XFS over LVM

[Suresh Grandhi <Sureshg@xxxxxxx>]

        Hi.
                I am using XFS over LVM device. The LV is formatted with XFS
file system.
        I have reduced the size of the LV device with "lvreduce" by 1G size.
After that 
        i could not able to mount the device. Also I ran xfs_repair over
that device and still
        not able to do. After expanding the LV device to the same size as
original, i could able to 
        mount the device. 

        Is there a way to make the filesystem know about the change in the 
        size of the LV device? 

        Is there  a way to make the device and filesystem change
dynamically??

        Your help is appreciated.

        regards,
        suresh