support cached volumes, fixes topolvm#1003

* add `C` to VolumeType and OpenTarget consts * `lv.IsThin` should check LV attrs for thin (e.g., cached LVs have a pool but are not necessarily thin) * add tests for cached LVs Signed-off-by: guppy0130 <guppy0130@yahoo.com>
guppy0130 · Jan 10, 2025 · cc0b56d · cc0b56d
1 parent 3305f75
commit cc0b56d
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Showing 4 changed files with 55 additions and 1 deletion.
diff --git a/internal/lvmd/command/lvm.go b/internal/lvmd/command/lvm.go
@@ -474,7 +474,8 @@ func (l *LogicalVolume) Origin(ctx context.Context) (*LogicalVolume, error) {
 
 // IsThin checks if the volume is thin volume or not.
 func (l *LogicalVolume) IsThin() bool {
-	return l.pool != nil
+	// TODO: maybe use const from lvm_lv_attr.go
+	return l.attr[0] == 'V'
 }
 
 // Pool returns thin pool if this is a thin pool, or nil if not.

diff --git a/internal/lvmd/command/lvm_command_test.go b/internal/lvmd/command/lvm_command_test.go
@@ -192,5 +192,39 @@ func Test_lvm_command(t *testing.T) {
 				t.Fatalf("expected error to be %v, got %v", ErrNoMultipleOfSectorSize, err)
 			}
 		})
+
+		t.Run("create cached volume and read it", func(t *testing.T) {
+			// create the cachedevice
+			cache_vg_name := "CACHEDEVICE"
+			cache_loop, err := testutils.MakeLoopbackDevice(ctx, cache_vg_name)
+			if err != nil {
+				t.Fatal(err)
+			}
+			err = testutils.MakeLoopbackVG(ctx, cache_vg_name, cache_loop)
+			if err != nil {
+				t.Fatal(err)
+			}
+			// ensure cache device cleanup
+			defer func() { _ = testutils.CleanLoopbackVG(cache_vg_name, []string{cache_loop}, []string{cache_vg_name}) }()
+			vg, err := FindVolumeGroup(ctx, cache_vg_name)
+			if err != nil {
+				t.Fatal(err)
+			}
+			// create cached LV
+			err = vg.CreateVolume(ctx, "test1", uint64(topolvm.MinimumSectorSize), []string{"tag"}, 0, "", []string{"--type", "writecache", "--cachesize", "10M", "--cachedevice", cache_loop})
+			if err != nil {
+				t.Fatal(err)
+			}
+			vol, err := vg.FindVolume(ctx, "test1")
+			if err != nil {
+				t.Fatal(err)
+			}
+			if vol.IsThin() {
+				t.Fatal("Expected test1 to not be thin (eval lv_attr instead of pool)")
+			}
+			if !strings.Contains(vol.attr, "C") {
+				t.Fatal("Created a LV but without writecache?")
+			}
+		})
 	})
 }
diff --git a/internal/lvmd/command/lvm_lv_attr.go b/internal/lvmd/command/lvm_lv_attr.go
@@ -32,6 +32,7 @@ var (
 type VolumeType rune
 
 const (
+	VolumeTypeCached                     VolumeType = 'C'
 	VolumeTypeMirrored                   VolumeType = 'm'
 	VolumeTypeMirroredNoInitialSync      VolumeType = 'M'
 	VolumeTypeOrigin                     VolumeType = 'o'
@@ -114,6 +115,7 @@ const (
 type OpenTarget rune
 
 const (
+	OpenTargetCache    OpenTarget = 'C'
 	OpenTargetMirror   OpenTarget = 'm'
 	OpenTargetRaid     OpenTarget = 'r'
 	OpenTargetSnapshot OpenTarget = 's'

diff --git a/internal/lvmd/command/lvm_lv_attr_test.go b/internal/lvmd/command/lvm_lv_attr_test.go
@@ -81,6 +81,23 @@ func TestParsedLVAttr(t *testing.T) {
 			},
 			noError,
 		},
+		{
+			"Cache",
+			args{raw: "Cwi-aoC---"},
+			LVAttr{
+				VolumeType:       VolumeTypeCached,
+				Permissions:      PermissionsWriteable,
+				AllocationPolicy: AllocationPolicyInherited,
+				Minor:            MinorFalse,
+				State:            StateActive,
+				Open:             OpenTrue,
+				OpenTarget:       OpenTargetCache,
+				Zero:             ZeroFalse,
+				VolumeHealth:     VolumeHealthOK,
+				SkipActivation:   SkipActivationFalse,
+			},
+			noError,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {