Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 809 insertions, 0 deletions

diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c
new file mode 100644
index 000000000..eedf07ca2
--- /dev/null
+++ b/fs/ocfs2/dlm/dlmthread.c
@@ -0,0 +1,809 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * dlmthread.c
+ *
+ * standalone DLM module
+ *
+ * Copyright (C) 2004 Oracle.  All rights reserved.
+ */
+
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/highmem.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/timer.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+
+
+#include "../cluster/heartbeat.h"
+#include "../cluster/nodemanager.h"
+#include "../cluster/tcp.h"
+
+#include "dlmapi.h"
+#include "dlmcommon.h"
+#include "dlmdomain.h"
+
+#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_THREAD)
+#include "../cluster/masklog.h"
+
+static int dlm_thread(void *data);
+static void dlm_flush_asts(struct dlm_ctxt *dlm);
+
+/* will exit holding res->spinlock, but may drop in function */
+/* waits until flags are cleared on res->state */
+void __dlm_wait_on_lockres_flags(struct dlm_lock_resource *res, int flags)
+{
+	DECLARE_WAITQUEUE(wait, current);
+
+	assert_spin_locked(&res->spinlock);
+
+	add_wait_queue(&res->wq, &wait);
+repeat:
+	set_current_state(TASK_UNINTERRUPTIBLE);
+	if (res->state & flags) {
+		spin_unlock(&res->spinlock);
+		schedule();
+		spin_lock(&res->spinlock);
+		goto repeat;
+	}
+	remove_wait_queue(&res->wq, &wait);
+	__set_current_state(TASK_RUNNING);
+}
+
+int __dlm_lockres_has_locks(struct dlm_lock_resource *res)
+{
+	if (list_empty(&res->granted) &&
+	    list_empty(&res->converting) &&
+	    list_empty(&res->blocked))
+		return 0;
+	return 1;
+}
+
+/* "unused": the lockres has no locks, is not on the dirty list,
+ * has no inflight locks (in the gap between mastery and acquiring
+ * the first lock), and has no bits in its refmap.
+ * truly ready to be freed. */
+int __dlm_lockres_unused(struct dlm_lock_resource *res)
+{
+	int bit;
+
+	assert_spin_locked(&res->spinlock);
+
+	if (__dlm_lockres_has_locks(res))
+		return 0;
+
+	/* Locks are in the process of being created */
+	if (res->inflight_locks)
+		return 0;
+
+	if (!list_empty(&res->dirty) || res->state & DLM_LOCK_RES_DIRTY)
+		return 0;
+
+	if (res->state & (DLM_LOCK_RES_RECOVERING|
+			DLM_LOCK_RES_RECOVERY_WAITING))
+		return 0;
+
+	/* Another node has this resource with this node as the master */
+	bit = find_first_bit(res->refmap, O2NM_MAX_NODES);
+	if (bit < O2NM_MAX_NODES)
+		return 0;
+
+	return 1;
+}
+
+
+/* Call whenever you may have added or deleted something from one of
+ * the lockres queue's. This will figure out whether it belongs on the
+ * unused list or not and does the appropriate thing. */
+void __dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
+			      struct dlm_lock_resource *res)
+{
+	assert_spin_locked(&dlm->spinlock);
+	assert_spin_locked(&res->spinlock);
+
+	if (__dlm_lockres_unused(res)){
+		if (list_empty(&res->purge)) {
+			mlog(0, "%s: Adding res %.*s to purge list\n",
+			     dlm->name, res->lockname.len, res->lockname.name);
+
+			res->last_used = jiffies;
+			dlm_lockres_get(res);
+			list_add_tail(&res->purge, &dlm->purge_list);
+			dlm->purge_count++;
+		}
+	} else if (!list_empty(&res->purge)) {
+		mlog(0, "%s: Removing res %.*s from purge list\n",
+		     dlm->name, res->lockname.len, res->lockname.name);
+
+		list_del_init(&res->purge);
+		dlm_lockres_put(res);
+		dlm->purge_count--;
+	}
+}
+
+void dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
+			    struct dlm_lock_resource *res)
+{
+	spin_lock(&dlm->spinlock);
+	spin_lock(&res->spinlock);
+
+	__dlm_lockres_calc_usage(dlm, res);
+
+	spin_unlock(&res->spinlock);
+	spin_unlock(&dlm->spinlock);
+}
+
+/*
+ * Do the real purge work:
+ *     unhash the lockres, and
+ *     clear flag DLM_LOCK_RES_DROPPING_REF.
+ * It requires dlm and lockres spinlock to be taken.
+ */
+void __dlm_do_purge_lockres(struct dlm_ctxt *dlm,
+		struct dlm_lock_resource *res)
+{
+	assert_spin_locked(&dlm->spinlock);
+	assert_spin_locked(&res->spinlock);
+
+	if (!list_empty(&res->purge)) {
+		mlog(0, "%s: Removing res %.*s from purgelist\n",
+		     dlm->name, res->lockname.len, res->lockname.name);
+		list_del_init(&res->purge);
+		dlm_lockres_put(res);
+		dlm->purge_count--;
+	}
+
+	if (!__dlm_lockres_unused(res)) {
+		mlog(ML_ERROR, "%s: res %.*s in use after deref\n",
+		     dlm->name, res->lockname.len, res->lockname.name);
+		__dlm_print_one_lock_resource(res);
+		BUG();
+	}
+
+	__dlm_unhash_lockres(dlm, res);
+
+	spin_lock(&dlm->track_lock);
+	if (!list_empty(&res->tracking))
+		list_del_init(&res->tracking);
+	else {
+		mlog(ML_ERROR, "%s: Resource %.*s not on the Tracking list\n",
+		     dlm->name, res->lockname.len, res->lockname.name);
+		__dlm_print_one_lock_resource(res);
+	}
+	spin_unlock(&dlm->track_lock);
+
+	/*
+	 * lockres is not in the hash now. drop the flag and wake up
+	 * any processes waiting in dlm_get_lock_resource.
+	 */
+	res->state &= ~DLM_LOCK_RES_DROPPING_REF;
+}
+
+static void dlm_purge_lockres(struct dlm_ctxt *dlm,
+			     struct dlm_lock_resource *res)
+{
+	int master;
+	int ret = 0;
+
+	assert_spin_locked(&dlm->spinlock);
+	assert_spin_locked(&res->spinlock);
+
+	master = (res->owner == dlm->node_num);
+
+	mlog(0, "%s: Purging res %.*s, master %d\n", dlm->name,
+	     res->lockname.len, res->lockname.name, master);
+
+	if (!master) {
+		if (res->state & DLM_LOCK_RES_DROPPING_REF) {
+			mlog(ML_NOTICE, "%s: res %.*s already in DLM_LOCK_RES_DROPPING_REF state\n",
+				dlm->name, res->lockname.len, res->lockname.name);
+			spin_unlock(&res->spinlock);
+			return;
+		}
+
+		res->state |= DLM_LOCK_RES_DROPPING_REF;
+		/* drop spinlock...  retake below */
+		spin_unlock(&res->spinlock);
+		spin_unlock(&dlm->spinlock);
+
+		spin_lock(&res->spinlock);
+		/* This ensures that clear refmap is sent after the set */
+		__dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
+		spin_unlock(&res->spinlock);
+
+		/* clear our bit from the master's refmap, ignore errors */
+		ret = dlm_drop_lockres_ref(dlm, res);
+		if (ret < 0) {
+			if (!dlm_is_host_down(ret))
+				BUG();
+		}
+		spin_lock(&dlm->spinlock);
+		spin_lock(&res->spinlock);
+	}
+
+	if (!list_empty(&res->purge)) {
+		mlog(0, "%s: Removing res %.*s from purgelist, master %d\n",
+		     dlm->name, res->lockname.len, res->lockname.name, master);
+		list_del_init(&res->purge);
+		dlm_lockres_put(res);
+		dlm->purge_count--;
+	}
+
+	if (!master && ret == DLM_DEREF_RESPONSE_INPROG) {
+		mlog(0, "%s: deref %.*s in progress\n",
+			dlm->name, res->lockname.len, res->lockname.name);
+		spin_unlock(&res->spinlock);
+		return;
+	}
+
+	if (!__dlm_lockres_unused(res)) {
+		mlog(ML_ERROR, "%s: res %.*s in use after deref\n",
+		     dlm->name, res->lockname.len, res->lockname.name);
+		__dlm_print_one_lock_resource(res);
+		BUG();
+	}
+
+	__dlm_unhash_lockres(dlm, res);
+
+	spin_lock(&dlm->track_lock);
+	if (!list_empty(&res->tracking))
+		list_del_init(&res->tracking);
+	else {
+		mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n",
+				res->lockname.len, res->lockname.name);
+		__dlm_print_one_lock_resource(res);
+	}
