NFS: Refactor nfs_get_client(): initialize nfs_client

Clean up: Continue to rationalize the locking in nfs_get_client() by
moving the logic that handles the case where a matching server IP
address is not found.

When we support server trunking detection, client initialization may
return a different nfs_client struct than was passed to it.  Change
the synopsis of the init_client methods to return an nfs_client.

The client initialization logic in nfs_get_client() is not much more
than a wrapper around ->init_client.  It's simpler to keep the little
bits of error handling in the version-specific init_client methods.

No behavior change is expected.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 46 insertions, 37 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 5f19f9577730..8a4b3c2c5a2b 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -546,7 +546,6 @@ nfs_get_client(const struct nfs_client_initdata *cl_init,
                int noresvport)
 {
         struct nfs_client *clp, *new = NULL;
-        int error;
         struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
 
         dprintk("--> nfs_get_client(%s,v%u)\n",
@@ -563,8 +562,13 @@ nfs_get_client(const struct nfs_client_initdata *cl_init,
                                 nfs_free_client(new);
                         return nfs_found_client(cl_init, clp);
                 }
-                if (new)
-                        goto install_client;
+                if (new) {
+                        list_add(&new->cl_share_link, &nn->nfs_client_list);
+                        spin_unlock(&nn->nfs_client_lock);
+                        return cl_init->rpc_ops->init_client(new,
+                                                timeparms, ip_addr,
+                                                authflavour, noresvport);
+                }
 
                 spin_unlock(&nn->nfs_client_lock);
 
@@ -574,21 +578,6 @@ nfs_get_client(const struct nfs_client_initdata *cl_init,
         dprintk("<-- nfs_get_client() Failed to find %s (%ld)\n",
                 cl_init->hostname ?: "", PTR_ERR(new));
         return new;
-
-        /* install a new client and return with it unready */
-install_client:
-        clp = new;
-        list_add(&clp->cl_share_link, &nn->nfs_client_list);
-        spin_unlock(&nn->nfs_client_lock);
-
-        error = cl_init->rpc_ops->init_client(clp, timeparms, ip_addr,
-                                              authflavour, noresvport);
-        if (error < 0) {
-                nfs_put_client(clp);
-                return ERR_PTR(error);
-        }
-        dprintk("--> nfs_get_client() = %p [new]\n", clp);
-        return clp;
 }
 
 /*
@@ -813,10 +802,19 @@ static int nfs_init_server_rpcclient(struct nfs_server *server,
         return 0;
 }
 
-/*
- * Initialise an NFS2 or NFS3 client
+/**
+ * nfs_init_client - Initialise an NFS2 or NFS3 client
+ *
+ * @clp: nfs_client to initialise
+ * @timeparms: timeout parameters for underlying RPC transport
+ * @ip_addr: IP presentation address (not used)
+ * @authflavor: authentication flavor for underlying RPC transport
+ * @noresvport: set if RPC transport can use an ephemeral source port
+ *
+ * Returns pointer to an NFS client, or an ERR_PTR value.
  */
-int nfs_init_client(struct nfs_client *clp, const struct rpc_timeout *timeparms,
+struct nfs_client *nfs_init_client(struct nfs_client *clp,
+                    const struct rpc_timeout *timeparms,
                     const char *ip_addr, rpc_authflavor_t authflavour,
                     int noresvport)
 {
@@ -825,7 +823,7 @@ int nfs_init_client(struct nfs_client *clp, const struct rpc_timeout *timeparms,
         if (clp->cl_cons_state == NFS_CS_READY) {
                 /* the client is already initialised */
                 dprintk("<-- nfs_init_client() = 0 [already %p]\n", clp);
-                return 0;
+                return clp;
         }
 
         /*
@@ -837,12 +835,13 @@ int nfs_init_client(struct nfs_client *clp, const struct rpc_timeout *timeparms,
         if (error < 0)
                 goto error;
         nfs_mark_client_ready(clp, NFS_CS_READY);
-        return 0;
+        return clp;
 
 error:
         nfs_mark_client_ready(clp, error);
+        nfs_put_client(clp);
         dprintk("<-- nfs_init_client() = xerror %d\n", error);
-        return error;
+        return ERR_PTR(error);
 }
 
 /*
@@ -1358,14 +1357,22 @@ static int nfs4_init_client_minor_version(struct nfs_client *clp)
         return nfs4_init_callback(clp);
 }
 
-/*
- * Initialise an NFS4 client record
+/**
+ * nfs4_init_client - Initialise an NFS4 client record
+ *
+ * @clp: nfs_client to initialise
+ * @timeparms: timeout parameters for underlying RPC transport
+ * @ip_addr: callback IP address in presentation format
+ * @authflavor: authentication flavor for underlying RPC transport
+ * @noresvport: set if RPC transport can use an ephemeral source port
+ *
+ * Returns pointer to an NFS client, or an ERR_PTR value.
  */
-int nfs4_init_client(struct nfs_client *clp,
-                     const struct rpc_timeout *timeparms,
-                     const char *ip_addr,
-                     rpc_authflavor_t authflavour,
-                     int noresvport)
+struct nfs_client *nfs4_init_client(struct nfs_client *clp,
+                                    const struct rpc_timeout *timeparms,
+                                    const char *ip_addr,
+                                    rpc_authflavor_t authflavour,
+                                    int noresvport)
 {
         char buf[INET6_ADDRSTRLEN + 1];
         int error;
@@ -1373,7 +1380,7 @@ int nfs4_init_client(struct nfs_client *clp,
         if (clp->cl_cons_state == NFS_CS_READY) {
                 /* the client is initialised already */
                 dprintk("<-- nfs4_init_client() = 0 [already %p]\n", clp);
-                return 0;
+                return clp;
         }
 
         /* Check NFS protocol revision and initialize RPC op vector */
@@ -1413,12 +1420,13 @@ int nfs4_init_client(struct nfs_client *clp,
 
         if (!nfs4_has_session(clp))
                 nfs_mark_client_ready(clp, NFS_CS_READY);
-        return 0;
+        return clp;
 
 error:
         nfs_mark_client_ready(clp, error);
+        nfs_put_client(clp);
         dprintk("<-- nfs4_init_client() = xerror %d\n", error);
-        return error;
+        return ERR_PTR(error);
 }
 
 /*
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 989959a59f07..3a9e80c9524b 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -238,7 +238,7 @@ extern int nfs4_init_ds_session(struct nfs_client *clp);
 
 /* proc.c */
 void nfs_close_context(struct nfs_open_context *ctx, int is_sync);
-extern int nfs_init_client(struct nfs_client *clp,
+extern struct nfs_client *nfs_init_client(struct nfs_client *clp,
                            const struct rpc_timeout *timeparms,
                            const char *ip_addr, rpc_authflavor_t authflavour,
                            int noresvport);
@@ -373,7 +373,7 @@ void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo,
 
 /* nfs4proc.c */
 extern void __nfs4_read_done_cb(struct nfs_read_data *);
-extern int nfs4_init_client(struct nfs_client *clp,
+extern struct nfs_client *nfs4_init_client(struct nfs_client *clp,
                             const struct rpc_timeout *timeparms,
                             const char *ip_addr,
                             rpc_authflavor_t authflavour,
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index c420b8d60a55..0c521cd496a7 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1397,7 +1397,8 @@ struct nfs_rpc_ops {
                                 struct nfs_open_context *ctx,
                                 int open_flags,
                                 struct iattr *iattr);
-        int     (*init_client) (struct nfs_client *, const struct rpc_timeout *,
+        struct nfs_client *
+                (*init_client) (struct nfs_client *, const struct rpc_timeout *,
                                 const char *, rpc_authflavor_t, int);
 };