release/src-rt-6.x/linux/linux-2.6/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/slab.h>
  32 #include <linux/highmem.h>
  33 #include <linux/utsname.h>
  34 #include <linux/init.h>
  35 #include <linux/sysctl.h>
  36 #include <linux/random.h>
  37 #include <linux/blkdev.h>
  38 #include <linux/socket.h>
  39 #include <linux/inet.h>
  40 #include <linux/spinlock.h>
  41
  42
  43 #include "cluster/heartbeat.h"
  44 #include "cluster/nodemanager.h"
  45 #include "cluster/tcp.h"
  46
  47 #include "dlmapi.h"
  48 #include "dlmcommon.h"
  49
  50 #define MLOG_MASK_PREFIX ML_DLM
  51 #include "cluster/masklog.h"
  52
  53 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
  54                            struct dlm_lock *lock);
  55 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
  56
  57 /* Should be called as an ast gets queued to see if the new
  58  * lock level will obsolete a pending bast.
  59  * For example, if dlm_thread queued a bast for an EX lock that
  60  * was blocking another EX, but before sending the bast the
  61  * lock owner downconverted to NL, the bast is now obsolete.
  62  * Only the ast should be sent.
  63  * This is needed because the lock and convert paths can queue
  64  * asts out-of-band (not waiting for dlm_thread) in order to
  65  * allow for LKM_NOQUEUE to get immediate responses. */
  66 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
  67 {
  68         assert_spin_locked(&dlm->ast_lock);
  69         assert_spin_locked(&lock->spinlock);
  70
  71         if (lock->ml.highest_blocked == LKM_IVMODE)
  72                 return 0;
  73         BUG_ON(lock->ml.highest_blocked == LKM_NLMODE);
  74
  75         if (lock->bast_pending &&
  76             list_empty(&lock->bast_list))
  77                 /* old bast already sent, ok */
  78                 return 0;
  79
  80         if (lock->ml.type == LKM_EXMODE)
  81                 /* EX blocks anything left, any bast still valid */
  82                 return 0;
  83         else if (lock->ml.type == LKM_NLMODE)
  84                 /* NL blocks nothing, no reason to send any bast, cancel it */
  85                 return 1;
  86         else if (lock->ml.highest_blocked != LKM_EXMODE)
  87                 /* PR only blocks EX */
  88                 return 1;
  89
  90         return 0;
  91 }
  92
  93 static void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
  94 {
  95         mlog_entry_void();
  96
  97         BUG_ON(!dlm);
  98         BUG_ON(!lock);
  99
 100         assert_spin_locked(&dlm->ast_lock);
 101         if (!list_empty(&lock->ast_list)) {
 102                 mlog(ML_ERROR, "ast list not empty!!  pending=%d, newlevel=%d\n",
 103                      lock->ast_pending, lock->ml.type);
 104                 BUG();
 105         }
 106         BUG_ON(!list_empty(&lock->ast_list));
 107         if (lock->ast_pending)
 108                 mlog(0, "lock has an ast getting flushed right now\n");
 109
 110         /* putting lock on list, add a ref */
 111         dlm_lock_get(lock);
 112         spin_lock(&lock->spinlock);
 113
 114         /* check to see if this ast obsoletes the bast */
 115         if (dlm_should_cancel_bast(dlm, lock)) {
 116                 struct dlm_lock_resource *res = lock->lockres;
 117                 mlog(0, "%s: cancelling bast for %.*s\n",
 118                      dlm->name, res->lockname.len, res->lockname.name);
 119                 lock->bast_pending = 0;
 120                 list_del_init(&lock->bast_list);
 121                 lock->ml.highest_blocked = LKM_IVMODE;
 122                 /* removing lock from list, remove a ref.  guaranteed
 123                  * this won't be the last ref because of the get above,
 124                  * so res->spinlock will not be taken here */
 125                 dlm_lock_put(lock);
 126                 /* free up the reserved bast that we are cancelling.
