lustre/ptlrpc/import.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2016, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  *
  32  * lustre/ptlrpc/import.c
  33  *
  34  * Author: Mike Shaver <shaver@clusterfs.com>
  35  */
  36
  37 #define DEBUG_SUBSYSTEM S_RPC
  38
  39 #include <linux/kthread.h>
  40 #include <obd_support.h>
  41 #include <lustre_ha.h>
  42 #include <lustre_net.h>
  43 #include <lustre_import.h>
  44 #include <lustre_export.h>
  45 #include <obd.h>
  46 #include <obd_cksum.h>
  47 #include <obd_class.h>
  48
  49 #include "ptlrpc_internal.h"
  50
  51 struct ptlrpc_connect_async_args {
  52          __u64 pcaa_peer_committed;
  53         int pcaa_initial_connect;
  54 };
  55
  56 /**
  57  * Updates import \a imp current state to provided \a state value
  58  * Helper function. Must be called under imp_lock.
  59  */
  60 static void __import_set_state(struct obd_import *imp,
  61                                enum lustre_imp_state state)
  62 {
  63         switch (state) {
  64         case LUSTRE_IMP_CLOSED:
  65         case LUSTRE_IMP_NEW:
  66         case LUSTRE_IMP_DISCON:
  67         case LUSTRE_IMP_CONNECTING:
  68                 break;
  69         case LUSTRE_IMP_REPLAY_WAIT:
  70                 imp->imp_replay_state = LUSTRE_IMP_REPLAY_LOCKS;
  71                 break;
  72         default:
  73                 imp->imp_replay_state = LUSTRE_IMP_REPLAY;
  74         }
  75         imp->imp_state = state;
  76         imp->imp_state_hist[imp->imp_state_hist_idx].ish_state = state;
  77         imp->imp_state_hist[imp->imp_state_hist_idx].ish_time =
  78                 ktime_get_real_seconds();
  79         imp->imp_state_hist_idx = (imp->imp_state_hist_idx + 1) %
  80                 IMP_STATE_HIST_LEN;
  81 }
  82
  83 /* A CLOSED import should remain so. */
  84 #define IMPORT_SET_STATE_NOLOCK(imp, state)                                    \
  85 do {                                                                           \
  86         if (imp->imp_state != LUSTRE_IMP_CLOSED) {                             \
  87                CDEBUG(D_HA, "%p %s: changing import state from %s to %s\n",    \
  88                       imp, obd2cli_tgt(imp->imp_obd),                          \
  89                       ptlrpc_import_state_name(imp->imp_state),                \
  90                       ptlrpc_import_state_name(state));                        \
  91                __import_set_state(imp, state);                                 \
  92         }                                                                      \
  93 } while(0)
  94
  95 #define IMPORT_SET_STATE(imp, state)                                    \
  96 do {                                                                    \
  97         spin_lock(&imp->imp_lock);                                      \
  98         IMPORT_SET_STATE_NOLOCK(imp, state);                            \
  99         spin_unlock(&imp->imp_lock);                                    \
 100 } while(0)
 101
 102 void ptlrpc_import_enter_resend(struct obd_import *imp)
 103 {
 104         IMPORT_SET_STATE(imp, LUSTRE_IMP_RECOVER);
 105 }
 106 EXPORT_SYMBOL(ptlrpc_import_enter_resend);
 107
 108
 109 static int ptlrpc_connect_interpret(const struct lu_env *env,
 110                                     struct ptlrpc_request *request,
 111                                     void * data, int rc);
 112 int ptlrpc_import_recovery_state_machine(struct obd_import *imp);
 113
 114 /* Only this function is allowed to change the import state when it is
 115  * CLOSED. I would rather refcount the import and free it after
 116  * disconnection like we do with exports. To do that, the client_obd
 117  * will need to save the peer info somewhere other than in the import,
 118  * though. */
 119 int ptlrpc_init_import(struct obd_import *imp)
 120 {
 121         spin_lock(&imp->imp_lock);
 122
 123         imp->imp_generation++;
 124         imp->imp_state =  LUSTRE_IMP_NEW;
 125
 126         spin_unlock(&imp->imp_lock);
 127
 128         return 0;
 129 }
 130 EXPORT_SYMBOL(ptlrpc_init_import);
 131
 132 #define UUID_STR "_UUID"
 133 void deuuidify(char *uuid, const char *prefix, char **uuid_start, int *uuid_len)
 134 {
 135         *uuid_start = !prefix || strncmp(uuid, prefix, strlen(prefix))
 136                 ? uuid : uuid + strlen(prefix);
 137
 138         *uuid_len = strlen(*uuid_start);
 139
 140         if (*uuid_len < strlen(UUID_STR))
 141                 return;
 142
 143         if (!strncmp(*uuid_start + *uuid_len - strlen(UUID_STR),
 144                     UUID_STR, strlen(UUID_STR)))
 145                 *uuid_len -= strlen(UUID_STR);
 146 }
 147
 148 /**
 149  * Returns true if import was FULL, false if import was already not
 150  * connected.
 151  * @imp - import to be disconnected
 152  * @conn_cnt - connection count (epoch) of the request that timed out
 153  *             and caused the disconnection.  In some cases, multiple
 154  *             inflight requests can fail to a single target (e.g. OST
 155  *             bulk requests) and if one has already caused a reconnection
 156  *             (increasing the import->conn_cnt) the older failure should
 157  *             not also cause a reconnection.  If zero it forces a reconnect.
 158  */
 159 int ptlrpc_set_import_discon(struct obd_import *imp, __u32 conn_cnt)
 160 {
 161         int rc = 0;
 162
 163         spin_lock(&imp->imp_lock);
 164
 165         if (imp->imp_state == LUSTRE_IMP_FULL &&
 166             (conn_cnt == 0 || conn_cnt == imp->imp_conn_cnt)) {
 167                 char *target_start;
 168                 int   target_len;
 169
 170                 deuuidify(obd2cli_tgt(imp->imp_obd), NULL,
 171                           &target_start, &target_len);
 172
 173                 if (imp->imp_replayable) {
 174                         LCONSOLE_WARN("%s: Connection to %.*s (at %s) was "
 175                                "lost; in progress operations using this "
 176                                "service will wait for recovery to complete\n",
 177                                imp->imp_obd->obd_name, target_len, target_start,
 178                                libcfs_nid2str(imp->imp_connection->c_peer.nid));
 179                 } else {
 180                         LCONSOLE_ERROR_MSG(0x166, "%s: Connection to "
 181                                "%.*s (at %s) was lost; in progress "
 182                                "operations using this service will fail\n",
 183                                imp->imp_obd->obd_name,
 184                                target_len, target_start,
 185                                libcfs_nid2str(imp->imp_connection->c_peer.nid));
 186                 }
 187                 IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_DISCON);
 188                 spin_unlock(&imp->imp_lock);
 189
 190                 if (obd_dump_on_timeout)
 191                         libcfs_debug_dumplog();
 192
 193                 obd_import_event(imp->imp_obd, imp, IMP_EVENT_DISCON);
 194                 rc = 1;
 195         } else {
 196                 spin_unlock(&imp->imp_lock);
 197                 CDEBUG(D_HA, "%s: import %p already %s (conn %u, was %u): %s\n",
 198                        imp->imp_client->cli_name, imp,
 199                        (imp->imp_state == LUSTRE_IMP_FULL &&
 200                         imp->imp_conn_cnt > conn_cnt) ?
 201                        "reconnected" : "not connected", imp->imp_conn_cnt,
 202                        conn_cnt, ptlrpc_import_state_name(imp->imp_state));
 203         }
 204
 205         return rc;
 206 }
 207
 208 /* Must be called with imp_lock held! */
 209 static void ptlrpc_deactivate_and_unlock_import(struct obd_import *imp)
 210 {
 211         ENTRY;
 212         assert_spin_locked(&imp->imp_lock);
 213
 214         CDEBUG(D_HA, "setting import %s INVALID\n", obd2cli_tgt(imp->imp_obd));
 215         imp->imp_invalid = 1;
 216         imp->imp_generation++;
 217         spin_unlock(&imp->imp_lock);
 218
 219         ptlrpc_abort_inflight(imp);
 220         obd_import_event(imp->imp_obd, imp, IMP_EVENT_INACTIVE);
 221
 222         EXIT;
 223 }
 224
 225 /*
 226  * This acts as a barrier; all existing requests are rejected, and
 227  * no new requests will be accepted until the import is valid again.
 228  */
 229 void ptlrpc_deactivate_import(struct obd_import *imp)
 230 {
 231         spin_lock(&imp->imp_lock);
 232         ptlrpc_deactivate_and_unlock_import(imp);
 233 }
 234 EXPORT_SYMBOL(ptlrpc_deactivate_import);
 235
 236 static time64_t ptlrpc_inflight_deadline(struct ptlrpc_request *req,
 237                                          time64_t now)
 238 {
 239         time64_t dl;
 240
 241         if (!(((req->rq_phase == RQ_PHASE_RPC) && !req->rq_waiting) ||
 242               (req->rq_phase == RQ_PHASE_BULK) ||
 243               (req->rq_phase == RQ_PHASE_NEW)))
 244                 return 0;
 245
 246         if (req->rq_timedout)
 247                 return 0;
 248
 249         if (req->rq_phase == RQ_PHASE_NEW)
 250                 dl = req->rq_sent;
 251         else
 252                 dl = req->rq_deadline;
 253
 254         if (dl <= now)
 255                 return 0;
 256
 257         return dl - now;
 258 }
 259
 260 static unsigned int ptlrpc_inflight_timeout(struct obd_import *imp)
 261 {
 262         time64_t now = ktime_get_real_seconds();
 263         struct list_head *tmp, *n;
 264         struct ptlrpc_request *req;
 265         time64_t timeout = 0;
 266
 267         spin_lock(&imp->imp_lock);
 268         list_for_each_safe(tmp, n, &imp->imp_sending_list) {
 269                 req = list_entry(tmp, struct ptlrpc_request, rq_list);
 270                 timeout = max(ptlrpc_inflight_deadline(req, now), timeout);
 271         }
 272         spin_unlock(&imp->imp_lock);
 273         return timeout;
 274 }
 275
 276 /**
 277  * This function will invalidate the import, if necessary, then block
 278  * for all the RPC completions, and finally notify the obd to
 279  * invalidate its state (ie cancel locks, clear pending requests,
 280  * etc).
