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, 1, 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
 182         slot = nfs4_lookup_slot(tbl, slotid);
 183         if (IS_ERR(slot))
 184                 return PTR_ERR(slot);
 185         *seq_nr = slot->seq_nr;
 186         return 0;
 187 }
 188
 189 /*
 190  * nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
 191  *
 192  * Given a slot table, slot id and sequence number, determine if the
 193  * RPC call in question is still in flight. This function is mainly
 194  * intended for use by the callback channel.
 195  */
 196 static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl,
 197                 u32 slotid, u32 seq_nr)
 198 {
 199         u32 cur_seq;
 200         bool ret = false;
 201
 202         spin_lock(&tbl->slot_tbl_lock);
 203         if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
 204             cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
 205                 ret = true;
 206         spin_unlock(&tbl->slot_tbl_lock);
 207         return ret;
 208 }
 209
 210 /*
 211  * nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete
 212  *
 213  * Given a slot table, slot id and sequence number, wait until the
 214  * corresponding RPC call completes. This function is mainly
 215  * intended for use by the callback channel.
 216  */
 217 int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
 218                 u32 slotid, u32 seq_nr,
 219                 unsigned long timeout)
 220 {
 221         if (wait_event_timeout(tbl->slot_waitq,
 222                         !nfs4_slot_seqid_in_use(tbl, slotid, seq_nr),
 223                         timeout) == 0)
 224                 return -ETIMEDOUT;
 225         return 0;
 226 }
 227
 228 /*
 229  * nfs4_alloc_slot - efficiently look for a free slot
 230  *
 231  * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
 232  * If found, we mark the slot as used, update the highest_used_slotid,
 233  * and respectively set up the sequence operation args.
 234  *
 235  * Note: must be called with under the slot_tbl_lock.
 236  */
 237 struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
 238 {
 239         struct nfs4_slot *ret = ERR_PTR(-EBUSY);
 240         u32 slotid;
 241
 242         dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
 243                 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
 244                 tbl->max_slotid + 1);
 245         slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
 246         if (slotid <= tbl->max_slotid) {
 247                 ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
 248                 if (!IS_ERR(ret))
 249                         nfs4_lock_slot(tbl, ret);
 250         }
 251         dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
 252                 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
 253                 !IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
 254         return ret;
 255 }
 256
 257 static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
 258                  u32 max_reqs, u32 ivalue)
 259 {
 260         if (max_reqs <= tbl->max_slots)
 261                 return 0;
 262         if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
 263                 return 0;
 264         return -ENOMEM;
 265 }
 266
 267 static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
 268                 u32 server_highest_slotid,
 269                 u32 ivalue)
 270 {
 271         struct nfs4_slot **p;
 272
 273         nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
 274         p = &tbl->slots;
 275         while (*p) {
 276                 (*p)->seq_nr = ivalue;
 277                 (*p)->interrupted = 0;
 278                 p = &(*p)->next;
 279         }
 280         tbl->highest_used_slotid = NFS4_NO_SLOT;
 281         tbl->target_highest_slotid = server_highest_slotid;
 282         tbl->server_highest_slotid = server_highest_slotid;
 283         tbl->d_target_highest_slotid = 0;
 284         tbl->d2_target_highest_slotid = 0;
 285         tbl->max_slotid = server_highest_slotid;
 286 }
 287
 288 /*
 289  * (re)Initialise a slot table
 290  */
 291 static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
 292                 u32 max_reqs, u32 ivalue)
 293 {
 294         int ret;
 295
 296         dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
 297                 max_reqs, tbl->max_slots);
 298
 299         if (max_reqs > NFS4_MAX_SLOT_TABLE)
 300                 max_reqs = NFS4_MAX_SLOT_TABLE;
 301
 302         ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
 303         if (ret)
 304                 goto out;
 305
 306         spin_lock(&tbl->slot_tbl_lock);
 307         nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
 308         spin_unlock(&tbl->slot_tbl_lock);
 309
 310         dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
 311                 tbl, tbl->slots, tbl->max_slots);
 312 out:
 313         dprintk("<-- %s: return %d\n", __func__, ret);
 314         return ret;
 315 }
 316
 317 /*
 318  * nfs4_release_slot_table - release all slot table entries
 319  */
 320 static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
 321 {
 322         nfs4_shrink_slot_table(tbl, 0);
 323 }
 324
 325 /**
 326  * nfs4_shutdown_slot_table - release resources attached to a slot table
 327  * @tbl: slot table to shut down
 328  *
 329  */
 330 void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
 331 {
 332         nfs4_release_slot_table(tbl);
 333         rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
 334 }
 335
 336 /**
 337  * nfs4_setup_slot_table - prepare a stand-alone slot table for use
 338  * @tbl: slot table to set up
 339  * @max_reqs: maximum number of requests allowed
 340  * @queue: name to give RPC wait queue
 341  *
 342  * Returns zero on success, or a negative errno.
