exportfs: update documentation

Update documentation to the current state of affairs.  Remove duplicated
method descruptions in exportfs.h and point to Documentation/filesystems/
Exporting instead.  Add a little file header comment in expfs.c describing
what's going on and mentioning Neils and my copyright [1].

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Neil Brown <neilb@suse.de>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: <linux-ext4@vger.kernel.org>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: David Chinner <dgc@sgi.com>
Cc: Timothy Shimmin <tes@sgi.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Chris Mason <mason@suse.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: "Vladimir V. Saveliev" <vs@namesys.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 24 deletions

diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index 0b4a771..51d2141 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -55,30 +55,8 @@ struct fid {
  * @get_parent:     find the parent of a given directory
  * @get_dentry:     find a dentry for the inode given a file handle sub-fragment
  *
- * Description:
- *    The export_operations structure provides a means for nfsd to communicate
- *    with a particular exported file system  - particularly enabling nfsd and
- *    the filesystem to co-operate when dealing with file handles.
- *
- *    export_operations contains two basic operation for dealing with file
- *    handles, decode_fh() and encode_fh(), and allows for some other
- *    operations to be defined which standard helper routines use to get
- *    specific information from the filesystem.
- *
- *    nfsd encodes information use to determine which filesystem a filehandle
- *    applies to in the initial part of the file handle.  The remainder, termed
- *    a file handle fragment, is controlled completely by the filesystem.  The
- *    standard helper routines assume that this fragment will contain one or
- *    two sub-fragments, one which identifies the file, and one which may be
- *    used to identify the (a) directory containing the file.
- *
- *    In some situations, nfsd needs to get a dentry which is connected into a
- *    specific part of the file tree.  To allow for this, it passes the
- *    function acceptable() together with a @context which can be used to see
- *    if the dentry is acceptable.  As there can be multiple dentrys for a
- *    given file, the filesystem should check each one for acceptability before
- *    looking for the next.  As soon as an acceptable one is found, it should
- *    be returned.
+ * See Documentation/filesystems/Exporting for details on how to use
+ * this interface correctly.
  *
  * encode_fh:
  *    @encode_fh should store in the file handle fragment @fh (using at most