5.3.2.1.17. VFS Mount Structure
struct vfsmount {
  struct list_head mnt_hash;

  struct vfsmount *mnt_parent;    /* fs we are mounted on */

  struct dentry *mnt_mountpoint;  /* dentry of mountpoint */
  struct dentry *mnt_root;        /* root of the mounted tree */

  struct super_block *mnt_sb;     /* pointer to superblock */

  struct list_head mnt_mounts;    /* list of children, anchored here */
  struct list_head mnt_child;     /* and going through their mnt_child */

  atomic_t mnt_count;
  int mnt_flags;
  int mnt_expiry_mark;            /* true if marked for expiry */
  char *mnt_devname;              /* Name of device e.g. /dev/dsk/hda1 */

  struct list_head mnt_list;
  struct list_head mnt_fslink;    /* link in fs-specific expiry list */

  struct namespace *mnt_namespace; /* containing namespace */
};