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/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index ca7e252..7e46991 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -52,7 +52,7 @@
 	void (*put_link) (struct dentry *, struct nameidata *, void *);
 	void (*truncate) (struct inode *);
 	int (*permission) (struct inode *, int, unsigned int);
-	int (*check_acl)(struct inode *, int);
+	int (*get_acl)(struct inode *, int);
 	int (*setattr) (struct dentry *, struct iattr *);
 	int (*getattr) (struct vfsmount *, struct dentry *, struct kstat *);
 	int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
@@ -80,7 +80,7 @@
 truncate:	yes		(see below)
 setattr:	yes
 permission:	no (may not block if called in rcu-walk mode)
-check_acl:	no
+get_acl:	no
 getattr:	no
 setxattr:	yes
 getxattr:	no