RPC-over-RDMA Version One transports have a limit on how large
a backward direction RPC (backchannel) message can be. Ensure
that the NFSv4.x CREATE_SESSION operation advertises the
correct value to servers.
Signed-off-by: Chuck Lever <[email protected]>
---
This patch makes the client advertise the maximum size of a
backchannel RPC message, which is 996 bytes with the current RDMA
transport implementation.
I wanted to propose this patch for v4.6, but it breaks
Linux-to-Linux NFSv4.1 over RDMA. When attempting a mount, the Linux
client reports this in its log:
NFS: state manager: lease expired failed on NFSv4 server klimt-ib with error 525
NFS: nfs4_discover_server_trunking unhandled error -512. Exiting with error EIO
Then the mount command hangs (interruptibly).
On the Linux server, CREATE_SESSION calls check_backchannel_attrs()
which checks the maxreq_sz and maxresp_sz on the backchannel and
returns NFS4ERR_TOOSMALL because it wants maxreq_sz to be larger
than 1044 bytes.
[ The client could do a better job of recovering, perhaps. Should it
fall back to NFSv4.0 if vers= was not specified, and otherwise
have mount exit with an error code? ]
We have:
#define NFSD_CB_MAX_REQ_SZ ((NFS4_enc_cb_recall_sz + \
RPC_MAX_HEADER_WITH_AUTH) * sizeof(__be32))
NFS4_enc_cb_recall_sz is 51 and RPC_MAX_HEADER_WITH_AUTH is 210.
The comment in check_backchannel_attrs() says:
/*
* These RPC_MAX_HEADER macros are overkill, especially since we
* don't even do gss on the backchannel yet. But this is still
* less than 1k. Tighten up this estimate in the unlikely event
* it turns out to be a problem for some client:
*/
It seems that "still less than 1k" is not strictly true.
To address this, a new minimum could be chosen that assumes that
RPC_AUTH_GSS is not going to be used for now.
Thoughts?
fs/nfs/nfs4proc.c | 10 ++++++----
include/linux/sunrpc/clnt.h | 1 +
include/linux/sunrpc/xprt.h | 1 +
net/sunrpc/clnt.c | 15 +++++++++++++++
net/sunrpc/xprtrdma/transport.c | 1 +
net/sunrpc/xprtsock.c | 4 ++++
6 files changed, 28 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 4bfc33a..a0e2cda 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7295,9 +7295,11 @@ int nfs4_proc_get_lease_time(struct nfs_client *clp, struct nfs_fsinfo *fsinfo)
* always set csa_cachethis to FALSE because the current implementation
* of the back channel DRC only supports caching the CB_SEQUENCE operation.
*/
-static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args)
+static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args,
+ struct rpc_clnt *clnt)
{
unsigned int max_rqst_sz, max_resp_sz;
+ unsigned int max_bc_payload = rpc_max_bc_payload(clnt);
max_rqst_sz = NFS_MAX_FILE_IO_SIZE + nfs41_maxwrite_overhead;
max_resp_sz = NFS_MAX_FILE_IO_SIZE + nfs41_maxread_overhead;
@@ -7315,8 +7317,8 @@ static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args)
args->fc_attrs.max_ops, args->fc_attrs.max_reqs);
/* Back channel attributes */
- args->bc_attrs.max_rqst_sz = PAGE_SIZE;
- args->bc_attrs.max_resp_sz = PAGE_SIZE;
+ args->bc_attrs.max_rqst_sz = max_bc_payload;
+ args->bc_attrs.max_resp_sz = max_bc_payload;
args->bc_attrs.max_resp_sz_cached = 0;
args->bc_attrs.max_ops = NFS4_MAX_BACK_CHANNEL_OPS;
args->bc_attrs.max_reqs = 1;
@@ -7420,7 +7422,7 @@ static int _nfs4_proc_create_session(struct nfs_client *clp,
};
int status;
- nfs4_init_channel_attrs(&args);
+ nfs4_init_channel_attrs(&args, clp->cl_rpcclient);
args.flags = (SESSION4_PERSIST | SESSION4_BACK_CHAN);
status = rpc_call_sync(session->clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 131032f..1cad92e 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -175,6 +175,7 @@ void rpc_setbufsize(struct rpc_clnt *, unsigned int, unsigned int);
int rpc_protocol(struct rpc_clnt *);
struct net * rpc_net_ns(struct rpc_clnt *);
size_t rpc_max_payload(struct rpc_clnt *);
+size_t rpc_max_bc_payload(struct rpc_clnt *);
unsigned long rpc_get_timeout(struct rpc_clnt *clnt);
void rpc_force_rebind(struct rpc_clnt *);
size_t rpc_peeraddr(struct rpc_clnt *, struct sockaddr *, size_t);
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 69ef5b3..d32c319 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -179,6 +179,7 @@ struct rpc_xprt {
size_t max_payload; /* largest RPC payload size,
in bytes */
+ size_t max_bc_payload; /* max bytes per bc payload */
unsigned int tsh_size; /* size of transport specific
header */
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index b7f2104..ac3dbde 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1335,6 +1335,21 @@ size_t rpc_max_payload(struct rpc_clnt *clnt)
EXPORT_SYMBOL_GPL(rpc_max_payload);
/**
+ * rpc_max_bc_payload - Get maximum backchannel payload size, in bytes
+ * @clnt: RPC client to query
+ */
+size_t rpc_max_bc_payload(struct rpc_clnt *clnt)
+{
+ size_t ret;
+
+ rcu_read_lock();
+ ret = rcu_dereference(clnt->cl_xprt)->max_bc_payload;
+ rcu_read_unlock();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(rpc_max_bc_payload);
+
+/**
* rpc_get_timeout - Get timeout for transport in units of HZ
* @clnt: RPC client to query
*/
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index b1b009f..06fe152 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -402,6 +402,7 @@ xprt_setup_rdma(struct xprt_create *args)
xprt->max_payload <<= PAGE_SHIFT;
dprintk("RPC: %s: transport data payload maximum: %zu bytes\n",
__func__, xprt->max_payload);
+ xprt->max_bc_payload = cdata.inline_rsize - RPCRDMA_HDRLEN_MIN;
if (!try_module_get(THIS_MODULE))
goto out4;
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index fde2138..910e192 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2781,6 +2781,7 @@ static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
xprt->prot = 0;
xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
+ xprt->max_bc_payload = PAGE_SIZE;
xprt->bind_timeout = XS_BIND_TO;
xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
@@ -2852,6 +2853,7 @@ static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
xprt->tsh_size = 0;
/* XXX: header size can vary due to auth type, IPv6, etc. */
xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
+ xprt->max_bc_payload = PAGE_SIZE;
xprt->bind_timeout = XS_BIND_TO;
xprt->reestablish_timeout = XS_UDP_REEST_TO;
@@ -2931,6 +2933,7 @@ static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
xprt->prot = IPPROTO_TCP;
xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
+ xprt->max_bc_payload = PAGE_SIZE;
xprt->bind_timeout = XS_BIND_TO;
xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
@@ -3000,6 +3003,7 @@ static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
xprt->prot = IPPROTO_TCP;
xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
+ xprt->max_bc_payload = PAGE_SIZE;
xprt->timeout = &xs_tcp_default_timeout;
/* backchannel */
On Fri, Feb 12, 2016 at 11:52 AM, Chuck Lever <[email protected]> wrote:
> RPC-over-RDMA Version One transports have a limit on how large
> a backward direction RPC (backchannel) message can be. Ensure
> that the NFSv4.x CREATE_SESSION operation advertises the
> correct value to servers.
>
> Signed-off-by: Chuck Lever <[email protected]>
> ---
>
> This patch makes the client advertise the maximum size of a
> backchannel RPC message, which is 996 bytes with the current RDMA
> transport implementation.
>
> I wanted to propose this patch for v4.6, but it breaks
> Linux-to-Linux NFSv4.1 over RDMA. When attempting a mount, the Linux
> client reports this in its log:
>
> NFS: state manager: lease expired failed on NFSv4 server klimt-ib with error 525
> NFS: nfs4_discover_server_trunking unhandled error -512. Exiting with error EIO
>
> Then the mount command hangs (interruptibly).
Agreed: We should have nfs4_handle_reclaim_lease_error() call
nfs_mark_client_ready() on all fatal errors during session
initialisation (i.e. as long as we're still in
NFS_CS_SESSION_INITING).
> On the Linux server, CREATE_SESSION calls check_backchannel_attrs()
> which checks the maxreq_sz and maxresp_sz on the backchannel and
> returns NFS4ERR_TOOSMALL because it wants maxreq_sz to be larger
> than 1044 bytes.
>
> [ The client could do a better job of recovering, perhaps. Should it
> fall back to NFSv4.0 if vers= was not specified, and otherwise
> have mount exit with an error code? ]
>
> We have:
>
> #define NFSD_CB_MAX_REQ_SZ ((NFS4_enc_cb_recall_sz + \
> RPC_MAX_HEADER_WITH_AUTH) * sizeof(__be32))
>
> NFS4_enc_cb_recall_sz is 51 and RPC_MAX_HEADER_WITH_AUTH is 210.
>
> The comment in check_backchannel_attrs() says:
>
> /*
> * These RPC_MAX_HEADER macros are overkill, especially since we
> * don't even do gss on the backchannel yet. But this is still
> * less than 1k. Tighten up this estimate in the unlikely event
> * it turns out to be a problem for some client:
> */
>
> It seems that "still less than 1k" is not strictly true.
>
> To address this, a new minimum could be chosen that assumes that
> RPC_AUTH_GSS is not going to be used for now.
>
> Thoughts?
Why make this a transport variable? It seems more appropriate to just
have it be a per-transport function.
>
>
> fs/nfs/nfs4proc.c | 10 ++++++----
> include/linux/sunrpc/clnt.h | 1 +
> include/linux/sunrpc/xprt.h | 1 +
> net/sunrpc/clnt.c | 15 +++++++++++++++
> net/sunrpc/xprtrdma/transport.c | 1 +
> net/sunrpc/xprtsock.c | 4 ++++
> 6 files changed, 28 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 4bfc33a..a0e2cda 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -7295,9 +7295,11 @@ int nfs4_proc_get_lease_time(struct nfs_client *clp, struct nfs_fsinfo *fsinfo)
> * always set csa_cachethis to FALSE because the current implementation
> * of the back channel DRC only supports caching the CB_SEQUENCE operation.
> */
> -static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args)
> +static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args,
> + struct rpc_clnt *clnt)
> {
> unsigned int max_rqst_sz, max_resp_sz;
> + unsigned int max_bc_payload = rpc_max_bc_payload(clnt);
>
> max_rqst_sz = NFS_MAX_FILE_IO_SIZE + nfs41_maxwrite_overhead;
> max_resp_sz = NFS_MAX_FILE_IO_SIZE + nfs41_maxread_overhead;
> @@ -7315,8 +7317,8 @@ static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args)
> args->fc_attrs.max_ops, args->fc_attrs.max_reqs);
>
> /* Back channel attributes */
> - args->bc_attrs.max_rqst_sz = PAGE_SIZE;
> - args->bc_attrs.max_resp_sz = PAGE_SIZE;
> + args->bc_attrs.max_rqst_sz = max_bc_payload;
> + args->bc_attrs.max_resp_sz = max_bc_payload;
> args->bc_attrs.max_resp_sz_cached = 0;
> args->bc_attrs.max_ops = NFS4_MAX_BACK_CHANNEL_OPS;
> args->bc_attrs.max_reqs = 1;
> @@ -7420,7 +7422,7 @@ static int _nfs4_proc_create_session(struct nfs_client *clp,
> };
> int status;
>
> - nfs4_init_channel_attrs(&args);
> + nfs4_init_channel_attrs(&args, clp->cl_rpcclient);
> args.flags = (SESSION4_PERSIST | SESSION4_BACK_CHAN);
>
> status = rpc_call_sync(session->clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
> diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
> index 131032f..1cad92e 100644
> --- a/include/linux/sunrpc/clnt.h
> +++ b/include/linux/sunrpc/clnt.h
> @@ -175,6 +175,7 @@ void rpc_setbufsize(struct rpc_clnt *, unsigned int, unsigned int);
> int rpc_protocol(struct rpc_clnt *);
> struct net * rpc_net_ns(struct rpc_clnt *);
> size_t rpc_max_payload(struct rpc_clnt *);
> +size_t rpc_max_bc_payload(struct rpc_clnt *);
> unsigned long rpc_get_timeout(struct rpc_clnt *clnt);
> void rpc_force_rebind(struct rpc_clnt *);
> size_t rpc_peeraddr(struct rpc_clnt *, struct sockaddr *, size_t);
> diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
> index 69ef5b3..d32c319 100644
> --- a/include/linux/sunrpc/xprt.h
> +++ b/include/linux/sunrpc/xprt.h
> @@ -179,6 +179,7 @@ struct rpc_xprt {
>
> size_t max_payload; /* largest RPC payload size,
> in bytes */
> + size_t max_bc_payload; /* max bytes per bc payload */
> unsigned int tsh_size; /* size of transport specific
