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Re: ataraid(4) and VOP_OPENing the same block device

On Aug,Tuesday 26 2008, at 7:18 PM, Juan Romero Pardines wrote:

2008/8/26 Adam Hamsik <>:

I think that it is not possible to VOP_OPEN block device more than once,
but you can open raw devices  as many times as you want.

In my device-mapper driver I created
struct pdev {
      struct vnode pdev_vnode;
      . . .

Which is in SLIST shared between all dm devices in system. When dm device is created I VOP_OPEN selected disk device and add it's vnode to pdev SLIST. When another dm device with same disk is created I search SLIST list for
return it. You can look at this code at haad-dm branch in

You probably need to do the same in ld0, or you can use device- mapper to do
for you and only write own target.

Thanks for the suggestion, but this won't work with the ld(4) driver where
it uses the d_strategy method of bdevsw extensively.

You mean ldstrategy in ld(4) driver here ?

I should note that just after I encountered this problem, my next step was to use the character device... but I noticed that it doesn't have the d_strategy

read and write calls on raw devices are transformed to strategy call by physio routine.



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