// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2016 Tom Haynes <loghyr@primarydata.com>
 *
 * The following implements a super-simple flex-file server
 * where the NFSv4.1 mds is also the ds. And the storage is
 * the same. I.e., writing to the mds via a NFSv4.1 WRITE
 * goes to the same location as the NFSv3 WRITE.
 */
#include <linux/slab.h>

#include <linux/nfsd/debug.h>

#include <linux/sunrpc/addr.h>

#include "flexfilelayoutxdr.h"
#include "pnfs.h"
#include "vfs.h"

#define NFSDDBG_FACILITY        NFSDDBG_PNFS

static __be32
nfsd4_ff_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode,
                const struct svc_fh *fhp, struct nfsd4_layoutget *args)
{
        struct nfsd4_layout_seg *seg = &args->lg_seg;
        u32 device_generation = 0;
        int error;
        uid_t u;

        struct pnfs_ff_layout *fl;

        /*
         * The super simple flex file server has 1 mirror, 1 data server,
         * and 1 file handle. So instead of 4 allocs, do 1 for now.
         * Zero it out for the stateid - don't want junk in there!
         */
        error = -ENOMEM;
        fl = kzalloc_obj(*fl);
        if (!fl)
                goto out_error;
        args->lg_content = fl;

        /*
         * Avoid layout commit, try to force the I/O to the DS,
         * and for fun, cause all IOMODE_RW layout segments to
         * effectively be WRITE only.
         */
        fl->flags = FF_FLAGS_NO_LAYOUTCOMMIT | FF_FLAGS_NO_IO_THRU_MDS |
                    FF_FLAGS_NO_READ_IO;

        /* Do not allow a IOMODE_READ segment to have write pemissions */
        if (seg->iomode == IOMODE_READ) {
                u = from_kuid(&init_user_ns, inode->i_uid) + 1;
                fl->uid = make_kuid(&init_user_ns, u);
        } else
                fl->uid = inode->i_uid;
        fl->gid = inode->i_gid;

        error = nfsd4_set_deviceid(&fl->deviceid, fhp, device_generation);
        if (error)
                goto out_error;

        fl->fh.size = fhp->fh_handle.fh_size;
        memcpy(fl->fh.data, &fhp->fh_handle.fh_raw, fl->fh.size);

        /* Give whole file layout segments */
        seg->offset = 0;
        seg->length = NFS4_MAX_UINT64;

        dprintk("GET: 0x%llx:0x%llx %d\n", seg->offset, seg->length,
                seg->iomode);
        return 0;

out_error:
        seg->length = 0;
        return nfserrno(error);
}

static __be32
nfsd4_ff_proc_getdeviceinfo(struct super_block *sb, struct svc_rqst *rqstp,
                struct nfs4_client *clp, struct nfsd4_getdeviceinfo *gdp)
{
        struct pnfs_ff_device_addr *da;

        u16 port;
        char addr[INET6_ADDRSTRLEN];

        da = kzalloc_obj(struct pnfs_ff_device_addr);
        if (!da)
                return nfserrno(-ENOMEM);

        gdp->gd_device = da;

        da->version = 3;
        da->minor_version = 0;

        da->rsize = svc_max_payload(rqstp);
        da->wsize = da->rsize;

        rpc_ntop((struct sockaddr *)&rqstp->rq_daddr,
                 addr, INET6_ADDRSTRLEN);
        if (rqstp->rq_daddr.ss_family == AF_INET) {
                struct sockaddr_in *sin;

                sin = (struct sockaddr_in *)&rqstp->rq_daddr;
                port = ntohs(sin->sin_port);
                snprintf(da->netaddr.netid, FF_NETID_LEN + 1, "tcp");
                da->netaddr.netid_len = 3;
        } else {
                struct sockaddr_in6 *sin6;

                sin6 = (struct sockaddr_in6 *)&rqstp->rq_daddr;
                port = ntohs(sin6->sin6_port);
                snprintf(da->netaddr.netid, FF_NETID_LEN + 1, "tcp6");
                da->netaddr.netid_len = 4;
        }

        da->netaddr.addr_len =
                snprintf(da->netaddr.addr, FF_ADDR_LEN + 1,
                         "%s.%d.%d", addr, port >> 8, port & 0xff);

        da->tightly_coupled = false;

        return 0;
}

static __be32
nfsd4_ff_proc_layoutcommit(struct inode *inode, struct svc_rqst *rqstp,
                struct nfsd4_layoutcommit *lcp)
{
        return nfs_ok;
}

const struct nfsd4_layout_ops ff_layout_ops = {
        .notify_types           =
                        NOTIFY_DEVICEID4_DELETE | NOTIFY_DEVICEID4_CHANGE,
        .disable_recalls        = true,
        .proc_getdeviceinfo     = nfsd4_ff_proc_getdeviceinfo,
        .encode_getdeviceinfo   = nfsd4_ff_encode_getdeviceinfo,
        .proc_layoutget         = nfsd4_ff_proc_layoutget,
        .encode_layoutget       = nfsd4_ff_encode_layoutget,
        .proc_layoutcommit      = nfsd4_ff_proc_layoutcommit,
};