Re: [PATCH 25/28] VFS: statfs(64) shouldn't follow last componentsymlink

From: Mike Waychison
Date: Mon Oct 25 2004 - 10:28:34 EST


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Christoph Hellwig wrote:
> On Mon, Oct 25, 2004 at 10:51:11AM -0400, Mike Waychison wrote:
>
>>Mount-related userspace tools will require the ability to detect whether what
>>looks like a regular directory is actually a autofs trigger. To handle this,
>>tools can statfs a given directory and check to see if statfs->f_type ==
>>AUTOFSNG_SUPER_MAGIC before walking into the directory (and causing the a
>>filesystem to automount).
>>
>>To make this happen, we cannot allow statfs to follow_link.
>>
>>NOTE: This may break any userspace that assumes it can statfs across a
>>last-component symlink. I can't think of any real world breakage however, as
>>mount(8) will drop the real path in /etc/mtab and /proc/mounts will always
>>show the true path.
>
>
> Which means it's vetoed. It's a big change in syscall semantics. And
> propabably breaks SuS (for statvfs(3) which requires full symlink
> resolution when it just refers to a path on the filesystem.
>

Ya, I figured that would be the case. What do folks think about a
lstatfs(64)?

- --
Mike Waychison
Sun Microsystems, Inc.
1 (650) 352-5299 voice
1 (416) 202-8336 voice

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NOTICE: The opinions expressed in this email are held by me,
and may not represent the views of Sun Microsystems, Inc.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.5 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org

iD8DBQFBfRoUdQs4kOxk3/MRAgHoAKCApqvkE2hgLAJKXDkLWWJE7BqevgCfQlh9
BxBlFSMUPoo1VyOcntae7Y0=
=rR8G
-----END PGP SIGNATURE-----
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/