When attempting to mount a non-directory which exists, return ENOTDIR instead
of ENOENT. If stat() or statfs() failed, don't pass part of the invalid
(struct statfs) to ex_search(). In that same case, preserve the value of "bad"
rather than overwriting with EACCES.
Submitted by: Bruce Leverett (Panasas)
Reviewed by: rmacklem
MFC after: 1 week
Sponsored by: Panasas
Differential Revision: https://reviews.freebsd.org/D14438
b235f015f8