+	spin_unlock(&dlm->track_lock);
+
+	/* lockres is not in the hash now.  drop the flag and wake up
+	 * any processes waiting in dlm_get_lock_resource. */
+	if (!master) {
+		res->state &= ~DLM_LOCK_RES_DROPPING_REF;
+		spin_unlock(&res->spinlock);
+		wake_up(&res->wq);
+	} else
+		spin_unlock(&res->spinlock);
+}
+
+static void dlm_run_purge_list(struct dlm_ctxt *dlm,
+			       int purge_now)
+{
+	unsigned int run_max, unused;
+	unsigned long purge_jiffies;
+	struct dlm_lock_resource *lockres;
+
+	spin_lock(&dlm->spinlock);
+	run_max = dlm->purge_count;
+
+	while(run_max && !list_empty(&dlm->purge_list)) {
+		run_max--;
+
+		lockres = list_entry(dlm->purge_list.next,
+				     struct dlm_lock_resource, purge);
+
+		spin_lock(&lockres->spinlock);
+
+		purge_jiffies = lockres->last_used +
+			msecs_to_jiffies(DLM_PURGE_INTERVAL_MS);
+
+		/* Make sure that we want to be processing this guy at
+		 * this time. */
+		if (!purge_now && time_after(purge_jiffies, jiffies)) {
+			/* Since resources are added to the purge list
+			 * in tail order, we can stop at the first
+			 * unpurgable resource -- anyone added after
+			 * him will have a greater last_used value */
+			spin_unlock(&lockres->spinlock);
+			break;
+		}
+
+		/* Status of the lockres *might* change so double
+		 * check. If the lockres is unused, holding the dlm
+		 * spinlock will prevent people from getting and more
+		 * refs on it. */
+		unused = __dlm_lockres_unused(lockres);
+		if (!unused ||
+		    (lockres->state & DLM_LOCK_RES_MIGRATING) ||
+		    (lockres->inflight_assert_workers != 0)) {
+			mlog(0, "%s: res %.*s is in use or being remastered, "
+			     "used %d, state %d, assert master workers %u\n",
+			     dlm->name, lockres->lockname.len,
+			     lockres->lockname.name,
+			     !unused, lockres->state,
+			     lockres->inflight_assert_workers);
+			list_move_tail(&lockres->purge, &dlm->purge_list);
+			spin_unlock(&lockres->spinlock);
+			continue;
+		}
+
+		dlm_lockres_get(lockres);
+
+		dlm_purge_lockres(dlm, lockres);
+
+		dlm_lockres_put(lockres);
+
+		/* Avoid adding any scheduling latencies */
+		cond_resched_lock(&dlm->spinlock);
+	}
+
+	spin_unlock(&dlm->spinlock);
+}
+
+static void dlm_shuffle_lists(struct dlm_ctxt *dlm,
+			      struct dlm_lock_resource *res)
+{
+	struct dlm_lock *lock, *target;
+	int can_grant = 1;
+
+	/*
+	 * Because this function is called with the lockres
+	 * spinlock, and because we know that it is not migrating/
+	 * recovering/in-progress, it is fine to reserve asts and
+	 * basts right before queueing them all throughout
+	 */
+	assert_spin_locked(&dlm->ast_lock);
+	assert_spin_locked(&res->spinlock);
+	BUG_ON((res->state & (DLM_LOCK_RES_MIGRATING|
+			      DLM_LOCK_RES_RECOVERING|
+			      DLM_LOCK_RES_IN_PROGRESS)));
+
+converting:
+	if (list_empty(&res->converting))
+		goto blocked;
+	mlog(0, "%s: res %.*s has locks on the convert queue\n", dlm->name,
+	     res->lockname.len, res->lockname.name);
+
+	target = list_entry(res->converting.next, struct dlm_lock, list);
+	if (target->ml.convert_type == LKM_IVMODE) {
+		mlog(ML_ERROR, "%s: res %.*s converting lock to invalid mode\n",
+		     dlm->name, res->lockname.len, res->lockname.name);
+		BUG();
+	}
+	list_for_each_entry(lock, &res->granted, list) {
+		if (lock==target)
+			continue;
+		if (!dlm_lock_compatible(lock->ml.type,