 343  */
 344 int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
 345                 const char *queue)
 346 {
 347         nfs4_init_slot_table(tbl, queue);
 348         return nfs4_realloc_slot_table(tbl, max_reqs, 0);
 349 }
 350
 351 static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
 352 {
 353         struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
 354         struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
 355         struct nfs4_slot *slot = pslot;
 356         struct nfs4_slot_table *tbl = slot->table;
 357
 358         if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
 359                 return false;
 360         slot->generation = tbl->generation;
 361         args->sa_slot = slot;
 362         res->sr_timestamp = jiffies;
 363         res->sr_slot = slot;
 364         res->sr_status_flags = 0;
 365         res->sr_status = 1;
 366         return true;
 367 }
 368
 369 static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
 370                 struct nfs4_slot *slot)
 371 {
 372         if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
 373                 return true;
 374         return false;
 375 }
 376
 377 bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
 378                 struct nfs4_slot *slot)
 379 {
 380         if (slot->slot_nr > tbl->max_slotid)
 381                 return false;
 382         return __nfs41_wake_and_assign_slot(tbl, slot);
 383 }
 384
 385 static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
 386 {
 387         struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
 388         if (!IS_ERR(slot)) {
 389                 bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
 390                 if (ret)
 391                         return ret;
 392                 nfs4_free_slot(tbl, slot);
 393         }
 394         return false;
 395 }
 396
 397 void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
 398 {
 399         for (;;) {
 400                 if (!nfs41_try_wake_next_slot_table_entry(tbl))
 401                         break;
 402         }
 403 }
 404
 405 #if defined(CONFIG_NFS_V4_1)
 406
 407 static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
 408                 u32 target_highest_slotid)
 409 {
 410         u32 max_slotid;
 411
 412         max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
 413         if (max_slotid > tbl->server_highest_slotid)
 414                 max_slotid = tbl->server_highest_slotid;
 415         if (max_slotid > tbl->target_highest_slotid)
 416                 max_slotid = tbl->target_highest_slotid;
 417         tbl->max_slotid = max_slotid;
 418         nfs41_wake_slot_table(tbl);
 419 }
 420
 421 /* Update the client's idea of target_highest_slotid */
 422 static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
 423                 u32 target_highest_slotid)
 424 {
 425         if (tbl->target_highest_slotid == target_highest_slotid)
 426                 return;
 427         tbl->target_highest_slotid = target_highest_slotid;
 428         tbl->generation++;
 429 }
 430
 431 void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
 432                 u32 target_highest_slotid)
 433 {
 434         spin_lock(&tbl->slot_tbl_lock);
 435         nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
 436         tbl->d_target_highest_slotid = 0;
 437         tbl->d2_target_highest_slotid = 0;
 438         nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
 439         spin_unlock(&tbl->slot_tbl_lock);
 440 }
 441
 442 static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
 443                 u32 highest_slotid)
 444 {
 445         if (tbl->server_highest_slotid == highest_slotid)
 446                 return;
 447         if (tbl->highest_used_slotid > highest_slotid)
 448                 return;
 449         /* Deallocate slots */
 450         nfs4_shrink_slot_table(tbl, highest_slotid + 1);
 451         tbl->server_highest_slotid = highest_slotid;
 452 }
 453
 454 static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
 455 {
 456         s1 -= s2;
 457         if (s1 == 0)
 458                 return 0;
 459         if (s1 < 0)
 460                 return (s1 - 1) >> 1;
 461         return (s1 + 1) >> 1;
 462 }
 463
 464 static int nfs41_sign_s32(s32 s1)
 465 {
 466         if (s1 > 0)
 467                 return 1;
 468         if (s1 < 0)
 469                 return -1;
 470         return 0;
 471 }
 472
 473 static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
 474 {
 475         if (!s1 || !s2)
 476                 return true;
 477         return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
 478 }
 479
 480 /* Try to eliminate outliers by checking for sharp changes in the
 481  * derivatives and second derivatives
 482  */
 483 static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
 484                 u32 new_target)
 485 {
 486         s32 d_target, d2_target;
 487         bool ret = true;
 488
 489         d_target = nfs41_derivative_target_slotid(new_target,
 490                         tbl->target_highest_slotid);
 491         d2_target = nfs41_derivative_target_slotid(d_target,
 492                         tbl->d_target_highest_slotid);
 493         /* Is first derivative same sign? */
 494         if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
 495                 ret = false;
 496         /* Is second derivative same sign? */
 497         if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
