diff --git a/0001-tests-Provide-full-path-to-Unix-domain-sockets.patch b/0001-tests-Provide-full-path-to-Unix-domain-sockets.patch
index 1180deb..2d41fee 100644
--- a/0001-tests-Provide-full-path-to-Unix-domain-sockets.patch
+++ b/0001-tests-Provide-full-path-to-Unix-domain-sockets.patch
@@ -1,9 +1,9 @@
-From 06adc3dbfa162074a3cf20c58b8949f447b37ae5 Mon Sep 17 00:00:00 2001
+From 974f6aba15d71984b5f05dc8b5f10bb7a5cec082 Mon Sep 17 00:00:00 2001
 From: "Richard W.M. Jones" <rjones@redhat.com>
 Date: Wed, 6 Jun 2018 19:29:35 +0100
-Subject: [PATCH] tests: Provide full path to Unix domain sockets.
+Subject: [PATCH 1/2] tests: Provide full path to Unix domain sockets.
 
-Maybe a bug in libvirt?
+See also this thread:
 https://www.redhat.com/archives/libvir-list/2018-June/msg00490.html
 ---
  tests/test-cache.sh | 3 ++-
@@ -11,7 +11,7 @@ https://www.redhat.com/archives/libvir-list/2018-June/msg00490.html
  2 files changed, 4 insertions(+), 2 deletions(-)
 
 diff --git a/tests/test-cache.sh b/tests/test-cache.sh
-index e5e9e82..ac99ce2 100755
+index e5e9e82..c46e7be 100755
 --- a/tests/test-cache.sh
 +++ b/tests/test-cache.sh
 @@ -32,6 +32,7 @@
@@ -27,12 +27,12 @@ index e5e9e82..ac99ce2 100755
  
  # Open the overlay and perform some operations.
 -guestfish --format=raw -a 'nbd://?socket=cache.sock' <<'EOF'
-+guestfish --format=raw -a "nbd://?socket=`pwd`/cache.sock" <<'EOF'
++guestfish --format=raw -a "nbd://?socket=$PWD/cache.sock" <<'EOF'
    run
    part-disk /dev/sda gpt
    mkfs ext4 /dev/sda1
 diff --git a/tests/test-cow.sh b/tests/test-cow.sh
-index 443ba38..4b798c8 100755
+index 443ba38..01d2d04 100755
 --- a/tests/test-cow.sh
 +++ b/tests/test-cow.sh
 @@ -32,6 +32,7 @@
@@ -48,7 +48,7 @@ index 443ba38..4b798c8 100755
  
  # Write some data into the overlay.
 -guestfish --format=raw -a 'nbd://?socket=cow.sock' -m /dev/sda1 <<EOF
-+guestfish --format=raw -a "nbd://?socket=`pwd`/cow.sock" -m /dev/sda1 <<EOF
++guestfish --format=raw -a "nbd://?socket=$PWD/cow.sock" -m /dev/sda1 <<EOF
    fill-dir / 10000
    fill-pattern "abcde" 5M /large
    write /hello "hello, world"
diff --git a/0002-tests-xz-Use-16M-block-size-when-preparing-disk-for-.patch b/0002-tests-xz-Use-16M-block-size-when-preparing-disk-for-.patch
new file mode 100644
index 0000000..617b2b4
--- /dev/null
+++ b/0002-tests-xz-Use-16M-block-size-when-preparing-disk-for-.patch
@@ -0,0 +1,52 @@
+From 013a3a96a102d1b1481a08b6d37bdf958d123985 Mon Sep 17 00:00:00 2001
+From: "Richard W.M. Jones" <rjones@redhat.com>
+Date: Wed, 6 Jun 2018 20:06:39 +0100
+Subject: [PATCH 2/2] tests: xz: Use 16M block size when preparing disk for xz
+ plugin test.
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+In a recent commit guestfish changed the default size for disk images
+prepared using the -N parameter from 100M to 1G:
+
+  https://github.com/libguestfs/libguestfs/commit/adc23829e4b128562c2c29d984654528bd259644
+
+For the xz plugin test we prepared a disk image using guestfish and
+then xz-compressing the output, but we did not take our own advice and
+use the --block-size parameter to limit the xz block size.  Because of
+the increased size of the disk as a whole, this pushed the block size
+beyond the limit that the xz plugin can handle, and the test would
+fail with:
+
+  nbdkit: error: /var/tmp/nbdkit-1.3.1/tests/disk.xz: xz file largest block is bigger than maxblock
+  Either recompress the xz file with smaller blocks (see nbdkit-xz-plugin(1))
+  or make maxblock parameter bigger.
+  maxblock = 536870912 (bytes)
+  largest block in xz file = 1073741824 (bytes)
+
+Simple fix by adding the --block-size parameter.
+
+Note that to see the effect of this change you will need to ‘make
+maintainer-clean’ or remove the files ‘tests/disk’ and ‘tests/disk.xz’
+by hand.
+---
+ tests/Makefile.am | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/tests/Makefile.am b/tests/Makefile.am
+index 4582120..0cc2618 100644
+--- a/tests/Makefile.am
++++ b/tests/Makefile.am
+@@ -328,7 +328,7 @@ test_xz_LDADD = libtest.la $(LIBGUESTFS_LIBS)
+ 
+ disk.xz: disk
+ 	rm -f $@
+-	xz --best -c disk > $@
++	xz --best --block-size=16777216 -c disk > $@
+ 
+ endif HAVE_GUESTFISH
+ endif HAVE_LIBLZMA
+-- 
+2.16.2
+
diff --git a/nbdkit.spec b/nbdkit.spec
index 0dc110f..a8472b9 100644
--- a/nbdkit.spec
+++ b/nbdkit.spec
@@ -26,7 +26,9 @@ URL:            https://github.com/libguestfs/nbdkit
 
 Source0:        http://libguestfs.org/download/nbdkit/%{name}-%{version}.tar.gz
 
+# Upstream patches to fix the tests.
 Patch1:         0001-tests-Provide-full-path-to-Unix-domain-sockets.patch
+Patch2:         0002-tests-xz-Use-16M-block-size-when-preparing-disk-for-.patch
 
 %if 0%{?rhel} == 7
 # On RHEL 7, nothing in the virt stack is shipped on aarch64 and
@@ -646,6 +648,7 @@ popd
 * Wed Jun  6 2018 Richard W.M. Jones <rjones@redhat.com> - 1.3.1-1
 - New upstream version 1.3.1.
 - Add patch to work around libvirt problem with relative socket paths.
+- Add patch to fix the xz plugin test with recent guestfish.
 
 * Fri Apr  6 2018 Richard W.M. Jones <rjones@redhat.com> - 1.3.0-1
 - Move to development branch version 1.3.0.