[svn-r17365] Description:

	Final merge of changes from sblock_mdc branch back to trunk.  The superblock is now managed by the metadata cache.

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 (kagiso) 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 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, 193 insertions, 696 deletions

diff --git a/src/H5Fsuper.c b/src/H5Fsuper.c
index f5973e9..b0096cb 100644
--- a/src/H5Fsuper.c
+++ b/src/H5Fsuper.c
@@ -26,14 +26,13 @@
 /***********/
 /* Headers */
 /***********/
-#include "H5private.h"		/* Generic Functions			*/
-#include "H5Eprivate.h"		/* Error handling		  	*/
-#include "H5Fpkg.h"             /* File access				*/
-#include "H5FDprivate.h"	/* File drivers				*/
-#include "H5Iprivate.h"		/* IDs			  		*/
-#include "H5MFprivate.h"	/* File memory management		*/
-#include "H5MMprivate.h"	/* Memory management			*/
-#include "H5Pprivate.h"		/* Property lists			*/
+#include "H5private.h"		/* Generic Functions                    */
+#include "H5ACprivate.h"        /* Metadata cache                       */
+#include "H5Eprivate.h"		/* Error handling                       */
+#include "H5Fpkg.h"             /* File access                          */
+#include "H5FDprivate.h"	/* File drivers                         */
+#include "H5Iprivate.h"		/* IDs                                  */
+#include "H5Pprivate.h"		/* Property lists                       */
 #include "H5SMprivate.h"        /* Shared Object Header Messages        */
 
 
@@ -41,61 +40,6 @@
 /* Local Macros */
 /****************/
 
-/* Superblock sizes for various versions */
-#define H5F_SIZEOF_CHKSUM 4     /* Checksum size in the file */
-
-/* Fixed-size portion at the beginning of all superblocks */
-#define H5F_SUPERBLOCK_FIXED_SIZE ( H5F_SIGNATURE_LEN                   \
-        + 1) /* superblock version */
-
-/* Macros for computing variable-size superblock size */
-#define H5F_SUPERBLOCK_VARLEN_SIZE_COMMON                               \
-        (2  /* freespace, and root group versions */			\
-        + 1 /* reserved */                                              \
-        + 3 /* shared header vers, size of address, size of lengths */  \
-        + 1 /* reserved */                                              \
-        + 4 /* group leaf k, group internal k */                        \
-        + 4) /* consistency flags */
-#define H5F_SUPERBLOCK_VARLEN_SIZE_V0(f)                                \
-        ( H5F_SUPERBLOCK_VARLEN_SIZE_COMMON /* Common variable-length info */ \
-        + H5F_SIZEOF_ADDR(f) /* base address */                         \
-        + H5F_SIZEOF_ADDR(f) /* <unused> */				\
-        + H5F_SIZEOF_ADDR(f) /* EOF address */                          \
-        + H5F_SIZEOF_ADDR(f) /* driver block address */                 \
-        + H5G_SIZEOF_ENTRY(f)) /* root group ptr */
-#define H5F_SUPERBLOCK_VARLEN_SIZE_V1(f)                                \
-        ( H5F_SUPERBLOCK_VARLEN_SIZE_COMMON /* Common variable-length info */ \
-        + 2 /* indexed B-tree internal k */                             \
-        + 2 /* reserved */                                              \
-        + H5F_SIZEOF_ADDR(f) /* base address */                         \
-        + H5F_SIZEOF_ADDR(f) /* <unused> */				\
-        + H5F_SIZEOF_ADDR(f) /* EOF address */                          \
-        + H5F_SIZEOF_ADDR(f) /* driver block address */                 \
-        + H5G_SIZEOF_ENTRY(f)) /* root group ptr */
-#define H5F_SUPERBLOCK_VARLEN_SIZE_V2(f)                                \
-        ( 2 /* size of address, size of lengths */                      \
-        + 1 /* consistency flags */                                     \
-        + H5F_SIZEOF_ADDR(f) /* base address */                         \
-        + H5F_SIZEOF_ADDR(f) /* superblock extension address */         \
-        + H5F_SIZEOF_ADDR(f) /* EOF address */                          \
-        + H5F_SIZEOF_ADDR(f) /* root group object header address */     \
-        + H5F_SIZEOF_CHKSUM) /* superblock checksum (keep this last) */
-#define H5F_SUPERBLOCK_VARLEN_SIZE(v, f) (				\
-        (v == 0 ? H5F_SUPERBLOCK_VARLEN_SIZE_V0(f) : 0)			\
-        + (v == 1 ? H5F_SUPERBLOCK_VARLEN_SIZE_V1(f) : 0)               \
-        + (v == 2 ? H5F_SUPERBLOCK_VARLEN_SIZE_V2(f) : 0))
-
-/* Total size of superblock, depends on superblock version */
-#define H5F_SUPERBLOCK_SIZE(v, f) ( H5F_SUPERBLOCK_FIXED_SIZE           \
-        + H5F_SUPERBLOCK_VARLEN_SIZE(v, f))
-
-/* Driver info block macros */
-#define H5F_DRVINFOBLOCK_HDR_SIZE 16
-
-/* Maximum size of super-block buffers */
-#define H5F_MAX_SUPERBLOCK_SIZE  134
-#define H5F_MAX_DRVINFOBLOCK_SIZE  1024
-
 
 /******************/
 /* Local Typedefs */
@@ -111,9 +55,6 @@
 /* Local Prototypes */
 /********************/
 static herr_t H5F_super_ext_create(H5F_t *f, hid_t dxpl_id, H5O_loc_t *ext_ptr);
-static herr_t H5F_super_ext_open(H5F_t *f, H5O_loc_t *ext_ptr);
-static herr_t H5F_super_ext_write_msg(H5F_t *f, hid_t dxpl_id, void *mesg, unsigned id, hbool_t may_create);
-static herr_t H5F_super_ext_close(H5F_t *f, H5O_loc_t *ext_ptr);
 
 
 /*********************/
@@ -125,6 +66,9 @@ static herr_t H5F_super_ext_close(H5F_t *f, H5O_loc_t *ext_ptr);
 /* Library Private Variables */
 /*****************************/
 
+/* Declare a free list to manage the H5F_super_t struct */
+H5FL_DEFINE(H5F_super_t);
+
 
 /*******************/
 /* Local Variables */
@@ -238,15 +182,17 @@ H5F_super_ext_create(H5F_t *f, hid_t dxpl_id, H5O_loc_t *ext_ptr)
 
     /* Sanity check */
     HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->sblock);
+    HDassert(!H5F_addr_defined(f->shared->sblock->ext_addr));
     HDassert(ext_ptr);
-    HDassert(!H5F_addr_defined(f->shared->extension_addr));
 
     H5O_loc_reset(ext_ptr);
     if(H5O_create(f, dxpl_id, 0, H5P_GROUP_CREATE_DEFAULT, ext_ptr) < 0)
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTCREATE, FAIL, "unable to create superblock extension")
 
     /* Record the address of the superblock extension */
-    f->shared->extension_addr = ext_ptr->addr;
+    f->shared->sblock->ext_addr = ext_ptr->addr;
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -265,8 +211,8 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5F_super_ext_open(H5F_t *f, H5O_loc_t *ext_ptr)
+herr_t
+H5F_super_ext_open(H5F_t *f, haddr_t ext_addr, H5O_loc_t *ext_ptr)
 {
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -274,17 +220,17 @@ H5F_super_ext_open(H5F_t *f, H5O_loc_t *ext_ptr)
 
     /* Sanity check */
     HDassert(f);
+    HDassert(H5F_addr_defined(ext_addr));
     HDassert(ext_ptr);
-    HDassert(H5F_addr_defined(f->shared->extension_addr));
 
     /* Set up "fake" object location for superblock extension */
     H5O_loc_reset(ext_ptr);
     ext_ptr->file = f;
-    ext_ptr->addr = f->shared->extension_addr;
+    ext_ptr->addr = ext_addr;
 
     /* Open the superblock extension object header */
     if(H5O_open(ext_ptr) < 0)
-	HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENFILE, FAIL, "unable to open superblock extension")
+	HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENOBJ, FAIL, "unable to open superblock extension")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -303,7 +249,7 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static herr_t 
+herr_t 
 H5F_super_ext_close(H5F_t *f, H5O_loc_t *ext_ptr)
 {
     herr_t ret_value = SUCCEED;         /* Return value */
@@ -317,7 +263,7 @@ H5F_super_ext_close(H5F_t *f, H5O_loc_t *ext_ptr)
     /* Twiddle the number of open objects to avoid closing the file. */
     f->nopen_objs++;
     if(H5O_close(ext_ptr) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTRELEASE, FAIL, "unable to close superblock extension")
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCLOSEOBJ, FAIL, "unable to close superblock extension")
     f->nopen_objs--;
 
 done:
@@ -345,421 +291,44 @@ done:
 herr_t
 H5F_super_read(H5F_t *f, hid_t dxpl_id)
 {
-    uint8_t             sbuf[H5F_MAX_SUPERBLOCK_SIZE];     /* Buffer for superblock */
-    H5P_genplist_t     *c_plist;            /* File creation property list  */
-    H5F_file_t         *shared;             /* shared part of `file'        */
-    H5FD_t             *lf;                 /* file driver part of `shared' */
-    haddr_t             abs_super_addr;     /* Absolute offset of superblock in file */
-    haddr_t             stored_eoa;         /*relative end-of-addr in file  */
-    haddr_t             eof;                /*end of file address           */
-    size_t              sizeof_addr;        /* Size of offsets in the file (in bytes) */
-    size_t              sizeof_size;        /* Size of lengths in the file (in bytes) */
-    const size_t        fixed_size = H5F_SUPERBLOCK_FIXED_SIZE; /*fixed sizeof superblock   */
-    size_t              variable_size;      /*variable sizeof superblock    */
-    uint8_t            *p;                  /* Temporary pointer into encoding buffer */
-    unsigned            super_vers;         /* Superblock version          */
-    herr_t              ret_value = SUCCEED;
+    H5F_super_t *       sblock = NULL;      /* superblock structure                         */
+    unsigned            sblock_flags = H5AC__NO_FLAGS_SET;       /* flags used in superblock unprotect call      */
+    H5AC_protect_t      rw;                 /* read/write permissions for file              */
+    hbool_t             dirtied = FALSE;    /* Bool for sblock protect call                 */
+    herr_t              ret_value = SUCCEED; /* return value                                */
 
     FUNC_ENTER_NOAPI(H5F_super_read, FAIL)
 
-    /* Short cuts */
-    shared = f->shared;
-    lf = shared->lf;
-
-    /* Get the shared file creation property list */
-    if(NULL == (c_plist = (H5P_genplist_t *)H5I_object(shared->fcpl_id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "can't get property list")
-
     /* Find the superblock */
-    if(HADDR_UNDEF == (abs_super_addr = H5F_locate_signature(lf, dxpl_id)))
+    if(HADDR_UNDEF == (f->shared->super_addr = H5F_locate_signature(f->shared->lf, dxpl_id)))
         HGOTO_ERROR(H5E_FILE, H5E_NOTHDF5, FAIL, "unable to find file signature")
 
