dm thin: add 'no_space_timeout' dm-thin-pool module param

dm thin: add 'no_space_timeout' dm-thin-pool module param

commit 80c578930ce77ba8bcfb226a184b482020bdda7b upstream.

Commit 85ad643b ("dm thin: add timeout to stop out-of-data-space mode
holding IO forever") introduced a fixed 60 second timeout.  Users may
want to either disable or modify this timeout.

Allow the out-of-data-space timeout to be configured using the
'no_space_timeout' dm-thin-pool module param.  Setting it to 0 will
disable the timeout, resulting in IO being queued until more data space
is added to the thin-pool.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>