From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail177-1.suw61.mandrillapp.com ([198.2.177.1]:59090 "EHLO mail177-1.suw61.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752287AbcCAIPj (ORCPT ); Tue, 1 Mar 2016 03:15:39 -0500 Received: from pmta06.mandrill.prod.suw01.rsglab.com (127.0.0.1) by mail177-1.suw61.mandrillapp.com id hql7qm22rtk7 for ; Tue, 1 Mar 2016 08:15:31 +0000 (envelope-from ) From: Subject: Patch "dm thin metadata: fix bug when taking a metadata snapshot" has been added to the 3.10-stable tree To: , , Cc: , Message-Id: <145681451163211@kroah.com> Date: Tue, 01 Mar 2016 08:15:32 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled dm thin metadata: fix bug when taking a metadata snapshot to the 3.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dm-thin-metadata-fix-bug-when-taking-a-metadata-snapshot.patch and it can be found in the queue-3.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 49e99fc717f624aa75ca755d6e7bc029efd3f0e9 Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Wed, 9 Dec 2015 16:23:24 +0000 Subject: dm thin metadata: fix bug when taking a metadata snapshot From: Joe Thornber commit 49e99fc717f624aa75ca755d6e7bc029efd3f0e9 upstream. When you take a metadata snapshot the btree roots for the mapping and details tree need to have their reference counts incremented so they persist for the lifetime of the metadata snap. The roots being incremented were those currently written in the superblock, which could possibly be out of date if concurrent IO is triggering new mappings, breaking of sharing, etc. Fix this by performing a commit with the metadata lock held while taking a metadata snapshot. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-thin-metadata.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -1191,6 +1191,12 @@ static int __reserve_metadata_snap(struc dm_block_t held_root; /* + * We commit to ensure the btree roots which we increment in a + * moment are up to date. + */ + __commit_transaction(pmd); + + /* * Copy the superblock. */ dm_sm_inc_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION); Patches currently in stable-queue which might be from ejt@redhat.com are queue-3.10/dm-thin-metadata-fix-bug-when-taking-a-metadata-snapshot.patch