FS-Cache: Make kAFS use FS-Cache

The attached patch makes the kAFS filesystem in fs/afs/ use FS-Cache, and
through it any attached caches.  The kAFS filesystem will use caching
automatically if it's available.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index bb47217..c048f06 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -61,6 +61,11 @@
 		return -EBADMSG;
 	}
 
+#ifdef CONFIG_AFS_FSCACHE
+	if (vnode->status.size != inode->i_size)
+		fscache_attr_changed(vnode->cache);
+#endif
+
 	inode->i_nlink		= vnode->status.nlink;
 	inode->i_uid		= vnode->status.owner;
 	inode->i_gid		= 0;
@@ -149,15 +154,6 @@
 		return inode;
 	}
 
-#ifdef AFS_CACHING_SUPPORT
-	/* set up caching before reading the status, as fetch-status reads the
-	 * first page of symlinks to see if they're really mntpts */
-	cachefs_acquire_cookie(vnode->volume->cache,
-			       NULL,
-			       vnode,
-			       &vnode->cache);
-#endif
-
 	if (!status) {
 		/* it's a remotely extant inode */
 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
@@ -183,6 +179,15 @@
 		}
 	}
 
+	/* set up caching before mapping the status, as map-status reads the
+	 * first page of symlinks to see if they're really mountpoints */
+	inode->i_size = vnode->status.size;
+#ifdef CONFIG_AFS_FSCACHE
+	vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
+					      &afs_vnode_cache_index_def,
+					      vnode);
+#endif
+
 	ret = afs_inode_map_status(vnode, key);
 	if (ret < 0)
 		goto bad_inode;
@@ -196,6 +201,10 @@
 
 	/* failure */
 bad_inode:
+#ifdef CONFIG_AFS_FSCACHE
+	fscache_relinquish_cookie(vnode->cache, 0);
+	vnode->cache = NULL;
+#endif
 	iget_failed(inode);
 	_leave(" = %d [bad]", ret);
 	return ERR_PTR(ret);
@@ -340,8 +349,8 @@
 	ASSERT(list_empty(&vnode->writebacks));
 	ASSERT(!vnode->cb_promised);
 
-#ifdef AFS_CACHING_SUPPORT
-	cachefs_relinquish_cookie(vnode->cache, 0);
+#ifdef CONFIG_AFS_FSCACHE
+	fscache_relinquish_cookie(vnode->cache, 0);
 	vnode->cache = NULL;
 #endif