Re: raid5: I lost a XFS file system due to a minor IDE cable problem

[Pallai Roland <dap@mail.index.hu>]

On Friday 25 May 2007 02:05:47 David Chinner wrote:
> "-o ro,norecovery" will allow you to mount the filesystem and get any
> uncorrupted data off it.
>
> You still may get shutdowns if you trip across corrupted metadata in
> the filesystem, though.
This filesystem is completely dead.

hq:~# mount -o ro,norecovery /dev/loop1 /mnt/r5
May 28 13:41:50 hq kernel: Mounting filesystem "loop1" in no-recovery mode.  
Filesystem will be inconsistent.
May 28 13:41:50 hq kernel: XFS: failed to read root inode

hq:~# xfs_db /dev/loop1
xfs_db: cannot read root inode (22)
xfs_db: cannot read realtime bitmap inode (22)
Segmentation fault

hq:~# strace xfs_db /dev/loop1
_llseek(4, 0, [0], SEEK_SET)            = 0
read(4, "XFSB\0\0\20\0\0\0\0\0\6\374\253\0\0\0\0\0\0\0\0\0\0\0\0"..., 512) = 
512
pread(4, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 512, 
480141901312) = 512
pread(4, "\30G$L\203\33OE \256=\207@\340\264O\"\324\2074DY\323\6"..., 8192, 
131072) = 8192
write(2, "xfs_db: cannot read root inode ("..., 36xfs_db: cannot read root 
inode (22)
) = 36
pread(4, "\30G$L\203\33OE \256=\207@\340\264O\"\324\2074DY\323\6"..., 8192, 
131072) = 8192
write(2, "xfs_db: cannot read realtime bit"..., 47xfs_db: cannot read realtime 
bitmap inode (22)
) = 47
--- SIGSEGV (Segmentation fault) @ 0 (0) ---
+++ killed by SIGSEGV +++


Browsing with hexdump -C, seems like a part of a PDF file is at 128Kb, on the 
place of the root inode. :(


--
 d