From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:14516 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751976AbbETSIm (ORCPT ); Wed, 20 May 2015 14:08:42 -0400 Message-ID: <555CCDA1.2040302@fb.com> Date: Wed, 20 May 2015 14:08:33 -0400 From: Chris Mason MIME-Version: 1.0 To: , , Subject: Re: [PATCH] Btrfs: fix regression in raid level conversion References: <20150520141301.GA16249@ret.masoncoding.com> <20150520170227.GM23255@twin.jikos.cz> In-Reply-To: <20150520170227.GM23255@twin.jikos.cz> Content-Type: text/plain; charset="windows-1252" Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 05/20/2015 01:02 PM, David Sterba wrote: > On Wed, May 20, 2015 at 10:13:11AM -0400, Chris Mason wrote: >> Commit 2f0810880f082fa8ba66ab2c33b02e4ff9770a5e changed >> btrfs_set_block_group_ro to avoid trying to allocate new chunks with the >> new raid profile during conversion. This fixed failures when there was >> no space on the drive to allocate a new chunk, but the metadata >> reserves were sufficient to continue the conversion. >> >> But this ended up causing a regression when the drive had plenty of >> space to allocate new chunks, mostly because reduce_alloc_profile isn't >> using the new raid profile. >> >> Fixing btrfs_reduce_alloc_profile is a bigger patch. For now, do a >> partial revert of 2f0810880, and don't error out if we hit ENOSPC. >> >> Signed-off-by: Chris Mason >> --- >> fs/btrfs/extent-tree.c | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c >> index 45e3f08..a115599 100644 >> --- a/fs/btrfs/extent-tree.c >> +++ b/fs/btrfs/extent-tree.c >> @@ -8829,6 +8829,26 @@ again: >> goto again; >> } >> >> + /* >> + * if we are changing raid levels, try to allocate a corresponding >> + * block group with the new raid level. >> + */ >> + if (!(cache->flags & BTRFS_BLOCK_GROUP_SYSTEM)) { > > This prevents to switch the system chunk in all cases. What was the > reason to do it? I thought the system chunk was being caught by check_system_chunk below, but no, its using the wrong profile. It did work when I tested, but I ran it a few times in a row and got inconsistent results. > > If I remove the check, then the conversions work in all combinations. > Eg. Thanks, I'm pushing out an updated patch without the check. -chris