exportfs: make struct export_operations const

Now that nfsd has stopped writing to the find_exported_dentry member we an
mark the export_operations const

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>
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index e68f027..3524653 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -16,7 +16,7 @@
 static int exportfs_get_name(struct dentry *dir, char *name,
 		struct dentry *child)
 {
-	struct export_operations *nop = dir->d_sb->s_export_op;
+	const struct export_operations *nop = dir->d_sb->s_export_op;
 
 	if (nop->get_name)
 		return nop->get_name(dir, name, child);
@@ -333,7 +333,7 @@
 int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len,
 		int connectable)
 {
- 	struct export_operations *nop = dentry->d_sb->s_export_op;
+	const struct export_operations *nop = dentry->d_sb->s_export_op;
 	int error;
 
 	if (nop->encode_fh)
@@ -349,7 +349,7 @@
 		int fh_len, int fileid_type,
 		int (*acceptable)(void *, struct dentry *), void *context)
 {
-	struct export_operations *nop = mnt->mnt_sb->s_export_op;
+	const struct export_operations *nop = mnt->mnt_sb->s_export_op;
 	struct dentry *result, *alias;
 	int err;