-    /* Read fixed-size portion of the superblock */
-    p = sbuf;
-    if(H5FD_set_eoa(lf, H5FD_MEM_SUPER, abs_super_addr + fixed_size) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "set end of space allocation request failed")
-    if(H5FD_read(lf, dxpl_id, H5FD_MEM_SUPER, abs_super_addr, fixed_size, p) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_READERROR, FAIL, "unable to read superblock")
-
-    /* Skip over signature (already checked when locating the superblock) */
-    p += H5F_SIGNATURE_LEN;
-
-    /* Superblock version */
-    super_vers = *p++;
-    if(super_vers > HDF5_SUPERBLOCK_VERSION_LATEST)
-        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad superblock version number")
-    if(H5P_set(c_plist, H5F_CRT_SUPER_VERS_NAME, &super_vers) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set superblock version")
-
-    /* Sanity check */
-    HDassert(((size_t)(p - sbuf)) == fixed_size);
-
-    /* Determine the size of the variable-length part of the superblock */
-    variable_size = H5F_SUPERBLOCK_VARLEN_SIZE(super_vers, f);
-    HDassert(variable_size > 0);
-    HDassert(fixed_size + variable_size <= sizeof(sbuf));
-
-    /* Read in variable-sized portion of superblock */
-    if(H5FD_set_eoa(lf, H5FD_MEM_SUPER, abs_super_addr + fixed_size + variable_size) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "set end of space allocation request failed")
-    if(H5FD_read(lf, dxpl_id, H5FD_MEM_SUPER, abs_super_addr + fixed_size, variable_size, p) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to read superblock")
-
-    /* Check for older version of superblock format */
-    if(super_vers < HDF5_SUPERBLOCK_VERSION_2) {
-        uint32_t	status_flags;	    /* File status flags	   */
-        unsigned        btree_k[H5B_NUM_BTREE_ID];  /* B-tree internal node 'K' values */
-        unsigned        sym_leaf_k;         /* Symbol table leaf node's 'K' value */
-
-        /* Freespace version (hard-wired) */
-        if(HDF5_FREESPACE_VERSION != *p++)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad free space version number")
-
-        /* Root group version number (hard-wired) */
-        if(HDF5_OBJECTDIR_VERSION != *p++)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad object directory version number")
-
-        /* Skip over reserved byte */
-        p++;
-
-        /* Shared header version number (hard-wired) */
-        if(HDF5_SHAREDHEADER_VERSION != *p++)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad shared-header format version number")
-
-        /* Size of file addresses */
-        sizeof_addr = *p++;
-        if(sizeof_addr != 2 && sizeof_addr != 4 &&
-                sizeof_addr != 8 && sizeof_addr != 16 && sizeof_addr != 32)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad byte number in an address")
-        if(H5P_set(c_plist, H5F_CRT_ADDR_BYTE_NUM_NAME, &sizeof_addr) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set byte number in an address")
-        shared->sizeof_addr = sizeof_addr;  /* Keep a local copy also */
-
-        /* Size of file sizes */
-        sizeof_size = *p++;
-        if(sizeof_size != 2 && sizeof_size != 4 &&
-                sizeof_size != 8 && sizeof_size != 16 && sizeof_size != 32)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad byte number for object size")
-        if(H5P_set(c_plist, H5F_CRT_OBJ_BYTE_NUM_NAME, &sizeof_size) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set byte number for object size")
-        shared->sizeof_size = sizeof_size;  /* Keep a local copy also */
-
-        /* Skip over reserved byte */
-        p++;
-
-        /* Various B-tree sizes */
-        UINT16DECODE(p, sym_leaf_k);
-        if(sym_leaf_k == 0)
-            HGOTO_ERROR(H5E_FILE, H5E_BADRANGE, FAIL, "bad symbol table leaf node 1/2 rank")
-        if(H5P_set(c_plist, H5F_CRT_SYM_LEAF_NAME, &sym_leaf_k) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set rank for symbol table leaf nodes")
-        shared->sym_leaf_k = sym_leaf_k;    /* Keep a local copy also */
-
-        /* Need 'get' call to set other array values */
-        if(H5P_get(c_plist, H5F_CRT_BTREE_RANK_NAME, btree_k) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get rank for btree internal nodes")
-        UINT16DECODE(p, btree_k[H5B_SNODE_ID]);
-        if(btree_k[H5B_SNODE_ID] == 0)
-            HGOTO_ERROR(H5E_FILE, H5E_BADRANGE, FAIL, "bad 1/2 rank for btree internal nodes")
-        /*
-         * Delay setting the value in the property list until we've checked
-         * for the indexed storage B-tree internal 'K' value later.
-         */
-
-        /* File status flags (not really used yet) */
-        UINT32DECODE(p, status_flags);
-        HDassert(status_flags <= 255);
-        shared->status_flags = (uint8_t)status_flags;
-        if(shared->status_flags & ~H5F_SUPER_ALL_FLAGS)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad flag value for superblock")
-
-        /*
-         * If the superblock version # is greater than 0, read in the indexed
-         * storage B-tree internal 'K' value
-         */
-        if(super_vers > HDF5_SUPERBLOCK_VERSION_DEF) {
-            UINT16DECODE(p, btree_k[H5B_CHUNK_ID]);
-            /* Reserved bytes are present only in version 1 */
-            if(super_vers == HDF5_SUPERBLOCK_VERSION_1)
-                p += 2;   /* reserved */
-        } /* end if */
-        else
-            btree_k[H5B_CHUNK_ID] = HDF5_BTREE_CHUNK_IK_DEF;
-
-        /* Set the B-tree internal node values, etc */
-        if(H5P_set(c_plist, H5F_CRT_BTREE_RANK_NAME, btree_k) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set rank for btree internal nodes")
-        HDmemcpy(shared->btree_k, btree_k, sizeof(unsigned) * (size_t)H5B_NUM_BTREE_ID);    /* Keep a local copy also */
-
-        /* Remainder of "variable-sized" portion of superblock */
-        H5F_addr_decode(f, (const uint8_t **)&p, &shared->base_addr/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &shared->extension_addr/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &stored_eoa/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &shared->driver_addr/*out*/);
-
-        /* Decode the symbol table entry */
-        if(H5G_root_ent_decode(f, (const uint8_t **)&p) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to read root symbol entry")
-
-        /*
-         * Check if superblock address is different from base address and
-         * adjust base address and "end of address" address if so.
-         */
-        if(!H5F_addr_eq(abs_super_addr, shared->base_addr)) {
-            /* Check if the superblock moved earlier in the file */
-            if(H5F_addr_lt(abs_super_addr, shared->base_addr))
-                stored_eoa -= (shared->base_addr - abs_super_addr);
-            else
-                /* The superblock moved later in the file */
-                stored_eoa += (abs_super_addr - shared->base_addr);
-
-            shared->base_addr = abs_super_addr;
-        } /* end if */
-
-        /* Set the base address for the file in the VFD now, after adjusting
-         *  space for possible offsets of the HDF5 data in the file.
-         */
-        if(H5FD_set_base_addr(lf, shared->base_addr) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to set base address for file driver")
-
-        /* This step is for h5repart tool only. If user wants to change file driver
-         *  from family to sec2 while using h5repart, set the driver address to
-         *  undefined to let the library ignore the family driver information saved
-         *  in the superblock.
-         */
-        if(shared->fam_to_sec2)
-            shared->driver_addr = HADDR_UNDEF;
-
-        /* Decode the optional driver information block */
-        if(H5F_addr_defined(shared->driver_addr)) {
-            uint8_t dbuf[H5F_MAX_DRVINFOBLOCK_SIZE];     /* Buffer for driver info block */
-            char drv_name[9];       /* Name of driver */
-            unsigned drv_vers;      /* Version of driver info block */
-            size_t drv_variable_size; /* Size of variable-length portion of driver info block, in bytes */
-
-            /* Read in fixed-sized portion of driver info block */
-            p = dbuf;
-            if(H5FD_set_eoa(lf, H5FD_MEM_SUPER, shared->driver_addr + H5F_DRVINFOBLOCK_HDR_SIZE) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "set end of space allocation request failed")
-            if(H5FD_read(lf, dxpl_id, H5FD_MEM_SUPER, shared->driver_addr, (size_t)H5F_DRVINFOBLOCK_HDR_SIZE, p) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to read driver information block")
-
-            /* Version number */
-            drv_vers = *p++;
-            if(drv_vers != HDF5_DRIVERINFO_VERSION_0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "bad driver information block version number")
-
-            p += 3; /* reserved bytes */
-
-            /* Driver info size */
-            UINT32DECODE(p, drv_variable_size);
-
-            /* Sanity check */
-            HDassert(H5F_DRVINFOBLOCK_HDR_SIZE + drv_variable_size <= sizeof(dbuf));
-
-            /* Driver name and/or version */
-            HDstrncpy(drv_name, (const char *)p, (size_t)8);
-            drv_name[8] = '\0';
-            p += 8; /* advance past name/version */
-
-            /* Check if driver matches driver information saved. Unfortunately, we can't push this
-             * function to each specific driver because we're checking if the driver is correct.
-             */
-            if(!HDstrncmp(drv_name, "NCSAfami", (size_t)8) && HDstrcmp(lf->cls->name, "family"))
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "family driver should be used")
-            if(!HDstrncmp(drv_name, "NCSAmult", (size_t)8) && HDstrcmp(lf->cls->name, "multi"))
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "multi driver should be used")
-
-            /* Read in variable-sized portion of driver info block */
-            if(H5FD_set_eoa(lf, H5FD_MEM_SUPER, shared->driver_addr + H5F_DRVINFOBLOCK_HDR_SIZE + drv_variable_size) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "set end of space allocation request failed")
-            if(H5FD_read(lf, dxpl_id, H5FD_MEM_SUPER, shared->driver_addr + H5F_DRVINFOBLOCK_HDR_SIZE, drv_variable_size, p) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to read file driver information")
-
-            /* Decode driver information */
-            if(H5FD_sb_decode(lf, drv_name, p) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to decode driver information")
-        } /* end if */
-    } /* end if */
-    else {
-        uint32_t computed_chksum;       /* Computed checksum  */
-        uint32_t read_chksum;           /* Checksum read from file  */
-
-        /* Size of file addresses */
-        sizeof_addr = *p++;
-        if(sizeof_addr != 2 && sizeof_addr != 4 &&
-                sizeof_addr != 8 && sizeof_addr != 16 && sizeof_addr != 32)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad byte number in an address")
-        if(H5P_set(c_plist, H5F_CRT_ADDR_BYTE_NUM_NAME, &sizeof_addr) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set byte number in an address")
-        shared->sizeof_addr = sizeof_addr;  /* Keep a local copy also */
-
-        /* Size of file sizes */
-        sizeof_size = *p++;
-        if(sizeof_size != 2 && sizeof_size != 4 &&
-                sizeof_size != 8 && sizeof_size != 16 && sizeof_size != 32)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad byte number for object size")
-        if(H5P_set(c_plist, H5F_CRT_OBJ_BYTE_NUM_NAME, &sizeof_size) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set byte number for object size")
-        shared->sizeof_size = sizeof_size;  /* Keep a local copy also */
-
-        /* File status flags (not really used yet) */
-        shared->status_flags = *p++;
-        if(shared->status_flags & ~H5F_SUPER_ALL_FLAGS)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad flag value for superblock")
-
-        /* Base, superblock extension, end of file & root group object header addresses */
-        H5F_addr_decode(f, (const uint8_t **)&p, &shared->base_addr/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &shared->extension_addr/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &stored_eoa/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &shared->root_addr/*out*/);
-
-        /* Compute checksum for superblock */
-        computed_chksum = H5_checksum_metadata(sbuf, (size_t)(p - sbuf), 0);
-
-        /* Decode checksum */
-        UINT32DECODE(p, read_chksum);
-
-        /* Verify correct checksum */
-        if(read_chksum != computed_chksum)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "bad checksum on driver information block")
-
-        /*
-         * Check if superblock address is different from base address and
-         * adjust base address and "end of address" address if so.
-         */
-        if(!H5F_addr_eq(abs_super_addr, shared->base_addr)) {
-            /* Check if the superblock moved earlier in the file */
-            if(H5F_addr_lt(abs_super_addr, shared->base_addr))
-                stored_eoa -= (shared->base_addr - abs_super_addr);
-            else
-                /* The superblock moved later in the file */
-                stored_eoa += (abs_super_addr - shared->base_addr);
-
-            shared->base_addr = abs_super_addr;
-        } /* end if */
-
-        /* Set the base address for the file in the VFD now, after adjusting
-         *  space for possible offsets of the HDF5 data in the file.
-         */
-        if(H5FD_set_base_addr(lf, shared->base_addr) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to set base address for file driver")
-    } /* end else */
-
-    /*
-     * The user-defined data is the area of the file before the base
-     * address.
-     */
-    if(H5P_set(c_plist, H5F_CRT_USER_BLOCK_NAME, &shared->base_addr) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set userblock size")
-
-    /*
-     * Make sure that the data is not truncated. One case where this is
-     * possible is if the first file of a family of files was opened
-     * individually.
-     */
-    if(HADDR_UNDEF == (eof = H5FD_get_eof(lf)))
-        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to determine file size")
-    /* (Account for the stored EOA being absolute offset -QAK) */
-    if((eof + H5F_BASE_ADDR(f)) < stored_eoa)
-        HGOTO_ERROR(H5E_FILE, H5E_TRUNCATED, FAIL, "truncated file")
-
-    /*
-     * Tell the file driver how much address space has already been
-     * allocated so that it knows how to allocate additional memory.
-     */
-    /* (Account for the stored EOA being absolute offset -NAF) */
-    if(H5FD_set_eoa(lf, H5FD_MEM_SUPER, stored_eoa - H5F_BASE_ADDR(f)) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to set end-of-address marker for file")
-
-    /* Read the file's superblock extension, if there is one. */
-    if(H5F_addr_defined(shared->extension_addr)) {
-        H5O_loc_t ext_loc;      /* "Object location" for superblock extension */
-        H5O_btreek_t btreek;    /* v1 B-tree 'K' value message from superblock extension */
-        H5O_drvinfo_t drvinfo;  /* Driver info message from superblock extension */
-        htri_t status;          /* Status for message existing */
-
-        /* Sanity check - superblock extension should only be defined for
-         *      superblock version >= 2.
-         */
-        HDassert(super_vers >= HDF5_SUPERBLOCK_VERSION_2);
-
-        /* Check for superblock extension being located "outside" the stored
-         *      'eoa' value, which can occur with the split/multi VFD.
-         */
-        if(H5F_addr_gt(shared->extension_addr, stored_eoa)) {
-            /* Set the 'eoa' for the object header memory type large enough
-             *  to give some room for a reasonably sized superblock extension.
-             *  (This is _rather_ a kludge -QAK)
-             */
-            if(H5FD_set_eoa(lf, H5FD_MEM_OHDR, (haddr_t)(shared->extension_addr + 1024)) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to set end-of-address marker for file")
-        } /* end if */
+    /* Determine file intent for superblock protect */
+    if(H5F_INTENT(f) & H5F_ACC_RDWR)
+        rw = H5AC_WRITE;
+    else
+        rw = H5AC_READ;
 
-        /* Open the superblock extension */
-	if(H5F_super_ext_open(f, &ext_loc) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, FAIL, "unable to start file's superblock extension")
-
-        /* Check for the extension having a 'driver info' message */
-        if((status = H5O_msg_exists(&ext_loc, H5O_DRVINFO_ID, dxpl_id)) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to read object header")
-        if(status) {
-            /* Retrieve the 'driver info' structure */
-            if(NULL == H5O_msg_read(&ext_loc, H5O_DRVINFO_ID, &drvinfo, dxpl_id))
-                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "driver info message not present")
-
-            /* Check if driver matches driver information saved. Unfortunately, we can't push this
-             * function to each specific driver because we're checking if the driver is correct.
-             */
-            if(!HDstrncmp(drvinfo.name, "NCSAfami", (size_t)8) && HDstrcmp(lf->cls->name, "family"))
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "family driver should be used")
-            if(!HDstrncmp(drvinfo.name, "NCSAmult", (size_t)8) && HDstrcmp(lf->cls->name, "multi"))
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "multi driver should be used")
-
-            /* Decode driver information */
-            if(H5FD_sb_decode(lf, drvinfo.name, drvinfo.buf) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to decode driver information")
-
-            /* Reset driver info message */
-            H5O_msg_reset(H5O_DRVINFO_ID, &drvinfo);
-        } /* end if */
+    /* Look up the superblock */
+    if(NULL == (sblock = (H5F_super_t *)H5AC_protect(f, dxpl_id, H5AC_SUPERBLOCK, f->shared->super_addr, NULL, &dirtied, rw)))
+        HGOTO_ERROR(H5E_CACHE, H5E_CANTPROTECT, FAIL, "unable to load superblock")
+    
+    /* Mark the superblock dirty if it was modified during loading or VFD indicated to do so */
+    if((H5AC_WRITE == rw) && (dirtied || H5F_HAS_FEATURE(f, H5FD_FEAT_DIRTY_SBLK_LOAD)))
+        sblock_flags |= H5AC__DIRTIED_FLAG;
 
