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.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2011, 2014, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * lustre/ptlrpc/import.c
  37  *
  38  * Author: Mike Shaver <shaver@clusterfs.com>
  39  */
  40
  41 #define DEBUG_SUBSYSTEM S_RPC
  42
  43 #include <linux/kthread.h>
  44 #include <obd_support.h>
  45 #include <lustre_ha.h>
  46 #include <lustre_net.h>
  47 #include <lustre_import.h>
  48 #include <lustre_export.h>
  49 #include <obd.h>
  50 #include <obd_cksum.h>
  51 #include <obd_class.h>
  52
  53 #include "ptlrpc_internal.h"
  54
  55 struct ptlrpc_connect_async_args {
  56          __u64 pcaa_peer_committed;
  57         int pcaa_initial_connect;
  58 };
  59
  60 /**
  61  * Updates import \a imp current state to provided \a state value
  62  * Helper function. Must be called under imp_lock.
  63  */
  64 static void __import_set_state(struct obd_import *imp,
  65                                enum lustre_imp_state state)
  66 {
  67         switch (state) {
  68         case LUSTRE_IMP_CLOSED:
  69         case LUSTRE_IMP_NEW:
  70         case LUSTRE_IMP_DISCON:
  71         case LUSTRE_IMP_CONNECTING:
  72                 break;
  73         case LUSTRE_IMP_REPLAY_WAIT:
  74                 imp->imp_replay_state = LUSTRE_IMP_REPLAY_LOCKS;
  75                 break;
  76         default:
  77                 imp->imp_replay_state = LUSTRE_IMP_REPLAY;
  78         }
  79         imp->imp_state = state;
  80         imp->imp_state_hist[imp->imp_state_hist_idx].ish_state = state;
  81         imp->imp_state_hist[imp->imp_state_hist_idx].ish_time =
  82                 cfs_time_current_sec();
  83         imp->imp_state_hist_idx = (imp->imp_state_hist_idx + 1) %
  84                 IMP_STATE_HIST_LEN;
  85 }
  86
  87 /* A CLOSED import should remain so. */
  88 #define IMPORT_SET_STATE_NOLOCK(imp, state)                                    \
  89 do {                                                                           \
  90         if (imp->imp_state != LUSTRE_IMP_CLOSED) {                             \
  91                CDEBUG(D_HA, "%p %s: changing import state from %s to %s\n",    \
  92                       imp, obd2cli_tgt(imp->imp_obd),                          \
  93                       ptlrpc_import_state_name(imp->imp_state),                \
  94                       ptlrpc_import_state_name(state));                        \
  95                __import_set_state(imp, state);                                 \
  96         }                                                                      \
  97 } while(0)
  98
  99 #define IMPORT_SET_STATE(imp, state)                                    \
 100 do {                                                                    \
 101         spin_lock(&imp->imp_lock);                                      \
 102         IMPORT_SET_STATE_NOLOCK(imp, state);                            \
 103         spin_unlock(&imp->imp_lock);                                    \
 104 } while(0)
 105
 106
 107 static int ptlrpc_connect_interpret(const struct lu_env *env,
 108                                     struct ptlrpc_request *request,
 109                                     void * data, int rc);
 110 int ptlrpc_import_recovery_state_machine(struct obd_import *imp);
 111
 112 /* Only this function is allowed to change the import state when it is
 113  * CLOSED. I would rather refcount the import and free it after
 114  * disconnection like we do with exports. To do that, the client_obd
 115  * will need to save the peer info somewhere other than in the import,
 116  * though. */
 117 int ptlrpc_init_import(struct obd_import *imp)
 118 {
 119         spin_lock(&imp->imp_lock);
 120
 121         imp->imp_generation++;
 122         imp->imp_state =  LUSTRE_IMP_NEW;
 123
 124         spin_unlock(&imp->imp_lock);
 125
 126         return 0;
 127 }
 128 EXPORT_SYMBOL(ptlrpc_init_import);
 129
 130 #define UUID_STR "_UUID"
 131 void deuuidify(char *uuid, const char *prefix, char **uuid_start, int *uuid_len)
 132 {
 133         *uuid_start = !prefix || strncmp(uuid, prefix, strlen(prefix))
 134                 ? uuid : uuid + strlen(prefix);
 135
 136         *uuid_len = strlen(*uuid_start);
 137
 138         if (*uuid_len < strlen(UUID_STR))
 139                 return;
 140
 141         if (!strncmp(*uuid_start + *uuid_len - strlen(UUID_STR),
 142                     UUID_STR, strlen(UUID_STR)))
 143                 *uuid_len -= strlen(UUID_STR);
 144 }
 145
 146 /**
 147  * Returns true if import was FULL, false if import was already not
 148  * connected.
 149  * @imp - import to be disconnected
 150  * @conn_cnt - connection count (epoch) of the request that timed out
 151  *             and caused the disconnection.  In some cases, multiple
 152  *             inflight requests can fail to a single target (e.g. OST
 153  *             bulk requests) and if one has already caused a reconnection
 154  *             (increasing the import->conn_cnt) the older failure should
 155  *             not also cause a reconnection.  If zero it forces a reconnect.
 156  */
 157 int ptlrpc_set_import_discon(struct obd_import *imp, __u32 conn_cnt)
 158 {
 159         int rc = 0;
 160
 161         spin_lock(&imp->imp_lock);
 162
 163         if (imp->imp_state == LUSTRE_IMP_FULL &&
 164             (conn_cnt == 0 || conn_cnt == imp->imp_conn_cnt)) {
 165                 char *target_start;
 166                 int   target_len;
 167
 168                 deuuidify(obd2cli_tgt(imp->imp_obd), NULL,
 169                           &target_start, &target_len);
 170
 171                 if (imp->imp_replayable) {
 172                         LCONSOLE_WARN("%s: Connection to %.*s (at %s) was "
 173                                "lost; in progress operations using this "
 174                                "service will wait for recovery to complete\n",
 175                                imp->imp_obd->obd_name, target_len, target_start,
 176                                libcfs_nid2str(imp->imp_connection->c_peer.nid));
 177                 } else {
 178                         LCONSOLE_ERROR_MSG(0x166, "%s: Connection to "
 179                                "%.*s (at %s) was lost; in progress "
 180                                "operations using this service will fail\n",
 181                                imp->imp_obd->obd_name,
 182                                target_len, target_start,
 183                                libcfs_nid2str(imp->imp_connection->c_peer.nid));
 184                 }
 185                 IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_DISCON);
 186                 spin_unlock(&imp->imp_lock);
 187
 188                 if (obd_dump_on_timeout)
 189                         libcfs_debug_dumplog();
 190
 191                 obd_import_event(imp->imp_obd, imp, IMP_EVENT_DISCON);
 192                 rc = 1;
 193         } else {
 194                 spin_unlock(&imp->imp_lock);
 195                 CDEBUG(D_HA, "%s: import %p already %s (conn %u, was %u): %s\n",
 196                        imp->imp_client->cli_name, imp,
 197                        (imp->imp_state == LUSTRE_IMP_FULL &&
 198                         imp->imp_conn_cnt > conn_cnt) ?
 199                        "reconnected" : "not connected", imp->imp_conn_cnt,
 200                        conn_cnt, ptlrpc_import_state_name(imp->imp_state));
 201         }
 202
 203         return rc;
 204 }
 205
 206 /* Must be called with imp_lock held! */
 207 static void ptlrpc_deactivate_and_unlock_import(struct obd_import *imp)
 208 {
 209         ENTRY;
 210         assert_spin_locked(&imp->imp_lock);
 211
 212         CDEBUG(D_HA, "setting import %s INVALID\n", obd2cli_tgt(imp->imp_obd));
 213         imp->imp_invalid = 1;
 214         imp->imp_generation++;
 215         spin_unlock(&imp->imp_lock);
 216
 217         ptlrpc_abort_inflight(imp);
 218         obd_import_event(imp->imp_obd, imp, IMP_EVENT_INACTIVE);
 219
 220         EXIT;
 221 }
 222
 223 /*
 224  * This acts as a barrier; all existing requests are rejected, and
 225  * no new requests will be accepted until the import is valid again.
 226  */
 227 void ptlrpc_deactivate_import(struct obd_import *imp)
 228 {
 229         spin_lock(&imp->imp_lock);
 230         ptlrpc_deactivate_and_unlock_import(imp);
 231 }
 232 EXPORT_SYMBOL(ptlrpc_deactivate_import);
 233
 234 static unsigned int
 235 ptlrpc_inflight_deadline(struct ptlrpc_request *req, time_t now)
 236 {
 237         long dl;
 238
 239         if (!(((req->rq_phase == RQ_PHASE_RPC) && !req->rq_waiting) ||
 240               (req->rq_phase == RQ_PHASE_BULK) ||
 241               (req->rq_phase == RQ_PHASE_NEW)))
 242                 return 0;
 243
 244         if (req->rq_timedout)
 245                 return 0;
 246
 247         if (req->rq_phase == RQ_PHASE_NEW)
 248                 dl = req->rq_sent;
 249         else
 250                 dl = req->rq_deadline;
 251
 252         if (dl <= now)
 253                 return 0;
 254
 255         return dl - now;
 256 }
 257
 258 static unsigned int ptlrpc_inflight_timeout(struct obd_import *imp)
 259 {
 260         time_t now = cfs_time_current_sec();
 261         struct list_head *tmp, *n;
 262         struct ptlrpc_request *req;
 263         unsigned int timeout = 0;
 264
 265         spin_lock(&imp->imp_lock);
 266         list_for_each_safe(tmp, n, &imp->imp_sending_list) {
 267                 req = list_entry(tmp, struct ptlrpc_request, rq_list);
 268                 timeout = max(ptlrpc_inflight_deadline(req, now), timeout);
 269         }
 270         spin_unlock(&imp->imp_lock);
 271         return timeout;
 272 }
 273
 274 /**
 275  * This function will invalidate the import, if necessary, then block
 276  * for all the RPC completions, and finally notify the obd to
 277  * invalidate its state (ie cancel locks, clear pending requests,
 278  * etc).
 279  */
 280 void ptlrpc_invalidate_import(struct obd_import *imp)
 281 {
 282         struct list_head *tmp, *n;
 283         struct ptlrpc_request *req;
 284         struct l_wait_info lwi;
 285         unsigned int timeout;
 286         int rc;
 287
 288         atomic_inc(&imp->imp_inval_count);
 289
 290         if (!imp->imp_invalid || imp->imp_obd->obd_no_recov)
 291                 ptlrpc_deactivate_import(imp);
 292
 293         CFS_FAIL_TIMEOUT(OBD_FAIL_MGS_CONNECT_NET, 3 * cfs_fail_val / 2);
 294         LASSERT(imp->imp_invalid);
 295
 296         /* Wait forever until inflight == 0. We really can't do it another
 297          * way because in some cases we need to wait for very long reply
 298          * unlink. We can't do anything before that because there is really
 299          * no guarantee that some rdma transfer is not in progress right now. */
 300         do {
 301                 /* Calculate max timeout for waiting on rpcs to error
 302                  * out. Use obd_timeout if calculated value is smaller
 303                  * than it. */
 304                 if (!OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_LONG_REPL_UNLINK)) {
 305                         timeout = ptlrpc_inflight_timeout(imp);
 306                         timeout += timeout / 3;
 307
 308                         if (timeout == 0)
 309                                 timeout = obd_timeout;
 310                 } else {
 311                         /* decrease the interval to increase race condition */
 312                         timeout = 1;
 313                 }
 314
 315                 CDEBUG(D_RPCTRACE,"Sleeping %d sec for inflight to error out\n",
 316                        timeout);
 317
 318                 /* Wait for all requests to error out and call completion
 319                  * callbacks. Cap it at obd_timeout -- these should all
 320                  * have been locally cancelled by ptlrpc_abort_inflight. */
 321                 lwi = LWI_TIMEOUT_INTERVAL(
 322                         cfs_timeout_cap(cfs_time_seconds(timeout)),
 323                         (timeout > 1)?cfs_time_seconds(1):cfs_time_seconds(1)/2,
 324                         NULL, NULL);
 325                 rc = l_wait_event(imp->imp_recovery_waitq,
 326                                   (atomic_read(&imp->imp_inflight) == 0),
 327                                   &lwi);
 328                 if (rc) {
 329                         const char *cli_tgt = obd2cli_tgt(imp->imp_obd);
 330
 331                         CERROR("%s: rc = %d waiting for callback (%d != 0)\n",
 332                                cli_tgt, rc, atomic_read(&imp->imp_inflight));
 333
 334                         spin_lock(&imp->imp_lock);
 335                         if (atomic_read(&imp->imp_inflight) == 0) {
 336                                 int count = atomic_read(&imp->imp_unregistering);
 337
 338                                 /* We know that "unregistering" rpcs only can
 339                                  * survive in sending or delaying lists (they
 340                                  * maybe waiting for long reply unlink in
 341                                  * sluggish nets). Let's check this. If there
 342                                  * is no inflight and unregistering != 0, this
 343                                  * is bug. */
 344                                 LASSERTF(count == 0, "Some RPCs are still "
 345                                          "unregistering: %d\n", count);
 346
 347                                 /* Let's save one loop as soon as inflight have
 348                                  * dropped to zero. No new inflights possible at
 349                                  * this point. */
 350                                 rc = 0;
 351                         } else {
 352                                 list_for_each_safe(tmp, n,
 353                                                    &imp->imp_sending_list) {
 354                                         req = list_entry(tmp,
 355                                                          struct ptlrpc_request,
 356                                                          rq_list);
 357                                         DEBUG_REQ(D_ERROR, req,
 358                                                   "still on sending list");
 359                                 }
 360                                 list_for_each_safe(tmp, n,
 361                                                    &imp->imp_delayed_list) {
 362                                         req = list_entry(tmp,
 363                                                          struct ptlrpc_request,
 364                                                          rq_list);
 365                                         DEBUG_REQ(D_ERROR, req,
 366                                                   "still on delayed list");
 367                                 }
 368
 369                                 CERROR("%s: RPCs in \"%s\" phase found (%d). "
 370                                        "Network is sluggish? Waiting them "
 371                                        "to error out.\n", cli_tgt,
 372                                        ptlrpc_phase2str(RQ_PHASE_UNREGISTERING),
 373                                        atomic_read(&imp->imp_unregistering));
 374                         }
 375                         spin_unlock(&imp->imp_lock);
 376                 }
 377         } while (rc != 0);
 378
 379         /*
 380          * Let's additionally check that no new rpcs added to import in
 381          * "invalidate" state.
 382          */
 383         LASSERT(atomic_read(&imp->imp_inflight) == 0);
 384         obd_import_event(imp->imp_obd, imp, IMP_EVENT_INVALIDATE);
 385         sptlrpc_import_flush_all_ctx(imp);
 386
 387         atomic_dec(&imp->imp_inval_count);
 388         wake_up_all(&imp->imp_recovery_waitq);
 389 }
 390 EXPORT_SYMBOL(ptlrpc_invalidate_import);
 391
 392 /* unset imp_invalid */
 393 void ptlrpc_activate_import(struct obd_import *imp)
 394 {
 395         struct obd_device *obd = imp->imp_obd;
 396
 397         spin_lock(&imp->imp_lock);
 398         if (imp->imp_deactive != 0) {
 399                 spin_unlock(&imp->imp_lock);
 400                 return;
 401         }
 402
 403         imp->imp_invalid = 0;
 404         spin_unlock(&imp->imp_lock);
 405         obd_import_event(obd, imp, IMP_EVENT_ACTIVE);
 406 }
 407 EXPORT_SYMBOL(ptlrpc_activate_import);
 408
 409 void ptlrpc_pinger_force(struct obd_import *imp)
 410 {
 411         CDEBUG(D_HA, "%s: waking up pinger s:%s\n", obd2cli_tgt(imp->imp_obd),
 412                ptlrpc_import_state_name(imp->imp_state));
 413
 414         spin_lock(&imp->imp_lock);
 415         imp->imp_force_verify = 1;
 416         spin_unlock(&imp->imp_lock);
 417
 418         if (imp->imp_state != LUSTRE_IMP_CONNECTING)
 419                 ptlrpc_pinger_wake_up();
 420 }
 421 EXPORT_SYMBOL(ptlrpc_pinger_force);
 422
 423 void ptlrpc_fail_import(struct obd_import *imp, __u32 conn_cnt)
 424 {
 425         ENTRY;
 426
 427         LASSERT(!imp->imp_dlm_fake);
 428
 429         if (ptlrpc_set_import_discon(imp, conn_cnt)) {
 430                 if (!imp->imp_replayable) {
 431                         CDEBUG(D_HA, "import %s@%s for %s not replayable, "
 432                                "auto-deactivating\n",
 433                                obd2cli_tgt(imp->imp_obd),
 434                                imp->imp_connection->c_remote_uuid.uuid,
 435                                imp->imp_obd->obd_name);
 436                         ptlrpc_deactivate_import(imp);
 437                 }
 438
 439                 ptlrpc_pinger_force(imp);
 440         }
 441         EXIT;
 442 }
 443
 444 int ptlrpc_reconnect_import(struct obd_import *imp)
 445 {
 446 #ifdef ENABLE_PINGER
 447         struct l_wait_info lwi;
 448         int secs = cfs_time_seconds(obd_timeout);
 449         int rc;
 450
 451         ptlrpc_pinger_force(imp);
 452
 453         CDEBUG(D_HA, "%s: recovery started, waiting %u seconds\n",
 454                obd2cli_tgt(imp->imp_obd), secs);
 455
 456         lwi = LWI_TIMEOUT(secs, NULL, NULL);
 457         rc = l_wait_event(imp->imp_recovery_waitq,
 458                           !ptlrpc_import_in_recovery(imp), &lwi);
 459         CDEBUG(D_HA, "%s: recovery finished s:%s\n", obd2cli_tgt(imp->imp_obd),
 460                ptlrpc_import_state_name(imp->imp_state));
 461         return rc;
 462 #else
 463         ptlrpc_set_import_discon(imp, 0);
 464         /* Force a new connect attempt */
 465         ptlrpc_invalidate_import(imp);
 466         /* Do a fresh connect next time by zeroing the handle */
 467         ptlrpc_disconnect_import(imp, 1);
 468         /* Wait for all invalidate calls to finish */
 469         if (atomic_read(&imp->imp_inval_count) > 0) {
 470                 struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
 471                 int rc;
 472
 473                 rc = l_wait_event(imp->imp_recovery_waitq,
 474                                   (atomic_read(&imp->imp_inval_count) == 0),
 475                                   &lwi);
 476                 if (rc)
 477                         CERROR("Interrupted, inval=%d\n",
 478                                atomic_read(&imp->imp_inval_count));
 479         }
 480
 481         /* Allow reconnect attempts */
 482         imp->imp_obd->obd_no_recov = 0;
 483         /* Remove 'invalid' flag */
 484         ptlrpc_activate_import(imp);
 485         /* Attempt a new connect */
 486         ptlrpc_recover_import(imp, NULL, 0);
 487         return 0;
 488 #endif
 489 }
 490 EXPORT_SYMBOL(ptlrpc_reconnect_import);
 491
 492 /**
 493  * Connection on import \a imp is changed to another one (if more than one is
 494  * present). We typically chose connection that we have not tried to connect to
 495  * the longest
 496  */
 497 static int import_select_connection(struct obd_import *imp)
 498 {
 499         struct obd_import_conn *imp_conn = NULL, *conn;
