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From: Christoph Hellwig <hch@lst.de>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
	Anthony Liguori <aliguori@us.ibm.com>,
	Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>,
	qemu-devel <qemu-devel@nongnu.org>,
	Ananth Narayan <ananth@linux.vnet.ibm.com>,
	Prerna Saxena <prerna@linux.vnet.ibm.com>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [Qemu-devel] [RFC][PATCH 0/2] Allow cache settings for block devices to be changed at runtime.
Date: Tue, 1 Mar 2011 13:42:54 +0100	[thread overview]
Message-ID: <20110301124254.GA29485@lst.de> (raw)
In-Reply-To: <AANLkTim2iv4zAhLsC5XzhOX9o3bMVQ866O3z-ZAWG7r4@mail.gmail.com>


The only way to change the cache settings is from the guest.  Without
that we're guranteed to lose data when going from WCE=0 to WCE=1.

I have patches to do that, and to allow changing O_DIRECT via a monitor
command, but to toggle O_SYNC via fcntl I first need to get a kernel
patch in as that's currently not allowed to be changed at runtime.

  parent reply	other threads:[~2011-03-01 12:43 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-28 11:49 [Qemu-devel] [RFC][PATCH 0/2] Allow cache settings for block devices to be changed at runtime Prerna Saxena
2011-02-28 12:07 ` [Qemu-devel] [RFC][PATCH 1/2] Add monitor command 'set-cache' to change cache settings for a block device Prerna Saxena
2011-02-28 12:11 ` [Qemu-devel] [RFC][PATCH 2/2] Extend monitor command 'info block' to display cache settings for block devices Prerna Saxena
2011-02-28 15:15   ` Kevin Wolf
2011-02-28 15:12 ` [Qemu-devel] [RFC][PATCH 0/2] Allow cache settings for block devices to be changed at runtime Kevin Wolf
2011-02-28 15:35   ` Stefan Hajnoczi
2011-02-28 15:48     ` Kevin Wolf
2011-03-01  9:55       ` Stefan Hajnoczi
2011-03-01 10:06         ` Kevin Wolf
2011-03-01 15:02           ` Chunqiang Tang
2011-03-01 13:03       ` Anthony Liguori
2011-03-01 13:22         ` Kevin Wolf
2011-03-01 15:47           ` Anthony Liguori
2011-03-01 12:42     ` Christoph Hellwig [this message]
2011-03-01 12:48       ` Stefan Hajnoczi
2011-03-01 12:50         ` Christoph Hellwig
2011-03-01 19:13           ` Anthony Liguori
2011-03-02  7:57             ` Kevin Wolf
2011-03-01 12:52       ` Kevin Wolf

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