linux-ext4 - Re: [PATCH v3 4/4] ext4: support uncached buffered I/O

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] [day] [month] [year] [list]

Message-ID: <aGZtcSIryAj4zJtF@casper.infradead.org>
Date: Thu, 3 Jul 2025 12:45:53 +0100
From: Matthew Wilcox <willy@...radead.org>
To: "hch@...radead.org" <hch@...radead.org>
Cc: 陈涛涛 Taotao Chen <chentaotao@...iglobal.com>,
	"tytso@....edu" <tytso@....edu>,
	"adilger.kernel@...ger.ca" <adilger.kernel@...ger.ca>,
	"brauner@...nel.org" <brauner@...nel.org>,
	"jani.nikula@...ux.intel.com" <jani.nikula@...ux.intel.com>,
	"rodrigo.vivi@...el.com" <rodrigo.vivi@...el.com>,
	"tursulin@...ulin.net" <tursulin@...ulin.net>,
	"airlied@...il.com" <airlied@...il.com>,
	"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
	"linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
	"intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"chentao325@...com" <chentao325@...com>,
	"frank.li@...o.com" <frank.li@...o.com>
Subject: Re: [PATCH v3 4/4] ext4: support uncached buffered I/O

On Sun, Jun 29, 2025 at 11:41:12PM -0700, hch@...radead.org wrote:
> On Fri, Jun 27, 2025 at 06:03:09PM +0100, Matthew Wilcox wrote:
> > On Fri, Jun 27, 2025 at 11:03:13AM +0000, 陈涛涛 Taotao Chen wrote:
> > I think this needs to be:
> > 
> > 	if (iocb && iocb->ki_flags & IOCB_DONTCACHE)
> > 
> > because it's legit to call write_begin with a NULL argument.  The
> > 'file' was always an optional argument, and we should preserve that
> > optionality with this transformation.
> 
> write_begin and write_end are only callbacks through helpers called
> by the file system.  So if the file system never passes a NULL
> file/kiocb it doesn't need to check for it.

Sure, but some of those helpers are non-obvious, like page_symlink().