 281  */
 282 void ptlrpc_invalidate_import(struct obd_import *imp)
 283 {
 284         struct list_head *tmp, *n;
 285         struct ptlrpc_request *req;
 286         struct l_wait_info lwi;
 287         time64_t timeout;
 288         int rc;
 289
 290         atomic_inc(&imp->imp_inval_count);
 291
 292         if (!imp->imp_invalid || imp->imp_obd->obd_no_recov)
 293                 ptlrpc_deactivate_import(imp);
 294
 295         CFS_FAIL_TIMEOUT(OBD_FAIL_MGS_CONNECT_NET, 3 * cfs_fail_val / 2);
 296         LASSERT(imp->imp_invalid);
 297
 298         /* Wait forever until inflight == 0. We really can't do it another
 299          * way because in some cases we need to wait for very long reply
 300          * unlink. We can't do anything before that because there is really
 301          * no guarantee that some rdma transfer is not in progress right now. */
 302         do {
 303                 long timeout_jiffies;
 304
 305                 /* Calculate max timeout for waiting on rpcs to error
 306                  * out. Use obd_timeout if calculated value is smaller
 307                  * than it.
 308                  */
 309                 if (!OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_LONG_REPL_UNLINK)) {
 310                         timeout = ptlrpc_inflight_timeout(imp);
 311                         timeout += timeout / 3;
 312
 313                         if (timeout == 0)
 314                                 timeout = obd_timeout;
 315                 } else {
 316                         /* decrease the interval to increase race condition */
 317                         timeout = 1;
 318                 }
 319
 320                 CDEBUG(D_RPCTRACE, "Sleeping %llds for inflight to error out\n",
 321                        timeout);
 322
 323                 /* Wait for all requests to error out and call completion
 324                  * callbacks. Cap it at obd_timeout -- these should all
 325                  * have been locally cancelled by ptlrpc_abort_inflight.
 326                  */
 327                 timeout_jiffies = max_t(long, cfs_time_seconds(timeout), 1);
 328                 lwi = LWI_TIMEOUT_INTERVAL(timeout_jiffies,
 329                                            (timeout > 1) ? cfs_time_seconds(1) :
 330                                                            cfs_time_seconds(1) / 2,
 331                                                            NULL, NULL);
 332                 rc = l_wait_event(imp->imp_recovery_waitq,
 333                                   (atomic_read(&imp->imp_inflight) == 0),
 334                                   &lwi);
 335                 if (rc) {
 336                         const char *cli_tgt = obd2cli_tgt(imp->imp_obd);
 337
 338                         CERROR("%s: rc = %d waiting for callback (%d != 0)\n",
 339                                cli_tgt, rc, atomic_read(&imp->imp_inflight));
 340
 341                         spin_lock(&imp->imp_lock);
 342                         if (atomic_read(&imp->imp_inflight) == 0) {
 343                                 int count = atomic_read(&imp->imp_unregistering);
 344
 345                                 /* We know that "unregistering" rpcs only can
 346                                  * survive in sending or delaying lists (they
 347                                  * maybe waiting for long reply unlink in
 348                                  * sluggish nets). Let's check this. If there
 349                                  * is no inflight and unregistering != 0, this
 350                                  * is bug. */
 351                                 LASSERTF(count == 0, "Some RPCs are still "
 352                                          "unregistering: %d\n", count);
 353
 354                                 /* Let's save one loop as soon as inflight have
 355                                  * dropped to zero. No new inflights possible at
 356                                  * this point. */
 357                                 rc = 0;
 358                         } else {
 359                                 list_for_each_safe(tmp, n,
 360                                                    &imp->imp_sending_list) {
 361                                         req = list_entry(tmp,
 362                                                          struct ptlrpc_request,
 363                                                          rq_list);
 364                                         DEBUG_REQ(D_ERROR, req,
 365                                                   "still on sending list");
 366                                 }
 367                                 list_for_each_safe(tmp, n,
 368                                                    &imp->imp_delayed_list) {
 369                                         req = list_entry(tmp,
 370                                                          struct ptlrpc_request,
 371                                                          rq_list);
 372                                         DEBUG_REQ(D_ERROR, req,
 373                                                   "still on delayed list");
 374                                 }
 375
 376                                 CERROR("%s: Unregistering RPCs found (%d). "
 377                                        "Network is sluggish? Waiting them "
 378                                        "to error out.\n", cli_tgt,
 379                                        atomic_read(&imp->imp_unregistering));
 380                         }
 381                         spin_unlock(&imp->imp_lock);
 382                 }
 383         } while (rc != 0);
 384
 385         /*
 386          * Let's additionally check that no new rpcs added to import in
 387          * "invalidate" state.
 388          */
 389         LASSERT(atomic_read(&imp->imp_inflight) == 0);
 390         obd_import_event(imp->imp_obd, imp, IMP_EVENT_INVALIDATE);
 391         sptlrpc_import_flush_all_ctx(imp);
 392
 393         atomic_dec(&imp->imp_inval_count);
 394         wake_up_all(&imp->imp_recovery_waitq);
 395 }
 396 EXPORT_SYMBOL(ptlrpc_invalidate_import);
 397
 398 /* unset imp_invalid */
 399 void ptlrpc_activate_import(struct obd_import *imp)
 400 {
 401         struct obd_device *obd = imp->imp_obd;
 402
 403         spin_lock(&imp->imp_lock);
 404         if (imp->imp_deactive != 0) {
 405                 spin_unlock(&imp->imp_lock);
 406                 return;
 407         }
 408
 409         imp->imp_invalid = 0;
 410         spin_unlock(&imp->imp_lock);
 411         obd_import_event(obd, imp, IMP_EVENT_ACTIVE);
 412 }
 413 EXPORT_SYMBOL(ptlrpc_activate_import);
 414
 415 void ptlrpc_pinger_force(struct obd_import *imp)
 416 {
 417         CDEBUG(D_HA, "%s: waking up pinger s:%s\n", obd2cli_tgt(imp->imp_obd),
 418                ptlrpc_import_state_name(imp->imp_state));
 419
 420         spin_lock(&imp->imp_lock);
 421         imp->imp_force_verify = 1;
 422         spin_unlock(&imp->imp_lock);
 423
 424         if (imp->imp_state != LUSTRE_IMP_CONNECTING)
 425                 ptlrpc_pinger_wake_up();
 426 }
 427 EXPORT_SYMBOL(ptlrpc_pinger_force);
 428
 429 void ptlrpc_fail_import(struct obd_import *imp, __u32 conn_cnt)
 430 {
 431         ENTRY;
 432
 433         LASSERT(!imp->imp_dlm_fake);
 434
 435         if (ptlrpc_set_import_discon(imp, conn_cnt)) {
 436                 if (!imp->imp_replayable) {
 437                         CDEBUG(D_HA, "import %s@%s for %s not replayable, "
 438                                "auto-deactivating\n",
 439                                obd2cli_tgt(imp->imp_obd),
 440                                imp->imp_connection->c_remote_uuid.uuid,
 441                                imp->imp_obd->obd_name);
 442                         ptlrpc_deactivate_import(imp);
 443                 }
 444
 445                 ptlrpc_pinger_force(imp);
 446         }
 447         EXIT;
 448 }
 449
 450 int ptlrpc_reconnect_import(struct obd_import *imp)
 451 {
 452 #ifdef ENABLE_PINGER
 453         long timeout_jiffies = cfs_time_seconds(obd_timeout);
 454         struct l_wait_info lwi;
 455         int rc;
 456
 457         ptlrpc_pinger_force(imp);
 458
 459         CDEBUG(D_HA, "%s: recovery started, waiting %u seconds\n",
 460                obd2cli_tgt(imp->imp_obd), obd_timeout);
 461
 462         lwi = LWI_TIMEOUT(timeout_jiffies, NULL, NULL);
 463         rc = l_wait_event(imp->imp_recovery_waitq,
 464                           !ptlrpc_import_in_recovery(imp), &lwi);
 465         CDEBUG(D_HA, "%s: recovery finished s:%s\n", obd2cli_tgt(imp->imp_obd),
 466                ptlrpc_import_state_name(imp->imp_state));
 467         return rc;
 468 #else
 469         ptlrpc_set_import_discon(imp, 0);
 470         /* Force a new connect attempt */
 471         ptlrpc_invalidate_import(imp);
 472         /* Do a fresh connect next time by zeroing the handle */
 473         ptlrpc_disconnect_import(imp, 1);
 474         /* Wait for all invalidate calls to finish */
 475         if (atomic_read(&imp->imp_inval_count) > 0) {
 476                 struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
 477                 int rc;
 478
 479                 rc = l_wait_event(imp->imp_recovery_waitq,
 480                                   (atomic_read(&imp->imp_inval_count) == 0),
 481                                   &lwi);
 482                 if (rc)
 483                         CERROR("Interrupted, inval=%d\n",
 484                                atomic_read(&imp->imp_inval_count));
 485         }
 486
 487         /* Allow reconnect attempts */
 488         imp->imp_obd->obd_no_recov = 0;
 489         /* Remove 'invalid' flag */
 490         ptlrpc_activate_import(imp);
 491         /* Attempt a new connect */
 492         ptlrpc_recover_import(imp, NULL, 0);
 493         return 0;
 494 #endif
 495 }
 496 EXPORT_SYMBOL(ptlrpc_reconnect_import);
 497
 498 /**
 499  * Connection on import \a imp is changed to another one (if more than one is
 500  * present). We typically chose connection that we have not tried to connect to
 501  * the longest
 502  */
 503 static int import_select_connection(struct obd_import *imp)
 504 {
 505         struct obd_import_conn *imp_conn = NULL, *conn;
 506         struct obd_export *dlmexp;
 507         char *target_start;
 508         int target_len, tried_all = 1;
 509         ENTRY;
 510
 511         spin_lock(&imp->imp_lock);
 512
 513         if (list_empty(&imp->imp_conn_list)) {
 514                 CERROR("%s: no connections available\n",
 515                        imp->imp_obd->obd_name);
 516                 spin_unlock(&imp->imp_lock);
 517                 RETURN(-EINVAL);
 518         }
 519
 520         list_for_each_entry(conn, &imp->imp_conn_list, oic_item) {
 521                 CDEBUG(D_HA, "%s: connect to NID %s last attempt %llu\n",
 522                        imp->imp_obd->obd_name,
 523                        libcfs_nid2str(conn->oic_conn->c_peer.nid),
 524                        conn->oic_last_attempt);
 525
 526                 /* If we have not tried this connection since
 527                    the last successful attempt, go with this one */
 528                 if ((conn->oic_last_attempt == 0) ||
 529                     cfs_time_beforeq_64(conn->oic_last_attempt,
 530                                        imp->imp_last_success_conn)) {
 531                         imp_conn = conn;
 532                         tried_all = 0;
 533                         break;
 534                 }
 535
 536                 /* If all of the connections have already been tried
 537                    since the last successful connection; just choose the
 538                    least recently used */
 539                 if (!imp_conn)
 540                         imp_conn = conn;
 541                 else if (cfs_time_before_64(conn->oic_last_attempt,
 542                                             imp_conn->oic_last_attempt))
 543                         imp_conn = conn;
 544         }
 545
 546         /* if not found, simply choose the current one */
 547         if (!imp_conn || imp->imp_force_reconnect) {
 548                 LASSERT(imp->imp_conn_current);
 549                 imp_conn = imp->imp_conn_current;
 550                 tried_all = 0;
 551         }
 552         LASSERT(imp_conn->oic_conn);
 553
 554         /* If we've tried everything, and we're back to the beginning of the
 555            list, increase our timeout and try again. It will be reset when
 556            we do finally connect. (FIXME: really we should wait for all network
 557            state associated with the last connection attempt to drain before
 558            trying to reconnect on it.) */
 559         if (tried_all && (imp->imp_conn_list.next == &imp_conn->oic_item)) {
 560                 struct adaptive_timeout *at = &imp->imp_at.iat_net_latency;
 561                 if (at_get(at) < CONNECTION_SWITCH_MAX) {
 562                         at_measured(at, at_get(at) + CONNECTION_SWITCH_INC);
 563                         if (at_get(at) > CONNECTION_SWITCH_MAX)
 564                                 at_reset(at, CONNECTION_SWITCH_MAX);
 565                 }
 566                 LASSERT(imp_conn->oic_last_attempt);
 567                 CDEBUG(D_HA, "%s: tried all connections, increasing latency "
 568                         "to %ds\n", imp->imp_obd->obd_name, at_get(at));
 569         }
 570
 571         imp_conn->oic_last_attempt = cfs_time_current_64();
 572
 573         /* switch connection, don't mind if it's same as the current one */
 574         if (imp->imp_connection)
 575                 ptlrpc_connection_put(imp->imp_connection);
 576         imp->imp_connection = ptlrpc_connection_addref(imp_conn->oic_conn);
 577
 578         dlmexp =  class_conn2export(&imp->imp_dlm_handle);
 579         LASSERT(dlmexp != NULL);
 580         if (dlmexp->exp_connection)
 581                 ptlrpc_connection_put(dlmexp->exp_connection);
 582         dlmexp->exp_connection = ptlrpc_connection_addref(imp_conn->oic_conn);
 583         class_export_put(dlmexp);
 584
 585         if (imp->imp_conn_current != imp_conn) {
 586                 if (imp->imp_conn_current) {
 587                         deuuidify(obd2cli_tgt(imp->imp_obd), NULL,
 588                                   &target_start, &target_len);
 589
 590                         CDEBUG(D_HA, "%s: Connection changing to"
 591                                " %.*s (at %s)\n",
 592                                imp->imp_obd->obd_name,
 593                                target_len, target_start,
 594                                libcfs_nid2str(imp_conn->oic_conn->c_peer.nid));
 595                 }
 596
 597                 imp->imp_conn_current = imp_conn;
 598         }
 599
 600         CDEBUG(D_HA, "%s: import %p using connection %s/%s\n",
 601                imp->imp_obd->obd_name, imp, imp_conn->oic_uuid.uuid,
 602                libcfs_nid2str(imp_conn->oic_conn->c_peer.nid));
 603
 604         spin_unlock(&imp->imp_lock);
 605
 606         RETURN(0);
 607 }
 608
 609 /*
 610  * must be called under imp_lock
 611  */
 612 static int ptlrpc_first_transno(struct obd_import *imp, __u64 *transno)
 613 {
 614         struct ptlrpc_request   *req;
 615         struct list_head        *tmp;
 616
 617         /* The requests in committed_list always have smaller transnos than
 618          * the requests in replay_list */
 619         if (!list_empty(&imp->imp_committed_list)) {
 620                 tmp = imp->imp_committed_list.next;
 621                 req = list_entry(tmp, struct ptlrpc_request, rq_replay_list);
 622                 *transno = req->rq_transno;
 623                 if (req->rq_transno == 0) {
 624                         DEBUG_REQ(D_ERROR, req, "zero transno in committed_list");
 625                         LBUG();
 626                 }
 627                 return 1;
 628         }
 629         if (!list_empty(&imp->imp_replay_list)) {
 630                 tmp = imp->imp_replay_list.next;
 631                 req = list_entry(tmp, struct ptlrpc_request, rq_replay_list);
 632                 *transno = req->rq_transno;
 633                 if (req->rq_transno == 0) {
 634                         DEBUG_REQ(D_ERROR, req, "zero transno in replay_list");
 635                         LBUG();
 636                 }
 637                 return 1;
 638         }
 639         return 0;
 640 }
 641
 642 /**
 643  * Attempt to (re)connect import \a imp. This includes all preparations,
 644  * initializing CONNECT RPC request and passing it to ptlrpcd for
 645  * actual sending.
 646  * Returns 0 on success or error code.
 647  */
 648 int ptlrpc_connect_import(struct obd_import *imp)
 649 {
 650         struct obd_device *obd = imp->imp_obd;
 651         int initial_connect = 0;
 652         int set_transno = 0;
 653         __u64 committed_before_reconnect = 0;
 654         struct ptlrpc_request *request;
 655         char *bufs[] = { NULL,
 656                          obd2cli_tgt(imp->imp_obd),
 657                          obd->obd_uuid.uuid,
 658                          (char *)&imp->imp_dlm_handle,
 659                          (char *)&imp->imp_connect_data };
 660         struct ptlrpc_connect_async_args *aa;
 661         int rc;
 662         ENTRY;
 663
 664         spin_lock(&imp->imp_lock);
 665         if (imp->imp_state == LUSTRE_IMP_CLOSED) {
 666                 spin_unlock(&imp->imp_lock);
 667                 CERROR("can't connect to a closed import\n");
 668                 RETURN(-EINVAL);
 669         } else if (imp->imp_state == LUSTRE_IMP_FULL) {
 670                 spin_unlock(&imp->imp_lock);
 671                 CERROR("already connected\n");
 672                 RETURN(0);
 673         } else if (imp->imp_state == LUSTRE_IMP_CONNECTING ||
 674                    imp->imp_connected) {
 675                 spin_unlock(&imp->imp_lock);
 676                 CERROR("already connecting\n");
 677                 RETURN(-EALREADY);
 678         }
 679
 680         IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_CONNECTING);
 681
 682         imp->imp_conn_cnt++;
 683         imp->imp_resend_replay = 0;
 684
 685         if (!lustre_handle_is_used(&imp->imp_remote_handle))
 686                 initial_connect = 1;
 687         else
 688                 committed_before_reconnect = imp->imp_peer_committed_transno;
 689
 690         set_transno = ptlrpc_first_transno(imp,
 691                                            &imp->imp_connect_data.ocd_transno);
 692         spin_unlock(&imp->imp_lock);
 693
 694         rc = import_select_connection(imp);
 695         if (rc)
 696                 GOTO(out, rc);
 697
 698         rc = sptlrpc_import_sec_adapt(imp, NULL, NULL);
 699         if (rc)
 700                 GOTO(out, rc);
 701
 702         /* Reset connect flags to the originally requested flags, in case
 703          * the server is updated on-the-fly we will get the new features. */
 704         imp->imp_connect_data.ocd_connect_flags = imp->imp_connect_flags_orig;
 705         imp->imp_connect_data.ocd_connect_flags2 = imp->imp_connect_flags2_orig;
 706         /* Reset ocd_version each time so the server knows the exact versions */
 707         imp->imp_connect_data.ocd_version = LUSTRE_VERSION_CODE;
 708         imp->imp_msghdr_flags &= ~MSGHDR_AT_SUPPORT;
 709         imp->imp_msghdr_flags &= ~MSGHDR_CKSUM_INCOMPAT18;
 710
 711         rc = obd_reconnect(NULL, imp->imp_obd->obd_self_export, obd,
 712                            &obd->obd_uuid, &imp->imp_connect_data, NULL);
 713         if (rc)
 714                 GOTO(out, rc);
 715
 716         request = ptlrpc_request_alloc(imp, &RQF_MDS_CONNECT);
 717         if (request == NULL)
 718                 GOTO(out, rc = -ENOMEM);
 719
 720         rc = ptlrpc_request_bufs_pack(request, LUSTRE_OBD_VERSION,
 721                                       imp->imp_connect_op, bufs, NULL);
 722         if (rc) {
 723                 ptlrpc_request_free(request);
 724                 GOTO(out, rc);
 725         }
 726
 727         /* Report the rpc service time to the server so that it knows how long
 728          * to wait for clients to join recovery */
 729         lustre_msg_set_service_time(request->rq_reqmsg,
 730                                     at_timeout2est(request->rq_timeout));
 731
 732         /* The amount of time we give the server to process the connect req.
