Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 841 insertions, 0 deletions

diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
new file mode 100644
index 000000000..a9c98b4f3
--- /dev/null
+++ b/fs/dlm/lockspace.c
@@ -0,0 +1,841 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2011 Red Hat, Inc.  All rights reserved.
+**
+**
+*******************************************************************************
+******************************************************************************/
+
+#include <linux/module.h>
+
+#include "dlm_internal.h"
+#include "lockspace.h"
+#include "member.h"
+#include "recoverd.h"
+#include "dir.h"
+#include "midcomms.h"
+#include "config.h"
+#include "memory.h"
+#include "lock.h"
+#include "recover.h"
+#include "requestqueue.h"
+#include "user.h"
+#include "ast.h"
+
+static int			ls_count;
+static struct mutex		ls_lock;
+static struct list_head		lslist;
+static spinlock_t		lslist_lock;
+
+static ssize_t dlm_control_store(struct dlm_ls *ls, const char *buf, size_t len)
+{
+	ssize_t ret = len;
+	int n;
+	int rc = kstrtoint(buf, 0, &n);
+
+	if (rc)
+		return rc;
+	ls = dlm_find_lockspace_local(ls);
+	if (!ls)
+		return -EINVAL;
+
+	switch (n) {
+	case 0:
+		dlm_ls_stop(ls);
+		break;
+	case 1:
+		dlm_ls_start(ls);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	dlm_put_lockspace(ls);
+	return ret;
+}
+
+static ssize_t dlm_event_store(struct dlm_ls *ls, const char *buf, size_t len)
+{
+	int rc = kstrtoint(buf, 0, &ls->ls_uevent_result);
+
+	if (rc)
+		return rc;
+	set_bit(LSFL_UEVENT_WAIT, &ls->ls_flags);
+	wake_up(&ls->ls_uevent_wait);
+	return len;
+}
+
+static ssize_t dlm_id_show(struct dlm_ls *ls, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%u\n", ls->ls_global_id);
+}
+
+static ssize_t dlm_id_store(struct dlm_ls *ls, const char *buf, size_t len)
+{
+	int rc = kstrtouint(buf, 0, &ls->ls_global_id);
+
+	if (rc)
+		return rc;
+	return len;
+}
+
+static ssize_t dlm_nodir_show(struct dlm_ls *ls, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%u\n", dlm_no_directory(ls));
+}
+
+static ssize_t dlm_nodir_store(struct dlm_ls *ls, const char *buf, size_t len)
+{
+	int val;
+	int rc = kstrtoint(buf, 0, &val);
+
+	if (rc)
+		return rc;
+	if (val == 1)
+		set_bit(LSFL_NODIR, &ls->ls_flags);
+	return len;
+}
+
+static ssize_t dlm_recover_status_show(struct dlm_ls *ls, char *buf)
+{
+	uint32_t status = dlm_recover_status(ls);
+	return snprintf(buf, PAGE_SIZE, "%x\n", status);
+}
+
+static ssize_t dlm_recover_nodeid_show(struct dlm_ls *ls, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", ls->ls_recover_nodeid);
+}
+
+struct dlm_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct dlm_ls *, char *);
+	ssize_t (*store)(struct dlm_ls *, const char *, size_t);
+};
+
+static struct dlm_attr dlm_attr_control = {
+	.attr  = {.name = "control", .mode = S_IWUSR},
+	.store = dlm_control_store
+};
+
+static struct dlm_attr dlm_attr_event = {
+	.attr  = {.name = "event_done", .mode = S_IWUSR},
+	.store = dlm_event_store
+};
+
+static struct dlm_attr dlm_attr_id = {
