When we convert an uninitialized extent to an initialized extent
we need to make sure we return the number of blocks in the
extent from the file system block corresponding to logical
file block.  Otherwise we cache wrong extent details and this
results in file system corruption.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>