 733          * import_select_connection will increase the net latency on
 734          * repeated reconnect attempts to cover slow networks.
 735          * We override/ignore the server rpc completion estimate here,
 736          * which may be large if this is a reconnect attempt */
 737         request->rq_timeout = INITIAL_CONNECT_TIMEOUT;
 738         lustre_msg_set_timeout(request->rq_reqmsg, request->rq_timeout);
 739
 740         request->rq_no_resend = request->rq_no_delay = 1;
 741         request->rq_send_state = LUSTRE_IMP_CONNECTING;
 742         /* Allow a slightly larger reply for future growth compatibility */
 743         req_capsule_set_size(&request->rq_pill, &RMF_CONNECT_DATA, RCL_SERVER,
 744                              sizeof(struct obd_connect_data)+16*sizeof(__u64));
 745         ptlrpc_request_set_replen(request);
 746         request->rq_interpret_reply = ptlrpc_connect_interpret;
 747
 748         CLASSERT(sizeof(*aa) <= sizeof(request->rq_async_args));
 749         aa = ptlrpc_req_async_args(request);
 750         memset(aa, 0, sizeof *aa);
 751
 752         aa->pcaa_peer_committed = committed_before_reconnect;
 753         aa->pcaa_initial_connect = initial_connect;
 754
 755         if (aa->pcaa_initial_connect) {
 756                 spin_lock(&imp->imp_lock);
 757                 imp->imp_replayable = 1;
 758                 spin_unlock(&imp->imp_lock);
 759                 lustre_msg_add_op_flags(request->rq_reqmsg,
 760                                         MSG_CONNECT_INITIAL);
 761         }
 762
 763         if (set_transno)
 764                 lustre_msg_add_op_flags(request->rq_reqmsg,
 765                                         MSG_CONNECT_TRANSNO);
 766
 767         DEBUG_REQ(D_RPCTRACE, request, "(re)connect request (timeout %ld)",
 768                   request->rq_timeout);
 769         ptlrpcd_add_req(request);
 770         rc = 0;
 771 out:
 772         if (rc != 0)
 773                 IMPORT_SET_STATE(imp, LUSTRE_IMP_DISCON);
 774
 775         RETURN(rc);
 776 }
 777 EXPORT_SYMBOL(ptlrpc_connect_import);
 778
 779 static void ptlrpc_maybe_ping_import_soon(struct obd_import *imp)
 780 {
 781         int force_verify;
 782
 783         spin_lock(&imp->imp_lock);
 784         force_verify = imp->imp_force_verify != 0;
 785         spin_unlock(&imp->imp_lock);
 786
 787         if (force_verify)
 788                 ptlrpc_pinger_wake_up();
 789 }
 790
 791 static int ptlrpc_busy_reconnect(int rc)
 792 {
 793         return (rc == -EBUSY) || (rc == -EAGAIN);
 794 }
 795
 796 static int ptlrpc_connect_set_flags(struct obd_import *imp,
 797                                      struct obd_connect_data *ocd,
 798                                      __u64 old_connect_flags,
 799                                      struct obd_export *exp, int init_connect)
 800 {
 801         static bool warned;
 802         struct client_obd *cli = &imp->imp_obd->u.cli;
 803
 804         if ((imp->imp_connect_flags_orig & OBD_CONNECT_IBITS) &&
 805             !(ocd->ocd_connect_flags & OBD_CONNECT_IBITS)) {
 806                 LCONSOLE_WARN("%s: MDS %s does not support ibits "
 807                               "lock, either very old or invalid: "
 808                               "requested %#llx, replied %#llx\n",
 809                               imp->imp_obd->obd_name,
 810                               imp->imp_connection->c_remote_uuid.uuid,
 811                               imp->imp_connect_flags_orig,
 812                               ocd->ocd_connect_flags);
 813                 return -EPROTO;
 814         }
 815
 816         spin_lock(&imp->imp_lock);
 817         list_del(&imp->imp_conn_current->oic_item);
 818         list_add(&imp->imp_conn_current->oic_item,
 819                  &imp->imp_conn_list);
 820         imp->imp_last_success_conn =
 821                 imp->imp_conn_current->oic_last_attempt;
 822
 823         spin_unlock(&imp->imp_lock);
 824
 825         if (!warned && (ocd->ocd_connect_flags & OBD_CONNECT_VERSION) &&
 826             (ocd->ocd_version > LUSTRE_VERSION_CODE +
 827                                 LUSTRE_VERSION_OFFSET_WARN ||
 828              ocd->ocd_version < LUSTRE_VERSION_CODE -
 829                                 LUSTRE_VERSION_OFFSET_WARN)) {
 830                 /* Sigh, some compilers do not like #ifdef in the middle
 831                    of macro arguments */
 832                 const char *older = "older than client. "
 833                                     "Consider upgrading server";
 834                 const char *newer = "newer than client. "
 835                                     "Consider upgrading client";
 836
 837                 LCONSOLE_WARN("Server %s version (%d.%d.%d.%d) "
 838                               "is much %s (%s)\n",
 839                               obd2cli_tgt(imp->imp_obd),
 840                               OBD_OCD_VERSION_MAJOR(ocd->ocd_version),
 841                               OBD_OCD_VERSION_MINOR(ocd->ocd_version),
 842                               OBD_OCD_VERSION_PATCH(ocd->ocd_version),
 843                               OBD_OCD_VERSION_FIX(ocd->ocd_version),
 844                               ocd->ocd_version > LUSTRE_VERSION_CODE ?
 845                               newer : older, LUSTRE_VERSION_STRING);
 846                 warned = true;
 847         }
 848
 849 #if LUSTRE_VERSION_CODE < OBD_OCD_VERSION(3, 0, 53, 0)
 850         /* Check if server has LU-1252 fix applied to not always swab
 851          * the IR MNE entries. Do this only once per connection.  This
 852          * fixup is version-limited, because we don't want to carry the
 853          * OBD_CONNECT_MNE_SWAB flag around forever, just so long as we
 854          * need interop with unpatched 2.2 servers.  For newer servers,
 855          * the client will do MNE swabbing only as needed.  LU-1644 */
 856         if (unlikely((ocd->ocd_connect_flags & OBD_CONNECT_VERSION) &&
 857                      !(ocd->ocd_connect_flags & OBD_CONNECT_MNE_SWAB) &&
 858                      OBD_OCD_VERSION_MAJOR(ocd->ocd_version) == 2 &&
 859                      OBD_OCD_VERSION_MINOR(ocd->ocd_version) == 2 &&
 860                      OBD_OCD_VERSION_PATCH(ocd->ocd_version) < 55 &&
 861                      strcmp(imp->imp_obd->obd_type->typ_name,
 862                             LUSTRE_MGC_NAME) == 0))
 863                 imp->imp_need_mne_swab = 1;
 864         else /* clear if server was upgraded since last connect */
 865                 imp->imp_need_mne_swab = 0;
 866 #endif
 867
 868         if (ocd->ocd_connect_flags & OBD_CONNECT_CKSUM) {
 869                 /* We sent to the server ocd_cksum_types with bits set
 870                  * for algorithms we understand. The server masked off
 871                  * the checksum types it doesn't support */
 872                 if ((ocd->ocd_cksum_types &
 873                      cksum_types_supported_client()) == 0) {
 874                         LCONSOLE_ERROR("The negotiation of the checksum "
 875                                        "alogrithm to use with server %s "
 876                                        "failed (%x/%x)\n",
 877                                        obd2cli_tgt(imp->imp_obd),
 878                                        ocd->ocd_cksum_types,
 879                                        cksum_types_supported_client());
 880                         return -EPROTO;
 881                 } else {
 882                         cli->cl_supp_cksum_types = ocd->ocd_cksum_types;
 883                 }
 884         } else {
 885                 /* The server does not support OBD_CONNECT_CKSUM.
