release/src-rt-6.x.4708/linux/linux-2.6.36/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         mlog_entry_void();
  94
  95         BUG_ON(!dlm);
  96         BUG_ON(!lock);
  97
  98         assert_spin_locked(&dlm->ast_lock);
  99         if (!list_empty(&lock->ast_list)) {
 100                 mlog(ML_ERROR, "ast list not empty!!  pending=%d, newlevel=%d\n",
 101                      lock->ast_pending, lock->ml.type);
 102                 BUG();
 103         }
 104         if (lock->ast_pending)
 105                 mlog(0, "lock has an ast getting flushed right now\n");
 106
 107         /* putting lock on list, add a ref */
 108         dlm_lock_get(lock);
 109         spin_lock(&lock->spinlock);
 110
 111         /* check to see if this ast obsoletes the bast */
 112         if (dlm_should_cancel_bast(dlm, lock)) {
 113                 struct dlm_lock_resource *res = lock->lockres;
 114                 mlog(0, "%s: cancelling bast for %.*s\n",
 115                      dlm->name, res->lockname.len, res->lockname.name);
 116                 lock->bast_pending = 0;
 117                 list_del_init(&lock->bast_list);
 118                 lock->ml.highest_blocked = LKM_IVMODE;
 119                 /* removing lock from list, remove a ref.  guaranteed
 120                  * this won't be the last ref because of the get above,
 121                  * so res->spinlock will not be taken here */
 122                 dlm_lock_put(lock);
 123                 /* free up the reserved bast that we are cancelling.
 124                  * guaranteed that this will not be the last reserved
 125                  * ast because *both* an ast and a bast were reserved
 126                  * to get to this point.  the res->spinlock will not be
 127                  * taken here */
 128                 dlm_lockres_release_ast(dlm, res);
 129         }
 130         list_add_tail(&lock->ast_list, &dlm->pending_asts);
 131         lock->ast_pending = 1;
 132         spin_unlock(&lock->spinlock);
 133 }
 134
 135 void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 136 {
 137         mlog_entry_void();
 138
 139         BUG_ON(!dlm);
 140         BUG_ON(!lock);
 141
 142         spin_lock(&dlm->ast_lock);
 143         __dlm_queue_ast(dlm, lock);
 144         spin_unlock(&dlm->ast_lock);
 145 }
 146
 147
 148 void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 149 {
 150         mlog_entry_void();
 151
 152         BUG_ON(!dlm);
 153         BUG_ON(!lock);
 154         assert_spin_locked(&dlm->ast_lock);
 155
 156         BUG_ON(!list_empty(&lock->bast_list));
 157         if (lock->bast_pending)
 158                 mlog(0, "lock has a bast getting flushed right now\n");
 159
 160         /* putting lock on list, add a ref */
 161         dlm_lock_get(lock);
 162         spin_lock(&lock->spinlock);
 163         list_add_tail(&lock->bast_list, &dlm->pending_basts);
 164         lock->bast_pending = 1;
 165         spin_unlock(&lock->spinlock);
 166 }
 167
 168 void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 169 {
 170         mlog_entry_void();
 171
 172         BUG_ON(!dlm);
 173         BUG_ON(!lock);
 174
 175         spin_lock(&dlm->ast_lock);
 176         __dlm_queue_bast(dlm, lock);
 177         spin_unlock(&dlm->ast_lock);
 178 }
 179
 180 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 181                            struct dlm_lock *lock)
 182 {
 183         struct dlm_lockstatus *lksb = lock->lksb;
 184         BUG_ON(!lksb);
 185
 186         /* only updates if this node masters the lockres */
 187         spin_lock(&res->spinlock);
 188         if (res->owner == dlm->node_num) {
 189                 /* check the lksb flags for the direction */
 190                 if (lksb->flags & DLM_LKSB_GET_LVB) {
 191                         mlog(0, "getting lvb from lockres for %s node\n",
 192                                   lock->ml.node == dlm->node_num ? "master" :
 193                                   "remote");
 194                         memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
 195                 }
 196                 /* Do nothing for lvb put requests - they should be done in
 197                  * place when the lock is downconverted - otherwise we risk
 198                  * racing gets and puts which could result in old lvb data
 199                  * being propagated. We leave the put flag set and clear it
 200                  * here. In the future we might want to clear it at the time
 201                  * the put is actually done.
