mount/cmount: implement --daemon-timeout flag for OSXFUSE

By default the timeout is 60s which isn't long enough for long
transactions.  The symptoms are rclone just quitting for no reason.
Supplying the --daemon-timeout flag fixes this causing the kernel to
wait longer for rclone.

cmd/cmount/mount.go

@@ -88,6 +88,9 @@ func mountOptions(device string, mountpoint string) (options []string) {
 	if mountlib.WritebackCache {
 		// FIXME? options = append(options, "-o", WritebackCache())
 	}
+	if mountlib.DaemonTimeout != 0 {
+		options = append(options, "-o", fmt.Sprintf("daemon_timeout=%d", int(mountlib.DaemonTimeout.Seconds())))
+	}
 	for _, option := range mountlib.ExtraOptions {
 		options = append(options, "-o", option)
 	}

cmd/mount/mount.go

@@ -5,6 +5,7 @@
 package mount
 
 import (
+	"fmt"
 	"os"
 	"os/signal"
 	"syscall"
@@ -63,6 +64,9 @@ func mountOptions(device string) (options []fuse.MountOption) {
 	if mountlib.WritebackCache {
 		options = append(options, fuse.WritebackCache())
 	}
+	if mountlib.DaemonTimeout != 0 {
+		options = append(options, fuse.DaemonTimeout(fmt.Sprint(int(mountlib.DaemonTimeout.Seconds()))))
+	}
 	if len(mountlib.ExtraOptions) > 0 {
 		fs.Errorf(nil, "-o/--option not supported with this FUSE backend")
 	}

cmd/mountlib/mount.go

@@ -31,8 +31,9 @@ var (
 	ExtraFlags         []string
 	AttrTimeout        = 1 * time.Second // how long the kernel caches attribute for
 	VolumeName         string
-	NoAppleDouble      = true  // use noappledouble by default
-	NoAppleXattr       = false // do not use noapplexattr by default
+	NoAppleDouble      = true        // use noappledouble by default
+	NoAppleXattr       = false       // do not use noapplexattr by default
+	DaemonTimeout      time.Duration // OSXFUSE only
 )
 
 // Check is folder is empty
@@ -274,6 +275,7 @@ be copied to the vfs cache before opening with --vfs-cache-mode full.
 	flags.StringArrayVarP(flagSet, &ExtraFlags, "fuse-flag", "", []string{}, "Flags or arguments to be passed direct to libfuse/WinFsp. Repeat if required.")
 	flags.BoolVarP(flagSet, &Daemon, "daemon", "", Daemon, "Run mount as a daemon (background mode).")
 	flags.StringVarP(flagSet, &VolumeName, "volname", "", VolumeName, "Set the volume name (not supported by all OSes).")
+	flags.DurationVarP(flagSet, &DaemonTimeout, "daemon-timeout", "", DaemonTimeout, "Time limit for rclone to respond to kernel (not supported by all OSes).")
 
 	if runtime.GOOS == "darwin" {
 		flags.BoolVarP(flagSet, &NoAppleDouble, "noappledouble", "", NoAppleDouble, "Sets the OSXFUSE option noappledouble.")