[svn-r13028] Description:

    Add first pass of "dense" attribute storage to objects.  Lots of parts of
this are stubbed out, but all the tests are passing and I'll work on the corner
cases soon.

    Eliminated several unused parameters from object header message callback
routines.

    Other, miscellaneous code cleanups, etc. (and probably some things I've
forgotten about... :-)

Tested on:
    FreeBSD/32 4.11 (sleipnir)
    Linux/32 2.4 (heping)
    AIX/32 5.? (copper)

1 files changed, 170 insertions, 90 deletions

diff --git a/src/H5Omessage.c b/src/H5Omessage.c
index 32ec4f8..b7bc47d 100644
--- a/src/H5Omessage.c
+++ b/src/H5Omessage.c
@@ -33,6 +33,7 @@
 /* Headers */
 /***********/
 #include "H5private.h"		/* Generic Functions			*/
+#include "H5Aprivate.h"		/* Attributes	  			*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5Fprivate.h"		/* File access				*/
 #include "H5MMprivate.h"	/* Memory management			*/
@@ -76,17 +77,13 @@ typedef struct {
     H5O_operator_t op;          /* Callback routine for removal operations */
     void *op_data;              /* Callback data for removal operations */
     hbool_t adj_link;           /* Whether to adjust links when removing messages */
-} H5O_iter_ud1_t;
+} H5O_iter_rm_t;
 
-/* Typedef for "internal library" iteration operations */
-typedef herr_t (*H5O_lib_operator_t)(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
-    unsigned sequence, unsigned *oh_flags_ptr/*out*/, void *operator_data/*in,out*/);
-
-/* Some syntactic sugar to make the compiler happy with two different kinds of iterator callbacks */
-typedef union {
-    H5O_operator_t app_op;      /* Application callback for each message */
-    H5O_lib_operator_t lib_op;  /* Library internal callback for each message */
-} H5O_mesg_operator_t;
+/* User data for iteration when converting attributes to dense storage */
+typedef struct {
+    H5F_t      *f;              /* Pointer to file for insertion */
+    hid_t dxpl_id;              /* DXPL during iteration */
+} H5O_iter_to_dense_t;
 
 
 /********************/
@@ -100,7 +97,7 @@ typedef union {
 
 static herr_t H5O_msg_write_real(H5F_t *f, H5O_t *oh, const H5O_msg_class_t *type,
     unsigned overwrite, unsigned mesg_flags, unsigned update_flags,
-    const void *mesg, unsigned *oh_flags_ptr, hid_t dxpl_id);
+    const void *mesg, hid_t dxpl_id, unsigned *oh_flags_ptr);
 static herr_t H5O_msg_reset_real(const H5O_msg_class_t *type, void *native);
 static void *H5O_msg_copy_real(const H5O_msg_class_t *type, const void *mesg,
         void *dst);
@@ -108,8 +105,6 @@ static herr_t H5O_msg_remove_real(const H5O_loc_t *loc, const H5O_msg_class_t *t
     int sequence, H5O_operator_t op, void *op_data, hbool_t adj_link, hid_t dxpl_id);
 static herr_t H5O_msg_remove_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/, 
     unsigned sequence, unsigned *oh_flags_ptr, void *_udata/*in,out*/);
-static herr_t H5O_msg_iterate_real(const H5O_loc_t *loc, const H5O_msg_class_t *type,
-    H5AC_protect_t prot, hbool_t internal, H5O_mesg_operator_t op, void *op_data, hid_t dxpl_id);
 static unsigned H5O_new_mesg(H5F_t *f, H5O_t *oh, unsigned *flags,
     const H5O_msg_class_t *orig_type, const void *orig_mesg, H5O_shared_t *sh_mesg,
     const H5O_msg_class_t **new_type, const void **new_mesg, hid_t dxpl_id,
@@ -188,6 +183,49 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5O_msg_attr_to_dense_cb
+ *
+ * Purpose:	Object header iterator callback routine to convert compact
+ *              attributes to dense attributes
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Dec  4 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_msg_attr_to_dense_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
+    unsigned UNUSED sequence, unsigned *oh_flags_ptr, void *_udata/*in,out*/)
+{
+    H5O_iter_to_dense_t *udata = (H5O_iter_to_dense_t *)_udata;   /* Operator user data */
+    herr_t ret_value = H5_ITER_CONT;   /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5O_msg_attr_to_dense_cb)
+
+    /* check args */
+    HDassert(oh);
+    HDassert(mesg);
+
+    /* Insert attribute into dense storage */
+    if(H5A_dense_insert(udata->f, udata->dxpl_id, oh, mesg->flags, mesg->native) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, H5_ITER_ERROR, "unable to add to dense storage")
+
+    /* Convert message into a null message */
+    if(H5O_release_mesg(udata->f, udata->dxpl_id, oh, mesg, TRUE, FALSE) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, H5_ITER_ERROR, "unable to convert into null message")
+
+    /* Indicate that the object header was modified */
+    *oh_flags_ptr |= H5AC__DIRTIED_FLAG;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_msg_attr_to_dense_cb() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5O_msg_append
  *
  * Purpose:	Simplified version of H5O_msg_create, used when creating a new
@@ -213,8 +251,9 @@ H5O_msg_append(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned type_id,
     const H5O_msg_class_t *new_type;    /* Actual H5O class type for the ID */
     const void *new_mesg;               /* Actual message to write */
     const H5O_msg_class_t *type;        /* Original H5O class type for the ID */
-    H5O_shared_t	sh_mesg;        /* Shared object header info */
-    unsigned		idx;            /* Index of message to modify */
+    H5O_shared_t sh_mesg;               /* Shared object header info */
+    unsigned idx;                       /* Index of message to modify */
+    hbool_t new_format_attr;            /* Whether this message is an attribute in a new-format header */
     htri_t shared_mesg;                 /* Should this message be stored in the Shared Message table? */
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -237,23 +276,64 @@ H5O_msg_append(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned type_id,
     else if(shared_mesg < 0)
 	HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "error determining if message should be shared")
 
-    /* If the message added is an attribute, increment count */
-    if(H5O_ATTR_ID == type_id && oh->version > H5O_VERSION_1) {
+    /* Set the flag for an attribute in a new format header */
+    if(H5O_ATTR_ID == type_id && oh->version > H5O_VERSION_1)
+        new_format_attr = TRUE;
+    else
+        new_format_attr = FALSE;
+
+    /* If the message added is an attribute, check for dense storage */
+    if(new_format_attr) {
 #ifdef QAK
 HDfprintf(stderr, "%s: adding attribute to new-style object header\n", FUNC);
+HDfprintf(stderr, "%s: oh->nattrs = %Hu\n", FUNC, oh->nattrs);
+HDfprintf(stderr, "%s: oh->max_compact = %u\n", FUNC, oh->max_compact);
+HDfprintf(stderr, "%s: oh->min_dense = %u\n", FUNC, oh->min_dense);
+#endif /* QAK */
+        /* Check for switching to "dense" attribute storage */
+        if(oh->nattrs == oh->max_compact && !H5F_addr_defined(oh->attr_fheap_addr)) {
+            H5O_iter_to_dense_t udata;          /* User data for callback */
+            H5O_mesg_operator_t op;             /* Wrapper for operator */
+#ifdef QAK
+HDfprintf(stderr, "%s: converting attributes to dense storage\n", FUNC);
 #endif /* QAK */
+
+            /* Create dense storage for attributes */
+            if(H5A_dense_create(f, dxpl_id, oh) < 0)
+                HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to create dense storage for attributes")
+
+            /* Set up user data for callback */
+            udata.f = f;
+            udata.dxpl_id = dxpl_id;
+
+            /* Iterate over existing attributes, moving them to dense storage */
+            op.lib_op = H5O_msg_attr_to_dense_cb;
+            if(H5O_msg_iterate_real(f, oh, H5O_MSG_ATTR, TRUE, op, &udata, dxpl_id, oh_flags_ptr) < 0)
+                HGOTO_ERROR(H5E_OHDR, H5E_CANTCONVERT, FAIL, "error converting attributes to dense storage")
+        } /* end if */
     } /* end if */
 
-    /* Create a new message */
-    if((idx = H5O_new_mesg(f, oh, &mesg_flags, type, mesg, &sh_mesg, &new_type, &new_mesg, dxpl_id, oh_flags_ptr)) == UFAIL)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to create new message")
+    /* Check for storing attribute with dense storage */
+    if(new_format_attr && H5F_addr_defined(oh->attr_fheap_addr)) {
+        /* Insert attribute into dense storage */
+#ifdef QAK
+HDfprintf(stderr, "%s: inserting attribute to dense storage\n", FUNC);
+#endif /* QAK */
+        if(H5A_dense_insert(f, dxpl_id, oh, mesg_flags, mesg) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "unable to add to dense storage")
+    } /* end if */
+    else {
+        /* Create a new message */
+        if((idx = H5O_new_mesg(f, oh, &mesg_flags, type, mesg, &sh_mesg, &new_type, &new_mesg, dxpl_id, oh_flags_ptr)) == UFAIL)
+            HGOTO_ERROR(H5E_OHDR, H5E_NOSPACE, FAIL, "unable to create new message")
 
-    /* Write the information to the message */
-    if(H5O_write_mesg(f, dxpl_id, oh, idx, new_type, new_mesg, mesg_flags, update_flags, oh_flags_ptr) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to write message")
+        /* Write the information to the message */
+        if(H5O_write_mesg(f, dxpl_id, oh, idx, new_type, new_mesg, mesg_flags, update_flags, oh_flags_ptr) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to write message")
+    } /* end else */
 
     /* If the message added is an attribute, increment count */
-    if(H5O_ATTR_ID == type_id && oh->version > H5O_VERSION_1)
+    if(new_format_attr)
         oh->nattrs++;
 #ifdef H5O_DEBUG
 H5O_assert(oh);
@@ -307,6 +387,7 @@ H5O_msg_write(H5O_loc_t *loc, unsigned type_id, unsigned overwrite,
     HDassert(loc);
     HDassert(loc->file);
     HDassert(H5F_addr_defined(loc->addr));
+    HDassert(H5O_ATTR_ID != type_id);   /* Attributes are modified in another routine */
     HDassert(type_id < NELMTS(H5O_msg_class_g));
     type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
     HDassert(type);
@@ -329,8 +410,8 @@ H5O_msg_write(H5O_loc_t *loc, unsigned type_id, unsigned overwrite,
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")
 
     /* Call the "real" modify routine */
-    if(H5O_msg_write_real(loc->file, oh, type, overwrite, mesg_flags, update_flags, mesg, &oh_flags, dxpl_id) < 0)
-	HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "unable to write object header message")
+    if(H5O_msg_write_real(loc->file, oh, type, overwrite, mesg_flags, update_flags, mesg, dxpl_id, &oh_flags) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "unable to write object header message")
 
 done:
     if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
@@ -368,12 +449,12 @@ done:
 static herr_t
 H5O_msg_write_real(H5F_t *f, H5O_t *oh, const H5O_msg_class_t *type,
     unsigned overwrite, unsigned mesg_flags, unsigned update_flags,
-    const void *mesg, unsigned *oh_flags_ptr, hid_t dxpl_id)
+    const void *mesg, hid_t dxpl_id, unsigned *oh_flags_ptr)
 {
     int	        	sequence;       /* Sequence # of message type to modify */
     unsigned		idx;            /* Index of message to modify */
     H5O_mesg_t         *idx_msg;        /* Pointer to message to modify */
-    H5O_shared_t	sh_mesg;
+    H5O_shared_t	sh_mesg;        /* Shared message to store */
     const H5O_msg_class_t *write_type = type;   /* Type of message to be written */
     const void          *write_mesg = mesg;     /* Actual message being written */
     herr_t	        ret_value = SUCCEED;    /* Return value */
@@ -409,12 +490,11 @@ H5O_msg_write_real(H5F_t *f, H5O_t *oh, const H5O_msg_class_t *type,
          * First, make sure it's not a committed message; these can't ever
          * be modified.
          */
-        if(((H5O_shared_t *)oh->mesg[idx].native)->flags & H5O_COMMITTED_FLAG)
-            HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "unable to modify committed message")
+        HDassert(!(((H5O_shared_t *)oh->mesg[idx].native)->flags & H5O_COMMITTED_FLAG));
 
         /* Remove the old message from the SOHM index */
         if(H5SM_try_delete(f, dxpl_id, oh->mesg[idx].type->id, oh->mesg[idx].native) < 0)
-            HGOTO_ERROR (H5E_OHDR, H5E_CANTFREE, FAIL, "unable to delete message from SOHM table")
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to delete message from SOHM table")
 
         /* Now this message is no longer shared and we can safely overwrite it.
          * We need to make sure that the message we're writing is shared,
@@ -429,7 +509,7 @@ H5O_msg_write_real(H5F_t *f, H5O_t *oh, const H5O_msg_class_t *type,
 
         /* Extract shared message info from current message */
         if(H5O_msg_get_share(type->id, mesg, &sh_mesg) < 0)
-              HGOTO_ERROR (H5E_OHDR, H5E_BADMESG, FAIL, "can't get shared message")
+            HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, FAIL, "can't get shared message")
 
