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-NAME="FILEIO-SYNCHRONIZATION">Chapter 24. Synchronization</H1
-><P
->The FILEIO infrastructure provides a synchronization mechanism for
-controlling concurrent access to filesystems. This allows existing
-filesystems to be ported to eCos, even if they do not have their own
-synchronization mechanisms. It also allows new filesystems to be
-implemented easily without having to consider the synchronization
-issues.</P
-><P
->The infrastructure maintains a mutex for each entry in each of
-the main tables: filesystem table, mount table and file table. For
-each class of operation each of these mutexes may be locked before the
-corresponding filesystem operation is invoked.</P
-><P
->The synchronization protocol required by a filesystem is described
-by the <TT
-CLASS="STRUCTFIELD"
-><I
->syncmode</I
-></TT
-> field of the filesystem
-table entry. This is a combination of the following flags:</P
-><P
-></P
-><DIV
-CLASS="VARIABLELIST"
-><DL
-><DT
-><TT
-CLASS="LITERAL"
->CYG_SYNCMODE_FILE_FILESYSTEM</TT
-></DT
-><DD
-><P
->Lock the filesystem table entry mutex
-during all filesystem level operations.</P
-></DD
-><DT
-><TT
-CLASS="LITERAL"
->CYG_SYNCMODE_FILE_MOUNTPOINT</TT
-></DT
-><DD
-><P
->Lock the mount table entry mutex
-during all filesystem level operations.</P
-></DD
-><DT
-><TT
-CLASS="LITERAL"
->CYG_SYNCMODE_IO_FILE</TT
-></DT
-><DD
-><P
->Lock the file table entry mutex during all
-I/O operations.</P
-></DD
-><DT
-><TT
-CLASS="LITERAL"
->CYG_SYNCMODE_IO_FILESYSTEM</TT
-></DT
-><DD
-><P
->Lock the filesystem table entry mutex during all I/O operations.</P
-></DD
-><DT
-><TT
-CLASS="LITERAL"
->CYG_SYNCMODE_IO_MOUNTPOINT</TT
-></DT
-><DD
-><P
->Lock the mount table entry mutex during all I/O operations.</P
-></DD
-><DT
-><TT
-CLASS="LITERAL"
->CYG_SYNCMODE_SOCK_FILE</TT
-></DT
-><DD
-><P
->Lock the file table entry mutex during all socket operations.</P
-></DD
-><DT
-><TT
-CLASS="LITERAL"
->CYG_SYNCMODE_SOCK_NETSTACK</TT
-></DT
-><DD
-><P
->Lock the network stack table entry mutex during all socket operations.</P
-></DD
-><DT
-><TT
-CLASS="LITERAL"
->CYG_SYNCMODE_NONE</TT
-></DT
-><DD
-><P
->Perform no locking at all during any operations.</P
-></DD
-></DL
-></DIV
-><P
->The value of the <TT
-CLASS="STRUCTFIELD"
-><I
->syncmode</I
-></TT
-> field in the
-filesystem table entry will be copied by the infrastructure to the
-open file object after a successful <TT
-CLASS="FUNCTION"
->open()</TT
-> operation.</P
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