[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/dlmlock.c b/fs/ocfs2/dlm/dlmlock.c
new file mode 100644
index 0000000..d1a0038
--- /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);