         /* Instead of writing the original message, write a shared message */
         write_type = H5O_MSG_SHARED;
@@ -472,7 +552,8 @@ done:
  *-------------------------------------------------------------------------
  */
 void *
-H5O_msg_read(const H5O_loc_t *loc, unsigned type_id, int sequence, void *mesg, hid_t dxpl_id)
+H5O_msg_read(const H5O_loc_t *loc, unsigned type_id, int sequence, void *mesg,
+    hid_t dxpl_id)
 {
     H5O_t *oh = NULL;                   /* Object header to use */
     void *ret_value;                    /* Return value */
@@ -575,7 +656,7 @@ H5O_msg_read_real(H5F_t *f, H5O_t *oh, unsigned type_id, int sequence,
 	 * the raw message) so we must copy the native message before
 	 * returning.
 	 */
-	if(NULL == (ret_value = (type->copy)(oh->mesg[idx].native, mesg, 0)))
+	if(NULL == (ret_value = (type->copy)(oh->mesg[idx].native, mesg)))
 	    HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "unable to copy message to user space")
     } /* end else */
 
@@ -823,7 +904,7 @@ H5O_msg_copy_real(const H5O_msg_class_t *type, const void *mesg, void *dst)
     HDassert(type->copy);
 
     if(mesg)
-	if(NULL == (ret_value = (type->copy)(mesg, dst, 0)))
+	if(NULL == (ret_value = (type->copy)(mesg, dst)))
 	    HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "unable to copy object header message")
 
 done:
@@ -847,7 +928,7 @@ done:
  *-------------------------------------------------------------------------
  */
 int
-H5O_msg_count(H5O_loc_t *loc, unsigned type_id, hid_t dxpl_id)
+H5O_msg_count(const H5O_loc_t *loc, unsigned type_id, hid_t dxpl_id)
 {
     H5O_t *oh = NULL;           /* Object header to operate on */
     const H5O_msg_class_t *type;        /* Actual H5O class type for the ID */
@@ -1088,7 +1169,7 @@ static herr_t
 H5O_msg_remove_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/, unsigned sequence,
     unsigned *oh_flags_ptr, void *_udata/*in,out*/)
 {
-    H5O_iter_ud1_t *udata = (H5O_iter_ud1_t *)_udata;   /* Operator user data */
+    H5O_iter_rm_t *udata = (H5O_iter_rm_t *)_udata;   /* Operator user data */
     htri_t try_remove = FALSE;         /* Whether to try removing a message */
     herr_t ret_value = H5_ITER_CONT;   /* Return value */
 
@@ -1106,7 +1187,7 @@ H5O_msg_remove_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/, unsigned sequence,
     else {
         /* If there's no callback routine, does the sequence # match? */
         if((int)sequence == udata->sequence || H5O_ALL == udata->sequence)
-            try_remove = H5_ITER_STOP;
+            try_remove = TRUE;
     } /* end else */
 
     /* Try removing the message, if indicated */
@@ -1164,9 +1245,11 @@ static herr_t
 H5O_msg_remove_real(const H5O_loc_t *loc, const H5O_msg_class_t *type, int sequence,
     H5O_operator_t app_op, void *op_data, hbool_t adj_link, hid_t dxpl_id)
 {
-    H5O_iter_ud1_t udata;               /* User data for iterator */
+    H5O_t *oh = NULL;                   /* Pointer to actual object header */
+    unsigned oh_flags = H5AC__NO_FLAGS_SET;  /* Start iteration with no flags set on object header */
+    H5O_iter_rm_t udata;                /* User data for iterator */
     H5O_mesg_operator_t op;             /* Wrapper for operator */
-    herr_t ret_value=SUCCEED;           /* Return value */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5O_msg_remove_real)
 
@@ -1188,16 +1271,23 @@ H5O_msg_remove_real(const H5O_loc_t *loc, const H5O_msg_class_t *type, int seque
     udata.op_data = op_data;
     udata.adj_link = adj_link;
 
+    /* Protect the object header to iterate over */
+    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
+	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")
+
     /* Iterate over the messages, deleting appropriate one(s) */
     op.lib_op = H5O_msg_remove_cb;
-    if(H5O_msg_iterate_real(loc, type, H5AC_WRITE, TRUE, op, &udata, dxpl_id) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "error iterating over messages")
+    if(H5O_msg_iterate_real(loc->file, oh, type, TRUE, op, &udata, dxpl_id, &oh_flags) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_NOTFOUND, FAIL, "error iterating over messages")
 
