linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Trond Myklebust <trond.myklebust@fys.uio.no>
To: Xin Zhao <uszhaoxin@gmail.com>
Cc: Matthew Wilcox <matthew@wil.cx>, Neil Brown <neilb@suse.de>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org
Subject: Re: Urgent help needed on an NFS question, please help!!!
Date: Thu, 10 Aug 2006 13:28:41 -0400	[thread overview]
Message-ID: <1155230922.10547.61.camel@localhost> (raw)
In-Reply-To: <4ae3c140608100923j1ffb5bb5qa776bff79365874c@mail.gmail.com>

On Thu, 2006-08-10 at 12:23 -0400, Xin Zhao wrote:
> That makes sense.
> 
> Can we make the following two conclusions?
> 1. In a single machine, inode+dev ID+i_generation can uniquely identify a file

Not really. The device id is frequently subject to change on server
reboot or device disconnect/reconnect.

> 2. Given a stored file handle and an inode object received from the
> server,  an NFS client can safely determine whether this inode
> corresponds to the file handle by checking the inode+dev+i_generation.

No! The file handle is an opaque bag of bytes as far as clients are
concerned. If you change the server, then the filehandle format can and
will change. On linux, even changing the setting of the subtree_checking
export option will suffice to change the filehandle.

Cheers,
   Trond


  parent reply	other threads:[~2006-08-10 17:29 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-10  5:04 Urgent help needed on an NFS question, please help!!! Xin Zhao
2006-08-10  5:11 ` Neil Brown
2006-08-10  5:54   ` Xin Zhao
2006-08-10  6:03     ` Neil Brown
2006-08-10 15:15       ` Xin Zhao
2006-08-10 16:11         ` Matthew Wilcox
2006-08-10 16:23           ` Xin Zhao
2006-08-10 16:54             ` Matthew Wilcox
2006-08-10 17:08               ` Xin Zhao
2006-08-10 17:38                 ` Trond Myklebust
2006-08-10 17:28             ` Trond Myklebust [this message]
2006-08-10 18:02               ` Xin Zhao
2006-08-10 19:59                 ` Trond Myklebust
2006-08-10 22:25                   ` Xin Zhao
2006-08-11  0:44                     ` Trond Myklebust
2006-08-10 22:28                   ` Xin Zhao
2006-08-11  0:38                     ` Trond Myklebust
2006-08-10 23:42                   ` Bryan Henderson
2006-08-10 17:50             ` Bryan Henderson
2006-08-10 18:15               ` Xin Zhao
2006-08-11  0:07                 ` Bryan Henderson
2006-08-10 21:00             ` Peter Staubach
2006-08-10  6:04   ` Xin Zhao
2006-08-10  6:15     ` Xin Zhao

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1155230922.10547.61.camel@localhost \
    --to=trond.myklebust@fys.uio.no \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=matthew@wil.cx \
    --cc=neilb@suse.de \
    --cc=uszhaoxin@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).