ext4: Fix quota accounting error with fallocate

ext4: Fix quota accounting error with fallocate

commit 5f634d064c709ea02c3cdaa850a08323a4a4bf28 upstream (as of v2.6.33-rc6)

When we fallocate a region of the file which we had recently written,
and which is still in the page cache marked as delayed allocated blocks
we need to make sure we don't do the quota update on writepage path.
This is because the needed quota updated would have already be done
by fallocate.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>