     /* Fail if we tried to remove any constant messages */
     if(udata.nfailed)
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to remove constant message(s)")
 
 done:
+    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
+        HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5O_msg_remove_real() */
 
@@ -1217,7 +1307,7 @@ done:
  *
  * Description:
  *      This function interates over the object headers of an object
- *  specified with 'ent' of type 'type_id'.  For each object header of the
+ *  specified with 'loc' of type 'type_id'.  For each object header of the
  *  object, the 'op_data' and some additional information (specified below) are
  *  passed to the 'op' function.
  *      The operation receives a pointer to the object header message for the
@@ -1237,6 +1327,8 @@ herr_t
 H5O_msg_iterate(const H5O_loc_t *loc, unsigned type_id, H5O_operator_t app_op,
     void *op_data, hid_t dxpl_id)
 {
+    H5O_t *oh = NULL;               /* Pointer to actual object header */
+    unsigned oh_flags = H5AC__NO_FLAGS_SET;  /* Start iteration with no flags set on object header */
     const H5O_msg_class_t *type;    /* Actual H5O class type for the ID */
     H5O_mesg_operator_t op;         /* Wrapper for operator */
     herr_t ret_value;               /* Return value */
@@ -1251,12 +1343,19 @@ H5O_msg_iterate(const H5O_loc_t *loc, unsigned type_id, H5O_operator_t app_op,
     type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
     HDassert(type);
 
+    /* Protect the object header to iterate over */
+    if(NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, H5AC_WRITE)))
+	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")
+
     /* Call the "real" iterate routine */
     op.app_op = app_op;
-    if((ret_value = H5O_msg_iterate_real(loc, type, H5AC_READ, FALSE, op, op_data, dxpl_id)) < 0)
-	HGOTO_ERROR(H5E_OHDR, H5E_BADITER, FAIL, "unable to iterate over object header messages")
+    if((ret_value = H5O_msg_iterate_real(loc->file, oh, type, FALSE, op, op_data, dxpl_id, &oh_flags)) < 0)
+        HERROR(H5E_OHDR, H5E_BADITER, "unable to iterate over object header messages");
 
 done:
+    if(oh && H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
+        HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5O_msg_iterate() */
 
@@ -1292,53 +1391,44 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5O_msg_iterate_real(const H5O_loc_t *loc, const H5O_msg_class_t *type, H5AC_protect_t prot,
-    hbool_t internal, H5O_mesg_operator_t op, void *op_data, hid_t dxpl_id)
+herr_t
+H5O_msg_iterate_real(H5F_t *f, H5O_t *oh, const H5O_msg_class_t *type,
+    hbool_t internal, H5O_mesg_operator_t op, void *op_data, hid_t dxpl_id,
+    unsigned *oh_flags_ptr)
 {
-    H5O_t		*oh = NULL;     /* Pointer to actual object header */
-    unsigned            oh_flags = H5AC__NO_FLAGS_SET;  /* Start iteration with no flags set on object header */
     unsigned		idx;            /* Absolute index of current message in all messages */
     unsigned		sequence;       /* Relative index of current message for messages of type */
     H5O_mesg_t         *idx_msg;        /* Pointer to current message */
     void               *native_mesg;    /* Native, readable message */
     hbool_t             native_mesg_alloc = FALSE;  /* True if native_mesg needs to be freed */
-
     herr_t              ret_value = H5_ITER_CONT;      /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5O_msg_iterate_real)
 
     /* check args */
-    HDassert(loc);
-    HDassert(loc->file);
-    HDassert(H5F_addr_defined(loc->addr));
+    HDassert(f);
+    HDassert(oh);
     HDassert(type);
     HDassert(op.app_op);
-
-    /* Protect the object header to iterate over */
-    if (NULL == (oh = H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, NULL, NULL, prot)))
-	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")
+    HDassert(oh_flags_ptr);
 
     /* Iterate over messages */
     for(sequence = 0, idx = 0, idx_msg = &oh->mesg[0]; idx < oh->nmesgs && !ret_value; idx++, idx_msg++) {
 	if(type->id == idx_msg->type->id) {
-
-            /*
-             * Decode the message if necessary.
-             */
-            H5O_LOAD_NATIVE(loc->file, dxpl_id, idx_msg, FAIL)
+            /* Decode the message if necessary.  */
+            H5O_LOAD_NATIVE(f, dxpl_id, idx_msg, FAIL)
 
             /* Check for making an "internal" (i.e. within the H5O package) callback */
             if(internal) {
                 /* Call the "internal" iterator callback */
-                if((ret_value = (op.lib_op)(oh, idx_msg, sequence, &oh_flags, op_data)) != 0)
+                if((ret_value = (op.lib_op)(oh, idx_msg, sequence, oh_flags_ptr, op_data)) != 0)
                     break;
             } /* end if */
             else {
                 /* If the message is shared, get the real message it points to */
                 /* JAMES: test */
                 if(idx_msg->flags & H5O_MSG_FLAG_SHARED) {
-                    if(NULL == (native_mesg = H5O_shared_read(loc->file, dxpl_id,
+                    if(NULL == (native_mesg = H5O_shared_read(f, dxpl_id,
                                 idx_msg->native, idx_msg->type, NULL)))
                         HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, FAIL, "unable to read shared message")
                     native_mesg_alloc = TRUE;
@@ -1371,27 +1461,18 @@ done:
     if(native_mesg_alloc)
         H5O_msg_free(idx_msg->type->id, native_mesg);
 
-    /* Object header cleanup */
-    if(oh) {
-        /* Check if object header was modified */
-        if(oh_flags & H5AC__DIRTIED_FLAG) {
-            /* Shouldn't be able to modify object header if we don't have write access */
-            HDassert(prot == H5AC_WRITE);
-
-            /* Try to condense object header info */
-            /* (Since this routine is invoked when a message is removed from
-             *  an object header, the header will be condensed after each
-             *  message removal)
-             */
-            if(H5O_condense_header(loc->file, oh, dxpl_id) < 0)
-                HDONE_ERROR(H5E_OHDR, H5E_CANTPACK, FAIL, "can't pack object header")
-
-            if(H5O_touch_oh(loc->file, dxpl_id, oh, FALSE, &oh_flags) < 0)
-                HDONE_ERROR(H5E_OHDR, H5E_CANTUPDATE, FAIL, "unable to update time on object")
-        } /* end if */
+    /* Check if object message was modified */
+    if(*oh_flags_ptr & H5AC__DIRTIED_FLAG) {
+        /* Try to condense object header info */
+        /* (Since this routine is used to remove messages from an
+         *  object header, the header will be condensed after each
+         *  message removal)
+         */
+        if(H5O_condense_header(f, oh, dxpl_id) < 0)
+            HDONE_ERROR(H5E_OHDR, H5E_CANTPACK, FAIL, "can't pack object header")
 
-        if(H5AC_unprotect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, oh, oh_flags) < 0)
-            HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header")
+        if(H5O_touch_oh(f, dxpl_id, oh, FALSE, oh_flags_ptr) < 0)
+            HDONE_ERROR(H5E_OHDR, H5E_CANTUPDATE, FAIL, "unable to update time on object")
     } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1893,18 +1974,17 @@ H5O_write_mesg(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned idx,
     idx_msg = &oh->mesg[idx];
 
     /* Reset existing native information */
-    if(!(update_flags & H5O_UPDATE_DATA_ONLY))
-        H5O_msg_reset_real(type, idx_msg->native);
+    H5O_msg_reset_real(type, idx_msg->native);
 
     /* Copy the native value for the message */
-    if(NULL == (idx_msg->native = (type->copy)(mesg, idx_msg->native, update_flags)))
+    if(NULL == (idx_msg->native = (type->copy)(mesg, idx_msg->native)))
         HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to copy message to object header")
 
     /* Update the message flags and mark the message as modified */
     idx_msg->flags = mesg_flags;
     idx_msg->dirty = TRUE;
 
-    /* Update the modification time message if any */
+    /* Update the modification time, if requested */
     if(update_flags & H5O_UPDATE_TIME)
         if(H5O_touch_oh(f, dxpl_id, oh, FALSE, oh_flags_ptr) < 0)
             HGOTO_ERROR(H5E_OHDR, H5E_CANTUPDATE, FAIL, "unable to update time on object")
@@ -1966,7 +2046,7 @@ H5O_delete_mesg(H5F_t *f, hid_t dxpl_id, H5O_mesg_t *mesg, hbool_t adj_link)
         {
             /* The native message here is actually a shared message.    */
             if(H5SM_try_delete(f, dxpl_id, mesg->type->id, mesg->native) < 0)
-                HGOTO_ERROR (H5E_OHDR, H5E_CANTFREE, FAIL, "unable to delete message from SOHM table")
+                HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to delete message from SOHM table")
         }
 
         if((type->del)(f, dxpl_id, mesg->native, adj_link) < 0)