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From: Christoph Hellwig <hch@infradead.org>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: Steve Wise <swise@opengridcomputing.com>,
	linux-rdma <linux-rdma@vger.kernel.org>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH v1 05/18] xprtrdma: Avoid using Write list for small NFS READ requests
Date: Tue, 12 Apr 2016 10:01:21 -0700	[thread overview]
Message-ID: <20160412170121.GA2052@infradead.org> (raw)
In-Reply-To: <06326E24-7170-4D09-A841-08ED31D143FF@oracle.com>

On Tue, Apr 12, 2016 at 10:49:24AM -0400, Chuck Lever wrote:
> >> No, pre-4.2 Linux servers have a bug that can be fixed by
> >> applying the above commit, which shouldn't be difficult to
> >> backport.
> >> 
> >> Clients have always been allowed to send NFS READ this way.
> > 
> > But the clients might be out in a the wild.  I think we'll need at
> > least a mount option to work around them.
> 
> Huh?
> 
> I'm talking about non-Linux clients. RFC 5666 allows
> this behavior, it always has. The Linux server before
> 9d11b51ce7c1 is broken, full stop.

You are deliverately breaking exsisting and fairly recent clients.
I see why we want to do this, but there needs to be an options
that things keep working.  The idea of upgrading your client from
4.6 to 4.7 and NFS simply not working anymore with the developer
knowing it and not providing a workaround is simply not an option.

  reply	other threads:[~2016-04-12 17:01 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-11 20:10 [PATCH v1 00/18] NFS/RDMA client patches for 4.7 Chuck Lever
2016-04-11 20:10 ` [PATCH v1 01/18] sunrpc: Advertise maximum backchannel payload size Chuck Lever
2016-04-11 20:10 ` [PATCH v1 02/18] xprtrdma: Bound the inline threshold values Chuck Lever
2016-04-12 18:04   ` Anna Schumaker
2016-04-12 19:12     ` Chuck Lever
2016-04-11 20:10 ` [PATCH v1 03/18] xprtrdma: Limit number of RDMA segments in RPC-over-RDMA headers Chuck Lever
2016-04-11 20:10 ` [PATCH v1 04/18] xprtrdma: Prevent inline overflow Chuck Lever
2016-04-11 20:10 ` [PATCH v1 05/18] xprtrdma: Avoid using Write list for small NFS READ requests Chuck Lever
2016-04-11 20:35   ` Steve Wise
2016-04-11 20:38     ` Chuck Lever
2016-04-12 14:15       ` Christoph Hellwig
2016-04-12 14:49         ` Chuck Lever
2016-04-12 17:01           ` Christoph Hellwig [this message]
2016-04-12 18:08             ` Chuck Lever
2016-04-11 20:10 ` [PATCH v1 06/18] xprtrdma: Update comments in rpcrdma_marshal_req() Chuck Lever
2016-04-11 20:11 ` [PATCH v1 07/18] xprtrdma: Allow Read list and Reply chunk simultaneously Chuck Lever
2016-04-11 20:11 ` [PATCH v1 08/18] xprtrdma: Remove rpcrdma_create_chunks() Chuck Lever
2016-04-11 20:11 ` [PATCH v1 09/18] xprtrdma: Use core ib_drain_qp() API Chuck Lever
2016-04-12  4:49   ` Leon Romanovsky
2016-04-11 20:11 ` [PATCH v1 10/18] xprtrdma: Rename rpcrdma_frwr::sg and sg_nents Chuck Lever
2016-04-11 20:11 ` [PATCH v1 11/18] xprtrdma: Save I/O direction in struct rpcrdma_frwr Chuck Lever
2016-04-11 20:11 ` [PATCH v1 00/18] NFS/RDMA client patches for 4.7 Chuck Lever
2016-04-11 20:11 ` [PATCH v1 12/18] xprtrdma: Reset MRs in frwr_op_unmap_sync() Chuck Lever
2016-04-11 20:11 ` [PATCH v1 13/18] xprtrdma: Refactor the FRWR recovery worker Chuck Lever
2016-04-11 20:12 ` [PATCH v1 14/18] xprtrdma: Move fr_xprt and fr_worker to struct rpcrdma_mw Chuck Lever
2016-04-11 20:12 ` [PATCH v1 15/18] xprtrdma: Refactor __fmr_dma_unmap() Chuck Lever
2016-04-11 20:12 ` [PATCH v1 16/18] xprtrdma: Add ro_unmap_safe memreg method Chuck Lever
2016-04-11 20:12 ` [PATCH v1 17/18] xprtrdma: Remove ro_unmap() from all registration modes Chuck Lever
2016-04-11 20:12 ` [PATCH v1 18/18] xprtrdma: Faster server reboot recovery Chuck Lever

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