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fs/sysv/super.c: add support for non-PDP11 v7 filesystems

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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: Lubomir Rintel <lkundrak@v3.sk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Lubomir Rintel 2010-08-10 18:03:34 -07:00 committed by Linus Torvalds
parent 0bcaa65a56
commit ab654bab04
1 changed files with 51 additions and 24 deletions
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75
fs/sysv/super.c
View file

@ -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 @@ static int sysv_fill_super(struct super_block *sb, void *data, int silent)
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, *bh2 = NULL;
struct v7_super_block *v7sb;
struct sysv_inode *v7i;
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;
/* 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;
/* 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:
brelse(bh2);
printk(KERN_ERR "VFS: could not find a valid V7 on %s.\n",
sb->s_id);
brelse(bh);
kfree(sbi);
return -EINVAL;