When a bdev is being unregistered, after all
channels have been closed, the bdev layer calls
the module's destruct callback for the bdev before
calling the bdev unregister callback.
For the rbd module, the destruct callback is
bdev_rbd_destruct. This callback unregisters the
rbd io_device which is an asynchronous operation.
We need to return >0 from bdev_rbd_destruct to
inform the bdev layer that this is an asynchronous
operation, so that it does not immediately call
the bdev unregister callback. Once the rbd io_device
is unregistered, we can call spdk_bdev_destruct_done()
which will trigger the bdev layer to finally call
the bdev unregister callback.
Without this fix, deleting an rbd bdev would
complete before the backing cluster reference
had been released. This meant that even
if you had deleted all rbd bdevs, there might still
be cluster references in place for a short period of
time. It's better to wait to complete the delete
operation until the cluster reference has been
released to avoid this issue (which this patch
now does).
Fixes issue #2069.
Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: I8ac156c89d3e235a95ef196308cc349e6078bfd7
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/9115
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Ziye Yang <ziye.yang@intel.com>
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