Re: linux-3.14 nfsd regression

J. Bruce Fields
2014-04-03T20:15:39Z

On Thu, Apr 03, 2014 at 01:51:06PM -0400, Mark Lord wrote:
> On 14-04-03 01:16 PM, J. Bruce Fields wrote:
> > The original behavior was in practice harmless and changing it broke
> > something, so I think we should definitely just revert this patch.
>
> Yup. Who?

I'll submit this soon.

--b.

Author: J. Bruce Fields <bfields@redhat.com>
Date: Thu Apr 3 15:10:35 2014 -0400

nfsd: revert v2 half of "nfsd: don't return high mode bits"

This reverts the part of commit 6e14b46b91fee8a049b0940333ce13a820beaaa5
that changes NFSv2 behavior.

Mark Lord found that it broke nfs-root for Linux clients, because it
broke NFSv2.

In fact, from RFC 1094:

"Notice that the file type is specified both in the mode bits
and in the file type. This is really a bug in the protocol and
will be fixed in future versions."

So NFSv2 clients really are expected to depend on the high bits of the
mode.

Cc: stable@kernel.org
Reported-by: Mark Lord <mlord@pobox.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index b17d932..9c769a4 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -152,7 +152,7 @@ encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,
type = (stat->mode & S_IFMT);

*p++ = htonl(nfs_ftypes[type >> 12]);
- *p++ = htonl((u32) (stat->mode & S_IALLUGO));
+ *p++ = htonl((u32) stat->mode);
*p++ = htonl((u32) stat->nlink);
*p++ = htonl((u32) from_kuid(&init_user_ns, stat->uid));
*p++ = htonl((u32) from_kgid(&init_user_ns, stat->gid));