On Tue, Jan 03, 2012 at 01:46:24PM +0100, Jan Kara wrote:
> Hello,
>
> On Tue 03-01-12 02:31:52, Djalal Harouni wrote:
> >
> > The EXT{3,4}_IOC_SETVERSION ioctl() updates the inode without i_mutex,
> > this can lead to a race with the other operations that update the same
> > inode.
> >
> > Patch tested.
> Thanks for the patch but I don't quite understand the problem.
> i_generation is set when:
> a) inode is loaded from disk
> b) inode is allocated
> c) in SETVERSION ioctl
>
> The only thing that can race here seems to be c) against c) and that is
> racy with i_mutex as well. So what problems do you exactly observe without
> the patch?
Right, but what about the related i_ctime change ? (i_ctime is updated in
other places...)
The i_ctime update must reflect the _appropriate_ inode modification
operation. This is why IMHO we should protect them to avoid a lost update.
BTW the i_generation which is used by NFS and fuse filesystems is updated
even if the inode is marked immutable, is this the intended behaviour?
> Honza
Thanks for your response.
--
tixxdz
http://opendz.org
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