doc: add qemu-storage-daemon link

Signed-off-by: Ming Lei <[email protected]>

doc/external_links.rst

@@ -6,14 +6,22 @@ External ublk documents
 Tech
 ====
 
+2023
+----
+
+`qemu-storage-daemon ublk export - <https://gitlab.com/amarjargal.gundjalam/qemu/-/blob/ublk_test1/block/export/ublk.c>`
+
+`ublk Target - SPDK <https://spdk.io/doc/ublk.html>`
+
+2022
+----
+
 `LWN: An io_uring-based user-space block driver <https://lwn.net/Articles/903855/>`
 
 `LWN: Crash recovery for user-space block drivers <https://lwn.net/Articles/906097/>`
 
 `An NBD block device written using Linux ublk (user block device) <https://rwmj.wordpress.com/2022/08/25/an-nbd-block-device-written-using-linux-ublk-user-block-device/>`
 
-`ublk Target - SPDK <https://spdk.io/doc/ublk.html>`
-
 `Hacker News: An io_uring-based user-space block driver (lwn.net) <https://news.ycombinator.com/item?id=32508659>`