/******************************************************************************
  *******************************************************************************
  **

  **  Copyright (C) 2005-2009 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
  **  of the GNU General Public License v.2.
  **
  *******************************************************************************
  ******************************************************************************/
  
  #include <linux/pagemap.h>
  #include <linux/seq_file.h>
  #include <linux/module.h>
  #include <linux/ctype.h>
  #include <linux/debugfs.h>

  #include <linux/slab.h>

  
  #include "dlm_internal.h"

  #include "lock.h"

  #define DLM_DEBUG_BUF_LEN 4096
  static char debug_buf[DLM_DEBUG_BUF_LEN];
  static struct mutex debug_buf_lock;

  
  static struct dentry *dlm_root;

  static char *print_lockmode(int mode)
  {
  	switch (mode) {
  	case DLM_LOCK_IV:
  		return "--";
  	case DLM_LOCK_NL:
  		return "NL";
  	case DLM_LOCK_CR:
  		return "CR";
  	case DLM_LOCK_CW:
  		return "CW";
  	case DLM_LOCK_PR:
  		return "PR";
  	case DLM_LOCK_PW:
  		return "PW";
  	case DLM_LOCK_EX:
  		return "EX";
  	default:
  		return "??";
  	}
  }

  static void print_format1_lock(struct seq_file *s, struct dlm_lkb *lkb,
  			       struct dlm_rsb *res)

  {
  	seq_printf(s, "%08x %s", lkb->lkb_id, print_lockmode(lkb->lkb_grmode));

  	if (lkb->lkb_status == DLM_LKSTS_CONVERT ||
  	    lkb->lkb_status == DLM_LKSTS_WAITING)

  		seq_printf(s, " (%s)", print_lockmode(lkb->lkb_rqmode));

  	if (lkb->lkb_nodeid) {
  		if (lkb->lkb_nodeid != res->res_nodeid)
  			seq_printf(s, " Remote: %3d %08x", lkb->lkb_nodeid,
  				   lkb->lkb_remid);
  		else
  			seq_printf(s, " Master:     %08x", lkb->lkb_remid);
  	}
  
  	if (lkb->lkb_wait_type)
  		seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);

  	seq_puts(s, "
  ");

  }

  static void print_format1(struct dlm_rsb *res, struct seq_file *s)

  {
  	struct dlm_lkb *lkb;

  	int i, lvblen = res->res_ls->ls_lvblen, recover_list, root_list;

  	lock_rsb(res);

  	seq_printf(s, "
  Resource %p Name (len=%d) \"", res, res->res_length);

  	for (i = 0; i < res->res_length; i++) {
  		if (isprint(res->res_name[i]))
  			seq_printf(s, "%c", res->res_name[i]);
  		else
  			seq_printf(s, "%c", '.');
  	}

  	if (res->res_nodeid > 0)

  		seq_printf(s, "\"
  Local Copy, Master is node %d
  ",
  			   res->res_nodeid);

  	else if (res->res_nodeid == 0)

  		seq_puts(s, "\"
  Master Copy
  ");

  	else if (res->res_nodeid == -1)

  		seq_printf(s, "\"
  Looking up master (lkid %x)
  ",
  			   res->res_first_lkid);

  	else

  		seq_printf(s, "\"
  Invalid master %d
  ", res->res_nodeid);
  	if (seq_has_overflowed(s))

  		goto out;

  
  	/* Print the LVB: */
  	if (res->res_lvbptr) {

  		seq_puts(s, "LVB: ");

  		for (i = 0; i < lvblen; i++) {
  			if (i == lvblen / 2)

  				seq_puts(s, "
       ");

  			seq_printf(s, "%02x ",
  				   (unsigned char) res->res_lvbptr[i]);
  		}
  		if (rsb_flag(res, RSB_VALNOTVALID))

  			seq_puts(s, " (INVALID)");

  		seq_puts(s, "
  ");
  		if (seq_has_overflowed(s))

  			goto out;

  	}

  	root_list = !list_empty(&res->res_root_list);
  	recover_list = !list_empty(&res->res_recover_list);
  
  	if (root_list || recover_list) {

  		seq_printf(s, "Recovery: root %d recover %d flags %lx count %d
  ",
  			   root_list, recover_list,
  			   res->res_flags, res->res_recover_locks_count);

