[mirror_ubuntu-zesty-kernel.git] / fs / sysv / super.c

/*
 *  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/init.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>
#include "sysv.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 sysv_sb_info *sbi, unsigned *max_links)
{
	struct buffer_head *bh1 = sbi->s_bh1;
	struct buffer_head *bh2 = sbi->s_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);
	}

	*max_links = XENIX_LINK_MAX;
	sbi->s_fic_size = XENIX_NICINOD;
	sbi->s_flc_size = XENIX_NICFREE;
	sbi->s_sbd1 = (char *)sbd1;
	sbi->s_sbd2 = (char *)sbd2;
	sbi->s_sb_fic_count = &sbd1->s_ninode;
	sbi->s_sb_fic_inodes = &sbd1->s_inode[0];
	sbi->s_sb_total_free_inodes = &sbd2->s_tinode;
	sbi->s_bcache_count = &sbd1->s_nfree;
	sbi->s_bcache = &sbd1->s_free[0];
	sbi->s_free_blocks = &sbd2->s_tfree;
	sbi->s_sb_time = &sbd2->s_time;
	sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd1->s_isize);
	sbi->s_nzones = fs32_to_cpu(sbi, sbd1->s_fsize);
}

static void detected_sysv4(struct sysv_sb_info *sbi, unsigned *max_links)
{
	struct sysv4_super_block * sbd;
	struct buffer_head *bh1 = sbi->s_bh1;
	struct buffer_head *bh2 = sbi->s_bh2;

	if (bh1 == bh2)
		sbd = (struct sysv4_super_block *) (bh1->b_data + BLOCK_SIZE/2);
	else
		sbd = (struct sysv4_super_block *) bh2->b_data;

	*max_links = SYSV_LINK_MAX;
	sbi->s_fic_size = SYSV_NICINOD;
	sbi->s_flc_size = SYSV_NICFREE;
	sbi->s_sbd1 = (char *)sbd;
	sbi->s_sbd2 = (char *)sbd;
	sbi->s_sb_fic_count = &sbd->s_ninode;
	sbi->s_sb_fic_inodes = &sbd->s_inode[0];
	sbi->s_sb_total_free_inodes = &sbd->s_tinode;
	sbi->s_bcache_count = &sbd->s_nfree;
	sbi->s_bcache = &sbd->s_free[0];
	sbi->s_free_blocks = &sbd->s_tfree;
	sbi->s_sb_time = &sbd->s_time;
	sbi->s_sb_state = &sbd->s_state;
	sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
	sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}

static void detected_sysv2(struct sysv_sb_info *sbi, unsigned *max_links)
{
	struct sysv2_super_block *sbd;
	struct buffer_head *bh1 = sbi->s_bh1;
	struct buffer_head *bh2 = sbi->s_bh2;

	if (bh1 == bh2)
		sbd = (struct sysv2_super_block *) (bh1->b_data + BLOCK_SIZE/2);
	else
		sbd = (struct sysv2_super_block *) bh2->b_data;

	*max_links = SYSV_LINK_MAX;
	sbi->s_fic_size = SYSV_NICINOD;
	sbi->s_flc_size = SYSV_NICFREE;
	sbi->s_sbd1 = (char *)sbd;
	sbi->s_sbd2 = (char *)sbd;
	sbi->s_sb_fic_count = &sbd->s_ninode;
	sbi->s_sb_fic_inodes = &sbd->s_inode[0];
	sbi->s_sb_total_free_inodes = &sbd->s_tinode;
	sbi->s_bcache_count = &sbd->s_nfree;
	sbi->s_bcache = &sbd->s_free[0];
	sbi->s_free_blocks = &sbd->s_tfree;
	sbi->s_sb_time = &sbd->s_time;
	sbi->s_sb_state = &sbd->s_state;
	sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
	sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}

static void detected_coherent(struct sysv_sb_info *sbi, unsigned *max_links)
{
	struct coh_super_block * sbd;
	struct buffer_head *bh1 = sbi->s_bh1;

	sbd = (struct coh_super_block *) bh1->b_data;

	*max_links = COH_LINK_MAX;
	sbi->s_fic_size = COH_NICINOD;
	sbi->s_flc_size = COH_NICFREE;
	sbi->s_sbd1 = (char *)sbd;
	sbi->s_sbd2 = (char *)sbd;
	sbi->s_sb_fic_count = &sbd->s_ninode;
	sbi->s_sb_fic_inodes = &sbd->s_inode[0];
	sbi->s_sb_total_free_inodes = &sbd->s_tinode;
	sbi->s_bcache_count = &sbd->s_nfree;
	sbi->s_bcache = &sbd->s_free[0];
	sbi->s_free_blocks = &sbd->s_tfree;
	sbi->s_sb_time = &sbd->s_time;
	sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
	sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}

static void detected_v7(struct sysv_sb_info *sbi, unsigned *max_links)
{
	struct buffer_head *bh2 = sbi->s_bh2;
	struct v7_super_block *sbd = (struct v7_super_block *)bh2->b_data;

	*max_links = V7_LINK_MAX;
	sbi->s_fic_size = V7_NICINOD;
	sbi->s_flc_size = V7_NICFREE;
	sbi->s_sbd1 = (char *)sbd;
	sbi->s_sbd2 = (char *)sbd;
	sbi->s_sb_fic_count = &sbd->s_ninode;
	sbi->s_sb_fic_inodes = &sbd->s_inode[0];
	sbi->s_sb_total_free_inodes = &sbd->s_tinode;
	sbi->s_bcache_count = &sbd->s_nfree;
	sbi->s_bcache = &sbd->s_free[0];
	sbi->s_free_blocks = &sbd->s_tfree;
	sbi->s_sb_time = &sbd->s_time;
	sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
	sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}

static int detect_xenix(struct sysv_sb_info *sbi, struct buffer_head *bh)
{
	struct xenix_super_block *sbd = (struct xenix_super_block *)bh->b_data;
	if (*(__le32 *)&sbd->s_magic == cpu_to_le32(0x2b5544))
		sbi->s_bytesex = BYTESEX_LE;
	else if (*(__be32 *)&sbd->s_magic == cpu_to_be32(0x2b5544))
		sbi->s_bytesex = BYTESEX_BE;
	else
		return 0;
	switch (fs32_to_cpu(sbi, sbd->s_type)) {
	case 1:
		sbi->s_type = FSTYPE_XENIX;
		return 1;
	case 2:
		sbi->s_type = FSTYPE_XENIX;
		return 2;
	default:
		return 0;
	}
}

static int detect_sysv(struct sysv_sb_info *sbi, struct buffer_head *bh)
{
	struct super_block *sb = sbi->s_sb;
	/* All relevant fields are at the same offsets in R2 and R4 */
	struct sysv4_super_block * sbd;
	u32 type;

	sbd = (struct sysv4_super_block *) (bh->b_data + BLOCK_SIZE/2);
	if (*(__le32 *)&sbd->s_magic == cpu_to_le32(0xfd187e20))
		sbi->s_bytesex = BYTESEX_LE;
	else if (*(__be32 *)&sbd->s_magic == cpu_to_be32(0xfd187e20))
		sbi->s_bytesex = BYTESEX_BE;
	else
		return 0;

	type = fs32_to_cpu(sbi, sbd->s_type);
 
 	if (fs16_to_cpu(sbi, sbd->s_nfree) == 0xffff) {
 		sbi->s_type = FSTYPE_AFS;
		sbi->s_forced_ro = 1;
 		if (!(sb->s_flags & MS_RDONLY)) {
 			printk("SysV FS: SCO EAFS on %s detected, " 
 				"forcing read-only mode.\n", 
 				sb->s_id);
 		}
 		return type;
 	}
 
	if (fs32_to_cpu(sbi, sbd->s_time) < JAN_1_1980) {
		/* this is likely to happen on SystemV2 FS */
		if (type > 3 || type < 1)
			return 0;
		sbi->s_type = FSTYPE_SYSV2;
		return type;
	}
	if ((type > 3 || type < 1) && (type > 0x30 || 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 (type >= 0x10) {
		printk("SysV FS: can't handle long file names on %s, "
		       "forcing read-only mode.\n", sb->s_id);
		sbi->s_forced_ro = 1;
	}

	sbi->s_type = FSTYPE_SYSV4;
	return type >= 0x10 ? type >> 4 : type;
}

static int detect_coherent(struct sysv_sb_info *sbi, 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;
	sbi->s_bytesex = BYTESEX_PDP;
	sbi->s_type = FSTYPE_COH;
	return 1;
}

static int detect_sysv_odd(struct sysv_sb_info *sbi, struct buffer_head *bh)
{
	int size = detect_sysv(sbi, bh);

	return size>2 ? 0 : size;
}

static struct {
	int block;
	int (*test)(struct sysv_sb_info *, 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 sysv_sb_info *, unsigned *) = {
	[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 sysv_sb_info *sbi = SYSV_SB(sb);
	struct inode *root_inode;
	char *found = flavour_names[sbi->s_type];
	u_char n_bits = size+8;
	int bsize = 1 << n_bits;
	int bsize_4 = bsize >> 2;

	sbi->s_firstinodezone = 2;

	flavour_setup[sbi->s_type](sbi, &sb->s_max_links);
	
	sbi->s_truncate = 1;
	sbi->s_ndatazones = sbi->s_nzones - sbi->s_firstdatazone;
	sbi->s_inodes_per_block = bsize >> 6;
	sbi->s_inodes_per_block_1 = (bsize >> 6)-1;
	sbi->s_inodes_per_block_bits = n_bits-6;
	sbi->s_ind_per_block = bsize_4;
	sbi->s_ind_per_block_2 = bsize_4*bsize_4;
	sbi->s_toobig_block = 10 + bsize_4 * (1 + bsize_4 * (1 + bsize_4));
	sbi->s_ind_per_block_bits = n_bits-2;

	sbi->s_ninodes = (sbi->s_firstdatazone - sbi->s_firstinodezone)
		<< sbi->s_inodes_per_block_bits;

	if (!silent)
		printk("VFS: Found a %s FS (block size = %ld) on device %s\n",
		       found, sb->s_blocksize, sb->s_id);

	sb->s_magic = SYSV_MAGIC_BASE + sbi->s_type;
	/* set up enough so that it can read an inode */
	sb->s_op = &sysv_sops;
	if (sbi->s_forced_ro)
		sb->s_flags |= MS_RDONLY;
	if (sbi->s_truncate)
		sb->s_d_op = &sysv_dentry_operations;
	root_inode = sysv_iget(sb, SYSV_ROOT_INO);
	if (IS_ERR(root_inode)) {
		printk("SysV FS: get root inode failed\n");
		return 0;
	}
	sb->s_root = d_make_root(root_inode);
	if (!sb->s_root) {
		printk("SysV FS: get root dentry failed\n");
		return 0;
	}
	return 1;
}

static int sysv_fill_super(struct super_block *sb, void *data, int silent)
{
	struct buffer_head *bh1, *bh = NULL;
	struct sysv_sb_info *sbi;
	unsigned long blocknr;
	int size = 0, i;
	
	BUILD_BUG_ON(1024 != sizeof (struct xenix_super_block));
	BUILD_BUG_ON(512 != sizeof (struct sysv4_super_block));
	BUILD_BUG_ON(512 != sizeof (struct sysv2_super_block));
	BUILD_BUG_ON(500 != sizeof (struct coh_super_block));
	BUILD_BUG_ON(64 != sizeof (struct sysv_inode));

	sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
	if (!sbi)
		return -ENOMEM;

	sbi->s_sb = sb;
	sbi->s_block_base = 0;
	mutex_init(&sbi->s_lock);
	sb->s_fs_info = sbi;

	sb_set_blocksize(sb, BLOCK_SIZE);

	for (i = 0; i < ARRAY_SIZE(flavours) && !size; i++) {
		brelse(bh);
		bh = sb_bread(sb, flavours[i].block);
		if (!bh)
			continue;
		size = flavours[i].test(SYSV_SB(sb), bh);
	}

	if (!size)
		goto Eunknown;

	switch (size) {
		case 1:
			blocknr = bh->b_blocknr << 1;
			brelse(bh);
			sb_set_blocksize(sb, 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);
			sb_set_blocksize(sb, 2048);
			bh1 = bh = sb_bread(sb, blocknr);
			break;
		default:
			goto Ebadsize;
	}

	if (bh && bh1) {
		sbi->s_bh1 = bh1;
		sbi->s_bh2 = bh;
		if (complete_read_super(sb, silent, size))
			return 0;
	}

	brelse(bh1);
	brelse(bh);
	sb_set_blocksize(sb, BLOCK_SIZE);
	printk("oldfs: cannot read superblock\n");
failed:
	kfree(sbi);
	return -EINVAL;

Eunknown:
	brelse(bh);
	if (!silent)
		printk("VFS: unable to find oldfs superblock on device %s\n",
			sb->s_id);
	goto failed;
Ebadsize:
	brelse(bh);
	if (!silent)
		printk("VFS: oldfs: unsupported block size (%dKb)\n",
			1<<(size-2));
	goto failed;
}

static int v7_sanity_check(struct super_block *sb, struct buffer_head *bh)
{
	struct v7_super_block *v7sb;
	struct sysv_inode *v7i;
	struct buffer_head *bh2;
	struct sysv_sb_info *sbi;

	sbi = sb->s_fs_info;

	/* plausibility check on superblock */
	v7sb = (struct v7_super_block *) bh->b_data;
	if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE ||
	    fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD ||
	    fs32_to_cpu(sbi, v7sb->s_fsize) > V7_MAXSIZE)
		return 0;

	/* plausibility check on root inode: it is a directory,
	   with a nonzero size that is a multiple of 16 */
	bh2 = sb_bread(sb, 2);
	if (bh2 == NULL)
		return 0;

	v7i = (struct sysv_inode *)(bh2->b_data + 64);
	if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR ||
	    (fs32_to_cpu(sbi, v7i->i_size) == 0) ||
	    (fs32_to_cpu(sbi, v7i->i_size) & 017) ||
	    (fs32_to_cpu(sbi, v7i->i_size) > V7_NFILES *
	     sizeof(struct sysv_dir_entry))) {
		brelse(bh2);
		return 0;
	}

	brelse(bh2);
	return 1;
}

static int v7_fill_super(struct super_block *sb, void *data, int silent)
{
	struct sysv_sb_info *sbi;
	struct buffer_head *bh;

	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");

	sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
	if (!sbi)
		return -ENOMEM;

	sbi->s_sb = sb;
	sbi->s_block_base = 0;
	sbi->s_type = FSTYPE_V7;
	mutex_init(&sbi->s_lock);
	sb->s_fs_info = sbi;
	
	sb_set_blocksize(sb, 512);

	if ((bh = sb_bread(sb, 1)) == NULL) {
		if (!silent)
			printk("VFS: unable to read V7 FS superblock on "
			       "device %s.\n", sb->s_id);
		goto failed;
	}

	/* Try PDP-11 UNIX */
	sbi->s_bytesex = BYTESEX_PDP;
	if (v7_sanity_check(sb, bh))
		goto detected;

	/* Try PC/IX, v7/x86 */
	sbi->s_bytesex = BYTESEX_LE;
	if (v7_sanity_check(sb, bh))
		goto detected;

	goto failed;

detected:
	sbi->s_bh1 = bh;
	sbi->s_bh2 = bh;
	if (complete_read_super(sb, silent, 1))
		return 0;

failed:
	printk(KERN_ERR "VFS: could not find a valid V7 on %s.\n",
		sb->s_id);
	brelse(bh);
	kfree(sbi);
	return -EINVAL;
}

