[Libguestfs] [PATCH 2/5] v2v/lib/util.ml: Get disk allocation from input

[Nir Soffer]

After finalizing the transfer, virt-v2v try to connect to the output
socket and query disk allocation. This may work for some outputs
supporting block status, but for rhv_upload output this cannot work for
2 reasons:
- The rhv-upload-plugin does not support extents
- The transfer was finalized before this call, so the plugin lost access
  to the image.

Here is an example failure log:

[  74.2] Creating output metadata
python3 '/tmp/v2v.WMq8Tk/rhv-upload-finalize.py' '/tmp/v2v.WMq8Tk/params6.json'
finalizing transfer b03fe3ba-a4ff-4634-a0a0-10b3daba3cc2
...
transfer b03fe3ba-a4ff-4634-a0a0-10b3daba3cc2 finalized in 2.118 seconds
...
nbdkit: debug: accepted connection
...
nbdkit: python[4]: debug: python: close
virt-v2v: error: exception: NBD.Error("nbd_block_status: request out of
bounds: Invalid argument", 22)

Fix by using the input socket.
---
 lib/utils.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/utils.ml b/lib/utils.ml
index d6861d08..f6c85543 100644
--- a/lib/utils.ml
+++ b/lib/utils.ml
@@ -171,21 +171,21 @@ let with_nbd_connect_unix ~socket ~meta_contexts ~f =
     ~f:(fun () ->
           List.iter (NBD.add_meta_context nbd) meta_contexts;
           NBD.connect_unix nbd socket;
           protect
             ~f:(fun () -> f nbd)
             ~finally:(fun () -> NBD.shutdown nbd)
        )
     ~finally:(fun () -> NBD.close nbd)
 
 let get_disk_allocated ~dir ~disknr =
-  let socket = sprintf "%s/out%d" dir disknr
+  let socket = sprintf "%s/in%d" dir disknr
   and alloc_ctx = "base:allocation" in
   with_nbd_connect_unix ~socket ~meta_contexts:[alloc_ctx]
     ~f:(fun nbd ->
          if NBD.can_meta_context nbd alloc_ctx then (
            (* Get the list of extents, using a 2GiB chunk size as hint. *)
            let size = NBD.get_size nbd
            and allocated = ref 0_L
            and fetch_offset = ref 0_L in
            while !fetch_offset < size do
              let remaining = size -^ !fetch_offset in
-- 
2.33.1