.

wcfs/wcfs.go

@@ -364,14 +364,15 @@ package main
 //   and a client that wants @rev data will get @rev data, even if it was this
 //   "old" client that triggered the pagefault(~).
 //
+// XXX 8) serving read from @<rev>/data + zconn(s) for historical state
+//
+//
 // (*) see notes.txt -> "Notes on OS pagecache control"
 // (+) see notes.txt -> "Invalidations to wcfs clients are delayed until block access"
 // (~) see notes.txt -> "Changing mmapping while under pagefault is possible"
 // (^) see notes.txt -> "Client cannot be ptraced while under pagefault"
 // (%) no need to keep track of ZData - ZBlk1 is always marked as changed on blk data change.
 //
-// XXX 8) serving read from @<rev>/data + zconn(s) for historical state
-//
 // XXX For every ZODB connection a dedicated read-only transaction is maintained.
 
 import (
@@ -418,37 +419,39 @@ type Root struct {
 	// ZODB connections for @<rev>/
 	zrevMu  sync.Mutex
 	zrevTab map[zodb.Tid]*ZConn
+
+	// XXX include?
+	// // {} rev -> @<rev>/
+	// mu     sync.Mutex
+	// revTab map[zodb.Tid]*Rev
 }
 
-// /bigfile/	- served by BigFileRoot.
-type BigFileRoot struct {
+// /(head|<rev>)/			- served by Head.	XXX separate Rev?
+type Head struct {
 	nodefs.Node
-
-	// {} oid -> <bigfileX>/
-	mu  sync.Mutex
-	tab map[zodb.Oid]*BigFileDir
+	// bigfile, at, watch, etc - all implicitly linked to by fs
 }
 
-// /bigfile/<bigfileX>/	- served by BigFileDir.
-type BigFileDir struct {
+// /head/watch				- served by Watch.
+type Watch struct {
 	nodefs.Node
-	oid zodb.Oid // oid of ZBigFile
-
-	// head/ is implicitly linked to by fs
 
-	// {} rev -> @<rev>/ bigfile snapshot
-	mu     sync.Mutex
-	revTab map[zodb.Tid]*BigFileRev
+	// TODO
 }
 
-// /bigfile/<bigfileX>/(head|<rev>)/	- served by BigFileRev.
-type BigFileRev struct {
+// /(head|<rev>)/bigfile/		- served by BigFileDir.
+type BigFileDir struct {
 	nodefs.Node
-	// data, at, invalidations, etc - all implicitly linked to by fs
+
+	// {} oid -> <bigfileX>
+	mu  sync.Mutex
+	tab map[zodb.Oid]*BigFile
 }
 
-// /bigfile/<bigfileX>/(head|<rev>)/*	- internally served by BigFile.
+// /(head|<rev>)/bigfile/<bigfileX>	- served by BigFile.
 type BigFile struct {
+	nodefs.Node
+
 	// this BigFile views ZODB via zconn
 	zconn	*ZConn
 
@@ -463,18 +466,9 @@ type BigFile struct {
 
 	// TODO -> δFtail
 	// lastChange	zodb.Tid // last change to whole bigfile as of .zconn.At view
-}
-
-// /bigfile/<bigfileX>/(head|<rev>)/data	- served by BigFileData.
-type BigFileData struct {
-	nodefs.Node
-
-	bigfile *BigFile
 
 	// inflight loadings of ZBigFile from ZODB.
 	// successfull load results are kept here until blkdata is put into OS pagecache.
-	//
-	// XXX -> BigFile ?
 	loadMu  sync.Mutex
 	loading map[int64]*blkLoadState // #blk -> {... blkdata}
 
@@ -524,6 +518,7 @@ func (cc *zodbCacheControl) WantEvict(obj zodb.IPersistent) bool {
 	return false
 }
 
+/*
 // zwatcher watches for ZODB changes.
 // see "4) when we receive an invalidation message from ZODB ..."
 func (r *Root) zwatcher(ctx context.Context) (err error) {
@@ -550,7 +545,7 @@ func (r *Root) zhandle1(zevent zodb.WatchEvent) {
 	defer r.zheadMu.Unlock()
 
 	//toinvalidate := map[*ZBigFile]SetI64{} // {} zfile -> set(#blk)
-	toinvalidate := map[*BigFileData]SetI64{} // {} zfile -> set(#blk)
+	toinvalidate := map[*BigFile]SetI64{} // {} zfile -> set(#blk)
 
