tailfs: fix startup issues on windows

Starts TailFS for Windows too, initializes shares on startup.

Updates tailscale/corp#16827

Signed-off-by: Percy Wegmann <percy@tailscale.com>

cmd/tailscaled/tailscaled_windows.go

@@ -48,6 +48,7 @@ import (
 	"tailscale.com/net/dns"
 	"tailscale.com/net/netmon"
 	"tailscale.com/net/tstun"
+	"tailscale.com/tailfs/tailfsimpl"
 	"tailscale.com/tsd"
 	"tailscale.com/types/logger"
 	"tailscale.com/types/logid"
@@ -315,6 +316,8 @@ func beWindowsSubprocess() bool {
 	}
 	sys.Set(netMon)
 
+	sys.Set(tailfsimpl.NewFileSystemForRemote(log.Printf))
+
 	publicLogID, _ := logid.ParsePublicID(logID)
 	err = startIPNServer(ctx, log.Printf, publicLogID, sys)
 	if err != nil {

ipn/ipnlocal/local.go

@@ -432,7 +432,7 @@ func NewLocalBackend(logf logger.Logf, logID logid.PublicID, sys *tsd.System, lo
 
 	// initialize TailFS shares from saved state
 	fs, ok := b.sys.TailFSForRemote.GetOK()
-	if !ok {
+	if ok {
 		b.mu.Lock()
 		shares, err := b.tailFSGetSharesLocked()
 		b.mu.Unlock()