On 4/9/26 6:30 PM, John Garry wrote:
On 09/04/2026 07:37, Nilay Shroff wrote:
You mean a common blktests testcase, right?
For NVMe, that test would:
a. try to remove NVMe ko when we have the delayed removal active
b. ensure that we can queue for no path
I suppose that a common testcase could be possible (with dm mpath), but doesn't
dm have its own testsuite?
Yes, I'd add a blktest for 'queue_if_no_path' feature. But as we know we have
separate test suite for dm under blktests, I'd first target nvme testcase and
then later add another testcase for dm-multipath.
Testing a. is a challenge to be effective, as we would typically not be able to
remove the nvme modules anyway due to many other references.
For b, how about something like the following:
set_conditions() {
_set_nvme_trtype "$@"
}
_delayed_nvme_reconnect_ctrl() {
sleep 2
_nvme_connect_subsys
}
test() {
echo "Running ${TEST_NAME}"
_setup_nvmet
local nvmedev
local ns
local bytes_written
_nvmet_target_setup
_nvme_connect_subsys
# Part a: Ensure writes fail when no path returns
nvmedev=$(_find_nvme_dev "${def_subsysnqn}")
ns=$(_find_nvme_ns "${def_subsys_uuid}")
echo 10 > "/sys/block/"$ns"/delayed_removal_secs"
bytes_written=$(run_xfs_io_pwritev2 /dev/"$ns" 4096)
if [ "$bytes_written" != 4096 ]; then
echo "could not write successfully initially"
fi
sleep 1
_nvme_disconnect_ctrl "${nvmedev}"
sleep 1
ns=$(_find_nvme_ns "${def_subsys_uuid}")
if [[ "${ns}" = "" ]]; then
echo "could not find ns after disconnect"
fi
bytes_written=$(run_xfs_io_pwritev2 /dev/"$ns" 4096)
if [ "$bytes_written" == 4096 ]; then
echo "wrote successfully after disconnect"
fi
sleep 10
ns=$(_find_nvme_ns "${def_subsys_uuid}")
if [[ !"${ns}" = "" ]]; then
echo "found ns after delayed removal"
fi
#echo "now part 2"
# Part b: Ensure writes work for intermittent disconnect
_nvme_connect_subsys
nvmedev=$(_find_nvme_dev "${def_subsysnqn}")
ns=$(_find_nvme_ns "${def_subsys_uuid}")
echo 10 > "/sys/block/"$ns"/delayed_removal_secs"
bytes_written=$(run_xfs_io_pwritev2 /dev/"$ns" 4096)
if [ "$bytes_written" != 4096 ]; then
echo "could not write successfully initially"
fi
sleep 1
_nvme_disconnect_ctrl "${nvmedev}"
sleep 1
ns=$(_find_nvme_ns "${def_subsys_uuid}")
if [[ "${ns}" = "" ]]; then
echo "could not find ns after disconnect"
fi
_delayed_nvme_reconnect_ctrl &
sleep 1
bytes_written=$(run_xfs_io_pwritev2 /dev/"$ns" 4096)
if [ "$bytes_written" != 4096 ]; then
echo "could not write successfully with reconnect"
fi
It seems there may be a race here if we attempt to write to $ns before
the reconnect has completed in _delayed_nvme_reconnect_ctrl.
If the intention is simply to verify that the controller reconnect occurs
within the delayed removal window and test pwrite, then it may be sufficient
to:
- perform the reconnect, and
- then validate the write (pwrite) afterwards.
In that case, we could either:
- run _delayed_nvme_reconnect_ctrl in the foreground, or
- open-code the reconnect directly in the script before issuing the write.
sleep 10
ns=$(_find_nvme_ns "${def_subsys_uuid}")
if [[ "${ns}" = "" ]]; then
echo "could not find ns after delayed reconnect"
fi
# Final tidy-up
echo 0 > /sys/block/"$ns"/delayed_removal_secs
nvmedev=$(_find_nvme_dev "${def_subsysnqn}")
_nvme_disconnect_ctrl "${nvmedev}"
_nvmet_target_cleanup
echo "Test complete"
}
Otherwise overall this looks good to me.
Thanks,
--Nilay
