Merge tag 'nfs-for-3.5-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfixes from Trond Myklebust:
 - Fix a write hang due to an uninitalised variable when
   !defined(CONFIG_NFS_V4)
 - Address upcall races in the legacy NFSv4 idmapper
 - Remove an O_DIRECT refcounting issue
 - Fix a pNFS refcounting bug when the file layout metadata server is
   also acting as a data server
 - Fix a pNFS module loading race.

* tag 'nfs-for-3.5-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFS: Force the legacy idmapper to be single threaded
  NFS: Initialise commit_info.rpc_out when !defined(CONFIG_NFS_V4)
  NFS: Fix a refcounting issue in O_DIRECT
  NFSv4.1: Fix a race in set_pnfs_layoutdriver
  NFSv4.1: Fix umount when filelayout DS is also the MDS

6 files changed, 20 insertions, 11 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 17ba6b995659..f005b5bebdc7 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -207,7 +207,6 @@ error_0:
 static void nfs4_shutdown_session(struct nfs_client *clp)
 {
         if (nfs4_has_session(clp)) {
-                nfs4_deviceid_purge_client(clp);
                 nfs4_destroy_session(clp->cl_session);
                 nfs4_destroy_clientid(clp);
         }
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 3168f6e3d4d4..9a4cbfc85d81 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -490,6 +490,7 @@ static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq)
                         dreq->error = -EIO;
                         spin_unlock(cinfo.lock);
                 }
+                nfs_release_request(req);
         }
         nfs_pageio_complete(&desc);
 
diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index b5b86a05059c..864c51e4b400 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -57,6 +57,11 @@ unsigned int nfs_idmap_cache_timeout = 600;
 static const struct cred *id_resolver_cache;
 static struct key_type key_type_id_resolver_legacy;
 
+struct idmap {
+        struct rpc_pipe         *idmap_pipe;
+        struct key_construction *idmap_key_cons;
+        struct mutex            idmap_mutex;
+};
 
 /**
  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
@@ -310,9 +315,11 @@ static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
                                             name, namelen, type, data,
                                             data_size, NULL);
         if (ret < 0) {
+                mutex_lock(&idmap->idmap_mutex);
                 ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
                                             name, namelen, type, data,
                                             data_size, idmap);
+                mutex_unlock(&idmap->idmap_mutex);
         }
         return ret;
 }
@@ -354,11 +361,6 @@ static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *typ
 /* idmap classic begins here */
 module_param(nfs_idmap_cache_timeout, int, 0644);
 
-struct idmap {
-        struct rpc_pipe         *idmap_pipe;
-        struct key_construction *idmap_key_cons;
-};
-
 enum {
         Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
 };
@@ -469,6 +471,7 @@ nfs_idmap_new(struct nfs_client *clp)
                 return error;
         }
         idmap->idmap_pipe = pipe;
+        mutex_init(&idmap->idmap_mutex);
 
         clp->cl_idmap = idmap;
         return 0;
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index e605d695dbcb..f7296983eba6 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1530,7 +1530,6 @@ static inline void nfs4_init_once(struct nfs_inode *nfsi)
         nfsi->delegation_state = 0;
         init_rwsem(&nfsi->rwsem);
         nfsi->layout = NULL;
-        atomic_set(&nfsi->commit_info.rpcs_out, 0);
 #endif
 }
 
@@ -1545,6 +1544,7 @@ static void init_once(void *foo)
         INIT_LIST_HEAD(&nfsi->commit_info.list);
         nfsi->npages = 0;
         nfsi->commit_info.ncommit = 0;
+        atomic_set(&nfsi->commit_info.rpcs_out, 0);
         atomic_set(&nfsi->silly_count, 1);
         INIT_HLIST_HEAD(&nfsi->silly_list);
         init_waitqueue_head(&nfsi->waitqueue);
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index b8323aa7b543..bbc49caa7a82 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -70,6 +70,10 @@ find_pnfs_driver(u32 id)
 
         spin_lock(&pnfs_spinlock);
         local = find_pnfs_driver_locked(id);
+        if (local != NULL && !try_module_get(local->owner)) {
+                dprintk("%s: Could not grab reference on module\n", __func__);
+                local = NULL;
+        }
         spin_unlock(&pnfs_spinlock);
         return local;
 }
@@ -80,6 +84,9 @@ unset_pnfs_layoutdriver(struct nfs_server *nfss)
         if (nfss->pnfs_curr_ld) {
                 if (nfss->pnfs_curr_ld->clear_layoutdriver)
                         nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
+                /* Decrement the MDS count. Purge the deviceid cache if zero */
+                if (atomic_dec_and_test(&nfss->nfs_client->cl_mds_count))
+                        nfs4_deviceid_purge_client(nfss->nfs_client);
                 module_put(nfss->pnfs_curr_ld->owner);
         }
         nfss->pnfs_curr_ld = NULL;
@@ -115,10 +122,6 @@ set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
                         goto out_no_driver;
                 }
         }
-        if (!try_module_get(ld_type->owner)) {
-                dprintk("%s: Could not grab reference on module\n", __func__);
-                goto out_no_driver;
-        }
         server->pnfs_curr_ld = ld_type;
         if (ld_type->set_layoutdriver
             && ld_type->set_layoutdriver(server, mntfh)) {
@@ -127,6 +130,8 @@ set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
                 module_put(ld_type->owner);
                 goto out_no_driver;
         }
+        /* Bump the MDS count */
+        atomic_inc(&server->nfs_client->cl_mds_count);
 
         dprintk("%s: pNFS module for %u set\n", __func__, id);
         return;
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index fbb78fb09bd2..f58325a1d8fb 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -25,6 +25,7 @@ struct nfs41_impl_id;
  */
 struct nfs_client {
         atomic_t                cl_count;
+        atomic_t                cl_mds_count;
         int                     cl_cons_state;  /* current construction state (-ve: init error) */
 #define NFS_CS_READY            0               /* ready to be used */
 #define NFS_CS_INITING          1               /* busy initialising */