Re: Expected getdents behaviour

[Jan Blunck <jblunck@suse.de>]

On Thu, Sep 15, Anton Altaparmakov wrote:

> 
> That is completely untrue.  It is up to the user.  The file position in
> a directory is completely up to the caller and in particular when a
> directory is modified the file position in that directory is not changed
> by the filesystem.  Doing this would in fact be impossible since the
> creation/deletion in the kernel has no access to all the "struct file"s
> with which a directory has been opened.
> 

No, thats not true. The file position in a regular (flat) file is completely
up to the user. "Thanks" to the short-comings of POSIX on not defining the
functions on directories, the file position in a directory is completely up to
the file system. Due to that fact, modern file systems don't need to provide
a "flat" view (in terms of sequential access to a directory file) on
them. Although, the file system must guarantee, that readdir's must not fail
because of changes directory contents. AFAIR ext2 is achieving this through
not shrinking directories while the filesystem is online.

Regards,
	Jan

-- 
Jan Blunck                                               jblunck@suse.de
SuSE LINUX AG - A Novell company
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D-90409 Nürnberg                                      http://www.suse.de
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