CentOS 7 – How to Remount as Read and Write

Yesterday my CentOS Linux 7 (Core) server experienced a hard disk problem. The HDD has since been replaced but the main partition is in read-only mode.

I'm trying to get the main partition usable again (making it read and write) but am having many issues.

mount as rw

I tried mount -n -o remount,rw / but this resulted in:

mount: / not mounted or bad option

       In some cases useful info is found in syslog - try
       dmesg | tail or so

dmesg | tail resulted in:

[  177.305240] Loading iSCSI transport class v2.0-870.
[  177.419722] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
[  177.446940] NFSD: starting 90-second grace period (net ffffffffa32fca00)
[  233.475427] systemd-readahead[2002]: Failed to open pack file: Read-only file system
[  267.629924] nfsd4: failed to purge old clients from recovery directory v4recovery
[  428.141830] EXT4-fs (md2): error count since last fsck: 1
[  428.141889] EXT4-fs (md2): initial error at time 1542775899: ext4_xattr_block_get:298: inode 6947097
[  428.142014] EXT4-fs (md2): last error at time 1542775899: ext4_xattr_block_get:298: inode 6947097
[  748.786866] EXT4-fs (md2): Couldn't remount RDWR because of unprocessed orphan inode list.  Please umount/remount instead
[  770.787648] EXT4-fs (md2): Couldn't remount RDWR because of unprocessed orphan inode list.  Please umount/remount instead

e2fsck

I tried repairing the orphaned inode list using:

e2fsck -f /dev/md2
e2fsck 1.42.9 (28-Dec-2013)
/dev/md2 has unsupported feature(s): metadata_csum
e2fsck: Get a newer version of e2fsck!

As the filesystem is in read-only mode I'm unable to download a newer version of e2fsck.

tune2fs

I tried tune2fs -O ^metadata_csum /dev/md2 and got:

tune2fs 1.42.9 (28-Dec-2013)
tune2fs: Filesystem has unsupported read-only feature(s) while trying to open /dev/md2
Couldn't find valid filesystem superblock.

How can I get this partition to be read and write again?

Thanks