nfsd: Protect unconfirmed client creation using client_lock

...instead of relying on the client_mutex.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 22 insertions, 11 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 4b42cb95e315..f149e30475db 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1923,7 +1923,7 @@ add_to_unconfirmed(struct nfs4_client *clp)
         add_clp_to_name_tree(clp, &nn->unconf_name_tree);
         idhashval = clientid_hashval(clp->cl_clientid.cl_id);
         list_add(&clp->cl_idhash, &nn->unconf_id_hashtbl[idhashval]);
-        renew_client(clp);
+        renew_client_locked(clp);
 }
 
 static void
@@ -1937,7 +1937,7 @@ move_to_confirmed(struct nfs4_client *clp)
         rb_erase(&clp->cl_namenode, &nn->unconf_name_tree);
         add_clp_to_name_tree(clp, &nn->conf_name_tree);
         set_bit(NFSD4_CLIENT_CONFIRMED, &clp->cl_flags);
-        renew_client(clp);
+        renew_client_locked(clp);
 }
 
 static struct nfs4_client *
@@ -1950,7 +1950,7 @@ find_client_in_id_table(struct list_head *tbl, clientid_t *clid, bool sessions)
                 if (same_clid(&clp->cl_clientid, clid)) {
                         if ((bool)clp->cl_minorversion != sessions)
                                 return NULL;
-                        renew_client(clp);
+                        renew_client_locked(clp);
                         return clp;
                 }
         }
@@ -2152,7 +2152,8 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
                   struct nfsd4_compound_state *cstate,
                   struct nfsd4_exchange_id *exid)
 {
-        struct nfs4_client *unconf, *conf, *new;
+        struct nfs4_client *conf, *new;
+        struct nfs4_client *unconf = NULL;
         __be32 status;
         char                    addr_str[INET6_ADDRSTRLEN];
         nfs4_verifier           verf = exid->verifier;
@@ -2187,6 +2188,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
 
         /* Cases below refer to rfc 5661 section 18.35.4: */
         nfs4_lock_state();
+        spin_lock(&nn->client_lock);
         conf = find_confirmed_client_by_name(&exid->clname, nn);
         if (conf) {
                 bool creds_match = same_creds(&conf->cl_cred, &rqstp->rq_cred);
@@ -2218,7 +2220,6 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
                                 status = nfserr_clid_inuse;
                                 goto out;
                         }
-                        expire_client(conf);
                         goto out_new;
                 }
                 if (verfs_match) { /* case 2 */
@@ -2226,6 +2227,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
                         goto out_copy;
                 }
                 /* case 5, client reboot */
+                conf = NULL;
                 goto out_new;
         }
 
@@ -2236,17 +2238,18 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
 
         unconf  = find_unconfirmed_client_by_name(&exid->clname, nn);
         if (unconf) /* case 4, possible retry or client restart */
-                expire_client(unconf);
+                unhash_client_locked(unconf);
 
         /* case 1 (normal case) */
 out_new:
+        if (conf)
+                unhash_client_locked(conf);
         new->cl_minorversion = cstate->minorversion;
         new->cl_mach_cred = (exid->spa_how == SP4_MACH_CRED);
 
         gen_clid(new, nn);
         add_to_unconfirmed(new);
-        conf = new;
-        new = NULL;
+        swap(new, conf);
 out_copy:
         exid->clientid.cl_boot = conf->cl_clientid.cl_boot;
         exid->clientid.cl_id = conf->cl_clientid.cl_id;
@@ -2259,9 +2262,12 @@ out_copy:
         status = nfs_ok;
 
 out:
+        spin_unlock(&nn->client_lock);
         nfs4_unlock_state();
         if (new)
-                free_client(new);
+                expire_client(new);
+        if (unconf)
+                expire_client(unconf);
         return status;
 }
 
@@ -2900,7 +2906,8 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 {
         struct xdr_netobj       clname = setclid->se_name;
         nfs4_verifier           clverifier = setclid->se_verf;
-        struct nfs4_client      *conf, *unconf, *new;
+        struct nfs4_client      *conf, *new;
+        struct nfs4_client      *unconf = NULL;
         __be32                  status;
         struct nfsd_net         *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 
@@ -2909,6 +2916,7 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                 return nfserr_jukebox;
         /* Cases below refer to rfc 3530 section 14.2.33: */
         nfs4_lock_state();
+        spin_lock(&nn->client_lock);
         conf = find_confirmed_client_by_name(&clname, nn);
         if (conf) {
                 /* case 0: */
@@ -2926,7 +2934,7 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
         }
         unconf = find_unconfirmed_client_by_name(&clname, nn);
         if (unconf)
-                expire_client(unconf);
+                unhash_client_locked(unconf);
         if (conf && same_verf(&conf->cl_verifier, &clverifier))
                 /* case 1: probable callback update */
                 copy_clid(new, conf);
@@ -2941,9 +2949,12 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
         new = NULL;
         status = nfs_ok;
 out:
+        spin_unlock(&nn->client_lock);
         nfs4_unlock_state();
         if (new)
                 free_client(new);
+        if (unconf)
+                expire_client(unconf);
         return status;
 }