fs/nfs/nfs4session.c

   1 /*
   2  * fs/nfs/nfs4session.c
   3  *
   4  * Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>
   5  *
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/errno.h>
   9 #include <linux/string.h>
  10 #include <linux/printk.h>
  11 #include <linux/slab.h>
  12 #include <linux/sunrpc/sched.h>
  13 #include <linux/sunrpc/bc_xprt.h>
  14 #include <linux/nfs.h>
  15 #include <linux/nfs4.h>
  16 #include <linux/nfs_fs.h>
  17 #include <linux/module.h>
  18
  19 #include "nfs4_fs.h"
  20 #include "internal.h"
  21 #include "nfs4session.h"
  22 #include "callback.h"
  23
  24 #define NFSDBG_FACILITY         NFSDBG_STATE
  25
  26 static void nfs4_init_slot_table(struct nfs4_slot_table *tbl, const char *queue)
  27 {
  28         tbl->highest_used_slotid = NFS4_NO_SLOT;
  29         spin_lock_init(&tbl->slot_tbl_lock);
  30         rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, queue);
  31         init_waitqueue_head(&tbl->slot_waitq);
  32         init_completion(&tbl->complete);
  33 }
  34
  35 /*
  36  * nfs4_shrink_slot_table - free retired slots from the slot table
  37  */
  38 static void nfs4_shrink_slot_table(struct nfs4_slot_table  *tbl, u32 newsize)
  39 {
  40         struct nfs4_slot **p;
  41         if (newsize >= tbl->max_slots)
  42                 return;
  43
  44         p = &tbl->slots;
  45         while (newsize--)
  46                 p = &(*p)->next;
  47         while (*p) {
  48                 struct nfs4_slot *slot = *p;
  49
  50                 *p = slot->next;
  51                 kfree(slot);
  52                 tbl->max_slots--;
  53         }
  54 }
  55
  56 /**
  57  * nfs4_slot_tbl_drain_complete - wake waiters when drain is complete
  58  * @tbl - controlling slot table
  59  *
  60  */
  61 void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl)
  62 {
  63         if (nfs4_slot_tbl_draining(tbl))
  64                 complete(&tbl->complete);
  65 }
  66
  67 /*
  68  * nfs4_free_slot - free a slot and efficiently update slot table.
  69  *
  70  * freeing a slot is trivially done by clearing its respective bit
  71  * in the bitmap.
  72  * If the freed slotid equals highest_used_slotid we want to update it
  73  * so that the server would be able to size down the slot table if needed,
  74  * otherwise we know that the highest_used_slotid is still in use.
  75  * When updating highest_used_slotid there may be "holes" in the bitmap
  76  * so we need to scan down from highest_used_slotid to 0 looking for the now
  77  * highest slotid in use.
  78  * If none found, highest_used_slotid is set to NFS4_NO_SLOT.
  79  *
  80  * Must be called while holding tbl->slot_tbl_lock
  81  */
  82 void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
  83 {
  84         u32 slotid = slot->slot_nr;
  85
  86         /* clear used bit in bitmap */
  87         __clear_bit(slotid, tbl->used_slots);
  88
  89         /* update highest_used_slotid when it is freed */
  90         if (slotid == tbl->highest_used_slotid) {
  91                 u32 new_max = find_last_bit(tbl->used_slots, slotid);
  92                 if (new_max < slotid)
  93                         tbl->highest_used_slotid = new_max;
  94                 else {
  95                         tbl->highest_used_slotid = NFS4_NO_SLOT;
  96                         nfs4_slot_tbl_drain_complete(tbl);
  97                 }
  98         }
  99         dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
 100                 slotid, tbl->highest_used_slotid);
 101 }
 102
 103 static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table  *tbl,
 104                 u32 slotid, u32 seq_init, gfp_t gfp_mask)
 105 {
 106         struct nfs4_slot *slot;
 107
 108         slot = kzalloc(sizeof(*slot), gfp_mask);
 109         if (slot) {
 110                 slot->table = tbl;
 111                 slot->slot_nr = slotid;
 112                 slot->seq_nr = seq_init;
 113         }
 114         return slot;
 115 }
 116
 117 static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table  *tbl,
