LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: "Hans-Jürgen Koch" <hjk@linutronix.de>
To: Jan Engelhardt <jengelh@computergmbh.de>
Cc: Andi Kleen <andi@firstfloor.org>,
	Jasper Bryant-Greene <jasper@unix.geek.nz>,
	rzryyvzy <rzryyvzy@trashmail.net>,
	linux-kernel@vger.kernel.org
Subject: Re: Is there a "blackhole" /dev/null directory?
Date: Thu, 14 Feb 2008 16:30:01 +0100	[thread overview]
Message-ID: <20080214163001.31918e32@dilbert.local> (raw)
In-Reply-To: <Pine.LNX.4.64.0802141620330.694@fbirervta.pbzchgretzou.qr>

Am Thu, 14 Feb 2008 16:23:37 +0100 (CET)
schrieb Jan Engelhardt <jengelh@computergmbh.de>:

> 
> On Feb 14 2008 16:19, Hans-Jürgen Koch wrote:
> >> 
> >> Q: What if a program attempts to mkdir /dev/nullmnt/foo to just
> >>    create a file /dev/nullmnt/foo/barfile?
> >> A: /dev/nullmnt/foo must continue to exist or be accepted for a
> >> while, or perhaps for eternity.
> >
> >Well, the problem seems to be that a "directory" is not just data but
> >also contains metadata. While it's easy to write data to /dev/null,
> >you cannot simply discard metadata associated with a directory. So,
> >such a "/dev/null-directory" would have to remember metadata (at
> >least all created filenames including subdirectories) in the same
> >way as other filesystems do. Only file _content_ can be discarded.
> 
> Not even that. Suppose a userspace program (whose output you'd like
> to discard) does:

[...]

Well, if an application wants to read back written data, you can never
use such a thing, not even in simple cases where the
existing /dev/null would be enough. 

> }
> 
> >To be honest, I still cannot see many sensible usecases for that...
> 
> I agree.

Good :-)

Hans

  reply	other threads:[~2008-02-14 15:30 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-14  9:30 rzryyvzy
2008-02-14  9:39 ` Jasper Bryant-Greene
2008-02-14  9:46   ` Andi Kleen
2008-02-14 15:00     ` Jan Engelhardt
2008-02-14 15:19       ` Hans-Jürgen Koch
2008-02-14 15:23         ` Jan Engelhardt
2008-02-14 15:30           ` Hans-Jürgen Koch [this message]
2008-02-15 19:25       ` Bill Davidsen
2008-02-14 12:16   ` Mika Lawando
2008-02-14 15:06     ` linux-os (Dick Johnson)
     [not found] <9WIJE-1Nr-11@gated-at.bofh.it>
2008-02-14 17:16 ` Bodo Eggert
     [not found] ` <9WIJO-1Nr-19@gated-at.bofh.it>
     [not found]   ` <9WITv-286-21@gated-at.bofh.it>
     [not found]     ` <9WNTa-2x3-17@gated-at.bofh.it>
     [not found]       ` <9WOch-2Wk-3@gated-at.bofh.it>
2008-02-15  1:15         ` Bodo Eggert

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20080214163001.31918e32@dilbert.local \
    --to=hjk@linutronix.de \
    --cc=andi@firstfloor.org \
    --cc=jasper@unix.geek.nz \
    --cc=jengelh@computergmbh.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rzryyvzy@trashmail.net \
    --subject='Re: Is there a "blackhole" /dev/null directory?' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).