Re: Re: BLKRRPART ioctl

    [e-mail] (Russell Coker) writes:
    > I have been looking into the issue of fdisk requiring a reboot.
    > It seems that if the device has a usage count >1 (the operation of
    > fdisk counts as 1 for this apparently) then it will not re-read the
    > partition table.

    I've been caught out by this before.  All I've wanted to do was modify
    the partition table to partition some space that I'd previously left
    unallocated.

    I noticed that at some point, the ioctls BLKPG_{ADD,DEL}_PARTITION were
    added (look at drivers/block/blkpg.c).  It looks as if fdisk (et al)
    would be able to inform the kernel of changes to the partition table
    piecemeal, and thus avoid the problem of requiring a reboot if any
    partition on a disk were in use.

    The comment has "aeb" in it, so perhaps Andries Brouwer could comment?

Yes, indeed.
It is now possible to add and remove partitions on the fly.
In particular, there is no longer a need for the kernel
to recognize all possible partition types.
It is enough if it understands the partitioning of the boot device.
(And, using initrd, even this requirement can be relaxed.)

Andries