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From: "bfields@fieldses.org" <bfields@fieldses.org>
To: "Shawn Lu (shawlu)" <shawlu@cisco.com>
Cc: Joshua Watt <jpewhacker@gmail.com>,
	"trond.myklebust@primarydata.com"
	<trond.myklebust@primarydata.com>,
	"anna.schumaker@netapp.com" <anna.schumaker@netapp.com>,
	"jlayton@poochiereds.net" <jlayton@poochiereds.net>,
	"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: Is "unmount -f"  worked as expected?
Date: Thu, 31 May 2018 13:34:56 -0400	[thread overview]
Message-ID: <20180531173456.GE1298@fieldses.org> (raw)
In-Reply-To: <C8362635-4E93-4C96-9827-E241565D27DF@cisco.com>

On Thu, May 31, 2018 at 04:51:49PM +0000, Shawn Lu (shawlu) wrote:
> >On 5/31/18, 8:18 AM, "bfields@fieldses.org" <bfields@fieldses.org> wrote:
>  >  > One case is involved with  cross mounted nfs from different host.
>     
>  >  Note: in theory I think there are some deadlocks possible if client and
>  >   server mount each other.  (Each host could be waiting on the other one
>  >   to process writes before it can free memory that it needs to make
>  >   progress.)
> 
> Yes.  I hope aggressive umount  will  help by setting a very short grace period and timeout before umount.

No, the deadlock isn't an unmounting problem, it's a problem that could
happen during normal operation.  I don't know if it's easy to reproduce.
You'd probably need one or both hosts to be writing to NFS very quickly.

--b.

  reply	other threads:[~2018-05-31 17:34 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-30  0:38 Is "unmount -f" worked as expected? Shawn Lu (shawlu)
2018-05-30 13:44 ` Joshua Watt
2018-05-31 15:14   ` Shawn Lu (shawlu)
2018-05-31 15:18     ` bfields
2018-05-31 16:51       ` Shawn Lu (shawlu)
2018-05-31 17:34         ` bfields [this message]
2018-05-31 18:04           ` Shawn Lu (shawlu)
2018-05-31 19:28             ` bfields
2018-05-31 20:14               ` Shawn Lu (shawlu)
2018-05-31 18:44           ` Shawn Lu (shawlu)

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