/*
 *  Device operations for the pnfs nfs4 file layout driver.
 *
 *  Copyright (c) 2002
 *  The Regents of the University of Michigan
 *  All Rights Reserved
 *
 *  Dean Hildebrand <dhildebz@umich.edu>
 *  Garth Goodson   <Garth.Goodson@netapp.com>
 *
 *  Permission is granted to use, copy, create derivative works, and
 *  redistribute this software and such derivative works for any purpose,
 *  so long as the name of the University of Michigan is not used in
 *  any advertising or publicity pertaining to the use or distribution
 *  of this software without specific, written prior authorization. If
 *  the above copyright notice or any other identification of the
 *  University of Michigan is included in any copy of any portion of
 *  this software, then the disclaimer below must also be included.
 *
 *  This software is provided as is, without representation or warranty
 *  of any kind either express or implied, including without limitation
 *  the implied warranties of merchantability, fitness for a particular
 *  purpose, or noninfringement.  The Regents of the University of
 *  Michigan shall not be liable for any damages, including special,
 *  indirect, incidental, or consequential damages, with respect to any
 *  claim arising out of or in connection with the use of the software,
 *  even if it has been or is hereafter advised of the possibility of
 *  such damages.
 */

#include <linux/nfs_fs.h>
#include <linux/vmalloc.h>

#include "internal.h"
#include "nfs4filelayout.h"

#define NFSDBG_FACILITY		NFSDBG_PNFS_LD

/*
 * Data server cache
 *
 * Data servers can be mapped to different device ids.
 * nfs4_pnfs_ds reference counting
 *   - set to 1 on allocation
 *   - incremented when a device id maps a data server already in the cache.
 *   - decremented when deviceid is removed from the cache.
 */
DEFINE_SPINLOCK(nfs4_ds_cache_lock);
static LIST_HEAD(nfs4_data_server_cache);

/* Debug routines */
void
print_ds(struct nfs4_pnfs_ds *ds)
{
	if (ds == NULL) {
		printk("%s NULL device\n", __func__);
		return;
	}
	printk("        ip_addr %x port %hu\n"
		"        ref count %d\n"
		"        client %p\n"
		"        cl_exchange_flags %x\n",
		ntohl(ds->ds_ip_addr), ntohs(ds->ds_port),
		atomic_read(&ds->ds_count), ds->ds_clp,
		ds->ds_clp ? ds->ds_clp->cl_exchange_flags : 0);
}

void
print_ds_list(struct nfs4_file_layout_dsaddr *dsaddr)
{
	int i;

	ifdebug(FACILITY) {
		printk("%s dsaddr->ds_num %d\n", __func__,
		       dsaddr->ds_num);
		for (i = 0; i < dsaddr->ds_num; i++)
			print_ds(dsaddr->ds_list[i]);
	}
}

void print_deviceid(struct nfs4_deviceid *id)
{
	u32 *p = (u32 *)id;

	dprintk("%s: device id= [%x%x%x%x]\n", __func__,
		p[0], p[1], p[2], p[3]);
}

/* nfs4_ds_cache_lock is held */
static struct nfs4_pnfs_ds *
_data_server_lookup_locked(u32 ip_addr, u32 port)
{
	struct nfs4_pnfs_ds *ds;

	dprintk("_data_server_lookup: ip_addr=%x port=%hu\n",
			ntohl(ip_addr), ntohs(port));

	list_for_each_entry(ds, &nfs4_data_server_cache, ds_node) {
		if (ds->ds_ip_addr == ip_addr &&
		    ds->ds_port == port) {
			return ds;
		}
	}
	return NULL;
}

static void
destroy_ds(struct nfs4_pnfs_ds *ds)
{
	dprintk("--> %s\n", __func__);
	ifdebug(FACILITY)
		print_ds(ds);

	if (ds->ds_clp)
		nfs_put_client(ds->ds_clp);
	kfree(ds);
}

static void
nfs4_fl_free_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
{
	struct nfs4_pnfs_ds *ds;
	int i;

