func (c *containerLXC) getDiskLimits() (map[string]deviceBlockLimit, error) {
	result := map[string]deviceBlockLimit{}

	// Build a list of all valid block devices
	validBlocks := []string{}

	dents, err := ioutil.ReadDir("/sys/class/block/")
	if err != nil {
		return nil, err
	}

	for _, f := range dents {
		fPath := filepath.Join("/sys/class/block/", f.Name())
		if shared.PathExists(fmt.Sprintf("%s/partition", fPath)) {
			continue
		}

		if !shared.PathExists(fmt.Sprintf("%s/dev", fPath)) {
			continue
		}

		block, err := ioutil.ReadFile(fmt.Sprintf("%s/dev", fPath))
		if err != nil {
			return nil, err
		}

		validBlocks = append(validBlocks, strings.TrimSuffix(string(block), "\n"))
	}

	// Process all the limits
	blockLimits := map[string][]deviceBlockLimit{}
	for _, k := range c.expandedDevices.DeviceNames() {
		m := c.expandedDevices[k]
		if m["type"] != "disk" {
			continue
		}

		// Apply max limit
		if m["limits.max"] != "" {
			m["limits.read"] = m["limits.max"]
			m["limits.write"] = m["limits.max"]
		}

		// Parse the user input
		readBps, readIops, writeBps, writeIops, err := deviceParseDiskLimit(m["limits.read"], m["limits.write"])
		if err != nil {
			return nil, err
		}

		// Set the source path
		source := shared.HostPath(m["source"])
		if source == "" {
			source = c.RootfsPath()
		}

		// Don't try to resolve the block device behind a non-existing path
		if !shared.PathExists(source) {
			continue
		}

		// Get the backing block devices (major:minor)
		blocks, err := deviceGetParentBlocks(source)
		if err != nil {
			if readBps == 0 && readIops == 0 && writeBps == 0 && writeIops == 0 {
				// If the device doesn't exist, there is no limit to clear so ignore the failure
				continue
			} else {
				return nil, err
			}
		}

		device := deviceBlockLimit{readBps: readBps, readIops: readIops, writeBps: writeBps, writeIops: writeIops}
		for _, block := range blocks {
			blockStr := ""

			if shared.StringInSlice(block, validBlocks) {
				// Straightforward entry (full block device)
				blockStr = block
			} else {
				// Attempt to deal with a partition (guess its parent)
				fields := strings.SplitN(block, ":", 2)
				fields[1] = "0"
				if shared.StringInSlice(fmt.Sprintf("%s:%s", fields[0], fields[1]), validBlocks) {
					blockStr = fmt.Sprintf("%s:%s", fields[0], fields[1])
				}
			}

			if blockStr == "" {
				return nil, fmt.Errorf("Block device doesn't support quotas: %s", block)
			}

			if blockLimits[blockStr] == nil {
				blockLimits[blockStr] = []deviceBlockLimit{}
			}
			blockLimits[blockStr] = append(blockLimits[blockStr], device)
		}
	}

	// Average duplicate limits
	for block, limits := range blockLimits {
		var readBpsCount, readBpsTotal, readIopsCount, readIopsTotal, writeBpsCount, writeBpsTotal, writeIopsCount, writeIopsTotal int64

		for _, limit := range limits {
			if limit.readBps > 0 {
				readBpsCount += 1
				readBpsTotal += limit.readBps
			}

			if limit.readIops > 0 {
				readIopsCount += 1
				readIopsTotal += limit.readIops
			}

			if limit.writeBps > 0 {
				writeBpsCount += 1
				writeBpsTotal += limit.writeBps
			}

			if limit.writeIops > 0 {
				writeIopsCount += 1
				writeIopsTotal += limit.writeIops
			}
		}

		device := deviceBlockLimit{}

		if readBpsCount > 0 {
			device.readBps = readBpsTotal / readBpsCount
		}

		if readIopsCount > 0 {
			device.readIops = readIopsTotal / readIopsCount
		}

		if writeBpsCount > 0 {
			device.writeBps = writeBpsTotal / writeBpsCount
		}

		if writeIopsCount > 0 {
			device.writeIops = writeIopsTotal / writeIopsCount
		}

		result[block] = device
	}

	return result, nil
}
func (c *containerLXC) getDiskLimits() (map[string]deviceBlockLimit, error) {
	result := map[string]deviceBlockLimit{}

