1 files changed, 82 insertions, 37 deletions

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 784cde4..9ebeaa6 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -327,19 +327,68 @@ static void queue_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rqmode)
  * Basic operations on rsb's and lkb's
  */
 
-static struct dlm_rsb *create_rsb(struct dlm_ls *ls, char *name, int len)
+static int pre_rsb_struct(struct dlm_ls *ls)
+{
+	struct dlm_rsb *r1, *r2;
+	int count = 0;
+
+	spin_lock(&ls->ls_new_rsb_spin);
+	if (ls->ls_new_rsb_count > dlm_config.ci_new_rsb_count / 2) {
+		spin_unlock(&ls->ls_new_rsb_spin);
+		return 0;
+	}
+	spin_unlock(&ls->ls_new_rsb_spin);
+
+	r1 = dlm_allocate_rsb(ls);
+	r2 = dlm_allocate_rsb(ls);
+
+	spin_lock(&ls->ls_new_rsb_spin);
+	if (r1) {
+		list_add(&r1->res_hashchain, &ls->ls_new_rsb);
+		ls->ls_new_rsb_count++;
+	}
+	if (r2) {
+		list_add(&r2->res_hashchain, &ls->ls_new_rsb);
+		ls->ls_new_rsb_count++;
+	}
+	count = ls->ls_new_rsb_count;
+	spin_unlock(&ls->ls_new_rsb_spin);
+
+	if (!count)
+		return -ENOMEM;
+	return 0;
+}
+
+/* If ls->ls_new_rsb is empty, return -EAGAIN, so the caller can
+   unlock any spinlocks, go back and call pre_rsb_struct again.
+   Otherwise, take an rsb off the list and return it. */
+
+static int get_rsb_struct(struct dlm_ls *ls, char *name, int len,
+			  struct dlm_rsb **r_ret)
 {
 	struct dlm_rsb *r;
+	int count;
 
-	r = dlm_allocate_rsb(ls, len);
-	if (!r)
-		return NULL;
+	spin_lock(&ls->ls_new_rsb_spin);
+	if (list_empty(&ls->ls_new_rsb)) {
+		count = ls->ls_new_rsb_count;
+		spin_unlock(&ls->ls_new_rsb_spin);
+		log_debug(ls, "find_rsb retry %d %d %s",
+			  count, dlm_config.ci_new_rsb_count, name);
+		return -EAGAIN;
+	}
+
+	r = list_first_entry(&ls->ls_new_rsb, struct dlm_rsb, res_hashchain);
+	list_del(&r->res_hashchain);
+	ls->ls_new_rsb_count--;
+	spin_unlock(&ls->ls_new_rsb_spin);
 
 	r->res_ls = ls;
 	r->res_length = len;
 	memcpy(r->res_name, name, len);
 	mutex_init(&r->res_mutex);
 
+	INIT_LIST_HEAD(&r->res_hashchain);
 	INIT_LIST_HEAD(&r->res_lookup);
 	INIT_LIST_HEAD(&r->res_grantqueue);
 	INIT_LIST_HEAD(&r->res_convertqueue);
@@ -347,7 +396,8 @@ static struct dlm_rsb *create_rsb(struct dlm_ls *ls, char *name, int len)
 	INIT_LIST_HEAD(&r->res_root_list);
 	INIT_LIST_HEAD(&r->res_recover_list);
 
-	return r;
+	*r_ret = r;
+	return 0;
 }
 
 static int search_rsb_list(struct list_head *head, char *name, int len,
@@ -405,16 +455,6 @@ static int _search_rsb(struct dlm_ls *ls, char *name, int len, int b,
 	return error;
 }
 
-static int search_rsb(struct dlm_ls *ls, char *name, int len, int b,
-		      unsigned int flags, struct dlm_rsb **r_ret)
-{
-	int error;
-	spin_lock(&ls->ls_rsbtbl[b].lock);
-	error = _search_rsb(ls, name, len, b, flags, r_ret);
-	spin_unlock(&ls->ls_rsbtbl[b].lock);
-	return error;
-}
-
 /*
  * Find rsb in rsbtbl and potentially create/add one
  *
@@ -432,35 +472,48 @@ static int search_rsb(struct dlm_ls *ls, char *name, int len, int b,
 static int find_rsb(struct dlm_ls *ls, char *name, int namelen,
 		    unsigned int flags, struct dlm_rsb **r_ret)
 {
-	struct dlm_rsb *r = NULL, *tmp;
+	struct dlm_rsb *r = NULL;
 	uint32_t hash, bucket;
-	int error = -EINVAL;
+	int error;
 
-	if (namelen > DLM_RESNAME_MAXLEN)
+	if (namelen > DLM_RESNAME_MAXLEN) {
+		error = -EINVAL;
 		goto out;
+	}
 
 	if (dlm_no_directory(ls))
 		flags |= R_CREATE;
 
-	error = 0;
 	hash = jhash(name, namelen, 0);
 	bucket = hash & (ls->ls_rsbtbl_size - 1);
 
-	error = search_rsb(ls, name, namelen, bucket, flags, &r);
+ retry:
+	if (flags & R_CREATE) {
+		error = pre_rsb_struct(ls);
+		if (error < 0)
+			goto out;
+	}
+
+	spin_lock(&ls->ls_rsbtbl[bucket].lock);
+
+	error = _search_rsb(ls, name, namelen, bucket, flags, &r);
 	if (!error)
-		goto out;
+		goto out_unlock;
 
 	if (error == -EBADR && !(flags & R_CREATE))
-		goto out;
+		goto out_unlock;
 
 	/* the rsb was found but wasn't a master copy */
 	if (error == -ENOTBLK)
-		goto out;
+		goto out_unlock;
 
-	error = -ENOMEM;
-	r = create_rsb(ls, name, namelen);
-	if (!r)
-		goto out;
+	error = get_rsb_struct(ls, name, namelen, &r);
+	if (error == -EAGAIN) {
+		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
+		goto retry;
+	}
+	if (error)
+		goto out_unlock;
 
 	r->res_hash = hash;
 	r->res_bucket = bucket;
@@ -474,18 +527,10 @@ static int find_rsb(struct dlm_ls *ls, char *name, int namelen,
 			nodeid = 0;
 		r->res_nodeid = nodeid;
 	}
-
-	spin_lock(&ls->ls_rsbtbl[bucket].lock);
-	error = _search_rsb(ls, name, namelen, bucket, 0, &tmp);
-	if (!error) {
-		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
-		dlm_free_rsb(r);
-		r = tmp;
-		goto out;
-	}
 	list_add(&r->res_hashchain, &ls->ls_rsbtbl[bucket].list);
-	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
 	error = 0;
+ out_unlock:
+	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
  out:
 	*r_ret = r;
 	return error;