1 files changed, 90 insertions, 165 deletions

diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
index 84d166328cf..11eefb8c12e 100644
--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -2339,65 +2339,55 @@ static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data)
         dlm_lockres_put(res);
 }
 
-/* Checks whether the lockres can be migrated. Returns 0 if yes, < 0
- * if not. If 0, numlocks is set to the number of locks in the lockres.
+/*
+ * A migrateable resource is one that is :
+ * 1. locally mastered, and,
+ * 2. zero local locks, and,
+ * 3. one or more non-local locks, or, one or more references
+ * Returns 1 if yes, 0 if not.
  */
 static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm,
-                                      struct dlm_lock_resource *res,
-                                      int *numlocks,
-                                      int *hasrefs)
+                                      struct dlm_lock_resource *res)
 {
-        int ret;
-        int i;
-        int count = 0;
+        enum dlm_lockres_list idx;
+        int nonlocal = 0, node_ref;
         struct list_head *queue;
         struct dlm_lock *lock;
+        u64 cookie;
 
         assert_spin_locked(&res->spinlock);
 
-        *numlocks = 0;
-        *hasrefs = 0;
-
-        ret = -EINVAL;
-        if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
-                mlog(0, "cannot migrate lockres with unknown owner!\n");
-                goto leave;
-        }
-
-        if (res->owner != dlm->node_num) {
-                mlog(0, "cannot migrate lockres this node doesn't own!\n");
-                goto leave;
-        }
+        if (res->owner != dlm->node_num)
+                return 0;
 
-        ret = 0;
-        queue = &res->granted;
-        for (i = 0; i < 3; i++) {
+        for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
+                queue = dlm_list_idx_to_ptr(res, idx);
                 list_for_each_entry(lock, queue, list) {
-                        ++count;
-                        if (lock->ml.node == dlm->node_num) {
-                                mlog(0, "found a lock owned by this node still "
-                                     "on the %s queue!  will not migrate this "
-                                     "lockres\n", (i == 0 ? "granted" :
-                                                   (i == 1 ? "converting" :
-                                                    "blocked")));
-                                ret = -ENOTEMPTY;
-                                goto leave;
+                        if (lock->ml.node != dlm->node_num) {
+                                nonlocal++;
+                                continue;
                         }
+                        cookie = be64_to_cpu(lock->ml.cookie);
+                        mlog(0, "%s: Not migrateable res %.*s, lock %u:%llu on "
+                             "%s list\n", dlm->name, res->lockname.len,
+                             res->lockname.name,
+                             dlm_get_lock_cookie_node(cookie),
+                             dlm_get_lock_cookie_seq(cookie),
+                             dlm_list_in_text(idx));
+                        return 0;
                 }
-                queue++;
         }
 
-        *numlocks = count;
-
-        count = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
-        if (count < O2NM_MAX_NODES)
-                *hasrefs = 1;
+        if (!nonlocal) {
+                node_ref = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
+                if (node_ref >= O2NM_MAX_NODES)
+                        return 0;
+        }
 
-        mlog(0, "%s: res %.*s, Migrateable, locks %d, refs %d\n", dlm->name,
-             res->lockname.len, res->lockname.name, *numlocks, *hasrefs);
+        mlog(0, "%s: res %.*s, Migrateable\n", dlm->name, res->lockname.len,
+             res->lockname.name);
 
-leave:
-        return ret;
+        return 1;
 }
 
 /*
@@ -2406,8 +2396,7 @@ leave:
 
 
 static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
-                               struct dlm_lock_resource *res,
-                               u8 target)
+                               struct dlm_lock_resource *res, u8 target)
 {
         struct dlm_master_list_entry *mle = NULL;
         struct dlm_master_list_entry *oldmle = NULL;
@@ -2416,37 +2405,20 @@ static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
         const char *name;
         unsigned int namelen;
         int mle_added = 0;
-        int numlocks, hasrefs;
         int wake = 0;
 
         if (!dlm_grab(dlm))
                 return -EINVAL;
 
+        BUG_ON(target == O2NM_MAX_NODES);
+
         name = res->lockname.name;
         namelen = res->lockname.len;
 
