[PATCH blktests v2 1/2] nvme/rc: fix nvme device readiness check after _nvme_connect_subsys

[Daniel Wagner]

On Thu, Aug 17, 2023 at 04:30:20PM +0900, Shin'ichiro Kawasaki wrote:
> The helper function _nvme_connect_subsys() creates a nvme device. It may
> take some time after the function call until the device gets ready for
> I/O. So it is expected that the test cases call _find_nvme_dev() after
> _nvme_connect_subsys() before I/O. _find_nvme_dev() returns the path of
> the created device, and it also waits for uuid and wwid sysfs attributes
> of the created device get ready. This wait works as the wait for the
> device I/O readiness.
> 
> However, this wait by _find_nvme_dev() has two problems. The first
> problem is missing call of _find_nvme_dev(). The test case nvme/047
> calls _nvme_connect_subsys() twice, but _find_nvme_dev() is called only
> for the first _nvme_connect_subsys() call. This causes too early I/O to
> the device with tcp transport [1]. Fix this by moving the wait for the
> device readiness from _find_nvme_dev() to _nvme_connect_subsys(). Also
> add --wait-for option to _nvme_connect_subsys(). It allows to skip the
> wait in _nvmet_passthru_target_connect() which has its own wait for
> device readiness.
> 
> The second problem is wrong paths for the sysfs attributes. The paths
> do not include namespace index, so the check for the attributes always
> fail. Still _find_nvme_dev() does 1 second wait and allows the device
> get ready for I/O in most cases, but this is not intended behavior.
> Fix the paths by adding the namespace index.
> 
> On top of the checks for sysfs attributes, add 'udevadm settle' and a
> check for the created device file. These ensures that the create device
> is ready for I/O.
> 
> [1] https://lore.kernel.org/linux-block/CAHj4cs9GNohGUjohNw93jrr8JGNcRYC-ienAZz+sa7az1RK77w@mail.gmail.com/
> 
> Fixes: c766fccf3aff ("Make the NVMe tests more reliable")
> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki at wdc.com>

Thanks!

Reviewed-by: Daniel Wagner <dwagner at suse.de>