fs: take the ACL checks to common code

Replace the ->check_acl method with a ->get_acl method that simply reads an
ACL from disk after having a cache miss.  This means we can replace the ACL
checking boilerplate code with a single implementation in namei.c.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ext3/file.c b/fs/ext3/file.c
index f55df0e..2be5b99 100644
--- a/fs/ext3/file.c
+++ b/fs/ext3/file.c
@@ -79,7 +79,7 @@
 	.listxattr	= ext3_listxattr,
 	.removexattr	= generic_removexattr,
 #endif
-	.check_acl	= ext3_check_acl,
+	.get_acl	= ext3_get_acl,
 	.fiemap		= ext3_fiemap,
 };