+					 target->ml.convert_type)) {
+			can_grant = 0;
+			/* queue the BAST if not already */
+			if (lock->ml.highest_blocked == LKM_IVMODE) {
+				__dlm_lockres_reserve_ast(res);
+				__dlm_queue_bast(dlm, lock);
+			}
+			/* update the highest_blocked if needed */
+			if (lock->ml.highest_blocked < target->ml.convert_type)
+				lock->ml.highest_blocked =
+					target->ml.convert_type;
+		}
+	}
+
+	list_for_each_entry(lock, &res->converting, list) {
+		if (lock==target)
+			continue;
+		if (!dlm_lock_compatible(lock->ml.type,
+					 target->ml.convert_type)) {
+			can_grant = 0;
+			if (lock->ml.highest_blocked == LKM_IVMODE) {
+				__dlm_lockres_reserve_ast(res);
+				__dlm_queue_bast(dlm, lock);
+			}
+			if (lock->ml.highest_blocked < target->ml.convert_type)
+				lock->ml.highest_blocked =
+					target->ml.convert_type;
+		}
+	}
+
+	/* we can convert the lock */
+	if (can_grant) {
+		spin_lock(&target->spinlock);
+		BUG_ON(target->ml.highest_blocked != LKM_IVMODE);
+
+		mlog(0, "%s: res %.*s, AST for Converting lock %u:%llu, type "
+		     "%d => %d, node %u\n", dlm->name, res->lockname.len,
+		     res->lockname.name,
+		     dlm_get_lock_cookie_node(be64_to_cpu(target->ml.cookie)),
+		     dlm_get_lock_cookie_seq(be64_to_cpu(target->ml.cookie)),
+		     target->ml.type,
+		     target->ml.convert_type, target->ml.node);
+
+		target->ml.type = target->ml.convert_type;
+		target->ml.convert_type = LKM_IVMODE;
+		list_move_tail(&target->list, &res->granted);
+
+		BUG_ON(!target->lksb);
+		target->lksb->status = DLM_NORMAL;
+
+		spin_unlock(&target->spinlock);
+
+		__dlm_lockres_reserve_ast(res);
+		__dlm_queue_ast(dlm, target);
+		/* go back and check for more */
+		goto converting;
+	}
+
+blocked:
+	if (list_empty(&res->blocked))
+		goto leave;
+	target = list_entry(res->blocked.next, struct dlm_lock, list);
+
+	list_for_each_entry(lock, &res->granted, list) {
+		if (lock==target)
+			continue;
+		if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
+			can_grant = 0;
+			if (lock->ml.highest_blocked == LKM_IVMODE) {
+				__dlm_lockres_reserve_ast(res);
+				__dlm_queue_bast(dlm, lock);
+			}
+			if (lock->ml.highest_blocked < target->ml.type)
+				lock->ml.highest_blocked = target->ml.type;
+		}
+	}
+
+	list_for_each_entry(lock, &res->converting, list) {
+		if (lock==target)
+			continue;
+		if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
+			can_grant = 0;
+			if (lock->ml.highest_blocked == LKM_IVMODE) {
+				__dlm_lockres_reserve_ast(res);
+				__dlm_queue_bast(dlm, lock);
+			}
+			if (lock->ml.highest_blocked < target->ml.type)
+				lock->ml.highest_blocked = target->ml.type;
+		}
+	}
+
+	/* we can grant the blocked lock (only
+	 * possible if converting list empty) */
+	if (can_grant) {
+		spin_lock(&target->spinlock);
+		BUG_ON(target->ml.highest_blocked != LKM_IVMODE);
+
+		mlog(0, "%s: res %.*s, AST for Blocked lock %u:%llu, type %d, "
+		     "node %u\n", dlm->name, res->lockname.len,
+		     res->lockname.name,
+		     dlm_get_lock_cookie_node(be64_to_cpu(target->ml.cookie)),
+		     dlm_get_lock_cookie_seq(be64_to_cpu(target->ml.cookie)),
+		     target->ml.type, target->ml.node);
+
+		/* target->ml.type is already correct */
+		list_move_tail(&target->list, &res->granted);
+
+		BUG_ON(!target->lksb);
+		target->lksb->status = DLM_NORMAL;
+
+		spin_unlock(&target->spinlock);
+
+		__dlm_lockres_reserve_ast(res);
+		__dlm_queue_ast(dlm, target);
+		/* go back and check for more */
+		goto converting;
+	}
+
+leave:
+	return;
+}
+
+/* must have NO locks when calling this with res !=NULL * */
+void dlm_kick_thread(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
+{
+	if (res) {
+		spin_lock(&dlm->spinlock);
+		spin_lock(&res->spinlock);
+		__dlm_dirty_lockres(dlm, res);
+		spin_unlock(&res->spinlock);
+		spin_unlock(&dlm->spinlock);
+	}
+	wake_up(&dlm->dlm_thread_wq);
+}
+
+void __dlm_dirty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
+{
+	assert_spin_locked(&dlm->spinlock);
+	assert_spin_locked(&res->spinlock);
+
+	/* don't shuffle secondary queues */
+	if (res->owner == dlm->node_num) {
+		if (res->state & (DLM_LOCK_RES_MIGRATING |
+				  DLM_LOCK_RES_BLOCK_DIRTY))
+		    return;
+
+		if (list_empty(&res->dirty)) {
+			/* ref for dirty_list */
+			dlm_lockres_get(res);
+			list_add_tail(&res->dirty, &dlm->dirty_list);
+			res->state |= DLM_LOCK_RES_DIRTY;
+		}
+	}
+
+	mlog(0, "%s: res %.*s\n", dlm->name, res->lockname.len,
+	     res->lockname.name);
+}
+
+
+/* Launch the NM thread for the mounted volume */
+int dlm_launch_thread(struct dlm_ctxt *dlm)
+{
+	mlog(0, "Starting dlm_thread...\n");
+
+	dlm->dlm_thread_task = kthread_run(dlm_thread, dlm, "dlm-%s",
+			dlm->name);
+	if (IS_ERR(dlm->dlm_thread_task)) {
+		mlog_errno(PTR_ERR(dlm->dlm_thread_task));
+		dlm->dlm_thread_task = NULL;
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+void dlm_complete_thread(struct dlm_ctxt *dlm)
+{
+	if (dlm->dlm_thread_task) {
+		mlog(ML_KTHREAD, "Waiting for dlm thread to exit\n");
+		kthread_stop(dlm->dlm_thread_task);
+		dlm->dlm_thread_task = NULL;
+	}
+}
+
+static int dlm_dirty_list_empty(struct dlm_ctxt *dlm)
+{
+	int empty;
+
+	spin_lock(&dlm->spinlock);
+	empty = list_empty(&dlm->dirty_list);
+	spin_unlock(&dlm->spinlock);
+
+	return empty;
+}
+
+static void dlm_flush_asts(struct dlm_ctxt *dlm)
+{
+	int ret;
+	struct dlm_lock *lock;
+	struct dlm_lock_resource *res;
+	u8 hi;
+
+	spin_lock(&dlm->ast_lock);
+	while (!list_empty(&dlm->pending_asts)) {
+		lock = list_entry(dlm->pending_asts.next,
+				  struct dlm_lock, ast_list);
+		/* get an extra ref on lock */
+		dlm_lock_get(lock);
+		res = lock->lockres;
+		mlog(0, "%s: res %.*s, Flush AST for lock %u:%llu, type %d, "
+		     "node %u\n", dlm->name, res->lockname.len,
+		     res->lockname.name,
+		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
+		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
+		     lock->ml.type, lock->ml.node);
+
+		BUG_ON(!lock->ast_pending);
+
+		/* remove from list (including ref) */
+		list_del_init(&lock->ast_list);
+		dlm_lock_put(lock);
+		spin_unlock(&dlm->ast_lock);
+
+		if (lock->ml.node != dlm->node_num) {
+			ret = dlm_do_remote_ast(dlm, res, lock);
+			if (ret < 0)
+				mlog_errno(ret);
+		} else
+			dlm_do_local_ast(dlm, res, lock);
+
+		spin_lock(&dlm->ast_lock);
+
+		/* possible that another ast was queued while
+		 * we were delivering the last one */
+		if (!list_empty(&lock->ast_list)) {
+			mlog(0, "%s: res %.*s, AST queued while flushing last "
+			     "one\n", dlm->name, res->lockname.len,
+			     res->lockname.name);
+		} else
+			lock->ast_pending = 0;
+
+		/* drop the extra ref.
