Re: Expected getdents behaviour

[Anton Altaparmakov <aia21@cam.ac.uk>]

On Thu, 15 Sep 2005, Charles P. Wright wrote:
> On Thu, 2005-09-15 at 22:00 +0100, Anton Altaparmakov wrote:
> > The only problem again is when the reference to the 
> > directory entry will be released in the case that no further readdir and 
> > no close ever comes.  It causes the fs to be unmountable for example 
> > and the file belonging to the directory entry to be undeletable...
> Anton,
> 
> If no further readdir "ever" comes, and the file is never closed, the
> file system will not be unmountable to begin with.  It is just like
> opening and never closing a normal file, you keep the file system busy.

Er, yes, that is true.
 
> I don't see the connection between the extra per-open-file state you
> need to save, and the argument that this opens up up for a DoS.

When I say DoS I mean "user triggerable OOM" on a large dirctory.  Say you 
have a directory with 2^30 files in it and you need to snapshot it or 
something each time a user does opendir() + readir().  You would OOM very 
quickly...

Best regards,

	Anton
-- 
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net
WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/