ocfs2_dlm: fix cluster-wide refcounting of lock resources
This was previously broken and migration of some locks had to be temporarily
disabled. We use a new (and backward-incompatible) set of network messages
to account for all references to a lock resources held across the cluster.
once these are all freed, the master node may then free the lock resource
memory once its local references are dropped.
Signed-off-by: Kurt Hackel <kurt.hackel@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c
index 0c822f3..620eb82 100644
--- a/fs/ocfs2/dlm/dlmthread.c
+++ b/fs/ocfs2/dlm/dlmthread.c
@@ -54,9 +54,6 @@
#include "cluster/masklog.h"
static int dlm_thread(void *data);
-static void dlm_purge_lockres_now(struct dlm_ctxt *dlm,
- struct dlm_lock_resource *lockres);
-
static void dlm_flush_asts(struct dlm_ctxt *dlm);
#define dlm_lock_is_remote(dlm, lock) ((lock)->ml.node != (dlm)->node_num)
@@ -82,14 +79,33 @@
current->state = TASK_RUNNING;
}
-
-int __dlm_lockres_unused(struct dlm_lock_resource *res)
+int __dlm_lockres_has_locks(struct dlm_lock_resource *res)
{
if (list_empty(&res->granted) &&
list_empty(&res->converting) &&
- list_empty(&res->blocked) &&
- list_empty(&res->dirty))
- return 1;
+ list_empty(&res->blocked))
+ return 0;
+ return 1;
+}
+
+/* "unused": the lockres has no locks, is not on the dirty list,
+ * has no inflight locks (in the gap between mastery and acquiring
+ * the first lock), and has no bits in its refmap.
+ * truly ready to be freed. */
+int __dlm_lockres_unused(struct dlm_lock_resource *res)
+{
+ if (!__dlm_lockres_has_locks(res) &&
+ list_empty(&res->dirty)) {
+ /* try not to scan the bitmap unless the first two
+ * conditions are already true */
+ int bit = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
+ if (bit >= O2NM_MAX_NODES) {
+ /* since the bit for dlm->node_num is not
+ * set, inflight_locks better be zero */
+ BUG_ON(res->inflight_locks != 0);
+ return 1;
+ }
+ }
return 0;
}
@@ -106,46 +122,21 @@
assert_spin_locked(&res->spinlock);
if (__dlm_lockres_unused(res)){
- /* For now, just keep any resource we master */
- if (res->owner == dlm->node_num)
- {
- if (!list_empty(&res->purge)) {
- mlog(0, "we master %s:%.*s, but it is on "
- "the purge list. Removing\n",
- dlm->name, res->lockname.len,
- res->lockname.name);
- list_del_init(&res->purge);
- dlm->purge_count--;
- }
- return;
- }
-
if (list_empty(&res->purge)) {
- mlog(0, "putting lockres %.*s from purge list\n",
- res->lockname.len, res->lockname.name);
+ mlog(0, "putting lockres %.*s:%p onto purge list\n",
+ res->lockname.len, res->lockname.name, res);
res->last_used = jiffies;
+ dlm_lockres_get(res);
list_add_tail(&res->purge, &dlm->purge_list);
dlm->purge_count++;
-
- /* if this node is not the owner, there is
- * no way to keep track of who the owner could be.
