fs/ocfs2/dlm/dlmast.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * dlmast.c
   5  *
   6  * AST and BAST functionality for local and remote nodes
   7  *
   8  * Copyright (C) 2004 Oracle.  All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2 of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public
  21  * License along with this program; if not, write to the
  22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23  * Boston, MA 021110-1307, USA.
  24  *
  25  */
  26
  27
  28 #include <linux/module.h>
  29 #include <linux/fs.h>
  30 #include <linux/types.h>
  31 #include <linux/highmem.h>
  32 #include <linux/init.h>
  33 #include <linux/sysctl.h>
  34 #include <linux/random.h>
  35 #include <linux/blkdev.h>
  36 #include <linux/socket.h>
  37 #include <linux/inet.h>
  38 #include <linux/spinlock.h>
  39
  40
  41 #include "cluster/heartbeat.h"
  42 #include "cluster/nodemanager.h"
  43 #include "cluster/tcp.h"
  44
  45 #include "dlmapi.h"
  46 #include "dlmcommon.h"
  47
  48 #define MLOG_MASK_PREFIX ML_DLM
  49 #include "cluster/masklog.h"
  50
  51 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
  52                            struct dlm_lock *lock);
  53 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
  54
  55 /* Should be called as an ast gets queued to see if the new
  56  * lock level will obsolete a pending bast.
  57  * For example, if dlm_thread queued a bast for an EX lock that
  58  * was blocking another EX, but before sending the bast the
  59  * lock owner downconverted to NL, the bast is now obsolete.
  60  * Only the ast should be sent.
  61  * This is needed because the lock and convert paths can queue
  62  * asts out-of-band (not waiting for dlm_thread) in order to
  63  * allow for LKM_NOQUEUE to get immediate responses. */
  64 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
  65 {
  66         assert_spin_locked(&dlm->ast_lock);
  67         assert_spin_locked(&lock->spinlock);
  68
  69         if (lock->ml.highest_blocked == LKM_IVMODE)
  70                 return 0;
  71         BUG_ON(lock->ml.highest_blocked == LKM_NLMODE);
  72
  73         if (lock->bast_pending &&
  74             list_empty(&lock->bast_list))
  75                 /* old bast already sent, ok */
  76                 return 0;
  77
  78         if (lock->ml.type == LKM_EXMODE)
  79                 /* EX blocks anything left, any bast still valid */
  80                 return 0;
  81         else if (lock->ml.type == LKM_NLMODE)
  82                 /* NL blocks nothing, no reason to send any bast, cancel it */
  83                 return 1;
  84         else if (lock->ml.highest_blocked != LKM_EXMODE)
  85                 /* PR only blocks EX */
  86                 return 1;
  87
  88         return 0;
  89 }
  90
  91 void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
  92 {
  93         struct dlm_lock_resource *res;
  94
  95         BUG_ON(!dlm);
  96         BUG_ON(!lock);
  97
  98         res = lock->lockres;
  99
 100         assert_spin_locked(&dlm->ast_lock);
 101
 102         if (!list_empty(&lock->ast_list)) {
 103                 mlog(ML_ERROR, "%s: res %.*s, lock %u:%llu, "
 104                      "AST list not empty, pending %d, newlevel %d\n",
 105                      dlm->name, res->lockname.len, res->lockname.name,
 106                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 107                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
 108                      lock->ast_pending, lock->ml.type);
 109                 BUG();
 110         }
 111         if (lock->ast_pending)
 112                 mlog(0, "%s: res %.*s, lock %u:%llu, AST getting flushed\n",
 113                      dlm->name, res->lockname.len, res->lockname.name,
 114                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 115                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
 116
 117         /* putting lock on list, add a ref */
 118         dlm_lock_get(lock);
 119         spin_lock(&lock->spinlock);
 120
 121         /* check to see if this ast obsoletes the bast */
 122         if (dlm_should_cancel_bast(dlm, lock)) {
 123                 mlog(0, "%s: res %.*s, lock %u:%llu, Cancelling BAST\n",
 124                      dlm->name, res->lockname.len, res->lockname.name,
 125                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 126                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
 127                 lock->bast_pending = 0;
 128                 list_del_init(&lock->bast_list);
 129                 lock->ml.highest_blocked = LKM_IVMODE;
 130                 /* removing lock from list, remove a ref.  guaranteed
 131                  * this won't be the last ref because of the get above,
 132                  * so res->spinlock will not be taken here */
 133                 dlm_lock_put(lock);
 134                 /* free up the reserved bast that we are cancelling.
 135                  * guaranteed that this will not be the last reserved
 136                  * ast because *both* an ast and a bast were reserved
 137                  * to get to this point.  the res->spinlock will not be
 138                  * taken here */
 139                 dlm_lockres_release_ast(dlm, res);
 140         }
 141         list_add_tail(&lock->ast_list, &dlm->pending_asts);
 142         lock->ast_pending = 1;
 143         spin_unlock(&lock->spinlock);
 144 }
 145
 146 void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 147 {
 148         BUG_ON(!dlm);
 149         BUG_ON(!lock);
 150
 151         spin_lock(&dlm->ast_lock);
 152         __dlm_queue_ast(dlm, lock);
 153         spin_unlock(&dlm->ast_lock);
 154 }
 155
 156
 157 void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 158 {
 159         struct dlm_lock_resource *res;
 160
 161         BUG_ON(!dlm);
 162         BUG_ON(!lock);
 163
 164         assert_spin_locked(&dlm->ast_lock);
 165
 166         res = lock->lockres;
 167
 168         BUG_ON(!list_empty(&lock->bast_list));
 169         if (lock->bast_pending)
 170                 mlog(0, "%s: res %.*s, lock %u:%llu, BAST getting flushed\n",
 171                      dlm->name, res->lockname.len, res->lockname.name,
 172                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 173                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
 174
 175         /* putting lock on list, add a ref */
 176         dlm_lock_get(lock);
 177         spin_lock(&lock->spinlock);
 178         list_add_tail(&lock->bast_list, &dlm->pending_basts);
 179         lock->bast_pending = 1;
 180         spin_unlock(&lock->spinlock);
 181 }
 182
 183 void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 184 {
 185         BUG_ON(!dlm);
 186         BUG_ON(!lock);
 187
 188         spin_lock(&dlm->ast_lock);
 189         __dlm_queue_bast(dlm, lock);
 190         spin_unlock(&dlm->ast_lock);
 191 }
 192
 193 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 194                            struct dlm_lock *lock)
 195 {
 196         struct dlm_lockstatus *lksb = lock->lksb;
 197         BUG_ON(!lksb);
 198
 199         /* only updates if this node masters the lockres */
 200         spin_lock(&res->spinlock);
 201         if (res->owner == dlm->node_num) {
 202                 /* check the lksb flags for the direction */
 203                 if (lksb->flags & DLM_LKSB_GET_LVB) {
 204                         mlog(0, "getting lvb from lockres for %s node\n",
 205                                   lock->ml.node == dlm->node_num ? "master" :
 206                                   "remote");
 207                         memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
 208                 }
 209                 /* Do nothing for lvb put requests - they should be done in
 210                  * place when the lock is downconverted - otherwise we risk
 211                  * racing gets and puts which could result in old lvb data
 212                  * being propagated. We leave the put flag set and clear it
 213                  * here. In the future we might want to clear it at the time
 214                  * the put is actually done.
 215                  */
 216         }
 217         spin_unlock(&res->spinlock);
 218
 219         /* reset any lvb flags on the lksb */
 220         lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
 221 }
 222
 223 void dlm_do_local_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 224                       struct dlm_lock *lock)
 225 {
 226         dlm_astlockfunc_t *fn;
 227
 228         mlog(0, "%s: res %.*s, lock %u:%llu, Local AST\n", dlm->name,
 229              res->lockname.len, res->lockname.name,
 230              dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 231              dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
 232
 233         fn = lock->ast;
 234         BUG_ON(lock->ml.node != dlm->node_num);
 235
 236         dlm_update_lvb(dlm, res, lock);
 237         (*fn)(lock->astdata);
 238 }
 239
 240
 241 int dlm_do_remote_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 242                       struct dlm_lock *lock)
 243 {
 244         int ret;
 245         struct dlm_lockstatus *lksb;
 246         int lksbflags;
 247
 248         mlog(0, "%s: res %.*s, lock %u:%llu, Remote AST\n", dlm->name,
 249              res->lockname.len, res->lockname.name,
 250              dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 251              dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
 252
 253         lksb = lock->lksb;
 254         BUG_ON(lock->ml.node == dlm->node_num);
 255
 256         lksbflags = lksb->flags;
 257         dlm_update_lvb(dlm, res, lock);
 258
 259         /* lock request came from another node
 260          * go do the ast over there */
 261         ret = dlm_send_proxy_ast(dlm, res, lock, lksbflags);
 262         return ret;
 263 }
 264
 265 void dlm_do_local_bast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 266                        struct dlm_lock *lock, int blocked_type)
 267 {
 268         dlm_bastlockfunc_t *fn = lock->bast;
 269
 270         BUG_ON(lock->ml.node != dlm->node_num);
 271
 272         mlog(0, "%s: res %.*s, lock %u:%llu, Local BAST, blocked %d\n",
 273              dlm->name, res->lockname.len, res->lockname.name,
 274              dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 275              dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
 276              blocked_type);
 277
 278         (*fn)(lock->astdata, blocked_type);
 279 }
 280
 281
 282
 283 int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *data,
 284                           void **ret_data)
