[PATCH] add a file_permission helper

A few more callers of permission() just want to check for a different access
pattern on an already open file.  This patch adds a wrapper for permission()
that takes a file in preparation of per-mount read-only support and to clean
up the callers a little.  The helper is not intended for new code, everything
without the interface set in stone should use vfs_permission()

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/udf/file.c b/fs/udf/file.c
index bb40d63..01f520c 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -186,7 +186,7 @@
 {
 	int result = -EINVAL;
 
-	if ( permission(inode, MAY_READ, NULL) != 0 )
+	if ( file_permission(filp, MAY_READ) != 0 )
 	{
 		udf_debug("no permission to access inode %lu\n",
 						inode->i_ino);