.

wcfs/wcfs.go

@@ -295,7 +295,7 @@ package main
 //	  cache for @<rev>/bigfile/file[blk], where
 //
 //	    # see below about file.δtail
-//	    # XXX -> file.δtail.LastBlkRev(#blk, zhead.at)
+//	    # XXX -> file.BlkRevAt(#blk, zhead.at)
 //	    rev = max(file.δtail.by(#blk)) || min(rev ∈ file.δtail) || zhead.at
 //
 //	- invalidate head/bigfile/file[blk] in OS file cache.
@@ -313,7 +313,7 @@ package main
 // 5) after OS file cache was invalidated, we resync zhead to new database
 //    view corresponding to tid.
 //
-// 6) for every file δtail invalidation info about head/data is maintained:
+// 6) for every file δtail invalidation info about head/data is maintained:	XXX -> δFtail
 //
 //	- tailv: [](rev↑, []#blk)
 //	- by:    {} #blk -> []rev↑ in tail
@@ -341,7 +341,7 @@ package main
 //	it is not exact because BTree/Bucket can change (e.g. rebalance)
 //	but still point to the same k->ZBlk.
 //
-//	we also use file.δtail to find either exact blk revision:
+//	we also use file.δtail to find either exact blk revision:	XXX δFtail
 //
 //	  rev(blk) = max(file.δtail.by(#blk) -> []rev↑)
 //
@@ -415,14 +415,12 @@ package main
 // δF    - change in File*s* space
 // δfile - change in File(1) space
 
-// XXX describe locking
+// XXX locking
 //
-// head.zheadMu		write by handleδZ; read by read
-//			-> rlockZHead() + lockZHead() ?
+// head.zheadMu		WLock by handleδZ
+//			RLock by read
 // ...
 
-// XXX locking: test with -race (many bugs are reported)
-
 import (
 	"bufio"
 	"context"
@@ -507,8 +505,6 @@ type Head struct {
 	// uploadBlk signals to zwatcher that there are so many inflight OS cache uploads currently.
 	inflightOSCacheUploads int32
 
-	// XXX move zconn's current transaction to Head here?
-
 	// head/watch opens
 	// XXX protected by ... zheadMu ?
 	wlinkTab map[*WatchLink]struct{}
@@ -545,9 +541,13 @@ type BigFile struct {
 	zfile	*ZBigFile
 
 	// things read/computed from .zfile; constant during lifetime of current transaction.
+	// XXX i.e. changed under zhead.W
 	blksize int64    // zfile.blksize
 	size    int64    // zfile.Size()
 	rev     zodb.Tid // last revision that modified zfile data
+			 // XXX we can't know rev fully as some later blocks could be learnt only
+			 //     while populating δFtail lazily
+			 // XXX or then it is not "constant during lifetime of current txn"
 
 //	// tail change history of this file.
 //	//
@@ -570,6 +570,7 @@ type BigFile struct {
 	// progress of being established. XXX text
 	//
 	// XXX locking -> watchMu?
+	// XXX -> watchTab ?
 	watches map[*Watch]struct{}
 }
 
@@ -667,6 +668,7 @@ func (_ *zodbCacheControl) PCacheClassify(obj zodb.IPersistent) zodb.PCachePolic
 	return 0
 }
 
+/*
 // -------- zhead lock/wait --------
 
 // XXX needed?
@@ -675,6 +677,7 @@ func (head *Head) zheadRLock()   { head.zheadMu.RLock() }
 func (head *Head) zheadRUnlock() { head.zheadMu.RUnlock() }
 func (head *Head) zheadLock()    { head.zheadMu.Lock() }
 func (head *Head) zheadUnlock()  { head.zheadMu.Unlock() }
+*/
 
 // -------- 4) ZODB invalidation -> OS cache --------
 
@@ -683,7 +686,7 @@ func traceZWatch(format string, argv ...interface{}) {
 		return
 	}
 
-	log.Infof("zwatcher: " + format, argv...)	// XXX InfoDepthf
+	log.InfoDepth(1, fmt.Sprintf("zwatcher: " + format, argv...))
 }
 
 // zwatcher watches for ZODB changes.

wcfs/wcfs_test.py

@@ -1785,6 +1785,7 @@ def test_wcfs_watch_2files():
 
 
 # XXX new watch request while previous watch request is in progress (over the same /head/watch handle)
+# XXX @revX/ is automatically removed after some time
 
 
 

wcfs/δftail.go

@@ -425,6 +425,7 @@ func (δFtail *ΔFtail) SliceByFileRev(file *BigFile, lo, hi zodb.Tid) /*readonl
 
 }
 
+// XXX -> BlkRevAt
 // LastBlkRev returns last revision that changed file[blk] as of @at database state.
 //
 // if exact=False - what is returned is only an upper bound for last block revision.