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Commit 9ae075fd authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4: Convert open state lookup to use RCU 



Further reduce contention on the inode->i_lock.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 0de43976

fs/nfs/nfs4_fs.h

+1 −0
Original line number Diff line number Diff line
@@ -191,6 +191,7 @@ struct nfs4_state { 
	atomic_t count;



	wait_queue_head_t waitq;

	struct rcu_head rcu_head;

};

fs/nfs/nfs4state.c

+6 −6
Original line number Diff line number Diff line
@@ -684,7 +684,7 @@ __nfs4_find_state_byowner(struct inode *inode, struct nfs4_state_owner *owner) 
	struct nfs_inode *nfsi = NFS_I(inode);

	struct nfs4_state *state;



	list_for_each_entry(state, &nfsi->open_states, inode_states) {

	list_for_each_entry_rcu(state, &nfsi->open_states, inode_states) {

		if (state->owner != owner)

			continue;

		if (!nfs4_valid_open_stateid(state))
@@ -698,7 +698,7 @@ __nfs4_find_state_byowner(struct inode *inode, struct nfs4_state_owner *owner) 
static void

nfs4_free_open_state(struct nfs4_state *state)

{

	kfree(state);

	kfree_rcu(state, rcu_head);

}



struct nfs4_state *
@@ -707,9 +707,9 @@ nfs4_get_open_state(struct inode *inode, struct nfs4_state_owner *owner) 
	struct nfs4_state *state, *new;

	struct nfs_inode *nfsi = NFS_I(inode);



	spin_lock(&inode->i_lock);

	rcu_read_lock();

	state = __nfs4_find_state_byowner(inode, owner);

	spin_unlock(&inode->i_lock);

	rcu_read_unlock();

	if (state)

		goto out;

	new = nfs4_alloc_open_state();
@@ -720,7 +720,7 @@ nfs4_get_open_state(struct inode *inode, struct nfs4_state_owner *owner) 
		state = new;

		state->owner = owner;

		atomic_inc(&owner->so_count);

		list_add(&state->inode_states, &nfsi->open_states);

		list_add_rcu(&state->inode_states, &nfsi->open_states);

		ihold(inode);

		state->inode = inode;

		spin_unlock(&inode->i_lock);
@@ -746,7 +746,7 @@ void nfs4_put_open_state(struct nfs4_state *state) 
	if (!atomic_dec_and_lock(&state->count, &owner->so_lock))

		return;

	spin_lock(&inode->i_lock);

	list_del(&state->inode_states);

	list_del_rcu(&state->inode_states);

	list_del(&state->open_states);

	spin_unlock(&inode->i_lock);

	spin_unlock(&owner->so_lock);