 285 {
 286         int ret;
 287         unsigned int locklen;
 288         struct dlm_ctxt *dlm = data;
 289         struct dlm_lock_resource *res = NULL;
 290         struct dlm_lock *lock = NULL;
 291         struct dlm_proxy_ast *past = (struct dlm_proxy_ast *) msg->buf;
 292         char *name;
 293         struct list_head *head = NULL;
 294         __be64 cookie;
 295         u32 flags;
 296         u8 node;
 297
 298         if (!dlm_grab(dlm)) {
 299                 dlm_error(DLM_REJECTED);
 300                 return DLM_REJECTED;
 301         }
 302
 303         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
 304                         "Domain %s not fully joined!\n", dlm->name);
 305
 306         name = past->name;
 307         locklen = past->namelen;
 308         cookie = past->cookie;
 309         flags = be32_to_cpu(past->flags);
 310         node = past->node_idx;
 311
 312         if (locklen > DLM_LOCKID_NAME_MAX) {
 313                 ret = DLM_IVBUFLEN;
 314                 mlog(ML_ERROR, "Invalid name length (%d) in proxy ast "
 315                      "handler!\n", locklen);
 316                 goto leave;
 317         }
 318
 319         if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
 320              (LKM_PUT_LVB|LKM_GET_LVB)) {
 321                 mlog(ML_ERROR, "Both PUT and GET lvb specified, (0x%x)\n",
 322                      flags);
 323                 ret = DLM_BADARGS;
 324                 goto leave;
 325         }
 326
 327         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
 328                   (flags & LKM_GET_LVB ? "get lvb" : "none"));
 329
 330         mlog(0, "type=%d, blocked_type=%d\n", past->type, past->blocked_type);
 331
 332         if (past->type != DLM_AST &&
 333             past->type != DLM_BAST) {
 334                 mlog(ML_ERROR, "Unknown ast type! %d, cookie=%u:%llu"
 335                      "name=%.*s, node=%u\n", past->type,
 336                      dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
 337                      dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
 338                      locklen, name, node);
 339                 ret = DLM_IVLOCKID;
 340                 goto leave;
 341         }
 342
 343         res = dlm_lookup_lockres(dlm, name, locklen);
 344         if (!res) {
 345                 mlog(0, "Got %sast for unknown lockres! cookie=%u:%llu, "
 346                      "name=%.*s, node=%u\n", (past->type == DLM_AST ? "" : "b"),
 347                      dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
 348                      dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
 349                      locklen, name, node);
 350                 ret = DLM_IVLOCKID;
 351                 goto leave;
 352         }
 353
 354         /* cannot get a proxy ast message if this node owns it */
 355         BUG_ON(res->owner == dlm->node_num);
 356
 357         mlog(0, "%s: res %.*s\n", dlm->name, res->lockname.len,
 358              res->lockname.name);
 359
 360         spin_lock(&res->spinlock);
 361         if (res->state & DLM_LOCK_RES_RECOVERING) {
 362                 mlog(0, "Responding with DLM_RECOVERING!\n");
 363                 ret = DLM_RECOVERING;
 364                 goto unlock_out;
 365         }
 366         if (res->state & DLM_LOCK_RES_MIGRATING) {
 367                 mlog(0, "Responding with DLM_MIGRATING!\n");
 368                 ret = DLM_MIGRATING;
 369                 goto unlock_out;
 370         }
 371         /* try convert queue for both ast/bast */
 372         head = &res->converting;
 373         lock = NULL;
 374         list_for_each_entry(lock, head, list) {
 375                 if (lock->ml.cookie == cookie)
 376                         goto do_ast;
 377         }
 378
 379         /* if not on convert, try blocked for ast, granted for bast */
 380         if (past->type == DLM_AST)
 381                 head = &res->blocked;
 382         else
 383                 head = &res->granted;
 384
 385         list_for_each_entry(lock, head, list) {
 386                 /* if lock is found but unlock is pending ignore the bast */
 387                 if (lock->ml.cookie == cookie) {
 388                         if (lock->unlock_pending)
 389                                 break;
 390                         goto do_ast;
 391                 }
 392         }
 393
 394         mlog(0, "Got %sast for unknown lock! cookie=%u:%llu, name=%.*s, "
 395              "node=%u\n", past->type == DLM_AST ? "" : "b",
 396              dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
 397              dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
 398              locklen, name, node);
 399
 400         ret = DLM_NORMAL;
 401 unlock_out:
 402         spin_unlock(&res->spinlock);
 403         goto leave;
 404
 405 do_ast:
 406         ret = DLM_NORMAL;
 407         if (past->type == DLM_AST) {
 408                 /* do not alter lock refcount.  switching lists. */
 409                 list_move_tail(&lock->list, &res->granted);
 410                 mlog(0, "%s: res %.*s, lock %u:%llu, Granted type %d => %d\n",
 411                      dlm->name, res->lockname.len, res->lockname.name,
 412                      dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
 413                      dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
 414                      lock->ml.type, lock->ml.convert_type);
 415
 416                 if (lock->ml.convert_type != LKM_IVMODE) {
 417                         lock->ml.type = lock->ml.convert_type;
 418                         lock->ml.convert_type = LKM_IVMODE;
 419                 } else {
 420                         // should already be there....
