reboot your system to an rescue mode and skip to chroot mode
then do
#lvm pvscan
#lvm vgscan
#lvm lvscan
#e2fsck -f /dev/[volgroupname]/[lvname]
#resize2fs /dev/[volgroupname]/[lvname] [volume spcace]
#lvm lvreduce -L [volume spcace] /dev/[volgroupname]/[lvname]