-        /* Read in the shared OH message information if there is any */
-        if(H5SM_get_info(&ext_loc, c_plist, dxpl_id) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to read SOHM table information")
-
-        /* Check for the extension having a 'v1 B-tree "K"' message */
-        if((status = H5O_msg_exists(&ext_loc, H5O_BTREEK_ID, dxpl_id)) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to read object header")
-        if(status) {
-            /* Retrieve the 'v1 B-tree "K"' structure */
-            if(NULL == H5O_msg_read(&ext_loc, H5O_BTREEK_ID, &btreek, dxpl_id))
-                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "v1 B-tree 'K' info message not present")
-
-            /* Set non-default v1 B-tree 'K' value info from file */
-            shared->btree_k[H5B_CHUNK_ID] = btreek.btree_k[H5B_CHUNK_ID];
-            shared->btree_k[H5B_SNODE_ID] = btreek.btree_k[H5B_SNODE_ID];
-            shared->sym_leaf_k = btreek.sym_leaf_k;
-
-            /* Set non-default v1 B-tree 'K' values in the property list */
-            if(H5P_set(c_plist, H5F_CRT_BTREE_RANK_NAME, btreek.btree_k) < 0)
-                HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set rank for btree internal nodes")
-            if(H5P_set(c_plist, H5F_CRT_SYM_LEAF_NAME, &btreek.sym_leaf_k) < 0)
-                HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set rank for symbol table leaf nodes")
-        } /* end if */
-        else {
-            /* No non-default v1 B-tree 'K' value info in file, use defaults */
-            shared->btree_k[H5B_CHUNK_ID] = HDF5_BTREE_CHUNK_IK_DEF;
-            shared->btree_k[H5B_SNODE_ID] = HDF5_BTREE_SNODE_IK_DEF;
-            shared->sym_leaf_k = H5F_CRT_SYM_LEAF_DEF;
-        } /* end if */
+    /* Pin the superblock in the cache */
+    if(H5AC_pin_protected_entry(f, sblock) < 0)
+        HGOTO_ERROR(H5E_FSPACE, H5E_CANTPIN, FAIL, "unable to pin superblock")
 
