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

[Mike Waychison]

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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

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