> header */
>
> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> index b7f2104..ac3dbde 100644
> --- a/net/sunrpc/clnt.c
> +++ b/net/sunrpc/clnt.c
> @@ -1335,6 +1335,21 @@ size_t rpc_max_payload(struct rpc_clnt *clnt)
> EXPORT_SYMBOL_GPL(rpc_max_payload);
>
> /**
> + * rpc_max_bc_payload - Get maximum backchannel payload size, in bytes
> + * @clnt: RPC client to query
> + */
> +size_t rpc_max_bc_payload(struct rpc_clnt *clnt)
> +{
> + size_t ret;
> +
> + rcu_read_lock();
> + ret = rcu_dereference(clnt->cl_xprt)->max_bc_payload;
> + rcu_read_unlock();
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(rpc_max_bc_payload);
> +
> +/**
> * rpc_get_timeout - Get timeout for transport in units of HZ
> * @clnt: RPC client to query
> */
> diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
> index b1b009f..06fe152 100644
> --- a/net/sunrpc/xprtrdma/transport.c
> +++ b/net/sunrpc/xprtrdma/transport.c
> @@ -402,6 +402,7 @@ xprt_setup_rdma(struct xprt_create *args)
> xprt->max_payload <<= PAGE_SHIFT;
> dprintk("RPC: %s: transport data payload maximum: %zu bytes\n",
> __func__, xprt->max_payload);
> + xprt->max_bc_payload = cdata.inline_rsize - RPCRDMA_HDRLEN_MIN;
>
> if (!try_module_get(THIS_MODULE))
> goto out4;
> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
> index fde2138..910e192 100644
> --- a/net/sunrpc/xprtsock.c
> +++ b/net/sunrpc/xprtsock.c
> @@ -2781,6 +2781,7 @@ static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
> xprt->prot = 0;
> xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
> xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
> + xprt->max_bc_payload = PAGE_SIZE;
>
> xprt->bind_timeout = XS_BIND_TO;
> xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
> @@ -2852,6 +2853,7 @@ static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
> xprt->tsh_size = 0;
> /* XXX: header size can vary due to auth type, IPv6, etc. */
> xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
> + xprt->max_bc_payload = PAGE_SIZE;
>
> xprt->bind_timeout = XS_BIND_TO;
> xprt->reestablish_timeout = XS_UDP_REEST_TO;
> @@ -2931,6 +2933,7 @@ static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
> xprt->prot = IPPROTO_TCP;
> xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
> xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
> + xprt->max_bc_payload = PAGE_SIZE;
>
> xprt->bind_timeout = XS_BIND_TO;
> xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
> @@ -3000,6 +3003,7 @@ static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
> xprt->prot = IPPROTO_TCP;
> xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
> xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
> + xprt->max_bc_payload = PAGE_SIZE;
> xprt->timeout = &xs_tcp_default_timeout;
>
> /* backchannel */
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> On Feb 12, 2016, at 12:27 PM, Trond Myklebust <[email protected]> wrote:
>
> On Fri, Feb 12, 2016 at 11:52 AM, Chuck Lever <[email protected]> wrote:
>> RPC-over-RDMA Version One transports have a limit on how large
>> a backward direction RPC (backchannel) message can be. Ensure
>> that the NFSv4.x CREATE_SESSION operation advertises the
>> correct value to servers.
>>
>> Signed-off-by: Chuck Lever <[email protected]>
>> ---
>>
>> This patch makes the client advertise the maximum size of a
>> backchannel RPC message, which is 996 bytes with the current RDMA
>> transport implementation.
>>
>> I wanted to propose this patch for v4.6, but it breaks
>> Linux-to-Linux NFSv4.1 over RDMA. When attempting a mount, the Linux
>> client reports this in its log:
>>
>> NFS: state manager: lease expired failed on NFSv4 server klimt-ib with error 525
>> NFS: nfs4_discover_server_trunking unhandled error -512. Exiting with error EIO
>>
>> Then the mount command hangs (interruptibly).
>
> Agreed: We should have nfs4_handle_reclaim_lease_error() call
> nfs_mark_client_ready() on all fatal errors during session
> initialisation (i.e. as long as we're still in
> NFS_CS_SESSION_INITING).
>
>> On the Linux server, CREATE_SESSION calls check_backchannel_attrs()
>> which checks the maxreq_sz and maxresp_sz on the backchannel and
>> returns NFS4ERR_TOOSMALL because it wants maxreq_sz to be larger
>> than 1044 bytes.
>>
>> [ The client could do a better job of recovering, perhaps. Should it
>> fall back to NFSv4.0 if vers= was not specified, and otherwise
>> have mount exit with an error code? ]
>>
>> We have:
>>
>> #define NFSD_CB_MAX_REQ_SZ ((NFS4_enc_cb_recall_sz + \
>> RPC_MAX_HEADER_WITH_AUTH) * sizeof(__be32))
>>
>> NFS4_enc_cb_recall_sz is 51 and RPC_MAX_HEADER_WITH_AUTH is 210.
>>
>> The comment in check_backchannel_attrs() says:
>>
>> /*
>> * These RPC_MAX_HEADER macros are overkill, especially since we
>> * don't even do gss on the backchannel yet. But this is still
>> * less than 1k. Tighten up this estimate in the unlikely event
>> * it turns out to be a problem for some client:
>> */
>>
>> It seems that "still less than 1k" is not strictly true.
>>
>> To address this, a new minimum could be chosen that assumes that
>> RPC_AUTH_GSS is not going to be used for now.
>>
>> Thoughts?
>
> Why make this a transport variable? It seems more appropriate to just
> have it be a per-transport function.
I assume you are talking about the addition of the
max_bc_payload field to struct rpc_xprt. Sure, I
can add another method to rpc_xprt_ops instead,
and have rpc_max_bc_payload invoke that.
>> fs/nfs/nfs4proc.c | 10 ++++++----
>> include/linux/sunrpc/clnt.h | 1 +
>> include/linux/sunrpc/xprt.h | 1 +
>> net/sunrpc/clnt.c | 15 +++++++++++++++
>> net/sunrpc/xprtrdma/transport.c | 1 +
>> net/sunrpc/xprtsock.c | 4 ++++
>> 6 files changed, 28 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>> index 4bfc33a..a0e2cda 100644
>> --- a/fs/nfs/nfs4proc.c
>> +++ b/fs/nfs/nfs4proc.c
>> @@ -7295,9 +7295,11 @@ int nfs4_proc_get_lease_time(struct nfs_client *clp, struct nfs_fsinfo *fsinfo)
>> * always set csa_cachethis to FALSE because the current implementation
>> * of the back channel DRC only supports caching the CB_SEQUENCE operation.
>> */
>> -static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args)
>> +static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args,
>> + struct rpc_clnt *clnt)
>> {
>> unsigned int max_rqst_sz, max_resp_sz;
>> + unsigned int max_bc_payload = rpc_max_bc_payload(clnt);
>>
>> max_rqst_sz = NFS_MAX_FILE_IO_SIZE + nfs41_maxwrite_overhead;
>> max_resp_sz = NFS_MAX_FILE_IO_SIZE + nfs41_maxread_overhead;
>> @@ -7315,8 +7317,8 @@ static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args)
>> args->fc_attrs.max_ops, args->fc_attrs.max_reqs);
>>
>> /* Back channel attributes */
>> - args->bc_attrs.max_rqst_sz = PAGE_SIZE;
>> - args->bc_attrs.max_resp_sz = PAGE_SIZE;
>> + args->bc_attrs.max_rqst_sz = max_bc_payload;
>> + args->bc_attrs.max_resp_sz = max_bc_payload;
>> args->bc_attrs.max_resp_sz_cached = 0;
>> args->bc_attrs.max_ops = NFS4_MAX_BACK_CHANNEL_OPS;
>> args->bc_attrs.max_reqs = 1;
>> @@ -7420,7 +7422,7 @@ static int _nfs4_proc_create_session(struct nfs_client *clp,
>> };
>> int status;
>>
>> - nfs4_init_channel_attrs(&args);
>> + nfs4_init_channel_attrs(&args, clp->cl_rpcclient);
>> args.flags = (SESSION4_PERSIST | SESSION4_BACK_CHAN);
>>
>> status = rpc_call_sync(session->clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
>> diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
>> index 131032f..1cad92e 100644
>> --- a/include/linux/sunrpc/clnt.h
>> +++ b/include/linux/sunrpc/clnt.h
>> @@ -175,6 +175,7 @@ void rpc_setbufsize(struct rpc_clnt *, unsigned int, unsigned int);
>> int rpc_protocol(struct rpc_clnt *);
>> struct net * rpc_net_ns(struct rpc_clnt *);
>> size_t rpc_max_payload(struct rpc_clnt *);
>> +size_t rpc_max_bc_payload(struct rpc_clnt *);
>> unsigned long rpc_get_timeout(struct rpc_clnt *clnt);
>> void rpc_force_rebind(struct rpc_clnt *);
>> size_t rpc_peeraddr(struct rpc_clnt *, struct sockaddr *, size_t);
>> diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
>> index 69ef5b3..d32c319 100644
>> --- a/include/linux/sunrpc/xprt.h
>> +++ b/include/linux/sunrpc/xprt.h
>> @@ -179,6 +179,7 @@ struct rpc_xprt {
>>
>> size_t max_payload; /* largest RPC payload size,
>> in bytes */
>> + size_t max_bc_payload; /* max bytes per bc payload */
>> unsigned int tsh_size; /* size of transport specific
>> header */
>>
>> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
>> index b7f2104..ac3dbde 100644
>> --- a/net/sunrpc/clnt.c
>> +++ b/net/sunrpc/clnt.c
>> @@ -1335,6 +1335,21 @@ size_t rpc_max_payload(struct rpc_clnt *clnt)
>> EXPORT_SYMBOL_GPL(rpc_max_payload);
>>
>> /**
>> + * rpc_max_bc_payload - Get maximum backchannel payload size, in bytes
>> + * @clnt: RPC client to query
>> + */
>> +size_t rpc_max_bc_payload(struct rpc_clnt *clnt)
>> +{
>> + size_t ret;
>> +
>> + rcu_read_lock();
>> + ret = rcu_dereference(clnt->cl_xprt)->max_bc_payload;
>> + rcu_read_unlock();
>> + return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(rpc_max_bc_payload);
>> +
>> +/**
>> * rpc_get_timeout - Get timeout for transport in units of HZ
>> * @clnt: RPC client to query
>> */
>> diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
>> index b1b009f..06fe152 100644
>> --- a/net/sunrpc/xprtrdma/transport.c
>> +++ b/net/sunrpc/xprtrdma/transport.c
>> @@ -402,6 +402,7 @@ xprt_setup_rdma(struct xprt_create *args)
>> xprt->max_payload <<= PAGE_SHIFT;
>> dprintk("RPC: %s: transport data payload maximum: %zu bytes\n",
>> __func__, xprt->max_payload);
>> + xprt->max_bc_payload = cdata.inline_rsize - RPCRDMA_HDRLEN_MIN;
>>
>> if (!try_module_get(THIS_MODULE))
>> goto out4;
>> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
>> index fde2138..910e192 100644
>> --- a/net/sunrpc/xprtsock.c
>> +++ b/net/sunrpc/xprtsock.c
>> @@ -2781,6 +2781,7 @@ static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
>> xprt->prot = 0;
>> xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
>> xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
>> + xprt->max_bc_payload = PAGE_SIZE;
>>
>> xprt->bind_timeout = XS_BIND_TO;
>> xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
>> @@ -2852,6 +2853,7 @@ static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
>> xprt->tsh_size = 0;
>> /* XXX: header size can vary due to auth type, IPv6, etc. */
>> xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
>> + xprt->max_bc_payload = PAGE_SIZE;
>>
>> xprt->bind_timeout = XS_BIND_TO;
>> xprt->reestablish_timeout = XS_UDP_REEST_TO;
>> @@ -2931,6 +2933,7 @@ static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
>> xprt->prot = IPPROTO_TCP;
>> xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
>> xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
>> + xprt->max_bc_payload = PAGE_SIZE;
>>
>> xprt->bind_timeout = XS_BIND_TO;
>> xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
>> @@ -3000,6 +3003,7 @@ static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
>> xprt->prot = IPPROTO_TCP;
>> xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
>> xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
>> + xprt->max_bc_payload = PAGE_SIZE;
>> xprt->timeout = &xs_tcp_default_timeout;
>>
>> /* backchannel */
>>
>> --
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> --
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--
Chuck Lever