Re: [PATCH 2/2] check ATTR_SIZE contraints in inode_change_ok

[Steven Whitehouse <steve@chygwyn.com>]

Hi,

On Wed, 2010-06-09 at 12:07 +0200, Christoph Hellwig wrote:
> On Wed, Jun 09, 2010 at 11:41:21AM +0200, Jan Kara wrote:
> >   That's a good point. For all local filesystems I know, holding i_mutex is
> > enough for having stable i_size. But for clustered filesystems it
> > definitely isn't. They have to hold cluster locks to be able to reliably
> > check current i_size (at least OCFS2 does). Looking at what
> > inode_newsize_ok currently does, i_size is only used to decide whether
> > we need to check for rlimit or not. So we could falsely miss this
> > check (other node is truncating the file below new offset)... Hmm, OK, so
> > we really need the cluster lock...
> >   BTW: Mark, don't we need the cluster lock also for the permission
> > checks in inode_change_ok? Otherwise we could see:
> 
> Yes, we should have it for all of the checks.  It would be good if
> the cluster folks came up with proper patches for vfs.git #for-next
> to fix up the cluster locking for all of ->setattr.
> 
I already have such a patch, and as per your request, I'm only waiting
for your changes in the same area to hit mainline before I merge it into
my git tree to avoid conflicts in -next. If you'd like to merge the
changes via the vfs tree instead, thats ok too, but let me know which,

Steve.