 118                 u32 slotid, u32 seq_init, gfp_t gfp_mask)
 119 {
 120         struct nfs4_slot **p, *slot;
 121
 122         p = &tbl->slots;
 123         for (;;) {
 124                 if (*p == NULL) {
 125                         *p = nfs4_new_slot(tbl, tbl->max_slots,
 126                                         seq_init, gfp_mask);
 127                         if (*p == NULL)
 128                                 break;
 129                         tbl->max_slots++;
 130                 }
 131                 slot = *p;
 132                 if (slot->slot_nr == slotid)
 133                         return slot;
 134                 p = &slot->next;
 135         }
 136         return ERR_PTR(-ENOMEM);
 137 }
 138
 139 static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
 140                 struct nfs4_slot *slot)
 141 {
 142         u32 slotid = slot->slot_nr;
 143
 144         __set_bit(slotid, tbl->used_slots);
 145         if (slotid > tbl->highest_used_slotid ||
 146             tbl->highest_used_slotid == NFS4_NO_SLOT)
 147                 tbl->highest_used_slotid = slotid;
 148         slot->generation = tbl->generation;
 149 }
 150
 151 /*
 152  * nfs4_try_to_lock_slot - Given a slot try to allocate it
 153  *
 154  * Note: must be called with the slot_tbl_lock held.
 155  */
 156 bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
 157 {
 158         if (nfs4_test_locked_slot(tbl, slot->slot_nr))
 159                 return false;
 160         nfs4_lock_slot(tbl, slot);
 161         return true;
 162 }
 163
 164 /*
 165  * nfs4_lookup_slot - Find a slot but don't allocate it
 166  *
 167  * Note: must be called with the slot_tbl_lock held.
 168  */
 169 struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid)
 170 {
 171         if (slotid <= tbl->max_slotid)
 172                 return nfs4_find_or_create_slot(tbl, slotid, 0, GFP_NOWAIT);
 173         return ERR_PTR(-E2BIG);
 174 }
 175
 176 static int nfs4_slot_get_seqid(struct nfs4_slot_table  *tbl, u32 slotid,
 177                 u32 *seq_nr)
 178         __must_hold(&tbl->slot_tbl_lock)
 179 {
 180         struct nfs4_slot *slot;
 181         int ret;
 182
 183         slot = nfs4_lookup_slot(tbl, slotid);
 184         ret = PTR_ERR_OR_ZERO(slot);
 185         if (!ret)
 186                 *seq_nr = slot->seq_nr;
 187
 188         return ret;
 189 }
 190
 191 /*
 192  * nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
 193  *
 194  * Given a slot table, slot id and sequence number, determine if the
 195  * RPC call in question is still in flight. This function is mainly
 196  * intended for use by the callback channel.
 197  */
 198 static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl,
 199                 u32 slotid, u32 seq_nr)
 200 {
 201         u32 cur_seq = 0;
 202         bool ret = false;
 203
 204         spin_lock(&tbl->slot_tbl_lock);
 205         if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
 206             cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
 207                 ret = true;
 208         spin_unlock(&tbl->slot_tbl_lock);
 209         return ret;
 210 }
 211
 212 /*
 213  * nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete
 214  *
 215  * Given a slot table, slot id and sequence number, wait until the
 216  * corresponding RPC call completes. This function is mainly
 217  * intended for use by the callback channel.
 218  */
 219 int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
 220                 u32 slotid, u32 seq_nr,
 221                 unsigned long timeout)
 222 {
 223         if (wait_event_timeout(tbl->slot_waitq,
 224                         !nfs4_slot_seqid_in_use(tbl, slotid, seq_nr),
 225                         timeout) == 0)
 226                 return -ETIMEDOUT;
 227         return 0;
 228 }
 229
 230 /*
 231  * nfs4_alloc_slot - efficiently look for a free slot
 232  *
 233  * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
 234  * If found, we mark the slot as used, update the highest_used_slotid,
 235  * and respectively set up the sequence operation args.
