A quick search using the error message in your question was not particularly helpful, but a couple of things come to mind:
Here are some things to try. If none of them resolve the issue, I would suggest you try replacing your SD card.
I guess you will have tried this by now, but just in case...
/tmp has permissions
$ ls -ld /tmp
drwxrwxrwt 9 root root 4096 Aug 30 06:18 tmp
If they are different than this, set them correctly:
$ sudo chmod a+rwxt /tmp
3. check your
/etc/fstab & verify
/ is properly mounted
$ cat /etc/fstab
The 2nd or third line should look like this (excepting the
PARTUUID=6c586e13-02 / ext4 defaults,noatime 0 1
fsck on your unmounted file system:
fsck should be run only on an unmounted file system. If you have another RPi or Linux system, you can remove your SD card, plug it into this other system, and run
fsck on it.
If you don't have another system - or simply want to do the enire process on your RPi - you can try this procedure to run
fsck on your RPi.
5. replace µSD card
Again, if none of these steps has resolved your issue, you may find that replacing your µSD card is required. If you wish to back up your system before trying this, I'd suggest using the image-utils package for this.