From c0c2a8b2df59eeb29ef1b75be5fd3ee26c6b10c3 Mon Sep 17 00:00:00 2001
From: patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>
Date: Thu, 14 Jun 2012 00:47:42 +0000
Subject: [PATCH] NFS just finished a major weight reduction program

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4838 42af7a65-404d-4744-a932-0658087f49c3
---
 Documentation/NuttX.html             |  20 +-
 Documentation/NuttxPortingGuide.html |  79 +++-
 configs/README.txt                   |   5 +
 fs/nfs/Kconfig                       |  18 +-
 fs/nfs/nfs.h                         | 194 +-------
 fs/nfs/nfs_mount.h                   |  41 +-
 fs/nfs/nfs_node.h                    |   6 -
 fs/nfs/nfs_proto.h                   |  28 --
 fs/nfs/nfs_socket.c                  |   8 -
 fs/nfs/nfs_util.c                    | 103 +----
 fs/nfs/nfs_vfsops.c                  | 659 +++++++++++++--------------
 fs/nfs/rpc.h                         |  14 -
 fs/nfs/rpc_clnt.c                    | 280 +-----------
 include/nuttx/fs/nfs.h               |   9 -
 tools/mkconfig.c                     |  12 +-
 15 files changed, 473 insertions(+), 1003 deletions(-)

diff --git a/Documentation/NuttX.html b/Documentation/NuttX.html
index 8a4489ff6f..a3f87f9179 100644
--- a/Documentation/NuttX.html
+++ b/Documentation/NuttX.html
@@ -8,7 +8,7 @@
   <tr align="center" bgcolor="#e4e4e4">
     <td>
       <h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1>
-      <p>Last Updated: June 6, 2012</p>
+      <p>Last Updated: June 13, 2012</p>
     </td>
   </tr>
 </table>
@@ -424,6 +424,15 @@
       </li>
     </p>
 </tr>
+<tr>
+  <td><br></td>
+  <td>
+    <p>
+      <li>
+        NFS Client. Client side support for a Network File System (NFS, version 3, UDP).
+      </li>
+    </p>
+</tr>
 <tr>
   <td><br></td>
   <td>
@@ -561,6 +570,15 @@
       <li>Networking utilities (DHCP server and client, SMTP client, TELNET client, FTP server and client, TFTP client, HTTP server and client).  Inheritable TELNET sessions (as &quot;controlling terminal&quot;)</li>
     </p>
 </tr>
+<tr>
+  <td><br></td>
+  <td>
+    <p>
+      <li>
+        NFS Client. Client side support for a Network File System (NFS, version 3, UDP).
+      </li>
+    </p>
+</tr>
 <tr>
   <td><br></td>
   <td>
diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index 18ff07d19c..ee3c9a5e98 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -12,7 +12,7 @@
       <h1><big><font color="#3c34ec">
         <i>NuttX RTOS Porting Guide</i>
       </font></big></h1>
-      <p>Last Updated: May 6, 2011</p>
+      <p>Last Updated: June 13, 2012</p>
     </td>
   </tr>
 </table>
@@ -634,6 +634,7 @@
 </p>
 <ul><pre>
 <i>&lt;board-name&gt;</i>
+|-- Kconfig
 |-- include/
 |   |-- board.h
 |   `-- <i>(board-specific header files)</i>
@@ -1005,41 +1006,58 @@
 </p>
 <ul><pre>
 drivers/
+|-- Kconfig
 |-- Makefile
 |-- analog/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common ADC and DAC driver source files)</i>
 |-- bch/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(bch driver source files)</i>
 |-- input/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common touchscreen and keypad driver source files)</i>
 |-- lcd/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common LCD driver source files)</i>
 |-- mmcsd/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common MMC/SD card driver source files)</i>
 |-- mtd/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common memory technology device driver source files)</i>
 |-- net/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common network driver source files)</i>
 |-- sensors/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common sensor driver source files)</i>
 |-- serial/
+|   |-- Kconfig
+|   |-- Make.defs
+|   `-- <i>(Files for the Calypso SERCOMM driver)</i>
+|-- serial/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common front-end character drivers for chip-specific UARTs)</i>
 |-- usbdev/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common USB device driver source files)</i>
 |-- usbhost/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common USB host driver source files)</i>
 |-- wirelss/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(Common wireless driver source files)</i>
 `-- <i>(Various common driver source files)</i>
@@ -1053,17 +1071,26 @@ drivers/
 </p>
 <ul><pre>
 fs/
+|-- Kconfig
 |-- Makefile
 |-- fat/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(FAT file system source files)</i>
 |-- mmap/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(RAM-based file mapping source files)</i>
+|-- nfs/
+|   |-- Kconfig
+|   |-- Make.defs
+|   `-- <i>(NFS client file system source files)</i>
 |-- nxffs/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(NuttX Flash File System (NXFFS) source files)</i>
 |-- romfs/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(ROMFS file system source files)</i>
  `-- <i>(common file system source files)</i>
@@ -1076,6 +1103,7 @@ fs/
 </p>
 <ul><pre>
 graphics/
+|-- Kconfig
 |-- Makefile
 |-- nxbe/
 |   |-- Make.defs
@@ -1255,37 +1283,60 @@ tools/
 </p>
 <ul><pre>
 netutils/
+|-- Kconfig
 |-- Makefile
-|-- dhcp/
+|-- dhcdp/
+|   |-- Kconfig
 |   |-- Make.defs
-|   `-- <i>(dhcp source files)</i>
+|   `-- <i>(DHCP client source files)</i>
 |-- dhcpd/
+|   |-- Kconfig
 |   |-- Make.defs
-|   `-- <i>(dhcpd source files)</i>
+|   `-- <i>(DHCP server source files)</i>
+|-- ftpc/
+|   |-- Kconfig
+|   |-- Make.defs
+|   `-- <i>(FTP client source files)</i>
+|-- ftpd/
+|   |-- Kconfig
+|   |-- Make.defs
+|   `-- <i>(FTP server source files)</i>
 |-- resolv/
+|   |-- Kconfig
+|   |-- Make.defs
+|   `-- <i>(resolv source files)</i>
+|-- resolv/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(resolv source files)</i>
 |-- smtp/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(smtp source files)</i>
 |-- telnetd/
+|   |-- Kconfig
 |   |-- Make.defs
-|   `-- <i>(telnetd source files)</i>
+|   `-- <i>(Telnet client source files)</i>
 |-- tftpc/
+|   |-- Kconfig
 |   |-- Make.defs
-|   `-- <i>(tftpc source files)</i>
+|   `-- <i>(TFTP client source files)</i>
 |-- thttpd/
+|   |-- Kconfig
 |   |-- Make.defs
-|   `-- <i>(thttpd source files)</i>
+|   `-- <i>(thttpd HTTP server source files)</i>
 |-- uiplib/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(uiplib source files)</i>
 |-- weblclient/
+|   |-- Kconfig
 |   |-- Make.defs
 |   `-- <i>(webclient source files)</i>
 |-- webserver/
+|   |-- Kconfig
 |   |-- Make.defs
-|   `-- <i>(webserver source files)</i>
+|   `-- <i>(uIP webserver source files)</i>
 `-- <i>(netutils common files)</i>
 </pre></ul>
 
@@ -2262,8 +2313,9 @@ extern void up_ledoff(int led);
   NuttX supports the standard <code>mount()</code> command that allows
   a block driver to be bound to a mountpoint within the pseudo file system
   and to a file system.
-  At present, NuttX supports the standard VFAT and ROMFS file systems and
-  well as a special, wear-leveling NuttX FLASH File System (NXFFS).
+  At present, NuttX supports the standard VFAT and ROMFS file systems,
+  a special, wear-leveling NuttX FLASH File System (NXFFS),
+  as well as a Network File System client (NFS version 3, UDP).
 </p>
 
 <p><b>Comparison to Linux</b>
@@ -4437,6 +4489,13 @@ build
   <li>
     <code>CONFIG_FS_ROMFS</code>: Enable ROMFS file system support
   </li>
+  <li>
+    <code>CONFIG_NFS</code>: Enable Network File System (NFS) client file system support.
+    Provided support is version 3 using UDP.
+    In addition to common prerequisites for mount-able file systems in general,
+    this option requires UDP networking support;
+    this would include <code>CONFIG_NET</code> and <code>CONFIG_NET_UDP</code> at a minimum.
+  </li>
   <li>
     <code>CONFIG_FS_RAMMAP</code>: For file systems that do not support
     XIP, this option will enable a limited form of memory mapping that is
diff --git a/configs/README.txt b/configs/README.txt
index 56659fe36f..692c7792e7 100644
--- a/configs/README.txt
+++ b/configs/README.txt
@@ -647,6 +647,11 @@ defconfig -- This is a configuration file similar to the Linux
       and making it available for re-use (and possible over-wear).
       Default: 8192.
     CONFIG_FS_ROMFS - Enable ROMFS filesystem support
+    CONFIG_NFS - Enable Network File System (NFS) client file system support.
+      Provided support is version 3 using UDP.  In addition to common
+      prerequisites for mount-able file systems in general, this option
+      requires UDP networking support; this would include CONFIG_NETand
+      CONFIG_NET_UDP at a minimum.
     CONFIG_FS_RAMMAP - For file systems that do not support XIP, this
       option will enable a limited form of memory mapping that is
       implemented by copying whole files into memory.
diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index 841b1ab8ee..3838efffa6 100644
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -12,19 +12,13 @@ config NFS
 
 #if NFS
 
-config NFS_TCPIP
-	bool "TCP/IP RPC support"
+config NFS_STATISTICS
+	bool "NFS Stastics"
 	default n
 	depends on NFS
 	---help---
-		By default, NFS uses a UDP RPC protocol.  Enable this option to
-		build in support for a TCP/IP-based RPC.
+		Collect support for NFS statistics.  There is no user interface to
+		obtain these statistics, however.  So they would only be of value
+		if you add debug instrumentation or use a debugger.
 
-config NFS_UNIX_AUTH
-	bool "NFS Unix authentication"
-	default n
-	depends on NFS
-	---help---
-		Build in support for Unix-style authentication.
-
-#endif
\ No newline at end of file
+#endif
diff --git a/fs/nfs/nfs.h b/fs/nfs/nfs.h
index 0fe30f5f03..b35ef2c8d1 100644
--- a/fs/nfs/nfs.h
+++ b/fs/nfs/nfs.h
@@ -54,19 +54,25 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
-#define NFS_TICKINTVL      5             /* Desired time for a tick (msec) */
-#define NFS_HZ             (CLOCKS_PER_SEC / nfs_ticks)  /* Ticks/sec */
+#if MSEC_PER_TICK <= 5 
+#  define NFS_TICKINTVL    5             /* Desired time for a tick (msec) */
+#  define NFS_TICKS        (CLOCKS_PER_SEC * NFS_TICKINTVL + 500) / 1000
+#  define NFS_HZ           (CLOCKS_PER_SEC / NFS_TICKS)  /* Ticks/sec */
+#else
+#  define NFS_TICKINTVL    MSEC_PER_TICK /* Smallest that we can get */
+#  define NFS_TICKS        1             /* Number of system ticks */
+#  define NFS_HZ           CLOCKS_PER_SEC /* Ticks/sec */
+#endif
+
 #define NFS_TIMEO          (1 * NFS_HZ)  /* Default timeout = 1 second */
 #define NFS_MINTIMEO       (1 * NFS_HZ)  /* Min timeout to use */
 #define NFS_MAXTIMEO       (60 * NFS_HZ) /* Max timeout to backoff to */
-#define NFS_MINIDEMTIMEO   (5 * NFS_HZ)  /* Min timeout for non-idempotent ops */
 #define NFS_TIMEOUTMUL     2             /* Timeout/Delay multiplier */
 #define NFS_MAXREXMIT      100           /* Stop counting after this many */
 #define NFS_RETRANS        10            /* Num of retrans for soft mounts */
 #define NFS_WSIZE          8192          /* Def. write data size <= 8192 */
 #define NFS_RSIZE          8192          /* Def. read data size <= 8192 */
 #define NFS_READDIRSIZE    8192          /* Def. readdir size */
-#define NFS_MAXASYNCDAEMON 20            /* Max. number async_daemons runable */
 #define NFS_NPROCS         23
 
