fusefrontend: -sharedstorage: present stable inode numbers

Use the Gen field (inode generation) to distinguish hard links
while passing the real inode numbers to userspace.

Fixes https://github.com/rfjakob/gocryptfs/issues/584

1 files changed, 7 insertions, 6 deletions

diff --git a/internal/fusefrontend/root_node.go b/internal/fusefrontend/root_node.go
index c82078d..46bee4a 100644
--- a/internal/fusefrontend/root_node.go
+++ b/internal/fusefrontend/root_node.go
@@ -50,7 +50,13 @@ type RootNode struct {
 	dirCache dirCache
 	// inoMap translates inode numbers from different devices to unique inode
 	// numbers.
-	inoMap inomap.TranslateStater
+	inoMap *inomap.InoMap
+	// gen is the node generation numbers. Normally, it is always set to 1,
+	// but -sharestorage uses an incrementing counter for new nodes.
+	// This makes each directory entry unique (even hard links),
+	// makes go-fuse hand out separate FUSE Node IDs for each, and prevents
+	// bizarre problems when inode numbers are reused behind our back.
+	gen uint64
 }
 
 func NewRootNode(args Args, c *contentenc.ContentEnc, n *nametransform.NameTransform) *RootNode {
@@ -71,11 +77,6 @@ func NewRootNode(args Args, c *contentenc.ContentEnc, n *nametransform.NameTrans
 		inoMap:        inomap.New(),
 		dirCache:      dirCache{ivLen: ivLen},
 	}
-	// In `-sharedstorage` mode we always set the inode number to zero.
-	// This makes go-fuse generate a new inode number for each lookup.
-	if args.SharedStorage {
-		rn.inoMap = &inomap.TranslateStatZero{}
-	}
 	return rn
 }