Subject: Re: Is there a "blackhole" /dev/null directory?
From: Jasper Bryant-Greene <jasper@unix.geek.nz>
To: rzryyvzy <rzryyvzy@trashmail.net>
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <20080214093051.7240852AB0E31@trashmail.net>
References: <20080214093051.7240852AB0E31@trashmail.net>
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Date: Thu, 14 Feb 2008 22:39:17 +1300
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On Thu, 2008-02-14 at 10:30 +0100, rzryyvzy wrote:
> /dev/null is often very useful, specially if programs force to save data =
in some file. But some programs like to creates different temporary file na=
mes, so /dev/null could no more work.
>=20
> What is with a "/dev/null"-directory?
> I mean a "blackhole pseudo directory" which eats every write to null.
>=20
> Here is how it could work:
> mount -t nulldir nulldir /dev/nulldir
>=20
> Now if a program does a create(2),
> it creates in the memory the file with its fd.
> Then if a program does a write(2) to the fd, it eats the writes and give =
out fakely it has written the number of bytes.
> When the program calls does a close(2) of the fd, then the complete inode=
 is deleted in the memory.
>=20
> The directory should  be permanently empty except for the inodes with ope=
n file descriptors. So only inode information would be temporary saved in t=
his "nulldir tmpfs" directory.
>=20
> Is there already existing a possibility to create a null directory?

This could be done fairly trivially with FUSE, and IMHO is a good use
for FUSE because since you're just throwing most data away, performance
is not a concern.

-j

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