sb->sv_type;
/* set up enough so that it can read an inode */
sb->s_op = &sysv_sops;
root_inode = iget(sb,SYSV_ROOT_INO);
if (!root_inode || is_bad_inode(root_inode)) {
printk("SysV FS: get root inode failed\n");
return 0;
}
sb->s_root = d_alloc_root(root_inode);
if (!sb->s_root) {
iput(root_inode);
printk("SysV FS: get root dentry failed\n");
return 0;
}
if (sb->sv_truncate)
sb->s_root->d_op = &sysv_dentry_operations;
sb->s_flags |= MS_RDONLY;
sb->s_dirt = 1;
return 1;
}
static struct super_block *sysv_read_super(struct super_block *sb,
void *data, int silent)
{
struct buffer_head *bh1;
struct buffer_head *bh = NULL;
kdev_t dev = sb->s_dev;
unsigned long blocknr;
int size = 0;
int i;
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");
set_blocksize(dev,BLOCK_SIZE);
sb->s_blocksize = BLOCK_SIZE;
sb->sv_block_base = 0;
for (i = 0; i < sizeof(flavours)/sizeof(flavours[0]) && !size; i++) {
brelse(bh);
bh = sb_bread(sb, flavours[i].block);
if (!bh)
continue;
size = flavours[i].test(sb, bh);
}
if (!size)
goto Eunknown;
switch (size) {
case 1:
blocknr = bh->b_blocknr << 1;
brelse(bh);
set_blocksize(dev, 512);
sb->s_blocksize = 512;
bh1 = sb_bread(sb, blocknr);
bh = sb_bread(sb, blocknr + 1);
break;
case 2:
bh1 = bh;
break;
case 3:
blocknr = bh->b_blocknr >> 1;
brelse(bh);
set_blocksize(dev, 2048);
sb->s_blocksize = 2048;
bh1 = bh = sb_bread(sb, blocknr);
break;
default:
goto Ebadsize;
}
if (bh && bh1) {
sb->sv_bh1 = bh1;
sb->sv_bh2 = bh;
if (complete_read_super(sb, silent, size))
return sb;
}
brelse(bh1);
brelse(bh);
set_blocksize(sb->s_dev,BLOCK_SIZE);
printk("oldfs: cannot read superblock\n");
failed:
return NULL;
Eunknown:
brelse(bh);
if (!silent)
printk("VFS: unable to find oldfs superblock on device %s\n",
bdevname(dev));
goto failed;
Ebadsize:
brelse(bh);
if (!silent)
printk("VFS: oldfs: unsupported block size (%dKb)\n",
1<<(size-2));
goto failed;
}
static struct super_block *v7_read_super(struct super_block *sb,void *data,
int silent)
{
struct buffer_head *bh, *bh2 = NULL;
kdev_t dev = sb->s_dev;
struct v7_super_block *v7sb;
struct sysv_inode *v7i;
if (440 != sizeof (struct v7_super_block))
panic("V7 FS: bad super-block size");
if (64 != sizeof (struct sysv_inode))
panic("sysv fs: bad i-node size");
sb->sv_type = FSTYPE_V7;
sb->sv_bytesex = BYTESEX_PDP;
set_blocksize(dev, 512);
sb->s_blocksize = 512;
if ((bh = sb_bread(sb, 1)) == NULL) {
if (!silent)
printk("VFS: unable to read V7 FS superblock on "
"device %s.\n", bdevname(dev));
goto failed;
}
/* plausibility check on superblock */
v7sb = (struct v7_super_block *) bh->b_data;
if (fs16_to_cpu(sb,v7sb->s_nfree) > V7_NICFREE ||
fs16_to_cpu(sb,v7sb->s_ninode) > V7_NICINOD ||
fs32_to_cpu(sb,v7sb->s_time) == 0)
goto failed;
/* plausibility check on root inode: it is a directory,
with a nonzero size that is a multiple of 16 */
if ((bh2 = sb_bread(sb, 2)) == NULL)
goto failed;
v7i = (struct sysv_inode *)(bh2->b_data + 64);
if ((fs16_to_cpu(sb,v7i->i_mode) & ~0777) != S_IFDIR ||
(fs32_to_cpu(sb,v7i->i_size) == 0) ||
(fs32_to_cpu(sb,v7i->i_size) & 017) != 0)
goto failed;
brelse(bh2);
sb->sv_bh1 = bh;
sb->sv_bh2 = bh;
if (complete_read_super(sb, silent, 1))
return sb;
failed:
brelse(bh2);
brelse(bh);
return NULL;
}
/* Every kernel module contains stuff like this. */
static DECLARE_FSTYPE_DEV(sysv_fs_type, "sysv", sysv_read_super);
static DECLARE_FSTYPE_DEV(v7_fs_type, "v7", v7_read_super);
static int __init init_sysv_fs(void)
{
int err = register_filesystem(&sysv_fs_type);
if (!err)
err = register_filesystem(&v7_fs_type);
return err;
}
static void __exit exit_sysv_fs(void)
{
unregister_filesystem(&sysv_fs_type);
unregister_filesystem(&v7_fs_type);
}
EXPORT_NO_SYMBOLS;
module_init(init_sysv_fs)
module_exit(exit_sysv_fs)
MODULE_LICENSE("GPL");
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