Re: [dm-devel] [PATCH 29/44] block: remove the nr_sects field in struct hd_struct

From: Christoph Hellwig <hch@lst.de>
To: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>, Chao Yu <yuchao0@huawei.com>,
	Mike Snitzer <snitzer@redhat.com>,
	linux-mm@kvack.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jan Kara <jack@suse.com>, Josef Bacik <josef@toxicpanda.com>,
	Coly Li <colyli@suse.de>,
	linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	dm-devel@redhat.com, linux-mtd@lists.infradead.org,
	Johannes Thumshirn <johannes.thumshirn@wdc.com>,
	Tejun Heo <tj@kernel.org>,
	linux-bcache@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [dm-devel] [PATCH 29/44] block: remove the nr_sects field in struct hd_struct
Date: Fri, 27 Nov 2020 10:41:09 +0100	[thread overview]
Message-ID: <20201127094109.GB14976@lst.de> (raw)
In-Reply-To: <20201126180408.GB422@quack2.suse.cz>

On Thu, Nov 26, 2020 at 07:04:08PM +0100, Jan Kara wrote:
> On Thu 26-11-20 18:52:08, Christoph Hellwig wrote:
> > On Thu, Nov 26, 2020 at 05:50:36PM +0100, Jan Kara wrote:
> > > > +	if (size == capacity ||
> > > > +	    (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP)
> > > > +		return false;
> > > > +	pr_info("%s: detected capacity change from %lld to %lld\n",
> > > > +		disk->disk_name, size, capacity);
> > > > +	kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
> > > 
> > > I think we don't want to generate resize event for changes from / to 0...
> > 
> > Didn't you ask for that in the last round?
> 
> I've asked for the message - which you've added :). But the udev event was
> correct in the previous version IMHO...

Note that this version only prints if the gendisk is up.  So any initial
setup does not see a message.  I think that is a better indicator than
checking for 0.  Especially as say a remotely triggered change to 0
is an even worth printing, and except for DRBD all drivers did print
the message.

> 
> 								Honza
> -- 
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
---end quoted text---

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