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Commit c2cd4a44 authored by Sunil Mushran's avatar Sunil Mushran Committed by Mark Fasheh
Browse files

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: default avatarSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
parent f77a9a78

fs/ocfs2/dlm/dlmmaster.c

+85 −63
Original line number Diff line number Diff line
@@ -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);