root/fs/dlm/debug_fs.c
// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
*******************************************************************************
**
**  Copyright (C) 2005-2009 Red Hat, Inc.  All rights reserved.
**
**
*******************************************************************************
******************************************************************************/

#include <linux/pagemap.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/ctype.h>
#include <linux/debugfs.h>
#include <linux/slab.h>

#include "dlm_internal.h"
#include "midcomms.h"
#include "lock.h"
#include "ast.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 struct dentry *dlm_comms;

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_putc(s, '\n');
}

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, "\nResource %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, "\"\nLocal Copy, Master is node %d\n",
                           res->res_nodeid);
        else if (res->res_nodeid == 0)
                seq_puts(s, "\"\nMaster Copy\n");
        else if (res->res_nodeid == -1)
                seq_printf(s, "\"\nLooking up master (lkid %x)\n",
                           res->res_first_lkid);
        else
                seq_printf(s, "\"\nInvalid master %d\n", 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, "\n     ");
                        seq_printf(s, "%02x ",
                                   (unsigned char) res->res_lvbptr[i]);
                }
                if (rsb_flag(res, RSB_VALNOTVALID))
                        seq_puts(s, " (INVALID)");
                seq_putc(s, '\n');
                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\n",
                           root_list, recover_list,
                           res->res_flags, res->res_recover_locks_count);
        }

        /* Print the locks attached to this resource */
        seq_puts(s, "Granted Queue\n");
        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\n");
        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\n");
        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\n");
        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_putc(s, '\n');
                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 (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
                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\"\n",
                   lkb->lkb_id,
                   lkb->lkb_nodeid,
                   lkb->lkb_remid,
                   lkb->lkb_ownpid,
                   (unsigned long long)xid,
                   lkb->lkb_exflags,
                   dlm_iflags_val(lkb),
                   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 (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
                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\n",
                   lkb->lkb_id,
                   lkb->lkb_nodeid,
                   lkb->lkb_remid,
                   lkb->lkb_ownpid,
                   (unsigned long long)xid,
                   lkb->lkb_exflags,
                   dlm_iflags_val(lkb),
                   lkb->lkb_status,
                   lkb->lkb_grmode,
                   lkb->lkb_rqmode,
                   lkb->lkb_last_bast_cb_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_putc(s, '\n');
        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_putc(s, '\n');
        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_putc(s, '\n');
        unlock_rsb(r);
}

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;

/*
 * 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 dlm_rsb *rsb = list_entry(iter_ptr, struct dlm_rsb, res_slow_list);

        if (seq->op == &format1_seq_ops)
                print_format1(rsb, seq);
        else if (seq->op == &format2_seq_ops)
                print_format2(rsb, seq);
        else if (seq->op == &format3_seq_ops)
                print_format3(rsb, seq);
        else if (seq->op == &format4_seq_ops)
                print_format4(rsb, seq);

        return 0;
}

static void *table_seq_start(struct seq_file *seq, loff_t *pos)
{
        struct dlm_ls *ls = seq->private;
        struct list_head *list;

        if (!*pos) {
                if (seq->op == &format2_seq_ops)
                        seq_puts(seq, "id nodeid remid pid xid exflags flags sts grmode rqmode time_ms r_nodeid r_len r_name\n");
                else if (seq->op == &format3_seq_ops)
                        seq_puts(seq, "rsb ptr nodeid first_lkid flags !root_list_empty !recover_list_empty recover_locks_count len\n");
                else if (seq->op == &format4_seq_ops)
                        seq_puts(seq, "rsb ptr nodeid master_nodeid dir_nodeid our_nodeid toss_time flags len str|hex name\n");
        }

        if (seq->op == &format4_seq_ops)
                list = &ls->ls_slow_inactive;
        else
                list = &ls->ls_slow_active;

        read_lock_bh(&ls->ls_rsbtbl_lock);
        return seq_list_start(list, *pos);
}

static void *table_seq_next(struct seq_file *seq, void *iter_ptr, loff_t *pos)
{
        struct dlm_ls *ls = seq->private;
        struct list_head *list;

        if (seq->op == &format4_seq_ops)
                list = &ls->ls_slow_inactive;
        else
                list = &ls->ls_slow_active;

        return seq_list_next(iter_ptr, list, pos);
}

static void table_seq_stop(struct seq_file *seq, void *iter_ptr)
{
        struct dlm_ls *ls = seq->private;

        read_unlock_bh(&ls->ls_rsbtbl_lock);
}

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_open1(struct inode *inode, struct file *file)
{
        struct seq_file *seq;
        int ret;