-        mlog(0, "%s: Migrating %.*s to %u\n", dlm->name, namelen, name, target);
-
-        /*
-         * ensure this lockres is a proper candidate for migration
-         */
-        spin_lock(&res->spinlock);
-        ret = dlm_is_lockres_migrateable(dlm, res, &numlocks, &hasrefs);
-        if (ret < 0) {
-                spin_unlock(&res->spinlock);
-                goto leave;
-        }
-        spin_unlock(&res->spinlock);
-
-        /* no work to do */
-        if (numlocks == 0 && !hasrefs)
-                goto leave;
-
-        /*
-         * preallocate up front
-         * if this fails, abort
-         */
+        mlog(0, "%s: Migrating %.*s to node %u\n", dlm->name, namelen, name,
+             target);
 
+        /* preallocate up front. if this fails, abort */
         ret = -ENOMEM;
         mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
         if (!mres) {
@@ -2462,35 +2434,10 @@ static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
         ret = 0;
 
         /*
-         * find a node to migrate the lockres to
-         */
-
-        spin_lock(&dlm->spinlock);
-        /* pick a new node */
-        if (!test_bit(target, dlm->domain_map) ||
-            target >= O2NM_MAX_NODES) {
-                target = dlm_pick_migration_target(dlm, res);
-        }
-        mlog(0, "%s: res %.*s, Node %u chosen for migration\n", dlm->name,
-             namelen, name, target);
-
-        if (target >= O2NM_MAX_NODES ||
-            !test_bit(target, dlm->domain_map)) {
-                /* target chosen is not alive */
-                ret = -EINVAL;
-        }
-
-        if (ret) {
-                spin_unlock(&dlm->spinlock);
-                goto fail;
-        }
-
-        mlog(0, "continuing with target = %u\n", target);
-
-        /*
          * clear any existing master requests and
          * add the migration mle to the list
          */
+        spin_lock(&dlm->spinlock);
         spin_lock(&dlm->master_lock);
         ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
                                     namelen, target, dlm->node_num);
@@ -2531,6 +2478,7 @@ fail:
                         dlm_put_mle(mle);
                 } else if (mle) {
                         kmem_cache_free(dlm_mle_cache, mle);
+                        mle = NULL;
                 }
                 goto leave;
         }
@@ -2652,69 +2600,52 @@ leave:
         if (wake)
                 wake_up(&res->wq);
 
-        /* TODO: cleanup */
         if (mres)
                 free_page((unsigned long)mres);
 
         dlm_put(dlm);
 
-        mlog(0, "returning %d\n", ret);
+        mlog(0, "%s: Migrating %.*s to %u, returns %d\n", dlm->name, namelen,
+             name, target, ret);
         return ret;
 }
 
 #define DLM_MIGRATION_RETRY_MS  100
 
-/* Should be called only after beginning the domain leave process.
+/*
+ * Should be called only after beginning the domain leave process.
  * There should not be any remaining locks on nonlocal lock resources,
  * and there should be no local locks left on locally mastered resources.
  *
  * Called with the dlm spinlock held, may drop it to do migration, but
  * will re-acquire before exit.
  *
- * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped */
+ * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped
+ */
 int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
 {
         int ret;
         int lock_dropped = 0;
-        int numlocks, hasrefs;
+        u8 target = O2NM_MAX_NODES;
+
+        assert_spin_locked(&dlm->spinlock);
 
         spin_lock(&res->spinlock);
-        if (res->owner != dlm->node_num) {
-                if (!__dlm_lockres_unused(res)) {
-                        mlog(ML_ERROR, "%s:%.*s: this node is not master, "
-                             "trying to free this but locks remain\n",
-                             dlm->name, res->lockname.len, res->lockname.name);
-                }
-                spin_unlock(&res->spinlock);
-                goto leave;
-        }
+        if (dlm_is_lockres_migrateable(dlm, res))
+                target = dlm_pick_migration_target(dlm, res);
+        spin_unlock(&res->spinlock);
 
-        /* No need to migrate a lockres having no locks */
-        ret = dlm_is_lockres_migrateable(dlm, res, &numlocks, &hasrefs);
-        if (ret >= 0 && numlocks == 0 && !hasrefs) {
-                spin_unlock(&res->spinlock);
+        if (target == O2NM_MAX_NODES)
                 goto leave;
-        }
-        spin_unlock(&res->spinlock);
 
