Ubuntu :: Unable To Mount XFS After Electricity Failure

I'm using Ubuntu 10.10 x86_64, with 2T HDD x5 grouped as RAID5 using RAID controller (dell perc 6/i), result in a 8TB disk, and I put it to a single partition in XFS. Just now one light bulb went wrong and caused whole house power fail, sadly during that time I'm copying some data to that partition. After I clear the power issue and turn on the computer, the partition still can mount, so I continue copying, and that gives me some IO error. I assume it is some kind of problem that need a file system check, so I unmount it, and run xfs_repair.

However xfs_repair shows the partition has not been unmount so I restarted the computer. After restarting, during the loading screen the system prompt me that it cannot find the file system, and I pressed 'S' to skip (btw 'M' for manually maintenance, but I didn't try) Then there comes the problem: the partition cannot be mounted anymore. I tried using palimpsest (the disk utility) to check, the partition shows normally (i.e., there's a 8T disk with a single partition in XFS), but when I try to mount it, the first time I click 'mount' results in nothing, repeat click will get an error 'The device is busy: A job is pending on /dev/sdb1'.

Checking the process running I found this:
process 'mount', status 'uninterruptible', command line 'mount /dev/sdb1', waiting channel 'call_rwsem_down_write_failed'.
Also other operations with that partition does not work, such as xfs_repair or mount, will just halt (and the waiting channel is 'get_sb_bdev')