Date: Wed, 29 Mar 2017 18:13:05 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: Warner Losh <imp@bsdimp.com>, Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: John Baldwin <jhb@freebsd.org>, Ngie Cooper <ngie@freebsd.org>, src-committers <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r316132 - head/sys/boot/i386/boot2 Message-ID: <e522f8ef-7653-baad-dc7f-119dc23f4a8f@FreeBSD.org> In-Reply-To: <CANCZdfr2eRRMQy-uwXDhxT0z88CBKwtkg2e_jFBOg%2Bs_L8=FYg@mail.gmail.com> References: <201703290930.v2T9U3x9087583@repo.freebsd.org> <7448826.asYms2TLO2@ralph.baldwin.cx> <46812.1490823365@critter.freebsd.dk> <CANCZdfr2eRRMQy-uwXDhxT0z88CBKwtkg2e_jFBOg%2Bs_L8=FYg@mail.gmail.com>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --dPDir1hwWEaXiXdl6lf46os4jIEP8hw0B Content-Type: multipart/mixed; boundary="uHRVEnkA3PMOjXCxlvWMHo3Hq4lbgtp3f"; protected-headers="v1" From: Jung-uk Kim <jkim@FreeBSD.org> To: Warner Losh <imp@bsdimp.com>, Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: John Baldwin <jhb@freebsd.org>, Ngie Cooper <ngie@freebsd.org>, src-committers <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Message-ID: <e522f8ef-7653-baad-dc7f-119dc23f4a8f@FreeBSD.org> Subject: Re: svn commit: r316132 - head/sys/boot/i386/boot2 References: <201703290930.v2T9U3x9087583@repo.freebsd.org> <7448826.asYms2TLO2@ralph.baldwin.cx> <46812.1490823365@critter.freebsd.dk> <CANCZdfr2eRRMQy-uwXDhxT0z88CBKwtkg2e_jFBOg+s_L8=FYg@mail.gmail.com> In-Reply-To: <CANCZdfr2eRRMQy-uwXDhxT0z88CBKwtkg2e_jFBOg+s_L8=FYg@mail.gmail.com> --uHRVEnkA3PMOjXCxlvWMHo3Hq4lbgtp3f Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: quoted-printable On 03/29/2017 17:55, Warner Losh wrote: > On Wed, Mar 29, 2017 at 3:36 PM, Poul-Henning Kamp <phk@phk.freebsd.dk>= wrote: >> -------- >> In message <7448826.asYms2TLO2@ralph.baldwin.cx>, John Baldwin writes:= >>> On Wednesday, March 29, 2017 09:30:03 AM Ngie Cooper wrote: >> >>>> Log: >>>> Parameterize out 7680 (15 * 512) as BOOT2SIZE, similar to sys/boot= /i386/zfsboot/... >>>> >>>> This is being done to make it easier to change in the future--this= action might be >>>> needed sooner rather than later because of gcc 6.3.0 bailing, stat= ing that there >>>> is negative free space left (deficit) in the boot2 bootloader. >>>> >>>> MFC after: 2 months >>>> Sponsored by: Dell EMC Isilon >>> >>> This can't be changed. It's baked into the BSD disklabel format. >> >> No it is not, it is baked into FFS, and for UFS2 0, 8, 64 and 256K wor= ks. >=20 > Technically, this is correct. Practically, I'm not sure we can ever > really change it. There are too many tools, scripts, etc that just > know it's 8k, even though most UFS2 systems start 64k into the volume. > UFS1 systems are still around, and there the limit is a hard limit. > And if we grow it, we run the risk of corrupting data beyond the 8k > area we've traditionally used for this. >=20 > So the constants are easy enough to change and it seems like it might > be OK. However, doing it in a safe, anti-foot-shooting way will be the > real elbow grease should someone seriously contemplate the change, > especially since the foot-shooting involved has the potential for > filesystem corruption... >=20 > But gcc 6.3 likely just needs a little TLC experimenting with its > different code generation flags... Interestingly, we had the same discussion eons ago. http://docs.freebsd.org/cgi/mid.cgi?200509081418.47794.jkim FYI... Jung-uk Kim --uHRVEnkA3PMOjXCxlvWMHo3Hq4lbgtp3f-- --dPDir1hwWEaXiXdl6lf46os4jIEP8hw0B Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEl1bqgKaRyqfWXu/CfJ+WJvzb8UYFAljcMXYACgkQfJ+WJvzb 8UbRqwf+Onk9PYlWob5k8yCwrH9t3suOj2e47vUK3z3vVzMQLs7e6mvs1LZiLbaT +QS4LWlAleYh76x6wNqZQkI5hcQJBgsTWT7OSrUcARhHN5Pq1r32wUVVd+u4Nm8B hX5QDG4Lyt0rLFLTDVvEyjG3n1XlTgWFHQphrrm9+0pMF1Dw/1XZcB8EFkpoA/q1 P08F6meWB657O1lIi3aZUQ+GLnWsokAyZUv1NYtyOAGXheFSbY5Bhru03Kntmph0 H7zX5mmkClzBGqU9FHLQvqUmQfsbAhQgpD+sw/y7aj0G93NZp3Uwd5MsHqhCe/C4 xN5jz2riKfoh30ogOglFymt8KX1/yA== =k+UZ -----END PGP SIGNATURE----- --dPDir1hwWEaXiXdl6lf46os4jIEP8hw0B--
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