[PATCH] OCFS2: The Second Oracle Cluster Filesystem
A distributed lock manager built with the cluster file system use case
in mind. The OCFS2 dlm exposes a VMS style API, though things have
been simplified internally. The only lock levels implemented currently
are NLMODE, PRMODE and EXMODE.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Kurt Hackel <kurt.hackel@oracle.com>
diff --git a/fs/ocfs2/dlm/dlmast.c b/fs/ocfs2/dlm/dlmast.c
new file mode 100644
index 0000000..8d17d28
--- /dev/null
+++ b/fs/ocfs2/dlm/dlmast.c
@@ -0,0 +1,466 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * dlmast.c
+ *
+ * AST and BAST functionality for local and remote nodes
+ *
+ * Copyright (C) 2004 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ *
+ */
+
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/highmem.h>
+#include <linux/utsname.h>
+#include <linux/init.h>
+#include <linux/sysctl.h>
+#include <linux/random.h>
+#include <linux/blkdev.h>
+#include <linux/socket.h>
+#include <linux/inet.h>
+#include <linux/spinlock.h>
+
+
+#include "cluster/heartbeat.h"
+#include "cluster/nodemanager.h"
+#include "cluster/tcp.h"
+#include "cluster/endian.h"
+
+#include "dlmapi.h"
+#include "dlmcommon.h"
+
+#define MLOG_MASK_PREFIX ML_DLM
+#include "cluster/masklog.h"
+
+static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
+ struct dlm_lock *lock);
+static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
+
+/* Should be called as an ast gets queued to see if the new
+ * lock level will obsolete a pending bast.
+ * For example, if dlm_thread queued a bast for an EX lock that
+ * was blocking another EX, but before sending the bast the
+ * lock owner downconverted to NL, the bast is now obsolete.
+ * Only the ast should be sent.
+ * This is needed because the lock and convert paths can queue
+ * asts out-of-band (not waiting for dlm_thread) in order to
+ * allow for LKM_NOQUEUE to get immediate responses. */
+static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
+{
+ assert_spin_locked(&dlm->ast_lock);
+ assert_spin_locked(&lock->spinlock);
+
+ if (lock->ml.highest_blocked == LKM_IVMODE)
+ return 0;
+ BUG_ON(lock->ml.highest_blocked == LKM_NLMODE);
+
+ if (lock->bast_pending &&
+ list_empty(&lock->bast_list))
+ /* old bast already sent, ok */
+ return 0;
+
+ if (lock->ml.type == LKM_EXMODE)
+ /* EX blocks anything left, any bast still valid */
+ return 0;
+ else if (lock->ml.type == LKM_NLMODE)
+ /* NL blocks nothing, no reason to send any bast, cancel it */
+ return 1;
+ else if (lock->ml.highest_blocked != LKM_EXMODE)
+ /* PR only blocks EX */
+ return 1;
+
+ return 0;
+}
+
+static void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
+{
+ mlog_entry_void();
+
+ BUG_ON(!dlm);
+ BUG_ON(!lock);
+
+ assert_spin_locked(&dlm->ast_lock);
+ if (!list_empty(&lock->ast_list)) {
+ mlog(ML_ERROR, "ast list not empty!! pending=%d, newlevel=%d\n",
+ lock->ast_pending, lock->ml.type);
+ BUG();
+ }
+ BUG_ON(!list_empty(&lock->ast_list));
+ if (lock->ast_pending)
+ mlog(0, "lock has an ast getting flushed right now\n");
+
+ /* putting lock on list, add a ref */
+ dlm_lock_get(lock);
+ spin_lock(&lock->spinlock);
+
+ /* check to see if this ast obsoletes the bast */
+ if (dlm_should_cancel_bast(dlm, lock)) {
+ struct dlm_lock_resource *res = lock->lockres;
+ mlog(0, "%s: cancelling bast for %.*s\n",
+ dlm->name, res->lockname.len, res->lockname.name);
+ lock->bast_pending = 0;
+ list_del_init(&lock->bast_list);
+ lock->ml.highest_blocked = LKM_IVMODE;
+ /* removing lock from list, remove a ref. guaranteed
+ * this won't be the last ref because of the get above,
+ * so res->spinlock will not be taken here */
+ dlm_lock_put(lock);
+ /* free up the reserved bast that we are cancelling.
+ * guaranteed that this will not be the last reserved
+ * ast because *both* an ast and a bast were reserved
+ * to get to this point. the res->spinlock will not be
+ * taken here */
+ dlm_lockres_release_ast(dlm, res);
+ }
+ list_add_tail(&lock->ast_list, &dlm->pending_asts);
+ lock->ast_pending = 1;
+ spin_unlock(&lock->spinlock);
+}
+
+void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
+{
+ mlog_entry_void();
+
+ BUG_ON(!dlm);
+ BUG_ON(!lock);
+
+ spin_lock(&dlm->ast_lock);
+ __dlm_queue_ast(dlm, lock);
+ spin_unlock(&dlm->ast_lock);
+}
+
+
+static void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
+{
+ mlog_entry_void();
+
+ BUG_ON(!dlm);
+ BUG_ON(!lock);
+ assert_spin_locked(&dlm->ast_lock);
+
+ BUG_ON(!list_empty(&lock->bast_list));
+ if (lock->bast_pending)
+ mlog(0, "lock has a bast getting flushed right now\n");
+
+ /* putting lock on list, add a ref */
+ dlm_lock_get(lock);
+ spin_lock(&lock->spinlock);
+ list_add_tail(&lock->bast_list, &dlm->pending_basts);
+ lock->bast_pending = 1;
+ spin_unlock(&lock->spinlock);
+}
+
+void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
+{
+ mlog_entry_void();
+
+ BUG_ON(!dlm);
+ BUG_ON(!lock);
+
+ spin_lock(&dlm->ast_lock);
+ __dlm_queue_bast(dlm, lock);
+ spin_unlock(&dlm->ast_lock);
+}
+
+static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
+ struct dlm_lock *lock)
+{
+ struct dlm_lockstatus *lksb = lock->lksb;
+ BUG_ON(!lksb);
+
+ /* only updates if this node masters the lockres */
+ if (res->owner == dlm->node_num) {
+
+ spin_lock(&res->spinlock);
+ /* check the lksb flags for the direction */
+ if (lksb->flags & DLM_LKSB_GET_LVB) {
+ mlog(0, "getting lvb from lockres for %s node\n",
+ lock->ml.node == dlm->node_num ? "master" :
+ "remote");
+ memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
+ } else if (lksb->flags & DLM_LKSB_PUT_LVB) {
+ mlog(0, "setting lvb from lockres for %s node\n",
+ lock->ml.node == dlm->node_num ? "master" :
+ "remote");
+ memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
+ }
+ spin_unlock(&res->spinlock);
+ }
+
+ /* reset any lvb flags on the lksb */
+ lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
+}
+
+void dlm_do_local_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
+ struct dlm_lock *lock)
+{
+ dlm_astlockfunc_t *fn;
+ struct dlm_lockstatus *lksb;
+
+ mlog_entry_void();
+
+ lksb = lock->lksb;
+ fn = lock->ast;
+ BUG_ON(lock->ml.node != dlm->node_num);
+
+ dlm_update_lvb(dlm, res, lock);
+ (*fn)(lock->astdata);
+}
+
+
+int dlm_do_remote_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
+ struct dlm_lock *lock)
+{
+ int ret;
+ struct dlm_lockstatus *lksb;
+ int lksbflags;
+
+ mlog_entry_void();
+
+ lksb = lock->lksb;
+ BUG_ON(lock->ml.node == dlm->node_num);
+
+ lksbflags = lksb->flags;
+ dlm_update_lvb(dlm, res, lock);
+
+ /* lock request came from another node
+ * go do the ast over there */
+ ret = dlm_send_proxy_ast(dlm, res, lock, lksbflags);
+ return ret;
+}
+
+void dlm_do_local_bast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
+ struct dlm_lock *lock, int blocked_type)
+{
+ dlm_bastlockfunc_t *fn = lock->bast;
+
+ mlog_entry_void();
+ BUG_ON(lock->ml.node != dlm->node_num);
+
+ (*fn)(lock->astdata, blocked_type);
+}
+
+
+
+int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *data)
+{
+ int ret;
