diff --git a/SOURCES/0001-cache-cow-Fix-data-corruption-in-zero-and-trim-on-un.patch b/SOURCES/0001-cache-cow-Fix-data-corruption-in-zero-and-trim-on-un.patch
index ad8500b..151fc17 100644
--- a/SOURCES/0001-cache-cow-Fix-data-corruption-in-zero-and-trim-on-un.patch
+++ b/SOURCES/0001-cache-cow-Fix-data-corruption-in-zero-and-trim-on-un.patch
@@ -78,5 +78,5 @@ index 51ca64a4..1cfcc4e7 100644
      }
      if (r == -1)
 -- 
-2.18.4
+2.31.1
 
diff --git a/SOURCES/0002-server-CVE-2021-3716-reset-structured-replies-on-sta.patch b/SOURCES/0002-server-CVE-2021-3716-reset-structured-replies-on-sta.patch
index df33105..ce6938e 100644
--- a/SOURCES/0002-server-CVE-2021-3716-reset-structured-replies-on-sta.patch
+++ b/SOURCES/0002-server-CVE-2021-3716-reset-structured-replies-on-sta.patch
@@ -90,5 +90,5 @@ index 0a76a814..b94950e2 100644
            struct handle *h = get_handle (conn, b->i);
            free (h->default_exportname);
 -- 
-2.18.4
+2.31.1
 
diff --git a/SOURCES/0003-server-reset-meta-context-replies-on-starttls.patch b/SOURCES/0003-server-reset-meta-context-replies-on-starttls.patch
index 18213dc..4ab0de0 100644
--- a/SOURCES/0003-server-reset-meta-context-replies-on-starttls.patch
+++ b/SOURCES/0003-server-reset-meta-context-replies-on-starttls.patch
@@ -36,5 +36,5 @@ index b94950e2..eb0f3961 100644
            struct handle *h = get_handle (conn, b->i);
            free (h->default_exportname);
 -- 
-2.18.4
+2.31.1
 
diff --git a/SOURCES/0004-cow-Fix-for-qemu-6.1-which-requires-backing-format.patch b/SOURCES/0004-cow-Fix-for-qemu-6.1-which-requires-backing-format.patch
new file mode 100644
index 0000000..eb7e88e
--- /dev/null
+++ b/SOURCES/0004-cow-Fix-for-qemu-6.1-which-requires-backing-format.patch
@@ -0,0 +1,59 @@
+From 3c2879a38c299b725091cea45329879e3f46fc99 Mon Sep 17 00:00:00 2001
+From: "Richard W.M. Jones" <rjones@redhat.com>
+Date: Tue, 31 Aug 2021 11:23:27 +0100
+Subject: [PATCH] cow: Fix for qemu 6.1 which requires backing format
+
+The diffing example in the manual created a qcow2 file with a backing
+file but did not specify the backing format.  However qemu 6.1 now
+requires this and fails with:
+
+  qemu-img: cow-diff.qcow2: Backing file specified without backing format
+
+or:
+
+  qemu-img: Could not change the backing file to 'cow-base.img': backing format must be specified
+
+Fix the example by adding the -F option to the command line.
+
+Also there was a test of this rebasing sequence which failed, so this
+commit updates the test too.
+
+(cherry picked from commit 618290ef33ce13b75c1a79fea1f1ffb327b5ba07)
+---
+ filters/cow/nbdkit-cow-filter.pod | 4 ++--
+ tests/test-cow.sh                 | 4 ++--
+ 2 files changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/filters/cow/nbdkit-cow-filter.pod b/filters/cow/nbdkit-cow-filter.pod
+index 4d5ae856..510bdd40 100644
+--- a/filters/cow/nbdkit-cow-filter.pod
++++ b/filters/cow/nbdkit-cow-filter.pod
+@@ -101,8 +101,8 @@ At the end, disconnect the client.
+ Run these C<qemu-img> commands to construct a qcow2 file containing
+ the differences:
+ 
+- qemu-img create -f qcow2 -b nbd:localhost diff.qcow2
+- qemu-img rebase -b disk.img diff.qcow2
++ qemu-img create -F raw -b nbd:localhost -f qcow2 diff.qcow2
++ qemu-img rebase -F raw -b disk.img -f qcow2 diff.qcow2
+ 
+ F<diff.qcow2> now contains the differences between the base
+ (F<disk.img>) and the changes stored in nbdkit-cow-filter.  C<nbdkit>
+diff --git a/tests/test-cow.sh b/tests/test-cow.sh
+index 8772afd7..edc4c223 100755
+--- a/tests/test-cow.sh
++++ b/tests/test-cow.sh
+@@ -72,8 +72,8 @@ fi
+ # If we have qemu-img, try the hairy rebase operation documented
+ # in the nbdkit-cow-filter manual.
+ if qemu-img --version >/dev/null 2>&1; then
+-    qemu-img create -f qcow2 -b nbd:unix:$sock cow-diff.qcow2
+-    time qemu-img rebase -b cow-base.img cow-diff.qcow2
++    qemu-img create -F raw -b nbd:unix:$sock -f qcow2 cow-diff.qcow2
++    time qemu-img rebase -F raw -b cow-base.img -f qcow2 cow-diff.qcow2
+     qemu-img info cow-diff.qcow2
+ 
+     # This checks the file we created exists.
+-- 
+2.31.1
+
diff --git a/SPECS/nbdkit.spec b/SPECS/nbdkit.spec
index 8dc63fc..a62641b 100644
--- a/SPECS/nbdkit.spec
+++ b/SPECS/nbdkit.spec
@@ -40,7 +40,7 @@ ExclusiveArch:  x86_64
 
 Name:           nbdkit
 Version:        1.24.0
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        NBD server
 
 License:        BSD
@@ -68,7 +68,7 @@ Source3:        copy-patches.sh
 Patch0001:     0001-cache-cow-Fix-data-corruption-in-zero-and-trim-on-un.patch
 Patch0002:     0002-server-CVE-2021-3716-reset-structured-replies-on-sta.patch
 Patch0003:     0003-server-reset-meta-context-replies-on-starttls.patch
-
+Patch0004:     0004-cow-Fix-for-qemu-6.1-which-requires-backing-format.patch
 
 %if 0%{patches_touch_autotools}
 BuildRequires:  autoconf, automake, libtool
@@ -1238,6 +1238,10 @@ export LIBGUESTFS_TRACE=1
 
 
 %changelog
+* Wed Jan 26 2022 Richard W.M. Jones <rjones@redhat.com> - 1.24.0-4
+- Fix build on RHEL 8.6 with qemu >= 6.1
+  resolves: rhbz#2045945
+
 * Mon Sep 06 2021 Richard W.M. Jones <rjones@redhat.com> - 1.24.0-3
 - Fix CVE-2021-3716 NBD_OPT_STRUCTURED_REPLY injection on STARTTLS
   resolves: rhbz#1994915