Oracle Linux -- boot problem, panic, mount: you must specify the filesystem type, fsck, Logical Volume, HP server

After replacing a failed disk drive, which was a member of a Raid 6 configuration, root filesystem became read-only and when we rebooted the Server, OS couldnt boot itself. (note that, OS was Oracle Linux 6.5 64 bit)

It was obvious that , the mount command which was a part of the boot sequence was failing, and it was the root filesystem what the mount command was failing for.

There were no fsck errors or fsck warning during the boot(it was the root filesystem, so maybe OS couldnt even warn us) , but we have decided make a check using Oracle Linux cd.

So, we have first burned a Oracle Linux DVD and used the external DVD drive for booting it.
It was failing. It actually didn't fail , but displayed the following warning and dropped us to syslinux boot prompt. It was complaining about "No DEFAULT or UI configuration directive found".
When we saw the error, we thought that, there could be problem with Oracle Linux boot sequence and the external  DVD drive. So we have created a bootable Oracle Linux USB and booted Oracle Linux from there.
We were right, Oracle Linux could boot itself using the usb drive

So, what we did to solve the error was;

• run the rescue mode and made us drop ourselves in a shell
• activated all the Logical Volume groups (vgchange -a y)
• checked mount command with the root lvm and saw it was failing as the same way boot sequence was failing. (mount /dev/Volumegroup_name/LVM_name /foobar
• use blkid to find the filesystem of the root lvm (blkid /dev/Volumegroup_name/LVM_name 
• use fsck.filesystem(in our case it was ext4 -> fsck.ext4 -y) to repair the filesystem.
• and lastly reboot.