RTEMS 4.9.4 On-Line Library

Mount Table Chain

RTEMS Filesystem Design Guide

3.2: Mount Table Chain

The mount table chain is a dynamic list of structures that describe mounted filesystems a specific points in the filesystem hierarchy. It is initialized to an empty state during the base filesystem initialization. The mount operation will add entries to the mount table chain. The un-mount operation will remove entries from the mount table chain.

Each entry in the mount table chain is of the following type:

struct rtems_filesystem_mount_table_entry_tt
{
   Chain_Node                             Node;
   rtems_filesystem_location_info_t       mt_point_node;
   rtems_filesystem_location_info_t       mt_fs_root;
   int                                    options;
   void                                  *fs_info;

   rtems_filesystem_limits_and_options_t  pathconf_limits_and_options;

  /*
   *  When someone adds a mounted filesystem on a real device,
   *  this will need to be used.
   *
   *  The best option long term for this is probably an
   *  open file descriptor.
   */
   char                                  *dev;
};

Node: The Node is used to produce a linked list of mount table entry nodes.
mt_point_node: The mt_point_node contains all information necessary to access the directory where a filesystem is mounted onto. This element may contain memory that is allocated during a path evaluation of the filesystem containing the mountpoint directory. The generic code allows this memory to be returned by unmount when the filesystem identified by mt_fs_root is unmounted.
mt_fs_root: The mt_fs_root contains all information necessary to identify the root of the mounted filesystem. The user is never allowed access to this node by the generic code, but it is used to identify to the mounted filesystem where to start evaluation of pathnames at.
options: XXX
fs_info: The fs_info element is a location available for use by the mounted file system to identify unique things applicable to this instance of the file system. For example the IMFS uses this space to provide node identification that is unique for each instance (mounting) of the filesystem.
pathconf_limits_and_options: XXX
dev: This character string represents the device where the filesystem will reside.

RTEMS Filesystem Design Guide