 500         struct obd_export *dlmexp;
 501         char *target_start;
 502         int target_len, tried_all = 1;
 503         ENTRY;
 504
 505         spin_lock(&imp->imp_lock);
 506
 507         if (list_empty(&imp->imp_conn_list)) {
 508                 CERROR("%s: no connections available\n",
 509                        imp->imp_obd->obd_name);
 510                 spin_unlock(&imp->imp_lock);
 511                 RETURN(-EINVAL);
 512         }
 513
 514         list_for_each_entry(conn, &imp->imp_conn_list, oic_item) {
 515                 CDEBUG(D_HA, "%s: connect to NID %s last attempt "LPU64"\n",
 516                        imp->imp_obd->obd_name,
 517                        libcfs_nid2str(conn->oic_conn->c_peer.nid),
 518                        conn->oic_last_attempt);
 519
 520                 /* If we have not tried this connection since
 521                    the last successful attempt, go with this one */
 522                 if ((conn->oic_last_attempt == 0) ||
 523                     cfs_time_beforeq_64(conn->oic_last_attempt,
 524                                        imp->imp_last_success_conn)) {
 525                         imp_conn = conn;
 526                         tried_all = 0;
 527                         break;
 528                 }
 529
 530                 /* If all of the connections have already been tried
 531                    since the last successful connection; just choose the
 532                    least recently used */
 533                 if (!imp_conn)
 534                         imp_conn = conn;
 535                 else if (cfs_time_before_64(conn->oic_last_attempt,
 536                                             imp_conn->oic_last_attempt))
 537                         imp_conn = conn;
 538         }
 539
 540         /* if not found, simply choose the current one */
 541         if (!imp_conn || imp->imp_force_reconnect) {
 542                 LASSERT(imp->imp_conn_current);
 543                 imp_conn = imp->imp_conn_current;
 544                 tried_all = 0;
 545         }
 546         LASSERT(imp_conn->oic_conn);
 547
 548         /* If we've tried everything, and we're back to the beginning of the
 549            list, increase our timeout and try again. It will be reset when
 550            we do finally connect. (FIXME: really we should wait for all network
 551            state associated with the last connection attempt to drain before
 552            trying to reconnect on it.) */
 553         if (tried_all && (imp->imp_conn_list.next == &imp_conn->oic_item)) {
 554                 struct adaptive_timeout *at = &imp->imp_at.iat_net_latency;
 555                 if (at_get(at) < CONNECTION_SWITCH_MAX) {
 556                         at_measured(at, at_get(at) + CONNECTION_SWITCH_INC);
 557                         if (at_get(at) > CONNECTION_SWITCH_MAX)
 558                                 at_reset(at, CONNECTION_SWITCH_MAX);
 559                 }
 560                 LASSERT(imp_conn->oic_last_attempt);
 561                 CDEBUG(D_HA, "%s: tried all connections, increasing latency "
 562                         "to %ds\n", imp->imp_obd->obd_name, at_get(at));
 563         }
 564
 565         imp_conn->oic_last_attempt = cfs_time_current_64();
 566
 567         /* switch connection, don't mind if it's same as the current one */
 568         if (imp->imp_connection)
 569                 ptlrpc_connection_put(imp->imp_connection);
 570         imp->imp_connection = ptlrpc_connection_addref(imp_conn->oic_conn);
 571
 572         dlmexp =  class_conn2export(&imp->imp_dlm_handle);
 573         LASSERT(dlmexp != NULL);
 574         if (dlmexp->exp_connection)
 575                 ptlrpc_connection_put(dlmexp->exp_connection);
 576         dlmexp->exp_connection = ptlrpc_connection_addref(imp_conn->oic_conn);
 577         class_export_put(dlmexp);
 578
 579         if (imp->imp_conn_current != imp_conn) {
 580                 if (imp->imp_conn_current) {
 581                         deuuidify(obd2cli_tgt(imp->imp_obd), NULL,
 582                                   &target_start, &target_len);
 583
 584                         CDEBUG(D_HA, "%s: Connection changing to"
 585                                " %.*s (at %s)\n",
 586                                imp->imp_obd->obd_name,
 587                                target_len, target_start,
 588                                libcfs_nid2str(imp_conn->oic_conn->c_peer.nid));
 589                 }
 590
 591                 imp->imp_conn_current = imp_conn;
 592         }
 593
 594         CDEBUG(D_HA, "%s: import %p using connection %s/%s\n",
 595                imp->imp_obd->obd_name, imp, imp_conn->oic_uuid.uuid,
 596                libcfs_nid2str(imp_conn->oic_conn->c_peer.nid));
 597
 598         spin_unlock(&imp->imp_lock);
 599
 600         RETURN(0);
 601 }
 602
 603 /*
 604  * must be called under imp_lock
 605  */
 606 static int ptlrpc_first_transno(struct obd_import *imp, __u64 *transno)
 607 {
 608         struct ptlrpc_request   *req;
 609         struct list_head        *tmp;
 610
 611         /* The requests in committed_list always have smaller transnos than
 612          * the requests in replay_list */
 613         if (!list_empty(&imp->imp_committed_list)) {
 614                 tmp = imp->imp_committed_list.next;
 615                 req = list_entry(tmp, struct ptlrpc_request, rq_replay_list);
 616                 *transno = req->rq_transno;
 617                 if (req->rq_transno == 0) {
 618                         DEBUG_REQ(D_ERROR, req, "zero transno in committed_list");
 619                         LBUG();
 620                 }
 621                 return 1;
 622         }
 623         if (!list_empty(&imp->imp_replay_list)) {
 624                 tmp = imp->imp_replay_list.next;
 625                 req = list_entry(tmp, struct ptlrpc_request, rq_replay_list);
 626                 *transno = req->rq_transno;
 627                 if (req->rq_transno == 0) {
 628                         DEBUG_REQ(D_ERROR, req, "zero transno in replay_list");
 629                         LBUG();
 630                 }
 631                 return 1;
 632         }
 633         return 0;
 634 }
 635
 636 /**
 637  * Attempt to (re)connect import \a imp. This includes all preparations,
 638  * initializing CONNECT RPC request and passing it to ptlrpcd for
 639  * actual sending.
 640  * Returns 0 on success or error code.
 641  */
 642 int ptlrpc_connect_import(struct obd_import *imp)
 643 {
 644         struct obd_device *obd = imp->imp_obd;
 645         int initial_connect = 0;
 646         int set_transno = 0;
 647         __u64 committed_before_reconnect = 0;
 648         struct ptlrpc_request *request;
 649         char *bufs[] = { NULL,
 650                          obd2cli_tgt(imp->imp_obd),
 651                          obd->obd_uuid.uuid,
 652                          (char *)&imp->imp_dlm_handle,
 653                          (char *)&imp->imp_connect_data };
 654         struct ptlrpc_connect_async_args *aa;
 655         int rc;
 656         ENTRY;
 657
 658         spin_lock(&imp->imp_lock);
 659         if (imp->imp_state == LUSTRE_IMP_CLOSED) {
 660                 spin_unlock(&imp->imp_lock);
 661                 CERROR("can't connect to a closed import\n");
 662                 RETURN(-EINVAL);
 663         } else if (imp->imp_state == LUSTRE_IMP_FULL) {
 664                 spin_unlock(&imp->imp_lock);
 665                 CERROR("already connected\n");
 666                 RETURN(0);
 667         } else if (imp->imp_state == LUSTRE_IMP_CONNECTING) {
 668                 spin_unlock(&imp->imp_lock);
 669                 CERROR("already connecting\n");
 670                 RETURN(-EALREADY);
 671         }
 672
 673         IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_CONNECTING);
 674
 675         imp->imp_conn_cnt++;
 676         imp->imp_resend_replay = 0;
 677
 678         if (!lustre_handle_is_used(&imp->imp_remote_handle))
 679                 initial_connect = 1;
 680         else
 681                 committed_before_reconnect = imp->imp_peer_committed_transno;
 682
 683         set_transno = ptlrpc_first_transno(imp,
 684                                            &imp->imp_connect_data.ocd_transno);
 685         spin_unlock(&imp->imp_lock);
 686
 687         rc = import_select_connection(imp);
 688         if (rc)
 689                 GOTO(out, rc);
 690
 691         rc = sptlrpc_import_sec_adapt(imp, NULL, NULL);
 692         if (rc)
 693                 GOTO(out, rc);
 694
 695         /* Reset connect flags to the originally requested flags, in case
 696          * the server is updated on-the-fly we will get the new features. */
 697         imp->imp_connect_data.ocd_connect_flags = imp->imp_connect_flags_orig;
 698         /* Reset ocd_version each time so the server knows the exact versions */
 699         imp->imp_connect_data.ocd_version = LUSTRE_VERSION_CODE;
 700         imp->imp_msghdr_flags &= ~MSGHDR_AT_SUPPORT;
 701         imp->imp_msghdr_flags &= ~MSGHDR_CKSUM_INCOMPAT18;
 702
 703         rc = obd_reconnect(NULL, imp->imp_obd->obd_self_export, obd,
 704                            &obd->obd_uuid, &imp->imp_connect_data, NULL);
 705         if (rc)
 706                 GOTO(out, rc);
 707
 708         request = ptlrpc_request_alloc(imp, &RQF_MDS_CONNECT);
 709         if (request == NULL)
 710                 GOTO(out, rc = -ENOMEM);
 711
 712         rc = ptlrpc_request_bufs_pack(request, LUSTRE_OBD_VERSION,
 713                                       imp->imp_connect_op, bufs, NULL);
 714         if (rc) {
 715                 ptlrpc_request_free(request);
 716                 GOTO(out, rc);
 717         }
 718
 719         /* Report the rpc service time to the server so that it knows how long
 720          * to wait for clients to join recovery */
 721         lustre_msg_set_service_time(request->rq_reqmsg,
 722                                     at_timeout2est(request->rq_timeout));
 723
 724         /* The amount of time we give the server to process the connect req.
 725          * import_select_connection will increase the net latency on
 726          * repeated reconnect attempts to cover slow networks.
 727          * We override/ignore the server rpc completion estimate here,
 728          * which may be large if this is a reconnect attempt */
 729         request->rq_timeout = INITIAL_CONNECT_TIMEOUT;
 730         lustre_msg_set_timeout(request->rq_reqmsg, request->rq_timeout);
 731
 732         request->rq_no_resend = request->rq_no_delay = 1;
 733         request->rq_send_state = LUSTRE_IMP_CONNECTING;
 734         /* Allow a slightly larger reply for future growth compatibility */
 735         req_capsule_set_size(&request->rq_pill, &RMF_CONNECT_DATA, RCL_SERVER,
 736                              sizeof(struct obd_connect_data)+16*sizeof(__u64));
 737         ptlrpc_request_set_replen(request);
 738         request->rq_interpret_reply = ptlrpc_connect_interpret;
 739
 740         CLASSERT(sizeof (*aa) <= sizeof (request->rq_async_args));
 741         aa = ptlrpc_req_async_args(request);
 742         memset(aa, 0, sizeof *aa);
 743
 744         aa->pcaa_peer_committed = committed_before_reconnect;
 745         aa->pcaa_initial_connect = initial_connect;
 746
 747         if (aa->pcaa_initial_connect) {
 748                 spin_lock(&imp->imp_lock);
 749                 imp->imp_replayable = 1;
 750                 spin_unlock(&imp->imp_lock);
 751                 lustre_msg_add_op_flags(request->rq_reqmsg,
 752                                         MSG_CONNECT_INITIAL);
 753         }
 754
 755         if (set_transno)
 756                 lustre_msg_add_op_flags(request->rq_reqmsg,
 757                                         MSG_CONNECT_TRANSNO);
 758
 759         DEBUG_REQ(D_RPCTRACE, request, "(re)connect request (timeout %d)",
 760                   request->rq_timeout);
 761         ptlrpcd_add_req(request, PDL_POLICY_ROUND, -1);
 762         rc = 0;
 763 out:
 764         if (rc != 0) {
 765                 IMPORT_SET_STATE(imp, LUSTRE_IMP_DISCON);
 766         }
 767
 768         RETURN(rc);
 769 }
 770 EXPORT_SYMBOL(ptlrpc_connect_import);
 771
 772 static void ptlrpc_maybe_ping_import_soon(struct obd_import *imp)
 773 {
 774         int force_verify;
 775
 776         spin_lock(&imp->imp_lock);
 777         force_verify = imp->imp_force_verify != 0;
 778         spin_unlock(&imp->imp_lock);
 779
 780         if (force_verify)
 781                 ptlrpc_pinger_wake_up();
 782 }
 783
 784 static int ptlrpc_busy_reconnect(int rc)
 785 {
 786         return (rc == -EBUSY) || (rc == -EAGAIN);
 787 }
 788
 789 static int ptlrpc_connect_set_flags(struct obd_import *imp,
 790                                      struct obd_connect_data *ocd,
 791                                      __u64 old_connect_flags,
 792                                      struct obd_export *exp, int init_connect)
 793 {
 794         static bool warned;
 795         struct client_obd *cli = &imp->imp_obd->u.cli;
 796
 797         if ((imp->imp_connect_flags_orig & OBD_CONNECT_IBITS) &&
 798             !(ocd->ocd_connect_flags & OBD_CONNECT_IBITS)) {
 799                 LCONSOLE_WARN("%s: MDS %s does not support ibits "
 800                               "lock, either very old or invalid: "
 801                               "requested "LPX64", replied "LPX64"\n",
 802                               imp->imp_obd->obd_name,
 803                               imp->imp_connection->c_remote_uuid.uuid,
 804                               imp->imp_connect_flags_orig,
 805                               ocd->ocd_connect_flags);
 806                 return -EPROTO;
 807         }
 808
 809         spin_lock(&imp->imp_lock);
 810         list_del(&imp->imp_conn_current->oic_item);
 811         list_add(&imp->imp_conn_current->oic_item,
 812                  &imp->imp_conn_list);
 813         imp->imp_last_success_conn =
 814                 imp->imp_conn_current->oic_last_attempt;
 815
 816         spin_unlock(&imp->imp_lock);
 817
 818
 819         if (!warned && (ocd->ocd_connect_flags & OBD_CONNECT_VERSION) &&
 820             (ocd->ocd_version > LUSTRE_VERSION_CODE +
 821                                 LUSTRE_VERSION_OFFSET_WARN ||
 822              ocd->ocd_version < LUSTRE_VERSION_CODE -
 823                                 LUSTRE_VERSION_OFFSET_WARN)) {
 824                 /* Sigh, some compilers do not like #ifdef in the middle
 825                    of macro arguments */
 826                 const char *older = "older than client. "
 827                                     "Consider upgrading server";
 828                 const char *newer = "newer than client. "
 829                                     "Consider recompiling application";
 830
 831                 LCONSOLE_WARN("Server %s version (%d.%d.%d.%d) "
 832                               "is much %s (%s)\n",
 833                               obd2cli_tgt(imp->imp_obd),
 834                               OBD_OCD_VERSION_MAJOR(ocd->ocd_version),
 835                               OBD_OCD_VERSION_MINOR(ocd->ocd_version),
 836                               OBD_OCD_VERSION_PATCH(ocd->ocd_version),
 837                               OBD_OCD_VERSION_FIX(ocd->ocd_version),
 838                               ocd->ocd_version > LUSTRE_VERSION_CODE ?
 839                               newer : older, LUSTRE_VERSION_STRING);
 840                 warned = true;
 841         }
 842
 843 #if LUSTRE_VERSION_CODE < OBD_OCD_VERSION(3, 0, 53, 0)
 844         /* Check if server has LU-1252 fix applied to not always swab
 845          * the IR MNE entries. Do this only once per connection.  This
 846          * fixup is version-limited, because we don't want to carry the
 847          * OBD_CONNECT_MNE_SWAB flag around forever, just so long as we
 848          * need interop with unpatched 2.2 servers.  For newer servers,
 849          * the client will do MNE swabbing only as needed.  LU-1644 */
 850         if (unlikely((ocd->ocd_connect_flags & OBD_CONNECT_VERSION) &&
 851                      !(ocd->ocd_connect_flags & OBD_CONNECT_MNE_SWAB) &&
 852                      OBD_OCD_VERSION_MAJOR(ocd->ocd_version) == 2 &&
 853                      OBD_OCD_VERSION_MINOR(ocd->ocd_version) == 2 &&
 854                      OBD_OCD_VERSION_PATCH(ocd->ocd_version) < 55 &&
 855                      strcmp(imp->imp_obd->obd_type->typ_name,
 856                             LUSTRE_MGC_NAME) == 0))
 857                 imp->imp_need_mne_swab = 1;
 858         else /* clear if server was upgraded since last connect */
 859                 imp->imp_need_mne_swab = 0;
 860 #endif
 861
 862         if (ocd->ocd_connect_flags & OBD_CONNECT_CKSUM) {
 863                 /* We sent to the server ocd_cksum_types with bits set
 864                  * for algorithms we understand. The server masked off
 865                  * the checksum types it doesn't support */
 866                 if ((ocd->ocd_cksum_types &
 867                      cksum_types_supported_client()) == 0) {
 868                         LCONSOLE_WARN("The negotiation of the checksum "
 869                                       "alogrithm to use with server %s "
 870                                       "failed (%x/%x), disabling "
 871                                       "checksums\n",
 872                                       obd2cli_tgt(imp->imp_obd),
 873                                       ocd->ocd_cksum_types,
 874                                       cksum_types_supported_client());
 875                         cli->cl_checksum = 0;
 876                         cli->cl_supp_cksum_types = OBD_CKSUM_ADLER;
 877                 } else {
 878                         cli->cl_supp_cksum_types = ocd->ocd_cksum_types;
 879                 }
 880         } else {
 881                 /* The server does not support OBD_CONNECT_CKSUM.
 882                  * Enforce ADLER for backward compatibility*/
 883                 cli->cl_supp_cksum_types = OBD_CKSUM_ADLER;
 884         }
 885         cli->cl_cksum_type = cksum_type_select(cli->cl_supp_cksum_types);
 886
 887         if (ocd->ocd_connect_flags & OBD_CONNECT_BRW_SIZE)
 888                 cli->cl_max_pages_per_rpc =
 889                         min(ocd->ocd_brw_size >> PAGE_CACHE_SHIFT,
 890                             cli->cl_max_pages_per_rpc);
 891         else if (imp->imp_connect_op == MDS_CONNECT ||
 892                  imp->imp_connect_op == MGS_CONNECT)
 893                 cli->cl_max_pages_per_rpc = 1;
 894
 895         LASSERT((cli->cl_max_pages_per_rpc <= PTLRPC_MAX_BRW_PAGES) &&
 896                 (cli->cl_max_pages_per_rpc > 0));
 897
 898         client_adjust_max_dirty(cli);
 899
 900
 901         /* Reset ns_connect_flags only for initial connect. It might be
 902          * changed in while using FS and if we reset it in reconnect
 903          * this leads to losing user settings done before such as
 904          * disable lru_resize, etc. */
 905         if (old_connect_flags != exp_connect_flags(exp) || init_connect) {
 906                 CDEBUG(D_HA, "%s: Resetting ns_connect_flags to server "
 907                              "flags: "LPX64"\n", imp->imp_obd->obd_name,
 908                              ocd->ocd_connect_flags);
 909                 imp->imp_obd->obd_namespace->ns_connect_flags =
 910                         ocd->ocd_connect_flags;
 911                 imp->imp_obd->obd_namespace->ns_orig_connect_flags =
 912                         ocd->ocd_connect_flags;
 913         }
 914
 915         if (ocd->ocd_connect_flags & OBD_CONNECT_AT)
 916                 /* We need a per-message support flag, because
 917                  * a. we don't know if the incoming connect reply
 918                  *    supports AT or not (in reply_in_callback)
 919                  *    until we unpack it.
 920                  * b. failovered server means export and flags are gone
 921                  *    (in ptlrpc_send_reply).
 922                  *    Can only be set when we know AT is supported at
 923                  *    both ends */
 924                 imp->imp_msghdr_flags |= MSGHDR_AT_SUPPORT;
 925         else
 926                 imp->imp_msghdr_flags &= ~MSGHDR_AT_SUPPORT;
 927
 928         imp->imp_msghdr_flags |= MSGHDR_CKSUM_INCOMPAT18;
 929
 930         return 0;
 931 }
 932
 933 /**
 934  * interpret_reply callback for connect RPCs.
 935  * Looks into returned status of connect operation and decides
 936  * what to do with the import - i.e enter recovery, promote it to
 937  * full state for normal operations of disconnect it due to an error.
 938  */
 939 static int ptlrpc_connect_interpret(const struct lu_env *env,
 940                                     struct ptlrpc_request *request,
 941                                     void *data, int rc)
 942 {
 943         struct ptlrpc_connect_async_args *aa = data;
 944         struct obd_import *imp = request->rq_import;
 945         struct lustre_handle old_hdl;
 946         __u64 old_connect_flags;
 947         int msg_flags;
 948         struct obd_connect_data *ocd;
 949         struct obd_export *exp;
 950         int ret;
 951         ENTRY;
 952
 953         spin_lock(&imp->imp_lock);
 954         if (imp->imp_state == LUSTRE_IMP_CLOSED) {
 955                 imp->imp_connect_tried = 1;
 956                 spin_unlock(&imp->imp_lock);
 957                 RETURN(0);
 958         }
 959
 960         if (rc) {
 961                 /* if this reconnect to busy export - not need select new target
 962                  * for connecting*/
 963                 imp->imp_force_reconnect = ptlrpc_busy_reconnect(rc);
 964                 spin_unlock(&imp->imp_lock);
 965                 ptlrpc_maybe_ping_import_soon(imp);
 966                 GOTO(out, rc);
 967         }
 968         spin_unlock(&imp->imp_lock);
 969
 970         LASSERT(imp->imp_conn_current);
 971
 972         msg_flags = lustre_msg_get_op_flags(request->rq_repmsg);
 973
 974         ret = req_capsule_get_size(&request->rq_pill, &RMF_CONNECT_DATA,
 975                                    RCL_SERVER);
 976         /* server replied obd_connect_data is always bigger */
 977         ocd = req_capsule_server_sized_get(&request->rq_pill,
 978                                            &RMF_CONNECT_DATA, ret);
 979
 980         if (ocd == NULL) {
 981                 CERROR("%s: no connect data from server\n",
 982                        imp->imp_obd->obd_name);
 983                 rc = -EPROTO;
 984                 GOTO(out, rc);
 985         }
 986
 987         spin_lock(&imp->imp_lock);
 988
 989         /* All imports are pingable */
 990         imp->imp_pingable = 1;
 991         imp->imp_force_reconnect = 0;
 992         imp->imp_force_verify = 0;
 993
 994         imp->imp_connect_data = *ocd;
 995
 996         CDEBUG(D_HA, "%s: connect to target with instance %u\n",
 997                imp->imp_obd->obd_name, ocd->ocd_instance);
 998         exp = class_conn2export(&imp->imp_dlm_handle);
 999
1000         spin_unlock(&imp->imp_lock);
1001
1002         /* check that server granted subset of flags we asked for. */
1003         if ((ocd->ocd_connect_flags & imp->imp_connect_flags_orig) !=
1004             ocd->ocd_connect_flags) {
1005                 CERROR("%s: Server didn't granted asked subset of flags: "
1006                        "asked="LPX64" grranted="LPX64"\n",
1007                        imp->imp_obd->obd_name,imp->imp_connect_flags_orig,
1008                        ocd->ocd_connect_flags);
1009                 GOTO(out, rc = -EPROTO);
1010         }
1011
1012         if (!(imp->imp_connect_flags_orig & OBD_CONNECT_LIGHTWEIGHT) &&
1013             (imp->imp_connect_flags_orig & OBD_CONNECT_MDS_MDS) &&
1014             (imp->imp_connect_flags_orig & OBD_CONNECT_FID) &&
1015             (ocd->ocd_connect_flags & OBD_CONNECT_VERSION)) {
1016                 __u32 major = OBD_OCD_VERSION_MAJOR(ocd->ocd_version);
1017                 __u32 minor = OBD_OCD_VERSION_MINOR(ocd->ocd_version);
1018                 __u32 patch = OBD_OCD_VERSION_PATCH(ocd->ocd_version);
1019
1020                 /* We do not support the MDT-MDT interoperations with
1021                  * different version MDT because of protocol changes. */
1022                 if (unlikely(major != LUSTRE_MAJOR ||
1023                              minor != LUSTRE_MINOR ||
1024                              abs(patch - LUSTRE_PATCH) > 3)) {
1025                         LCONSOLE_WARN("%s: import %p (%u.%u.%u.%u) tried the "
1026                                       "connection to different version MDT "
1027                                       "(%d.%d.%d.%d) %s\n",
1028                                       imp->imp_obd->obd_name, imp, LUSTRE_MAJOR,
1029                                       LUSTRE_MINOR, LUSTRE_PATCH, LUSTRE_FIX,
1030                                       major, minor, patch,
1031                                       OBD_OCD_VERSION_FIX(ocd->ocd_version),
1032                                       imp->imp_connection->c_remote_uuid.uuid);
1033
1034                         GOTO(out, rc = -EPROTO);
1035                 }
1036         }
1037
1038         if (!exp) {
1039                 /* This could happen if export is cleaned during the
1040                    connect attempt */
1041                 CERROR("%s: missing export after connect\n",
1042                        imp->imp_obd->obd_name);
1043                 GOTO(out, rc = -ENODEV);
1044         }
1045         old_connect_flags = exp_connect_flags(exp);
1046         exp->exp_connect_data = *ocd;
1047         imp->imp_obd->obd_self_export->exp_connect_data = *ocd;
1048
1049         /* The net statistics after (re-)connect is not valid anymore,
1050          * because may reflect other routing, etc. */
1051         at_init(&imp->imp_at.iat_net_latency, 0, 0);
1052         ptlrpc_at_adj_net_latency(request,
1053                         lustre_msg_get_service_time(request->rq_repmsg));
1054
1055         /* Import flags should be updated before waking import at FULL state */
1056         rc = ptlrpc_connect_set_flags(imp, ocd, old_connect_flags, exp,
1057                                  aa->pcaa_initial_connect);
1058         class_export_put(exp);
1059         if (rc != 0)
1060                 GOTO(out, rc);
1061
1062         obd_import_event(imp->imp_obd, imp, IMP_EVENT_OCD);
1063
1064         if (aa->pcaa_initial_connect) {
1065                 spin_lock(&imp->imp_lock);
1066                 if (msg_flags & MSG_CONNECT_REPLAYABLE) {
1067                         imp->imp_replayable = 1;
1068                         spin_unlock(&imp->imp_lock);
1069                         CDEBUG(D_HA, "connected to replayable target: %s\n",
1070                                obd2cli_tgt(imp->imp_obd));
1071                 } else {
1072                         imp->imp_replayable = 0;
1073                         spin_unlock(&imp->imp_lock);
1074                 }
1075
1076                 /* if applies, adjust the imp->imp_msg_magic here
1077                  * according to reply flags */
1078
1079                 imp->imp_remote_handle =
1080                                 *lustre_msg_get_handle(request->rq_repmsg);
1081
1082                 /* Initial connects are allowed for clients with non-random
1083                  * uuids when servers are in recovery.  Simply signal the
1084                  * servers replay is complete and wait in REPLAY_WAIT. */
1085                 if (msg_flags & MSG_CONNECT_RECOVERING) {
1086                         CDEBUG(D_HA, "connect to %s during recovery\n",
1087                                obd2cli_tgt(imp->imp_obd));
1088                         IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY_LOCKS);
1089                 } else {
1090                         IMPORT_SET_STATE(imp, LUSTRE_IMP_FULL);
1091                         ptlrpc_activate_import(imp);
1092                 }
1093
1094                 GOTO(finish, rc = 0);
1095         }
1096
1097         /* Determine what recovery state to move the import to. */
1098         if (MSG_CONNECT_RECONNECT & msg_flags) {
1099                 memset(&old_hdl, 0, sizeof(old_hdl));
1100                 if (!memcmp(&old_hdl, lustre_msg_get_handle(request->rq_repmsg),
1101                             sizeof (old_hdl))) {
1102                         LCONSOLE_WARN("Reconnect to %s (at @%s) failed due "
1103                                       "bad handle "LPX64"\n",
1104                                       obd2cli_tgt(imp->imp_obd),
1105                                       imp->imp_connection->c_remote_uuid.uuid,
1106                                       imp->imp_dlm_handle.cookie);
1107                         GOTO(out, rc = -ENOTCONN);
1108                 }
1109
1110                 if (memcmp(&imp->imp_remote_handle,
1111                            lustre_msg_get_handle(request->rq_repmsg),
1112                            sizeof(imp->imp_remote_handle))) {
1113                         int level = msg_flags & MSG_CONNECT_RECOVERING ?
1114                                 D_HA : D_WARNING;
1115
1116                         /* Bug 16611/14775: if server handle have changed,
1117                          * that means some sort of disconnection happened.
1118                          * If the server is not in recovery, that also means it
1119                          * already erased all of our state because of previous
1120                          * eviction. If it is in recovery - we are safe to
1121                          * participate since we can reestablish all of our state
1122                          * with server again */
1123                         if ((MSG_CONNECT_RECOVERING & msg_flags)) {
1124                                 CDEBUG(level,"%s@%s changed server handle from "
1125                                        LPX64" to "LPX64
1126                                        " but is still in recovery\n",
1127                                        obd2cli_tgt(imp->imp_obd),
1128                                        imp->imp_connection->c_remote_uuid.uuid,
1129                                        imp->imp_remote_handle.cookie,
1130                                        lustre_msg_get_handle(
1131                                        request->rq_repmsg)->cookie);
1132                         } else {
1133                                 LCONSOLE_WARN("Evicted from %s (at %s) "
1134                                               "after server handle changed from "
1135                                               LPX64" to "LPX64"\n",
1136                                               obd2cli_tgt(imp->imp_obd),
1137                                               imp->imp_connection-> \
1138                                               c_remote_uuid.uuid,
1139                                               imp->imp_remote_handle.cookie,
1140                                               lustre_msg_get_handle(
1141                                               request->rq_repmsg)->cookie);
1142                         }
1143
1144
1145                         imp->imp_remote_handle =
1146                                      *lustre_msg_get_handle(request->rq_repmsg);
1147
1148                         if (!(MSG_CONNECT_RECOVERING & msg_flags)) {
1149                                 IMPORT_SET_STATE(imp, LUSTRE_IMP_EVICTED);
1150                                 GOTO(finish, rc = 0);
1151                         }
1152
1153                 } else {
1154                         CDEBUG(D_HA, "reconnected to %s@%s after partition\n",
1155                                obd2cli_tgt(imp->imp_obd),
1156                                imp->imp_connection->c_remote_uuid.uuid);
1157                 }
1158
1159                 if (imp->imp_invalid) {
1160                         CDEBUG(D_HA, "%s: reconnected but import is invalid; "
1161                                "marking evicted\n", imp->imp_obd->obd_name);
1162                         IMPORT_SET_STATE(imp, LUSTRE_IMP_EVICTED);
1163                 } else if (MSG_CONNECT_RECOVERING & msg_flags) {
1164                         CDEBUG(D_HA, "%s: reconnected to %s during replay\n",
1165                                imp->imp_obd->obd_name,
1166                                obd2cli_tgt(imp->imp_obd));
1167
1168                         spin_lock(&imp->imp_lock);
1169                         imp->imp_resend_replay = 1;
1170                         spin_unlock(&imp->imp_lock);
1171
1172                         IMPORT_SET_STATE(imp, imp->imp_replay_state);
1173                 } else {
1174                         IMPORT_SET_STATE(imp, LUSTRE_IMP_RECOVER);
1175                 }
1176         } else if ((MSG_CONNECT_RECOVERING & msg_flags) && !imp->imp_invalid) {
1177                 LASSERT(imp->imp_replayable);
1178                 imp->imp_remote_handle =
1179                                 *lustre_msg_get_handle(request->rq_repmsg);
1180                 imp->imp_last_replay_transno = 0;
1181                 IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY);
1182         } else {
1183                 DEBUG_REQ(D_HA, request, "%s: evicting (reconnect/recover flags"
1184                           " not set: %x)", imp->imp_obd->obd_name, msg_flags);
1185                 imp->imp_remote_handle =
1186                                 *lustre_msg_get_handle(request->rq_repmsg);
1187                 IMPORT_SET_STATE(imp, LUSTRE_IMP_EVICTED);
1188         }
1189
1190         /* Sanity checks for a reconnected import. */
1191         if (!(imp->imp_replayable) != !(msg_flags & MSG_CONNECT_REPLAYABLE)) {
1192                 CERROR("imp_replayable flag does not match server "
1193                        "after reconnect. We should LBUG right here.\n");
1194         }
1195
1196         if (lustre_msg_get_last_committed(request->rq_repmsg) > 0 &&
1197             lustre_msg_get_last_committed(request->rq_repmsg) <
1198             aa->pcaa_peer_committed) {
1199                 CERROR("%s went back in time (transno "LPD64
1200                        " was previously committed, server now claims "LPD64
1201                        ")!  See https://bugzilla.lustre.org/show_bug.cgi?"
1202                        "id=9646\n",
1203                        obd2cli_tgt(imp->imp_obd), aa->pcaa_peer_committed,
1204                        lustre_msg_get_last_committed(request->rq_repmsg));
1205         }
1206
1207 finish:
1208         rc = ptlrpc_import_recovery_state_machine(imp);
1209         if (rc == -ENOTCONN) {
1210                 CDEBUG(D_HA, "evicted/aborted by %s@%s during recovery;"
1211                        "invalidating and reconnecting\n",
1212                        obd2cli_tgt(imp->imp_obd),
1213                        imp->imp_connection->c_remote_uuid.uuid);
1214                 ptlrpc_connect_import(imp);
1215                 imp->imp_connect_tried = 1;
1216                 RETURN(0);
1217         }
1218
1219 out:
1220         imp->imp_connect_tried = 1;
1221
1222         if (rc != 0) {
1223                 IMPORT_SET_STATE(imp, LUSTRE_IMP_DISCON);
1224                 if (rc == -EACCES) {
1225                         /*
1226                          * Give up trying to reconnect
1227                          * EACCES means client has no permission for connection
1228                          */
1229                         imp->imp_obd->obd_no_recov = 1;
1230                         ptlrpc_deactivate_import(imp);
1231                 }
1232
1233                 if (rc == -EPROTO) {
1234                         struct obd_connect_data *ocd;
1235
1236                         /* reply message might not be ready */
1237                         if (request->rq_repmsg == NULL)
1238                                 RETURN(-EPROTO);
1239
1240                         ocd = req_capsule_server_get(&request->rq_pill,
1241                                                      &RMF_CONNECT_DATA);
1242                         if (ocd &&
1243                             (ocd->ocd_connect_flags & OBD_CONNECT_VERSION) &&
1244                             (ocd->ocd_version != LUSTRE_VERSION_CODE)) {
1245                            /* Actually servers are only supposed to refuse
1246                               connection from liblustre clients, so we should
1247                               never see this from VFS context */
1248                                 LCONSOLE_ERROR_MSG(0x16a, "Server %s version "
1249                                         "(%d.%d.%d.%d)"
1250                                         " refused connection from this client "
1251                                         "with an incompatible version (%s).  "
1252                                         "Client must be recompiled\n",
1253                                         obd2cli_tgt(imp->imp_obd),
1254                                         OBD_OCD_VERSION_MAJOR(ocd->ocd_version),
1255                                         OBD_OCD_VERSION_MINOR(ocd->ocd_version),
1256                                         OBD_OCD_VERSION_PATCH(ocd->ocd_version),
1257                                         OBD_OCD_VERSION_FIX(ocd->ocd_version),
1258                                         LUSTRE_VERSION_STRING);
1259                                 ptlrpc_deactivate_import(imp);
1260                                 IMPORT_SET_STATE(imp, LUSTRE_IMP_CLOSED);
1261                         }
1262                         RETURN(-EPROTO);
1263                 }
1264
1265                 ptlrpc_maybe_ping_import_soon(imp);
1266
1267                 CDEBUG(D_HA, "recovery of %s on %s failed (%d)\n",
1268                        obd2cli_tgt(imp->imp_obd),
1269                        (char *)imp->imp_connection->c_remote_uuid.uuid, rc);
1270         }
1271
1272         wake_up_all(&imp->imp_recovery_waitq);
1273         RETURN(rc);
1274 }
1275
1276 /**
1277  * interpret callback for "completed replay" RPCs.
1278  * \see signal_completed_replay
1279  */
1280 static int completed_replay_interpret(const struct lu_env *env,
1281                                       struct ptlrpc_request *req,
1282                                       void * data, int rc)
1283 {
1284         ENTRY;
1285         atomic_dec(&req->rq_import->imp_replay_inflight);
1286         if (req->rq_status == 0 &&
1287             !req->rq_import->imp_vbr_failed) {
1288                 ptlrpc_import_recovery_state_machine(req->rq_import);
1289         } else {
1290                 if (req->rq_import->imp_vbr_failed) {
1291                         CDEBUG(D_WARNING,
1292                                "%s: version recovery fails, reconnecting\n",
1293                                req->rq_import->imp_obd->obd_name);
1294                 } else {
1295                         CDEBUG(D_HA, "%s: LAST_REPLAY message error: %d, "
1296                                      "reconnecting\n",
1297                                req->rq_import->imp_obd->obd_name,
1298                                req->rq_status);
1299                 }
1300                 ptlrpc_connect_import(req->rq_import);
1301         }
1302
1303         RETURN(0);
1304 }
1305
1306 /**
1307  * Let server know that we have no requests to replay anymore.
1308  * Achieved by just sending a PING request
1309  */
1310 static int signal_completed_replay(struct obd_import *imp)
1311 {
1312         struct ptlrpc_request *req;
1313         ENTRY;
1314
1315         if (unlikely(OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_FINISH_REPLAY)))
1316                 RETURN(0);
1317
1318         LASSERT(atomic_read(&imp->imp_replay_inflight) == 0);
1319         atomic_inc(&imp->imp_replay_inflight);
1320
1321         req = ptlrpc_request_alloc_pack(imp, &RQF_OBD_PING, LUSTRE_OBD_VERSION,
1322                                         OBD_PING);
1323         if (req == NULL) {
1324                 atomic_dec(&imp->imp_replay_inflight);
1325                 RETURN(-ENOMEM);
1326         }
1327
1328         ptlrpc_request_set_replen(req);
1329         req->rq_send_state = LUSTRE_IMP_REPLAY_WAIT;
1330         lustre_msg_add_flags(req->rq_reqmsg,
1331                              MSG_LOCK_REPLAY_DONE | MSG_REQ_REPLAY_DONE);
1332         if (AT_OFF)
1333                 req->rq_timeout *= 3;
1334         req->rq_interpret_reply = completed_replay_interpret;
1335
1336         ptlrpcd_add_req(req, PDL_POLICY_ROUND, -1);
1337         RETURN(0);
1338 }
1339
1340 /**
1341  * In kernel code all import invalidation happens in its own
1342  * separate thread, so that whatever application happened to encounter
1343  * a problem could still be killed or otherwise continue
1344  */
1345 static int ptlrpc_invalidate_import_thread(void *data)
1346 {
1347         struct obd_import *imp = data;
1348
1349         ENTRY;
1350
1351         unshare_fs_struct();
1352
1353         CDEBUG(D_HA, "thread invalidate import %s to %s@%s\n",
1354                imp->imp_obd->obd_name, obd2cli_tgt(imp->imp_obd),
1355                imp->imp_connection->c_remote_uuid.uuid);
1356
1357         ptlrpc_invalidate_import(imp);
1358
1359         if (obd_dump_on_eviction) {
1360                 CERROR("dump the log upon eviction\n");
1361                 libcfs_debug_dumplog();
1362         }
1363
1364         IMPORT_SET_STATE(imp, LUSTRE_IMP_RECOVER);
1365         ptlrpc_import_recovery_state_machine(imp);
1366
1367         class_import_put(imp);
1368         RETURN(0);
1369 }
1370
1371 /**
1372  * This is the state machine for client-side recovery on import.
1373  *
1374  * Typicaly we have two possibly paths. If we came to server and it is not
1375  * in recovery, we just enter IMP_EVICTED state, invalidate our import
1376  * state and reconnect from scratch.
1377  * If we came to server that is in recovery, we enter IMP_REPLAY import state.
1378  * We go through our list of requests to replay and send them to server one by
1379  * one.
1380  * After sending all request from the list we change import state to
1381  * IMP_REPLAY_LOCKS and re-request all the locks we believe we have from server
1382  * and also all the locks we don't yet have and wait for server to grant us.
1383  * After that we send a special "replay completed" request and change import
1384  * state to IMP_REPLAY_WAIT.
1385  * Upon receiving reply to that "replay completed" RPC we enter IMP_RECOVER
1386  * state and resend all requests from sending list.
1387  * After that we promote import to FULL state and send all delayed requests
1388  * and import is fully operational after that.
1389  *
1390  */
1391 int ptlrpc_import_recovery_state_machine(struct obd_import *imp)
1392 {
1393         int rc = 0;
1394         int inflight;
1395         char *target_start;
1396         int target_len;
1397
1398         ENTRY;
1399         if (imp->imp_state == LUSTRE_IMP_EVICTED) {
1400                 deuuidify(obd2cli_tgt(imp->imp_obd), NULL,
1401                           &target_start, &target_len);
1402                 /* Don't care about MGC eviction */
1403                 if (strcmp(imp->imp_obd->obd_type->typ_name,
1404                            LUSTRE_MGC_NAME) != 0) {
1405                         LCONSOLE_ERROR_MSG(0x167, "%s: This client was evicted "
1406                                            "by %.*s; in progress operations "
1407                                            "using this service will fail.\n",
1408                                            imp->imp_obd->obd_name, target_len,
1409                                            target_start);
1410                 }
1411                 CDEBUG(D_HA, "evicted from %s@%s; invalidating\n",
1412                        obd2cli_tgt(imp->imp_obd),
1413                        imp->imp_connection->c_remote_uuid.uuid);
1414                 /* reset vbr_failed flag upon eviction */
1415                 spin_lock(&imp->imp_lock);
1416                 imp->imp_vbr_failed = 0;
1417                 spin_unlock(&imp->imp_lock);
1418
1419                 {
1420                 struct task_struct *task;
1421                 /* bug 17802:  XXX client_disconnect_export vs connect request
1422                  * race. if client is evicted at this time then we start
1423                  * invalidate thread without reference to import and import can
1424                  * be freed at same time. */
1425                 class_import_get(imp);
1426                 task = kthread_run(ptlrpc_invalidate_import_thread, imp,
1427                                      "ll_imp_inval");
1428                 if (IS_ERR(task)) {
1429                         class_import_put(imp);
1430                         CERROR("error starting invalidate thread: %d\n", rc);
1431                         rc = PTR_ERR(task);
1432                 } else {
1433                         rc = 0;
1434                 }
1435                 RETURN(rc);
1436                 }
1437         }
1438
1439         if (imp->imp_state == LUSTRE_IMP_REPLAY) {
1440                 CDEBUG(D_HA, "replay requested by %s\n",
1441                        obd2cli_tgt(imp->imp_obd));
1442                 rc = ptlrpc_replay_next(imp, &inflight);
1443                 if (inflight == 0 &&
1444                     atomic_read(&imp->imp_replay_inflight) == 0) {
1445                         IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY_LOCKS);
1446                         rc = ldlm_replay_locks(imp);
1447                         if (rc)
1448                                 GOTO(out, rc);
1449                 }
1450                 rc = 0;
1451         }
1452
1453         if (imp->imp_state == LUSTRE_IMP_REPLAY_LOCKS) {
1454                 if (atomic_read(&imp->imp_replay_inflight) == 0) {
1455                         IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY_WAIT);
1456                         rc = signal_completed_replay(imp);
1457                         if (rc)
1458                                 GOTO(out, rc);
1459                 }
1460         }
1461
1462         if (imp->imp_state == LUSTRE_IMP_REPLAY_WAIT) {
1463                 if (atomic_read(&imp->imp_replay_inflight) == 0) {
1464                         IMPORT_SET_STATE(imp, LUSTRE_IMP_RECOVER);
1465                 }
1466         }
1467
1468         if (imp->imp_state == LUSTRE_IMP_RECOVER) {
1469                 CDEBUG(D_HA, "reconnected to %s@%s\n",
1470                        obd2cli_tgt(imp->imp_obd),
1471                        imp->imp_connection->c_remote_uuid.uuid);
1472
1473                 rc = ptlrpc_resend(imp);
1474                 if (rc)
1475                         GOTO(out, rc);
1476                 IMPORT_SET_STATE(imp, LUSTRE_IMP_FULL);
1477                 ptlrpc_activate_import(imp);
1478
1479                 deuuidify(obd2cli_tgt(imp->imp_obd), NULL,
1480                           &target_start, &target_len);
1481                 LCONSOLE_INFO("%s: Connection restored to %.*s (at %s)\n",
1482                               imp->imp_obd->obd_name,
1483                               target_len, target_start,
1484                               libcfs_nid2str(imp->imp_connection->c_peer.nid));
1485         }
1486
1487         if (imp->imp_state == LUSTRE_IMP_FULL) {
1488                 wake_up_all(&imp->imp_recovery_waitq);
