From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>,
axboe@kernel.dk, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org,
tytso@mit.edu, adilger.kernel@dilger.ca, 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, chaitanya.kulkarni@wdc.com,
bvanassche@acm.org, dhowells@redhat.com, asml.silence@gmail.com
Subject: Re: [PATCH RFC 1/3] block: Add support for REQ_OP_ASSIGN_RANGE operation
Date: Thu, 19 Dec 2019 17:53:39 -0800 [thread overview]
Message-ID: <20191220015338.GB7473@magnolia> (raw)
In-Reply-To: <yq1a77oc56s.fsf@oracle.com>
On Thu, Dec 19, 2019 at 05:37:47PM -0500, Martin K. Petersen wrote:
>
> Kirill,
>
> > Hm. BLKDEV_ZERO_NOUNMAP is used in __blkdev_issue_write_zeroes() only.
> > So, do I understand right that we should the below two?:
> >
> > 1) Introduce a new flag BLKDEV_ZERO_ALLOCATE for
> > blkdev_issue_write_zeroes().
>
> > 2) Introduce a new flag REQ_NOZERO in enum req_opf.
>
> Something like that. If zeroing is a problem for you.
>
> Right now we offer the following semantics:
>
> Deallocate, no zeroing (discard)
>
> Optionally deallocate, zeroing (zeroout)
>
> Allocate, zeroing (zeroout + NOUNMAP)
>
> Some devices also implement a fourth option which would be:
>
> Anchor: Allocate, no zeroing
What happens if you anchor and then try to read the results? IO error?
(Yeah, I'm being lazy and not digging through SBC-3, sorry...)
--D
> > Won't this confuse a reader that we have blkdev_issue_write_zeroes(),
> > which does not write zeroes sometimes? Maybe we should rename
> > blkdev_issue_write_zeroes() in some more generic name?
>
> Maybe. The naming is what it is for hysterical raisins and reflects how
> things are implemented in the storage protocols. I wouldn't worry too
> much about that. We can rename things if need be but we shouldn't plumb
> an essentially identical operation through the block stack just to
> expose a different name at the top.
>
> --
> Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2019-12-20 1:55 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-10 16:56 [PATCH RFC 0/3] block,ext4: Introduce REQ_OP_ASSIGN_RANGE to reflect extents allocation in block device internals Kirill Tkhai
2019-12-10 16:56 ` [PATCH RFC 1/3] block: Add support for REQ_OP_ASSIGN_RANGE operation Kirill Tkhai
2019-12-19 3:03 ` Martin K. Petersen
2019-12-19 11:07 ` Kirill Tkhai
2019-12-19 22:03 ` Chaitanya Kulkarni
2019-12-19 22:37 ` Martin K. Petersen
2019-12-20 1:53 ` Darrick J. Wong [this message]
2019-12-20 2:22 ` Martin K. Petersen
2019-12-20 11:55 ` Kirill Tkhai
2019-12-21 18:54 ` Martin K. Petersen
2019-12-23 8:51 ` Kirill Tkhai
2020-01-07 3:24 ` Martin K. Petersen
2020-01-07 13:59 ` Kirill Tkhai
2020-01-08 2:49 ` Martin K. Petersen
2020-01-09 9:43 ` Kirill Tkhai
2019-12-10 16:56 ` [PATCH RFC 2/3] loop: Forward REQ_OP_ASSIGN_RANGE into fallocate(0) Kirill Tkhai
2019-12-10 16:56 ` [PATCH RFC 3/3] ext4: Notify block device about fallocate(0)-assigned blocks Kirill Tkhai
2019-12-11 1:02 ` kbuild test robot
2019-12-11 12:55 ` [PATCH RFC v2 " Kirill Tkhai
2019-12-15 15:35 ` [PATCH RFC " kbuild test robot
2019-12-11 7:42 ` [PATCH RFC 0/3] block,ext4: Introduce REQ_OP_ASSIGN_RANGE to reflect extents allocation in block device internals Chaitanya Kulkarni
2019-12-11 8:50 ` Kirill Tkhai
2019-12-17 14:16 ` Kirill Tkhai
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