Test btrfs in CI

.cirrus.yml

@@ -78,6 +78,8 @@ fedora_testing_task: &fedora_testing
             TEST_DRIVER: "fuse-overlay"
         - env:
             TEST_DRIVER: "fuse-overlay-whiteout"
+        - env:
+            TEST_DRIVER: "btrfs"
 
     # Separate scripts for separate outputs, makes debugging easier.
     setup_script: '${CIRRUS_WORKING_DIR}/${SCRIPT_BASE}/setup.sh |& ${_TIMESTAMP}'
@@ -90,6 +92,7 @@ fedora_testing_task: &fedora_testing
         journal_log_script: '${_JOURNALCMD} || true'
 
 
+# aufs was dropped between 20.04 and 22.04, can't test it
 ubuntu_testing_task: &ubuntu_testing
     <<: *fedora_testing
     alias: ubuntu_testing
@@ -102,6 +105,12 @@ ubuntu_testing_task: &ubuntu_testing
             TEST_DRIVER: "vfs"
         - env:
             TEST_DRIVER: "overlay"
+        - env:
+            TEST_DRIVER: "fuse-overlay"
+        - env:
+            TEST_DRIVER: "fuse-overlay-whiteout"
+        - env:
+            TEST_DRIVER: "btrfs"
 
 
 lint_task:

contrib/cirrus/build_and_test.sh

@@ -28,6 +28,29 @@ case $TEST_DRIVER in
     aufs)
         showrun make STORAGE_DRIVER=aufs local-test-integration local-test-unit
         ;;
+    btrfs)
+        # Fedora: install btrfs-progs, btrfs-progs-devel
+        # Ubuntu: install btrfs-progs, libbtrfs-dev
+        if [[ "$(./hack/btrfs_tag.sh)" =~ exclude_graphdriver_btrfs ]]; then
+            die "Built without btrfs, so we can't test it"
+        fi
+        if ! check_filesystem_supported $TEST_DRIVER ; then
+            die "This CI VM does not support $TEST_DRIVER in its kernel"
+        fi
+        if test -z "$(which mkfs.btrfs 2> /dev/null)" ; then
+            die "This CI VM does not have mkfs.btrfs installed"
+        fi
+        tmpdir=$(mktemp -d)
+        if [ -z "$tmpdir" ]; then
+            die "Error creating temporary directory"
+        fi
+        trap "umount -l $tmpdir; rm -f $GOSRC/$TEST_DRIVER.img" EXIT
+        truncate -s 0 $GOSRC/$TEST_DRIVER.img
+        fallocate -l 1G $GOSRC/$TEST_DRIVER.img
+        mkfs.btrfs $GOSRC/$TEST_DRIVER.img
+        mount -o loop $GOSRC/$TEST_DRIVER.img $tmpdir
+        TMPDIR="$tmpdir" showrun make STORAGE_DRIVER=$TEST_DRIVER local-test-integration local-test-unit
+        ;;
     *)
         die "Unknown/Unsupported \$TEST_DRIVER=$TEST_DRIVER (see .cirrus.yml and $(basename $0))"
         ;;

contrib/cirrus/lib.sh

@@ -115,3 +115,14 @@ install_bats_from_git(){
     mkdir -p ~/.parallel
     touch ~/.parallel/will-cite
 }
+
+check_filesystem_supported(){
+    if ! grep -q "	$1\$" /proc/filesystems ; then
+        modprobe $1 > /dev/null 2> /dev/null || :en
+        if ! grep -q "	$1\$" /proc/filesystems ; then
+            echo "This CI VM does not support $TEST_DRIVER in its kernel"
+	    false
+        fi
+    fi
+    true
+}