/* Every kernel module contains stuff like this. */

static struct dentry *sysv_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data)
{
	return mount_bdev(fs_type, flags, dev_name, data, sysv_fill_super);
}

static struct dentry *v7_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data)
{
	return mount_bdev(fs_type, flags, dev_name, data, v7_fill_super);
}

static struct file_system_type sysv_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "sysv",
	.mount		= sysv_mount,
	.kill_sb	= kill_block_super,
	.fs_flags	= FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("sysv");

static struct file_system_type v7_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "v7",
	.mount		= v7_mount,
	.kill_sb	= kill_block_super,
	.fs_flags	= FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("v7");
MODULE_ALIAS("v7");

static int __init init_sysv_fs(void)
{
	int error;

	error = sysv_init_icache();
	if (error)
		goto out;
	error = register_filesystem(&sysv_fs_type);
	if (error)
		goto destroy_icache;
	error = register_filesystem(&v7_fs_type);
	if (error)
		goto unregister;
	return 0;

unregister:
	unregister_filesystem(&sysv_fs_type);
destroy_icache:
	sysv_destroy_icache();
out:
	return error;
}

static void __exit exit_sysv_fs(void)
{
	unregister_filesystem(&sysv_fs_type);
	unregister_filesystem(&v7_fs_type);
	sysv_destroy_icache();
}

