Messages in this thread | | | Date | Mon, 22 Dec 2008 21:24:33 +0000 | From | Alasdair G Kergon <> | Subject | Re: [dm-devel] Re: Device mapper support for more than one target ? |
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On Tue, Dec 23, 2008 at 12:24:49AM +0530, Sandeep K Sinha wrote: > On Tue, Dec 23, 2008 at 12:20 AM, Alasdair G Kergon <agk@redhat.com> wrote: > > On Mon, Dec 22, 2008 at 10:52:08PM +0530, Sandeep K Sinha wrote: > > Because whether or not it makes sense to send any specific ioctl to more > > than one target in parallel depends on what that ioctl does. When we > > added that code we said that we could add hard-coding for specific > > ioctls if the need arose, but so far it hasn't. > No, the philosophy should be that we send the ioctl's to the mapped > device and not to the targets underlying that mapped-device.
That's not what the current implementation was for, viz. passing scsi ioctls through dm multipath devices.
> And doing so, I should be able to access the complete map that belongs > to that mapped device. If I implement an ioctl of my own and try to > serve it, the problem would be that it would never allow me to serve > it if has more than one target.
As I said above, if the need arises we can have a whitelist mechanism for ioctls to be handled differently, but the only safe default behaviour is the one that has been implemented.
Alasdair -- agk@redhat.com
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