On Mon, 10 Mar 2014 17:27:27 -0400 Steve Dickson <SteveD@xxxxxxxxxx> wrote: > Hey Neil, > > On 02/23/2014 10:23 PM, NeilBrown wrote: > > > > Protocol negotiation in mount.nfs does not correctly negotiate with a > > server which only supports NFSv3 and UDP. > > > > When mount.nfs attempts an NFSv4 mount and fails with ECONNREFUSED > > it does not fall back to NFSv3, as this is not recognised as a > > "does not support NFSv4" error. > > However ECONNREFUSED is a clear indication that the server doesn't > > support TCP, and ipso facto does not support NFSv4. > > So ECONNREFUSED should trigger a fallback from v4 to v2/3. > What server are you running this against? Not sure, either Linux 3.2 or 3.11. I don't know exactly what server the bug was reported to me against, I'm guessing some NAS thing. https://bugzilla.novell.com/show_bug.cgi?id=863749 > > I've started an number of different servers with the "-T -N 4" > rpc.nfsd flags here is what I've found: > > When I doing the mount without "-o v3" mount option, the mount > hangs (forever) in the server discovering trunking code. > > Mount older server like RHEL5 or RHEL6 the mount (w/out the patch) > success because RPC: Program not registered is return which causes > the fallback to happen > > So I'm assuming you are using a recent Linux server because > I do see the ECONNREFUSED with that server, but because I > have to use the -o v3 this patch does not seem to help. > Basically I spin in this loop: > > mount.nfs: prog 100003, trying vers=3, prot=6 > mount.nfs: trying 127.0.0.1 prog 100003 vers 3 prot TCP port 2049 > mount.nfs: portmap query failed: RPC: Remote system error - Connection refused > > I have not debug as to what is going on, but it does not look like > the patch is doing what is expect... > > steved. With a 3.11.10 client talking to a 3.2.0 server I run rpc.nfsd 0 rpc.nfsd -T -N4 on the server, then rpcinfo -p SERVER | grep nfs shows 100003 2 udp 2049 nfs 100003 3 udp 2049 nfs 100227 2 udp 2049 nfs_acl 100227 3 udp 2049 nfs_acl On client I run mount -v SERVER:/PATH /mnt and I get mount.nfs: trying text-based options 'vers=4,addr=192.168.1.3,clientaddr=192.168.1.2' mount.nfs: mount(2): Connection refused repeating ever 10 seconds or so. It eventually times out after 2 minutes. Same client to a 3.10 server I get the same behaviour. 3.2.0 client and 3.10 server, same behaviour again. I have noticed that sometimes when I stop the NFS server the registration with rpcbind doesn't go away. Not often, but sometimes. I wonder if that could be confusing something? Can you check that nfsv4 has been de-registered from rpcbind? I note you are getting the error: > mount.nfs: portmap query failed: RPC: Remote system error - Connection refused This seems to suggest that rpcbind isn't running. Yet when I kill rpcbind and try a v3 mount I get mount.nfs: portmap query failed: RPC: Unable to receive - Connection refused which is slightly different, so presumably there is a different cause in your case. Maybe you could turn on some rpcdebug tracing to see what is happening? Thanks, NeilBrown > > > > > However ECONNREFUSED may simply indicate that NFSv4 isn't supported > > *yet*. i.e. the server is still booting and isn't responding to NFS > > requests yet. So if we subsequently find that NFSv3 is supported, we > > need to check with rpcbind to confirm that NFSv4 really isn't > > supported. > > If rpcbind reports that v4 is not supported after reporting that v3 > > is, we can safely use v4. If it reports that v4 is supported, we need > > to retry v4. > > > > One line in this patch requires explanation. It is > > + save_pmap.pm_vers = 4; > > > > This is needed as nfs_probe_nfsport is entered with pm_vers already > > set, by the line > > nfs_pmap->pm_vers = mntvers_to_nfs(*probe_vers); > > in nfs_probe_bothports(). This makes the passing of probe_nfs3_only > > and probe_nfs2_only to nfs_probe_port() in nfs_probe_nfsport() > > pointless, and the passing of probe_nfs4_only in the new code > > ineffectual, without resetting pm_vers. > > > > The setting of pm_vers to mntvers_to_nfs() should probably be removed, > > but as we don't have any regression tests, doing this would be unwise. > > > > Signed-off-by: NeilBrown <neilb@xxxxxxx> > > Reported-by: Carsten Ziepke <kieltux@xxxxxxxxx> > > > > diff --git a/utils/mount/network.c b/utils/mount/network.c > > index 2fdd2c051be7..0521d5f6709f 100644 > > --- a/utils/mount/network.c > > +++ b/utils/mount/network.c > > @@ -149,6 +149,11 @@ static const unsigned int probe_tcp_first[] = { > > 0, > > }; > > > > +static const unsigned int probe_tcp_only[] = { > > + IPPROTO_TCP, > > + 0, > > +}; > > + > > static const unsigned long probe_nfs2_only[] = { > > 2, > > 0, > > @@ -159,6 +164,11 @@ static const unsigned long probe_nfs3_only[] = { > > 0, > > }; > > > > +static const unsigned long probe_nfs4_only[] = { > > + 4, > > + 0, > > +}; > > + > > static const unsigned long probe_mnt1_first[] = { > > 1, > > 2, > > @@ -611,18 +621,34 @@ out_ok: > > * returned; rpccreateerr.cf_stat is set to reflect the nature of the error. > > */ > > static int nfs_probe_nfsport(const struct sockaddr *sap, const socklen_t salen, > > - struct pmap *pmap) > > + struct pmap *pmap, int checkv4) > > { > > if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port) > > return 1; > > > > if (nfs_mount_data_version >= 4) { > > const unsigned int *probe_proto; > > + int ret; > > + struct pmap save_pmap; > > + struct sockaddr_storage save_sa; > > > > probe_proto = nfs_default_proto(); > > - > > - return nfs_probe_port(sap, salen, pmap, > > - probe_nfs3_only, probe_proto); > > + memcpy(&save_pmap, pmap, sizeof(save_pmap)); > > + memcpy(&save_sa, sap, salen); > > + > > + ret = nfs_probe_port(sap, salen, pmap, > > + probe_nfs3_only, probe_proto); > > + if (!ret || !checkv4 || probe_proto != probe_tcp_first) > > + return ret; > > + save_pmap.pm_vers = 4; > > + ret = nfs_probe_port((struct sockaddr*)&save_sa, salen, &save_pmap, > > + probe_nfs4_only, probe_tcp_only); > > + if (ret) { > > + rpc_createerr.cf_stat = RPC_FAILED; > > + rpc_createerr.cf_error.re_errno = EAGAIN; > > + return 0; > > + } > > + return 1; > > } else > > return nfs_probe_port(sap, salen, pmap, > > probe_nfs2_only, probe_udp_only); > > @@ -671,7 +697,7 @@ static int nfs_probe_version_fixed(const struct sockaddr *mnt_saddr, > > const socklen_t nfs_salen, > > struct pmap *nfs_pmap) > > { > > - if (!nfs_probe_nfsport(nfs_saddr, nfs_salen, nfs_pmap)) > > + if (!nfs_probe_nfsport(nfs_saddr, nfs_salen, nfs_pmap, 0)) > > return 0; > > return nfs_probe_mntport(mnt_saddr, mnt_salen, mnt_pmap); > > } > > @@ -686,6 +712,8 @@ static int nfs_probe_version_fixed(const struct sockaddr *mnt_saddr, > > * @nfs_salen: length of NFS server's address > > * @nfs_pmap: IN: partially filled-in NFS RPC service tuple; > > * OUT: fully filled-in NFS RPC service tuple > > + * @checkv4: Flag indicating that if v3 is available we must also > > + * check v4, and if that is available, set re_errno to EAGAIN. > > * > > * Returns 1 and fills in both @pmap structs if the requested service > > * ports are unambiguous and pingable. Otherwise zero is returned; > > @@ -696,7 +724,8 @@ int nfs_probe_bothports(const struct sockaddr *mnt_saddr, > > struct pmap *mnt_pmap, > > const struct sockaddr *nfs_saddr, > > const socklen_t nfs_salen, > > - struct pmap *nfs_pmap) > > + struct pmap *nfs_pmap, > > + int checkv4) > > { > > struct pmap save_nfs, save_mnt; > > const unsigned long *probe_vers; > > @@ -717,7 +746,7 @@ int nfs_probe_bothports(const struct sockaddr *mnt_saddr, > > > > for (; *probe_vers; probe_vers++) { > > nfs_pmap->pm_vers = mntvers_to_nfs(*probe_vers); > > - if (nfs_probe_nfsport(nfs_saddr, nfs_salen, nfs_pmap) != 0) { > > + if (nfs_probe_nfsport(nfs_saddr, nfs_salen, nfs_pmap, checkv4) != 0) { > > mnt_pmap->pm_vers = *probe_vers; > > if (nfs_probe_mntport(mnt_saddr, mnt_salen, mnt_pmap) != 0) > > return 1; > > @@ -757,7 +786,7 @@ int probe_bothports(clnt_addr_t *mnt_server, clnt_addr_t *nfs_server) > > return nfs_probe_bothports(mnt_addr, sizeof(mnt_server->saddr), > > &mnt_server->pmap, > > nfs_addr, sizeof(nfs_server->saddr), > > - &nfs_server->pmap); > > + &nfs_server->pmap, 0); > > } > > > > /** > > diff --git a/utils/mount/network.h b/utils/mount/network.h > > index 9c75856c9ca8..d7636d7c54a6 100644 > > --- a/utils/mount/network.h > > +++ b/utils/mount/network.h > > @@ -42,7 +42,7 @@ static const struct timeval RETRY_TIMEOUT = { 3, 0 }; > > int probe_bothports(clnt_addr_t *, clnt_addr_t *); > > int nfs_probe_bothports(const struct sockaddr *, const socklen_t, > > struct pmap *, const struct sockaddr *, > > - const socklen_t, struct pmap *); > > + const socklen_t, struct pmap *, int); > > int nfs_gethostbyname(const char *, struct sockaddr_in *); > > int nfs_lookup(const char *hostname, const sa_family_t family, > > struct sockaddr *sap, socklen_t *salen); > > diff --git a/utils/mount/stropts.c b/utils/mount/stropts.c > > index a642394d2f5a..1f4782563572 100644 > > --- a/utils/mount/stropts.c > > +++ b/utils/mount/stropts.c > > @@ -484,7 +484,7 @@ static int nfs_construct_new_options(struct mount_options *options, > > * FALSE is returned if some failure occurred. > > */ > > static int > > -nfs_rewrite_pmap_mount_options(struct mount_options *options) > > +nfs_rewrite_pmap_mount_options(struct mount_options *options, int checkv4) > > { > > union nfs_sockaddr nfs_address; > > struct sockaddr *nfs_saddr = &nfs_address.sa; > > @@ -534,7 +534,7 @@ nfs_rewrite_pmap_mount_options(struct mount_options *options) > > * negotiate. Bail now if we can't contact it. > > */ > > if (!nfs_probe_bothports(mnt_saddr, mnt_salen, &mnt_pmap, > > - nfs_saddr, nfs_salen, &nfs_pmap)) { > > + nfs_saddr, nfs_salen, &nfs_pmap, checkv4)) { > > errno = ESPIPE; > > if (rpc_createerr.cf_stat == RPC_PROGNOTREGISTERED) > > errno = EOPNOTSUPP; > > @@ -595,7 +595,8 @@ static int nfs_sys_mount(struct nfsmount_info *mi, struct mount_options *opts) > > } > > > > static int nfs_do_mount_v3v2(struct nfsmount_info *mi, > > - struct sockaddr *sap, socklen_t salen) > > + struct sockaddr *sap, socklen_t salen, > > + int checkv4) > > { > > struct mount_options *options = po_dup(mi->options); > > int result = 0; > > @@ -637,7 +638,7 @@ static int nfs_do_mount_v3v2(struct nfsmount_info *mi, > > printf(_("%s: trying text-based options '%s'\n"), > > progname, *mi->extra_opts); > > > > - if (!nfs_rewrite_pmap_mount_options(options)) > > + if (!nfs_rewrite_pmap_mount_options(options, checkv4)) > > goto out_fail; > > > > result = nfs_sys_mount(mi, options); > > @@ -653,13 +654,13 @@ out_fail: > > * Returns TRUE if successful, otherwise FALSE. > > * "errno" is set to reflect the individual error. > > */ > > -static int nfs_try_mount_v3v2(struct nfsmount_info *mi) > > +static int nfs_try_mount_v3v2(struct nfsmount_info *mi, int checkv4) > > { > > struct addrinfo *ai; > > int ret = 0; > > > > for (ai = mi->address; ai != NULL; ai = ai->ai_next) { > > - ret = nfs_do_mount_v3v2(mi, ai->ai_addr, ai->ai_addrlen); > > + ret = nfs_do_mount_v3v2(mi, ai->ai_addr, ai->ai_addrlen, checkv4); > > if (ret != 0) > > return ret; > > > > @@ -793,7 +794,8 @@ static int nfs_autonegotiate(struct nfsmount_info *mi) > > result = nfs_try_mount_v4(mi); > > if (result) > > return result; > > - > > + > > +check_errno: > > switch (errno) { > > case EPROTONOSUPPORT: > > /* A clear indication that the server or our > > @@ -807,12 +809,24 @@ static int nfs_autonegotiate(struct nfsmount_info *mi) > > /* Linux servers prior to 2.6.25 may return > > * EPERM when NFS version 4 is not supported. */ > > goto fall_back; > > + case ECONNREFUSED: > > + /* UDP-Only servers won't support v4, but maybe it > > + * just isn't ready yet. So try v3, but double-check > > + * with rpcbind for v4. */ > > + result = nfs_try_mount_v3v2(mi, 1); > > + if (result == 0 && errno == EAGAIN) { > > + /* v4 server seems to be registered now. */ > > + result = nfs_try_mount_v4(mi); > > + if (result == 0 && errno != ECONNREFUSED) > > + goto check_errno; > > + } > > + return result; > > default: > > return result; > > } > > > > fall_back: > > - return nfs_try_mount_v3v2(mi); > > + return nfs_try_mount_v3v2(mi, 0); > > } > > > > /* > > @@ -831,7 +845,7 @@ static int nfs_try_mount(struct nfsmount_info *mi) > > break; > > case 2: > > case 3: > > - result = nfs_try_mount_v3v2(mi); > > + result = nfs_try_mount_v3v2(mi, 0); > > break; > > case 4: > > result = nfs_try_mount_v4(mi); > >
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