dm cache: policy ignore hints if generated by different version
authorMike Snitzer <snitzer@redhat.com>
Wed, 20 Mar 2013 17:21:28 +0000 (17:21 +0000)
committerAlasdair G Kergon <agk@redhat.com>
Wed, 20 Mar 2013 17:21:28 +0000 (17:21 +0000)
commitea2dd8c1ed0becee9812cf0840a9cd553ed398fe
tree938398729161784ad0157dc94edaed1f9e9792a3
parent4e7f506f6429636115e2f58f9f97089acc62524a
dm cache: policy ignore hints if generated by different version

When reading the dm cache metadata from disk, ignore the policy hints
unless they were generated by the same major version number of the same
policy module.

The hints are considered to be private data belonging to the specific
module that generated them and there is no requirement for them to make
sense to different versions of the policy that generated them.
Policy modules are all required to work fine if no previous hints are
supplied (or if existing hints are lost).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
drivers/md/dm-cache-metadata.c
drivers/md/dm-cache-metadata.h
drivers/md/dm-cache-target.c