Pixel writes:
> Jeff Sheinberg <[EMAIL PROTECTED]> writes:
>
> > When the grub shell modifies the MBR for the `hide' or
> > `unhide' command it does not issue a `BLKRRPART ioctl()',
> > unlike fdisk which does issue `BLKRRPART ioctl()' when, eg,
> > only the partition type is modified.
> >
> > The `BLKRRPART ioctl()' should be issued by the grub shell in
> > this case, since the kernel's view of the partition tables
> > may need to be changed, and the kernel needs to be notified
> > of this.
>
> ?? the kernel doesn't give a damn about the partition types[1],
^^^^^^^^^^^^^^^^^^^
> even less about the hideness of a partition!
>
> [1] in fact it does care, but only to know if it is a
> ``strange'' partition (extended parts, remapped one (like
> 0x55))
>
[snip]
The following typescript shows that the kernel's view of the
partition tables does in fact change, just by changing the
partition type,
30 jsroot ~ # uname -sr
Linux 2.2.13
31 jsroot ~ # cat /proc/partitions | grep sdb
8 16 4233600 sdb
8 17 1 sdb1
8 18 827347 sdb2
8 19 819315 sdb3
8 20 819315 sdb4
8 21 128457 sdb5
8 22 819283 sdb6
8 23 819283 sdb7
8 24 40960 sdb8
8 25 196608 sdb9
8 26 589779 sdb10
32 jsroot ~ # fdisk /dev/sdb
Command (m for help): p
Disk /dev/sdb: 255 heads, 63 sectors, 527 cylinders
Units = cylinders of 16065 * 512 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 1 220 1767118+ 5 Extended
/dev/sdb2 221 323 827347+ a5 BSD/386
/dev/sdb3 324 425 819315 83 Linux
/dev/sdb4 426 527 819315 b9 Unknown
/dev/sdb5 1 16 128457 82 Linux swap
/dev/sdb6 17 118 819283+ 83 Linux
/dev/sdb7 119 220 819283+ 83 Linux
Command (m for help): t 2
Partition number (1-7): 2
Hex code (type L to list codes): b5
Changed system type of partition 2 to b5 (Unknown)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
information.
Syncing disks.
33 jsroot ~ # cat /proc/partitions | grep sdb
8 16 4233600 sdb
8 17 1 sdb1
8 18 827347 sdb2
8 19 819315 sdb3
8 20 819315 sdb4
8 21 128457 sdb5
8 22 819283 sdb6
8 23 819283 sdb7
34 jsroot ~ #
There were 10 partitions on /dev/sdb before I changed the
partition type of /dev/sdb2 from `a5' BSD/386 to `b5' Unknown, ie,
hidden. After hiding /dev/sdb2, there are now only 7 partitions.
--
Jeff Sheinberg <[EMAIL PROTECTED]>