+		 * this may drop it completely. */
+		dlm_lock_put(lock);
+		dlm_lockres_release_ast(dlm, res);
+	}
+
+	while (!list_empty(&dlm->pending_basts)) {
+		lock = list_entry(dlm->pending_basts.next,
+				  struct dlm_lock, bast_list);
+		/* get an extra ref on lock */
+		dlm_lock_get(lock);
+		res = lock->lockres;
+
+		BUG_ON(!lock->bast_pending);
+
+		/* get the highest blocked lock, and reset */
+		spin_lock(&lock->spinlock);
+		BUG_ON(lock->ml.highest_blocked <= LKM_IVMODE);
+		hi = lock->ml.highest_blocked;
+		lock->ml.highest_blocked = LKM_IVMODE;
+		spin_unlock(&lock->spinlock);
+
+		/* remove from list (including ref) */
+		list_del_init(&lock->bast_list);
+		dlm_lock_put(lock);
+		spin_unlock(&dlm->ast_lock);
+
+		mlog(0, "%s: res %.*s, Flush BAST for lock %u:%llu, "
+		     "blocked %d, node %u\n",
+		     dlm->name, res->lockname.len, res->lockname.name,
+		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
+		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
+		     hi, lock->ml.node);
+
+		if (lock->ml.node != dlm->node_num) {
+			ret = dlm_send_proxy_bast(dlm, res, lock, hi);
+			if (ret < 0)
+				mlog_errno(ret);
+		} else
+			dlm_do_local_bast(dlm, res, lock, hi);
+
+		spin_lock(&dlm->ast_lock);
+
+		/* possible that another bast was queued while
+		 * we were delivering the last one */
+		if (!list_empty(&lock->bast_list)) {
+			mlog(0, "%s: res %.*s, BAST queued while flushing last "
+			     "one\n", dlm->name, res->lockname.len,
+			     res->lockname.name);
+		} else
+			lock->bast_pending = 0;
+
+		/* drop the extra ref.
+		 * this may drop it completely. */
+		dlm_lock_put(lock);
+		dlm_lockres_release_ast(dlm, res);
+	}
+	wake_up(&dlm->ast_wq);
+	spin_unlock(&dlm->ast_lock);
+}
+
+
+#define DLM_THREAD_TIMEOUT_MS (4 * 1000)
+#define DLM_THREAD_MAX_DIRTY  100
+
+static int dlm_thread(void *data)
+{
+	struct dlm_lock_resource *res;
+	struct dlm_ctxt *dlm = data;
+	unsigned long timeout = msecs_to_jiffies(DLM_THREAD_TIMEOUT_MS);
+
+	mlog(0, "dlm thread running for %s...\n", dlm->name);
+
+	while (!kthread_should_stop()) {
+		int n = DLM_THREAD_MAX_DIRTY;
+
+		/* dlm_shutting_down is very point-in-time, but that
+		 * doesn't matter as we'll just loop back around if we
+		 * get false on the leading edge of a state
+		 * transition. */
+		dlm_run_purge_list(dlm, dlm_shutting_down(dlm));
+
+		/* We really don't want to hold dlm->spinlock while
+		 * calling dlm_shuffle_lists on each lockres that
+		 * needs to have its queues adjusted and AST/BASTs
+		 * run.  So let's pull each entry off the dirty_list
+		 * and drop dlm->spinlock ASAP.  Once off the list,
+		 * res->spinlock needs to be taken again to protect
+		 * the queues while calling dlm_shuffle_lists.  */
+		spin_lock(&dlm->spinlock);
+		while (!list_empty(&dlm->dirty_list)) {
+			int delay = 0;
+			res = list_entry(dlm->dirty_list.next,
+					 struct dlm_lock_resource, dirty);
+
+			/* peel a lockres off, remove it from the list,
