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From: Vivek Goyal <vgoyal@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: Alex Bligh <alex@alex.org.uk>, linux-fsdevel@vger.kernel.org
Subject: Re: Questions on block drivers, REQ_FLUSH and REQ_FUA
Date: Wed, 25 May 2011 15:15:23 -0400	[thread overview]
Message-ID: <20110525191523.GC6724@redhat.com> (raw)
In-Reply-To: <BANLkTimmhx7TB70f6g5Xoh_i51-t7Q50fQ@mail.gmail.com>

On Wed, May 25, 2011 at 06:43:14PM +0200, Tejun Heo wrote:

[..]
> 
> * Write data, REQ_FUA - Write should be completed before FLUSH is
> issued - ie. the write data should be on platter along with previously
> completed writes on bio completion.

Tejun,

I have a confusion regarding the following statement.

"along with previously completed writes on bio completion"

I thought REQ_FUA just gurantees that bio/req carrying REQ_FUA flag is
on disk platter. It does not gurantee anything about other requests 
which completed before this bio/req and might still be in non volatile
caches of device.

Thanks
Vivek

      parent reply	other threads:[~2011-05-25 19:15 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-24 21:29 Questions on block drivers, REQ_FLUSH and REQ_FUA Alex Bligh
2011-05-24 22:32 ` Vivek Goyal
2011-05-24 22:37   ` Vivek Goyal
2011-05-25  8:06   ` Alex Bligh
2011-05-25  8:59   ` Tejun Heo
2011-05-25 15:54     ` Alex Bligh
2011-05-25 16:43       ` Tejun Heo
2011-05-25 17:43         ` Alex Bligh
2011-05-25 19:10           ` Vivek Goyal
2011-05-25 19:58             ` Alex Bligh
2011-05-25 19:15         ` Vivek Goyal [this message]

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