fix: eliminate the duplicate mount entries in /proc/mounts (#524)

Author: agneum

engine/internal/retrieval/engine/postgres/logical/logical.go

@@ -28,7 +28,7 @@ func isAlreadyMounted(mounts []mount.Mount, dir string) bool {
 	dir = strings.Trim(dir, "/")
 
 	for _, mountPoint := range mounts {
-		if strings.Trim(mountPoint.Source, "/") == dir {
+		if strings.Trim(mountPoint.Source, "/") == dir || strings.Trim(mountPoint.Target, "/") == dir {
 			return true
 		}
 	}

engine/internal/retrieval/engine/postgres/logical/logical_test.go

@@ -38,6 +38,16 @@ func TestIsAlreadyMounted(t *testing.T) {
 			dumpLocation:   "/var/lib/dblab/new_pool/dump",
 			expectedResult: false,
 		},
+		{
+			source:         []mount.Mount{{Source: "/host/path/dump", Target: "/var/lib/dblab/pool/dump"}},
+			dumpLocation:   "/var/lib/dblab/pool/dump",
+			expectedResult: true,
+		},
+		{
+			source:         []mount.Mount{{Source: "/host/path/dump", Target: "/var/lib/dblab/pool/dump/"}},
+			dumpLocation:   "/var/lib/dblab/pool/dump",
+			expectedResult: true,
+		},
 	}
 
 	for _, tc := range testCases {

engine/internal/retrieval/engine/postgres/tools/tools.go

@@ -183,6 +183,7 @@ func AddVolumesToHostConfig(ctx context.Context, docker *client.Client, hostConf
 // GetMountsFromMountPoints creates a list of mounts.
 func GetMountsFromMountPoints(dataDir string, mountPoints []types.MountPoint) []mount.Mount {
 	mounts := make([]mount.Mount, 0, len(mountPoints))
+	seen := make(map[string]struct{})
 
 	for _, mountPoint := range mountPoints {
 		// Rewrite mounting to data directory.
@@ -192,6 +193,18 @@ func GetMountsFromMountPoints(dataDir string, mountPoints []types.MountPoint) []
 			mountPoint.Destination = dataDir
 		}
 
+		// Deduplicate mounts by normalizing paths and checking both source and target.
+		normalizedSource := strings.Trim(mountPoint.Source, "/")
+		normalizedTarget := strings.Trim(mountPoint.Destination, "/")
+		mountKey := normalizedSource + "|" + normalizedTarget
+
+		if _, ok := seen[mountKey]; ok {
+			log.Dbg("skipping duplicate mount", mountPoint.Source, "to", mountPoint.Destination)
+			continue
+		}
+
+		seen[mountKey] = struct{}{}
+
 		mounts = append(mounts, mount.Mount{
 			Type:     mountPoint.Type,
 			Source:   mountPoint.Source,

engine/internal/retrieval/engine/postgres/tools/tools_test.go

@@ -37,11 +37,13 @@ func TestIfDirectoryEmpty(t *testing.T) {
 
 func TestGetMountsFromMountPoints(t *testing.T) {
 	testCases := []struct {
+		name           string
 		dataDir        string
 		mountPoints    []types.MountPoint
 		expectedPoints []mount.Mount
 	}{
 		{
+			name:    "simple mount without transformation",
 			dataDir: "/var/lib/dblab/clones/dblab_clone_6000/data",
 			mountPoints: []types.MountPoint{{
 				Source:      "/var/lib/pgsql/data",
@@ -56,8 +58,8 @@ func TestGetMountsFromMountPoints(t *testing.T) {
 				},
 			}},
 		},
-
 		{
+			name:    "mount with path transformation",
 			dataDir: "/var/lib/dblab/clones/dblab_clone_6000/data",
 			mountPoints: []types.MountPoint{{
 				Source:      "/var/lib/postgresql",
@@ -72,10 +74,44 @@ func TestGetMountsFromMountPoints(t *testing.T) {
 				},
 			}},
 		},
+		{
+			name:    "deduplicate identical mounts",
+			dataDir: "/var/lib/dblab/data",
+			mountPoints: []types.MountPoint{
+				{Source: "/host/dump", Destination: "/var/lib/dblab/dump"},
+				{Source: "/host/dump", Destination: "/var/lib/dblab/dump"},
+			},
+			expectedPoints: []mount.Mount{{
+				Source:   "/host/dump",
+				Target:   "/var/lib/dblab/dump",
+				ReadOnly: true,
+				BindOptions: &mount.BindOptions{
+					Propagation: "",
+				},
+			}},
+		},
+		{
+			name:    "deduplicate mounts with trailing slashes",
+			dataDir: "/var/lib/dblab/data",
+			mountPoints: []types.MountPoint{
+				{Source: "/host/dump/", Destination: "/var/lib/dblab/dump"},
+				{Source: "/host/dump", Destination: "/var/lib/dblab/dump/"},
+			},
+			expectedPoints: []mount.Mount{{
+				Source:   "/host/dump/",
+				Target:   "/var/lib/dblab/dump",
+				ReadOnly: true,
+				BindOptions: &mount.BindOptions{
+					Propagation: "",
+				},
+			}},
+		},
 	}
 
 	for _, tc := range testCases {
-		mounts := GetMountsFromMountPoints(tc.dataDir, tc.mountPoints)
-		assert.Equal(t, tc.expectedPoints, mounts)
+		t.Run(tc.name, func(t *testing.T) {
+			mounts := GetMountsFromMountPoints(tc.dataDir, tc.mountPoints)
+			assert.Equal(t, tc.expectedPoints, mounts)
+		})
 	}
 }

engine/test/_cleanup.sh

@@ -3,7 +3,7 @@ set -euxo pipefail
 
 DLE_TEST_MOUNT_DIR="/var/lib/test/dblab_mount"
 DLE_TEST_POOL_NAME="test_dblab_pool"
-TMP_DATA_DIR="/tmp/dle_test/logical_generic"
+TMP_DATA_DIR="/tmp/dle_test"
 ZFS_FILE="$(pwd)/zfs_file"
 
 # Stop and remove test Docker containers