>>> On 8/22/16, 10:32 PM, "Shaohua Li" <shli@xxxxxxxxxx> wrote:
>>
> > +enum r5c_cache_mode {
> > + R5C_MODE_NO_CACHE = 0,
> > + R5C_MODE_WRITE_THROUGH = 1,
> > + R5C_MODE_WRITE_BACK = 2,
> > + R5C_MODE_BROKEN_CACHE = 3,
> The idea of setting different modes makes sense.
> But this is a little confusing. The first three are modes, the last one is status.
> We can't set BROKEN_CACHE mode, right?
How about we name it as r5c_cache_state? Splitting it into two entries
seems an overkill to me.
>> + spin_lock_irq(&conf->device_lock);
> > + if (log)
> > + conf->log->cache_mode = val;
> > + if (val == R5C_MODE_NO_CACHE) {
> > + clear_bit(MD_HAS_JOURNAL, &mddev->flags);
> > + set_bit(MD_UPDATE_SB_FLAGS, &mddev->flags);
> If the journal disk is Faulty and we clear HAS_JOURNAL, what's role of journal
> disk?
The on disk role is faulty (0xffff). The in memory data structure will show both
Faulty and Journal. It works in my test (create -> fail journal -> remove journal ->
write -> stop -> assemble).
> This sounds incomplete. If we assemble the array and journal disk is missing,
> can we set the mode to NO_CACHE and allow the array writeable?
Do you mean setting to NO_CACHE automatically? I think it is not safe, as we
may assemble and run the array accidentally without the journal. If the array
is set to NO_CACHE, we will lost pending data on the journal.
>> +extern ssize_t r5c_show_cache_mode(struct mddev *mddev, char *page);
> > +extern ssize_t
> > +r5c_store_cache_mode(struct mddev *mddev, const char *page, size_t len);
>
> Instead of export two functions, you can move r5c_cache_mode sysfs entry to raid5-cache.c
> and export it.
Will fix it in the next version.
Thanks,
Song
��.n��������+%������w��{.n�����{����w��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
