Re: Devd event from GEOM?

From: Robert Watson (rwatson_at_FreeBSD.org)
Date: 01/30/05

  • Next message: Niclas Zeising: "[PATCH] Kernel module compile faliure in mcd" 
    Date: Sun, 30 Jan 2005 15:37:03 +0000 (GMT)
To: Poul-Henning Kamp <phk@phk.freebsd.dk>

    On Sun, 30 Jan 2005, Poul-Henning Kamp wrote:

    > In message <20050130161323.5e25414e@Magellan.Leidinger.net>, Alexander Leidinger writes:
    >
    > >Let's take a CD for example, when it arrives the auto-mounter mounts it.
    > >Fine, but the CD is locked then. What do we do when we want to remove
    > >the CD? Or another example, an USB stick. The hardware isn't locked, but
    > >when we just remove it, we're calling for a kernel panic.
    >
    > Now that local-storage filesystems are GEOM users, we can actually get
    > the "orphan" event from GEOM communicated to the filesystem which can
    > then take proper evasive action. No filesystem has implemented this yet.

    I think tolerance of hard removal faults will always be a tricky issue --
    we can clearly handle it better than we do today. The user losing data is
    fine: if you don't want to lose data, you have to arrange for a clean
    unmount. However, today's panic is a bit extreme.

    The good news is that soft eject is a lot easier to handle, as it's more
    of a question of signalling and management than hard technical issues in
    how to tear down state at a bad moment in the kernel.

    Robert N M Watson

    _______________________________________________
    freebsd-current@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-current
    To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"

  • Next message: Niclas Zeising: "[PATCH] Kernel module compile faliure in mcd"