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From:   Steve French <smfrench@gmail.com>
Date:   Mon, 10 Aug 2020 10:34:21 -0500
Message-ID: <CAH2r5msKipj1exNUDaSUN7h0pjanOenhSg2=EWYMv_h15yKtxg@mail.gmail.com>
Subject: Re: [GIT PULL] fscache rewrite -- please drop for now
To:     David Howells <dhowells@redhat.com>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Matthew Wilcox <willy@infradead.org>,
        Christoph Hellwig <hch@lst.de>,
        Jeff Layton <jlayton@redhat.com>,
        Dave Wysochanski <dwysocha@redhat.com>,
        Trond Myklebust <trondmy@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        Steve French <sfrench@samba.org>,
        Eric Van Hensbergen <ericvh@gmail.com>,
        linux-cachefs@redhat.com, linux-afs@lists.infradead.org,
        linux-nfs <linux-nfs@vger.kernel.org>,
        CIFS <linux-cifs@vger.kernel.org>, ceph-devel@vger.kernel.org,
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        LKML <linux-kernel@vger.kernel.org>
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cifs.ko also can set rsize quite small (even 1K for example, although
that will be more than 10x slower than the default 4MB so hopefully no
one is crazy enough to do that).   I can't imagine an SMB3 server
negotiating an rsize or wsize smaller than 64K in today's world (and
typical is 1MB to 8MB) but the user can specify a much smaller rsize
on mount.  If 64K is an adequate minimum, we could change the cifs
mount option parsing to require a certain minimum rsize if fscache is
selected.

On Mon, Aug 10, 2020 at 10:17 AM David Howells <dhowells@redhat.com> wrote:
>
> Hi Linus,
>
> Can you drop the fscache rewrite pull for now.  We've seem an issue in NFS
> integration and need to rework the read helper a bit.  I made an assumption
> that fscache will always be able to request that the netfs perform a read of a
> certain minimum size - but with NFS you can break that by setting rsize too
> small.
>
> We need to make the read helper able to make multiple netfs reads.  This can
> help ceph too.
>
> Thanks,
> David
>


-- 
Thanks,

Steve