 127                  * guaranteed that this will not be the last reserved
 128                  * ast because *both* an ast and a bast were reserved
 129                  * to get to this point.  the res->spinlock will not be
 130                  * taken here */
 131                 dlm_lockres_release_ast(dlm, res);
 132         }
 133         list_add_tail(&lock->ast_list, &dlm->pending_asts);
 134         lock->ast_pending = 1;
 135         spin_unlock(&lock->spinlock);
 136 }
 137
 138 void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 139 {
 140         mlog_entry_void();
 141
 142         BUG_ON(!dlm);
 143         BUG_ON(!lock);
 144
 145         spin_lock(&dlm->ast_lock);
 146         __dlm_queue_ast(dlm, lock);
 147         spin_unlock(&dlm->ast_lock);
 148 }
 149
 150
 151 static void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 152 {
 153         mlog_entry_void();
 154
 155         BUG_ON(!dlm);
 156         BUG_ON(!lock);
 157         assert_spin_locked(&dlm->ast_lock);
 158
 159         BUG_ON(!list_empty(&lock->bast_list));
 160         if (lock->bast_pending)
 161                 mlog(0, "lock has a bast getting flushed right now\n");
 162
 163         /* putting lock on list, add a ref */
 164         dlm_lock_get(lock);
 165         spin_lock(&lock->spinlock);
 166         list_add_tail(&lock->bast_list, &dlm->pending_basts);
 167         lock->bast_pending = 1;
 168         spin_unlock(&lock->spinlock);
 169 }
 170
 171 void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 172 {
 173         mlog_entry_void();
 174
 175         BUG_ON(!dlm);
 176         BUG_ON(!lock);
 177
 178         spin_lock(&dlm->ast_lock);
 179         __dlm_queue_bast(dlm, lock);
 180         spin_unlock(&dlm->ast_lock);
 181 }
 182
 183 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 184                            struct dlm_lock *lock)
 185 {
 186         struct dlm_lockstatus *lksb = lock->lksb;
 187         BUG_ON(!lksb);
 188
 189         /* only updates if this node masters the lockres */
 190         if (res->owner == dlm->node_num) {
 191
 192                 spin_lock(&res->spinlock);
 193                 /* check the lksb flags for the direction */
 194                 if (lksb->flags & DLM_LKSB_GET_LVB) {
 195                         mlog(0, "getting lvb from lockres for %s node\n",
 196                                   lock->ml.node == dlm->node_num ? "master" :
 197                                   "remote");
 198                         memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
 199                 }
 200                 /* Do nothing for lvb put requests - they should be done in
 201                  * place when the lock is downconverted - otherwise we risk
 202                  * racing gets and puts which could result in old lvb data
 203                  * being propagated. We leave the put flag set and clear it
 204                  * here. In the future we might want to clear it at the time
 205                  * the put is actually done.
