Date: Wed, 7 Nov 2018 13:31:38 -0700 From: Warner Losh <imp@bsdimp.com> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: "Rodney W. Grimes" <rgrimes@freebsd.org>, Ian Lepore <ian@freebsd.org>, Maxim Sobolev <sobomax@freebsd.org>, src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org, Pawel Jakub Dawidek <pjd@freebsd.org> Subject: Re: svn commit: r340187 - head/sys/geom Message-ID: <CANCZdfr0gvfoeDfQu5L0QuGV8L%2BfJeQ=HQiWeaQuosP5fw3YyQ@mail.gmail.com> In-Reply-To: <1603.1541622015@critter.freebsd.dk> References: <1541606248.52306.42.camel@freebsd.org> <201811071606.wA7G6mQW001639@pdx.rh.CN85.dnsmgr.net> <CANCZdfrK-7vBETkhfQ9KkM4usrvjVh8wS_OZJiDmH5336DTsqQ@mail.gmail.com> <1603.1541622015@critter.freebsd.dk>
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On Wed, Nov 7, 2018 at 1:20 PM Poul-Henning Kamp <phk@phk.freebsd.dk> wrote: > -------- > In message < > CANCZdfrK-7vBETkhfQ9KkM4usrvjVh8wS_OZJiDmH5336DTsqQ@mail.gmail.com> > , Warner Losh writes: > > >BIO_FLUSH is primarily done to force ordering points, > > Originally BIO_FLUSH was defined the way it is, to make it possible > to flush an isolated specified range on providers which support that > so that fsync(2) could be implemented that way. > > I can't remember the exact semantics of the two "magic" flush > operations (off=0,len=0) and (off=end,len=0) but they were different > from each other in some important aspect (Pawel?) > I couldn't find any place where the different types of flush are differentiated (nothing in CAM for sure), though I suppose I could have missed something. All the CAM drivers just use it to push data to the device and don't look at the flags. Warner
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