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	id 02C79227A87; Tue, 21 Oct 2025 07:28:48 +0200 (CEST)
Date: Tue, 21 Oct 2025 07:28:48 +0200
From: Christoph Hellwig <hch@lst.de>
To: Chris Mason <clm@meta.com>
Cc: Christoph Hellwig <hch@lst.de>, Keith Busch <kbusch@kernel.org>,
	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: <20251021052848.GA29451@lst.de>
References: <20251020144356.693288-1-kbusch@meta.com> <20251020144522.GB30487@lst.de> <aPZNNkSOYr88-8VF@kbusch-mbp> <20251020145707.GA31743@lst.de> <7e4dcafb-80ce-458c-a7d1-520222275cd9@meta.com>
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On Mon, Oct 20, 2025 at 11:16:57AM -0400, Chris Mason wrote:
> On 10/20/25 10:57 AM, 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?
> 
> This is from me testing out AI reviews on linux-next, and they do love
> suggesting defensive programming a little too much.  I'd be happier
> with EIOs in this case but agree it's probably never going to happen.

It would be relaly useful to note in the patches if something was
found by code analys or testing and what tools are used.