From mboxrd@z Thu Jan 1 00:00:00 1970 From: Edward Shishkin Subject: Re: [patch] reiser4: port for Linux-4.1 Date: Sun, 05 Jul 2015 21:46:39 +0800 Message-ID: <5599353F.3090005@gmail.com> References: <558D5C72.2040203@gmail.com> <55918654.80703@gmail.com> <1435648387.15634.3.camel@gmail.com> <559245B3.1020804@gmail.com> <1435651611.15634.12.camel@gmail.com> <55925A3C.6000604@gmail.com> <1435793708.3758.14.camel@gmail.com> <559790E1.2020009@gmail.com> <1436032389.25552.6.camel@gmail.com> <559826F3.9010201@gmail.com> <1436101712.6440.3.camel@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; bh=16Etnbx8UHsuLOeFIiMEhMS65rpx6OYAUf8NyQQp+Ws=; b=RVGTXzEa0FzgYw8oU3jrze6frfhcrwQ2QWSGv+OhyRjpdUIEJSpephHqUiV2FriDOD ttEDkQw1mW/BRYh8xPzHsySvvC0xqvb8/b9q3ykr3LRZA9k1wZzUAT9Dkjzf1UjoRFtp qsaoGPDp919udSoXZ/Wpz3Gs0wZ05aRASlDMpYB8uZTtCO0Kuvcowqh3CwHY8HK+/n61 oofUx5InX+itP9XOgfQfsbLwbMnUvnr5Mj3Ly2RE8ApMluMmn8/NDIslCCAN8LeuiTgu aDXeEtBl31ktChn63PxCjlM0koegnDEkucDYGSnEaVzhASQ97hGAJCnjFS0UUiQtViLH a5og== In-Reply-To: <1436101712.6440.3.camel@gmail.com> Sender: reiserfs-devel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Ivan Shapovalov , ReiserFS development mailing list On 07/05/2015 09:08 PM, Ivan Shapovalov wrote: > On 2015-07-05 at 02:33 +0800, Edward Shishkin wrote: >> On 07/05/2015 01:53 AM, Ivan Shapovalov wrote: >>> On 2015-07-04 at 15:53 +0800, Edward Shishkin wrote: >>>> [...] >>>> And how to test directly at mount time? >>> Something along the lines of >>> - allocate 1 MiB of contiguous space >>> - fill it with non-zeros >>> - for N = 1, 2, 4, ...: >>> - discard N sectors from the contiguous space >>> - check if anything in the discarded space became zero-filled >>> - if it did, infer alignnment from the first zero-filled block, >>> infer granularity from the zero-filled region size. >> >> mkfs seems to be more suitable for this funny business > Yeah, sure. So... new superblock format with two extra fields? The change will be forward and backward compatible, so there is no need in a new format. Just add two new fields to the superblock40. Also people will want to "mount -o discard" when discard parameters are not known. In this case I think to provide them discard_extents(). which is currently merged. Otherwise use discard_precise_extents(). Thanks, Edward. > >> >>>> It seems that nobody cares about it.. >>> It's just ATA interface does not provide necessary data. >> >> OK, so our precise discard extension is waiting for the >> best times.. > I hope we'll be able to merge it eventually (esp. the final patch which > accounts for non-idempotence of check-and-allocate-blocks). > > Thanks,