ceph: remove outdated frag information

If directory fragments change, fill_inode() inserts new frags into
the fragtree, but it does not remove outdated frags from the fragtree.
This patch fixes it.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>

fs/ceph/inode.c

@@ -577,6 +577,8 @@ static int fill_inode(struct inode *inode,
 	int issued = 0, implemented;
 	struct timespec mtime, atime, ctime;
 	u32 nsplits;
+	struct ceph_inode_frag *frag;
+	struct rb_node *rb_node;
 	struct ceph_buffer *xattr_blob = NULL;
 	int err = 0;
 	int queue_trunc = 0;
@@ -751,15 +753,38 @@ static int fill_inode(struct inode *inode,
 	/* FIXME: move me up, if/when version reflects fragtree changes */
 	nsplits = le32_to_cpu(info->fragtree.nsplits);
 	mutex_lock(&ci->i_fragtree_mutex);
+	rb_node = rb_first(&ci->i_fragtree);
 	for (i = 0; i < nsplits; i++) {
 		u32 id = le32_to_cpu(info->fragtree.splits[i].frag);
-		struct ceph_inode_frag *frag = __get_or_create_frag(ci, id);
-
-		if (IS_ERR(frag))
-			continue;
+		frag = NULL;
+		while (rb_node) {
+			frag = rb_entry(rb_node, struct ceph_inode_frag, node);
+			if (ceph_frag_compare(frag->frag, id) >= 0) {
+				if (frag->frag != id)
+					frag = NULL;
+				else
+					rb_node = rb_next(rb_node);
+				break;
+			}
+			rb_node = rb_next(rb_node);
+			rb_erase(&frag->node, &ci->i_fragtree);
+			kfree(frag);
+			frag = NULL;
+		}
+		if (!frag) {
+			frag = __get_or_create_frag(ci, id);
+			if (IS_ERR(frag))
+				continue;
+		}
 		frag->split_by = le32_to_cpu(info->fragtree.splits[i].by);
 		dout(" frag %x split by %d\n", frag->frag, frag->split_by);
 	}
+	while (rb_node) {
+		frag = rb_entry(rb_node, struct ceph_inode_frag, node);
+		rb_node = rb_next(rb_node);
+		rb_erase(&frag->node, &ci->i_fragtree);
+		kfree(frag);
+	}
 	mutex_unlock(&ci->i_fragtree_mutex);
 
 	/* were we issued a capability? */