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

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>
Cc: stable@vger.kernel.org # 3.14+

1 files changed, 4 insertions, 1 deletions

diff --git a/Documentation/device-mapper/thin-provisioning.txt b/Documentation/device-mapper/thin-provisioning.txt
index 05a27e9442bd..2f5173500bd9 100644
--- a/Documentation/device-mapper/thin-provisioning.txt
+++ b/Documentation/device-mapper/thin-provisioning.txt
@@ -309,7 +309,10 @@ ii) Status
     error_if_no_space|queue_if_no_space
         If the pool runs out of data or metadata space, the pool will
         either queue or error the IO destined to the data device.  The
-        default is to queue the IO until more space is added.
+        default is to queue the IO until more space is added or the
+        'no_space_timeout' expires.  The 'no_space_timeout' dm-thin-pool
+        module parameter can be used to change this timeout -- it
+        defaults to 60 seconds but may be disabled using a value of 0.
 
 iii) Messages