 206                  */
 207                 spin_unlock(&res->spinlock);
 208         }
 209
 210         /* reset any lvb flags on the lksb */
 211         lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
 212 }
 213
 214 void dlm_do_local_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 215                       struct dlm_lock *lock)
 216 {
 217         dlm_astlockfunc_t *fn;
 218         struct dlm_lockstatus *lksb;
 219
 220         mlog_entry_void();
 221
 222         lksb = lock->lksb;
 223         fn = lock->ast;
 224         BUG_ON(lock->ml.node != dlm->node_num);
 225
 226         dlm_update_lvb(dlm, res, lock);
 227         (*fn)(lock->astdata);
 228 }
 229
 230
 231 int dlm_do_remote_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 232                       struct dlm_lock *lock)
 233 {
 234         int ret;
 235         struct dlm_lockstatus *lksb;
 236         int lksbflags;
 237
 238         mlog_entry_void();
 239
 240         lksb = lock->lksb;
 241         BUG_ON(lock->ml.node == dlm->node_num);
 242
 243         lksbflags = lksb->flags;
 244         dlm_update_lvb(dlm, res, lock);
 245
 246         /* lock request came from another node
 247          * go do the ast over there */
 248         ret = dlm_send_proxy_ast(dlm, res, lock, lksbflags);
 249         return ret;
 250 }
 251
 252 void dlm_do_local_bast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 253                        struct dlm_lock *lock, int blocked_type)
 254 {
 255         dlm_bastlockfunc_t *fn = lock->bast;
 256
 257         mlog_entry_void();
 258         BUG_ON(lock->ml.node != dlm->node_num);
 259
 260         (*fn)(lock->astdata, blocked_type);
 261 }
 262
 263
 264
 265 int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *data,
 266                           void **ret_data)
 267 {
 268         int ret;
 269         unsigned int locklen;
 270         struct dlm_ctxt *dlm = data;
 271         struct dlm_lock_resource *res = NULL;
 272         struct dlm_lock *lock = NULL;
 273         struct dlm_proxy_ast *past = (struct dlm_proxy_ast *) msg->buf;
 274         char *name;
 275         struct list_head *iter, *head=NULL;
 276         u64 cookie;
 277         u32 flags;
 278
 279         if (!dlm_grab(dlm)) {
 280                 dlm_error(DLM_REJECTED);
 281                 return DLM_REJECTED;
 282         }
 283
 284         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
 285                         "Domain %s not fully joined!\n", dlm->name);
 286
 287         name = past->name;
 288         locklen = past->namelen;
 289         cookie = be64_to_cpu(past->cookie);
 290         flags = be32_to_cpu(past->flags);
 291
 292         if (locklen > DLM_LOCKID_NAME_MAX) {
 293                 ret = DLM_IVBUFLEN;
 294                 mlog(ML_ERROR, "Invalid name length in proxy ast handler!\n");
 295                 goto leave;
 296         }
 297
 298         if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
 299              (LKM_PUT_LVB|LKM_GET_LVB)) {
 300                 mlog(ML_ERROR, "both PUT and GET lvb specified\n");
 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\n", past->type,
 314                      dlm_get_lock_cookie_node(cookie),
 315                      dlm_get_lock_cookie_seq(cookie),
 316                      locklen, name);
 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! "
 324                      "cookie=%u:%llu, name=%.*s, namelen=%u\n",
 325                      past->type == DLM_AST ? "" : "b",
 326                      dlm_get_lock_cookie_node(cookie),
 327                      dlm_get_lock_cookie_seq(cookie),
 328                      locklen, name, locklen);
 329                 ret = DLM_IVLOCKID;
 330                 goto leave;
 331         }
 332
 333         /* cannot get a proxy ast message if this node owns it */
 334         BUG_ON(res->owner == dlm->node_num);
 335
 336         mlog(0, "lockres %.*s\n", res->lockname.len, res->lockname.name);
 337
 338         spin_lock(&res->spinlock);
 339         if (res->state & DLM_LOCK_RES_RECOVERING) {
 340                 mlog(0, "responding with DLM_RECOVERING!\n");
 341                 ret = DLM_RECOVERING;
 342                 goto unlock_out;
 343         }
 344         if (res->state & DLM_LOCK_RES_MIGRATING) {
 345                 mlog(0, "responding with DLM_MIGRATING!\n");
 346                 ret = DLM_MIGRATING;
