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Date: Tue, 21 Aug 2012 16:59:54 +0400
From: Pavel Emelyanov <xemul@parallels.com>
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To: Boaz Harrosh <bharrosh@panasas.com>
CC: "J. Bruce Fields" <bfields@fieldses.org>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        James Bottomley <jbottomley@parallels.com>,
        Matthew Helsley <matt.helsley@gmail.com>
Subject: Re: [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper
References: <20120820183225.GB4911@fieldses.org> <20120820190606.GE27443@moon> <20120820193204.GD5779@fieldses.org> <50335261.5090504@parallels.com> <87wr0sle4v.fsf@skywalker.in.ibm.com> <503367CB.9080609@parallels.com> <20120821105424.GA7670@moon> <50336C51.60501@parallels.com> <20120821121155.GC9483@fieldses.org> <50337D87.90607@parallels.com> <20120821122908.GE9483@fieldses.org> <50338458.7090602@panasas.com>
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On 08/21/2012 04:51 PM, Boaz Harrosh wrote:
> On 08/21/2012 03:29 PM, J. Bruce Fields wrote:
> <>
> 
>> OK.  So if you don't mind the fact that there are filesystems with
>> inotify support but not filehandle support, then I think generating a
>> filehandle early as you describe would work.  I guess it's a little more
>> memory per watched inode.
>>
> 
> 
> For the minority of FSs that do not have a filehandle support it should
> be easy to generate a generic one, that should work 95% of the time.

Yup, this is how exportfd_encode_fh currently works.

> Are we guaranteed that after the checkpoint restore the version of
> the Kernel is the same as the one that did the checkpoint? If yes
> then I don't see any problem.

Strictly speaking -- no we don't. Migration should to work across kernel
versions (from older to newer). Why kernel version matters in this case?

>> --b.
> 
> 
> Cheers
> Boaz
>