17.10.2019 15:04, Peter Maydell wrote:
> On Thu, 10 Oct 2019 at 12:44, Max Reitz <[email protected]> wrote:
>>
>> From: Vladimir Sementsov-Ogievskiy <[email protected]>
>>
>> Drop write notifiers and use filter node instead.
>
> Hi; after this change Coverity complains about dead code in
> backup_job_create() (CID 1406402):
Oops, I'm sorry. Will send a patch soon.
>
>> @@ -382,6 +353,8 @@ BlockJob *backup_job_create(const char *job_id,
>> BlockDriverState *bs,
>> BackupBlockJob *job = NULL;
>> int64_t cluster_size;
>> BdrvRequestFlags write_flags;
>> + BlockDriverState *backup_top = NULL;
>> + BlockCopyState *bcs = NULL;
>>
>> assert(bs);
>> assert(target);
>> @@ -463,33 +436,35 @@ BlockJob *backup_job_create(const char *job_id,
>> BlockDriverState *bs,
>> write_flags = (bdrv_chain_contains(target, bs) ? BDRV_REQ_SERIALISING
>> : 0) |
>> (compress ? BDRV_REQ_WRITE_COMPRESSED : 0),
>>
>> + backup_top = bdrv_backup_top_append(bs, target, filter_node_name,
>> + cluster_size, write_flags, &bcs,
>> errp);
>> + if (!backup_top) {
>> + goto error;
>> + }
>> +
>> /* job->len is fixed, so we can't allow resize */
>> - job = block_job_create(job_id, &backup_job_driver, txn, bs, 0,
>> BLK_PERM_ALL,
>> + job = block_job_create(job_id, &backup_job_driver, txn, backup_top,
>> + 0, BLK_PERM_ALL,
>> speed, creation_flags, cb, opaque, errp);
>> if (!job) {
>> goto error;
>> }
>>
>> + job->backup_top = backup_top;
>> job->source_bs = bs;
>> job->on_source_error = on_source_error;
>> job->on_target_error = on_target_error;
>> job->sync_mode = sync_mode;
>> job->sync_bitmap = sync_bitmap;
>> job->bitmap_mode = bitmap_mode;
>> -
>> - job->bcs = block_copy_state_new(bs, target, cluster_size, write_flags,
>> - errp);
>> - if (!job->bcs) {
>> - goto error;
>> - }
>> -
>
> This code deletion has removed the only code path that can
> reach the 'error' label after the successful creation of the job...
>
>> + job->bcs = bcs;
>> job->cluster_size = cluster_size;
>> job->len = len;
>>
>> - block_copy_set_callbacks(job->bcs, backup_progress_bytes_callback,
>> + block_copy_set_callbacks(bcs, backup_progress_bytes_callback,
>> backup_progress_reset_callback, job);
>>
>> - /* Required permissions are already taken by block-copy-state target */
>> + /* Required permissions are already taken by backup-top target */
>> block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
>> &error_abort);
>>
>> @@ -502,6 +477,8 @@ BlockJob *backup_job_create(const char *job_id,
>> BlockDriverState *bs,
>> if (job) {
>> backup_clean(&job->common.job);
>> job_early_fail(&job->common.job);
>
> ...so down here in the 'error:' code the "if (job)" condition
> can never pass, and the code in this part of the if statement
> is dead.
>
>> + } else if (backup_top) {
>> + bdrv_backup_top_drop(backup_top);
>> }
>>
>> return NULL;
>> {"return": {}}
>
> thanks
> -- PMM
>
--
Best regards,
Vladimir
