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: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index f9f4845db989e58b7e09f3e46b185f5ff5d2d9e4..19874151e95c9908660132e6a3e2e6d7d2d3c8e4 100644 (file)
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -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)

diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 8646af9b11d2e1b866f1c1e789a5b6001a36c882..86d6214ea022fee66f16f976a17451590edde7b8 100644 (file)
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -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;

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 5ad908e9ce9c332696ed52a85a5c4324a45d8b02..d8b43f0e08fc62b9f99d341f57faea7a14d7420f 100644 (file)
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -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 */