/*
 *  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 <linux/module.h>

#include "../internal.h"
#include "../nfs4session.h"
#include "filelayout.h"
#include "../nfs4trace.h"

#define NFSDBG_FACILITY         NFSDBG_PNFS_LD

static unsigned int dataserver_timeo = NFS4_DEF_DS_TIMEO;
static unsigned int dataserver_retrans = NFS4_DEF_DS_RETRANS;

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

        nfs4_print_deviceid(&dsaddr->id_node.deviceid);

        for (i = 0; i < dsaddr->ds_num; i++) {
                ds = dsaddr->ds_list[i];
                if (ds != NULL)
                        nfs4_pnfs_ds_put(ds);
        }
        kfree(dsaddr->stripe_indices);
        kfree_rcu(dsaddr, id_node.rcu);
}

/* Decode opaque device data and return the result */
struct nfs4_file_layout_dsaddr *
nfs4_fl_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev,
                gfp_t gfp_flags)
{
        int i;
        u32 cnt, num;
        u8 *indexp;
        __be32 *p;
        u8 *stripe_indices;
        u8 max_stripe_index;
        struct nfs4_file_layout_dsaddr *dsaddr = NULL;
        struct xdr_stream stream;
        struct xdr_buf buf;
        struct folio *scratch;
        struct list_head dsaddrs;
        struct nfs4_pnfs_ds_addr *da;
        struct net *net = server->nfs_client->cl_net;

        /* set up xdr stream */
        scratch = folio_alloc(gfp_flags, 0);
        if (!scratch)
                goto out_err;

        xdr_init_decode_pages(&stream, &buf, pdev->pages, pdev->pglen);
        xdr_set_scratch_folio(&stream, scratch);

        /* Get the stripe count (number of stripe index) */
        p = xdr_inline_decode(&stream, 4);
        if (unlikely(!p))
                goto out_err_free_scratch;

        cnt = be32_to_cpup(p);
        dprintk("%s stripe count  %d\n", __func__, cnt);
        if (cnt > NFS4_PNFS_MAX_STRIPE_CNT) {
                printk(KERN_WARNING "NFS: %s: stripe count %d greater than "
                       "supported maximum %d\n", __func__,
                        cnt, NFS4_PNFS_MAX_STRIPE_CNT);
                goto out_err_free_scratch;
        }

        /* read stripe indices */
        stripe_indices = kcalloc(cnt, sizeof(u8), gfp_flags);
        if (!stripe_indices)
                goto out_err_free_scratch;

        p = xdr_inline_decode(&stream, cnt << 2);
        if (unlikely(!p))
                goto out_err_free_stripe_indices;

        indexp = &stripe_indices[0];
        max_stripe_index = 0;
        for (i = 0; i < cnt; i++) {
                *indexp = be32_to_cpup(p++);
                max_stripe_index = max(max_stripe_index, *indexp);
                indexp++;
        }

        /* Check the multipath list count */
        p = xdr_inline_decode(&stream, 4);
        if (unlikely(!p))
                goto out_err_free_stripe_indices;

        num = be32_to_cpup(p);
        dprintk("%s ds_num %u\n", __func__, num);
        if (num > NFS4_PNFS_MAX_MULTI_CNT) {
                printk(KERN_WARNING "NFS: %s: multipath count %d greater than "
                        "supported maximum %d\n", __func__,
                        num, NFS4_PNFS_MAX_MULTI_CNT);
                goto out_err_free_stripe_indices;
        }

        /* validate stripe indices are all < num */
        if (max_stripe_index >= num) {
                printk(KERN_WARNING "NFS: %s: stripe index %u >= num ds %u\n",
                        __func__, max_stripe_index, num);
                goto out_err_free_stripe_indices;
        }

        dsaddr = kzalloc_flex(*dsaddr, ds_list, num, gfp_flags);
        if (!dsaddr)
                goto out_err_free_stripe_indices;

        dsaddr->stripe_count = cnt;
        dsaddr->stripe_indices = stripe_indices;
        stripe_indices = NULL;
        dsaddr->ds_num = num;
        nfs4_init_deviceid_node(&dsaddr->id_node, server, &pdev->dev_id);

        INIT_LIST_HEAD(&dsaddrs);

        for (i = 0; i < dsaddr->ds_num; i++) {
                int j;
                u32 mp_count;

                p = xdr_inline_decode(&stream, 4);
                if (unlikely(!p))
                        goto out_err_free_deviceid;

                mp_count = be32_to_cpup(p); /* multipath count */
                for (j = 0; j < mp_count; j++) {
                        da = nfs4_decode_mp_ds_addr(net, &stream, gfp_flags);
                        if (da)
                                list_add_tail(&da->da_node, &dsaddrs);
                }
                if (list_empty(&dsaddrs)) {
                        dprintk("%s: no suitable DS addresses found\n",
                                __func__);
                        goto out_err_free_deviceid;
                }

                dsaddr->ds_list[i] = nfs4_pnfs_ds_add(net, &dsaddrs, gfp_flags);
                if (!dsaddr->ds_list[i])
                        goto out_err_drain_dsaddrs;
                trace_fl_getdevinfo(server, &pdev->dev_id, dsaddr->ds_list[i]->ds_remotestr);

