From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Evan Green <evgreen@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>,
Bart Van Assche <bvanassche@acm.org>,
Gwendal Grignou <gwendal@chromium.org>,
Martin K Petersen <martin.petersen@oracle.com>,
Alexis Savery <asavery@chromium.org>,
Ming Lei <ming.lei@redhat.com>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] loop: Better discard support for block devices
Date: Wed, 13 Feb 2019 21:39:50 -0500 [thread overview]
Message-ID: <yq1d0nvqeix.fsf@oracle.com> (raw)
In-Reply-To: <20190207205730.199332-3-evgreen@chromium.org> (Evan Green's message of "Thu, 7 Feb 2019 12:57:29 -0800")
Evan,
> If the backing device for a loop device is a block device, then mirror
> the discard properties of the underlying block device into the loop
> device. While in there, differentiate between REQ_OP_DISCARD and
> REQ_OP_WRITE_ZEROES, which are different for block devices, but which
> the loop device had just been lumping together.
Bubbling up the queue limits from the backing device is fine. However,
I'm not sure why you are requiring a filesystem to be on a
discard-capable device for REQ_OP_DISCARD to have an effect? Punching a
hole in a file is semantically the same as discarding.
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2019-02-14 2:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-07 20:57 [PATCH v2 0/2] loop: Better discard for block devices Evan Green
2019-02-07 20:57 ` [PATCH v2 1/2] loop: Report EOPNOTSUPP properly Evan Green
2019-02-07 22:11 ` Bart Van Assche
2019-02-14 2:31 ` Martin K. Petersen
2019-02-26 19:27 ` Evan Green
2019-02-07 20:57 ` [PATCH v2 2/2] loop: Better discard support for block devices Evan Green
2019-02-14 2:39 ` Martin K. Petersen [this message]
2019-02-14 18:00 ` Evan Green
2019-02-26 17:23 ` Evan Green
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