-        /* Close superblock extension */
-	if(H5F_super_ext_close(f, &ext_loc) < 0)
-	    HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "unable to close file's superblock extension")
-    } /* end if */
+    /* Set the pointer to the pinned superblock */
+    f->shared->sblock = sblock;
 
 done:
+    /* Release the superblock */
+    if(sblock && H5AC_unprotect(f, dxpl_id, H5AC_SUPERBLOCK, f->shared->super_addr, sblock, sblock_flags) < 0)
+        HDONE_ERROR(H5E_CACHE, H5E_CANTUNPROTECT, FAIL, "unable to close superblock")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_super_read() */
 
@@ -783,21 +352,64 @@ done:
 herr_t
 H5F_super_init(H5F_t *f, hid_t dxpl_id)
 {
-    H5P_genplist_t *plist;              /* File creation property list */
-    hsize_t         userblock_size;     /* Size of userblock, in bytes */
-    hsize_t         superblock_size;    /* Size of superblock, in bytes */
-    size_t          driver_size;        /* Size of driver info block (bytes) */
-    unsigned        super_vers;         /* Superblock version */
-    haddr_t         super_addr;         /* Address of superblock */
+    H5F_super_t    *sblock = NULL;      /* Superblock cache structure                 */
+    hbool_t         sblock_in_cache = FALSE;    /* Whether the superblock has been inserted into the metadata cache */
+    H5P_genplist_t *plist;              /* File creation property list                */
+    hsize_t         userblock_size;     /* Size of userblock, in bytes                */
+    hsize_t         superblock_size;    /* Size of superblock, in bytes               */
+    size_t          driver_size;        /* Size of driver info block (bytes)          */
+    unsigned super_vers = HDF5_SUPERBLOCK_VERSION_DEF; /* Superblock version for file */
+    haddr_t         super_addr;         /* Address of superblock                      */
     hbool_t         need_ext;           /* Whether the superblock extension is needed */
-    herr_t          ret_value = SUCCEED;
+    herr_t          ret_value = SUCCEED; /* Return Value                              */
 
     FUNC_ENTER_NOAPI(H5F_super_init, FAIL)
 
+    /* Allocate space for the superblock */
+    if(NULL == (sblock = H5FL_CALLOC(H5F_super_t)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+    /* Initialize various address information */
+    sblock->base_addr = HADDR_UNDEF;
+    sblock->ext_addr = HADDR_UNDEF;
+    sblock->driver_addr = HADDR_UNDEF;
+    sblock->root_addr = HADDR_UNDEF;
+
     /* Get the shared file creation property list */
     if(NULL == (plist = (H5P_genplist_t *)H5I_object(f->shared->fcpl_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list")
 
+    /* Initialize sym_leaf_k */
+    if(H5P_get(plist, H5F_CRT_SYM_LEAF_NAME, &sblock->sym_leaf_k) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get byte number for object size")
+
+    /* Initialize btree_k */
+    if(H5P_get(plist, H5F_CRT_BTREE_RANK_NAME, &sblock->btree_k[0]) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get rank for btree internal nodes")
+
+    /* Bump superblock version if we are to use the latest version of the format */
+    if(f->shared->latest_format)
+        super_vers = HDF5_SUPERBLOCK_VERSION_LATEST;
+    /* Bump superblock version to create superblock extension for SOHM info */
+    else if(f->shared->sohm_nindexes > 0)
+        super_vers = HDF5_SUPERBLOCK_VERSION_2;
+    /* Check for non-default indexed storage B-tree internal 'K' value
+     * and set the version # of the superblock to 1 if it is a non-default
+     * value.
+     */
+    else if(sblock->btree_k[H5B_CHUNK_ID] != HDF5_BTREE_CHUNK_IK_DEF)
+        super_vers = HDF5_SUPERBLOCK_VERSION_1;
+
+    /* If a newer superblock version is required, set it here */
+    if(super_vers != HDF5_SUPERBLOCK_VERSION_DEF) {
+        H5P_genplist_t *c_plist;              /* Property list */
+
+        if(NULL == (c_plist = (H5P_genplist_t *)H5I_object(f->shared->fcpl_id)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not property list")
+        if(H5P_set(c_plist, H5F_CRT_SUPER_VERS_NAME, &super_vers) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set superblock version")
+    } /* end if */
+
     /*
      * The superblock starts immediately after the user-defined
      * header, which we have already insured is a proper size. The
@@ -806,8 +418,9 @@ H5F_super_init(H5F_t *f, hid_t dxpl_id)
      */
     if(H5P_get(plist, H5F_CRT_USER_BLOCK_NAME, &userblock_size) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get userblock size")
-    f->shared->base_addr = userblock_size;
-    f->shared->status_flags = 0;
+
+    sblock->base_addr = userblock_size;
+    sblock->status_flags = 0;
 
     /* Reserve space for the userblock */
     if(H5FD_set_eoa(f->shared->lf, H5FD_MEM_SUPER, userblock_size) < 0)
@@ -816,12 +429,11 @@ H5F_super_init(H5F_t *f, hid_t dxpl_id)
     /* Set the base address for the file in the VFD now, after allocating
      *  space for userblock.
      */
-    if(H5FD_set_base_addr(f->shared->lf, f->shared->base_addr) < 0)
+    if(H5FD_set_base_addr(f->shared->lf, sblock->base_addr) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to set base address for file driver")
 
