dlm: keep cached master rsbs during recovery

To prevent the master of an rsb from changing rapidly, an unused rsb is kept
on the "toss list" for a period of time to be reused.  The toss list was
being cleared completely for each recovery, which is unnecessary.  Much of
the benefit of the toss list can be maintained if nodes keep rsb's in their
toss list that they are the master of.  These rsb's need to be included
when the resource directory is rebuilt during recovery.

Signed-off-by: David Teigland <teigland@redhat.com>

1 files changed, 32 insertions, 34 deletions

diff --git a/fs/dlm/dir.c b/fs/dlm/dir.c
index 600bb1d..ff97ba9 100644
--- a/fs/dlm/dir.c
+++ b/fs/dlm/dir.c
@@ -329,49 +329,47 @@ int dlm_dir_lookup(struct dlm_ls *ls, int nodeid, char *name, int namelen,
 	return get_entry(ls, nodeid, name, namelen, r_nodeid);
 }
 
-/* Copy the names of master rsb's into the buffer provided.
-   Only select names whose dir node is the given nodeid. */
+static struct dlm_rsb *find_rsb_root(struct dlm_ls *ls, char *name, int len)
+{
+	struct dlm_rsb *r;
+
+	down_read(&ls->ls_root_sem);
+	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
+		if (len == r->res_length && !memcmp(name, r->res_name, len)) {
+			up_read(&ls->ls_root_sem);
+			return r;
+		}
+	}
+	up_read(&ls->ls_root_sem);
+	return NULL;
+}
+
+/* Find the rsb where we left off (or start again), then send rsb names
+   for rsb's we're master of and whose directory node matches the requesting
+   node.  inbuf is the rsb name last sent, inlen is the name's length */
 
 void dlm_copy_master_names(struct dlm_ls *ls, char *inbuf, int inlen,
  			   char *outbuf, int outlen, int nodeid)
 {
 	struct list_head *list;
-	struct dlm_rsb *start_r = NULL, *r = NULL;
-	int offset = 0, start_namelen, error, dir_nodeid;
-	char *start_name;
+	struct dlm_rsb *r;
+	int offset = 0, dir_nodeid;
 	uint16_t be_namelen;
 
-	/*
-	 * Find the rsb where we left off (or start again)
-	 */
-
-	start_namelen = inlen;
-	start_name = inbuf;
-
-	if (start_namelen > 1) {
-		/*
-		 * We could also use a find_rsb_root() function here that
-		 * searched the ls_root_list.
-		 */
-		error = dlm_find_rsb(ls, start_name, start_namelen, R_MASTER,
-				     &start_r);
-		DLM_ASSERT(!error && start_r,
-			   printk("error %d\n", error););
-		DLM_ASSERT(!list_empty(&start_r->res_root_list),
-			   dlm_print_rsb(start_r););
-		dlm_put_rsb(start_r);
-	}
-
-	/*
-	 * Send rsb names for rsb's we're master of and whose directory node
-	 * matches the requesting node.
-	 */
-
 	down_read(&ls->ls_root_sem);
-	if (start_r)
-		list = start_r->res_root_list.next;
-	else
+
+	if (inlen > 1) {
+		r = find_rsb_root(ls, inbuf, inlen);
+		if (!r) {
+			inbuf[inlen - 1] = '\0';
+			log_error(ls, "copy_master_names from %d start %d %s",
+				  nodeid, inlen, inbuf);
+			goto out;
+		}
+		list = r->res_root_list.next;
+	} else {
 		list = ls->ls_root_list.next;
+	}
 
 	for (offset = 0; list != &ls->ls_root_list; list = list->next) {
 		r = list_entry(list, struct dlm_rsb, res_root_list);