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From: Christoph Hellwig <hch@infradead.org>
Subject: Re: Why is O_DSYNC on linux so slow / what's wrong with my SSD?
Date: Wed, 20 Nov 2013 05:38:33 -0800
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Cc: Christoph Hellwig <hch@infradead.org>,
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	linux-fsdevel@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
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To: Chinmay V S <cvs268@gmail.com>
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On Wed, Nov 20, 2013 at 07:04:15PM +0530, Chinmay V S wrote:
> Note that SYNC/DSYNC on a filesystem(eg. ext2/3/4) does NOT issue a
> CMD_FLUSH. The "SYNC" via filesystem, simply guarantees that the data
> is sent to the disk and not really flushed to the disk.

While this used to be the case for ext2 and ext3 this has never been
true for the modern filesystem, and has been fixed for ext3 quite
a while ago.