static void v9fs_read(void *opaque)

{

    int32_t fid;

    int64_t off;

    ssize_t err = 0;

    int32_t count = 0;

    size_t offset = 7;

    int32_t max_count;

    V9fsFidState *fidp;

    V9fsPDU *pdu = opaque;

    V9fsState *s = pdu->s;



    pdu_unmarshal(pdu, offset, "dqd", &fid, &off, &max_count);




    fidp = get_fid(pdu, fid);

    if (fidp == NULL) {

        err = -EINVAL;

        goto out_nofid;

    }

    if (fidp->fid_type == P9_FID_DIR) {



        if (off == 0) {

            v9fs_co_rewinddir(pdu, fidp);

        }

        count = v9fs_do_readdir_with_stat(pdu, fidp, max_count);

        if (count < 0) {

            err = count;

            goto out;

        }

        err = offset;

        err += pdu_marshal(pdu, offset, "d", count);

        err += count;

    } else if (fidp->fid_type == P9_FID_FILE) {

        int32_t cnt;

        int32_t len;

        struct iovec *sg;

        struct iovec iov[128]; 



        sg = iov;

        pdu_marshal(pdu, offset + 4, "v", sg, &cnt);

        sg = cap_sg(sg, max_count, &cnt);

        do {

            if (0) {

                print_sg(sg, cnt);

            }

            

            do {

                len = v9fs_co_preadv(pdu, fidp, sg, cnt, off);

                if (len >= 0) {

                    off   += len;

                    count += len;

                }

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

            if (len < 0) {

                

                err = len;

                goto out;

            }

            sg = adjust_sg(sg, len, &cnt);

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

        err = offset;

        err += pdu_marshal(pdu, offset, "d", count);

        err += count;

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

        err = v9fs_xattr_read(s, pdu, fidp, off, max_count);

    } else {

        err = -EINVAL;

    }

out:

    put_fid(pdu, fidp);

out_nofid:

    trace_v9fs_read_return(pdu->tag, pdu->id, count, err);

    complete_pdu(s, pdu, err);

}