ceph-devel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	Oleksii Kurochko <olkuroch@cisco.com>,
	Sagi Grimberg <sagi@grimberg.me>,
	Mike Snitzer <snitzer@redhat.com>,
	Ilya Dryomov <idryomov@gmail.com>,
	Dongsheng Yang <dongsheng.yang@easystack.cn>,
	ceph-devel@vger.kernel.org, dm-devel@redhat.com,
	linux-block@vger.kernel.org, linux-nvme@lists.infradead.org
Subject: Re: [PATCH 1/4] block: add a hard-readonly flag to struct gendisk
Date: Wed, 02 Dec 2020 23:04:33 -0500	[thread overview]
Message-ID: <yq17dpza6nz.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <20201129181926.897775-2-hch@lst.de> (Christoph Hellwig's message of "Sun, 29 Nov 2020 19:19:23 +0100")


Hi Christoph!

>  - If BLKROSET is used to set a whole-disk device read-only, any
>    partitions will end up in a read-only state until the user
>    explicitly clears the flag.

This no longer appears to be the case with your tweak.

It's very common for database folks to twiddle the read-only state of
block devices and partitions. I know that our users will find it very
counter-intuitive that setting /dev/sda read-only won't prevent writes
to /dev/sda1.

>  int bdev_read_only(struct block_device *bdev)
>  {
>  	if (!bdev)
>  		return 0;
> -	return bdev->bd_read_only;
> +	return bdev->bd_read_only ||
> +		test_bit(GD_READ_ONLY, &bdev->bd_disk->state);
>  }

I suggest doing bd->bd_read_only || get_disk_ro(...) here. That does
take part0 into account.

>  static inline int get_disk_ro(struct gendisk *disk)
>  {
> -	return disk->part0->bd_read_only;
> +	return disk->part0->bd_read_only ||
> +		test_bit(GD_READ_ONLY, &disk->state);
>  }
>  
>  extern void disk_block_events(struct gendisk *disk);

-- 
Martin K. Petersen	Oracle Linux Engineering

  parent reply	other threads:[~2020-12-03  4:08 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-29 18:19 split hard read-only vs read-only policy v2 Christoph Hellwig
2020-11-29 18:19 ` [PATCH 1/4] block: add a hard-readonly flag to struct gendisk Christoph Hellwig
2020-11-30  1:23   ` Alex Elder
2020-11-30  7:55   ` Hannes Reinecke
2020-12-03  4:04   ` Martin K. Petersen [this message]
2020-12-03  8:53     ` Christoph Hellwig
2020-12-03 14:01       ` Martin K. Petersen
2020-11-29 18:19 ` [PATCH 2/4] rbd: remove the ->set_read_only method Christoph Hellwig
2020-11-30  7:56   ` Hannes Reinecke
2020-11-29 18:19 ` [PATCH 3/4] nvme: allow revalidate to set a namespace read-only Christoph Hellwig
2020-11-29 21:13   ` Chaitanya Kulkarni
2020-11-30  7:57   ` Hannes Reinecke
2020-11-29 18:19 ` [PATCH 4/4] dm: use bdev_read_only to check if a device is read-only Christoph Hellwig
2020-11-30  7:58   ` Hannes Reinecke

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=yq17dpza6nz.fsf@ca-mkp.ca.oracle.com \
    --to=martin.petersen@oracle.com \
    --cc=axboe@kernel.dk \
    --cc=ceph-devel@vger.kernel.org \
    --cc=dm-devel@redhat.com \
    --cc=dongsheng.yang@easystack.cn \
    --cc=hch@lst.de \
    --cc=idryomov@gmail.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-nvme@lists.infradead.org \
    --cc=olkuroch@cisco.com \
    --cc=sagi@grimberg.me \
    --cc=snitzer@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).