Merge tag 'nfs-for-3.11-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Feature highlights include:
   - Add basic client support for NFSv4.2
   - Add basic client support for Labeled NFS (selinux for NFSv4.2)
   - Fix the use of credentials in NFSv4.1 stateful operations, and add
     support for NFSv4.1 state protection.

  Bugfix highlights:
   - Fix another NFSv4 open state recovery race
   - Fix an NFSv4.1 back channel session regression
   - Various rpc_pipefs races
   - Fix another issue with NFSv3 auth negotiation

  Please note that Labeled NFS does require some additional support from
  the security subsystem.  The relevant changesets have all been
  reviewed and acked by James Morris."

* tag 'nfs-for-3.11-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (54 commits)
  NFS: Set NFS_CS_MIGRATION for NFSv4 mounts
  NFSv4.1 Refactor nfs4_init_session and nfs4_init_channel_attrs
  nfs: have NFSv3 try server-specified auth flavors in turn
  nfs: have nfs_mount fake up a auth_flavs list when the server didn't provide it
  nfs: move server_authlist into nfs_try_mount_request
  nfs: refactor "need_mount" code out of nfs_try_mount
  SUNRPC: PipeFS MOUNT notification optimization for dying clients
  SUNRPC: split client creation routine into setup and registration
  SUNRPC: fix races on PipeFS UMOUNT notifications
  SUNRPC: fix races on PipeFS MOUNT notifications
  NFSv4.1 use pnfs_device maxcount for the objectlayout gdia_maxcount
  NFSv4.1 use pnfs_device maxcount for the blocklayout gdia_maxcount
  NFSv4.1 Fix gdia_maxcount calculation to fit in ca_maxresponsesize
  NFS: Improve legacy idmapping fallback
  NFSv4.1 end back channel session draining
  NFS: Apply v4.1 capabilities to v4.2
  NFSv4.1: Clean up layout segment comparison helper names
  NFSv4.1: layout segment comparison helpers should take 'const' parameters
  NFSv4: Move the DNS resolver into the NFSv4 module
  rpc_pipefs: only set rpc_dentry_ops if d_op isn't already set
  ...

1 files changed, 115 insertions, 84 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 2d7525fbcf25..71fdc0dfa0d2 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -269,7 +269,7 @@ static match_table_t nfs_local_lock_tokens = {
 
 enum {
         Opt_vers_2, Opt_vers_3, Opt_vers_4, Opt_vers_4_0,
-        Opt_vers_4_1,
+        Opt_vers_4_1, Opt_vers_4_2,
 
         Opt_vers_err
 };
@@ -280,6 +280,7 @@ static match_table_t nfs_vers_tokens = {
         { Opt_vers_4, "4" },
         { Opt_vers_4_0, "4.0" },
         { Opt_vers_4_1, "4.1" },
+        { Opt_vers_4_2, "4.2" },
 
         { Opt_vers_err, NULL }
 };
@@ -832,6 +833,7 @@ int nfs_show_stats(struct seq_file *m, struct dentry *root)
                 seq_printf(m, "\n\tnfsv4:\t");
                 seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
                 seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
+                seq_printf(m, ",bm2=0x%x", nfss->attr_bitmask[2]);
                 seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
                 show_sessions(m, nfss);
                 show_pnfs(m, nfss);
@@ -1097,6 +1099,10 @@ static int nfs_parse_version_string(char *string,
                 mnt->version = 4;
                 mnt->minorversion = 1;
                 break;
+        case Opt_vers_4_2:
+                mnt->version = 4;
+                mnt->minorversion = 2;
+                break;
         default:
                 return 0;
         }
@@ -1608,29 +1614,13 @@ out_security_failure:
 }
 
 /*
- * Select a security flavor for this mount.  The selected flavor
- * is planted in args->auth_flavors[0].
- *
- * Returns 0 on success, -EACCES on failure.
+ * Ensure that the specified authtype in args->auth_flavors[0] is supported by
+ * the server. Returns 0 if it's ok, and -EACCES if not.
  */
-static int nfs_select_flavor(struct nfs_parsed_mount_data *args,
-                              struct nfs_mount_request *request)
+static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
+                        rpc_authflavor_t *server_authlist, unsigned int count)
 {
-        unsigned int i, count = *(request->auth_flav_len);
-        rpc_authflavor_t flavor;
-
-        /*
-         * The NFSv2 MNT operation does not return a flavor list.
-         */
-        if (args->mount_server.version != NFS_MNT3_VERSION)
-                goto out_default;
-
-        /*
-         * Certain releases of Linux's mountd return an empty
-         * flavor list in some cases.
-         */
-        if (count == 0)
-                goto out_default;
+        unsigned int i;
 
         /*
          * If the sec= mount option is used, the specified flavor or AUTH_NULL
@@ -1640,60 +1630,19 @@ static int nfs_select_flavor(struct nfs_parsed_mount_data *args,
          * means that the server will ignore the rpc creds, so any flavor
          * can be used.
          */
-        if (args->auth_flavors[0] != RPC_AUTH_MAXFLAVOR) {
-                for (i = 0; i < count; i++) {
-                        if (args->auth_flavors[0] == request->auth_flavs[i] ||
-                            request->auth_flavs[i] == RPC_AUTH_NULL)
-                                goto out;
-                }
-                dfprintk(MOUNT, "NFS: auth flavor %d not supported by server\n",
-                        args->auth_flavors[0]);
-                goto out_err;
-        }
-
-        /*
-         * RFC 2623, section 2.7 suggests we SHOULD prefer the
-         * flavor listed first.  However, some servers list
-         * AUTH_NULL first.  Avoid ever choosing AUTH_NULL.
-         */
         for (i = 0; i < count; i++) {
-                struct rpcsec_gss_info info;
-
-                flavor = request->auth_flavs[i];
-                switch (flavor) {
-                case RPC_AUTH_UNIX:
-                        goto out_set;
-                case RPC_AUTH_NULL:
-                        continue;
-                default:
-                        if (rpcauth_get_gssinfo(flavor, &info) == 0)
-                                goto out_set;
-                }
+                if (args->auth_flavors[0] == server_authlist[i] ||
+                    server_authlist[i] == RPC_AUTH_NULL)
+                        goto out;
         }
 
-        /*
-         * As a last chance, see if the server list contains AUTH_NULL -
-         * if it does, use the default flavor.
-         */
-        for (i = 0; i < count; i++) {
-                if (request->auth_flavs[i] == RPC_AUTH_NULL)
-                        goto out_default;
-        }
-
-        dfprintk(MOUNT, "NFS: no auth flavors in common with server\n");
-        goto out_err;
+        dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
+                args->auth_flavors[0]);
+        return -EACCES;
 
-out_default:
-        /* use default if flavor not already set */
-        flavor = (args->auth_flavors[0] == RPC_AUTH_MAXFLAVOR) ?
-                RPC_AUTH_UNIX : args->auth_flavors[0];
-out_set:
-        args->auth_flavors[0] = flavor;
 out:
-        dfprintk(MOUNT, "NFS: using auth flavor %d\n", args->auth_flavors[0]);
+        dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
         return 0;
-out_err:
-        return -EACCES;
 }
 
 /*
@@ -1701,10 +1650,10 @@ out_err:
  * corresponding to the provided path.
  */
 static int nfs_request_mount(struct nfs_parsed_mount_data *args,
-                             struct nfs_fh *root_fh)
+                             struct nfs_fh *root_fh,
+                             rpc_authflavor_t *server_authlist,
+                             unsigned int *server_authlist_len)
 {
-        rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
-        unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
         struct nfs_mount_request request = {
                 .sap            = (struct sockaddr *)
                                                 &args->mount_server.address,
@@ -1712,7 +1661,7 @@ static int nfs_request_mount(struct nfs_parsed_mount_data *args,
                 .protocol       = args->mount_server.protocol,
                 .fh             = root_fh,
                 .noresvport     = args->flags & NFS_MOUNT_NORESVPORT,
-                .auth_flav_len  = &server_authlist_len,
+                .auth_flav_len  = server_authlist_len,
                 .auth_flavs     = server_authlist,
                 .net            = args->net,
         };
@@ -1756,24 +1705,92 @@ static int nfs_request_mount(struct nfs_parsed_mount_data *args,
                 return status;
         }
 
