[svn-r16960] Description:

	Add a new H5F_ACC_SWMR_WRITE flag for H5Fcreate/H5Fopen, so that an
application can indicate that it is modifying the file in a SWMR scenario and
internal algorithms can make appropriate adjustments to order their I/O
operations to meet the constraints necessary for ensuring SWMR consistency.

Tested on:
        FreeBSD/32 6.3 (duty) in debug mode
        FreeBSD/64 6.3 (liberty) w/C++ & FORTRAN, in debug mode
        Linux/32 2.6 (jam) w/PGI compilers, w/C++ & FORTRAN, w/threadsafe,
                                in debug mode
        Linux/64-amd64 2.6 (smirom) w/Intel compilers w/default API=1.6.x,
                                w/C++ & FORTRAN, in production mode
        Solaris/32 2.10 (linew) w/deprecated symbols disabled, w/C++ & FORTRAN,
                                w/szip filter, in production mode
        Linux/64-ia64 2.6 (cobalt) w/Intel compilers, w/C++ & FORTRAN,
                                in production mode
        Linux/64-ia64 2.4 (tg-login3) w/parallel, w/FORTRAN, in debug mode
        Linux/64-amd64 2.6 (abe) w/parallel, w/FORTRAN, in production mode
        Mac OS X/32 10.5.6 (amazon) in debug mode
        Mac OS X/32 10.5.6 (amazon) w/C++ & FORTRAN, w/threadsafe,
                                in production mode

4 files changed, 153 insertions, 15 deletions

diff --git a/src/H5F.c b/src/H5F.c
index fc85688..a367428 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -1284,7 +1284,8 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id, hid_t d
 	 * file (since we can't do that while the file is open), or if the
 	 * request was to create a non-existent file (since the file already
 	 * exists), or if the new request adds write access (since the
-	 * readers don't expect the file to change under them).
+	 * readers don't expect the file to change under them), or if the
+         * SWMR Write access flags don't agree.
 	 */
 	if(H5FD_close(lf) < 0)
 	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to close low-level file info")
@@ -1294,6 +1295,9 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id, hid_t d
 	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "file exists")
 	if((flags & H5F_ACC_RDWR) && 0 == (shared->flags & H5F_ACC_RDWR))
 	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "file is already open for read-only")
+	if(((flags & H5F_ACC_SWMR_WRITE) && 0 == (shared->flags & H5F_ACC_SWMR_WRITE))
+                || (0 == (flags & H5F_ACC_SWMR_WRITE) && (shared->flags & H5F_ACC_SWMR_WRITE)))
+	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "single-writer access flag not the same for file that is already open")
 
         /* Allocate new "high-level" file struct */
         if((file = H5F_new(shared, fcpl_id, fapl_id, NULL)) == NULL)
@@ -1490,11 +1494,15 @@ H5Fcreate(const char *filename, unsigned flags, hid_t fcpl_id, hid_t fapl_id)
     H5TRACE4("i", "*sIuii", filename, flags, fcpl_id, fapl_id);
 
     /* Check/fix arguments */
-    if (!filename || !*filename)
+    if(!filename || !*filename)
 	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file name")
-    if (flags & ~(H5F_ACC_EXCL|H5F_ACC_TRUNC|H5F_ACC_DEBUG))
+    /* In this routine, we only accept the following flags:
+     *          H5F_ACC_EXCL, H5F_ACC_TRUNC, H5F_ACC_DEBUG and H5F_ACC_SWMR_WRITE
+     */
+    if(flags & ~(H5F_ACC_EXCL | H5F_ACC_TRUNC | H5F_ACC_DEBUG | H5F_ACC_SWMR_WRITE))
 	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid flags")
-    if ((flags & H5F_ACC_EXCL) && (flags & H5F_ACC_TRUNC))
+    /* The H5F_ACC_EXCL and H5F_ACC_TRUNC flags are mutually exclusive */
+    if((flags & H5F_ACC_EXCL) && (flags & H5F_ACC_TRUNC))
 	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "mutually exclusive flags for file creation")
 
