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 #include "cluster/endian.h"
  47
  48 #include "dlmapi.h"
  49 #include "dlmcommon.h"
  50
  51 #define MLOG_MASK_PREFIX ML_DLM
  52 #include "cluster/masklog.h"
  53
  54 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
  55                            struct dlm_lock *lock);
  56 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
  57
  58 /* Should be called as an ast gets queued to see if the new
  59  * lock level will obsolete a pending bast.
  60  * For example, if dlm_thread queued a bast for an EX lock that
  61  * was blocking another EX, but before sending the bast the
  62  * lock owner downconverted to NL, the bast is now obsolete.
  63  * Only the ast should be sent.
  64  * This is needed because the lock and convert paths can queue
  65  * asts out-of-band (not waiting for dlm_thread) in order to
  66  * allow for LKM_NOQUEUE to get immediate responses. */
  67 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
  68 {
  69         assert_spin_locked(&dlm->ast_lock);
  70         assert_spin_locked(&lock->spinlock);
  71
  72         if (lock->ml.highest_blocked == LKM_IVMODE)
  73                 return 0;
  74         BUG_ON(lock->ml.highest_blocked == LKM_NLMODE);
  75
  76         if (lock->bast_pending &&
  77             list_empty(&lock->bast_list))
  78                 /* old bast already sent, ok */
  79                 return 0;
  80
  81         if (lock->ml.type == LKM_EXMODE)
  82                 /* EX blocks anything left, any bast still valid */
  83                 return 0;
  84         else if (lock->ml.type == LKM_NLMODE)
  85                 /* NL blocks nothing, no reason to send any bast, cancel it */
  86                 return 1;
  87         else if (lock->ml.highest_blocked != LKM_EXMODE)
  88                 /* PR only blocks EX */
  89                 return 1;
  90
  91         return 0;
  92 }
  93
  94 static void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
  95 {
  96         mlog_entry_void();
  97
  98         BUG_ON(!dlm);
  99         BUG_ON(!lock);
 100
 101         assert_spin_locked(&dlm->ast_lock);
 102         if (!list_empty(&lock->ast_list)) {
 103                 mlog(ML_ERROR, "ast list not empty!!  pending=%d, newlevel=%d\n",
 104                      lock->ast_pending, lock->ml.type);
 105                 BUG();
 106         }
 107         BUG_ON(!list_empty(&lock->ast_list));
 108         if (lock->ast_pending)
 109                 mlog(0, "lock has an ast getting flushed right now\n");
 110
 111         /* putting lock on list, add a ref */
 112         dlm_lock_get(lock);
 113         spin_lock(&lock->spinlock);
 114
 115         /* check to see if this ast obsoletes the bast */
 116         if (dlm_should_cancel_bast(dlm, lock)) {
 117                 struct dlm_lock_resource *res = lock->lockres;
 118                 mlog(0, "%s: cancelling bast for %.*s\n",
 119                      dlm->name, res->lockname.len, res->lockname.name);
 120                 lock->bast_pending = 0;
 121                 list_del_init(&lock->bast_list);
 122                 lock->ml.highest_blocked = LKM_IVMODE;
 123                 /* removing lock from list, remove a ref.  guaranteed
 124                  * this won't be the last ref because of the get above,
 125                  * so res->spinlock will not be taken here */
 126                 dlm_lock_put(lock);
 127                 /* free up the reserved bast that we are cancelling.
 128                  * guaranteed that this will not be the last reserved
 129                  * ast because *both* an ast and a bast were reserved
 130                  * to get to this point.  the res->spinlock will not be
 131                  * taken here */
 132                 dlm_lockres_release_ast(dlm, res);
 133         }
 134         list_add_tail(&lock->ast_list, &dlm->pending_asts);
 135         lock->ast_pending = 1;
 136         spin_unlock(&lock->spinlock);
 137 }
 138
 139 void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 140 {
 141         mlog_entry_void();
 142
 143         BUG_ON(!dlm);
 144         BUG_ON(!lock);
 145
 146         spin_lock(&dlm->ast_lock);
 147         __dlm_queue_ast(dlm, lock);
 148         spin_unlock(&dlm->ast_lock);
 149 }
 150
 151
 152 static void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 153 {
 154         mlog_entry_void();
 155
 156         BUG_ON(!dlm);
 157         BUG_ON(!lock);
 158         assert_spin_locked(&dlm->ast_lock);
 159
 160         BUG_ON(!list_empty(&lock->bast_list));
 161         if (lock->bast_pending)
 162                 mlog(0, "lock has a bast getting flushed right now\n");
 163
 164         /* putting lock on list, add a ref */
 165         dlm_lock_get(lock);
 166         spin_lock(&lock->spinlock);
 167         list_add_tail(&lock->bast_list, &dlm->pending_basts);
 168         lock->bast_pending = 1;
 169         spin_unlock(&lock->spinlock);
 170 }
 171
 172 void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 173 {
 174         mlog_entry_void();
 175
 176         BUG_ON(!dlm);
 177         BUG_ON(!lock);
 178
 179         spin_lock(&dlm->ast_lock);
 180         __dlm_queue_bast(dlm, lock);
 181         spin_unlock(&dlm->ast_lock);
 182 }
 183
 184 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 185                            struct dlm_lock *lock)
 186 {
 187         struct dlm_lockstatus *lksb = lock->lksb;
 188         BUG_ON(!lksb);
 189
 190         /* only updates if this node masters the lockres */
 191         if (res->owner == dlm->node_num) {
 192
 193                 spin_lock(&res->spinlock);
 194                 /* check the lksb flags for the direction */
 195                 if (lksb->flags & DLM_LKSB_GET_LVB) {
 196                         mlog(0, "getting lvb from lockres for %s node\n",
 197                                   lock->ml.node == dlm->node_num ? "master" :
 198                                   "remote");
 199                         memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
 200                 } else if (lksb->flags & DLM_LKSB_PUT_LVB) {
 201                         mlog(0, "setting lvb from lockres for %s node\n",
 202                                   lock->ml.node == dlm->node_num ? "master" :
 203                                   "remote");
 204                         memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
 205                 }
 206                 spin_unlock(&res->spinlock);
 207         }
 208
 209         /* reset any lvb flags on the lksb */
 210         lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
 211 }
 212
 213 void dlm_do_local_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 214                       struct dlm_lock *lock)
 215 {
 216         dlm_astlockfunc_t *fn;
 217         struct dlm_lockstatus *lksb;
 218
 219         mlog_entry_void();
 220
 221         lksb = lock->lksb;
 222         fn = lock->ast;
 223         BUG_ON(lock->ml.node != dlm->node_num);
 224
 225         dlm_update_lvb(dlm, res, lock);
 226         (*fn)(lock->astdata);
 227 }
 228
 229
 230 int dlm_do_remote_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 231                       struct dlm_lock *lock)
 232 {
 233         int ret;
 234         struct dlm_lockstatus *lksb;
 235         int lksbflags;
 236
 237         mlog_entry_void();
 238
 239         lksb = lock->lksb;
 240         BUG_ON(lock->ml.node == dlm->node_num);
 241
 242         lksbflags = lksb->flags;
 243         dlm_update_lvb(dlm, res, lock);
 244
 245         /* lock request came from another node
 246          * go do the ast over there */
 247         ret = dlm_send_proxy_ast(dlm, res, lock, lksbflags);
 248         return ret;
 249 }
 250
 251 void dlm_do_local_bast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 252                        struct dlm_lock *lock, int blocked_type)
 253 {
 254         dlm_bastlockfunc_t *fn = lock->bast;
 255
 256         mlog_entry_void();
 257         BUG_ON(lock->ml.node != dlm->node_num);
 258
 259         (*fn)(lock->astdata, blocked_type);
 260 }
 261
 262
 263
 264 int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *data)
 265 {
 266         int ret;
 267         unsigned int locklen;
 268         struct dlm_ctxt *dlm = data;
 269         struct dlm_lock_resource *res = NULL;
 270         struct dlm_lock *lock = NULL;
 271         struct dlm_proxy_ast *past = (struct dlm_proxy_ast *) msg->buf;
 272         char *name;
 273         struct list_head *iter, *head=NULL;
 274         u64 cookie;
 275         u32 flags;
 276
 277         if (!dlm_grab(dlm)) {
 278                 dlm_error(DLM_REJECTED);
 279                 return DLM_REJECTED;
 280         }
 281
 282         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
 283                         "Domain %s not fully joined!\n", dlm->name);
 284
 285         name = past->name;
 286         locklen = past->namelen;
 287         cookie = be64_to_cpu(past->cookie);
 288         flags = be32_to_cpu(past->flags);
 289
 290         if (locklen > DLM_LOCKID_NAME_MAX) {
 291                 ret = DLM_IVBUFLEN;
 292                 mlog(ML_ERROR, "Invalid name length in proxy ast handler!\n");
 293                 goto leave;
 294         }
 295
 296         if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
 297              (LKM_PUT_LVB|LKM_GET_LVB)) {
 298                 mlog(ML_ERROR, "both PUT and GET lvb specified\n");
 299                 ret = DLM_BADARGS;
 300                 goto leave;
 301         }
 302
 303         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
 304                   (flags & LKM_GET_LVB ? "get lvb" : "none"));
 305
 306         mlog(0, "type=%d, blocked_type=%d\n", past->type, past->blocked_type);
 307
 308         if (past->type != DLM_AST &&
 309             past->type != DLM_BAST) {
 310                 mlog(ML_ERROR, "Unknown ast type! %d, cookie=%"MLFu64", "
 311                      "name=%.*s\n", past->type, cookie, locklen, name);
 312                 ret = DLM_IVLOCKID;
 313                 goto leave;
 314         }
 315
 316         res = dlm_lookup_lockres(dlm, name, locklen);
 317         if (!res) {
 318                 mlog(ML_ERROR, "got %sast for unknown lockres! "
 319                                "cookie=%"MLFu64", name=%.*s, namelen=%u\n",
 320                      past->type == DLM_AST ? "" : "b",
 321                      cookie, locklen, name, locklen);
 322                 ret = DLM_IVLOCKID;
 323                 goto leave;
 324         }
 325
 326         /* cannot get a proxy ast message if this node owns it */
 327         BUG_ON(res->owner == dlm->node_num);
 328
 329         mlog(0, "lockres %.*s\n", res->lockname.len, res->lockname.name);
 330
 331         spin_lock(&res->spinlock);
 332         if (res->state & DLM_LOCK_RES_RECOVERING) {
 333                 mlog(0, "responding with DLM_RECOVERING!\n");
 334                 ret = DLM_RECOVERING;
 335                 goto unlock_out;
 336         }
 337         if (res->state & DLM_LOCK_RES_MIGRATING) {
 338                 mlog(0, "responding with DLM_MIGRATING!\n");
 339                 ret = DLM_MIGRATING;
 340                 goto unlock_out;
 341         }
 342         /* try convert queue for both ast/bast */
 343         head = &res->converting;
 344         lock = NULL;
 345         list_for_each(iter, head) {
 346                 lock = list_entry (iter, struct dlm_lock, list);
 347                 if (be64_to_cpu(lock->ml.cookie) == cookie)
 348                         goto do_ast;
 349         }
 350
 351         /* if not on convert, try blocked for ast, granted for bast */
 352         if (past->type == DLM_AST)
 353                 head = &res->blocked;
 354         else
 355                 head = &res->granted;
 356
 357         list_for_each(iter, head) {
 358                 lock = list_entry (iter, struct dlm_lock, list);
 359                 if (be64_to_cpu(lock->ml.cookie) == cookie)
 360                         goto do_ast;
 361         }
 362
 363         mlog(ML_ERROR, "got %sast for unknown lock!  cookie=%"MLFu64", "
 364                        "name=%.*s, namelen=%u\n",
 365              past->type == DLM_AST ? "" : "b", cookie, locklen, name, locklen);
 366
 367         ret = DLM_NORMAL;
 368 unlock_out:
 369         spin_unlock(&res->spinlock);
 370         goto leave;
 371
 372 do_ast:
 373         ret = DLM_NORMAL;
 374         if (past->type == DLM_AST) {
 375                 /* do not alter lock refcount.  switching lists. */
 376                 list_del_init(&lock->list);
 377                 list_add_tail(&lock->list, &res->granted);
 378                 mlog(0, "ast: adding to granted list... type=%d, "
 379                           "convert_type=%d\n", lock->ml.type, lock->ml.convert_type);
 380                 if (lock->ml.convert_type != LKM_IVMODE) {
 381                         lock->ml.type = lock->ml.convert_type;
 382                         lock->ml.convert_type = LKM_IVMODE;
 383                 } else {
 384                         // should already be there....
 385                 }
 386
 387                 lock->lksb->status = DLM_NORMAL;
 388
 389                 /* if we requested the lvb, fetch it into our lksb now */
 390                 if (flags & LKM_GET_LVB) {
 391                         BUG_ON(!(lock->lksb->flags & DLM_LKSB_GET_LVB));
 392                         memcpy(lock->lksb->lvb, past->lvb, DLM_LVB_LEN);
 393                 }
 394         }
 395         spin_unlock(&res->spinlock);
 396
 397         if (past->type == DLM_AST)
 398                 dlm_do_local_ast(dlm, res, lock);
 399         else
 400                 dlm_do_local_bast(dlm, res, lock, past->blocked_type);
 401
 402 leave:
 403
 404         if (res)
 405                 dlm_lockres_put(res);
 406
 407         dlm_put(dlm);
 408         return ret;
 409 }
 410
 411
 412
 413 int dlm_send_proxy_ast_msg(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 414                            struct dlm_lock *lock, int msg_type,
 415                            int blocked_type, int flags)
 416 {
 417         int ret = 0;
 418         struct dlm_proxy_ast past;
 419         struct kvec vec[2];
 420         size_t veclen = 1;
 421         int status;
 422
 423         mlog_entry("res %.*s, to=%u, type=%d, blocked_type=%d\n",
 424                    res->lockname.len, res->lockname.name, lock->ml.node,
 425                    msg_type, blocked_type);
 426
 427         memset(&past, 0, sizeof(struct dlm_proxy_ast));
 428         past.node_idx = dlm->node_num;
 429         past.type = msg_type;
 430         past.blocked_type = blocked_type;
 431         past.namelen = res->lockname.len;
 432         memcpy(past.name, res->lockname.name, past.namelen);
 433         past.cookie = lock->ml.cookie;
 434
 435         vec[0].iov_len = sizeof(struct dlm_proxy_ast);
 436         vec[0].iov_base = &past;
 437         if (flags & DLM_LKSB_GET_LVB) {
 438                 mlog(0, "returning requested LVB data\n");
 439                 be32_add_cpu(&past.flags, LKM_GET_LVB);
 440                 vec[1].iov_len = DLM_LVB_LEN;
 441                 vec[1].iov_base = lock->lksb->lvb;
 442                 veclen++;
 443         }
 444
 445         ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
 446                                      lock->ml.node, &status);
 447         if (ret < 0)
 448                 mlog_errno(ret);
 449         else {
 450                 if (status == DLM_RECOVERING) {
 451                         mlog(ML_ERROR, "sent AST to node %u, it thinks this "
 452                              "node is dead!\n", lock->ml.node);
 453                         BUG();
 454                 } else if (status == DLM_MIGRATING) {
 455                         mlog(ML_ERROR, "sent AST to node %u, it returned "
 456                              "DLM_MIGRATING!\n", lock->ml.node);
 457                         BUG();
 458                 } else if (status != DLM_NORMAL) {
 459                         mlog(ML_ERROR, "AST to node %u returned %d!\n",
 460                              lock->ml.node, status);
 461                         /* ignore it */
 462                 }
 463                 ret = 0;
 464         }
 465         return ret;
 466 }