From 7ba9e7322e5828686fee9e71d7ffa17fe406c28a Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Tue, 29 Apr 2025 12:47:00 +0100
Subject: [PATCH] input: Add undocumented -io vddk-noextents=true option

This turns on the noextents filter, so that the slow VDDK API
QueryAllocatedBlocks will never be called.  This is just so we can
test in production if this is effective or not.

(cherry picked from commit 191b8cf418076ae3766b134ffa96eee048c7eb9d)
---
 input/input_vddk.ml   | 8 +++++++-
 input/nbdkit_vddk.ml  | 8 +++-----
 input/nbdkit_vddk.mli | 1 +
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/input/input_vddk.ml b/input/input_vddk.ml
index 6444ce18..2edd7294 100644
--- a/input/input_vddk.ml
+++ b/input/input_vddk.ml
@@ -52,6 +52,7 @@ All other settings are optional:
   -io vddk-cookie=COOKIE       VDDK cookie
   -io vddk-libdir=LIBDIR       VDDK library parent directory
   -io vddk-nfchostport=PORT    VDDK nfchostport
+  -io vddk-noextents=true      Avoid slow VDDK QueryAllocatedBlocks API
   -io vddk-port=PORT           VDDK port
   -io vddk-snapshot=SNAPSHOT-MOREF
                                VDDK snapshot moref
@@ -71,6 +72,7 @@ information on these settings.
         "cookie";
         "libdir";
         "nfchostport";
+        "noextents";
         "port";
         "snapshot";
         "thumbprint";
@@ -173,6 +175,9 @@ information on these settings.
       try Some (List.assoc "libdir" io_options) with Not_found -> None in
     let nfchostport =
       try Some (List.assoc "nfchostport" io_options) with Not_found -> None in
+    let noextents =
+      try bool_of_string (List.assoc "noextents" io_options)
+      with Not_found -> false in
     let port =
       try Some (List.assoc "port" io_options) with Not_found -> None in
     let snapshot =
@@ -204,7 +209,8 @@ information on these settings.
              Nbdkit_vddk.create_vddk ?bandwidth:options.bandwidth
                ?config ?cookie ~cor
                ?libdir ~moref
-               ?nfchostport ?password_file:options.input_password ?port
+               ?nfchostport ~noextents
+               ?password_file:options.input_password ?port
                ~server ?snapshot ~thumbprint ?transports ?user
                path in
            let _, pid = Nbdkit.run_unix socket nbdkit in
diff --git a/input/nbdkit_vddk.ml b/input/nbdkit_vddk.ml
index 3ba00d55..5c23efd1 100644
--- a/input/nbdkit_vddk.ml
+++ b/input/nbdkit_vddk.ml
@@ -51,7 +51,7 @@ let libNN = sprintf "lib%d" Sys.word_size
 
 (* Create an nbdkit module specialized for reading from VDDK sources. *)
 let create_vddk ?bandwidth ?config ?cookie ?cor ?libdir ~moref
-                ?nfchostport ?password_file ?port
+                ?nfchostport ~noextents ?password_file ?port
                 ~server ?snapshot ~thumbprint ?transports ?user path =
   if not (Nbdkit.is_installed ()) then
     error (f_"nbdkit is not installed or not working");
@@ -166,11 +166,9 @@ See also the virt-v2v-input-vmware(1) manual.") libNN
    *
    * If used, this filter should be close to the plugin and MUST
    * be below the COW filter.
-   *
-   * XXX Add some kind of debugging flag so we can test how this
-   * works in production.
    *)
-  (*Nbdkit.add_filter_if_available cmd "noextents";*)
+  if noextents then
+    Nbdkit.add_filter_if_available cmd "noextents";
 
   (* Split very large requests to avoid out of memory errors on the
    * server.  Since we're using this filter, also add minblock=512
diff --git a/input/nbdkit_vddk.mli b/input/nbdkit_vddk.mli
index 2345e6e2..ef2082db 100644
--- a/input/nbdkit_vddk.mli
+++ b/input/nbdkit_vddk.mli
@@ -25,6 +25,7 @@ val create_vddk : ?bandwidth:Types.bandwidth ->
                   ?libdir:string ->
                   moref:string ->
                   ?nfchostport:string ->
+                  noextents:bool ->
                   ?password_file:string ->
                   ?port:string ->
                   server:string ->