-    /* Grab superblock version from property list */
-    if(H5P_get(plist, H5F_CRT_SUPER_VERS_NAME, &super_vers) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get superblock version")
+    /* Save a local copy of the superblock version number */
+    sblock->super_vers = super_vers;
 
     /* Compute the size of the superblock */
     superblock_size = H5F_SUPERBLOCK_SIZE(super_vers, f);
@@ -835,7 +447,7 @@ H5F_super_init(H5F_t *f, hid_t dxpl_id)
          * The file driver information block begins immediately after the
          * superblock. (relative to base address in file)
          */
-        f->shared->driver_addr = superblock_size;
+        sblock->driver_addr = superblock_size;
     } /* end if */
 
     /*
@@ -846,11 +458,22 @@ H5F_super_init(H5F_t *f, hid_t dxpl_id)
      */
     if(super_vers < HDF5_SUPERBLOCK_VERSION_2)
         superblock_size += driver_size;
-    super_addr = H5MF_alloc(f, H5FD_MEM_SUPER, dxpl_id, superblock_size);
-    if(HADDR_UNDEF == super_addr)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to allocate file space for userblock and/or superblock")
-    if(0 != super_addr)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "file driver failed to allocate userblock and/or superblock at address zero")
+
+    /* Reserve space in the file for the superblock, instead of allocating it */
+    if(H5FD_set_eoa(f->shared->lf, H5FD_MEM_SUPER, superblock_size) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to set EOA value for superblock")
+
+    /* Set the superblock's address, it must be immediately after any userblock */
+    super_addr = (haddr_t)0;
+
+    /* Insert superblock into cache, pinned */
+    if(H5AC_set(f, dxpl_id, H5AC_SUPERBLOCK, super_addr, sblock, H5AC__PIN_ENTRY_FLAG) < 0)
+        HGOTO_ERROR(H5E_CACHE, H5E_CANTINS, FAIL, "can't add superblock to cache")
+    sblock_in_cache = TRUE;
+
+    /* Keep a copy of the superblock info */
+    f->shared->sblock = sblock;
+    f->shared->super_addr = super_addr;
 
     /*
      * Determine if we will need a superblock extension
@@ -867,9 +490,9 @@ H5F_super_init(H5F_t *f, hid_t dxpl_id)
      */
     else if(super_vers >= HDF5_SUPERBLOCK_VERSION_2) {
         /* Check for non-default v1 B-tree 'K' values to store */
-        if(f->shared->btree_k[H5B_SNODE_ID] != HDF5_BTREE_SNODE_IK_DEF ||
-                f->shared->btree_k[H5B_CHUNK_ID] != HDF5_BTREE_CHUNK_IK_DEF ||
-                f->shared->sym_leaf_k != H5F_CRT_SYM_LEAF_DEF)
+        if(sblock->btree_k[H5B_SNODE_ID] != HDF5_BTREE_SNODE_IK_DEF ||
+                sblock->btree_k[H5B_CHUNK_ID] != HDF5_BTREE_CHUNK_IK_DEF ||
+                sblock->sym_leaf_k != H5F_CRT_SYM_LEAF_DEF)
             need_ext = TRUE;
         /* Check for driver info to store */
         else if(driver_size > 0)
@@ -905,15 +528,15 @@ H5F_super_init(H5F_t *f, hid_t dxpl_id)
         } /* end if */
 
         /* Check for non-default v1 B-tree 'K' values to store */
-        if(f->shared->btree_k[H5B_SNODE_ID] != HDF5_BTREE_SNODE_IK_DEF ||
-                f->shared->btree_k[H5B_CHUNK_ID] != HDF5_BTREE_CHUNK_IK_DEF ||
-                f->shared->sym_leaf_k != H5F_CRT_SYM_LEAF_DEF) {
+        if(sblock->btree_k[H5B_SNODE_ID] != HDF5_BTREE_SNODE_IK_DEF ||
+                sblock->btree_k[H5B_CHUNK_ID] != HDF5_BTREE_CHUNK_IK_DEF ||
+                sblock->sym_leaf_k != H5F_CRT_SYM_LEAF_DEF) {
             H5O_btreek_t btreek;        /* v1 B-tree 'K' value message for superblock extension */
 
             /* Write v1 B-tree 'K' value information to the superblock extension */
-            btreek.btree_k[H5B_CHUNK_ID] = f->shared->btree_k[H5B_CHUNK_ID];
-            btreek.btree_k[H5B_SNODE_ID] = f->shared->btree_k[H5B_SNODE_ID];
-            btreek.sym_leaf_k = f->shared->sym_leaf_k;
+            btreek.btree_k[H5B_CHUNK_ID] = sblock->btree_k[H5B_CHUNK_ID];
+            btreek.btree_k[H5B_SNODE_ID] = sblock->btree_k[H5B_SNODE_ID];
+            btreek.sym_leaf_k = sblock->sym_leaf_k;
             if(H5O_msg_create(&ext_loc, H5O_BTREEK_ID, H5O_MSG_FLAG_CONSTANT | H5O_MSG_FLAG_DONTSHARE, H5O_UPDATE_TIME, &btreek, dxpl_id) < 0)
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to update v1 B-tree 'K' value header message")
         } /* end if */
@@ -943,194 +566,66 @@ H5F_super_init(H5F_t *f, hid_t dxpl_id)
     } /* end if */
 
