engines/xnvme: fix fdp support for userspace drivers

The xNVMe backend supports FDP commands for userspace drivers
such as SPDK. Enable support in the xnvme ioengine.
Update the xnvme fdp example file accordingly.

Signed-off-by: Ankit Kumar <ankit.kumar@samsung.com>
Link: https://lore.kernel.org/r/20231102135928.195372-1-ankit.kumar@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

engines/xnvme.c

@@ -964,7 +964,7 @@ static int xnvme_fioe_fetch_ruhs(struct thread_data *td, struct fio_file *f,
 	uint32_t nsid;
 	int err = 0, err_lock;
 
-	if (f->filetype != FIO_TYPE_CHAR) {
+	if (f->filetype != FIO_TYPE_CHAR && f->filetype != FIO_TYPE_FILE) {
 		log_err("ioeng->fdp_ruhs(): ignoring filetype: %d\n", f->filetype);
 		return -EINVAL;
 	}

examples/xnvme-fdp.fio

@@ -16,6 +16,26 @@
 ;   --xnvme_sync=nvme \
 ;   --filename=/dev/ng0n1
 ;
+; # Use the xNVMe io-engine engine with SPDK backend, note that you have to set the Namespace-id
+; fio examples/xnvme-fdp.fio \
+;   --section=default \
+;   --ioengine=xnvme \
+;   --xnvme_dev_nsid=1 \
+;   --filename=0000\\:01\\:00.0
+;
+; NOTE: The URI encoded in the filename above, the ":" must be escaped.
+;
+; On the command-line using two "\\":
+;
+; --filename=0000\\:01\\:00.0
+;
+; Within a fio-script using a single "\":
+;
+; filename=0000\:01\:00.0
+;
+; NOTE: If you want to override the default bs, iodepth, and workload, then
+; invoke it as:
+;
 ; FIO_BS="512" FIO_RW="read" FIO_IODEPTH=16 fio examples/xnvme-fdp.fio \
 ;   --section=override --ioengine=xnvme --xnvme_sync=nvme --filename=/dev/ng0n1
 ;