XFS corrupt after RAID failure and resync

[David Raffelt]

Hi All,

I have 7 drives in a RAID6 configuration with a XFS partition (running Arch
linux). Recently two drives dropped out simultaneously, and a hot spare
immediately synced successfully so that I now have 6/7 drives up in the
array.

After a reboot (to replace the faulty drives) the XFS file system would not
mount. Note that I had to perform a hard reboot since the server hung on
shutdown. When I try to mount I get the following error:
mount: mount /dev/md0 on /export/data failed: Structure needs cleaning

I have tried to perform: xfs_repair /dev/md0
And I get the following output:

Phase 1 - find and verify superblock...
couldn't verify primary superblock - bad magic number !!!
attempting to find secondary superblock...
..............................................................................
..............................................................................
                          [many lines like this]
..............................................................................
..............................................................................
found candidate secondary superblock...unable to verify superblock,
continuing
...
...........................................................................

Note that it has been scanning for many hours and has located several
secondary superblocks with the same error. It is till scanning however
based on other posts I'm guessing it will not be successful.

To investigate the superblock info I used xfs_db and the magic number looks
ok:
sudo xfs_db /dev/md0
xfs_db> sb
xfs_db> p

magicnum = 0x58465342
blocksize = 4096
dblocks = 3662666880
rblocks = 0
rextents = 0
uuid = e74e5814-3e0f-4cd1-9a68-65d9df8a373f
logstart = 2147483655
rootino = 1024
rbmino = 1025
rsumino = 1026
rextsize = 1
agblocks = 114458368
agcount = 32
rbmblocks = 0
logblocks = 521728
versionnum = 0xbdb4
sectsize = 4096
inodesize = 512
inopblock = 8
fname = "\000\000\000\000\000\000\000\000\000\000\000\000"
blocklog = 12
sectlog = 12
inodelog = 9
inopblog = 3
agblklog = 27
rextslog = 0
inprogress = 0
imax_pct = 5
icount = 4629568
ifree = 34177
fdblocks = 362013500
frextents = 0
uquotino = 0
gquotino = null
qflags = 0
flags = 0
shared_vn = 0
inoalignmt = 2
unit = 128
width = 640
dirblklog = 0
logsectlog = 12
logsectsize = 4096
logsunit = 4096
features2 = 0xa
bad_features2 = 0xa
features_compat = 0
features_ro_compat = 0
features_incompat = 0
features_log_incompat = 0
crc = 0 (unchecked)
pquotino = 0
lsn = 0


Any help or suggestions at this point would be much appreciated!  Is my
only option to try a repair -L?

Thanks in advance,
Dave
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