Date: Thu, 12 Jan 2012 23:29:36 +0200 From: Kostik Belousov <kostikbel@gmail.com> To: Mikolaj Golub <trociny@freebsd.org> Cc: "Robert N. M. Watson" <rwatson@freebsd.org>, freebsd-arch@freebsd.org Subject: Re: unix domain sockets on nullfs(5) Message-ID: <20120112212936.GB31224@deviant.kiev.zoral.com.ua> In-Reply-To: <CAOnPXZ_y5G6uEBWmfuH7qYBh%2B4Pw=O91ztCPEFCOTzWdCzx%2BRA@mail.gmail.com> References: <86sjjobzmn.fsf@kopusha.home.net> <D1B8F00C-1E0D-4916-BD4B-FBCAE28E6F22@FreeBSD.org> <86fwfnti5t.fsf@kopusha.home.net> <CAOnPXZ_y5G6uEBWmfuH7qYBh%2B4Pw=O91ztCPEFCOTzWdCzx%2BRA@mail.gmail.com>
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--w0Yn8slUAuN8hGpX Content-Type: text/plain; charset=koi8-r Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 12, 2012 at 11:17:26PM +0200, Mikolaj Golub wrote: > On Tue, Jan 10, 2012 at 10:30 PM, Mikolaj Golub <trociny@freebsd.org> wro= te: > > > > On Tue, 10 Jan 2012 14:02:34 +0000 Robert N. M. Watson wrote: > > > > =9ARNMW> (1) I don't think the new behaviour should be optional -- it w= as always > > =9ARNMW> the intent that nullfs pass through all behaviours to the unde= rlying > > =9ARNMW> layer, it's just that certain edge cases didn't appear in the = original > > =9ARNMW> implementation. Memory mapping was fixed a few years ago using= similar > > =9ARNMW> techniques. This will significantly reduce the complexity of y= our > > =9ARNMW> patch, and also avoid user confusion since it will now behave = "as > > =9ARNMW> expected". Certainly, mention in future release notes would be > > =9ARNMW> appropriate, however. > > > > I don't mind having only the new behavior, as I can't imagine where I w= ould > > need a nullfs with nosobypass option mounted and I also like when thing= s are > > simple :-). > > > > On the other hand there might be people who relied on the old behavior = and who > > would be surprised if it had changed. > > > > So, if other people agree I will remove the old behaviour to make the p= atch > > simpler. Another option would be to have sobypass by default with possi= bility > > to (re)mount fs with nosobypass. > > >=20 > If we agree to have only the new behavior then nullfs won't need modifica= tion > at all, it will work as expected automatically. The patch could be (with = updated > locking for the connect case): >=20 > http://people.freebsd.org/~trociny/VOP_UNP.1.patch I suggest to split the exclusive->shared locking change into separate patch, to be committed either before or after the VOP_UNP (better to do it before to not change the interface of VOP). You do not need local variable vp in the default implementations of vops at all, use ap->a_vp directly. --w0Yn8slUAuN8hGpX Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iEYEARECAAYFAk8PUMAACgkQC3+MBN1Mb4jA3wCgwDHY51VQBqrpGtLS27vVgq0i E6QAmwZ73vFa1/UmLcExvGm6Fo5A2TGk =ok8J -----END PGP SIGNATURE----- --w0Yn8slUAuN8hGpX--
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