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.TH "FIND_EXPORTED_DENTRY" "" "06 October 2005" "" ""

.SH NAME
find_exported_dentry \- helper routine to implement export_operations->decode_fh
.SH SYNOPSIS
"SYNOPSIS"
.sp
\fB
.sp
struct dentry * find_exported_dentry  (struct super_block * \fIsb\fB, void * \fIobj\fB, void * \fIparent\fB, int (*\fIacceptable\fB)
void *context, struct dentry *de, void * \fIcontext\fB);
\fR
.SH "ARGUMENTS"
.TP
\fB\fIsb\fB\fR
The &super_block identifying the filesystem
.TP
\fB\fIobj\fB\fR
An opaque identifier of the object to be found - passed to
get_inode
.TP
\fB\fIparent\fB\fR
An optional opqaue identifier of the parent of the object.
.TP
\fB\fIacceptable\fB\fR
A function used to test possible &dentries to see if they are
acceptable
.TP
\fB\fIcontext\fB\fR
A parameter to \fIacceptable\fR so that it knows on what basis to
judge.
.SH "DESCRIPTION"
.PP
find_exported_dentry is the central helper routine to enable file systems
to provide the \fBdecode_fh\fR export_operation.  It's main task is to take
an &inode, find or create an appropriate &dentry structure, and possibly
splice this into the dcache in the correct place.
.PP
The \fBdecode_fh\fR operation provided by the filesystem should call
\fBfind_exported_dentry\fR with the same parameters that it received except
that instead of the file handle fragment, pointers to opaque identifiers
for the object and optionally its parent are passed.  The default decode_fh
routine passes one pointer to the start of the filehandle fragment, and
one 8 bytes into the fragment.  It is expected that most filesystems will
take this approach, though the offset to the parent identifier may well be
different.
.PP
\fBfind_exported_dentry\fR will call get_dentry to get an dentry pointer from
the file system.  If any &dentry in the d_alias list is acceptable, it will
be returned.  Otherwise \fBfind_exported_dentry\fR will attempt to splice a new
&dentry into the dcache using \fBget_name\fR and \fBget_parent\fR to find the
appropriate place.