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Commit 48d66b97 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4: Fix a race in NFSv4.1 server trunking discovery 



We do not want to allow a race with another NFS mount to cause
nfs41_walk_client_list() to establish a lease on our nfs_client before
we're done checking for trunking.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent ef070dcb

fs/nfs/client.c

+1 −1
Original line number Diff line number Diff line
@@ -433,7 +433,7 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat 


static bool nfs_client_init_is_complete(const struct nfs_client *clp)

{

	return clp->cl_cons_state != NFS_CS_INITING;

	return clp->cl_cons_state <= NFS_CS_READY;

}



int nfs_wait_client_init_complete(const struct nfs_client *clp)

fs/nfs/nfs4client.c

+4 −5
Original line number Diff line number Diff line
@@ -621,6 +621,9 @@ int nfs41_walk_client_list(struct nfs_client *new, 
	spin_lock(&nn->nfs_client_lock);

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



		if (pos == new)

			goto found;



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

			continue;
@@ -639,10 +642,6 @@ int nfs41_walk_client_list(struct nfs_client *new, 
			prev = pos;



			status = nfs_wait_client_init_complete(pos);

			if (pos->cl_cons_state == NFS_CS_SESSION_INITING) {

				nfs4_schedule_lease_recovery(pos);

				status = nfs4_wait_clnt_recover(pos);

			}

			spin_lock(&nn->nfs_client_lock);

			if (status < 0)

				break;
@@ -668,7 +667,7 @@ int nfs41_walk_client_list(struct nfs_client *new, 
		 */

		if (!nfs4_match_client_owner_id(pos, new))

			continue;



found:

		atomic_inc(&pos->cl_count);

		*result = pos;

		status = 0;

fs/nfs/nfs4state.c

+12 −2
Original line number Diff line number Diff line
@@ -346,9 +346,19 @@ int nfs41_discover_server_trunking(struct nfs_client *clp, 
	status = nfs4_proc_exchange_id(clp, cred);

	if (status != NFS4_OK)

		return status;

	set_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);



	return nfs41_walk_client_list(clp, result, cred);

	status = nfs41_walk_client_list(clp, result, cred);

	if (status < 0)

		return status;

	if (clp != *result)

		return 0;



	set_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);

	nfs4_schedule_state_manager(clp);

	status = nfs_wait_client_init_complete(clp);

	if (status < 0)

		nfs_put_client(clp);

	return status;

}



#endif /* CONFIG_NFS_V4_1 */