[svn-r17638] Description:

	Bring r17624 from trunk to 1.8 branch:

	Don't allow reads to change or add to the metadata accumulator, since
they might be speculative and could bring raw data into the metadata
accumulator.

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/default API=1.8.x,
               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 10.6.1 (amazon) in debug mode
       Mac OS X/32 10.6.1 (amazon) w/C++ & FORTRAN, w/threadsafe,
               in production mode

6 files changed, 80 insertions, 63 deletions

diff --git a/MANIFEST b/MANIFEST
index deead23..a8f573a 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -848,6 +848,7 @@
 ./test/pool.c
 ./test/set_extent.c
 ./test/space_overflow.c			_DO_NOT_DISTRIBUTE_
+./test/specmetaread.h5
 ./test/stab.c
 ./test/tarray.c
 ./test/tarrold.h5
diff --git a/configure b/configure
index 664c7bc..e410924 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Id: configure.in 17548 2009-09-29 16:45:07Z acheng .
+# From configure.in Id: configure.in 17568 2009-10-01 17:06:48Z mamcgree .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.64 for HDF5 1.8.3-snap13.
 #
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index 95f9795..bf71c3c 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -128,6 +128,9 @@ Bug Fixes since HDF5-1.8.3
 
     Library
     -------
+    - Fixed error in library's internal caching mechanisms which could cause
+      an assertion failure (and attendent core dump) when encountering an
+      unusually formatted file.  (QAK - 2009/10/13)
     - Fixed incorrect return value for H5Pget_preserve. AKC - 2009/10/08 - 1628
     - Fixed an assertion failure that occurred when H5Ocopy was called on a
       dataset using a vlen inside a compound. NAF - 2009/10/02 - 1597
diff --git a/src/H5Faccum.c b/src/H5Faccum.c
index d8b9820..e525a08 100644
--- a/src/H5Faccum.c
+++ b/src/H5Faccum.c
@@ -99,6 +99,10 @@ H5FL_BLK_DEFINE_STATIC(meta_accum);
  * Purpose:	Attempts to read some data from the metadata accumulator for
  *              a file into a buffer.
  *
+ * Note:	We can't change (or add to) the metadata accumulator, because
+ *		this might be a speculative read and could possibly read raw
+ *		data into the metadata accumulator.
+ *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
@@ -185,69 +189,11 @@ H5F_accum_read(const H5F_t *f, hid_t dxpl_id, H5FD_mem_t type, haddr_t addr,
             /* Make certain we've read it all */
             HDassert(size == 0);
         } /* end if */
-        /* Current read doesn't overlap with metadata accumulator, read it into accumulator */
+        /* Current read doesn't overlap with metadata accumulator, read it from file */
         else {
-            /* Only update the metadata accumulator if it is not dirty or if
-             * we are allowed to write the accumulator out during reads (when
-             * it is dirty)
-             */
-            if(f->shared->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA_READ || !f->shared->accum.dirty) {
-                /* Flush current contents, if dirty */
-                if(f->shared->accum.dirty) {
-                    if(H5FD_write(f->shared->lf, dxpl_id, H5FD_MEM_DEFAULT, f->shared->accum.loc, f->shared->accum.size, f->shared->accum.buf) < 0)
-                        HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "driver write request failed")
-
-                    /* Reset accumulator dirty flag */
-                    f->shared->accum.dirty = FALSE;
-                } /* end if */
-
-                /* Cache the new piece of metadata */
-                /* Check if we need to resize the buffer */
-                if(size > f->shared->accum.alloc_size) {
-                    size_t new_size;        /* New size of accumulator */
-
-                    /* Adjust the buffer size to be a power of 2 that is large enough to hold data */
-                    new_size = (size_t)1 << (1 + H5V_log2_gen((uint64_t)(size - 1)));
-
-                    /* Grow the metadata accumulator buffer */
-                    if(NULL == (f->shared->accum.buf = H5FL_BLK_REALLOC(meta_accum, f->shared->accum.buf, new_size)))
-                        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate metadata accumulator buffer")
-
-                    /* Note the new buffer size */
-                    f->shared->accum.alloc_size = new_size;
-                } /* end if */
-                else {
-                    /* Check if we should shrink the accumulator buffer */
-                    if(size < (f->shared->accum.alloc_size / H5F_ACCUM_THROTTLE) &&
-                            f->shared->accum.alloc_size > H5F_ACCUM_THRESHOLD) {
-                        size_t new_size = (f->shared->accum.alloc_size / H5F_ACCUM_THROTTLE); /* New size of accumulator buffer */
-
-                        /* Shrink the accumulator buffer */
-                        if(NULL == (f->shared->accum.buf = H5FL_BLK_REALLOC(meta_accum, f->shared->accum.buf, new_size)))
-                            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate metadata accumulator buffer")
-
-                        /* Note the new buffer size */
-                        f->shared->accum.alloc_size = new_size;
-                    } /* end if */
-                } /* end else */
-
-                /* Update accumulator information */
-                f->shared->accum.loc = addr;
-                f->shared->accum.size = size;
-                f->shared->accum.dirty = FALSE;
-
-                /* Read into accumulator */
-                if(H5FD_read(f->shared->lf, dxpl_id, H5FD_MEM_DEFAULT, f->shared->accum.loc, f->shared->accum.size, f->shared->accum.buf) < 0)
-                    HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "driver read request failed")
-
-                /* Copy into buffer */
-                HDmemcpy(buf, f->shared->accum.buf, size);
-            } /* end if */
-            else {
-                /* Dispatch to driver */
-                if(H5FD_read(f->shared->lf, dxpl_id, type, addr, size, buf) < 0)
-                    HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "driver read request failed")
-            } /* end else */
+            /* Dispatch to driver */
+            if(H5FD_read(f->shared->lf, dxpl_id, type, addr, size, buf) < 0)
+                HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "driver read request failed")
         } /* end else */
 
         /* Indicate success */
diff --git a/test/specmetaread.h5 b/test/specmetaread.h5
new file mode 100644
index 0000000..50b0e69
--- /dev/null
+++ b/test/specmetaread.h5
diff --git a/test/tmisc.c b/test/tmisc.c
index b646a69..005e77a 100644
--- a/test/tmisc.c
+++ b/test/tmisc.c
@@ -32,6 +32,9 @@
 #include "testhdf5.h"
 #include "H5Dpkg.h"		/* Datasets 				*/
 
+#define NAME_BUF_SIZE   1024
+#define READ_OLD_BUFSIZE        1024
+
 /* Definitions for misc. test #1 */
 #define MISC1_FILE	"tmisc1.h5"
 #define MISC1_VAL       (13417386)      /* 0xccbbaa */
@@ -305,6 +308,11 @@ unsigned m13_rdata[MISC13_DIM1][MISC13_DIM2];          /* Data read from dataset
 #define MISC28_SIZE             10
 #define MISC28_NSLOTS           10000
 
+/* Definitions for misc. test #29 */
+#define MISC29_ORIG_FILE        "specmetaread.h5"
+#define MISC29_COPY_FILE        "tmisc29.h5"
+#define MISC29_DSETNAME         "dset2"
+
 /****************************************************************
 **
 **  test_misc1(): test unlinking a dataset from a group and immediately
@@ -5118,6 +5126,63 @@ test_misc28(void)
     CHECK_I(ret, "H5Pclose");
 } /* end test_misc28() */
 
+
+/****************************************************************
+**
+**  test_misc29(): Ensure that speculative metadata reads don't
+**                 get raw data into the metadata accumulator.
+**
+****************************************************************/
+static void
+test_misc29(void)
+{
+    int	fd_old = (-1), fd_new = (-1);   /* File descriptors for copying data */
+    char  buf[READ_OLD_BUFSIZE];        /* Buffer for copying data */
+    ssize_t nread;                      /* Number of bytes read in */
+    char  *srcdir = HDgetenv("srcdir"); /* where the src code is located */
+    char  filename[NAME_BUF_SIZE] = ""; /* old test file name */
+    hid_t fid;              /* File ID */
+    herr_t  ret;            /* Generic return value */
+
+    /* Output message about test being performed */
+    MESSAGE(5, ("Speculative metadata reads\n"));
+
+    /* Generate correct name for test file by prepending the source path */
+    if(srcdir && ((HDstrlen(srcdir) + HDstrlen(MISC29_ORIG_FILE) + 1) < sizeof(filename))) {
+        HDstrcpy(filename, srcdir);
+        HDstrcat(filename, "/");
+    } /* end if */
+    HDstrcat(filename, MISC29_ORIG_FILE);
+
+    /* Copy old file into temporary file */
+    fd_old = HDopen(filename, O_RDONLY, 0666);
+    CHECK(fd_old, -1, "HDopen");
+    fd_new = HDopen(MISC29_COPY_FILE, O_RDWR|O_CREAT|O_TRUNC, 0666);
+    CHECK(fd_new, -1, "HDopen");
+
+    /* Copy data */
+    while((nread = HDread(fd_old, buf, (size_t)READ_OLD_BUFSIZE)) > 0)
+        HDwrite(fd_new, buf, (size_t)nread);
+
+    /* Close files */
+    ret = HDclose(fd_old);
+    CHECK(ret, -1, "HDclose");
+    ret = HDclose(fd_new);
+    CHECK(ret, -1, "HDclose");
+
+    /* Open the copied file */
+    fid = H5Fopen(MISC29_COPY_FILE, H5F_ACC_RDWR, H5P_DEFAULT); 
+    CHECK(fid, FAIL, "H5Fopen");
+
+    /* Delete the last dataset */
+    ret = H5Ldelete(fid, MISC29_DSETNAME, H5P_DEFAULT);
+    CHECK(ret, FAIL, "H5Ldelete");
+
+    /* Close the file */
+    ret = H5Fclose(fid);
+    CHECK(ret, FAIL, "H5Fclose");
+} /* end test_misc29() */
+
 /****************************************************************
 **
 **  test_misc(): Main misc. test routine.
@@ -5161,6 +5226,7 @@ test_misc(void)
     test_misc26();      /* Test closing property lists with long filter pipelines */
     test_misc27();      /* Test opening file with object that has bad # of object header messages */
     test_misc28();      /* Test that chunks are cached appropriately */
+    test_misc29();      /* Test that speculative metadata reads are handled correctly */
 
 
 } /* test_misc() */
@@ -5216,5 +5282,6 @@ cleanup_misc(void)
     HDremove(MISC25C_FILE);
     HDremove(MISC26_FILE);
     HDremove(MISC28_FILE);
+    HDremove(MISC29_COPY_FILE);
 }