Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm:
  dlm: choose better identifiers
  dlm: remove bkl
  dlm: fix address compare
  dlm: fix locking of lockspace list in dlm_scand
  dlm: detect available userspace daemon
  dlm: allow multiple lockspace creates

7 files changed, 276 insertions, 98 deletions

diff --git a/fs/dlm/config.c b/fs/dlm/config.c
index 89d2fb7b991a..fd9859f92fad 100644
--- a/fs/dlm/config.c
+++ b/fs/dlm/config.c
@@ -14,6 +14,9 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/configfs.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <net/ipv6.h>
 #include <net/sock.h>
 
 #include "config.h"
@@ -377,24 +380,24 @@ static struct config_item_type node_type = {
         .ct_owner = THIS_MODULE,
 };
 
-static struct dlm_cluster *to_cluster(struct config_item *i)
+static struct dlm_cluster *config_item_to_cluster(struct config_item *i)
 {
         return i ? container_of(to_config_group(i), struct dlm_cluster, group) :
                    NULL;
 }
 
-static struct dlm_space *to_space(struct config_item *i)
+static struct dlm_space *config_item_to_space(struct config_item *i)
 {
         return i ? container_of(to_config_group(i), struct dlm_space, group) :
                    NULL;
 }
 
-static struct dlm_comm *to_comm(struct config_item *i)
+static struct dlm_comm *config_item_to_comm(struct config_item *i)
 {
         return i ? container_of(i, struct dlm_comm, item) : NULL;
 }
 
-static struct dlm_node *to_node(struct config_item *i)
+static struct dlm_node *config_item_to_node(struct config_item *i)
 {
         return i ? container_of(i, struct dlm_node, item) : NULL;
 }
@@ -450,7 +453,7 @@ static struct config_group *make_cluster(struct config_group *g,
 
 static void drop_cluster(struct config_group *g, struct config_item *i)
 {
-        struct dlm_cluster *cl = to_cluster(i);
+        struct dlm_cluster *cl = config_item_to_cluster(i);
         struct config_item *tmp;
         int j;
 
@@ -468,7 +471,7 @@ static void drop_cluster(struct config_group *g, struct config_item *i)
 
 static void release_cluster(struct config_item *i)
 {
-        struct dlm_cluster *cl = to_cluster(i);
+        struct dlm_cluster *cl = config_item_to_cluster(i);
         kfree(cl->group.default_groups);
         kfree(cl);
 }
@@ -507,7 +510,7 @@ static struct config_group *make_space(struct config_group *g, const char *name)
 
 static void drop_space(struct config_group *g, struct config_item *i)
 {
-        struct dlm_space *sp = to_space(i);
+        struct dlm_space *sp = config_item_to_space(i);
         struct config_item *tmp;
         int j;
 
@@ -524,7 +527,7 @@ static void drop_space(struct config_group *g, struct config_item *i)
 
 static void release_space(struct config_item *i)
 {
-        struct dlm_space *sp = to_space(i);
+        struct dlm_space *sp = config_item_to_space(i);
         kfree(sp->group.default_groups);
         kfree(sp);
 }
@@ -546,7 +549,7 @@ static struct config_item *make_comm(struct config_group *g, const char *name)
 
 static void drop_comm(struct config_group *g, struct config_item *i)
 {
-        struct dlm_comm *cm = to_comm(i);
+        struct dlm_comm *cm = config_item_to_comm(i);
         if (local_comm == cm)
                 local_comm = NULL;
         dlm_lowcomms_close(cm->nodeid);
@@ -557,13 +560,13 @@ static void drop_comm(struct config_group *g, struct config_item *i)
 
 static void release_comm(struct config_item *i)
 {
-        struct dlm_comm *cm = to_comm(i);
+        struct dlm_comm *cm = config_item_to_comm(i);
         kfree(cm);
 }
 
 static struct config_item *make_node(struct config_group *g, const char *name)
 {
-        struct dlm_space *sp = to_space(g->cg_item.ci_parent);
+        struct dlm_space *sp = config_item_to_space(g->cg_item.ci_parent);
         struct dlm_node *nd;
 
         nd = kzalloc(sizeof(struct dlm_node), GFP_KERNEL);
@@ -585,8 +588,8 @@ static struct config_item *make_node(struct config_group *g, const char *name)
 
 static void drop_node(struct config_group *g, struct config_item *i)
 {
-        struct dlm_space *sp = to_space(g->cg_item.ci_parent);
-        struct dlm_node *nd = to_node(i);
+        struct dlm_space *sp = config_item_to_space(g->cg_item.ci_parent);
+        struct dlm_node *nd = config_item_to_node(i);
 
         mutex_lock(&sp->members_lock);
         list_del(&nd->list);
@@ -598,7 +601,7 @@ static void drop_node(struct config_group *g, struct config_item *i)
 
 static void release_node(struct config_item *i)
 {
-        struct dlm_node *nd = to_node(i);
+        struct dlm_node *nd = config_item_to_node(i);
         kfree(nd);
 }
 
@@ -632,7 +635,7 @@ void dlm_config_exit(void)
 static ssize_t show_cluster(struct config_item *i, struct configfs_attribute *a,
                             char *buf)
 {
-        struct dlm_cluster *cl = to_cluster(i);
+        struct dlm_cluster *cl = config_item_to_cluster(i);
         struct cluster_attribute *cla =
                         container_of(a, struct cluster_attribute, attr);
         return cla->show ? cla->show(cl, buf) : 0;
@@ -642,7 +645,7 @@ static ssize_t store_cluster(struct config_item *i,
                              struct configfs_attribute *a,
                              const char *buf, size_t len)
 {
-        struct dlm_cluster *cl = to_cluster(i);
+        struct dlm_cluster *cl = config_item_to_cluster(i);
         struct cluster_attribute *cla =
                 container_of(a, struct cluster_attribute, attr);
         return cla->store ? cla->store(cl, buf, len) : -EINVAL;
@@ -651,7 +654,7 @@ static ssize_t store_cluster(struct config_item *i,
 static ssize_t show_comm(struct config_item *i, struct configfs_attribute *a,
                          char *buf)
 {
-        struct dlm_comm *cm = to_comm(i);
+        struct dlm_comm *cm = config_item_to_comm(i);
         struct comm_attribute *cma =
                         container_of(a, struct comm_attribute, attr);
         return cma->show ? cma->show(cm, buf) : 0;
@@ -660,7 +663,7 @@ static ssize_t show_comm(struct config_item *i, struct configfs_attribute *a,
 static ssize_t store_comm(struct config_item *i, struct configfs_attribute *a,
                           const char *buf, size_t len)
 {
-        struct dlm_comm *cm = to_comm(i);
+        struct dlm_comm *cm = config_item_to_comm(i);
         struct comm_attribute *cma =
                 container_of(a, struct comm_attribute, attr);
         return cma->store ? cma->store(cm, buf, len) : -EINVAL;
@@ -714,7 +717,7 @@ static ssize_t comm_addr_write(struct dlm_comm *cm, const char *buf, size_t len)
 static ssize_t show_node(struct config_item *i, struct configfs_attribute *a,
                          char *buf)
 {
-        struct dlm_node *nd = to_node(i);
+        struct dlm_node *nd = config_item_to_node(i);
         struct node_attribute *nda =
                         container_of(a, struct node_attribute, attr);
         return nda->show ? nda->show(nd, buf) : 0;
@@ -723,7 +726,7 @@ static ssize_t show_node(struct config_item *i, struct configfs_attribute *a,
 static ssize_t store_node(struct config_item *i, struct configfs_attribute *a,
                           const char *buf, size_t len)
 {
-        struct dlm_node *nd = to_node(i);
+        struct dlm_node *nd = config_item_to_node(i);
         struct node_attribute *nda =
                 container_of(a, struct node_attribute, attr);
         return nda->store ? nda->store(nd, buf, len) : -EINVAL;
@@ -768,7 +771,7 @@ static struct dlm_space *get_space(char *name)
         i = config_group_find_item(space_list, name);
         mutex_unlock(&space_list->cg_subsys->su_mutex);
 
-        return to_space(i);
+        return config_item_to_space(i);
 }
 
 static void put_space(struct dlm_space *sp)
@@ -776,6 +779,33 @@ static void put_space(struct dlm_space *sp)
         config_item_put(&sp->group.cg_item);
 }
 
+static int addr_compare(struct sockaddr_storage *x, struct sockaddr_storage *y)
+{
+        switch (x->ss_family) {
+        case AF_INET: {
+                struct sockaddr_in *sinx = (struct sockaddr_in *)x;
+                struct sockaddr_in *siny = (struct sockaddr_in *)y;
+                if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
+                        return 0;
+                if (sinx->sin_port != siny->sin_port)
+                        return 0;
+                break;
+        }
+        case AF_INET6: {
+                struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
+                struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
+                if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
+                        return 0;
+                if (sinx->sin6_port != siny->sin6_port)
+                        return 0;
+                break;
+        }
+        default:
+                return 0;
+        }
+        return 1;
+}
+
 static struct dlm_comm *get_comm(int nodeid, struct sockaddr_storage *addr)
 {
         struct config_item *i;
@@ -788,7 +818,7 @@ static struct dlm_comm *get_comm(int nodeid, struct sockaddr_storage *addr)
         mutex_lock(&clusters_root.subsys.su_mutex);
 
         list_for_each_entry(i, &comm_list->cg_children, ci_entry) {
-                cm = to_comm(i);
+                cm = config_item_to_comm(i);
 
                 if (nodeid) {
                         if (cm->nodeid != nodeid)
@@ -797,8 +827,7 @@ static struct dlm_comm *get_comm(int nodeid, struct sockaddr_storage *addr)
                         config_item_get(i);
                         break;
                 } else {
-                        if (!cm->addr_count ||
-                            memcmp(cm->addr[0], addr, sizeof(*addr)))
+                        if (!cm->addr_count || !addr_compare(cm->addr[0], addr))
                                 continue;
                         found = 1;
                         config_item_get(i);
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 5a7ac33b629c..868e4c9ef127 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -2,7 +2,7 @@
 *******************************************************************************
 **
 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
-**  Copyright (C) 2004-2007 Red Hat, Inc.  All rights reserved.
+**  Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
 **
 **  This copyrighted material is made available to anyone wishing to use,
 **  modify, copy, or redistribute it subject to the terms and conditions
@@ -441,8 +441,11 @@ struct dlm_ls {
         uint32_t                ls_global_id;   /* global unique lockspace ID */
         uint32_t                ls_exflags;
         int                     ls_lvblen;
-        int                     ls_count;       /* reference count */
+        int                     ls_count;       /* refcount of processes in
+                                                   the dlm using this ls */
+        int                     ls_create_count; /* create/release refcount */
         unsigned long           ls_flags;       /* LSFL_ */
+        unsigned long           ls_scan_time;
         struct kobject          ls_kobj;
 
         struct dlm_rsbtable     *ls_rsbtbl;
diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index 499e16759e96..d910501de6d2 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -2,7 +2,7 @@
 *******************************************************************************
 **
 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
-**  Copyright (C) 2004-2007 Red Hat, Inc.  All rights reserved.
+**  Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
 **
 **  This copyrighted material is made available to anyone wishing to use,
 **  modify, copy, or redistribute it subject to the terms and conditions
@@ -23,6 +23,7 @@
 #include "lock.h"
 #include "recover.h"
 #include "requestqueue.h"
+#include "user.h"
 
 static int                      ls_count;
 static struct mutex             ls_lock;
@@ -211,19 +212,41 @@ void dlm_lockspace_exit(void)
         kset_unregister(dlm_kset);
 }
 
+static struct dlm_ls *find_ls_to_scan(void)
+{
+        struct dlm_ls *ls;
+
+        spin_lock(&lslist_lock);
+        list_for_each_entry(ls, &lslist, ls_list) {
+                if (time_after_eq(jiffies, ls->ls_scan_time +
+                                            dlm_config.ci_scan_secs * HZ)) {
+                        spin_unlock(&lslist_lock);
+                        return ls;
+                }
+        }
+        spin_unlock(&lslist_lock);
+        return NULL;
+}
+
 static int dlm_scand(void *data)
 {
         struct dlm_ls *ls;
+        int timeout_jiffies = dlm_config.ci_scan_secs * HZ;
 
         while (!kthread_should_stop()) {
-                list_for_each_entry(ls, &lslist, ls_list) {
+                ls = find_ls_to_scan();
+                if (ls) {
                         if (dlm_lock_recovery_try(ls)) {
+                                ls->ls_scan_time = jiffies;
                                 dlm_scan_rsbs(ls);
                                 dlm_scan_timeout(ls);
                                 dlm_unlock_recovery(ls);
+                        } else {
+                                ls->ls_scan_time += HZ;
                         }
+                } else {
+                        schedule_timeout_interruptible(timeout_jiffies);
                 }
-                schedule_timeout_interruptible(dlm_config.ci_scan_secs * HZ);
         }
         return 0;
 }
@@ -246,23 +269,6 @@ static void dlm_scand_stop(void)
         kthread_stop(scand_task);
 }
 
