Re: FUSE merging?

From: Eric Van Hensbergen (ericvh_at_gmail.com)
Date: 07/02/05

  • Next message: Tony Vroon: "Re: aic7xxx regression occuring after 2.6.12 final" 
    Date:	Sat, 2 Jul 2005 12:43:46 -0400
To: "Eric W. Biederman" <ebiederm@xmission.com>, Miklos Szeredi <miklos@szeredi.hu>

    On Sat, 2 Jul 2005 6:15 am, Eric W. Biederman wrote:
    >
    > Taking a quick glance at v9fs and fuse I fail to see how either
    > plays nicely with the page cache.
    >

    True, in fact it actively avoids using it. The previous version used
    both the page cache and the dcache with undesirable effects on synthetic
    file systems so we removed cache support. Our intention is to design a
    cache layer (similar to cfs on Plan 9) which handles cache semantics
    which can be parameterized with the appropriate cache policy depending
    on the underlying file server.

    > v9fs according to my reading of the protocol specification does
    > not have any concept of a lease. So you can't tell if you are
    > talking about a virtual filesystem where all calls should be passed
    > straight to the server or a real filesystem where you can perform
    > caching.

    While 9P contains no explicit support for leases and cacheing there is
    an informal mechanism which is used (at least for plan 9 file servers).
    If the qid.vers is 0 the file can be assumed to be a synthetic file and
    so it is not cached.

    >
    > Neither implementation seems to forward user space locks to the
    > filesystem server.
    >

    Yup. We have exclusive open semantics but not locks in the Posix
    sense. Lock support is on our 2.1 roadmap.

        -eric
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  • Next message: Tony Vroon: "Re: aic7xxx regression occuring after 2.6.12 final"

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