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[[!meta title="BLKRRPART IOCTL"]]

[[!tag open_issue_glibc open_issue_hurd open_issue_gnumach]]

Just like in other Unix systems one can, for example, use `fdisk` or `parted`
to manage hard disks' partition tables.  After doing changes to a disk's
partition table, the kernel has to be instructed to reinitialize its internal
data structures: where does a partition begin, where does it end, etc.

With `fdisk` and friends this is done on Linux with the `BLKRRPART` IOCTL,
which is used to tell the kernel to reread the disk's partition table.

`parted` also uses this interface on Linux, but for GNU Hurd, the corresponding
function, `libparted/arch/gnu.c (gnu_disk_commit)`, doesn't do anything at all.
The infrastructure in [[GNU_Mach|microkernel/mach/gnumach]] is already there,
`linux/src/drivers/block/ide.c (ide_ioctl) <BLKRRPART>` and
`linux/src/drivers/scsi/sd_ioctl.c (sd_ioctl) <BLKRRPART>`, but the IOCTL needs
to be routed from `libparted` through [[glibc]]'s Hurd IOCTL interface, through
Hurd's [[hurd/libstore]], to [[GNU_Mach|microkernel/mach/gnumach]].

This is not a huge project, and actually one that is suitable for someone who
wants to start with hacking the system.