-static struct dlm_ls *dlm_find_lockspace_name(char *name, int namelen)
-{
-        struct dlm_ls *ls;
-
-        spin_lock(&lslist_lock);
-
-        list_for_each_entry(ls, &lslist, ls_list) {
-                if (ls->ls_namelen == namelen &&
-                    memcmp(ls->ls_name, name, namelen) == 0)
-                        goto out;
-        }
-        ls = NULL;
- out:
-        spin_unlock(&lslist_lock);
-        return ls;
-}
-
 struct dlm_ls *dlm_find_lockspace_global(uint32_t id)
 {
         struct dlm_ls *ls;
@@ -327,6 +333,7 @@ static void remove_lockspace(struct dlm_ls *ls)
         for (;;) {
                 spin_lock(&lslist_lock);
                 if (ls->ls_count == 0) {
+                        WARN_ON(ls->ls_create_count != 0);
                         list_del(&ls->ls_list);
                         spin_unlock(&lslist_lock);
                         return;
@@ -381,7 +388,7 @@ static int new_lockspace(char *name, int namelen, void **lockspace,
                          uint32_t flags, int lvblen)
 {
         struct dlm_ls *ls;
-        int i, size, error = -ENOMEM;
+        int i, size, error;
         int do_unreg = 0;
 
         if (namelen > DLM_LOCKSPACE_LEN)
@@ -393,12 +400,37 @@ static int new_lockspace(char *name, int namelen, void **lockspace,
         if (!try_module_get(THIS_MODULE))
                 return -EINVAL;
 
-        ls = dlm_find_lockspace_name(name, namelen);
-        if (ls) {
-                *lockspace = ls;
+        if (!dlm_user_daemon_available()) {
+                module_put(THIS_MODULE);
+                return -EUNATCH;
+        }
+
+        error = 0;
+
+        spin_lock(&lslist_lock);
+        list_for_each_entry(ls, &lslist, ls_list) {
+                WARN_ON(ls->ls_create_count <= 0);
+                if (ls->ls_namelen != namelen)
+                        continue;
+                if (memcmp(ls->ls_name, name, namelen))
+                        continue;
+                if (flags & DLM_LSFL_NEWEXCL) {
+                        error = -EEXIST;
+                        break;
+                }
+                ls->ls_create_count++;
                 module_put(THIS_MODULE);
-                return -EEXIST;
+                error = 1; /* not an error, return 0 */
+                break;
         }
+        spin_unlock(&lslist_lock);
+
+        if (error < 0)
+                goto out;
+        if (error)
+                goto ret_zero;
+
+        error = -ENOMEM;
 
         ls = kzalloc(sizeof(struct dlm_ls) + namelen, GFP_KERNEL);
         if (!ls)
@@ -408,6 +440,7 @@ static int new_lockspace(char *name, int namelen, void **lockspace,
         ls->ls_lvblen = lvblen;
         ls->ls_count = 0;
         ls->ls_flags = 0;
+        ls->ls_scan_time = jiffies;
 
         if (flags & DLM_LSFL_TIMEWARN)
                 set_bit(LSFL_TIMEWARN, &ls->ls_flags);
@@ -418,8 +451,9 @@ static int new_lockspace(char *name, int namelen, void **lockspace,
                 ls->ls_allocation = GFP_KERNEL;
 
         /* ls_exflags are forced to match among nodes, and we don't
-           need to require all nodes to have TIMEWARN or FS set */
-        ls->ls_exflags = (flags & ~(DLM_LSFL_TIMEWARN | DLM_LSFL_FS));
+           need to require all nodes to have some flags set */
+        ls->ls_exflags = (flags & ~(DLM_LSFL_TIMEWARN | DLM_LSFL_FS |
+                                    DLM_LSFL_NEWEXCL));
 
         size = dlm_config.ci_rsbtbl_size;
         ls->ls_rsbtbl_size = size;
@@ -510,6 +544,7 @@ static int new_lockspace(char *name, int namelen, void **lockspace,
         down_write(&ls->ls_in_recovery);
 
         spin_lock(&lslist_lock);
+        ls->ls_create_count = 1;
         list_add(&ls->ls_list, &lslist);
         spin_unlock(&lslist_lock);
 
@@ -548,7 +583,7 @@ static int new_lockspace(char *name, int namelen, void **lockspace,
         dlm_create_debug_file(ls);
 
         log_debug(ls, "join complete");
-
+ ret_zero:
         *lockspace = ls;
         return 0;
 
@@ -635,13 +670,34 @@ static int release_lockspace(struct dlm_ls *ls, int force)
         struct dlm_lkb *lkb;
         struct dlm_rsb *rsb;
         struct list_head *head;
-        int i;
-        int busy = lockspace_busy(ls);
+        int i, busy, rv;
+
+        busy = lockspace_busy(ls);
+
+        spin_lock(&lslist_lock);
+        if (ls->ls_create_count == 1) {
+                if (busy > force)
+                        rv = -EBUSY;
+                else {
+                        /* remove_lockspace takes ls off lslist */
+                        ls->ls_create_count = 0;
+                        rv = 0;
+                }
+        } else if (ls->ls_create_count > 1) {
+                rv = --ls->ls_create_count;
+        } else {
+                rv = -EINVAL;
+        }
+        spin_unlock(&lslist_lock);
 
-        if (busy > force)
-                return -EBUSY;
+        if (rv) {
+                log_debug(ls, "release_lockspace no remove %d", rv);
+                return rv;
+        }
+
+        dlm_device_deregister(ls);
 
-        if (force < 3)
+        if (force < 3 && dlm_user_daemon_available())
                 do_uevent(ls, 0);
 
         dlm_recoverd_stop(ls);
@@ -720,15 +776,10 @@ static int release_lockspace(struct dlm_ls *ls, int force)
         dlm_clear_members(ls);
         dlm_clear_members_gone(ls);
         kfree(ls->ls_node_array);
+        log_debug(ls, "release_lockspace final free");
         kobject_put(&ls->ls_kobj);
         /* The ls structure will be freed when the kobject is done with */
 
-        mutex_lock(&ls_lock);
-        ls_count--;
-        if (!ls_count)
-                threads_stop();
-        mutex_unlock(&ls_lock);
-
         module_put(THIS_MODULE);
         return 0;
 }
@@ -750,11 +801,38 @@ static int release_lockspace(struct dlm_ls *ls, int force)
 int dlm_release_lockspace(void *lockspace, int force)
 {
         struct dlm_ls *ls;
+        int error;
 
         ls = dlm_find_lockspace_local(lockspace);
         if (!ls)
                 return -EINVAL;
         dlm_put_lockspace(ls);
-        return release_lockspace(ls, force);
+
+        mutex_lock(&ls_lock);
+        error = release_lockspace(ls, force);
+        if (!error)
+                ls_count--;
+        else if (!ls_count)
+                threads_stop();
+        mutex_unlock(&ls_lock);
+
+        return error;
+}
+
+void dlm_stop_lockspaces(void)
+{
+        struct dlm_ls *ls;
+
+ restart:
+        spin_lock(&lslist_lock);
+        list_for_each_entry(ls, &lslist, ls_list) {
+                if (!test_bit(LSFL_RUNNING, &ls->ls_flags))
+                        continue;
+                spin_unlock(&lslist_lock);
+                log_error(ls, "no userland control daemon, stopping lockspace");
+                dlm_ls_stop(ls);
+                goto restart;
+        }
+        spin_unlock(&lslist_lock);
 }
 
diff --git a/fs/dlm/lockspace.h b/fs/dlm/lockspace.h
index 891eabbdd021..f879f87901f8 100644
--- a/fs/dlm/lockspace.h
+++ b/fs/dlm/lockspace.h
@@ -20,6 +20,7 @@ struct dlm_ls *dlm_find_lockspace_global(uint32_t id);
 struct dlm_ls *dlm_find_lockspace_local(void *id);
 struct dlm_ls *dlm_find_lockspace_device(int minor);
 void dlm_put_lockspace(struct dlm_ls *ls);
+void dlm_stop_lockspaces(void);
 
