his change, the extent merge
after converting an unwritten extent to initialized extent takes the wrong
extent and cause data corruption.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
wŠ^¬’Cx