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From: Christoph Hellwig <hch@lst.de>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	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: Thu, 3 Dec 2020 09:53:39 +0100	[thread overview]
Message-ID: <20201203085339.GA17110@lst.de> (raw)
In-Reply-To: <yq17dpza6nz.fsf@ca-mkp.ca.oracle.com>

On Wed, Dec 02, 2020 at 11:04:33PM -0500, Martin K. Petersen wrote:
> 
> 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.

True.

> 
> 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.

What I'm worried about it is that this would be a huge change from the
historic behavior.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>, Sagi Grimberg <sagi@grimberg.me>,
	Mike Snitzer <snitzer@redhat.com>,
	Oleksii Kurochko <olkuroch@cisco.com>,
	ceph-devel@vger.kernel.org,
	Dongsheng Yang <dongsheng.yang@easystack.cn>,
	linux-block@vger.kernel.org, dm-devel@redhat.com,
	linux-nvme@lists.infradead.org, Ilya Dryomov <idryomov@gmail.com>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 1/4] block: add a hard-readonly flag to struct gendisk
Date: Thu, 3 Dec 2020 09:53:39 +0100	[thread overview]
Message-ID: <20201203085339.GA17110@lst.de> (raw)
In-Reply-To: <yq17dpza6nz.fsf@ca-mkp.ca.oracle.com>

On Wed, Dec 02, 2020 at 11:04:33PM -0500, Martin K. Petersen wrote:
> 
> 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.

True.

> 
> 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.

What I'm worried about it is that this would be a huge change from the
historic behavior.

_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>, Sagi Grimberg <sagi@grimberg.me>,
	Mike Snitzer <snitzer@redhat.com>,
	Oleksii Kurochko <olkuroch@cisco.com>,
	ceph-devel@vger.kernel.org,
	Dongsheng Yang <dongsheng.yang@easystack.cn>,
	linux-block@vger.kernel.org, dm-devel@redhat.com,
	linux-nvme@lists.infradead.org, Ilya Dryomov <idryomov@gmail.com>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [dm-devel] [PATCH 1/4] block: add a hard-readonly flag to struct gendisk
Date: Thu, 3 Dec 2020 09:53:39 +0100	[thread overview]
Message-ID: <20201203085339.GA17110@lst.de> (raw)
In-Reply-To: <yq17dpza6nz.fsf@ca-mkp.ca.oracle.com>

On Wed, Dec 02, 2020 at 11:04:33PM -0500, Martin K. Petersen wrote:
> 
> 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.

True.

> 
> 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.

What I'm worried about it is that this would be a huge change from the
historic behavior.

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel


  reply	other threads:[~2020-12-03  8:54 UTC|newest]

Thread overview: 42+ 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 ` [dm-devel] " Christoph Hellwig
2020-11-29 18:19 ` Christoph Hellwig
2020-11-29 18:19 ` [PATCH 1/4] block: add a hard-readonly flag to struct gendisk Christoph Hellwig
2020-11-29 18:19   ` [dm-devel] " Christoph Hellwig
2020-11-29 18:19   ` Christoph Hellwig
2020-11-30  1:23   ` Alex Elder
2020-11-30  1:23     ` [dm-devel] " Alex Elder
2020-11-30  1:23     ` Alex Elder
2020-11-30  7:55   ` Hannes Reinecke
2020-11-30  7:55     ` [dm-devel] " Hannes Reinecke
2020-11-30  7:55     ` Hannes Reinecke
2020-12-03  4:04   ` Martin K. Petersen
2020-12-03  4:04     ` [dm-devel] " Martin K. Petersen
2020-12-03  4:04     ` Martin K. Petersen
2020-12-03  8:53     ` Christoph Hellwig [this message]
2020-12-03  8:53       ` [dm-devel] " Christoph Hellwig
2020-12-03  8:53       ` Christoph Hellwig
2020-12-03 14:01       ` Martin K. Petersen
2020-12-03 14:01         ` [dm-devel] " Martin K. Petersen
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
2020-11-29 18:19   ` [dm-devel] " Christoph Hellwig
2020-11-29 18:19   ` Christoph Hellwig
2020-11-30  7:56   ` Hannes Reinecke
2020-11-30  7:56     ` [dm-devel] " Hannes Reinecke
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 18:19   ` [dm-devel] " Christoph Hellwig
2020-11-29 18:19   ` Christoph Hellwig
2020-11-29 21:13   ` Chaitanya Kulkarni
2020-11-29 21:13     ` [dm-devel] " Chaitanya Kulkarni
2020-11-29 21:13     ` Chaitanya Kulkarni
2020-11-30  7:57   ` Hannes Reinecke
2020-11-30  7:57     ` [dm-devel] " Hannes Reinecke
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
2020-11-29 18:19   ` [dm-devel] " Christoph Hellwig
2020-11-29 18:19   ` Christoph Hellwig
2020-11-30  7:58   ` Hannes Reinecke
2020-11-30  7:58     ` [dm-devel] " Hannes Reinecke
2020-11-30  7:58     ` Hannes Reinecke

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