 236  *
 237  * Note: must be called with under the slot_tbl_lock.
 238  */
 239 struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
 240 {
 241         struct nfs4_slot *ret = ERR_PTR(-EBUSY);
 242         u32 slotid;
 243
 244         dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
 245                 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
 246                 tbl->max_slotid + 1);
 247         slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
 248         if (slotid <= tbl->max_slotid) {
 249                 ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
 250                 if (!IS_ERR(ret))
 251                         nfs4_lock_slot(tbl, ret);
 252         }
 253         dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
 254                 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
 255                 !IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
 256         return ret;
 257 }
 258
 259 static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
 260                  u32 max_reqs, u32 ivalue)
 261 {
 262         if (max_reqs <= tbl->max_slots)
 263                 return 0;
 264         if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
 265                 return 0;
 266         return -ENOMEM;
 267 }
 268
 269 static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
 270                 u32 server_highest_slotid,
 271                 u32 ivalue)
 272 {
 273         struct nfs4_slot **p;
 274
 275         nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
 276         p = &tbl->slots;
 277         while (*p) {
 278                 (*p)->seq_nr = ivalue;
 279                 (*p)->interrupted = 0;
 280                 p = &(*p)->next;
 281         }
 282         tbl->highest_used_slotid = NFS4_NO_SLOT;
 283         tbl->target_highest_slotid = server_highest_slotid;
 284         tbl->server_highest_slotid = server_highest_slotid;
 285         tbl->d_target_highest_slotid = 0;
 286         tbl->d2_target_highest_slotid = 0;
 287         tbl->max_slotid = server_highest_slotid;
 288 }
 289
 290 /*
 291  * (re)Initialise a slot table
 292  */
 293 static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
 294                 u32 max_reqs, u32 ivalue)
 295 {
 296         int ret;
 297
 298         dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
 299                 max_reqs, tbl->max_slots);
 300
 301         if (max_reqs > NFS4_MAX_SLOT_TABLE)
 302                 max_reqs = NFS4_MAX_SLOT_TABLE;
 303
 304         ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
 305         if (ret)
 306                 goto out;
 307
 308         spin_lock(&tbl->slot_tbl_lock);
 309         nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
 310         spin_unlock(&tbl->slot_tbl_lock);
 311
 312         dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
 313                 tbl, tbl->slots, tbl->max_slots);
 314 out:
 315         dprintk("<-- %s: return %d\n", __func__, ret);
 316         return ret;
 317 }
 318
 319 /*
 320  * nfs4_release_slot_table - release all slot table entries
 321  */
 322 static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
 323 {
 324         nfs4_shrink_slot_table(tbl, 0);
 325 }
 326
 327 /**
 328  * nfs4_shutdown_slot_table - release resources attached to a slot table
 329  * @tbl: slot table to shut down
 330  *
 331  */
 332 void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
 333 {
 334         nfs4_release_slot_table(tbl);
 335         rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
 336 }
 337
 338 /**
 339  * nfs4_setup_slot_table - prepare a stand-alone slot table for use
 340  * @tbl: slot table to set up
 341  * @max_reqs: maximum number of requests allowed
 342  * @queue: name to give RPC wait queue
 343  *
 344  * Returns zero on success, or a negative errno.
 345  */
 346 int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
 347                 const char *queue)
 348 {
 349         nfs4_init_slot_table(tbl, queue);
 350         return nfs4_realloc_slot_table(tbl, max_reqs, 0);
 351 }
 352
 353 static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
 354 {
 355         struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
 356         struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
 357         struct nfs4_slot *slot = pslot;
 358         struct nfs4_slot_table *tbl = slot->table;
 359
 360         if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
 361                 return false;
 362         slot->generation = tbl->generation;
 363         args->sa_slot = slot;
 364         res->sr_timestamp = jiffies;
 365         res->sr_slot = slot;
 366         res->sr_status_flags = 0;
 367         res->sr_status = 1;
 368         return true;
 369 }
 370
 371 static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
 372                 struct nfs4_slot *slot)
 373 {
 374         if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
 375                 return true;
 376         return false;
 377 }
 378
 379 bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
 380                 struct nfs4_slot *slot)
 381 {
 382         if (slot->slot_nr > tbl->max_slotid)
 383                 return false;
 384         return __nfs41_wake_and_assign_slot(tbl, slot);
 385 }
 386
 387 static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
 388 {
 389         struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
 390         if (!IS_ERR(slot)) {
 391                 bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
 392                 if (ret)
 393                         return ret;
 394                 nfs4_free_slot(tbl, slot);
 395         }
 396         return false;
 397 }
 398
 399 void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
 400 {
 401         for (;;) {
 402                 if (!nfs41_try_wake_next_slot_table_entry(tbl))
 403                         break;
 404         }
 405 }
 406
 407 #if defined(CONFIG_NFS_V4_1)
 408
 409 static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
 410                 u32 target_highest_slotid)
 411 {
 412         u32 max_slotid;
 413
 414         max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
 415         if (max_slotid > tbl->server_highest_slotid)
 416                 max_slotid = tbl->server_highest_slotid;
 417         if (max_slotid > tbl->target_highest_slotid)
 418                 max_slotid = tbl->target_highest_slotid;
 419         tbl->max_slotid = max_slotid;
 420         nfs41_wake_slot_table(tbl);
 421 }
 422
 423 /* Update the client's idea of target_highest_slotid */
 424 static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
 425                 u32 target_highest_slotid)
 426 {
 427         if (tbl->target_highest_slotid == target_highest_slotid)
 428                 return;
 429         tbl->target_highest_slotid = target_highest_slotid;
 430         tbl->generation++;
 431 }
 432
 433 void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
 434                 u32 target_highest_slotid)
 435 {
 436         spin_lock(&tbl->slot_tbl_lock);
 437         nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
 438         tbl->d_target_highest_slotid = 0;
 439         tbl->d2_target_highest_slotid = 0;
 440         nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
 441         spin_unlock(&tbl->slot_tbl_lock);
 442 }
 443
 444 static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
 445                 u32 highest_slotid)
 446 {
 447         if (tbl->server_highest_slotid == highest_slotid)
 448                 return;
 449         if (tbl->highest_used_slotid > highest_slotid)
 450                 return;
 451         /* Deallocate slots */
 452         nfs4_shrink_slot_table(tbl, highest_slotid + 1);
 453         tbl->server_highest_slotid = highest_slotid;
 454 }
 455
 456 static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
 457 {
 458         s1 -= s2;
 459         if (s1 == 0)
 460                 return 0;
 461         if (s1 < 0)
 462                 return (s1 - 1) >> 1;
 463         return (s1 + 1) >> 1;
 464 }
 465
 466 static int nfs41_sign_s32(s32 s1)
 467 {
 468         if (s1 > 0)
 469                 return 1;
 470         if (s1 < 0)
 471                 return -1;
 472         return 0;
 473 }
 474
 475 static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
 476 {
 477         if (!s1 || !s2)
 478                 return true;
 479         return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
 480 }
 481
 482 /* Try to eliminate outliers by checking for sharp changes in the
 483  * derivatives and second derivatives
 484  */
 485 static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
 486                 u32 new_target)
 487 {
 488         s32 d_target, d2_target;
 489         bool ret = true;
 490
 491         d_target = nfs41_derivative_target_slotid(new_target,
 492                         tbl->target_highest_slotid);
 493         d2_target = nfs41_derivative_target_slotid(d_target,
 494                         tbl->d_target_highest_slotid);
 495         /* Is first derivative same sign? */
 496         if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
 497                 ret = false;
 498         /* Is second derivative same sign? */
 499         if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
 500                 ret = false;
 501         tbl->d_target_highest_slotid = d_target;
 502         tbl->d2_target_highest_slotid = d2_target;
 503         return ret;
 504 }
 505
 506 void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
 507                 struct nfs4_slot *slot,
 508                 struct nfs4_sequence_res *res)
 509 {
 510         spin_lock(&tbl->slot_tbl_lock);
 511         if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
 512                 nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
 513         if (tbl->generation == slot->generation)
 514                 nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
 515         nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
 516         spin_unlock(&tbl->slot_tbl_lock);
 517 }
 518
 519 static void nfs4_release_session_slot_tables(struct nfs4_session *session)
 520 {
 521         nfs4_release_slot_table(&session->fc_slot_table);
 522         nfs4_release_slot_table(&session->bc_slot_table);
 523 }
 524
 525 /*
 526  * Initialize or reset the forechannel and backchannel tables
 527  */
 528 int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
 529 {
 530         struct nfs4_slot_table *tbl;
 531         int status;
 532
 533         dprintk("--> %s\n", __func__);
 534         /* Fore channel */
 535         tbl = &ses->fc_slot_table;
 536         tbl->session = ses;
 537         status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
 538         if (status || !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */
 539                 return status;
 540         /* Back channel */
 541         tbl = &ses->bc_slot_table;
 542         tbl->session = ses;
 543         status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
 544         if (status && tbl->slots == NULL)
 545                 /* Fore and back channel share a connection so get
 546                  * both slot tables or neither */
 547                 nfs4_release_session_slot_tables(ses);
 548         return status;
 549 }
 550
 551 struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
 552 {
 553         struct nfs4_session *session;
 554
 555         session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
 556         if (!session)
 557                 return NULL;
 558
 559         nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
 560         nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
 561         session->session_state = 1<<NFS4_SESSION_INITING;
 562
 563         session->clp = clp;
 564         return session;
 565 }
 566
 567 static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
 568 {
 569         nfs4_shutdown_slot_table(&session->fc_slot_table);
 570         nfs4_shutdown_slot_table(&session->bc_slot_table);
 571 }
 572
 573 void nfs4_destroy_session(struct nfs4_session *session)
 574 {
 575         struct rpc_xprt *xprt;
 576         struct rpc_cred *cred;
 577
 578         cred = nfs4_get_clid_cred(session->clp);
 579         nfs4_proc_destroy_session(session, cred);
 580         if (cred)
 581                 put_rpccred(cred);
 582
 583         rcu_read_lock();
 584         xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
 585         rcu_read_unlock();
 586         dprintk("%s Destroy backchannel for xprt %p\n",
 587                 __func__, xprt);
 588         xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
 589         nfs4_destroy_session_slot_tables(session);
 590         kfree(session);
 591 }
 592
 593 /*
 594  * With sessions, the client is not marked ready until after a
 595  * successful EXCHANGE_ID and CREATE_SESSION.
 596  *
 597  * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
 598  * other versions of NFS can be tried.
 599  */
 600 static int nfs41_check_session_ready(struct nfs_client *clp)
 601 {
 602         int ret;
 603
 604         if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
 605                 ret = nfs4_client_recover_expired_lease(clp);
 606                 if (ret)
 607                         return ret;
 608         }
 609         if (clp->cl_cons_state < NFS_CS_READY)
 610                 return -EPROTONOSUPPORT;
 611         smp_rmb();
 612         return 0;
 613 }
 614
 615 int nfs4_init_session(struct nfs_client *clp)
 616 {
 617         if (!nfs4_has_session(clp))
 618                 return 0;
 619
 620         clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
 621         return nfs41_check_session_ready(clp);
 622 }
 623
 624 int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
 625 {
 626         struct nfs4_session *session = clp->cl_session;
 627         int ret;
 628
 629         spin_lock(&clp->cl_lock);
 630         if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
 631                 /*
 632                  * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
 633                  * DS lease to be equal to the MDS lease.
 634                  */
 635                 clp->cl_lease_time = lease_time;
 636                 clp->cl_last_renewal = jiffies;
 637         }
 638         spin_unlock(&clp->cl_lock);
 639
 640         ret = nfs41_check_session_ready(clp);
 641         if (ret)
 642                 return ret;
 643         /* Test for the DS role */
 644         if (!is_ds_client(clp))
 645                 return -ENODEV;
 646         return 0;
 647 }
 648 EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
 649
 650 #endif  /* defined(CONFIG_NFS_V4_1) */