	print_deviceid(&dsaddr->deviceid.de_id);

	for (i = 0; i < dsaddr->ds_num; i++) {
		ds = dsaddr->ds_list[i];
		if (ds != NULL) {
			if (atomic_dec_and_lock(&ds->ds_count,
						&nfs4_ds_cache_lock)) {
				list_del_init(&ds->ds_node);
				spin_unlock(&nfs4_ds_cache_lock);
				destroy_ds(ds);
			}
		}
	}
	kfree(dsaddr->stripe_indices);
	kfree(dsaddr);
}

void
nfs4_fl_free_deviceid_callback(struct pnfs_deviceid_node *device)
{
	struct nfs4_file_layout_dsaddr *dsaddr =
		container_of(device, struct nfs4_file_layout_dsaddr, deviceid);

	nfs4_fl_free_deviceid(dsaddr);
}

static struct nfs4_pnfs_ds *
nfs4_pnfs_ds_add(struct inode *inode, u32 ip_addr, u32 port)
{
	struct nfs4_pnfs_ds *tmp_ds, *ds;

	ds = kzalloc(sizeof(*tmp_ds), GFP_KERNEL);
	if (!ds)
		goto out;

	spin_lock(&nfs4_ds_cache_lock);
	tmp_ds = _data_server_lookup_locked(ip_addr, port);
	if (tmp_ds == NULL) {
		ds->ds_ip_addr = ip_addr;
		ds->ds_port = port;
		atomic_set(&ds->ds_count, 1);
		INIT_LIST_HEAD(&ds->ds_node);
		ds->ds_clp = NULL;
		list_add(&ds->ds_node, &nfs4_data_server_cache);
		dprintk("%s add new data server ip 0x%x\n", __func__,
			ds->ds_ip_addr);
	} else {
		kfree(ds);
		atomic_inc(&tmp_ds->ds_count);
		dprintk("%s data server found ip 0x%x, inc'ed ds_count to %d\n",
			__func__, tmp_ds->ds_ip_addr,
			atomic_read(&tmp_ds->ds_count));
		ds = tmp_ds;
	}
	spin_unlock(&nfs4_ds_cache_lock);
out:
	return ds;
}

/*
 * Currently only support ipv4, and one multi-path address.
 */
static struct nfs4_pnfs_ds *
decode_and_add_ds(__be32 **pp, struct inode *inode)
{
	struct nfs4_pnfs_ds *ds = NULL;
	char *buf;
	const char *ipend, *pstr;
	u32 ip_addr, port;
	int nlen, rlen, i;
	int tmp[2];
	__be32 *r_netid, *r_addr, *p = *pp;

	/* r_netid */
	nlen = be32_to_cpup(p++);
	r_netid = p;
	p += XDR_QUADLEN(nlen);

	/* r_addr */
	rlen = be32_to_cpup(p++);
	r_addr = p;
	p += XDR_QUADLEN(rlen);
	*pp = p;

	/* Check that netid is "tcp" */
	if (nlen != 3 ||  memcmp((char *)r_netid, "tcp", 3)) {
		dprintk("%s: ERROR: non ipv4 TCP r_netid\n", __func__);
		goto out_err;
	}

	/* ipv6 length plus port is legal */
	if (rlen > INET6_ADDRSTRLEN + 8) {
		dprintk("%s: Invalid address, length %d\n", __func__,
			rlen);
		goto out_err;
	}
	buf = kmalloc(rlen + 1, GFP_KERNEL);
	if (!buf) {
		dprintk("%s: Not enough memory\n", __func__);
		goto out_err;
	}
	buf[rlen] = '\0';
	memcpy(buf, r_addr, rlen);

	/* replace the port dots with dashes for the in4_pton() delimiter*/
	for (i = 0; i < 2; i++) {
		char *res = strrchr(buf, '.');
		if (!res) {
			dprintk("%s: Failed finding expected dots in port\n",
				__func__);
			goto out_free;
		}
		*res = '-';
	}

	/* Currently only support ipv4 address */
	if (in4_pton(buf, rlen, (u8 *)&ip_addr, '-', &ipend) == 0) {
		dprintk("%s: Only ipv4 addresses supported\n", __func__);
		goto out_free;
	}

	/* port */
	pstr = ipend;
	sscanf(pstr, "-%d-%d", &tmp[0], &tmp[1]);
	port = htons((tmp[0] << 8) | (tmp[1]));

	ds = nfs4_pnfs_ds_add(inode, ip_addr, port);
	dprintk("%s: Decoded address and port %s\n", __func__, buf);
out_free:
	kfree(buf);
out_err:
	return ds;
}

/* Decode opaque device data and return the result */
static struct nfs4_file_layout_dsaddr*
decode_device(struct inode *ino, struct pnfs_device *pdev)
{
	int i, dummy;
	u32 cnt, num;
	u8 *indexp;
	__be32 *p = (__be32 *)pdev->area, *indicesp;
	struct nfs4_file_layout_dsaddr *dsaddr;

	/* Get the stripe count (number of stripe index) */
	cnt = be32_to_cpup(p++);
	dprintk("%s stripe count  %d\n", __func__, cnt);
	if (cnt > NFS4_PNFS_MAX_STRIPE_CNT) {
		printk(KERN_WARNING "%s: stripe count %d greater than "
		       "supported maximum %d\n", __func__,
			cnt, NFS4_PNFS_MAX_STRIPE_CNT);
		goto out_err;
	}

	/* Check the multipath list count */
	indicesp = p;
	p += XDR_QUADLEN(cnt << 2);
	num = be32_to_cpup(p++);
	dprintk("%s ds_num %u\n", __func__, num);
	if (num > NFS4_PNFS_MAX_MULTI_CNT) {
		printk(KERN_WARNING "%s: multipath count %d greater than "
			"supported maximum %d\n", __func__,
			num, NFS4_PNFS_MAX_MULTI_CNT);
		goto out_err;
	}
	dsaddr = kzalloc(sizeof(*dsaddr) +
			(sizeof(struct nfs4_pnfs_ds *) * (num - 1)),
			GFP_KERNEL);
	if (!dsaddr)
		goto out_err;

	dsaddr->stripe_indices = kzalloc(sizeof(u8) * cnt, GFP_KERNEL);
	if (!dsaddr->stripe_indices)
		goto out_err_free;

	dsaddr->stripe_count = cnt;
	dsaddr->ds_num = num;

	memcpy(&dsaddr->deviceid.de_id, &pdev->dev_id, sizeof(pdev->dev_id));

	/* Go back an read stripe indices */
	p = indicesp;
	indexp = &dsaddr->stripe_indices[0];
	for (i = 0; i < dsaddr->stripe_count; i++) {
		*indexp = be32_to_cpup(p++);
		if (*indexp >= num)
			goto out_err_free;
		indexp++;
	}
	/* Skip already read multipath list count */
	p++;

	for (i = 0; i < dsaddr->ds_num; i++) {
		int j;

		dummy = be32_to_cpup(p++); /* multipath count */
		if (dummy > 1) {
			printk(KERN_WARNING
			       "%s: Multipath count %d not supported, "
			       "skipping all greater than 1\n", __func__,
				dummy);
		}
		for (j = 0; j < dummy; j++) {
			if (j == 0) {
				dsaddr->ds_list[i] = decode_and_add_ds(&p, ino);
				if (dsaddr->ds_list[i] == NULL)
					goto out_err_free;
			} else {
				u32 len;
				/* skip extra multipath */
				len = be32_to_cpup(p++);
				p += XDR_QUADLEN(len);
				len = be32_to_cpup(p++);
				p += XDR_QUADLEN(len);
				continue;
			}
		}
	}
	return dsaddr;

out_err_free:
	nfs4_fl_free_deviceid(dsaddr);
out_err:
	dprintk("%s ERROR: returning NULL\n", __func__);
	return NULL;
}

