distro/*: allow /boot to be customized

Since the LVM support was added to all distros, our disk
related code is adaptive, i.e. we will set the correct BLS
and grub2 prefix if there a `boot` partiton is present in
the layout after all customizations happen, which includes
LVMification.
One thing that was not yet fully working was layouts that
do not yet have a `/boot` partition but allow LVMification.
In that case `NewPartitionTable` and if `/boot` was the
first (or only) customization, would LVMify the partition
which in turn would create the `/boot` partition; but after
`newPT.ensureLVM()` the call to `newPT.createFilesystem`
with `/boot` would try to create another `/boot` mountpoint.
In order to deal with this situation correctly we are now
using a two phase approach: 1) enlarge existing mountpoints
and collect new ones. 2) if there are new ones and LMVify
was allowed, switch to LVM layout. Do a second pass and now
create or enlarge existing partitions, handling `/boot` in
the process.

internal/client/compose_test.go

@@ -553,7 +553,7 @@ func TestComposeUnsupportedMountPointV0(t *testing.T) {
 		description="TestComposeUnsupportedMountPointV0"
 		version="0.0.1"
 		[[customizations.filesystem]]
-		mountpoint = "/boot"
+		mountpoint = "/etc"
 		size = 4294967296
 		`
 	resp, err := PostTOMLBlueprintV0(testState.socket, bp)

internal/disk/disk.go

@@ -54,6 +54,7 @@ const (
 
 var MountpointPolicies = NewPathPolicies(map[string]PathPolicy{
 	"/":     {Exact: true},
+	"/boot": {Exact: true},
 	"/var":  {},
 	"/opt":  {},
 	"/srv":  {},

internal/disk/disk_test.go

@@ -617,6 +617,36 @@ func TestMinimumSizes(t *testing.T) {
 	}
 }
 
+func TestNewBootWithSizeLVMify(t *testing.T) {
+	pt := testPartitionTables["plain-noboot"]
+	assert := assert.New(t)
+
+	// math/rand is good enough in this case
+	/* #nosec G404 */
+	rng := rand.New(rand.NewSource(13))
+
+	custom := []blueprint.FilesystemCustomization{
+		{
+			Mountpoint: "/boot",
+			MinSize:    700 * MiB,
+		},
+	}
+
+	mpt, err := NewPartitionTable(&pt, custom, uint64(3*GiB), true, rng)
+	assert.NoError(err)
+
+	for idx, c := range custom {
+		mnt, minSize := c.Mountpoint, c.MinSize
+		path := entityPath(mpt, mnt)
+		assert.NotNil(path, "[%d] mountpoint %q not found", idx, mnt)
+		parent := path[1]
+		part, ok := parent.(*Partition)
+		assert.True(ok, "%q parent (%v) is not a partition", mnt, parent)
+		assert.GreaterOrEqual(part.GetSize(), minSize,
+			"[%d] %q size %d should be greater or equal to %d", idx, mnt, part.GetSize(), minSize)
+	}
+}
+
 func collectEntities(pt *PartitionTable) []Entity {
 	entities := make([]Entity, 0)
 	collector := func(ent Entity, path []Entity) error {

internal/disk/partition_table.go

@@ -21,17 +21,33 @@ type PartitionTable struct {
 
 func NewPartitionTable(basePT *PartitionTable, mountpoints []blueprint.FilesystemCustomization, imageSize uint64, lvmify bool, rng *rand.Rand) (*PartitionTable, error) {
 	newPT := basePT.Clone().(*PartitionTable)
+	newMountpoints := []blueprint.FilesystemCustomization{}
+
+	// first pass: enlarge existing mountpoints and collect new ones
 	for _, mnt := range mountpoints {
+		if path := entityPath(newPT, mnt.Mountpoint); len(path) != 0 {
+			size := newPT.AlignUp(clampFSSize(mnt.Mountpoint, mnt.MinSize))
+			resizeEntityBranch(path, size)
+		} else {
+			newMountpoints = append(newMountpoints, mnt)
+		}
+	}
+
+	// if there is any new mountpoint and lvmify is enabled, ensure we have LVM layout
+	if lvmify && len(newMountpoints) > 0 {
+		err := newPT.ensureLVM()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	// second pass: deal with new mountpoints and newly created ones, after switching to
+	// the LVM layout, if requested, which might introduce new mount points, i.e. `/boot`
+	for _, mnt := range newMountpoints {
 		size := newPT.AlignUp(clampFSSize(mnt.Mountpoint, mnt.MinSize))
 		if path := entityPath(newPT, mnt.Mountpoint); len(path) != 0 {
 			resizeEntityBranch(path, size)
 		} else {
-			if lvmify {
-				err := newPT.ensureLVM()
-				if err != nil {
-					return nil, err
-				}
-			}
 			if err := newPT.createFilesystem(mnt.Mountpoint, size); err != nil {
 				return nil, err
 			}
@@ -467,7 +483,13 @@ func (pt *PartitionTable) FindMountable(mountpoint string) Mountable {
 
