Recovering XFS Partition of Type FAT16

[Dave Chinner]

On Mon, Jul 04, 2011 at 10:23:55AM +0000, Volkan YAZICI wrote:
> Hi,
> 
> I have an XFS partition, which is
> 
> 1) Mistakenly quick formatted as FAT16.
> 2) At first, I couldn't see in "fdisk -l" that it is set to FAT16,
> instead of Linux. Hence, tried to fix it with xfs_recover. xfs_recover
> returned 0, and mount operation succeeded; but mounted fs size
> appeared as 20GB (despite it is 350GB) and almost every file was
> missing.
> 3) Later, I set the type of /dev/sda1 (the only partition in /dev/sda)
> to Linux, re-run xfs_recover, but nothing changed: Same fs size (20GB)
> and same missing files.

What is this xfs_recover tool you speak of? I've never heard of it,
I can't find any direct links to it in google (only forum posts from
years ago about how great it is) so I have no idea what you've done to
your filesystem...

> I open the system with Knoppix, and below are the partition
> diagnostics. I need urgent help to recover the files. I will be
> really, really appreciated for any help! (If you need further
> information, just drop me a mail.)
> 
> 
> Best.
> 
> 
> # fdisk -l
> 
> Disk /dev/sda: 320.1 GB, 320072933376 bytes
> 255 heads, 63 sectors/track, 38913 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x447c435f
> 
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sda1   *           1       38913   312568641   83  Linux
> 
> 
> # mount | grep /dev/sda1
> /dev/sda1 on /media/sda1 type xfs (rw,relatime,attr2,noquota)
> 
> 
> # df -h | grep /dev/sda1
> /dev/sda1              19G  4,2G   15G  23% /media/sda1
> 
> # xfs_info /mnt/sda1
> meta-data=/dev/sda1              isize=256    agcount=4, agsize=1226963 blks
>          =                       sectsz=512   attr=2
> data     =                       bsize=4096   blocks=4907849, imaxpct=25
>          =                       sunit=0      swidth=0 blks
> naming   =version 2              bsize=4096   ascii-ci=0
> log      =internal               bsize=4096   blocks=2560, version=2
>          =                       sectsz=512   sunit=0 blks, lazy-count=1
> realtime =none                   extsz=4096   blocks=0, rtextents=0

That looks like a newly made 20GB XFS filesystem, not the result of
repairing a 350GB filesystem...

If I were you, I'd be restoring from backups. You do have backups,
right?

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com