On Thu, Apr 03, 2014 at 04:48:11PM -0400, Mark Lord wrote: > On 14-04-03 03:30 PM, J. Bruce Fields wrote: > > On Thu, Apr 03, 2014 at 01:51:06PM -0400, Mark Lord wrote: > >> On 14-04-03 01:16 PM, J. Bruce Fields wrote: > >>> On Thu, Apr 03, 2014 at 12:33:55PM -0400, Mark Lord wrote: > >>>> This commit from linux-3.14 breaks our NFS-root clients here: > >>>> > >>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6e14b46b91fee8a049b0940333ce13a820beaaa5 > >>>> > >>>> > >>>> - *p++ = htonl((u32) stat->mode); > >>>> + *p++ = htonl((u32) (stat->mode & S_IALLUGO)); > >>>> > >>>> > >>>> Reverting the one-liner above (on the server) fixes it for us, > >>>> as does reverting back to linux-3.13.8 on the server. > >>>> > >>>> The NFS-root clients are on PowerPC (big-endian) architecture, > >>>> running linux-3.12.16. The NFS server is on an Intel PC running linux-3.14. > >>>> > >>>> ACL is completely disabled on server and client, > >>>> and we're using NFSv2/v3. No support for v4. > >>>> > >>>> I instrumented the function to see what other bits were being cleared > >>>> by the (stat->mode & S_IALLUGO) masking. The results are attached. > >>> > >>> Hm, it sounds like a bug in the client if it's depending on those high > >>> bits. > >> > >> But only for mounting / starting up from the nfsroot, it seems. > >> I wonder if there's an unusual code path for that in there? > >> The regular stuff looks mostly fine: > >> > >> p = xdr_decode_ftype3(p, &fmode); > >> fattr->mode = (be32_to_cpup(p++) & ~S_IFMT) | fmode; > > > > Hm, but that's in nfs3xdr.c; in nfs2xdr.c we have just > > > > fattr->mode = be32_to_cpup(p+); > > > > and NFSv2 is the default for nfsroot. Do you have some reason to > > believe you're not using NFSv2? > > Oh, the client here was using NFS2, absolutely. > I just don't know my way around the code very well yet. :) > > But that mask in nfs3xdr.c (client) doesn't match what the server side is using. Not sure there's anything to see there. Looking at include/uapi/linux/stat.h and include/linux/stat.h, if I'm doing this right... S_ISFMT is 0170000 S_IALLUGO is 0007777 So they're 16-bit complements. And we're storing the result in a short? --b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
