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         if (lock->ast_pending)
 107                 mlog(0, "lock has an ast getting flushed right now\n");
 108
 109         /* putting lock on list, add a ref */
 110         dlm_lock_get(lock);
 111         spin_lock(&lock->spinlock);
 112
 113         /* check to see if this ast obsoletes the bast */
 114         if (dlm_should_cancel_bast(dlm, lock)) {
 115                 struct dlm_lock_resource *res = lock->lockres;
 116                 mlog(0, "%s: cancelling bast for %.*s\n",
 117                      dlm->name, res->lockname.len, res->lockname.name);
 118                 lock->bast_pending = 0;
 119                 list_del_init(&lock->bast_list);
 120                 lock->ml.highest_blocked = LKM_IVMODE;
 121                 /* removing lock from list, remove a ref.  guaranteed
 122                  * this won't be the last ref because of the get above,
 123                  * so res->spinlock will not be taken here */
 124                 dlm_lock_put(lock);
 125                 /* free up the reserved bast that we are cancelling.
 126                  * guaranteed that this will not be the last reserved
 127                  * ast because *both* an ast and a bast were reserved
 128                  * to get to this point.  the res->spinlock will not be
 129                  * taken here */
 130                 dlm_lockres_release_ast(dlm, res);
 131         }
 132         list_add_tail(&lock->ast_list, &dlm->pending_asts);
 133         lock->ast_pending = 1;
 134         spin_unlock(&lock->spinlock);
 135 }
 136
 137 void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 138 {
 139         mlog_entry_void();
 140
 141         BUG_ON(!dlm);
 142         BUG_ON(!lock);
 143
 144         spin_lock(&dlm->ast_lock);
 145         __dlm_queue_ast(dlm, lock);
 146         spin_unlock(&dlm->ast_lock);
 147 }
 148
 149
 150 static void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 151 {
 152         mlog_entry_void();
 153
 154         BUG_ON(!dlm);
 155         BUG_ON(!lock);
 156         assert_spin_locked(&dlm->ast_lock);
 157
 158         BUG_ON(!list_empty(&lock->bast_list));
 159         if (lock->bast_pending)
 160                 mlog(0, "lock has a bast getting flushed right now\n");
 161
 162         /* putting lock on list, add a ref */
 163         dlm_lock_get(lock);
 164         spin_lock(&lock->spinlock);
 165         list_add_tail(&lock->bast_list, &dlm->pending_basts);
 166         lock->bast_pending = 1;
 167         spin_unlock(&lock->spinlock);
 168 }
 169
 170 void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 171 {
 172         mlog_entry_void();
 173
 174         BUG_ON(!dlm);
 175         BUG_ON(!lock);
 176
 177         spin_lock(&dlm->ast_lock);
 178         __dlm_queue_bast(dlm, lock);
 179         spin_unlock(&dlm->ast_lock);
 180 }
 181
 182 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 183                            struct dlm_lock *lock)
 184 {
 185         struct dlm_lockstatus *lksb = lock->lksb;
 186         BUG_ON(!lksb);
 187
 188         /* only updates if this node masters the lockres */
 189         if (res->owner == dlm->node_num) {
 190
 191                 spin_lock(&res->spinlock);
 192                 /* check the lksb flags for the direction */
 193                 if (lksb->flags & DLM_LKSB_GET_LVB) {
 194                         mlog(0, "getting lvb from lockres for %s node\n",
 195                                   lock->ml.node == dlm->node_num ? "master" :
 196                                   "remote");
 197                         memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
 198                 }
 199                 /* Do nothing for lvb put requests - they should be done in
 200                  * place when the lock is downconverted - otherwise we risk
 201                  * racing gets and puts which could result in old lvb data
 202                  * being propagated. We leave the put flag set and clear it
 203                  * here. In the future we might want to clear it at the time
 204                  * the put is actually done.
 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                           void **ret_data)
 266 {
 267         int ret;
 268         unsigned int locklen;
 269         struct dlm_ctxt *dlm = data;
 270         struct dlm_lock_resource *res = NULL;
 271         struct dlm_lock *lock = NULL;
 272         struct dlm_proxy_ast *past = (struct dlm_proxy_ast *) msg->buf;
 273         char *name;
 274         struct list_head *iter, *head=NULL;
 275         u64 cookie;
 276         u32 flags;
 277         u8 node;
 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 = past->cookie;
 290         flags = be32_to_cpu(past->flags);
 291         node = past->node_idx;
 292
 293         if (locklen > DLM_LOCKID_NAME_MAX) {
 294                 ret = DLM_IVBUFLEN;
 295                 mlog(ML_ERROR, "Invalid name length (%d) in proxy ast "
 296                      "handler!\n", locklen);
 297                 goto leave;
 298         }
 299
 300         if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
 301              (LKM_PUT_LVB|LKM_GET_LVB)) {
 302                 mlog(ML_ERROR, "Both PUT and GET lvb specified, (0x%x)\n",
 303                      flags);
 304                 ret = DLM_BADARGS;
 305                 goto leave;
 306         }
 307
 308         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
 309                   (flags & LKM_GET_LVB ? "get lvb" : "none"));
 310
 311         mlog(0, "type=%d, blocked_type=%d\n", past->type, past->blocked_type);
 312
 313         if (past->type != DLM_AST &&
 314             past->type != DLM_BAST) {
 315                 mlog(ML_ERROR, "Unknown ast type! %d, cookie=%u:%llu"
 316                      "name=%.*s, node=%u\n", past->type,
 317                      dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
 318                      dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
 319                      locklen, name, node);
 320                 ret = DLM_IVLOCKID;
 321                 goto leave;
 322         }
 323
 324         res = dlm_lookup_lockres(dlm, name, locklen);
 325         if (!res) {
 326                 mlog(0, "Got %sast for unknown lockres! cookie=%u:%llu, "
 327                      "name=%.*s, node=%u\n", (past->type == DLM_AST ? "" : "b"),
 328                      dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
 329                      dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
 330                      locklen, name, node);
 331                 ret = DLM_IVLOCKID;
 332                 goto leave;
 333         }
 334
 335         /* cannot get a proxy ast message if this node owns it */
 336         BUG_ON(res->owner == dlm->node_num);
 337
 338         mlog(0, "lockres %.*s\n", res->lockname.len, res->lockname.name);
 339
 340         spin_lock(&res->spinlock);
 341         if (res->state & DLM_LOCK_RES_RECOVERING) {
 342                 mlog(0, "Responding with DLM_RECOVERING!\n");
 343                 ret = DLM_RECOVERING;
 344                 goto unlock_out;
 345         }
 346         if (res->state & DLM_LOCK_RES_MIGRATING) {
 347                 mlog(0, "Responding with DLM_MIGRATING!\n");
 348                 ret = DLM_MIGRATING;
 349                 goto unlock_out;
 350         }
 351         /* try convert queue for both ast/bast */
 352         head = &res->converting;
 353         lock = NULL;
 354         list_for_each(iter, head) {
 355                 lock = list_entry (iter, struct dlm_lock, list);
 356                 if (lock->ml.cookie == cookie)
 357                         goto do_ast;
 358         }
 359
 360         /* if not on convert, try blocked for ast, granted for bast */
 361         if (past->type == DLM_AST)
 362                 head = &res->blocked;
 363         else
 364                 head = &res->granted;
 365
 366         list_for_each(iter, head) {
 367                 lock = list_entry (iter, struct dlm_lock, list);
 368                 if (lock->ml.cookie == cookie)
 369                         goto do_ast;
 370         }
 371
 372         mlog(0, "Got %sast for unknown lock! cookie=%u:%llu, name=%.*s, "
 373              "node=%u\n", past->type == DLM_AST ? "" : "b",
 374              dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
 375              dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
 376              locklen, name, node);
 377
 378         ret = DLM_NORMAL;
 379 unlock_out:
 380         spin_unlock(&res->spinlock);
 381         goto leave;
 382
 383 do_ast:
 384         ret = DLM_NORMAL;
 385         if (past->type == DLM_AST) {
 386                 /* do not alter lock refcount.  switching lists. */
 387                 list_move_tail(&lock->list, &res->granted);
 388                 mlog(0, "ast: Adding to granted list... type=%d, "
 389                      "convert_type=%d\n", lock->ml.type, lock->ml.convert_type);
 390                 if (lock->ml.convert_type != LKM_IVMODE) {
 391                         lock->ml.type = lock->ml.convert_type;
 392                         lock->ml.convert_type = LKM_IVMODE;
 393                 } else {
 394                         // should already be there....
 395                 }
 396
 397                 lock->lksb->status = DLM_NORMAL;
 398
 399                 /* if we requested the lvb, fetch it into our lksb now */
 400                 if (flags & LKM_GET_LVB) {
 401                         BUG_ON(!(lock->lksb->flags & DLM_LKSB_GET_LVB));
 402                         memcpy(lock->lksb->lvb, past->lvb, DLM_LVB_LEN);
 403                 }
 404         }
 405         spin_unlock(&res->spinlock);
 406
 407         if (past->type == DLM_AST)
 408                 dlm_do_local_ast(dlm, res, lock);
 409         else
 410                 dlm_do_local_bast(dlm, res, lock, past->blocked_type);
 411
 412 leave:
 413         if (res)
 414                 dlm_lockres_put(res);
 415
 416         dlm_put(dlm);
 417         return ret;
 418 }
 419
 420
 421
 422 int dlm_send_proxy_ast_msg(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 423                            struct dlm_lock *lock, int msg_type,
 424                            int blocked_type, int flags)
 425 {
 426         int ret = 0;
 427         struct dlm_proxy_ast past;
 428         struct kvec vec[2];
 429         size_t veclen = 1;
 430         int status;
 431
 432         mlog_entry("res %.*s, to=%u, type=%d, blocked_type=%d\n",
 433                    res->lockname.len, res->lockname.name, lock->ml.node,
 434                    msg_type, blocked_type);
 435
 436         memset(&past, 0, sizeof(struct dlm_proxy_ast));
 437         past.node_idx = dlm->node_num;
 438         past.type = msg_type;
 439         past.blocked_type = blocked_type;
 440         past.namelen = res->lockname.len;
 441         memcpy(past.name, res->lockname.name, past.namelen);
 442         past.cookie = lock->ml.cookie;
 443
 444         vec[0].iov_len = sizeof(struct dlm_proxy_ast);
 445         vec[0].iov_base = &past;
 446         if (flags & DLM_LKSB_GET_LVB) {
 447                 mlog(0, "returning requested LVB data\n");
 448                 be32_add_cpu(&past.flags, LKM_GET_LVB);
 449                 vec[1].iov_len = DLM_LVB_LEN;
 450                 vec[1].iov_base = lock->lksb->lvb;
 451                 veclen++;
 452         }
 453
 454         ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
 455                                      lock->ml.node, &status);
 456         if (ret < 0)
 457                 mlog_errno(ret);
 458         else {
 459                 if (status == DLM_RECOVERING) {
 460                         mlog(ML_ERROR, "sent AST to node %u, it thinks this "
 461                              "node is dead!\n", lock->ml.node);
 462                         BUG();
 463                 } else if (status == DLM_MIGRATING) {
 464                         mlog(ML_ERROR, "sent AST to node %u, it returned "
 465                              "DLM_MIGRATING!\n", lock->ml.node);
 466                         BUG();
 467                 } else if (status != DLM_NORMAL && status != DLM_IVLOCKID) {
 468                         mlog(ML_ERROR, "AST to node %u returned %d!\n",
 469                              lock->ml.node, status);
 470                         /* ignore it */
 471                 }
 472                 ret = 0;
 473         }
 474         return ret;
 475 }