Commit ab654bab authored by Lubomir Rintel's avatar Lubomir Rintel Committed by Linus Torvalds
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fs/sysv/super.c: add support for non-PDP11 v7 filesystems 



This adds byte order autodetection (of PDP-11 and LE filesystems).  No
attempt is made to detect big-endian filesystems -- were there any?
Tested with PDP-11 v7 filesystems and PC-IX maintenance floppy.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarLubomir Rintel <lkundrak@v3.sk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0bcaa65a

fs/sysv/super.c

+51 −24
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/init.h>

#include <linux/slab.h>

#include <linux/buffer_head.h>

#include <linux/parser.h>

#include "sysv.h"



/*
@@ -434,12 +435,46 @@ Ebadsize: 
	goto failed;

}



static int v7_fill_super(struct super_block *sb, void *data, int silent)

static int v7_sanity_check(struct super_block *sb, struct buffer_head *bh)

{

	struct sysv_sb_info *sbi;

	struct buffer_head *bh, *bh2 = NULL;

	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");
@@ -453,7 +488,6 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent) 
	sbi->s_sb = sb;

	sbi->s_block_base = 0;

	sbi->s_type = FSTYPE_V7;

	sbi->s_bytesex = BYTESEX_PDP;

	sb->s_fs_info = sbi;

	

	sb_set_blocksize(sb, 512);
@@ -465,34 +499,27 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent) 
		goto failed;

	}



	/* 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)

		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;



	/* 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(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)))

	goto failed;

	brelse(bh2);

	bh2 = NULL;



detected:

	sbi->s_bh1 = bh;

	sbi->s_bh2 = bh;

	if (complete_read_super(sb, silent, 1))

		return 0;



failed:

	brelse(bh2);

	printk(KERN_ERR "VFS: could not find a valid V7 on %s.\n",

		sb->s_id);

	brelse(bh);

	kfree(sbi);

	return -EINVAL;

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