         /* Wheee! Migrate lockres here! Will sleep so drop spinlock. */
         spin_unlock(&dlm->spinlock);
         lock_dropped = 1;
-        while (1) {
-                ret = dlm_migrate_lockres(dlm, res, O2NM_MAX_NODES);
-                if (ret >= 0)
-                        break;
-                if (ret == -ENOTEMPTY) {
-                        mlog(ML_ERROR, "lockres %.*s still has local locks!\n",
-                                res->lockname.len, res->lockname.name);
-                        BUG();
-                }
-
-                mlog(0, "lockres %.*s: migrate failed, "
-                     "retrying\n", res->lockname.len,
-                     res->lockname.name);
-                msleep(DLM_MIGRATION_RETRY_MS);
-        }
+        ret = dlm_migrate_lockres(dlm, res, target);
+        if (ret)
+                mlog(0, "%s: res %.*s, Migrate to node %u failed with %d\n",
+                     dlm->name, res->lockname.len, res->lockname.name,
+                     target, ret);
         spin_lock(&dlm->spinlock);
 leave:
         return lock_dropped;
@@ -2898,61 +2829,55 @@ static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
         }
 }
 
-/* for now this is not too intelligent.  we will
- * need stats to make this do the right thing.
- * this just finds the first lock on one of the
- * queues and uses that node as the target. */
+/*
+ * Pick a node to migrate the lock resource to. This function selects a
+ * potential target based first on the locks and then on refmap. It skips
+ * nodes that are in the process of exiting the domain.
+ */
 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
                                     struct dlm_lock_resource *res)
 {
-        int i;
+        enum dlm_lockres_list idx;
         struct list_head *queue = &res->granted;
         struct dlm_lock *lock;
-        int nodenum;
+        int noderef;
+        u8 nodenum = O2NM_MAX_NODES;
 
         assert_spin_locked(&dlm->spinlock);
+        assert_spin_locked(&res->spinlock);
 
-        spin_lock(&res->spinlock);
-        for (i=0; i<3; i++) {
+        /* Go through all the locks */
+        for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
+                queue = dlm_list_idx_to_ptr(res, idx);
                 list_for_each_entry(lock, queue, list) {
-                        /* up to the caller to make sure this node
-                         * is alive */
-                        if (lock->ml.node != dlm->node_num) {
-                                spin_unlock(&res->spinlock);
-                                return lock->ml.node;
-                        }
+                        if (lock->ml.node == dlm->node_num)
+                                continue;
+                        if (test_bit(lock->ml.node, dlm->exit_domain_map))
+                                continue;
+                        nodenum = lock->ml.node;
+                        goto bail;
                 }
-                queue++;
-        }
-
-        nodenum = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
-        if (nodenum < O2NM_MAX_NODES) {
-                spin_unlock(&res->spinlock);
-                return nodenum;
         }
-        spin_unlock(&res->spinlock);
-        mlog(0, "have not found a suitable target yet! checking domain map\n");
 
-        /* ok now we're getting desperate.  pick anyone alive. */
-        nodenum = -1;
+        /* Go thru the refmap */
+        noderef = -1;
         while (1) {
-                nodenum = find_next_bit(dlm->domain_map,
-                                        O2NM_MAX_NODES, nodenum+1);
-                mlog(0, "found %d in domain map\n", nodenum);
-                if (nodenum >= O2NM_MAX_NODES)
+                noderef = find_next_bit(res->refmap, O2NM_MAX_NODES,
+                                        noderef + 1);
+                if (noderef >= O2NM_MAX_NODES)
                         break;
-                if (nodenum != dlm->node_num) {
-                        mlog(0, "picking %d\n", nodenum);
-                        return nodenum;
-                }
+                if (noderef == dlm->node_num)
+                        continue;
+                if (test_bit(noderef, dlm->exit_domain_map))
+                        continue;
+                nodenum = noderef;
+                goto bail;
         }
 
-        mlog(0, "giving up.  no master to migrate to\n");
-        return DLM_LOCK_RES_OWNER_UNKNOWN;
+bail:
+        return nodenum;
 }
 
-
-
 /* this is called by the new master once all lockres
  * data has been received */
 static int dlm_do_migrate_request(struct dlm_ctxt *dlm,