ocfs2/dlm: Refactor dlm_clean_master_list()

This patch refactors dlm_clean_master_list() so as to make it
easier to convert the mle list to a hash.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
index 040581e1cd04a46aaf67151f8b1b9e5fcce70d4b..ec6da3c37dc825af2fcf268c730e2d18f3e24503 100644 (file)
--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -3207,12 +3207,87 @@ static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
        return ret;
 }
 
+/*
+ * Sets the owner of the lockres, associated to the mle, to UNKNOWN
+ */
+static struct dlm_lock_resource *dlm_reset_mleres_owner(struct dlm_ctxt *dlm,
+                                       struct dlm_master_list_entry *mle)
+{
+       struct dlm_lock_resource *res;
+       unsigned int hash;
+
+       /* Find the lockres associated to the mle and set its owner to UNK */
+       hash = dlm_lockid_hash(mle->u.mlename.name, mle->u.mlename.len);
+       res = __dlm_lookup_lockres(dlm, mle->u.mlename.name, mle->u.mlename.len,
+                                  hash);
+       if (res) {
+               spin_unlock(&dlm->master_lock);
+
+               /* move lockres onto recovery list */
+               spin_lock(&res->spinlock);
+               dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
+               dlm_move_lockres_to_recovery_list(dlm, res);
+               spin_unlock(&res->spinlock);
+               dlm_lockres_put(res);
+
+               /* about to get rid of mle, detach from heartbeat */
+               __dlm_mle_detach_hb_events(dlm, mle);
+
+               /* dump the mle */
+               spin_lock(&dlm->master_lock);
+               __dlm_put_mle(mle);
+               spin_unlock(&dlm->master_lock);
+       }
+
+       return res;
+}
+
+static void dlm_clean_migration_mle(struct dlm_ctxt *dlm,
+                                   struct dlm_master_list_entry *mle)
+{
+       __dlm_mle_detach_hb_events(dlm, mle);
+
+       spin_lock(&mle->spinlock);
+       __dlm_unlink_mle(dlm, mle);
+       atomic_set(&mle->woken, 1);
+       spin_unlock(&mle->spinlock);
+
+       wake_up(&mle->wq);
+}
+
+static void dlm_clean_block_mle(struct dlm_ctxt *dlm,
+                               struct dlm_master_list_entry *mle, u8 dead_node)
+{
+       int bit;
+
+       BUG_ON(mle->type != DLM_MLE_BLOCK);
+
+       spin_lock(&mle->spinlock);
+       bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
+       if (bit != dead_node) {
+               mlog(0, "mle found, but dead node %u would not have been "
+                    "master\n", dead_node);
+               spin_unlock(&mle->spinlock);
+       } else {
+               /* Must drop the refcount by one since the assert_master will
+                * never arrive. This may result in the mle being unlinked and
+                * freed, but there may still be a process waiting in the
+                * dlmlock path which is fine. */
+               mlog(0, "node %u was expected master\n", dead_node);
+               atomic_set(&mle->woken, 1);
+               spin_unlock(&mle->spinlock);
+               wake_up(&mle->wq);
+
+               /* Do not need events any longer, so detach from heartbeat */
+               __dlm_mle_detach_hb_events(dlm, mle);
+               __dlm_put_mle(mle);
+       }
+}
 
 void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
 {
        struct dlm_master_list_entry *mle, *next;
        struct dlm_lock_resource *res;
-       unsigned int hash;
 
        mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
 top:
@@ -3236,30 +3311,7 @@ top:
                 * need to clean up if the dead node would have
                 * been the master. */
                if (mle->type == DLM_MLE_BLOCK) {
-                       int bit;
-
-                       spin_lock(&mle->spinlock);
-                       bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
-                       if (bit != dead_node) {
-                               mlog(0, "mle found, but dead node %u would "
-                                    "not have been master\n", dead_node);
-                               spin_unlock(&mle->spinlock);
-                       } else {
-                               /* must drop the refcount by one since the
-                                * assert_master will never arrive.  this
-                                * may result in the mle being unlinked and
-                                * freed, but there may still be a process
-                                * waiting in the dlmlock path which is fine. */
-                               mlog(0, "node %u was expected master\n",
-                                    dead_node);
-                               atomic_set(&mle->woken, 1);
-                               spin_unlock(&mle->spinlock);
-                               wake_up(&mle->wq);
-                               /* do not need events any longer, so detach 
-                                * from heartbeat */
-                               __dlm_mle_detach_hb_events(dlm, mle);
-                               __dlm_put_mle(mle);
-                       }
+                       dlm_clean_block_mle(dlm, mle, dead_node);
                        continue;
                }
 
@@ -3280,51 +3332,21 @@ top:
 
                /* if we have reached this point, this mle needs to
                 * be removed from the list and freed. */
-
-               /* remove from the list early.  NOTE: unlinking
-                * list_head while in list_for_each_safe */
-               __dlm_mle_detach_hb_events(dlm, mle);
-               spin_lock(&mle->spinlock);
-               __dlm_unlink_mle(dlm, mle);
-               atomic_set(&mle->woken, 1);
-               spin_unlock(&mle->spinlock);
-               wake_up(&mle->wq);
+               dlm_clean_migration_mle(dlm, mle);
 
                mlog(0, "%s: node %u died during migration from "
                     "%u to %u!\n", dlm->name, dead_node,
                     mle->master, mle->new_master);
-               /* if there is a lockres associated with this
-                * mle, find it and set its owner to UNKNOWN */
-               hash = dlm_lockid_hash(mle->u.mlename.name, mle->u.mlename.len);
-               res = __dlm_lookup_lockres(dlm, mle->u.mlename.name,
-                                          mle->u.mlename.len, hash);
-               if (res) {
-                       /* unfortunately if we hit this rare case, our
-                        * lock ordering is messed.  we need to drop
-                        * the master lock so that we can take the
-                        * lockres lock, meaning that we will have to
-                        * restart from the head of list. */
-                       spin_unlock(&dlm->master_lock);
-
-                       /* move lockres onto recovery list */
-                       spin_lock(&res->spinlock);
-                       dlm_set_lockres_owner(dlm, res,
-                                       DLM_LOCK_RES_OWNER_UNKNOWN);
-                       dlm_move_lockres_to_recovery_list(dlm, res);
-                       spin_unlock(&res->spinlock);
-                       dlm_lockres_put(res);
-
-                       /* about to get rid of mle, detach from heartbeat */
-                       __dlm_mle_detach_hb_events(dlm, mle);
-
-                       /* dump the mle */
-                       spin_lock(&dlm->master_lock);
-                       __dlm_put_mle(mle);
-                       spin_unlock(&dlm->master_lock);
 
+               /* If we find a lockres associated with the mle, we've
+                * hit this rare case that messes up our lock ordering.
+                * If so, we need to drop the master lock so that we can
+                * take the lockres lock, meaning that we will have to
+                * restart from the head of list. */
+               res = dlm_reset_mleres_owner(dlm, mle);
+               if (res)
                        /* restart */
                        goto top;
-               }
 
                /* this may be the last reference */
                __dlm_put_mle(mle);