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 /*
  27  * nfs4_shrink_slot_table - free retired slots from the slot table
  28  */
  29 static void nfs4_shrink_slot_table(struct nfs4_slot_table  *tbl, u32 newsize)
  30 {
  31         struct nfs4_slot **p;
  32         if (newsize >= tbl->max_slots)
  33                 return;
  34
  35         p = &tbl->slots;
  36         while (newsize--)
  37                 p = &(*p)->next;
  38         while (*p) {
  39                 struct nfs4_slot *slot = *p;
  40
  41                 *p = slot->next;
  42                 kfree(slot);
  43                 tbl->max_slots--;
  44         }
  45 }
  46
  47 /*
  48  * nfs4_free_slot - free a slot and efficiently update slot table.
  49  *
  50  * freeing a slot is trivially done by clearing its respective bit
  51  * in the bitmap.
  52  * If the freed slotid equals highest_used_slotid we want to update it
  53  * so that the server would be able to size down the slot table if needed,
  54  * otherwise we know that the highest_used_slotid is still in use.
  55  * When updating highest_used_slotid there may be "holes" in the bitmap
  56  * so we need to scan down from highest_used_slotid to 0 looking for the now
  57  * highest slotid in use.
  58  * If none found, highest_used_slotid is set to NFS4_NO_SLOT.
  59  *
  60  * Must be called while holding tbl->slot_tbl_lock
  61  */
  62 void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
  63 {
  64         u32 slotid = slot->slot_nr;
  65
  66         /* clear used bit in bitmap */
  67         __clear_bit(slotid, tbl->used_slots);
  68
  69         /* update highest_used_slotid when it is freed */
  70         if (slotid == tbl->highest_used_slotid) {
  71                 u32 new_max = find_last_bit(tbl->used_slots, slotid);
  72                 if (new_max < slotid)
  73                         tbl->highest_used_slotid = new_max;
  74                 else {
  75                         tbl->highest_used_slotid = NFS4_NO_SLOT;
  76                         nfs4_session_drain_complete(tbl->session, tbl);
  77                 }
  78         }
  79         dprintk("%s: slotid %u highest_used_slotid %d\n", __func__,
  80                 slotid, tbl->highest_used_slotid);
  81 }
  82
  83 static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table  *tbl,
  84                 u32 slotid, u32 seq_init, gfp_t gfp_mask)
  85 {
  86         struct nfs4_slot *slot;
  87
  88         slot = kzalloc(sizeof(*slot), gfp_mask);
  89         if (slot) {
  90                 slot->table = tbl;
  91                 slot->slot_nr = slotid;
  92                 slot->seq_nr = seq_init;
  93         }
  94         return slot;
  95 }
  96
  97 static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table  *tbl,
  98                 u32 slotid, u32 seq_init, gfp_t gfp_mask)
  99 {
 100         struct nfs4_slot **p, *slot;
 101
 102         p = &tbl->slots;
 103         for (;;) {
 104                 if (*p == NULL) {
 105                         *p = nfs4_new_slot(tbl, tbl->max_slots,
 106                                         seq_init, gfp_mask);
 107                         if (*p == NULL)
 108                                 break;
 109                         tbl->max_slots++;
 110                 }
 111                 slot = *p;
 112                 if (slot->slot_nr == slotid)
 113                         return slot;
 114                 p = &slot->next;
 115         }
 116         return ERR_PTR(-ENOMEM);
 117 }
 118
 119 /*
 120  * nfs4_alloc_slot - efficiently look for a free slot
 121  *
 122  * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
 123  * If found, we mark the slot as used, update the highest_used_slotid,
 124  * and respectively set up the sequence operation args.
 125  *
 126  * Note: must be called with under the slot_tbl_lock.
 127  */
 128 struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
 129 {
 130         struct nfs4_slot *ret = ERR_PTR(-EBUSY);
 131         u32 slotid;
 132
 133         dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
 134                 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
 135                 tbl->max_slotid + 1);
 136         slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
 137         if (slotid > tbl->max_slotid)
 138                 goto out;
 139         ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
 140         if (IS_ERR(ret))
 141                 goto out;
 142         __set_bit(slotid, tbl->used_slots);
 143         if (slotid > tbl->highest_used_slotid ||
 144                         tbl->highest_used_slotid == NFS4_NO_SLOT)
 145                 tbl->highest_used_slotid = slotid;
 146         ret->generation = tbl->generation;
 147
 148 out:
 149         dprintk("<-- %s used_slots=%04lx highest_used=%d slotid=%d \n",
 150                 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
 151                 !IS_ERR(ret) ? ret->slot_nr : -1);
 152         return ret;
 153 }
 154
 155 static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
 156                  u32 max_reqs, u32 ivalue)
 157 {
 158         if (max_reqs <= tbl->max_slots)
 159                 return 0;
 160         if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
 161                 return 0;
 162         return -ENOMEM;
 163 }
 164
 165 static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
 166                 u32 server_highest_slotid,
 167                 u32 ivalue)
 168 {
 169         struct nfs4_slot **p;
 170
 171         nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
 172         p = &tbl->slots;
 173         while (*p) {
 174                 (*p)->seq_nr = ivalue;
 175                 (*p)->interrupted = 0;
 176                 p = &(*p)->next;
 177         }
 178         tbl->highest_used_slotid = NFS4_NO_SLOT;
 179         tbl->target_highest_slotid = server_highest_slotid;
 180         tbl->server_highest_slotid = server_highest_slotid;
 181         tbl->d_target_highest_slotid = 0;
 182         tbl->d2_target_highest_slotid = 0;
 183         tbl->max_slotid = server_highest_slotid;
 184 }
 185
 186 /*
 187  * (re)Initialise a slot table
 188  */
 189 static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
 190                 u32 max_reqs, u32 ivalue)
 191 {
 192         int ret;
 193
 194         dprintk("--> %s: max_reqs=%u, tbl->max_slots %d\n", __func__,
 195                 max_reqs, tbl->max_slots);
 196
 197         if (max_reqs > NFS4_MAX_SLOT_TABLE)
 198                 max_reqs = NFS4_MAX_SLOT_TABLE;
 199
 200         ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
 201         if (ret)
 202                 goto out;
 203
 204         spin_lock(&tbl->slot_tbl_lock);
 205         nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
 206         spin_unlock(&tbl->slot_tbl_lock);
 207
 208         dprintk("%s: tbl=%p slots=%p max_slots=%d\n", __func__,
 209                 tbl, tbl->slots, tbl->max_slots);
 210 out:
 211         dprintk("<-- %s: return %d\n", __func__, ret);
 212         return ret;
 213 }
 214
 215 /* Destroy the slot table */
 216 static void nfs4_destroy_slot_tables(struct nfs4_session *session)
 217 {
 218         nfs4_shrink_slot_table(&session->fc_slot_table, 0);
 219         nfs4_shrink_slot_table(&session->bc_slot_table, 0);
 220 }
 221
 222 static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
 223 {
 224         struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
 225         struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
 226         struct nfs4_slot *slot = pslot;
 227         struct nfs4_slot_table *tbl = slot->table;
 228
 229         if (nfs4_session_draining(tbl->session) && !args->sa_privileged)
 230                 return false;
 231         slot->generation = tbl->generation;
 232         args->sa_slot = slot;
 233         res->sr_timestamp = jiffies;
 234         res->sr_slot = slot;
 235         res->sr_status_flags = 0;
 236         res->sr_status = 1;
 237         return true;
 238 }
 239
 240 static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
 241                 struct nfs4_slot *slot)
 242 {
 243         if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
 244                 return true;
 245         return false;
 246 }
 247
 248 bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
 249                 struct nfs4_slot *slot)
 250 {
 251         if (slot->slot_nr > tbl->max_slotid)
 252                 return false;
 253         return __nfs41_wake_and_assign_slot(tbl, slot);
 254 }
 255
 256 static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
 257 {
 258         struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
 259         if (!IS_ERR(slot)) {
 260                 bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
 261                 if (ret)
 262                         return ret;
 263                 nfs4_free_slot(tbl, slot);
 264         }
 265         return false;
 266 }
 267
 268 void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
 269 {
 270         for (;;) {
 271                 if (!nfs41_try_wake_next_slot_table_entry(tbl))
 272                         break;
 273         }
 274 }
 275
 276 static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
 277                 u32 target_highest_slotid)
 278 {
 279         u32 max_slotid;
 280
 281         max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
 282         if (max_slotid > tbl->server_highest_slotid)
 283                 max_slotid = tbl->server_highest_slotid;
 284         if (max_slotid > tbl->target_highest_slotid)
 285                 max_slotid = tbl->target_highest_slotid;
 286         tbl->max_slotid = max_slotid;
 287         nfs41_wake_slot_table(tbl);
 288 }
 289
 290 /* Update the client's idea of target_highest_slotid */
 291 static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
 292                 u32 target_highest_slotid)
 293 {
 294         if (tbl->target_highest_slotid == target_highest_slotid)
