[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, 14 insertions, 1 deletions

diff --git a/src/H5FDcore.c b/src/H5FDcore.c
index a08abdd..bd77199 100644
--- a/src/H5FDcore.c
+++ b/src/H5FDcore.c
@@ -53,6 +53,9 @@ typedef struct H5FD_core_t {
     hbool_t	backing_store;		/*write to file name on flush	*/
     int		fd;			/*backing store file descriptor	*/
     hbool_t	dirty;			/*changes not saved?		*/
+
+    /* Information from file open flags, for SWMR access */
+    hbool_t     swmr_read;      /* Whether the file is open for SWMR read access */
 } H5FD_core_t;
 
 /* Driver-specific file access properties */
@@ -464,6 +467,10 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
         }
     }
 
+    /* Check for SWMR reader access */
+    if(flags & H5F_ACC_SWMR_READ)
+        file->swmr_read = TRUE;
+
     /* Set return value */
     ret_value=(H5FD_t *)file;
 
@@ -782,7 +789,13 @@ H5FD_core_read(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, hadd
         HGOTO_ERROR(H5E_IO, H5E_OVERFLOW, FAIL, "file address overflowed")
     if (REGION_OVERFLOW(addr, size))
         HGOTO_ERROR(H5E_IO, H5E_OVERFLOW, FAIL, "file address overflowed")
-    if (addr + size > file->eoa)
+    /* 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((addr + size) > file->eoa)
         HGOTO_ERROR(H5E_IO, H5E_OVERFLOW, FAIL, "file address overflowed")
 
     /* Read the part which is before the EOF marker */