[PATCH v2 4/4] net: add NFSv1 support

Pali Rohár pali at kernel.org
Sat Jun 24 11:05:11 CEST 2023


On Sunday 11 June 2023 17:24:50 Christian Gmeiner wrote:
> Am So., 11. Juni 2023 um 17:10 Uhr schrieb Pali Rohár <pali at kernel.org>:
> >
> > On Sunday 11 June 2023 16:57:07 Christian Gmeiner wrote:
> > > Hello
> > >
> > > >
> > > > Hello! I must admit that this patch is broken and does not add any NFSv1
> > > > support. Just look below....
> > > >
> > >
> > > So .. let see what happend here.
> > >
> > > > On Friday 10 March 2023 10:51:55 Christian Gmeiner wrote:
> > > > > From: Thomas RIENOESSL <thomas.rienoessl at bachmann.info>
> > > > >
> > > > > NFSv1 support added by Christian Gmeiner, Thomas Rienoessl,
> > > > > September 27, 2018. As of now, NFSv3 is the default choice.
> > > > > if the server does not support NFSv3, we fall back to
> > > > > versions 2 or 1.
> > > > >
> > > > > Signed-off-by: Thomas RIENOESSL <thomas.rienoessl at bachmann.info>
> > > > > ---
> > > > >  net/nfs.c | 42 +++++++++++++++++++++++++++++++++---------
> > > > >  1 file changed, 33 insertions(+), 9 deletions(-)
> > > > >
> > > > > diff --git a/net/nfs.c b/net/nfs.c
> > > > > index 21cae52f35..7a8887ef23 100644
> > > > > --- a/net/nfs.c
> > > > > +++ b/net/nfs.c
> > > > > @@ -26,6 +26,10 @@
> > > > >   * NFSv2 is still used by default. But if server does not support NFSv2, then
> > > > >   * NFSv3 is used, if available on NFS server. */
> > > > >
> > > > > +/* NOTE 5: NFSv1 support added by Christian Gmeiner, Thomas Rienoessl,
> > > > > + * September 27, 2018. As of now, NFSv3 is the default choice. If the server
> > > > > + * does not support NFSv3, we fall back to versions 2 or 1. */
> > > > > +
> > > > >  #include <common.h>
> > > > >  #include <command.h>
> > > > >  #include <display_options.h>
> > > > > @@ -78,6 +82,7 @@ static char nfs_path_buff[2048];
> > > > >
> > > > >  enum nfs_version {
> > > > >       NFS_UNKOWN = 0,
> > > > > +     NFS_V1 = 1,
> > > > >       NFS_V2 = 2,
> > > > >       NFS_V3 = 3,
> > > > >  };
> > > > > @@ -192,6 +197,7 @@ static void rpc_req(int rpc_prog, int rpc_proc, uint32_t *data, int datalen)
> > > > >       switch (rpc_prog) {
> > > > >       case PROG_NFS:
> > > > >               switch (choosen_nfs_version) {
> > > > > +             case NFS_V1:
> > > > >               case NFS_V2:
> > > > >                       rpc_pkt.u.call.vers = htonl(2);
> > > >
> > > > So if NFSv1 is chosen then this code uses NFSv2. This is either rebasing
> > > > problem or just prove that this patch does not add any NFSv1 support.
> > > >
> > > > >                       break;
> > > > > @@ -205,8 +211,26 @@ static void rpc_req(int rpc_prog, int rpc_proc, uint32_t *data, int datalen)
> > > > >                       break;
> > > > >               }
> > > > >               break;
> > > > > -     case PROG_PORTMAP:
> > > > >       case PROG_MOUNT:
> > > > > +             switch (choosen_nfs_version) {
> > > > > +             case NFS_V1:
> > > > > +                     rpc_pkt.u.call.vers = htonl(1);
> > > > > +                     break;
> > > >
> > > > And later here for NFSv1 we are trying to use Mount Server, which NFSv1
> > > > did not use at all. So this patch really does not have to work with old
> > > > NFSv1 servers.
> > > >
> > > > Instead NFSv1 uses NFSPROC_ROOT RPC call exported by NFS server.
> > > > (See that this RPC call is deprecated in NFSv2 and MNT server is used
> > > > in NFSv2 instead.)
> > > >
> > > > MNTv1 is service used by the NFSv2 and it returns NFSv2 file handles