module_init(init_sysv_fs)
module_exit(exit_sysv_fs)
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/sysv/inode.c
	3	*
	4	* minix/inode.c
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	*
	7	* xenix/inode.c
	8	* Copyright (C) 1992 Doug Evans
	9	*
	10	* coh/inode.c
	11	* Copyright (C) 1993 Pascal Haible, Bruno Haible
	12	*
	13	* sysv/inode.c
	14	* Copyright (C) 1993 Paul B. Monday
	15	*
	16	* sysv/inode.c
	17	* Copyright (C) 1993 Bruno Haible
	18	* Copyright (C) 1997, 1998 Krzysztof G. Baranowski
	19	*
	20	* This file contains code for read/parsing the superblock.
	21	*/
	22
	23	#include <linux/module.h>
	24	#include <linux/init.h>
	25	#include <linux/slab.h>
	26	#include <linux/buffer_head.h>
	27	#include "sysv.h"
	28
	29	/*
	30	* The following functions try to recognize specific filesystems.
	31	*
	32	* We recognize:
	33	* - Xenix FS by its magic number.
	34	* - SystemV FS by its magic number.
	35	* - Coherent FS by its funny fname/fpack field.
	36	* - SCO AFS by s_nfree == 0xffff
	37	* - V7 FS has no distinguishing features.
	38	*
	39	* We discriminate among SystemV4 and SystemV2 FS by the assumption that
	40	* the time stamp is not < 01-01-1980.
	41	*/
	42
	43	enum {
	44	JAN_1_1980 = (10365 + 2) 24 * 60 * 60
	45	};
	46
8de52778	47	static void detected_xenix(struct sysv_sb_info sbi, unsigned max_links)
1da177e4 LT	48	{
	49	struct buffer_head *bh1 = sbi->s_bh1;
	50	struct buffer_head *bh2 = sbi->s_bh2;
	51	struct xenix_super_block * sbd1;
	52	struct xenix_super_block * sbd2;
	53
	54	if (bh1 != bh2)
	55	sbd1 = sbd2 = (struct xenix_super_block *) bh1->b_data;
	56	else {
	57	/* block size = 512, so bh1 != bh2 */
	58	sbd1 = (struct xenix_super_block *) bh1->b_data;
	59	sbd2 = (struct xenix_super_block *) (bh2->b_data - 512);
	60	}
	61
8de52778	62	*max_links = XENIX_LINK_MAX;
1da177e4 LT	63	sbi->s_fic_size = XENIX_NICINOD;
	64	sbi->s_flc_size = XENIX_NICFREE;
	65	sbi->s_sbd1 = (char *)sbd1;
	66	sbi->s_sbd2 = (char *)sbd2;
	67	sbi->s_sb_fic_count = &sbd1->s_ninode;
	68	sbi->s_sb_fic_inodes = &sbd1->s_inode[0];
	69	sbi->s_sb_total_free_inodes = &sbd2->s_tinode;
	70	sbi->s_bcache_count = &sbd1->s_nfree;
	71	sbi->s_bcache = &sbd1->s_free[0];
	72	sbi->s_free_blocks = &sbd2->s_tfree;
	73	sbi->s_sb_time = &sbd2->s_time;
	74	sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd1->s_isize);
	75	sbi->s_nzones = fs32_to_cpu(sbi, sbd1->s_fsize);
	76	}
	77
8de52778	78	static void detected_sysv4(struct sysv_sb_info sbi, unsigned max_links)
1da177e4 LT	79	{
	80	struct sysv4_super_block * sbd;
	81	struct buffer_head *bh1 = sbi->s_bh1;
	82	struct buffer_head *bh2 = sbi->s_bh2;
	83
	84	if (bh1 == bh2)
	85	sbd = (struct sysv4_super_block *) (bh1->b_data + BLOCK_SIZE/2);
	86	else
	87	sbd = (struct sysv4_super_block *) bh2->b_data;
	88
8de52778	89	*max_links = SYSV_LINK_MAX;
1da177e4 LT	90	sbi->s_fic_size = SYSV_NICINOD;
	91	sbi->s_flc_size = SYSV_NICFREE;
	92	sbi->s_sbd1 = (char *)sbd;
	93	sbi->s_sbd2 = (char *)sbd;
	94	sbi->s_sb_fic_count = &sbd->s_ninode;
	95	sbi->s_sb_fic_inodes = &sbd->s_inode[0];
	96	sbi->s_sb_total_free_inodes = &sbd->s_tinode;
	97	sbi->s_bcache_count = &sbd->s_nfree;
	98	sbi->s_bcache = &sbd->s_free[0];
	99	sbi->s_free_blocks = &sbd->s_tfree;
	100	sbi->s_sb_time = &sbd->s_time;
	101	sbi->s_sb_state = &sbd->s_state;
	102	sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
	103	sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
	104	}
	105
8de52778	106	static void detected_sysv2(struct sysv_sb_info sbi, unsigned max_links)
1da177e4 LT	107	{
	108	struct sysv2_super_block *sbd;
	109	struct buffer_head *bh1 = sbi->s_bh1;
	110	struct buffer_head *bh2 = sbi->s_bh2;
	111
	112	if (bh1 == bh2)
	113	sbd = (struct sysv2_super_block *) (bh1->b_data + BLOCK_SIZE/2);
	114	else
	115	sbd = (struct sysv2_super_block *) bh2->b_data;
	116
8de52778	117	*max_links = SYSV_LINK_MAX;
1da177e4 LT	118	sbi->s_fic_size = SYSV_NICINOD;
	119	sbi->s_flc_size = SYSV_NICFREE;
	120	sbi->s_sbd1 = (char *)sbd;
	121	sbi->s_sbd2 = (char *)sbd;
	122	sbi->s_sb_fic_count = &sbd->s_ninode;
	123	sbi->s_sb_fic_inodes = &sbd->s_inode[0];
	124	sbi->s_sb_total_free_inodes = &sbd->s_tinode;
	125	sbi->s_bcache_count = &sbd->s_nfree;
	126	sbi->s_bcache = &sbd->s_free[0];
	127	sbi->s_free_blocks = &sbd->s_tfree;
	128	sbi->s_sb_time = &sbd->s_time;
	129	sbi->s_sb_state = &sbd->s_state;
	130	sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
	131	sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
	132	}
	133
8de52778	134	static void detected_coherent(struct sysv_sb_info sbi, unsigned max_links)
1da177e4 LT	135	{
	136	struct coh_super_block * sbd;