 886                  * Enforce ADLER for backward compatibility*/
 887                 cli->cl_supp_cksum_types = OBD_CKSUM_ADLER;
 888         }
 889         cli->cl_cksum_type = cksum_type_select(cli->cl_supp_cksum_types);
 890
 891         if (ocd->ocd_connect_flags & OBD_CONNECT_BRW_SIZE)
 892                 cli->cl_max_pages_per_rpc =
 893                         min(ocd->ocd_brw_size >> PAGE_SHIFT,
 894                             cli->cl_max_pages_per_rpc);
 895         else if (imp->imp_connect_op == MDS_CONNECT ||
 896                  imp->imp_connect_op == MGS_CONNECT)
 897                 cli->cl_max_pages_per_rpc = 1;
 898
 899         LASSERT((cli->cl_max_pages_per_rpc <= PTLRPC_MAX_BRW_PAGES) &&
 900                 (cli->cl_max_pages_per_rpc > 0));
 901
 902         client_adjust_max_dirty(cli);
 903
 904         /* Update client max modify RPCs in flight with value returned
 905          * by the server */
 906         if (ocd->ocd_connect_flags & OBD_CONNECT_MULTIMODRPCS)
 907                 cli->cl_max_mod_rpcs_in_flight = min(
 908                                         cli->cl_max_mod_rpcs_in_flight,
 909                                         ocd->ocd_maxmodrpcs);
 910         else
 911                 cli->cl_max_mod_rpcs_in_flight = 1;
 912
 913         /* Reset ns_connect_flags only for initial connect. It might be
 914          * changed in while using FS and if we reset it in reconnect
 915          * this leads to losing user settings done before such as
 916          * disable lru_resize, etc. */
 917         if (old_connect_flags != exp_connect_flags(exp) || init_connect) {
 918                 CDEBUG(D_HA, "%s: Resetting ns_connect_flags to server "
 919                              "flags: %#llx\n", imp->imp_obd->obd_name,
 920                              ocd->ocd_connect_flags);
 921                 imp->imp_obd->obd_namespace->ns_connect_flags =
 922                         ocd->ocd_connect_flags;
 923                 imp->imp_obd->obd_namespace->ns_orig_connect_flags =
 924                         ocd->ocd_connect_flags;
 925         }
 926
 927         if (ocd->ocd_connect_flags & OBD_CONNECT_AT)
 928                 /* We need a per-message support flag, because
 929                  * a. we don't know if the incoming connect reply
 930                  *    supports AT or not (in reply_in_callback)
 931                  *    until we unpack it.
 932                  * b. failovered server means export and flags are gone
 933                  *    (in ptlrpc_send_reply).
 934                  *    Can only be set when we know AT is supported at
 935                  *    both ends */
 936                 imp->imp_msghdr_flags |= MSGHDR_AT_SUPPORT;
 937         else
 938                 imp->imp_msghdr_flags &= ~MSGHDR_AT_SUPPORT;
 939
 940         imp->imp_msghdr_flags |= MSGHDR_CKSUM_INCOMPAT18;
 941
 942         return 0;
 943 }
 944
 945 /**
 946  * Add all replay requests back to unreplied list before start replay,
 947  * so that we can make sure the known replied XID is always increased
 948  * only even if when replaying requests.
 949  */
 950 static void ptlrpc_prepare_replay(struct obd_import *imp)
 951 {
 952         struct ptlrpc_request *req;
 953
 954         if (imp->imp_state != LUSTRE_IMP_REPLAY ||
 955             imp->imp_resend_replay)
 956                 return;
 957
 958         /* If the server was restart during repaly, the requests may
 959          * have been added to the unreplied list in former replay. */
 960         spin_lock(&imp->imp_lock);
 961
 962         list_for_each_entry(req, &imp->imp_committed_list, rq_replay_list) {
 963                 if (list_empty(&req->rq_unreplied_list))
 964                         ptlrpc_add_unreplied(req);
 965         }
 966
 967         list_for_each_entry(req, &imp->imp_replay_list, rq_replay_list) {
 968                 if (list_empty(&req->rq_unreplied_list))
 969                         ptlrpc_add_unreplied(req);
 970         }
 971
 972         imp->imp_known_replied_xid = ptlrpc_known_replied_xid(imp);
 973         spin_unlock(&imp->imp_lock);
 974 }
 975
 976 /**
 977  * interpret_reply callback for connect RPCs.
 978  * Looks into returned status of connect operation and decides
 979  * what to do with the import - i.e enter recovery, promote it to
 980  * full state for normal operations of disconnect it due to an error.
 981  */
 982 static int ptlrpc_connect_interpret(const struct lu_env *env,
 983                                     struct ptlrpc_request *request,
 984                                     void *data, int rc)
 985 {
 986         struct ptlrpc_connect_async_args *aa = data;
 987         struct obd_import *imp = request->rq_import;
 988         struct lustre_handle old_hdl;
 989         __u64 old_connect_flags;
 990         int msg_flags;
 991         struct obd_connect_data *ocd;
 992         struct obd_export *exp;
 993         int ret;
 994         ENTRY;
 995
 996         spin_lock(&imp->imp_lock);
 997         if (imp->imp_state == LUSTRE_IMP_CLOSED) {
 998                 imp->imp_connect_tried = 1;
 999                 spin_unlock(&imp->imp_lock);
1000                 RETURN(0);
1001         }
1002
1003         if (rc) {
1004                 /* if this reconnect to busy export - not need select new target
1005                  * for connecting*/
1006                 imp->imp_force_reconnect = ptlrpc_busy_reconnect(rc);
1007                 spin_unlock(&imp->imp_lock);
1008                 ptlrpc_maybe_ping_import_soon(imp);
1009                 GOTO(out, rc);
1010         }
1011
1012         /* LU-7558: indicate that we are interpretting connect reply,
1013          * pltrpc_connect_import() will not try to reconnect until
1014          * interpret will finish. */
1015         imp->imp_connected = 1;
1016         spin_unlock(&imp->imp_lock);
1017
1018         LASSERT(imp->imp_conn_current);
1019
1020         msg_flags = lustre_msg_get_op_flags(request->rq_repmsg);
1021
1022         ret = req_capsule_get_size(&request->rq_pill, &RMF_CONNECT_DATA,
1023                                    RCL_SERVER);
1024         /* server replied obd_connect_data is always bigger */
1025         ocd = req_capsule_server_sized_get(&request->rq_pill,
1026                                            &RMF_CONNECT_DATA, ret);
1027
1028         if (ocd == NULL) {
1029                 CERROR("%s: no connect data from server\n",
1030                        imp->imp_obd->obd_name);
1031                 rc = -EPROTO;
1032                 GOTO(out, rc);
1033         }
1034
1035         spin_lock(&imp->imp_lock);
1036
1037         /* All imports are pingable */
1038         imp->imp_pingable = 1;
1039         imp->imp_force_reconnect = 0;
1040         imp->imp_force_verify = 0;
1041
1042         imp->imp_connect_data = *ocd;
1043
1044         CDEBUG(D_HA, "%s: connect to target with instance %u\n",
1045                imp->imp_obd->obd_name, ocd->ocd_instance);
1046         exp = class_conn2export(&imp->imp_dlm_handle);
1047
1048         spin_unlock(&imp->imp_lock);
1049
1050         if (!exp) {
1051                 /* This could happen if export is cleaned during the
1052                    connect attempt */
1053                 CERROR("%s: missing export after connect\n",
1054                        imp->imp_obd->obd_name);
1055                 GOTO(out, rc = -ENODEV);
1056         }
1057
1058         /* check that server granted subset of flags we asked for. */
1059         if ((ocd->ocd_connect_flags & imp->imp_connect_flags_orig) !=
1060             ocd->ocd_connect_flags) {
1061                 CERROR("%s: Server didn't grant requested subset of flags: "
1062                        "asked=%#llx granted=%#llx\n",
1063                        imp->imp_obd->obd_name, imp->imp_connect_flags_orig,
1064                        ocd->ocd_connect_flags);
1065                 GOTO(out, rc = -EPROTO);
1066         }
1067
1068         if ((ocd->ocd_connect_flags2 & imp->imp_connect_flags2_orig) !=
1069             ocd->ocd_connect_flags2) {
1070                 CERROR("%s: Server didn't grant requested subset of flags2: "
1071                        "asked=%#llx granted=%#llx\n",
1072                        imp->imp_obd->obd_name, imp->imp_connect_flags2_orig,
1073                        ocd->ocd_connect_flags2);
1074                 GOTO(out, rc = -EPROTO);
1075         }
1076
1077         if (!(imp->imp_connect_flags_orig & OBD_CONNECT_LIGHTWEIGHT) &&
1078             (imp->imp_connect_flags_orig & OBD_CONNECT_MDS_MDS) &&
1079             (imp->imp_connect_flags_orig & OBD_CONNECT_FID) &&
1080             (ocd->ocd_connect_flags & OBD_CONNECT_VERSION)) {
1081                 __u32 major = OBD_OCD_VERSION_MAJOR(ocd->ocd_version);
1082                 __u32 minor = OBD_OCD_VERSION_MINOR(ocd->ocd_version);
1083                 __u32 patch = OBD_OCD_VERSION_PATCH(ocd->ocd_version);
1084
1085                 /* We do not support the MDT-MDT interoperations with
1086                  * different version MDT because of protocol changes. */
1087                 if (unlikely(major != LUSTRE_MAJOR ||
1088                              minor != LUSTRE_MINOR ||
1089                              abs(patch - LUSTRE_PATCH) > 3)) {
1090                         LCONSOLE_WARN("%s: import %p (%u.%u.%u.%u) tried the "
1091                                       "connection to different version MDT "
1092                                       "(%d.%d.%d.%d) %s\n",
1093                                       imp->imp_obd->obd_name, imp, LUSTRE_MAJOR,
1094                                       LUSTRE_MINOR, LUSTRE_PATCH, LUSTRE_FIX,
1095                                       major, minor, patch,
1096                                       OBD_OCD_VERSION_FIX(ocd->ocd_version),
1097                                       imp->imp_connection->c_remote_uuid.uuid);
1098
1099                         GOTO(out, rc = -EPROTO);
1100                 }
1101         }
1102
1103         old_connect_flags = exp_connect_flags(exp);
1104         exp->exp_connect_data = *ocd;
1105         imp->imp_obd->obd_self_export->exp_connect_data = *ocd;
1106
1107         /* The net statistics after (re-)connect is not valid anymore,
1108          * because may reflect other routing, etc. */
1109         at_reinit(&imp->imp_at.iat_net_latency, 0, 0);
1110         ptlrpc_at_adj_net_latency(request,
1111                         lustre_msg_get_service_time(request->rq_repmsg));
1112
1113         /* Import flags should be updated before waking import at FULL state */
1114         rc = ptlrpc_connect_set_flags(imp, ocd, old_connect_flags, exp,
1115                                       aa->pcaa_initial_connect);
1116         class_export_put(exp);
1117         if (rc != 0)
1118                 GOTO(out, rc);
1119
1120         obd_import_event(imp->imp_obd, imp, IMP_EVENT_OCD);
1121
1122         if (aa->pcaa_initial_connect) {
1123                 spin_lock(&imp->imp_lock);
1124                 if (msg_flags & MSG_CONNECT_REPLAYABLE) {
1125                         imp->imp_replayable = 1;
1126                         spin_unlock(&imp->imp_lock);
1127                         CDEBUG(D_HA, "connected to replayable target: %s\n",
1128                                obd2cli_tgt(imp->imp_obd));
1129                 } else {
1130                         imp->imp_replayable = 0;
1131                         spin_unlock(&imp->imp_lock);
1132                 }
1133
1134                 /* if applies, adjust the imp->imp_msg_magic here
1135                  * according to reply flags */
1136
1137                 imp->imp_remote_handle =
1138                                 *lustre_msg_get_handle(request->rq_repmsg);
1139
1140                 /* Initial connects are allowed for clients with non-random
1141                  * uuids when servers are in recovery.  Simply signal the
1142                  * servers replay is complete and wait in REPLAY_WAIT. */
1143                 if (msg_flags & MSG_CONNECT_RECOVERING) {
1144                         CDEBUG(D_HA, "connect to %s during recovery\n",
1145                                obd2cli_tgt(imp->imp_obd));
1146                         IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY_LOCKS);
1147                 } else {
1148                         IMPORT_SET_STATE(imp, LUSTRE_IMP_FULL);
1149                         ptlrpc_activate_import(imp);
1150                 }
1151
1152                 GOTO(finish, rc = 0);
1153         }
1154
1155         /* Determine what recovery state to move the import to. */
1156         if (MSG_CONNECT_RECONNECT & msg_flags) {
1157                 memset(&old_hdl, 0, sizeof(old_hdl));
1158                 if (!memcmp(&old_hdl, lustre_msg_get_handle(request->rq_repmsg),
1159                             sizeof (old_hdl))) {
1160                         LCONSOLE_WARN("Reconnect to %s (at @%s) failed due "
1161                                       "bad handle %#llx\n",
1162                                       obd2cli_tgt(imp->imp_obd),
1163                                       imp->imp_connection->c_remote_uuid.uuid,
1164                                       imp->imp_dlm_handle.cookie);
1165                         GOTO(out, rc = -ENOTCONN);
1166                 }
1167
1168                 if (memcmp(&imp->imp_remote_handle,
1169                            lustre_msg_get_handle(request->rq_repmsg),
1170                            sizeof(imp->imp_remote_handle))) {
1171                         int level = msg_flags & MSG_CONNECT_RECOVERING ?
