From: Mayur Bajaj <mbajaj@maprtech.com>
To: Trond Myklebust <trondmy@primarydata.com>
Cc: List Linux NFS Mailing <linux-nfs@vger.kernel.org>
Subject: Re: NFS client behaviour with soft mount
Date: Thu, 22 Sep 2016 10:29:40 +0530 [thread overview]
Message-ID: <CAKqBuoev4=8AgLLtB-HobCEnkZ7X4H2vJrEafB-AvCPntH0Hsg@mail.gmail.com> (raw)
In-Reply-To: <093285F2-02F3-4485-AE6A-8B6409B3F03C@primarydata.com>
Thanks a lot.
On Thu, Sep 22, 2016 at 10:25 AM, Trond Myklebust
<trondmy@primarydata.com> wrote:
>
>> On Sep 22, 2016, at 00:39, Mayur Bajaj <mbajaj@maprtech.com> wrote:
>>
>> Thanks for the response.
>>
>> Incomplete data on server (NFS) is alright. I wanted to know what
>> happens to the dirty cache pages (on NFS client with soft mount and
>> sync flag not set) after the NFS client has retried for 3 times (or
>> retrans). Will the NFS client retry or give up and clean up the dirty
>> cache pages (and the dirty inode).
>
> As I said below, that behaviour is completely undefined. The page may end=
up being discarded, or it may end up persisting in the page cache. If you =
want to be certain that any remaining dirty pages in the page cache have be=
en cleaned, then you need to successfully fsync() the file to disk.
>
>>
>> Mayur
>>
>> On Wed, Sep 21, 2016 at 8:11 PM, Trond Myklebust
>> <trondmy@primarydata.com> wrote:
>>>
>>>> On Sep 21, 2016, at 10:19, Mayur Bajaj <mbajaj@maprtech.com> wrote:
>>>>
>>>> Hello,
>>>>
>>>> I have a question regarding NFS client behaviour with soft mount. I
>>>> have gone through the code but could not figure out. Can someone
>>>> please help me.
>>>>
>>>> An application is writing data via NFS client (soft mount, with sync
>>>> mount option NOT set). The Application thinks that data written was
>>>> successful but that is not the case.
>>>> The NFS client will cache all the write request and flush after some
>>>> time/threshold. The NFS sever is not responding. NFS client retries
>>>> for 3 times (or retrans) and give up as the NFS server is not
>>>> responding.
>>>>
>>>> Will this cache pages be pinned in memory for ever or freed up (marked
>>>> clean) as the operation has failed?
>>>> Will NFS client keep on retrying again?
>>>
>>>
>>> The behaviour in the above situation is completely undefined. You may h=
ave bits and pieces of data persisted on the server or not, and cached data=
may end up getting resent after the EIO was returned to the application.
>>>
>>
>
prev parent reply other threads:[~2016-09-22 4:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-21 14:19 NFS client behaviour with soft mount Mayur Bajaj
2016-09-21 14:41 ` Trond Myklebust
2016-09-22 4:39 ` Mayur Bajaj
2016-09-22 4:55 ` Trond Myklebust
2016-09-22 4:59 ` Mayur Bajaj [this message]
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