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Re: [PATCH 1/4] migration/savevm: respect qemu_fclose() error code in sa
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [PATCH 1/4] migration/savevm: respect qemu_fclose() error code in save_snapshot() |
Date: |
Mon, 15 Jun 2020 13:03:00 +0100 |
User-agent: |
Mutt/1.14.0 (2020-05-02) |
* Denis V. Lunev (den@openvz.org) wrote:
> qemu_fclose() could return error, f.e. if bdrv_co_flush() will return
> the error.
>
> This validation will become more important once we will start waiting of
> asynchronous IO operations, started from bdrv_write_vmstate(), which are
> coming soon.
>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Kevin Wolf <kwolf@redhat.com>
> CC: Max Reitz <mreitz@redhat.com>
> CC: Stefan Hajnoczi <stefanha@redhat.com>
> CC: Fam Zheng <fam@euphon.net>
> CC: Juan Quintela <quintela@redhat.com>
> CC: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> CC: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> CC: Denis Plotnikov <dplotnikov@virtuozzo.com>
We check the return value in very few other places; I think in the
migration case we do flushes and assume that if the flushes work we
were OK; then most of the closes happen on error paths or after points
we think we're done.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
> migration/savevm.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/migration/savevm.c b/migration/savevm.c
> index c00a6807d9..0ff5bb40ed 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -2628,7 +2628,7 @@ int save_snapshot(const char *name, Error **errp)
> {
> BlockDriverState *bs, *bs1;
> QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
> - int ret = -1;
> + int ret = -1, ret2;
> QEMUFile *f;
> int saved_vm_running;
> uint64_t vm_state_size;
> @@ -2712,10 +2712,14 @@ int save_snapshot(const char *name, Error **errp)
> }
> ret = qemu_savevm_state(f, errp);
> vm_state_size = qemu_ftell(f);
> - qemu_fclose(f);
> + ret2 = qemu_fclose(f);
> if (ret < 0) {
> goto the_end;
> }
> + if (ret2 < 0) {
> + ret = ret2;
> + goto the_end;
> + }
>
> /* The bdrv_all_create_snapshot() call that follows acquires the
> AioContext
> * for itself. BDRV_POLL_WHILE() does not support nested locking because
> --
> 2.17.1
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
- [PATCH v3 0/4] block: seriously improve savevm performance, Denis V. Lunev, 2020/06/11
- [PATCH 2/4] block/aio_task: allow start/wait task from any coroutine, Denis V. Lunev, 2020/06/11
- [PATCH 4/4] block/io: improve savevm performance, Denis V. Lunev, 2020/06/11
- [PATCH 1/4] migration/savevm: respect qemu_fclose() error code in save_snapshot(), Denis V. Lunev, 2020/06/11
- [PATCH 3/4] block, migration: add bdrv_flush_vmstate helper, Denis V. Lunev, 2020/06/11
- Re: [PATCH v3 0/4] block: seriously improve savevm performance, Dr. David Alan Gilbert, 2020/06/15