 #endif                          /* __LOCKSPACE_DOT_H__ */
 
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index 34f14a14fb4e..b3832c67194a 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2007 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2006-2008 Red Hat, Inc.  All rights reserved.
  *
  * This copyrighted material is made available to anyone wishing to use,
  * modify, copy, or redistribute it subject to the terms and conditions
@@ -15,7 +15,6 @@
 #include <linux/poll.h>
 #include <linux/signal.h>
 #include <linux/spinlock.h>
-#include <linux/smp_lock.h>
 #include <linux/dlm.h>
 #include <linux/dlm_device.h>
 
@@ -27,6 +26,8 @@
 
 static const char name_prefix[] = "dlm";
 static const struct file_operations device_fops;
+static atomic_t dlm_monitor_opened;
+static int dlm_monitor_unused = 1;
 
 #ifdef CONFIG_COMPAT
 
@@ -340,10 +341,15 @@ static int device_user_deadlock(struct dlm_user_proc *proc,
         return error;
 }
 
-static int create_misc_device(struct dlm_ls *ls, char *name)
+static int dlm_device_register(struct dlm_ls *ls, char *name)
 {
         int error, len;
 
+        /* The device is already registered.  This happens when the
+           lockspace is created multiple times from userspace. */
+        if (ls->ls_device.name)
+                return 0;
+
         error = -ENOMEM;
         len = strlen(name) + strlen(name_prefix) + 2;
         ls->ls_device.name = kzalloc(len, GFP_KERNEL);
@@ -363,6 +369,22 @@ fail:
         return error;
 }
 
+int dlm_device_deregister(struct dlm_ls *ls)
+{
+        int error;
+
+        /* The device is not registered.  This happens when the lockspace
+           was never used from userspace, or when device_create_lockspace()
+           calls dlm_release_lockspace() after the register fails. */
+        if (!ls->ls_device.name)
+                return 0;
+
+        error = misc_deregister(&ls->ls_device);
+        if (!error)
+                kfree(ls->ls_device.name);
+        return error;
+}
+
 static int device_user_purge(struct dlm_user_proc *proc,
                              struct dlm_purge_params *params)
 {
@@ -397,7 +419,7 @@ static int device_create_lockspace(struct dlm_lspace_params *params)
         if (!ls)
                 return -ENOENT;
 
-        error = create_misc_device(ls, params->name);
+        error = dlm_device_register(ls, params->name);
         dlm_put_lockspace(ls);
 
         if (error)
@@ -421,31 +443,22 @@ static int device_remove_lockspace(struct dlm_lspace_params *params)
         if (!ls)
                 return -ENOENT;
 
-        /* Deregister the misc device first, so we don't have
-         * a device that's not attached to a lockspace. If
-         * dlm_release_lockspace fails then we can recreate it
-         */
-        error = misc_deregister(&ls->ls_device);
-        if (error) {
-                dlm_put_lockspace(ls);
-                goto out;
-        }
-        kfree(ls->ls_device.name);
-
         if (params->flags & DLM_USER_LSFLG_FORCEFREE)
                 force = 2;
 
         lockspace = ls->ls_local_handle;
+        dlm_put_lockspace(ls);
 
-        /* dlm_release_lockspace waits for references to go to zero,
-           so all processes will need to close their device for the ls
-           before the release will procede */
+        /* The final dlm_release_lockspace waits for references to go to
+           zero, so all processes will need to close their device for the
+           ls before the release will proceed.  release also calls the
+           device_deregister above.  Converting a positive return value
+           from release to zero means that userspace won't know when its
+           release was the final one, but it shouldn't need to know. */
 
-        dlm_put_lockspace(ls);
         error = dlm_release_lockspace(lockspace, force);
-        if (error)
-                create_misc_device(ls, ls->ls_name);
- out:
+        if (error > 0)
+                error = 0;
         return error;
 }
 
@@ -623,17 +636,13 @@ static int device_open(struct inode *inode, struct file *file)
         struct dlm_user_proc *proc;
         struct dlm_ls *ls;
 
-        lock_kernel();
         ls = dlm_find_lockspace_device(iminor(inode));
-        if (!ls) {
-                unlock_kernel();
+        if (!ls)
                 return -ENOENT;
-        }
 
         proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
         if (!proc) {
                 dlm_put_lockspace(ls);
-                unlock_kernel();
                 return -ENOMEM;
         }
 
@@ -645,7 +654,6 @@ static int device_open(struct inode *inode, struct file *file)
         spin_lock_init(&proc->locks_spin);
         init_waitqueue_head(&proc->wait);
         file->private_data = proc;
-        unlock_kernel();
 
         return 0;
 }
@@ -878,9 +886,28 @@ static unsigned int device_poll(struct file *file, poll_table *wait)
         return 0;
 }
 
