commit 7c3d3f2a87b01ff167a5f048285d5e3dee920235
author Joe Thornber <ejt@redhat.com> Fri May 10 14:37:20 2013 +0100
committer Alasdair G Kergon <agk@redhat.com> Fri May 10 14:37:20 2013 +0100
tree 44b483cd78221e412b314c872cb5ddedfdfd2abe
parent 24347e9595704464f62a4ed8f46abf62b4c79cdd

dm persistent data: add threshold callback to space map

Add a threshold callback function to the persistent data space map
interface for a subsequent patch to use.

dm-thin and dm-cache are interested in knowing when they're getting
low on metadata or data blocks.  This patch introduces a new method
for registering a callback against a threshold.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>