[PATCH 6/7] dlm: debug fs

[David Teigland]

A CONFIG setting optionally adds this file which creates a debugfs file
for each lockspace: /debug/dlm/<lockspace_name>.  Reading the debugfs file
displays all resources/locks currently managed in the given lockspace.

Signed-Off-By: Dave Teigland <teigland@xxxxxxxxxx>
Signed-Off-By: Patrick Caulfield <pcaulfie@xxxxxxxxxx>

---

 drivers/dlm/debug_fs.c |  304 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 304 insertions(+)

--- a/drivers/dlm/debug_fs.c	1970-01-01 07:30:00.000000000 +0730
+++ b/drivers/dlm/debug_fs.c	2005-04-25 22:52:03.738849896 +0800
@@ -0,0 +1,304 @@
+/******************************************************************************
+*******************************************************************************
+**
+**  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_range) {
+		/* FIXME: this warns on Alpha */
+		if (lkb->lkb_status == DLM_LKSTS_CONVERT
+		    || lkb->lkb_status == DLM_LKSTS_GRANTED)
+			seq_printf(s, " %" PRIx64 "-%" PRIx64,
+				   lkb->lkb_range[GR_RANGE_START],
+				   lkb->lkb_range[GR_RANGE_END]);
+		if (lkb->lkb_status == DLM_LKSTS_CONVERT
+		    || lkb->lkb_status == DLM_LKSTS_WAITING)
+			seq_printf(s, " (%" PRIx64 "-%" PRIx64 ")",
+				   lkb->lkb_range[RQ_RANGE_START],
+				   lkb->lkb_range[RQ_RANGE_END]);
+	}
+
+	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;
+
+	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)
+		seq_printf(s, "\"  \nLocal Copy, Master is node %d\n",
+			   res->res_nodeid);
+	else
+		seq_printf(s, "\"  \nMaster Copy\n");
+
+	/* Print the LVB: */
+	if (res->res_lvbptr) {
+		seq_printf(s, "LVB: ");
+		for (i = 0; i < DLM_LVB_LEN; i++) {
+			if (i == DLM_LVB_LEN / 2)
+				seq_printf(s, "\n     ");
+			seq_printf(s, "%02x ",
+				   (unsigned char) res->res_lvbptr[i]);
+		}
+		if (test_bit(RESFL_VALNOTVALID, &res->res_flags))
+			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;
+
+ top:
+	if (!ri->next) {
+		/* 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);
+}
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