Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8383e460 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4: Use RCU to protect delegations 



Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 13437e12

fs/nfs/delegation.c

+63 −51
Original line number Diff line number Diff line
@@ -27,6 +27,13 @@ static void nfs_free_delegation(struct nfs_delegation *delegation) 
	kfree(delegation);

}



static void nfs_free_delegation_callback(struct rcu_head *head)

{

	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);



	nfs_free_delegation(delegation);

}



static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)

{

	struct inode *inode = state->inode;
@@ -133,10 +140,10 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct 
	delegation->inode = inode;



	spin_lock(&clp->cl_lock);

	if (nfsi->delegation == NULL) {

		list_add(&delegation->super_list, &clp->cl_delegations);

		nfsi->delegation = delegation;

	if (rcu_dereference(nfsi->delegation) == NULL) {

		list_add_rcu(&delegation->super_list, &clp->cl_delegations);

		nfsi->delegation_state = delegation->type;

		rcu_assign_pointer(nfsi->delegation, delegation);

		delegation = NULL;

	} else {

		if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
@@ -157,7 +164,7 @@ static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation * 
	int res = 0;



	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);

	nfs_free_delegation(delegation);

	call_rcu(&delegation->rcu, nfs_free_delegation_callback);

	return res;

}
@@ -191,16 +198,16 @@ static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegat 


static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)

{

	struct nfs_delegation *delegation = nfsi->delegation;

	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);



	if (delegation == NULL)

		goto nomatch;

	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,

				sizeof(delegation->stateid.data)) != 0)

		goto nomatch;

	list_del_init(&delegation->super_list);

	nfsi->delegation = NULL;

	list_del_rcu(&delegation->super_list);

	nfsi->delegation_state = 0;

	rcu_assign_pointer(nfsi->delegation, NULL);

	return delegation;

nomatch:

	return NULL;
@@ -213,7 +220,7 @@ int nfs_inode_return_delegation(struct inode *inode) 
	struct nfs_delegation *delegation;

	int err = 0;



	if (nfsi->delegation_state != 0) {

	if (rcu_dereference(nfsi->delegation) != NULL) {

		spin_lock(&clp->cl_lock);

		delegation = nfs_detach_delegation_locked(nfsi, NULL);

		spin_unlock(&clp->cl_lock);
@@ -235,20 +242,23 @@ void nfs_return_all_delegations(struct super_block *sb) 
	if (clp == NULL)

		return;

restart:

	spin_lock(&clp->cl_lock);

	list_for_each_entry(delegation, &clp->cl_delegations, super_list) {

	rcu_read_lock();

	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {

		if (delegation->inode->i_sb != sb)

			continue;

		inode = igrab(delegation->inode);

		if (inode == NULL)

			continue;

		nfs_detach_delegation_locked(NFS_I(inode), NULL);

		spin_lock(&clp->cl_lock);

		delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);

		spin_unlock(&clp->cl_lock);

		rcu_read_unlock();

		if (delegation != NULL)

			__nfs_inode_return_delegation(inode, delegation);

		iput(inode);

		goto restart;

	}

	spin_unlock(&clp->cl_lock);

	rcu_read_unlock();

}



static int nfs_do_expire_all_delegations(void *ptr)
@@ -259,23 +269,26 @@ static int nfs_do_expire_all_delegations(void *ptr) 


	allow_signal(SIGKILL);

restart:

	spin_lock(&clp->cl_lock);

	if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)

		goto out;

	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)

		goto out;

	list_for_each_entry(delegation, &clp->cl_delegations, super_list) {

	rcu_read_lock();

	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {

		inode = igrab(delegation->inode);

		if (inode == NULL)

			continue;

		nfs_detach_delegation_locked(NFS_I(inode), NULL);

		spin_lock(&clp->cl_lock);

		delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);

		spin_unlock(&clp->cl_lock);

		rcu_read_unlock();

		if (delegation)

			__nfs_inode_return_delegation(inode, delegation);

		iput(inode);

		goto restart;

	}

	rcu_read_unlock();

out:

	spin_unlock(&clp->cl_lock);

	nfs_put_client(clp);

	module_put_and_exit(0);

}
@@ -306,18 +319,21 @@ void nfs_handle_cb_pathdown(struct nfs_client *clp) 
	if (clp == NULL)

		return;

restart:

	spin_lock(&clp->cl_lock);

	list_for_each_entry(delegation, &clp->cl_delegations, super_list) {

	rcu_read_lock();

	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {

		inode = igrab(delegation->inode);

		if (inode == NULL)

			continue;

		nfs_detach_delegation_locked(NFS_I(inode), NULL);

		spin_lock(&clp->cl_lock);

		delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);

		spin_unlock(&clp->cl_lock);

		rcu_read_unlock();

		if (delegation != NULL)

			__nfs_inode_return_delegation(inode, delegation);

		iput(inode);

		goto restart;

	}

	spin_unlock(&clp->cl_lock);

	rcu_read_unlock();

}



struct recall_threadargs {
@@ -391,14 +407,14 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs 
{

	struct nfs_delegation *delegation;

	struct inode *res = NULL;

	spin_lock(&clp->cl_lock);

	list_for_each_entry(delegation, &clp->cl_delegations, super_list) {

	rcu_read_lock();

	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {

		if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {

			res = igrab(delegation->inode);

			break;

		}

	}

	spin_unlock(&clp->cl_lock);

	rcu_read_unlock();

	return res;

}
@@ -408,10 +424,10 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs 
void nfs_delegation_mark_reclaim(struct nfs_client *clp)

{

	struct nfs_delegation *delegation;

	spin_lock(&clp->cl_lock);

	list_for_each_entry(delegation, &clp->cl_delegations, super_list)

	rcu_read_lock();

	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)

		delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;

	spin_unlock(&clp->cl_lock);

	rcu_read_unlock();

}



/*
@@ -419,39 +435,35 @@ void nfs_delegation_mark_reclaim(struct nfs_client *clp) 
 */

void nfs_delegation_reap_unclaimed(struct nfs_client *clp)

{

	struct nfs_delegation *delegation, *n;

	LIST_HEAD(head);

	spin_lock(&clp->cl_lock);

	list_for_each_entry_safe(delegation, n, &clp->cl_delegations, super_list) {

	struct nfs_delegation *delegation;

restart:

	rcu_read_lock();

	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {

		if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)

			continue;

		list_move(&delegation->super_list, &head);

		NFS_I(delegation->inode)->delegation = NULL;

		NFS_I(delegation->inode)->delegation_state = 0;

	}

		spin_lock(&clp->cl_lock);

		delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);

		spin_unlock(&clp->cl_lock);

	while(!list_empty(&head)) {

		delegation = list_entry(head.next, struct nfs_delegation, super_list);

		list_del(&delegation->super_list);

		nfs_free_delegation(delegation);

		rcu_read_unlock();

		if (delegation != NULL)

			call_rcu(&delegation->rcu, nfs_free_delegation_callback);

		goto restart;

	}

	rcu_read_unlock();

}



int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)

{

	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;

	struct nfs_inode *nfsi = NFS_I(inode);

	struct nfs_delegation *delegation;

	int res = 0;

	int ret = 0;



	if (nfsi->delegation_state == 0)

		return 0;

	spin_lock(&clp->cl_lock);

	delegation = nfsi->delegation;

	rcu_read_lock();

	delegation = rcu_dereference(nfsi->delegation);

	if (delegation != NULL) {

		memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));

		res = 1;

		ret = 1;

	}

	spin_unlock(&clp->cl_lock);

	return res;

	rcu_read_unlock();

	return ret;

}

fs/nfs/delegation.h

+10 −4
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ struct nfs_delegation { 
	long flags;

	loff_t maxsize;

	__u64 change_attr;

	struct rcu_head rcu;

};



int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res);
@@ -45,11 +46,16 @@ int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode); 


static inline int nfs_have_delegation(struct inode *inode, int flags)

{

	struct nfs_delegation *delegation;

	int ret = 0;



	flags &= FMODE_READ|FMODE_WRITE;

	smp_rmb();

	if ((NFS_I(inode)->delegation_state & flags) == flags)

		return 1;

	return 0;

	rcu_read_lock();

	delegation = rcu_dereference(NFS_I(inode)->delegation);

	if (delegation != NULL && (delegation->type & flags) == flags)

		ret = 1;

	rcu_read_unlock();

	return ret;

}



#else