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From: Christoph Hellwig <hch@infradead.org>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	Zdenek Kabelac <zkabelac@redhat.com>,
	linux-block@vger.kernel.org, dm-devel@redhat.com
Subject: Re: [PATCH 4/4] brd: implement secure erase and write zeroes
Date: Tue, 20 Sep 2022 00:29:58 -0700	[thread overview]
Message-ID: <Yylr9g6B7Px6xBXb@infradead.org> (raw)
In-Reply-To: <alpine.LRH.2.02.2209160500190.543@file01.intranet.prod.int.rdu2.redhat.com>

On Fri, Sep 16, 2022 at 05:00:46AM -0400, Mikulas Patocka wrote:
> This patch implements REQ_OP_SECURE_ERASE and REQ_OP_WRITE_ZEROES on brd.
> Write zeroes will free the pages just like discard, but the difference is
> that it writes zeroes to the preceding and following page if the range is
> not aligned on page boundary. Secure erase is just like write zeroes,
> except that it clears the page content before freeing the page.

What is the use case of this?  And just a single overwrite is not what
storage standards would consider a secure erase, but then again we
don't really have any documentation or standards for the Linux OP,
which strongly suggests not actually implementing it for now.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, dm-devel@redhat.com,
	Zdenek Kabelac <zkabelac@redhat.com>
Subject: Re: [dm-devel] [PATCH 4/4] brd: implement secure erase and write zeroes
Date: Tue, 20 Sep 2022 00:29:58 -0700	[thread overview]
Message-ID: <Yylr9g6B7Px6xBXb@infradead.org> (raw)
In-Reply-To: <alpine.LRH.2.02.2209160500190.543@file01.intranet.prod.int.rdu2.redhat.com>

On Fri, Sep 16, 2022 at 05:00:46AM -0400, Mikulas Patocka wrote:
> This patch implements REQ_OP_SECURE_ERASE and REQ_OP_WRITE_ZEROES on brd.
> Write zeroes will free the pages just like discard, but the difference is
> that it writes zeroes to the preceding and following page if the range is
> not aligned on page boundary. Secure erase is just like write zeroes,
> except that it clears the page content before freeing the page.

What is the use case of this?  And just a single overwrite is not what
storage standards would consider a secure erase, but then again we
don't really have any documentation or standards for the Linux OP,
which strongly suggests not actually implementing it for now.

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


  reply	other threads:[~2022-09-20  7:30 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-16  8:58 [PATCH 0/4] brd: implement discard Mikulas Patocka
2022-09-16  8:58 ` [dm-devel] " Mikulas Patocka
2022-09-16  8:59 ` [PATCH 1/4] brd: make brd_insert_page return bool Mikulas Patocka
2022-09-16  8:59   ` [dm-devel] " Mikulas Patocka
2022-09-20  7:28   ` Christoph Hellwig
2022-09-20  7:28     ` [dm-devel] " Christoph Hellwig
2022-09-16  8:59 ` [PATCH 2/4] brd: extend the rcu regions to cover read and write Mikulas Patocka
2022-09-16  8:59   ` [dm-devel] " Mikulas Patocka
2022-09-20  7:38   ` Christoph Hellwig
2022-09-20  7:38     ` [dm-devel] " Christoph Hellwig
2022-09-16  9:00 ` [dm-devel] [PATCH 3/4] brd: enable discard Mikulas Patocka
2022-09-16  9:00   ` Mikulas Patocka
2022-09-20  7:39   ` [dm-devel] " Christoph Hellwig
2022-09-20  7:39     ` Christoph Hellwig
2022-09-20 17:47     ` [dm-devel] " Mikulas Patocka
2022-09-20 17:47       ` Mikulas Patocka
2022-09-16  9:00 ` [dm-devel] [PATCH 4/4] brd: implement secure erase and write zeroes Mikulas Patocka
2022-09-16  9:00   ` Mikulas Patocka
2022-09-20  7:29   ` Christoph Hellwig [this message]
2022-09-20  7:29     ` [dm-devel] " Christoph Hellwig
2022-09-20 17:46     ` Mikulas Patocka
2022-09-20 17:46       ` Mikulas Patocka

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