Revert "sysfs: Kill nlink counting."

This reverts commit 524b6c5b39b931311dfe5a2f5abae2f5c9731676.

It has shown to break userspace tools, which is not acceptable.

Reported-by: Jiri Slaby <jslaby@suse.cz>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index dd3779c..2a7a3f5 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -91,6 +91,9 @@
 	struct rb_node **node = &sd->s_parent->s_dir.children.rb_node;
 	struct rb_node *parent = NULL;
 
+	if (sysfs_type(sd) == SYSFS_DIR)
+		sd->s_parent->s_dir.subdirs++;
+
 	while (*node) {
 		struct sysfs_dirent *pos;
 		int result;
@@ -123,6 +126,9 @@
  */
 static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
 {
+	if (sysfs_type(sd) == SYSFS_DIR)
+		sd->s_parent->s_dir.subdirs--;
+
 	rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
 }