[svn-r17421] Description:

	Change internal mechanism for disabling EOA checks when the SWMR read
flag is set from setting the EOA to 'maxaddr' to setting a flag in the VFDs
that talk to storage, since setting the EOA to 'maxaddr' causes problems when
using the multi (and family, I think) VFDs.

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, check-vfd
        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 10.5.8 (amazon) in debug mode
        Mac OS X/32 10.5.8 (amazon) w/C++ & FORTRAN, w/threadsafe,
                                in production mode

1 files changed, 16 insertions, 2 deletions

diff --git a/src/H5FDstdio.c b/src/H5FDstdio.c
index 193c576..2070b1a 100644
--- a/src/H5FDstdio.c
+++ b/src/H5FDstdio.c
@@ -111,6 +111,9 @@ typedef struct H5FD_stdio_t {
     DWORD fileindexlo;
     DWORD fileindexhi;
 #endif
+
+    /* Information from file open flags, for SWMR access */
+    hbool_t     swmr_read;      /* Whether the file is open for SWMR read access */
 } H5FD_stdio_t;
 
 #ifdef H5_HAVE_LSEEK64
@@ -410,6 +413,11 @@ H5FD_stdio_open( const char *name, unsigned flags, hid_t fapl_id,
     file->device = sb.st_dev;
     file->inode = sb.st_ino;
 #endif
+
+    /* Check for SWMR reader access */
+    if(flags & H5F_ACC_SWMR_READ)
+        file->swmr_read = 1;
+
     return((H5FD_t*)file);
 }   /* end H5FD_stdio_open() */
 
@@ -789,8 +797,14 @@ H5FD_stdio_read(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr, siz
         H5Epush_ret (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1)
     if (REGION_OVERFLOW(addr, size))
         H5Epush_ret (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1)
-    if (addr+size>file->eoa)
-        H5Epush_ret (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1)
+    /* If the file is open for SWMR read access, allow access to data past
+     * the end of the allocated space (the 'eoa').  This is done because the
+     * eoa stored in the file's superblock might be out of sync with the
+     * objects being written within the file by the application performing
+     * SWMR write operations.
+     */
+    if(!file->swmr_read && (addr + size) > file->eoa)
+        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1)
 
     /* Check easy cases */
     if (0 == size)