[PATCH] Clear task_struct->fs_excl on fork()

An oversight.  We don't want to carry the IO scheduler's "we hold exclusive fs
resources" hint over to the child across fork().

Acked-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>