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From: Hellwig Christoph <hch@infradead.org>
To: "Myklebust, Trond" <Trond.Myklebust@netapp.com>
Cc: Hellwig Christoph <hch@infradead.org>,
	"Schumaker, Bryan" <Bryan.Schumaker@netapp.com>,
	Mailing List Linux NFS <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH 2/3] NFS: Allow for asynchronous WRITE_PLUS calls
Date: Tue, 29 Oct 2013 06:08:57 -0700	[thread overview]
Message-ID: <20131029130857.GB32094@infradead.org> (raw)
In-Reply-To: <58212CB2-A01A-43F1-8760-5ED8ED75E081@netapp.com>

On Tue, Oct 29, 2013 at 01:05:44PM +0000, Myklebust, Trond wrote:
> Imagine someone wanting to punch a 50TB hole in NTFS, for instance. It doesn't have real holes, so you'd end up needing to zero out the existing extents in that region of the file. That will take time, even with an O(nr_extents) algorithm.

That behaviour is not a hole punch, and should not be multiplexed onto
a whole punch on the wire command!  If such a use case is important
enough there should be an equivanet of the SCSI WRITE SAME command which
might make some sense to be implemented async.

We'd surely not support it in the Linux nfsd, though.

  reply	other threads:[~2013-10-29 13:08 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-28 15:00 [PATCH 0/3] NFS: Add support for fallocate and llseek Anna Schumaker
2013-10-28 15:00 ` [PATCH 1/3] NFS: Use WRITE_PLUS for hole punches Anna Schumaker
2013-10-29  7:39   ` Christoph Hellwig
2013-10-29 12:41     ` Anna Schumaker
2013-11-05  9:37   ` Christoph Hellwig
2013-10-28 15:00 ` [PATCH 2/3] NFS: Allow for asynchronous WRITE_PLUS calls Anna Schumaker
2013-10-29  7:39   ` Christoph Hellwig
2013-10-29 12:44     ` Myklebust, Trond
2013-10-29 12:48       ` Hellwig Christoph
2013-10-29 13:05         ` Myklebust, Trond
2013-10-29 13:08           ` Hellwig Christoph [this message]
2013-10-29 13:21             ` Myklebust, Trond
2013-10-29 13:24               ` Hellwig Christoph
2013-10-29 13:41                 ` Myklebust, Trond
2013-10-29 13:44                 ` J. Bruce Fields
2013-10-28 15:00 ` [PATCH 3/3] NFS: Implement SEEK Anna Schumaker

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