- * unhash it to avoid serious problems. */
- if (res->owner != dlm->node_num) {
- mlog(0, "%s:%.*s: doing immediate "
- "purge of lockres owned by %u\n",
- dlm->name, res->lockname.len,
- res->lockname.name, res->owner);
-
- dlm_purge_lockres_now(dlm, res);
- }
}
} else if (!list_empty(&res->purge)) {
- mlog(0, "removing lockres %.*s from purge list, "
- "owner=%u\n", res->lockname.len, res->lockname.name,
- res->owner);
+ mlog(0, "removing lockres %.*s:%p from purge list, owner=%u\n",
+ res->lockname.len, res->lockname.name, res, res->owner);
list_del_init(&res->purge);
+ dlm_lockres_put(res);
dlm->purge_count--;
}
}
@@ -163,68 +154,60 @@
spin_unlock(&dlm->spinlock);
}
-/* TODO: Eventual API: Called with the dlm spinlock held, may drop it
- * to do migration, but will re-acquire before exit. */
-void dlm_purge_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *lockres)
+int dlm_purge_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
{
int master;
- int ret;
+ int ret = 0;
- spin_lock(&lockres->spinlock);
- master = lockres->owner == dlm->node_num;
- spin_unlock(&lockres->spinlock);
-
- mlog(0, "purging lockres %.*s, master = %d\n", lockres->lockname.len,
- lockres->lockname.name, master);
-
- /* Non master is the easy case -- no migration required, just
- * quit. */
+ spin_lock(&res->spinlock);
+ if (!__dlm_lockres_unused(res)) {
+ spin_unlock(&res->spinlock);
+ mlog(0, "%s:%.*s: tried to purge but not unused\n",
+ dlm->name, res->lockname.len, res->lockname.name);
+ return -ENOTEMPTY;
+ }
+ master = (res->owner == dlm->node_num);
if (!master)
- goto finish;
+ res->state |= DLM_LOCK_RES_DROPPING_REF;
+ spin_unlock(&res->spinlock);
- /* Wheee! Migrate lockres here! */
- spin_unlock(&dlm->spinlock);
-again:
+ mlog(0, "purging lockres %.*s, master = %d\n", res->lockname.len,
+ res->lockname.name, master);
- ret = dlm_migrate_lockres(dlm, lockres, O2NM_MAX_NODES);
- if (ret == -ENOTEMPTY) {
- mlog(ML_ERROR, "lockres %.*s still has local locks!\n",
- lockres->lockname.len, lockres->lockname.name);
-
- BUG();
- } else if (ret < 0) {
- mlog(ML_NOTICE, "lockres %.*s: migrate failed, retrying\n",
- lockres->lockname.len, lockres->lockname.name);
- msleep(100);
- goto again;
+ if (!master) {
+ /* drop spinlock to do messaging, retake below */
+ spin_unlock(&dlm->spinlock);
+ /* clear our bit from the master's refmap, ignore errors */
+ ret = dlm_drop_lockres_ref(dlm, res);
+ if (ret < 0) {
+ mlog_errno(ret);
+ if (!dlm_is_host_down(ret))
+ BUG();
+ }
+ mlog(0, "%s:%.*s: dlm_deref_lockres returned %d\n",
+ dlm->name, res->lockname.len, res->lockname.name, ret);
+ spin_lock(&dlm->spinlock);
}
- spin_lock(&dlm->spinlock);
-
-finish:
- if (!list_empty(&lockres->purge)) {
- list_del_init(&lockres->purge);
+ if (!list_empty(&res->purge)) {
+ mlog(0, "removing lockres %.*s:%p from purgelist, "
+ "master = %d\n", res->lockname.len, res->lockname.name,
+ res, master);
+ list_del_init(&res->purge);
+ dlm_lockres_put(res);
dlm->purge_count--;
}
- __dlm_unhash_lockres(lockres);
-}
+ __dlm_unhash_lockres(res);
-/* make an unused lockres go away immediately.
- * as soon as the dlm spinlock is dropped, this lockres
- * will not be found. kfree still happens on last put. */
-static void dlm_purge_lockres_now(struct dlm_ctxt *dlm,
- struct dlm_lock_resource *lockres)
-{
- assert_spin_locked(&dlm->spinlock);
- assert_spin_locked(&lockres->spinlock);
-
- BUG_ON(!__dlm_lockres_unused(lockres));
-
- if (!list_empty(&lockres->purge)) {
- list_del_init(&lockres->purge);
- dlm->purge_count--;
+ /* lockres is not in the hash now. drop the flag and wake up
+ * any processes waiting in dlm_get_lock_resource. */
+ if (!master) {
+ spin_lock(&res->spinlock);
+ res->state &= ~DLM_LOCK_RES_DROPPING_REF;
+ spin_unlock(&res->spinlock);
+ wake_up(&res->wq);
}
- __dlm_unhash_lockres(lockres);
+ return 0;
}
static void dlm_run_purge_list(struct dlm_ctxt *dlm,
@@ -268,13 +251,17 @@
break;
}
+ mlog(0, "removing lockres %.*s:%p from purgelist\n",
+ lockres->lockname.len, lockres->lockname.name, lockres);
list_del_init(&lockres->purge);
+ dlm_lockres_put(lockres);
dlm->purge_count--;
/* This may drop and reacquire the dlm spinlock if it
* has to do migration. */
mlog(0, "calling dlm_purge_lockres!\n");
- dlm_purge_lockres(dlm, lockres);
+ if (dlm_purge_lockres(dlm, lockres))
+ BUG();
mlog(0, "DONE calling dlm_purge_lockres!\n");
/* Avoid adding any scheduling latencies */