[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, 676 insertions, 0 deletions

diff --git a/fs/ocfs2/dlm/dlmlock.c b/fs/ocfs2/dlm/dlmlock.c
new file mode 100644
index 00000000000..d1a0038557a
--- /dev/null
+++ b/fs/ocfs2/dlm/dlmlock.c
@@ -0,0 +1,676 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * dlmlock.c
+ *
+ * underlying calls for lock creation
+ *
+ * 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 <linux/delay.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"
+
+static spinlock_t dlm_cookie_lock = SPIN_LOCK_UNLOCKED;
+static u64 dlm_next_cookie = 1;
+
+static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
+                                               struct dlm_lock_resource *res,
+                                               struct dlm_lock *lock, int flags);
+static void dlm_init_lock(struct dlm_lock *newlock, int type,
+                          u8 node, u64 cookie);
+static void dlm_lock_release(struct kref *kref);
+static void dlm_lock_detach_lockres(struct dlm_lock *lock);
+
+/* Tell us whether we can grant a new lock request.
+ * locking:
+ *   caller needs:  res->spinlock
+ *   taken:         none
+ *   held on exit:  none
+ * returns: 1 if the lock can be granted, 0 otherwise.
+ */
+static int dlm_can_grant_new_lock(struct dlm_lock_resource *res,
+                                  struct dlm_lock *lock)
+{
+        struct list_head *iter;
+        struct dlm_lock *tmplock;
+
+        list_for_each(iter, &res->granted) {
+                tmplock = list_entry(iter, struct dlm_lock, list);
+
+                if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
+                        return 0;
+        }
+
+        list_for_each(iter, &res->converting) {
+                tmplock = list_entry(iter, struct dlm_lock, list);
+
+                if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
+                        return 0;
+        }
+
+        return 1;
+}
+
+/* performs lock creation at the lockres master site
+ * locking:
+ *   caller needs:  none
+ *   taken:         takes and drops res->spinlock
+ *   held on exit:  none
+ * returns: DLM_NORMAL, DLM_NOTQUEUED
+ */
+static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm,
+                                      struct dlm_lock_resource *res,
+                                      struct dlm_lock *lock, int flags)
+{
+        int call_ast = 0, kick_thread = 0;
+        enum dlm_status status = DLM_NORMAL;
+
+        mlog_entry("type=%d\n", lock->ml.type);
+
+        spin_lock(&res->spinlock);
+        /* if called from dlm_create_lock_handler, need to
+         * ensure it will not sleep in dlm_wait_on_lockres */
+        status = __dlm_lockres_state_to_status(res);
+        if (status != DLM_NORMAL &&
+            lock->ml.node != dlm->node_num) {
+                /* erf.  state changed after lock was dropped. */
+                spin_unlock(&res->spinlock);
+                dlm_error(status);
+                return status;
+        }
+        __dlm_wait_on_lockres(res);
+        __dlm_lockres_reserve_ast(res);
+
+        if (dlm_can_grant_new_lock(res, lock)) {
+                mlog(0, "I can grant this lock right away\n");
+                /* got it right away */
+                lock->lksb->status = DLM_NORMAL;
+                status = DLM_NORMAL;
+                dlm_lock_get(lock);
+                list_add_tail(&lock->list, &res->granted);
+
+                /* for the recovery lock, we can't allow the ast
+                 * to be queued since the dlmthread is already
+                 * frozen.  but the recovery lock is always locked
+                 * with LKM_NOQUEUE so we do not need the ast in
+                 * this special case */
+                if (!dlm_is_recovery_lock(res->lockname.name,
+                                          res->lockname.len)) {
+                        kick_thread = 1;
+                        call_ast = 1;
+                }
+        } else {
+                /* for NOQUEUE request, unless we get the
+                 * lock right away, return DLM_NOTQUEUED */
+                if (flags & LKM_NOQUEUE)
+                        status = DLM_NOTQUEUED;
+                else {
+                        dlm_lock_get(lock);
+                        list_add_tail(&lock->list, &res->blocked);
+                        kick_thread = 1;
+                }
+        }
+
+        spin_unlock(&res->spinlock);
+        wake_up(&res->wq);
+
+        /* either queue the ast or release it */
+        if (call_ast)
+                dlm_queue_ast(dlm, lock);
+        else
+                dlm_lockres_release_ast(dlm, res);
+
+        dlm_lockres_calc_usage(dlm, res);
+        if (kick_thread)
+                dlm_kick_thread(dlm, res);
+
+        return status;
+}
+
+void dlm_revert_pending_lock(struct dlm_lock_resource *res,
+                             struct dlm_lock *lock)
+{
+        /* remove from local queue if it failed */
+        list_del_init(&lock->list);
+        lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
+}
+
+
+/*
+ * locking:
+ *   caller needs:  none
+ *   taken:         takes and drops res->spinlock
+ *   held on exit:  none
+ * returns: DLM_DENIED, DLM_RECOVERING, or net status
+ */
+static enum dlm_status dlmlock_remote(struct dlm_ctxt *dlm,
+                                      struct dlm_lock_resource *res,
+                                      struct dlm_lock *lock, int flags)
+{
+        enum dlm_status status = DLM_DENIED;
+
+        mlog_entry("type=%d\n", lock->ml.type);
+        mlog(0, "lockres %.*s, flags = 0x%x\n", res->lockname.len,
+             res->lockname.name, flags);
+
+        spin_lock(&res->spinlock);
+
+        /* will exit this call with spinlock held */
+        __dlm_wait_on_lockres(res);
+        res->state |= DLM_LOCK_RES_IN_PROGRESS;
+
+        /* add lock to local (secondary) queue */
+        dlm_lock_get(lock);
+        list_add_tail(&lock->list, &res->blocked);
+        lock->lock_pending = 1;
+        spin_unlock(&res->spinlock);
+
+        /* spec seems to say that you will get DLM_NORMAL when the lock
+         * has been queued, meaning we need to wait for a reply here. */
+        status = dlm_send_remote_lock_request(dlm, res, lock, flags);
+
+        spin_lock(&res->spinlock);
+        res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
+        lock->lock_pending = 0;
+        if (status != DLM_NORMAL) {
+                if (status != DLM_NOTQUEUED)
+                        dlm_error(status);
+                dlm_revert_pending_lock(res, lock);
+                dlm_lock_put(lock);
+        }
+        spin_unlock(&res->spinlock);
+
+        dlm_lockres_calc_usage(dlm, res);
+
+        wake_up(&res->wq);
+        return status;
+}
+
+
+/* for remote lock creation.
+ * locking:
+ *   caller needs:  none, but need res->state & DLM_LOCK_RES_IN_PROGRESS
+ *   taken:         none
+ *   held on exit:  none
+ * returns: DLM_NOLOCKMGR, or net status
+ */
+static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
+                                               struct dlm_lock_resource *res,
+                                               struct dlm_lock *lock, int flags)
+{
+        struct dlm_create_lock create;
+        int tmpret, status = 0;
+        enum dlm_status ret;
+
+        mlog_entry_void();
+
+        memset(&create, 0, sizeof(create));
+        create.node_idx = dlm->node_num;
+        create.requested_type = lock->ml.type;
+        create.cookie = lock->ml.cookie;
+        create.namelen = res->lockname.len;
+        create.flags = cpu_to_be32(flags);
+        memcpy(create.name, res->lockname.name, create.namelen);
+
+        tmpret = o2net_send_message(DLM_CREATE_LOCK_MSG, dlm->key, &create,
+                                    sizeof(create), res->owner, &status);
+        if (tmpret >= 0) {
+                // successfully sent and received
+                ret = status;  // this is already a dlm_status
+        } else {
+                mlog_errno(tmpret);
+                if (dlm_is_host_down(tmpret)) {
+                        ret = DLM_RECOVERING;
+                        mlog(0, "node %u died so returning DLM_RECOVERING "
+                             "from lock message!\n", res->owner);
+                } else {
+                        ret = dlm_err_to_dlm_status(tmpret);
+                }
+        }
+
+        return ret;
+}
+
+void dlm_lock_get(struct dlm_lock *lock)
+{
+        kref_get(&lock->lock_refs);
+}
+
+void dlm_lock_put(struct dlm_lock *lock)
+{
+        kref_put(&lock->lock_refs, dlm_lock_release);
+}
+
+static void dlm_lock_release(struct kref *kref)
+{
+        struct dlm_lock *lock;
+
+        lock = container_of(kref, struct dlm_lock, lock_refs);
+
+        BUG_ON(!list_empty(&lock->list));
+        BUG_ON(!list_empty(&lock->ast_list));
+        BUG_ON(!list_empty(&lock->bast_list));
+        BUG_ON(lock->ast_pending);
+        BUG_ON(lock->bast_pending);
+
+        dlm_lock_detach_lockres(lock);
+
+        if (lock->lksb_kernel_allocated) {
+                mlog(0, "freeing kernel-allocated lksb\n");
+                kfree(lock->lksb);
+        }
+        kfree(lock);
+}
+
+/* associate a lock with it's lockres, getting a ref on the lockres */
+void dlm_lock_attach_lockres(struct dlm_lock *lock,
+                             struct dlm_lock_resource *res)
+{
+        dlm_lockres_get(res);
+        lock->lockres = res;
+}
+
+/* drop ref on lockres, if there is still one associated with lock */
+static void dlm_lock_detach_lockres(struct dlm_lock *lock)
+{
+        struct dlm_lock_resource *res;
+
+        res = lock->lockres;
+        if (res) {
+                lock->lockres = NULL;
+                mlog(0, "removing lock's lockres reference\n");
+                dlm_lockres_put(res);
+        }
+}
+
+static void dlm_init_lock(struct dlm_lock *newlock, int type,
+                          u8 node, u64 cookie)
+{
+        INIT_LIST_HEAD(&newlock->list);
+        INIT_LIST_HEAD(&newlock->ast_list);
+        INIT_LIST_HEAD(&newlock->bast_list);
+        spin_lock_init(&newlock->spinlock);
+        newlock->ml.type = type;
+        newlock->ml.convert_type = LKM_IVMODE;
+        newlock->ml.highest_blocked = LKM_IVMODE;
+        newlock->ml.node = node;
+        newlock->ml.pad1 = 0;
+        newlock->ml.list = 0;
+        newlock->ml.flags = 0;
+        newlock->ast = NULL;
+        newlock->bast = NULL;
+        newlock->astdata = NULL;
+        newlock->ml.cookie = cpu_to_be64(cookie);
+        newlock->ast_pending = 0;
+        newlock->bast_pending = 0;
+        newlock->convert_pending = 0;
+        newlock->lock_pending = 0;
+        newlock->unlock_pending = 0;
+        newlock->cancel_pending = 0;
+        newlock->lksb_kernel_allocated = 0;
+
+        kref_init(&newlock->lock_refs);
+}
+
+struct dlm_lock * dlm_new_lock(int type, u8 node, u64 cookie,
+                               struct dlm_lockstatus *lksb)
+{
+        struct dlm_lock *lock;
+        int kernel_allocated = 0;
+
+        lock = kcalloc(1, sizeof(*lock), GFP_KERNEL);
+        if (!lock)
+                return NULL;
+
+        if (!lksb) {
+                /* zero memory only if kernel-allocated */
+                lksb = kcalloc(1, sizeof(*lksb), GFP_KERNEL);
+                if (!lksb) {
+                        kfree(lock);
+                        return NULL;
+                }
+                kernel_allocated = 1;
+        }
+
+        dlm_init_lock(lock, type, node, cookie);
+        if (kernel_allocated)
+                lock->lksb_kernel_allocated = 1;
+        lock->lksb = lksb;
+        lksb->lockid = lock;
+        return lock;
+}
+
+/* handler for lock creation net message
+ * locking:
+ *   caller needs:  none
+ *   taken:         takes and drops res->spinlock
+ *   held on exit:  none
+ * returns: DLM_NORMAL, DLM_SYSERR, DLM_IVLOCKID, DLM_NOTQUEUED
+ */
+int dlm_create_lock_handler(struct o2net_msg *msg, u32 len, void *data)
+{
+        struct dlm_ctxt *dlm = data;
+        struct dlm_create_lock *create = (struct dlm_create_lock *)msg->buf;
+        struct dlm_lock_resource *res = NULL;
+        struct dlm_lock *newlock = NULL;
+        struct dlm_lockstatus *lksb = NULL;
+        enum dlm_status status = DLM_NORMAL;
+        char *name;
+        unsigned int namelen;
+
+        BUG_ON(!dlm);
+
+        mlog_entry_void();
+
+        if (!dlm_grab(dlm))
+                return DLM_REJECTED;
+
+        mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
+                        "Domain %s not fully joined!\n", dlm->name);
+
+        name = create->name;
+        namelen = create->namelen;
+
+        status = DLM_IVBUFLEN;
+        if (namelen > DLM_LOCKID_NAME_MAX) {
+                dlm_error(status);