1172                                 D_HA : D_WARNING;
1173
1174                         /* Bug 16611/14775: if server handle have changed,
1175                          * that means some sort of disconnection happened.
1176                          * If the server is not in recovery, that also means it
1177                          * already erased all of our state because of previous
1178                          * eviction. If it is in recovery - we are safe to
1179                          * participate since we can reestablish all of our state
1180                          * with server again */
1181                         if ((MSG_CONNECT_RECOVERING & msg_flags)) {
1182                                 CDEBUG(level,"%s@%s changed server handle from "
1183                                        "%#llx to %#llx"
1184                                        " but is still in recovery\n",
1185                                        obd2cli_tgt(imp->imp_obd),
1186                                        imp->imp_connection->c_remote_uuid.uuid,
1187                                        imp->imp_remote_handle.cookie,
1188                                        lustre_msg_get_handle(
1189                                        request->rq_repmsg)->cookie);
1190                         } else {
1191                                 LCONSOLE_WARN("Evicted from %s (at %s) "
1192                                               "after server handle changed from "
1193                                               "%#llx to %#llx\n",
1194                                               obd2cli_tgt(imp->imp_obd),
1195                                               imp->imp_connection-> \
1196                                               c_remote_uuid.uuid,
1197                                               imp->imp_remote_handle.cookie,
1198                                               lustre_msg_get_handle(
1199                                               request->rq_repmsg)->cookie);
1200                         }
1201
1202
1203                         imp->imp_remote_handle =
1204                                      *lustre_msg_get_handle(request->rq_repmsg);
1205
1206                         if (!(MSG_CONNECT_RECOVERING & msg_flags)) {
1207                                 IMPORT_SET_STATE(imp, LUSTRE_IMP_EVICTED);
1208                                 GOTO(finish, rc = 0);
1209                         }
1210
1211                 } else {
1212                         CDEBUG(D_HA, "reconnected to %s@%s after partition\n",
1213                                obd2cli_tgt(imp->imp_obd),
1214                                imp->imp_connection->c_remote_uuid.uuid);
1215                 }
1216
1217                 if (imp->imp_invalid) {
1218                         CDEBUG(D_HA, "%s: reconnected but import is invalid; "
1219                                "marking evicted\n", imp->imp_obd->obd_name);
1220                         IMPORT_SET_STATE(imp, LUSTRE_IMP_EVICTED);
1221                 } else if (MSG_CONNECT_RECOVERING & msg_flags) {
1222                         CDEBUG(D_HA, "%s: reconnected to %s during replay\n",
1223                                imp->imp_obd->obd_name,
1224                                obd2cli_tgt(imp->imp_obd));
1225
1226                         spin_lock(&imp->imp_lock);
1227                         imp->imp_resend_replay = 1;
1228                         spin_unlock(&imp->imp_lock);
1229
1230                         IMPORT_SET_STATE(imp, imp->imp_replay_state);
1231                 } else {
1232                         IMPORT_SET_STATE(imp, LUSTRE_IMP_RECOVER);
1233                 }
1234         } else if ((MSG_CONNECT_RECOVERING & msg_flags) && !imp->imp_invalid) {
1235                 LASSERT(imp->imp_replayable);
1236                 imp->imp_remote_handle =
1237                                 *lustre_msg_get_handle(request->rq_repmsg);
1238                 imp->imp_last_replay_transno = 0;
1239                 imp->imp_replay_cursor = &imp->imp_committed_list;
1240                 IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY);
1241         } else {
1242                 DEBUG_REQ(D_HA, request, "%s: evicting (reconnect/recover flags"
1243                           " not set: %x)", imp->imp_obd->obd_name, msg_flags);
1244                 imp->imp_remote_handle =
1245                                 *lustre_msg_get_handle(request->rq_repmsg);
1246                 IMPORT_SET_STATE(imp, LUSTRE_IMP_EVICTED);
1247         }
1248
1249         /* Sanity checks for a reconnected import. */
1250         if (!(imp->imp_replayable) != !(msg_flags & MSG_CONNECT_REPLAYABLE)) {
1251                 CERROR("imp_replayable flag does not match server "
1252                        "after reconnect. We should LBUG right here.\n");
1253         }
1254
1255         if (lustre_msg_get_last_committed(request->rq_repmsg) > 0 &&
1256             lustre_msg_get_last_committed(request->rq_repmsg) <
1257             aa->pcaa_peer_committed) {
1258                 CERROR("%s went back in time (transno %lld"
1259                        " was previously committed, server now claims %lld"
1260                        ")!  See https://bugzilla.lustre.org/show_bug.cgi?"
1261                        "id=9646\n",
1262                        obd2cli_tgt(imp->imp_obd), aa->pcaa_peer_committed,
1263                        lustre_msg_get_last_committed(request->rq_repmsg));
1264         }
1265
1266 finish:
1267         ptlrpc_prepare_replay(imp);
1268         rc = ptlrpc_import_recovery_state_machine(imp);
1269         if (rc == -ENOTCONN) {
1270                 CDEBUG(D_HA, "evicted/aborted by %s@%s during recovery;"
1271                        "invalidating and reconnecting\n",
1272                        obd2cli_tgt(imp->imp_obd),
1273                        imp->imp_connection->c_remote_uuid.uuid);
1274                 ptlrpc_connect_import(imp);
1275                 spin_lock(&imp->imp_lock);
1276                 imp->imp_connected = 0;
1277                 imp->imp_connect_tried = 1;
1278                 spin_unlock(&imp->imp_lock);
1279                 RETURN(0);
1280         }
1281
1282 out:
1283         spin_lock(&imp->imp_lock);
1284         imp->imp_connected = 0;
1285         imp->imp_connect_tried = 1;
1286         spin_unlock(&imp->imp_lock);
1287
1288         if (rc != 0) {
1289                 IMPORT_SET_STATE(imp, LUSTRE_IMP_DISCON);
1290                 if (rc == -EACCES) {
1291                         /*
1292                          * Give up trying to reconnect
1293                          * EACCES means client has no permission for connection
1294                          */
1295                         imp->imp_obd->obd_no_recov = 1;
1296                         ptlrpc_deactivate_import(imp);
1297                 }
1298
1299                 if (rc == -EPROTO) {
1300                         struct obd_connect_data *ocd;
1301
1302                         /* reply message might not be ready */
1303                         if (request->rq_repmsg == NULL)
1304                                 RETURN(-EPROTO);
1305
1306                         ocd = req_capsule_server_get(&request->rq_pill,
1307                                                      &RMF_CONNECT_DATA);
1308                         /* Servers are not supposed to refuse connections from
1309                          * clients based on version, only connection feature
1310                          * flags.  We should never see this from llite, but it
1311                          * may be useful for debugging in the future. */
1312                         if (ocd &&
1313                             (ocd->ocd_connect_flags & OBD_CONNECT_VERSION) &&
1314                             (ocd->ocd_version != LUSTRE_VERSION_CODE)) {
1315                                 LCONSOLE_ERROR_MSG(0x16a, "Server %s version "
1316                                         "(%d.%d.%d.%d)"
1317                                         " refused connection from this client "
1318                                         "with an incompatible version (%s).  "
1319                                         "Client must be recompiled\n",
1320                                         obd2cli_tgt(imp->imp_obd),
1321                                         OBD_OCD_VERSION_MAJOR(ocd->ocd_version),
1322                                         OBD_OCD_VERSION_MINOR(ocd->ocd_version),
1323                                         OBD_OCD_VERSION_PATCH(ocd->ocd_version),
1324                                         OBD_OCD_VERSION_FIX(ocd->ocd_version),
1325                                         LUSTRE_VERSION_STRING);
1326                                 ptlrpc_deactivate_import(imp);
1327                                 IMPORT_SET_STATE(imp, LUSTRE_IMP_CLOSED);
1328                         }
1329                         RETURN(-EPROTO);
1330                 }
1331
1332                 ptlrpc_maybe_ping_import_soon(imp);
1333
1334                 CDEBUG(D_HA, "recovery of %s on %s failed (%d)\n",
1335                        obd2cli_tgt(imp->imp_obd),
1336                        (char *)imp->imp_connection->c_remote_uuid.uuid, rc);
1337         }
1338
1339         wake_up_all(&imp->imp_recovery_waitq);
1340         RETURN(rc);
1341 }
1342
1343 /**
1344  * interpret callback for "completed replay" RPCs.
