Kevin Wolf <kw...@redhat.com> writes:
> Am 16.10.2020 um 19:10 hat Vladimir Sementsov-Ogievskiy geschrieben:
>> Now bdrv_append returns status and we can drop all the local_err things
>> around it.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
>> Reviewed-by: Greg Kurz <gr...@kaod.org>
>> Reviewed-by: Alberto Garcia <be...@igalia.com>
>> ---
>> block.c | 5 +----
>> block/backup-top.c | 20 ++++++++------------
>> block/commit.c | 5 +----
>> block/mirror.c | 6 ++----
>> blockdev.c | 4 +---
>> tests/test-bdrv-graph-mod.c | 6 +++---
>> 6 files changed, 16 insertions(+), 30 deletions(-)
>>
>> diff --git a/block.c b/block.c
>> index b05fbff42d..7b6818c681 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -3161,7 +3161,6 @@ static BlockDriverState
>> *bdrv_append_temp_snapshot(BlockDriverState *bs,
>> int64_t total_size;
>> QemuOpts *opts = NULL;
>> BlockDriverState *bs_snapshot = NULL;
>> - Error *local_err = NULL;
>> int ret;
>>
>> /* if snapshot, we create a temporary backing file and open it
>> @@ -3208,9 +3207,7 @@ static BlockDriverState
>> *bdrv_append_temp_snapshot(BlockDriverState *bs,
>> * order to be able to return one, we have to increase
>> * bs_snapshot's refcount here */
>> bdrv_ref(bs_snapshot);
>> - bdrv_append(bs_snapshot, bs, &local_err);
>> - if (local_err) {
>> - error_propagate(errp, local_err);
>> + if (bdrv_append(bs_snapshot, bs, errp) < 0) {
>
> We generally avoid calling functions with side effects inside a
> comparison. Let's use the usual pattern:
>
> ret = bdrv_append(bs_snapshot, bs, errp);
> if (ret < 0) {
> ...
> }
I'd also advice against buring side effects too deep, but calling a
function in a failure-checking conditional is pretty benign. It's also
common:
$ git-grep 'if ([a-z].*) < 0) {'
coughs up several hundred instances.
That said, there is none in block.c. Local consistency matters.
[...]
