Re: [PATCH 1/4] qemu-file: Don't do IO after shutdown

[Dr. David Alan Gilbert]

* Juan Quintela (address@hidden) wrote:
> Be sure that we are not doing neither read/write after shutdown of the
> QEMUFile.
> 
> Signed-off-by: Juan Quintela <address@hidden>
> ---
>  migration/qemu-file.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/migration/qemu-file.c b/migration/qemu-file.c
> index 26fb25ddc1..1e5543a279 100644
> --- a/migration/qemu-file.c
> +++ b/migration/qemu-file.c
> @@ -53,6 +53,8 @@ struct QEMUFile {
>  
>      int last_error;
>      Error *last_error_obj;
> +    /* has the file has been shutdown */
> +    bool shutdown;
>  };
>  
>  /*
> @@ -61,6 +63,7 @@ struct QEMUFile {
>   */
>  int qemu_file_shutdown(QEMUFile *f)
>  {
> +    f->shutdown = true;
>      if (!f->ops->shut_down) {
>          return -ENOSYS;
>      }
> @@ -214,6 +217,9 @@ void qemu_fflush(QEMUFile *f)
>          return;
>      }
>  
> +    if (f->shutdown) {
> +        return;
> +    }

OK, I did wonder if you need to free the iovec.

>      if (f->iovcnt > 0) {
>          expect = iov_size(f->iov, f->iovcnt);
>          ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->pos,
> @@ -328,6 +334,10 @@ static ssize_t qemu_fill_buffer(QEMUFile *f)
>      f->buf_index = 0;
>      f->buf_size = pending;
>  
> +    if (f->shutdown) {
> +        return 0;
> +    }

I also wondered if perhaps an error would be reasonable here; but I'm
not sure what a read(2) does after a shutdown(2).

Still,


Reviewed-by: Dr. David Alan Gilbert <address@hidden>

>      len = f->ops->get_buffer(f->opaque, f->buf + pending, f->pos,
>                               IO_BUF_SIZE - pending, &local_error);
>      if (len > 0) {
> @@ -642,6 +652,9 @@ int64_t qemu_ftell(QEMUFile *f)
>  
>  int qemu_file_rate_limit(QEMUFile *f)
>  {
> +    if (f->shutdown) {
> +        return 1;
> +    }
>      if (qemu_file_get_error(f)) {
>          return 1;
>      }
> -- 
> 2.23.0
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK