From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D96021A00DF for ; Fri, 11 Oct 2024 17:13:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728666784; cv=none; b=p39lR8l3Ud96Bzr6OM3pOxY3BDU7WwHz8fu7G3YTCOQ2TuYzMTibqmwn/lhKszWvVShz3tnmkwmBkymkJv4wH/RlODUaS1m5i0i64NZ7YxLRcxNR5F0MZmxQmESLxaRkvx4euadjTCBGFYcQHognPoXTvHTFOdajURh/RfxxHBI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728666784; c=relaxed/simple; bh=84UJpo00BunE/Rhb5VjBM2R82vWUvAlukcp0iBu/3KM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=E43hbMQVzQxVo+RYXbSkz4OyzTOAQo8kfwVpEA7OrC2CV7wbVX1rzqsRt+tN93NxWJ9KOWzDanNTgBLRhzVPdPEnQlBZSYhXKdooYgtlH6vJ/HZ6Bod/3NydBSVK/f2WDuwEDEjNfGgvjKi96Wl7xYxravvsAoLF816hFmsg368= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=d1xhxfR7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="d1xhxfR7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59F81C4CEC3; Fri, 11 Oct 2024 17:13:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728666784; bh=84UJpo00BunE/Rhb5VjBM2R82vWUvAlukcp0iBu/3KM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=d1xhxfR7Lpw1cNC6ROYBxxLIzOoBHwgyo+aI/hLCmDtRqZGVtsBG1j0xEy7ZFiL1D +kXlN1GXW3U6fLE965nK0F9FMamYKsd3DV9iirtlM8eUsByveGbYkqVK53JJNENyaT qiNYq8OEOP4dt51mDucan1ZpsVGsDVrvY25qbaoIaWUvIU+NYns1Q5bymvx5Y+02Ef VR/2A9t5gL9dcwY3E2L12FnZ/OXbWD3YY2XmM2SzQY85cbY/k4Ztaco9O5wfmozTbt 174l66AAq1xpbgN4/+DQVwoE0ZL3JImdzV9QQuZJzBHKVrILkmLc2ArAG0jRrpt+DO lj1ZvaTZqEPYw== Date: Fri, 11 Oct 2024 10:13:03 -0700 From: "Darrick J. Wong" To: Brian Foster Cc: Christoph Hellwig , Chandan Babu R , linux-xfs@vger.kernel.org Subject: Re: [PATCH 6/7] xfs: don't update file system geometry through transaction deltas Message-ID: <20241011171303.GB21853@frogsfrogsfrogs> References: <20240930164211.2357358-1-hch@lst.de> <20240930164211.2357358-7-hch@lst.de> <20241011075709.GC2749@lst.de> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Oct 11, 2024 at 10:02:16AM -0400, Brian Foster wrote: > On Fri, Oct 11, 2024 at 09:57:09AM +0200, Christoph Hellwig wrote: > > On Thu, Oct 10, 2024 at 10:05:53AM -0400, Brian Foster wrote: > > > Ok, so we don't want geometry changes transactions in the same CIL > > > checkpoint as alloc related transactions that might depend on the > > > geometry changes. That seems reasonable and on a first pass I have an > > > idea of what this is doing, but the description is kind of vague. > > > Obviously this fixes an issue on the recovery side (since I've tested > > > it), but it's not quite clear to me from the description and/or logic > > > changes how that issue manifests. > > > > > > Could you elaborate please? For example, is this some kind of race > > > situation between an allocation request and a growfs transaction, where > > > the former perhaps sees a newly added AG between the time the growfs > > > transaction commits (applying the sb deltas) and it actually commits to > > > the log due to being a sync transaction, thus allowing an alloc on a new > > > AG into the same checkpoint that adds the AG? > > > > This is based on the feedback by Dave on the previous version: > > > > https://lore.kernel.org/linux-xfs/Zut51Ftv%2F46Oj386@dread.disaster.area/ > > > > Ah, Ok. That all seems reasonably sane to me on a first pass, but I'm > not sure I'd go straight to this change given the situation... > > > Just doing the perag/in-core sb updates earlier fixes all the issues > > with my test case, so I'm not actually sure how to get more updates > > into the check checkpoint. I'll try your exercisers if it could hit > > that. > > > > Ok, that explains things a bit. My observation is that the first 5 > patches or so address the mount failure problem, but from there I'm not > reproducing much difference with or without the final patch. Does this change to flush the log after committing the new sb fix the recovery problems on older kernels? I /think/ that's the point of this patch. > Either way, > I see aborts and splats all over the place, which implies at minimum > this isn't the only issue here. Ugh. I've recently noticed the long soak logrecovery test vm have seen a slight tick up in failure rates -- random blocks that have clearly had garbage written to them such that recovery tries to read the block to recover a buffer log item and kaboom. At this point it's unclear if that's a problem with xfs or somewhere else. :( > So given that 1. growfs recovery seems pretty much broken, 2. this > particular patch has no straightforward way to test that it fixes > something and at the same time doesn't break anything else, and 3. we do I'm curious, what might break? Was that merely a general comment, or do you have something specific in mind? (iows: do you see more string to pull? :)) > have at least one fairly straightforward growfs/recovery test in the > works that reliably explodes, personally I'd suggest to split this work > off into separate series. > > It seems reasonable enough to me to get patches 1-5 in asap once they're > fully cleaned up, and then leave the next two as part of a followon > series pending further investigation into these other issues. As part of > that I'd like to know whether the recovery test reproduces (or can be > made to reproduce) the issue this patch presumably fixes, but I'd also > settle for "the grow recovery test now passes reliably and this doesn't > regress it." But once again, just my .02. Yeah, it's too bad there's no good way to test recovery with older kernels either. :( --D > Brian > >