	137	struct buffer_head *bh1 = sbi->s_bh1;
	138
	139	sbd = (struct coh_super_block *) bh1->b_data;
	140
8de52778	141	*max_links = COH_LINK_MAX;
1da177e4 LT	142	sbi->s_fic_size = COH_NICINOD;
	143	sbi->s_flc_size = COH_NICFREE;
	144	sbi->s_sbd1 = (char *)sbd;
	145	sbi->s_sbd2 = (char *)sbd;
	146	sbi->s_sb_fic_count = &sbd->s_ninode;
	147	sbi->s_sb_fic_inodes = &sbd->s_inode[0];
	148	sbi->s_sb_total_free_inodes = &sbd->s_tinode;
	149	sbi->s_bcache_count = &sbd->s_nfree;
	150	sbi->s_bcache = &sbd->s_free[0];
	151	sbi->s_free_blocks = &sbd->s_tfree;
	152	sbi->s_sb_time = &sbd->s_time;
	153	sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
	154	sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
	155	}
	156
8de52778	157	static void detected_v7(struct sysv_sb_info sbi, unsigned max_links)
1da177e4 LT	158	{
	159	struct buffer_head *bh2 = sbi->s_bh2;
	160	struct v7_super_block sbd = (struct v7_super_block )bh2->b_data;
	161
8de52778	162	*max_links = V7_LINK_MAX;
1da177e4 LT	163	sbi->s_fic_size = V7_NICINOD;
	164	sbi->s_flc_size = V7_NICFREE;
	165	sbi->s_sbd1 = (char *)sbd;
	166	sbi->s_sbd2 = (char *)sbd;
	167	sbi->s_sb_fic_count = &sbd->s_ninode;
	168	sbi->s_sb_fic_inodes = &sbd->s_inode[0];
	169	sbi->s_sb_total_free_inodes = &sbd->s_tinode;
	170	sbi->s_bcache_count = &sbd->s_nfree;
	171	sbi->s_bcache = &sbd->s_free[0];
	172	sbi->s_free_blocks = &sbd->s_tfree;
	173	sbi->s_sb_time = &sbd->s_time;
	174	sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize);
	175	sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
	176	}
	177
	178	static int detect_xenix(struct sysv_sb_info sbi, struct buffer_head bh)
	179	{
	180	struct xenix_super_block sbd = (struct xenix_super_block )bh->b_data;
	181	if ((__le32 )&sbd->s_magic == cpu_to_le32(0x2b5544))
	182	sbi->s_bytesex = BYTESEX_LE;
	183	else if ((__be32 )&sbd->s_magic == cpu_to_be32(0x2b5544))
	184	sbi->s_bytesex = BYTESEX_BE;
	185	else
	186	return 0;
	187	switch (fs32_to_cpu(sbi, sbd->s_type)) {
	188	case 1:
	189	sbi->s_type = FSTYPE_XENIX;
	190	return 1;
	191	case 2:
	192	sbi->s_type = FSTYPE_XENIX;
	193	return 2;
	194	default:
	195	return 0;
	196	}
	197	}
	198
	199	static int detect_sysv(struct sysv_sb_info sbi, struct buffer_head bh)
	200	{
	201	struct super_block *sb = sbi->s_sb;
	202	/* All relevant fields are at the same offsets in R2 and R4 */
	203	struct sysv4_super_block * sbd;
	204	u32 type;
	205
	206	sbd = (struct sysv4_super_block *) (bh->b_data + BLOCK_SIZE/2);
	207	if ((__le32 )&sbd->s_magic == cpu_to_le32(0xfd187e20))
	208	sbi->s_bytesex = BYTESEX_LE;
	209	else if ((__be32 )&sbd->s_magic == cpu_to_be32(0xfd187e20))
	210	sbi->s_bytesex = BYTESEX_BE;
	211	else
	212	return 0;
	213
	214	type = fs32_to_cpu(sbi, sbd->s_type);
	215
	216	if (fs16_to_cpu(sbi, sbd->s_nfree) == 0xffff) {
	217	sbi->s_type = FSTYPE_AFS;
	218	sbi->s_forced_ro = 1;
	219	if (!(sb->s_flags & MS_RDONLY)) {
	220	printk("SysV FS: SCO EAFS on %s detected, "
	221	"forcing read-only mode.\n",
	222	sb->s_id);
	223	}
	224	return type;
	225	}
	226
227	if (fs32_to_cpu(sbi, sbd->s_time) < JAN_1_1980) {
228	/* this is likely to happen on SystemV2 FS */
229	if (type > 3 \|\| type < 1)
230	return 0;
231	sbi->s_type = FSTYPE_SYSV2;
232	return type;
233	}
234	if ((type > 3 \|\| type < 1) && (type > 0x30 \|\| type < 0x10))
235	return 0;
236
237	/* On Interactive Unix (ISC) Version 4.0/3.x s_type field = 0x10,
238	0x20 or 0x30 indicates that symbolic links and the 14-character
239	filename limit is gone. Due to lack of information about this
240	feature read-only mode seems to be a reasonable approach... -KGB */
241
242	if (type >= 0x10) {
243	printk("SysV FS: can't handle long file names on %s, "
244	"forcing read-only mode.\n", sb->s_id);
245	sbi->s_forced_ro = 1;
246	}
247
248	sbi->s_type = FSTYPE_SYSV4;
249	return type >= 0x10 ? type >> 4 : type;
250	}
251
252	static int detect_coherent(struct sysv_sb_info sbi, struct buffer_head bh)
253	{
254	struct coh_super_block * sbd;
255
256	sbd = (struct coh_super_block *) (bh->b_data + BLOCK_SIZE/2);
257	if ((memcmp(sbd->s_fname,"noname",6) && memcmp(sbd->s_fname,"xxxxx ",6))
258	\|\| (memcmp(sbd->s_fpack,"nopack",6) && memcmp(sbd->s_fpack,"xxxxx\n",6)))
259	return 0;
260	sbi->s_bytesex = BYTESEX_PDP;
261	sbi->s_type = FSTYPE_COH;
262	return 1;
263	}
264
265	static int detect_sysv_odd(struct sysv_sb_info sbi, struct buffer_head bh)
266	{
267	int size = detect_sysv(sbi, bh);
268
269	return size>2 ? 0 : size;
270	}
271
272	static struct {
273	int block;
274	int (test)(struct sysv_sb_info , struct buffer_head *);
275	} flavours[] = {
276	{1, detect_xenix},
277	{0, detect_sysv},
