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From: Valerie Aurora <vaurora@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>,
	Trond Myklebust <Trond.Myklebust@netapp.com>,
	"J. Bruce Fields" <bfields@fieldses.org>
Cc: Neil Brown <neilb@suse.de>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	viro@zeniv.linux.org.uk, jblunck@suse.de, hch@infradead.org
Subject: Re: [PATCH 0/5] hybrid union filesystem prototype
Date: Tue, 31 Aug 2010 15:18:46 -0400	[thread overview]
Message-ID: <20100831191846.GA5759@shell> (raw)
In-Reply-To: <E1Oq3Lz-0004D8-MP@pomaz-ex.szeredi.hu>

On Mon, Aug 30, 2010 at 02:20:47PM +0200, Miklos Szeredi wrote:
> On Mon, 30 Aug 2010, Neil Brown wrote:
> 
> > Val has been following that approach and asking if it is possible to make an
> > NFS filesystem really-truly read-only. i.e. no changes.
> > I don't believe it is.
> 
> Perhaps it doesn't matter.  The nasty cases can be prevented by just
> disallowing local modification.  For the rest NFS will return ESTALE:
> "though luck, why didn't you follow the rules?"

I agree: Ask the server to keep it read-only, but also detect if it
lied to prevent kernel bugs on the client.

Is detecting ESTALE and failing the mount sufficient to detect all
cases of a cached directory being altered?  I keep trying to trap an
NFS developer and beat the answer out of him but they usually get hung
up on the impossibility of 100% enforcement of the read-only server
option. (Agreed, impossible, just give the sysadmin a mount option so
that it doesn't happen accidentally.)

-VAL

  reply	other threads:[~2010-08-31 19:18 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-26 18:33 [PATCH 0/5] hybrid union filesystem prototype Miklos Szeredi
2010-08-26 18:33 ` [PATCH 1/5] vfs: implement open "forwarding" Miklos Szeredi
2010-08-26 18:33 ` [PATCH 2/5] vfs: make i_op->permission take a dentry instead of an inode Miklos Szeredi
2010-08-26 20:24   ` David P. Quigley
2010-08-27  4:11     ` Neil Brown
2010-08-27 18:13       ` David P. Quigley
2010-08-27 19:21         ` Valerie Aurora
2010-08-27 18:31       ` David P. Quigley
2010-08-26 18:33 ` [PATCH 3/5] vfs: add flag to allow rename to same inode Miklos Szeredi
2010-08-26 18:33 ` [PATCH 4/5] vfs: export do_splice_direct() to modules Miklos Szeredi
2010-08-26 18:33 ` [PATCH 5/5] union: hybrid union filesystem prototype Miklos Szeredi
2010-09-01 21:42   ` Valerie Aurora
2010-09-02  9:19     ` Miklos Szeredi
2010-09-02 21:33       ` Valerie Aurora
2010-09-03  5:10         ` Neil Brown
2010-09-03  9:16           ` Miklos Szeredi
2010-09-09 16:02             ` David P. Quigley
2010-09-03  8:52         ` Miklos Szeredi
2010-09-02 21:42   ` Valerie Aurora
2010-09-03 12:31     ` Miklos Szeredi
2010-08-27  7:05 ` [PATCH 0/5] " Neil Brown
2010-08-27  8:47   ` Miklos Szeredi
2010-08-27 11:35     ` Neil Brown
2010-08-27 16:53       ` Miklos Szeredi
2010-08-29  4:42         ` Neil Brown
2010-08-30 10:18           ` Miklos Szeredi
2010-08-30 11:40             ` Neil Brown
2010-08-30 12:20               ` Miklos Szeredi
2010-08-31 19:18                 ` Valerie Aurora [this message]
2010-08-31 20:19                   ` Trond Myklebust
2010-09-01  1:56                     ` Valerie Aurora
2010-09-01  4:04                       ` Trond Myklebust
2010-09-01  4:33               ` Neil Brown
2010-09-01 20:11                 ` Miklos Szeredi
2010-08-31 19:29             ` Valerie Aurora
2010-09-02 13:15             ` Jan Engelhardt
2010-09-02 13:32               ` Neil Brown
2010-09-02 14:25                 ` Jan Engelhardt
2010-09-02 14:28                   ` Miklos Szeredi
2010-09-08 19:47                     ` David P. Quigley
2010-09-23 13:18                   ` Jan Engelhardt
2010-09-23 19:22                     ` Valerie Aurora
2010-08-30 18:38       ` Valerie Aurora
2010-08-30 23:12         ` Neil Brown
2010-08-31 11:00           ` Miklos Szeredi
2010-08-31 11:24             ` Neil Brown
2010-08-31 15:05               ` Kyle Moffett
2010-08-31 20:36                 ` Valerie Aurora

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