 	// zevent = (tid^, []oid)
 	for _, oid := range zevent.Changev {
@@ -601,7 +596,7 @@ func (r *Root) zhandle1(zevent zodb.WatchEvent) {
 
 // invalidateBlk invalidates 1 file block.	XXX
 // XXX see "4.4) for all file/blk to in invalidate we do"
-func (f *BigFileData) invalidateBlk(ctx context.Context, blk int64) error {
+func (f *BigFile) invalidateBlk(ctx context.Context, blk int64) error {
 	fsconn := f.root().fsconn
 	off := blk*blksize
 
@@ -630,20 +625,19 @@ func (f *BigFileData) invalidateBlk(ctx context.Context, blk int64) error {
 
 	panic("TODO")
 }
+*/
 
 // ----------------------------------------
 
-// /bigfile -> Mkdir receives client request to create /bigfile/<bigfileX>.
-//
-// It creates <bigfileX>/head/* along the way.
-func (bfroot *BigFileRoot) Mkdir(name string, mode uint32, fctx *fuse.Context) (*nodefs.Inode, fuse.Status) {
-	inode, err := bfroot.mkdir(name, fctx) // XXX ok to ignore mode?
+// /(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) {
+	inode, err := bfdir.lookup(out, name, fctx)	// XXX reorder out?
 	return inode, err2LogStatus(err)
 
 }
 
-func (bfroot *BigFileRoot) mkdir(name string, fctx *fuse.Context) (_ *nodefs.Inode, err error) {
-	defer xerr.Contextf(&err, "/bigfile: mkdir %q", name)
+func (bfdir *BigFileDir) lookup(out *fuse.Attr, name string, fctx *fuse.Context) (_ *nodefs.Inode, err error) {
+	defer xerr.Contextf(&err, "/bigfile: lookup %q", name)
 
 	oid, err := zodb.ParseOid(name)
 	if err != nil {
@@ -651,139 +645,100 @@ func (bfroot *BigFileRoot) mkdir(name string, fctx *fuse.Context) (_ *nodefs.Ino
 	}
 
 	// check to see if dir(oid) is already there
-	bfroot.mu.Lock()
-	_, already := bfroot.tab[oid]
-	bfroot.mu.Unlock()
+	bfdir.mu.Lock()
+	f, already := bfdir.tab[oid]
+	bfdir.mu.Unlock()
 
 	if already {
-		return nil, syscall.EEXIST
+		// XXX fill out
+		return f.Inode(), nil
 	}
 
-	// not there - without bfroot lock proceed to open BigFile from ZODB
-	bf, err := bigopen(asctx(fctx), groot.zhead, oid)
+	// not there - without bfdir lock proceed to open BigFile from ZODB
+	f, err = bigopen(asctx(fctx), groot.zhead, oid)	// XXX zhead -> head|rev.zconn
 	if err != nil {
 		return nil, err
 	}
-	defer func() {
-		if err != nil {
-			bf.Close()
-		}
-	}()
 
-	// relock bfroot and either mkdir or EEXIST if the directory was maybe
-	// simultanously created while we were not holding bfroot.mu
-	bfroot.mu.Lock()
-	_, already = bfroot.tab[oid]
+	// 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]
 	if already {
-		bfroot.mu.Unlock()
-		return nil, syscall.EEXIST
-	}
-
-	bfdir := &BigFileDir{
-		Node:   nodefs.NewDefaultNode(),
-		oid:    oid,
-		revTab: make(map[zodb.Tid]*BigFileRev),
-	}
-
-	bfhead := &BigFileRev{
-		Node: nodefs.NewDefaultNode(),
-	}
-
-	bfdata := &BigFileData{
-		Node:    nodefs.NewDefaultNode(),
-		bigfile: bf,
-		loading: make(map[int64]*blkLoadState),
+		bfdir.mu.Unlock()
+		f.Close()
+		return f2.Inode(), nil	// XXX fill out
 	}
 
-	bfroot.tab[oid] = bfdir
-	bfroot.mu.Unlock()
+	bfdir.tab[oid] = f
+	bfdir.mu.Unlock()
 
