static void coroutine_fn v9fs_open(void *opaque)
{
    int flags;
    int32_t fid;
    int32_t mode;
    V9fsQID qid;
    int iounit = 0;
    ssize_t err = 0;
    size_t offset = 7;
    struct stat stbuf;
    V9fsFidState *fidp;
    V9fsPDU *pdu = opaque;
    V9fsState *s = pdu->s;

    if (s->proto_version == V9FS_PROTO_2000L) {
        err = pdu_unmarshal(pdu, offset, "dd", &fid, &mode);
    } else {
        uint8_t modebyte;
        err = pdu_unmarshal(pdu, offset, "db", &fid, &modebyte);
        mode = modebyte;
    }
    if (err < 0) {
        goto out_nofid;
    }
    trace_v9fs_open(pdu->tag, pdu->id, fid, mode);

    fidp = get_fid(pdu, fid);
    if (fidp == NULL) {
        err = -ENOENT;
        goto out_nofid;
    }
    BUG_ON(fidp->fid_type != P9_FID_NONE);

    err = v9fs_co_lstat(pdu, &fidp->path, &stbuf);
    if (err < 0) {
        goto out;
    }
    stat_to_qid(&stbuf, &qid);
    if (S_ISDIR(stbuf.st_mode)) {
        err = v9fs_co_opendir(pdu, fidp);
        if (err < 0) {
            goto out;
        }
        fidp->fid_type = P9_FID_DIR;
        err = pdu_marshal(pdu, offset, "Qd", &qid, 0);
        if (err < 0) {
            goto out;
        }
        err += offset;
    } else {
        if (s->proto_version == V9FS_PROTO_2000L) {
            flags = get_dotl_openflags(s, mode);
        } else {
            flags = omode_to_uflags(mode);
        }
        if (is_ro_export(&s->ctx)) {
            if (mode & O_WRONLY || mode & O_RDWR ||
                mode & O_APPEND || mode & O_TRUNC) {
                err = -EROFS;
                goto out;
            }
        }
        err = v9fs_co_open(pdu, fidp, flags);
        if (err < 0) {
            goto out;
        }
        fidp->fid_type = P9_FID_FILE;
        fidp->open_flags = flags;
        if (flags & O_EXCL) {
            /*
             * We let the host file system do O_EXCL check
             * We should not reclaim such fd
             */
            fidp->flags |= FID_NON_RECLAIMABLE;
        }
        iounit = get_iounit(pdu, &fidp->path);
        err = pdu_marshal(pdu, offset, "Qd", &qid, iounit);
        if (err < 0) {
            goto out;
        }
        err += offset;
    }
    trace_v9fs_open_return(pdu->tag, pdu->id,
                           qid.type, qid.version, qid.path, iounit);
out:
    put_fid(pdu, fidp);
out_nofid:
    pdu_complete(pdu, err);
}

static void coroutine_fn v9fs_open(void *opaque)
{
    int flags;
    int32_t fid;
    int32_t mode;
    V9fsQID qid;
    int iounit = 0;
    ssize_t err = 0;
    size_t offset = 7;
    struct stat stbuf;
    V9fsFidState *fidp;
    V9fsPDU *pdu = opaque;
    V9fsState *s = pdu->s;

    if (s->proto_version == V9FS_PROTO_2000L) {
        err = pdu_unmarshal(pdu, offset, "dd", &fid, &mode);
    } else {
        uint8_t modebyte;
        err = pdu_unmarshal(pdu, offset, "db", &fid, &modebyte);
        mode = modebyte;
    }
    if (err < 0) {
        goto out_nofid;
    }
    trace_v9fs_open(pdu->tag, pdu->id, fid, mode);

    fidp = get_fid(pdu, fid);
    if (fidp == NULL) {
        err = -ENOENT;
        goto out_nofid;
    }
    BUG_ON(fidp->fid_type != P9_FID_NONE);

    err = v9fs_co_lstat(pdu, &fidp->path, &stbuf);
    if (err < 0) {
        goto out;
    }
    stat_to_qid(&stbuf, &qid);
    if (S_ISDIR(stbuf.st_mode)) {
        err = v9fs_co_opendir(pdu, fidp);
        if (err < 0) {
            goto out;
        }
        fidp->fid_type = P9_FID_DIR;
        err = pdu_marshal(pdu, offset, "Qd", &qid, 0);
        if (err < 0) {
            goto out;
        }
        err += offset;
    } else {
        if (s->proto_version == V9FS_PROTO_2000L) {
            flags = get_dotl_openflags(s, mode);
        } else {
            flags = omode_to_uflags(mode);
        }
        if (is_ro_export(&s->ctx)) {
            if (mode & O_WRONLY || mode & O_RDWR ||
                mode & O_APPEND || mode & O_TRUNC) {
                err = -EROFS;
                goto out;
            }
        }
        err = v9fs_co_open(pdu, fidp, flags);
        if (err < 0) {
            goto out;
        }
        fidp->fid_type = P9_FID_FILE;
        fidp->open_flags = flags;
        if (flags & O_EXCL) {
            /*
             * We let the host file system do O_EXCL check
             * We should not reclaim such fd
             */
            fidp->flags |= FID_NON_RECLAIMABLE;
        }
        iounit = get_iounit(pdu, &fidp->path);
        err = pdu_marshal(pdu, offset, "Qd", &qid, iounit);
        if (err < 0) {
            goto out;
        }
        err += offset;
    }
    trace_v9fs_open_return(pdu->tag, pdu->id,
                           qid.type, qid.version, qid.path, iounit);
out:
    put_fid(pdu, fidp);
out_nofid:
    pdu_complete(pdu, err);
}
