From: Christoph Hellwig <hch@infradead.org>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Kirill Tkhai <ktkhai@virtuozzo.com>,
axboe@kernel.dk, bob.liu@oracle.com, agk@redhat.com,
snitzer@redhat.com, dm-devel@redhat.com, song@kernel.org,
tytso@mit.edu, adilger.kernel@dilger.ca,
Chaitanya.Kulkarni@wdc.com, ming.lei@redhat.com, osandov@fb.com,
jthumshirn@suse.de, minwoo.im.dev@gmail.com,
damien.lemoal@wdc.com, andrea.parri@amarulasolutions.com,
hare@suse.com, tj@kernel.org, ajay.joshi@wdc.com,
sagi@grimberg.me, dsterba@suse.com, bvanassche@acm.org,
dhowells@redhat.com, asml.silence@gmail.com,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 0/6] block: Introduce REQ_ALLOCATE flag for REQ_OP_WRITE_ZEROES
Date: Thu, 26 Mar 2020 02:29:35 -0700 [thread overview]
Message-ID: <20200326092935.GA6478@infradead.org> (raw)
In-Reply-To: <yq1d090jqlm.fsf@oracle.com>
On Wed, Mar 25, 2020 at 01:23:33PM -0400, Martin K. Petersen wrote:
>
> Christoph,
>
> > I am very much against that for the following reason:
> >
> > - the current REQ_OP_DISCARD is purely a hint, and implementations can
> > (and do) choose to ignore it
> >
> > - REQ_OP_WRITE_ZEROES is an actual data integrity operation with
> > everything that entails
>
> If you want to keep emphasis on the "integrity operation" instead of the
> provisioning aspect, would you expect REQ_ALLOCATE (which may or may not
> zero blocks) to be considered a deterministic operation or a
> non-deterministic one? Should this depend on whether the device
> guarantees zeroing when provisioning blocks or not?
That's why I don't like the whole flags game very much. I'd rather
have REQ_OP_WRITE_ZEROES as the integrity operation that gurantees
zeroing, and a REQ_ALLOCATE that doesn't guarantee zeroing, just some
deterministic state of the blocks.
next prev parent reply other threads:[~2020-03-26 9:29 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-13 7:39 [PATCH v7 0/6] block: Introduce REQ_ALLOCATE flag for REQ_OP_WRITE_ZEROES Kirill Tkhai
2020-02-13 7:39 ` [PATCH v7 1/6] block: Add @flags argument to bdev_write_zeroes_sectors() Kirill Tkhai
2020-02-13 7:39 ` [PATCH v7 2/6] block: Pass op_flags into blk_queue_get_max_sectors() Kirill Tkhai
2020-02-13 7:39 ` [PATCH v7 3/6] block: Introduce blk_queue_get_max_write_zeroes_sectors() Kirill Tkhai
2020-02-13 7:39 ` [PATCH v7 4/6] block: Add support for REQ_ALLOCATE flag Kirill Tkhai
2020-02-13 7:39 ` [PATCH v7 5/6] block: Add blk_queue_max_allocate_sectors() Kirill Tkhai
2020-02-13 7:39 ` [PATCH v7 6/6] loop: Add support for REQ_ALLOCATE Kirill Tkhai
2020-02-13 18:11 ` Darrick J. Wong
2020-02-13 20:07 ` Kirill Tkhai
2020-02-13 7:55 ` [PATCH v7 0/6] block: Introduce REQ_ALLOCATE flag for REQ_OP_WRITE_ZEROES Kirill Tkhai
2020-03-06 9:11 ` Kirill Tkhai
2020-03-13 13:08 ` Kirill Tkhai
2020-03-19 10:28 ` Christoph Hellwig
2020-03-19 10:42 ` Kirill Tkhai
2020-03-19 13:03 ` Martin K. Petersen
2020-03-25 16:26 ` Darrick J. Wong
2020-03-25 16:32 ` Christoph Hellwig
2020-03-25 17:23 ` Martin K. Petersen
2020-03-26 9:29 ` Christoph Hellwig [this message]
2020-03-26 14:34 ` Martin K. Petersen
2020-03-26 14:45 ` Christoph Hellwig
2020-03-26 16:48 ` Chaitanya Kulkarni
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