From e12604349587b67b3b4c3d0b7b1779999460a93d Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Fri, 19 Jun 2020 13:43:47 +0100
Subject: [PATCH] v2v: Disable readahead for VMware curl sources too
 (RHBZ#1848862).

This appears to be the cause of timeouts during the conversion step
where VMware VCenter server's Tomcat HTTPS server stops responding to
requests (or rather, responds only with 503 errors).  The server later
recovers and in fact because of the retry filter the conversion
usually succeeds, but I found that we can avoid the problem by
disabling readahead.

(cherry picked from commit 9f4940068022d4e7abdfea6617b73a2b206f19aa)
---
 v2v/nbdkit_sources.ml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/v2v/nbdkit_sources.ml b/v2v/nbdkit_sources.ml
index f5e91911..7c177e35 100644
--- a/v2v/nbdkit_sources.ml
+++ b/v2v/nbdkit_sources.ml
@@ -99,12 +99,12 @@ let common_create ?bandwidth ?extra_debug ?extra_env password
 
   (* Adding the readahead filter is always a win for our access
    * patterns.  If it doesn't exist don't worry.  However it
-   * breaks VMware servers (RHBZ#1832805).
+   * breaks VMware servers (RHBZ#1832805, RHBZ#1848862).
    *)
   let cmd =
-    if plugin_name <> "vddk" then
-      Nbdkit.add_filter_if_available cmd "readahead"
-    else cmd in
+    match plugin_name with
+    | "vddk" | "curl" -> cmd
+    | _ -> Nbdkit.add_filter_if_available cmd "readahead" in
 
   (* Caching extents speeds up qemu-img, especially its consecutive
    * block_status requests with req_one=1.