	// Build a list of all valid block devices
	validBlocks := []string{}

	dents, err := ioutil.ReadDir("/sys/class/block/")
	if err != nil {
		return nil, err
	}

	for _, f := range dents {
		fPath := filepath.Join("/sys/class/block/", f.Name())
		if shared.PathExists(fmt.Sprintf("%s/partition", fPath)) {
			continue
		}

		if !shared.PathExists(fmt.Sprintf("%s/dev", fPath)) {
			continue
		}

		block, err := ioutil.ReadFile(fmt.Sprintf("%s/dev", fPath))
		if err != nil {
			return nil, err
		}

		validBlocks = append(validBlocks, strings.TrimSuffix(string(block), "\n"))
	}

	// Process all the limits
	blockLimits := map[string][]deviceBlockLimit{}
	for _, k := range c.expandedDevices.DeviceNames() {
		m := c.expandedDevices[k]
		if m["type"] != "disk" {
			continue
		}

		// Apply max limit
		if m["limits.max"] != "" {
			m["limits.read"] = m["limits.max"]
			m["limits.write"] = m["limits.max"]
		}

		// Parse the user input
		readBps, readIops, writeBps, writeIops, err := deviceParseDiskLimit(m["limits.read"], m["limits.write"])
		if err != nil {
			return nil, err
		}

		// Set the source path
		source := shared.HostPath(m["source"])
		if source == "" {
			source = c.RootfsPath()
		}

		// Don't try to resolve the block device behind a non-existing path
		if !shared.PathExists(source) {
			continue
		}

		// Get the backing block devices (major:minor)
		blocks, err := deviceGetParentBlocks(source)
		if err != nil {
			if readBps == 0 && readIops == 0 && writeBps == 0 && writeIops == 0 {
				// If the device doesn't exist, there is no limit to clear so ignore the failure
				continue
			} else {
				return nil, err
			}
		}

		device := deviceBlockLimit{readBps: readBps, readIops: readIops, writeBps: writeBps, writeIops: writeIops}
		for _, block := range blocks {
			blockStr := ""

			if shared.StringInSlice(block, validBlocks) {
				// Straightforward entry (full block device)
				blockStr = block
			} else {
				// Attempt to deal with a partition (guess its parent)
				fields := strings.SplitN(block, ":", 2)
				fields[1] = "0"
				if shared.StringInSlice(fmt.Sprintf("%s:%s", fields[0], fields[1]), validBlocks) {
					blockStr = fmt.Sprintf("%s:%s", fields[0], fields[1])
				}
			}

			if blockStr == "" {
				return nil, fmt.Errorf("Block device doesn't support quotas: %s", block)
			}

			if blockLimits[blockStr] == nil {
				blockLimits[blockStr] = []deviceBlockLimit{}
			}
			blockLimits[blockStr] = append(blockLimits[blockStr], device)
		}
	}

	// Average duplicate limits
	for block, limits := range blockLimits {
		var readBpsCount, readBpsTotal, readIopsCount, readIopsTotal, writeBpsCount, writeBpsTotal, writeIopsCount, writeIopsTotal int64

		for _, limit := range limits {
			if limit.readBps > 0 {
				readBpsCount += 1
				readBpsTotal += limit.readBps
			}

			if limit.readIops > 0 {
				readIopsCount += 1
				readIopsTotal += limit.readIops
			}

			if limit.writeBps > 0 {
				writeBpsCount += 1
				writeBpsTotal += limit.writeBps
			}

			if limit.writeIops > 0 {
				writeIopsCount += 1
				writeIopsTotal += limit.writeIops
			}
		}

		device := deviceBlockLimit{}

		if readBpsCount > 0 {
			device.readBps = readBpsTotal / readBpsCount
		}

		if readIopsCount > 0 {
			device.readIops = readIopsTotal / readIopsCount
		}

		if writeBpsCount > 0 {
			device.writeBps = writeBpsTotal / writeBpsCount
		}

		if writeIopsCount > 0 {
			device.writeIops = writeIopsTotal / writeIopsCount
		}

		result[block] = device
	}

	return result, nil
}
// Block I/O limits