-        return nfs_select_flavor(args, &request);
+        return 0;
 }
 
-struct dentry *nfs_try_mount(int flags, const char *dev_name,
-                             struct nfs_mount_info *mount_info,
-                             struct nfs_subversion *nfs_mod)
+static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_info,
+                                        struct nfs_subversion *nfs_mod)
 {
         int status;
-        struct nfs_server *server;
+        unsigned int i;
+        bool tried_auth_unix = false;
+        bool auth_null_in_list = false;
+        struct nfs_server *server = ERR_PTR(-EACCES);
+        struct nfs_parsed_mount_data *args = mount_info->parsed;
+        rpc_authflavor_t authlist[NFS_MAX_SECFLAVORS];
+        unsigned int authlist_len = ARRAY_SIZE(authlist);
+
+        status = nfs_request_mount(args, mount_info->mntfh, authlist,
+                                        &authlist_len);
+        if (status)
+                return ERR_PTR(status);
 
-        if (mount_info->parsed->need_mount) {
-                status = nfs_request_mount(mount_info->parsed, mount_info->mntfh);
+        /*
+         * Was a sec= authflavor specified in the options? First, verify
+         * whether the server supports it, and then just try to use it if so.
+         */
+        if (args->auth_flavors[0] != RPC_AUTH_MAXFLAVOR) {
+                status = nfs_verify_authflavor(args, authlist, authlist_len);
+                dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
                 if (status)
                         return ERR_PTR(status);
+                return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
+        }
+
+        /*
+         * No sec= option was provided. RFC 2623, section 2.7 suggests we
+         * SHOULD prefer the flavor listed first. However, some servers list
+         * AUTH_NULL first. Avoid ever choosing AUTH_NULL.
+         */
+        for (i = 0; i < authlist_len; ++i) {
+                rpc_authflavor_t flavor;
+                struct rpcsec_gss_info info;
+
+                flavor = authlist[i];
+                switch (flavor) {
+                case RPC_AUTH_UNIX:
+                        tried_auth_unix = true;
+                        break;
+                case RPC_AUTH_NULL:
+                        auth_null_in_list = true;
+                        continue;
+                default:
+                        if (rpcauth_get_gssinfo(flavor, &info) != 0)
+                                continue;
+                        /* Fallthrough */
+                }
+                dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
+                args->auth_flavors[0] = flavor;
+                server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
+                if (!IS_ERR(server))
+                        return server;
         }
 
-        /* Get a volume representation */
-        server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
+        /*
+         * Nothing we tried so far worked. At this point, give up if we've
+         * already tried AUTH_UNIX or if the server's list doesn't contain
+         * AUTH_NULL
+         */
+        if (tried_auth_unix || !auth_null_in_list)
+                return server;
+
+        /* Last chance! Try AUTH_UNIX */
+        dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
+        args->auth_flavors[0] = RPC_AUTH_UNIX;
+        return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
+}
+
+struct dentry *nfs_try_mount(int flags, const char *dev_name,
+                             struct nfs_mount_info *mount_info,
+                             struct nfs_subversion *nfs_mod)
+{
+        struct nfs_server *server;
+
+        if (mount_info->parsed->need_mount)
+                server = nfs_try_mount_request(mount_info, nfs_mod);
+        else
+                server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
+
         if (IS_ERR(server))
                 return ERR_CAST(server);
 
@@ -2412,7 +2429,21 @@ static int nfs_bdi_register(struct nfs_server *server)
 int nfs_set_sb_security(struct super_block *s, struct dentry *mntroot,
                         struct nfs_mount_info *mount_info)
 {
-        return security_sb_set_mnt_opts(s, &mount_info->parsed->lsm_opts);
+        int error;
+        unsigned long kflags = 0, kflags_out = 0;
+        if (NFS_SB(s)->caps & NFS_CAP_SECURITY_LABEL)
+                kflags |= SECURITY_LSM_NATIVE_LABELS;
+
+        error = security_sb_set_mnt_opts(s, &mount_info->parsed->lsm_opts,
+                                                kflags, &kflags_out);
+        if (error)
+                goto err;
+
+        if (NFS_SB(s)->caps & NFS_CAP_SECURITY_LABEL &&
+                !(kflags_out & SECURITY_LSM_NATIVE_LABELS))
+                NFS_SB(s)->caps &= ~NFS_CAP_SECURITY_LABEL;
+err:
+        return error;
 }
 EXPORT_SYMBOL_GPL(nfs_set_sb_security);