lockd: document use of mon_id argument in SM_MON requests

[pandora-kernel.git] / fs / lockd / mon.c

diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index eb243ed..3935d7b 100644 (file)
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -10,6 +10,7 @@
 #include <linux/utsname.h>
 #include <linux/kernel.h>
 #include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/xprtsock.h>
 #include <linux/sunrpc/svc.h>
 #include <linux/lockd/lockd.h>
 #include <linux/lockd/sm_inter.h>
@@ -17,6 +18,8 @@
 
 #define NLMDBG_FACILITY                NLMDBG_MONITOR
 
+#define XDR_ADDRBUF_LEN                (20)
+
 static struct rpc_clnt *       nsm_create(void);
 
 static struct rpc_program      nsm_program;
@@ -61,6 +64,7 @@ nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res)
                        status);
        else
                status = 0;
+       rpc_shutdown_client(clnt);
  out:
        return status;
 }
@@ -131,14 +135,13 @@ nsm_create(void)
                .sin_port       = 0,
        };
        struct rpc_create_args args = {
-               .protocol       = IPPROTO_UDP,
+               .protocol       = XPRT_TRANSPORT_UDP,
                .address        = (struct sockaddr *)&sin,
                .addrsize       = sizeof(sin),
                .servername     = "localhost",
                .program        = &nsm_program,
                .version        = SM_VERSION,
                .authflavor     = RPC_AUTH_NULL,
-               .flags          = (RPC_CLNT_CREATE_ONESHOT),
        };
 
        return rpc_create(&args);
@@ -148,6 +151,70 @@ nsm_create(void)
  * XDR functions for NSM.
  */
 
+static __be32 *xdr_encode_nsm_string(__be32 *p, char *string)
+{
+       size_t len = strlen(string);
+
+       if (len > SM_MAXSTRLEN)
+               len = SM_MAXSTRLEN;
+       return xdr_encode_opaque(p, string, len);
+}
+
+/*
+ * "mon_name" specifies the host to be monitored.
+ *
+ * Linux uses a text version of the IP address of the remote
+ * host as the host identifier (the "mon_name" argument).
+ *
+ * Linux statd always looks up the canonical hostname first for
+ * whatever remote hostname it receives, so this works alright.
+ */
+static __be32 *xdr_encode_mon_name(__be32 *p, struct nsm_args *argp)
+{
+       char    buffer[XDR_ADDRBUF_LEN + 1];
+       char    *name = argp->mon_name;
+
+       if (!nsm_use_hostnames) {
+               snprintf(buffer, XDR_ADDRBUF_LEN,
+                        NIPQUAD_FMT, NIPQUAD(argp->addr));
+               name = buffer;
+       }
+
+       return xdr_encode_nsm_string(p, name);
+}
+
+/*
+ * The "my_id" argument specifies the hostname and RPC procedure
+ * to be called when the status manager receives notification
+ * (via the SM_NOTIFY call) that the state of host "mon_name"
+ * has changed.
+ */
+static __be32 *xdr_encode_my_id(__be32 *p, struct nsm_args *argp)
+{
+       p = xdr_encode_nsm_string(p, utsname()->nodename);
+       if (!p)
+               return ERR_PTR(-EIO);
+
+       *p++ = htonl(argp->prog);
+       *p++ = htonl(argp->vers);
+       *p++ = htonl(argp->proc);
+
+       return p;
+}
+
+/*
+ * The "mon_id" argument specifies the non-private arguments
+ * of an SM_MON or SM_UNMON call.
+ */
+static __be32 *xdr_encode_mon_id(__be32 *p, struct nsm_args *argp)
+{
+       p = xdr_encode_mon_name(p, argp);
+       if (!p)
+               return ERR_PTR(-EIO);
+
+       return xdr_encode_my_id(p, argp);
+}
+
 static __be32 *
 xdr_encode_common(struct rpc_rqst *rqstp, __be32 *p, struct nsm_args *argp)
 {
@@ -225,16 +292,13 @@ xdr_decode_stat(struct rpc_rqst *rqstp, __be32 *p, struct nsm_res *resp)
 #define SM_monres_sz   2
 #define SM_unmonres_sz 1
 
-#ifndef MAX
-# define MAX(a, b)     (((a) > (b))? (a) : (b))
-#endif
-
 static struct rpc_procinfo     nsm_procedures[] = {
 [SM_MON] = {
                .p_proc         = SM_MON,
                .p_encode       = (kxdrproc_t) xdr_encode_mon,
                .p_decode       = (kxdrproc_t) xdr_decode_stat_res,
-               .p_bufsiz       = MAX(SM_mon_sz, SM_monres_sz) << 2,
+               .p_arglen       = SM_mon_sz,
+               .p_replen       = SM_monres_sz,
                .p_statidx      = SM_MON,
                .p_name         = "MONITOR",
        },
@@ -242,7 +306,8 @@ static struct rpc_procinfo  nsm_procedures[] = {
                .p_proc         = SM_UNMON,
                .p_encode       = (kxdrproc_t) xdr_encode_unmon,
                .p_decode       = (kxdrproc_t) xdr_decode_stat,
-               .p_bufsiz       = MAX(SM_mon_id_sz, SM_unmonres_sz) << 2,
+               .p_arglen       = SM_mon_id_sz,
+               .p_replen       = SM_unmonres_sz,
                .p_statidx      = SM_UNMON,
                .p_name         = "UNMONITOR",
        },