  	}

  	/* Print the locks attached to this resource */

  	seq_puts(s, "Granted Queue
  ");

  	list_for_each_entry(lkb, &res->res_grantqueue, lkb_statequeue) {

  		print_format1_lock(s, lkb, res);
  		if (seq_has_overflowed(s))

  			goto out;
  	}

  	seq_puts(s, "Conversion Queue
  ");

  	list_for_each_entry(lkb, &res->res_convertqueue, lkb_statequeue) {

  		print_format1_lock(s, lkb, res);
  		if (seq_has_overflowed(s))

  			goto out;
  	}

  	seq_puts(s, "Waiting Queue
  ");

  	list_for_each_entry(lkb, &res->res_waitqueue, lkb_statequeue) {

  		print_format1_lock(s, lkb, res);
  		if (seq_has_overflowed(s))

  			goto out;
  	}

  	if (list_empty(&res->res_lookup))
  		goto out;

  	seq_puts(s, "Lookup Queue
  ");

  	list_for_each_entry(lkb, &res->res_lookup, lkb_rsb_lookup) {

  		seq_printf(s, "%08x %s",
  			   lkb->lkb_id, print_lockmode(lkb->lkb_rqmode));

  		if (lkb->lkb_wait_type)
  			seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);

  		seq_puts(s, "
  ");
  		if (seq_has_overflowed(s))
  			goto out;

  	}
   out:

  	unlock_rsb(res);

  }

  static void print_format2_lock(struct seq_file *s, struct dlm_lkb *lkb,
  			       struct dlm_rsb *r)

  {

  	u64 xid = 0;
  	u64 us;

  
  	if (lkb->lkb_flags & DLM_IFL_USER) {

  		if (lkb->lkb_ua)
  			xid = lkb->lkb_ua->xid;

  	}

  	/* microseconds since lkb was added to current queue */
  	us = ktime_to_us(ktime_sub(ktime_get(), lkb->lkb_timestamp));

  	/* id nodeid remid pid xid exflags flags sts grmode rqmode time_us

  	   r_nodeid r_len r_name */

  	seq_printf(s, "%x %d %x %u %llu %x %x %d %d %d %llu %u %d \"%s\"
  ",
  		   lkb->lkb_id,
  		   lkb->lkb_nodeid,
  		   lkb->lkb_remid,
  		   lkb->lkb_ownpid,
  		   (unsigned long long)xid,
  		   lkb->lkb_exflags,
  		   lkb->lkb_flags,
  		   lkb->lkb_status,
  		   lkb->lkb_grmode,
  		   lkb->lkb_rqmode,
  		   (unsigned long long)us,
  		   r->res_nodeid,
  		   r->res_length,
  		   r->res_name);

  }

  static void print_format2(struct dlm_rsb *r, struct seq_file *s)

  {
  	struct dlm_lkb *lkb;
  
  	lock_rsb(r);

  	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {

  		print_format2_lock(s, lkb, r);
  		if (seq_has_overflowed(s))

  			goto out;
  	}

  	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {

  		print_format2_lock(s, lkb, r);
  		if (seq_has_overflowed(s))

  			goto out;
  	}

  	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue) {

  		print_format2_lock(s, lkb, r);
  		if (seq_has_overflowed(s))

  			goto out;
  	}
   out:

  	unlock_rsb(r);

  }

  static void print_format3_lock(struct seq_file *s, struct dlm_lkb *lkb,

  			      int rsb_lookup)

  {
  	u64 xid = 0;
  
  	if (lkb->lkb_flags & DLM_IFL_USER) {
  		if (lkb->lkb_ua)
  			xid = lkb->lkb_ua->xid;
  	}

  	seq_printf(s, "lkb %x %d %x %u %llu %x %x %d %d %d %d %d %d %u %llu %llu
  ",
  		   lkb->lkb_id,
  		   lkb->lkb_nodeid,
  		   lkb->lkb_remid,
  		   lkb->lkb_ownpid,
  		   (unsigned long long)xid,
  		   lkb->lkb_exflags,
  		   lkb->lkb_flags,
  		   lkb->lkb_status,
  		   lkb->lkb_grmode,
  		   lkb->lkb_rqmode,
  		   lkb->lkb_last_bast.mode,
  		   rsb_lookup,
  		   lkb->lkb_wait_type,
  		   lkb->lkb_lvbseq,
  		   (unsigned long long)ktime_to_ns(lkb->lkb_timestamp),
  		   (unsigned long long)ktime_to_ns(lkb->lkb_last_bast_time));

  }

  static void print_format3(struct dlm_rsb *r, struct seq_file *s)

  {
  	struct dlm_lkb *lkb;
  	int i, lvblen = r->res_ls->ls_lvblen;
  	int print_name = 1;
  
  	lock_rsb(r);

  	seq_printf(s, "rsb %p %d %x %lx %d %d %u %d ",
  		   r,
  		   r->res_nodeid,
  		   r->res_first_lkid,
  		   r->res_flags,
  		   !list_empty(&r->res_root_list),
  		   !list_empty(&r->res_recover_list),
  		   r->res_recover_locks_count,
  		   r->res_length);
  	if (seq_has_overflowed(s))

  		goto out;

  
  	for (i = 0; i < r->res_length; i++) {
  		if (!isascii(r->res_name[i]) || !isprint(r->res_name[i]))
  			print_name = 0;
  	}

  	seq_puts(s, print_name ? "str " : "hex");

  
  	for (i = 0; i < r->res_length; i++) {
  		if (print_name)
  			seq_printf(s, "%c", r->res_name[i]);
  		else
  			seq_printf(s, " %02x", (unsigned char)r->res_name[i]);
  	}

  	seq_puts(s, "
  ");
  	if (seq_has_overflowed(s))

  		goto out;

  
  	if (!r->res_lvbptr)
  		goto do_locks;
  
  	seq_printf(s, "lvb %u %d", r->res_lvbseq, lvblen);
  
  	for (i = 0; i < lvblen; i++)
  		seq_printf(s, " %02x", (unsigned char)r->res_lvbptr[i]);

  	seq_puts(s, "
  ");
  	if (seq_has_overflowed(s))

  		goto out;

  
   do_locks:

  	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {

  		print_format3_lock(s, lkb, 0);
  		if (seq_has_overflowed(s))

  			goto out;

  	}

  	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {

  		print_format3_lock(s, lkb, 0);
  		if (seq_has_overflowed(s))

  			goto out;

  	}

  	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue) {

  		print_format3_lock(s, lkb, 0);
  		if (seq_has_overflowed(s))

  			goto out;

  	}

  	list_for_each_entry(lkb, &r->res_lookup, lkb_rsb_lookup) {

  		print_format3_lock(s, lkb, 1);
  		if (seq_has_overflowed(s))

  			goto out;

  	}

   out:
  	unlock_rsb(r);

  }

  static void print_format4(struct dlm_rsb *r, struct seq_file *s)

  {
  	int our_nodeid = dlm_our_nodeid();
  	int print_name = 1;

  	int i;

  
  	lock_rsb(r);

  	seq_printf(s, "rsb %p %d %d %d %d %lu %lx %d ",
  		   r,
  		   r->res_nodeid,
  		   r->res_master_nodeid,
  		   r->res_dir_nodeid,
  		   our_nodeid,
  		   r->res_toss_time,
  		   r->res_flags,
  		   r->res_length);

  
  	for (i = 0; i < r->res_length; i++) {
  		if (!isascii(r->res_name[i]) || !isprint(r->res_name[i]))
  			print_name = 0;
  	}

  	seq_puts(s, print_name ? "str " : "hex");

  
  	for (i = 0; i < r->res_length; i++) {
  		if (print_name)
  			seq_printf(s, "%c", r->res_name[i]);
  		else
  			seq_printf(s, " %02x", (unsigned char)r->res_name[i]);
  	}

  	seq_puts(s, "
  ");

  	unlock_rsb(r);

  }

  struct rsbtbl_iter {
  	struct dlm_rsb *rsb;
  	unsigned bucket;
  	int format;
  	int header;
  };

  /*
   * If the buffer is full, seq_printf can be called again, but it
   * does nothing.  So, the these printing routines periodically check
   * seq_has_overflowed to avoid wasting too much time trying to print to
   * a full buffer.
   */

  
  static int table_seq_show(struct seq_file *seq, void *iter_ptr)

  {

  	struct rsbtbl_iter *ri = iter_ptr;

  	switch (ri->format) {
  	case 1:

  		print_format1(ri->rsb, seq);

  		break;
  	case 2:

  		if (ri->header) {

  			seq_puts(seq, "id nodeid remid pid xid exflags flags sts grmode rqmode time_ms r_nodeid r_len r_name
  ");

  			ri->header = 0;
  		}

  		print_format2(ri->rsb, seq);

  		break;
  	case 3:
  		if (ri->header) {

  			seq_puts(seq, "version rsb 1.1 lvb 1.1 lkb 1.1
  ");

  			ri->header = 0;
  		}

  		print_format3(ri->rsb, seq);

  		break;

  	case 4:
  		if (ri->header) {

  			seq_puts(seq, "version 4 rsb 2
  ");

  			ri->header = 0;
  		}

  		print_format4(ri->rsb, seq);

  		break;

  	}

  	return 0;

  }

  static const struct seq_operations format1_seq_ops;
  static const struct seq_operations format2_seq_ops;
  static const struct seq_operations format3_seq_ops;

  static const struct seq_operations format4_seq_ops;

  static void *table_seq_start(struct seq_file *seq, loff_t *pos)

  {

  	struct rb_root *tree;

  	struct rb_node *node;

  	struct dlm_ls *ls = seq->private;
  	struct rsbtbl_iter *ri;
  	struct dlm_rsb *r;
  	loff_t n = *pos;
  	unsigned bucket, entry;

  	int toss = (seq->op == &format4_seq_ops);

  	bucket = n >> 32;
  	entry = n & ((1LL << 32) - 1);

  	if (bucket >= ls->ls_rsbtbl_size)
  		return NULL;

  	ri = kzalloc(sizeof(struct rsbtbl_iter), GFP_NOFS);

  	if (!ri)
  		return NULL;

  	if (n == 0)

  		ri->header = 1;

  	if (seq->op == &format1_seq_ops)
  		ri->format = 1;
  	if (seq->op == &format2_seq_ops)
  		ri->format = 2;
  	if (seq->op == &format3_seq_ops)
  		ri->format = 3;

  	if (seq->op == &format4_seq_ops)
  		ri->format = 4;
  
  	tree = toss ? &ls->ls_rsbtbl[bucket].toss : &ls->ls_rsbtbl[bucket].keep;

  	spin_lock(&ls->ls_rsbtbl[bucket].lock);

  	if (!RB_EMPTY_ROOT(tree)) {
  		for (node = rb_first(tree); node; node = rb_next(node)) {

  			r = rb_entry(node, struct dlm_rsb, res_hashnode);

  			if (!entry--) {
  				dlm_hold_rsb(r);
  				ri->rsb = r;
  				ri->bucket = bucket;

  				spin_unlock(&ls->ls_rsbtbl[bucket].lock);

  				return ri;
  			}
  		}

  	}

  	spin_unlock(&ls->ls_rsbtbl[bucket].lock);

  	/*
  	 * move to the first rsb in the next non-empty bucket
  	 */

  	/* zero the entry */
  	n &= ~((1LL << 32) - 1);

  	while (1) {
  		bucket++;
  		n += 1LL << 32;

  		if (bucket >= ls->ls_rsbtbl_size) {
  			kfree(ri);

  			return NULL;
  		}

  		tree = toss ? &ls->ls_rsbtbl[bucket].toss : &ls->ls_rsbtbl[bucket].keep;

  		spin_lock(&ls->ls_rsbtbl[bucket].lock);

  		if (!RB_EMPTY_ROOT(tree)) {
  			node = rb_first(tree);

  			r = rb_entry(node, struct dlm_rsb, res_hashnode);

  			dlm_hold_rsb(r);
  			ri->rsb = r;
  			ri->bucket = bucket;

  			spin_unlock(&ls->ls_rsbtbl[bucket].lock);

  			*pos = n;
  			return ri;
  		}

  		spin_unlock(&ls->ls_rsbtbl[bucket].lock);

  	}

  }

  static void *table_seq_next(struct seq_file *seq, void *iter_ptr, loff_t *pos)

  {

  	struct dlm_ls *ls = seq->private;
  	struct rsbtbl_iter *ri = iter_ptr;

  	struct rb_root *tree;

  	struct rb_node *next;

  	struct dlm_rsb *r, *rp;
  	loff_t n = *pos;
  	unsigned bucket;

  	int toss = (seq->op == &format4_seq_ops);

  
  	bucket = n >> 32;
  