 498                 ret = false;
 499         tbl->d_target_highest_slotid = d_target;
 500         tbl->d2_target_highest_slotid = d2_target;
 501         return ret;
 502 }
 503
 504 void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
 505                 struct nfs4_slot *slot,
 506                 struct nfs4_sequence_res *res)
 507 {
 508         spin_lock(&tbl->slot_tbl_lock);
 509         if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
 510                 nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
 511         if (tbl->generation == slot->generation)
 512                 nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
 513         nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
 514         spin_unlock(&tbl->slot_tbl_lock);
 515 }
 516
 517 static void nfs4_release_session_slot_tables(struct nfs4_session *session)
 518 {
 519         nfs4_release_slot_table(&session->fc_slot_table);
 520         nfs4_release_slot_table(&session->bc_slot_table);
 521 }
 522
 523 /*
 524  * Initialize or reset the forechannel and backchannel tables
 525  */
 526 int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
 527 {
 528         struct nfs4_slot_table *tbl;
 529         int status;
 530
 531         dprintk("--> %s\n", __func__);
 532         /* Fore channel */
 533         tbl = &ses->fc_slot_table;
 534         tbl->session = ses;
 535         status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
 536         if (status || !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */
 537                 return status;
 538         /* Back channel */
 539         tbl = &ses->bc_slot_table;
 540         tbl->session = ses;
 541         status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
 542         if (status && tbl->slots == NULL)
 543                 /* Fore and back channel share a connection so get
 544                  * both slot tables or neither */
 545                 nfs4_release_session_slot_tables(ses);
 546         return status;
 547 }
 548
 549 struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
 550 {
 551         struct nfs4_session *session;
 552
 553         session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
 554         if (!session)
 555                 return NULL;
 556
 557         nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
 558         nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
 559         session->session_state = 1<<NFS4_SESSION_INITING;
 560
 561         session->clp = clp;
 562         return session;
 563 }
 564
 565 static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
 566 {
 567         nfs4_shutdown_slot_table(&session->fc_slot_table);
 568         nfs4_shutdown_slot_table(&session->bc_slot_table);
 569 }
 570
 571 void nfs4_destroy_session(struct nfs4_session *session)
 572 {
 573         struct rpc_xprt *xprt;
 574         struct rpc_cred *cred;
 575
 576         cred = nfs4_get_clid_cred(session->clp);
 577         nfs4_proc_destroy_session(session, cred);
 578         if (cred)
 579                 put_rpccred(cred);
 580
 581         rcu_read_lock();
 582         xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
 583         rcu_read_unlock();
 584         dprintk("%s Destroy backchannel for xprt %p\n",
 585                 __func__, xprt);
 586         xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
 587         nfs4_destroy_session_slot_tables(session);
 588         kfree(session);
 589 }
 590
 591 /*
 592  * With sessions, the client is not marked ready until after a
 593  * successful EXCHANGE_ID and CREATE_SESSION.
 594  *
 595  * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
 596  * other versions of NFS can be tried.
 597  */
 598 static int nfs41_check_session_ready(struct nfs_client *clp)
 599 {
 600         int ret;
 601
 602         if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
 603                 ret = nfs4_client_recover_expired_lease(clp);
 604                 if (ret)
 605                         return ret;
 606         }
 607         if (clp->cl_cons_state < NFS_CS_READY)
 608                 return -EPROTONOSUPPORT;
 609         smp_rmb();
 610         return 0;
 611 }
 612
 613 int nfs4_init_session(struct nfs_client *clp)
 614 {
 615         if (!nfs4_has_session(clp))
 616                 return 0;
 617
 618         clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
 619         return nfs41_check_session_ready(clp);
 620 }
 621
 622 int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
 623 {
 624         struct nfs4_session *session = clp->cl_session;
 625         int ret;
 626
 627         spin_lock(&clp->cl_lock);
 628         if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
 629                 /*
 630                  * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
 631                  * DS lease to be equal to the MDS lease.
 632                  */
 633                 clp->cl_lease_time = lease_time;
 634                 clp->cl_last_renewal = jiffies;
 635         }
 636         spin_unlock(&clp->cl_lock);
 637
 638         ret = nfs41_check_session_ready(clp);
 639         if (ret)
 640                 return ret;
 641         /* Test for the DS role */
 642         if (!is_ds_client(clp))
 643                 return -ENODEV;
 644         return 0;
 645 }
 646 EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
 647
 648 #endif  /* defined(CONFIG_NFS_V4_1) */