From 7afaac9c6643c61c9146ed90b53e6c0e22ea39d5 Mon Sep 17 00:00:00 2001
From: Niels de Vos <ndevos@redhat.com>
Date: Wed, 22 Jul 2020 15:33:36 +0200
Subject: [PATCH] rbd: implement rbdVolume.isInUse() with go-ceph

The new rbdVolume.isInUse() method will replace the rbdStatus()
function. This removes one more rbd command execution in the
DeleteVolume path.

Signed-off-by: Niels de Vos <ndevos@redhat.com>
---
 internal/rbd/controllerserver.go |  4 ++--
 internal/rbd/rbd_attach.go       |  8 ++++----
 internal/rbd/rbd_util.go         | 22 ++++++++++++++++++++++
 3 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/internal/rbd/controllerserver.go b/internal/rbd/controllerserver.go
index aa86873a5..5de3d1b0b 100644
--- a/internal/rbd/controllerserver.go
+++ b/internal/rbd/controllerserver.go
@@ -613,12 +613,12 @@ func (cs *ControllerServer) DeleteVolume(ctx context.Context, req *csi.DeleteVol
 	}
 	defer cs.VolumeLocks.Release(rbdVol.RequestName)
 
-	found, _, err := rbdStatus(ctx, rbdVol, cr)
+	inUse, err := rbdVol.isInUse()
 	if err != nil {
 		klog.Errorf(util.Log(ctx, "failed getting information for image (%s): (%s)"), rbdVol, err)
 		return nil, status.Error(codes.Internal, err.Error())
 	}
-	if found {
+	if inUse {
 		klog.Errorf(util.Log(ctx, "rbd %s is still being used"), rbdVol)
 		return nil, status.Errorf(codes.Internal, "rbd %s is still being used", rbdVol.RbdImageName)
 	}
diff --git a/internal/rbd/rbd_attach.go b/internal/rbd/rbd_attach.go
index 3542f9660..b1623d73f 100644
--- a/internal/rbd/rbd_attach.go
+++ b/internal/rbd/rbd_attach.go
@@ -190,7 +190,7 @@ func attachRBDImage(ctx context.Context, volOptions *rbdVolume, cr *util.Credent
 			Steps:    rbdImageWatcherSteps,
 		}
 
-		err = waitForrbdImage(ctx, backoff, volOptions, cr)
+		err = waitForrbdImage(ctx, backoff, volOptions)
 
 		if err != nil {
 			return "", err
@@ -246,13 +246,13 @@ func createPath(ctx context.Context, volOpt *rbdVolume, cr *util.Credentials) (s
 	return devicePath, nil
 }
 
-func waitForrbdImage(ctx context.Context, backoff wait.Backoff, volOptions *rbdVolume, cr *util.Credentials) error {
+func waitForrbdImage(ctx context.Context, backoff wait.Backoff, volOptions *rbdVolume) error {
 	imagePath := volOptions.String()
 
 	err := wait.ExponentialBackoff(backoff, func() (bool, error) {
-		used, rbdOutput, err := rbdStatus(ctx, volOptions, cr)
+		used, err := volOptions.isInUse()
 		if err != nil {
-			return false, fmt.Errorf("fail to check rbd image status with: (%v), rbd output: (%s)", err, rbdOutput)
+			return false, fmt.Errorf("fail to check rbd image status: (%w)", err)
 		}
 		if (volOptions.DisableInUseChecks) && (used) {
 			util.UsefulLog(ctx, "valid multi-node attach requested, ignoring watcher in-use result")
diff --git a/internal/rbd/rbd_util.go b/internal/rbd/rbd_util.go
index 47cd3f26c..6c1a3b0ec 100644
--- a/internal/rbd/rbd_util.go
+++ b/internal/rbd/rbd_util.go
@@ -275,6 +275,28 @@ func (rv *rbdVolume) open() (*librbd.Image, error) {
 	return image, nil
 }
 
+// isInUse checks if there is a watcher on the image. It returns true if there
+// is a watcher on the image, otherwise returns false.
+func (rv *rbdVolume) isInUse() (bool, error) {
+	image, err := rv.open()
+	if err != nil {
+		if errors.Is(err, ErrImageNotFound) || errors.Is(err, util.ErrPoolNotFound) {
+			return false, err
+		}
+		// any error should assume something else is using the image
+		return true, err
+	}
+	defer image.Close()
+
+	watchers, err := image.ListWatchers()
+	if err != nil {
+		return false, err
+	}
+
+	// because we opened the image, there is at least one watcher
+	return len(watchers) != 1, nil
+}
+
 // rbdStatus checks if there is watcher on the image.
 // It returns true if there is a watcher on the image, otherwise returns false.
 func rbdStatus(ctx context.Context, pOpts *rbdVolume, cr *util.Credentials) (bool, string, error) {