URL
https://opencores.org/ocsvn/openrisc_2011-10-31/openrisc_2011-10-31/trunk
Subversion Repositories openrisc_2011-10-31
[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [doc/] [html/] [ref/] [fileio-mounting.html] - Rev 482
Go to most recent revision | Compare with Previous | Blame | View Log
<!-- Copyright (C) 2003 Red Hat, Inc. -->
<!-- This material may be distributed only subject to the terms -->
<!-- and conditions set forth in the Open Publication License, v1.0 -->
<!-- or later (the latest version is presently available at -->
<!-- http://www.opencontent.org/openpub/). -->
<!-- Distribution of the work or derivative of the work in any -->
<!-- standard (paper) book form is prohibited unless prior -->
<!-- permission is obtained from the copyright holder. -->
<HTML
><HEAD
><TITLE
>Initialization and Mounting</TITLE
><meta name="MSSmartTagsPreventParsing" content="TRUE">
<META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+
"><LINK
REL="HOME"
TITLE="eCos Reference Manual"
HREF="ecos-ref.html"><LINK
REL="UP"
TITLE="File System Support Infrastructure"
HREF="fileio.html"><LINK
REL="PREVIOUS"
TITLE="Synchronization"
HREF="fileio-synchronization.html"><LINK
REL="NEXT"
TITLE="Sockets"
HREF="fileio-sockets.html"></HEAD
><BODY
CLASS="CHAPTER"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>eCos Reference Manual</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="fileio-synchronization.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="fileio-sockets.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="CHAPTER"
><H1
><A
NAME="FILEIO-MOUNTING">Chapter 25. Initialization and Mounting</H1
><P
>As mentioned previously, mount table entries can be sourced from two
places. Static entries may be defined by using the
<TT
CLASS="LITERAL"
>MTAB_ENTRY()</TT
> macro. Such entries will be
automatically mounted on system startup. For each entry in the mount
table that has a non-null <TT
CLASS="STRUCTFIELD"
><I
>name</I
></TT
> field the
filesystem table is searched for a match with the
<TT
CLASS="STRUCTFIELD"
><I
>fsname</I
></TT
> field. If a match is found the
filesystem's <TT
CLASS="STRUCTFIELD"
><I
>mount</I
></TT
> entry is called and if
successful the mount table entry marked valid and the
<TT
CLASS="STRUCTFIELD"
><I
>fs</I
></TT
> field initialized. The
<TT
CLASS="FUNCTION"
>mount()</TT
> function is responsible for initializing
the <TT
CLASS="STRUCTFIELD"
><I
>root</I
></TT
> field.</P
><P
>The size of the mount table is defined by the configuration value
<TT
CLASS="LITERAL"
>CYGNUM_FILEIO_MTAB_MAX</TT
>. Any entries that have not
been statically defined are available for use by dynamic mounts.</P
><P
>A filesystem may be mounted dynamically by calling <TT
CLASS="FUNCTION"
>mount()</TT
>. This
function has the following prototype:</P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>int mount( const char *devname,
const char *dir,
const char *fsname);</PRE
></TD
></TR
></TABLE
><P
>The <TT
CLASS="PARAMETER"
><I
>devname</I
></TT
> argument identifies a device that
will be used by this filesystem and will be assigned to the
<TT
CLASS="STRUCTFIELD"
><I
>devname</I
></TT
> field of the mount table entry.</P
><P
>The <TT
CLASS="PARAMETER"
><I
>dir</I
></TT
> argument is the mount point name, it
will be assigned to the <TT
CLASS="STRUCTFIELD"
><I
>name</I
></TT
> field of the
mount table entry.</P
><P
>The <TT
CLASS="PARAMETER"
><I
>fsname</I
></TT
> argument is the name of the
implementing filesystem, it will be assigned to the
<TT
CLASS="STRUCTFIELD"
><I
>fsname</I
></TT
> entry of the mount table entry.</P
><P
>The process of mounting a filesystem dynamically is as follows. First
a search is made of the mount table for an entry with a NULL
<TT
CLASS="STRUCTFIELD"
><I
>name</I
></TT
> field to be used for the new mount
point. The filesystem table is then searched for an entry whose name
matches <TT
CLASS="STRUCTFIELD"
><I
>fsname</I
></TT
>. If this is successful then
the mount table entry is initialized and the filesystem's
<TT
CLASS="FUNCTION"
>mount()</TT
> operation called. If this is successful,
the mount table entry is marked valid and the
<TT
CLASS="STRUCTFIELD"
><I
>fs</I
></TT
> field initialized.</P
><P
>Unmounting a filesystem is done by the <TT
CLASS="FUNCTION"
>umount()</TT
>
function. This can unmount filesystems whether they were mounted
statically or dynamically.</P
><P
>The <TT
CLASS="FUNCTION"
>umount()</TT
> function has the following prototype:</P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>int umount( const char *name );</PRE
></TD
></TR
></TABLE
><P
>The mount table is searched for a match between the
<TT
CLASS="PARAMETER"
><I
>name</I
></TT
> argument and the entry
<TT
CLASS="STRUCTFIELD"
><I
>name</I
></TT
> field. When a match is found the
filesystem's <TT
CLASS="FUNCTION"
>umount()</TT
> operation is called and if
successful, the mount table entry is invalidated by setting its
<TT
CLASS="STRUCTFIELD"
><I
>valid</I
></TT
> field false and the
<TT
CLASS="STRUCTFIELD"
><I
>name</I
></TT
> field to NULL.</P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="fileio-synchronization.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="ecos-ref.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="fileio-sockets.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Synchronization</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="fileio.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Sockets</TD
></TR
></TABLE
></DIV
></BODY
></HTML
> Go to most recent revision | Compare with Previous | Blame | View Log