We need to make sure we don't reuse the data blocks released
during the transaction untill the transaction commits. We force
this mode only for ordered and journalled mode. Writeback mode
already don't provided data consistency.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>