[svn-r12739] Added Direct I/O driver to VFD. It's only supported by SGI Altix (cobalt). There's a configure

option --enable-direct-vfd/--disable-direct-vfd to enable/disable Direct I/O support.  The default
is enabled.  There's a small test in test/vfd.c.  Another way to test it is to set environment
variable HDF5_DRIVER to "direct" and run "make check" in the test/ directory.  There'll be some
further improvement in the following checkin including allowing user to provide memory boundary
value, file block size, and copying buffer size.

11 files changed, 1056 insertions, 10 deletions

diff --git a/src/H5F.c b/src/H5F.c
index a12c97d..35787f7 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -41,6 +41,7 @@
 #include "H5FDsec2.h"		/*Posix unbuffered I/O			*/
 #include "H5FDstdio.h"		/* Standard C buffered I/O		*/
 #include "H5FDstream.h"         /*in-memory files streamed via sockets  */
+#include "H5FDdirect.h"         /*Linux direct I/O			*/
 
 /* Struct only used by functions H5F_get_objects and H5F_get_objects_cb */
 typedef struct H5F_olist_t {
diff --git a/src/H5FD.c b/src/H5FD.c
index f5c7a85..952bad9 100644
--- a/src/H5FD.c
+++ b/src/H5FD.c
@@ -43,6 +43,7 @@
 #include "H5FDsec2.h"		/* POSIX unbuffered file I/O		*/
 #include "H5FDstdio.h"		/* Standard C buffered I/O		*/
 #include "H5FDstream.h"     	/* In-memory files streamed via sockets */
+#include "H5FDdirect.h"		/* Direct file I/O			*/
 #include "H5FLprivate.h"	/* Free lists                           */
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5MMprivate.h"	/* Memory management			*/
@@ -161,6 +162,9 @@ H5FD_term_interface(void)
             /* Reset the VFL drivers, if they've been closed */
             if(H5I_nmembers(H5I_VFL)==0) {
                 H5FD_sec2_term();
+#ifdef H5_HAVE_DIRECT 
+                H5FD_direct_term();
+#endif           
                 H5FD_log_term();
                 H5FD_stdio_term();
                 H5FD_family_term();
diff --git a/src/H5FDdirect.c b/src/H5FDdirect.c
new file mode 100644
index 0000000..54283b5
--- /dev/null
+++ b/src/H5FDdirect.c
@@ -0,0 +1,989 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Programmer:  Raymond Lu <slu@hdfgroup.uiuc.edu>
+ *              Wednesday, 20 September 2006
+ *
+ * Purpose:	The Direct I/O file driver forces the data to be written to
+ *		the file directly without being copied into system kernel 
+ *		buffer.  The main system support this feature is Linux.
+ */
+
+/* Interface initialization */
+#define H5_INTERFACE_INIT_FUNC	H5FD_direct_init_interface
+
+/* For system function posix_memalign */
+#define _XOPEN_SOURCE 600
+
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5Fprivate.h"		/* File access				*/
+#include "H5FDprivate.h"	/* File drivers				*/
+#include "H5FDdirect.h"		/* Direct file driver			*/
+#include "H5FLprivate.h"	/* Free Lists                           */
+#include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5MMprivate.h"	/* Memory management			*/
+#include "H5Pprivate.h"		/* Property lists			*/
+
+#ifdef H5_HAVE_DIRECT
+
+/* The driver identification number, initialized at runtime */
+static hid_t H5FD_DIRECT_g = 0;
+
+/* File operations */
+#define OP_UNKNOWN	0
+#define OP_READ		1
+#define OP_WRITE	2
+
+/*
+ * The description of a file belonging to this driver. The `eoa' and `eof'
+ * determine the amount of hdf5 address space in use and the high-water mark
+ * of the file (the current size of the underlying Unix file). The `pos'
+ * value is used to eliminate file position updates when they would be a
+ * no-op. Unfortunately we've found systems that use separate file position
+ * indicators for reading and writing so the lseek can only be eliminated if
+ * the current operation is the same as the previous operation.  When opening
+ * a file the `eof' will be set to the current file size, `eoa' will be set
+ * to zero, `pos' will be set to H5F_ADDR_UNDEF (as it is when an error
+ * occurs), and `op' will be set to H5F_OP_UNKNOWN.
+ */
+typedef struct H5FD_direct_t {
+    H5FD_t	pub;			/*public stuff, must be first	*/
+    int		fd;			/*the unix file			*/
+    haddr_t	eoa;			/*end of allocated region	*/
+    haddr_t	eof;			/*end of file; current file size*/
+    haddr_t	pos;			/*current file I/O position	*/
+    int		op;			/*last operation		*/
+#ifndef WIN32
+    /*
+     * On most systems the combination of device and i-node number uniquely
+     * identify a file.
+     */
+    dev_t	device;			/*file device number		*/
+#ifdef H5_VMS
+    ino_t	inode[3];		/*file i-node number		*/
+#else
+    ino_t	inode;			/*file i-node number		*/
+#endif /*H5_VMS*/
+#else
+    /*
+     * On WIN32 the low-order word of a unique identifier associated with the
+     * file and the volume serial number uniquely identify a file. This number
+     * (which, both? -rpm) may change when the system is restarted or when the
+     * file is opened. After a process opens a file, the identifier is
+     * constant until the file is closed. An application can use this
+     * identifier and the volume serial number to determine whether two
+     * handles refer to the same file.
