[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, 530 insertions, 0 deletions

diff --git a/fs/ocfs2/dlm/dlmconvert.c b/fs/ocfs2/dlm/dlmconvert.c
new file mode 100644
index 000000000000..6001b22a997d
--- /dev/null
+++ b/fs/ocfs2/dlm/dlmconvert.c
@@ -0,0 +1,530 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * dlmconvert.c
+ *
+ * underlying calls for lock conversion
+ *
+ * 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 "dlmapi.h"
+#include "dlmcommon.h"
+
+#include "dlmconvert.h"
+
+#define MLOG_MASK_PREFIX ML_DLM
+#include "cluster/masklog.h"
+
+/* NOTE: __dlmconvert_master is the only function in here that
+ * needs a spinlock held on entry (res->spinlock) and it is the
+ * only one that holds a lock on exit (res->spinlock).
+ * All other functions in here need no locks and drop all of
+ * the locks that they acquire. */
+static enum dlm_status __dlmconvert_master(struct dlm_ctxt *dlm,
+                                           struct dlm_lock_resource *res,
+                                           struct dlm_lock *lock, int flags,
+                                           int type, int *call_ast,
+                                           int *kick_thread);
+static enum dlm_status dlm_send_remote_convert_request(struct dlm_ctxt *dlm,
+                                           struct dlm_lock_resource *res,
+                                           struct dlm_lock *lock, int flags, int type);
+
+/*
+ * this is only called directly by dlmlock(), and only when the
+ * local node is the owner of the lockres
+ * locking:
+ *   caller needs:  none
+ *   taken:         takes and drops res->spinlock
+ *   held on exit:  none
+ * returns: see __dlmconvert_master
+ */
+enum dlm_status dlmconvert_master(struct dlm_ctxt *dlm,
+                                  struct dlm_lock_resource *res,
+                                  struct dlm_lock *lock, int flags, int type)
+{
+        int call_ast = 0, kick_thread = 0;
+        enum dlm_status status;
+
+        spin_lock(&res->spinlock);
+        /* we are not in a network handler, this is fine */
+        __dlm_wait_on_lockres(res);
+        __dlm_lockres_reserve_ast(res);
+        res->state |= DLM_LOCK_RES_IN_PROGRESS;
+
+        status = __dlmconvert_master(dlm, res, lock, flags, type,
+                                     &call_ast, &kick_thread);
+
+        res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
+        spin_unlock(&res->spinlock);
+        wake_up(&res->wq);
+        if (status != DLM_NORMAL && status != DLM_NOTQUEUED)
+                dlm_error(status);
+
+        /* either queue the ast or release it */
+        if (call_ast)
+                dlm_queue_ast(dlm, lock);
+        else
+                dlm_lockres_release_ast(dlm, res);
+
+        if (kick_thread)
+                dlm_kick_thread(dlm, res);
+
+        return status;
+}
+
+/* performs lock conversion at the lockres master site
+ * locking:
+ *   caller needs:  res->spinlock
+ *   taken:         takes and drops lock->spinlock
+ *   held on exit:  res->spinlock
+ * returns: DLM_NORMAL, DLM_NOTQUEUED, DLM_DENIED
+ *   call_ast: whether ast should be called for this lock
+ *   kick_thread: whether dlm_kick_thread should be called
+ */
+static enum dlm_status __dlmconvert_master(struct dlm_ctxt *dlm,
+                                           struct dlm_lock_resource *res,
+                                           struct dlm_lock *lock, int flags,
+                                           int type, int *call_ast,
+                                           int *kick_thread)
+{
+        enum dlm_status status = DLM_NORMAL;
+        struct list_head *iter;
+        struct dlm_lock *tmplock=NULL;
+
+        assert_spin_locked(&res->spinlock);
+
+        mlog_entry("type=%d, convert_type=%d, new convert_type=%d\n",
+                   lock->ml.type, lock->ml.convert_type, type);
+
+        spin_lock(&lock->spinlock);
+
+        /* already converting? */
+        if (lock->ml.convert_type != LKM_IVMODE) {
+                mlog(ML_ERROR, "attempted to convert a lock with a lock "
+                     "conversion pending\n");
+                status = DLM_DENIED;
+                goto unlock_exit;
+        }
+
+        /* must be on grant queue to convert */
+        if (!dlm_lock_on_list(&res->granted, lock)) {
+                mlog(ML_ERROR, "attempted to convert a lock not on grant "
+                     "queue\n");
+                status = DLM_DENIED;
+                goto unlock_exit;
+        }
+
+        if (flags & LKM_VALBLK) {
+                switch (lock->ml.type) {
+                        case LKM_EXMODE:
+                                /* EX + LKM_VALBLK + convert == set lvb */
+                                mlog(0, "will set lvb: converting %s->%s\n",
+                                     dlm_lock_mode_name(lock->ml.type),
+                                     dlm_lock_mode_name(type));
+                                lock->lksb->flags |= DLM_LKSB_PUT_LVB;
+                                break;
+                        case LKM_PRMODE:
+                        case LKM_NLMODE:
+                                /* refetch if new level is not NL */
+                                if (type > LKM_NLMODE) {
+                                        mlog(0, "will fetch new value into "
+                                             "lvb: converting %s->%s\n",
+                                             dlm_lock_mode_name(lock->ml.type),
+                                             dlm_lock_mode_name(type));
+                                        lock->lksb->flags |= DLM_LKSB_GET_LVB;
+                                } else {
+                                        mlog(0, "will NOT fetch new value "
+                                             "into lvb: converting %s->%s\n",
+                                             dlm_lock_mode_name(lock->ml.type),
+                                             dlm_lock_mode_name(type));
+                                        flags &= ~(LKM_VALBLK);
+                                }
+                                break;
+                }
+        }
+
+
+        /* in-place downconvert? */
+        if (type <= lock->ml.type)
+                goto grant;
+
+        /* upconvert from here on */
+        status = DLM_NORMAL;
+        list_for_each(iter, &res->granted) {
+                tmplock = list_entry(iter, struct dlm_lock, list);
+                if (tmplock == lock)
+                        continue;
+                if (!dlm_lock_compatible(tmplock->ml.type, type))
+                        goto switch_queues;
+        }
+
+        list_for_each(iter, &res->converting) {
+                tmplock = list_entry(iter, struct dlm_lock, list);
+                if (!dlm_lock_compatible(tmplock->ml.type, type))
+                        goto switch_queues;
+                /* existing conversion requests take precedence */
+                if (!dlm_lock_compatible(tmplock->ml.convert_type, type))
+                        goto switch_queues;
+        }
+
+        /* fall thru to grant */
+
+grant:
+        mlog(0, "res %.*s, granting %s lock\n", res->lockname.len,
+             res->lockname.name, dlm_lock_mode_name(type));
+        /* immediately grant the new lock type */
+        lock->lksb->status = DLM_NORMAL;
+        if (lock->ml.node == dlm->node_num)
+                mlog(0, "doing in-place convert for nonlocal lock\n");
+        lock->ml.type = type;
+        status = DLM_NORMAL;
+        *call_ast = 1;
+        goto unlock_exit;
+
+switch_queues:
+        if (flags & LKM_NOQUEUE) {
+                mlog(0, "failed to convert NOQUEUE lock %.*s from "
+                     "%d to %d...\n", res->lockname.len, res->lockname.name,
+                     lock->ml.type, type);
+                status = DLM_NOTQUEUED;
+                goto unlock_exit;
+        }
+        mlog(0, "res %.*s, queueing...\n", res->lockname.len,
+             res->lockname.name);
+
+        lock->ml.convert_type = type;
+        /* do not alter lock refcount.  switching lists. */
+        list_del_init(&lock->list);
+        list_add_tail(&lock->list, &res->converting);
+
+unlock_exit:
+        spin_unlock(&lock->spinlock);
+        if (status == DLM_DENIED) {
+                __dlm_print_one_lock_resource(res);
+        }
+        if (status == DLM_NORMAL)
+                *kick_thread = 1;
+        return status;
+}
+
+void dlm_revert_pending_convert(struct dlm_lock_resource *res,
+                                struct dlm_lock *lock)
+{
+        /* do not alter lock refcount.  switching lists. */
+        list_del_init(&lock->list);
+        list_add_tail(&lock->list, &res->granted);
+        lock->ml.convert_type = LKM_IVMODE;
+        lock->lksb->flags &= ~(DLM_LKSB_GET_LVB|DLM_LKSB_PUT_LVB);
+}
+
+/* messages the master site to do lock conversion
+ * locking:
+ *   caller needs:  none
+ *   taken:         takes and drops res->spinlock, uses DLM_LOCK_RES_IN_PROGRESS
+ *   held on exit:  none
+ * returns: DLM_NORMAL, DLM_RECOVERING, status from remote node
+ */
+enum dlm_status dlmconvert_remote(struct dlm_ctxt *dlm,
+                                  struct dlm_lock_resource *res,
+                                  struct dlm_lock *lock, int flags, int type)
+{
+        enum dlm_status status;
+
+        mlog(0, "type=%d, convert_type=%d, busy=%d\n", lock->ml.type,
+             lock->ml.convert_type, res->state & DLM_LOCK_RES_IN_PROGRESS);
+
+        spin_lock(&res->spinlock);
+        if (res->state & DLM_LOCK_RES_RECOVERING) {
+                mlog(0, "bailing out early since res is RECOVERING "
+                     "on secondary queue\n");
+                /* __dlm_print_one_lock_resource(res); */
+                status = DLM_RECOVERING;
+                goto bail;
+        }
+        /* will exit this call with spinlock held */
+        __dlm_wait_on_lockres(res);
+
+        if (lock->ml.convert_type != LKM_IVMODE) {
+                __dlm_print_one_lock_resource(res);
+                mlog(ML_ERROR, "converting a remote lock that is already "
+                     "converting! (cookie=%"MLFu64", conv=%d)\n",
+                     lock->ml.cookie, lock->ml.convert_type);
+                status = DLM_DENIED;
+                goto bail;
+        }
+        res->state |= DLM_LOCK_RES_IN_PROGRESS;
+        /* move lock to local convert queue */
+        /* do not alter lock refcount.  switching lists. */
+        list_del_init(&lock->list);
+        list_add_tail(&lock->list, &res->converting);
+        lock->convert_pending = 1;
+        lock->ml.convert_type = type;
+
+        if (flags & LKM_VALBLK) {
+                if (lock->ml.type == LKM_EXMODE) {
+                        flags |= LKM_PUT_LVB;
+                        lock->lksb->flags |= DLM_LKSB_PUT_LVB;
+                } else {
+                        if (lock->ml.convert_type == LKM_NLMODE)
+                                flags &= ~LKM_VALBLK;
+                        else {
+                                flags |= LKM_GET_LVB;
+                                lock->lksb->flags |= DLM_LKSB_GET_LVB;
+                        }
+                }
+        }
+        spin_unlock(&res->spinlock);
+
+        /* no locks held here.
+         * need to wait for a reply as to whether it got queued or not. */
+        status = dlm_send_remote_convert_request(dlm, res, lock, flags, type);
+
+        spin_lock(&res->spinlock);
+        res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
+        lock->convert_pending = 0;
+        /* if it failed, move it back to granted queue */
+        if (status != DLM_NORMAL) {
+                if (status != DLM_NOTQUEUED)
+                        dlm_error(status);
+                dlm_revert_pending_convert(res, lock);
+        }
+bail:
+        spin_unlock(&res->spinlock);
+
+        /* TODO: should this be a wake_one? */
+        /* wake up any IN_PROGRESS waiters */
+        wake_up(&res->wq);
+
+        return status;
+}
+
+/* sends DLM_CONVERT_LOCK_MSG to master site
+ * locking:
+ *   caller needs:  none
+ *   taken:         none
+ *   held on exit:  none
+ * returns: DLM_NOLOCKMGR, status from remote node
+ */
+static enum dlm_status dlm_send_remote_convert_request(struct dlm_ctxt *dlm,
+                                           struct dlm_lock_resource *res,
+                                           struct dlm_lock *lock, int flags, int type)
+{
+        struct dlm_convert_lock convert;
+        int tmpret;
+        enum dlm_status ret;
+        int status = 0;
+        struct kvec vec[2];
+        size_t veclen = 1;
+
+        mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);
+
+        memset(&convert, 0, sizeof(struct dlm_convert_lock));
+        convert.node_idx = dlm->node_num;
+        convert.requested_type = type;
+        convert.cookie = lock->ml.cookie;
+        convert.namelen = res->lockname.len;
+        convert.flags = cpu_to_be32(flags);
+        memcpy(convert.name, res->lockname.name, convert.namelen);
+
+        vec[0].iov_len = sizeof(struct dlm_convert_lock);
+        vec[0].iov_base = &convert;
+
+        if (flags & LKM_PUT_LVB) {
+                /* extra data to send if we are updating lvb */
+                vec[1].iov_len = DLM_LVB_LEN;
+                vec[1].iov_base = lock->lksb->lvb;
+                veclen++;
+        }
+
+        tmpret = o2net_send_message_vec(DLM_CONVERT_LOCK_MSG, dlm->key,
+                                        vec, veclen, res->owner, &status);
+        if (tmpret >= 0) {
+                // successfully sent and received
+                ret = status;  // this is already a dlm_status
+                if (ret == DLM_RECOVERING) {
+                        mlog(0, "node %u returned DLM_RECOVERING from convert "
+                             "message!\n", res->owner);
+                } else if (ret == DLM_MIGRATING) {
+                        mlog(0, "node %u returned DLM_MIGRATING from convert "
+                             "message!\n", res->owner);
+                } else if (ret == DLM_FORWARD) {
+                        mlog(0, "node %u returned DLM_FORWARD from convert "
+                             "message!\n", res->owner);
+                } else if (ret != DLM_NORMAL && ret != DLM_NOTQUEUED)
+                        dlm_error(ret);
+        } else {
+                mlog_errno(tmpret);
+                if (dlm_is_host_down(tmpret)) {
+                        ret = DLM_RECOVERING;
+                        mlog(0, "node %u died so returning DLM_RECOVERING "
+                             "from convert message!\n", res->owner);
+                } else {
+                        ret = dlm_err_to_dlm_status(tmpret);
+                }
+        }
+
+        return ret;
+}
+
+/* handler for DLM_CONVERT_LOCK_MSG on master site
+ * locking:
+ *   caller needs:  none
+ *   taken:         takes and drop res->spinlock
+ *   held on exit:  none
+ * returns: DLM_NORMAL, DLM_IVLOCKID, DLM_BADARGS,
+ *          status from __dlmconvert_master
+ */
+int dlm_convert_lock_handler(struct o2net_msg *msg, u32 len, void *data)
+{
+        struct dlm_ctxt *dlm = data;
+        struct dlm_convert_lock *cnv = (struct dlm_convert_lock *)msg->buf;
+        struct dlm_lock_resource *res = NULL;
+        struct list_head *iter;
+        struct dlm_lock *lock = NULL;
+        struct dlm_lockstatus *lksb;
+        enum dlm_status status = DLM_NORMAL;
+        u32 flags;
+        int call_ast = 0, kick_thread = 0;
+
+        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);
+
+        if (cnv->namelen > DLM_LOCKID_NAME_MAX) {
+                status = DLM_IVBUFLEN;
+                dlm_error(status);
+                goto leave;
+        }
+
+        flags = be32_to_cpu(cnv->flags);
+
+        if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
+             (LKM_PUT_LVB|LKM_GET_LVB)) {
+                mlog(ML_ERROR, "both PUT and GET lvb specified\n");
+                status = DLM_BADARGS;
+                goto leave;
+        }
+
+        mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
+             (flags & LKM_GET_LVB ? "get lvb" : "none"));
+
+        status = DLM_IVLOCKID;
+        res = dlm_lookup_lockres(dlm, cnv->name, cnv->namelen);
+        if (!res) {
+                dlm_error(status);
+                goto leave;
+        }
+
+        spin_lock(&res->spinlock);
+        list_for_each(iter, &res->granted) {
+                lock = list_entry(iter, struct dlm_lock, list);
+                if (lock->ml.cookie == cnv->cookie &&
+                    lock->ml.node == cnv->node_idx) {
+                        dlm_lock_get(lock);
+                        break;
+                }
+                lock = NULL;
+        }
+        spin_unlock(&res->spinlock);
+        if (!lock) {
+                status = DLM_IVLOCKID;
+                dlm_error(status);
+                goto leave;
+        }
+
+        /* found the lock */
+        lksb = lock->lksb;
+
+        /* see if caller needed to get/put lvb */
+        if (flags & LKM_PUT_LVB) {
+                BUG_ON(lksb->flags & (DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB));
+                lksb->flags |= DLM_LKSB_PUT_LVB;
+                memcpy(&lksb->lvb[0], &cnv->lvb[0], DLM_LVB_LEN);
+        } else if (flags & LKM_GET_LVB) {
+                BUG_ON(lksb->flags & (DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB));
+                lksb->flags |= DLM_LKSB_GET_LVB;
+        }
+
+        spin_lock(&res->spinlock);
+        status = __dlm_lockres_state_to_status(res);
+        if (status == DLM_NORMAL) {
+                __dlm_lockres_reserve_ast(res);
+                res->state |= DLM_LOCK_RES_IN_PROGRESS;
+                status = __dlmconvert_master(dlm, res, lock, flags,
+                                             cnv->requested_type,
+                                             &call_ast, &kick_thread);
+                res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
+        }
+        spin_unlock(&res->spinlock);
+
+        if (status != DLM_NORMAL) {
+                if (status != DLM_NOTQUEUED)
+                        dlm_error(status);
+                lksb->flags &= ~(DLM_LKSB_GET_LVB|DLM_LKSB_PUT_LVB);
+        }
+
+leave:
+        if (!lock)
+                mlog(ML_ERROR, "did not find lock to convert on grant queue! "
+                               "cookie=%"MLFu64"\n",
+                     cnv->cookie);
+        else
+                dlm_lock_put(lock);
+
+        /* either queue the ast or release it */
+        if (call_ast)
+                dlm_queue_ast(dlm, lock);
+        else
+                dlm_lockres_release_ast(dlm, res);
+
+        if (kick_thread)
+                dlm_kick_thread(dlm, res);
+
+        if (res)
+                dlm_lockres_put(res);
+
+        dlm_put(dlm);
+
+        return status;
+}