#define pr_fmt(fmt) "drbd debugfs: " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/stat.h>
#include <linux/list.h>

#include "drbd_int.h"
#include "drbd_req.h"
#include "drbd_debugfs.h"

static struct dentry *drbd_debugfs_root;
static struct dentry *drbd_debugfs_resources;
static struct dentry *drbd_debugfs_minors;

void drbd_debugfs_resource_add(struct drbd_resource *resource)
{
	struct dentry *dentry;
	if (!drbd_debugfs_resources)
		return;

	dentry = debugfs_create_dir(resource->name, drbd_debugfs_resources);
	if (IS_ERR_OR_NULL(dentry))
		goto fail;
	resource->debugfs_res = dentry;

	dentry = debugfs_create_dir("volumes", resource->debugfs_res);
	if (IS_ERR_OR_NULL(dentry))
		goto fail;
	resource->debugfs_res_volumes = dentry;

	dentry = debugfs_create_dir("connections", resource->debugfs_res);
	if (IS_ERR_OR_NULL(dentry))
		goto fail;
	resource->debugfs_res_connections = dentry;

	return;

fail:
	drbd_debugfs_resource_cleanup(resource);
	drbd_err(resource, "failed to create debugfs dentry\n");
}

static void drbd_debugfs_remove(struct dentry **dp)
{
	debugfs_remove(*dp);
	*dp = NULL;
}

void drbd_debugfs_resource_cleanup(struct drbd_resource *resource)
{
	/* it is ok to call debugfs_remove(NULL) */
	drbd_debugfs_remove(&resource->debugfs_res_in_flight_summary);
	drbd_debugfs_remove(&resource->debugfs_res_connections);
	drbd_debugfs_remove(&resource->debugfs_res_volumes);
	drbd_debugfs_remove(&resource->debugfs_res);
}

void drbd_debugfs_connection_add(struct drbd_connection *connection)
{
	struct dentry *conns_dir = connection->resource->debugfs_res_connections;
	struct dentry *dentry;
	if (!conns_dir)
		return;

	/* Once we enable mutliple peers,
	 * these connections will have descriptive names.
	 * For now, it is just the one connection to the (only) "peer". */
	dentry = debugfs_create_dir("peer", conns_dir);
	if (IS_ERR_OR_NULL(dentry))
		goto fail;
	connection->debugfs_conn = dentry;
	return;

fail:
	drbd_debugfs_connection_cleanup(connection);
	drbd_err(connection, "failed to create debugfs dentry\n");
}

void drbd_debugfs_connection_cleanup(struct drbd_connection *connection)
{
	drbd_debugfs_remove(&connection->debugfs_conn_callback_history);
	drbd_debugfs_remove(&connection->debugfs_conn_oldest_requests);
	drbd_debugfs_remove(&connection->debugfs_conn);
}

void drbd_debugfs_device_add(struct drbd_device *device)
{
	struct dentry *vols_dir = device->resource->debugfs_res_volumes;
	char minor_buf[8]; /* MINORMASK, MINORBITS == 20; */
	char vnr_buf[8];   /* volume number vnr is even 16 bit only; */
	char *slink_name = NULL;

	struct dentry *dentry;
	if (!vols_dir || !drbd_debugfs_minors)
		return;

	snprintf(vnr_buf, sizeof(vnr_buf), "%u", device->vnr);
	dentry = debugfs_create_dir(vnr_buf, vols_dir);
	if (IS_ERR_OR_NULL(dentry))
		goto fail;
	device->debugfs_vol = dentry;

	snprintf(minor_buf, sizeof(minor_buf), "%u", device->minor);
	slink_name = kasprintf(GFP_KERNEL, "../resources/%s/volumes/%u",
			device->resource->name, device->vnr);
	if (!slink_name)
		goto fail;
	dentry = debugfs_create_symlink(minor_buf, drbd_debugfs_minors, slink_name);
	if (IS_ERR_OR_NULL(dentry))
		goto fail;
	device->debugfs_minor = dentry;
	kfree(slink_name);

fail:
	drbd_debugfs_device_cleanup(device);
	drbd_err(device, "failed to create debugfs entries\n");
}

void drbd_debugfs_device_cleanup(struct drbd_device *device)
{
	drbd_debugfs_remove(&device->debugfs_minor);
	drbd_debugfs_remove(&device->debugfs_vol_oldest_requests);
	drbd_debugfs_remove(&device->debugfs_vol_act_log_extents);
	drbd_debugfs_remove(&device->debugfs_vol_resync_extents);
	drbd_debugfs_remove(&device->debugfs_vol_data_gen_id);
	drbd_debugfs_remove(&device->debugfs_vol);
}

void drbd_debugfs_peer_device_add(struct drbd_peer_device *peer_device)
{
	struct dentry *conn_dir = peer_device->connection->debugfs_conn;
	struct dentry *dentry;
	char vnr_buf[8];

	if (!conn_dir)
		return;

	snprintf(vnr_buf, sizeof(vnr_buf), "%u", peer_device->device->vnr);
	dentry = debugfs_create_dir(vnr_buf, conn_dir);
	if (IS_ERR_OR_NULL(dentry))
		goto fail;
	peer_device->debugfs_peer_dev = dentry;
	return;

fail:
	drbd_debugfs_peer_device_cleanup(peer_device);
	drbd_err(peer_device, "failed to create debugfs entries\n");
}

void drbd_debugfs_peer_device_cleanup(struct drbd_peer_device *peer_device)
{
	drbd_debugfs_remove(&peer_device->debugfs_peer_dev);
}

/* not __exit, may be indirectly called
 * from the module-load-failure path as well. */
void drbd_debugfs_cleanup(void)
{
	drbd_debugfs_remove(&drbd_debugfs_resources);
	drbd_debugfs_remove(&drbd_debugfs_minors);
	drbd_debugfs_remove(&drbd_debugfs_root);
}

int __init drbd_debugfs_init(void)
{
	struct dentry *dentry;

	dentry = debugfs_create_dir("drbd", NULL);
	if (IS_ERR_OR_NULL(dentry))
		goto fail;
	drbd_debugfs_root = dentry;

	dentry = debugfs_create_dir("resources", drbd_debugfs_root);
	if (IS_ERR_OR_NULL(dentry))
		goto fail;
	drbd_debugfs_resources = dentry;

	dentry = debugfs_create_dir("minors", drbd_debugfs_root);
	if (IS_ERR_OR_NULL(dentry))
		goto fail;
	drbd_debugfs_minors = dentry;
	return 0;

fail:
	drbd_debugfs_cleanup();
	if (dentry)
		return PTR_ERR(dentry);
	else
		return -EINVAL;
}