-	// mkdir takes filesystem treeLock - do it outside bfroot.mu
-	mkdir(bfroot, name, bfdir)
-	mkdir(bfdir, "head", bfhead)
-	mkfile(bfhead, "data", bfdata)
-	mkfile(bfhead, "at", NewSmallFile(bf.readAt))	// TODO mtime(at) = tidtime(at)
-	// XXX mkfile(bh, "invalidations", bh.inv)
+	// mkfile takes filesystem treeLock - do it outside bfdir.mu
+	mkfile(bfdir, name, f)
 
-	return bfdir.Inode(), nil
+	// XXX fill out
+	return f.Inode(), nil
 }
 
-// XXX do we need to support rmdir? (probably no)
+// XXX do we need to support unlink? (probably no)
 
-// /bigfile/<bigfileX> -> Mkdir receives client request to create @<tid>/.
-func (bfdir *BigFileDir) Mkdir(name string, mode uint32, fctx *fuse.Context) (*nodefs.Inode, fuse.Status) {
-	inode, err := bfdir.mkdir(name, fctx) // XXX ok to ignore mode?
+// / -> Mkdir receives client request to create @<rev>/.
+func (root *Root) Mkdir(name string, mode uint32, fctx *fuse.Context) (*nodefs.Inode, fuse.Status) {
+	inode, err := root.mkdir(name, fctx) // XXX ok to ignore mode?
 	return inode, err2LogStatus(err)
 }
 
-func (bfdir *BigFileDir) mkdir(name string, fctx *fuse.Context) (_ *nodefs.Inode, err error) {
-	defer xerr.Contextf(&err, "/bigfile/%s: mkdir %q", bfdir.oid, name)
+func (root *Root) mkdir(name string, fctx *fuse.Context) (_ *nodefs.Inode, err error) {
+	defer xerr.Contextf(&err, "/: mkdir %q", name)
 
-	var tid zodb.Tid
+	var rev zodb.Tid
 	ok := false
 
 	if strings.HasPrefix(name, "@") {
-		tid, err = zodb.ParseTid(name[1:])
+		rev, err = zodb.ParseTid(name[1:])
 		ok = (err == nil)
 	}
 	if !ok {
-		return nil, eINVALf("not @tid")
+		return nil, eINVALf("not @rev")
 	}
 
-	// check to see if dir(tid) is already there
-	bfdir.mu.Lock()
-	_, already := bfdir.revTab[tid]
-	bfdir.mu.Unlock()
+	// check to see if dir(rev) is already there
+	root.zrevMu.Lock()
+	_, already := root.zrevTab[rev]
+	root.zrevMu.Unlock()
 
 	if already {
 		return nil, syscall.EEXIST
 	}
 
-	// not there - without bfdir lock proceed to open BigFile @tid view of ZODB
+	// not there - without zrevMu lock proceed to open @rev view of ZODB
 	ctx := asctx(fctx)
-	zconnRev, err := groot.zopenAt(ctx, tid)
+	zconnRev, err := groot.zopenAt(ctx, rev)
 	if err != nil {
 		return nil, err
 	}
-	defer zconnRev.Release()
+	defer zconnRev.Release()	// XXX ok?
 
-	bf, err := bigopen(ctx, zconnRev, bfdir.oid)
-	if err != nil {
-		return nil, err
-	}
-	defer func() {
-		if err != nil {
-			bf.Close()
-		}
-	}()
-
-	// relock bfdir and either mkdir or EEXIST if the directory was maybe
-	// simultanously created while we were not holding bfroot.mu
-	bfdir.mu.Lock()
-	_, already = bfdir.revTab[tid]
+	// relock root and either mkdir or EEXIST if the directory was maybe
+	// simultanously created while we were not holding zrevMu.
+	root.zrevMu.Lock()
+	_, already = root.zrevTab[rev]
 	if already {
-		bfdir.mu.Unlock()
+		root.zrevMu.Unlock()
 		return nil, syscall.EEXIST
 	}
 
-	bfrev := &BigFileRev{
+	revDir := &Head{	// XXX -> Rev ?
 		Node: nodefs.NewDefaultNode(),
 	}
 
-	revdata := &BigFileData{
-		Node:    nodefs.NewDefaultNode(),
-		bigfile: bf,
-		loading: make(map[int64]*blkLoadState),
-	}
+	root.zrevTab[rev] = zconnRev
+	root.zrevMu.Unlock()
 
-	bfdir.revTab[tid] = bfrev
-	bfdir.mu.Unlock()
-
-	// mkdir takes filesystem treeLock - do it outside bfroot.mu
-	mkdir(bfdir, name, bfrev)
-	mkfile(bfrev, "data", revdata)
+	// mkdir takes filesystem treeLock - do it outside zrevMu.
+	mkdir(root, name, revDir)
 
-	return bfrev.Inode(), nil
+	return revDir.Inode(), nil
 }
 
 
@@ -844,30 +799,28 @@ func bigopen(ctx context.Context, zconn *ZConn, oid zodb.Oid) (_ *BigFile, err e
 }
 
 // Close release all resources of BigFile.
-func (bf *BigFile) Close() error {
-	bf.zbf.PDeactivate()
-	bf.zbf = nil
+func (f *BigFile) Close() error {
+	f.zbf.PDeactivate()
+	f.zbf = nil
 
-	bf.zconn.Release()
-	bf.zconn = nil
+	f.zconn.Release()
+	f.zconn = nil
 
 	return nil
 }
 
-// /bigfile/<bigfileX>/head/data -> Getattr serves stat.
-func (bfdata *BigFileData) GetAttr(out *fuse.Attr, _ nodefs.File, fctx *fuse.Context) fuse.Status {
+// /(head|<rev>)/bigfile/<bigfileX> -> Getattr serves stat.
+func (f *BigFile) GetAttr(out *fuse.Attr, _ nodefs.File, fctx *fuse.Context) fuse.Status {
 	// XXX locking
 
-	bf := bfdata.bigfile
-
 	out.Mode = fuse.S_IFREG | 0444
-	out.Size = uint64(bf.zbfSize)
+	out.Size = uint64(f.zbfSize)
 	// .Blocks
 	// .Blksize
 
 	// FIXME lastChange should cover all bigfile data, not only ZBigFile itself
-	//mtime := &bfdata.lastChange.Time().Time
-	lastChange := bf.zbf.PSerial()
+	//mtime := &f.lastChange.Time().Time
+	lastChange := f.zbf.PSerial()
 
 	mtime := lastChange.Time().Time
 	out.SetTimes(/*atime=*/nil, /*mtime=*/&mtime, /*ctime=*/&mtime)
@@ -876,17 +829,16 @@ func (bfdata *BigFileData) GetAttr(out *fuse.Attr, _ nodefs.File, fctx *fuse.Con
 }
 
 
-// /bigfile/<bigfileX>/head/data -> Read serves reading bigfile data.
-func (bfdata *BigFileData) Read(_ nodefs.File, dest []byte, off int64, fctx *fuse.Context) (fuse.ReadResult, fuse.Status) {
+// /(head|<rev>)/bigfile/<bigfileX> -> Read serves reading bigfile data.
+func (f *BigFile) Read(_ nodefs.File, dest []byte, off int64, fctx *fuse.Context) (fuse.ReadResult, fuse.Status) {
 	// XXX locking
 
-	bf := bfdata.bigfile
-	zbf := bf.zbf
+	zbf := f.zbf
 
 	// cap read request to file size
 	end := off + int64(len(dest))		// XXX overflow?
-	if end > bf.zbfSize {
-		end = bf.zbfSize
+	if end > f.zbfSize {
+		end = f.zbfSize
 	}
 	if end <= off {
 		// XXX off >= size -> EINVAL? (but when size=0 kernel issues e.g. [0 +4K) read)
@@ -903,7 +855,7 @@ func (bfdata *BigFileData) Read(_ nodefs.File, dest []byte, off int64, fctx *fus
 	dest = make([]byte, aend - aoff) // ~> [aoff:aend) in file
 
 	// XXX better ctx = transaction.PutIntoContext(ctx, txn)
-	ctx, cancel := xcontext.Merge(asctx(fctx), bf.zconn.txnCtx)
+	ctx, cancel := xcontext.Merge(asctx(fctx), f.zconn.txnCtx)
 	defer cancel()
 
 	// read/load all block(s) in parallel
@@ -914,7 +866,7 @@ func (bfdata *BigFileData) Read(_ nodefs.File, dest []byte, off int64, fctx *fus
 		wg.Go(func() error {
 			δ := blkoff-aoff // blk position in dest
 			//log.Infof("readBlk #%d dest[%d:+%d]", blk, δ, zbf.blksize)
-			return bfdata.readBlk(ctx, blk, dest[δ:δ+zbf.blksize])
+			return f.readBlk(ctx, blk, dest[δ:δ+zbf.blksize])
 		})
 	}
 
