Messages in this thread | | | Subject | Re: [PATCH v7 08/14] nvmet-core: allow one host per passthru-ctrl | From | Max Gurtovoy <> | Date | Sun, 18 Aug 2019 13:33:47 +0300 |
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On 8/15/2019 7:06 PM, Logan Gunthorpe wrote: > > On 2019-08-15 6:36 a.m., Max Gurtovoy wrote: >> On 8/2/2019 2:45 AM, Logan Gunthorpe wrote: >>> This patch rejects any new connection to the passthru-ctrl if this >>> controller is already connected to a different host. At the time of >>> allocating the controller we check if the subsys associated with >>> the passthru ctrl is already connected to a host and reject it >>> if the hostnqn differs. >> This is a big limitation. >> >> Are we plan to enable many front-end ctrl's to connect to the single >> back-end ctrl in the future ? > Honestly, I don't know that it's really necessary, but the limitation > was requested by Sagi the first time this patch-set was submitted[1] > citing unspecified user troubles. If there's consensus to remove the > restriction I certainly can. > > Logan > > [1] http://lists.infradead.org/pipermail/linux-nvme/2018-April/016588.html
I don't understand why we don't limit a regular ctrl to single access and we do it for the PT ctrl.
I guess the block layer helps to sync between multiple access in parallel but we can do it as well.
Also, let's say you limit the access to this subsystem to 1 user, the bdev is still accessibly for local user and also you can create a different subsystem that will use this device (PT and non-PT ctrl).
Sagi,
can you explain the trouble you meant and how this limitation solve it ?
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