+			 * unset the dirty flag and drop the dlm lock */
+			BUG_ON(!res);
+			dlm_lockres_get(res);
+
+			spin_lock(&res->spinlock);
+			/* We clear the DLM_LOCK_RES_DIRTY state once we shuffle lists below */
+			list_del_init(&res->dirty);
+			spin_unlock(&res->spinlock);
+			spin_unlock(&dlm->spinlock);
+			/* Drop dirty_list ref */
+			dlm_lockres_put(res);
+
+		 	/* lockres can be re-dirtied/re-added to the
+			 * dirty_list in this gap, but that is ok */
+
+			spin_lock(&dlm->ast_lock);
+			spin_lock(&res->spinlock);
+			if (res->owner != dlm->node_num) {
+				__dlm_print_one_lock_resource(res);
+				mlog(ML_ERROR, "%s: inprog %d, mig %d, reco %d,"
+				     " dirty %d\n", dlm->name,
+				     !!(res->state & DLM_LOCK_RES_IN_PROGRESS),
+				     !!(res->state & DLM_LOCK_RES_MIGRATING),
+				     !!(res->state & DLM_LOCK_RES_RECOVERING),
+				     !!(res->state & DLM_LOCK_RES_DIRTY));
+			}
+			BUG_ON(res->owner != dlm->node_num);
+
+			/* it is now ok to move lockreses in these states
+			 * to the dirty list, assuming that they will only be
+			 * dirty for a short while. */
+			BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
+			if (res->state & (DLM_LOCK_RES_IN_PROGRESS |
+					  DLM_LOCK_RES_RECOVERING |
+					  DLM_LOCK_RES_RECOVERY_WAITING)) {
+				/* move it to the tail and keep going */
+				res->state &= ~DLM_LOCK_RES_DIRTY;
+				spin_unlock(&res->spinlock);
+				spin_unlock(&dlm->ast_lock);
+				mlog(0, "%s: res %.*s, inprogress, delay list "
+				     "shuffle, state %d\n", dlm->name,
+				     res->lockname.len, res->lockname.name,
+				     res->state);
+				delay = 1;
+				goto in_progress;
+			}
+
+			/* at this point the lockres is not migrating/
+			 * recovering/in-progress.  we have the lockres
+			 * spinlock and do NOT have the dlm lock.
+			 * safe to reserve/queue asts and run the lists. */
+
+			/* called while holding lockres lock */
+			dlm_shuffle_lists(dlm, res);
+			res->state &= ~DLM_LOCK_RES_DIRTY;
+			spin_unlock(&res->spinlock);
+			spin_unlock(&dlm->ast_lock);
+
+			dlm_lockres_calc_usage(dlm, res);
+
+in_progress:
+
+			spin_lock(&dlm->spinlock);
+			/* if the lock was in-progress, stick
+			 * it on the back of the list */
+			if (delay) {
+				spin_lock(&res->spinlock);
+				__dlm_dirty_lockres(dlm, res);
+				spin_unlock(&res->spinlock);
+			}
+			dlm_lockres_put(res);
+
+			/* unlikely, but we may need to give time to
+			 * other tasks */
+			if (!--n) {
+				mlog(0, "%s: Throttling dlm thread\n",
+				     dlm->name);
+				break;
+			}
+		}
+
+		spin_unlock(&dlm->spinlock);
+		dlm_flush_asts(dlm);
+
+		/* yield and continue right away if there is more work to do */
+		if (!n) {
+			cond_resched();
+			continue;
+		}
+
+		wait_event_interruptible_timeout(dlm->dlm_thread_wq,
+						 !dlm_dirty_list_empty(dlm) ||
+						 kthread_should_stop(),
+						 timeout);
+	}
+
+	mlog(0, "quitting DLM thread\n");
+	return 0;
+}