From: Joe Thornber Date: Wed, 28 Mar 2012 17:41:28 +0000 (+0100) Subject: dm thin: support read only external snapshot origins X-Git-Tag: v3.4-rc1~68^2~6 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2dd9c257fbc243aa76ee6db0bb8371f9f74fad2d;p=pandora-kernel.git dm thin: support read only external snapshot origins Support the use of an external _read only_ device as an origin for a thin device. Any read to an unprovisioned area of the thin device will be passed through to the origin. Writes trigger allocation of new blocks as usual. One possible use case for this would be VM hosts that want to run guests on thinly-provisioned volumes but have the base image on another device (possibly shared between many VMs). Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon --- Reading git-diff-tree failed