2010-05-14 22:45:23

by J.Bruce Fields

[permalink] [raw]
Subject: [PATCH 1/2] nfs4: minor callback code simplification

Note the position in the version array doesn't have to match the actual
rpc version number.

Signed-off-by: J. Bruce Fields <[email protected]>
---
fs/nfsd/nfs4callback.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 77bc9d3..b91bdee 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -430,7 +430,6 @@ static struct rpc_version nfs_cb_version4 = {
};

static struct rpc_version * nfs_cb_version[] = {
- NULL,
&nfs_cb_version4,
};

@@ -471,7 +470,7 @@ int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *cb)
.timeout = &timeparms,
.program = &cb_program,
.prognumber = cb->cb_prog,
- .version = nfs_cb_version[1]->number,
+ .version = 1,
.authflavor = clp->cl_flavor,
.flags = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
.client_name = clp->cl_principal,
--
1.7.0.4



2010-05-18 22:48:49

by J.Bruce Fields

[permalink] [raw]
Subject: Re: [PATCH 2/2] nfsd4: fix callback program version

On Fri, May 14, 2010 at 06:45:23PM -0400, J. Bruce Fields wrote:
> The 4.1 rfc actually specifices that the callback program must have
> version 4.
>
> As far as I can tell, this was unspecified in rfc 3530. But it looks to
> me like the NFSv4 client only ever accepted version 1!
>
> Newer linux clients allow either 1 or 4, for either minor version.
>
> So, the safest approach seems to be to use version 1 for 4.0 clients,
> and version 4 for 4.1 clients.

OK, following further discussion on the ietf list, let's stick to
version 1 for now and just add a comment.

--b.

commit b7299f44394336f51b526247a870d47d28f4f97c
Author: J. Bruce Fields <[email protected]>
Date: Fri May 14 17:57:35 2010 -0400

nfs4: minor callback code simplification, comment

Note the position in the version array doesn't have to match the actual
rpc version number--to me it seems clearer to maintain the distinction.

Also document choice of rpc callback version number, as discussed in
e.g. http://www.ietf.org/mail-archive/web/nfsv4/current/msg07985.html
and followups.

Signed-off-by: J. Bruce Fields <[email protected]>

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 77bc9d3..eb78e7e 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -424,13 +424,19 @@ static struct rpc_procinfo nfs4_cb_procedures[] = {
};

static struct rpc_version nfs_cb_version4 = {
+/*
+ * Note on the callback rpc program version number: despite language in rfc
+ * 5661 section 18.36.3 requiring servers to use 4 in this field, the
+ * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
+ * in practice that appears to be what implementations use. The section
+ * 18.36.3 language is expected to be fixed in an erratum.
+ */
.number = 1,
.nrprocs = ARRAY_SIZE(nfs4_cb_procedures),
.procs = nfs4_cb_procedures
};

static struct rpc_version * nfs_cb_version[] = {
- NULL,
&nfs_cb_version4,
};

@@ -471,7 +477,7 @@ int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *cb)
.timeout = &timeparms,
.program = &cb_program,
.prognumber = cb->cb_prog,
- .version = nfs_cb_version[1]->number,
+ .version = 0,
.authflavor = clp->cl_flavor,
.flags = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
.client_name = clp->cl_principal,

2010-05-14 22:45:23

by J.Bruce Fields

[permalink] [raw]
Subject: [PATCH 2/2] nfsd4: fix callback program version

The 4.1 rfc actually specifices that the callback program must have
version 4.

As far as I can tell, this was unspecified in rfc 3530. But it looks to
me like the NFSv4 client only ever accepted version 1!

Newer linux clients allow either 1 or 4, for either minor version.

So, the safest approach seems to be to use version 1 for 4.0 clients,
and version 4 for 4.1 clients.

Signed-off-by: J. Bruce Fields <[email protected]>
---
fs/nfsd/nfs4callback.c | 21 +++++++++++++++++++--
1 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index b91bdee..bf79031 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -423,13 +423,29 @@ static struct rpc_procinfo nfs4_cb_procedures[] = {
PROC(CB_RECALL, COMPOUND, enc_cb_recall, dec_cb_recall),
};

-static struct rpc_version nfs_cb_version4 = {
+/*
+ * RFC 5661 section 18.36.3 (in the description of csa_cb_program),
+ * requires the callback rpc program version number to be 4. RFC 3530
+ * leaves this unspecified, however, pre-2.6.33 Linux NFSv4 clients
+ * required the version number to be 1.
+ * Therefore, the safest seems to be use version 1 for 4.0 clients and
+ * version 4 for 4.1 clients. Therefore, we define both versions:
+ */
+
+static struct rpc_version nfs_cb_version1 = {
.number = 1,
.nrprocs = ARRAY_SIZE(nfs4_cb_procedures),
.procs = nfs4_cb_procedures
};

+static struct rpc_version nfs_cb_version4 = {
+ .number = 4,
+ .nrprocs = ARRAY_SIZE(nfs4_cb_procedures),
+ .procs = nfs4_cb_procedures
+};
+
static struct rpc_version * nfs_cb_version[] = {
+ &nfs_cb_version1,
&nfs_cb_version4,
};

@@ -470,7 +486,8 @@ int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *cb)
.timeout = &timeparms,
.program = &cb_program,
.prognumber = cb->cb_prog,
- .version = 1,
+ /* See the comment before the nfs_cb_version1 definition: */
+ .version = cb->cb_minorversion ? 1 : 0,
.authflavor = clp->cl_flavor,
.flags = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
.client_name = clp->cl_principal,
--
1.7.0.4