.

wcfs/misc.go

@@ -86,6 +86,8 @@ func err2LogStatus(err error) fuse.Status {
 		return fuse.EINTR
 	}
 
+	// XXX io.ErrClosedPipe -> EPIPE?
+
 	// otherwise log as warnings EINVAL and as errors everything else
 	switch e.(type) {
 	case *eInvalError:
@@ -297,9 +299,6 @@ type skFile struct {
 //
 // After file socket is created, File return should be given to kernel for the
 // socket to be connected to an opened file.
-//
-// Note: the node opening which gives FileSock, should not be "regular" - else
-// read/write will be serialized by kernel (git.kernel.org/linus/9c225f2655)
 func NewFileSock() *FileSock {
 	sk := &FileSock{}
 	f  := &skFile{
@@ -324,7 +323,10 @@ func NewFileSock() *FileSock {
 // to be connected to the socket.
 func (sk *FileSock) File() nodefs.File {
 	// nonseekable & directio for opened file to have streaming semantic as
-	// if it was a socket.
+	// if it was a socket. FOPEN_STREAM is used so that both read and write
+	// could be run simultaneously:
+	//
+	// https://marc.info/?l=linux-fsdevel&m=155364064907309&w=2
 	return &nodefs.WithFlags{
 		File:      sk.file,
 		FuseFlags: fuse.FOPEN_STREAM | fuse.FOPEN_NONSEEKABLE | fuse.FOPEN_DIRECT_IO,

wcfs/wcfs.go

@@ -1248,19 +1248,6 @@ retry:
 
 // ---- Watch server ----
 
-func (watch *Watch) GetAttr(out *fuse.Attr, f nodefs.File, fctx *fuse.Context) fuse.Status {
-	st := watch.fsNode.GetAttr(out, f, fctx)
-	// represent ourself as XXX (FileSock requirement)
-	// XXX S_IFSOCK does not work (LOOKUP returns inode, open gives: "No such device or address")
-	// XXX S_IFIFO  does not work (the kernel shows the file, but it being
-	//     FIFO makes the data go through kernel pipe, not via FUSE filesystem)
-	// XXX S_IFLNK  - the kernel wants to follow the link
-	// XXX S_IFDIR  - os.open complains "is a directory" (maybe could workaround)
-	// XXX S_IFCHR	- fusermount always adds nodev mount option -> the device cannot be accessed
-	//out.Mode = syscall.S_IFSOCK | 0644
-	return st
-}
-
 // Open serves /head/watch opens.
 func (watch *Watch) Open(flags uint32, fctx *fuse.Context) (nodefs.File, fuse.Status) {
 	// XXX check flags?
@@ -1280,7 +1267,7 @@ func (watch *Watch) Open(flags uint32, fctx *fuse.Context) (nodefs.File, fuse.St
 }
 
 // serve serves client originated watch requests.
-// XXX serves rx?
+// XXX serves rx? (-> and routes client replies ...)
 func (w *Watcher) serve() {
 	err := w._serve()
 	_ = err
@@ -1294,17 +1281,19 @@ func (w *Watcher) _serve() (err error) {
 	defer xerr.Contextf(&err, "watcher %d: serve", w.id)
 	r := bufio.NewReader(w.sk)
 
+	// XXX write to peer if it was logical error on client side
+	// XXX on which stream? -1?
+
 	for {
 		l, err := r.ReadString('\n')	// XXX limit accepted line len not to DOS
 		if err != nil {
-			return err	// XXX err ctx?
+			return err
 		}
 
 		fmt.Printf("S: watch: rx: %q\n", l)
 
 		stream, msg, err := parseWatchFrame(l)
 		if err != nil {
-			// XXX write to peer too? (on which stream? -1?)
 			return fmt.Errorf("rx: %s", err)
 		}
 
@@ -1317,7 +1306,7 @@ func (w *Watcher) _serve() (err error) {
 			w.rxMu.Unlock()
 
 			if rxq == nil {
-				return fmt.Errorf("rx %d: reply on unexpected streamd", stream)
+				return fmt.Errorf("rx %d: reply on unexpected stream", stream)
 			}
 			rxq <- msg
 			continue
@@ -1326,7 +1315,6 @@ func (w *Watcher) _serve() (err error) {
 		// client-initiated request
 		oid, at, err := parseWatch(msg)
 		if err != nil {
-			// XXX write to peer too
 			return fmt.Errorf("rx %d: %s", stream, err)
 		}