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Commit 4697bd5e authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4: Fix a race in the net namespace mount notification 



Since the struct nfs_client gets added to the global nfs_client_list
before it is initialised, it is possible that rpc_pipefs_event can
end up trying to create idmapper entries on such a thing.

The solution is to have the mount notification wait for the
initialisation of each nfs_client to complete, and then to
skip any entries for which the it failed.

Reported-by: default avatarStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: default avatarStanislav Kinsbursky <skinsbursky@parallels.com>
parent 7b38c368

fs/nfs/client.c

+13 −3
Original line number Original line Diff line number Diff line
@@ -507,6 +507,17 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat 
	return NULL;

	return NULL;

}

}





static bool nfs_client_init_is_complete(const struct nfs_client *clp)

{

	return clp->cl_cons_state != NFS_CS_INITING;

}



int nfs_wait_client_init_complete(const struct nfs_client *clp)

{

	return wait_event_killable(nfs_client_active_wq,

			nfs_client_init_is_complete(clp));

}



/*

/*

 * Found an existing client.  Make sure it's ready before returning.

 * Found an existing client.  Make sure it's ready before returning.

 */

 */
@@ -516,8 +527,7 @@ nfs_found_client(const struct nfs_client_initdata *cl_init, 
{

{

	int error;

	int error;





	error = wait_event_killable(nfs_client_active_wq,

	error = nfs_wait_client_init_complete(clp);

				clp->cl_cons_state < NFS_CS_INITING);

	if (error < 0) {

	if (error < 0) {

		nfs_put_client(clp);

		nfs_put_client(clp);

		return ERR_PTR(-ERESTARTSYS);

		return ERR_PTR(-ERESTARTSYS);
@@ -1333,7 +1343,7 @@ static int nfs4_init_client_minor_version(struct nfs_client *clp) 
		 * so that the client back channel can find the

		 * so that the client back channel can find the

		 * nfs_client struct

		 * nfs_client struct

		 */

		 */

		clp->cl_cons_state = NFS_CS_SESSION_INITING;

		nfs_mark_client_ready(clp, NFS_CS_SESSION_INITING);

	}

	}

#endif /* CONFIG_NFS_V4_1 */

#endif /* CONFIG_NFS_V4_1 */

fs/nfs/idmap.c

+15 −0
Original line number Original line Diff line number Diff line
@@ -530,9 +530,24 @@ static struct nfs_client *nfs_get_client_for_event(struct net *net, int event) 
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	struct nfs_net *nn = net_generic(net, nfs_net_id);

	struct dentry *cl_dentry;

	struct dentry *cl_dentry;

	struct nfs_client *clp;

	struct nfs_client *clp;

	int err;





restart:

	spin_lock(&nn->nfs_client_lock);

	spin_lock(&nn->nfs_client_lock);

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

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

		/* Wait for initialisation to finish */

		if (clp->cl_cons_state == NFS_CS_INITING) {

			atomic_inc(&clp->cl_count);

			spin_unlock(&nn->nfs_client_lock);

			err = nfs_wait_client_init_complete(clp);

			nfs_put_client(clp);

			if (err)

				return NULL;

			goto restart;

		}

		/* Skip nfs_clients that failed to initialise */

		if (clp->cl_cons_state < 0)

			continue;

		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/internal.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -168,6 +168,7 @@ extern struct nfs_server *nfs_clone_server(struct nfs_server *, 
					   struct nfs_fh *,

					   struct nfs_fh *,

					   struct nfs_fattr *,

					   struct nfs_fattr *,

					   rpc_authflavor_t);

					   rpc_authflavor_t);

extern int nfs_wait_client_init_complete(const struct nfs_client *clp);

extern void nfs_mark_client_ready(struct nfs_client *clp, int state);

extern void nfs_mark_client_ready(struct nfs_client *clp, int state);

extern struct nfs_client *nfs4_set_ds_client(struct nfs_client* mds_clp,

extern struct nfs_client *nfs4_set_ds_client(struct nfs_client* mds_clp,

					     const struct sockaddr *ds_addr,

					     const struct sockaddr *ds_addr,