Testing with Loopback I found that, after a Loopback LUN has executed a
TMR, I can no longer unlink the LUN. The rm command hangs in
transport_clear_lun_ref() at wait_for_completion(&lun->lun_shutdown_comp)
The reason is, that transport_lun_remove_cmd() is not called at the end of
target_tmr_work().
It seems, that in other fabrics this call happens implicitly when the
fabric drivers call transport_generic_free_cmd() during their
->queue_tm_rsp().
Unfortunately Loopback seems to not comply to the common way
of calling transport_generic_free_cmd() from ->queue_*().
Instead it calls transport_generic_free_cmd() from its
->check_stop_free() only.
But the ->check_stop_free() is called by
transport_cmd_check_stop_to_fabric() after it has reset the se_cmd->se_lun
pointer. Therefore the following transport_generic_free_cmd() skips the
transport_lun_remove_cmd().
So this patch re-adds the transport_lun_remove_cmd() at the end of
target_tmr_work(), which was removed during commit 2c9fa49e10 ("scsi:
target/core: Make ABORT and LUN RESET handling synchronous").
For fabrics using transport_generic_free_cmd() in the usual way the double
call to transport_lun_remove_cmd() doesn't harm, as
transport_lun_remove_cmd() checks for this situation and does not release
lun_ref twice.
Link: https://lore.kernel.org/r/20200513153443.3554-1-bstroesser@ts.fujitsu.com
Fixes: 2c9fa49e10 ("scsi: target/core: Make ABORT and LUN RESET handling synchronous")
Cc: stable@vger.kernel.org
Tested-by: Bryant G. Ly <bryangly@gmail.com>
Reviewed-by: Bart van Assche <bvanassche@acm.org>
Signed-off-by: Bodo Stroesser <bstroesser@ts.fujitsu.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
f2e6b75f6e