        ret = seq_open(file, &format1_seq_ops);
        if (ret)
                return ret;

        seq = file->private_data;
        seq->private = inode->i_private; /* the dlm_ls */
        return 0;
}

static int table_open2(struct inode *inode, struct file *file)
{
        struct seq_file *seq;
        int ret;

        ret = seq_open(file, &format2_seq_ops);
        if (ret)
                return ret;

        seq = file->private_data;
        seq->private = inode->i_private; /* the dlm_ls */
        return 0;
}

static ssize_t table_write2(struct file *file, const char __user *user_buf,
                            size_t count, loff_t *ppos)
{
        struct seq_file *seq = file->private_data;
        int n, len, lkb_nodeid, lkb_status, error;
        char name[DLM_RESNAME_MAXLEN + 1] = {};
        struct dlm_ls *ls = seq->private;
        unsigned int lkb_flags;
        char buf[256] = {};
        uint32_t lkb_id;

        if (copy_from_user(buf, user_buf,
                           min_t(size_t, sizeof(buf) - 1, count)))
                return -EFAULT;

        n = sscanf(buf, "%x %" __stringify(DLM_RESNAME_MAXLEN) "s %x %d %d",
                   &lkb_id, name, &lkb_flags, &lkb_nodeid, &lkb_status);
        if (n != 5)
                return -EINVAL;

        len = strnlen(name, DLM_RESNAME_MAXLEN);
        error = dlm_debug_add_lkb(ls, lkb_id, name, len, lkb_flags,
                                  lkb_nodeid, lkb_status);
        if (error)
                return error;

        return count;
}

static int table_open3(struct inode *inode, struct file *file)
{
        struct seq_file *seq;
        int ret;

        ret = seq_open(file, &format3_seq_ops);
        if (ret)
                return ret;

        seq = file->private_data;
        seq->private = inode->i_private; /* the dlm_ls */
        return 0;
}

static int table_open4(struct inode *inode, struct file *file)
{
        struct seq_file *seq;
        int ret;

        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_open1,
        .read    = seq_read,
        .llseek  = seq_lseek,
        .release = seq_release
};

static const struct file_operations format2_fops = {
        .owner   = THIS_MODULE,
        .open    = table_open2,
        .read    = seq_read,
        .write   = table_write2,
        .llseek  = seq_lseek,
        .release = seq_release
};

static const struct file_operations format3_fops = {
        .owner   = THIS_MODULE,
        .open    = table_open3,
        .read    = seq_read,
        .llseek  = seq_lseek,
        .release = seq_release
};

static const struct file_operations format4_fops = {
        .owner   = THIS_MODULE,
        .open    = table_open4,
        .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);
        ret = dlm_lock_recovery_try(ls);
        if (!ret) {
                rv = -EAGAIN;
                goto out;
        }

        spin_lock_bh(&ls->ls_waiters_lock);
        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\n",
                               lkb->lkb_id, lkb->lkb_wait_type,
                               lkb->lkb_nodeid, lkb->lkb_resource->res_name);
                if (ret >= len - pos)
                        break;
                pos += ret;
        }
        spin_unlock_bh(&ls->ls_waiters_lock);
        dlm_unlock_recovery(ls);

        rv = simple_read_from_buffer(userbuf, count, ppos, debug_buf, pos);
out:
        mutex_unlock(&debug_buf_lock);
        return rv;
}

static ssize_t waiters_write(struct file *file, const char __user *user_buf,
                             size_t count, loff_t *ppos)
{
        struct dlm_ls *ls = file->private_data;
        int mstype, to_nodeid;
        char buf[128] = {};
        uint32_t lkb_id;
        int n, error;

        if (copy_from_user(buf, user_buf,
                           min_t(size_t, sizeof(buf) - 1, count)))
                return -EFAULT;

        n = sscanf(buf, "%x %d %d", &lkb_id, &mstype, &to_nodeid);
        if (n != 3)
                return -EINVAL;

        error = dlm_lock_recovery_try(ls);
        if (!error)
                return -EAGAIN;

        error = dlm_debug_add_lkb_to_waiters(ls, lkb_id, mstype, to_nodeid);
        dlm_unlock_recovery(ls);
        if (error)
                return error;

        return count;
}

static const struct file_operations waiters_fops = {
        .owner   = THIS_MODULE,
        .open    = simple_open,
        .read    = waiters_read,
        .write   = waiters_write,
        .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);
        debugfs_remove(ls->ls_debug_queued_asts_dentry);
}

