Date: Thu, 8 May 2003 12:45:20 +0200 (CEST) From: Lukas Ertl <l.ertl@univie.ac.at> To: Kirk McKusick <mckusick@McKusick.COM> Cc: freebsd-current@freebsd.org Subject: Re: bin/51619 Message-ID: <20030508124346.A42559@pcle2.cc.univie.ac.at> In-Reply-To: <200305072229.h47MTDTh024656@beastie.mckusick.com> References: <200305072229.h47MTDTh024656@beastie.mckusick.com>
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On Wed, 7 May 2003, Kirk McKusick wrote:
> At one time I had the suggested change that you made in bin/51619
> in the FreeBSD-5.0 newfs program. The problem with that change is
> that the bootstrap on some architectures now exceeds 8K which means
> that instead of zeroing an old superblock you destroy the boot code.
> So, I removed the zeroing of the old UFS1 superblock area. A possible
> alternative would be to check for a UFS1 magic number at the old
> location (and also at the 16K first backup location) and zero out
> just those fields if they are found. While it is possible that a
> bootstrap might just have that number at that offset, it is highly
> unlikely.
Hi Kirk,
thanks for clarifying this. Would this patch here be better suited?
---8<---
Index: sbin/newfs/mkfs.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /u/cvs/cvs/src/sbin/newfs/mkfs.c,v
retrieving revision 1.75
diff -u -r1.75 mkfs.c
--- sbin/newfs/mkfs.c=093 May 2003 18:41:58 -0000=091.75
+++ sbin/newfs/mkfs.c=098 May 2003 10:42:15 -0000
@@ -113,6 +113,12 @@
=09quad_t sizepb;
=09int width;
=09char tmpbuf[100];=09/* XXX this will break in about 2,500 years */
+=09union {
+=09=09struct fs fdummy;
+=09=09char cdummy[SBLOCKSIZE];
+=09} dummy;
+#define fsdummy dummy.fdummy
+#define chdummy dummy.cdummy
=09/*
=09 * Our blocks =3D=3D sector size, and the version of UFS we are using i=
s
@@ -479,8 +485,22 @@
=09=09sblock.fs_old_cstotal.cs_nifree =3D sblock.fs_cstotal.cs_nifree;
=09=09sblock.fs_old_cstotal.cs_nffree =3D sblock.fs_cstotal.cs_nffree;
=09}
-=09if (!Nflag)
+=09if (!Nflag) {
+=09=09/*
+=09=09 * Wipe out old UFS1 superblock if necessary.
+=09=09 */
+=09=09if (Oflag !=3D 1) {
+=09=09=09i =3D bread(&disk, SBLOCK_UFS1 / disk.d_bsize, chdummy, SBLOCKSIZ=
E);
+=09=09=09if (i =3D=3D -1)
+=09=09=09=09err(1, "can't bread: %s", disk.d_error);
+
+=09=09=09if (fsdummy.fs_magic =3D=3D FS_UFS1_MAGIC) {
+=09=09=09=09fsdummy.fs_magic =3D 0;
+=09=09=09=09bwrite(&disk, SBLOCK_UFS1 / disk.d_bsize, chdummy, SBLOCKSIZE)=
;
+=09=09=09}
+=09=09}
=09=09sbwrite(&disk, 0);
+=09}
=09for (i =3D 0; i < sblock.fs_cssize; i +=3D sblock.fs_bsize)
=09=09wtfs(fsbtodb(&sblock, sblock.fs_csaddr + numfrags(&sblock, i)),
=09=09=09sblock.fs_cssize - i < sblock.fs_bsize ?
---8<---
regards,
le
--=20
Lukas Ertl eMail: l.ertl@univie.ac.at
UNIX-Systemadministrator Tel.: (+43 1) 4277-14073
Zentraler Informatikdienst (ZID) Fax.: (+43 1) 4277-9140
der Universit=E4t Wien http://mailbox.univie.ac.at/~le/
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