Re: [PATCH v2 3/3] md: sync blockdev before stopping raid or setting readonly

[Li Nan]

在 2024/1/18 16:02, Mariusz Tkaczyk 写道:
> On Wed, 17 Jan 2024 17:37:07 +0800
> linan666@xxxxxxxxxxxxxxx wrote:
>
> > From: Li Nan <linan122@xxxxxxxxxx>
> >
> > Commit a05b7ea03d72 ("md: avoid crash when stopping md array races
> > with closing other open fds.") added sync_block before stopping raid and
> > setting readonly. Later in commit 260fa034ef7a ("md: avoid deadlock when
> > dirty buffers during md_stop.") it is moved to ioctl. array_state_store()
> > was ignored. Add sync blockdev to array_state_store() now.
> >
> > Signed-off-by: Li Nan <linan122@xxxxxxxxxx>

[...]

> > +
> > +	/* we will call set readonly or stop raid, sync blockdev */
> > +	if (st == clear || (mddev->pers && (st == readonly ||
> > +	    st == inactive || (st == read_auto && md_is_rdwr(mddev))))) {
> > +		err = mddev_sync_blockdev(mddev);
> > +		if (err)
> > +			return err;
> > +		clear_md_closing = true;
> > +	}
> > +
>
> Please reorganize it a little for readability:
> I think if no mddev->pers we don't need to consider sync_blockdev at all. If
> personality is there we can probably check for read-write. If it is not
> read-write then nothing to sync. What about that:
>
> if (mddev->pers && md_is_rdwr(mddev) &&
>      (st == clear || st == readonly || st == inactive || st == read_auto))
>
> Please note that I didn't test it so please let me know if you see issue in
> proposed logic.
> I think that we may be able to include it in "/* No lock dependent actions */"
> switch. Please consider it too:

Thanks for your review.
It is a really good idea. I will test and improve it.

> case clear:
> case readonly:
> case inactive:
> case read_auto:
>      if(!mddev->pers || !md_is_rdwr(mddev))
>            break;
>      err = mddev_sync_blockdev(mddev);
>      if (err)
>          return err;
>      clear_md_closing = true;
>      

--
Thanks,
Nan