lustre/ldlm/ldlm_flock.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2003 Hewlett-Packard Development Company LP.
  24  * Developed under the sponsorship of the US Government under
  25  * Subcontract No. B514193
  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) 2010, 2017, 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
  37 /**
  38  * This file implements POSIX lock type for Lustre.
  39  * Its policy properties are start and end of extent and PID.
  40  *
  41  * These locks are only done through MDS due to POSIX semantics requiring
  42  * e.g. that locks could be only partially released and as such split into
  43  * two parts, and also that two adjacent locks from the same process may be
  44  * merged into a single wider lock.
  45  *
  46  * Lock modes are mapped like this:
  47  * PR and PW for READ and WRITE locks
  48  * NL to request a releasing of a portion of the lock
  49  *
  50  * These flock locks never timeout.
  51  */
  52
  53 #define DEBUG_SUBSYSTEM S_LDLM
  54
  55 #include <linux/list.h>
  56 #include <lustre_dlm.h>
  57 #include <obd_support.h>
  58 #include <obd_class.h>
  59 #include <lustre_lib.h>
  60
  61 #include "ldlm_internal.h"
  62
  63 int ldlm_flock_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
  64                             void *data, int flag);
  65
  66 /**
  67  * list_for_remaining_safe - iterate over the remaining entries in a list
  68  *              and safeguard against removal of a list entry.
  69  * \param pos   the &struct list_head to use as a loop counter. pos MUST
  70  *              have been initialized prior to using it in this macro.
  71  * \param n     another &struct list_head to use as temporary storage
  72  * \param head  the head for your list.
  73  */
  74 #define list_for_remaining_safe(pos, n, head) \
  75         for (n = pos->next; pos != (head); pos = n, n = pos->next)
  76
  77 static inline int
  78 ldlm_same_flock_owner(struct ldlm_lock *lock, struct ldlm_lock *new)
  79 {
  80         return((new->l_policy_data.l_flock.owner ==
  81                 lock->l_policy_data.l_flock.owner) &&
  82                (new->l_export == lock->l_export));
  83 }
  84
  85 static inline int
  86 ldlm_flocks_overlap(struct ldlm_lock *lock, struct ldlm_lock *new)
  87 {
  88         return((new->l_policy_data.l_flock.start <=
  89                 lock->l_policy_data.l_flock.end) &&
  90                (new->l_policy_data.l_flock.end >=
  91                 lock->l_policy_data.l_flock.start));
  92 }
  93
  94 static inline void ldlm_flock_blocking_link(struct ldlm_lock *req,
  95                                             struct ldlm_lock *lock)
  96 {
  97         /* For server only */
  98         if (req->l_export == NULL)
  99                 return;
 100
 101         LASSERT(hlist_unhashed(&req->l_exp_flock_hash));
 102
 103         req->l_policy_data.l_flock.blocking_owner =
 104                 lock->l_policy_data.l_flock.owner;
 105         req->l_policy_data.l_flock.blocking_export =
 106                 lock->l_export;
 107         atomic_set(&req->l_policy_data.l_flock.blocking_refs, 0);
 108
 109         cfs_hash_add(req->l_export->exp_flock_hash,
 110                      &req->l_policy_data.l_flock.owner,
 111                      &req->l_exp_flock_hash);
 112 }
 113
 114 static inline void ldlm_flock_blocking_unlink(struct ldlm_lock *req)
 115 {
 116         /* For server only */
 117         if (req->l_export == NULL)
 118                 return;
 119
 120         check_res_locked(req->l_resource);
 121         if (req->l_export->exp_flock_hash != NULL &&
 122             !hlist_unhashed(&req->l_exp_flock_hash))
 123                 cfs_hash_del(req->l_export->exp_flock_hash,
 124                              &req->l_policy_data.l_flock.owner,
 125                              &req->l_exp_flock_hash);
 126 }
 127
 128 static inline void
 129 ldlm_flock_destroy(struct ldlm_lock *lock, enum ldlm_mode mode, __u64 flags)
 130 {
 131         ENTRY;
 132
 133         LDLM_DEBUG(lock, "ldlm_flock_destroy(mode: %d, flags: %#llx)",
 134                    mode, flags);
 135
 136         /* Safe to not lock here, since it should be empty anyway */
 137         LASSERT(hlist_unhashed(&lock->l_exp_flock_hash));
 138
 139         list_del_init(&lock->l_res_link);
 140         if (flags == LDLM_FL_WAIT_NOREPROC) {
 141                 /* client side - set a flag to prevent sending a CANCEL */
 142                 lock->l_flags |= LDLM_FL_LOCAL_ONLY | LDLM_FL_CBPENDING;
 143
 144                 /* when reaching here, it is under lock_res_and_lock(). Thus,
 145                    need call the nolock version of ldlm_lock_decref_internal*/
 146                 ldlm_lock_decref_internal_nolock(lock, mode);
 147         }
 148
 149         ldlm_lock_destroy_nolock(lock);
 150         EXIT;
 151 }
 152
 153 /**
 154  * POSIX locks deadlock detection code.
 155  *
 156  * Given a new lock \a req and an existing lock \a bl_lock it conflicts
 157  * with, we need to iterate through all blocked POSIX locks for this
 158  * export and see if there is a deadlock condition arising. (i.e. when
 159  * one client holds a lock on something and want a lock on something
 160  * else and at the same time another client has the opposite situation).
 161  */
 162
 163 struct ldlm_flock_lookup_cb_data {
 164         __u64 *bl_owner;
 165         struct ldlm_lock *lock;
 166         struct obd_export *exp;
 167 };
 168
 169 static int ldlm_flock_lookup_cb(struct cfs_hash *hs, struct cfs_hash_bd *bd,
 170                                 struct hlist_node *hnode, void *data)
 171 {
 172         struct ldlm_flock_lookup_cb_data *cb_data = data;
 173         struct obd_export *exp = cfs_hash_object(hs, hnode);
 174         struct ldlm_lock *lock;
 175
 176         lock = cfs_hash_lookup(exp->exp_flock_hash, cb_data->bl_owner);
 177         if (lock == NULL)
 178                 return 0;
 179
 180         /* Stop on first found lock. Same process can't sleep twice */
 181         cb_data->lock = lock;
 182         cb_data->exp = class_export_get(exp);
 183
 184         return 1;
 185 }
 186
 187 static int
 188 ldlm_flock_deadlock(struct ldlm_lock *req, struct ldlm_lock *bl_lock)
 189 {
 190         struct obd_export *req_exp = req->l_export;
 191         struct obd_export *bl_exp = bl_lock->l_export;
 192         __u64 req_owner = req->l_policy_data.l_flock.owner;
 193         __u64 bl_owner = bl_lock->l_policy_data.l_flock.owner;
 194
 195         /* For server only */
 196         if (req_exp == NULL)
 197                 return 0;
 198
 199         class_export_get(bl_exp);
 200         while (1) {
 201                 struct ldlm_flock_lookup_cb_data cb_data = {
 202                                         .bl_owner = &bl_owner,
 203                                         .lock = NULL,
 204                                         .exp = NULL };
 205                 struct obd_export *bl_exp_new;
 206                 struct ldlm_lock *lock = NULL;
 207                 struct ldlm_flock *flock;
 208
 209                 if (bl_exp->exp_flock_hash != NULL) {
 210                         cfs_hash_for_each_key(bl_exp->exp_obd->obd_nid_hash,
 211                                 &bl_exp->exp_connection->c_peer.nid,
 212                                 ldlm_flock_lookup_cb, &cb_data);
 213                         lock = cb_data.lock;
 214                 }
 215                 if (lock == NULL)
 216                         break;
 217
 218                 class_export_put(bl_exp);
 219                 bl_exp = cb_data.exp;
 220
 221                 LASSERT(req != lock);
 222                 flock = &lock->l_policy_data.l_flock;
 223                 LASSERT(flock->owner == bl_owner);
 224                 bl_owner = flock->blocking_owner;
 225                 bl_exp_new = class_export_get(flock->blocking_export);
 226                 class_export_put(bl_exp);
 227
 228                 cfs_hash_put(bl_exp->exp_flock_hash, &lock->l_exp_flock_hash);
 229                 bl_exp = bl_exp_new;
 230
 231                 if (bl_exp->exp_failed)
 232                         break;
 233
 234                 if (bl_owner == req_owner &&
 235                     (bl_exp->exp_connection->c_peer.nid ==
 236                      req_exp->exp_connection->c_peer.nid)) {
 237                         class_export_put(bl_exp);
 238                         return 1;
 239                 }
 240         }
 241         class_export_put(bl_exp);
 242
 243         return 0;
 244 }
 245
 246 static void ldlm_flock_cancel_on_deadlock(struct ldlm_lock *lock,
 247                                           struct list_head *work_list)
 248 {
 249         CDEBUG(D_INFO, "reprocess deadlock req=%p\n", lock);
 250
 251         if ((exp_connect_flags(lock->l_export) &
 252                                 OBD_CONNECT_FLOCK_DEAD) == 0) {
 253                 CERROR("deadlock found, but client doesn't "
 254                                 "support flock canceliation\n");
 255         } else {
 256                 LASSERT(lock->l_completion_ast);
 257                 LASSERT(!ldlm_is_ast_sent(lock));
 258                 lock->l_flags |= LDLM_FL_AST_SENT | LDLM_FL_CANCEL_ON_BLOCK |
 259                         LDLM_FL_FLOCK_DEADLOCK;
 260                 ldlm_flock_blocking_unlink(lock);
 261                 ldlm_resource_unlink_lock(lock);
 262                 ldlm_add_ast_work_item(lock, NULL, work_list);
 263         }
 264 }
 265
 266 /**
 267  * Process a granting attempt for flock lock.
 268  * Must be called under ns lock held.
 269  *
 270  * This function looks for any conflicts for \a lock in the granted or
 271  * waiting queues. The lock is granted if no conflicts are found in
 272  * either queue.
 273  */
 274 int
 275 ldlm_process_flock_lock(struct ldlm_lock *req, __u64 *flags,
 276                         enum ldlm_process_intention intention,
 277                         enum ldlm_error *err, struct list_head *work_list)
 278 {
 279         struct ldlm_resource *res = req->l_resource;
 280         struct ldlm_namespace *ns = ldlm_res_to_ns(res);
 281         struct list_head *tmp;
 282         struct list_head *ownlocks = NULL;
 283         struct ldlm_lock *lock = NULL;
 284         struct ldlm_lock *new = req;
 285         struct ldlm_lock *new2 = NULL;
 286         enum ldlm_mode mode = req->l_req_mode;
 287         int local = ns_is_client(ns);
 288         int added = (mode == LCK_NL);
 289         int overlaps = 0;
 290         int splitted = 0;
 291         const struct ldlm_callback_suite null_cbs = { NULL };
 292         struct list_head *grant_work = intention == LDLM_PROCESS_ENQUEUE ?
 293                                                         NULL : work_list;
 294         ENTRY;
 295
 296         CDEBUG(D_DLMTRACE, "flags %#llx owner %llu pid %u mode %u start "
 297                "%llu end %llu\n", *flags,
 298                new->l_policy_data.l_flock.owner,
 299                new->l_policy_data.l_flock.pid, mode,
 300                req->l_policy_data.l_flock.start,
 301                req->l_policy_data.l_flock.end);
 302
 303         *err = ELDLM_OK;
 304
 305         if (local) {
 306                 /* No blocking ASTs are sent to the clients for
 307                  * Posix file & record locks */
 308                 req->l_blocking_ast = NULL;
 309         } else {
 310                 /* Called on the server for lock cancels. */
 311                 req->l_blocking_ast = ldlm_flock_blocking_ast;
 312         }
 313
 314 reprocess:
 315         if ((*flags == LDLM_FL_WAIT_NOREPROC) || (mode == LCK_NL)) {
 316                 /* This loop determines where this processes locks start
 317                  * in the resource lr_granted list. */
 318                 list_for_each(tmp, &res->lr_granted) {
 319                         lock = list_entry(tmp, struct ldlm_lock,
 320                                               l_res_link);
 321                         if (ldlm_same_flock_owner(lock, req)) {
 322                                 ownlocks = tmp;
 323                                 break;
 324                         }
 325                 }
 326         } else {
 327                 int reprocess_failed = 0;
 328                 lockmode_verify(mode);
 329
 330                 /* This loop determines if there are existing locks
 331                  * that conflict with the new lock request. */
 332                 list_for_each(tmp, &res->lr_granted) {
 333                         lock = list_entry(tmp, struct ldlm_lock,
 334                                               l_res_link);
 335
 336                         if (ldlm_same_flock_owner(lock, req)) {
 337                                 if (!ownlocks)
 338                                         ownlocks = tmp;
 339                                 continue;
 340                         }
 341
 342                         /* locks are compatible, overlap doesn't matter */
 343                         if (lockmode_compat(lock->l_granted_mode, mode))
 344                                 continue;
 345
 346                         if (!ldlm_flocks_overlap(lock, req))
 347                                 continue;
 348
 349                         if (intention != LDLM_PROCESS_ENQUEUE) {
 350                                 reprocess_failed = 1;
 351                                 if (ldlm_flock_deadlock(req, lock)) {
 352                                         ldlm_flock_cancel_on_deadlock(req,
 353                                                         grant_work);
 354                                         RETURN(LDLM_ITER_CONTINUE);
 355                                 }
 356                                 continue;
 357                         }
 358
 359                         if (*flags & LDLM_FL_BLOCK_NOWAIT) {
 360                                 ldlm_flock_destroy(req, mode, *flags);
 361                                 *err = -EAGAIN;
 362                                 RETURN(LDLM_ITER_STOP);
 363                         }
 364
 365                         if (*flags & LDLM_FL_TEST_LOCK) {
 366                                 ldlm_flock_destroy(req, mode, *flags);
 367                                 req->l_req_mode = lock->l_granted_mode;
 368                                 req->l_policy_data.l_flock.pid =
 369                                         lock->l_policy_data.l_flock.pid;
 370                                 req->l_policy_data.l_flock.start =
 371                                         lock->l_policy_data.l_flock.start;
 372                                 req->l_policy_data.l_flock.end =
 373                                         lock->l_policy_data.l_flock.end;
 374                                 *flags |= LDLM_FL_LOCK_CHANGED;
 375                                 RETURN(LDLM_ITER_STOP);
 376                         }
 377
 378                         /* add lock to blocking list before deadlock
 379                          * check to prevent race */
 380                         ldlm_flock_blocking_link(req, lock);
 381
 382                         if (ldlm_flock_deadlock(req, lock)) {
 383                                 ldlm_flock_blocking_unlink(req);
 384                                 ldlm_flock_destroy(req, mode, *flags);
 385                                 *err = -EDEADLK;
 386                                 RETURN(LDLM_ITER_STOP);
 387                         }
 388
 389                         ldlm_resource_add_lock(res, &res->lr_waiting, req);
 390                         *flags |= LDLM_FL_BLOCK_GRANTED;
 391                         RETURN(LDLM_ITER_STOP);
 392                 }
 393                 if (reprocess_failed)
 394                         RETURN(LDLM_ITER_CONTINUE);
 395         }
 396
 397         if (*flags & LDLM_FL_TEST_LOCK) {
 398                 ldlm_flock_destroy(req, mode, *flags);
 399                 req->l_req_mode = LCK_NL;
 400                 *flags |= LDLM_FL_LOCK_CHANGED;
 401                 RETURN(LDLM_ITER_STOP);
 402         }
 403
 404         /* In case we had slept on this lock request take it off of the
 405          * deadlock detection hash list. */
 406         ldlm_flock_blocking_unlink(req);
 407
 408         /* Scan the locks owned by this process that overlap this request.
 409          * We may have to merge or split existing locks. */
 410
 411         if (!ownlocks)
 412                 ownlocks = &res->lr_granted;
 413
 414         list_for_remaining_safe(ownlocks, tmp, &res->lr_granted) {
 415                 lock = list_entry(ownlocks, struct ldlm_lock, l_res_link);
 416
 417                 if (!ldlm_same_flock_owner(lock, new))
 418                         break;
 419
 420                 if (lock->l_granted_mode == mode) {
 421                         /* If the modes are the same then we need to process
 422                          * locks that overlap OR adjoin the new lock. The extra
 423                          * logic condition is necessary to deal with arithmetic
 424                          * overflow and underflow. */
 425                         if ((new->l_policy_data.l_flock.start >
 426                              (lock->l_policy_data.l_flock.end + 1))
 427                             && (lock->l_policy_data.l_flock.end !=
 428                                 OBD_OBJECT_EOF))
 429                                 continue;
 430
 431                         if ((new->l_policy_data.l_flock.end <
 432                              (lock->l_policy_data.l_flock.start - 1))
 433                             && (lock->l_policy_data.l_flock.start != 0))
 434                                 break;
 435
 436                         if (new->l_policy_data.l_flock.start <
 437                             lock->l_policy_data.l_flock.start) {
 438                                 lock->l_policy_data.l_flock.start =
 439                                         new->l_policy_data.l_flock.start;
 440                         } else {
 441                                 new->l_policy_data.l_flock.start =
 442                                         lock->l_policy_data.l_flock.start;
 443                         }
 444
 445                         if (new->l_policy_data.l_flock.end >
 446                             lock->l_policy_data.l_flock.end) {
 447                                 lock->l_policy_data.l_flock.end =
 448                                         new->l_policy_data.l_flock.end;
 449                         } else {
 450                                 new->l_policy_data.l_flock.end =
 451                                         lock->l_policy_data.l_flock.end;
 452                         }
 453
 454                         if (added) {
 455                                 ldlm_flock_destroy(lock, mode, *flags);
 456                         } else {
 457                                 new = lock;
 458                                 added = 1;
 459                         }
 460                         continue;
 461                 }
 462
 463                 if (new->l_policy_data.l_flock.start >
 464                     lock->l_policy_data.l_flock.end)
 465                         continue;
 466
 467                 if (new->l_policy_data.l_flock.end <
 468                     lock->l_policy_data.l_flock.start)
 469                         break;
 470
 471                 ++overlaps;
 472
 473                 if (new->l_policy_data.l_flock.start <=
 474                     lock->l_policy_data.l_flock.start) {
 475                         if (new->l_policy_data.l_flock.end <
 476                             lock->l_policy_data.l_flock.end) {
 477                                 lock->l_policy_data.l_flock.start =
 478                                         new->l_policy_data.l_flock.end + 1;
 479                                 break;
 480                         }
 481                         ldlm_flock_destroy(lock, lock->l_req_mode, *flags);
 482                         continue;
 483                 }
 484                 if (new->l_policy_data.l_flock.end >=
 485                     lock->l_policy_data.l_flock.end) {
 486                         lock->l_policy_data.l_flock.end =
 487                                 new->l_policy_data.l_flock.start - 1;
 488                         continue;
 489                 }
 490
 491                 /* split the existing lock into two locks */
 492
 493                 /* if this is an F_UNLCK operation then we could avoid
 494                  * allocating a new lock and use the req lock passed in
 495                  * with the request but this would complicate the reply
 496                  * processing since updates to req get reflected in the
 497                  * reply. The client side replays the lock request so
 498                  * it must see the original lock data in the reply. */
 499
 500                 /* XXX - if ldlm_lock_new() can sleep we should
 501                  * release the lr_lock, allocate the new lock,
 502                  * and restart processing this lock. */
 503                 if (new2 == NULL) {
 504                         unlock_res_and_lock(req);
 505                         new2 = ldlm_lock_create(ns, &res->lr_name, LDLM_FLOCK,
 506                                                 lock->l_granted_mode, &null_cbs,
 507                                                 NULL, 0, LVB_T_NONE);
 508                         lock_res_and_lock(req);
 509                         if (IS_ERR(new2)) {
 510                                 ldlm_flock_destroy(req, lock->l_granted_mode,
 511                                                    *flags);
 512                                 *err = PTR_ERR(new2);
 513                                 RETURN(LDLM_ITER_STOP);
 514                         }
 515                         goto reprocess;
 516                 }
 517
 518                 splitted = 1;
 519
 520                 new2->l_granted_mode = lock->l_granted_mode;
 521                 new2->l_policy_data.l_flock.pid =
 522                         new->l_policy_data.l_flock.pid;
 523                 new2->l_policy_data.l_flock.owner =
 524                         new->l_policy_data.l_flock.owner;
 525                 new2->l_policy_data.l_flock.start =
 526                         lock->l_policy_data.l_flock.start;
 527                 new2->l_policy_data.l_flock.end =
 528                         new->l_policy_data.l_flock.start - 1;
 529                 lock->l_policy_data.l_flock.start =
 530                         new->l_policy_data.l_flock.end + 1;
 531                 new2->l_conn_export = lock->l_conn_export;
 532                 if (lock->l_export != NULL) {
 533                         new2->l_export = class_export_lock_get(lock->l_export, new2);
 534                         if (new2->l_export->exp_lock_hash &&
 535                             hlist_unhashed(&new2->l_exp_hash))
 536                                 cfs_hash_add(new2->l_export->exp_lock_hash,
 537                                              &new2->l_remote_handle,
 538                                              &new2->l_exp_hash);
 539                 }
 540                 if (*flags == LDLM_FL_WAIT_NOREPROC)
 541                         ldlm_lock_addref_internal_nolock(new2,
 542                                                          lock->l_granted_mode);
 543
 544                 /* insert new2 at lock */
 545                 ldlm_resource_add_lock(res, ownlocks, new2);
 546                 LDLM_LOCK_RELEASE(new2);
 547                 break;
 548         }
 549
 550         /* if new2 is created but never used, destroy it*/
 551         if (splitted == 0 && new2 != NULL)
 552                 ldlm_lock_destroy_nolock(new2);
 553
 554         /* At this point we're granting the lock request. */
 555         req->l_granted_mode = req->l_req_mode;
 556
 557         /* Add req to the granted queue before calling ldlm_reprocess_all(). */
 558         if (!added) {
 559                 list_del_init(&req->l_res_link);
 560                 /* insert new lock before ownlocks in list. */
 561                 ldlm_resource_add_lock(res, ownlocks, req);
 562         }
 563
 564         if (*flags != LDLM_FL_WAIT_NOREPROC) {
 565 #ifdef HAVE_SERVER_SUPPORT
 566                 if (intention == LDLM_PROCESS_ENQUEUE) {
 567                         /* If this is an unlock, reprocess the waitq and
 568                          * send completions ASTs for locks that can now be
 569                          * granted. The only problem with doing this
 570                          * reprocessing here is that the completion ASTs for
 571                          * newly granted locks will be sent before the unlock
 572                          * completion is sent. It shouldn't be an issue. Also
 573                          * note that ldlm_process_flock_lock() will recurse,
 574                          * but only once because 'intention' won't be
 575                          * LDLM_PROCESS_ENQUEUE from ldlm_reprocess_queue. */
 576                         if ((mode == LCK_NL) && overlaps) {
 577                                 struct list_head rpc_list;
 578                                 int rc;
 579
 580                                 INIT_LIST_HEAD(&rpc_list);
 581 restart:
 582                                 ldlm_reprocess_queue(res, &res->lr_waiting,
 583                                                      &rpc_list,
 584                                                      LDLM_PROCESS_RESCAN, NULL);
 585
 586                                 unlock_res_and_lock(req);
 587                                 rc = ldlm_run_ast_work(ns, &rpc_list,
 588                                                        LDLM_WORK_CP_AST);
 589                                 lock_res_and_lock(req);
 590                                 if (rc == -ERESTART)
 591                                         GOTO(restart, rc);
 592                        }
 593                 } else {
 594                         LASSERT(req->l_completion_ast);
 595                         ldlm_add_ast_work_item(req, NULL, grant_work);
 596                 }
 597 #else /* !HAVE_SERVER_SUPPORT */
 598                 /* The only one possible case for client-side calls flock
 599                  * policy function is ldlm_flock_completion_ast inside which
 600                  * carries LDLM_FL_WAIT_NOREPROC flag. */
 601                 CERROR("Illegal parameter for client-side-only module.\n");
 602                 LBUG();
 603 #endif /* HAVE_SERVER_SUPPORT */
 604         }
 605
 606         /* In case we're reprocessing the requested lock we can't destroy
 607          * it until after calling ldlm_add_ast_work_item() above so that laawi()
 608          * can bump the reference count on \a req. Otherwise \a req
 609          * could be freed before the completion AST can be sent.  */
 610         if (added)
 611                 ldlm_flock_destroy(req, mode, *flags);
 612
 613         ldlm_resource_dump(D_INFO, res);
 614         RETURN(LDLM_ITER_CONTINUE);
 615 }
 616
 617 struct ldlm_flock_wait_data {
 618         struct ldlm_lock *fwd_lock;
 619         int               fwd_generation;
 620 };
 621
 622 static void
 623 ldlm_flock_interrupted_wait(void *data)
 624 {
 625         struct ldlm_lock *lock;
 626         ENTRY;
 627
 628         lock = ((struct ldlm_flock_wait_data *)data)->fwd_lock;
 629
 630         /* take lock off the deadlock detection hash list. */
 631         lock_res_and_lock(lock);
 632         ldlm_flock_blocking_unlink(lock);
 633
 634         /* client side - set flag to prevent lock from being put on LRU list */
 635         ldlm_set_cbpending(lock);
 636         unlock_res_and_lock(lock);
 637
 638         EXIT;
 639 }
 640
 641 /**
 642  * Flock completion callback function.
 643  *
 644  * \param lock [in,out]: A lock to be handled
 645  * \param flags    [in]: flags
 646  * \param *data    [in]: ldlm_work_cp_ast_lock() will use ldlm_cb_set_arg
 647  *
 648  * \retval 0    : success
 649  * \retval <0   : failure
 650  */
 651 int
 652 ldlm_flock_completion_ast(struct ldlm_lock *lock, __u64 flags, void *data)
 653 {
 654         struct file_lock *getlk = lock->l_ast_data;
 655         struct obd_device *obd;
 656         struct obd_import *imp = NULL;
 657         struct ldlm_flock_wait_data fwd;
 658         struct l_wait_info lwi;
 659         enum ldlm_error err;
 660         int rc = 0;
 661         ENTRY;
 662
 663         OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT2, 4);
 664         if (OBD_FAIL_PRECHECK(OBD_FAIL_LDLM_CP_CB_WAIT3)) {
 665                 lock_res_and_lock(lock);
 666                 lock->l_flags |= LDLM_FL_FAIL_LOC;
 667                 unlock_res_and_lock(lock);
 668                 OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT3, 4);
 669         }
 670         CDEBUG(D_DLMTRACE, "flags: %#llx data: %p getlk: %p\n",
 671                flags, data, getlk);
 672
 673         LASSERT(flags != LDLM_FL_WAIT_NOREPROC);
 674
 675         if (flags & LDLM_FL_FAILED)
 676                 goto granted;
 677
 678         if (!(flags & LDLM_FL_BLOCKED_MASK)) {
 679                 if (NULL == data)
 680                         /* mds granted the lock in the reply */
 681                         goto granted;
 682                 /* CP AST RPC: lock get granted, wake it up */
 683                 wake_up(&lock->l_waitq);
 684                 RETURN(0);
 685         }
 686
 687         LDLM_DEBUG(lock, "client-side enqueue returned a blocked lock, "
 688                    "sleeping");
 689         fwd.fwd_lock = lock;
 690         obd = class_exp2obd(lock->l_conn_export);
 691
 692         /* if this is a local lock, there is no import */
 693         if (NULL != obd)
 694                 imp = obd->u.cli.cl_import;
 695
 696         if (NULL != imp) {
 697                 spin_lock(&imp->imp_lock);
 698                 fwd.fwd_generation = imp->imp_generation;
 699                 spin_unlock(&imp->imp_lock);
 700         }
 701
 702         lwi = LWI_TIMEOUT_INTR(0, NULL, ldlm_flock_interrupted_wait, &fwd);
 703
 704         /* Go to sleep until the lock is granted. */
 705         rc = l_wait_event(lock->l_waitq, is_granted_or_cancelled(lock), &lwi);
 706
 707         if (rc) {
 708                 LDLM_DEBUG(lock, "client-side enqueue waking up: failed (%d)",
 709                            rc);
 710                 RETURN(rc);
 711         }
 712
 713 granted:
 714         OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT, 10);
 715
 716         if (OBD_FAIL_PRECHECK(OBD_FAIL_LDLM_CP_CB_WAIT4)) {
 717                 lock_res_and_lock(lock);
 718                 /* DEADLOCK is always set with CBPENDING */
 719                 lock->l_flags |= LDLM_FL_FLOCK_DEADLOCK | LDLM_FL_CBPENDING;
 720                 unlock_res_and_lock(lock);
 721                 OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT4, 4);
 722         }
 723         if (OBD_FAIL_PRECHECK(OBD_FAIL_LDLM_CP_CB_WAIT5)) {
 724                 lock_res_and_lock(lock);
 725                 /* DEADLOCK is always set with CBPENDING */
 726                 lock->l_flags |= LDLM_FL_FAIL_LOC |
 727                                  LDLM_FL_FLOCK_DEADLOCK | LDLM_FL_CBPENDING;
 728                 unlock_res_and_lock(lock);
 729                 OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT5, 4);
 730         }
 731
 732         lock_res_and_lock(lock);
 733
 734
 735         /* Protect against race where lock could have been just destroyed
 736          * due to overlap in ldlm_process_flock_lock().
 737          */
 738         if (ldlm_is_destroyed(lock)) {
 739                 unlock_res_and_lock(lock);
 740                 LDLM_DEBUG(lock, "client-side enqueue waking up: destroyed");
 741
 742                 /* An error is still to be returned, to propagate it up to
 743                  * ldlm_cli_enqueue_fini() caller. */
 744                 RETURN(-EIO);
 745         }
 746
 747         /* ldlm_lock_enqueue() has already placed lock on the granted list. */
 748         ldlm_resource_unlink_lock(lock);
 749
 750         /* Import invalidation. We need to actually release the lock
 751          * references being held, so that it can go away. No point in
 752          * holding the lock even if app still believes it has it, since
 753          * server already dropped it anyway. Only for granted locks too. */
 754         /* Do the same for DEADLOCK'ed locks. */
 755         if (ldlm_is_failed(lock) || ldlm_is_flock_deadlock(lock)) {
 756                 int mode;
 757
 758                 if (flags & LDLM_FL_TEST_LOCK)
 759                         LASSERT(ldlm_is_test_lock(lock));
 760
 761                 if (ldlm_is_test_lock(lock) || ldlm_is_flock_deadlock(lock))
 762                         mode = getlk->fl_type;
 763                 else
 764                         mode = lock->l_granted_mode;
 765
 766                 if (ldlm_is_flock_deadlock(lock)) {
 767                         LDLM_DEBUG(lock, "client-side enqueue deadlock "
 768                                    "received");
 769                         rc = -EDEADLK;
 770                 }
 771                 ldlm_flock_destroy(lock, mode, LDLM_FL_WAIT_NOREPROC);
 772                 unlock_res_and_lock(lock);
 773
 774                 /* Need to wake up the waiter if we were evicted */
 775                 wake_up(&lock->l_waitq);
 776
 777                 /* An error is still to be returned, to propagate it up to
 778                  * ldlm_cli_enqueue_fini() caller. */
 779                 RETURN(rc ? : -EIO);
 780         }
 781
 782         LDLM_DEBUG(lock, "client-side enqueue granted");
 783
 784         if (flags & LDLM_FL_TEST_LOCK) {
 785                 /*
 786                  * fcntl(F_GETLK) request
 787                  * The old mode was saved in getlk->fl_type so that if the mode
 788                  * in the lock changes we can decref the appropriate refcount.
 789                  */
 790                 LASSERT(ldlm_is_test_lock(lock));
 791                 ldlm_flock_destroy(lock, getlk->fl_type, LDLM_FL_WAIT_NOREPROC);
 792                 switch (lock->l_granted_mode) {
 793                 case LCK_PR:
 794                         getlk->fl_type = F_RDLCK;
 795                         break;
 796                 case LCK_PW:
 797                         getlk->fl_type = F_WRLCK;
 798                         break;
 799                 default:
 800                         getlk->fl_type = F_UNLCK;
 801                 }
 802                 getlk->fl_pid = (pid_t)lock->l_policy_data.l_flock.pid;
 803                 getlk->fl_start = (loff_t)lock->l_policy_data.l_flock.start;
 804                 getlk->fl_end = (loff_t)lock->l_policy_data.l_flock.end;
 805         } else {
 806                 __u64 noreproc = LDLM_FL_WAIT_NOREPROC;
 807
 808                 /* We need to reprocess the lock to do merges or splits
 809                  * with existing locks owned by this process. */
 810                 ldlm_process_flock_lock(lock, &noreproc, 1, &err, NULL);
 811         }
 812         unlock_res_and_lock(lock);
 813         RETURN(rc);
 814 }
 815 EXPORT_SYMBOL(ldlm_flock_completion_ast);
 816
 817 int ldlm_flock_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
 818                             void *data, int flag)
 819 {
 820         ENTRY;
 821
 822         LASSERT(lock);
 823         LASSERT(flag == LDLM_CB_CANCELING);
 824
 825         /* take lock off the deadlock detection hash list. */
 826         lock_res_and_lock(lock);
 827         ldlm_flock_blocking_unlink(lock);
 828         unlock_res_and_lock(lock);
 829         RETURN(0);
 830 }
 831
 832 void ldlm_flock_policy_wire_to_local(const union ldlm_wire_policy_data *wpolicy,
 833                                      union ldlm_policy_data *lpolicy)
 834 {
 835         lpolicy->l_flock.start = wpolicy->l_flock.lfw_start;
 836         lpolicy->l_flock.end = wpolicy->l_flock.lfw_end;
 837         lpolicy->l_flock.pid = wpolicy->l_flock.lfw_pid;
 838         lpolicy->l_flock.owner = wpolicy->l_flock.lfw_owner;
 839 }
 840
 841 void ldlm_flock_policy_local_to_wire(const union ldlm_policy_data *lpolicy,
 842                                      union ldlm_wire_policy_data *wpolicy)
 843 {
 844         memset(wpolicy, 0, sizeof(*wpolicy));
 845         wpolicy->l_flock.lfw_start = lpolicy->l_flock.start;
 846         wpolicy->l_flock.lfw_end = lpolicy->l_flock.end;
 847         wpolicy->l_flock.lfw_pid = lpolicy->l_flock.pid;
 848         wpolicy->l_flock.lfw_owner = lpolicy->l_flock.owner;
 849 }
 850
 851 /*
 852  * Export handle<->flock hash operations.
 853  */
 854 static unsigned
 855 ldlm_export_flock_hash(struct cfs_hash *hs, const void *key, unsigned mask)
 856 {
 857         return cfs_hash_u64_hash(*(__u64 *)key, mask);
 858 }
 859
 860 static void *
 861 ldlm_export_flock_key(struct hlist_node *hnode)
 862 {
 863         struct ldlm_lock *lock;
 864
 865         lock = hlist_entry(hnode, struct ldlm_lock, l_exp_flock_hash);
 866         return &lock->l_policy_data.l_flock.owner;
 867 }
 868
 869 static int
 870 ldlm_export_flock_keycmp(const void *key, struct hlist_node *hnode)
 871 {
 872         return !memcmp(ldlm_export_flock_key(hnode), key, sizeof(__u64));
 873 }
 874
 875 static void *
 876 ldlm_export_flock_object(struct hlist_node *hnode)
 877 {
 878         return hlist_entry(hnode, struct ldlm_lock, l_exp_flock_hash);
 879 }
 880
 881 static void
 882 ldlm_export_flock_get(struct cfs_hash *hs, struct hlist_node *hnode)
 883 {
 884         struct ldlm_lock *lock;
 885         struct ldlm_flock *flock;
 886
 887         lock = hlist_entry(hnode, struct ldlm_lock, l_exp_flock_hash);
 888         LDLM_LOCK_GET(lock);
 889
 890         flock = &lock->l_policy_data.l_flock;
 891         LASSERT(flock->blocking_export != NULL);
 892         class_export_get(flock->blocking_export);
 893         atomic_inc(&flock->blocking_refs);
 894 }
 895
 896 static void
 897 ldlm_export_flock_put(struct cfs_hash *hs, struct hlist_node *hnode)
 898 {
 899         struct ldlm_lock *lock;
 900         struct ldlm_flock *flock;
 901
 902         lock = hlist_entry(hnode, struct ldlm_lock, l_exp_flock_hash);
 903
 904         flock = &lock->l_policy_data.l_flock;
 905         LASSERT(flock->blocking_export != NULL);
 906         class_export_put(flock->blocking_export);
 907         if (atomic_dec_and_test(&flock->blocking_refs)) {
 908                 flock->blocking_owner = 0;
 909                 flock->blocking_export = NULL;
 910         }
 911         LDLM_LOCK_RELEASE(lock);
 912 }
 913
 914 static struct cfs_hash_ops ldlm_export_flock_ops = {
 915         .hs_hash        = ldlm_export_flock_hash,
 916         .hs_key         = ldlm_export_flock_key,
 917         .hs_keycmp      = ldlm_export_flock_keycmp,
 918         .hs_object      = ldlm_export_flock_object,
 919         .hs_get         = ldlm_export_flock_get,
 920         .hs_put         = ldlm_export_flock_put,
 921         .hs_put_locked  = ldlm_export_flock_put,
 922 };
 923
 924 int ldlm_init_flock_export(struct obd_export *exp)
 925 {
 926         if( strcmp(exp->exp_obd->obd_type->typ_name, LUSTRE_MDT_NAME) != 0)
 927                 RETURN(0);
 928
 929         exp->exp_flock_hash =
 930                 cfs_hash_create(obd_uuid2str(&exp->exp_client_uuid),
 931                                 HASH_EXP_LOCK_CUR_BITS,
 932                                 HASH_EXP_LOCK_MAX_BITS,
 933                                 HASH_EXP_LOCK_BKT_BITS, 0,
 934                                 CFS_HASH_MIN_THETA, CFS_HASH_MAX_THETA,
 935                                 &ldlm_export_flock_ops,
 936                                 CFS_HASH_DEFAULT | CFS_HASH_NBLK_CHANGE);
 937         if (!exp->exp_flock_hash)
 938                 RETURN(-ENOMEM);
 939
 940         RETURN(0);
 941 }
 942
 943 void ldlm_destroy_flock_export(struct obd_export *exp)
 944 {
 945         ENTRY;
 946         if (exp->exp_flock_hash) {
 947                 cfs_hash_putref(exp->exp_flock_hash);
 948                 exp->exp_flock_hash = NULL;
 949         }
 950         EXIT;
 951 }