278	{0, detect_coherent},
279	{9, detect_sysv_odd},
280	{15,detect_sysv_odd},
281	{18,detect_sysv},
282	};
283
284	static char *flavour_names[] = {
285	[FSTYPE_XENIX] = "Xenix",
286	[FSTYPE_SYSV4] = "SystemV",
287	[FSTYPE_SYSV2] = "SystemV Release 2",
288	[FSTYPE_COH] = "Coherent",
289	[FSTYPE_V7] = "V7",
290	[FSTYPE_AFS] = "AFS",
291	};
292
8de52778	293	static void (flavour_setup[])(struct sysv_sb_info , unsigned *) = {
1da177e4 LT	294	[FSTYPE_XENIX] = detected_xenix,
	295	[FSTYPE_SYSV4] = detected_sysv4,
	296	[FSTYPE_SYSV2] = detected_sysv2,
	297	[FSTYPE_COH] = detected_coherent,
	298	[FSTYPE_V7] = detected_v7,
	299	[FSTYPE_AFS] = detected_sysv4,
	300	};
	301
	302	static int complete_read_super(struct super_block *sb, int silent, int size)
	303	{
	304	struct sysv_sb_info *sbi = SYSV_SB(sb);
	305	struct inode *root_inode;
	306	char *found = flavour_names[sbi->s_type];
	307	u_char n_bits = size+8;
	308	int bsize = 1 << n_bits;
	309	int bsize_4 = bsize >> 2;
	310
	311	sbi->s_firstinodezone = 2;
	312
8de52778	313	flavour_setup[sbi->s_type](sbi, &sb->s_max_links);
1da177e4 LT	314
	315	sbi->s_truncate = 1;
	316	sbi->s_ndatazones = sbi->s_nzones - sbi->s_firstdatazone;
	317	sbi->s_inodes_per_block = bsize >> 6;
	318	sbi->s_inodes_per_block_1 = (bsize >> 6)-1;
	319	sbi->s_inodes_per_block_bits = n_bits-6;
	320	sbi->s_ind_per_block = bsize_4;
	321	sbi->s_ind_per_block_2 = bsize_4*bsize_4;
	322	sbi->s_toobig_block = 10 + bsize_4 * (1 + bsize_4 * (1 + bsize_4));
	323	sbi->s_ind_per_block_bits = n_bits-2;
	324
	325	sbi->s_ninodes = (sbi->s_firstdatazone - sbi->s_firstinodezone)
	326	<< sbi->s_inodes_per_block_bits;
	327
	328	if (!silent)
	329	printk("VFS: Found a %s FS (block size = %ld) on device %s\n",
	330	found, sb->s_blocksize, sb->s_id);
	331
	332	sb->s_magic = SYSV_MAGIC_BASE + sbi->s_type;
	333	/* set up enough so that it can read an inode */
	334	sb->s_op = &sysv_sops;
30304aba AV	335	if (sbi->s_forced_ro)
	336	sb->s_flags \|= MS_RDONLY;
	337	if (sbi->s_truncate)
	338	sb->s_d_op = &sysv_dentry_operations;
b8e1343f DH	339	root_inode = sysv_iget(sb, SYSV_ROOT_INO);
b8e1343f DH	340	if (IS_ERR(root_inode)) {
1da177e4 LT	341	printk("SysV FS: get root inode failed\n");
	342	return 0;
	343	}
48fde701	344	sb->s_root = d_make_root(root_inode);
1da177e4	345	if (!sb->s_root) {
1da177e4 LT	346	printk("SysV FS: get root dentry failed\n");
	347	return 0;
	348	}
1da177e4 LT	349	return 1;
	350	}
	351
	352	static int sysv_fill_super(struct super_block sb, void data, int silent)
	353	{
	354	struct buffer_head bh1, bh = NULL;
	355	struct sysv_sb_info *sbi;
	356	unsigned long blocknr;
	357	int size = 0, i;
	358
2ecd05ae AD	359	BUILD_BUG_ON(1024 != sizeof (struct xenix_super_block));
	360	BUILD_BUG_ON(512 != sizeof (struct sysv4_super_block));
	361	BUILD_BUG_ON(512 != sizeof (struct sysv2_super_block));
	362	BUILD_BUG_ON(500 != sizeof (struct coh_super_block));
	363	BUILD_BUG_ON(64 != sizeof (struct sysv_inode));
1da177e4	364
f8314dc6	365	sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
1da177e4 LT	366	if (!sbi)
1da177e4 LT	367	return -ENOMEM;
1da177e4 LT	368
	369	sbi->s_sb = sb;
	370	sbi->s_block_base = 0;
c07cb01c	371	mutex_init(&sbi->s_lock);
1da177e4	372	sb->s_fs_info = sbi;
e8c96f8c	373
1da177e4 LT	374	sb_set_blocksize(sb, BLOCK_SIZE);
1da177e4 LT	375
e8c96f8c	376	for (i = 0; i < ARRAY_SIZE(flavours) && !size; i++) {
1da177e4 LT	377	brelse(bh);
	378	bh = sb_bread(sb, flavours[i].block);
	379	if (!bh)
	380	continue;
	381	size = flavours[i].test(SYSV_SB(sb), bh);
	382	}
	383
	384	if (!size)
	385	goto Eunknown;
	386
	387	switch (size) {
	388	case 1:
	389	blocknr = bh->b_blocknr << 1;
	390	brelse(bh);
	391	sb_set_blocksize(sb, 512);
	392	bh1 = sb_bread(sb, blocknr);
	393	bh = sb_bread(sb, blocknr + 1);
	394	break;
	395	case 2:
	396	bh1 = bh;
	397	break;
	398	case 3:
	399	blocknr = bh->b_blocknr >> 1;
	400	brelse(bh);
	401	sb_set_blocksize(sb, 2048);
	402	bh1 = bh = sb_bread(sb, blocknr);
	403	break;
	404	default:
	405	goto Ebadsize;
	406	}
	407
	408	if (bh && bh1) {
	409	sbi->s_bh1 = bh1;
	410	sbi->s_bh2 = bh;
	411	if (complete_read_super(sb, silent, size))
	412	return 0;
	413	}
	414
	415	brelse(bh1);
	416	brelse(bh);
	417	sb_set_blocksize(sb, BLOCK_SIZE);
	418	printk("oldfs: cannot read superblock\n");
	419	failed:
	420	kfree(sbi);
	421	return -EINVAL;
	422
	423	Eunknown:
	424	brelse(bh);
	425	if (!silent)
	426	printk("VFS: unable to find oldfs superblock on device %s\n",
	427	sb->s_id);
	428	goto failed;
	429	Ebadsize:
	430	brelse(bh);
	431	if (!silent)
	432	printk("VFS: oldfs: unsupported block size (%dKb)\n",
	433	1<<(size-2));
