.

wcfs/wcfs.go

@@ -1046,22 +1046,6 @@ func (f *BigFile) invalidateBlk(ctx context.Context, blk int64) (err error) {
 	if int64(len(blkdata)) == blksize {
 		func() {
 			// store retrieved data back to OS cache for file @<rev>/file[blk]
-			//
-			// XXX there is deadlock here:
-			//
-			// T1: Lookup "head"
-			//	-> nodefs.rawBridge.lookupLock.Lock
-			//	-> zheadMu.RLock
-			//	   `-> block (waiting for handleδZ to WUnlock zheadMu)
-			//
-			// T2 (this thread): Lookup "@<revX>"
-			//	-> nodefs.rawBridge.lookupLock.Lock
-			//	   `-> block (waiting for T1)
-			//
-			// see https://github.com/hanwen/go-fuse/commit/d0fca860
-			// for when rawBridge.lookupLock was introduced.
-			//
-			// -> should be fixed: https://review.gerrithub.io/c/hanwen/go-fuse/+/487809
 			blkrev, _ := f.LastBlkRev(ctx, blk, f.head.zconn.At())
 			frev, funlock, err := groot.lockRevFile(blkrev, f.zfile.POid())
 			if err != nil {

wcfs/δftail.go

@@ -64,11 +64,11 @@ import (
 //
 // XXX concurrent use
 //
-// XXX see also zodb.ΔTail
+// See also zodb.ΔTail
 type ΔFtail struct {
 	// ΔFtail merges btree.ΔTail with history of ZBlk
 	δBtail  *ΔBtail
-	fileIdx map[*btree.LOBTree]SetBigFile	// root -> {} BigFile	XXX root -> oid?
+	fileIdx map[*btree.LOBTree]SetBigFile	// root -> {} BigFile XXX root -> oid? XXX as of @head?
 
 	// data with δF changes. Actual for part of tracked set that was taken
 	// into account.
@@ -191,6 +191,8 @@ func (δFtail *ΔFtail) Track(file *BigFile, blk int64, path []btree.LONode, zbl
 // Objects in Zhead must not be modified.
 // During call to Update zhead must not be otherwise used - even for reading.
 func (δFtail *ΔFtail) Update(δZ *zodb.EventCommit, zhead *ZConn) ΔF {
+	// XXX δFtail.update() first?
+
 	δB := δFtail.δBtail.Update(δZ)
 	δF := ΔF{Rev: δB.Rev, ByFile: make(map[*BigFile]*ΔFile)}