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 static 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
 422 void ptlrpc_fail_import(struct obd_import *imp, __u32 conn_cnt)
 423 {
 424         ENTRY;
 425
 426         LASSERT(!imp->imp_dlm_fake);
 427
 428         if (ptlrpc_set_import_discon(imp, conn_cnt)) {
 429                 if (!imp->imp_replayable) {
 430                         CDEBUG(D_HA, "import %s@%s for %s not replayable, "
 431                                "auto-deactivating\n",
 432                                obd2cli_tgt(imp->imp_obd),
 433                                imp->imp_connection->c_remote_uuid.uuid,
 434                                imp->imp_obd->obd_name);
 435                         ptlrpc_deactivate_import(imp);
 436                 }
 437
 438                 ptlrpc_pinger_force(imp);
 439         }
 440         EXIT;
 441 }
 442
 443 int ptlrpc_reconnect_import(struct obd_import *imp)
 444 {
 445 #ifdef ENABLE_PINGER
 446         struct l_wait_info lwi;
 447         int secs = cfs_time_seconds(obd_timeout);
 448         int rc;
 449
 450         ptlrpc_pinger_force(imp);
 451
 452         CDEBUG(D_HA, "%s: recovery started, waiting %u seconds\n",
 453                obd2cli_tgt(imp->imp_obd), secs);
 454
 455         lwi = LWI_TIMEOUT(secs, NULL, NULL);
 456         rc = l_wait_event(imp->imp_recovery_waitq,
 457                           !ptlrpc_import_in_recovery(imp), &lwi);
 458         CDEBUG(D_HA, "%s: recovery finished s:%s\n", obd2cli_tgt(imp->imp_obd),
 459                ptlrpc_import_state_name(imp->imp_state));
 460         return rc;
 461 #else
 462         ptlrpc_set_import_discon(imp, 0);
 463         /* Force a new connect attempt */
 464         ptlrpc_invalidate_import(imp);
 465         /* Do a fresh connect next time by zeroing the handle */
 466         ptlrpc_disconnect_import(imp, 1);
 467         /* Wait for all invalidate calls to finish */
 468         if (atomic_read(&imp->imp_inval_count) > 0) {
 469                 struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
 470                 int rc;
 471
 472                 rc = l_wait_event(imp->imp_recovery_waitq,
 473                                   (atomic_read(&imp->imp_inval_count) == 0),
 474                                   &lwi);
 475                 if (rc)
 476                         CERROR("Interrupted, inval=%d\n",
 477                                atomic_read(&imp->imp_inval_count));
 478         }
 479
 480         /* Allow reconnect attempts */
 481         imp->imp_obd->obd_no_recov = 0;
 482         /* Remove 'invalid' flag */
 483         ptlrpc_activate_import(imp);
 484         /* Attempt a new connect */
 485         ptlrpc_recover_import(imp, NULL, 0);
 486         return 0;
 487 #endif
 488 }
 489 EXPORT_SYMBOL(ptlrpc_reconnect_import);
 490
 491 /**
 492  * Connection on import \a imp is changed to another one (if more than one is
 493  * present). We typically chose connection that we have not tried to connect to
 494  * the longest
 495  */
 496 static int import_select_connection(struct obd_import *imp)
 497 {
 498         struct obd_import_conn *imp_conn = NULL, *conn;
 499         struct obd_export *dlmexp;
 500         char *target_start;
 501         int target_len, tried_all = 1;
 502         ENTRY;
 503
 504         spin_lock(&imp->imp_lock);
 505
 506         if (list_empty(&imp->imp_conn_list)) {
 507                 CERROR("%s: no connections available\n",
 508                        imp->imp_obd->obd_name);
 509                 spin_unlock(&imp->imp_lock);
 510                 RETURN(-EINVAL);
 511         }
 512
 513         list_for_each_entry(conn, &imp->imp_conn_list, oic_item) {
 514                 CDEBUG(D_HA, "%s: connect to NID %s last attempt "LPU64"\n",
 515                        imp->imp_obd->obd_name,
 516                        libcfs_nid2str(conn->oic_conn->c_peer.nid),
 517                        conn->oic_last_attempt);
 518
 519                 /* If we have not tried this connection since
 520                    the last successful attempt, go with this one */
 521                 if ((conn->oic_last_attempt == 0) ||
 522                     cfs_time_beforeq_64(conn->oic_last_attempt,
 523                                        imp->imp_last_success_conn)) {
 524                         imp_conn = conn;
 525                         tried_all = 0;
 526                         break;
 527                 }
 528
 529                 /* If all of the connections have already been tried
 530                    since the last successful connection; just choose the
 531                    least recently used */
 532                 if (!imp_conn)
 533                         imp_conn = conn;
 534                 else if (cfs_time_before_64(conn->oic_last_attempt,
 535                                             imp_conn->oic_last_attempt))
 536                         imp_conn = conn;
 537         }
 538
 539         /* if not found, simply choose the current one */
 540         if (!imp_conn || imp->imp_force_reconnect) {
 541                 LASSERT(imp->imp_conn_current);
 542                 imp_conn = imp->imp_conn_current;
 543                 tried_all = 0;
 544         }
 545         LASSERT(imp_conn->oic_conn);
 546
 547         /* If we've tried everything, and we're back to the beginning of the
 548            list, increase our timeout and try again. It will be reset when
 549            we do finally connect. (FIXME: really we should wait for all network
 550            state associated with the last connection attempt to drain before
 551            trying to reconnect on it.) */
 552         if (tried_all && (imp->imp_conn_list.next == &imp_conn->oic_item)) {
 553                 struct adaptive_timeout *at = &imp->imp_at.iat_net_latency;
 554                 if (at_get(at) < CONNECTION_SWITCH_MAX) {
 555                         at_measured(at, at_get(at) + CONNECTION_SWITCH_INC);
 556                         if (at_get(at) > CONNECTION_SWITCH_MAX)
 557                                 at_reset(at, CONNECTION_SWITCH_MAX);
 558                 }
 559                 LASSERT(imp_conn->oic_last_attempt);
 560                 CDEBUG(D_HA, "%s: tried all connections, increasing latency "
 561                         "to %ds\n", imp->imp_obd->obd_name, at_get(at));
 562         }
 563
 564         imp_conn->oic_last_attempt = cfs_time_current_64();
 565
 566         /* switch connection, don't mind if it's same as the current one */
 567         if (imp->imp_connection)
 568                 ptlrpc_connection_put(imp->imp_connection);
 569         imp->imp_connection = ptlrpc_connection_addref(imp_conn->oic_conn);
 570
 571         dlmexp =  class_conn2export(&imp->imp_dlm_handle);
 572         LASSERT(dlmexp != NULL);
 573         if (dlmexp->exp_connection)
 574                 ptlrpc_connection_put(dlmexp->exp_connection);
 575         dlmexp->exp_connection = ptlrpc_connection_addref(imp_conn->oic_conn);
 576         class_export_put(dlmexp);
 577
 578         if (imp->imp_conn_current != imp_conn) {
 579                 if (imp->imp_conn_current) {
 580                         deuuidify(obd2cli_tgt(imp->imp_obd), NULL,
 581                                   &target_start, &target_len);
 582
 583                         CDEBUG(D_HA, "%s: Connection changing to"
 584                                " %.*s (at %s)\n",
 585                                imp->imp_obd->obd_name,
 586                                target_len, target_start,
 587                                libcfs_nid2str(imp_conn->oic_conn->c_peer.nid));
 588                 }
 589
 590                 imp->imp_conn_current = imp_conn;
 591         }
 592
 593         CDEBUG(D_HA, "%s: import %p using connection %s/%s\n",
 594                imp->imp_obd->obd_name, imp, imp_conn->oic_uuid.uuid,
 595                libcfs_nid2str(imp_conn->oic_conn->c_peer.nid));
 596
 597         spin_unlock(&imp->imp_lock);
 598
 599         RETURN(0);
 600 }
 601
 602 /*
 603  * must be called under imp_lock
 604  */
 605 static int ptlrpc_first_transno(struct obd_import *imp, __u64 *transno)
 606 {
 607         struct ptlrpc_request   *req;
 608         struct list_head        *tmp;
 609
 610         /* The requests in committed_list always have smaller transnos than
 611          * the requests in replay_list */
 612         if (!list_empty(&imp->imp_committed_list)) {
 613                 tmp = imp->imp_committed_list.next;
 614                 req = list_entry(tmp, struct ptlrpc_request, rq_replay_list);
 615                 *transno = req->rq_transno;
 616                 if (req->rq_transno == 0) {
 617                         DEBUG_REQ(D_ERROR, req, "zero transno in committed_list");
 618                         LBUG();
 619                 }
 620                 return 1;
 621         }
 622         if (!list_empty(&imp->imp_replay_list)) {
 623                 tmp = imp->imp_replay_list.next;
 624                 req = list_entry(tmp, struct ptlrpc_request, rq_replay_list);
 625                 *transno = req->rq_transno;
 626                 if (req->rq_transno == 0) {
 627                         DEBUG_REQ(D_ERROR, req, "zero transno in replay_list");
 628                         LBUG();
 629                 }
 630                 return 1;
 631         }
 632         return 0;
 633 }
 634
 635 /**
 636  * Attempt to (re)connect import \a imp. This includes all preparations,
 637  * initializing CONNECT RPC request and passing it to ptlrpcd for
 638  * actual sending.
 639  * Returns 0 on success or error code.
 640  */
 641 int ptlrpc_connect_import(struct obd_import *imp)
 642 {
 643         struct obd_device *obd = imp->imp_obd;
 644         int initial_connect = 0;
 645         int set_transno = 0;
 646         __u64 committed_before_reconnect = 0;
 647         struct ptlrpc_request *request;
 648         char *bufs[] = { NULL,
 649                          obd2cli_tgt(imp->imp_obd),
 650                          obd->obd_uuid.uuid,
 651                          (char *)&imp->imp_dlm_handle,
 652                          (char *)&imp->imp_connect_data };
 653         struct ptlrpc_connect_async_args *aa;
 654         int rc;
 655         ENTRY;
 656
 657         spin_lock(&imp->imp_lock);
 658         if (imp->imp_state == LUSTRE_IMP_CLOSED) {
 659                 spin_unlock(&imp->imp_lock);
 660                 CERROR("can't connect to a closed import\n");
 661                 RETURN(-EINVAL);
 662         } else if (imp->imp_state == LUSTRE_IMP_FULL) {
 663                 spin_unlock(&imp->imp_lock);
 664                 CERROR("already connected\n");
 665                 RETURN(0);
 666         } else if (imp->imp_state == LUSTRE_IMP_CONNECTING) {
 667                 spin_unlock(&imp->imp_lock);
 668                 CERROR("already connecting\n");
 669                 RETURN(-EALREADY);
 670         }
 671
 672         IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_CONNECTING);
 673
 674         imp->imp_conn_cnt++;
 675         imp->imp_resend_replay = 0;
 676
 677         if (!lustre_handle_is_used(&imp->imp_remote_handle))
 678                 initial_connect = 1;
 679         else
 680                 committed_before_reconnect = imp->imp_peer_committed_transno;
 681
 682         set_transno = ptlrpc_first_transno(imp,
 683                                            &imp->imp_connect_data.ocd_transno);
 684         spin_unlock(&imp->imp_lock);
 685
 686         rc = import_select_connection(imp);
 687         if (rc)
 688                 GOTO(out, rc);
 689
 690         rc = sptlrpc_import_sec_adapt(imp, NULL, NULL);
 691         if (rc)
 692                 GOTO(out, rc);
 693
 694         /* Reset connect flags to the originally requested flags, in case
 695          * the server is updated on-the-fly we will get the new features. */
 696         imp->imp_connect_data.ocd_connect_flags = imp->imp_connect_flags_orig;
 697         /* Reset ocd_version each time so the server knows the exact versions */
 698         imp->imp_connect_data.ocd_version = LUSTRE_VERSION_CODE;
 699         imp->imp_msghdr_flags &= ~MSGHDR_AT_SUPPORT;
 700         imp->imp_msghdr_flags &= ~MSGHDR_CKSUM_INCOMPAT18;
 701
 702         rc = obd_reconnect(NULL, imp->imp_obd->obd_self_export, obd,
 703                            &obd->obd_uuid, &imp->imp_connect_data, NULL);
 704         if (rc)
 705                 GOTO(out, rc);
 706
 707         request = ptlrpc_request_alloc(imp, &RQF_MDS_CONNECT);
 708         if (request == NULL)
 709                 GOTO(out, rc = -ENOMEM);
 710
 711         rc = ptlrpc_request_bufs_pack(request, LUSTRE_OBD_VERSION,
 712                                       imp->imp_connect_op, bufs, NULL);
 713         if (rc) {
 714                 ptlrpc_request_free(request);
 715                 GOTO(out, rc);
 716         }
 717
 718         /* Report the rpc service time to the server so that it knows how long
 719          * to wait for clients to join recovery */
 720         lustre_msg_set_service_time(request->rq_reqmsg,
 721                                     at_timeout2est(request->rq_timeout));
 722
 723         /* The amount of time we give the server to process the connect req.
 724          * import_select_connection will increase the net latency on
 725          * repeated reconnect attempts to cover slow networks.
 726          * We override/ignore the server rpc completion estimate here,
 727          * which may be large if this is a reconnect attempt */
 728         request->rq_timeout = INITIAL_CONNECT_TIMEOUT;
 729         lustre_msg_set_timeout(request->rq_reqmsg, request->rq_timeout);
 730
 731         lustre_msg_add_op_flags(request->rq_reqmsg, MSG_CONNECT_NEXT_VER);
 732
 733         request->rq_no_resend = request->rq_no_delay = 1;
 734         request->rq_send_state = LUSTRE_IMP_CONNECTING;
 735         /* Allow a slightly larger reply for future growth compatibility */
 736         req_capsule_set_size(&request->rq_pill, &RMF_CONNECT_DATA, RCL_SERVER,
 737                              sizeof(struct obd_connect_data)+16*sizeof(__u64));
 738         ptlrpc_request_set_replen(request);
 739         request->rq_interpret_reply = ptlrpc_connect_interpret;
 740
 741         CLASSERT(sizeof (*aa) <= sizeof (request->rq_async_args));
 742         aa = ptlrpc_req_async_args(request);
 743         memset(aa, 0, sizeof *aa);
 744
 745         aa->pcaa_peer_committed = committed_before_reconnect;
 746         aa->pcaa_initial_connect = initial_connect;
 747
 748         if (aa->pcaa_initial_connect) {
 749                 spin_lock(&imp->imp_lock);
 750                 imp->imp_replayable = 1;
 751                 spin_unlock(&imp->imp_lock);
 752                 lustre_msg_add_op_flags(request->rq_reqmsg,
 753                                         MSG_CONNECT_INITIAL);
 754         }
 755
 756         if (set_transno)
 757                 lustre_msg_add_op_flags(request->rq_reqmsg,
 758                                         MSG_CONNECT_TRANSNO);
 759
 760         DEBUG_REQ(D_RPCTRACE, request, "(re)connect request (timeout %d)",
 761                   request->rq_timeout);
 762         ptlrpcd_add_req(request, PDL_POLICY_ROUND, -1);
 763         rc = 0;
 764 out:
 765         if (rc != 0) {
 766                 IMPORT_SET_STATE(imp, LUSTRE_IMP_DISCON);
 767         }
 768
 769         RETURN(rc);
 770 }
 771 EXPORT_SYMBOL(ptlrpc_connect_import);
 772
 773 static void ptlrpc_maybe_ping_import_soon(struct obd_import *imp)
 774 {
 775         int force_verify;
 776
 777         spin_lock(&imp->imp_lock);
 778         force_verify = imp->imp_force_verify != 0;
 779         spin_unlock(&imp->imp_lock);
 780
 781         if (force_verify)
 782                 ptlrpc_pinger_wake_up();
 783 }
 784
 785 static int ptlrpc_busy_reconnect(int rc)
 786 {
 787         return (rc == -EBUSY) || (rc == -EAGAIN);
 788 }
 789
 790 static int ptlrpc_connect_set_flags(struct obd_import *imp,
 791                                      struct obd_connect_data *ocd,
 792                                      __u64 old_connect_flags,
 793                                      struct obd_export *exp, int init_connect)
 794 {
 795         static bool warned;
 796         struct client_obd *cli = &imp->imp_obd->u.cli;
 797
 798         if ((imp->imp_connect_flags_orig & OBD_CONNECT_IBITS) &&
 799             !(ocd->ocd_connect_flags & OBD_CONNECT_IBITS)) {
 800                 LCONSOLE_WARN("%s: MDS %s does not support ibits "
 801                               "lock, either very old or invalid: "
 802                               "requested "LPX64", replied "LPX64"\n",
 803                               imp->imp_obd->obd_name,
 804                               imp->imp_connection->c_remote_uuid.uuid,
 805                               imp->imp_connect_flags_orig,
 806                               ocd->ocd_connect_flags);
 807                 return -EPROTO;
 808         }
 809
 810         spin_lock(&imp->imp_lock);
 811         list_del(&imp->imp_conn_current->oic_item);
 812         list_add(&imp->imp_conn_current->oic_item,
 813                  &imp->imp_conn_list);
 814         imp->imp_last_success_conn =
 815                 imp->imp_conn_current->oic_last_attempt;
 816
 817         spin_unlock(&imp->imp_lock);
 818
 819
 820         if (!warned && (ocd->ocd_connect_flags & OBD_CONNECT_VERSION) &&
 821             (ocd->ocd_version > LUSTRE_VERSION_CODE +
 822                                 LUSTRE_VERSION_OFFSET_WARN ||
 823              ocd->ocd_version < LUSTRE_VERSION_CODE -
 824                                 LUSTRE_VERSION_OFFSET_WARN)) {
 825                 /* Sigh, some compilers do not like #ifdef in the middle
 826                    of macro arguments */
 827                 const char *older = "older than client. "
 828                                     "Consider upgrading server";
 829                 const char *newer = "newer than client. "
 830                                     "Consider recompiling application";
 831
 832                 LCONSOLE_WARN("Server %s version (%d.%d.%d.%d) "
 833                               "is much %s (%s)\n",
 834                               obd2cli_tgt(imp->imp_obd),
 835                               OBD_OCD_VERSION_MAJOR(ocd->ocd_version),
 836                               OBD_OCD_VERSION_MINOR(ocd->ocd_version),
 837                               OBD_OCD_VERSION_PATCH(ocd->ocd_version),
 838                               OBD_OCD_VERSION_FIX(ocd->ocd_version),
 839                               ocd->ocd_version > LUSTRE_VERSION_CODE ?
 840                               newer : older, LUSTRE_VERSION_STRING);
 841                 warned = true;
 842         }
 843
 844 #if LUSTRE_VERSION_CODE < OBD_OCD_VERSION(3, 0, 53, 0)
 845         /* Check if server has LU-1252 fix applied to not always swab
 846          * the IR MNE entries. Do this only once per connection.  This
 847          * fixup is version-limited, because we don't want to carry the
 848          * OBD_CONNECT_MNE_SWAB flag around forever, just so long as we
 849          * need interop with unpatched 2.2 servers.  For newer servers,
 850          * the client will do MNE swabbing only as needed.  LU-1644 */
 851         if (unlikely((ocd->ocd_connect_flags & OBD_CONNECT_VERSION) &&
 852                      !(ocd->ocd_connect_flags & OBD_CONNECT_MNE_SWAB) &&
 853                      OBD_OCD_VERSION_MAJOR(ocd->ocd_version) == 2 &&
 854                      OBD_OCD_VERSION_MINOR(ocd->ocd_version) == 2 &&
 855                      OBD_OCD_VERSION_PATCH(ocd->ocd_version) < 55 &&
 856                      strcmp(imp->imp_obd->obd_type->typ_name,
 857                             LUSTRE_MGC_NAME) == 0))
 858                 imp->imp_need_mne_swab = 1;
 859         else /* clear if server was upgraded since last connect */
 860                 imp->imp_need_mne_swab = 0;
 861 #endif
 862
 863         if (ocd->ocd_connect_flags & OBD_CONNECT_CKSUM) {
 864                 /* We sent to the server ocd_cksum_types with bits set
 865                  * for algorithms we understand. The server masked off
 866                  * the checksum types it doesn't support */
 867                 if ((ocd->ocd_cksum_types &
 868                      cksum_types_supported_client()) == 0) {
 869                         LCONSOLE_WARN("The negotiation of the checksum "
 870                                       "alogrithm to use with server %s "
 871                                       "failed (%x/%x), disabling "
 872                                       "checksums\n",
 873                                       obd2cli_tgt(imp->imp_obd),
 874                                       ocd->ocd_cksum_types,
 875                                       cksum_types_supported_client());
 876                         cli->cl_checksum = 0;
 877                         cli->cl_supp_cksum_types = OBD_CKSUM_ADLER;
 878                 } else {
 879                         cli->cl_supp_cksum_types = ocd->ocd_cksum_types;
 880                 }
 881         } else {
 882                 /* The server does not support OBD_CONNECT_CKSUM.
 883                  * Enforce ADLER for backward compatibility*/
 884                 cli->cl_supp_cksum_types = OBD_CKSUM_ADLER;
 885         }
 886         cli->cl_cksum_type = cksum_type_select(cli->cl_supp_cksum_types);
 887
 888         if (ocd->ocd_connect_flags & OBD_CONNECT_BRW_SIZE)
 889                 cli->cl_max_pages_per_rpc =
 890                         min(ocd->ocd_brw_size >> PAGE_CACHE_SHIFT,
 891                             cli->cl_max_pages_per_rpc);
 892         else if (imp->imp_connect_op == MDS_CONNECT ||
 893                  imp->imp_connect_op == MGS_CONNECT)
 894                 cli->cl_max_pages_per_rpc = 1;
 895
 896         LASSERT((cli->cl_max_pages_per_rpc <= PTLRPC_MAX_BRW_PAGES) &&
 897                 (cli->cl_max_pages_per_rpc > 0));
 898
 899         client_adjust_max_dirty(cli);
 900
 901
 902         /* Reset ns_connect_flags only for initial connect. It might be
 903          * changed in while using FS and if we reset it in reconnect
 904          * this leads to losing user settings done before such as
 905          * disable lru_resize, etc. */
 906         if (old_connect_flags != exp_connect_flags(exp) || init_connect) {
 907                 CDEBUG(D_HA, "%s: Resetting ns_connect_flags to server "
 908                              "flags: "LPX64"\n", imp->imp_obd->obd_name,
 909                              ocd->ocd_connect_flags);
 910                 imp->imp_obd->obd_namespace->ns_connect_flags =
 911                         ocd->ocd_connect_flags;
 912                 imp->imp_obd->obd_namespace->ns_orig_connect_flags =
 913                         ocd->ocd_connect_flags;
 914         }
 915
 916         if ((ocd->ocd_connect_flags & OBD_CONNECT_AT) &&
 917                 (imp->imp_msg_magic == LUSTRE_MSG_MAGIC_V2))
 918                 /* We need a per-message support flag, because
 919                  * a. we don't know if the incoming connect reply
 920                  *    supports AT or not (in reply_in_callback)
 921                  *    until we unpack it.
 922                  * b. failovered server means export and flags are gone
 923                  *    (in ptlrpc_send_reply).
 924                  *    Can only be set when we know AT is supported at
 925                  *    both ends */
 926                 imp->imp_msghdr_flags |= MSGHDR_AT_SUPPORT;
 927         else
 928                 imp->imp_msghdr_flags &= ~MSGHDR_AT_SUPPORT;
 929
 930         if ((ocd->ocd_connect_flags & OBD_CONNECT_FULL20) &&
 931             (imp->imp_msg_magic == LUSTRE_MSG_MAGIC_V2))
 932                 imp->imp_msghdr_flags |= MSGHDR_CKSUM_INCOMPAT18;
 933         else
 934                 imp->imp_msghdr_flags &= ~MSGHDR_CKSUM_INCOMPAT18;
 935
 936         return 0;
 937 }
 938
 939 /**
 940  * interpret_reply callback for connect RPCs.
 941  * Looks into returned status of connect operation and decides
 942  * what to do with the import - i.e enter recovery, promote it to
 943  * full state for normal operations of disconnect it due to an error.
 944  */
 945 static int ptlrpc_connect_interpret(const struct lu_env *env,
 946                                     struct ptlrpc_request *request,
 947                                     void *data, int rc)
 948 {
 949         struct ptlrpc_connect_async_args *aa = data;
 950         struct obd_import *imp = request->rq_import;
 951         struct lustre_handle old_hdl;
 952         __u64 old_connect_flags;
 953         int msg_flags;
 954         struct obd_connect_data *ocd;
 955         struct obd_export *exp;
 956         int ret;
 957         ENTRY;
 958
 959         spin_lock(&imp->imp_lock);
 960         if (imp->imp_state == LUSTRE_IMP_CLOSED) {
 961                 imp->imp_connect_tried = 1;
 962                 spin_unlock(&imp->imp_lock);
 963                 RETURN(0);
 964         }
 965
 966         if (rc) {
 967                 /* if this reconnect to busy export - not need select new target
 968                  * for connecting*/
 969                 imp->imp_force_reconnect = ptlrpc_busy_reconnect(rc);
 970                 spin_unlock(&imp->imp_lock);
 971                 ptlrpc_maybe_ping_import_soon(imp);
 972                 GOTO(out, rc);
 973         }
 974         spin_unlock(&imp->imp_lock);
 975
 976         LASSERT(imp->imp_conn_current);
 977
 978         msg_flags = lustre_msg_get_op_flags(request->rq_repmsg);
 979
 980         ret = req_capsule_get_size(&request->rq_pill, &RMF_CONNECT_DATA,
 981                                    RCL_SERVER);
 982         /* server replied obd_connect_data is always bigger */
 983         ocd = req_capsule_server_sized_get(&request->rq_pill,
 984                                            &RMF_CONNECT_DATA, ret);
 985
 986         if (ocd == NULL) {
 987                 CERROR("%s: no connect data from server\n",
 988                        imp->imp_obd->obd_name);
 989                 rc = -EPROTO;
 990                 GOTO(out, rc);
 991         }
 992
 993         spin_lock(&imp->imp_lock);
 994
 995         /* All imports are pingable */
 996         imp->imp_pingable = 1;
 997         imp->imp_force_reconnect = 0;
 998         imp->imp_force_verify = 0;
 999
1000         imp->imp_connect_data = *ocd;
1001
1002         CDEBUG(D_HA, "%s: connect to target with instance %u\n",
1003                imp->imp_obd->obd_name, ocd->ocd_instance);
1004         exp = class_conn2export(&imp->imp_dlm_handle);
1005
1006         spin_unlock(&imp->imp_lock);
1007
1008         /* check that server granted subset of flags we asked for. */
1009         if ((ocd->ocd_connect_flags & imp->imp_connect_flags_orig) !=
1010             ocd->ocd_connect_flags) {
1011                 CERROR("%s: Server didn't granted asked subset of flags: "
1012                        "asked="LPX64" grranted="LPX64"\n",
1013                        imp->imp_obd->obd_name,imp->imp_connect_flags_orig,
1014                        ocd->ocd_connect_flags);
1015                 GOTO(out, rc = -EPROTO);
1016         }
1017
1018         if (!(imp->imp_connect_flags_orig & OBD_CONNECT_LIGHTWEIGHT) &&
1019             (imp->imp_connect_flags_orig & OBD_CONNECT_MDS_MDS) &&
1020             (imp->imp_connect_flags_orig & OBD_CONNECT_FID) &&
1021             (ocd->ocd_connect_flags & OBD_CONNECT_VERSION)) {
1022                 __u32 major = OBD_OCD_VERSION_MAJOR(ocd->ocd_version);
1023                 __u32 minor = OBD_OCD_VERSION_MINOR(ocd->ocd_version);
1024                 __u32 patch = OBD_OCD_VERSION_PATCH(ocd->ocd_version);
1025
1026                 /* We do not support the MDT-MDT interoperations with
1027                  * different version MDT because of protocol changes. */
1028                 if (unlikely(major != LUSTRE_MAJOR ||
1029                              minor != LUSTRE_MINOR ||
1030                              abs(patch - LUSTRE_PATCH) > 3)) {
1031                         LCONSOLE_WARN("%s: import %p (%u.%u.%u.%u) tried the "
1032                                       "connection to different version MDT "
1033                                       "(%d.%d.%d.%d) %s\n",
1034                                       imp->imp_obd->obd_name, imp, LUSTRE_MAJOR,
1035                                       LUSTRE_MINOR, LUSTRE_PATCH, LUSTRE_FIX,
1036                                       major, minor, patch,
1037                                       OBD_OCD_VERSION_FIX(ocd->ocd_version),
1038                                       imp->imp_connection->c_remote_uuid.uuid);
1039
1040                         GOTO(out, rc = -EPROTO);
1041                 }
1042         }
1043
1044         if (!exp) {
1045                 /* This could happen if export is cleaned during the
1046                    connect attempt */
1047                 CERROR("%s: missing export after connect\n",
1048                        imp->imp_obd->obd_name);
1049                 GOTO(out, rc = -ENODEV);
1050         }
1051         old_connect_flags = exp_connect_flags(exp);
1052         exp->exp_connect_data = *ocd;
1053         imp->imp_obd->obd_self_export->exp_connect_data = *ocd;
1054
1055         /* The net statistics after (re-)connect is not valid anymore,
1056          * because may reflect other routing, etc. */
1057         at_init(&imp->imp_at.iat_net_latency, 0, 0);
1058         ptlrpc_at_adj_net_latency(request,
1059                         lustre_msg_get_service_time(request->rq_repmsg));
1060
1061         /* Import flags should be updated before waking import at FULL state */
1062         rc = ptlrpc_connect_set_flags(imp, ocd, old_connect_flags, exp,
1063                                  aa->pcaa_initial_connect);
1064         class_export_put(exp);
1065         if (rc != 0)
1066                 GOTO(out, rc);
1067
1068         obd_import_event(imp->imp_obd, imp, IMP_EVENT_OCD);
1069
1070         if (aa->pcaa_initial_connect) {
1071                 spin_lock(&imp->imp_lock);
1072                 if (msg_flags & MSG_CONNECT_REPLAYABLE) {
1073                         imp->imp_replayable = 1;
1074                         spin_unlock(&imp->imp_lock);
1075                         CDEBUG(D_HA, "connected to replayable target: %s\n",
1076                                obd2cli_tgt(imp->imp_obd));
1077                 } else {
1078                         imp->imp_replayable = 0;
1079                         spin_unlock(&imp->imp_lock);
1080                 }
1081
1082                 /* if applies, adjust the imp->imp_msg_magic here
1083                  * according to reply flags */
1084
1085                 imp->imp_remote_handle =
1086                                 *lustre_msg_get_handle(request->rq_repmsg);
1087
1088                 /* Initial connects are allowed for clients with non-random
1089                  * uuids when servers are in recovery.  Simply signal the
1090                  * servers replay is complete and wait in REPLAY_WAIT. */
1091                 if (msg_flags & MSG_CONNECT_RECOVERING) {
1092                         CDEBUG(D_HA, "connect to %s during recovery\n",
1093                                obd2cli_tgt(imp->imp_obd));
1094                         IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY_LOCKS);
1095                 } else {
1096                         IMPORT_SET_STATE(imp, LUSTRE_IMP_FULL);
1097                         ptlrpc_activate_import(imp);
1098                 }
1099
1100                 GOTO(finish, rc = 0);
1101         }
1102
1103         /* Determine what recovery state to move the import to. */
1104         if (MSG_CONNECT_RECONNECT & msg_flags) {
1105                 memset(&old_hdl, 0, sizeof(old_hdl));
1106                 if (!memcmp(&old_hdl, lustre_msg_get_handle(request->rq_repmsg),
1107                             sizeof (old_hdl))) {
1108                         LCONSOLE_WARN("Reconnect to %s (at @%s) failed due "
1109                                       "bad handle "LPX64"\n",
1110                                       obd2cli_tgt(imp->imp_obd),
1111                                       imp->imp_connection->c_remote_uuid.uuid,
1112                                       imp->imp_dlm_handle.cookie);
1113                         GOTO(out, rc = -ENOTCONN);
1114                 }
1115
1116                 if (memcmp(&imp->imp_remote_handle,
1117                            lustre_msg_get_handle(request->rq_repmsg),
1118                            sizeof(imp->imp_remote_handle))) {
1119                         int level = msg_flags & MSG_CONNECT_RECOVERING ?
1120                                 D_HA : D_WARNING;
1121
1122                         /* Bug 16611/14775: if server handle have changed,
1123                          * that means some sort of disconnection happened.
1124                          * If the server is not in recovery, that also means it
1125                          * already erased all of our state because of previous
1126                          * eviction. If it is in recovery - we are safe to
1127                          * participate since we can reestablish all of our state
1128                          * with server again */
1129                         if ((MSG_CONNECT_RECOVERING & msg_flags)) {
1130                                 CDEBUG(level,"%s@%s changed server handle from "
1131                                        LPX64" to "LPX64
1132                                        " but is still in recovery\n",
1133                                        obd2cli_tgt(imp->imp_obd),
1134                                        imp->imp_connection->c_remote_uuid.uuid,
1135                                        imp->imp_remote_handle.cookie,
1136                                        lustre_msg_get_handle(
1137                                        request->rq_repmsg)->cookie);
1138                         } else {
1139                                 LCONSOLE_WARN("Evicted from %s (at %s) "
1140                                               "after server handle changed from "
1141                                               LPX64" to "LPX64"\n",
1142                                               obd2cli_tgt(imp->imp_obd),
1143                                               imp->imp_connection-> \
1144                                               c_remote_uuid.uuid,
1145                                               imp->imp_remote_handle.cookie,
1146                                               lustre_msg_get_handle(
1147                                               request->rq_repmsg)->cookie);
1148                         }
1149
1150
1151                         imp->imp_remote_handle =
1152                                      *lustre_msg_get_handle(request->rq_repmsg);
1153
1154                         if (!(MSG_CONNECT_RECOVERING & msg_flags)) {
1155                                 IMPORT_SET_STATE(imp, LUSTRE_IMP_EVICTED);
1156                                 GOTO(finish, rc = 0);
1157                         }
1158
1159                 } else {
1160                         CDEBUG(D_HA, "reconnected to %s@%s after partition\n",
1161                                obd2cli_tgt(imp->imp_obd),
1162                                imp->imp_connection->c_remote_uuid.uuid);
1163                 }
1164
1165                 if (imp->imp_invalid) {
1166                         CDEBUG(D_HA, "%s: reconnected but import is invalid; "
1167                                "marking evicted\n", imp->imp_obd->obd_name);
1168                         IMPORT_SET_STATE(imp, LUSTRE_IMP_EVICTED);
1169                 } else if (MSG_CONNECT_RECOVERING & msg_flags) {
1170                         CDEBUG(D_HA, "%s: reconnected to %s during replay\n",
1171                                imp->imp_obd->obd_name,
1172                                obd2cli_tgt(imp->imp_obd));
1173
1174                         spin_lock(&imp->imp_lock);
1175                         imp->imp_resend_replay = 1;
1176                         spin_unlock(&imp->imp_lock);
1177
1178                         IMPORT_SET_STATE(imp, imp->imp_replay_state);
1179                 } else {
1180                         IMPORT_SET_STATE(imp, LUSTRE_IMP_RECOVER);
1181                 }
1182         } else if ((MSG_CONNECT_RECOVERING & msg_flags) && !imp->imp_invalid) {
1183                 LASSERT(imp->imp_replayable);
1184                 imp->imp_remote_handle =
1185                                 *lustre_msg_get_handle(request->rq_repmsg);
1186                 imp->imp_last_replay_transno = 0;
1187                 IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY);
1188         } else {
1189                 DEBUG_REQ(D_HA, request, "%s: evicting (reconnect/recover flags"
1190                           " not set: %x)", imp->imp_obd->obd_name, msg_flags);
1191                 imp->imp_remote_handle =
1192                                 *lustre_msg_get_handle(request->rq_repmsg);
1193                 IMPORT_SET_STATE(imp, LUSTRE_IMP_EVICTED);
1194         }
1195
1196         /* Sanity checks for a reconnected import. */
1197         if (!(imp->imp_replayable) != !(msg_flags & MSG_CONNECT_REPLAYABLE)) {
1198                 CERROR("imp_replayable flag does not match server "
1199                        "after reconnect. We should LBUG right here.\n");
1200         }
1201
1202         if (lustre_msg_get_last_committed(request->rq_repmsg) > 0 &&
1203             lustre_msg_get_last_committed(request->rq_repmsg) <
1204             aa->pcaa_peer_committed) {
1205                 CERROR("%s went back in time (transno "LPD64
1206                        " was previously committed, server now claims "LPD64
1207                        ")!  See https://bugzilla.lustre.org/show_bug.cgi?"
1208                        "id=9646\n",
1209                        obd2cli_tgt(imp->imp_obd), aa->pcaa_peer_committed,
1210                        lustre_msg_get_last_committed(request->rq_repmsg));
1211         }
1212
1213 finish:
1214         rc = ptlrpc_import_recovery_state_machine(imp);
1215         if (rc == -ENOTCONN) {
1216                 CDEBUG(D_HA, "evicted/aborted by %s@%s during recovery;"
1217                        "invalidating and reconnecting\n",
1218                        obd2cli_tgt(imp->imp_obd),
1219                        imp->imp_connection->c_remote_uuid.uuid);
1220                 ptlrpc_connect_import(imp);
1221                 imp->imp_connect_tried = 1;
1222                 RETURN(0);
1223         }
1224
1225 out:
1226         imp->imp_connect_tried = 1;
1227
1228         if (rc != 0) {
1229                 IMPORT_SET_STATE(imp, LUSTRE_IMP_DISCON);
1230                 if (rc == -EACCES) {
1231                         /*
1232                          * Give up trying to reconnect
1233                          * EACCES means client has no permission for connection
1234                          */
1235                         imp->imp_obd->obd_no_recov = 1;
1236                         ptlrpc_deactivate_import(imp);
1237                 }
1238
1239                 if (rc == -EPROTO) {
1240                         struct obd_connect_data *ocd;
1241
1242                         /* reply message might not be ready */
1243                         if (request->rq_repmsg == NULL)
1244                                 RETURN(-EPROTO);
1245
1246                         ocd = req_capsule_server_get(&request->rq_pill,
1247                                                      &RMF_CONNECT_DATA);
1248                         if (ocd &&
1249                             (ocd->ocd_connect_flags & OBD_CONNECT_VERSION) &&
1250                             (ocd->ocd_version != LUSTRE_VERSION_CODE)) {
1251                            /* Actually servers are only supposed to refuse
1252                               connection from liblustre clients, so we should
1253                               never see this from VFS context */
1254                                 LCONSOLE_ERROR_MSG(0x16a, "Server %s version "
1255                                         "(%d.%d.%d.%d)"
1256                                         " refused connection from this client "
1257                                         "with an incompatible version (%s).  "
1258                                         "Client must be recompiled\n",
1259                                         obd2cli_tgt(imp->imp_obd),
1260                                         OBD_OCD_VERSION_MAJOR(ocd->ocd_version),
1261                                         OBD_OCD_VERSION_MINOR(ocd->ocd_version),
1262                                         OBD_OCD_VERSION_PATCH(ocd->ocd_version),
1263                                         OBD_OCD_VERSION_FIX(ocd->ocd_version),
1264                                         LUSTRE_VERSION_STRING);
1265                                 ptlrpc_deactivate_import(imp);
1266                                 IMPORT_SET_STATE(imp, LUSTRE_IMP_CLOSED);
1267                         }
1268                         RETURN(-EPROTO);
1269                 }
1270
1271                 ptlrpc_maybe_ping_import_soon(imp);
1272
1273                 CDEBUG(D_HA, "recovery of %s on %s failed (%d)\n",
1274                        obd2cli_tgt(imp->imp_obd),
1275                        (char *)imp->imp_connection->c_remote_uuid.uuid, rc);
1276         }
1277
1278         wake_up_all(&imp->imp_recovery_waitq);
1279         RETURN(rc);
1280 }
1281
1282 /**
1283  * interpret callback for "completed replay" RPCs.
1284  * \see signal_completed_replay
1285  */
1286 static int completed_replay_interpret(const struct lu_env *env,
1287                                       struct ptlrpc_request *req,
1288                                       void * data, int rc)
1289 {
1290         ENTRY;
1291         atomic_dec(&req->rq_import->imp_replay_inflight);
1292         if (req->rq_status == 0 &&
1293             !req->rq_import->imp_vbr_failed) {
1294                 ptlrpc_import_recovery_state_machine(req->rq_import);
1295         } else {
1296                 if (req->rq_import->imp_vbr_failed) {
1297                         CDEBUG(D_WARNING,
1298                                "%s: version recovery fails, reconnecting\n",
1299                                req->rq_import->imp_obd->obd_name);
1300                 } else {
1301                         CDEBUG(D_HA, "%s: LAST_REPLAY message error: %d, "
1302                                      "reconnecting\n",
1303                                req->rq_import->imp_obd->obd_name,
1304                                req->rq_status);
1305                 }
1306                 ptlrpc_connect_import(req->rq_import);
1307         }
1308
1309         RETURN(0);
1310 }
1311
1312 /**
1313  * Let server know that we have no requests to replay anymore.
1314  * Achieved by just sending a PING request
1315  */
1316 static int signal_completed_replay(struct obd_import *imp)
1317 {
1318         struct ptlrpc_request *req;
1319         ENTRY;
1320
1321         if (unlikely(OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_FINISH_REPLAY)))
1322                 RETURN(0);
1323
1324         LASSERT(atomic_read(&imp->imp_replay_inflight) == 0);
1325         atomic_inc(&imp->imp_replay_inflight);
1326
1327         req = ptlrpc_request_alloc_pack(imp, &RQF_OBD_PING, LUSTRE_OBD_VERSION,
1328                                         OBD_PING);
1329         if (req == NULL) {
1330                 atomic_dec(&imp->imp_replay_inflight);
1331                 RETURN(-ENOMEM);
1332         }
1333
1334         ptlrpc_request_set_replen(req);
1335         req->rq_send_state = LUSTRE_IMP_REPLAY_WAIT;
1336         lustre_msg_add_flags(req->rq_reqmsg,
1337                              MSG_LOCK_REPLAY_DONE | MSG_REQ_REPLAY_DONE);
1338         if (AT_OFF)
1339                 req->rq_timeout *= 3;
1340         req->rq_interpret_reply = completed_replay_interpret;
1341
1342         ptlrpcd_add_req(req, PDL_POLICY_ROUND, -1);
1343         RETURN(0);
1344 }
1345
1346 /**
1347  * In kernel code all import invalidation happens in its own
1348  * separate thread, so that whatever application happened to encounter
1349  * a problem could still be killed or otherwise continue
1350  */
1351 static int ptlrpc_invalidate_import_thread(void *data)
1352 {
1353         struct obd_import *imp = data;
1354
1355         ENTRY;
1356
1357         unshare_fs_struct();
1358
1359         CDEBUG(D_HA, "thread invalidate import %s to %s@%s\n",
1360                imp->imp_obd->obd_name, obd2cli_tgt(imp->imp_obd),
1361                imp->imp_connection->c_remote_uuid.uuid);
1362
1363         ptlrpc_invalidate_import(imp);
1364
1365         if (obd_dump_on_eviction) {
1366                 CERROR("dump the log upon eviction\n");
1367                 libcfs_debug_dumplog();
1368         }
1369
1370         IMPORT_SET_STATE(imp, LUSTRE_IMP_RECOVER);
1371         ptlrpc_import_recovery_state_machine(imp);
1372
1373         class_import_put(imp);
1374         RETURN(0);
1375 }
1376
1377 /**
1378  * This is the state machine for client-side recovery on import.
1379  *
1380  * Typicaly we have two possibly paths. If we came to server and it is not
1381  * in recovery, we just enter IMP_EVICTED state, invalidate our import
1382  * state and reconnect from scratch.
1383  * If we came to server that is in recovery, we enter IMP_REPLAY import state.
1384  * We go through our list of requests to replay and send them to server one by
1385  * one.
1386  * After sending all request from the list we change import state to
1387  * IMP_REPLAY_LOCKS and re-request all the locks we believe we have from server
1388  * and also all the locks we don't yet have and wait for server to grant us.
1389  * After that we send a special "replay completed" request and change import
1390  * state to IMP_REPLAY_WAIT.
1391  * Upon receiving reply to that "replay completed" RPC we enter IMP_RECOVER
1392  * state and resend all requests from sending list.
1393  * After that we promote import to FULL state and send all delayed requests
1394  * and import is fully operational after that.
1395  *
1396  */
1397 int ptlrpc_import_recovery_state_machine(struct obd_import *imp)
1398 {
1399         int rc = 0;
1400         int inflight;
1401         char *target_start;
1402         int target_len;
1403
1404         ENTRY;
1405         if (imp->imp_state == LUSTRE_IMP_EVICTED) {
1406                 deuuidify(obd2cli_tgt(imp->imp_obd), NULL,
1407                           &target_start, &target_len);
1408                 /* Don't care about MGC eviction */
1409                 if (strcmp(imp->imp_obd->obd_type->typ_name,
1410                            LUSTRE_MGC_NAME) != 0) {
1411                         LCONSOLE_ERROR_MSG(0x167, "%s: This client was evicted "
1412                                            "by %.*s; in progress operations "
1413                                            "using this service will fail.\n",
1414                                            imp->imp_obd->obd_name, target_len,
1415                                            target_start);
1416                 }
1417                 CDEBUG(D_HA, "evicted from %s@%s; invalidating\n",
1418                        obd2cli_tgt(imp->imp_obd),
1419                        imp->imp_connection->c_remote_uuid.uuid);
1420                 /* reset vbr_failed flag upon eviction */
1421                 spin_lock(&imp->imp_lock);
1422                 imp->imp_vbr_failed = 0;
1423                 spin_unlock(&imp->imp_lock);
1424
1425                 {
1426                 struct task_struct *task;
1427                 /* bug 17802:  XXX client_disconnect_export vs connect request
1428                  * race. if client is evicted at this time then we start
1429                  * invalidate thread without reference to import and import can
1430                  * be freed at same time. */
1431                 class_import_get(imp);
1432                 task = kthread_run(ptlrpc_invalidate_import_thread, imp,
1433                                      "ll_imp_inval");
1434                 if (IS_ERR(task)) {
1435                         class_import_put(imp);
1436                         CERROR("error starting invalidate thread: %d\n", rc);
1437                         rc = PTR_ERR(task);
1438                 } else {
1439                         rc = 0;
1440                 }
1441                 RETURN(rc);
1442                 }
1443         }
1444
1445         if (imp->imp_state == LUSTRE_IMP_REPLAY) {
1446                 CDEBUG(D_HA, "replay requested by %s\n",
1447                        obd2cli_tgt(imp->imp_obd));
1448                 rc = ptlrpc_replay_next(imp, &inflight);
1449                 if (inflight == 0 &&
1450                     atomic_read(&imp->imp_replay_inflight) == 0) {
1451                         IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY_LOCKS);
1452                         rc = ldlm_replay_locks(imp);
1453                         if (rc)
1454                                 GOTO(out, rc);
1455                 }
1456                 rc = 0;
1457         }
1458
1459         if (imp->imp_state == LUSTRE_IMP_REPLAY_LOCKS) {
1460                 if (atomic_read(&imp->imp_replay_inflight) == 0) {
1461                         IMPORT_SET_STATE(imp, LUSTRE_IMP_REPLAY_WAIT);
1462                         rc = signal_completed_replay(imp);
1463                         if (rc)
1464                                 GOTO(out, rc);
1465                 }
1466         }
1467
1468         if (imp->imp_state == LUSTRE_IMP_REPLAY_WAIT) {
1469                 if (atomic_read(&imp->imp_replay_inflight) == 0) {
1470                         IMPORT_SET_STATE(imp, LUSTRE_IMP_RECOVER);
1471                 }
1472         }
1473
1474         if (imp->imp_state == LUSTRE_IMP_RECOVER) {
1475                 CDEBUG(D_HA, "reconnected to %s@%s\n",
1476                        obd2cli_tgt(imp->imp_obd),
1477                        imp->imp_connection->c_remote_uuid.uuid);
1478
1479                 rc = ptlrpc_resend(imp);
1480                 if (rc)
1481                         GOTO(out, rc);
1482                 IMPORT_SET_STATE(imp, LUSTRE_IMP_FULL);
1483                 ptlrpc_activate_import(imp);
1484
1485                 deuuidify(obd2cli_tgt(imp->imp_obd), NULL,
1486                           &target_start, &target_len);
1487                 LCONSOLE_INFO("%s: Connection restored to %.*s (at %s)\n",
1488                               imp->imp_obd->obd_name,
1489                               target_len, target_start,
1490                               libcfs_nid2str(imp->imp_connection->c_peer.nid));
1491         }
1492
1493         if (imp->imp_state == LUSTRE_IMP_FULL) {
1494                 wake_up_all(&imp->imp_recovery_waitq);
1495                 ptlrpc_wake_delayed(imp);
1496         }
1497
1498 out:
1499         RETURN(rc);
1500 }
1501
1502 int ptlrpc_disconnect_import(struct obd_import *imp, int noclose)
1503 {
1504         struct ptlrpc_request *req;
1505         int rq_opc, rc = 0;
1506         ENTRY;
1507
1508         if (imp->imp_obd->obd_force)
1509                 GOTO(set_state, rc);
1510
1511         switch (imp->imp_connect_op) {
1512         case OST_CONNECT:
1513                 rq_opc = OST_DISCONNECT;
1514                 break;
1515         case MDS_CONNECT:
1516                 rq_opc = MDS_DISCONNECT;
1517                 break;
1518         case MGS_CONNECT:
1519                 rq_opc = MGS_DISCONNECT;
1520                 break;
1521         default:
1522                 rc = -EINVAL;
1523                 CERROR("%s: don't know how to disconnect from %s "
1524                        "(connect_op %d): rc = %d\n",
1525                        imp->imp_obd->obd_name, obd2cli_tgt(imp->imp_obd),
1526                        imp->imp_connect_op, rc);
1527                 RETURN(rc);
1528         }
1529
1530         if (ptlrpc_import_in_recovery(imp)) {
1531                 struct l_wait_info lwi;
1532                 cfs_duration_t timeout;
1533
1534                 if (AT_OFF) {
1535                         if (imp->imp_server_timeout)
1536                                 timeout = cfs_time_seconds(obd_timeout / 2);
1537                         else
1538                                 timeout = cfs_time_seconds(obd_timeout);
1539                 } else {
1540                         int idx = import_at_get_index(imp,
1541                                 imp->imp_client->cli_request_portal);
1542                         timeout = cfs_time_seconds(