     /* Check file creation property list */
@@ -1594,9 +1602,13 @@ H5Fopen(const char *filename, unsigned flags, hid_t fapl_id)
     /* Check/fix arguments. */
     if(!filename || !*filename)
 	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file name")
+    /* Reject undefined flags (~H5F_ACC_PUBLIC_FLAGS) and the H5F_ACC_TRUNC & H5F_ACC_EXCL flags */
     if((flags & ~H5F_ACC_PUBLIC_FLAGS) ||
             (flags & H5F_ACC_TRUNC) || (flags & H5F_ACC_EXCL))
 	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file open flags")
+    /* Asking for SWMR Write access on a read-only file is invalid */
+    if((flags & H5F_ACC_SWMR_WRITE) && 0 == (flags & H5F_ACC_RDWR))
+        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "single-writer access on a file open for read-only is not allowed")
     if(H5P_DEFAULT == fapl_id)
         fapl_id = H5P_FILE_ACCESS_DEFAULT;
     else
@@ -2183,10 +2195,16 @@ H5Fget_intent(hid_t file_id, unsigned *intent_flags)
          * Simplify things for them so that they only get either H5F_ACC_RDWR
          * or H5F_ACC_RDONLY.
          */
-        if(H5F_INTENT(file) & H5F_ACC_RDWR)
+        if(H5F_INTENT(file) & H5F_ACC_RDWR) {
             *intent_flags = H5F_ACC_RDWR;
+
+            /* Check for SWMR Write access on the file */
+            if(H5F_INTENT(file) & H5F_ACC_SWMR_WRITE)
+                *intent_flags |= H5F_ACC_SWMR_WRITE;
+        } /* end if */
         else
             *intent_flags = H5F_ACC_RDONLY;
+
     } /* end if */
 
 done:
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index 49af73e..0d5a593 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -61,7 +61,7 @@
 #define H5F_SUPER_ALL_FLAGS             (H5F_SUPER_WRITE_ACCESS | H5F_SUPER_FILE_OK)
 
 /* Mask for removing private file access flags */
-#define H5F_ACC_PUBLIC_FLAGS 	0x00ffu
+#define H5F_ACC_PUBLIC_FLAGS 	        0x003fu
 
 /* Free space section+aggregator merge flags */
 #define H5F_FS_MERGE_METADATA           0x01    /* Section can merge with metadata aggregator */
diff --git a/src/H5Fpublic.h b/src/H5Fpublic.h
index 287e9b5..cea4ae2 100644
--- a/src/H5Fpublic.h
+++ b/src/H5Fpublic.h
@@ -49,6 +49,15 @@
 #define H5F_ACC_EXCL	(H5CHECK 0x0004u)	/*fail if file already exists*/
 #define H5F_ACC_DEBUG	(H5CHECK 0x0008u)	/*print debug info	     */
 #define H5F_ACC_CREAT	(H5CHECK 0x0010u)	/*create non-existing files  */
+#define H5F_ACC_SWMR_WRITE	(H5CHECK 0x0020u) /*indicate that this file is
+                                                 * open for writing in a
+                                                 * single-writer/multi-reader (SWMR)
+                                                 * scenario.  Note that the
+                                                 * process(es) opening the file
+                                                 * reading shouldn't open the
+                                                 * for RDWR access, although a
+                                                 * special "SWMR_READ" access
+                                                 * flag is not necessary. */
 
 /* Value passed to H5Pset_elink_acc_flags to cause flags to be taken from the
  * parent file. */
diff --git a/test/tfile.c b/test/tfile.c
index 68c7f6b..445f5c2 100644
--- a/test/tfile.c
+++ b/test/tfile.c
@@ -233,7 +233,7 @@ test_file_create(void)
     {
        hid_t       dataset_id, dataspace_id;  /* identifiers */
        hsize_t     dims[F2_RANK];
-       int         data[F2_DIM0][F2_DIM1];
+       unsigned    data[F2_DIM0][F2_DIM1];
        unsigned i,j;
 
        /* Create the data space for the dataset. */
@@ -243,7 +243,7 @@ test_file_create(void)
        CHECK(dataspace_id, FAIL, "H5Screate_simple");
 
        /* Create the dataset. */
-       dataset_id = H5Dcreate2(fid2, F2_DSET, H5T_NATIVE_INT, dataspace_id, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
+       dataset_id = H5Dcreate2(fid2, F2_DSET, H5T_NATIVE_UINT, dataspace_id, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
        CHECK(dataset_id, FAIL, "H5Dcreate2");
 
        for(i = 0; i < F2_DIM0; i++)
@@ -251,7 +251,7 @@ test_file_create(void)
                data[i][j] = i * 10 + j;
 
        /* Write data to the new dataset */
-       ret = H5Dwrite(dataset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, data);
+       ret = H5Dwrite(dataset_id, H5T_NATIVE_UINT, H5S_ALL, H5S_ALL, H5P_DEFAULT, data);
        CHECK(ret, FAIL, "H5Dwrite");
 
        /* End access to the dataset and release resources used by it. */
@@ -804,7 +804,7 @@ create_objects(hid_t fid1, hid_t fid2, hid_t *ret_did, hid_t *ret_gid1,
     {
        hid_t       dataset_id, dataspace_id;  /* identifiers */
        hsize_t     dims[F2_RANK];
-       int         data[F2_DIM0][F2_DIM1];
+       unsigned    data[F2_DIM0][F2_DIM1];
        unsigned    i,j;
 
        /* Create the data space for the dataset. */
@@ -814,7 +814,7 @@ create_objects(hid_t fid1, hid_t fid2, hid_t *ret_did, hid_t *ret_gid1,
        CHECK(dataspace_id, FAIL, "H5Screate_simple");
 
        /* Create the dataset. */
-       dataset_id = H5Dcreate2(fid1, "/dset", H5T_NATIVE_INT, dataspace_id, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
+       dataset_id = H5Dcreate2(fid1, "/dset", H5T_NATIVE_UINT, dataspace_id, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
        CHECK(dataset_id, FAIL, "H5Dcreate2");
 
        for(i = 0; i < F2_DIM0; i++)
@@ -822,8 +822,7 @@ create_objects(hid_t fid1, hid_t fid2, hid_t *ret_did, hid_t *ret_gid1,
                data[i][j] = i * 10 + j;
 
        /* Write data to the new dataset */
-       ret = H5Dwrite(dataset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL,
-                H5P_DEFAULT, data);
+       ret = H5Dwrite(dataset_id, H5T_NATIVE_UINT, H5S_ALL, H5S_ALL, H5P_DEFAULT, data);
        CHECK(ret, FAIL, "H5Dwrite");
 
        if(ret_did != NULL)
@@ -2014,7 +2013,7 @@ test_cached_stab_info(void)
 
     /* Reopen file */
     file_id = H5Fopen(FILE1, H5F_ACC_RDONLY, H5P_DEFAULT);
-    CHECK(ret, FAIL, "H5Fopen");
+    CHECK(file_id, FAIL, "H5Fopen");
 
     /* Verify the cached symbol table information */
     ret = H5F_check_cached_stab_test(file_id);
@@ -2027,6 +2026,117 @@ test_cached_stab_info(void)
 
 /****************************************************************
 **
+**  test_swmr_write(): low-level file test routine.
+**      This test checks that the H5F_ACC_SWMR_WRITE access flag is
+**      working properly.
+**
+*****************************************************************/
+static void
+test_swmr_write(void)
+{
+    hid_t fid, fid2;    /* File IDs */
+    unsigned intent;    /* File access flags */
+    herr_t ret;         /* Generic return value */
+
+    /* Output message about test being performed */
+    MESSAGE(5, ("Testing H5F_ACC_SWMR_WRITE access flag\n"));
+
+
+    /* Create file, without SWMR_WRITE flag */
+    fid = H5Fcreate(FILE1, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+    CHECK(fid, FAIL, "H5Fcreate");
+
+    /* Get the intent & check that the SWMR_WRITE flag is not set */
+    ret = H5Fget_intent(fid, &intent);
+    CHECK(ret, FAIL, "H5Fget_intent");
+    VERIFY(intent, H5F_ACC_RDWR, "H5Fget_intent");
+
+    /* Try to reopen file w/SWMR_WRITE flag */
+    H5E_BEGIN_TRY {
+        fid2 = H5Fopen(FILE1, (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE), H5P_DEFAULT);
+    } H5E_END_TRY;
+    VERIFY(fid2, FAIL, "H5Fopen");
+
+    /* Close file */
+    ret = H5Fclose(fid);
+    CHECK(ret, FAIL, "H5Fclose");
+
+
+    /* Create file, with  SWMR_WRITE flag */
+    fid = H5Fcreate(FILE1, (H5F_ACC_TRUNC | H5F_ACC_SWMR_WRITE), H5P_DEFAULT, H5P_DEFAULT);
+    CHECK(fid, FAIL, "H5Fcreate");
+
+    /* Get the intent & check that the SWMR_WRITE flag is set */
+    ret = H5Fget_intent(fid, &intent);
+    CHECK(ret, FAIL, "H5Fget_intent");
+    VERIFY(intent, (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE), "H5Fget_intent");
+
+    /* Try to reopen file w/o SWMR_WRITE flag */
+    H5E_BEGIN_TRY {
+        fid2 = H5Fopen(FILE1, H5F_ACC_RDWR, H5P_DEFAULT);
+    } H5E_END_TRY;
+    VERIFY(fid2, FAIL, "H5Fopen");
+
+    /* Reopen file, with read-write and SWMR_WRITE access */
+    fid2 = H5Fopen(FILE1, (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE), H5P_DEFAULT);
+    CHECK(fid2, FAIL, "H5Fopen");
+
+    /* Get the intent & check that the SWMR_WRITE flag is set */
+    ret = H5Fget_intent(fid2, &intent);
+    CHECK(ret, FAIL, "H5Fget_intent");
+    VERIFY(intent, (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE), "H5Fget_intent");
+
+    /* Close file */
+    ret = H5Fclose(fid2);
+    CHECK(ret, FAIL, "H5Fclose");
+
+    /* Close file */
+    ret = H5Fclose(fid);
+    CHECK(ret, FAIL, "H5Fclose");
+
+
+    /* Try to reopen file read-only w/SWMR_WRITE flag */
+    H5E_BEGIN_TRY {
+        fid = H5Fopen(FILE1, (H5F_ACC_RDONLY | H5F_ACC_SWMR_WRITE), H5P_DEFAULT);
+    } H5E_END_TRY;
+    VERIFY(fid, FAIL, "H5Fopen");
+
+
+    /* Reopen file, with read-write and SWMR_WRITE access */
+    fid = H5Fopen(FILE1, (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE), H5P_DEFAULT);
+    CHECK(fid, FAIL, "H5Fopen");
+
+    /* Get the intent & check that the SWMR_WRITE flag is set */
+    ret = H5Fget_intent(fid, &intent);
+    CHECK(ret, FAIL, "H5Fget_intent");
+    VERIFY(intent, (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE), "H5Fget_intent");
+
+    /* Try to reopen file w/o SWMR_WRITE flag */
+    H5E_BEGIN_TRY {
+        fid2 = H5Fopen(FILE1, H5F_ACC_RDWR, H5P_DEFAULT);
+    } H5E_END_TRY;
+    VERIFY(fid2, FAIL, "H5Fopen");
+
+    /* Reopen file, with read-write and SWMR_WRITE access */
+    fid2 = H5Fopen(FILE1, (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE), H5P_DEFAULT);
+    CHECK(fid2, FAIL, "H5Fopen");
+
+    /* Get the intent & check that the SWMR_WRITE flag is set */
+    ret = H5Fget_intent(fid2, &intent);
+    CHECK(ret, FAIL, "H5Fget_intent");
+    VERIFY(intent, (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE), "H5Fget_intent");
+
+    /* Close file */
+    ret = H5Fclose(fid2);
+    CHECK(ret, FAIL, "H5Fclose");
+
+    /* Close file */
+    ret = H5Fclose(fid);
+    CHECK(ret, FAIL, "H5Fclose");
+} /* end test_swmr_write() */
+
+/****************************************************************
+**
 **  test_file(): Main low-level file I/O test routine.
 **
 ****************************************************************/
@@ -2058,7 +2168,8 @@ test_file(void)
 #endif /*H5_CANNOT_OPEN_TWICE*/
     test_userblock_file_size(); /* Tests that files created with a userblock have the correct size */
     test_cached_stab_info();    /* Tests that files are created with cached stab info in the superblock */
-}				/* test_file() */
+    test_swmr_write();          /* Tests for SWMR write access flag */
+} /* test_file() */
 
 
 /*-------------------------------------------------------------------------