On 21.11.19 14:57, Sergio Lopez wrote: > bdrv_try_set_aio_context() requires that the old context is held, and > the new context is not held. Fix all the occurrences where it's not > done this way. > > Suggested-by: Max Reitz <mre...@redhat.com> > Signed-off-by: Sergio Lopez <s...@redhat.com> > --- > blockdev.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 58 insertions(+), 9 deletions(-)
I wonder whether we even need to set the target’s context, because I
suppose it should be done automatically when it is attached to the
backup job with bdrv_attach_child() in bdrv_backup_top_append(). *shrug*
> diff --git a/blockdev.c b/blockdev.c
> index 152a0f7454..b0647d8d33 100644
> --- a/blockdev.c
> +++ b/blockdev.c
[...]
> @@ -1868,6 +1880,20 @@ static void drive_backup_prepare(BlkActionState
> *common, Error **errp)
> goto out;
> }
>
> + /* Honor bdrv_try_set_aio_context() context acquisition requirements. */
> + old_context = bdrv_get_aio_context(target_bs);
> + aio_context_release(aio_context);
> + aio_context_acquire(old_context);
> +
> + ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
> + if (ret < 0) {
> + aio_context_release(old_context);
> + return;
> + }
> +
> + aio_context_release(old_context);
> + aio_context_acquire(aio_context);
Would it work to put the error block after these two calls so it can
just goto out again? (Which would help if someone were to e.g.
introduce a new resource that is to be freed behind the out label.)
> if (set_backing_hd) {
> bdrv_set_backing_hd(target_bs, source, &local_err);
> if (local_err) {
[...]
> @@ -4001,14 +4046,18 @@ void qmp_blockdev_mirror(bool has_job_id, const char
> *job_id,
>
> zero_target = (sync == MIRROR_SYNC_MODE_FULL);
>
> + /* Honor bdrv_try_set_aio_context() context acquisition requirements. */
> + old_context = bdrv_get_aio_context(target_bs);
> aio_context = bdrv_get_aio_context(bs);
> - aio_context_acquire(aio_context);
> + aio_context_acquire(old_context);
>
> ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
> if (ret < 0) {
> goto out;
> }
>
> + aio_context_acquire(aio_context);
> +
old_context is never released here.
Max
> blockdev_mirror_common(has_job_id ? job_id : NULL, bs, target_bs,
> has_replaces, replaces, sync, backing_mode,
> zero_target, has_speed, speed,
>
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