diff --git a/0001-lib-Autodetect-backing-format-for-qemu-img-create-b.patch b/0001-lib-Autodetect-backing-format-for-qemu-img-create-b.patch
new file mode 100644
index 0000000..9a2250f
--- /dev/null
+++ b/0001-lib-Autodetect-backing-format-for-qemu-img-create-b.patch
@@ -0,0 +1,48 @@
+From 45de287447bb18d59749fbfc1ec5072413090109 Mon Sep 17 00:00:00 2001
+From: "Richard W.M. Jones" <rjones@redhat.com>
+Date: Tue, 31 Aug 2021 08:27:15 +0100
+Subject: [PATCH] lib: Autodetect backing format for qemu-img create -b
+
+qemu 6.1 has decided to change qemu-img create so that a backing
+format (-F) is required if a backing file (-b) is specified.  Since we
+don't want to change the libguestfs API to force callers to specify
+this because that would be an API break, autodetect it.
+
+This is similar to commit c8c181e8d9 ("launch: libvirt: Autodetect
+backing format for readonly drive overlays").
+
+Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1998820
+---
+ lib/create.c | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+
+diff --git a/lib/create.c b/lib/create.c
+index 44a7df25f..75a4d3a28 100644
+--- a/lib/create.c
++++ b/lib/create.c
+@@ -255,6 +255,7 @@ disk_create_qcow2 (guestfs_h *g, const char *filename, int64_t size,
+                    const struct guestfs_disk_create_argv *optargs)
+ {
+   const char *backingformat = NULL;
++  CLEANUP_FREE char *backingformat_free = NULL;
+   const char *preallocation = NULL;
+   const char *compat = NULL;
+   int clustersize = -1;
+@@ -270,6 +271,14 @@ disk_create_qcow2 (guestfs_h *g, const char *filename, int64_t size,
+       return -1;
+     }
+   }
++  else if (backingfile) {
++    /* Since qemu 6.1, qemu-img create has requires a backing format (-F)
++     * parameter if backing file (-b) is used (RHBZ#1998820).
++     */
++    backingformat = backingformat_free = guestfs_disk_format (g, backingfile);
++    if (!backingformat)
++      return -1;
++  }
+   if (optargs->bitmask & GUESTFS_DISK_CREATE_PREALLOCATION_BITMASK) {
+     if (STREQ (optargs->preallocation, "off") ||
+         STREQ (optargs->preallocation, "sparse"))
+-- 
+2.32.0
+
diff --git a/libguestfs.spec b/libguestfs.spec
index e5a2bfe..0151c70 100644
--- a/libguestfs.spec
+++ b/libguestfs.spec
@@ -57,7 +57,7 @@ Summary:       Access and modify virtual machine disk images
 Name:          libguestfs
 Epoch:         1
 Version:       1.45.6
-Release:       11%{?dist}
+Release:       12%{?dist}
 License:       LGPLv2+
 
 # Build only for architectures that have a kernel
@@ -91,6 +91,10 @@ Source7:       libguestfs.keyring
 # Maintainer script which helps with handling patches.
 Source8:       copy-patches.sh
 
+# Upstream patch to work with qemu 6.1
+# https://bugzilla.redhat.com/show_bug.cgi?id=1998820
+Patch1:        0001-lib-Autodetect-backing-format-for-qemu-img-create-b.patch
+
 # Downstream (RHEL-only) patches.
 %if 0%{?rhel}
 Patch9001:     0001-RHEL-Remove-libguestfs-live-RHBZ-798980.patch
@@ -1139,6 +1143,9 @@ rm ocaml/html/.gitignore
 
 
 %changelog
+* Tue Aug 31 2021 Richard W.M. Jones <rjones@redhat.com> - 1:1.45.6-12
+- Upstream patch to work with qemu 6.1 (RHBZ#1998820)
+
 * Fri Aug 06 2021 Richard W.M. Jones <rjones@redhat.com> - 1:1.45.6-11
 - Fix license files.
 - Move appliance to separate subpackage (RHBZ#1989514).