Re: NFS write OOPS with 2.6.29.2

[Holger Kiehl]

On Mon, 11 May 2009, Trond Myklebust wrote:

> On Mon, 2009-05-11 at 09:24 +0000, Holger Kiehl wrote:
> > On Sun, 10 May 2009, Trond Myklebust wrote:
> >
> > > On Sat, 2009-05-09 at 19:16 +0000, Holger Kiehl wrote:
> > > > On Mon, 4 May 2009, Andrew Morton wrote:
> > > >
> > > > > (cc linux-nfs)
> > > > >
> > > > > On Sun, 3 May 2009 16:03:38 +0000 (GMT) Holger Kiehl <Holger.Kiehl@xxxxxx> wrote:
> > > > >
> > > > > > Hello
> > > > > >
> > > > > > With plain kernel 2.6.29.2 I get the following OOPS (several of them) when
> > > > > > writing lots of small files on the client system:
> > > > > >
> > > > > >     May  3 18:48:34 obelix kernel: ------------[ cut here ]------------
> > > > > >     May  3 18:48:34 obelix kernel: kernel BUG at fs/nfs/write.c:252!
> > > > >
> > > > > I think this is a well-know bug, and fixes should be available in 2.6.29.3?
> > > > Thanks for this information. I just tried 2.6.29.3 and it still oopses.
> > > > Are there any patches I can try?
> > >
> > > The attached backports against 2.6.29 are untested, but they are known
> > > to compile at least. Could you give them a try?
> > Thanks. They do compile but when there is a mmap on the NFS drive the
> > program gets a SIGBUS:
> >
> >     unlink("/home/afdbench/afd2/fifodir/AFD_ACTIVE") = 0
> >     close(3)                                = 0
> >     open("/home/afdbench/afd2/fifodir/AFD_ACTIVE", O_RDWR|O_CREAT|O_TRUNC|O_CLOEXEC, 0600) = 3
> >     lseek(3, 78, SEEK_SET)                  = 78
> >     write(3, "\377"..., 1)                  = 1
> >     mmap(NULL, 78, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0) = 0x7f8045cdb000
> >     --- SIGBUS (Bus error) @ 0 (0) ---
> >
> > This was with 2.6.29.3 plus the patches you send me.
> >
> > Holger
>
> Oh, duh... You need this little patchlet too.
Thanks! Now it works. One more problem I have is with splice(). My
application reports the following error:

   splice() error : Invalid argument

When it is called as follows:

    if ((bytes_written = splice(fd_pipe[0], NULL, to_fd,
                                NULL, bytes_read,
                                SPLICE_F_MOVE | SPLICE_F_MORE)) == -1)

Or may I not use splice() over NFS?

Thanks,
Holger
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