+                goto leave;
+        }
+
+        status = DLM_SYSERR;
+        newlock = dlm_new_lock(create->requested_type,
+                               create->node_idx,
+                               be64_to_cpu(create->cookie), NULL);
+        if (!newlock) {
+                dlm_error(status);
+                goto leave;
+        }
+
+        lksb = newlock->lksb;
+
+        if (be32_to_cpu(create->flags) & LKM_GET_LVB) {
+                lksb->flags |= DLM_LKSB_GET_LVB;
+                mlog(0, "set DLM_LKSB_GET_LVB flag\n");
+        }
+
+        status = DLM_IVLOCKID;
+        res = dlm_lookup_lockres(dlm, name, namelen);
+        if (!res) {
+                dlm_error(status);
+                goto leave;
+        }
+
+        spin_lock(&res->spinlock);
+        status = __dlm_lockres_state_to_status(res);
+        spin_unlock(&res->spinlock);
+
+        if (status != DLM_NORMAL) {
+                mlog(0, "lockres recovering/migrating/in-progress\n");
+                goto leave;
+        }
+
+        dlm_lock_attach_lockres(newlock, res);
+
+        status = dlmlock_master(dlm, res, newlock, be32_to_cpu(create->flags));
+leave:
+        if (status != DLM_NORMAL)
+                if (newlock)
+                        dlm_lock_put(newlock);
+
+        if (res)
+                dlm_lockres_put(res);
+
+        dlm_put(dlm);
+
+        return status;
+}
+
+
+/* fetch next node-local (u8 nodenum + u56 cookie) into u64 */
+static inline void dlm_get_next_cookie(u8 node_num, u64 *cookie)
+{
+        u64 tmpnode = node_num;
+
+        /* shift single byte of node num into top 8 bits */
+        tmpnode <<= 56;
+
+        spin_lock(&dlm_cookie_lock);
+        *cookie = (dlm_next_cookie | tmpnode);
+        if (++dlm_next_cookie & 0xff00000000000000ull) {
+                mlog(0, "This node's cookie will now wrap!\n");
+                dlm_next_cookie = 1;
+        }
+        spin_unlock(&dlm_cookie_lock);
+}
+
+enum dlm_status dlmlock(struct dlm_ctxt *dlm, int mode,
+                        struct dlm_lockstatus *lksb, int flags,
+                        const char *name, dlm_astlockfunc_t *ast, void *data,
+                        dlm_bastlockfunc_t *bast)
+{
+        enum dlm_status status;
+        struct dlm_lock_resource *res = NULL;
+        struct dlm_lock *lock = NULL;
+        int convert = 0, recovery = 0;
+
+        /* yes this function is a mess.
+         * TODO: clean this up.  lots of common code in the
+         *       lock and convert paths, especially in the retry blocks */
+        if (!lksb) {
+                dlm_error(DLM_BADARGS);
+                return DLM_BADARGS;
+        }
+
+        status = DLM_BADPARAM;
+        if (mode != LKM_EXMODE && mode != LKM_PRMODE && mode != LKM_NLMODE) {
+                dlm_error(status);
+                goto error;
+        }
+
+        if (flags & ~LKM_VALID_FLAGS) {
+                dlm_error(status);
+                goto error;
+        }
+
+        convert = (flags & LKM_CONVERT);
+        recovery = (flags & LKM_RECOVERY);
+
+        if (recovery &&
+            (!dlm_is_recovery_lock(name, strlen(name)) || convert) ) {
+                dlm_error(status);
+                goto error;
+        }
+        if (convert && (flags & LKM_LOCAL)) {
+                mlog(ML_ERROR, "strange LOCAL convert request!\n");
+                goto error;
+        }
+
+        if (convert) {
+                /* CONVERT request */
+
+                /* if converting, must pass in a valid dlm_lock */
+                lock = lksb->lockid;
+                if (!lock) {
+                        mlog(ML_ERROR, "NULL lock pointer in convert "
+                             "request\n");
+                        goto error;
+                }
+
+                res = lock->lockres;
+                if (!res) {
+                        mlog(ML_ERROR, "NULL lockres pointer in convert "
+                             "request\n");
+                        goto error;
+                }
+                dlm_lockres_get(res);
+
+                /* XXX: for ocfs2 purposes, the ast/bast/astdata/lksb are
+                 * static after the original lock call.  convert requests will
+                 * ensure that everything is the same, or return DLM_BADARGS.
+                 * this means that DLM_DENIED_NOASTS will never be returned.
+                 */
+                if (lock->lksb != lksb || lock->ast != ast ||
+                    lock->bast != bast || lock->astdata != data) {
+                        status = DLM_BADARGS;
+                        mlog(ML_ERROR, "new args:  lksb=%p, ast=%p, bast=%p, "
+                             "astdata=%p\n", lksb, ast, bast, data);
+                        mlog(ML_ERROR, "orig args: lksb=%p, ast=%p, bast=%p, "
+                             "astdata=%p\n", lock->lksb, lock->ast,
+                             lock->bast, lock->astdata);
+                        goto error;
+                }
+retry_convert:
+                dlm_wait_for_recovery(dlm);
+
+                if (res->owner == dlm->node_num)
+                        status = dlmconvert_master(dlm, res, lock, flags, mode);
+                else
+                        status = dlmconvert_remote(dlm, res, lock, flags, mode);
+                if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
+                    status == DLM_FORWARD) {
+                        /* for now, see how this works without sleeping
+                         * and just retry right away.  I suspect the reco
+                         * or migration will complete fast enough that
+                         * no waiting will be necessary */
+                        mlog(0, "retrying convert with migration/recovery/"
+                             "in-progress\n");
+                        msleep(100);
+                        goto retry_convert;
+                }
+        } else {
+                u64 tmpcookie;
+
+                /* LOCK request */
+                status = DLM_BADARGS;
+                if (!name) {
+                        dlm_error(status);
+                        goto error;
+                }
+
+                status = DLM_IVBUFLEN;
+                if (strlen(name) > DLM_LOCKID_NAME_MAX || strlen(name) < 1) {
+                        dlm_error(status);
+                        goto error;
+                }
+
+                dlm_get_next_cookie(dlm->node_num, &tmpcookie);
+                lock = dlm_new_lock(mode, dlm->node_num, tmpcookie, lksb);
+                if (!lock) {
+                        dlm_error(status);
+                        goto error;
+                }
+
+                if (!recovery)
+                        dlm_wait_for_recovery(dlm);
+
+                /* find or create the lock resource */
+                res = dlm_get_lock_resource(dlm, name, flags);
+                if (!res) {
+                        status = DLM_IVLOCKID;
+                        dlm_error(status);
+                        goto error;
+                }
+
+                mlog(0, "type=%d, flags = 0x%x\n", mode, flags);
+                mlog(0, "creating lock: lock=%p res=%p\n", lock, res);
+
+                dlm_lock_attach_lockres(lock, res);
+                lock->ast = ast;
+                lock->bast = bast;
+                lock->astdata = data;
+
+retry_lock:
+                if (flags & LKM_VALBLK) {
+                        mlog(0, "LKM_VALBLK passed by caller\n");
+
+                        /* LVB requests for non PR, PW or EX locks are
+                         * ignored. */
+                        if (mode < LKM_PRMODE)
+                                flags &= ~LKM_VALBLK;
+                        else {
+                                flags |= LKM_GET_LVB;
+                                lock->lksb->flags |= DLM_LKSB_GET_LVB;
+                        }
+                }
+
+                if (res->owner == dlm->node_num)
+                        status = dlmlock_master(dlm, res, lock, flags);
+                else
+                        status = dlmlock_remote(dlm, res, lock, flags);
+
+                if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
+                    status == DLM_FORWARD) {
+                        mlog(0, "retrying lock with migration/"
+                             "recovery/in progress\n");
+                        msleep(100);
+                        dlm_wait_for_recovery(dlm);
+                        goto retry_lock;
+                }
+
+                if (status != DLM_NORMAL) {
+                        lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
+                        if (status != DLM_NOTQUEUED)
+                                dlm_error(status);
+                        goto error;
+                }
+        }
+
+error:
+        if (status != DLM_NORMAL) {
+                if (lock && !convert)
+                        dlm_lock_put(lock);
+                // this is kind of unnecessary
+                lksb->status = status;
+        }
+
+        /* put lockres ref from the convert path
+         * or from dlm_get_lock_resource */
+        if (res)
+                dlm_lockres_put(res);
+
+        return status;
+}
+EXPORT_SYMBOL_GPL(dlmlock);