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References: <20230307143410.28031-1-hch@lst.de>
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From:   Andreas Gruenbacher <agruenba@redhat.com>
Date:   Tue, 7 Mar 2023 16:23:50 +0100
Message-ID: <CAHc6FU4G5S+5S+1OdatY3apQvmDcvzOQSPPPQdQZTwMNjSq5tw@mail.gmail.com>
Subject: Re: [Cluster-devel] return an ERR_PTR from __filemap_get_folio v3
To:     Christoph Hellwig <hch@lst.de>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Matthew Wilcox <willy@infradead.org>,
        Hugh Dickins <hughd@google.com>, linux-xfs@vger.kernel.org,
        linux-nilfs@vger.kernel.org, cluster-devel@redhat.com,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        linux-ext4@vger.kernel.org, linux-afs@lists.infradead.org,
        linux-btrfs@vger.kernel.org
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On Tue, Mar 7, 2023 at 4:07=E2=80=AFPM Christoph Hellwig <hch@lst.de> wrote=
:
> __filemap_get_folio and its wrappers can return NULL for three different
> conditions, which in some cases requires the caller to reverse engineer
> the decision making.  This is fixed by returning an ERR_PTR instead of
> NULL and thus transporting the reason for the failure.  But to make
> that work we first need to ensure that no xa_value special case is
> returned and thus return the FGP_ENTRY flag.  It turns out that flag
> is barely used and can usually be deal with in a better way.

Thanks for working on this cleanup; looking good at a first glance.

Andreas