Date: Fri, 3 Apr 2009 13:29:33 +0800 (CST) From: Tai-hwa Liang <avatar@mmlab.cse.yzu.edu.tw> To: Marcel Moolenaar <xcllnt@mac.com> Cc: freebsd-current@freebsd.org Subject: Re: Removal of GEOM_BSD, GEOM_MBR, GEOM_PC98 and GEOM_SUNLABEL Message-ID: <0904031327195.78401@www.mmlab.cse.yzu.edu.tw> In-Reply-To: <A821815A-63BE-4354-A8A9-6C1C8D277422@mac.com> References: <DED07257-A1C7-4504-9A9E-CAAC2A9737D6@mac.com> <95891.1238477069@critter.freebsd.dk> <20090331133132.1e191836@ernst.jennejohn.org> <gqt3um$f77$3@ger.gmane.org> <20090331155542.74d89d64@ernst.jennejohn.org> <60084D1E-9F64-463A-A8E9-7A237D5C7661@mac.com> <0904011910169.29800@www.mmlab.cse.yzu.edu.tw> <DC771BC5-F356-4D81-9082-91C922CCBF38@mac.com> <0904020940371.36257@www.mmlab.cse.yzu.edu.tw> <4CCDEFD6-830E-4C8F-B7A2-B7878F8842BE@mac.com> <0904021314574.37737@www.mmlab.cse.yzu.edu.tw> <E6347C70-099B-494A-89E2-8CBDDAA36A85@mac.com> <09040309313414.76643@www.mmlab.cse.yzu.edu.tw> <A821815A-63BE-4354-A8A9-6C1C8D277422@mac.com>
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On Thu, 2 Apr 2009, Marcel Moolenaar wrote:
[...]
> It looks like you have a boot menu entry at 0x1b6. Can you
> try the following patch:
>
> Index: g_part_ebr.c
> ===================================================================
> --- g_part_ebr.c (revision 190655)
> +++ g_part_ebr.c (working copy)
> @@ -403,9 +403,13 @@
> if (magic != DOSMAGIC)
> goto out;
>
> - /* The sector is all zeroes, except for the partition entries. */
> + /*
> + * The sector is all zeroes, except for the partition entries
> + * and a possible IBM Boot Manager menu entry. The menu entry
> + * is 9 bytes in length and preceeds the partition entries.
> + */
> sum = 0;
> - for (index = 0; index < DOSPARTOFF; index++)
> + for (index = 0; index < DOSPARTOFF - 9; index++)
> sum += buf[index];
> if (sum != 0)
> goto out;
>
>
> The real fix will be a bit more involved, because we should
> avoid wiping out the boot menu entry on a write. But at least
> with the patch you should be able to read the EBR.
Much better. I can see extended partition nodes after booting with the
patched kernel:
# ls -la /dev/ad*
crw-r----- 1 root operator 0, 73 4 3 21:12 /dev/ad0
crw-r----- 1 root operator 0, 79 4 3 21:12 /dev/ad0s1
crw-r----- 1 root operator 0, 80 4 3 21:12 /dev/ad0s2
crw-r----- 1 root operator 0, 82 4 3 21:12 /dev/ad0s2a
crw-r----- 1 root operator 0, 83 4 3 21:12 /dev/ad0s2b
crw-r----- 1 root operator 0, 84 4 3 21:12 /dev/ad0s2d
crw-r----- 1 root operator 0, 85 4 3 21:12 /dev/ad0s2e
crw-r----- 1 root operator 0, 81 4 3 21:12 /dev/ad0s3
crw-r----- 1 root operator 0, 86 4 3 21:12 /dev/ad0s3+00000001
crw-r----- 1 root operator 0, 88 4 3 21:12 /dev/ad0s3+000410a1
crw-r----- 1 root operator 0, 90 4 3 21:12 /dev/ad0s3+00103bf1
crw-r----- 1 root operator 0, 92 4 3 21:12 /dev/ad0s3+0017cda1
lrwxr-xr-x 1 root wheel 14 4 3 21:12 /dev/ad0s5 -> ad0s3+00000001
lrwxr-xr-x 1 root wheel 14 4 3 21:12 /dev/ad0s6 -> ad0s3+000410a1
lrwxr-xr-x 1 root wheel 14 4 3 21:12 /dev/ad0s7 -> ad0s3+00103bf1
lrwxr-xr-x 1 root wheel 14 4 3 21:12 /dev/ad0s8 -> ad0s3+0017cda1
# gpart show
=> 63 228338775 ad0 MBR (109G)
63 18688257 1 !12 (8.9G)
18688320 16783200 2 freebsd [active] (8.0G)
35471520 192855600 3 !15 (92G)
228327120 11718 - free - (5.7M)
=> 0 16783200 ad0s2 BSD (8.0G)
0 786432 1 freebsd-ufs (384M)
786432 4194304 2 freebsd-swap (2.0G)
4980736 393216 4 freebsd-ufs (192M)
5373952 11409248 5 freebsd-ufs (5.4G)
=> 0 192855600 ad0s3 EBR (92G)
0 16783200 1 !131 (8.0G)
16783200 50243760 266401 !11 (24G)
67026960 31251024 1063921 freebsd (15G)
98277984 94577616 1559969 freebsd (45G)
The only downside is that I'll have to update /etc/fstab to boot correctly
as /dev/ad0s7a is still missing.
--
Thanks,
Tai-hwa Liang
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