/*
 * Decode the opaque device specified in 'dev'
 * and add it to the list of available devices.
 * If the deviceid is already cached, nfs4_add_deviceid will return
 * a pointer to the cached struct and throw away the new.
 */
static struct nfs4_file_layout_dsaddr*
decode_and_add_device(struct inode *inode, struct pnfs_device *dev)
{
	struct nfs4_file_layout_dsaddr *dsaddr;
	struct pnfs_deviceid_node *d;

	dsaddr = decode_device(inode, dev);
	if (!dsaddr) {
		printk(KERN_WARNING "%s: Could not decode or add device\n",
			__func__);
		return NULL;
	}

	d = pnfs_add_deviceid(NFS_SERVER(inode)->nfs_client->cl_devid_cache,
			      &dsaddr->deviceid);

	return container_of(d, struct nfs4_file_layout_dsaddr, deviceid);
}

/*
 * Retrieve the information for dev_id, add it to the list
 * of available devices, and return it.
 */
struct nfs4_file_layout_dsaddr *
get_device_info(struct inode *inode, struct nfs4_deviceid *dev_id)
{
	struct pnfs_device *pdev = NULL;
	u32 max_resp_sz;
	int max_pages;
	struct page **pages = NULL;
	struct nfs4_file_layout_dsaddr *dsaddr = NULL;
	int rc, i;
	struct nfs_server *server = NFS_SERVER(inode);

	/*
	 * Use the session max response size as the basis for setting
	 * GETDEVICEINFO's maxcount
	 */
	max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
	max_pages = max_resp_sz >> PAGE_SHIFT;
	dprintk("%s inode %p max_resp_sz %u max_pages %d\n",
		__func__, inode, max_resp_sz, max_pages);

	pdev = kzalloc(sizeof(struct pnfs_device), GFP_KERNEL);
	if (pdev == NULL)
		return NULL;

	pages = kzalloc(max_pages * sizeof(struct page *), GFP_KERNEL);
	if (pages == NULL) {
		kfree(pdev);
		return NULL;
	}
	for (i = 0; i < max_pages; i++) {
		pages[i] = alloc_page(GFP_KERNEL);
		if (!pages[i])
			goto out_free;
	}

	/* set pdev->area */
	pdev->area = vmap(pages, max_pages, VM_MAP, PAGE_KERNEL);
	if (!pdev->area)
		goto out_free;

	memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
	pdev->layout_type = LAYOUT_NFSV4_1_FILES;
	pdev->pages = pages;
	pdev->pgbase = 0;
	pdev->pglen = PAGE_SIZE * max_pages;
	pdev->mincount = 0;

	rc = nfs4_proc_getdeviceinfo(server, pdev);
	dprintk("%s getdevice info returns %d\n", __func__, rc);
	if (rc)
		goto out_free;

	/*
	 * Found new device, need to decode it and then add it to the
	 * list of known devices for this mountpoint.
	 */
	dsaddr = decode_and_add_device(inode, pdev);
out_free:
	if (pdev->area != NULL)
		vunmap(pdev->area);
	for (i = 0; i < max_pages; i++)
		__free_page(pages[i]);
	kfree(pages);
	kfree(pdev);
	dprintk("<-- %s dsaddr %p\n", __func__, dsaddr);
	return dsaddr;
}

struct nfs4_file_layout_dsaddr *
nfs4_fl_find_get_deviceid(struct nfs_client *clp, struct nfs4_deviceid *id)
{
	struct pnfs_deviceid_node *d;

	d = pnfs_find_get_deviceid(clp->cl_devid_cache, id);
	return (d == NULL) ? NULL :
		container_of(d, struct nfs4_file_layout_dsaddr, deviceid);
}