ufs: permit mounting of BorderWare filesystems

I recently had to recover some files from an old broken machine that was
running BorderWare Document Gateway.  It's basically a drop in web server
for sharing files.  From the look of the init process and using strings on
of a few files it seems to be based on FreeBSD 3.3.

The process turned out to be more difficult than I imagined, but to cut a
long story short BorderWare in their wisdom use a nonstandard magic number
in their UFS (ufstype=44bsd) file systems.  Thus Linux refuses to mount
the file systems in order to recover the data.  After a bit of hunting I
was able to make a quick fix to fs/ufs/super.c in order to detect the new
magic number.

I assume that this number is the same for all installations.  It's quite
easy to find out from ufs_fs.h.  The superblock sits 8k into the block
device and the magic number its 1372 bytes into the superblock struct.

# dd if=/dev/sda5 skip=$(( 8192 + 1372 )) bs=1 count=4 2> /dev/null | hd
00000000  97 26 24 0f                                       |.&$.|
#

Signed-off-by: Thomas Stewart <thomas@stewarts.org.uk>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index 14743d935a93..ad9bc1ebd3a6 100644
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -918,6 +918,7 @@ again:
         sbi->s_bytesex = BYTESEX_LE;
         switch ((uspi->fs_magic = fs32_to_cpu(sb, usb3->fs_magic))) {
                 case UFS_MAGIC:
+                case UFS_MAGIC_BW:
                 case UFS2_MAGIC:
                 case UFS_MAGIC_LFN:
                 case UFS_MAGIC_FEA:
@@ -927,6 +928,7 @@ again:
         sbi->s_bytesex = BYTESEX_BE;
         switch ((uspi->fs_magic = fs32_to_cpu(sb, usb3->fs_magic))) {
                 case UFS_MAGIC:
+                case UFS_MAGIC_BW:
                 case UFS2_MAGIC:
                 case UFS_MAGIC_LFN:
                 case UFS_MAGIC_FEA: