v4.19.13 snapshot.
diff --git a/fs/ocfs2/dlmfs/userdlm.c b/fs/ocfs2/dlmfs/userdlm.c
new file mode 100644
index 0000000..9cecf48
--- /dev/null
+++ b/fs/ocfs2/dlmfs/userdlm.c
@@ -0,0 +1,689 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * userdlm.c
+ *
+ * Code which implements the kernel side of a minimal userspace
+ * interface to our DLM.
+ *
+ * Many of the functions here are pared down versions of dlmglue.c
+ * functions.
+ *
+ * Copyright (C) 2003, 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/signal.h>
+#include <linux/sched/signal.h>
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/crc32.h>
+
+#include "ocfs2_lockingver.h"
+#include "stackglue.h"
+#include "userdlm.h"
+
+#define MLOG_MASK_PREFIX ML_DLMFS
+#include "cluster/masklog.h"
+
+
+static inline struct user_lock_res *user_lksb_to_lock_res(struct ocfs2_dlm_lksb *lksb)
+{
+ return container_of(lksb, struct user_lock_res, l_lksb);
+}
+
+static inline int user_check_wait_flag(struct user_lock_res *lockres,
+ int flag)
+{
+ int ret;
+
+ spin_lock(&lockres->l_lock);
+ ret = lockres->l_flags & flag;
+ spin_unlock(&lockres->l_lock);
+
+ return ret;
+}
+
+static inline void user_wait_on_busy_lock(struct user_lock_res *lockres)
+
+{
+ wait_event(lockres->l_event,
+ !user_check_wait_flag(lockres, USER_LOCK_BUSY));
+}
+
+static inline void user_wait_on_blocked_lock(struct user_lock_res *lockres)
+
+{
+ wait_event(lockres->l_event,
+ !user_check_wait_flag(lockres, USER_LOCK_BLOCKED));
+}
+
+/* I heart container_of... */
+static inline struct ocfs2_cluster_connection *
+cluster_connection_from_user_lockres(struct user_lock_res *lockres)
+{
+ struct dlmfs_inode_private *ip;
+
+ ip = container_of(lockres,
+ struct dlmfs_inode_private,
+ ip_lockres);
+ return ip->ip_conn;
+}
+
+static struct inode *
+user_dlm_inode_from_user_lockres(struct user_lock_res *lockres)
+{
+ struct dlmfs_inode_private *ip;
+
+ ip = container_of(lockres,
+ struct dlmfs_inode_private,
+ ip_lockres);
+ return &ip->ip_vfs_inode;
+}
+
+static inline void user_recover_from_dlm_error(struct user_lock_res *lockres)
+{
+ spin_lock(&lockres->l_lock);
+ lockres->l_flags &= ~USER_LOCK_BUSY;
+ spin_unlock(&lockres->l_lock);
+}
+
+#define user_log_dlm_error(_func, _stat, _lockres) do { \
+ mlog(ML_ERROR, "Dlm error %d while calling %s on " \
+ "resource %.*s\n", _stat, _func, \
+ _lockres->l_namelen, _lockres->l_name); \
+} while (0)
+
+/* WARNING: This function lives in a world where the only three lock
+ * levels are EX, PR, and NL. It *will* have to be adjusted when more
+ * lock types are added. */
+static inline int user_highest_compat_lock_level(int level)
+{
+ int new_level = DLM_LOCK_EX;
+
+ if (level == DLM_LOCK_EX)
+ new_level = DLM_LOCK_NL;
+ else if (level == DLM_LOCK_PR)
+ new_level = DLM_LOCK_PR;
+ return new_level;
+}
+
+static void user_ast(struct ocfs2_dlm_lksb *lksb)
+{
+ struct user_lock_res *lockres = user_lksb_to_lock_res(lksb);
+ int status;
+
+ mlog(ML_BASTS, "AST fired for lockres %.*s, level %d => %d\n",
+ lockres->l_namelen, lockres->l_name, lockres->l_level,
+ lockres->l_requested);
+
+ spin_lock(&lockres->l_lock);
+
+ status = ocfs2_dlm_lock_status(&lockres->l_lksb);
+ if (status) {
+ mlog(ML_ERROR, "lksb status value of %u on lockres %.*s\n",
+ status, lockres->l_namelen, lockres->l_name);
+ spin_unlock(&lockres->l_lock);
+ return;
+ }
+
+ mlog_bug_on_msg(lockres->l_requested == DLM_LOCK_IV,
+ "Lockres %.*s, requested ivmode. flags 0x%x\n",
+ lockres->l_namelen, lockres->l_name, lockres->l_flags);
+
+ /* we're downconverting. */
+ if (lockres->l_requested < lockres->l_level) {
+ if (lockres->l_requested <=
+ user_highest_compat_lock_level(lockres->l_blocking)) {
+ lockres->l_blocking = DLM_LOCK_NL;
+ lockres->l_flags &= ~USER_LOCK_BLOCKED;
+ }
+ }
+
+ lockres->l_level = lockres->l_requested;
+ lockres->l_requested = DLM_LOCK_IV;
+ lockres->l_flags |= USER_LOCK_ATTACHED;
+ lockres->l_flags &= ~USER_LOCK_BUSY;
+
+ spin_unlock(&lockres->l_lock);
+
+ wake_up(&lockres->l_event);
+}
+
+static inline void user_dlm_grab_inode_ref(struct user_lock_res *lockres)
+{
+ struct inode *inode;
+ inode = user_dlm_inode_from_user_lockres(lockres);
+ if (!igrab(inode))
+ BUG();
+}
+
+static void user_dlm_unblock_lock(struct work_struct *work);
+
+static void __user_dlm_queue_lockres(struct user_lock_res *lockres)
+{
+ if (!(lockres->l_flags & USER_LOCK_QUEUED)) {
+ user_dlm_grab_inode_ref(lockres);
+
+ INIT_WORK(&lockres->l_work, user_dlm_unblock_lock);
+
+ queue_work(user_dlm_worker, &lockres->l_work);
+ lockres->l_flags |= USER_LOCK_QUEUED;
+ }
+}
+
+static void __user_dlm_cond_queue_lockres(struct user_lock_res *lockres)
+{
+ int queue = 0;
+
+ if (!(lockres->l_flags & USER_LOCK_BLOCKED))
+ return;
+
+ switch (lockres->l_blocking) {
+ case DLM_LOCK_EX:
+ if (!lockres->l_ex_holders && !lockres->l_ro_holders)
+ queue = 1;
+ break;
+ case DLM_LOCK_PR:
+ if (!lockres->l_ex_holders)
+ queue = 1;
+ break;
+ default:
+ BUG();
+ }
+
+ if (queue)
+ __user_dlm_queue_lockres(lockres);
+}
+
+static void user_bast(struct ocfs2_dlm_lksb *lksb, int level)
+{
+ struct user_lock_res *lockres = user_lksb_to_lock_res(lksb);
+
+ mlog(ML_BASTS, "BAST fired for lockres %.*s, blocking %d, level %d\n",
+ lockres->l_namelen, lockres->l_name, level, lockres->l_level);
+
+ spin_lock(&lockres->l_lock);
+ lockres->l_flags |= USER_LOCK_BLOCKED;
+ if (level > lockres->l_blocking)
+ lockres->l_blocking = level;
+
+ __user_dlm_queue_lockres(lockres);
+ spin_unlock(&lockres->l_lock);
+
+ wake_up(&lockres->l_event);
+}
+
+static void user_unlock_ast(struct ocfs2_dlm_lksb *lksb, int status)
+{
+ struct user_lock_res *lockres = user_lksb_to_lock_res(lksb);
+
+ mlog(ML_BASTS, "UNLOCK AST fired for lockres %.*s, flags 0x%x\n",
+ lockres->l_namelen, lockres->l_name, lockres->l_flags);
+
+ if (status)
+ mlog(ML_ERROR, "dlm returns status %d\n", status);
+
+ spin_lock(&lockres->l_lock);
+ /* The teardown flag gets set early during the unlock process,
+ * so test the cancel flag to make sure that this ast isn't
+ * for a concurrent cancel. */
+ if (lockres->l_flags & USER_LOCK_IN_TEARDOWN
+ && !(lockres->l_flags & USER_LOCK_IN_CANCEL)) {
+ lockres->l_level = DLM_LOCK_IV;
+ } else if (status == DLM_CANCELGRANT) {
+ /* We tried to cancel a convert request, but it was
+ * already granted. Don't clear the busy flag - the
+ * ast should've done this already. */
+ BUG_ON(!(lockres->l_flags & USER_LOCK_IN_CANCEL));
+ lockres->l_flags &= ~USER_LOCK_IN_CANCEL;
+ goto out_noclear;
+ } else {
+ BUG_ON(!(lockres->l_flags & USER_LOCK_IN_CANCEL));
+ /* Cancel succeeded, we want to re-queue */
+ lockres->l_requested = DLM_LOCK_IV; /* cancel an
+ * upconvert
+ * request. */
+ lockres->l_flags &= ~USER_LOCK_IN_CANCEL;
+ /* we want the unblock thread to look at it again
+ * now. */
+ if (lockres->l_flags & USER_LOCK_BLOCKED)
+ __user_dlm_queue_lockres(lockres);
+ }
+
+ lockres->l_flags &= ~USER_LOCK_BUSY;
+out_noclear:
+ spin_unlock(&lockres->l_lock);
+
+ wake_up(&lockres->l_event);
+}
+
+/*
+ * This is the userdlmfs locking protocol version.
+ *
+ * See fs/ocfs2/dlmglue.c for more details on locking versions.
+ */
+static struct ocfs2_locking_protocol user_dlm_lproto = {
+ .lp_max_version = {
+ .pv_major = OCFS2_LOCKING_PROTOCOL_MAJOR,
+ .pv_minor = OCFS2_LOCKING_PROTOCOL_MINOR,
+ },
+ .lp_lock_ast = user_ast,
+ .lp_blocking_ast = user_bast,
+ .lp_unlock_ast = user_unlock_ast,
+};
+
+static inline void user_dlm_drop_inode_ref(struct user_lock_res *lockres)
+{
+ struct inode *inode;
+ inode = user_dlm_inode_from_user_lockres(lockres);
+ iput(inode);
+}
+
+static void user_dlm_unblock_lock(struct work_struct *work)
+{
+ int new_level, status;
+ struct user_lock_res *lockres =
+ container_of(work, struct user_lock_res, l_work);
+ struct ocfs2_cluster_connection *conn =
+ cluster_connection_from_user_lockres(lockres);
+
+ mlog(0, "lockres %.*s\n", lockres->l_namelen, lockres->l_name);
+
+ spin_lock(&lockres->l_lock);
+
+ mlog_bug_on_msg(!(lockres->l_flags & USER_LOCK_QUEUED),
+ "Lockres %.*s, flags 0x%x\n",
+ lockres->l_namelen, lockres->l_name, lockres->l_flags);
+
+ /* notice that we don't clear USER_LOCK_BLOCKED here. If it's
+ * set, we want user_ast clear it. */
+ lockres->l_flags &= ~USER_LOCK_QUEUED;
+
+ /* It's valid to get here and no longer be blocked - if we get
+ * several basts in a row, we might be queued by the first
+ * one, the unblock thread might run and clear the queued
+ * flag, and finally we might get another bast which re-queues
+ * us before our ast for the downconvert is called. */
+ if (!(lockres->l_flags & USER_LOCK_BLOCKED)) {
+ mlog(ML_BASTS, "lockres %.*s USER_LOCK_BLOCKED\n",
+ lockres->l_namelen, lockres->l_name);
+ spin_unlock(&lockres->l_lock);
+ goto drop_ref;
+ }
+
+ if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) {