+	.attr  = {.name = "id", .mode = S_IRUGO | S_IWUSR},
+	.show  = dlm_id_show,
+	.store = dlm_id_store
+};
+
+static struct dlm_attr dlm_attr_nodir = {
+	.attr  = {.name = "nodir", .mode = S_IRUGO | S_IWUSR},
+	.show  = dlm_nodir_show,
+	.store = dlm_nodir_store
+};
+
+static struct dlm_attr dlm_attr_recover_status = {
+	.attr  = {.name = "recover_status", .mode = S_IRUGO},
+	.show  = dlm_recover_status_show
+};
+
+static struct dlm_attr dlm_attr_recover_nodeid = {
+	.attr  = {.name = "recover_nodeid", .mode = S_IRUGO},
+	.show  = dlm_recover_nodeid_show
+};
+
+static struct attribute *dlm_attrs[] = {
+	&dlm_attr_control.attr,
+	&dlm_attr_event.attr,
+	&dlm_attr_id.attr,
+	&dlm_attr_nodir.attr,
+	&dlm_attr_recover_status.attr,
+	&dlm_attr_recover_nodeid.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(dlm);
+
+static ssize_t dlm_attr_show(struct kobject *kobj, struct attribute *attr,
+			     char *buf)
+{
+	struct dlm_ls *ls  = container_of(kobj, struct dlm_ls, ls_kobj);
+	struct dlm_attr *a = container_of(attr, struct dlm_attr, attr);
+	return a->show ? a->show(ls, buf) : 0;
+}
+
+static ssize_t dlm_attr_store(struct kobject *kobj, struct attribute *attr,
+			      const char *buf, size_t len)
+{
+	struct dlm_ls *ls  = container_of(kobj, struct dlm_ls, ls_kobj);
+	struct dlm_attr *a = container_of(attr, struct dlm_attr, attr);
+	return a->store ? a->store(ls, buf, len) : len;
+}
+
+static const struct sysfs_ops dlm_attr_ops = {
+	.show  = dlm_attr_show,
+	.store = dlm_attr_store,
+};
+
+static struct kobj_type dlm_ktype = {
+	.default_groups = dlm_groups,
+	.sysfs_ops     = &dlm_attr_ops,
+};
+
+static struct kset *dlm_kset;
+
+static int do_uevent(struct dlm_ls *ls, int in, unsigned int release_recover)
+{
+	char message[512] = {};
+	char *envp[] = { message, NULL };
+
+	if (in) {
+		kobject_uevent(&ls->ls_kobj, KOBJ_ONLINE);
+	} else {
+		snprintf(message, 511, "RELEASE_RECOVER=%u", release_recover);
+		kobject_uevent_env(&ls->ls_kobj, KOBJ_OFFLINE, envp);
+	}
+
+	log_rinfo(ls, "%s the lockspace group...", in ? "joining" : "leaving");
+
+	/* dlm_controld will see the uevent, do the necessary group management
+	   and then write to sysfs to wake us */
+
+	wait_event(ls->ls_uevent_wait,
+		   test_and_clear_bit(LSFL_UEVENT_WAIT, &ls->ls_flags));
+
+	log_rinfo(ls, "group event done %d", ls->ls_uevent_result);
+
+	return ls->ls_uevent_result;
+}
+
+static int dlm_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
+{
+	const struct dlm_ls *ls = container_of(kobj, struct dlm_ls, ls_kobj);
+
+	add_uevent_var(env, "LOCKSPACE=%s", ls->ls_name);
+	return 0;
+}
+
+static const struct kset_uevent_ops dlm_uevent_ops = {
+	.uevent = dlm_uevent,
+};
+
+int __init dlm_lockspace_init(void)
+{
+	ls_count = 0;
+	mutex_init(&ls_lock);
+	INIT_LIST_HEAD(&lslist);
+	spin_lock_init(&lslist_lock);
+
+	dlm_kset = kset_create_and_add("dlm", &dlm_uevent_ops, kernel_kobj);
+	if (!dlm_kset) {
+		printk(KERN_WARNING "%s: can not create kset\n", __func__);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+void dlm_lockspace_exit(void)
+{
+	kset_unregister(dlm_kset);
+}
+
+struct dlm_ls *dlm_find_lockspace_global(uint32_t id)
+{
+	struct dlm_ls *ls;
+
+	spin_lock_bh(&lslist_lock);
+
+	list_for_each_entry(ls, &lslist, ls_list) {
+		if (ls->ls_global_id == id) {
+			atomic_inc(&ls->ls_count);
+			goto out;
+		}
+	}
+	ls = NULL;
+ out:
+	spin_unlock_bh(&lslist_lock);
+	return ls;
+}
+
+struct dlm_ls *dlm_find_lockspace_local(dlm_lockspace_t *lockspace)
+{
+	struct dlm_ls *ls = lockspace;
+
+	atomic_inc(&ls->ls_count);
+	return ls;
+}
+
+struct dlm_ls *dlm_find_lockspace_device(int minor)
+{
+	struct dlm_ls *ls;
+
+	spin_lock_bh(&lslist_lock);
+	list_for_each_entry(ls, &lslist, ls_list) {
+		if (ls->ls_device.minor == minor) {
+			atomic_inc(&ls->ls_count);
+			goto out;
+		}
+	}
+	ls = NULL;
+ out:
+	spin_unlock_bh(&lslist_lock);
+	return ls;
+}
+
+void dlm_put_lockspace(struct dlm_ls *ls)
+{
+	if (atomic_dec_and_test(&ls->ls_count))
+		wake_up(&ls->ls_count_wait);
+}
+
+static void remove_lockspace(struct dlm_ls *ls)
+{
+retry:
+	wait_event(ls->ls_count_wait, atomic_read(&ls->ls_count) == 0);
+
+	spin_lock_bh(&lslist_lock);
+	if (atomic_read(&ls->ls_count) != 0) {
+		spin_unlock_bh(&lslist_lock);
+		goto retry;
+	}
+
+	WARN_ON(ls->ls_create_count != 0);
+	list_del(&ls->ls_list);
+	spin_unlock_bh(&lslist_lock);
+}
+
+static int threads_start(void)
+{
+	int error;
+
+	/* Thread for sending/receiving messages for all lockspace's */
+	error = dlm_midcomms_start();
+	if (error)
+		log_print("cannot start dlm midcomms %d", error);
+
+	return error;
+}
+
+static int lkb_idr_free(struct dlm_lkb *lkb)
+{
+	if (lkb->lkb_lvbptr && test_bit(DLM_IFL_MSTCPY_BIT, &lkb->lkb_iflags))
+		dlm_free_lvb(lkb->lkb_lvbptr);
+
+	dlm_free_lkb(lkb);
+	return 0;
+}
+
+static void rhash_free_rsb(void *ptr, void *arg)
+{
+	struct dlm_rsb *rsb = ptr;
+
+	dlm_free_rsb(rsb);
+}
+
+static void free_lockspace(struct work_struct *work)
+{
+	struct dlm_ls *ls  = container_of(work, struct dlm_ls, ls_free_work);
+	struct dlm_lkb *lkb;
+	unsigned long id;
+
+	/*
+	 * Free all lkb's in xa
+	 */
+	xa_for_each(&ls->ls_lkbxa, id, lkb) {
+		lkb_idr_free(lkb);
+	}
+	xa_destroy(&ls->ls_lkbxa);
+
+	/*
+	 * Free all rsb's on rsbtbl
+	 */
+	rhashtable_free_and_destroy(&ls->ls_rsbtbl, rhash_free_rsb, NULL);
+
+	kfree(ls);
+}
+
+static int new_lockspace(const char *name, const char *cluster,
+			 uint32_t flags, int lvblen,
+			 const struct dlm_lockspace_ops *ops, void *ops_arg,
+			 int *ops_result, dlm_lockspace_t **lockspace)
+{
+	struct dlm_ls *ls;
+	int namelen = strlen(name);
+	int error;
+
+	if (namelen > DLM_LOCKSPACE_LEN || namelen == 0)
+		return -EINVAL;
+
+	if (lvblen % 8)
+		return -EINVAL;
+
+	if (!try_module_get(THIS_MODULE))
+		return -EINVAL;
+
+	if (!dlm_user_daemon_available()) {
+		log_print("dlm user daemon not available");
+		error = -EUNATCH;
+		goto out;
+	}
+
+	if (ops && ops_result) {
+	       	if (!dlm_config.ci_recover_callbacks)
+			*ops_result = -EOPNOTSUPP;
+		else
+			*ops_result = 0;
+	}
+
+	if (!cluster)
+		log_print("dlm cluster name '%s' is being used without an application provided cluster name",
+			  dlm_config.ci_cluster_name);
+
+	if (dlm_config.ci_recover_callbacks && cluster &&
+	    strncmp(cluster, dlm_config.ci_cluster_name, DLM_LOCKSPACE_LEN)) {
+		log_print("dlm cluster name '%s' does not match "
+			  "the application cluster name '%s'",
+			  dlm_config.ci_cluster_name, cluster);
+		error = -EBADR;
+		goto out;
+	}
+
+	error = 0;
+
+	spin_lock_bh(&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++;
+		*lockspace = ls;
+		error = 1;
+		break;
+	}
+	spin_unlock_bh(&lslist_lock);
+
+	if (error)
+		goto out;
+
+	error = -ENOMEM;
+
+	ls = kzalloc_obj(*ls, GFP_NOFS);
+	if (!ls)
+		goto out;
+	memcpy(ls->ls_name, name, namelen);
+	ls->ls_namelen = namelen;
+	ls->ls_lvblen = lvblen;
+	atomic_set(&ls->ls_count, 0);
+	init_waitqueue_head(&ls->ls_count_wait);
+	ls->ls_flags = 0;
+
+	if (ops && dlm_config.ci_recover_callbacks) {
+		ls->ls_ops = ops;
+		ls->ls_ops_arg = ops_arg;
+	}
+
+	if (flags & DLM_LSFL_SOFTIRQ)
+		set_bit(LSFL_SOFTIRQ, &ls->ls_flags);
+
+	/* ls_exflags are forced to match among nodes, and we don't
+	 * need to require all nodes to have some flags set
+	 */
+	ls->ls_exflags = (flags & ~(DLM_LSFL_FS | DLM_LSFL_NEWEXCL |
+				    DLM_LSFL_SOFTIRQ));
+
+	INIT_LIST_HEAD(&ls->ls_slow_inactive);
+	INIT_LIST_HEAD(&ls->ls_slow_active);
+	rwlock_init(&ls->ls_rsbtbl_lock);
+
+	error = rhashtable_init(&ls->ls_rsbtbl, &dlm_rhash_rsb_params);
+	if (error)
+		goto out_lsfree;
+
+	xa_init_flags(&ls->ls_lkbxa, XA_FLAGS_ALLOC | XA_FLAGS_LOCK_BH);
+	rwlock_init(&ls->ls_lkbxa_lock);
+
+	INIT_LIST_HEAD(&ls->ls_waiters);
+	spin_lock_init(&ls->ls_waiters_lock);
+	INIT_LIST_HEAD(&ls->ls_orphans);
+	spin_lock_init(&ls->ls_orphans_lock);
+
+	INIT_LIST_HEAD(&ls->ls_nodes);
+	INIT_LIST_HEAD(&ls->ls_nodes_gone);
+	ls->ls_num_nodes = 0;
+	ls->ls_low_nodeid = 0;
+	ls->ls_total_weight = 0;
+	ls->ls_node_array = NULL;
+
+	memset(&ls->ls_local_rsb, 0, sizeof(struct dlm_rsb));
+	ls->ls_local_rsb.res_ls = ls;
+
+	ls->ls_debug_rsb_dentry = NULL;
+	ls->ls_debug_waiters_dentry = NULL;
+
+	init_waitqueue_head(&ls->ls_uevent_wait);
+	ls->ls_uevent_result = 0;
+	init_completion(&ls->ls_recovery_done);
+	ls->ls_recovery_result = -1;
+
+	spin_lock_init(&ls->ls_cb_lock);
+	INIT_LIST_HEAD(&ls->ls_cb_delay);
+
+	INIT_WORK(&ls->ls_free_work, free_lockspace);
+
+	ls->ls_recoverd_task = NULL;
+	mutex_init(&ls->ls_recoverd_active);
+	spin_lock_init(&ls->ls_recover_lock);
+	spin_lock_init(&ls->ls_rcom_spin);
+	get_random_bytes(&ls->ls_rcom_seq, sizeof(uint64_t));
+	ls->ls_recover_status = 0;
+	ls->ls_recover_seq = get_random_u64();
+	ls->ls_recover_args = NULL;
+	init_rwsem(&ls->ls_in_recovery);
+	rwlock_init(&ls->ls_recv_active);
+	INIT_LIST_HEAD(&ls->ls_requestqueue);
+	rwlock_init(&ls->ls_requestqueue_lock);
+	spin_lock_init(&ls->ls_clear_proc_locks);
+
+	/* Due backwards compatibility with 3.1 we need to use maximum
+	 * possible dlm message size to be sure the message will fit and
+	 * not having out of bounds issues. However on sending side 3.2
+	 * might send less.
+	 */
+	ls->ls_recover_buf = kmalloc(DLM_MAX_SOCKET_BUFSIZE, GFP_NOFS);
+	if (!ls->ls_recover_buf) {
+		error = -ENOMEM;
+		goto out_lkbxa;
+	}
+
+	ls->ls_slot = 0;
+	ls->ls_num_slots = 0;
+	ls->ls_slots_size = 0;
+	ls->ls_slots = NULL;
+
+	INIT_LIST_HEAD(&ls->ls_recover_list);
+	spin_lock_init(&ls->ls_recover_list_lock);
+	xa_init_flags(&ls->ls_recover_xa, XA_FLAGS_ALLOC | XA_FLAGS_LOCK_BH);
+	spin_lock_init(&ls->ls_recover_xa_lock);
+	ls->ls_recover_list_count = 0;
+	init_waitqueue_head(&ls->ls_wait_general);
+	INIT_LIST_HEAD(&ls->ls_masters_list);
+	rwlock_init(&ls->ls_masters_lock);
+	INIT_LIST_HEAD(&ls->ls_dir_dump_list);
+	rwlock_init(&ls->ls_dir_dump_lock);
+
+	INIT_LIST_HEAD(&ls->ls_scan_list);
+	spin_lock_init(&ls->ls_scan_lock);
+	timer_setup(&ls->ls_scan_timer, dlm_rsb_scan, TIMER_DEFERRABLE);
+
+	spin_lock_bh(&lslist_lock);
+	ls->ls_create_count = 1;
+	list_add(&ls->ls_list, &lslist);
+	spin_unlock_bh(&lslist_lock);
+
+	if (flags & DLM_LSFL_FS)
+		set_bit(LSFL_FS, &ls->ls_flags);
+
+	error = dlm_callback_start(ls);
+	if (error) {
+		log_error(ls, "can't start dlm_callback %d", error);
+		goto out_delist;
+	}
+
+	init_waitqueue_head(&ls->ls_recover_lock_wait);
+
+	/*
+	 * Once started, dlm_recoverd first looks for ls in lslist, then
+	 * initializes ls_in_recovery as locked in "down" mode.  We need
+	 * to wait for the wakeup from dlm_recoverd because in_recovery
+	 * has to start out in down mode.
