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From:   David Howells <dhowells@redhat.com>
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To:     Steve French <smfrench@gmail.com>
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Subject: Re: [GIT PULL] fscache rewrite -- please drop for now
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Date:   Mon, 10 Aug 2020 16:48:08 +0100
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Steve French <smfrench@gmail.com> wrote:

> 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).

You can set rsize < PAGE_SIZE?

> 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.

I've borrowed the 256K granule size used by various AFS implementations for
the moment.  A 512-byte xattr can thus hold a bitmap covering 1G of file
space.

David