| Message ID | 20140404135842.GB17594@fieldses.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 4 Apr 2014 09:58:43 -0400 "J. Bruce Fields" <bfields@fieldses.org> wrote: > On Thu, Apr 03, 2014 at 07:21:46PM -0400, Jeff Layton wrote: > > So according to the RFC you have to encode both the mode bits and the > > ftype for v2. The type bits seem to be removed from the mode in NFSv3 > > though, so perhaps we should only be doing that masking in versions > > above v2? > > Right, the problematic patch applied the same mask in both v2 and v3 > cases, so I'm reverting just the v2 part (see below). > > > With a quick check, it looks like the v3 code doesn't rely on those bits > > and I imagine v4 doesn't either. > > > > It might also be nice to have the client v2 decode_fattr function to > > throw a warning if the server sends us mismatched type bits and ftype > > values. That would have helped us catch this sooner... > > Yes, that might be a reasonable thing to do, though I don't know if it's > worth it. > > --b. > > commit 35a8dff14e76c00e5b52140290cfb498dc2454a0 > 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)); Looks right... Reviewed-by: Jeff Layton <jlayton@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 14-04-04 09:58 AM, J. Bruce Fields wrote: > On Thu, Apr 03, 2014 at 07:21:46PM -0400, Jeff Layton wrote: >> So according to the RFC you have to encode both the mode bits and the >> ftype for v2. The type bits seem to be removed from the mode in NFSv3 >> though, so perhaps we should only be doing that masking in versions >> above v2? > > Right, the problematic patch applied the same mask in both v2 and v3 > cases, so I'm reverting just the v2 part (see below). > >> With a quick check, it looks like the v3 code doesn't rely on those bits >> and I imagine v4 doesn't either. >> >> It might also be nice to have the client v2 decode_fattr function to >> throw a warning if the server sends us mismatched type bits and ftype >> values. That would have helped us catch this sooner... > > Yes, that might be a reasonable thing to do, though I don't know if it's > worth it. > > --b. > > commit 35a8dff14e76c00e5b52140290cfb498dc2454a0 > 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)); > Still a regression in 3.14.2 now. Anyone got plans to push this patch out to mainline, as well as +stable ?
On Thu, May 01, 2014 at 07:50:34AM -0400, Mark Lord wrote: > Still a regression in 3.14.2 now. > Anyone got plans to push this patch out to mainline, as well as +stable ? This is upstream as 082f31a2169bd639785e45bf252f3d5bce0303c6 "nfsd: revert v2 half of "nfsd: don't return high mode bits"", with a cc to stable@kernel.org, so I assume it's just taking a little time for stable to pick it up. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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));