linux-ext4 - Re: [PATCH] fs/writeback: convert wbc_account_cgroup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ZvstH7UHpdnnDxW6@google.com>
Date: Mon, 30 Sep 2024 22:58:39 +0000
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: Matthew Wilcox <willy@...radead.org>
Cc: "Pankaj Raghav (Samsung)" <kernel@...kajraghav.com>,
	Theodore Ts'o <tytso@....edu>, Chao Yu <chao@...nel.org>,
	Jonathan Corbet <corbet@....net>,
	Josef Bacik <josef@...icpanda.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Michal Koutný <mkoutny@...e.com>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	"Darrick J . Wong" <djwong@...nel.org>,
	Zefan Li <lizefan.x@...edance.com>, Tejun Heo <tj@...nel.org>,
	akpm@...ux-foundation.org, Christian Brauner <brauner@...nel.org>,
	Andreas Dilger <adilger.kernel@...ger.ca>, Jan Kara <jack@...e.cz>,
	Chris Mason <clm@...com>, David Sterba <dsterba@...e.com>,
	cgroups@...r.kernel.org, linux-btrfs@...r.kernel.org,
	linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net,
	linux-fsdevel@...r.kernel.org, mcgrof@...nel.org,
	gost.dev@...sung.com, linux-doc@...r.kernel.org,
	linux-xfs@...r.kernel.org, Pankaj Raghav <p.raghav@...sung.com>
Subject: Re: [PATCH] fs/writeback: convert wbc_account_cgroup_owner to take a
 folio

On 09/26, Matthew Wilcox wrote:
> On Thu, Sep 26, 2024 at 04:01:21PM +0200, Pankaj Raghav (Samsung) wrote:
> > Convert wbc_account_cgroup_owner() to take a folio instead of a page,
> > and convert all callers to pass a folio directly except f2fs.
> > 
> > Convert the page to folio for all the callers from f2fs as they were the
> > only callers calling wbc_account_cgroup_owner() with a page. As f2fs is
> > already in the process of converting to folios, these call sites might
> > also soon be calling wbc_account_cgroup_owner() with a folio directly in
> > the future.
> 
> I was hoping for more from f2fs.  I still don't have an answer from them
> whether they're going to support large folios.  There's all kinds of
> crud already in these functions like:
> 
>         f2fs_set_bio_crypt_ctx(bio, fio->page->mapping->host,
>                         page_folio(fio->page)->index, fio, GFP_NOIO);
> 
> and this patch is making it worse, not better.  A series of patches
> which at least started to spread folios throughout f2fs would be better.
> I think that struct f2fs_io_info should have its page converted to
> a folio, for example.  Although maybe not; perhaps this structure can
> carry data which doesn't belong to a folio that came from the page cache.
> It's very hard to tell because f2fs is so mind-numbingly complex and
> riddled with stupid abstraction layers.

Hah, I don't think it's too complex at all tho, there's a somewhat complexity to
support file-based encryption, compression, and fsverity, which are useful
for Android users. Well, I don't see any strong needs to support large folio,
but some requests exist which was why we had to do some conversion.

> 
> But I don't know what the f2fs maintainers have planned.  And they won't
> tell me despite many times of asking.