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Commit 54ac471c authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Add memory barriers to the nfs_client->cl_cons_state initialisation 



Ensure that a process that uses the nfs_client->cl_cons_state test
for whether the initialisation process is finished does not read
stale data.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 4697bd5e

fs/nfs/client.c

+5 −0
Original line number Original line Diff line number Diff line
@@ -459,6 +459,8 @@ static bool nfs4_cb_match_client(const struct sockaddr *addr, 
	    clp->cl_cons_state == NFS_CS_SESSION_INITING))

	    clp->cl_cons_state == NFS_CS_SESSION_INITING))

		return false;

		return false;





	smp_rmb();



	/* Match the version and minorversion */

	/* Match the version and minorversion */

	if (clp->rpc_ops->version != 4 ||

	if (clp->rpc_ops->version != 4 ||

	    clp->cl_minorversion != minorversion)

	    clp->cl_minorversion != minorversion)
@@ -539,6 +541,8 @@ nfs_found_client(const struct nfs_client_initdata *cl_init, 
		return ERR_PTR(error);

		return ERR_PTR(error);

	}

	}





	smp_rmb();



	BUG_ON(clp->cl_cons_state != NFS_CS_READY);

	BUG_ON(clp->cl_cons_state != NFS_CS_READY);





	dprintk("<-- %s found nfs_client %p for %s\n",

	dprintk("<-- %s found nfs_client %p for %s\n",
@@ -597,6 +601,7 @@ nfs_get_client(const struct nfs_client_initdata *cl_init, 
 */

 */

void nfs_mark_client_ready(struct nfs_client *clp, int state)

void nfs_mark_client_ready(struct nfs_client *clp, int state)

{

{

	smp_wmb();

	clp->cl_cons_state = state;

	clp->cl_cons_state = state;

	wake_up_all(&nfs_client_active_wq);

	wake_up_all(&nfs_client_active_wq);

}

}

fs/nfs/idmap.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -548,6 +548,7 @@ static struct nfs_client *nfs_get_client_for_event(struct net *net, int event) 
		/* Skip nfs_clients that failed to initialise */

		/* Skip nfs_clients that failed to initialise */

		if (clp->cl_cons_state < 0)

		if (clp->cl_cons_state < 0)

			continue;

			continue;

		smp_rmb();

		if (clp->rpc_ops != &nfs_v4_clientops)

		if (clp->rpc_ops != &nfs_v4_clientops)

			continue;

			continue;

		cl_dentry = clp->cl_idmap->idmap_pipe->dentry;

		cl_dentry = clp->cl_idmap->idmap_pipe->dentry;

fs/nfs/nfs4proc.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -5621,6 +5621,7 @@ static int nfs41_check_session_ready(struct nfs_client *clp) 
	}

	}

	if (clp->cl_cons_state < NFS_CS_READY)

	if (clp->cl_cons_state < NFS_CS_READY)

		return -EPROTONOSUPPORT;

		return -EPROTONOSUPPORT;

	smp_rmb();

	return 0;

	return 0;

}

}