Cherry pick security-related fix 592acbf16821288ecdc4192c47e3774a4c48bb64 ("ext4: zero out the unused memory region in the extent tree block") to 3.18.y and 4.4.y
The cherry-pick is clean and requires no back-porting. Is already present in 4.9.y+
Signed-off-by: Mark Salyzynsalyzyn@android.com
To: stable stable@vger.kernel.org # 3.18.y 4.4.y
Cc: LKML linux-kernel@vger.kernel.org