NFS: Add SECINFO_NO_NAME procedure

If the client is using NFS v4.1, then we can use SECINFO_NO_NAME to find
the secflavor for the initial mount.  If the server doesn't support
SECINFO_NO_NAME then I fall back on the "guess and check" method used
for v4.0 mounts.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 83 insertions, 1 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 5f4912f72282..892bff53f61d 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2251,13 +2251,14 @@ static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
 static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
                               struct nfs_fsinfo *info)
 {
+        int minor_version = server->nfs_client->cl_minorversion;
         int status = nfs4_lookup_root(server, fhandle, info);
         if ((status == -NFS4ERR_WRONGSEC) && !(server->flags & NFS_MOUNT_SECFLAVOUR))
                 /*
                  * A status of -NFS4ERR_WRONGSEC will be mapped to -EPERM
                  * by nfs4_map_errors() as this function exits.
                  */
-                status = nfs4_find_root_sec(server, fhandle, info);
+                status = nfs_v4_minor_ops[minor_version]->find_root_sec(server, fhandle, info);
         if (status == 0)
                 status = nfs4_server_capabilities(server, fhandle);
         if (status == 0)
@@ -5935,6 +5936,85 @@ out:
         rpc_put_task(task);
         return status;
 }
+
+static int
+_nfs41_proc_secinfo_no_name(struct nfs_server *server, struct nfs_fh *fhandle,
+                    struct nfs_fsinfo *info, struct nfs4_secinfo_flavors *flavors)
+{
+        struct nfs41_secinfo_no_name_args args = {
+                .style = SECINFO_STYLE_CURRENT_FH,
+        };
+        struct nfs4_secinfo_res res = {
+                .flavors = flavors,
+        };
+        struct rpc_message msg = {
+                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SECINFO_NO_NAME],
+                .rpc_argp = &args,
+                .rpc_resp = &res,
+        };
+        return nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
+}
+
+static int
+nfs41_proc_secinfo_no_name(struct nfs_server *server, struct nfs_fh *fhandle,
+                           struct nfs_fsinfo *info, struct nfs4_secinfo_flavors *flavors)
+{
+        struct nfs4_exception exception = { };
+        int err;
+        do {
+                err = _nfs41_proc_secinfo_no_name(server, fhandle, info, flavors);
+                switch (err) {
+                case 0:
+                case -NFS4ERR_WRONGSEC:
+                case -NFS4ERR_NOTSUPP:
+                        break;
+                default:
+                        err = nfs4_handle_exception(server, err, &exception);
+                }
+        } while (exception.retry);
+        return err;
+}
+
+static int
+nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
+                    struct nfs_fsinfo *info)
+{
+        int err;
+        struct page *page;
+        rpc_authflavor_t flavor;
+        struct nfs4_secinfo_flavors *flavors;
+
+        page = alloc_page(GFP_KERNEL);
+        if (!page) {
+                err = -ENOMEM;
+                goto out;
+        }
+
+        flavors = page_address(page);
+        err = nfs41_proc_secinfo_no_name(server, fhandle, info, flavors);
+
+        /*
+         * Fall back on "guess and check" method if
+         * the server doesn't support SECINFO_NO_NAME
+         */
+        if (err == -NFS4ERR_WRONGSEC || err == -NFS4ERR_NOTSUPP) {
+                err = nfs4_find_root_sec(server, fhandle, info);
+                goto out_freepage;
+        }
+        if (err)
+                goto out_freepage;
+
+        flavor = nfs_find_best_sec(flavors);
+        if (err == 0)
+                err = nfs4_lookup_root_sec(server, fhandle, info, flavor);
+
+out_freepage:
+        put_page(page);
+        if (err == -EACCES)
+                return -EPERM;
+out:
+        return err;
+}
 #endif /* CONFIG_NFS_V4_1 */
 
 struct nfs4_state_recovery_ops nfs40_reboot_recovery_ops = {
@@ -5996,6 +6076,7 @@ static const struct nfs4_minor_version_ops nfs_v4_0_minor_ops = {
         .minor_version = 0,
         .call_sync = _nfs4_call_sync,
         .validate_stateid = nfs4_validate_delegation_stateid,
+        .find_root_sec = nfs4_find_root_sec,
         .reboot_recovery_ops = &nfs40_reboot_recovery_ops,
         .nograce_recovery_ops = &nfs40_nograce_recovery_ops,
         .state_renewal_ops = &nfs40_state_renewal_ops,
@@ -6006,6 +6087,7 @@ static const struct nfs4_minor_version_ops nfs_v4_1_minor_ops = {
         .minor_version = 1,
         .call_sync = _nfs4_call_sync_session,
         .validate_stateid = nfs41_validate_delegation_stateid,
+        .find_root_sec = nfs41_find_root_sec,
         .reboot_recovery_ops = &nfs41_reboot_recovery_ops,
         .nograce_recovery_ops = &nfs41_nograce_recovery_ops,
         .state_renewal_ops = &nfs41_state_renewal_ops,