Re: [ 16/46] NFSv4.1: Remove a bogus BUG_ON() innfs4_layoutreturn_done

[Greg Kroah-Hartman]

On Sun, Sep 16, 2012 at 05:33:03PM +0100, Ben Hutchings wrote:
> On Wed, 2012-09-12 at 16:39 -0700, Greg Kroah-Hartman wrote:
> > From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
> > 
> > 3.0-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> > 
> > commit 47fbf7976e0b7d9dcdd799e2a1baba19064d9631 upstream.
> > 
> > Ever since commit 0a57cdac3f (NFSv4.1 send layoutreturn to fence
> > disconnected data server) we've been sending layoutreturn calls
> > while there is potentially still outstanding I/O to the data
> > servers. The reason we do this is to avoid races between replayed
> > writes to the MDS and the original writes to the DS.
> > 
> > When this happens, the BUG_ON() in nfs4_layoutreturn_done can
> > be triggered because it assumes that we would never call
> > layoutreturn without knowing that all I/O to the DS is
> > finished. The fix is to remove the BUG_ON() now that the
> > assumptions behind the test are obsolete.
> > 
> > Reported-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
> > Reported-by: Tigran Mkrtchyan <tigran.mkrtchyan@xxxxxxx>
> > Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> [...]
> 
> The upstream commit has:
> 
>     Cc: stable@xxxxxxxxxxxxxxx [>=3.5]
> 
> and so I ignored it for 3.2.  Is it actually needed for the earlier
> stable series?

Crud, I missed that somehow :(

Trond, should I revert this in 3.0 and 3.4 stable kernels?

thanks,

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/