                /* If DS was already in cache, free ds addrs */
                while (!list_empty(&dsaddrs)) {
                        da = list_first_entry(&dsaddrs,
                                              struct nfs4_pnfs_ds_addr,
                                              da_node);
                        list_del_init(&da->da_node);
                        kfree(da->da_remotestr);
                        kfree(da);
                }
        }

        folio_put(scratch);
        return dsaddr;

out_err_drain_dsaddrs:
        while (!list_empty(&dsaddrs)) {
                da = list_first_entry(&dsaddrs, struct nfs4_pnfs_ds_addr,
                                      da_node);
                list_del_init(&da->da_node);
                kfree(da->da_remotestr);
                kfree(da);
        }
out_err_free_deviceid:
        nfs4_fl_free_deviceid(dsaddr);
        /* stripe_indicies was part of dsaddr */
        goto out_err_free_scratch;
out_err_free_stripe_indices:
        kfree(stripe_indices);
out_err_free_scratch:
        folio_put(scratch);
out_err:
        dprintk("%s ERROR: returning NULL\n", __func__);
        return NULL;
}

void
nfs4_fl_put_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
{
        nfs4_put_deviceid_node(&dsaddr->id_node);
}

/*
 * Want res = (offset - layout->pattern_offset)/ layout->stripe_unit
 * Then: ((res + fsi) % dsaddr->stripe_count)
 */
u32
nfs4_fl_calc_j_index(struct pnfs_layout_segment *lseg, loff_t offset)
{
        struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
        u64 tmp;

        tmp = offset - flseg->pattern_offset;
        do_div(tmp, flseg->stripe_unit);
        tmp += flseg->first_stripe_index;
        return do_div(tmp, flseg->dsaddr->stripe_count);
}

u32
nfs4_fl_calc_ds_index(struct pnfs_layout_segment *lseg, u32 j)
{
        return FILELAYOUT_LSEG(lseg)->dsaddr->stripe_indices[j];
}

struct nfs_fh *
nfs4_fl_select_ds_fh(struct pnfs_layout_segment *lseg, u32 j)
{
        struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
        u32 i;

        if (flseg->stripe_type == STRIPE_SPARSE) {
                if (flseg->num_fh == 1)
                        i = 0;
                else if (flseg->num_fh == 0)
                        /* Use the MDS OPEN fh set in nfs_read_rpcsetup */
                        return NULL;
                else
                        i = nfs4_fl_calc_ds_index(lseg, j);
        } else
                i = j;
        return flseg->fh_array[i];
}

/* Upon return, either ds is connected, or ds is NULL */
struct nfs4_pnfs_ds *
nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx)
{
        struct nfs4_file_layout_dsaddr *dsaddr = FILELAYOUT_LSEG(lseg)->dsaddr;
        struct nfs4_pnfs_ds *ds = dsaddr->ds_list[ds_idx];
        struct nfs4_deviceid_node *devid = FILELAYOUT_DEVID_NODE(lseg);
        struct nfs4_pnfs_ds *ret = ds;
        struct nfs_server *s = NFS_SERVER(lseg->pls_layout->plh_inode);
        int status;

        if (ds == NULL) {
                printk(KERN_ERR "NFS: %s: No data server for offset index %d\n",
                        __func__, ds_idx);
                pnfs_generic_mark_devid_invalid(devid);
                goto out;
        }
        smp_rmb();
        if (ds->ds_clp)
                goto out_test_devid;

        status = nfs4_pnfs_ds_connect(s, ds, devid, dataserver_timeo,
                             dataserver_retrans, 4,
                             s->nfs_client->cl_minorversion);
        if (status) {
                nfs4_mark_deviceid_unavailable(devid);
                ret = NULL;
                goto out;
        }

out_test_devid:
        if (ret->ds_clp == NULL ||
            filelayout_test_devid_unavailable(devid))
                ret = NULL;
out:
        return ret;
}

module_param(dataserver_retrans, uint, 0644);
MODULE_PARM_DESC(dataserver_retrans, "The  number of times the NFSv4.1 client "
                        "retries a request before it attempts further "
                        " recovery  action.");
module_param(dataserver_timeo, uint, 0644);
MODULE_PARM_DESC(dataserver_timeo, "The time (in tenths of a second) the "
                        "NFSv4.1  client  waits for a response from a "
                        " data server before it retries an NFS request.");