From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f195.google.com ([209.85.161.195]:35220 "EHLO mail-yw0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751242AbdAWVum (ORCPT ); Mon, 23 Jan 2017 16:50:42 -0500 Received: by mail-yw0-f195.google.com with SMTP id 17so18857543ywk.2 for ; Mon, 23 Jan 2017 13:50:42 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20170123213109.GA11778@vader.DHCP.thefacebook.com> References: <20170123213109.GA11778@vader.DHCP.thefacebook.com> From: Chris Murphy Date: Mon, 23 Jan 2017 14:50:41 -0700 Message-ID: Subject: Re: read-only fs, kernel 4.9.0, fs/btrfs/delayed-inode.c:1170 __btrfs_run_delayed_items, To: Omar Sandoval Cc: Chris Murphy , Btrfs BTRFS , agruenba@redhat.com Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Mon, Jan 23, 2017 at 2:31 PM, Omar Sandoval wrote: > On Wed, Jan 18, 2017 at 02:27:13PM -0700, Chris Murphy wrote: >> On Wed, Jan 11, 2017 at 4:13 PM, Chris Murphy wrote: >> > Looks like there's some sort of xattr and Btrfs interaction happening >> > here; but as it only happens with some subvolumes/snapshots not all >> > (but 100% consistent) maybe the kernel version at the time the >> > snapshot was taken is a factor? >> >> The kernel version at the time the snapshot is taken is not a factor. >> I've taken a snapshot of a working subvolume, and booting the snapshot >> fails during startup with the fs forced readonly with kernel 4.9 and >> higher; the problem doesn't happen with kernel 4.8.17 and lower. >> >> As a further test I tried: >> >> >> git checkout tags/v4.9 >> git revert 6c6ef9f26e598fb977f60935e109cd5b266c941a >> >> But I get a failure during compile: >> >> scripts/Makefile.build:293: recipe for target 'fs/xattr.o' failed >> make[1]: *** [fs/xattr.o] Error 1 >> Makefile:988: recipe for target 'fs' failed >> make: *** [fs] Error 2 >> >> Anyway, the inability to boot snapshots means bootable rollbacks are >> broken. I think this is a serious regression, what's the next step in >> figuring out what's going on? > > Hm, so you're 100% sure that this exact commit caused the regression? > I've stared at it for a little while and am not seeing anything obvious. This is the git bisect log: https://bugzilla.kernel.org/attachment.cgi?id=251271 I don't know how to evaluate your question. If there's a test that helps answer the question, let me know. Searching for this commit brings up an lkml thread: https://lkml.org/lkml/2016/11/3/268 I haven't found the commit for that patch, so maybe it's something with the combination of that patch and the previous commit. But I see it's applied in at least 4.10-rc4 and this forced readonly event happens with 4.10-rc4. -- Chris Murphy