From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:47158 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728329AbeIHCJq (ORCPT ); Fri, 7 Sep 2018 22:09:46 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Snitzer Subject: [PATCH 4.14 31/89] dm cache metadata: save in-core policy_hint_size to on-disk superblock Date: Fri, 7 Sep 2018 23:09:25 +0200 Message-Id: <20180907210856.182448600@linuxfoundation.org> In-Reply-To: <20180907210852.341064285@linuxfoundation.org> References: <20180907210852.341064285@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Snitzer commit fd2fa95416188a767a63979296fa3e169a9ef5ec upstream. policy_hint_size starts as 0 during __write_initial_superblock(). It isn't until the policy is loaded that policy_hint_size is set in-core (cmd->policy_hint_size). But it never got recorded in the on-disk superblock because __commit_transaction() didn't deal with transfering the in-core cmd->policy_hint_size to the on-disk superblock. The in-core cmd->policy_hint_size gets initialized by metadata_open()'s __begin_transaction_flags() which re-reads all superblock fields. Because the superblock's policy_hint_size was never properly stored, when the cache was created, hints_array_available() would always return false when re-activating a previously created cache. This means __load_mappings() always considered the hints invalid and never made use of the hints (these hints served to optimize). Another detremental side-effect of this oversight is the cache_check utility would fail with: "invalid hint width: 0" Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-cache-metadata.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -362,7 +362,7 @@ static int __write_initial_superblock(st disk_super->version = cpu_to_le32(cmd->version); memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); - disk_super->policy_hint_size = 0; + disk_super->policy_hint_size = cpu_to_le32(0); __copy_sm_root(cmd, disk_super); @@ -700,6 +700,7 @@ static int __commit_transaction(struct d disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); + disk_super->policy_hint_size = cpu_to_le32(cmd->policy_hint_size); disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);