 /* Ideally, NFS_DIRBLKSIZ should be bigger, but I've seen servers with
@@ -74,85 +80,6 @@
  */
 
 #define NFS_DIRBLKSIZ      1024          /* Must be a multiple of DIRBLKSIZ */
-#define NFS_READDIRBLKSIZ  512           /* Size of read dir blocks. XXX */
-
-/* Oddballs */
-
-#define NFS_CMPFH(n, f, s) \
-    ((n)->n_fhsize == (s) && !bcmp((void *)(n)->n_fhp, (void *)(f), (s)))
-#define NFS_ISV3(i)     (VFSTONFS((i)->f_inode)->nm_flag & NFSMNT_NFSV3)
-#define NFS_SRVMAXDATA(n) \
-    (((n)->nd_flag & ND_NFSV3) ? (((n)->nd_nam2) ? \
-    NFS_MAXDGRAMDATA : NFS_MAXDATA) : NFS_V2MAXDATA)
-
-/* sys/malloc.h needs M_NFSDIROFF, M_NFSRVDESC and M_NFSBIGFH added. */
-
-#ifndef M_NFSRVDESC
-#  define M_NFSRVDESC     M_TEMP
-#endif
-#ifndef M_NFSDIROFF
-#  define M_NFSDIROFF     M_TEMP
-#endif
-#ifndef M_NFSBIGFH
-#  define M_NFSBIGFH      M_TEMP
-#endif
-
-/*The B_INVAFTERWRITE flag should be set to whatever is required by the
- * buffer cache code to say "Invalidate the block after it is written back".
- */
-
-#define B_INVAFTERWRITE   B_INVAL
-
-/* Flags for nfssvc() system call. */
-
-#define NFSSVC_BIOD       0x002
-#define NFSSVC_NFSD       0x004
-#define NFSSVC_ADDSOCK    0x008
-#define NFSSVC_AUTHIN     0x010
-#define NFSSVC_GOTAUTH    0x040
-#define NFSSVC_AUTHINFAIL 0x080
-#define NFSSVC_MNTD       0x100
-
-/* On fast networks, the estimator will try to reduce the timeout lower than
- * the latency of the server's disks, which results in too many timeouts, so
- * cap the lower bound.
- */
-
-#define NFS_MINRTO      (NFS_HZ >> 2)
-
-/* Keep the RTO from increasing to unreasonably large values when a server is
- * not responding.
- */
-
-#define NFS_MAXRTO      (20 * NFS_HZ)
-
-#define NFS_MAX_TIMER   (NFS_WRITE_TIMER)
-#define NFS_INITRTT     (NFS_HZ << 3)
-
-/* Bits for "ns_flag" */
-
-#define SLP_VALID       0x01 /* connection is usable */
-#define SLP_DOREC       0x02 /* receive operation required */
-#define SLP_NEEDQ       0x04 /* connection has data to queue from socket */
-#define SLP_DISCONN     0x08 /* connection is closed */
-#define SLP_GETSTREAM   0x10 /* extracting RPC from TCP connection */
-#define SLP_LASTFRAG    0x20 /* last fragment received on TCP connection */
-#define SLP_ALLFLAGS    0xff /* convenience */
-
-#define SLP_INIT        0x01 /* NFS data undergoing initialization */
-#define SLP_WANTINIT    0x02 /* thread waiting on NFS initialization */
-
-/* Bits for "nfsd_flag" */
-
-#define NFSD_WAITING    0x01
-#define NFSD_REQINPROG  0x02
-#define NFSD_NEEDAUTH   0x04
-#define NFSD_AUTHFAIL   0x08
-
-/* Bits for "nd_flag" */
-
-#define ND_NFSV3        0x08
-#define NFSD_CHECKSLP   0x01
 
 /* Increment NFS statistics */
 
@@ -172,111 +99,12 @@ extern uint32_t nfs_xdrneg1;
 #ifdef CONFIG_NFS_STATISTICS
 extern struct nfsstats nfsstats;
 #endif
-extern int nfs_ticks;
 
 /****************************************************************************
  * Public Types
  ****************************************************************************/
 
-#undef COMP
-#ifdef COMP
-/* Structures for the nfssvc(2) syscall.
- * Not that anyone besides nfsd(8) should ever use it.
- */
-
-struct nfsd_args
-{
-  int sock;                   /* Socket to serve */
-  void *name;                 /* Client addr for connection based sockets */
-  int namelen;                /* Length of name */
-};
-
-struct nfsd_srvargs
-{
-  struct nfsd *nsd_nfsd;        /* Pointer to in kernel nfsd struct */
-  uid_t nsd_uid;                /* Effective uid mapped to cred */
-  uint32_t nsd_haddr;           /* IP address of client */
-  int nsd_authlen;              /* Length of auth string (ret) */
-  uint8_t *nsd_authstr;         /* Auth string (ret) */
-  int nsd_verflen;              /* and the verifier */
-  uint8_t *nsd_verfstr;
-  struct timeval nsd_timestamp; /* timestamp from verifier */
-  uint32_t nsd_ttl;             /* credential ttl (sec) */
-};
-
-/* The set of signals the interrupt an I/O in progress for NFSMNT_INT mounts.
- * What should be in this set is open to debate, but I believe that since
- * I/O system calls on ufs are never interrupted by signals the set should
- * be minimal. My reasoning is that many current programs that use signals
- * such as SIGALRM will not expect file I/O system calls to be interrupted
- * by them and break.
- */
-
-/* Nfs outstanding request list element */
-
-struct nfsreq
-{
-  dq_entry_t r_chain;
-  struct nfsmount *r_nmp;
-  uint32_t r_xid;
-  int r_flags;                /* flags on request, see below */
-  int r_rexmit;               /* current retrans count */
-  int r_timer;                /* tick counter on reply */
-  int r_procnum;              /* NFS procedure number */
-  int r_rtt;                  /* RTT for rpc */
-};
-
-enum nfs_rto_timers
-{
-  NFS_DEFAULT_TIMER,
-  NFS_GETATTR_TIMER,
-  NFS_LOOKUP_TIMER,
-  NFS_READ_TIMER,
-  NFS_WRITE_TIMER,
-};
-
-/* Network address hash list element */
-
-union nethostaddr
-{
-  uint32_t had_inetaddr;
-  struct mbuf *had_nam;
-};
-
-struct nfssvc_sock
-{
- // TAILQ_ENTRY(nfssvc_sock) ns_chain;  /* List of all nfssvc_sock's */
-  struct file *ns_fp;         /* fp from the... */
-  struct socket *ns_so;       /* ...socket this struct wraps */
-  int ns_flag;                /* socket status flags */
-  int ns_solock;              /* lock for connected socket */
-  int ns_cc;                  /* actual chars queued */
-  int ns_reclen;              /* length of first queued record */
-  uint32_t ns_sref;           /* # of refs to this struct */
-};
-
-/* One of these structures is allocated for each nfsd. */
-
-struct nfsd
-{
-  //TAILQ_ENTRY(nfsd) nfsd_chain;  /* List of all nfsd's */
-  int nfsd_flag;                   /* NFSD_ flags */
-  struct nfssvc_sock *nfsd_slp;    /* Current socket */
-  struct nfsrv_descript *nfsd_nd;  /* Associated nfsrv_descript */
-};
-
-/* This structure is used by the server for describing each request. */
-
-struct nfsrv_descript
-{
-  unsigned int nd_procnum;    /* RPC # */
-  int nd_flag;                /* nd_flag */
-  int nd_repstat;             /* Reply status */
-  uint32_t nd_retxid;         /* Reply xid */
-};
-#endif
-
-/* Stats structure */
+/* NFS statistics structure */
 
 struct nfsstats
 {
diff --git a/fs/nfs/nfs_mount.h b/fs/nfs/nfs_mount.h
index 66343f90eb..d3be1a5982 100644
--- a/fs/nfs/nfs_mount.h
+++ b/fs/nfs/nfs_mount.h
@@ -51,7 +51,7 @@
 #include <sys/socket.h>
 
 #include "rpc.h"
- 
+
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
@@ -78,17 +78,17 @@ struct nfsmount
   uint8_t          nm_flag;                   /* Flags for soft/hard... */
   uint8_t          nm_fhsize;                 /* Size of root file handle (host order) */
   uint8_t          nm_sotype;                 /* Type of socket */
-  uint8_t          nm_soproto;                /* and protocol */
   uint8_t          nm_timeo;                  /* Init timer for NFSMNT_DUMBTIMR */
   uint8_t          nm_retry;                  /* Max retries */
   uint16_t         nm_rsize;                  /* Max size of read RPC */
   uint16_t         nm_wsize;                  /* Max size of write RPC */
   uint16_t         nm_readdirsize;            /* Size of a readdir RPC */
   uint8_t          nm_verf[NFSX_V3WRITEVERF]; /* V3 write verifier */
+  uint16_t         nm_buflen;                 /* Size of I/O buffer */
 
   /* Set aside memory on the stack to hold the largest call message.  NOTE
-   * that for the case of the write call message, the reply message is in
-   * this union.
+   * that for the case of the write call message, it is the reply message that
+   * is in this union.
    */
 
   union
@@ -105,7 +105,38 @@ struct nfsmount
     struct rpc_call_readdir readdir;
     struct rpc_call_fs      fs;
     struct rpc_reply_write  write;
-  } nm_smallbuffer;
+  } nm_msgbuffer;
+
+  /* I/O buffer (must be a aligned to 32-bit boundaries).  This buffer used for all
+   * reply messages EXCEPT for the WRITE RPC. In that case it is used for the WRITE
+   * call message that contains the data to be written.  This buffer must be
+   * dynamically sized based on the characteristics of the server and upon the
+   * configuration of the NuttX network.  It must be sized to hold the largest
+   * possible WRITE call message or READ response message.
+   */
+
+  uint32_t         nm_iobuffer[1];            /* Actual size is given by nm_buflen */
+};
+
+/* The size of the nfsmount structure will debug on the size of the allocated I/O
+ * buffer.
+ */
+
+#define SIZEOF_nfsmount(n) (sizeof(struct nfsmount) + ((n + 3) & ~3) - sizeof(uint32_t))
+
+/* Mount parameters structure. This structure is use in nfs_decode_args funtion before one
+ * mount structure is allocated in each NFS mount.
+ */
+
+struct nfs_mount_parameters
+{
+
+  uint8_t          flag;                   /* Flags for soft/hard... */
+  uint8_t          timeo;                  /* Init timer for NFSMNT_DUMBTIMR */
+  uint8_t          retry;                  /* Max retries */
+  uint16_t         rsize;                  /* Max size of read RPC */
+  uint16_t         wsize;                  /* Max size of write RPC */
+  uint16_t         readdirsize;            /* Size of a readdir RPC */
 };
 
 #endif
diff --git a/fs/nfs/nfs_node.h b/fs/nfs/nfs_node.h
index 02e14cbde8..4ae9e162c2 100644
--- a/fs/nfs/nfs_node.h
+++ b/fs/nfs/nfs_node.h
@@ -73,16 +73,10 @@ struct nfsnode
   uint8_t            n_type;        /* File type */
   uint8_t            n_fhsize;      /* Size in bytes of the file handle */
   uint8_t            n_flags;       /* Node flags */
-  uint16_t           n_buflen;      /* Size of I/O buffer */
   struct timespec    n_mtime;       /* File modification time (see NOTE) */
   time_t             n_ctime;       /* File creation time (see NOTE) */
   nfsfh_t            n_fhandle;     /* NFS File Handle */
   uint64_t           n_size;        /* Current size of file (see NOTE) */
-
-  /* I/O buffer (must be a aligned to 32-bit boundaries) */
-
-  uint8_t            n_iobuffer[1]; /* Actual size is given by n_buflen */
 };
-#define SIZEOF_nfsnode(n) (sizeof(struct nfsnode) + ((n)-1))
 
 #endif /* __FS_NFS_NFS_NODE_H */
diff --git a/fs/nfs/nfs_proto.h b/fs/nfs/nfs_proto.h
index 245f3e189f..645b6bdf0e 100644
--- a/fs/nfs/nfs_proto.h
+++ b/fs/nfs/nfs_proto.h
@@ -296,34 +296,6 @@ typedef enum
   NFFIFO = 7                   /* Named FIFO */
 } nfstype;
 
-#if 0
-typedef struct
-{
-  int32_t val[2];
-} fsid_t;                      /* file system id type */
-
-/* File identifier.
- * These are unique per filesystem on a single machine.
- */
-
-struct fid
-{
-  unsigned short fid_len;      /* length of data in bytes */
-  unsigned short fid_reserved; /* force longword alignment */
-  char fid_data[MAXFIDSZ];     /* data (variable length) */
-};
-
-/* Generic file handle */
-
-struct fhandle
-{
-  fsid_t fh_fsid;              /* File system id of mount point */
-  struct fid fh_fid;           /* File sys specific id */
-};
-
-typedef struct fhandle fhandle_t;
-#endif
-
 /* File Handle variable is up to 64 bytes for version 3. This structures a 
  * ariable sized and are provided only for setting aside maximum memory
  * allocations for a file handle.
diff --git a/fs/nfs/nfs_socket.c b/fs/nfs/nfs_socket.c
index d429e68523..c5fe9f1e45 100644
--- a/fs/nfs/nfs_socket.c
+++ b/fs/nfs/nfs_socket.c
@@ -80,7 +80,6 @@
 uint32_t nfs_true;
 uint32_t nfs_false;
 uint32_t nfs_xdrneg1;
-int nfs_ticks;
 struct nfsstats nfsstats;
 
 /****************************************************************************
@@ -97,12 +96,6 @@ void nfs_init(void)
    nfs_false = txdr_unsigned(FALSE);
    nfs_xdrneg1 = txdr_unsigned(-1);
 
-   nfs_ticks = (CLOCKS_PER_SEC * NFS_TICKINTVL + 500) / 1000;
-   if (nfs_ticks < 1)
-    {
-      nfs_ticks = 1;
-    }
-
    rpcclnt_init();
 }
 
@@ -131,7 +124,6 @@ int nfs_connect(struct nfsmount *nmp)
   rpc->rc_path       = nmp->nm_path;
   rpc->rc_name       = &nmp->nm_nam;
   rpc->rc_sotype     = nmp->nm_sotype;
-  rpc->rc_soproto    = nmp->nm_soproto;
 
   nmp->nm_rpcclnt    = rpc;
 
diff --git a/fs/nfs/nfs_util.c b/fs/nfs/nfs_util.c
index 2dd7613df0..643117e22a 100644
--- a/fs/nfs/nfs_util.c
+++ b/fs/nfs/nfs_util.c
@@ -196,102 +196,6 @@ int nfs_checkmount(struct nfsmount *nmp)
   return 0;
 }
 
-/****************************************************************************
- * Name: nfs_fsinfo
- *
- * Description:
- *   Return information about root directory.
- *
- * Returned Value:
- *   0 on success; positive errno value on failure
- *
- * Assumptions:
- *   The caller has exclusive access to the NFS mount structure
- *
- ****************************************************************************/
-
-int nfs_fsinfo(FAR struct nfsmount *nmp)
-{
-  struct rpc_call_fs fsinfo;
-  struct rpc_reply_fsinfo fsp;
-  uint32_t pref;
-  uint32_t max;
-  int error = 0;
-
-  memset(&fsinfo, 0, sizeof(struct rpc_call_fs));
-  memset(&fsp,    0, sizeof(struct rpc_reply_fsinfo));
-
-  fsinfo.fs.fsroot.length = txdr_unsigned(nmp->nm_fhsize);
-  fsinfo.fs.fsroot.handle = nmp->nm_fh;
-
-  /* Request FSINFO from the server */
-
-  nfs_statistics(NFSPROC_FSINFO);
-  error = nfs_request(nmp, NFSPROC_FSINFO,
-                      (FAR const void *)&fsinfo, sizeof(struct FS3args),
-                      (FAR void *)&fsp, sizeof(struct rpc_reply_fsinfo));
-  if (error)
-    {
-      return error;
-    }
-
-  /* Save the root file system attributes */
-#if 0
-  memcpy(&nmp->nm_fattr. &fsp.obj_attributes, sizeof(struct nfs_fattr));
-#endif
-
-  pref = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_wtpref);
-  if (pref < nmp->nm_wsize)
-    {
-      nmp->nm_wsize = (pref + NFS_FABLKSIZE - 1) & ~(NFS_FABLKSIZE - 1);
-    }
-
-  max = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_wtmax);
-  if (max < nmp->nm_wsize)
-    {
-      nmp->nm_wsize = max & ~(NFS_FABLKSIZE - 1);
-      if (nmp->nm_wsize == 0)
-        {
-          nmp->nm_wsize = max;
-        }
-    }
-
-  pref = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_rtpref);
-  if (pref < nmp->nm_rsize)
-    {
-      nmp->nm_rsize = (pref + NFS_FABLKSIZE - 1) & ~(NFS_FABLKSIZE - 1);
-    }
-
-  max = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_rtmax);
-  if (max < nmp->nm_rsize)
-    {
-      nmp->nm_rsize = max & ~(NFS_FABLKSIZE - 1);
-      if (nmp->nm_rsize == 0)
-        {
-          nmp->nm_rsize = max;
-        }
-    }
-
-  pref = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_dtpref);
-  if (pref < nmp->nm_readdirsize)
-    {
-      nmp->nm_readdirsize = (pref + NFS_DIRBLKSIZ - 1) & ~(NFS_DIRBLKSIZ - 1);
-    }
-
-  if (max < nmp->nm_readdirsize)
-    {
-      nmp->nm_readdirsize = max & ~(NFS_DIRBLKSIZ - 1);
-      if (nmp->nm_readdirsize == 0)
-        {
-          nmp->nm_readdirsize = max;
-        }
-    }
-
-  nmp->nm_flag |= NFSMNT_GOTFSINFO;
-
-  return 0;
-}
-
 /****************************************************************************
  * Name: nfs_lookup
  *
@@ -321,11 +225,6 @@ int nfs_lookup(struct nfsmount *nmp, FAR const char *filename,
 
   DEBUGASSERT(nmp && filename && fhandle);
 
-  /* Set all of the buffers to a known state */
-
-  memset(&request,  0, sizeof(struct rpc_call_lookup));
-  memset(&response, 0, sizeof(struct rpc_reply_lookup));
-
   /* Get the length of the string to be sent */
 
   namelen = strlen(filename);
@@ -361,7 +260,7 @@ int nfs_lookup(struct nfsmount *nmp, FAR const char *filename,
 
   nfs_statistics(NFSPROC_LOOKUP);
   error = nfs_request(nmp, NFSPROC_LOOKUP,
-                      (FAR const void *)&request, reqlen,
+                      (FAR void *)&request, reqlen,
                       (FAR void *)&response, sizeof(struct rpc_reply_lookup));
   if (error)
     {
diff --git a/fs/nfs/nfs_vfsops.c b/fs/nfs/nfs_vfsops.c
index c030422ca1..cd8a5ab7a0 100644
--- a/fs/nfs/nfs_vfsops.c
+++ b/fs/nfs/nfs_vfsops.c
@@ -87,10 +87,7 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
-#define NFS_DIRHDSIZ         (sizeof (struct nfs_dirent) - (MAXNAMLEN + 1))
-#define NFS_DIRENT_OVERHEAD  offsetof(struct nfs_dirent, dirent)
-
-/* The V3 EXCLUSIVE file creation logic is not fully support. */
+/* The V3 EXCLUSIVE file creation logic is not fully supported. */
 
 #define USE_GUARDED_CREATE    1
 
@@ -110,12 +107,6 @@
  * Private Type Definitions
  ****************************************************************************/
 
-struct nfs_dirent
-{
-  uint32_t cookie[2];
-  struct dirent dirent;
-};
-
 /****************************************************************************
  * Private Function Prototypes
  ****************************************************************************/
@@ -126,6 +117,7 @@ static int     nfs_fileopen(FAR struct nfsmount *nmp, struct nfsnode *np,
                    FAR const char *relpath, int oflags, mode_t mode);
 static int     nfs_open(FAR struct file *filep, const char *relpath,
                    int oflags, mode_t mode);
+static int     nfs_close(FAR struct file *filep);
 static ssize_t nfs_read(FAR struct file *filep, char *buffer, size_t buflen);
 static ssize_t nfs_write(FAR struct file *filep, const char *buffer,
                    size_t buflen);
@@ -153,7 +145,7 @@ static int     nfs_stat(struct inode *mountpt, const char *relpath,
 const struct mountpt_operations nfs_operations =
 {
   nfs_open,                     /* open */
-  NULL,                         /* close */
+  nfs_close,                    /* close */
   nfs_read,                     /* read */
   nfs_write,                    /* write */
   NULL,                         /* seek */
@@ -220,7 +212,7 @@ static int nfs_filecreate(FAR struct nfsmount *nmp, struct nfsnode *np,
 
   /* Create the CREATE RPC call arguments */
 
-  ptr    = (FAR uint32_t *)&((FAR struct rpc_call_create *)np->n_iobuffer)->create;
+  ptr    = (FAR uint32_t *)&((FAR struct rpc_call_create *)nmp->nm_iobuffer)->create;
   reqlen = 0;
 
   /* Copy the variable length, directory file handle */
@@ -285,13 +277,13 @@ static int nfs_filecreate(FAR struct nfsmount *nmp, struct nfsnode *np,
       *ptr++  = nfs_true;             /* True: Uid value follows */
       *ptr++  = 0;                    /* UID = 0 (nobody) */
       reqlen += 2*sizeof(uint32_t);
-  
+
       /* Set the group ID to one */
 
       *ptr++  = nfs_true;            /* True: Gid value follows */
       *ptr++  = HTONL(1);            /* GID = 1 (nogroup) */
       reqlen += 2*sizeof(uint32_t);
-  
+
       /* Set the size to zero */
 
       *ptr++  = nfs_true;            /* True: Size value follows */
@@ -314,7 +306,7 @@ static int nfs_filecreate(FAR struct nfsmount *nmp, struct nfsnode *np,
     {
       nfs_statistics(NFSPROC_CREATE);
       error = nfs_request(nmp, NFSPROC_CREATE,
-                          (FAR void *)np->n_iobuffer, reqlen,
+                          (FAR void *)nmp->nm_iobuffer, reqlen,
                           (FAR void *)&resok, sizeof(struct rpc_reply_create));
     }
 #ifdef USE_GUARDED_CREATE
@@ -347,7 +339,7 @@ static int nfs_filecreate(FAR struct nfsmount *nmp, struct nfsnode *np,
       np->n_fhsize      = (uint8_t)tmp;
       memcpy(&np->n_fhandle, ptr, tmp);
       ptr += uint32_increment(tmp);
-      
+
       /* Save the attributes in the file data structure */
 
       tmp = *ptr++;  /* handle_follows */
@@ -480,11 +472,8 @@ static int nfs_fileopen(FAR struct nfsmount *nmp, struct nfsnode *np,
 static int nfs_open(FAR struct file *filep, FAR const char *relpath,
                     int oflags, mode_t mode)
 {
-  struct inode      *in;
   struct nfsmount   *nmp;
-  struct nfsnode    *np;
-  uint32_t           buflen;
-  uint32_t           tmp;
+  struct nfsnode    *np = NULL;
   int                error;
 
