diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 1e941b3..537d38b 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1014,6 +1014,20 @@
 	return file ? fuse_fsync_common(file, de, datasync, 1) : 0;
 }
 
+static bool update_mtime(unsigned ivalid)
+{
+	/* Always update if mtime is explicitly set  */
+	if (ivalid & ATTR_MTIME_SET)
+		return true;
+
+	/* If it's an open(O_TRUNC) or an ftruncate(), don't update */
+	if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
+		return false;
+
+	/* In all other cases update */
+	return true;
+}
+
 static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg)
 {
 	unsigned ivalid = iattr->ia_valid;
@@ -1026,11 +1040,19 @@
 		arg->valid |= FATTR_GID,    arg->gid = iattr->ia_gid;
 	if (ivalid & ATTR_SIZE)
 		arg->valid |= FATTR_SIZE,   arg->size = iattr->ia_size;
-	/* You can only _set_ these together (they may change by themselves) */
-	if ((ivalid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME)) {
-		arg->valid |= FATTR_ATIME | FATTR_MTIME;
+	if (ivalid & ATTR_ATIME) {
+		arg->valid |= FATTR_ATIME;
 		arg->atime = iattr->ia_atime.tv_sec;
+		arg->atimensec = iattr->ia_atime.tv_nsec;
+		if (!(ivalid & ATTR_ATIME_SET))
+			arg->valid |= FATTR_ATIME_NOW;
+	}
+	if ((ivalid & ATTR_MTIME) && update_mtime(ivalid)) {
+		arg->valid |= FATTR_MTIME;
 		arg->mtime = iattr->ia_mtime.tv_sec;
+		arg->mtimensec = iattr->ia_mtime.tv_nsec;
+		if (!(ivalid & ATTR_MTIME_SET))
+			arg->valid |= FATTR_MTIME_NOW;
 	}
 }