Merge pull request #3260 from sagigrimberg/ignore-hidden-devices

sysinfo: Ignore "hidden" sysfs device entries

Author: iwankgb

utils/sysfs/fakesysfs/fake.go

@@ -128,6 +128,10 @@ func (fs *FakeSysFs) GetBlockDeviceNumbers(name string) (string, error) {
 	return "8:0\n", nil
 }
 
+func (fs *FakeSysFs) IsBlockDeviceHidden(name string) (bool, error) {
+	return false, nil
+}
+
 func (fs *FakeSysFs) GetNetworkDevices() ([]os.FileInfo, error) {
 	return []os.FileInfo{&fs.info}, nil
 }

utils/sysfs/sysfs.go

@@ -101,6 +101,9 @@ type SysFs interface {
 	GetBlockDeviceScheduler(string) (string, error)
 	// Get device major:minor number string.
 	GetBlockDeviceNumbers(string) (string, error)
+	// Is the device "hidden" (meaning will not have a device handle)
+	// This is the case with native nvme multipathing.
+	IsBlockDeviceHidden(string) (bool, error)
 
 	GetNetworkDevices() ([]os.FileInfo, error)
 	GetNetworkAddress(string) (string, error)
@@ -212,6 +215,26 @@ func (fs *realSysFs) GetBlockDeviceNumbers(name string) (string, error) {
 	return string(dev), nil
 }
 
+func (fs *realSysFs) IsBlockDeviceHidden(name string) (bool, error) {
+	// See: https://www.kernel.org/doc/Documentation/ABI/stable/sysfs-block
+	//      https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git
+	//        - c8487d854ba5 ("lsblk: Ignore hidden devices")
+	devHiddenPath := path.Join(blockDir, name, "/hidden")
+	hidden, err := os.ReadFile(devHiddenPath)
+	if err != nil && os.IsNotExist(err) {
+		// older OS may not have /hidden sysfs entry, so for sure
+		// it is not a hidden device...
+		return false, nil
+	}
+	if err != nil {
+		return false, fmt.Errorf("failed to read %s: %w", devHiddenPath, err)
+	}
+	if string(hidden) == "1" {
+		return true, nil
+	}
+	return false, nil
+}
+
 func (fs *realSysFs) GetBlockDeviceScheduler(name string) (string, error) {
 	sched, err := os.ReadFile(path.Join(blockDir, name, "/queue/scheduler"))
 	if err != nil {

utils/sysinfo/sysinfo.go

@@ -57,6 +57,16 @@ func GetBlockDeviceInfo(sysfs sysfs.SysFs) (map[string]info.DiskInfo, error) {
 		if strings.HasPrefix(name, "loop") || strings.HasPrefix(name, "ram") || strings.HasPrefix(name, "sr") {
 			continue
 		}
+		// Ignore "hidden" devices (i.e. nvme path device sysfs entries).
+		// These devices are in the form of /dev/nvme$Xc$Yn$Z and will
+		// not have a device handle (i.e. "hidden")
+		isHidden, err := sysfs.IsBlockDeviceHidden(name)
+		if err != nil {
+			return nil, err
+		}
+		if isHidden {
+			continue
+		}
 		diskInfo := info.DiskInfo{
 			Name: name,
 		}