Re: [PATCH 3/7] refs/files: add count field to ref_lock

> On Mon, Dec 9, 2024 at 12:11 PM Karthik Nayak <karthik.188@gmail.com> wrote:
>>
>> When refs are updated in the files-backend, a lock is obtained for the
>> corresponding file path. This is the case even for reflogs, i.e. a lock
>> is obtained on the reference path instead of the reflog path. This
>> works, since generally, reflogs are updated alongside the ref.
>>
>> The upcoming patches will add support for reflog updates in ref
>> transaction. This means, in a particular transaction we want to have ref
>> updates and reflog updates. For refs, in a given transaction there can
>> only be one update. But, we can theoretically have multiple reflog
>> updates in a given transaction.
>
> Nit: Giving an example might help understand where multiple reflog
> updates can happen in a given transaction. Alternatively pointing to
> an existing doc that contains such an example or explanations might
> help too.
>

>> @@ -2572,18 +2588,25 @@ static int lock_ref_for_update(struct files_ref_store *refs,
>>                         goto out;
>>         }
>>
>> -       ret = lock_raw_ref(refs, update->refname, mustexist,
>> -                          affected_refnames,
>> -                          &lock, &referent,
>> -                          &update->type, err);
>> -       if (ret) {
>> -               char *reason;
>> +       lock = strmap_get(&backend_data->ref_locks, update->refname);
>> +       if (lock) {
>> +               lock->count = lock->count + 1;
>
> Nit:
>               lock->count++;
>