  	/*
  	 * move to the next rsb in the same bucket
  	 */

  	spin_lock(&ls->ls_rsbtbl[bucket].lock);

  	rp = ri->rsb;

  	next = rb_next(&rp->res_hashnode);

  	if (next) {
  		r = rb_entry(next, struct dlm_rsb, res_hashnode);

  		dlm_hold_rsb(r);
  		ri->rsb = r;

  		spin_unlock(&ls->ls_rsbtbl[bucket].lock);

  		dlm_put_rsb(rp);
  		++*pos;
  		return ri;
  	}

  	spin_unlock(&ls->ls_rsbtbl[bucket].lock);

  	dlm_put_rsb(rp);

  	/*
  	 * move to the first rsb in the next non-empty bucket
  	 */

  	/* zero the entry */
  	n &= ~((1LL << 32) - 1);

  	while (1) {
  		bucket++;
  		n += 1LL << 32;

  		if (bucket >= ls->ls_rsbtbl_size) {
  			kfree(ri);
  			return NULL;
  		}

  		tree = toss ? &ls->ls_rsbtbl[bucket].toss : &ls->ls_rsbtbl[bucket].keep;

  		spin_lock(&ls->ls_rsbtbl[bucket].lock);

  		if (!RB_EMPTY_ROOT(tree)) {
  			next = rb_first(tree);

  			r = rb_entry(next, struct dlm_rsb, res_hashnode);

  			dlm_hold_rsb(r);
  			ri->rsb = r;
  			ri->bucket = bucket;

  			spin_unlock(&ls->ls_rsbtbl[bucket].lock);

  			*pos = n;
  			return ri;
  		}

  		spin_unlock(&ls->ls_rsbtbl[bucket].lock);

  	}

  }

  static void table_seq_stop(struct seq_file *seq, void *iter_ptr)

  {

  	struct rsbtbl_iter *ri = iter_ptr;

  	if (ri) {
  		dlm_put_rsb(ri->rsb);
  		kfree(ri);

  	}

  }

  static const struct seq_operations format1_seq_ops = {

  	.start = table_seq_start,
  	.next  = table_seq_next,
  	.stop  = table_seq_stop,
  	.show  = table_seq_show,

  };

  static const struct seq_operations format2_seq_ops = {

  	.start = table_seq_start,
  	.next  = table_seq_next,
  	.stop  = table_seq_stop,
  	.show  = table_seq_show,
  };

  static const struct seq_operations format3_seq_ops = {

  	.start = table_seq_start,
  	.next  = table_seq_next,
  	.stop  = table_seq_stop,
  	.show  = table_seq_show,
  };

  static const struct seq_operations format4_seq_ops = {
  	.start = table_seq_start,
  	.next  = table_seq_next,
  	.stop  = table_seq_stop,
  	.show  = table_seq_show,
  };

  static const struct file_operations format1_fops;
  static const struct file_operations format2_fops;
  static const struct file_operations format3_fops;

  static const struct file_operations format4_fops;

  
  static int table_open(struct inode *inode, struct file *file)

  {
  	struct seq_file *seq;

  	int ret = -1;
  
  	if (file->f_op == &format1_fops)
  		ret = seq_open(file, &format1_seq_ops);
  	else if (file->f_op == &format2_fops)
  		ret = seq_open(file, &format2_seq_ops);
  	else if (file->f_op == &format3_fops)
  		ret = seq_open(file, &format3_seq_ops);

  	else if (file->f_op == &format4_fops)
  		ret = seq_open(file, &format4_seq_ops);

  	if (ret)
  		return ret;
  
  	seq = file->private_data;

  	seq->private = inode->i_private; /* the dlm_ls */

  	return 0;
  }

  static const struct file_operations format1_fops = {
  	.owner   = THIS_MODULE,
  	.open    = table_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,
  	.release = seq_release
  };
  
  static const struct file_operations format2_fops = {
  	.owner   = THIS_MODULE,
  	.open    = table_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,
  	.release = seq_release
  };
  
  static const struct file_operations format3_fops = {

  	.owner   = THIS_MODULE,

  	.open    = table_open,

  	.read    = seq_read,
  	.llseek  = seq_lseek,
  	.release = seq_release
  };

  static const struct file_operations format4_fops = {
  	.owner   = THIS_MODULE,
  	.open    = table_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,
  	.release = seq_release
  };