+int dlm_user_daemon_available(void)
+{
+        /* dlm_controld hasn't started (or, has started, but not
+           properly populated configfs) */
+
+        if (!dlm_our_nodeid())
+                return 0;
+
+        /* This is to deal with versions of dlm_controld that don't
+           know about the monitor device.  We assume that if the
+           dlm_controld was started (above), but the monitor device
+           was never opened, that it's an old version.  dlm_controld
+           should open the monitor device before populating configfs. */
+
+        if (dlm_monitor_unused)
+                return 1;
+
+        return atomic_read(&dlm_monitor_opened) ? 1 : 0;
+}
+
 static int ctl_device_open(struct inode *inode, struct file *file)
 {
-        cycle_kernel_lock();
         file->private_data = NULL;
         return 0;
 }
@@ -890,6 +917,20 @@ static int ctl_device_close(struct inode *inode, struct file *file)
         return 0;
 }
 
+static int monitor_device_open(struct inode *inode, struct file *file)
+{
+        atomic_inc(&dlm_monitor_opened);
+        dlm_monitor_unused = 0;
+        return 0;
+}
+
+static int monitor_device_close(struct inode *inode, struct file *file)
+{
+        if (atomic_dec_and_test(&dlm_monitor_opened))
+                dlm_stop_lockspaces();
+        return 0;
+}
+
 static const struct file_operations device_fops = {
         .open    = device_open,
         .release = device_close,
@@ -913,19 +954,42 @@ static struct miscdevice ctl_device = {
         .minor = MISC_DYNAMIC_MINOR,
 };
 
+static const struct file_operations monitor_device_fops = {
+        .open    = monitor_device_open,
+        .release = monitor_device_close,
+        .owner   = THIS_MODULE,
+};
+
+static struct miscdevice monitor_device = {
+        .name  = "dlm-monitor",
+        .fops  = &monitor_device_fops,
+        .minor = MISC_DYNAMIC_MINOR,
+};
+
 int __init dlm_user_init(void)
 {
         int error;
 
+        atomic_set(&dlm_monitor_opened, 0);
+
         error = misc_register(&ctl_device);
-        if (error)
+        if (error) {
                 log_print("misc_register failed for control device");
+                goto out;
+        }
 
+        error = misc_register(&monitor_device);
+        if (error) {
+                log_print("misc_register failed for monitor device");
+                misc_deregister(&ctl_device);
+        }
+ out:
         return error;
 }
 
 void dlm_user_exit(void)
 {
         misc_deregister(&ctl_device);
+        misc_deregister(&monitor_device);
 }
 
diff --git a/fs/dlm/user.h b/fs/dlm/user.h
index d38e9f3e4151..35eb6a13d616 100644
--- a/fs/dlm/user.h
+++ b/fs/dlm/user.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2006-2008 Red Hat, Inc.  All rights reserved.
  *
  * This copyrighted material is made available to anyone wishing to use,
  * modify, copy, or redistribute it subject to the terms and conditions
@@ -12,5 +12,7 @@
 void dlm_user_add_ast(struct dlm_lkb *lkb, int type);
 int dlm_user_init(void);
 void dlm_user_exit(void);
+int dlm_device_deregister(struct dlm_ls *ls);
+int dlm_user_daemon_available(void);
 
 #endif
diff --git a/fs/gfs2/locking/dlm/mount.c b/fs/gfs2/locking/dlm/mount.c
index 09d78c216f48..0c4cbe6c8285 100644
--- a/fs/gfs2/locking/dlm/mount.c
+++ b/fs/gfs2/locking/dlm/mount.c
@@ -144,7 +144,8 @@ static int gdlm_mount(char *table_name, char *host_data,
 
         error = dlm_new_lockspace(ls->fsname, strlen(ls->fsname),
                                   &ls->dlm_lockspace,
-                                  DLM_LSFL_FS | (nodir ? DLM_LSFL_NODIR : 0),
+                                  DLM_LSFL_FS | DLM_LSFL_NEWEXCL |
+                                  (nodir ? DLM_LSFL_NODIR : 0),
                                   GDLM_LVB_SIZE);
         if (error) {
                 log_error("dlm_new_lockspace error %d", error);