1543                                 at_get(&imp->imp_at.iat_service_estimate[idx]));
1544                 }
1545
1546                 lwi = LWI_TIMEOUT_INTR(cfs_timeout_cap(timeout),
1547                                        back_to_sleep, LWI_ON_SIGNAL_NOOP, NULL);
1548                 rc = l_wait_event(imp->imp_recovery_waitq,
1549                                   !ptlrpc_import_in_recovery(imp), &lwi);
1550
1551         }
1552
1553         spin_lock(&imp->imp_lock);
1554         if (imp->imp_state != LUSTRE_IMP_FULL)
1555                 GOTO(out, rc);
1556         spin_unlock(&imp->imp_lock);
1557
1558         req = ptlrpc_request_alloc_pack(imp, &RQF_MDS_DISCONNECT,
1559                                         LUSTRE_OBD_VERSION, rq_opc);
1560         if (req) {
1561                 /* We are disconnecting, do not retry a failed DISCONNECT rpc if
1562                  * it fails.  We can get through the above with a down server
1563                  * if the client doesn't know the server is gone yet. */
1564                 req->rq_no_resend = 1;
1565
1566                 /* We want client umounts to happen quickly, no matter the
1567                    server state... */
1568                 req->rq_timeout = min_t(int, req->rq_timeout,
1569                                         INITIAL_CONNECT_TIMEOUT);
1570
1571                 IMPORT_SET_STATE(imp, LUSTRE_IMP_CONNECTING);
1572                 req->rq_send_state =  LUSTRE_IMP_CONNECTING;
1573                 ptlrpc_request_set_replen(req);
1574                 rc = ptlrpc_queue_wait(req);
1575                 ptlrpc_req_finished(req);
1576         }
1577
1578 set_state:
1579         spin_lock(&imp->imp_lock);
1580 out:
1581         if (noclose)
1582                 IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_DISCON);
1583         else
1584                 IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_CLOSED);
1585         memset(&imp->imp_remote_handle, 0, sizeof(imp->imp_remote_handle));
1586         spin_unlock(&imp->imp_lock);
1587
1588         if (rc == -ETIMEDOUT || rc == -ENOTCONN || rc == -ESHUTDOWN)
1589                 rc = 0;
1590         RETURN(rc);
1591 }
1592 EXPORT_SYMBOL(ptlrpc_disconnect_import);
1593
1594 void ptlrpc_cleanup_imp(struct obd_import *imp)
1595 {
1596         ENTRY;
1597
1598         spin_lock(&imp->imp_lock);
1599         IMPORT_SET_STATE_NOLOCK(imp, LUSTRE_IMP_CLOSED);
1600         imp->imp_generation++;
1601         spin_unlock(&imp->imp_lock);
1602         ptlrpc_abort_inflight(imp);
1603
1604         EXIT;
1605 }
1606
1607 /* Adaptive Timeout utils */
1608 extern unsigned int at_min, at_max, at_history;
1609
1610 /* Update at_current with the specified value (bounded by at_min and at_max),
1611  * as well as the AT history "bins".
1612  *  - Bin into timeslices using AT_BINS bins.
1613  *  - This gives us a max of the last at_history seconds without the storage,
1614  *    but still smoothing out a return to normalcy from a slow response.
1615  *  - (E.g. remember the maximum latency in each minute of the last 4 minutes.)
1616  */
1617 int at_measured(struct adaptive_timeout *at, unsigned int val)
1618 {
1619         unsigned int old = at->at_current;
1620         time_t now = cfs_time_current_sec();
1621         time_t binlimit = max_t(time_t, at_history / AT_BINS, 1);
1622
1623         LASSERT(at);
1624         CDEBUG(D_OTHER, "add %u to %p time=%lu v=%u (%u %u %u %u)\n",
1625                val, at, now - at->at_binstart, at->at_current,
1626                at->at_hist[0], at->at_hist[1], at->at_hist[2], at->at_hist[3]);
1627
1628         if (val == 0)
1629                 /* 0's don't count, because we never want our timeout to
1630                    drop to 0, and because 0 could mean an error */
1631                 return 0;
1632
1633         spin_lock(&at->at_lock);
1634
1635         if (unlikely(at->at_binstart == 0)) {
1636                 /* Special case to remove default from history */
1637                 at->at_current = val;
1638                 at->at_worst_ever = val;
1639                 at->at_worst_time = now;
1640                 at->at_hist[0] = val;
1641                 at->at_binstart = now;
1642         } else if (now - at->at_binstart < binlimit ) {
1643                 /* in bin 0 */
1644                 at->at_hist[0] = max(val, at->at_hist[0]);
1645                 at->at_current = max(val, at->at_current);
1646         } else {
1647                 int i, shift;
1648                 unsigned int maxv = val;
1649                 /* move bins over */
1650                 shift = (now - at->at_binstart) / binlimit;
1651                 LASSERT(shift > 0);
1652                 for(i = AT_BINS - 1; i >= 0; i--) {
1653                         if (i >= shift) {
1654                                 at->at_hist[i] = at->at_hist[i - shift];
1655                                 maxv = max(maxv, at->at_hist[i]);
1656                         } else {
1657                                 at->at_hist[i] = 0;
1658                         }
1659                 }
1660                 at->at_hist[0] = val;
1661                 at->at_current = maxv;
1662                 at->at_binstart += shift * binlimit;
1663         }
1664
1665         if (at->at_current > at->at_worst_ever) {
1666                 at->at_worst_ever = at->at_current;
1667                 at->at_worst_time = now;
1668         }
1669
1670         if (at->at_flags & AT_FLG_NOHIST)
1671                 /* Only keep last reported val; keeping the rest of the history
1672                    for proc only */
1673                 at->at_current = val;
1674
1675         if (at_max > 0)
1676                 at->at_current =  min(at->at_current, at_max);
1677         at->at_current =  max(at->at_current, at_min);
1678
1679         if (at->at_current != old)
1680                 CDEBUG(D_OTHER, "AT %p change: old=%u new=%u delta=%d "
1681                        "(val=%u) hist %u %u %u %u\n", at,
1682                        old, at->at_current, at->at_current - old, val,
1683                        at->at_hist[0], at->at_hist[1], at->at_hist[2],
1684                        at->at_hist[3]);
1685
1686         /* if we changed, report the old value */
1687         old = (at->at_current != old) ? old : 0;
1688
1689         spin_unlock(&at->at_lock);
1690         return old;
1691 }
1692
1693 /* Find the imp_at index for a given portal; assign if space available */
1694 int import_at_get_index(struct obd_import *imp, int portal)
1695 {
1696         struct imp_at *at = &imp->imp_at;
1697         int i;
1698
1699         for (i = 0; i < IMP_AT_MAX_PORTALS; i++) {
1700                 if (at->iat_portal[i] == portal)
1701                         return i;
1702                 if (at->iat_portal[i] == 0)
1703                         /* unused */
1704                         break;
1705         }
1706
1707         /* Not found in list, add it under a lock */
1708         spin_lock(&imp->imp_lock);
1709
1710         /* Check unused under lock */
1711         for (; i < IMP_AT_MAX_PORTALS; i++) {
1712                 if (at->iat_portal[i] == portal)
1713                         goto out;
1714                 if (at->iat_portal[i] == 0)
1715                         /* unused */
1716                         break;
1717         }
1718
1719         /* Not enough portals? */
1720         LASSERT(i < IMP_AT_MAX_PORTALS);
1721
1722         at->iat_portal[i] = portal;
1723 out:
1724         spin_unlock(&imp->imp_lock);
1725         return i;
1726 }