 295                 return;
 296         tbl->target_highest_slotid = target_highest_slotid;
 297         tbl->generation++;
 298 }
 299
 300 void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
 301                 u32 target_highest_slotid)
 302 {
 303         spin_lock(&tbl->slot_tbl_lock);
 304         nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
 305         tbl->d_target_highest_slotid = 0;
 306         tbl->d2_target_highest_slotid = 0;
 307         nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
 308         spin_unlock(&tbl->slot_tbl_lock);
 309 }
 310
 311 static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
 312                 u32 highest_slotid)
 313 {
 314         if (tbl->server_highest_slotid == highest_slotid)
 315                 return;
 316         if (tbl->highest_used_slotid > highest_slotid)
 317                 return;
 318         /* Deallocate slots */
 319         nfs4_shrink_slot_table(tbl, highest_slotid + 1);
 320         tbl->server_highest_slotid = highest_slotid;
 321 }
 322
 323 static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
 324 {
 325         s1 -= s2;
 326         if (s1 == 0)
 327                 return 0;
 328         if (s1 < 0)
 329                 return (s1 - 1) >> 1;
 330         return (s1 + 1) >> 1;
 331 }
 332
 333 static int nfs41_sign_s32(s32 s1)
 334 {
 335         if (s1 > 0)
 336                 return 1;
 337         if (s1 < 0)
 338                 return -1;
 339         return 0;
 340 }
 341
 342 static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
 343 {
 344         if (!s1 || !s2)
 345                 return true;
 346         return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
 347 }
 348
 349 /* Try to eliminate outliers by checking for sharp changes in the
 350  * derivatives and second derivatives
 351  */
 352 static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
 353                 u32 new_target)
 354 {
 355         s32 d_target, d2_target;
 356         bool ret = true;
 357
 358         d_target = nfs41_derivative_target_slotid(new_target,
 359                         tbl->target_highest_slotid);
 360         d2_target = nfs41_derivative_target_slotid(d_target,
 361                         tbl->d_target_highest_slotid);
 362         /* Is first derivative same sign? */
 363         if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
 364                 ret = false;
 365         /* Is second derivative same sign? */
 366         if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
 367                 ret = false;
 368         tbl->d_target_highest_slotid = d_target;
 369         tbl->d2_target_highest_slotid = d2_target;
 370         return ret;
 371 }
 372
 373 void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
 374                 struct nfs4_slot *slot,
 375                 struct nfs4_sequence_res *res)
 376 {
 377         spin_lock(&tbl->slot_tbl_lock);
 378         if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
 379                 nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
 380         if (tbl->generation == slot->generation)
 381                 nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
 382         nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
 383         spin_unlock(&tbl->slot_tbl_lock);
 384 }
 385
 386 /*
 387  * Initialize or reset the forechannel and backchannel tables
 388  */
 389 int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
 390 {
 391         struct nfs4_slot_table *tbl;
 392         int status;
 393
 394         dprintk("--> %s\n", __func__);
 395         /* Fore channel */
 396         tbl = &ses->fc_slot_table;
 397         tbl->session = ses;
 398         status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
 399         if (status) /* -ENOMEM */
 400                 return status;
 401         /* Back channel */
 402         tbl = &ses->bc_slot_table;
 403         tbl->session = ses;
 404         status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
 405         if (status && tbl->slots == NULL)
 406                 /* Fore and back channel share a connection so get
 407                  * both slot tables or neither */
 408                 nfs4_destroy_slot_tables(ses);
 409         return status;
 410 }
 411
 412 struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
 413 {
 414         struct nfs4_session *session;
 415         struct nfs4_slot_table *tbl;
 416
 417         session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
 418         if (!session)
 419                 return NULL;
 420
 421         tbl = &session->fc_slot_table;
 422         tbl->highest_used_slotid = NFS4_NO_SLOT;
 423         spin_lock_init(&tbl->slot_tbl_lock);
 424         rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, "ForeChannel Slot table");
 425         init_completion(&tbl->complete);
 426
 427         tbl = &session->bc_slot_table;
 428         tbl->highest_used_slotid = NFS4_NO_SLOT;
 429         spin_lock_init(&tbl->slot_tbl_lock);
 430         rpc_init_wait_queue(&tbl->slot_tbl_waitq, "BackChannel Slot table");
 431         init_completion(&tbl->complete);
 432
 433         session->session_state = 1<<NFS4_SESSION_INITING;
 434
 435         session->clp = clp;
 436         return session;
 437 }
 438
 439 void nfs4_destroy_session(struct nfs4_session *session)
 440 {
 441         struct rpc_xprt *xprt;
 442         struct rpc_cred *cred;
 443
 444         cred = nfs4_get_exchange_id_cred(session->clp);
 445         nfs4_proc_destroy_session(session, cred);
 446         if (cred)
 447                 put_rpccred(cred);
 448
 449         rcu_read_lock();
 450         xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
 451         rcu_read_unlock();
 452         dprintk("%s Destroy backchannel for xprt %p\n",
 453                 __func__, xprt);
 454         xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
 455         nfs4_destroy_slot_tables(session);
 456         kfree(session);
 457 }
 458
 459 /*
 460  * With sessions, the client is not marked ready until after a
 461  * successful EXCHANGE_ID and CREATE_SESSION.