	434	goto failed;
	435	}
	436
6d0b5456	437	static int v7_sanity_check(struct super_block sb, struct buffer_head bh)
1da177e4	438	{
1da177e4 LT	439	struct v7_super_block *v7sb;
1da177e4 LT	440	struct sysv_inode *v7i;
6d0b5456 LR	441	struct buffer_head *bh2;
	442	struct sysv_sb_info *sbi;
	443
	444	sbi = sb->s_fs_info;
	445
	446	/* plausibility check on superblock */
	447	v7sb = (struct v7_super_block *) bh->b_data;
	448	if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE \|\|
	449	fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD \|\|
	450	fs32_to_cpu(sbi, v7sb->s_fsize) > V7_MAXSIZE)
	451	return 0;
	452
	453	/* plausibility check on root inode: it is a directory,
	454	with a nonzero size that is a multiple of 16 */
	455	bh2 = sb_bread(sb, 2);
	456	if (bh2 == NULL)
	457	return 0;
	458
	459	v7i = (struct sysv_inode *)(bh2->b_data + 64);
	460	if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR \|\|
	461	(fs32_to_cpu(sbi, v7i->i_size) == 0) \|\|
	462	(fs32_to_cpu(sbi, v7i->i_size) & 017) \|\|
	463	(fs32_to_cpu(sbi, v7i->i_size) > V7_NFILES *
	464	sizeof(struct sysv_dir_entry))) {
	465	brelse(bh2);
	466	return 0;
	467	}
	468
	469	brelse(bh2);
	470	return 1;
	471	}
	472
	473	static int v7_fill_super(struct super_block sb, void data, int silent)
	474	{
	475	struct sysv_sb_info *sbi;
	476	struct buffer_head *bh;
1da177e4 LT	477
	478	if (440 != sizeof (struct v7_super_block))
	479	panic("V7 FS: bad super-block size");
	480	if (64 != sizeof (struct sysv_inode))
	481	panic("sysv fs: bad i-node size");
	482
f8314dc6	483	sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
1da177e4 LT	484	if (!sbi)
1da177e4 LT	485	return -ENOMEM;
1da177e4 LT	486
	487	sbi->s_sb = sb;
	488	sbi->s_block_base = 0;
	489	sbi->s_type = FSTYPE_V7;
49475555	490	mutex_init(&sbi->s_lock);
1da177e4 LT	491	sb->s_fs_info = sbi;
	492
	493	sb_set_blocksize(sb, 512);
	494
	495	if ((bh = sb_bread(sb, 1)) == NULL) {
	496	if (!silent)
	497	printk("VFS: unable to read V7 FS superblock on "
	498	"device %s.\n", sb->s_id);
	499	goto failed;
	500	}
	501
6d0b5456 LR	502	/* Try PDP-11 UNIX */
	503	sbi->s_bytesex = BYTESEX_PDP;
	504	if (v7_sanity_check(sb, bh))
	505	goto detected;
1da177e4	506
6d0b5456 LR	507	/* Try PC/IX, v7/x86 */
	508	sbi->s_bytesex = BYTESEX_LE;
	509	if (v7_sanity_check(sb, bh))
	510	goto detected;
1da177e4	511
6d0b5456 LR	512	goto failed;
	513
	514	detected:
1da177e4 LT	515	sbi->s_bh1 = bh;
	516	sbi->s_bh2 = bh;
	517	if (complete_read_super(sb, silent, 1))
	518	return 0;
	519
	520	failed:
6d0b5456 LR	521	printk(KERN_ERR "VFS: could not find a valid V7 on %s.\n",
6d0b5456 LR	522	sb->s_id);
1da177e4 LT	523	brelse(bh);
	524	kfree(sbi);
	525	return -EINVAL;
	526	}
	527
	528	/* Every kernel module contains stuff like this. */
	529
152a0836 AV	530	static struct dentry sysv_mount(struct file_system_type fs_type,
152a0836 AV	531	int flags, const char dev_name, void data)
1da177e4	532	{
152a0836	533	return mount_bdev(fs_type, flags, dev_name, data, sysv_fill_super);
1da177e4 LT	534	}
1da177e4 LT	535
152a0836 AV	536	static struct dentry v7_mount(struct file_system_type fs_type,
152a0836 AV	537	int flags, const char dev_name, void data)
1da177e4	538	{
152a0836	539	return mount_bdev(fs_type, flags, dev_name, data, v7_fill_super);
1da177e4 LT	540	}
	541
	542	static struct file_system_type sysv_fs_type = {
	543	.owner = THIS_MODULE,
	544	.name = "sysv",
152a0836	545	.mount = sysv_mount,
1da177e4 LT	546	.kill_sb = kill_block_super,
	547	.fs_flags = FS_REQUIRES_DEV,
	548	};
7f78e035	549	MODULE_ALIAS_FS("sysv");
1da177e4 LT	550
	551	static struct file_system_type v7_fs_type = {
	552	.owner = THIS_MODULE,
	553	.name = "v7",
152a0836	554	.mount = v7_mount,
1da177e4 LT	555	.kill_sb = kill_block_super,
	556	.fs_flags = FS_REQUIRES_DEV,
	557	};
7f78e035	558	MODULE_ALIAS_FS("v7");
fa7614dd	559	MODULE_ALIAS("v7");
1da177e4	560
1da177e4 LT	561	static int __init init_sysv_fs(void)
	562	{
	563	int error;
	564
	565	error = sysv_init_icache();
	566	if (error)
	567	goto out;
	568	error = register_filesystem(&sysv_fs_type);
	569	if (error)
	570	goto destroy_icache;
	571	error = register_filesystem(&v7_fs_type);
	572	if (error)
	573	goto unregister;
	574	return 0;
	575
	576	unregister:
	577	unregister_filesystem(&sysv_fs_type);
	578	destroy_icache:
	579	sysv_destroy_icache();
	580	out:
	581	return error;
	582	}
	583
	584	static void __exit exit_sysv_fs(void)
	585	{
	586	unregister_filesystem(&sysv_fs_type);
	587	unregister_filesystem(&v7_fs_type);
	588	sysv_destroy_icache();
	589	}
	590
	591	module_init(init_sysv_fs)
	592	module_exit(exit_sysv_fs)
	593	MODULE_LICENSE("GPL");