+ mlog(ML_BASTS, "lockres %.*s USER_LOCK_IN_TEARDOWN\n",
+ lockres->l_namelen, lockres->l_name);
+ spin_unlock(&lockres->l_lock);
+ goto drop_ref;
+ }
+
+ if (lockres->l_flags & USER_LOCK_BUSY) {
+ if (lockres->l_flags & USER_LOCK_IN_CANCEL) {
+ mlog(ML_BASTS, "lockres %.*s USER_LOCK_IN_CANCEL\n",
+ lockres->l_namelen, lockres->l_name);
+ spin_unlock(&lockres->l_lock);
+ goto drop_ref;
+ }
+
+ lockres->l_flags |= USER_LOCK_IN_CANCEL;
+ spin_unlock(&lockres->l_lock);
+
+ status = ocfs2_dlm_unlock(conn, &lockres->l_lksb,
+ DLM_LKF_CANCEL);
+ if (status)
+ user_log_dlm_error("ocfs2_dlm_unlock", status, lockres);
+ goto drop_ref;
+ }
+
+ /* If there are still incompat holders, we can exit safely
+ * without worrying about re-queueing this lock as that will
+ * happen on the last call to user_cluster_unlock. */
+ if ((lockres->l_blocking == DLM_LOCK_EX)
+ && (lockres->l_ex_holders || lockres->l_ro_holders)) {
+ spin_unlock(&lockres->l_lock);
+ mlog(ML_BASTS, "lockres %.*s, EX/PR Holders %u,%u\n",
+ lockres->l_namelen, lockres->l_name,
+ lockres->l_ex_holders, lockres->l_ro_holders);
+ goto drop_ref;
+ }
+
+ if ((lockres->l_blocking == DLM_LOCK_PR)
+ && lockres->l_ex_holders) {
+ spin_unlock(&lockres->l_lock);
+ mlog(ML_BASTS, "lockres %.*s, EX Holders %u\n",
+ lockres->l_namelen, lockres->l_name,
+ lockres->l_ex_holders);
+ goto drop_ref;
+ }
+
+ /* yay, we can downconvert now. */
+ new_level = user_highest_compat_lock_level(lockres->l_blocking);
+ lockres->l_requested = new_level;
+ lockres->l_flags |= USER_LOCK_BUSY;
+ mlog(ML_BASTS, "lockres %.*s, downconvert %d => %d\n",
+ lockres->l_namelen, lockres->l_name, lockres->l_level, new_level);
+ spin_unlock(&lockres->l_lock);
+
+ /* need lock downconvert request now... */
+ status = ocfs2_dlm_lock(conn, new_level, &lockres->l_lksb,
+ DLM_LKF_CONVERT|DLM_LKF_VALBLK,
+ lockres->l_name,
+ lockres->l_namelen);
+ if (status) {
+ user_log_dlm_error("ocfs2_dlm_lock", status, lockres);
+ user_recover_from_dlm_error(lockres);
+ }
+
+drop_ref:
+ user_dlm_drop_inode_ref(lockres);
+}
+
+static inline void user_dlm_inc_holders(struct user_lock_res *lockres,
+ int level)
+{
+ switch(level) {
+ case DLM_LOCK_EX:
+ lockres->l_ex_holders++;
+ break;
+ case DLM_LOCK_PR:
+ lockres->l_ro_holders++;
+ break;
+ default:
+ BUG();
+ }
+}
+
+/* predict what lock level we'll be dropping down to on behalf
+ * of another node, and return true if the currently wanted
+ * level will be compatible with it. */
+static inline int
+user_may_continue_on_blocked_lock(struct user_lock_res *lockres,
+ int wanted)
+{
+ BUG_ON(!(lockres->l_flags & USER_LOCK_BLOCKED));
+
+ return wanted <= user_highest_compat_lock_level(lockres->l_blocking);
+}
+
+int user_dlm_cluster_lock(struct user_lock_res *lockres,
+ int level,
+ int lkm_flags)
+{
+ int status, local_flags;
+ struct ocfs2_cluster_connection *conn =
+ cluster_connection_from_user_lockres(lockres);
+
+ if (level != DLM_LOCK_EX &&
+ level != DLM_LOCK_PR) {
+ mlog(ML_ERROR, "lockres %.*s: invalid request!\n",
+ lockres->l_namelen, lockres->l_name);
+ status = -EINVAL;
+ goto bail;
+ }
+
+ mlog(ML_BASTS, "lockres %.*s, level %d, flags = 0x%x\n",
+ lockres->l_namelen, lockres->l_name, level, lkm_flags);
+
+again:
+ if (signal_pending(current)) {
+ status = -ERESTARTSYS;
+ goto bail;
+ }
+
+ spin_lock(&lockres->l_lock);
+
+ /* We only compare against the currently granted level
+ * here. If the lock is blocked waiting on a downconvert,
+ * we'll get caught below. */
+ if ((lockres->l_flags & USER_LOCK_BUSY) &&
+ (level > lockres->l_level)) {
+ /* is someone sitting in dlm_lock? If so, wait on
+ * them. */
+ spin_unlock(&lockres->l_lock);
+
+ user_wait_on_busy_lock(lockres);
+ goto again;
+ }
+
+ if ((lockres->l_flags & USER_LOCK_BLOCKED) &&
+ (!user_may_continue_on_blocked_lock(lockres, level))) {
+ /* is the lock is currently blocked on behalf of
+ * another node */
+ spin_unlock(&lockres->l_lock);
+
+ user_wait_on_blocked_lock(lockres);
+ goto again;
+ }
+
+ if (level > lockres->l_level) {
+ local_flags = lkm_flags | DLM_LKF_VALBLK;
+ if (lockres->l_level != DLM_LOCK_IV)
+ local_flags |= DLM_LKF_CONVERT;
+
+ lockres->l_requested = level;
+ lockres->l_flags |= USER_LOCK_BUSY;
+ spin_unlock(&lockres->l_lock);
+
+ BUG_ON(level == DLM_LOCK_IV);
+ BUG_ON(level == DLM_LOCK_NL);
+
+ /* call dlm_lock to upgrade lock now */
+ status = ocfs2_dlm_lock(conn, level, &lockres->l_lksb,
+ local_flags, lockres->l_name,
+ lockres->l_namelen);
+ if (status) {
+ if ((lkm_flags & DLM_LKF_NOQUEUE) &&
+ (status != -EAGAIN))
+ user_log_dlm_error("ocfs2_dlm_lock",
+ status, lockres);
+ user_recover_from_dlm_error(lockres);
+ goto bail;
+ }
+
+ user_wait_on_busy_lock(lockres);
+ goto again;
+ }
+
+ user_dlm_inc_holders(lockres, level);
+ spin_unlock(&lockres->l_lock);
+
+ status = 0;
+bail:
+ return status;
+}
+
+static inline void user_dlm_dec_holders(struct user_lock_res *lockres,
+ int level)
+{
+ switch(level) {
+ case DLM_LOCK_EX:
+ BUG_ON(!lockres->l_ex_holders);
+ lockres->l_ex_holders--;
+ break;
+ case DLM_LOCK_PR:
+ BUG_ON(!lockres->l_ro_holders);
+ lockres->l_ro_holders--;
+ break;
+ default:
+ BUG();
+ }
+}
+
+void user_dlm_cluster_unlock(struct user_lock_res *lockres,
+ int level)
+{
+ if (level != DLM_LOCK_EX &&
+ level != DLM_LOCK_PR) {
+ mlog(ML_ERROR, "lockres %.*s: invalid request!\n",
+ lockres->l_namelen, lockres->l_name);
+ return;
+ }
+
+ spin_lock(&lockres->l_lock);
+ user_dlm_dec_holders(lockres, level);
+ __user_dlm_cond_queue_lockres(lockres);
+ spin_unlock(&lockres->l_lock);
+}
+
+void user_dlm_write_lvb(struct inode *inode,
+ const char *val,
+ unsigned int len)
+{
+ struct user_lock_res *lockres = &DLMFS_I(inode)->ip_lockres;
+ char *lvb;
+
+ BUG_ON(len > DLM_LVB_LEN);
+
+ spin_lock(&lockres->l_lock);
+
+ BUG_ON(lockres->l_level < DLM_LOCK_EX);
+ lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
+ memcpy(lvb, val, len);
+
+ spin_unlock(&lockres->l_lock);
+}
+
+ssize_t user_dlm_read_lvb(struct inode *inode,
+ char *val,
+ unsigned int len)
+{
+ struct user_lock_res *lockres = &DLMFS_I(inode)->ip_lockres;
+ char *lvb;
+ ssize_t ret = len;
+
+ BUG_ON(len > DLM_LVB_LEN);
+
+ spin_lock(&lockres->l_lock);
+
+ BUG_ON(lockres->l_level < DLM_LOCK_PR);
+ if (ocfs2_dlm_lvb_valid(&lockres->l_lksb)) {
+ lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
+ memcpy(val, lvb, len);
+ } else
+ ret = 0;
+
+ spin_unlock(&lockres->l_lock);
+ return ret;
+}
+
+void user_dlm_lock_res_init(struct user_lock_res *lockres,
+ struct dentry *dentry)
+{
+ memset(lockres, 0, sizeof(*lockres));
+
+ spin_lock_init(&lockres->l_lock);
+ init_waitqueue_head(&lockres->l_event);
+ lockres->l_level = DLM_LOCK_IV;
+ lockres->l_requested = DLM_LOCK_IV;
+ lockres->l_blocking = DLM_LOCK_IV;
+
+ /* should have been checked before getting here. */
+ BUG_ON(dentry->d_name.len >= USER_DLM_LOCK_ID_MAX_LEN);
+
+ memcpy(lockres->l_name,
+ dentry->d_name.name,
+ dentry->d_name.len);
+ lockres->l_namelen = dentry->d_name.len;
+}
+
+int user_dlm_destroy_lock(struct user_lock_res *lockres)
+{
+ int status = -EBUSY;
+ struct ocfs2_cluster_connection *conn =
+ cluster_connection_from_user_lockres(lockres);
+
+ mlog(ML_BASTS, "lockres %.*s\n", lockres->l_namelen, lockres->l_name);
+
+ spin_lock(&lockres->l_lock);
+ if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) {
+ spin_unlock(&lockres->l_lock);
+ return 0;
+ }
+
+ lockres->l_flags |= USER_LOCK_IN_TEARDOWN;
+
+ while (lockres->l_flags & USER_LOCK_BUSY) {
+ spin_unlock(&lockres->l_lock);
+
+ user_wait_on_busy_lock(lockres);
+
+ spin_lock(&lockres->l_lock);
+ }
+
+ if (lockres->l_ro_holders || lockres->l_ex_holders) {
+ spin_unlock(&lockres->l_lock);
+ goto bail;
+ }
+
+ status = 0;
+ if (!(lockres->l_flags & USER_LOCK_ATTACHED)) {
+ spin_unlock(&lockres->l_lock);
+ goto bail;
+ }
+
+ lockres->l_flags &= ~USER_LOCK_ATTACHED;
+ lockres->l_flags |= USER_LOCK_BUSY;
+ spin_unlock(&lockres->l_lock);
+
+ status = ocfs2_dlm_unlock(conn, &lockres->l_lksb, DLM_LKF_VALBLK);
+ if (status) {
+ user_log_dlm_error("ocfs2_dlm_unlock", status, lockres);
+ goto bail;
+ }
+
+ user_wait_on_busy_lock(lockres);
+
+ status = 0;
+bail:
+ return status;
+}
+
+static void user_dlm_recovery_handler_noop(int node_num,
+ void *recovery_data)
+{
+ /* We ignore recovery events */
+ return;
+}
+
+void user_dlm_set_locking_protocol(void)
+{
+ ocfs2_stack_glue_set_max_proto_version(&user_dlm_lproto.lp_max_version);
+}
+
+struct ocfs2_cluster_connection *user_dlm_register(const struct qstr *name)
+{
+ int rc;
+ struct ocfs2_cluster_connection *conn;
+
+ rc = ocfs2_cluster_connect_agnostic(name->name, name->len,
+ &user_dlm_lproto,
+ user_dlm_recovery_handler_noop,
+ NULL, &conn);
+ if (rc)
+ mlog_errno(rc);
+
+ return rc ? ERR_PTR(rc) : conn;
+}
+
+void user_dlm_unregister(struct ocfs2_cluster_connection *conn)
+{
+ ocfs2_cluster_disconnect(conn, 0);
+}