CentOS - Oct 2015 - USB drive is "read-only file system" and cannot umount - how to fix

I 'just' noticed that at some point, my USB backup drive on my server is
mounted as read-only and all of my background sync cron jobs have been 
failing.

So I need to fix this without rebooting the server.

I can VNC into the server and running "mount" shows:

/dev/sdc1 on /media/HD103SI type ext4 (rw,nosuid,nodev,uhelper=udisks)

and umount gets:

# umount /dev/sdc1
umount: /media/HD103SI: device is busy.
         (In some cases useful info about processes that use
          the device is found by lsof(8) or fuser(1))

How can I get this drive r/w?

I 'just' noticed that at some point, my USB backup drive on my
server
>is 
>mounted as read-only and all of my background sync cron jobs have been 
>failing.
>
>So I need to fix this without rebooting the server.
>How can I get this drive r/w?
Have you tried "mount -o remount,rw <mountpoint>"?

The unanswered question here is why did it go read only, and does this condition
still exist?

Barry

On 10/25/2015 11:12 AM, Barry Brimer wrote:
> I 'just' noticed that at some point, my USB backup drive on my
server
>> is
>> mounted as read-only and all of my background sync cron jobs have been
>> failing.
>>
>> So I need to fix this without rebooting the server.
>> How can I get this drive r/w?
> Have you tried "mount -o remount,rw <mountpoint>"?
# mount -o remount,rw /media/HD103SI/
mount: cannot remount block device /dev/sdc1 read-write, is write-protected

> The unanswered question here is why did it go read only, and does this
condition still exist?
The burning question of the day......

Should I 'just' unplug it, power cycle it and reconnect it?