I'm not a total linux newbie, but I figure this is a newbie mistake, so here it is.

I'm running fedora 21 xfce on a triple boot system (using grub to select the os), so if it's at all possible to avoid a reinstall that would be very awesome.
What happened:
I ran out of space on my root partition (lvm). Tried to figure out how to resize the root partition while tired, gave up, decided to move /usr to my home partition and create a symlink. Copied /usr to /home/usr, deleted /usr. Unable to create the symlink now (duh! as I said, I was tired), booted into liveusb disk to create the symlink. Couldn't boot after that and gave up for the night. This morning I was clear enough to figure out resizing the partitions, so I did and then copied /home/usr back to /usr. Rebooted and everything seems normal until I want to login. Logging in just dumps me back at the login screen, wether I use root, user runlevel 5 or runlevel 3, no matter. In runlevel 3 there might be an error message but it flashes by so quickly I can't read it. Authentication does proceed, because logging in with a wrong username or password gives the proper error.
Google has not provided me with any useful hints, so I'm at a loss. Can someone please help me out?

Many thanks,

Willem

Can you login on console (press ctrl-alt-f1)? Can you login as root on console (does fedora have the root login option?)

Not sure about xfce but you may have messages in $HOME/.xsession-errors

If all your files are intact it sounds a bit like permission issues to me. Check if home directories are writable/readable by the corresponding users.

selinux checks the permissions and se context on the /home and /usr ( "/usr" SHOULD be in / and not separate ) partitions
and if NOT correct PROTECTS!!! the system by killing the boot or login

it is ?? iffy ?? maybe ?? possible to use yum and rpm to fix it

but that will take a week . I do mean maybe 5 to 7 days to manually find everything

reinstall , this will take 30 min.

Hello John VV,

thanks for your reply. I understand that this is happening and that the os does this for protection. However, I'm not *missing* any files. I simply moved /usr to another partition and then moved it back again. So I'm thinking this should repairable, probably a permissions thing, like otoomet mentioned?

Willem

So I ended up reinstalling. Took a bit longer than 30 mins though, but as always, the system is much nicer now.

Thanks for thinking along!