I have the problem that my machine turned the root filesystem into readonly mode and remounting it as writeable won't work:
# mount -o remount,rw /dev/sda1 /
mount: block device /dev/sda1 is write-protected, mounting read-only
I want to copy some data away from that system and I attached a USB drive and tried to mount it:
# mount -t ext3 /dev/sdb1 /mnt
mount: /dev/sdb1 already mounted or /mnt busy
/mnt is an empty directory, so mounting there should usually work, but it seems that having this directory on a readonly filesystem doesn't make it possible to mount something there.
I think there is no activity going on for /mnt, since the following command doesn't return any output:
# lsof | grep "/mnt" | grep -v grep
There is no other partition mounted as the readonly root filesystem at the moment. Is it possible to still get the attached disk into the directory hierarchy somehow?