[sheepdog] [PATCH] disk cache: drop O_DSYNC only when O_DIRECT is set

[MORITA Kazutaka]

At Tue, 30 Oct 2012 19:26:59 +0800,
Liu Yuan wrote:
> 
> As for sheepdog, currently we always use O_DIRECT with data objects, so
> we don't have this kind of duplicate problem at all.As you mentioned, we
> only drop O_DIRECT for inode object, which never have a chance to be
> cached in Guest memory. No?

Hmm, you are right.  Seems that I was obsessed with using only disk
cache.  Actually, dropping a page cache for each inode update causes a
severe performance degradation and it's not what users want.

Thanks,

Kazutaka