+	 */
+
+	error = dlm_recoverd_start(ls);
+	if (error) {
+		log_error(ls, "can't start dlm_recoverd %d", error);
+		goto out_callback;
+	}
+
+	wait_event(ls->ls_recover_lock_wait,
+		   test_bit(LSFL_RECOVER_LOCK, &ls->ls_flags));
+
+	ls->ls_kobj.kset = dlm_kset;
+	error = kobject_init_and_add(&ls->ls_kobj, &dlm_ktype, NULL,
+				     "%s", ls->ls_name);
+	if (error)
+		goto out_recoverd;
+	kobject_uevent(&ls->ls_kobj, KOBJ_ADD);
+
+	/* This uevent triggers dlm_controld in userspace to add us to the
+	   group of nodes that are members of this lockspace (managed by the
+	   cluster infrastructure.)  Once it's done that, it tells us who the
+	   current lockspace members are (via configfs) and then tells the
+	   lockspace to start running (via sysfs) in dlm_ls_start(). */
+
+	error = do_uevent(ls, 1, 0);
+	if (error < 0)
+		goto out_recoverd;
+
+	/* wait until recovery is successful or failed */
+	wait_for_completion(&ls->ls_recovery_done);
+	error = ls->ls_recovery_result;
+	if (error)
+		goto out_members;
+
+	dlm_create_debug_file(ls);
+
+	log_rinfo(ls, "join complete");
+	*lockspace = ls;
+	return 0;
+
+ out_members:
+	do_uevent(ls, 0, 0);
+	dlm_clear_members(ls);
+	kfree(ls->ls_node_array);
+ out_recoverd:
+	dlm_recoverd_stop(ls);
+ out_callback:
+	dlm_callback_stop(ls);
+ out_delist:
+	spin_lock_bh(&lslist_lock);
+	list_del(&ls->ls_list);
+	spin_unlock_bh(&lslist_lock);
+	xa_destroy(&ls->ls_recover_xa);
+	kfree(ls->ls_recover_buf);
+ out_lkbxa:
+	xa_destroy(&ls->ls_lkbxa);
+	rhashtable_destroy(&ls->ls_rsbtbl);
+ out_lsfree:
+	kobject_put(&ls->ls_kobj);
+	kfree(ls);
+ out:
+	module_put(THIS_MODULE);
+	return error;
+}
+
+static int __dlm_new_lockspace(const char *name, const char *cluster,
+			       uint32_t flags, int lvblen,
+			       const struct dlm_lockspace_ops *ops,
+			       void *ops_arg, int *ops_result,
+			       dlm_lockspace_t **lockspace)
+{
+	int error = 0;
+
+	mutex_lock(&ls_lock);
+	if (!ls_count)
+		error = threads_start();
+	if (error)
+		goto out;
+
+	error = new_lockspace(name, cluster, flags, lvblen, ops, ops_arg,
+			      ops_result, lockspace);
+	if (!error)
+		ls_count++;
+	if (error > 0)
+		error = 0;
+	if (!ls_count) {
+		dlm_midcomms_shutdown();
+		dlm_midcomms_stop();
+	}
+ out:
+	mutex_unlock(&ls_lock);
+	return error;
+}
+
+int dlm_new_lockspace(const char *name, const char *cluster, uint32_t flags,
+		      int lvblen, const struct dlm_lockspace_ops *ops,
+		      void *ops_arg, int *ops_result,
+		      dlm_lockspace_t **lockspace)
+{
+	return __dlm_new_lockspace(name, cluster, flags | DLM_LSFL_FS, lvblen,
+				   ops, ops_arg, ops_result, lockspace);
+}
+
+int dlm_new_user_lockspace(const char *name, const char *cluster,
+			   uint32_t flags, int lvblen,
+			   const struct dlm_lockspace_ops *ops,
+			   void *ops_arg, int *ops_result,
+			   dlm_lockspace_t **lockspace)
+{
+	if (flags & DLM_LSFL_SOFTIRQ)
+		return -EINVAL;
+
+	return __dlm_new_lockspace(name, cluster, flags, lvblen, ops,
+				   ops_arg, ops_result, lockspace);
+}
+
+/* NOTE: We check the lkbxa here rather than the resource table.