 func clampFSSize(mountpoint string, size uint64) uint64 {
 	// set a minimum size of 1GB for all mountpoints
+	// with the exception for '/boot' (= 500 MB)
 	var minSize uint64 = 1073741824
+
+	if mountpoint == "/boot" {
+		minSize = 524288000
+	}
+
 	if minSize > size {
 		return minSize
 	}

internal/distro/fedora/distro_test.go

@@ -529,7 +529,7 @@ func TestDistro_CustomFileSystemManifestError(t *testing.T) {
 			Filesystem: []blueprint.FilesystemCustomization{
 				{
 					MinSize:    1024,
-					Mountpoint: "/boot",
+					Mountpoint: "/etc",
 				},
 			},
 		},
@@ -544,7 +544,7 @@ func TestDistro_CustomFileSystemManifestError(t *testing.T) {
 			} else if imgTypeName == "fedora-iot-installer" {
 				continue
 			} else {
-				assert.EqualError(t, err, "The following custom mountpoints are not supported [\"/boot\"]")
+				assert.EqualError(t, err, "The following custom mountpoints are not supported [\"/etc\"]")
 			}
 		}
 	}

internal/distro/rhel7/distro_test.go

@@ -275,7 +275,7 @@ func TestDistro_CustomFileSystemManifestError(t *testing.T) {
 			Filesystem: []blueprint.FilesystemCustomization{
 				{
 					MinSize:    1024,
-					Mountpoint: "/boot",
+					Mountpoint: "/etc",
 				},
 			},
 		},
@@ -285,7 +285,7 @@ func TestDistro_CustomFileSystemManifestError(t *testing.T) {
 		for _, imgTypeName := range arch.ListImageTypes() {
 			imgType, _ := arch.GetImageType(imgTypeName)
 			_, err := imgType.Manifest(bp.Customizations, distro.ImageOptions{}, nil, nil, nil, 0)
-			assert.EqualError(t, err, "The following custom mountpoints are not supported [\"/boot\"]")
+			assert.EqualError(t, err, "The following custom mountpoints are not supported [\"/etc\"]")
 		}
 	}
 }

internal/distro/rhel8/distro_test.go

@@ -614,7 +614,7 @@ func TestDistro_CustomFileSystemManifestError(t *testing.T) {
 			Filesystem: []blueprint.FilesystemCustomization{
 				{
 					MinSize:    1024,
-					Mountpoint: "/boot",
+					Mountpoint: "/etc",
 				},
 			},
 		},
@@ -629,7 +629,7 @@ func TestDistro_CustomFileSystemManifestError(t *testing.T) {
 			} else if imgTypeName == "edge-installer" || imgTypeName == "edge-simplified-installer" || imgTypeName == "edge-raw-image" {
 				continue
 			} else {
-				assert.EqualError(t, err, "The following custom mountpoints are not supported [\"/boot\"]")
+				assert.EqualError(t, err, "The following custom mountpoints are not supported [\"/etc\"]")
 			}
 		}
 	}

internal/distro/rhel90/distro_test.go

@@ -606,7 +606,7 @@ func TestDistro_CustomFileSystemManifestError(t *testing.T) {
 			Filesystem: []blueprint.FilesystemCustomization{
 				{
 					MinSize:    1024,
-					Mountpoint: "/boot",
+					Mountpoint: "/etc",
 				},
 			},
 		},
@@ -621,7 +621,7 @@ func TestDistro_CustomFileSystemManifestError(t *testing.T) {
 			} else if imgTypeName == "edge-installer" || imgTypeName == "edge-simplified-installer" || imgTypeName == "edge-raw-image" {
 				continue
 			} else {
-				assert.EqualError(t, err, "The following custom mountpoints are not supported [\"/boot\"]")
+				assert.EqualError(t, err, "The following custom mountpoints are not supported [\"/etc\"]")
 			}
 		}
 	}

test/cases/filesystem.sh

@@ -242,7 +242,7 @@ mountpoint = "/etc"
 size = 131072000
 
 [[customizations.filesystem]]
-mountpoint = "/boot"
+mountpoint = "/lost+found"
 size = 131072000
 
 EOF
@@ -254,7 +254,7 @@ build_image "$BLUEPRINT_FILE" rhel85-custom-filesystem-fail qcow2 true
 FAILED_MOUNTPOINTS=()
 
 greenprint "💬 Checking expected failures"
-for MOUNTPOINT in '/etc' '/boot' ; do
+for MOUNTPOINT in '/etc' '/lost+found' ; do
   if ! [[ $ERROR_MSG == *"$MOUNTPOINT"* ]]; then
     FAILED_MOUNTPOINTS+=("$MOUNTPOINT")
   fi