 202                  */
 203         }
 204         spin_unlock(&res->spinlock);
 205
 206         /* reset any lvb flags on the lksb */
 207         lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
 208 }
 209
 210 void dlm_do_local_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 211                       struct dlm_lock *lock)
 212 {
 213         dlm_astlockfunc_t *fn;
 214         struct dlm_lockstatus *lksb;
 215
 216         mlog_entry_void();
 217
 218         lksb = lock->lksb;
 219         fn = lock->ast;
 220         BUG_ON(lock->ml.node != dlm->node_num);
 221
 222         dlm_update_lvb(dlm, res, lock);
 223         (*fn)(lock->astdata);
 224 }
 225
 226
 227 int dlm_do_remote_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 228                       struct dlm_lock *lock)
 229 {
 230         int ret;
 231         struct dlm_lockstatus *lksb;
 232         int lksbflags;
 233
 234         mlog_entry_void();
 235
 236         lksb = lock->lksb;
 237         BUG_ON(lock->ml.node == dlm->node_num);
 238
 239         lksbflags = lksb->flags;
 240         dlm_update_lvb(dlm, res, lock);
 241
 242         /* lock request came from another node
 243          * go do the ast over there */
 244         ret = dlm_send_proxy_ast(dlm, res, lock, lksbflags);
 245         return ret;
 246 }
 247
 248 void dlm_do_local_bast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 249                        struct dlm_lock *lock, int blocked_type)
 250 {
 251         dlm_bastlockfunc_t *fn = lock->bast;
 252
 253         mlog_entry_void();
 254         BUG_ON(lock->ml.node != dlm->node_num);
 255
 256         (*fn)(lock->astdata, blocked_type);
 257 }
 258
 259
 260
 261 int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *data,
 262                           void **ret_data)
 263 {
 264         int ret;
 265         unsigned int locklen;
 266         struct dlm_ctxt *dlm = data;
 267         struct dlm_lock_resource *res = NULL;
 268         struct dlm_lock *lock = NULL;
 269         struct dlm_proxy_ast *past = (struct dlm_proxy_ast *) msg->buf;
 270         char *name;
 271         struct list_head *iter, *head=NULL;
 272         u64 cookie;
 273         u32 flags;
 274         u8 node;
 275
 276         if (!dlm_grab(dlm)) {
 277                 dlm_error(DLM_REJECTED);
 278                 return DLM_REJECTED;
 279         }
 280
 281         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
 282                         "Domain %s not fully joined!\n", dlm->name);
 283
 284         name = past->name;
 285         locklen = past->namelen;
 286         cookie = past->cookie;
 287         flags = be32_to_cpu(past->flags);
 288         node = past->node_idx;
 289
 290         if (locklen > DLM_LOCKID_NAME_MAX) {
 291                 ret = DLM_IVBUFLEN;
 292                 mlog(ML_ERROR, "Invalid name length (%d) in proxy ast "
 293                      "handler!\n", locklen);
 294                 goto leave;
 295         }
 296
 297         if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
 298              (LKM_PUT_LVB|LKM_GET_LVB)) {
 299                 mlog(ML_ERROR, "Both PUT and GET lvb specified, (0x%x)\n",
 300                      flags);
 301                 ret = DLM_BADARGS;
 302                 goto leave;
 303         }
 304
 305         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
 306                   (flags & LKM_GET_LVB ? "get lvb" : "none"));
 307
 308         mlog(0, "type=%d, blocked_type=%d\n", past->type, past->blocked_type);
 309
 310         if (past->type != DLM_AST &&
 311             past->type != DLM_BAST) {
 312                 mlog(ML_ERROR, "Unknown ast type! %d, cookie=%u:%llu"
 313                      "name=%.*s, node=%u\n", past->type,
 314                      dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
 315                      dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
 316                      locklen, name, node);
 317                 ret = DLM_IVLOCKID;
 318                 goto leave;
 319         }
 320
 321         res = dlm_lookup_lockres(dlm, name, locklen);
 322         if (!res) {
 323                 mlog(0, "Got %sast for unknown lockres! cookie=%u:%llu, "
 324                      "name=%.*s, node=%u\n", (past->type == DLM_AST ? "" : "b"),
 325                      dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
 326                      dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
 327                      locklen, name, node);
 328                 ret = DLM_IVLOCKID;
 329                 goto leave;
 330         }
 331
 332         /* cannot get a proxy ast message if this node owns it */
 333         BUG_ON(res->owner == dlm->node_num);
 334
 335         mlog(0, "lockres %.*s\n", res->lockname.len, res->lockname.name);
 336
 337         spin_lock(&res->spinlock);
 338         if (res->state & DLM_LOCK_RES_RECOVERING) {
 339                 mlog(0, "Responding with DLM_RECOVERING!\n");
 340                 ret = DLM_RECOVERING;
 341                 goto unlock_out;
 342         }
 343         if (res->state & DLM_LOCK_RES_MIGRATING) {
 344                 mlog(0, "Responding with DLM_MIGRATING!\n");
 345                 ret = DLM_MIGRATING;
 346                 goto unlock_out;
