Message-ID: <1350198545.1915.233.camel@kjgkr>
Subject: Re: [PATCH 11/16] f2fs: add inode operations for special inodes
From: Jaegeuk Kim <jaegeuk.kim@gmail.com>
To: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
        =?euc-kr?Q?=B1=E8=C0=E7=B1=D8?= <jaegeuk.kim@samsung.com>,
        viro@zeniv.linux.org.uk, "'Theodore Ts'o'" <tytso@mit.edu>,
        gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
        chur.lee@samsung.com, cm224.lee@samsung.com,
        jooyoung.hwang@samsung.com
Date: Sun, 14 Oct 2012 16:09:05 +0900
In-Reply-To: <E4F29864-3D97-4839-BC4E-6DCFDAC5447C@dubeyko.com>
References: <001201cda2f1$633db960$29b92c20$%kim@samsung.com>
	 <201210132052.09835.arnd@arndb.de>
	 <E4F29864-3D97-4839-BC4E-6DCFDAC5447C@dubeyko.com>
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2012-10-14 (일), 02:21 +0400, Vyacheslav Dubeyko:
> On Oct 14, 2012, at 12:52 AM, Arnd Bergmann wrote:
> 
> > On Friday 05 October 2012, 김재극 wrote:
> >> +const char *media_ext_lists[] = {
> >> +       "jpg",
> >> +       "gif",
> >> +       "png",
> >> +       "avi",
> >> +       "divx",
> >> +       "mp4",
> >> +       "mp3",
> >> ...
> > 
> >> + * Set multimedia files as cold files for hot/cold data separation
> >> + */
> >> +static inline void set_cold_file(struct inode *inode, const unsigned char *name)
> >> +{
> >> +       const char **extlist = media_ext_lists;
> >> +
> >> +       while (*extlist) {
> >> +               if (!is_multimedia_file(name, *extlist)) {
> >> +                       F2FS_I(inode)->is_cold = 1;
> >> +                       break;
> >> +               }
> >> +               extlist++;
> >> +       }
> >> +}
> > 
> > This is a very clever way of categorizing files by their name, but I wonder if hardcoding
> > the list of file name extensions at in the kernel source is the best strategy. Generally
> > I would consider this to be a policy that should be configurable by the user.
> > 
> > Unfortunately I can't think of a good interface to configure this, but maybe someone
> > else has a useful idea. Maybe the list can be stored in the superblock and get written
> > at mkfs time from the same defaults, but with the option of overriding it using
> > a debugfs tool.
> > 
> 
> By the way, how about extended attributes? It is possible to save in extended attribute a hint about file's content nature during creation operation or later. Moreover, extended attribute gives possibility to change hint after renaming operation, for example.
> 

I think xattr is not a proper way to communicate between file system and
users.
How about fadvise()?

> With the best regards,
> Vyacheslav Dubeyko.
> 
> > 	Arnd
> > --
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-- 
Jaegeuk Kim
Samsung

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