.

wcfs/wcfs.go

@@ -410,6 +410,7 @@ type Root struct {
 
 	// ZODB DB handle for zstor.
 	// keeps cache of connections for both head/ and @<rev>/ accesses.
+	// XXX head won't be kept here and will be .Resync()'ed explicitly?
 	//
 	// only one connection is used for head/ and only one for each @<rev>.
 	zdb *zodb.DB
@@ -426,12 +427,15 @@ type Root struct {
 type Head struct {
 	nodefs.Node
 	rev   zodb.Tid    // 0 for head/, !0 for @<rev>/
-	bfdir *BigFileDir
-	// at, watch, etc - all implicitly linked to by fs
+	bfdir *BigFileDir // bigfile/
+	// at    - served by .readAt
+	// watch - implicitly linked to by fs
 
 	// ZODB connection for everything under this head
 	zconnMu sync.RWMutex // protects access to zconn & live _objects_ associated with it
 	zconn   *ZConn       // for head/ zwatcher resyncs head.zconn; others only read zconn objects.
+
+	// XXX move zconn's current transaction to Head here?
 }
 
 // /head/watch				- served by Watch.
@@ -447,15 +451,15 @@ type BigFileDir struct {
 	head *Head // parent head/ or @<rev>/
 
 	// {} oid -> <bigfileX>
-	mu  sync.Mutex
-	tab map[zodb.Oid]*BigFile
+	mu      sync.Mutex
+	fileTab map[zodb.Oid]*BigFile
 }
 
 // /(head|<rev>)/bigfile/<bigfileX>	- served by BigFile.
 type BigFile struct {
 	nodefs.Node
 
-	// this BigFile is under head; it views ZODB via head.zconn
+	// this BigFile is under .head/bigfile/; it views ZODB via .head.zconn
 	// parent's BigFileDir.head is the same.
 	head	*Head
 
@@ -465,8 +469,8 @@ type BigFile struct {
 	// zbf.Size(). It is constant during liftime of current transaction.
 	zbfSize int64
 
-	// change history of this file.
-	δFtail *ΔTailI64 // [](rev, []#blk)
+	// tail change history of this file.
+	δFtail *ΔTailI64 // [](rev↑, []#blk)
 
 	// TODO -> δFtail
 	// lastChange	zodb.Tid // last change to whole bigfile as of .zconn.At view
@@ -578,7 +582,7 @@ func (r *Root) zhandle1(zevent zodb.WatchEvent) {
 			// bfdir locking: similarly not needed, since we are
 			// exclusively holding head lock.
 			for zfile, objBlk := range obj.blkBoundTo() {
-				file, ok := bfdir.tab[zfile.POid()]
+				file, ok := bfdir.fileTab[zfile.POid()]
 				if !ok {
 					// even though zfile is in ZODB cache, the
 					// filesystem already forgot about this file.
@@ -690,6 +694,14 @@ func (root *Root) mkrevfile(rev zodb.Tid, fid zodb.Oid) (_ *BigFile, err error)
 
 // ----------------------------------------
 
+// /(head|<rev>)/at -> readAt serves read.
+func (h *Head) readAt() []byte {
+	h.zconnMu.RLock()
+	defer h.zconnMu.RUnlock()
+
+	return []byte(h.zconn.At().String())
+}
+
 // /(head|<rev>)/bigfile/ -> Lookup receives client request to create /(head|<rev>)/bigfile/<bigfileX>.
 func (bfdir *BigFileDir) Lookup(out *fuse.Attr, name string, fctx *fuse.Context) (*nodefs.Inode, fuse.Status) {
 	f, err := bfdir.lookup(out, name, fctx)
@@ -720,7 +732,7 @@ func (bfdir *BigFileDir) lookup(out *fuse.Attr, name string, fctx *fuse.Context)
 
 	// check to see if dir(oid) is already there
 	bfdir.mu.Lock()
-	f, already := bfdir.tab[oid]
+	f, already := bfdir.fileTab[oid]
 	bfdir.mu.Unlock()
 
 	if already {
@@ -736,14 +748,14 @@ func (bfdir *BigFileDir) lookup(out *fuse.Attr, name string, fctx *fuse.Context)
 	// relock bfdir and either register f or, if the file was maybe
 	// simultanously created while we were not holding bfdir.mu, return that.
 	bfdir.mu.Lock()
-	f2, already := bfdir.tab[oid]
+	f2, already := bfdir.fileTab[oid]
 	if already {
 		bfdir.mu.Unlock()
 		f.Close()
 		return f2, nil
 	}
 
-	bfdir.tab[oid] = f
+	bfdir.fileTab[oid] = f
 	bfdir.mu.Unlock()
 
 	// mkfile takes filesystem treeLock - do it outside bfdir.mu
@@ -813,9 +825,9 @@ func (root *Root) mkdir(name string, fctx *fuse.Context) (_ *nodefs.Inode, err e
 	}
 
 	bfdir := &BigFileDir{
-		Node: nodefs.NewDefaultNode(),
-		head: revDir,
-		tab:  make(map[zodb.Oid]*BigFile),
+		Node:    nodefs.NewDefaultNode(),
+		head:    revDir,
+		fileTab: make(map[zodb.Oid]*BigFile),
 	}
 	revDir.bfdir = bfdir
 
@@ -1097,14 +1109,6 @@ func (f *BigFile) readBlk(ctx context.Context, blk int64, dest []byte) error {
 }
 
 
-// /(head|<rev>)/at -> readAt serves read.
-func (h *Head) readAt() []byte {
-	h.zconnMu.RLock()
-	defer h.zconnMu.RUnlock()
-	return []byte(h.zconn.At().String())
-}
-
-
 
 
 
@@ -1170,9 +1174,9 @@ func main() {
 		zconn: zhead,
 	}
 	bfdir := &BigFileDir{
-		Node:  nodefs.NewDefaultNode(),
-		head:  head,
-		tab:   make(map[zodb.Oid]*BigFile),
+		Node:    nodefs.NewDefaultNode(),
+		head:    head,
+		fileTab: make(map[zodb.Oid]*BigFile),
 	}
 	head.bfdir = bfdir