Compromised ext4 filesystem after mdadm manipulation error

["L.M.J" <linuxmasterjedi@free.fr>]

Hi,

  For the third time, I had to change a failed drive from my home linux 
RAID5
  box. Previous one went right and this time, I don't know what I did 
wrong,
  but I broke my RAID5. Well, at least, he didn't want to start.
  /dev/sdb was the failed drive
  /dev/sdc and /dev/sdd are OK.

  I tried to reassemble the RAID with this command after I replace sdb 
and
  create a new partition :
  ~# mdadm -Cv /dev/md0 --assume-clean --level=5 --raid-devices=3 
/dev/sdc1 /dev/sdd1 /dev/sdb1

  -> -C was not a good idea here

  Well, I guess I did an another mistake here, I should have done this 
instead :
  ~# mdadm -Av /dev/md0 --assume-clean --level=5 --raid-devices=3 
/dev/sdc1 /dev/sdd1 missing


  Maybe this wipe out my data...

  Let's go futher, then, pvdisplay, pvscan, vgdisplay returns empty
  information :-(

  Google helped me, and I did this :
  ~# dd if=/dev/md0 bs=512 count=255 skip=1 of=/tmp/md0.txt

	[..]
	physical_volumes {
		pv0 {
			id = "5DZit9-6o5V-a1vu-1D1q-fnc0-syEj-kVwAnW"
			device = "/dev/md0"
			status = ["ALLOCATABLE"]
			flags = []
			dev_size = 7814047360
			pe_start = 384
			pe_count = 953863
		}
	}
	logical_volumes {

		lvdata {
			id = "JiwAjc-qkvI-58Ru-RO8n-r63Z-ll3E-SJazO7"
			status = ["READ", "WRITE", "VISIBLE"]
			flags = []
			segment_count = 1
	[..]



  Since I saw lvm information, I guess I haven't lost all information 
yet...

  I tried an unhoped command :
  ~# pvcreate --uuid "5DZit9-6o5V-a1vu-1D1q-fnc0-syEj-kVwAnW" 
--restorefile /etc/lvm/archive/lvm-raid_00302.vg /dev/md0

  Then,
  ~# vgcfgrestore lvm-raid

  ~# lvs -a -o +devices
  LV     VG       Attr   LSize   Origin Snap%  Move Log Copy%  Convert  
Devices
  lvdata lvm-raid -wi-a- 450,00g                                       
/dev/md0(148480)
  lvmp   lvm-raid -wi-a-  80,00g                                       
/dev/md0(263680)

  Then :
  ~# lvchange -ay /dev/lvm-raid/lv*

  I was quite happy until now.
  Problem appears now when I try to mount those 2 LV (lvdata & lvmp) as 
ext4 partition :
  ~# mount /home/foo/RAID_mp/

  ~# mount | grep -i mp
     /dev/mapper/lvm--raid-lvmp on /home/foo/RAID_mp type ext4 (rw)

  ~# df -h /home/foo/RAID_mp
     Filesystem                  Size  Used Avail Use% Mounted on
     /dev/mapper/lvm--raid-lvmp   79G   61G   19G  77% 
/home/foo/RAID_mp


  Here is the big problem
  ~# ls -la /home/foo/RAID_mp
     total 0

  I did a LVM R/W snapshot on the /dev/mapper/lvm--raid-lvmp LV, I fsck 
it. I recover 50% of the files only, all located in lost-+found/ 
directory with names heading with #xxxxx.

  I would like to know if there is a last chance to recover ma data ?

  Thanks