Re: [PATCH 3/3] nfs: use ->mmap_prepare() to avoid an AB-BA deadlock

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, 2007-11-14 at 22:22 +0100, Nick Piggin wrote:
> On Wed, Nov 14, 2007 at 09:01:39PM +0100, Peter Zijlstra wrote:
> > Normal locking order is:
> > 
> >   i_mutex
> >     mmap_sem
> > 
> > However NFS's ->mmap hook, which is called under mmap_sem, can take i_mutex.
> > Avoid this potential deadlock by doing the work that requires i_mutex from
> > the new ->mmap_prepare().
> > 
> > [ Is this sufficient, or does it introduce a race? ]
> 
> Seems like an OK patchset in my opinion. I don't know much about NFS
> unfortunately, but I wonder what prevents the condition fixed by
> nfs_revalidate_mapping from happening again while the mmap is active...?

As the changelog might have suggested, I'm not overly sure of the nfs
requirements myself. I think it just does a best effort at getting the
pages coherent with other clients, and then hopes for the best.

I'll let Trond enlighten us further before I make an utter fool of
myself :-)

-
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux