ext4: avoid a potential overflow in ext4_es_can_be_merged()
ext4: avoid a potential overflow in ext4_es_can_be_merged()

Check the length of an extent to avoid a potential overflow in
ext4_es_can_be_merged().

Signed-off-by: Zheng Liu <927570c33013ae711b16b2f69d88304bb3fcc969@taobao.com>
Signed-off-by: "Theodore Ts'o" <4ed386e0495d3e109932df055831d9ec2f824927@mit.edu>
Cc: Dmitry Monakhov <eecfa5af1016ca9db755569d9919e212ab6a1c94@openvz.org>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas