[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>

1 files changed, 466 insertions, 0 deletions

diff --git a/fs/ocfs2/dlm/dlmast.c b/fs/ocfs2/dlm/dlmast.c
new file mode 100644
index 000000000000..8d17d28ef91c
--- /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;
+}