From c5ac901e8dac48d45079095a6bab04674872b28b Mon Sep 17 00:00:00 2001
From: Anis Elleuch <vadmeste@users.noreply.github.com>
Date: Thu, 1 Aug 2019 22:13:06 +0100
Subject: [PATCH] xl: Fix healing empty directories (#8013)

After some extensive refactors, it turned out empty directories
are not healed and heal status is also not reported correctly.

This commit fixes it and adds the appropriate unit tests
---
 cmd/xl-v1-healing.go      |  9 +++--
 cmd/xl-v1-healing_test.go | 76 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/cmd/xl-v1-healing.go b/cmd/xl-v1-healing.go
index a8df3f94d..29abbb376 100644
--- a/cmd/xl-v1-healing.go
+++ b/cmd/xl-v1-healing.go
@@ -501,10 +501,14 @@ func (xl xlObjects) healObjectDir(ctx context.Context, bucket, object string, dr
 			drive = storageDisks[i].String()
 		}
 		switch err {
+		case nil:
+			hr.Before.Drives[i] = madmin.HealDriveInfo{State: madmin.DriveStateOk}
+			hr.After.Drives[i] = madmin.HealDriveInfo{State: madmin.DriveStateOk}
 		case errDiskNotFound:
 			hr.Before.Drives[i] = madmin.HealDriveInfo{State: madmin.DriveStateOffline}
 			hr.After.Drives[i] = madmin.HealDriveInfo{State: madmin.DriveStateOffline}
-		case errVolumeNotFound:
+		case errVolumeNotFound, errFileNotFound:
+			// Bucket or prefix/directory not found
 			hr.Before.Drives[i] = madmin.HealDriveInfo{Endpoint: drive, State: madmin.DriveStateMissing}
 			hr.After.Drives[i] = madmin.HealDriveInfo{Endpoint: drive, State: madmin.DriveStateMissing}
 		default:
@@ -517,7 +521,8 @@ func (xl xlObjects) healObjectDir(ctx context.Context, bucket, object string, dr
 	}
 	for i, err := range errs {
 		switch err {
-		case errVolumeNotFound:
+		case errVolumeNotFound, errFileNotFound:
+			// Bucket or prefix/directory not found
 			merr := storageDisks[i].MakeVol(pathJoin(bucket, object))
 			switch merr {
 			case nil, errVolumeExists:
diff --git a/cmd/xl-v1-healing_test.go b/cmd/xl-v1-healing_test.go
index 70a968f15..893932670 100644
--- a/cmd/xl-v1-healing_test.go
+++ b/cmd/xl-v1-healing_test.go
@@ -250,3 +250,79 @@ func TestHealObjectXL(t *testing.T) {
 		t.Errorf("Expected %v but received %v", InsufficientReadQuorum{}, err)
 	}
 }
+
+// Tests healing of empty directories
+func TestHealEmptyDirectoryXL(t *testing.T) {
+	nDisks := 16
+	fsDirs, err := getRandomDisks(nDisks)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer removeRoots(fsDirs)
+
+	// Everything is fine, should return nil
+	obj, _, err := initObjectLayer(mustGetNewEndpointList(fsDirs...))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	bucket := "bucket"
+	object := "empty-dir/"
+	var opts ObjectOptions
+
+	err = obj.MakeBucketWithLocation(context.Background(), bucket, "")
+	if err != nil {
+		t.Fatalf("Failed to make a bucket - %v", err)
+	}
+
+	// Upload an empty directory
+	_, err = obj.PutObject(context.Background(), bucket, object, mustGetPutObjReader(t, bytes.NewReader([]byte{}), 0, "", ""), opts)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Remove the object backend files from the first disk.
+	xl := obj.(*xlObjects)
+	firstDisk := xl.storageDisks[0]
+	err = firstDisk.DeleteFile(bucket, object)
+	if err != nil {
+		t.Fatalf("Failed to delete a file - %v", err)
+	}
+
+	// Heal the object
+	hr, err := obj.HealObject(context.Background(), bucket, object, false, false, madmin.HealNormalScan)
+	if err != nil {
+		t.Fatalf("Failed to heal object - %v", err)
+	}
+
+	// Check if the empty directory is restored in the first disk
+	_, err = firstDisk.StatVol(pathJoin(bucket, object))
+	if err != nil {
+		t.Fatalf("Expected object to be present but stat failed - %v", err)
+	}
+
+	// Check the state of the object in the first disk (should be missing)
+	if hr.Before.Drives[0].State != madmin.DriveStateMissing {
+		t.Fatalf("Unexpected drive state: %v", hr.Before.Drives[0].State)
+	}
+
+	// Check the state of all other disks (should be ok)
+	for i, h := range append(hr.Before.Drives[1:], hr.After.Drives...) {
+		if h.State != madmin.DriveStateOk {
+			t.Fatalf("Unexpected drive state (%d): %v", i+1, h.State)
+		}
+	}
+
+	// Heal the same object again
+	hr, err = obj.HealObject(context.Background(), bucket, object, false, false, madmin.HealNormalScan)
+	if err != nil {
+		t.Fatalf("Failed to heal object - %v", err)
+	}
+
+	// Check that Before & After states are all okay
+	for i, h := range append(hr.Before.Drives, hr.After.Drives...) {
+		if h.State != madmin.DriveStateOk {
+			t.Fatalf("Unexpected drive state (%d): %v", i+1, h.State)
+		}
+	}
+}