+ unsigned int locklen;
+ struct dlm_ctxt *dlm = data;
+ struct dlm_lock_resource *res = NULL;
+ struct dlm_lock *lock = NULL;
+ struct dlm_proxy_ast *past = (struct dlm_proxy_ast *) msg->buf;
+ char *name;
+ struct list_head *iter, *head=NULL;
+ u64 cookie;
+ u32 flags;
+
+ if (!dlm_grab(dlm)) {
+ dlm_error(DLM_REJECTED);
+ return DLM_REJECTED;
+ }
+
+ mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
+ "Domain %s not fully joined!\n", dlm->name);
+
+ name = past->name;
+ locklen = past->namelen;
+ cookie = be64_to_cpu(past->cookie);
+ flags = be32_to_cpu(past->flags);
+
+ if (locklen > DLM_LOCKID_NAME_MAX) {
+ ret = DLM_IVBUFLEN;
+ mlog(ML_ERROR, "Invalid name length in proxy ast handler!\n");
+ goto leave;
+ }
+
+ if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
+ (LKM_PUT_LVB|LKM_GET_LVB)) {
+ mlog(ML_ERROR, "both PUT and GET lvb specified\n");
+ ret = DLM_BADARGS;
+ goto leave;
+ }
+
+ mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
+ (flags & LKM_GET_LVB ? "get lvb" : "none"));
+
+ mlog(0, "type=%d, blocked_type=%d\n", past->type, past->blocked_type);
+
+ if (past->type != DLM_AST &&
+ past->type != DLM_BAST) {
+ mlog(ML_ERROR, "Unknown ast type! %d, cookie=%"MLFu64", "
+ "name=%.*s\n", past->type, cookie, locklen, name);
+ ret = DLM_IVLOCKID;
+ goto leave;
+ }
+
+ res = dlm_lookup_lockres(dlm, name, locklen);
+ if (!res) {
+ mlog(ML_ERROR, "got %sast for unknown lockres! "
+ "cookie=%"MLFu64", name=%.*s, namelen=%u\n",
+ past->type == DLM_AST ? "" : "b",
+ cookie, locklen, name, locklen);
+ ret = DLM_IVLOCKID;
+ goto leave;
+ }
+
+ /* cannot get a proxy ast message if this node owns it */
+ BUG_ON(res->owner == dlm->node_num);
+
+ mlog(0, "lockres %.*s\n", res->lockname.len, res->lockname.name);
+
+ spin_lock(&res->spinlock);
+ if (res->state & DLM_LOCK_RES_RECOVERING) {
+ mlog(0, "responding with DLM_RECOVERING!\n");
+ ret = DLM_RECOVERING;
+ goto unlock_out;
+ }
+ if (res->state & DLM_LOCK_RES_MIGRATING) {
+ mlog(0, "responding with DLM_MIGRATING!\n");
+ ret = DLM_MIGRATING;
+ goto unlock_out;
+ }
+ /* try convert queue for both ast/bast */
+ head = &res->converting;
+ lock = NULL;
+ list_for_each(iter, head) {
+ lock = list_entry (iter, struct dlm_lock, list);
+ if (be64_to_cpu(lock->ml.cookie) == cookie)
+ goto do_ast;
+ }
+
+ /* if not on convert, try blocked for ast, granted for bast */
+ if (past->type == DLM_AST)
+ head = &res->blocked;
+ else
+ head = &res->granted;
+
+ list_for_each(iter, head) {
+ lock = list_entry (iter, struct dlm_lock, list);
+ if (be64_to_cpu(lock->ml.cookie) == cookie)
+ goto do_ast;
+ }
+
+ mlog(ML_ERROR, "got %sast for unknown lock! cookie=%"MLFu64", "
+ "name=%.*s, namelen=%u\n",
+ past->type == DLM_AST ? "" : "b", cookie, locklen, name, locklen);
+
+ ret = DLM_NORMAL;
+unlock_out:
+ spin_unlock(&res->spinlock);
+ goto leave;
+
+do_ast:
+ ret = DLM_NORMAL;
+ if (past->type == DLM_AST) {
+ /* do not alter lock refcount. switching lists. */
+ list_del_init(&lock->list);
+ list_add_tail(&lock->list, &res->granted);
+ mlog(0, "ast: adding to granted list... type=%d, "
+ "convert_type=%d\n", lock->ml.type, lock->ml.convert_type);
+ if (lock->ml.convert_type != LKM_IVMODE) {
+ lock->ml.type = lock->ml.convert_type;
+ lock->ml.convert_type = LKM_IVMODE;
+ } else {
+ // should already be there....
+ }
+
+ lock->lksb->status = DLM_NORMAL;
+
+ /* if we requested the lvb, fetch it into our lksb now */
+ if (flags & LKM_GET_LVB) {
+ BUG_ON(!(lock->lksb->flags & DLM_LKSB_GET_LVB));
+ memcpy(lock->lksb->lvb, past->lvb, DLM_LVB_LEN);
+ }
+ }
+ spin_unlock(&res->spinlock);
+
+ if (past->type == DLM_AST)
+ dlm_do_local_ast(dlm, res, lock);
+ else
+ dlm_do_local_bast(dlm, res, lock, past->blocked_type);
+
+leave:
+
+ if (res)
+ dlm_lockres_put(res);
+
+ dlm_put(dlm);
+ return ret;
+}
+
+
+
+int dlm_send_proxy_ast_msg(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
+ struct dlm_lock *lock, int msg_type,
+ int blocked_type, int flags)
+{
+ int ret = 0;
+ struct dlm_proxy_ast past;
+ struct kvec vec[2];
+ size_t veclen = 1;
+ int status;
+
+ mlog_entry("res %.*s, to=%u, type=%d, blocked_type=%d\n",
+ res->lockname.len, res->lockname.name, lock->ml.node,
+ msg_type, blocked_type);
+
+ memset(&past, 0, sizeof(struct dlm_proxy_ast));
+ past.node_idx = dlm->node_num;
+ past.type = msg_type;
+ past.blocked_type = blocked_type;
+ past.namelen = res->lockname.len;
+ memcpy(past.name, res->lockname.name, past.namelen);
+ past.cookie = lock->ml.cookie;
+
+ vec[0].iov_len = sizeof(struct dlm_proxy_ast);
+ vec[0].iov_base = &past;
+ if (flags & DLM_LKSB_GET_LVB) {
+ mlog(0, "returning requested LVB data\n");
+ be32_add_cpu(&past.flags, LKM_GET_LVB);
+ vec[1].iov_len = DLM_LVB_LEN;
+ vec[1].iov_base = lock->lksb->lvb;
+ veclen++;
+ }
+
+ ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
+ lock->ml.node, &status);
+ if (ret < 0)
+ mlog_errno(ret);
+ else {
+ if (status == DLM_RECOVERING) {
+ mlog(ML_ERROR, "sent AST to node %u, it thinks this "
+ "node is dead!\n", lock->ml.node);
+ BUG();
+ } else if (status == DLM_MIGRATING) {
+ mlog(ML_ERROR, "sent AST to node %u, it returned "
+ "DLM_MIGRATING!\n", lock->ml.node);
+ BUG();
+ } else if (status != DLM_NORMAL) {
+ mlog(ML_ERROR, "AST to node %u returned %d!\n",
+ lock->ml.node, status);
+ /* ignore it */
+ }
+ ret = 0;
+ }
+ return ret;
+}