Date: Sun, 7 Aug 2022 20:06:36 -0300 From: "Dr. Rolf Jansen" <freebsd-rj@cyclaero.com> To: freebsd-arm <freebsd-arm@freebsd.org> Cc: Glen Barber <gjb@freebsd.org>, Warner Losh <imp@bsdimp.com>, "Rodney W. Grimes" <freebsd-rwg@gndrsh.dnsmgr.net>, Ed Maste <emaste@freebsd.org>, Mark Millard <marklmi@yahoo.com> Subject: Re: Looks like the arm 20220805 snapshots are still odd, so probably kern.geom.part.mbr.enforce_chs=0 was still in use Message-ID: <71BFB117-151A-4970-A9B3-9BCD14336A64@cyclaero.com> In-Reply-To: <6483BD0C-AFDF-443D-BEA2-9F599C9B8C07@cyclaero.com> References: <A1AA705B-531D-45A2-9A1F-89F759550D3A@yahoo.com> <EA1CDEC5-A29E-43C5-9437-050CDBEC2233@freebsd.org> <6AF28022-A8E7-46B3-B64E-99D217E9B6AC@yahoo.com> <99DC4046-AB8D-4D10-9475-94A8DC89DCFA@cyclaero.com> <2016951A-BF16-4780-85FF-0B77E91FBBD4@yahoo.com> <6483BD0C-AFDF-443D-BEA2-9F599C9B8C07@cyclaero.com>
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> Am 07.08.2022 um 19:51 schrieb Dr. Rolf Jansen = <freebsd-rj@cyclaero.com>: >=20 >> Am 07.08.2022 um 19:16 schrieb Mark Millard <marklmi@yahoo.com>: >>=20 >>> On 2022-Aug-7, at 14:51, Dr. Rolf Jansen <freebsd-rj@cyclaero.com> = wrote: >>>=20 >>>> Am 07.08.2022 um 16:50 schrieb Mark Millard <marklmi@yahoo.com>: >>>>=20 >>>> On 2022-Aug-7, at 12:32, Glen Barber <gjb@freebsd.org> wrote: >>>>=20 >>>>> Correct, it was set to =E2=80=9C0=E2=80=9D for these builds. >>>>>=20 >>>>> I honestly do not have any idea where the problems you are seeing = are creeping in. >>>>>=20 >>>>> Should it be set back to =E2=80=9C1=E2=80=9D? I=E2=80=99m not = sure how to proceed otherwise. >>>>=20 >>>> My guess is that if the release/tools/arm.subr line: >>>>=20 >>>> chroot ${CHROOTDIR} gpart add -t freebsd-ufs -a 64k = ${mddev}s2 >>>>=20 >>>> was instead (note the added -b use): >>>>=20 >>>> chroot ${CHROOTDIR} gpart add -t freebsd-ufs -b 64k -a = 64k ${mddev}s2 >>>>=20 >>>> then the line: >>>>=20 >>>> chroot ${CHROOTDIR} newfs -U -L rootfs /dev/${mddev}s2a >>>>=20 >>>> would work as expected and things would still be aligned: >>>> no aliasing of BSD vs. freebsd-ufs. (In part this is by >>>> prior steps already having achieved alignment of BSD.) >>>=20 >>> =46rom a strict mathematical stand point of view, -a is not = necessary when using -b with an aligned value. >>=20 >> "-a" controls more than the start offset: also the size. >>=20 >> QUOTE >> -a alignment If specified, then the gpart utility tries = to >> align start offset and partition size to = be >> multiple of alignment value. >> END QUOTE >>=20 >> I expect your statement would at most apply to the start offset, not = to >> everything "-a" does. >>=20 >>> Personally I don=E2=80=99t use the -a option of gpart anymore since = it started to do funny magics in front of face. If I remember correct, = gpart of the FreeBSD 9.x-RELEASES was still OK (or was it 8?). Nowadays, = I align all my storage media by employing -b with a reasonable value. >>>=20 >>=20 >> I've no clue of the specifics that you are referencing and so can not = check. >=20 > It started at unexpected offsets and then left unexpected space at the = end - sorry, I don=E2=80=99t use -a anymore for years, and I don=E2=80=99t= remember the very details.=20 >=20 > That said, why then would we use -b in addition to -a, if -a would = show the expected behaviour on its own. That is because either -a adds = some "funny magic" to the logic, that is stated in the man file, or = there is a bug in gpart. >=20 > Anyway, using -a and -b together bears the danger of the equation = being overestimated, namely in the case base is not a multiple (incl. 1) = of alignment. Although, that is not the case with your suggestion. -b = 64k -a 64k is OK. >=20 > Finally, I still wonder what might be the technical reason for = aligning the size. PS: Now I am in nit picking mode - "... the gpart utility tries to ..." =20 Don=E2=80=99t try it, do it! Otherwise, hasta la vista, baby! Hlv,b is meant to the -a option, and not personally.
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