fs: Fix theoretical division by 0 in super_cache_scan().
fs: Fix theoretical division by 0 in super_cache_scan().

total_objects could be 0 and is used as a denom.

While total_objects is a "long", total_objects == 0 unlikely happens for
3.12 and later kernels because 32-bit architectures would not be able to
hold (1 << 32) objects. However, total_objects == 0 may happen for kernels
between 3.1 and 3.11 because total_objects in prune_super() was an "int"
and (e.g.) x86_64 architecture might be able to hold (1 << 32) objects.

Signed-off-by: Tetsuo Handa <3d00b54ad717112934d0b63b7ac2975b44022a61@I-love.SAKURA.ne.jp>
Reviewed-by: Christoph Hellwig <923f7720577207a44b32e59bbfbea59d27f1ae8e@lst.de>
Cc: stable <4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@kernel.org> # 3.1+
Signed-off-by: Al Viro <de609eb4d5d70b1d38ec6642adbfc33a2781f63c@zeniv.linux.org.uk>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs