Show devicemapper status in "docker info"

This shows the current global diskspace use in "docker info"

api_params.go

@@ -19,18 +19,23 @@ type APIImages struct {
 }
 
 type APIInfo struct {
-	Debug              bool
-	Containers         int
-	Images             int
-	NFd                int    `json:",omitempty"`
-	NGoroutines        int    `json:",omitempty"`
-	MemoryLimit        bool   `json:",omitempty"`
-	SwapLimit          bool   `json:",omitempty"`
-	IPv4Forwarding     bool   `json:",omitempty"`
-	LXCVersion         string `json:",omitempty"`
-	NEventsListener    int    `json:",omitempty"`
-	KernelVersion      string `json:",omitempty"`
-	IndexServerAddress string `json:",omitempty"`
+	Debug                  bool
+	Containers             int
+	Images                 int
+	NFd                    int    `json:",omitempty"`
+	NGoroutines            int    `json:",omitempty"`
+	MemoryLimit            bool   `json:",omitempty"`
+	SwapLimit              bool   `json:",omitempty"`
+	IPv4Forwarding         bool   `json:",omitempty"`
+	LXCVersion             string `json:",omitempty"`
+	NEventsListener        int    `json:",omitempty"`
+	KernelVersion          string `json:",omitempty"`
+	IndexServerAddress     string `json:",omitempty"`
+	DevmapperPool          string `json:",omitempty"`
+	DevmapperDataUsed      uint64 `json:",omitempty"`
+	DevmapperDataTotal     uint64 `json:",omitempty"`
+	DevmapperMetadataUsed  uint64 `json:",omitempty"`
+	DevmapperMetadataTotal uint64 `json:",omitempty"`
 }
 
 type APITop struct {

commands.go

@@ -465,6 +465,11 @@ func (cli *DockerCli) CmdInfo(args ...string) error {
 
 	fmt.Fprintf(cli.out, "Containers: %d\n", out.Containers)
 	fmt.Fprintf(cli.out, "Images: %d\n", out.Images)
+	if out.DevmapperDataTotal != 0 {
+		fmt.Fprintf(cli.out, "Devmapper disk use: Data: %.1f/%.1f Metadata: %.1f/%.1f\n",
+			float64(out.DevmapperDataUsed)/(1024*1024), float64(out.DevmapperDataTotal)/(1024*1024),
+			float64(out.DevmapperMetadataUsed)/(1024*1024), float64(out.DevmapperMetadataTotal)/(1024*1024))
+	}
 	if out.Debug || os.Getenv("DEBUG") != "" {
 		fmt.Fprintf(cli.out, "Debug mode (server): %v\n", out.Debug)
 		fmt.Fprintf(cli.out, "Debug mode (client): %v\n", os.Getenv("DEBUG") != "")
@@ -473,6 +478,7 @@ func (cli *DockerCli) CmdInfo(args ...string) error {
 		fmt.Fprintf(cli.out, "LXC Version: %s\n", out.LXCVersion)
 		fmt.Fprintf(cli.out, "EventsListeners: %d\n", out.NEventsListener)
 		fmt.Fprintf(cli.out, "Kernel Version: %s\n", out.KernelVersion)
+		fmt.Fprintf(cli.out, "Devmapper pool: %s\n", out.DevmapperPool)
 	}
 
 	if len(out.IndexServerAddress) != 0 {

devmapper/deviceset_devmapper.go

@@ -47,6 +47,19 @@ type DeviceSetDM struct {
 	activeMounts     map[string]int
 }
 
+type DiskUsage struct {
+	Used uint64
+	Total uint64
+}
+
+type Status struct {
+	PoolName string
+	DataLoopback string
+	MetadataLoopback string
+	Data DiskUsage
+	Metadata DiskUsage
+}
+
 func getDevName(name string) string {
 	return "/dev/mapper/" + name
 }
@@ -774,6 +787,39 @@ func (devices *DeviceSetDM) SetInitialized(hash string) error {
 	return nil
 }
 
+func (devices *DeviceSetDM) Status() *Status {
+	devices.Lock()
+	defer devices.Unlock()
+
+	status := &Status {}
+
+	if err := devices.ensureInit(); err != nil {
+		return status
+	}
+
+	status.PoolName = devices.getPoolName()
+	status.DataLoopback = path.Join( devices.loopbackDir(), "data")
+	status.MetadataLoopback = path.Join( devices.loopbackDir(), "metadata")
+
+	_, totalSizeInSectors, _, params, err := getStatus(devices.getPoolName())
+	if err == nil {
+		var transactionId, dataUsed, dataTotal, metadataUsed, metadataTotal uint64
+		if _, err := fmt.Sscanf(params, "%d %d/%d %d/%d", &transactionId, &metadataUsed, &metadataTotal, &dataUsed, &dataTotal); err == nil {
+			// Convert from blocks to bytes
+			blockSizeInSectors := totalSizeInSectors / dataTotal;
+
+			status.Data.Used = dataUsed * blockSizeInSectors * 512
+			status.Data.Total = dataTotal * blockSizeInSectors * 512
+
+			// metadata blocks are always 4k
+			status.Metadata.Used = metadataUsed * 4096
+			status.Metadata.Total = metadataTotal * 4096
+		}
+	}
+
+	return status
+}
+
 func (devices *DeviceSetDM) ensureInit() error {
 	if !devices.initialized {
 		devices.initialized = true

server.go

@@ -268,19 +268,26 @@ func (srv *Server) DockerInfo() *APIInfo {
 		kernelVersion = kv.String()
 	}
 
+	devSetInfo := srv.runtime.deviceSet.Status()
+
 	return &APIInfo{
-		Containers:         len(srv.runtime.List()),
-		Images:             imgcount,
-		MemoryLimit:        srv.runtime.capabilities.MemoryLimit,
-		SwapLimit:          srv.runtime.capabilities.SwapLimit,
-		IPv4Forwarding:     !srv.runtime.capabilities.IPv4ForwardingDisabled,
-		Debug:              os.Getenv("DEBUG") != "",
-		NFd:                utils.GetTotalUsedFds(),
-		NGoroutines:        runtime.NumGoroutine(),
-		LXCVersion:         lxcVersion,
-		NEventsListener:    len(srv.events),
-		KernelVersion:      kernelVersion,
-		IndexServerAddress: auth.IndexServerAddress(),
+		Containers:             len(srv.runtime.List()),
+		Images:                 imgcount,
+		MemoryLimit:            srv.runtime.capabilities.MemoryLimit,
+		SwapLimit:              srv.runtime.capabilities.SwapLimit,
+		IPv4Forwarding:         !srv.runtime.capabilities.IPv4ForwardingDisabled,
+		Debug:                  os.Getenv("DEBUG") != "",
+		NFd:                    utils.GetTotalUsedFds(),
+		NGoroutines:            runtime.NumGoroutine(),
+		LXCVersion:             lxcVersion,
+		NEventsListener:        len(srv.events),
+		KernelVersion:          kernelVersion,
+		IndexServerAddress:     auth.IndexServerAddress(),
+		DevmapperPool:          devSetInfo.PoolName,
+		DevmapperDataUsed:      devSetInfo.Data.Used,
+		DevmapperDataTotal:     devSetInfo.Data.Total,
+		DevmapperMetadataUsed:  devSetInfo.Metadata.Used,
+		DevmapperMetadataTotal: devSetInfo.Metadata.Total,
 	}
 }