Commit 7b1f1fd1 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4/4.1: Fix bugs in nfs4[01]_walk_client_list 



It is unsafe to use list_for_each_entry_safe() here, because
when we drop the nn->nfs_client_lock, we pin the _current_ list
entry and ensure that it stays in the list, but we don't do the
same for the _next_ list entry. Use of list_for_each_entry() is
therefore the correct thing to do.

Also fix the refcounting in nfs41_walk_client_list().

Finally, ensure that the nfs_client has finished being initialised
and, in the case of NFSv4.1, that the session is set up.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Bryan Schumaker <bjschuma@netapp.com>
Cc: stable@vger.kernel.org [>= 3.7]
parent b193d59a

fs/nfs/nfs4client.c

+28 −16
Original line number Diff line number Diff line
@@ -300,7 +300,7 @@ int nfs40_walk_client_list(struct nfs_client *new, 
			   struct rpc_cred *cred)

{

	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);

	struct nfs_client *pos, *n, *prev = NULL;

	struct nfs_client *pos, *prev = NULL;

	struct nfs4_setclientid_res clid = {

		.clientid	= new->cl_clientid,

		.confirm	= new->cl_confirm,
@@ -308,10 +308,23 @@ int nfs40_walk_client_list(struct nfs_client *new, 
	int status = -NFS4ERR_STALE_CLIENTID;



	spin_lock(&nn->nfs_client_lock);

	list_for_each_entry_safe(pos, n, &nn->nfs_client_list, cl_share_link) {

	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {

		/* If "pos" isn't marked ready, we can't trust the

		 * remaining fields in "pos" */

		if (pos->cl_cons_state < NFS_CS_READY)

		if (pos->cl_cons_state > NFS_CS_READY) {

			atomic_inc(&pos->cl_count);

			spin_unlock(&nn->nfs_client_lock);



			if (prev)

				nfs_put_client(prev);

			prev = pos;



			status = nfs_wait_client_init_complete(pos);

			spin_lock(&nn->nfs_client_lock);

			if (status < 0)

				continue;

		}

		if (pos->cl_cons_state != NFS_CS_READY)

			continue;



		if (pos->rpc_ops != new->rpc_ops)
@@ -423,16 +436,16 @@ int nfs41_walk_client_list(struct nfs_client *new, 
			   struct rpc_cred *cred)

{

	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);

	struct nfs_client *pos, *n, *prev = NULL;

	struct nfs_client *pos, *prev = NULL;

	int status = -NFS4ERR_STALE_CLIENTID;



	spin_lock(&nn->nfs_client_lock);

	list_for_each_entry_safe(pos, n, &nn->nfs_client_list, cl_share_link) {

	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {

		/* If "pos" isn't marked ready, we can't trust the

		 * remaining fields in "pos", especially the client

		 * ID and serverowner fields.  Wait for CREATE_SESSION

		 * to finish. */

		if (pos->cl_cons_state < NFS_CS_READY) {

		if (pos->cl_cons_state > NFS_CS_READY) {

			atomic_inc(&pos->cl_count);

			spin_unlock(&nn->nfs_client_lock);
@@ -440,18 +453,17 @@ int nfs41_walk_client_list(struct nfs_client *new, 
				nfs_put_client(prev);

			prev = pos;



			nfs4_schedule_lease_recovery(pos);

			status = nfs_wait_client_init_complete(pos);

			if (status < 0) {

				nfs_put_client(pos);

				spin_lock(&nn->nfs_client_lock);

				continue;

			if (status == 0) {

				nfs4_schedule_lease_recovery(pos);

				status = nfs4_wait_clnt_recover(pos);

			}

			status = pos->cl_cons_state;

			spin_lock(&nn->nfs_client_lock);

			if (status < 0)

				continue;

		}

		if (pos->cl_cons_state != NFS_CS_READY)

			continue;



		if (pos->rpc_ops != new->rpc_ops)

			continue;
@@ -469,17 +481,17 @@ int nfs41_walk_client_list(struct nfs_client *new, 
			continue;



		atomic_inc(&pos->cl_count);

		spin_unlock(&nn->nfs_client_lock);

		*result = pos;

		dprintk("NFS: <-- %s using nfs_client = %p ({%d})\n",

			__func__, pos, atomic_read(&pos->cl_count));



		*result = pos;

		return 0;

		break;

	}



	/* No matching nfs_client found. */

	spin_unlock(&nn->nfs_client_lock);

	dprintk("NFS: <-- %s status = %d\n", __func__, status);

	if (prev)

		nfs_put_client(prev);

	return status;

}

#endif	/* CONFIG_NFS_V4_1 */

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