@@ -929,23 +881,23 @@ func (bfdata *BigFileData) Read(_ nodefs.File, dest []byte, off int64, fctx *fus
 
 // readBlk serves Read to read 1 ZBlk #blk into destination buffer.
 //
-// see "6) when we receive a FUSE read(#blk) request ..." in overview.
+// see "7) when we receive a FUSE read(#blk) request ..." in overview.
 //
 // len(dest) == blksize.
-func (bfdata *BigFileData) readBlk(ctx context.Context, blk int64, dest []byte) error {
+func (f *BigFile) readBlk(ctx context.Context, blk int64, dest []byte) error {
 	// XXX errctx?
 	// XXX locking
 
 	// check if someone else is already loading this block
-	bfdata.loadMu.Lock()
-	loading, already := bfdata.loading[blk]
+	f.loadMu.Lock()
+	loading, already := f.loading[blk]
 	if !already {
 		loading = &blkLoadState{
 			ready:   make(chan struct{}),
 		}
-		bfdata.loading[blk] = loading
+		f.loading[blk] = loading
 	}
-	bfdata.loadMu.Unlock()
+	f.loadMu.Unlock()
 
 	// if it is already loading - just wait for it
 	if already {
@@ -963,14 +915,14 @@ func (bfdata *BigFileData) readBlk(ctx context.Context, blk int64, dest []byte)
 
 	// noone was loading - we became reponsible to load this block
 
-	zbf := bfdata.bigfile.zbf
+	zbf := f.zbf
 	blkdata, err := zbf.LoadBlk(ctx, blk)	// XXX -> +blkrevmax1
 	loading.blkdata = blkdata
 	loading.err = err
 	close(loading.ready)
 
 	// XXX before loading.ready?
-	blkrevmax2, _ := bfdata.bigfile.δFtail.LastRevOf(blk, zbf.PJar().At())
+	blkrevmax2, _ := f.δFtail.LastRevOf(blk, zbf.PJar().At())
 	//revmax := min(blkrevmax1, blkrevmax2)
 	revmax := blkrevmax2
 	_ = revmax
@@ -979,7 +931,7 @@ func (bfdata *BigFileData) readBlk(ctx context.Context, blk int64, dest []byte)
 	// XXX remmapping
 	// XXX -> own func?
 	// XXX locking
-	for _, mapping := range bfdata.mappings {
+	for _, mapping := range f.mappings {
 		if revmax <= mapping.at || !mapping.blkrange.in(blk) {
 			continue // do nothing
 		}
@@ -1001,9 +953,9 @@ func (bfdata *BigFileData) readBlk(ctx context.Context, blk int64, dest []byte)
 
 	// data loaded with error - cleanup .loading
 	if loading.err != nil {
-		bfdata.loadMu.Lock()
-		delete(bfdata.loading, blk)
-		bfdata.loadMu.Unlock()
+		f.loadMu.Lock()
+		delete(f.loading, blk)
+		f.loadMu.Unlock()
 		return err
 	}
 
@@ -1028,11 +980,11 @@ func (bfdata *BigFileData) readBlk(ctx context.Context, blk int64, dest []byte)
 		// XXX locking - invalidation must make sure this workers are finished.
 
 		// XXX if direct-io: don't touch pagecache
-		st := gfsconn.FileNotifyStoreCache(bfdata.Inode(), blk*zbf.blksize, blkdata)
+		st := gfsconn.FileNotifyStoreCache(f.Inode(), blk*zbf.blksize, blkdata)
 
-		bfdata.loadMu.Lock()
-		delete(bfdata.loading, blk)
-		bfdata.loadMu.Unlock()
+		f.loadMu.Lock()
+		delete(f.loading, blk)
+		f.loadMu.Unlock()
 
 		if st == fuse.OK {
 			return
@@ -1137,9 +1089,8 @@ func main() {
 
 	// add entries to /
 	mkfile(root, ".wcfs", NewStaticFile([]byte(zurl)))
-	mkdir(root, "bigfile", &BigFileRoot{
+	mkdir(root, "head", &Head{
 		Node:  nodefs.NewDefaultNode(),
-		tab:   make(map[zodb.Oid]*BigFileDir),
 	})
 
 	// TODO handle autoexit