linux/fs/dlm/debug_fs.c

/******************************************************************************
*******************************************************************************
**
**  Copyright (C) 2005 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 "dlm_internal.h"


static struct dentry *dlm_root;

struct rsb_iter {
	int entry;
	struct dlm_ls *ls;
	struct list_head *next;
	struct dlm_rsb *rsb;
};

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_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_printf(s, "\n");
}

static int print_resource(struct dlm_rsb *res, struct seq_file *s)
{
	struct dlm_lkb *lkb;
	int i, lvblen = res->res_ls->ls_lvblen;

	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_printf(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);

	/* Print the LVB: */
	if (res->res_lvbptr) {
		seq_printf(s, "LVB: ");
		for (i = 0; i < lvblen; i++) {
			if (i == lvblen / 2)
				seq_printf(s, "\n     ");
			seq_printf(s, "%02x ",
				   (unsigned char) res->res_lvbptr[i]);
		}
		if (rsb_flag(res, RSB_VALNOTVALID))
			seq_printf(s, " (INVALID)");
		seq_printf(s, "\n");
	}

	/* Print the locks attached to this resource */
	seq_printf(s, "Granted Queue\n");
	list_for_each_entry(lkb, &res->res_grantqueue, lkb_statequeue)
		print_lock(s, lkb, res);

	seq_printf(s, "Conversion Queue\n");
	list_for_each_entry(lkb, &res->res_convertqueue, lkb_statequeue)
		print_lock(s, lkb, res);

	seq_printf(s, "Waiting Queue\n");
	list_for_each_entry(lkb, &res->res_waitqueue, lkb_statequeue)
		print_lock(s, lkb, res);

	return 0;
}

static int rsb_iter_next(struct rsb_iter *ri)
{
	struct dlm_ls *ls = ri->ls;
	int i;

	if (!ri->next) {
 top:
		/* Find the next non-empty hash bucket */
		for (i = ri->entry; i < ls->ls_rsbtbl_size; i++) {
			read_lock(&ls->ls_rsbtbl[i].lock);
			if (!list_empty(&ls->ls_rsbtbl[i].list)) {
				ri->next = ls->ls_rsbtbl[i].list.next;
				read_unlock(&ls->ls_rsbtbl[i].lock);
				break;
			}
			read_unlock(&ls->ls_rsbtbl[i].lock);
                }
		ri->entry = i;

		if (ri->entry >= ls->ls_rsbtbl_size)
			return 1;
	} else {
		i = ri->entry;
		read_lock(&ls->ls_rsbtbl[i].lock);
		ri->next = ri->next->next;
		if (ri->next->next == ls->ls_rsbtbl[i].list.next) {
			/* End of list - move to next bucket */
			ri->next = NULL;
			ri->entry++;
			read_unlock(&ls->ls_rsbtbl[i].lock);
			goto top;
                }
		read_unlock(&ls->ls_rsbtbl[i].lock);
	}
	ri->rsb = list_entry(ri->next, struct dlm_rsb, res_hashchain);

	return 0;
}

static void rsb_iter_free(struct rsb_iter *ri)
{
	kfree(ri);
}

static struct rsb_iter *rsb_iter_init(struct dlm_ls *ls)
{
	struct rsb_iter *ri;

	ri = kmalloc(sizeof *ri, GFP_KERNEL);
	if (!ri)
		return NULL;

	ri->ls = ls;
	ri->entry = 0;
	ri->next = NULL;

	if (rsb_iter_next(ri)) {
		rsb_iter_free(ri);
		return NULL;
	}

	return ri;
}

static void *seq_start(struct seq_file *file, loff_t *pos)
{
	struct rsb_iter *ri;
	loff_t n = *pos;

	ri = rsb_iter_init(file->private);
	if (!ri)
		return NULL;

	while (n--) {
		if (rsb_iter_next(ri)) {
			rsb_iter_free(ri);
			return NULL;
		}
	}

	return ri;
}

static void *seq_next(struct seq_file *file, void *iter_ptr, loff_t *pos)
{
	struct rsb_iter *ri = iter_ptr;

	(*pos)++;

	if (rsb_iter_next(ri)) {
		rsb_iter_free(ri);
		return NULL;
	}

	return ri;
}

static void seq_stop(struct seq_file *file, void *iter_ptr)
{
	/* nothing for now */
}

static int seq_show(struct seq_file *file, void *iter_ptr)
{
	struct rsb_iter *ri = iter_ptr;

	print_resource(ri->rsb, file);

	return 0;
}

static struct seq_operations dlm_seq_ops = {
	.start = seq_start,
	.next  = seq_next,
	.stop  = seq_stop,
	.show  = seq_show,
};

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

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

	seq = file->private_data;
	seq->private = inode->u.generic_ip;

	return 0;
}

static struct file_operations dlm_fops = {
	.owner   = THIS_MODULE,
	.open    = do_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release
};

int dlm_create_debug_file(struct dlm_ls *ls)
{
	ls->ls_debug_dentry = debugfs_create_file(ls->ls_name,
						  S_IFREG | S_IRUGO,
						  dlm_root,
						  ls,
						  &dlm_fops);
	return ls->ls_debug_dentry ? 0 : -ENOMEM;
}

void dlm_delete_debug_file(struct dlm_ls *ls)
{
	if (ls->ls_debug_dentry)
		debugfs_remove(ls->ls_debug_dentry);
}

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

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