what does bch_journal_meta do?

[Pony Cheng <ponycheng0@xxxxxxxxx>]

Hi all,

When I read the bcache source code, I confused about function
bch_journal_meta. What does this function do? It calls bch_journal and
when ret is not null, will increase ret's value, why decrease ret's
value outsize?

atomic_t *bch_journal(struct cache_set *c,
                      struct keylist *keys,
                      struct closure *parent)
{

...

ret = &fifo_back(&c->journal.pin);

atomic_inc(ret);

...

return ret;

}


void bch_journal_meta(struct cache_set *c, struct closure *cl)
{
        struct keylist keys;
        atomic_t *ref;
        bch_keylist_init(&keys);
        ref = bch_journal(c, &keys, cl);
        if (ref)
                atomic_dec_bug(ref);
}