+     */
+    DWORD fileindexlo;
+    DWORD fileindexhi;
+#endif
+} H5FD_direct_t;
+
+/*
+ * This driver supports systems that have the lseek64() function by defining
+ * some macros here so we don't have to have conditional compilations later
+ * throughout the code.
+ *
+ * file_offset_t:	The datatype for file offsets, the second argument of
+ *			the lseek() or lseek64() call.
+ *
+ * file_seek:		The function which adjusts the current file position,
+ *			either lseek() or lseek64().
+ */
+/* adding for windows NT file system support. */
+
+#ifdef H5_HAVE_LSEEK64
+#   define file_offset_t	off64_t
+#   define file_seek		lseek64
+#   define file_truncate	ftruncate64
+#elif defined (WIN32) && !defined(__MWERKS__)
+# /*MSVC*/
+#   define file_offset_t __int64
+#   define file_seek _lseeki64
+#   define file_truncate	_chsize
+#else
+#   define file_offset_t	off_t
+#   define file_seek		lseek
+#   define file_truncate	HDftruncate
+#endif
+
+/*
+ * These macros check for overflow of various quantities.  These macros
+ * assume that file_offset_t is signed and haddr_t and size_t are unsigned.
+ *
+ * ADDR_OVERFLOW:	Checks whether a file address of type `haddr_t'
+ *			is too large to be represented by the second argument
+ *			of the file seek function.
+ *
+ * SIZE_OVERFLOW:	Checks whether a buffer size of type `hsize_t' is too
+ *			large to be represented by the `size_t' type.
+ *
+ * REGION_OVERFLOW:	Checks whether an address and size pair describe data
+ *			which can be addressed entirely by the second
+ *			argument of the file seek function.
+ */
+#define MAXADDR (((haddr_t)1<<(8*sizeof(file_offset_t)-1))-1)
+#define ADDR_OVERFLOW(A)	(HADDR_UNDEF==(A) ||			      \
+				 ((A) & ~(haddr_t)MAXADDR))
+#define SIZE_OVERFLOW(Z)	((Z) & ~(hsize_t)MAXADDR)
+#define REGION_OVERFLOW(A,Z)	(ADDR_OVERFLOW(A) || SIZE_OVERFLOW(Z) ||      \
+                                 HADDR_UNDEF==(A)+(Z) ||		      \
+				 (file_offset_t)((A)+(Z))<(file_offset_t)(A))
+
+/* Hard-code file system block size */
+#define FBSIZE		4096	
+
+/* Prototypes */
+static H5FD_t *H5FD_direct_open(const char *name, unsigned flags, hid_t fapl_id,
+			      haddr_t maxaddr);
+static herr_t H5FD_direct_close(H5FD_t *_file);
+static int H5FD_direct_cmp(const H5FD_t *_f1, const H5FD_t *_f2);
+static herr_t H5FD_direct_query(const H5FD_t *_f1, unsigned long *flags);
+static haddr_t H5FD_direct_get_eoa(const H5FD_t *_file);
+static herr_t H5FD_direct_set_eoa(H5FD_t *_file, haddr_t addr);
+static haddr_t H5FD_direct_get_eof(const H5FD_t *_file);
+static herr_t  H5FD_direct_get_handle(H5FD_t *_file, hid_t fapl, void** file_handle);
+static herr_t H5FD_direct_read(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
+			     size_t size, void *buf);
+static herr_t H5FD_direct_write(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
+			      size_t size, const void *buf);
+static herr_t H5FD_direct_flush(H5FD_t *_file, hid_t dxpl_id, unsigned closing);
+
+static const H5FD_class_t H5FD_direct_g = {
+    "direct",					/*name			*/
+    MAXADDR,					/*maxaddr		*/
+    H5F_CLOSE_WEAK,				/* fc_degree		*/
+    NULL,					/*sb_size		*/
+    NULL,					/*sb_encode		*/
+    NULL,					/*sb_decode		*/
+    0, 						/*fapl_size		*/
+    NULL,					/*fapl_get		*/
+    NULL,					/*fapl_copy		*/
+    NULL, 					/*fapl_free		*/
+    0,						/*dxpl_size		*/
+    NULL,					/*dxpl_copy		*/
+    NULL,					/*dxpl_free		*/
+    H5FD_direct_open,			        /*open			*/
+    H5FD_direct_close,		                /*close			*/
+    H5FD_direct_cmp,			        /*cmp			*/
+    H5FD_direct_query,		                /*query			*/
+    NULL,					/*alloc			*/
+    NULL,					/*free			*/
+    H5FD_direct_get_eoa,			/*get_eoa		*/
+    H5FD_direct_set_eoa, 			/*set_eoa		*/
+    H5FD_direct_get_eof,			/*get_eof		*/
+    H5FD_direct_get_handle,                     /*get_handle            */
+    H5FD_direct_read,				/*read			*/
+    H5FD_direct_write,				/*write			*/
+    H5FD_direct_flush,				/*flush 		*/
+    NULL,                                       /*lock                  */
+    NULL,                                       /*unlock                */
+    H5FD_FLMAP_SINGLE 				/*fl_map		*/
+};
+
+/* Declare a free list to manage the H5FD_direct_t struct */
+H5FL_DEFINE_STATIC(H5FD_direct_t);
+
+
+/*--------------------------------------------------------------------------
+NAME
+   H5FD_direct_init_interface -- Initialize interface-specific information
+USAGE
+    herr_t H5FD_direct_init_interface()
+
+RETURNS
+    Non-negative on success/Negative on failure
+DESCRIPTION
+    Initializes any interface-specific data or routines.  (Just calls
+    H5FD_direct_init currently).