1345  * \see signal_completed_replay
1346  */
1347 static int completed_replay_interpret(const struct lu_env *env,
1348                                       struct ptlrpc_request *req,
1349                                       void * data, int rc)
1350 {
1351         ENTRY;
1352         atomic_dec(&req->rq_import->imp_replay_inflight);
1353         if (req->rq_status == 0 &&
1354             !req->rq_import->imp_vbr_failed) {
1355                 ptlrpc_import_recovery_state_machine(req->rq_import);
1356         } else {
1357                 if (req->rq_import->imp_vbr_failed) {
1358                         CDEBUG(D_WARNING,
1359                                "%s: version recovery fails, reconnecting\n",
1360                                req->rq_import->imp_obd->obd_name);
1361                 } else {
1362                         CDEBUG(D_HA, "%s: LAST_REPLAY message error: %d, "
1363                                      "reconnecting\n",
1364                                req->rq_import->imp_obd->obd_name,
1365                                req->rq_status);
1366                 }
1367                 ptlrpc_connect_import(req->rq_import);
1368         }
1369
1370         RETURN(0);
1371 }
1372
1373 /**
1374  * Let server know that we have no requests to replay anymore.
1375  * Achieved by just sending a PING request
1376  */
1377 static int signal_completed_replay(struct obd_import *imp)
1378 {
1379         struct ptlrpc_request *req;
1380         ENTRY;
1381
1382         if (unlikely(OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_FINISH_REPLAY)))
1383                 RETURN(0);
1384
1385         LASSERT(atomic_read(&imp->imp_replay_inflight) == 0);
1386         atomic_inc(&imp->imp_replay_inflight);
1387
1388         req = ptlrpc_request_alloc_pack(imp, &RQF_OBD_PING, LUSTRE_OBD_VERSION,
1389                                         OBD_PING);
1390         if (req == NULL) {
1391                 atomic_dec(&imp->imp_replay_inflight);
1392                 RETURN(-ENOMEM);
1393         }
1394
1395         ptlrpc_request_set_replen(req);
1396         req->rq_send_state = LUSTRE_IMP_REPLAY_WAIT;
1397         lustre_msg_add_flags(req->rq_reqmsg,
1398                              MSG_LOCK_REPLAY_DONE | MSG_REQ_REPLAY_DONE);
1399         if (AT_OFF)
1400                 req->rq_timeout *= 3;
1401         req->rq_interpret_reply = completed_replay_interpret;
1402
1403         ptlrpcd_add_req(req);
1404         RETURN(0);
1405 }
1406
1407 /**
1408  * In kernel code all import invalidation happens in its own
1409  * separate thread, so that whatever application happened to encounter
1410  * a problem could still be killed or otherwise continue
1411  */
1412 static int ptlrpc_invalidate_import_thread(void *data)
1413 {
1414         struct obd_import *imp = data;
1415
1416         ENTRY;
1417
1418         unshare_fs_struct();
1419
1420         CDEBUG(D_HA, "thread invalidate import %s to %s@%s\n",
1421                imp->imp_obd->obd_name, obd2cli_tgt(imp->imp_obd),
1422                imp->imp_connection->c_remote_uuid.uuid);
1423
1424         ptlrpc_invalidate_import(imp);
1425
1426         if (obd_dump_on_eviction) {
1427                 CERROR("dump the log upon eviction\n");
1428                 libcfs_debug_dumplog();
1429         }
1430
1431         IMPORT_SET_STATE(imp, LUSTRE_IMP_RECOVER);
1432         ptlrpc_import_recovery_state_machine(imp);
1433
1434         class_import_put(imp);
1435         RETURN(0);
1436 }
1437
1438 /**
1439  * This is the state machine for client-side recovery on import.
1440  *
1441  * Typicaly we have two possibly paths. If we came to server and it is not
1442  * in recovery, we just enter IMP_EVICTED state, invalidate our import
1443  * state and reconnect from scratch.
1444  * If we came to server that is in recovery, we enter IMP_REPLAY import state.
1445  * We go through our list of requests to replay and send them to server one by
1446  * one.
1447  * After sending all request from the list we change import state to
1448  * IMP_REPLAY_LOCKS and re-request all the locks we believe we have from server
1449  * and also all the locks we don't yet have and wait for server to grant us.
1450  * After that we send a special "replay completed" request and change import
1451  * state to IMP_REPLAY_WAIT.
1452  * Upon receiving reply to that "replay completed" RPC we enter IMP_RECOVER
1453  * state and resend all requests from sending list.
1454  * After that we promote import to FULL state and send all delayed requests
1455  * and import is fully operational after that.
1456  *
1457  */
1458 int ptlrpc_import_recovery_state_machine(struct obd_import *imp)
1459 {
1460         int rc = 0;
1461         int inflight;
1462         char *target_start;
1463         int target_len;
1464
1465         ENTRY;
1466         if (imp->imp_state == LUSTRE_IMP_EVICTED) {
1467                 deuuidify(obd2cli_tgt(imp->imp_obd), NULL,
1468                           &target_start, &target_len);
1469                 /* Don't care about MGC eviction */
1470                 if (strcmp(imp->imp_obd->obd_type->typ_name,
1471                            LUSTRE_MGC_NAME) != 0) {
1472                         LCONSOLE_ERROR_MSG(0x167, "%s: This client was evicted "
1473                                            "by %.*s; in progress operations "
1474                                            "using this service will fail.\n",
1475                                            imp->imp_obd->obd_name, target_len,
1476                                            target_start);
1477                 }
1478                 CDEBUG(D_HA, "evicted from %s@%s; invalidating\n",
1479                        obd2cli_tgt(imp->imp_obd),
1480                        imp->imp_connection->c_remote_uuid.uuid);
1481                 /* reset vbr_failed flag upon eviction */
1482                 spin_lock(&imp->imp_lock);
1483                 imp->imp_vbr_failed = 0;
1484                 spin_unlock(&imp->imp_lock);
1485
1486                 {
1487                 struct task_struct *task;
1488                 /* bug 17802:  XXX client_disconnect_export vs connect request
1489                  * race. if client is evicted at this time then we start
1490                  * invalidate thread without reference to import and import can
1491                  * be freed at same time. */
1492                 class_import_get(imp);
1493                 task = kthread_run(ptlrpc_invalidate_import_thread, imp,
1494                                      "ll_imp_inval");
1495                 if (IS_ERR(task)) {
1496                         class_import_put(imp);
1497                         CERROR("error starting invalidate thread: %d\n", rc);
1498                         rc = PTR_ERR(task);
1499                 } else {
1500                         rc = 0;
1501                 }
1502                 RETURN(rc);
1503                 }
1504         }
1505
1506         if (imp->imp_state == LUSTRE_IMP_REPLAY) {
1507                 CDEBUG(D_HA, "replay requested by %s\n",
1508                        obd2cli_tgt(imp->imp_obd));
1509                 rc = ptlrpc_replay_next(imp, &inflight);
1510                 if (inflight == 0 &&
1511                     atomic_read(&imp->imp_replay_inflight) == 0) {
1512                         IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY_LOCKS);
1513                         rc = ldlm_replay_locks(imp);
1514                         if (rc)
1515                                 GOTO(out, rc);
1516                 }
1517                 rc = 0;
1518         }
1519
1520         if (imp->imp_state == LUSTRE_IMP_REPLAY_LOCKS) {
1521                 if (atomic_read(&imp->imp_replay_inflight) == 0) {
1522                         IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY_WAIT);
1523                         rc = signal_completed_replay(imp);
1524                         if (rc)
1525                                 GOTO(out, rc);
1526                 }
1527         }
1528
1529         if (imp->imp_state == LUSTRE_IMP_REPLAY_WAIT) {
1530                 if (atomic_read(&imp->imp_replay_inflight) == 0) {
1531                         IMPORT_SET_STATE(imp, LUSTRE_IMP_RECOVER);
1532                 }
1533         }
1534
1535         if (imp->imp_state == LUSTRE_IMP_RECOVER) {
1536                 struct ptlrpc_connection *conn = imp->imp_connection;
1537
1538                 rc = ptlrpc_resend(imp);
1539                 if (rc)
1540                         GOTO(out, rc);
1541                 IMPORT_SET_STATE(imp, LUSTRE_IMP_FULL);
1542                 ptlrpc_activate_import(imp);
1543
1544                 LCONSOLE_INFO("%s: Connection restored to %s (at %s)\n",
1545                               imp->imp_obd->obd_name,
1546                               obd_uuid2str(&conn->c_remote_uuid),
1547                               libcfs_nid2str(imp->imp_connection->c_peer.nid));
1548         }
1549
1550         if (imp->imp_state == LUSTRE_IMP_FULL) {
1551                 wake_up_all(&imp->imp_recovery_waitq);
1552                 ptlrpc_wake_delayed(imp);
1553         }
1554
1555 out:
1556         RETURN(rc);
1557 }
1558
1559 int ptlrpc_disconnect_import(struct obd_import *imp, int noclose)
1560 {