 462  *
 463  * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
 464  * other versions of NFS can be tried.
 465  */
 466 static int nfs41_check_session_ready(struct nfs_client *clp)
 467 {
 468         int ret;
 469
 470         if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
 471                 ret = nfs4_client_recover_expired_lease(clp);
 472                 if (ret)
 473                         return ret;
 474         }
 475         if (clp->cl_cons_state < NFS_CS_READY)
 476                 return -EPROTONOSUPPORT;
 477         smp_rmb();
 478         return 0;
 479 }
 480
 481 int nfs4_init_session(struct nfs_server *server)
 482 {
 483         struct nfs_client *clp = server->nfs_client;
 484         struct nfs4_session *session;
 485         unsigned int target_max_rqst_sz = NFS_MAX_FILE_IO_SIZE;
 486         unsigned int target_max_resp_sz = NFS_MAX_FILE_IO_SIZE;
 487
 488         if (!nfs4_has_session(clp))
 489                 return 0;
 490
 491         if (server->rsize != 0)
 492                 target_max_resp_sz = server->rsize;
 493         target_max_resp_sz += nfs41_maxread_overhead;
 494
 495         if (server->wsize != 0)
 496                 target_max_rqst_sz = server->wsize;
 497         target_max_rqst_sz += nfs41_maxwrite_overhead;
 498
 499         session = clp->cl_session;
 500         spin_lock(&clp->cl_lock);
 501         if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
 502                 /* Initialise targets and channel attributes */
 503                 session->fc_target_max_rqst_sz = target_max_rqst_sz;
 504                 session->fc_attrs.max_rqst_sz = target_max_rqst_sz;
 505                 session->fc_target_max_resp_sz = target_max_resp_sz;
 506                 session->fc_attrs.max_resp_sz = target_max_resp_sz;
 507         } else {
 508                 /* Just adjust the targets */
 509                 if (target_max_rqst_sz > session->fc_target_max_rqst_sz) {
 510                         session->fc_target_max_rqst_sz = target_max_rqst_sz;
 511                         set_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
 512                 }
 513                 if (target_max_resp_sz > session->fc_target_max_resp_sz) {
 514                         session->fc_target_max_resp_sz = target_max_resp_sz;
 515                         set_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
 516                 }
 517         }
 518         spin_unlock(&clp->cl_lock);
 519
 520         if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state))
 521                 nfs4_schedule_lease_recovery(clp);
 522
 523         return nfs41_check_session_ready(clp);
 524 }
 525
 526 int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
 527 {
 528         struct nfs4_session *session = clp->cl_session;
 529         int ret;
 530
 531         spin_lock(&clp->cl_lock);
 532         if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
 533                 /*
 534                  * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
 535                  * DS lease to be equal to the MDS lease.
 536                  */
 537                 clp->cl_lease_time = lease_time;
 538                 clp->cl_last_renewal = jiffies;
 539         }
 540         spin_unlock(&clp->cl_lock);
 541
 542         ret = nfs41_check_session_ready(clp);
 543         if (ret)
 544                 return ret;
 545         /* Test for the DS role */
 546         if (!is_ds_client(clp))
 547                 return -ENODEV;
 548         return 0;
 549 }
 550 EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
 551
 552