static int64_t nfs_client_open(NFSClient *client, QDict *options,

                               int flags, int open_flags, Error **errp)

{

    int ret = -EINVAL;

    QemuOpts *opts = NULL;

    Error *local_err = NULL;

    struct stat st;

    char *file = NULL, *strp = NULL;



    opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);

    qemu_opts_absorb_qdict(opts, options, &local_err);

    if (local_err) {

        error_propagate(errp, local_err);

        ret = -EINVAL;

        goto fail;

    }



    client->path = g_strdup(qemu_opt_get(opts, "path"));

    if (!client->path) {

        ret = -EINVAL;

        error_setg(errp, "No path was specified");

        goto fail;

    }



    strp = strrchr(client->path, '/');

    if (strp == NULL) {

        error_setg(errp, "Invalid URL specified");

        goto fail;

    }

    file = g_strdup(strp);

    *strp = 0;



    /* Pop the config into our state object, Exit if invalid */

    client->server = nfs_config(options, errp);

    if (!client->server) {

        ret = -EINVAL;

        goto fail;

    }



    client->context = nfs_init_context();

    if (client->context == NULL) {

        error_setg(errp, "Failed to init NFS context");

        goto fail;

    }



    if (qemu_opt_get(opts, "user")) {

        client->uid = qemu_opt_get_number(opts, "user", 0);

        nfs_set_uid(client->context, client->uid);

    }



    if (qemu_opt_get(opts, "group")) {

        client->gid = qemu_opt_get_number(opts, "group", 0);

        nfs_set_gid(client->context, client->gid);

    }



    if (qemu_opt_get(opts, "tcp-syn-count")) {

        client->tcp_syncnt = qemu_opt_get_number(opts, "tcp-syn-count", 0);

        nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);

    }



#ifdef LIBNFS_FEATURE_READAHEAD

    if (qemu_opt_get(opts, "readahead-size")) {

        if (open_flags & BDRV_O_NOCACHE) {

            error_setg(errp, "Cannot enable NFS readahead "

                             "if cache.direct = on");

            goto fail;

        }

        client->readahead = qemu_opt_get_number(opts, "readahead-size", 0);

        if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {

            error_report("NFS Warning: Truncating NFS readahead "

                         "size to %d", QEMU_NFS_MAX_READAHEAD_SIZE);

            client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;

        }

        nfs_set_readahead(client->context, client->readahead);

#ifdef LIBNFS_FEATURE_PAGECACHE

        nfs_set_pagecache_ttl(client->context, 0);

#endif

        client->cache_used = true;

    }

#endif



#ifdef LIBNFS_FEATURE_PAGECACHE

    if (qemu_opt_get(opts, "page-cache-size")) {

        if (open_flags & BDRV_O_NOCACHE) {

            error_setg(errp, "Cannot enable NFS pagecache "

                             "if cache.direct = on");

            goto fail;

        }

        client->pagecache = qemu_opt_get_number(opts, "page-cache-size", 0);

        if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {

            error_report("NFS Warning: Truncating NFS pagecache "

                         "size to %d pages", QEMU_NFS_MAX_PAGECACHE_SIZE);

            client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;

        }

        nfs_set_pagecache(client->context, client->pagecache);

        nfs_set_pagecache_ttl(client->context, 0);

        client->cache_used = true;

    }

#endif



#ifdef LIBNFS_FEATURE_DEBUG

    if (qemu_opt_get(opts, "debug")) {

        client->debug = qemu_opt_get_number(opts, "debug", 0);

        /* limit the maximum debug level to avoid potential flooding

         * of our log files. */

        if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {

            error_report("NFS Warning: Limiting NFS debug level "

                         "to %d", QEMU_NFS_MAX_DEBUG_LEVEL);

            client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;

        }

        nfs_set_debug(client->context, client->debug);

    }

#endif



    ret = nfs_mount(client->context, client->server->host, client->path);

    if (ret < 0) {

        error_setg(errp, "Failed to mount nfs share: %s",

                   nfs_get_error(client->context));

        goto fail;

    }



    if (flags & O_CREAT) {

        ret = nfs_creat(client->context, file, 0600, &client->fh);

        if (ret < 0) {

            error_setg(errp, "Failed to create file: %s",

                       nfs_get_error(client->context));

            goto fail;

        }

    } else {

        ret = nfs_open(client->context, file, flags, &client->fh);

        if (ret < 0) {

            error_setg(errp, "Failed to open file : %s",

                       nfs_get_error(client->context));

            goto fail;

        }

    }



    ret = nfs_fstat(client->context, client->fh, &st);

    if (ret < 0) {

        error_setg(errp, "Failed to fstat file: %s",

                   nfs_get_error(client->context));

        goto fail;

    }



    ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);

    client->st_blocks = st.st_blocks;

    client->has_zero_init = S_ISREG(st.st_mode);

    *strp = '/';

    goto out;



fail:

    nfs_client_close(client);

out:

    qemu_opts_del(opts);

    g_free(file);

    return ret;

}
