static void coroutine_fn v9fs_write(void *opaque)

{

    ssize_t err;

    int32_t fid;

    uint64_t off;

    uint32_t count;

    int32_t len = 0;

    int32_t total = 0;

    size_t offset = 7;

    V9fsFidState *fidp;

    V9fsPDU *pdu = opaque;

    V9fsState *s = pdu->s;

    QEMUIOVector qiov_full;

    QEMUIOVector qiov;



    err = pdu_unmarshal(pdu, offset, "dqd", &fid, &off, &count);

    if (err < 0) {

        pdu_complete(pdu, err);

        return;

    }

    offset += err;

    v9fs_init_qiov_from_pdu(&qiov_full, pdu, offset, count, true);

    trace_v9fs_write(pdu->tag, pdu->id, fid, off, count, qiov_full.niov);



    fidp = get_fid(pdu, fid);

    if (fidp == NULL) {

        err = -EINVAL;

        goto out_nofid;

    }

    if (fidp->fid_type == P9_FID_FILE) {

        if (fidp->fs.fd == -1) {

            err = -EINVAL;

            goto out;

        }

    } else if (fidp->fid_type == P9_FID_XATTR) {

        /*

         * setxattr operation

         */

        err = v9fs_xattr_write(s, pdu, fidp, off, count,

                               qiov_full.iov, qiov_full.niov);

        goto out;

    } else {

        err = -EINVAL;

        goto out;

    }

    qemu_iovec_init(&qiov, qiov_full.niov);

    do {

        qemu_iovec_reset(&qiov);

        qemu_iovec_concat(&qiov, &qiov_full, total, qiov_full.size - total);

        if (0) {

            print_sg(qiov.iov, qiov.niov);

        }

        /* Loop in case of EINTR */

        do {

            len = v9fs_co_pwritev(pdu, fidp, qiov.iov, qiov.niov, off);

            if (len >= 0) {

                off   += len;

                total += len;

            }

        } while (len == -EINTR && !pdu->cancelled);

        if (len < 0) {

            /* IO error return the error */

            err = len;

            goto out_qiov;

        }

    } while (total < count && len > 0);



    offset = 7;

    err = pdu_marshal(pdu, offset, "d", total);

    if (err < 0) {

        goto out;

    }

    err += offset;

    trace_v9fs_write_return(pdu->tag, pdu->id, total, err);

out_qiov:

    qemu_iovec_destroy(&qiov);

out:

    put_fid(pdu, fidp);

out_nofid:

    qemu_iovec_destroy(&qiov_full);

    pdu_complete(pdu, err);

}