+   This is because there may be LKBs queued as ASTs that have been unlinked
+   from their RSBs and are pending deletion once the AST has been delivered */
+
+static int lockspace_busy(struct dlm_ls *ls, unsigned int release_option)
+{
+	struct dlm_lkb *lkb;
+	unsigned long id;
+	int rv = 0;
+
+	read_lock_bh(&ls->ls_lkbxa_lock);
+	if (release_option == DLM_RELEASE_NO_LOCKS) {
+		xa_for_each(&ls->ls_lkbxa, id, lkb) {
+			rv = 1;
+			break;
+		}
+	} else if (release_option == DLM_RELEASE_UNUSED) {
+		/* TODO: handle this UNUSED option as NO_LOCKS in later patch */
+		xa_for_each(&ls->ls_lkbxa, id, lkb) {
+			if (lkb->lkb_nodeid == 0 &&
+			    lkb->lkb_grmode != DLM_LOCK_IV) {
+				rv = 1;
+				break;
+			}
+		}
+	} else {
+		rv = 0;
+	}
+	read_unlock_bh(&ls->ls_lkbxa_lock);
+	return rv;
+}
+
+static int release_lockspace(struct dlm_ls *ls, unsigned int release_option)
+{
+	int busy, rv;
+
+	busy = lockspace_busy(ls, release_option);
+
+	spin_lock_bh(&lslist_lock);
+	if (ls->ls_create_count == 1) {
+		if (busy) {
+			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_bh(&lslist_lock);
+
+	if (rv) {
+		log_debug(ls, "release_lockspace no remove %d", rv);
+		return rv;
+	}
+
+	if (ls_count == 1)
+		dlm_midcomms_version_wait();
+
+	dlm_device_deregister(ls);
+
+	if (release_option != DLM_RELEASE_NO_EVENT &&
+	    dlm_user_daemon_available())
+		do_uevent(ls, 0, (release_option == DLM_RELEASE_RECOVER));
+
+	dlm_recoverd_stop(ls);
+
+	/* clear the LSFL_RUNNING flag to fast up
+	 * time_shutdown_sync(), we don't care anymore
+	 */
+	clear_bit(LSFL_RUNNING, &ls->ls_flags);
+	timer_shutdown_sync(&ls->ls_scan_timer);
+
+	if (ls_count == 1) {
+		dlm_clear_members(ls);
+		dlm_midcomms_shutdown();
+	}
+
+	dlm_callback_stop(ls);
+
+	remove_lockspace(ls);
+
+	dlm_delete_debug_file(ls);
+
+	kobject_put(&ls->ls_kobj);
+
+	xa_destroy(&ls->ls_recover_xa);
+	kfree(ls->ls_recover_buf);
+
+	/*
+	 * Free structures on any other lists
+	 */
+
+	dlm_purge_requestqueue(ls);
+	kfree(ls->ls_recover_args);
+	dlm_clear_members(ls);
+	dlm_clear_members_gone(ls);
+	kfree(ls->ls_node_array);
+
+	log_rinfo(ls, "%s final free", __func__);
+
+	/* delayed free of data structures see free_lockspace() */
+	queue_work(dlm_wq, &ls->ls_free_work);
+	module_put(THIS_MODULE);
+	return 0;
+}
+
+/*
+ * Called when a system has released all its locks and is not going to use the
+ * lockspace any longer.  We free everything we're managing for this lockspace.
+ * Remaining nodes will go through the recovery process as if we'd died.  The
+ * lockspace must continue to function as usual, participating in recoveries,
+ * until this returns.
+ *
+ * See DLM_RELEASE defines for release_option values and their meaning.
+ */
+
+int dlm_release_lockspace(void *lockspace, unsigned int release_option)
+{
+	struct dlm_ls *ls;
+	int error;
+
+	if (release_option > __DLM_RELEASE_MAX)
+		return -EINVAL;
+
+	ls = dlm_find_lockspace_local(lockspace);
+	if (!ls)
+		return -EINVAL;
+	dlm_put_lockspace(ls);
+
+	mutex_lock(&ls_lock);
+	error = release_lockspace(ls, release_option);
+	if (!error)
+		ls_count--;
+	if (!ls_count)
+		dlm_midcomms_stop();
+	mutex_unlock(&ls_lock);
+
+	return error;
+}
+
+void dlm_stop_lockspaces(void)
+{
+	struct dlm_ls *ls;
+	int count;
+
+ restart:
+	count = 0;
+	spin_lock_bh(&lslist_lock);
+	list_for_each_entry(ls, &lslist, ls_list) {
+		if (!test_bit(LSFL_RUNNING, &ls->ls_flags)) {
+			count++;
+			continue;
+		}
+		spin_unlock_bh(&lslist_lock);
+		log_error(ls, "no userland control daemon, stopping lockspace");
+		dlm_ls_stop(ls);
+		goto restart;
+	}
+	spin_unlock_bh(&lslist_lock);
+
+	if (count)
+		log_print("dlm user daemon left %d lockspaces", count);
+}