 347                 goto unlock_out;
 348         }
 349         /* try convert queue for both ast/bast */
 350         head = &res->converting;
 351         lock = NULL;
 352         list_for_each(iter, head) {
 353                 lock = list_entry (iter, struct dlm_lock, list);
 354                 if (be64_to_cpu(lock->ml.cookie) == cookie)
 355                         goto do_ast;
 356         }
 357
 358         /* if not on convert, try blocked for ast, granted for bast */
 359         if (past->type == DLM_AST)
 360                 head = &res->blocked;
 361         else
 362                 head = &res->granted;
 363
 364         list_for_each(iter, head) {
 365                 lock = list_entry (iter, struct dlm_lock, list);
 366                 if (be64_to_cpu(lock->ml.cookie) == cookie)
 367                         goto do_ast;
 368         }
 369
 370         mlog(0, "got %sast for unknown lock!  cookie=%u:%llu, "
 371              "name=%.*s, namelen=%u\n", past->type == DLM_AST ? "" : "b",
 372              dlm_get_lock_cookie_node(cookie),
 373              dlm_get_lock_cookie_seq(cookie),
 374              locklen, name, locklen);
 375
 376         ret = DLM_NORMAL;
 377 unlock_out:
 378         spin_unlock(&res->spinlock);
 379         goto leave;
 380
 381 do_ast:
 382         ret = DLM_NORMAL;
 383         if (past->type == DLM_AST) {
 384                 /* do not alter lock refcount.  switching lists. */
 385                 list_move_tail(&lock->list, &res->granted);
 386                 mlog(0, "ast: adding to granted list... type=%d, "
 387                           "convert_type=%d\n", lock->ml.type, lock->ml.convert_type);
 388                 if (lock->ml.convert_type != LKM_IVMODE) {
 389                         lock->ml.type = lock->ml.convert_type;
 390                         lock->ml.convert_type = LKM_IVMODE;
 391                 } else {
 392                         // should already be there....
 393                 }
 394
 395                 lock->lksb->status = DLM_NORMAL;
 396
 397                 /* if we requested the lvb, fetch it into our lksb now */
 398                 if (flags & LKM_GET_LVB) {
 399                         BUG_ON(!(lock->lksb->flags & DLM_LKSB_GET_LVB));
 400                         memcpy(lock->lksb->lvb, past->lvb, DLM_LVB_LEN);
 401                 }
 402         }
 403         spin_unlock(&res->spinlock);
 404
 405         if (past->type == DLM_AST)
 406                 dlm_do_local_ast(dlm, res, lock);
 407         else
 408                 dlm_do_local_bast(dlm, res, lock, past->blocked_type);
 409
 410 leave:
 411
 412         if (res)
 413                 dlm_lockres_put(res);
 414
 415         dlm_put(dlm);
 416         return ret;
 417 }
 418
 419
 420
 421 int dlm_send_proxy_ast_msg(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 422                            struct dlm_lock *lock, int msg_type,
 423                            int blocked_type, int flags)
 424 {
 425         int ret = 0;
 426         struct dlm_proxy_ast past;
 427         struct kvec vec[2];
 428         size_t veclen = 1;
 429         int status;
 430
 431         mlog_entry("res %.*s, to=%u, type=%d, blocked_type=%d\n",
 432                    res->lockname.len, res->lockname.name, lock->ml.node,
 433                    msg_type, blocked_type);
 434
 435         memset(&past, 0, sizeof(struct dlm_proxy_ast));
 436         past.node_idx = dlm->node_num;
 437         past.type = msg_type;
 438         past.blocked_type = blocked_type;
 439         past.namelen = res->lockname.len;
 440         memcpy(past.name, res->lockname.name, past.namelen);
 441         past.cookie = lock->ml.cookie;
 442
 443         vec[0].iov_len = sizeof(struct dlm_proxy_ast);
 444         vec[0].iov_base = &past;
 445         if (flags & DLM_LKSB_GET_LVB) {
 446                 mlog(0, "returning requested LVB data\n");
 447                 be32_add_cpu(&past.flags, LKM_GET_LVB);
 448                 vec[1].iov_len = DLM_LVB_LEN;
 449                 vec[1].iov_base = lock->lksb->lvb;
 450                 veclen++;
 451         }
 452
 453         ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
 454                                      lock->ml.node, &status);
 455         if (ret < 0)
 456                 mlog_errno(ret);
 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 }