From 5b564d80f8bc21094c0cd2b19b679d983aabcc29 Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Fri, 13 Dec 2013 12:31:08 +0000 Subject: [PATCH] dm space map: disallow decrementing a reference count below zero The old behaviour, returning -EINVAL if a ref_count of 0 would be decremented, was removed in commit f722063 ("dm space map: optimise sm_ll_dec and sm_ll_inc"). To fix this regression we return an error code from the mutator function pointer passed to sm_ll_mutate() and have dec_ref_count() return -EINVAL if the old ref_count is 0. Add a DMERR to reflect the potential seriousness of this error. Also, add missing dm_tm_unlock() to sm_ll_mutate()'s error path. With this fix the following dmts regression test now passes: dmtest run --suite cache -n /metadata_use_kernel/ The next patch fixes the higher-level dm-array code that exposed this regression. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org # 3.12+ --- Reading git-format-patch failed