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Date: Thu, 8 Nov 2012 11:03:22 +0800
Message-ID: <CA+res+SD_mradA6grZz_80uWiidb_r9Kv_aW8rXVXpNLSozjWA@mail.gmail.com>
Subject: Re: hang problem when umount a nfs point
From: Jack Wang <jack.wang.usish@gmail.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: =?UTF-8?Q?Mart=C3=ADn_Cigorraga?= <msx@archlinux.us>, dahai_tian@usish.com,
        linux-nfs@vger.kernel.org
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2012/11/8 J. Bruce Fields <bfields@fieldses.org>:
> On Wed, Nov 07, 2012 at 09:05:51AM +0800, Jack Wang wrote:
>> 2012/11/7 Martín Cigorraga <msx@archlinux.us>:
>> > On Mon, Nov 5, 2012 at 10:27 PM, Jack Wang <jack.wang.usish@gmail.com>
>> > wrote:
>> >>
>> >> Hi all,
>> >>
>> >> Anyone who can kindly give some suggestion? or we just put question to
>> >> the wrong list?
>> >>
>> >> Thanks.
>> >>
>> >> Jack
>> >>
>> >> 2012/11/1 dahai_tian <dahai_tian@usish.com>:
>> >> > Hi all:
>> >> >         I mount a local directory to a nfs server. When nfs server is
>> >> > stopped
>> >> > for some accidental cause, I try to umount the mount point, the umount
>> >> > command will hang and 'time out' messages are continually printed in the
>> >> > terminal. How can I avoid hanging in this case? BTW, This issue does not
>> >> > exist when I changed nfs version from 4 to 3.
>> >> >         Look forward to your response, thanks!
>>
>> >
>> > Hi Jack, use the -l (lazy) switch:
>> > # umount -l {your mounted nfs share}
>> >
>> > Also, I wouldn't recommend 'just to kill' the NFS proces(ses) as it (them)
>> > may leave shared memory a mess.
>> > (And I would like to see how do you make to mount any NFS share again
>> > without booting)
>>
>> Thanks Martin for kindly help.
>>
>> umount -l did work, but why nfsv3 do not have this problem?
>
> I don't know what it is exactly.  But in general I wouldn't expect
> umount to work when the server's unavailable.
>
> --b.

Thanks for your time Bruce, but there are chance the server
unavailable , why you think umount don't work is expected?

Jack