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From: Christoph Hellwig <hch@infradead.org>
To: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	bpm@sgi.com, linux-nfs@vger.kernel.org
Subject: Re: [RFC PATCH 4/4] If 'wsync' pass datasync=1 to vfs_fsync().
Date: Thu, 4 Feb 2010 13:40:40 -0500	[thread overview]
Message-ID: <20100204184040.GA15442@infradead.org> (raw)
In-Reply-To: <1265308680.3317.19.camel@localhost>

On Thu, Feb 04, 2010 at 01:38:00PM -0500, Trond Myklebust wrote:
> > Indeed, both write_inode_now and vfs_fsync will also cause data to
> > be written.  But my understanding of nfsd is that we manage the data
> > writeout separately anyway and we care about the metadata here, which
> > the placement of these calls would suggest:
> > 
> > 	- nfsd_setattr for attribute updates
> > 	- nfsd_create for creating a new file (of any type)
> > 	- nfsd_link for adding a new link
> 
> Yes. Most operations in NFS are required to be synchronous (the only
> exception being "unstable" write requests), and so those
> fsync/write_inode_now calls are there in order to ensure that the
> metadata and/or directory contents that were changed hits the disk
> before the RPC call completes.

Yeah.  But currently both the fsync and write_inode_now calls will force
those unstable writes to disk.  I'm not sure if that is an intentional
or unintentional side-effect of those metadata operations.

  reply	other threads:[~2010-02-04 18:40 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-03 23:44 [RFC PATCH 0/4] wsync export option Ben Myers
2010-02-03 23:44 ` [RFC PATCH 1/4] Add 'wsync' " Ben Myers
2010-02-03 23:44 ` [RFC PATCH 2/4] Add datasync argument to nfsd_sync_dir() Ben Myers
2010-02-03 23:44 ` [RFC PATCH 3/4] If 'wsync' call vfs_fsync() instead of write_inode_now() Ben Myers
2010-02-03 23:44 ` [RFC PATCH 4/4] If 'wsync' pass datasync=1 to vfs_fsync() Ben Myers
2010-02-04 15:19   ` Christoph Hellwig
2010-02-04 17:20     ` bpm
2010-02-04 18:30       ` Christoph Hellwig
2010-02-04 18:38         ` Trond Myklebust
2010-02-04 18:40           ` Christoph Hellwig [this message]
2010-02-04 18:52             ` Trond Myklebust
2010-02-03 23:47 ` [ RFC PATCH 5/4 ] Add wsync export option to nfs-utils bpm
2010-02-03 23:58 ` [RFC PATCH 0/4] wsync export option Trond Myklebust
2010-02-04 15:21   ` Christoph Hellwig
2010-02-04 15:30 ` Christoph Hellwig
2010-02-04 18:15   ` bpm
2010-02-04 18:39     ` Christoph Hellwig

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