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From: Jeff Moyer <jmoyer@redhat.com>
To: Linux Kernel Mailing <linux-kernel@vger.kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Subject: blkdev_issue_flush really issues a WRITE_BARRIER -- is that okay?
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Date: Mon, 12 Oct 2009 13:31:25 -0400
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Hi,

While looking though Christoph's patch to call blkdev_issue_flush for
fsync on block devices, I noticed that it only issues a WRITE_BARRIER.
I don't see how that guarantees that data is on stable storage.  Am I
missing something?  Shouldn't this translate to a FLUSH CACHE or
SYNCHRONIZE CACHE command?

My apologies if this has been discussed before.

Thanks!
Jeff