+
+--------------------------------------------------------------------------*/
+static herr_t
+H5FD_direct_init_interface(void)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5FD_direct_init_interface)
+
+    FUNC_LEAVE_NOAPI(H5FD_direct_init())
+} /* H5FD_direct_init_interface() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_init
+ *
+ * Purpose:	Initialize this driver by registering the driver with the
+ *		library.
+ *
+ * Return:	Success:	The driver ID for the direct driver.
+ *
+ *		Failure:	Negative.
+ *
+ * Programmer:	Raymond Lu
+ *              Wednesday, 20 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5FD_direct_init(void)
+{
+    hid_t ret_value;        /* Return value */
+
+    FUNC_ENTER_NOAPI(H5FD_direct_init, FAIL)
+
+    if (H5I_VFL!=H5I_get_type(H5FD_DIRECT_g))
+        H5FD_DIRECT_g = H5FD_register(&H5FD_direct_g,sizeof(H5FD_class_t));
+
+    /* Set return value */
+    ret_value=H5FD_DIRECT_g;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*---------------------------------------------------------------------------
+ * Function:	H5FD_direct_term
+ *
+ * Purpose:	Shut down the VFD
+ *
+ * Return:	<none>
+ *
+ * Programmer:  Raymond Lu
+ *              Wednesday, 20 September 2006
+ *
+ * Modification:
+ *
+ *---------------------------------------------------------------------------
+ */
+void
+H5FD_direct_term(void)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5FD_direct_term)
+
+    /* Reset VFL ID */
+    H5FD_DIRECT_g=0;
+
+    FUNC_LEAVE_NOAPI_VOID
+} /* end H5FD_direct_term() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5Pset_fapl_direct
+ *
+ * Purpose:	Modify the file access property list to use the H5FD_DIRECT
+ *		driver defined in this source file.  There are no driver
+ *		specific properties.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Raymond Lu
+ *		Wednesday, 20 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_fapl_direct(hid_t fapl_id)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    herr_t ret_value;
+
+    FUNC_ENTER_API(H5Pset_fapl_direct, FAIL)
+    H5TRACE1("e","i",fapl_id);
+
+    if(NULL == (plist = H5P_object_verify(fapl_id,H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file access property list")
+
+    ret_value= H5P_set_driver(plist, H5FD_DIRECT, NULL);
+
+done:
+    FUNC_LEAVE_API(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_open
+ *
+ * Purpose:	Create and/or opens a Unix file for direct I/O as an HDF5 file.
+ *
+ * Return:	Success:	A pointer to a new file data structure. The
+ *				public fields will be initialized by the
+ *				caller, which is always H5FD_open().
+ *
+ *		Failure:	NULL
+ *
+ * Programmer:	Raymond Lu
+ *              Wednesday, 20 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static H5FD_t *
+H5FD_direct_open(const char *name, unsigned flags, hid_t UNUSED fapl_id,
+	       haddr_t maxaddr)
+{
+    int			o_flags;
+    int			fd=(-1);
+    H5FD_direct_t	*file=NULL;
+#ifdef WIN32
+    HFILE 		filehandle;
+    struct _BY_HANDLE_FILE_INFORMATION fileinfo;
+#endif
+    h5_stat_t		sb;
+    H5FD_t		*ret_value;
+
+    FUNC_ENTER_NOAPI(H5FD_direct_open, NULL)
+
+    /* Sanity check on file offsets */
+    assert(sizeof(file_offset_t)>=sizeof(size_t));
+
+    /* Check arguments */
+    if (!name || !*name)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "invalid file name")
+    if (0==maxaddr || HADDR_UNDEF==maxaddr)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, NULL, "bogus maxaddr")
+    if (ADDR_OVERFLOW(maxaddr))
+        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, NULL, "bogus maxaddr")
+
+    /* Build the open flags */
+    o_flags = (H5F_ACC_RDWR & flags) ? O_RDWR : O_RDONLY;
+    if (H5F_ACC_TRUNC & flags) o_flags |= O_TRUNC;
+    if (H5F_ACC_CREAT & flags) o_flags |= O_CREAT;
+    if (H5F_ACC_EXCL & flags) o_flags |= O_EXCL;
+
+    /* Flag for Direct I/O */
+    o_flags |= O_DIRECT;
+
+    /* Open the file */
+    if ((fd=HDopen(name, o_flags, 0666))<0)
+        HSYS_GOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open file")
+
+    if (HDfstat(fd, &sb)<0)
+        HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, NULL, "unable to fstat file")
+
+    /* Create the new file struct */
+    if (NULL==(file=H5FL_CALLOC(H5FD_direct_t)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "unable to allocate file struct")
+
+    file->fd = fd;
+    H5_ASSIGN_OVERFLOW(file->eof,sb.st_size,h5_stat_size_t,haddr_t);
+    file->pos = HADDR_UNDEF;
+    file->op = OP_UNKNOWN;
+#ifdef WIN32
+    filehandle = _get_osfhandle(fd);
+    (void)GetFileInformationByHandle((HANDLE)filehandle, &fileinfo);
+    file->fileindexhi = fileinfo.nFileIndexHigh;
+    file->fileindexlo = fileinfo.nFileIndexLow;
+#else
+    file->device = sb.st_dev;
+#ifdef H5_VMS
+    file->inode[0] = sb.st_ino[0];
+    file->inode[1] = sb.st_ino[1];
+    file->inode[2] = sb.st_ino[2];
+#else
+    file->inode = sb.st_ino;
+#endif /*H5_VMS*/
+
+#endif
+
+    /* Set return value */
+    ret_value=(H5FD_t*)file;
+
+done:
+    if(ret_value==NULL) {
+        if(fd>=0)
+            HDclose(fd);
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_close
+ *
+ * Purpose:	Closes the file.
+ *
+ * Return:	Success:	0
+ *
+ *		Failure:	-1, file not closed.
+ *
+ * Programmer:	Raymond Lu
+ *              Wednesday, 20 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_direct_close(H5FD_t *_file)
+{
+    H5FD_direct_t	*file = (H5FD_direct_t*)_file;
+    herr_t      	ret_value=SUCCEED;       /* Return value */
+
+    FUNC_ENTER_NOAPI(H5FD_direct_close, FAIL)
+
+    if (HDclose(file->fd)<0)
+        HSYS_GOTO_ERROR(H5E_IO, H5E_CANTCLOSEFILE, FAIL, "unable to close file")
+
+    H5FL_FREE(H5FD_direct_t,file);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_cmp
+ *
+ * Purpose:	Compares two files belonging to this driver using an
+ *		arbitrary (but consistent) ordering.
+ *
+ * Return:	Success:	A value like strcmp()
+ *
+ *		Failure:	never fails (arguments were checked by the
+ *				caller).
+ *
+ * Programmer:	Raymond Lu
+ *              Thursday, 21 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5FD_direct_cmp(const H5FD_t *_f1, const H5FD_t *_f2)
+{
+    const H5FD_direct_t	*f1 = (const H5FD_direct_t*)_f1;
+    const H5FD_direct_t	*f2 = (const H5FD_direct_t*)_f2;
+    int ret_value=0;
+
+    FUNC_ENTER_NOAPI(H5FD_direct_cmp, H5FD_VFD_DEFAULT)
+
+#ifdef WIN32
+    if (f1->fileindexhi < f2->fileindexhi) HGOTO_DONE(-1)
+    if (f1->fileindexhi > f2->fileindexhi) HGOTO_DONE(1)
+
+    if (f1->fileindexlo < f2->fileindexlo) HGOTO_DONE(-1)
+    if (f1->fileindexlo > f2->fileindexlo) HGOTO_DONE(1)
+
+#else
+#ifdef H5_DEV_T_IS_SCALAR
+    if (f1->device < f2->device) HGOTO_DONE(-1)
+    if (f1->device > f2->device) HGOTO_DONE(1)
+#else /* H5_DEV_T_IS_SCALAR */
+    /* If dev_t isn't a scalar value on this system, just use memcmp to
+     * determine if the values are the same or not.  The actual return value
+     * shouldn't really matter...
+     */
+    if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t))<0) HGOTO_DONE(-1)
+    if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t))>0) HGOTO_DONE(1)
+#endif /* H5_DEV_T_IS_SCALAR */
+
+#ifndef H5_VMS
+    if (f1->inode < f2->inode) HGOTO_DONE(-1)
+    if (f1->inode > f2->inode) HGOTO_DONE(1)
+#else
+    if(HDmemcmp(&(f1->inode),&(f2->inode),3*sizeof(ino_t))<0) HGOTO_DONE(-1)
+    if(HDmemcmp(&(f1->inode),&(f2->inode),3*sizeof(ino_t))>0) HGOTO_DONE(1)
+#endif /*H5_VMS*/
+
+#endif
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_query
+ *
+ * Purpose:	Set the flags that this VFL driver is capable of supporting.
+ *              (listed in H5FDpublic.h)
+ *
+ * Return:	Success:	non-negative
+ *
+ *		Failure:	negative
+ *
+ * Programmer:	Raymond Lu
+ *              Thursday, 21 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_direct_query(const H5FD_t UNUSED * _f, unsigned long *flags /* out */)
+{
+    herr_t ret_value=SUCCEED;
+
+    FUNC_ENTER_NOAPI(H5FD_direct_query, FAIL)
+
+    /* Set the VFL feature flags that this driver supports */
+    if(flags) {
+        *flags = 0;
+        *flags|=H5FD_FEAT_AGGREGATE_METADATA; /* OK to aggregate metadata allocations */
+        *flags|=H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
+        *flags|=H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
+        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
+    }
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_get_eoa
+ *
+ * Purpose:	Gets the end-of-address marker for the file. The EOA marker
+ *		is the first address past the last byte allocated in the
+ *		format address space.
+ *
+ * Return:	Success:	The end-of-address marker.
+ *
+ *		Failure:	HADDR_UNDEF
+ *
+ * Programmer:	Raymond Lu
+ *              Wednesday, 20 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static haddr_t
+H5FD_direct_get_eoa(const H5FD_t *_file)
+{
+    const H5FD_direct_t	*file = (const H5FD_direct_t*)_file;
+    haddr_t ret_value;  /* Return value */
+
+    FUNC_ENTER_NOAPI(H5FD_direct_get_eoa, HADDR_UNDEF)
+
+    /* Set return value */
+    ret_value=file->eoa;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_set_eoa
+ *
+ * Purpose:	Set the end-of-address marker for the file. This function is
+ *		called shortly after an existing HDF5 file is opened in order
+ *		to tell the driver where the end of the HDF5 data is located.
+ *
+ * Return:	Success:	0
+ *
+ *		Failure:	-1
+ *
+ * Programmer:	Raymond Lu
+ *              Wednesday, 20 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_direct_set_eoa(H5FD_t *_file, haddr_t addr)
+{
+    H5FD_direct_t	*file = (H5FD_direct_t*)_file;
+    herr_t ret_value=SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(H5FD_direct_set_eoa, FAIL)
+
+    file->eoa = addr;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_get_eof
+ *
+ * Purpose:	Returns the end-of-file marker, which is the greater of
+ *		either the Unix end-of-file or the HDF5 end-of-address
+ *		markers.
+ *
+ * Return:	Success:	End of file address, the first address past
+ *				the end of the "file", either the Unix file
+ *				or the HDF5 file.
+ *
+ *		Failure:	HADDR_UNDEF
+ *
+ * Programmer:	Raymond Lu
+ *              Wednesday, 20 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static haddr_t
+H5FD_direct_get_eof(const H5FD_t *_file)
+{
+    const H5FD_direct_t	*file = (const H5FD_direct_t*)_file;
+    haddr_t ret_value;  /* Return value */
+
+    FUNC_ENTER_NOAPI(H5FD_direct_get_eof, HADDR_UNDEF)
+
+    /* Set return value */
+    ret_value=MAX(file->eof, file->eoa);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:       H5FD_diect_get_handle
+ *
+ * Purpose:        Returns the file handle of direct file driver.
+ *
+ * Returns:        Non-negative if succeed or negative if fails.
+ *
+ * Programmer:     Raymond Lu
+ *                 21 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_direct_get_handle(H5FD_t *_file, hid_t UNUSED fapl, void** file_handle)
+{
+    H5FD_direct_t       *file = (H5FD_direct_t *)_file;
+    herr_t              ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI(H5FD_direct_get_handle, FAIL)
+
+    if(!file_handle)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "file handle not valid")
+    *file_handle = &(file->fd);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_read
+ *
+ * Purpose:	Reads SIZE bytes of data from FILE beginning at address ADDR
+ *		into buffer BUF according to data transfer properties in
+ *		DXPL_ID.
+ *
+ * Return:	Success:	Zero. Result is stored in caller-supplied
+ *				buffer BUF.
+ *
+ *		Failure:	-1, Contents of buffer BUF are undefined.
+ *
+ * Programmer:	Raymond Lu
+ *              Thursday, 21 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_direct_read(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, haddr_t addr,
+	       size_t size, void *buf/*out*/)
+{
+    H5FD_direct_t	*file = (H5FD_direct_t*)_file;
+    ssize_t		nbytes;
+    size_t		alloc_size, mem_page_size;
+    void		*copy_buf, *p1, *p2;
+    herr_t      	ret_value=SUCCEED;       /* Return value */
+
+    FUNC_ENTER_NOAPI(H5FD_direct_read, FAIL)
+
+    assert(file && file->pub.cls);
+    assert(buf);
+
+    /* Check for overflow conditions */
+    if (HADDR_UNDEF==addr)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "addr undefined")
+    if (REGION_OVERFLOW(addr, size))
+        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow")
+    if (addr+size>file->eoa)
+        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow")
+
+    /* memory page size needed for the Direct IO option. Make a bigger
+     * buffer for aligned I/O. */
+    mem_page_size = getpagesize();
+    alloc_size = (size / FBSIZE + 1) * FBSIZE + FBSIZE;
+    if (posix_memalign(&copy_buf, mem_page_size, alloc_size) != 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "posix_memalign failed")
+    memset(copy_buf, 0, alloc_size);
+
+    /* look for the aligned position for reading the data */
+    if(file_seek(file->fd, (file_offset_t)(addr - addr % FBSIZE), SEEK_SET) < 0)	
+    	HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
+
+    /*
+     * Read the aligned data in file first, being careful of interrupted system calls, 
+     * partial results, and the end of the file.
+     */
+    p1 = copy_buf;
+    while(alloc_size > 0) {
+        do {
+            nbytes = HDread(file->fd, p1, alloc_size);
+        } while(-1==nbytes && EINTR==errno);
+
+        if (-1==nbytes) /* error */
+            HSYS_GOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "file read failed")
+        if (0==nbytes) {
+            /* end of file but not end of format address space */
+            break;
+        } else {
+            assert(nbytes>0);
+            assert((size_t)nbytes<=alloc_size);
+            H5_CHECK_OVERFLOW(nbytes,ssize_t,size_t);
+            H5_CHECK_OVERFLOW(nbytes,ssize_t,haddr_t);
+            alloc_size -= (size_t)nbytes;
+            p1 = (unsigned char*)p1 + nbytes;
+	}
+    }
+
+    /*look for the right position to copy the data and copy the data 
+     *to the original buffer.*/
+    p2 = (unsigned char*)copy_buf + addr % FBSIZE;
+    memcpy(buf, p2, size);
+
+    /*update address and buffer*/
+    addr += (haddr_t)size;
+    buf = (unsigned char*)buf + size;
+
+    /* Update current position */
+    file->pos = addr;
+    file->op = OP_READ;
+
+    if(((addr % FBSIZE != 0) || (size % FBSIZE != 0)) && copy_buf)
+	HDfree(copy_buf);
+
+done:
+    if(ret_value<0) {
+        /* Reset last file I/O information */
+        file->pos = HADDR_UNDEF;
+        file->op = OP_UNKNOWN;
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_write
+ *
+ * Purpose:	Writes SIZE bytes of data to FILE beginning at address ADDR
+ *		from buffer BUF according to data transfer properties in
+ *		DXPL_ID.
+ *
+ * Return:	Success:	Zero
+ *
+ *		Failure:	-1
+ *
+ * Programmer:	Raymond Lu
+ *              Thursday, 21 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_direct_write(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, haddr_t addr,
+		size_t size, const void *buf)
+{
+    H5FD_direct_t	*file = (H5FD_direct_t*)_file;
+    ssize_t		nbytes;
+    size_t		alloc_size, mem_page_size, dup_size;
+    void		*copy_buf, *p1, *p2;
+    herr_t      	ret_value=SUCCEED;       /* Return value */
+
+    FUNC_ENTER_NOAPI(H5FD_direct_write, FAIL)
+
+    assert(file && file->pub.cls);
+    assert(buf);
+
+    /* Check for overflow conditions */
+    if (HADDR_UNDEF==addr)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "addr undefined")
+    if (REGION_OVERFLOW(addr, size))
+        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow")
+    if (addr+size>file->eoa)
+        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow")
+
+    /* memory page size needed for the Direct IO option. Make a 
+     * bigger buffer for aligned I/O 
+     */
+    mem_page_size = getpagesize();
+    alloc_size = (size / FBSIZE + 1) * FBSIZE + FBSIZE;
+    if (posix_memalign(&copy_buf, mem_page_size, alloc_size) != 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "posix_memalign failed")
+    memset(copy_buf, 0, alloc_size);
+
+    /* look for the right position for reading the data */
+    if(file_seek(file->fd, (file_offset_t)(addr - addr % FBSIZE), SEEK_SET) < 0)	
+	HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
+
+    /*
+     * Read the aligned data first, being careful of interrupted system calls, 
+     * partial results, and the end of the file.
+     */
+    p2 = copy_buf;
+    dup_size = alloc_size;
+    while(dup_size > 0) {
+        do {
+    	    nbytes = read(file->fd, p2, dup_size);
+        } while (-1==nbytes && EINTR==errno);
+        if (-1==nbytes) /* error */
+            HSYS_GOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "file read failed")
+        if (0==nbytes) {
+            /* end of file but not end of format address space */
+            break;
+        } else {
+            assert(nbytes>0);
+            assert((size_t)nbytes<=dup_size);
+            H5_CHECK_OVERFLOW(nbytes,ssize_t,size_t);
+            H5_CHECK_OVERFLOW(nbytes,ssize_t,haddr_t);
+            dup_size -= (size_t)nbytes;
+            p2 = (unsigned char*)p2 + nbytes;
+	}
+    }
+
+    /*append or copy the data to be written to the aligned buffer.*/
+    p1 = (unsigned char*)copy_buf + addr % FBSIZE;
+    memcpy(p1, buf, size);
+
+    /*look for the aligned position for writing the data*/
+    if(file_seek(file->fd, (file_offset_t)(addr - addr % FBSIZE), SEEK_SET) < 0)
+	HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
+
+    /*
+     * Write the data, being careful of interrupted system calls and partial write.  
+     * It doesn't truncate the extra data introduced by alignment because that step 
+     * is done in H5FD_direct_flush.
+     */
+    p2 = copy_buf;
+    while (alloc_size>0) {
+        do {
+	    nbytes = HDwrite(file->fd, p2, alloc_size);
+        } while (-1==nbytes && EINTR==errno);
+
+        if (-1==nbytes) { /* error */
+            HSYS_GOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "file write failed")
+	}
+        assert(nbytes>0);
+        assert((size_t)nbytes<=alloc_size);
+        H5_CHECK_OVERFLOW(nbytes,ssize_t,size_t);
+        H5_CHECK_OVERFLOW(nbytes,ssize_t,haddr_t);
+        alloc_size -= (size_t)nbytes;
+    	p2 = (unsigned char*)p2 + nbytes;
+    }
+
+    /*Update the address and size*/
+    addr += (haddr_t)size;
+    buf = (const char*)buf + size;
+
+    /* Update current position and eof */
+    file->pos = addr;
+    file->op = OP_WRITE;
+    if (file->pos>file->eof)
+        file->eof = file->pos;
+
+    if(((addr % FBSIZE != 0) || (size % FBSIZE != 0)) && copy_buf)
+	HDfree(copy_buf);
+
+done:
+    if(ret_value<0) {
+        /* Reset last file I/O information */
+        file->pos = HADDR_UNDEF;
+        file->op = OP_UNKNOWN;
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FD_direct_flush
+ *
+ * Purpose:	Makes sure that the true file size is the same (or larger)
+ *		than the end-of-address.
+ *
+ * Return:	Success:	Non-negative
+ *
+ *		Failure:	Negative
+ *
+ * Programmer:	Raymond Lu
+ *              Thursday, 21 September 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_direct_flush(H5FD_t *_file, hid_t UNUSED dxpl_id, unsigned UNUSED closing)
+{
+    H5FD_direct_t	*file = (H5FD_direct_t*)_file;
+    herr_t      	ret_value=SUCCEED;       /* Return value */
+
+    FUNC_ENTER_NOAPI(H5FD_direct_flush, FAIL)
+
+    assert(file);
+
+    /* Extend the file to make sure it's large enough */
+    if (file->eoa!=file->eof) {
+#ifdef WIN32
+        HFILE filehandle;   /* Windows file handle */
+        LARGE_INTEGER li;   /* 64-bit integer for SetFilePointer() call */
+
+        /* Map the posix file handle to a Windows file handle */
+        filehandle = _get_osfhandle(file->fd);
+
+        /* Translate 64-bit integers into form Windows wants */
+        /* [This algorithm is from the Windows documentation for SetFilePointer()] */
+        li.QuadPart = (LONGLONG)file->eoa;
+        (void)SetFilePointer((HANDLE)filehandle,li.LowPart,&li.HighPart,FILE_BEGIN);
+        if(SetEndOfFile((HANDLE)filehandle)==0)
+            HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
+#else /* WIN32 */
+        if (-1==file_truncate(file->fd, (file_offset_t)file->eoa))
+            HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
+#endif /* WIN32 */
+
+        /* Update the eof value */
+        file->eof = file->eoa;
+
+        /* Reset last file I/O information */
+        file->pos = HADDR_UNDEF;
+        file->op = OP_UNKNOWN;
+    } else { 
+	/*Even though eof is equal to eoa, file is still truncated because Direct I/O
+	 *write introduces some extra data for alignment.
+	 */
+        if (-1==file_truncate(file->fd, (file_offset_t)file->eof))
+            HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
+    }
+    
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+#endif /* H5_HAVE_DIRECT */
diff --git a/src/H5FDdirect.h b/src/H5FDdirect.h
new file mode 100644
index 0000000..25ff3de
--- /dev/null
+++ b/src/H5FDdirect.h
@@ -0,0 +1,47 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Programmer:  Raymond Lu <slu@hdfgroup.uiuc.edu>
+ *              Wednesday, 20 September 2006
+ *
+ * Purpose:	The public header file for the direct driver.
+ */
+#ifndef H5FDdirect_H
+#define H5FDdirect_H
+
+#include "H5Ipublic.h"
+
+#ifdef H5_HAVE_DIRECT
+#       define H5FD_DIRECT	(H5FD_direct_init())
+#else
+#       define H5FD_DIRECT      (-1)
+#endif /* H5_HAVE_DIRECT */
+
+#ifdef H5_HAVE_DIRECT
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+H5_DLL hid_t H5FD_direct_init(void);
+H5_DLL void H5FD_direct_term(void);
+H5_DLL herr_t H5Pset_fapl_direct(hid_t fapl_id);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* H5_HAVE_DIRECT */
+
+#endif
diff --git a/src/H5FLprivate.h b/src/H5FLprivate.h
index 8297fe9..1a4f065 100644
--- a/src/H5FLprivate.h
+++ b/src/H5FLprivate.h
@@ -35,7 +35,7 @@
 /* Private headers needed by this file */
 
 /* Macros for turning off free lists in the library */
-/* #define H5_NO_FREE_LISTS */
+/*#define H5_NO_FREE_LISTS*/
 #if defined H5_NO_FREE_LISTS || defined H5_USING_PURIFY
 #define H5_NO_REG_FREE_LISTS
 #define H5_NO_ARR_FREE_LISTS
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index c0659d3..168a156 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -445,7 +445,7 @@ typedef struct H5F_t H5F_t;
 #define H5F_ACS_FAMILY_NEWSIZE_SIZE            sizeof(hsize_t)
 #define H5F_ACS_FAMILY_NEWSIZE_DEF             0
 
-/* Definition for whether to conver family to sec2 driver. It's private
+/* Definition for whether to convert family to sec2 driver. It's private
  * property only used by h5repart */
 #define H5F_ACS_FAMILY_TO_SEC2_NAME            "family_to_sec2"
 #define H5F_ACS_FAMILY_TO_SEC2_SIZE            sizeof(hbool_t)
diff --git a/src/H5Lexternal.c b/src/H5Lexternal.c
index 878abfc..4ca5c83 100644
--- a/src/H5Lexternal.c
+++ b/src/H5Lexternal.c
@@ -138,9 +138,9 @@ H5L_extern_traverse(const char UNUSED *link_name, hid_t cur_group,
     if(H5Fclose(fid) < 0)
         goto error;
 
-    /* Open the external file */
     if((fid = H5Fopen(file_name, intent, fapl_id)) < 0)
         goto error;
+
     ret_value = H5Oopen(fid, obj_name, lapl_id); /* If this fails, our return value will be negative. */
     if(H5Pclose(fapl_id) < 0)
         goto error;
diff --git a/src/H5config.h.in b/src/H5config.h.in
index 756553d..0853964 100644
--- a/src/H5config.h.in
+++ b/src/H5config.h.in
@@ -54,6 +54,9 @@
 /* Define to 1 if you have the `difftime' function. */
 #undef HAVE_DIFFTIME
 
+/* Define if the direct I/O virtual file driver should be compiled */
+#undef HAVE_DIRECT
+
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #undef HAVE_DLFCN_H
 
diff --git a/src/Makefile.am b/src/Makefile.am
index 3076db5..d37c4bc 100755
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -47,7 +47,7 @@ libhdf5_la_SOURCES= H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5Defl.c H5Dio.c H5Distore.c H5Dmpio.c H5Doh.c H5Dselect.c H5Dtest.c \
         H5E.c H5F.c \
         H5Fdbg.c H5Ffake.c H5Fmount.c H5Fsfile.c H5Fsuper.c H5FD.c H5FDcore.c  \
-        H5FDfamily.c H5FDlog.c H5FDmpi.c H5FDmpio.c   \
+        H5FDdirect.c H5FDfamily.c H5FDlog.c H5FDmpi.c H5FDmpio.c   \
         H5FDmpiposix.c H5FDmulti.c H5FDsec2.c H5FDstdio.c           \
         H5FDstream.c H5FL.c H5FO.c H5FS.c H5FScache.c H5FSdbg.c H5FSsection.c \
         H5G.c H5Gbtree2.c H5Gdense.c H5Gdeprec.c H5Gent.c H5Glink.c H5Gloc.c \
@@ -76,8 +76,8 @@ libhdf5_la_SOURCES= H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
 # Public headers
 include_HEADERS =H5public.h H5Apublic.h H5ACpublic.h \
         H5Cpublic.h H5Dpublic.h  \
-        H5Epubgen.h H5Epublic.h H5Fpublic.h H5FDpublic.h H5FDcore.h H5FDfamily.h          \
-        H5FDlog.h H5FDmpi.h H5FDmpio.h H5FDmpiposix.h              \
+        H5Epubgen.h H5Epublic.h H5Fpublic.h H5FDpublic.h H5FDcore.h H5FDdirect.h \
+	H5FDfamily.h H5FDlog.h H5FDmpi.h H5FDmpio.h H5FDmpiposix.h              \
         H5FDmulti.h H5FDsec2.h  H5FDstdio.h H5FDstream.h \
         H5Gpublic.h  H5Ipublic.h H5Lpublic.h \
         H5MMpublic.h H5Opublic.h H5Ppublic.h H5Rpublic.h H5Spublic.h \
diff --git a/src/Makefile.in b/src/Makefile.in
index 3a4c51b..728290e 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -89,7 +89,7 @@ am_libhdf5_la_OBJECTS = H5.lo H5checksum.lo H5dbg.lo H5system.lo \
 	H5Defl.lo H5Dio.lo H5Distore.lo H5Dmpio.lo H5Doh.lo \
 	H5Dselect.lo H5Dtest.lo H5E.lo H5F.lo H5Fdbg.lo H5Ffake.lo \
 	H5Fmount.lo H5Fsfile.lo H5Fsuper.lo H5FD.lo H5FDcore.lo \
-	H5FDfamily.lo H5FDlog.lo H5FDmpi.lo H5FDmpio.lo \
+	H5FDdirect.lo H5FDfamily.lo H5FDlog.lo H5FDmpi.lo H5FDmpio.lo \
 	H5FDmpiposix.lo H5FDmulti.lo H5FDsec2.lo H5FDstdio.lo \
 	H5FDstream.lo H5FL.lo H5FO.lo H5FS.lo H5FScache.lo H5FSdbg.lo \
 	H5FSsection.lo H5G.lo H5Gbtree2.lo H5Gdense.lo H5Gdeprec.lo \
@@ -398,7 +398,7 @@ libhdf5_la_SOURCES = H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5Defl.c H5Dio.c H5Distore.c H5Dmpio.c H5Doh.c H5Dselect.c H5Dtest.c \
         H5E.c H5F.c \
         H5Fdbg.c H5Ffake.c H5Fmount.c H5Fsfile.c H5Fsuper.c H5FD.c H5FDcore.c  \
-        H5FDfamily.c H5FDlog.c H5FDmpi.c H5FDmpio.c   \
+        H5FDdirect.c H5FDfamily.c H5FDlog.c H5FDmpi.c H5FDmpio.c   \
         H5FDmpiposix.c H5FDmulti.c H5FDsec2.c H5FDstdio.c           \
         H5FDstream.c H5FL.c H5FO.c H5FS.c H5FScache.c H5FSdbg.c H5FSsection.c \
         H5G.c H5Gbtree2.c H5Gdense.c H5Gdeprec.c H5Gent.c H5Glink.c H5Gloc.c \
@@ -427,8 +427,8 @@ libhdf5_la_SOURCES = H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
 # Public headers
 include_HEADERS = H5public.h H5Apublic.h H5ACpublic.h \
         H5Cpublic.h H5Dpublic.h  \
-        H5Epubgen.h H5Epublic.h H5Fpublic.h H5FDpublic.h H5FDcore.h H5FDfamily.h          \
-        H5FDlog.h H5FDmpi.h H5FDmpio.h H5FDmpiposix.h              \
+        H5Epubgen.h H5Epublic.h H5Fpublic.h H5FDpublic.h H5FDcore.h H5FDdirect.h \
+	H5FDfamily.h H5FDlog.h H5FDmpi.h H5FDmpio.h H5FDmpiposix.h              \
         H5FDmulti.h H5FDsec2.h  H5FDstdio.h H5FDstream.h \
         H5Gpublic.h  H5Ipublic.h H5Lpublic.h \
         H5MMpublic.h H5Opublic.h H5Ppublic.h H5Rpublic.h H5Spublic.h \
@@ -581,6 +581,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5F.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5FD.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5FDcore.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5FDdirect.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5FDfamily.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5FDlog.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5FDmpi.Plo@am__quote@
diff --git a/src/hdf5.h b/src/hdf5.h
index cf3d762..a3ae138 100644
--- a/src/hdf5.h
+++ b/src/hdf5.h
@@ -47,5 +47,6 @@
 #include "H5FDsec2.h"		/* POSIX unbuffered file I/O		*/
 #include "H5FDstdio.h"		/* Standard C buffered I/O		*/
 #include "H5FDstream.h"     	/* In-memory files streamed via sockets */
+#include "H5FDdirect.h"     	/* Linux direct I/O			*/
 
 #endif