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, 23 insertions, 2 deletions

diff --git a/fs/dlm/recover.c b/fs/dlm/recover.c
index 2f9d9a3..df075dc 100644
--- a/fs/dlm/recover.c
+++ b/fs/dlm/recover.c
@@ -731,6 +731,20 @@ int dlm_create_root_list(struct dlm_ls *ls)
 			list_add(&r->res_root_list, &ls->ls_root_list);
 			dlm_hold_rsb(r);
 		}
+
+		/* If we're using a directory, add tossed rsbs to the root
+		   list; they'll have entries created in the new directory,
+		   but no other recovery steps should do anything with them. */
+
+		if (dlm_no_directory(ls)) {
+			read_unlock(&ls->ls_rsbtbl[i].lock);
+			continue;
+		}
+
+		list_for_each_entry(r, &ls->ls_rsbtbl[i].toss, res_hashchain) {
+			list_add(&r->res_root_list, &ls->ls_root_list);
+			dlm_hold_rsb(r);
+		}
 		read_unlock(&ls->ls_rsbtbl[i].lock);
 	}
  out:
@@ -750,6 +764,11 @@ void dlm_release_root_list(struct dlm_ls *ls)
 	up_write(&ls->ls_root_sem);
 }
 
+/* If not using a directory, clear the entire toss list, there's no benefit to
+   caching the master value since it's fixed.  If we are using a dir, keep the
+   rsb's we're the master of.  Recovery will add them to the root list and from
+   there they'll be entered in the rebuilt directory. */
+
 void dlm_clear_toss_list(struct dlm_ls *ls)
 {
 	struct dlm_rsb *r, *safe;
@@ -759,8 +778,10 @@ void dlm_clear_toss_list(struct dlm_ls *ls)
 		write_lock(&ls->ls_rsbtbl[i].lock);
 		list_for_each_entry_safe(r, safe, &ls->ls_rsbtbl[i].toss,
 					 res_hashchain) {
-			list_del(&r->res_hashchain);
-			dlm_free_rsb(r);
+			if (dlm_no_directory(ls) || !is_master(r)) {
+				list_del(&r->res_hashchain);
+				dlm_free_rsb(r);
+			}
 		}
 		write_unlock(&ls->ls_rsbtbl[i].lock);
 	}