Only send SIGXFSZ when exceeding rlimits.

Only send SIGXFSZ when exceeding rlimits.

Some users have been having problems with utilities like cp or dd dumping
core when they try to copy a file that's too large for the destination
filesystem (typically, > 4gb).  Apparently, some defunct standards required
SIGXFSZ to be sent in such circumstances, but SUS only requires/allows it
for when a written file exceeds the process's resource limits.  I'd like to
limit SIGXFSZs to the bare minimum required by SUS.

Patch sent per http://lkml.org/lkml/2007/4/10/302

Signed-off-by: Micah Cowan <micahcowan@ubuntu.com>
Acked-by: Alan Cox <alan@redhat.com>
Cc: <reiserfs-dev@namesys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>