tree 6d14a28ef23e4633451ca5fb39ee54f0e7d4776b
parent 50887bd139b83ce4489ed865a04bf1be5559c4ad
author Joe Thornber <ejt@redhat.com> 1444395818 +0100
committer Mike Snitzer <snitzer@redhat.com> 1444396589 -0400

dm cache: fix NULL pointer when switching from cleaner policy

The cleaner policy doesn't make use of the per cache block hint space in
the metadata (unlike the other policies).  When switching from the
cleaner policy to mq or smq a NULL pointer crash (in dm_tm_new_block)
was observed.  The crash was caused by bugs in dm-cache-metadata.c
when trying to skip creation of the hint btree.

The minimal fix is to change hint size for the cleaner policy to 4 bytes
(only hint size supported).

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org