[Drbd-dev] DRBD-8: crashes if role is changed to Secondary whilst disk state is Negotiating...

[Drbd-dev] DRBD-8: crashes if role is changed to Secondary whilst disk state is Negotiating...

[Graham, Simon]

The specific crash I saw was due to this code in drbd_set_role; drbd_set_role calls drbd_al_to_on_disk_bm() if the new role is secondary and the disk state is not diskless -- there are transitory states between diskless and attached where this is not valid.

The specific lines of code are:

    if(mdev->state.disk > Diskless && (new_role & Secondary)) {
        drbd_al_to_on_disk_bm(mdev);
    }

and the test should presumably be 'mdev->state.disk > Negotiating' - however, this routine presumably needs to use inc_local() to do this so I would propose the following:

	if ((new_role & Secondary) && inc_local(mdev)) {
		drbd_al_to_on_disk_bm(mdev);

		dec_local(mdev);
	}

Simon

Re: [Drbd-dev] DRBD-8: crashes if role is changed to Secondary whilst disk state is Negotiating...

[Philipp Reisner]

Am Sonntag, 24. September 2006 17:35 schrieb Graham, Simon:
> The specific crash I saw was due to this code in drbd_set_role;
> drbd_set_role calls drbd_al_to_on_disk_bm() if the new role is secondary
> and the disk state is not diskless -- there are transitory states between
> diskless and attached where this is not valid.
>
> The specific lines of code are:
>
>     if(mdev->state.disk > Diskless && (new_role & Secondary)) {
>         drbd_al_to_on_disk_bm(mdev);
>     }
>
> and the test should presumably be 'mdev->state.disk > Negotiating' -
> however, this routine presumably needs to use inc_local() to do this so I
> would propose the following:
>
> 	if ((new_role & Secondary) && inc_local(mdev)) {
> 		drbd_al_to_on_disk_bm(mdev);
>
> 		dec_local(mdev);
> 	}
>

Right.

-Phil
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