From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:63119 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752651AbaJWInR (ORCPT ); Thu, 23 Oct 2014 04:43:17 -0400 Message-ID: <5448C006.1070808@cn.fujitsu.com> Date: Thu, 23 Oct 2014 16:44:54 +0800 From: Miao Xie Reply-To: MIME-Version: 1.0 To: Josef Bacik , Subject: Re: [PATCH] Btrfs: don't do async reclaim during log replay V2 References: <1411054037-20136-1-git-send-email-jbacik@fb.com> In-Reply-To: <1411054037-20136-1-git-send-email-jbacik@fb.com> Content-Type: text/plain; charset="utf-8" Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, 18 Sep 2014 11:27:17 -0400, Josef Bacik wrote: > Trying to reproduce a log enospc bug I hit a panic in the async reclaim code > during log replay. This is because we use fs_info->fs_root as our root for > shrinking and such. Technically we can use whatever root we want, but let's > just not allow async reclaim while we're doing log replay. Thanks, Why not move the code of fs_root initialization to the front of log replay? I think it is better than the fix way in this patch because the async reclaimer can help us do some work. Thanks Miao > > Signed-off-by: Josef Bacik > --- > V1->V2: use fs_info->log_root_recovering instead, didn't notice this existed > before. > > fs/btrfs/extent-tree.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index 28a27d5..44d0497 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -4513,7 +4513,13 @@ again: > space_info->flush = 1; > } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) { > used += orig_bytes; > - if (need_do_async_reclaim(space_info, root->fs_info, used) && > + /* > + * We will do the space reservation dance during log replay, > + * which means we won't have fs_info->fs_root set, so don't do > + * the async reclaim as we will panic. > + */ > + if (!root->fs_info->log_root_recovering && > + need_do_async_reclaim(space_info, root->fs_info, used) && > !work_busy(&root->fs_info->async_reclaim_work)) > queue_work(system_unbound_wq, > &root->fs_info->async_reclaim_work); >