Problem identified by Jan Kasprzak.

Limit on domainname_max (currently 50) is too small.

Just use the beginning of input buffer as scratch space for it, and save a
little stack space while we're at it.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>