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Re: [PATCH 1/4] qemu-file: Don't do IO after shutdown
From: |
Juan Quintela |
Subject: |
Re: [PATCH 1/4] qemu-file: Don't do IO after shutdown |
Date: |
Wed, 18 Dec 2019 15:35:17 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) |
"Dr. David Alan Gilbert" <address@hidden> wrote:
> * 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.
I will think about this one.
>> 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).
A fast google shows that it is .... implementation dependant. And
worse, only really works for sockets.
> Still,
>
>
> Reviewed-by: Dr. David Alan Gilbert <address@hidden>
Thanks.