 421                 }
 422
 423                 lock->lksb->status = DLM_NORMAL;
 424
 425                 /* if we requested the lvb, fetch it into our lksb now */
 426                 if (flags & LKM_GET_LVB) {
 427                         BUG_ON(!(lock->lksb->flags & DLM_LKSB_GET_LVB));
 428                         memcpy(lock->lksb->lvb, past->lvb, DLM_LVB_LEN);
 429                 }
 430         }
 431         spin_unlock(&res->spinlock);
 432
 433         if (past->type == DLM_AST)
 434                 dlm_do_local_ast(dlm, res, lock);
 435         else
 436                 dlm_do_local_bast(dlm, res, lock, past->blocked_type);
 437
 438 leave:
 439         if (res)
 440                 dlm_lockres_put(res);
 441
 442         dlm_put(dlm);
 443         return ret;
 444 }
 445
 446
 447
 448 int dlm_send_proxy_ast_msg(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 449                            struct dlm_lock *lock, int msg_type,
 450                            int blocked_type, int flags)
 451 {
 452         int ret = 0;
 453         struct dlm_proxy_ast past;
 454         struct kvec vec[2];
 455         size_t veclen = 1;
 456         int status;
 457
 458         mlog(0, "%s: res %.*s, to %u, type %d, blocked_type %d\n", dlm->name,
 459              res->lockname.len, res->lockname.name, lock->ml.node, msg_type,
 460              blocked_type);
 461
 462         memset(&past, 0, sizeof(struct dlm_proxy_ast));
 463         past.node_idx = dlm->node_num;
 464         past.type = msg_type;
 465         past.blocked_type = blocked_type;
 466         past.namelen = res->lockname.len;
 467         memcpy(past.name, res->lockname.name, past.namelen);
 468         past.cookie = lock->ml.cookie;
 469
 470         vec[0].iov_len = sizeof(struct dlm_proxy_ast);
 471         vec[0].iov_base = &past;
 472         if (flags & DLM_LKSB_GET_LVB) {
 473                 be32_add_cpu(&past.flags, LKM_GET_LVB);
 474                 vec[1].iov_len = DLM_LVB_LEN;
 475                 vec[1].iov_base = lock->lksb->lvb;
 476                 veclen++;
 477         }
 478
 479         ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
 480                                      lock->ml.node, &status);
 481         if (ret < 0)
 482                 mlog(ML_ERROR, "%s: res %.*s, error %d send AST to node %u\n",
 483                      dlm->name, res->lockname.len, res->lockname.name, ret,
 484                      lock->ml.node);
 485         else {
 486                 if (status == DLM_RECOVERING) {
 487                         mlog(ML_ERROR, "sent AST to node %u, it thinks this "
 488                              "node is dead!\n", lock->ml.node);
 489                         BUG();
 490                 } else if (status == DLM_MIGRATING) {
 491                         mlog(ML_ERROR, "sent AST to node %u, it returned "
 492                              "DLM_MIGRATING!\n", lock->ml.node);
 493                         BUG();
 494                 } else if (status != DLM_NORMAL && status != DLM_IVLOCKID) {
 495                         mlog(ML_ERROR, "AST to node %u returned %d!\n",
 496                              lock->ml.node, status);
 497                         /* ignore it */
 498                 }
 499                 ret = 0;
 500         }
 501         return ret;
 502 }