nfsd4: extend the client_lock to cover cl_lru

To be used later on to hold a reference count on the client while in use by a
nfsv4.1 compound.

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 26 insertions, 15 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index aecafb2e4056..3f572cb3f896 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -250,7 +250,7 @@ unhash_delegation(struct nfs4_delegation *dp)
  * SETCLIENTID state 
  */
 
-/* client_lock protects the session hash table */
+/* client_lock protects the client lru list and session hash table */
 static DEFINE_SPINLOCK(client_lock);
 
 /* Hash tables for nfs4_clientid state */
@@ -628,8 +628,9 @@ free_session(struct kref *kref)
         kfree(ses);
 }
 
+/* must be called under the client_lock */
 static inline void
-renew_client(struct nfs4_client *clp)
+renew_client_locked(struct nfs4_client *clp)
 {
         /*
         * Move client to the end to the LRU list.
@@ -641,6 +642,14 @@ renew_client(struct nfs4_client *clp)
         clp->cl_time = get_seconds();
 }
 
+static inline void
+renew_client(struct nfs4_client *clp)
+{
+        spin_lock(&client_lock);
+        renew_client_locked(clp);
+        spin_unlock(&client_lock);
+}
+
 /* SETCLIENTID and SETCLIENTID_CONFIRM Helper functions */
 static int
 STALE_CLIENTID(clientid_t *clid)
@@ -706,14 +715,14 @@ expire_client(struct nfs4_client *clp)
                 list_del_init(&dp->dl_recall_lru);
                 unhash_delegation(dp);
         }
-        list_del(&clp->cl_idhash);
-        list_del(&clp->cl_strhash);
-        list_del(&clp->cl_lru);
         while (!list_empty(&clp->cl_openowners)) {
                 sop = list_entry(clp->cl_openowners.next, struct nfs4_stateowner, so_perclient);
                 release_openowner(sop);
         }
+        list_del(&clp->cl_idhash);
+        list_del(&clp->cl_strhash);
         spin_lock(&client_lock);
+        list_del(&clp->cl_lru);
         while (!list_empty(&clp->cl_sessions)) {
                 struct nfsd4_session  *ses;
                 ses = list_entry(clp->cl_sessions.next, struct nfsd4_session,
@@ -848,8 +857,7 @@ add_to_unconfirmed(struct nfs4_client *clp, unsigned int strhashval)
         list_add(&clp->cl_strhash, &unconf_str_hashtbl[strhashval]);
         idhashval = clientid_hashval(clp->cl_clientid.cl_id);
         list_add(&clp->cl_idhash, &unconf_id_hashtbl[idhashval]);
-        list_add_tail(&clp->cl_lru, &client_lru);
-        clp->cl_time = get_seconds();
+        renew_client(clp);
 }
 
 static void
@@ -1447,15 +1455,12 @@ nfsd4_sequence(struct svc_rqst *rqstp,
 
 out:
         /* Hold a session reference until done processing the compound. */
-        if (cstate->session)
-                nfsd4_get_session(cstate->session);
-        spin_unlock(&client_lock);
-        /* Renew the clientid on success and on replay */
         if (cstate->session) {
-                nfs4_lock_state();
-                renew_client(session->se_client);
-                nfs4_unlock_state();
+                nfsd4_get_session(cstate->session);
+                /* Renew the clientid on success and on replay */
+                renew_client_locked(session->se_client);
         }
+        spin_unlock(&client_lock);
         dprintk("%s: return %d\n", __func__, ntohl(status));
         return status;
 }
@@ -2564,6 +2569,8 @@ nfs4_laundromat(void)
         dprintk("NFSD: laundromat service - starting\n");
         if (locks_in_grace())
                 nfsd4_end_grace();
+        INIT_LIST_HEAD(&reaplist);
+        spin_lock(&client_lock);
         list_for_each_safe(pos, next, &client_lru) {
                 clp = list_entry(pos, struct nfs4_client, cl_lru);
                 if (time_after((unsigned long)clp->cl_time, (unsigned long)cutoff)) {
@@ -2572,12 +2579,16 @@ nfs4_laundromat(void)
                                 clientid_val = t;
                         break;
                 }
+                list_move(&clp->cl_lru, &reaplist);
+        }
+        spin_unlock(&client_lock);
+        list_for_each_safe(pos, next, &reaplist) {
+                clp = list_entry(pos, struct nfs4_client, cl_lru);
                 dprintk("NFSD: purging unused client (clientid %08x)\n",
                         clp->cl_clientid.cl_id);
                 nfsd4_remove_clid_dir(clp);
                 expire_client(clp);
         }
-        INIT_LIST_HEAD(&reaplist);
         spin_lock(&recall_lock);
         list_for_each_safe(pos, next, &del_recall_lru) {
                 dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);