> > > > (not NFSv1 file handles). MNTv2 is also used by NFSv2 and as addition to
> > > > MNTv1, it adds DIRPATH rpc call. So if NFSv2 does not need to use
> > > > DIRPATH then it is fine to use just MNTv1 in NFSv2.
> > > >
> > > > > +
> > > > > +             case NFS_V2:
> > > > > +                     rpc_pkt.u.call.vers = htonl(2);
> > > > > +                     break;
> > > > > +
> > > > > +             case NFS_V3:
> > > > > +                     rpc_pkt.u.call.vers = htonl(3);
> > > > > +                     break;
> > > > > +
> > > > > +             case NFS_UNKOWN:
> > > > > +                     /* nothing to do */
> > > > > +                     break;
> > > > > +             }
> > > > > +             break;
> > > > > +     case PROG_PORTMAP:
> > > > >       default:
> > > > >               rpc_pkt.u.call.vers = htonl(2); /* portmapper is version 2 */
> > > > >       }
> > > > > @@ -311,7 +335,7 @@ static void nfs_readlink_req(void)
> > > > >       p = &(data[0]);
> > > > >       p = rpc_add_credentials(p);
> > > > >
> > > > > -     if (choosen_nfs_version == NFS_V2) {
> > > > > +     if (choosen_nfs_version != NFS_V3) {
> > > > >               memcpy(p, filefh, NFS_FHSIZE);
> > > > >               p += (NFS_FHSIZE / 4);
> > > > >       } else { /* NFS_V3 */
> > > > > @@ -340,7 +364,7 @@ static void nfs_lookup_req(char *fname)
> > > > >       p = &(data[0]);
> > > > >       p = rpc_add_credentials(p);
> > > > >
> > > > > -     if (choosen_nfs_version == NFS_V2) {
> > > > > +     if (choosen_nfs_version != NFS_V3) {
> > > > >               memcpy(p, dirfh, NFS_FHSIZE);
> > > > >               p += (NFS_FHSIZE / 4);
> > > > >               *p++ = htonl(fnamelen);
> > > > > @@ -380,7 +404,7 @@ static void nfs_read_req(int offset, int readlen)
> > > > >       p = &(data[0]);
> > > > >       p = rpc_add_credentials(p);
> > > > >
> > > > > -     if (choosen_nfs_version == NFS_V2) {
> > > > > +     if (choosen_nfs_version != NFS_V3) {
> > > > >               memcpy(p, filefh, NFS_FHSIZE);
> > > > >               p += (NFS_FHSIZE / 4);
> > > > >               *p++ = htonl(offset);
> > > > > @@ -410,13 +434,13 @@ static void nfs_send(void)
> > > > >
> > > > >       switch (nfs_state) {
> > > > >       case STATE_PRCLOOKUP_PROG_MOUNT_REQ:
> > > > > -             if (choosen_nfs_version == NFS_V2)
> > > > > +             if (choosen_nfs_version != NFS_V3)
> > > > >                       rpc_lookup_req(PROG_MOUNT, 1);
> > > > >               else  /* NFS_V3 */
> > > > >                       rpc_lookup_req(PROG_MOUNT, 3);
> > > > >               break;
> > > > >       case STATE_PRCLOOKUP_PROG_NFS_REQ:
> > > > > -             if (choosen_nfs_version == NFS_V2)
> > > > > +             if (choosen_nfs_version != NFS_V3)
> > > > >                       rpc_lookup_req(PROG_NFS, 2);
> > > > >               else  /* NFS_V3 */
> > > > >                       rpc_lookup_req(PROG_NFS, 3);
> > > > > @@ -457,7 +481,7 @@ static int rpc_handle_error(struct rpc_t *rpc_pkt)
> > > > >                       const int min = ntohl(rpc_pkt->u.reply.data[0]);
> > > > >                       const int max = ntohl(rpc_pkt->u.reply.data[1]);
> > > > >
> > > > > -                     if (max < NFS_V2 || max > NFS_V3 || min > NFS_V3) {
> > > > > +                     if (max < NFS_V1 || max > NFS_V3 || min > NFS_V3) {
> > > > >                               puts("*** ERROR: NFS version not supported");
> > > > >                               debug(": Requested: V%d, accepted: min V%d - max V%d\n",
> > > > >                                     choosen_nfs_version,
> > > > > @@ -588,7 +612,7 @@ static int nfs_lookup_reply(uchar *pkt, unsigned len)
> > > > >       if (ret)
> > > > >               return ret;
> > > > >
> > > > > -     if (choosen_nfs_version == NFS_V2) {
> > > > > +     if (choosen_nfs_version != NFS_V3) {
> > > > >               if (((uchar *)&(rpc_pkt.u.reply.data[0]) - (uchar *)(&rpc_pkt) + NFS_FHSIZE) > len)
> > > > >                       return -NFS_RPC_DROP;
> > > > >               memcpy(filefh, rpc_pkt.u.reply.data + 1, NFS_FHSIZE);
> > > > > @@ -712,7 +736,7 @@ static int nfs_read_reply(uchar *pkt, unsigned len)
> > > > >       if (!(nfs_offset % ((NFS_READ_SIZE / 2) * 10)))
> > > > >               putc('#');
> > > > >
> > > > > -     if (choosen_nfs_version == NFS_V2) {
> > > > > +     if (choosen_nfs_version != NFS_V3) {
> > > > >               rlen = ntohl(rpc_pkt.u.reply.data[18]);
> > > > >               data_ptr = (uchar *)&(rpc_pkt.u.reply.data[19]);
> > > > >       } else {  /* NFS_V3 */
> > > > > --
> > > > > 2.39.2
> > > > >
> > > >
> > > > And looking at the other changes here, there is really _no_ code which
> > > > adds NFSv1 support.
> > > >
> > > > So what is this patch doing? The only thing which it does is that for
> > > > NFSv1 requests it does NFSv2 calls. On every place is just check that
> > > > choosen_nfs_version is not NFS_V3.
> > > >
> > > > Which just basically duplicates NFSv2 to be used two times.
> > > >
> > >  > I would suggest to revisit this patch (who reviewed it at all?) and
> > > > either fix it or revert it. And of course properly test it. (And I
> > > > really curious where you find NFSv1 server because Linux has already
> > > > removed also NFSv2 support from userspace...)
> > >
> > > Soo. I had a look at RFC 1094 and this patch adds version one of the
> > > mount protocol.
> > > I am quite unhappy that we got into this state, but the company I
> > > worked for uses the
> > > term NFSv1 for this in all their configuration tools etc.
> > > What would you suggest to improve this situation?
> >
> > Suggestion: Revert this one patch, then figure out what is needed to be
> > supported (describe all details what kind of protocol and what packets
> > needs to be send and received), find a way and discuss how to implement
> > it and prepare patch for the review.
> 
> Here comes a big problem: "find a way and discuss how to implement it
> and prepare patch for the review."
> I am not sure if there is really someone interested in discussion
> about this topic and it is
> even harder to find someone that reviews U-Boot patches. And this is
> not specific to networking stuff.
> 
> I can prepare a patch that reworks the current implementation (without
> a revert) and send it out.

So how to handle this issue? Release date of u-boot is coming and this
issue have not been addressed or discussed yet.

As I wrote I can help in this area, but I doubt that we will be able to
everything before release.

Tom, could you do something here?

> >
> > If you, who sent this patch, are unhappy about this patch, and also Peter
> > and me pointed issues, then this patch really should not have land into
> > git master branch in this form. It means that nobody is happy with this
> > patch.
> 
> To clarify a fact: I am happy with the patch. I am unhappy with the
> wrong "naming" that my old
> employer used and influenced this patch. Also the company is shipping
> thousands of devices per
> year where these patches are used.
> 
> -- 
> greets
> --
> Christian Gmeiner, MSc
> 
> https://christian-gmeiner.info/privacypolicy


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