EXT4 file system always mounted in ReadOnly: writeback?

Hi all,
I'm running OpenMediaVault(OMV) and I've upgraded from Debian 7 to Debian 8, with upgrade of OMV 2 to 3.
After the upgrade, my ext4 filesystem is systematically mounted in ReadOnly mode.
I did fsck on /dev/sda1; it is clean (anyway it was running perfectly before). FYI, it is a SSD.
In the journal I found out that the file system is mounted with writeback data mode, while it is not specified in fstab. Googling that, it seems that having writeback mode on filesystem forces it in read only mode. Do you confirm?
After hours of investigations, I'm still stuck, but here are some information I collected:
- in previous fstab (on debian 7/OMV 2), data=writeback was specified
- on my new install (debian 8/OMV 3), even by forcing data=ordered in fstab for my fs, / is still mounted in writeback mode. I did not succeed to force ordered mode I guess there is something in the disk stating it was writeback before, and it cannot switch back ??

Your feedbacks will be appreciated; I'm running omv for my backups and actually need it

I've just succeeded to force the mount of file system using ordered data mode with Tune2fs, but it is still mounted in read only mode.
The root cause of my issue is not the writeback mode of the fs.
Now I'm completely stuck...

that's also my concern: dmesg does not show any error when mounting the disk.
I forgot to mention in my initial post: SmartCtl long test is PASS. There is no error on my disk.

Godness... I've fixed this issue and I can't believe it can happen :oops: :twisted:
The root cause was that I had space instead of tab wetween characters in my /etc/fstab for my exports :oops:
What is unbelievable is that:
1/ this fstab did work fine on debian 7,
2/ export was not binded and generate errors with nfsd, which causes finally my filesystem mounted in read only !! :twisted:

I guess there is something to investigate here on OS side, as this is tricky to analyse (no debug info as file system is read only) and many people will waste time on that.

Regards