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Date: Mon, 20 Oct 2025 09:05:46 -0600
From: Keith Busch <kbusch@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@meta.com>, dsterba@suse.com, cem@kernel.org,
	linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org,
	Chris Mason <clm@fb.com>
Subject: Re: [PATCH 1/2] xfs: handle bio split errors during gc
Message-ID: <aPZPyme5tYvZc9GR@kbusch-mbp>
References: <20251020144356.693288-1-kbusch@meta.com>
 <20251020144522.GB30487@lst.de>
 <aPZNNkSOYr88-8VF@kbusch-mbp>
 <20251020145707.GA31743@lst.de>
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In-Reply-To: <20251020145707.GA31743@lst.de>

On Mon, Oct 20, 2025 at 04:57:07PM +0200, Christoph Hellwig wrote:
> On Mon, Oct 20, 2025 at 08:54:46AM -0600, Keith Busch wrote:
> > > Ugg, how?  If that actually happens we're toast, so we should find a
> > > way to ensure it does not happen.
> > 
> > You'd have to attempt sending an invalid bvec, like something that can't
> > DMA map because you have a byte aligned offset, or the total size is
> > smaller than the block device's.
> > 
> > Not that you're doing anything like that here. This condition should
> > never occur in this path because the bio vectors are all nicely aligned.
> > It's just for completeness to ensure it doesn't go uncaught for every
> > bio split caller.
> 
> So this is just from code inspection and you did not actually hit
> such a case?

Correct, no one actually hit such errors. Same is true for the btrfs
patch.