// SPDX-License-Identifier: GPL-2.0
/*
 * This file contains all the stubs needed when communicating with lockd.
 * This level of indirection is necessary so we can run nfsd+lockd without
 * requiring the nfs client to be compiled in/loaded, and vice versa.
 *
 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/file.h>
#include <linux/lockd/bind.h>
#include "nfsd.h"
#include "vfs.h"

#define NFSDDBG_FACILITY                NFSDDBG_LOCKD

#ifdef CONFIG_LOCKD_V4
#define nlm_stale_fh    nlm4_stale_fh
#define nlm_failed      nlm4_failed
#else
#define nlm_stale_fh    nlm_lck_denied_nolocks
#define nlm_failed      nlm_lck_denied_nolocks
#endif
/*
 * Note: we hold the dentry use count while the file is open.
 */
static __be32
nlm_fopen(struct svc_rqst *rqstp, struct nfs_fh *f, struct file **filp,
                int mode)
{
        __be32          nfserr;
        int             access;
        struct svc_fh   fh;

        /* must initialize before using! but maxsize doesn't matter */
        fh_init(&fh,0);
        fh.fh_handle.fh_size = f->size;
        memcpy(&fh.fh_handle.fh_raw, f->data, f->size);
        fh.fh_export = NULL;

        /*
         * Allow BYPASS_GSS as some client implementations use AUTH_SYS
         * for NLM even when GSS is used for NFS.
         * Allow OWNER_OVERRIDE as permission might have been changed
         * after the file was opened.
         * Pass MAY_NLM so that authentication can be completely bypassed
         * if NFSEXP_NOAUTHNLM is set.  Some older clients use AUTH_NULL
         * for NLM requests.
         */
        access = (mode == O_WRONLY) ? NFSD_MAY_WRITE : NFSD_MAY_READ;
        access |= NFSD_MAY_NLM | NFSD_MAY_OWNER_OVERRIDE | NFSD_MAY_BYPASS_GSS;
        nfserr = nfsd_open(rqstp, &fh, S_IFREG, access, filp);
        fh_put(&fh);
        /* We return nlm error codes as nlm doesn't know
         * about nfsd, but nfsd does know about nlm..
         */
        switch (nfserr) {
        case nfs_ok:
                return 0;
        case nfserr_jukebox:
                /* this error can indicate a presence of a conflicting
                 * delegation to an NLM lock request. Options are:
                 * (1) For now, drop this request and make the client
                 * retry. When delegation is returned, client's lock retry
                 * will complete.
                 * (2) NLM4_DENIED as per "spec" signals to the client
                 * that the lock is unavailable now but client can retry.
                 * Linux client implementation does not. It treats
                 * NLM4_DENIED same as NLM4_FAILED and errors the request.
                 * (3) For the future, treat this as blocked lock and try
                 * to callback when the delegation is returned but might
                 * not have a proper lock request to block on.
                 */
                return nlm_drop_reply;
        case nfserr_stale:
                return nlm_stale_fh;
        default:
                return nlm_failed;
        }
}

static void
nlm_fclose(struct file *filp)
{
        fput(filp);
}

static const struct nlmsvc_binding nfsd_nlm_ops = {
        .fopen          = nlm_fopen,            /* open file for locking */
        .fclose         = nlm_fclose,           /* close file */
};

void
nfsd_lockd_init(void)
{
        dprintk("nfsd: initializing lockd\n");
        nlmsvc_ops = &nfsd_nlm_ops;
}

void
nfsd_lockd_shutdown(void)
{
        nlmsvc_ops = NULL;
}