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]
[AV: parser.h inclusion was a rudiment of discarded stuff]
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: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/sysv/super.c b/fs/sysv/super.c
index 5c0aab0..a0b0cda 100644
--- a/fs/sysv/super.c
+++ b/fs/sysv/super.c
@@ -434,12 +434,46 @@
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 +487,6 @@
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 +498,27 @@
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;