vgextend Volume_Group_Name /dev/sdx0
lvextend --size +10G Volume_Group_Name/Logical_Volume_Name #provides extra 10 gigs out of new pool size. OR
lvextend --extents 90%FREE Volume_Group_Name/Logical_Volume_Name #makes the logical volume size 90% the size of the volume grolup
#(assuming filesystem is ext) and you did a fsck.
Note: sometimes you cannot assign all the extents as the logical volume has been set to using contiguous extents - you can turn this off although you lose file system performance from doing so. To turn it off.
lvchange -C n Volume_Group_Name/Logical_Volume_Name
#if you turn it off its unlikely you can set it back.