Reduce calls to EFS API

With #850, the new way of allocating GIDs introduced a new call
to the ListAccessPoints endpoint of EFS API, that is generating
problems on systems where EFS CSI driver is under high load
(lots of PVC created within a short time period). In this PR,
we are extracting the ListAccessPoints call from gid_allocator,
moving it one level up. In case of dynamic provisioining of GIDs
we can reuse the ListAccessPoints call to check for the file
system existence (thus removing the DescribeFileSystem call in
such case). In case of a fixed UID/GID, we continue calling
DescribeFileSystem, and no calls to ListAccessPoints.

In addition to the change explained above, gidMin and gidMax have
been converted to int64. #850 made both uid and gid int64, but
gidMin and gidMax were nout touched. Also changing the default
value for gidMin, as the value of 50000 was spamming the logs
with a message coming from gid_allocator (i.e. range bigger than
the max number of access points). Setting the value to 6999000
(the value that gid_allocator was setting by substracting 1000
to gidMax). Removing an unused function and field from
gid_allocator too.

pkg/cloud/cloud.go

@@ -300,10 +300,10 @@ func (c *cloud) ListAccessPoints(ctx context.Context, fileSystemId string) (acce
 	res, err := c.efs.DescribeAccessPointsWithContext(ctx, describeAPInput)
 	if err != nil {
 		if isAccessDenied(err) {
-			return
+			return nil, ErrAccessDenied
 		}
 		if isFileSystemNotFound(err) {
-			return
+			return nil, ErrNotFound
 		}
 		err = fmt.Errorf("List Access Points failed: %v", err)
 		return

pkg/driver/controller.go

@@ -38,8 +38,8 @@ const (
 	AccessPointMode       = "efs-ap"
 	AzName                = "az"
 	BasePath              = "basePath"
-	DefaultGidMin         = 50000
-	DefaultGidMax         = 7000000
+	DefaultGidMin         = int64(6999000)
+	DefaultGidMax         = int64(7000000)
 	DefaultTagKey         = "efs.csi.aws.com/cluster"
 	DefaultTagValue       = "true"
 	DirectoryPerms        = "directoryPerms"
@@ -120,8 +120,8 @@ func (d *Driver) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest)
 		azName           string
 		basePath         string
 		gid              int64
-		gidMin           int
-		gidMax           int
+		gidMin           int64
+		gidMax           int64
 		localCloud       cloud.Cloud
 		provisioningMode string
 		roleArn          string
@@ -189,7 +189,7 @@ func (d *Driver) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest)
 	}
 
 	if value, ok := volumeParams[GidMin]; ok {
-		gidMin, err = strconv.Atoi(value)
+		gidMin, err = strconv.ParseInt(value, 10, 64)
 		if err != nil {
 			return nil, status.Errorf(codes.InvalidArgument, "Failed to parse invalid %v: %v", GidMin, err)
 		}
@@ -203,7 +203,7 @@ func (d *Driver) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest)
 		if gidMin == 0 {
 			return nil, status.Errorf(codes.InvalidArgument, "Missing %v parameter", GidMin)
 		}
-		gidMax, err = strconv.Atoi(value)
+		gidMax, err = strconv.ParseInt(value, 10, 64)
 		if err != nil {
 			return nil, status.Errorf(codes.InvalidArgument, "Failed to parse invalid %v: %v", GidMax, err)
 		}
@@ -241,20 +241,27 @@ func (d *Driver) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest)
 		return nil, err
 	}
 
-	// Check if file system exists. Describe FS handles appropriate error codes
-	if _, err = localCloud.DescribeFileSystem(ctx, accessPointsOptions.FileSystemId); err != nil {
+	// Check if file system exists. Describe FS or List APs handle appropriate error codes
+	// With dynamic uid/gid provisioning we can save a call to describe FS, as list APs fails if FS ID does not exist
+	var accessPoints []*cloud.AccessPoint
+	if uid == -1 || gid == -1 {
+		accessPoints, err = localCloud.ListAccessPoints(ctx, accessPointsOptions.FileSystemId)
+	} else {
+		_, err = localCloud.DescribeFileSystem(ctx, accessPointsOptions.FileSystemId)
+	}
+	if err != nil {
 		if err == cloud.ErrAccessDenied {
 			return nil, status.Errorf(codes.Unauthenticated, "Access Denied. Please ensure you have the right AWS permissions: %v", err)
 		}
 		if err == cloud.ErrNotFound {
 			return nil, status.Errorf(codes.InvalidArgument, "File System does not exist: %v", err)
 		}
-		return nil, status.Errorf(codes.Internal, "Failed to fetch File System info: %v", err)
+		return nil, status.Errorf(codes.Internal, "Failed to fetch Access Points for File System: %v", err)
 	}
 
 	var allocatedGid int64
 	if uid == -1 || gid == -1 {
-		allocatedGid, err = d.gidAllocator.getNextGid(ctx, localCloud, accessPointsOptions.FileSystemId, gidMin, gidMax)
+		allocatedGid, err = d.gidAllocator.getNextGid(accessPointsOptions.FileSystemId, accessPoints, gidMin, gidMax)
 		if err != nil {
 			return nil, err
 		}