1489                 ptlrpc_wake_delayed(imp);
1490         }
1491
1492 out:
1493         RETURN(rc);
1494 }
1495
1496 int ptlrpc_disconnect_import(struct obd_import *imp, int noclose)
1497 {
1498         struct ptlrpc_request *req;
1499         int rq_opc, rc = 0;
1500         ENTRY;
1501
1502         if (imp->imp_obd->obd_force)
1503                 GOTO(set_state, rc);
1504
1505         switch (imp->imp_connect_op) {
1506         case OST_CONNECT:
1507                 rq_opc = OST_DISCONNECT;
1508                 break;
1509         case MDS_CONNECT:
1510                 rq_opc = MDS_DISCONNECT;
1511                 break;
1512         case MGS_CONNECT:
1513                 rq_opc = MGS_DISCONNECT;
1514                 break;
1515         default:
1516                 rc = -EINVAL;
1517                 CERROR("%s: don't know how to disconnect from %s "
1518                        "(connect_op %d): rc = %d\n",
1519                        imp->imp_obd->obd_name, obd2cli_tgt(imp->imp_obd),
1520                        imp->imp_connect_op, rc);
1521                 RETURN(rc);
1522         }
1523
1524         if (ptlrpc_import_in_recovery(imp)) {
1525                 struct l_wait_info lwi;
1526                 cfs_duration_t timeout;
1527
1528                 if (AT_OFF) {
1529                         if (imp->imp_server_timeout)
1530                                 timeout = cfs_time_seconds(obd_timeout / 2);
1531                         else
1532                                 timeout = cfs_time_seconds(obd_timeout);
1533                 } else {
1534                         int idx = import_at_get_index(imp,
1535                                 imp->imp_client->cli_request_portal);
1536                         timeout = cfs_time_seconds(
1537                                 at_get(&imp->imp_at.iat_service_estimate[idx]));
1538                 }
1539
1540                 lwi = LWI_TIMEOUT_INTR(cfs_timeout_cap(timeout),
1541                                        back_to_sleep, LWI_ON_SIGNAL_NOOP, NULL);
1542                 rc = l_wait_event(imp->imp_recovery_waitq,
1543                                   !ptlrpc_import_in_recovery(imp), &lwi);
1544
1545         }
1546
1547         spin_lock(&imp->imp_lock);
1548         if (imp->imp_state != LUSTRE_IMP_FULL)
1549                 GOTO(out, rc);
1550         spin_unlock(&imp->imp_lock);
1551
1552         req = ptlrpc_request_alloc_pack(imp, &RQF_MDS_DISCONNECT,
1553                                         LUSTRE_OBD_VERSION, rq_opc);
1554         if (req) {
1555                 /* We are disconnecting, do not retry a failed DISCONNECT rpc if
1556                  * it fails.  We can get through the above with a down server
1557                  * if the client doesn't know the server is gone yet. */
1558                 req->rq_no_resend = 1;
1559
1560                 /* We want client umounts to happen quickly, no matter the
1561                    server state... */
1562                 req->rq_timeout = min_t(int, req->rq_timeout,
1563                                         INITIAL_CONNECT_TIMEOUT);
1564
1565                 IMPORT_SET_STATE(imp, LUSTRE_IMP_CONNECTING);
1566                 req->rq_send_state =  LUSTRE_IMP_CONNECTING;
1567                 ptlrpc_request_set_replen(req);
1568                 rc = ptlrpc_queue_wait(req);
1569                 ptlrpc_req_finished(req);
1570         }
1571
1572 set_state:
1573         spin_lock(&imp->imp_lock);
1574 out:
1575         if (noclose)
1576                 IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_DISCON);
1577         else
1578                 IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_CLOSED);
1579         memset(&imp->imp_remote_handle, 0, sizeof(imp->imp_remote_handle));
1580         spin_unlock(&imp->imp_lock);
1581
1582         if (rc == -ETIMEDOUT || rc == -ENOTCONN || rc == -ESHUTDOWN)
1583                 rc = 0;
1584         RETURN(rc);
1585 }
1586 EXPORT_SYMBOL(ptlrpc_disconnect_import);
1587
1588 void ptlrpc_cleanup_imp(struct obd_import *imp)
1589 {
1590         ENTRY;
1591
1592         spin_lock(&imp->imp_lock);
1593         IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_CLOSED);
1594         imp->imp_generation++;
1595         spin_unlock(&imp->imp_lock);
1596         ptlrpc_abort_inflight(imp);
1597
1598         EXIT;
1599 }
1600
1601 /* Adaptive Timeout utils */
1602 extern unsigned int at_min, at_max, at_history;
1603
1604 /* Update at_current with the specified value (bounded by at_min and at_max),
1605  * as well as the AT history "bins".
1606  *  - Bin into timeslices using AT_BINS bins.
1607  *  - This gives us a max of the last at_history seconds without the storage,
1608  *    but still smoothing out a return to normalcy from a slow response.
1609  *  - (E.g. remember the maximum latency in each minute of the last 4 minutes.)
1610  */
1611 int at_measured(struct adaptive_timeout *at, unsigned int val)
1612 {
1613         unsigned int old = at->at_current;
1614         time_t now = cfs_time_current_sec();
1615         time_t binlimit = max_t(time_t, at_history / AT_BINS, 1);
1616
1617         LASSERT(at);
1618         CDEBUG(D_OTHER, "add %u to %p time=%lu v=%u (%u %u %u %u)\n",
1619                val, at, now - at->at_binstart, at->at_current,
1620                at->at_hist[0], at->at_hist[1], at->at_hist[2], at->at_hist[3]);
1621
1622         if (val == 0)
1623                 /* 0's don't count, because we never want our timeout to
1624                    drop to 0, and because 0 could mean an error */
1625                 return 0;
1626
1627         spin_lock(&at->at_lock);
1628
1629         if (unlikely(at->at_binstart == 0)) {
1630                 /* Special case to remove default from history */
1631                 at->at_current = val;
1632                 at->at_worst_ever = val;
1633                 at->at_worst_time = now;
1634                 at->at_hist[0] = val;
1635                 at->at_binstart = now;
1636         } else if (now - at->at_binstart < binlimit ) {
1637                 /* in bin 0 */
1638                 at->at_hist[0] = max(val, at->at_hist[0]);
1639                 at->at_current = max(val, at->at_current);
1640         } else {
1641                 int i, shift;
1642                 unsigned int maxv = val;
1643                 /* move bins over */
1644                 shift = (now - at->at_binstart) / binlimit;
1645                 LASSERT(shift > 0);
1646                 for(i = AT_BINS - 1; i >= 0; i--) {
1647                         if (i >= shift) {
1648                                 at->at_hist[i] = at->at_hist[i - shift];
1649                                 maxv = max(maxv, at->at_hist[i]);
1650                         } else {
1651                                 at->at_hist[i] = 0;
1652                         }
1653                 }
1654                 at->at_hist[0] = val;
1655                 at->at_current = maxv;
1656                 at->at_binstart += shift * binlimit;
1657         }
1658
1659         if (at->at_current > at->at_worst_ever) {
1660                 at->at_worst_ever = at->at_current;
1661                 at->at_worst_time = now;
1662         }
1663
1664         if (at->at_flags & AT_FLG_NOHIST)
1665                 /* Only keep last reported val; keeping the rest of the history
1666                    for proc only */
1667                 at->at_current = val;
1668
1669         if (at_max > 0)
1670                 at->at_current =  min(at->at_current, at_max);
1671         at->at_current =  max(at->at_current, at_min);
1672
1673         if (at->at_current != old)
1674                 CDEBUG(D_OTHER, "AT %p change: old=%u new=%u delta=%d "
1675                        "(val=%u) hist %u %u %u %u\n", at,
1676                        old, at->at_current, at->at_current - old, val,
1677                        at->at_hist[0], at->at_hist[1], at->at_hist[2],
1678                        at->at_hist[3]);
1679
1680         /* if we changed, report the old value */
1681         old = (at->at_current != old) ? old : 0;
1682
1683         spin_unlock(&at->at_lock);
1684         return old;
1685 }
1686
1687 /* Find the imp_at index for a given portal; assign if space available */
1688 int import_at_get_index(struct obd_import *imp, int portal)
1689 {
1690         struct imp_at *at = &imp->imp_at;
1691         int i;
1692
1693         for (i = 0; i < IMP_AT_MAX_PORTALS; i++) {
1694                 if (at->iat_portal[i] == portal)
1695                         return i;
1696                 if (at->iat_portal[i] == 0)
1697                         /* unused */
1698                         break;
1699         }
1700
1701         /* Not found in list, add it under a lock */
1702         spin_lock(&imp->imp_lock);
1703
1704         /* Check unused under lock */
1705         for (; i < IMP_AT_MAX_PORTALS; i++) {
1706                 if (at->iat_portal[i] == portal)
1707                         goto out;
1708                 if (at->iat_portal[i] == 0)
1709                         /* unused */
1710                         break;
1711         }
1712
1713         /* Not enough portals? */
1714         LASSERT(i < IMP_AT_MAX_PORTALS);
1715
1716         at->iat_portal[i] = portal;
1717 out:
1718         spin_unlock(&imp->imp_lock);
1719         return i;
1720 }