static int dlm_state_show(struct seq_file *file, void *offset)
{
        seq_printf(file, "%s\n", dlm_midcomms_state(file->private));
        return 0;
}
DEFINE_SHOW_ATTRIBUTE(dlm_state);

static int dlm_flags_show(struct seq_file *file, void *offset)
{
        seq_printf(file, "%lu\n", dlm_midcomms_flags(file->private));
        return 0;
}
DEFINE_SHOW_ATTRIBUTE(dlm_flags);

static int dlm_send_queue_cnt_show(struct seq_file *file, void *offset)
{
        seq_printf(file, "%d\n", dlm_midcomms_send_queue_cnt(file->private));
        return 0;
}
DEFINE_SHOW_ATTRIBUTE(dlm_send_queue_cnt);

static int dlm_version_show(struct seq_file *file, void *offset)
{
        seq_printf(file, "0x%08x\n", dlm_midcomms_version(file->private));
        return 0;
}
DEFINE_SHOW_ATTRIBUTE(dlm_version);

static ssize_t dlm_rawmsg_write(struct file *fp, const char __user *user_buf,
                                size_t count, loff_t *ppos)
{
        void *buf;
        int ret;

        if (count > PAGE_SIZE || count < sizeof(struct dlm_header))
                return -EINVAL;

        buf = kmalloc(PAGE_SIZE, GFP_NOFS);
        if (!buf)
                return -ENOMEM;

        if (copy_from_user(buf, user_buf, count)) {
                ret = -EFAULT;
                goto out;
        }

        ret = dlm_midcomms_rawmsg_send(fp->private_data, buf, count);
        if (ret)
                goto out;

        kfree(buf);
        return count;

out:
        kfree(buf);
        return ret;
}

static const struct file_operations dlm_rawmsg_fops = {
        .open   = simple_open,
        .write  = dlm_rawmsg_write,
};

void *dlm_create_debug_comms_file(int nodeid, void *data)
{
        struct dentry *d_node;
        char name[256];

        memset(name, 0, sizeof(name));
        snprintf(name, 256, "%d", nodeid);

        d_node = debugfs_create_dir(name, dlm_comms);
        debugfs_create_file("state", 0444, d_node, data, &dlm_state_fops);
        debugfs_create_file("flags", 0444, d_node, data, &dlm_flags_fops);
        debugfs_create_file("send_queue_count", 0444, d_node, data,
                            &dlm_send_queue_cnt_fops);
        debugfs_create_file("version", 0444, d_node, data, &dlm_version_fops);
        debugfs_create_file("rawmsg", 0200, d_node, data, &dlm_rawmsg_fops);

        return d_node;
}

void dlm_delete_debug_comms_file(void *ctx)
{
        debugfs_remove(ctx);
}

void dlm_create_debug_file(struct dlm_ls *ls)
{
        /* Reserve enough space for the longest file name */
        char name[DLM_LOCKSPACE_LEN + sizeof("_queued_asts")];

        /* format 1 */

        ls->ls_debug_rsb_dentry = debugfs_create_file(ls->ls_name,
                                                      S_IFREG | S_IRUGO,
                                                      dlm_root,
                                                      ls,
                                                      &format1_fops);

        /* format 2 */

        snprintf(name, sizeof(name), "%s_locks", ls->ls_name);

        ls->ls_debug_locks_dentry = debugfs_create_file(name,
                                                        0644,
                                                        dlm_root,
                                                        ls,
                                                        &format2_fops);

        /* format 3 */

        snprintf(name, sizeof(name), "%s_all", ls->ls_name);

        ls->ls_debug_all_dentry = debugfs_create_file(name,
                                                      S_IFREG | S_IRUGO,
                                                      dlm_root,
                                                      ls,
                                                      &format3_fops);

        /* format 4 */

        snprintf(name, sizeof(name), "%s_toss", ls->ls_name);

        ls->ls_debug_toss_dentry = debugfs_create_file(name,
                                                       S_IFREG | S_IRUGO,
                                                       dlm_root,
                                                       ls,
                                                       &format4_fops);

        snprintf(name, sizeof(name), "%s_waiters", ls->ls_name);

        ls->ls_debug_waiters_dentry = debugfs_create_file(name,
                                                          0644,
                                                          dlm_root,
                                                          ls,
                                                          &waiters_fops);
}

void __init dlm_register_debugfs(void)
{
        mutex_init(&debug_buf_lock);
        dlm_root = debugfs_create_dir("dlm", NULL);
        dlm_comms = debugfs_create_dir("comms", dlm_root);
}

void dlm_unregister_debugfs(void)
{
        debugfs_remove(dlm_root);
}