Re: [V9fs-developer] [RFC PATCH -V2 0/17] Buffered write andwriteable mmap support for 9P

From: Eric Van Hensbergen
Date: Mon Feb 07 2011 - 09:58:16 EST


On Sat, Feb 5, 2011 at 12:03 PM, Aneesh Kumar K. V
<aneesh.kumar@xxxxxxxxxxxxxxxxxx> wrote:
> On Sat,  5 Feb 2011 23:16:28 +0530, "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> wrote:
>> The patch series implement buffered write and writeable mmap for 9P
>>
>> Changes from V1:
>> a) Add fsync and syncfs support
>>
>
> I haven't yet addressed the previous review feedback from
> Miklos. http://article.gmane.org/gmane.linux.kernel/1093869
> Running 9p server and client on the same host even though possible
> is not a strong use case at this point. I will get to that later.
>

It is for a lot of the legacy cases including using 9p to access
user-space file servers. Of course, there are some long standing
issues with this for anything which re-exports the name space. Also -
most user-space file servers on the same host wouldn't want cache
support anyways.

>
> The patch series also don't address cache consistency issue that
> can arise due to direct modification in the server. I am not
> sure we need to complicate the client code for that considering
> the cache model that we follow is loose.
>

Agreed, the loose cache model doesn't respect any consistency
guarantees. Once we implement any of the more conventional cache
policies we'll have to worry about it.

-eric
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