 347         }
 348         /* try convert queue for both ast/bast */
 349         head = &res->converting;
 350         lock = NULL;
 351         list_for_each(iter, head) {
 352                 lock = list_entry (iter, struct dlm_lock, list);
 353                 if (lock->ml.cookie == cookie)
 354                         goto do_ast;
 355         }
 356
 357         /* if not on convert, try blocked for ast, granted for bast */
 358         if (past->type == DLM_AST)
 359                 head = &res->blocked;
 360         else
 361                 head = &res->granted;
 362
 363         list_for_each(iter, head) {
 364                 lock = list_entry (iter, struct dlm_lock, list);
 365                 if (lock->ml.cookie == cookie)
 366                         goto do_ast;
 367         }
 368
 369         mlog(0, "Got %sast for unknown lock! cookie=%u:%llu, name=%.*s, "
 370              "node=%u\n", past->type == DLM_AST ? "" : "b",
 371              dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
 372              dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
 373              locklen, name, node);
 374
 375         ret = DLM_NORMAL;
 376 unlock_out:
 377         spin_unlock(&res->spinlock);
 378         goto leave;
 379
 380 do_ast:
 381         ret = DLM_NORMAL;
 382         if (past->type == DLM_AST) {
 383                 /* do not alter lock refcount.  switching lists. */
 384                 list_move_tail(&lock->list, &res->granted);
 385                 mlog(0, "ast: Adding to granted list... type=%d, "
 386                      "convert_type=%d\n", lock->ml.type, lock->ml.convert_type);
 387                 if (lock->ml.convert_type != LKM_IVMODE) {
 388                         lock->ml.type = lock->ml.convert_type;
 389                         lock->ml.convert_type = LKM_IVMODE;
 390                 } else {
 391                         // should already be there....
 392                 }
 393
 394                 lock->lksb->status = DLM_NORMAL;
 395
 396                 /* if we requested the lvb, fetch it into our lksb now */
 397                 if (flags & LKM_GET_LVB) {
 398                         BUG_ON(!(lock->lksb->flags & DLM_LKSB_GET_LVB));
 399                         memcpy(lock->lksb->lvb, past->lvb, DLM_LVB_LEN);
 400                 }
 401         }
 402         spin_unlock(&res->spinlock);
 403
 404         if (past->type == DLM_AST)
 405                 dlm_do_local_ast(dlm, res, lock);
 406         else
 407                 dlm_do_local_bast(dlm, res, lock, past->blocked_type);
 408
 409 leave:
 410         if (res)
 411                 dlm_lockres_put(res);
 412
 413         dlm_put(dlm);
 414         return ret;
 415 }
 416
 417
 418
 419 int dlm_send_proxy_ast_msg(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 420                            struct dlm_lock *lock, int msg_type,
 421                            int blocked_type, int flags)
 422 {
 423         int ret = 0;
 424         struct dlm_proxy_ast past;
 425         struct kvec vec[2];
 426         size_t veclen = 1;
 427         int status;
 428
 429         mlog_entry("res %.*s, to=%u, type=%d, blocked_type=%d\n",
 430                    res->lockname.len, res->lockname.name, lock->ml.node,
 431                    msg_type, blocked_type);
 432
 433         memset(&past, 0, sizeof(struct dlm_proxy_ast));
 434         past.node_idx = dlm->node_num;
 435         past.type = msg_type;
 436         past.blocked_type = blocked_type;
 437         past.namelen = res->lockname.len;
 438         memcpy(past.name, res->lockname.name, past.namelen);
 439         past.cookie = lock->ml.cookie;
 440
 441         vec[0].iov_len = sizeof(struct dlm_proxy_ast);
 442         vec[0].iov_base = &past;
 443         if (flags & DLM_LKSB_GET_LVB) {
 444                 mlog(0, "returning requested LVB data\n");
 445                 be32_add_cpu(&past.flags, LKM_GET_LVB);
 446                 vec[1].iov_len = DLM_LVB_LEN;
 447                 vec[1].iov_base = lock->lksb->lvb;
 448                 veclen++;
 449         }
 450
 451         ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
 452                                      lock->ml.node, &status);
 453         if (ret < 0)
 454                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
 455                      "node %u\n", ret, DLM_PROXY_AST_MSG, dlm->key,
 456                      lock->ml.node);
 457         else {
 458                 if (status == DLM_RECOVERING) {
 459                         mlog(ML_ERROR, "sent AST to node %u, it thinks this "
 460                              "node is dead!\n", lock->ml.node);
 461                         BUG();
 462                 } else if (status == DLM_MIGRATING) {
 463                         mlog(ML_ERROR, "sent AST to node %u, it returned "
 464                              "DLM_MIGRATING!\n", lock->ml.node);
 465                         BUG();
 466                 } else if (status != DLM_NORMAL && status != DLM_IVLOCKID) {
 467                         mlog(ML_ERROR, "AST to node %u returned %d!\n",
 468                              lock->ml.node, status);
 469                         /* ignore it */
 470                 }
 471                 ret = 0;
 472         }
 473         return ret;
 474 }