  /*

   * dump lkb's on the ls_waiters list
   */

  static ssize_t waiters_read(struct file *file, char __user *userbuf,
  			    size_t count, loff_t *ppos)
  {
  	struct dlm_ls *ls = file->private_data;
  	struct dlm_lkb *lkb;

  	size_t len = DLM_DEBUG_BUF_LEN, pos = 0, ret, rv;

  
  	mutex_lock(&debug_buf_lock);
  	mutex_lock(&ls->ls_waiters_mutex);
  	memset(debug_buf, 0, sizeof(debug_buf));
  
  	list_for_each_entry(lkb, &ls->ls_waiters, lkb_wait_reply) {

  		ret = snprintf(debug_buf + pos, len - pos, "%x %d %d %s
  ",
  			       lkb->lkb_id, lkb->lkb_wait_type,
  			       lkb->lkb_nodeid, lkb->lkb_resource->res_name);
  		if (ret >= len - pos)
  			break;
  		pos += ret;

  	}
  	mutex_unlock(&ls->ls_waiters_mutex);
  
  	rv = simple_read_from_buffer(userbuf, count, ppos, debug_buf, pos);
  	mutex_unlock(&debug_buf_lock);
  	return rv;
  }

  static const struct file_operations waiters_fops = {

  	.owner   = THIS_MODULE,

  	.open    = simple_open,

  	.read    = waiters_read,
  	.llseek  = default_llseek,

  };

  void dlm_delete_debug_file(struct dlm_ls *ls)
  {

  	debugfs_remove(ls->ls_debug_rsb_dentry);
  	debugfs_remove(ls->ls_debug_waiters_dentry);
  	debugfs_remove(ls->ls_debug_locks_dentry);
  	debugfs_remove(ls->ls_debug_all_dentry);
  	debugfs_remove(ls->ls_debug_toss_dentry);

  }

  int dlm_create_debug_file(struct dlm_ls *ls)
  {

  	char name[DLM_LOCKSPACE_LEN+8];

  	/* format 1 */

  	ls->ls_debug_rsb_dentry = debugfs_create_file(ls->ls_name,
  						      S_IFREG | S_IRUGO,
  						      dlm_root,
  						      ls,

  						      &format1_fops);

  	if (!ls->ls_debug_rsb_dentry)

  		goto fail;

  	/* format 2 */

  	memset(name, 0, sizeof(name));

  	snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_locks", ls->ls_name);
  
  	ls->ls_debug_locks_dentry = debugfs_create_file(name,
  							S_IFREG | S_IRUGO,
  							dlm_root,
  							ls,

  							&format2_fops);

  	if (!ls->ls_debug_locks_dentry)
  		goto fail;
  
  	/* format 3 */
  
  	memset(name, 0, sizeof(name));
  	snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_all", ls->ls_name);
  
  	ls->ls_debug_all_dentry = debugfs_create_file(name,
  						      S_IFREG | S_IRUGO,
  						      dlm_root,
  						      ls,

  						      &format3_fops);

  	if (!ls->ls_debug_all_dentry)
  		goto fail;

  	/* format 4 */
  
  	memset(name, 0, sizeof(name));
  	snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_toss", ls->ls_name);
  
  	ls->ls_debug_toss_dentry = debugfs_create_file(name,
  						       S_IFREG | S_IRUGO,
  						       dlm_root,
  						       ls,
  						       &format4_fops);
  	if (!ls->ls_debug_toss_dentry)
  		goto fail;

  	memset(name, 0, sizeof(name));
  	snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_waiters", ls->ls_name);
  
  	ls->ls_debug_waiters_dentry = debugfs_create_file(name,
  							  S_IFREG | S_IRUGO,
  							  dlm_root,
  							  ls,
  							  &waiters_fops);
  	if (!ls->ls_debug_waiters_dentry)
  		goto fail;

  	return 0;

   fail:
  	dlm_delete_debug_file(ls);
  	return -ENOMEM;

  }

  int __init dlm_register_debugfs(void)

  {

  	mutex_init(&debug_buf_lock);

  	dlm_root = debugfs_create_dir("dlm", NULL);
  	return dlm_root ? 0 : -ENOMEM;
  }
  
  void dlm_unregister_debugfs(void)
  {
  	debugfs_remove(dlm_root);
  }