[Feature] support mapped btrfs devices on Linux

cli/commands.go

@@ -25,6 +25,8 @@ const (
 	defaultServerCount = 1
 )
 
+var defaultBindMounts = []string{"/dev/mapper:/dev/mapper"}
+
 // CheckTools checks if the docker API server is responding
 func CheckTools(c *cli.Context) error {
 	log.Print("Checking docker...")

cli/util.go

@@ -2,7 +2,9 @@ package run
 
 import (
 	"fmt"
+	"log"
 	"math/rand"
+	"os"
 	"net"
 	"strconv"
 	"strings"
@@ -90,6 +92,60 @@ func ValidateHostname(name string) error {
 	return nil
 }
 
+// checkDefaultBindMounts takes a volumes slice and a defaults slice
+// and appends the volumes to the defaults, with respect to already set vaules
+// in defaults in volumes, so as to not cause duplication of the same string.
+func checkDefaultBindMounts(volumes []string, defaults []string) []string {
+	newVols := make([]string, 0)
+	destHm := make(map[string]int)
+
+	// populate the desthm with indexes in the defaults
+	for i, v := range defaults {
+		p := strings.Split(v, ":")
+		if len(p) != 2 {
+			continue
+		}
+
+		destPath := p[1]
+		destHm[destPath] = i
+	}
+
+	// check if we overrode a default in the -v, if so, remove
+	// that default bind mount from ever being processed.
+	for _, v := range volumes {
+		p := strings.Split(v, ":")
+		if len(p) != 2 {
+			continue
+		}
+
+		destPath := p[1]
+		if i, ok := destHm[destPath]; ok {
+			defaults[i] = defaults[len(defaults)-1]
+			defaults[len(defaults)-1] = ""
+			defaults = defaults[:len(defaults)-1]
+		}
+	}
+
+	// add the defaults, checking to ensure that the local path (if it's a :) exists
+	for _, v := range defaults {
+		p := strings.Split(v, ":")
+		if len(p) > 1 {
+			// check if the path of a local:remote exists
+			if _, err := os.Stat(p[0]); os.IsNotExist(err) {
+				continue
+			}
+
+			log.Printf("Including extra mount '%s' due to local path existing", v)
+		}
+
+		newVols = append(newVols, v)
+	}
+
+	newVols = append(newVols, volumes...)
+
+	return newVols
+}
+
 func parseApiPort(portSpec string) (*apiPort, error) {
 	var port *apiPort
 	split := strings.Split(portSpec, ":")