sysfs: fix hardlink count on device_move

Update directory hardlink count when moving kobjects to a new parent.
Fixes the following problem which occurs when several devices are
moved to the same parent and then unregistered:

> ls -laF /sys/devices/css0/defunct/
> total 0
> drwxr-xr-x 4294967295 root root    0 2009-07-14 17:02 ./
> drwxr-xr-x        114 root root    0 2009-07-14 17:02 ../
> drwxr-xr-x          2 root root    0 2009-07-14 17:01 power/
> -rw-r--r--          1 root root 4096 2009-07-14 17:01 uevent
Signed-off-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

fs/sysfs/dir.c

@@ -939,8 +939,10 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
 	/* Remove from old parent's list and insert into new parent's list. */
 	sysfs_unlink_sibling(sd);
 	sysfs_get(new_parent_sd);
+	drop_nlink(old_parent->d_inode);
 	sysfs_put(sd->s_parent);
 	sd->s_parent = new_parent_sd;
+	inc_nlink(new_parent->d_inode);
 	sysfs_link_sibling(sd);
 
  out_unlock: