On 7/5/21 3:02 PM, Paolo Bonzini wrote:
On 02/07/21 16:21, Martin Wilck wrote:
SG_IO gives you raw access to the SCSI logic unit, and you get to
keep the pieces if anything goes wrong.
That's a very fragile user space API, on the fringe of being useless
IMO.
Indeed. If SG_IO is for raw access to an ITL nexus, it shouldn't be
supported at all by mpath devices. If on the other hand SG_IO is for
raw access to a LUN, there is no reason for it to not support failover.
Or we look at IO_URING_OP_URING_CMD, to send raw cdbs via io_uring.
And delegate SG_IO to raw access to an ITL nexus.
Doesn't help with existing issues, but should get a clean way forward.
... I think I've even tendered a topic at LSF for this ...
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
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