Re: [PATCH] ramfs: pretend dirent sizes

[Chris Wedgwood <cw@f00f.org>]

On Wed, Jul 20, 2005 at 01:21:27PM +0200, J?rn Engel wrote:

> To my understanding, you can lseek to any "proper" offset inside a
> directory.  Proper means that the offset marks the beginning of a
> new dirent (or end of file) in the interpretation of the filesystem.

But you can never tell where these are in general.

> Userspace doesn't have any means to figure out, which addresses are
> proper and which aren't.  Except that getdents(2) moves the fd
> offset to a proper address, which likely will remain proper until
> the fd is closed.

I don't see why or how this can be true in general (it might be, but I
don't see how myself).  If we are half way through scanning a
directory and people start messing with it we could end up somewhere
bogus (in which case f_op->readdir I guess is expected to try and do
something sane here?)

> Reopening the same directory may result in a formerly proper offset
> isn't anymore.

For that to be the case where is the state kept to ensure your current
offset is valid?

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