   /* Sanity checks */
@@ -495,54 +484,18 @@ static int nfs_open(FAR struct file *filep, FAR const char *relpath,
    * mountpoint private data from the inode structure
    */
 
-  in  = filep->f_inode;
-  nmp = (struct nfsmount*)in->i_private;
-
+  nmp = (struct nfsmount*)filep->f_inode->i_private;
   DEBUGASSERT(nmp != NULL);
 
-  /* Determine the size of a buffer that will hold one RPC data transfer */
-
-  {
-     /* Get the maximum size of a read and a write transfer */
- 
-     buflen = SIZEOF_rpc_call_write(nmp->nm_wsize);
-     tmp    = SIZEOF_rpc_reply_read(nmp->nm_rsize);
-
-     /* The buffer size will be the maximum of those two sizes */
-
-     if (tmp > buflen)
-       {
-         buflen = tmp;
-       }
-
-     /* But don't let the buffer size exceed the MSS of the socket type */
-
-#ifdef CONFIG_NFS_TCPIP
-     if (buflen > UIP_TCP_MSS)
-       {
-         buflen = UIP_TCP_MSS;
-       }
-#else
-     if (buflen > UIP_UDP_MSS)
-       {
-         buflen = UIP_UDP_MSS;
-       }
-#endif
-  }
-
   /* Pre-allocate the file private data to describe the opened file. */
 
-  np = (struct nfsnode *)kzalloc(SIZEOF_nfsnode(buflen));
+  np = (struct nfsnode *)kzalloc(sizeof(struct nfsnode));
   if (!np)
     {
       fdbg("ERROR: Failed to allocate private data\n");
       return -ENOMEM;
     }
 
-  /* Save the allocated I/O buffer size */
-
-  np->n_buflen = (uint16_t)buflen;
-
   /* Check if the mount is still healthy */
 
   nfs_semtake(nmp);
@@ -582,10 +535,10 @@ static int nfs_open(FAR struct file *filep, FAR const char *relpath,
            */
 
           fdbg("ERROR: File does not exist\n");
-           error = ENOENT; 
+           error = ENOENT;
           goto errout_with_semaphore;
         }
- 
+
       /* Create the file */
 
       error = nfs_filecreate(nmp, np, relpath, mode);
@@ -604,64 +557,99 @@ static int nfs_open(FAR struct file *filep, FAR const char *relpath,
 
   filep->f_priv = np;
 
-  /* Then insert the new instance into the mountpoint structure.
-   * It needs to be there (1) to handle error conditions that effect
-   * all files, and (2) to inform the umount logic that we are busy
-   * (but a simple reference count could have done that).
+  /* Then insert the new instance at the head of the list in the mountpoint
+   * tructure. It needs to be there (1) to handle error conditions that effect
+   * all files, and (2) to inform the umount logic that we are busy.  We
+   * cannot unmount the file system if this list is not empty!
    */
 
   np->n_next   = nmp->nm_head;
-  np->n_flags |= (NFSNODE_OPEN | NFSNODE_MODIFIED);
-  nmp->nm_head = np->n_next;
+  nmp->nm_head = np;
 
+  np->n_flags |= (NFSNODE_OPEN | NFSNODE_MODIFIED);
   nfs_semgive(nmp);
   return OK;
 
 errout_with_semaphore:
-  kfree(np);
+  if (np)
+    {
+      kfree(np);
+    }
   nfs_semgive(nmp);
   return -error;
 }
 
-#undef COMP
-#ifdef COMP
 /****************************************************************************
  * Name: nfs_close
  *
+ * Description:
+ *   Close a file.
+ *
  * Returned Value:
  *   0 on success; a negated errno value on failure.
  *
  ****************************************************************************/
 
-static int nfs_close(FAR struct file *filep) done
+static int nfs_close(FAR struct file *filep)
 {
-  struct nfsmount *nmp;
-  struct nfsnode *np;
-  int error = 0;
-
-  fvdbg("Closing\n");
+  FAR struct nfsmount *nmp;
+  FAR struct nfsnode  *np;
+  FAR struct nfsnode  *prev;
+  FAR struct nfsnode  *curr;
+  int                  error;
 
   /* Sanity checks */
 
-  DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL);
+  DEBUGASSERT(filep->f_inode != NULL);
 
-  /* Recover our private data from the struct file instance */
-
-  np = filep->f_priv;
-  nmp = filep->f_inode->i_private;
+  /* Get the mountpoint inode reference from the file structure and the
+   * mountpoint private data from the inode structure
+   */
 
+  nmp = (struct nfsmount*)filep->f_inode->i_private;
   DEBUGASSERT(nmp != NULL);
 
-  if (np->n_type == NFREG)
-    {
-      error = nfs_sync(filep);
-      kfree(np);
-      filep->f_priv = NULL;
-    }
+  /* Get exclusive access to the mount structure. */
 
-  return -error;
+  nfs_semtake(nmp);
+
+  /* Find our file structure in the list of file structures containted in the
+   * mount structure.
+   */
+
+ error = EINVAL;
+ for (prev = NULL, curr = nmp->nm_head; curr; prev = curr, curr = curr->n_next)
+   {
+     /* Check if this node is ours */
+
+     if (np == curr)
+       {
+         /* Yes.. remove it from the list of file structures */
+
+         if (prev)
+           {
+             /* Remove from mid-list */
+
+             prev->n_next = np->n_next;
+           }
+         else
+           {
+             /* Remove from the head of the list */
+
+             nmp->nm_head = np->n_next;
+           }
+
+         /* Then deallocate the file structure and return success */
+
+         kfree(np);
+         error = OK;
+         break;
+       }
+   }
+
+  nfs_semgive(nmp);
+  return error;
 }
-#endif
 
 /****************************************************************************
  * Name: nfs_read
@@ -680,7 +668,6 @@ static ssize_t nfs_read(FAR struct file *filep, char *buffer, size_t buflen)
   ssize_t                    tmp;
   ssize_t                    bytesread;
   size_t                     reqlen;
-  struct rpc_call_read       request;
   FAR uint32_t              *ptr;
   int                        error = 0;
 
@@ -723,7 +710,7 @@ static ssize_t nfs_read(FAR struct file *filep, char *buffer, size_t buflen)
   for (bytesread = 0; bytesread < buflen; )
     {
       /* Make sure that the attempted read size does not exceed the RPC maximum */
- 
+
       readsize = buflen;
       if (readsize > nmp->nm_rsize)
         {
@@ -733,14 +720,14 @@ static ssize_t nfs_read(FAR struct file *filep, char *buffer, size_t buflen)
       /* Make sure that the attempted read size does not exceed the IO buffer size */
 
       tmp = SIZEOF_rpc_reply_read(readsize);
-      if (tmp > np->n_buflen)
+      if (tmp > nmp->nm_buflen)
         {
-          readsize -= (tmp - np->n_buflen);
+          readsize -= (tmp - nmp->nm_buflen);
         }
 
       /* Initialize the request */
 
-      ptr     = (FAR uint32_t*)&request.read;
+      ptr     = (FAR uint32_t*)&nmp->nm_msgbuffer.read.read;
       reqlen  = 0;
 
       /* Copy the variable length, file handle */
@@ -764,12 +751,12 @@ static ssize_t nfs_read(FAR struct file *filep, char *buffer, size_t buflen)
       reqlen += sizeof(uint32_t);
 
       /* Perform the read */
- 
+
       fvdbg("Reading %d bytes\n", readsize);
       nfs_statistics(NFSPROC_READ);
       error = nfs_request(nmp, NFSPROC_READ,
-                          (FAR void *)&request, reqlen,
-                          (FAR void *)np->n_iobuffer, np->n_buflen);
+                          (FAR void *)&nmp->nm_msgbuffer.read, reqlen,
+                          (FAR void *)nmp->nm_iobuffer, nmp->nm_buflen);
       if (error)
         {
           fdbg("ERROR: nfs_request failed: %d\n", error);
@@ -780,7 +767,7 @@ static ssize_t nfs_read(FAR struct file *filep, char *buffer, size_t buflen)
        * response data.
        */
 
-      ptr = (FAR uint32_t *)&((FAR struct rpc_reply_read *)np->n_iobuffer)->read;
+      ptr = (FAR uint32_t *)&((FAR struct rpc_reply_read *)nmp->nm_iobuffer)->read;
 
       /* Check if attributes are included in the responses */
 
@@ -850,7 +837,6 @@ static ssize_t nfs_write(FAR struct file *filep, const char *buffer,
 {
   struct nfsmount       *nmp;
   struct nfsnode        *np;
-  struct rpc_reply_write resok;
   ssize_t                writesize;
   ssize_t                bufsize;
   ssize_t                byteswritten;
@@ -897,7 +883,7 @@ static ssize_t nfs_write(FAR struct file *filep, const char *buffer,
   for (byteswritten = 0; byteswritten < buflen; )
     {
       /* Make sure that the attempted write size does not exceed the RPC maximum */
- 
+
       writesize = buflen;
       if (writesize > nmp->nm_wsize)
         {
@@ -907,9 +893,9 @@ static ssize_t nfs_write(FAR struct file *filep, const char *buffer,
       /* Make sure that the attempted read size does not exceed the IO buffer size */
 
       bufsize = SIZEOF_rpc_call_write(writesize);
-      if (bufsize > np->n_buflen)
+      if (bufsize > nmp->nm_buflen)
         {
-          writesize -= (bufsize - np->n_buflen);
+          writesize -= (bufsize - nmp->nm_buflen);
         }
 
       /* Initialize the request.  Here we need an offset pointer to the write
@@ -917,7 +903,7 @@ static ssize_t nfs_write(FAR struct file *filep, const char *buffer,
        * RPC calls in that the entry RPC calls messasge lies in the I/O buffer
        */
 
-      ptr     = (FAR uint32_t *)&((FAR struct rpc_call_write *)np->n_iobuffer)->write;
+      ptr     = (FAR uint32_t *)&((FAR struct rpc_call_write *)nmp->nm_iobuffer)->write;
       reqlen  = 0;
 
       /* Copy the variable length, file handle */
@@ -952,8 +938,8 @@ static ssize_t nfs_write(FAR struct file *filep, const char *buffer,
 
       nfs_statistics(NFSPROC_WRITE);
       error = nfs_request(nmp, NFSPROC_WRITE,
-                          (FAR void *)np->n_iobuffer, reqlen,
-                          (FAR void *)&resok, sizeof(struct rpc_reply_write));
+                          (FAR void *)nmp->nm_iobuffer, reqlen,
+                          (FAR void *)&nmp->nm_msgbuffer.write, sizeof(struct rpc_reply_write));
       if (error)
         {
           fdbg("ERROR: nfs_request failed: %d\n", error);
@@ -962,7 +948,7 @@ static ssize_t nfs_write(FAR struct file *filep, const char *buffer,
 
       /* Get a pointer to the WRITE reply data */
 
-      ptr = (FAR uint32_t *)&resok.write;
+      ptr = (FAR uint32_t *)&nmp->nm_msgbuffer.write.write;
 
       /* Parse file_wcc.  First, check if WCC attributes follow. */
 
@@ -1129,8 +1115,6 @@ errout_with_semaphore:
 static int nfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir)
 {
   struct nfsmount *nmp;
-  uint32_t buffer[64];
-  struct rpc_call_readdir request;
   struct file_handle fhandle;
   struct nfs_fattr obj_attributes;
   uint32_t tmp;
@@ -1164,7 +1148,7 @@ static int nfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir)
    * the dirent structure.
    */
 
-  ptr     = (FAR uint32_t*)&request.readdir;
+  ptr     = (FAR uint32_t*)&nmp->nm_msgbuffer.readdir.readdir;
   reqlen  = 0;
 
   /* Copy the variable length, directory file handle */
@@ -1196,8 +1180,8 @@ static int nfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir)
 
   nfs_statistics(NFSPROC_READDIR);
   error = nfs_request(nmp, NFSPROC_READDIR,
-                      (FAR void *)&request, reqlen,
-                      (FAR void *)buffer, sizeof(buffer));
+                      (FAR void *)&nmp->nm_msgbuffer.readdir, reqlen,
+                      (FAR void *)nmp->nm_iobuffer, nmp->nm_buflen);
   if (error != OK)
     {
       fdbg("ERROR: nfs_request failed: %d\n", error);
@@ -1214,7 +1198,7 @@ static int nfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir)
    * 4) Values follows indication    - 4 bytes
    */
 
-  ptr = (uint32_t *)&((FAR struct rpc_reply_readdir *)buffer)->readdir;
+  ptr = (uint32_t *)&((FAR struct rpc_reply_readdir *)nmp->nm_iobuffer)->readdir;
 
   /* Check if attributes follow, if 0 so Skip over the attributes */
 
@@ -1363,48 +1347,35 @@ errout_with_semaphore:
  *
  ****************************************************************************/
 
-void nfs_decode_args(struct nfsmount *nmp, struct nfs_args *argp)
+void nfs_decode_args(struct nfs_mount_parameters *nprmt, struct nfs_args *argp)
 {
-  int adjsock = 0;
   int maxio;
 
-#ifdef CONFIG_NFS_TCPIP
-  /* Re-bind if rsrvd port requested and wasn't on one */
-
-  adjsock = !(nmp->nm_flag & NFSMNT_RESVPORT)
-    && (argp->flags & NFSMNT_RESVPORT);
-#endif
-
-  /* Also re-bind if we're switching to/from a connected UDP socket */
-
-  adjsock |= ((nmp->nm_flag & NFSMNT_NOCONN) != (argp->flags & NFSMNT_NOCONN));
-
   /* Update flags atomically.  Don't change the lock bits. */
 
-  nmp->nm_flag =
-    (argp->flags & ~NFSMNT_INTERNAL) | (nmp->nm_flag & NFSMNT_INTERNAL);
+  nprmt->flag = (argp->flags & ~NFSMNT_INTERNAL) | (nprmt->flag & NFSMNT_INTERNAL);
 
   if ((argp->flags & NFSMNT_TIMEO) && argp->timeo > 0)
     {
-      nmp->nm_timeo = (argp->timeo * NFS_HZ + 5) / 10;
-      if (nmp->nm_timeo < NFS_MINTIMEO)
+      nprmt->timeo = (argp->timeo * NFS_HZ + 5) / 10;
+      if (nprmt->timeo < NFS_MINTIMEO)
         {
-          nmp->nm_timeo = NFS_MINTIMEO;
+          nprmt->timeo = NFS_MINTIMEO;
         }
-      else if (nmp->nm_timeo > NFS_MAXTIMEO)
+      else if (nprmt->timeo > NFS_MAXTIMEO)
         {
-          nmp->nm_timeo = NFS_MAXTIMEO;
+          nprmt->timeo = NFS_MAXTIMEO;
         }
     }
 
   if ((argp->flags & NFSMNT_RETRANS) && argp->retrans > 1)
     {
-      nmp->nm_retry = (argp->retrans < NFS_MAXREXMIT)? argp->retrans : NFS_MAXREXMIT;
+      nprmt->retry = (argp->retrans < NFS_MAXREXMIT)? argp->retrans : NFS_MAXREXMIT;
     }
 
-  if (!(nmp->nm_flag & NFSMNT_SOFT))
+  if (!(nprmt->flag & NFSMNT_SOFT))
     {
-      nmp->nm_retry = NFS_MAXREXMIT + 1;  /* past clip limit */
+      nprmt->retry = NFS_MAXREXMIT + 1;  /* Past clip limit */
     }
 
   if (argp->flags & NFSMNT_NFSV3)
@@ -1425,88 +1396,70 @@ void nfs_decode_args(struct nfsmount *nmp, struct nfs_args *argp)
 
   if ((argp->flags & NFSMNT_WSIZE) && argp->wsize > 0)
     {
-      int osize = nmp->nm_wsize;
-      nmp->nm_wsize = argp->wsize;
+      nprmt->wsize = argp->wsize;
 
       /* Round down to multiple of blocksize */
 
-      nmp->nm_wsize &= ~(NFS_FABLKSIZE - 1);
-      if (nmp->nm_wsize <= 0)
+      nprmt->wsize &= ~(NFS_FABLKSIZE - 1);
+      if (nprmt->wsize <= 0)
         {
-          nmp->nm_wsize = NFS_FABLKSIZE;
+          nprmt->wsize = NFS_FABLKSIZE;
         }
-
-      adjsock |= (nmp->nm_wsize != osize);
     }
 
-  if (nmp->nm_wsize > maxio)
+  if (nprmt->wsize > maxio)
     {
-      nmp->nm_wsize = maxio;
+      nprmt->wsize = maxio;
     }
 
-  if (nmp->nm_wsize > MAXBSIZE)
+  if (nprmt->wsize > MAXBSIZE)
     {
-      nmp->nm_wsize = MAXBSIZE;
+      nprmt->wsize = MAXBSIZE;
     }
 
   if ((argp->flags & NFSMNT_RSIZE) && argp->rsize > 0)
     {
-      int osize = nmp->nm_rsize;
-      nmp->nm_rsize = argp->rsize;
+      nprmt->rsize = argp->rsize;
 
       /* Round down to multiple of blocksize */
 
-      nmp->nm_rsize &= ~(NFS_FABLKSIZE - 1);
-      if (nmp->nm_rsize <= 0)
+      nprmt->rsize &= ~(NFS_FABLKSIZE - 1);
+      if (nprmt->rsize <= 0)
         {
-          nmp->nm_rsize = NFS_FABLKSIZE;
+          nprmt->rsize = NFS_FABLKSIZE;
         }
-
-      adjsock |= (nmp->nm_rsize != osize);
     }
 
-  if (nmp->nm_rsize > maxio)
+  if (nprmt->rsize > maxio)
     {
-      nmp->nm_rsize = maxio;
+      nprmt->rsize = maxio;
     }
 
-  if (nmp->nm_rsize > MAXBSIZE)
+  if (nprmt->rsize > MAXBSIZE)
     {
-      nmp->nm_rsize = MAXBSIZE;
+      nprmt->rsize = MAXBSIZE;
     }
 
   if ((argp->flags & NFSMNT_READDIRSIZE) && argp->readdirsize > 0)
     {
-      nmp->nm_readdirsize = argp->readdirsize;
+      nprmt->readdirsize = argp->readdirsize;
 
       /* Round down to multiple of blocksize */
 
-      nmp->nm_readdirsize &= ~(NFS_DIRBLKSIZ - 1);
-      if (nmp->nm_readdirsize < NFS_DIRBLKSIZ)
+      nprmt->readdirsize &= ~(NFS_DIRBLKSIZ - 1);
+      if (nprmt->readdirsize < NFS_DIRBLKSIZ)
         {
-          nmp->nm_readdirsize = NFS_DIRBLKSIZ;
+          nprmt->readdirsize = NFS_DIRBLKSIZ;
         }
     }
   else if (argp->flags & NFSMNT_RSIZE)
     {
-      nmp->nm_readdirsize = nmp->nm_rsize;
+      nprmt->readdirsize = nprmt->rsize;
     }
 
-  if (nmp->nm_readdirsize > maxio)
+  if (nprmt->readdirsize > maxio)
     {
-      nmp->nm_readdirsize = maxio;
-    }
-
-  if (nmp->nm_so && adjsock)
-    {
-      nfs_disconnect(nmp);
-      if (nmp->nm_sotype == SOCK_DGRAM)
-        {
-          while (nfs_connect(nmp))
-            {
-              fvdbg("nfs_args: retrying connect\n");
-            }
-        }
+      nprmt->readdirsize = maxio;
     }
 }
 
@@ -1523,21 +1476,58 @@ void nfs_decode_args(struct nfsmount *nmp, struct nfs_args *argp)
 
 int mountnfs(struct nfs_args *argp, void **handle)
 {
-  FAR struct nfsmount *nmp;
-  struct nfsnode *np = NULL;
-  struct rpc_call_fs getattr;
-  struct rpc_reply_getattr resok;
-  int error = 0;
+  FAR struct nfsmount        *nmp;
+  struct rpc_call_fs          getattr;
+  struct rpc_reply_getattr    resok;
+  struct nfs_mount_parameters nprmt;
+  uint32_t                    buflen;
+  uint32_t                    tmp;
+  int                         error = 0;
+
+  /* Set initial values of the parameters for decode  */
+
+  nprmt.flag        = argp->flags;
+  nprmt.timeo       = NFS_TIMEO;
+  nprmt.retry       = NFS_RETRANS;
+  nprmt.wsize       = NFS_WSIZE;
+  nprmt.rsize       = NFS_RSIZE;
+  nprmt.readdirsize = NFS_READDIRSIZE;
+
+  nfs_decode_args(&nprmt, argp);
+
+   /* Determine the size of a buffer that will hold one RPC data transfer.
+    * First, get the maximum size of a read and a write transfer */
+
+  buflen = SIZEOF_rpc_call_write(nprmt.wsize);
+  tmp    = SIZEOF_rpc_reply_read(nprmt.rsize);
+
+  /* The buffer size will be the maximum of those two sizes */
+
+  if (tmp > buflen)
+    {
+      buflen = tmp;
+    }
+
+  /* But don't let the buffer size exceed the MSS of the socket type */
+
+  if (buflen > UIP_UDP_MSS)
+    {
+      buflen = UIP_UDP_MSS;
+    }
 
   /* Create an instance of the mountpt state structure */
 
-  nmp = (FAR struct nfsmount *)kzalloc(sizeof(struct nfsmount));
+  nmp = (FAR struct nfsmount *)kzalloc(SIZEOF_nfsmount(buflen));
   if (!nmp)
     {
       fdbg("ERROR: Failed to allocate mountpoint structure\n");
       return ENOMEM;
     }
 
+  /* Save the allocated I/O buffer size */
+
+  nmp->nm_buflen = (uint16_t)buflen;
+
   /* Initialize the allocated mountpt state structure. */
 
   /* Initialize the semaphore that controls access.  The initial count
@@ -1553,27 +1543,20 @@ int mountnfs(struct nfs_args *argp, void **handle)
 
   /* Set initial values of other fields */
 
-  nmp->nm_flag        = argp->flags;
-  nmp->nm_timeo       = NFS_TIMEO;
-  nmp->nm_retry       = NFS_RETRANS;
-  nmp->nm_wsize       = NFS_WSIZE;
-  nmp->nm_rsize       = NFS_RSIZE;
-  nmp->nm_readdirsize = NFS_READDIRSIZE;
+  nmp->nm_flag        = nprmt.flag;
+  nmp->nm_timeo       = nprmt.timeo;
+  nmp->nm_retry       = nprmt.retry;
+  nmp->nm_wsize       = nprmt.wsize;
+  nmp->nm_rsize       = nprmt.rsize;
+  nmp->nm_readdirsize = nprmt.readdirsize;
   nmp->nm_fhsize      = NFSX_V3FHMAX;
 
   strncpy(nmp->nm_path, argp->path, 90);
   memcpy(&nmp->nm_nam, &argp->addr, argp->addrlen);
 
-  nfs_decode_args(nmp, argp);
-
   /* Set up the sockets and per-host congestion */
 
   nmp->nm_sotype  = argp->sotype;
-  nmp->nm_soproto = argp->proto;
-
-  /* For Connection based sockets (TCP,...) defer the connect until
-   * the first request, in case the server is not responding.
-   */
 
   if (nmp->nm_sotype == SOCK_DGRAM)
     {
@@ -1587,33 +1570,12 @@ int mountnfs(struct nfs_args *argp, void **handle)
         }
     }
 
-  /* Create an instance of the file private data to describe the opened
-   * file.
-   */
-
-  np = (struct nfsnode *)kzalloc(sizeof(struct nfsnode));
-  if (!np)
-    {
-      fdbg("ERROR: Failed to allocate private data\n");
-      error = ENOMEM;
-      goto bad;
-     }
-
-  np->n_type             = NFDIR;
-  np->n_flags           |= (NFSNODE_OPEN | NFSNODE_MODIFIED);
-  nmp->nm_head           = np;
   nmp->nm_mounted        = true;
-  memcpy(&nmp->nm_fh, &nmp->nm_rpcclnt->rc_fh, sizeof(nfsfh_t));
-  nmp->nm_fhsize         = NFSX_V3FHMAX;
-  memcpy(&nmp->nm_head->n_fhandle, &nmp->nm_fh, sizeof(nfsfh_t));
-  nmp->nm_head->n_fhsize = nmp->nm_fhsize;
   nmp->nm_so             = nmp->nm_rpcclnt->rc_so;
+  memcpy(&nmp->nm_fh, &nmp->nm_rpcclnt->rc_fh, sizeof(nfsfh_t));
 
   /* Get the file attributes */
 
-  memset(&getattr, 0, sizeof(struct rpc_call_fs));
-  memset(&resok, 0, sizeof(struct rpc_reply_getattr));
-
   getattr.fs.fsroot.length = txdr_unsigned(nmp->nm_fhsize);
   memcpy(&getattr.fs.fsroot.handle, &nmp->nm_fh, sizeof(nfsfh_t));
 
@@ -1629,7 +1591,6 @@ int mountnfs(struct nfs_args *argp, void **handle)
   /* Save the file attributes */
 
   memcpy(&nmp->nm_fattr, &resok.attr, sizeof(struct nfs_fattr));
-  nfs_attrupdate(np, &resok.attr);
 
   /* Mounted! */
 
@@ -1637,16 +1598,9 @@ int mountnfs(struct nfs_args *argp, void **handle)
   nfs_semgive(nmp);
 
   fvdbg("Successfully mounted\n");
-  return 0;
+  return OK;
 
 bad:
-  /* Free all memory that was successfully allocated */
-
-  if (np)
-    {
-      kfree(np);
-    }
-
   if (nmp)
     {
       /* Disconnect from the server */
@@ -1718,21 +1672,32 @@ static int nfs_bind(struct inode *blkdriver, const void *data, void **handle)
  *
  ****************************************************************************/
 
-int nfs_unbind(void *handle, struct inode **blkdriver)
+int nfs_unbind(FAR void *handle, FAR struct inode **blkdriver)
 {
-  struct nfsmount *nmp = (struct nfsmount *)handle;
+  FAR struct nfsmount *nmp = (FAR struct nfsmount *)handle;
   int error;
 
   fvdbg("Entry\n");
+  DEBUGASSERT(nmp);
 
-  if (!nmp)
-    {
-      return -EINVAL;
-    }
+  /* Get exclusive access to the mount structure */
 
   nfs_semtake(nmp);
 
-  /* Umount */
+  /* Are there any open files?  We can tell if there are open files by looking
+   * at the list of file structures in the mount structure.  If this list
+   * not empty, then there are open files and we cannot unmount now (or a
+   * crash is sure to follow).
+   */
+
+  if (nmp->nm_head != NULL)
+    {
+      fdbg("ERROR;  There are open files\n");
+      error = EBUSY;
+      goto errout_with_semaphore;
+    }
+
+  /* No open file... Umount the file system. */
 
   error = rpcclnt_umount(nmp->nm_rpcclnt);
   if (error)
@@ -1740,19 +1705,112 @@ int nfs_unbind(void *handle, struct inode **blkdriver)
       fdbg("ERROR: rpcclnt_umount failed: %d\n", error);
     }
 
-  /* Disconnect */
+  /* Disconnect from the server */
 
   nfs_disconnect(nmp);
 
-  /* And free resources */
+  /* And free any allocated resources */
 
   sem_destroy(&nmp->nm_sem);
-  kfree(nmp->nm_head);
   kfree(nmp->nm_so);
   kfree(nmp->nm_rpcclnt);
   kfree(nmp);
 
   return -error;
+
+errout_with_semaphore:
+  nfs_semgive(nmp);
+  return -error;
+}
+
+/****************************************************************************
+ * Name: nfs_fsinfo
+ *
+ * Description:
+ *   Return information about root directory.
+ *
+ * Returned Value:
+ *   0 on success; positive errno value on failure
+ *
+ * Assumptions:
+ *   The caller has exclusive access to the NFS mount structure
+ *
+ ****************************************************************************/
+
+int nfs_fsinfo(FAR struct nfsmount *nmp)
+{
+  struct rpc_call_fs fsinfo;
+  struct rpc_reply_fsinfo fsp;
+  uint32_t pref;
+  uint32_t max;
+  int error = 0;
+
+  fsinfo.fs.fsroot.length = txdr_unsigned(nmp->nm_fhsize);
+  fsinfo.fs.fsroot.handle = nmp->nm_fh;
+
+  /* Request FSINFO from the server */
+
+  nfs_statistics(NFSPROC_FSINFO);
+  error = nfs_request(nmp, NFSPROC_FSINFO,
+                      (FAR void *)&fsinfo, sizeof(struct FS3args),
+                      (FAR void *)&fsp, sizeof(struct rpc_reply_fsinfo));
+  if (error)
+    {
+      return error;
+    }
+
+  /* Save the root file system attributes */
+
+//memcpy(&nmp->nm_fattr. &fsp.obj_attributes, sizeof(struct nfs_fattr));
+
+  pref = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_wtpref);
+  if (pref < nmp->nm_wsize)
+    {
+      nmp->nm_wsize = (pref + NFS_FABLKSIZE - 1) & ~(NFS_FABLKSIZE - 1);
+    }
+
+  max = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_wtmax);
+  if (max < nmp->nm_wsize)
+    {
+      nmp->nm_wsize = max & ~(NFS_FABLKSIZE - 1);
+      if (nmp->nm_wsize == 0)
+        {
+          nmp->nm_wsize = max;
+        }
+    }
+
+  pref = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_rtpref);
+  if (pref < nmp->nm_rsize)
+    {
+      nmp->nm_rsize = (pref + NFS_FABLKSIZE - 1) & ~(NFS_FABLKSIZE - 1);
+    }
+
+  max = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_rtmax);
+  if (max < nmp->nm_rsize)
+    {
+      nmp->nm_rsize = max & ~(NFS_FABLKSIZE - 1);
+      if (nmp->nm_rsize == 0)
+        {
+          nmp->nm_rsize = max;
+        }
+    }
+
+  pref = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_dtpref);
+  if (pref < nmp->nm_readdirsize)
+    {
+      nmp->nm_readdirsize = (pref + NFS_DIRBLKSIZ - 1) & ~(NFS_DIRBLKSIZ - 1);
+    }
+
+  if (max < nmp->nm_readdirsize)
+    {
+      nmp->nm_readdirsize = max & ~(NFS_DIRBLKSIZ - 1);
+      if (nmp->nm_readdirsize == 0)
+        {
+          nmp->nm_readdirsize = max;
+        }
+    }
+
+  return OK;
 }
 
 /****************************************************************************
@@ -1794,16 +1852,9 @@ static int nfs_statfs(struct inode *mountpt, struct statfs *sbp)
 
   /* Fill in the statfs info */
 
-  memset(sbp, 0, sizeof(struct statfs));
   sbp->f_type = NFS_SUPER_MAGIC;
 
-  if ((nmp->nm_flag & NFSMNT_GOTFSINFO) == 0)
-    {
-      (void)nfs_fsinfo(nmp);
-    }
-
-  memset(&fsstat, 0, sizeof(struct rpc_call_fs));
-  memset(&sfp, 0, sizeof(struct rpc_reply_fsstat));
+  (void)nfs_fsinfo(nmp);
 
   fsstat.fs.fsroot.length = txdr_unsigned(nmp->nm_fhsize);
   fsstat.fs.fsroot.handle = nmp->nm_fh;
@@ -1852,7 +1903,6 @@ static int nfs_remove(struct inode *mountpt, const char *relpath)
   struct file_handle      fhandle;
   struct nfs_fattr        fattr;
   char                    filename[NAME_MAX + 1];
-  struct rpc_call_remove  remove;
   struct rpc_reply_remove resok;
   FAR uint32_t           *ptr;
   int                     namelen;
@@ -1888,7 +1938,7 @@ static int nfs_remove(struct inode *mountpt, const char *relpath)
 
   /* Create the REMOVE RPC call arguments */
 
-  ptr    = (FAR uint32_t *)&remove.remove;
+  ptr    = (FAR uint32_t *)&nmp->nm_msgbuffer.removef.remove;
   reqlen = 0;
 
   /* Copy the variable length, directory file handle */
@@ -1914,23 +1964,9 @@ static int nfs_remove(struct inode *mountpt, const char *relpath)
 
   nfs_statistics(NFSPROC_REMOVE);
   error = nfs_request(nmp, NFSPROC_REMOVE,
-                      (FAR void *)&remove, reqlen,
+                      (FAR void *)&nmp->nm_msgbuffer.removef, reqlen,
                       (FAR void *)&resok, sizeof(struct rpc_reply_remove));
 
-  /* Check if the file removal was successful */
-
-#ifdef CONFIG_NFS_TCPIP
-  if (error == ENOENT)
-    {
-      /* If the first reply to the remove rpc is lost, the reply to the
-       * retransmitted request may be ENOENT if the file was in fact removed.
-       * Therefore, we cheat and return success.
-       */
-
-      error = OK;
-    }
-#endif
-
 errout_with_semaphore:
    nfs_semgive(nmp);
    return -error;
@@ -1953,7 +1989,6 @@ static int nfs_mkdir(struct inode *mountpt, const char *relpath, mode_t mode)
   struct file_handle     fhandle;
   struct nfs_fattr       fattr;
   char                   dirname[NAME_MAX + 1];
-  struct rpc_call_mkdir  request;
   struct rpc_reply_mkdir resok;
   FAR uint32_t          *ptr;
   uint32_t               tmp;
@@ -1990,7 +2025,7 @@ static int nfs_mkdir(struct inode *mountpt, const char *relpath, mode_t mode)
 
   /* Format the MKDIR call message arguments */
 
-  ptr    = (FAR uint32_t *)&request.mkdir;
+  ptr    = (FAR uint32_t *)&nmp->nm_msgbuffer.mkdir.mkdir;
   reqlen = 0;
 
   /* Copy the variable length, directory file handle */
@@ -2031,13 +2066,13 @@ static int nfs_mkdir(struct inode *mountpt, const char *relpath, mode_t mode)
   *ptr++  = nfs_true;             /* True: Uid value follows */
   *ptr++  = 0;                    /* UID = 0 (nobody) */
   reqlen += 2*sizeof(uint32_t);
-  
+
   /* Set the group ID to one */
 
   *ptr++  = nfs_true;            /* True: Gid value follows */
   *ptr++  = HTONL(1);            /* GID = 1 (nogroup) */
   reqlen += 2*sizeof(uint32_t);
-  
+
   /* No size */
 
   *ptr++  = nfs_false; /* False: No size value follows */
@@ -2053,7 +2088,7 @@ static int nfs_mkdir(struct inode *mountpt, const char *relpath, mode_t mode)
 
   nfs_statistics(NFSPROC_MKDIR);
   error = nfs_request(nmp, NFSPROC_MKDIR,
-                      (FAR void *)&request, reqlen,
+                      (FAR void *)&nmp->nm_msgbuffer.mkdir, reqlen,
                       (FAR void *)&resok, sizeof(struct rpc_reply_mkdir));
   if (error)
     {
@@ -2082,7 +2117,6 @@ static int nfs_rmdir(struct inode *mountpt, const char *relpath)
   struct file_handle     fhandle;
   struct nfs_fattr       fattr;
   char                   dirname[NAME_MAX + 1];
-  struct rpc_call_rmdir  request;
   struct rpc_reply_rmdir resok;
   FAR uint32_t          *ptr;
   int                    namelen;
@@ -2118,7 +2152,7 @@ static int nfs_rmdir(struct inode *mountpt, const char *relpath)
 
   /* Set up the RMDIR call message arguments */
 
-  ptr    = (FAR uint32_t *)&request.rmdir;
+  ptr    = (FAR uint32_t *)&nmp->nm_msgbuffer.rmdir.rmdir;
   reqlen = 0;
 
   /* Copy the variable length, directory file handle */
@@ -2144,22 +2178,9 @@ static int nfs_rmdir(struct inode *mountpt, const char *relpath)
 
   nfs_statistics(NFSPROC_RMDIR);
   error = nfs_request(nmp, NFSPROC_RMDIR,
-                          (FAR void *)&request, reqlen,
+                          (FAR void *)&nmp->nm_msgbuffer.rmdir, reqlen,
                           (FAR void *)&resok, sizeof(struct rpc_reply_rmdir));
 
-  /* Check if the removal was successful */
-
-#ifdef CONFIG_NFS_TCPIP
-  if (error == ENOENT)
-    {
-      /* If the first reply to the remove rpc is lost, the reply to the
-       * retransmitted request may be ENOENT if the file was in fact removed.
-       * Therefore, we cheat and return success.
-       */
-          error = 0;
-    }
-#endif
-
 errout_with_semaphore:
   nfs_semgive(nmp);
   return -error;
@@ -2185,7 +2206,6 @@ static int nfs_rename(struct inode *mountpt, const char *oldrelpath,
   char                    from_name[NAME_MAX+1];
   char                    to_name[NAME_MAX+1];
   struct nfs_fattr        fattr;
-  struct rpc_call_rename  request;
   struct rpc_reply_rename resok;
   FAR uint32_t           *ptr;
   int                     namelen;
@@ -2230,7 +2250,7 @@ static int nfs_rename(struct inode *mountpt, const char *oldrelpath,
 
   /* Format the RENAME RPC arguments */
 
-  ptr    = (FAR uint32_t *)&request.rename;
+  ptr    = (FAR uint32_t *)&nmp->nm_msgbuffer.renamef.rename;
   reqlen = 0;
 
   /* Copy the variable length, 'from' directory file handle */
@@ -2276,23 +2296,9 @@ static int nfs_rename(struct inode *mountpt, const char *oldrelpath,
 
   nfs_statistics(NFSPROC_RENAME);
   error = nfs_request(nmp, NFSPROC_RENAME,
-                      (FAR void *)&request, reqlen,
+                      (FAR void *)&nmp->nm_msgbuffer.renamef, reqlen,
                       (FAR void *)&resok, sizeof(struct rpc_reply_rename));
 
-  /* Check if the rename was successful */
-
-#ifdef CONFIG_NFS_TCPIP
-  if (error == ENOENT)
-    {
-      /* If the first reply to the remove rpc is lost, the reply to the
-       * retransmitted request may be ENOENT if the file was in fact removed.
-       * Therefore, we cheat and return success.
-       */
-
-      error = 0;
-    }
-#endif
-
 errout_with_semaphore:
   nfs_semgive(nmp);
   return -error;
@@ -2352,7 +2358,7 @@ static int nfs_stat(struct inode *mountpt, const char *relpath,
    */
 
   tmp = fxdr_unsigned(uint32_t, obj_attributes.fa_mode);
-      
+
   /* Here we exploit the fact that most mode bits are the same in NuttX
    * as in the NFSv3 spec.
    */
@@ -2423,58 +2429,3 @@ errout_with_semaphore:
   nfs_semgive(nmp);
   return -error;
 }
-
-#ifdef COMP
-/****************************************************************************
- * Name: nfs_sync
- *
- * Description: Flush out the buffer cache
- *
- * Returned Value:
- *   0 on success; a negated errno value on failure.
- *
- ****************************************************************************/
-
-int nfs_sync(struct file *filep)
-{
-  struct inode *inode;
-  struct nfsmount *nmp;
-  struct nfsnode *np;
-  int error = 0;
-
-  /* Sanity checks */
-
-  DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL);
-
-  /* Recover our private data from the struct file instance */
-
-  np    = filep->f_priv;
-  inode = filep->f_inode;
-  nmp   = inode->i_private;
-
-  DEBUGASSERT(nmp != NULL);
-
-  /* Make sure that the mount is still healthy */
-
-  nfs_semtake(nmp);
-  error = nfs_checkmount(nmp);
-  if (error != OK)
-    {
-      fdbg("ERROR: nfs_checkmount failed: %d\n", error);
-      goto errout_with_semaphore;
-    }
-
-  /* Force stale buffer cache information to be flushed. */
-
-  /* Check if the has been modified in any way */
-
-  if ((np->n_flags & NFSNODE_MODIFIED) != 0)
-    {
-      //error = VOP_FSYNC(vp, cred, waitfor, p);
-    }
-
-errout_with_semaphore:
-  nfs_semgive(nmp);
-  return -error;
-}
-#endif
diff --git a/fs/nfs/rpc.h b/fs/nfs/rpc.h
index 82d5e46ee1..5177108b7d 100644
--- a/fs/nfs/rpc.h
+++ b/fs/nfs/rpc.h
@@ -277,9 +277,6 @@ struct rpc_call_header
   uint32_t rp_vers;           /* version */
   uint32_t rp_proc;           /* procedure */
   struct rpc_auth_info rpc_auth;
-#ifdef CONFIG_NFS_UNIX_AUTH
-  struct auth_unix rpc_unix;
-#endif
   struct rpc_auth_info rpc_verf;
 };
 
@@ -485,21 +482,10 @@ struct  rpcclnt
 
   uint8_t rc_clntflags;       /* For RPCCLNT_* flags  */
   uint8_t rc_sotype;          /* Type of socket */
-  uint8_t rc_soproto;         /* and protocol */
 
   /* These describe the current RPC call */
 
   uint8_t rc_callflags;       /* For RPCCALL_* flags */
-
-  /* Authentication: Can be RPCAUTH_NULL, RPCAUTH_KERBV4, RPCAUTH_UNIX
-   * Should be kept in XDR form 
-   */
-
-  /* RPCAUTH_UNIX */
-#ifdef CONFIG_NFS_UNIX_AUTH
-  struct rpc_auth_info rc_oldauth; /* authentication */
-  void                *rc_auth;
-#endif
 };
 
 /****************************************************************************
diff --git a/fs/nfs/rpc_clnt.c b/fs/nfs/rpc_clnt.c
index a749d7411b..0dcb7f2b73 100644
--- a/fs/nfs/rpc_clnt.c
+++ b/fs/nfs/rpc_clnt.c
@@ -98,23 +98,6 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
-/* There is a congestion window for outstanding RPCs maintained per mount
- * point. The cwnd size is adjusted in roughly the way that: Van Jacobson,
- * Congestion avoidance and Control, In "Proceedings of SIGCOMM '88". ACM,
- * August 1988. describes for TCP. The cwnd size is chopped in half on a
- * retransmit timeout and incremented by 1/cwnd when each RPC reply is
- * received and a full cwnd of RPCs is in progress. (The sent count and cwnd
- * are scaled for integer arith.) Variants of "slow start" were tried and
- * were found to be too much of a performance hit (ave. rtt 3 times larger),
- * I suspect due to the large rtt that nfs RPCs have.
- */
-
-#define RPC_CWNDSCALE   256
-#define RPC_MAXCWND     (RPC_CWNDSCALE * 32)
-
-#define RPC_ERRSTR_ACCEPTED_SIZE 6
-#define RPC_ERRSTR_AUTH_SIZE 6
-
 /* Increment RPC statistics */
 
 #ifdef CONFIG_NFS_STATISTICS
@@ -159,9 +142,6 @@ static int rpcclnt_receive(FAR struct rpcclnt *rpc, struct sockaddr *aname,
                            int proc, int program, void *reply, size_t resplen);
 static int rpcclnt_reply(FAR struct rpcclnt *rpc, int procid, int prog,
                          void *reply, size_t resplen);
-#ifdef CONFIG_NFS_TCPIP
-static int rpcclnt_reconnect(FAR struct rpcclnt *rpc);
-#endif
 static uint32_t rpcclnt_newxid(void);
 static void rpcclnt_fmtheader(FAR struct rpc_call_header *ch,
                               uint32_t xid, int procid, int prog, int vers);
@@ -221,208 +201,19 @@ static int rpcclnt_receive(FAR struct rpcclnt *rpc, struct sockaddr *aname,
                            int proc, int program, void *reply, size_t resplen)
 {
   ssize_t nbytes;
-#ifdef CONFIG_NFS_TCPIP
-  uint32_t resplen;
-  int sotype;
-#endif
   int error = 0;
-  int errval;
 
-#ifdef CONFIG_NFS_TCPIP
-  /* Set up arguments for psock_recvfrom() */
-
-  sotype = rpc->rc_sotype;
-
-  if (sotype != SOCK_DGRAM)
+  if (rpc->rc_so == NULL)
     {
-    tryagain:
-
-      /* Check for fatal errors and resending request. */
-
-      if (rpc->rc_so == NULL)
-        {
-          error = rpcclnt_reconnect(rpc);
-          if (error)
-            {
-              return error;
-            }
-
-          goto tryagain;
-        }
-
-      while (rpc->rc_callflags & RPCCALL_MUSTRESEND)
-        {
-          rpc_statistics(rpcretries);
-          error = rpcclnt_send(rpc, proc, program, call, reqlen);
-          if (error)
-            {
-              if (error == EINTR || error == ERESTART)
-                {
-                  return error;
-                }
-
-              error = rpcclnt_reconnect(rpc);
-              if (error != OK)
-                {
-                  return error;
-                }
-
-              goto tryagain;
-            }
-        }
-
-      if (sotype == SOCK_STREAM)
-        {
-          errval = 0;
-          do
-            {
-              socklen_t fromlen = sizeof(*rpc->rc_name)
-              nbytes = psock_recvfrom(rpc->rc_so, reply, resplen,
-                                      MSG_WAITALL, rpc->rc_name,
-                                      &fromlen);
-              if (nbytes < 0)
-                {
-                  errval = errno;
-                  fdbg("ERROR: psock_recvfrom returned %d\n", errval);
-                }
-            }
-          while (errval == EWOULDBLOCK);
-
-          if (nbytes < 0)
-            {
-              error = errval;
-            }
-          else if (nbytes < resplen)
-            {
-              fdbg("ERROR: Short receive from RPC server\n");
-              fvdbg("       Expected %d bytes, received %d bytes\n",
-                    resplen, nbytes);
-              error = EPIPE;
-            }
-          else
-            {
-              error = 0;
-            }
-
-#warning "What is resplen?  This logic is not right!"
-          resplen = ntohl(resplen) & ~0x80000000;
-
-          /* This is SERIOUS! We are out of sync with the
-           * sender and forcing a disconnect/reconnect is all I
-           * can do.
-           */
-
-          else if (resplen > RPC_MAXPACKET)
-            {
-              fdbg("ERROR: Impossible length rom RPC server: %d\n", resplen);
-              error = EFBIG;
-              goto errout;
-            }
-
-          errval = 0
-          do
-            {
-              socklen_t fromlen = sizeof(*rpc->rc_name);
-              nbytes = psock_recvfrom(so, reply, sizeof(*reply),
-                                      MSG_WAITALL, rpc->rc_name,
-                                      &fromlen);
-              if (nbytes < 0)
-                {
-                  errval = errno;
-                  fdbg("ERROR: psock_recvfrom failed: %d\n", errval);
-                }
-            }
-          while (errval == EWOULDBLOCK || errval == EINTR || errval == ERESTART);
-
-          if (nbytes < 0)
-            {
-              error = errval;
-              goto errout;
-            }
-          else if (nbytes < resplen)
-            {
-              fdbg("ERROR: Short receive from RPC server\n");
-              fvdbg("       Expected %d bytes, received %d bytes\n",
-                    resplen, nbytes);
-              error = EPIPE;
-            }
-          else
-            {
-              error = 0;
-            }
-        }
-      else
-        {
-          /* NB: Since uio_resid is big, MSG_WAITALL is ignored
-           * and psock_recvfrom() will return when it has either a
-           * control msg or a data msg. We have no use for
-           * control msg., but must grab them and then throw
-           * them away so we know what is going on.
-           */
-
-          errval = 0;
-          do
-            {
-              socklen_t fromlen = sizeof(*rpc->rc_name);
-              nbytes = psock_recvfrom(so, reply, sizeof(*reply), 0,
-                                      rpc->rc_name, &fromlen);
-              if (nbytes < 0)
-                {
-                  errval = errno;
-                  fdbg("ERROR: psock_recvfrom failed: %d\n", errval);
-                }
-            }
-          while (errval == EWOULDBLOCK || nbytes == 0);
-
-          if (nbytes < 0)
-            {
-              error = errval;
-              goto errout;
-            }
-          else if (nbytes < resplen)
-            {
-              fdbg("ERROR: Short receive from RPC server\n");
-              fvdbg("       Expected %d bytes, received %d bytes\n",
-                    resplen, nbytes);
-              error = EPIPE;
-            }
-          else
-            {
-              error = 0;
-            }
-        }
-
-    errout:
-      if (error != 0 && error != EINTR && error != ERESTART)
-        {
-          if (error != EPIPE)
-            {
-              fdbg("ERROR: Receive error %d from RPC server\n", error);
-            }
-
-          error = rpcclnt_reconnect(rpc);
-          if (error == 0)
-            {
-              goto tryagain;
-            }
-        }
+      return EACCES;
     }
-  else
-#endif
-    {
-      if (rpc->rc_so == NULL)
-        {
-          return EACCES;
-        }
 
-      socklen_t fromlen = sizeof(struct sockaddr);
-      nbytes = psock_recvfrom(rpc->rc_so, reply, resplen, 0, aname, &fromlen);
-      if (nbytes < 0)
-        {
-          errval = errno;
-          fdbg("ERROR: psock_recvfrom failed: %d\n", errval);
-          error = errval;
-        }
+  socklen_t fromlen = sizeof(struct sockaddr);
+  nbytes = psock_recvfrom(rpc->rc_so, reply, resplen, 0, aname, &fromlen);
+  if (nbytes < 0)
+    {
+      error = errno;
+      fdbg("ERROR: psock_recvfrom failed: %d\n", error);
     }
 
   return error;
@@ -467,7 +258,7 @@ static int rpcclnt_reply(FAR struct rpcclnt *rpc, int procid, int prog,
 
       replyheader = (FAR struct rpc_reply_header *)reply;
       rxid       = replyheader->rp_xid;
- 
+
       if (replyheader->rp_direction != rpc_reply)
         {
           rpc_statistics(rpcinvalid);
@@ -522,7 +313,7 @@ static void rpcclnt_fmtheader(FAR struct rpc_call_header *ch,
                               uint32_t xid, int prog, int vers, int procid)
 {
   /* Format the call header */
- 
+
   ch->rp_xid            = txdr_unsigned(xid);
   ch->rp_direction      = rpc_call;
   ch->rp_rpcvers        = rpc_vers;
@@ -535,14 +326,6 @@ static void rpcclnt_fmtheader(FAR struct rpc_call_header *ch,
   ch->rpc_auth.authtype = rpc_auth_null;
   ch->rpc_auth.authlen  = 0;
 
-#ifdef CONFIG_NFS_UNIX_AUTH
-  ch->rpc_unix.stamp    = txdr_unsigned(1);
-  ch->rpc_unix.hostname = 0;
-  ch->rpc_unix.uid      = setuid;
-  ch->rpc_unix.gid      = setgid;
-  ch->rpc_unix.gidlist  = 0;
-#endif
-
   /* rpc_verf part (auth_null) */
 
   ch->rpc_verf.authtype  = rpc_auth_null;
@@ -594,7 +377,6 @@ int rpcclnt_connect(struct rpcclnt *rpc)
   /* Create the socket */
 
   saddr = rpc->rc_name;
-  memset(&sin, 0, sizeof(sin));
 
   /* Create an instance of the socket state structure */
 
@@ -605,7 +387,7 @@ int rpcclnt_connect(struct rpcclnt *rpc)
       return ENOMEM;
     }
 
-  error = psock_socket(saddr->sa_family, rpc->rc_sotype, rpc->rc_soproto, so);
+  error = psock_socket(saddr->sa_family, rpc->rc_sotype, IPPROTO_UDP, so);
   if (error < 0)
     {
       errval = errno;
@@ -678,8 +460,6 @@ int rpcclnt_connect(struct rpcclnt *rpc)
    * Get port number for MOUNTD.
    */
 
-  memset(&sdata, 0, sizeof(struct rpc_call_pmap));
-  memset(&rdata, 0, sizeof(struct rpc_reply_pmap));
   sdata.pmap.prog = txdr_unsigned(RPCPROG_MNT);
   sdata.pmap.vers = txdr_unsigned(RPCMNT_VER1);
   sdata.pmap.proc = txdr_unsigned(IPPROTO_UDP);
@@ -707,8 +487,6 @@ int rpcclnt_connect(struct rpcclnt *rpc)
 
   /* Do RPC to mountd. */
 
-  memset(&mountd, 0, sizeof(struct rpc_call_mount));
-  memset(&mdata, 0, sizeof(struct rpc_reply_mount));
   strncpy(mountd.mount.rpath, rpc->rc_path, 90);
   mountd.mount.len =  txdr_unsigned(sizeof(mountd.mount.rpath));
 
@@ -734,8 +512,6 @@ int rpcclnt_connect(struct rpcclnt *rpc)
    * NFS port in the socket.
    */
 
-  memset(&sdata, 0, sizeof(struct rpc_call_pmap));
-  memset(&rdata, 0, sizeof(struct rpc_reply_pmap));
   sa->sin_port = htons(PMAPPORT);
 
   error = psock_connect(rpc->rc_so, saddr, sizeof(*saddr));
@@ -776,35 +552,6 @@ bad:
   return error;
 }
 
-/* Reconnect routine: Called when a connection is broken on a reliable
- * protocol. - clean up the old socket - nfs_connect() again - set
- * RPCCALL_MUSTRESEND for all outstanding requests on mount point If this
- * fails the mount point is DEAD!
- */
-
-#ifdef CONFIG_NFS_TCPIP
-int rpcclnt_reconnect(FAR struct rpcclnt *rpc)
-{
-  int error;
-
-  rpcclnt_disconnect(rpc);
-  do
-    {
-      error = rpcclnt_connect(rpc);
-      if (error != OK)
-        {
-          fdbg("ERROR: rpcclnt_connect failed: %d\n", error);
-          if (error == EINTR || error == ERESTART)
-            {
-              return EINTR;
-            }
-        }
-    }
-  while (error != OK)
-  return OK;
-}
-#endif
-
 void rpcclnt_disconnect(struct rpcclnt *rpc)
 {
   struct socket *so;
@@ -833,8 +580,6 @@ int rpcclnt_umount(struct rpcclnt *rpc)
    * Get port number for MOUNTD.
    */
 
-  memset(&sdata, 0, sizeof(struct rpc_call_pmap));
-  memset(&rdata, 0, sizeof(struct rpc_reply_pmap));
   sa->sin_port = htons(PMAPPORT);
 
   error = psock_connect(rpc->rc_so, saddr, sizeof(*saddr));
@@ -869,9 +614,6 @@ int rpcclnt_umount(struct rpcclnt *rpc)
 
   /* Do RPC to umountd. */
 
-  memset(&mountd, 0, sizeof(struct rpc_call_mount));
-  memset(&mdata, 0, sizeof(struct rpc_reply_mount));
-
   strncpy(mountd.mount.rpath, rpc->rc_path, 92);
   mountd.mount.len =  txdr_unsigned(sizeof(mountd.mount.rpath));
 
diff --git a/include/nuttx/fs/nfs.h b/include/nuttx/fs/nfs.h
index fcf9c3f7ba..3ce62dfc1c 100644
--- a/include/nuttx/fs/nfs.h
+++ b/include/nuttx/fs/nfs.h
@@ -66,22 +66,13 @@ struct nfs_args
   uint8_t version;               /* Args structure version number */
   uint8_t addrlen;               /* Length of address */
   uint8_t sotype;                /* Socket type */
-  uint8_t proto;                 /* and Protocol */
   int     flags;                 /* Flags */
   int     wsize;                 /* Write size in bytes */
   int     rsize;                 /* Read size in bytes */
   int     readdirsize;           /* readdir size in bytes */
   int     timeo;                 /* Initial timeout in .1 secs */
   int     retrans;               /* Times to retry send */
-//int     maxgrouplist;          /* Max. size of group list */
-//int     readahead;             /* # of blocks to readahead */
-//int     leaseterm;             /* Term (sec) of lease */
-//int     deadthresh;            /* Retrans threshold */
   char   *path;                  /* Server's path of the directory being mount */
-  int     acregmin;              /* Cache attrs for reg files min time */
-  int     acregmax;              /* Cache attrs for reg files max time */
-  int     acdirmin;              /* Cache attrs for dirs min time */
-  int     acdirmax;              /* Cache attrs for dirs max time */
   struct  sockaddr_storage addr; /* File server address (requires 32-bit alignment) */
 };
 
diff --git a/tools/mkconfig.c b/tools/mkconfig.c
index 5bacb24a64..97e2a9c34c 100644
--- a/tools/mkconfig.c
+++ b/tools/mkconfig.c
@@ -206,15 +206,19 @@ int main(int argc, char **argv, char **envp)
   printf("#ifdef CONFIG_DISABLE_MOUNTPOINT\n");
   printf("# undef CONFIG_FS_FAT\n");
   printf("# undef CONFIG_FS_ROMFS\n");
+  printf("# undef CONFIG_FS_NXFFS\n");
+  printf("# undef CONFIG_APPS_BINDIR\n");
+  printf("# undef CONFIG_NFS\n");
   printf("#endif\n\n");
   printf("/* Check if any readable and writable filesystem (OR USB storage) is supported */\n\n");
   printf("#undef CONFIG_FS_READABLE\n");
   printf("#undef CONFIG_FS_WRITABLE\n");
   printf("#if defined(CONFIG_FS_FAT) || defined(CONFIG_FS_ROMFS) || defined(CONFIG_USBMSC) || \\\n");
-  printf("    defined(CONFIG_FS_NXFFS) || defined(CONFIG_APPS_BINDIR)\n");
+  printf("    defined(CONFIG_FS_NXFFS) || defined(CONFIG_APPS_BINDIR) || defined(CONFIG_NFS)\n");
   printf("# define CONFIG_FS_READABLE 1\n");
   printf("#endif\n\n");
-  printf("#if defined(CONFIG_FS_FAT) || defined(CONFIG_USBMSC) || defined(CONFIG_FS_NXFFS)\n");
+  printf("#if defined(CONFIG_FS_FAT) || defined(CONFIG_USBMSC) || defined(CONFIG_FS_NXFFS) || \\\n");
+  printf("    defined(CONFIG_NFS)\n");
   printf("# define CONFIG_FS_WRITABLE 1\n");
   printf("#endif\n\n");
   printf("/* There can be no network support with no socket descriptors */\n\n");
@@ -234,6 +238,10 @@ int main(int argc, char **argv, char **envp)
   printf("# undef CONFIG_NET_UDP\n");
   printf("# undef CONFIG_NET_ICMP\n");
   printf("#endif\n\n");
+  printf("/* NFS client can only be provided on top of UDP network support */\n\n");
+  printf("#if !defined(CONFIG_NET) || !defined(CONFIG_NET_UDP)\n");
+  printf("# undef CONFIG_NFS\n");
+  printf("#endif\n\n");
   printf("/* Verbose debug and sub-system debug only make sense if debug is enabled */\n\n");
   printf("#ifndef CONFIG_DEBUG\n");
   printf("# undef CONFIG_DEBUG_VERBOSE\n");