From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Coly Li <colyli@suse.de>
Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
linux-raid@vger.kernel.org, nvdimm@lists.linux.dev,
antlists@youngman.org.uk, Dan Williams <dan.j.williams@intel.com>,
Hannes Reinecke <hare@suse.de>, Jens Axboe <axboe@kernel.dk>,
NeilBrown <neilb@suse.de>, Richard Fan <richard.fan@suse.com>,
Vishal L Verma <vishal.l.verma@intel.com>,
rafael@kernel.org
Subject: Re: Too large badblocks sysfs file (was: [PATCH v3 0/7] badblocks improvement for multiple bad block ranges)
Date: Thu, 23 Sep 2021 08:47:28 +0200 [thread overview]
Message-ID: <YUwjAJXjFR9tbJiQ@kroah.com> (raw)
In-Reply-To: <e227eb59-fcda-8f3e-d305-b4c21f0f2ef2@suse.de>
On Thu, Sep 23, 2021 at 02:14:12PM +0800, Coly Li wrote:
> On 9/23/21 2:08 PM, Greg Kroah-Hartman wrote:
> > On Thu, Sep 23, 2021 at 01:59:28PM +0800, Coly Li wrote:
> > > Hi all the kernel gurus, and folks in mailing lists,
> > >
> > > This is a question about exporting 4KB+ text information via sysfs
> > > interface. I need advice on how to handle the problem.
>
> Hi Greg,
>
> This is the code in mainline kernel for quite long time.
{sigh}
What tools rely on this? If none, just don't add new stuff to the file
and work to create a new api instead.
> > Please do not do that. Seriously, that is not what sysfs is for, and is
> > an abuse of it.
> >
> > sysfs is for "one value per file" and should never even get close to a
> > 4kb limit. If it does, you are doing something really really wrong and
> > should just remove that sysfs file from the system and redesign your
> > api.
>
> I understand this. And what I addressed is the problem I need to fix.
>
> The code is there for almost 10 years, I just find it during my work on bad
> blocks API fixing.
>
>
> > > Recently I work on the bad blocks API (block/badblocks.c) improvement, there
> > > is a sysfs file to export the bad block ranges for me raid. E.g for a md
> > > raid1 device, file
> > > /sys/block/md0/md/rd0/bad_blocks
> > > may contain the following text content,
> > > 64 32
> > > 128 8
> > Ick, again, that's not ok at all. sysfs files should never have to be
> > parsed like this.
>
> I cannot agree more with you. What I am asking for was ---- how to fix it ?
Best solution, come up with a new api.
Worst solution, you are stuck with the existing file and I can show you
the "way out" of dealing with files larger than 4kb in sysfs that a
number of other apis are being forced to do as they grow over time.
But ideally, just drop ths api and make a new one please.
thanks,
greg k-h
next prev parent reply other threads:[~2021-09-23 6:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-13 16:36 [PATCH v3 0/7] badblocks improvement for multiple bad block ranges Coly Li
2021-09-13 16:36 ` [PATCH v3 1/6] badblocks: add more helper structure and routines in badblocks.h Coly Li
2021-09-27 7:23 ` Geliang Tang
2021-09-27 8:23 ` Coly Li
2021-09-13 16:36 ` [PATCH v3 2/6] badblocks: add helper routines for badblock ranges handling Coly Li
2021-09-27 7:25 ` Geliang Tang
2021-09-27 8:17 ` Coly Li
2021-09-13 16:36 ` [PATCH v3 3/6] badblocks: improvement badblocks_set() for multiple " Coly Li
2021-09-27 7:30 ` Geliang Tang
2021-09-27 8:16 ` Coly Li
2021-09-13 16:36 ` [PATCH v3 4/6] badblocks: improve badblocks_clear() " Coly Li
2021-09-13 16:36 ` [PATCH v3 5/6] badblocks: improve badblocks_check() " Coly Li
2021-09-13 16:36 ` [PATCH v3 6/6] badblocks: switch to the improved badblock handling code Coly Li
2021-09-13 16:36 ` [PATCH] test: user space code to test badblocks APIs Coly Li
2021-09-23 5:59 ` Too large badblocks sysfs file (was: [PATCH v3 0/7] badblocks improvement for multiple bad block ranges) Coly Li
2021-09-23 6:08 ` Greg Kroah-Hartman
2021-09-23 6:14 ` Coly Li
2021-09-23 6:47 ` Greg Kroah-Hartman [this message]
2021-09-23 7:13 ` Coly Li
2021-09-23 9:40 ` Hannes Reinecke
2021-09-23 9:57 ` Greg Kroah-Hartman
2021-09-23 10:09 ` NeilBrown
2021-09-23 10:39 ` Greg Kroah-Hartman
2021-09-23 12:55 ` Coly Li
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