lkml.org 
[lkml]   [2007]   [Mar]   [17]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
DateSat, 17 Mar 2007 12:53:37 +0200
From"Pekka Enberg" <>
SubjectRe: forced umount?
On 3/17/07, Mike Snitzer <snitzer@gmail.com> wrote:
> Thanks for the heads up; its good to see that Pekka Enberg's work has
> continued.  I actually stumbled onto that line of work earlier while
> searching for more info on Tigran Aivazian's forced unmount (badfs)
> patches:
> http://lwn.net/Articles/192632/

FYI, the revoke implementation have since been changed to follow the
badfs-style approach of the forced unmount patches. However, there are
some problems with the forced unmount patches that are now fixed in
the revoke implementation:

  - You can't use munmap() to take down shared memory mappings because the
    application can accidentally remap something completely different
to that region.
  - The ->f_light bits slow down other fget_light() users and  there's
a race between
    fcheck_files() and set_f_light().
  - The operation can live-lock if a malicious process keeps forking. The revoke
    implementation solves this by revoking in two passes: (1) take
down the descriptors
    and (2) take down the actual inodes.

                           Pekka
-
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/

\
 
 \ /
  Last update: 2007-03-17 11:57    [from the cache]
©2003-2008