core: remove "file name too long" limitation

* part four, prev. commit: b89781d

Signed-off-by: Alex Aizman <[email protected]>

core/lfile.go

@@ -188,12 +188,28 @@ func (lom *LOM) RenameFinalize(wfqn string) error {
 		return &errBdir{cname: lom.Cname(), err: err}
 	}
 	err := lom.RenameToMain(wfqn)
-	if err == nil {
+	switch {
+	case err == nil:
 		return nil
-	}
-	if cos.IsErrMv(err) {
+	case cos.IsErrMv(err):
+		return err
+	case cos.IsErrFntl(err):
+		// - when finalizing LOM: fixup fntl in place
+		var (
+			short = lom.ShortenFntl()
+			saved = lom.PushFntl(short)
+		)
+		err = lom.RenameToMain(wfqn)
+		if err == nil {
+			lom.md.lid = lom.md.lid.setlmfl(lmflFntl)
+			lom.SetCustomKey(cmn.OrigFntl, saved[0])
+		} else {
+			debug.Assert(!cos.IsErrFntl(err))
+			lom.PopFntl(saved)
+		}
 		return err
+	default:
+		T.FSHC(err, lom.Mountpath(), wfqn)
+		return cmn.NewErrFailedTo(T, "finalize", lom.Cname(), err)
 	}
-	T.FSHC(err, lom.Mountpath(), wfqn)
-	return cmn.NewErrFailedTo(T, "finalize", lom.Cname(), err)
 }

core/lom.go

@@ -563,6 +563,7 @@ func (lom *LOM) FromFS() error {
 	switch {
 	case os.IsNotExist(err):
 		return err
+
 	case strings.Contains(err.Error(), "not a directory") && cos.IsPathErr(err):
 		// e.g. err "stat .../aaa/111: not a directory" when there's existing ".../aaa" object
 		return fmt.Errorf("%w (object in the path?)", err)
@@ -665,20 +666,17 @@ func (lom *LOM) Unlock(exclusive bool) {
 // file name too long (0x24) ----------------------------
 //
 
-const (
-	prefixFntl = ".x"
-)
-
 func (lom *LOM) IsFntl() bool {
 	return lom.md.lid.haslmfl(lmflFntl)
 }
 
 func (lom *LOM) HasFntlPrefix() bool {
-	return strings.HasPrefix(lom.ObjName, prefixFntl)
+	return strings.HasPrefix(lom.ObjName, fs.PrefixFntl)
 }
 
 func (lom *LOM) ShortenFntl() []string {
-	noname := prefixFntl + cos.ChecksumB2S(cos.UnsafeB(lom.FQN), cos.ChecksumSHA256)
+	// (compare with fs/content Gen())
+	noname := fs.PrefixFntl + cos.ChecksumB2S(cos.UnsafeB(lom.FQN), cos.ChecksumSHA256)
 	nfqn := lom.mi.MakePathFQN(lom.Bucket(), fs.ObjectType, noname)
 
 	debug.Assert(len(nfqn) < 4096, "PATH_MAX /usr/include/limits.h", len(nfqn))

fs/content.go

@@ -40,6 +40,14 @@ const (
 	ECMetaType   = "mt"
 )
 
+// file name too long (0x24)
+const (
+	PrefixFntl = ".x"
+
+	maxLenBasename = 255
+	maxLenPath     = 4000 // ref: PATH_MAX = 4096 in /usr/include/limits.h
+)
+
 type (
 	ContentResolver interface {
 		// Generates unique base name for original one. This function may add
@@ -120,6 +128,18 @@ func (f *contentSpecMgr) Gen(parts PartsFQN, contentType, prefix string) (fqn st
 		spec    = f.m[contentType]
 		objName = spec.GenUniqueFQN(parts.ObjectName(), prefix)
 	)
+
+	// [NOTE]
+	// override caller-provided  `objName` to prevent "file name too long" errno 0x24
+	// - full pathname should be fine as (validated) bucket name <= 64
+	// - see related: core/lom and "fixup fntl"
+	if l := len(objName); l > maxLenBasename {
+		if l > maxLenPath || len(filepath.Base(objName)) > maxLenBasename {
+			nlog.Warningln("file name too long (0x24):", objName)
+			objName = PrefixFntl + cos.ChecksumB2S(cos.UnsafeB(objName), cos.ChecksumSHA256)
+		}
+	}
+
 	return parts.Mountpath().MakePathFQN(parts.Bucket(), contentType, objName)
 }