1561         struct ptlrpc_request *req;
1562         int rq_opc, rc = 0;
1563         ENTRY;
1564
1565         if (imp->imp_obd->obd_force)
1566                 GOTO(set_state, rc);
1567
1568         switch (imp->imp_connect_op) {
1569         case OST_CONNECT:
1570                 rq_opc = OST_DISCONNECT;
1571                 break;
1572         case MDS_CONNECT:
1573                 rq_opc = MDS_DISCONNECT;
1574                 break;
1575         case MGS_CONNECT:
1576                 rq_opc = MGS_DISCONNECT;
1577                 break;
1578         default:
1579                 rc = -EINVAL;
1580                 CERROR("%s: don't know how to disconnect from %s "
1581                        "(connect_op %d): rc = %d\n",
1582                        imp->imp_obd->obd_name, obd2cli_tgt(imp->imp_obd),
1583                        imp->imp_connect_op, rc);
1584                 RETURN(rc);
1585         }
1586
1587         if (ptlrpc_import_in_recovery(imp)) {
1588                 struct l_wait_info lwi;
1589                 long timeout_jiffies;
1590                 time64_t timeout;
1591
1592                 if (AT_OFF) {
1593                         if (imp->imp_server_timeout)
1594                                 timeout = obd_timeout >> 1;
1595                         else
1596                                 timeout = obd_timeout;
1597                 } else {
1598                         u32 req_portal;
1599                         int idx;
1600
1601                         req_portal = imp->imp_client->cli_request_portal;
1602                         idx = import_at_get_index(imp, req_portal);
1603                         timeout = at_get(&imp->imp_at.iat_service_estimate[idx]);
1604                 }
1605
1606                 timeout_jiffies = cfs_time_seconds(timeout);
1607                 lwi = LWI_TIMEOUT_INTR(max_t(long, timeout_jiffies, 1),
1608                                        back_to_sleep, LWI_ON_SIGNAL_NOOP, NULL);
1609                 rc = l_wait_event(imp->imp_recovery_waitq,
1610                                   !ptlrpc_import_in_recovery(imp), &lwi);
1611
1612         }
1613
1614         spin_lock(&imp->imp_lock);
1615         if (imp->imp_state != LUSTRE_IMP_FULL)
1616                 GOTO(out, rc);
1617         spin_unlock(&imp->imp_lock);
1618
1619         req = ptlrpc_request_alloc_pack(imp, &RQF_MDS_DISCONNECT,
1620                                         LUSTRE_OBD_VERSION, rq_opc);
1621         if (req) {
1622                 /* We are disconnecting, do not retry a failed DISCONNECT rpc if
1623                  * it fails.  We can get through the above with a down server
1624                  * if the client doesn't know the server is gone yet. */
1625                 req->rq_no_resend = 1;
1626
1627                 /* We want client umounts to happen quickly, no matter the
1628                    server state... */
1629                 req->rq_timeout = min_t(int, req->rq_timeout,
1630                                         INITIAL_CONNECT_TIMEOUT);
1631
1632                 IMPORT_SET_STATE(imp, LUSTRE_IMP_CONNECTING);
1633                 req->rq_send_state =  LUSTRE_IMP_CONNECTING;
1634                 ptlrpc_request_set_replen(req);
1635                 rc = ptlrpc_queue_wait(req);
1636                 ptlrpc_req_finished(req);
1637         }
1638
1639 set_state:
1640         spin_lock(&imp->imp_lock);
1641 out:
1642         if (noclose)
1643                 IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_DISCON);
1644         else
1645                 IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_CLOSED);
1646         memset(&imp->imp_remote_handle, 0, sizeof(imp->imp_remote_handle));
1647         spin_unlock(&imp->imp_lock);
1648
1649         if (rc == -ETIMEDOUT || rc == -ENOTCONN || rc == -ESHUTDOWN)
1650                 rc = 0;
1651         RETURN(rc);
1652 }
1653 EXPORT_SYMBOL(ptlrpc_disconnect_import);
1654
1655 void ptlrpc_cleanup_imp(struct obd_import *imp)
1656 {
1657         ENTRY;
1658
1659         spin_lock(&imp->imp_lock);
1660         IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_CLOSED);
1661         imp->imp_generation++;
1662         spin_unlock(&imp->imp_lock);
1663         ptlrpc_abort_inflight(imp);
1664
1665         EXIT;
1666 }
1667
1668 /* Adaptive Timeout utils */
1669 extern unsigned int at_min, at_max, at_history;
1670
1671 /* Update at_current with the specified value (bounded by at_min and at_max),
1672  * as well as the AT history "bins".
1673  *  - Bin into timeslices using AT_BINS bins.
1674  *  - This gives us a max of the last at_history seconds without the storage,
1675  *    but still smoothing out a return to normalcy from a slow response.
1676  *  - (E.g. remember the maximum latency in each minute of the last 4 minutes.)
1677  */
1678 int at_measured(struct adaptive_timeout *at, unsigned int val)
1679 {
1680         unsigned int old = at->at_current;
1681         time64_t now = ktime_get_real_seconds();
1682         long binlimit = max_t(long, at_history / AT_BINS, 1);
1683
1684         LASSERT(at);
1685         CDEBUG(D_OTHER, "add %u to %p time=%lu v=%u (%u %u %u %u)\n",
1686                val, at, (long)(now - at->at_binstart), at->at_current,
1687                at->at_hist[0], at->at_hist[1], at->at_hist[2], at->at_hist[3]);
1688
1689         if (val == 0)
1690                 /* 0's don't count, because we never want our timeout to
1691                    drop to 0, and because 0 could mean an error */
1692                 return 0;
1693
1694         spin_lock(&at->at_lock);
1695
1696         if (unlikely(at->at_binstart == 0)) {
1697                 /* Special case to remove default from history */
1698                 at->at_current = val;
1699                 at->at_worst_ever = val;
1700                 at->at_worst_time = now;
1701                 at->at_hist[0] = val;
1702                 at->at_binstart = now;
1703         } else if (now - at->at_binstart < binlimit ) {
1704                 /* in bin 0 */
1705                 at->at_hist[0] = max(val, at->at_hist[0]);
1706                 at->at_current = max(val, at->at_current);
1707         } else {
1708                 int i, shift;
1709                 unsigned int maxv = val;
1710
1711                 /* move bins over */
1712                 shift = (u32)(now - at->at_binstart) / binlimit;
1713                 LASSERT(shift > 0);
1714                 for(i = AT_BINS - 1; i >= 0; i--) {
1715                         if (i >= shift) {
1716                                 at->at_hist[i] = at->at_hist[i - shift];
1717                                 maxv = max(maxv, at->at_hist[i]);
1718                         } else {
1719                                 at->at_hist[i] = 0;
1720                         }
1721                 }
1722                 at->at_hist[0] = val;
1723                 at->at_current = maxv;
1724                 at->at_binstart += shift * binlimit;
1725         }
1726
1727         if (at->at_current > at->at_worst_ever) {
1728                 at->at_worst_ever = at->at_current;
1729                 at->at_worst_time = now;
1730         }
1731
1732         if (at->at_flags & AT_FLG_NOHIST)
1733                 /* Only keep last reported val; keeping the rest of the history
1734                    for proc only */
1735                 at->at_current = val;
1736
1737         if (at_max > 0)
1738                 at->at_current =  min(at->at_current, at_max);
1739         at->at_current =  max(at->at_current, at_min);
1740
1741         if (at->at_current != old)
1742                 CDEBUG(D_OTHER, "AT %p change: old=%u new=%u delta=%d "
1743                        "(val=%u) hist %u %u %u %u\n", at,
1744                        old, at->at_current, at->at_current - old, val,
1745                        at->at_hist[0], at->at_hist[1], at->at_hist[2],
1746                        at->at_hist[3]);
1747
1748         /* if we changed, report the old value */
1749         old = (at->at_current != old) ? old : 0;
1750
1751         spin_unlock(&at->at_lock);
1752         return old;
1753 }
1754
1755 /* Find the imp_at index for a given portal; assign if space available */
1756 int import_at_get_index(struct obd_import *imp, int portal)
1757 {
1758         struct imp_at *at = &imp->imp_at;
1759         int i;
1760
1761         for (i = 0; i < IMP_AT_MAX_PORTALS; i++) {
1762                 if (at->iat_portal[i] == portal)
1763                         return i;
1764                 if (at->iat_portal[i] == 0)
1765                         /* unused */
1766                         break;
1767         }
1768
1769         /* Not found in list, add it under a lock */
1770         spin_lock(&imp->imp_lock);
1771
1772         /* Check unused under lock */
1773         for (; i < IMP_AT_MAX_PORTALS; i++) {
1774                 if (at->iat_portal[i] == portal)
1775                         goto out;
1776                 if (at->iat_portal[i] == 0)
1777                         /* unused */
1778                         break;
1779         }
1780
1781         /* Not enough portals? */
1782         LASSERT(i < IMP_AT_MAX_PORTALS);
1783
1784         at->iat_portal[i] = portal;
1785 out:
1786         spin_unlock(&imp->imp_lock);
1787         return i;
1788 }