From 2d1dc3fe734a091e7d2b0ce335484be0db6c56b0 Mon Sep 17 00:00:00 2001
From: Amar Takhar <verm@darkbeer.org>
Date: Sat, 16 Jan 2016 10:28:13 -0500
Subject: Split document into seperate files by section.

---
 filesystem/mounting_and_unmounting.rst | 102 +++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 filesystem/mounting_and_unmounting.rst

(limited to 'filesystem/mounting_and_unmounting.rst')

diff --git a/filesystem/mounting_and_unmounting.rst b/filesystem/mounting_and_unmounting.rst
new file mode 100644
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+Mounting and Unmounting Filesystems
+###################################
+
+Mount Points
+============
+
+The following is the list of the characteristics of a mount point:
+
+- The mount point must be a directory. It may have files and other
+  directories under it. These files and directories will be hidden when the
+  filesystem is mounted.
+
+- The task must have read/write/execute permissions to the mount point
+  or the mount attempt will be rejected.
+
+- Only one filesystem can be mounted to a single mount point.
+
+- The Root of the mountable filesystem will be referenced by the name
+  of the mount point after the mount is complete.
+
+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:
+.. code:: c
+
+    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.
+
+Adding entries to the chain during mount
+========================================
+
+When a filesystem is mounted, its presence and location in the file
+system hierarchy is recorded in a dynamic list structure known as a chain.
+A unique rtems_filesystem_mount_table_entry_tt structure is logged for
+each filesystem that is mounted. This includes the base filesystem.
+
+Removing entries from the chain during unmount
+==============================================
+
+When a filesystem is dismounted its entry in the mount table chain is
+extracted and the memory for this entry is freed.
+
+.. COMMENT: COPYRIGHT (c) 1988-2002.
+
+.. COMMENT: On-Line Applications Research Corporation (OAR).
+
+.. COMMENT: All rights reserved.
+
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