From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jamie Lokier <jamie@shareable.org>
Subject: Re: adding proper O_SYNC/O_DSYNC, was Re: O_DIRECT and barriers
Date: Sat, 29 Aug 2009 00:06:23 +0100
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Cc: Ulrich Drepper <drepper@redhat.com>, linux-fsdevel@vger.kernel.org,
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To: Christoph Hellwig <hch@infradead.org>
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Christoph Hellwig wrote:
>  - given that our current O_SYNC really is and always has been actuall
>    Posix O_DSYNC

Are you sure about this?

>>From http://www-01.ibm.com/support/docview.wss?uid=isg1IZ01704 :

    Error description

       LINUX O_DIRECT/O_SYNC TAKES TOO MANY IOS

    Problem summary

       On AIX, the O_SYNC and O_DSYNC are different values and
       performance improvement are available because the inode does
       not need to be flushed for mtime changes only.
       On Linux the flags are the same, so performance is lost.
       when databases open files with O_DIRECT and O_SYNC.

-- Jamie