I think I finally figured out where the problem comes from. The "- LABELSECTOR" on line 144 is indeed causing it and should be removed. But it has been added here for a reason: to balance the "+ LABELSECTOR" in the writedisklabel function below, when this part of the code was factorized years ago <http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/macppc/macppc/disksubr.c.diff?r1=1.55;r2=1.56;f=h>
As far as I can tell, LABELSECTOR is an MBR related constant and probably shouldn't have been put in a DPME code in the first place. But in practice, at that time it wasn't a problem since the "hfspartoff" variable was only used (indirectly) by the writedisklabel function. Unfortunately this was no longer the case when bounds were added <http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/macppc/macppc/disksubr.c.diff?r1=1.61;r2=1.63;f=h> So, here is my patch to fix the issue. ==================================================================== diff -u -r1.69 disksubr.c --- disksubr.c 26 Feb 2011 13:07:48 -0000 1.69 +++ disksubr.c 21 May 2011 15:29:35 -0000 @@ -141,7 +141,7 @@ *s = (*s - 'a' + 'A'); if (strcmp(part->pmPartType, PART_TYPE_OPENBSD) == 0) { - hfspartoff = part->pmPyPartStart - LABELSECTOR; + hfspartoff = part->pmPyPartStart; hfspartend = hfspartoff + part->pmPartBlkCnt; if (partoffp) { *partoffp = hfspartoff; @@ -176,7 +176,7 @@ return (0); /* next, dig out disk label */ - bp->b_blkno = hfspartoff + LABELSECTOR; + bp->b_blkno = hfspartoff; bp->b_bcount = lp->d_secsize; bp->b_flags = B_BUSY | B_READ | B_RAW; (*strat)(bp); @@ -201,12 +201,17 @@ bp = geteblk((int)lp->d_secsize); bp->b_dev = dev; - if (readdpmelabel(bp, strat, lp, &partoff, 1) != NULL && - readdoslabel(bp, strat, lp, &partoff, 1) != NULL) - goto done; + if (readdpmelabel(bp, strat, lp, &partoff, 1) != NULL) + { + if (readdoslabel(bp, strat, lp, &partoff, 1) != NULL) + goto done; + else + bp->b_blkno = partoff + LABELSECTOR; + } + else + bp->b_blkno = partoff; /* Read it in, slap the new label in, and write it back out */ - bp->b_blkno = partoff + LABELSECTOR; bp->b_bcount = lp->d_secsize; bp->b_flags = B_BUSY | B_READ | B_RAW; (*strat)(bp); ==================================================================== Here are 2 outputs from the disklabel tool, first before the patch... OpenBSD area: 53706878-58605119; size: 4898241; free: 4898241 ... and after the patch. OpenBSD area: 53706879-58605120; size: 4898241; free: 4898241 I saw that the socppc port has the same piece of code in its "socppc/disksubr.c" file. I can't test on this platform but my best guess is it has the same problem. On 05/08/2011 11:56 PM, Mathieu Olivier wrote: > Hi. > > I recently made some space on my old iBook G4 (1.2 GHz, late 2004 model) > to put a few extra partitions, for a Linux, an OpenBSD 4.9, and a shared > data partition using FAT32. > > During the installation process, I briefly struggled with the disklabel > tool before realizing that my problems came from the fact that it gave > me an incorrect automatic layout to begin with: the root partition was > starting one sector *ahead* of the OpenBSD partition itself. I fixed the > layout manually, but the "boundstart" displayed by disklabel is still > incorrect on my running system, as you can see from those outputs of > pdisk and disklabel respectively: > > > # pdisk wd0 > Edit wd0 - > Command (? for help): p > > Partition map (with 512 byte blocks) on 'wd0' > #: type name length base ( size ) > 1: Apple_partition_map Apple 63 @ 1 > 2: Apple_Bootstrap untitled 1954 @ 39935392 > 3: Apple_HFS Untitled 39673184 @ 262208 ( 18.9G) > 4: Apple_UNIX_SVR2 LinuxRoot 10742188 @ 39937346 ( 5.1G) > 5: Apple_UNIX_SVR2 swap 585938 @ 50679534 (286.1M) > 6: Apple_UNIX_SVR2 Shared 2441407 @ 51265472 ( 1.2G) > 7: Apple_Free Extra 262144 @ 64 (128.0M) > 8: OpenBSD OpenBSD 4898241 @ 53706879 ( 2.3G) > > Device block size=512, Number of Blocks=58605120 (27.9G) > DeviceType=0x0, DeviceId=0x0 > > Command (? for help): q > > # disklabel wd0 > # /dev/rwd0c: > type: ESDI > disk: ESDI/IDE disk > label: TOSHIBA MK3025GA > duid: c2997bcd646b6636 > flags: > bytes/sector: 512 > sectors/track: 63 > tracks/cylinder: 16 > sectors/cylinder: 1008 > cylinders: 58140 > total sectors: 58605120 > boundstart: 53706878 > boundend: 58605119 > drivedata: 0 > > 16 partitions: > # size offset fstype [fsize bsize cpg] > a: 4499968 53706880 4.2BSD 2048 16384 1 # / > b: 398241 58206879 swap > c: 58605120 0 unused > i: 39673184 262208 HFS > j: 2441407 51265472 MSDOS > > > I read some documentation and source files to try to figure out where > this problem comes from, and I stepped across a very suspicious line of > code, in "src/sys/arch/macppc/macppc/disksubr.c" > <http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/macppc/macppc/disksubr.c?annotate=1.69>. > > Line 144: "hfspartoff = part->pmPyPartStart - LABELSECTOR;" > > And, if I'm not mistaken, LABELSECTOR is equal to 1 on MacPPC, and > hfspartoff is used to initialize the boundstart 6 lines later... So > coincidence or real bug ? :) > -- Mathieu Olivier <moliv...@users.sourceforge.net>
