Cannot write to SD card

[Andy Green]

Somebody in the thread at some point said:
> I have a 2 GB Sandisk SD card that I often write to. Just today, it
> has started to be mounted read-only:
> cp: cannot create regular file `bg.jpg2': Read-only file system

Have a look in

dmesg

to see if the ro filesystem is the reaction to IO errors.

> So I tried unmounting it, but the device seems to be busy:
> [root at localhost ~]# umount /media/disk
> umount: /media/disk: device is busy
> umount: /media/disk: device is busy

lsof -n | grep media/disk

should give a clue about the process that holds an open handle to
something on the device.

-Andy