 done:
+    /* Cleanup on failure */
+    if(ret_value < 0) {
+        /* Check if the superblock has been allocated yet */
+        if(sblock) {
+            /* Check if we've cached it already */
+            if(sblock_in_cache) {
+                /* Unpin superblock in cache */
+                if(H5AC_unpin_entry(f, sblock) < 0)
+                    HDONE_ERROR(H5E_FILE, H5E_CANTUNPIN, FAIL, "unable to unpin superblock")
+
+                /* Evict the superblock from the cache */
+                if(H5AC_expunge_entry(f, dxpl_id, H5AC_SUPERBLOCK, super_addr, H5AC__NO_FLAGS_SET) < 0)
+                    HDONE_ERROR(H5E_FILE, H5E_CANTEXPUNGE, FAIL, "unable to expunge superblock")
+            } /* end if */
+            else
+                /* Free superblock */
+                sblock = (H5F_super_t *)H5FL_FREE(H5F_super_t, sblock);
+
+            /* Reset variables in file structure */
+            f->shared->sblock = NULL;
+            f->shared->super_addr = HADDR_UNDEF;
+        } /* end if */
+    } /* end if */
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_super_init() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5F_super_write
+ * Function:    H5F_super_dirty
  *
- * Purpose:     Writes the superblock for the file.
+ * Purpose:     Mark the file's superblock dirty
  *
- * Return:      Success:        SUCCEED
- *              Failure:        FAIL
+ * Return:      Success:        non-negative on success
+ *              Failure:        Negative
  *
- * Programmer:  Bill Wendling
- *              wendling@ncsa.uiuc.edu
- *              Sept 12, 2003
+ * Programmer:  Quincey Koziol
+ *              August 14, 2009
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5F_super_write(H5F_t *f, hid_t dxpl_id)
+H5F_super_dirty(H5F_t *f)
 {
-    H5P_genplist_t *plist;                      /* File creation property list */
-    uint8_t         buf[H5F_MAX_SUPERBLOCK_SIZE + H5F_MAX_DRVINFOBLOCK_SIZE];  /* Superblock & driver info blockencoding buffer */
-    uint8_t        *p;                          /* Ptr into encoding buffer */
-    haddr_t         rel_eoa;                    /* Relative EOA for file */
-    size_t          superblock_size;            /* Size of superblock, in bytes */
-    size_t          driver_size;                /* Size of driver info block (bytes)*/
-    unsigned        super_vers;                 /* Superblock version              */
-    herr_t          ret_value = SUCCEED;
-
-    FUNC_ENTER_NOAPI(H5F_super_write, FAIL)
-
-    /* Get the shared file creation property list */
-    if(NULL == (plist = (H5P_genplist_t *)H5I_object(f->shared->fcpl_id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list")
-
-    /* Grab values from property list */
-    if(H5P_get(plist, H5F_CRT_SUPER_VERS_NAME, &super_vers) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get superblock version")
-
-    /* Encode the common portion of the file superblock for all versions */
-    p = buf;
-    HDmemcpy(p, H5F_SIGNATURE, (size_t)H5F_SIGNATURE_LEN);
-    p += H5F_SIGNATURE_LEN;
-    *p++ = (uint8_t)super_vers;
-
-    /* Check for older version of superblock format */
-    if(super_vers < HDF5_SUPERBLOCK_VERSION_2) {
-        *p++ = (uint8_t)HDF5_FREESPACE_VERSION;     /* (hard-wired) */
-        *p++ = (uint8_t)HDF5_OBJECTDIR_VERSION;     /* (hard-wired) */
-        *p++ = 0;   /* reserved*/
-
-        *p++ = (uint8_t)HDF5_SHAREDHEADER_VERSION;  /* (hard-wired) */
-        HDassert(H5F_SIZEOF_ADDR(f) <= 255);
-        *p++ = (uint8_t)H5F_SIZEOF_ADDR(f);
-        HDassert(H5F_SIZEOF_SIZE(f) <= 255);
-        *p++ = (uint8_t)H5F_SIZEOF_SIZE(f);
-        *p++ = 0;   /* reserved */
-
-        UINT16ENCODE(p, f->shared->sym_leaf_k);
-        UINT16ENCODE(p, f->shared->btree_k[H5B_SNODE_ID]);
-        UINT32ENCODE(p, (uint32_t)f->shared->status_flags);
-
-        /*
-         * Versions of the superblock >0 have the indexed storage B-tree
-         * internal 'K' value stored
-         */
-        if(super_vers > HDF5_SUPERBLOCK_VERSION_DEF) {
-            UINT16ENCODE(p, f->shared->btree_k[H5B_CHUNK_ID]);
-            *p++ = 0;   /*reserved */
-            *p++ = 0;   /*reserved */
-        } /* end if */
-
-        H5F_addr_encode(f, &p, f->shared->base_addr);
-        H5F_addr_encode(f, &p, f->shared->extension_addr);
-        rel_eoa = H5FD_get_eoa(f->shared->lf, H5FD_MEM_SUPER);
-        H5F_addr_encode(f, &p, (rel_eoa + f->shared->base_addr));
-        H5F_addr_encode(f, &p, f->shared->driver_addr);
-
-        /* Encode the root group object entry, including the cached stab info */
-        if(H5G_root_ent_encode(f, &p) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode root group information")
-
-        /* Encode the driver information block. */
-        H5_ASSIGN_OVERFLOW(driver_size, H5FD_sb_size(f->shared->lf), hsize_t, size_t);
-
-        /* Checking whether driver block address is defined here is to handle backward
-         * compatibility.  If the file was created with v1.6 library or earlier and no
-         * driver info block was written in the superblock, we don't write it either even
-         * though there's some driver info.  Otherwise, the driver block extended will
-         * overwrite the (meta)data right after the superblock. This situation happens to
-         * the family driver particularly.  SLU - 2009/3/24 
-         */
-        if(driver_size > 0 && H5F_addr_defined(f->shared->driver_addr)) {
-            char driver_name[9];    /* Name of driver, for driver info block */
-            uint8_t *dbuf = p;      /* Pointer to beginning of driver info */
-
-            /* Encode the driver information block */
-            *p++ = HDF5_DRIVERINFO_VERSION_0; /* Version */
-            *p++ = 0; /* reserved */
-            *p++ = 0; /* reserved */
-            *p++ = 0; /* reserved */
-
-            /* Driver info size, excluding header */
-            UINT32ENCODE(p, driver_size);
-
-            /* Encode driver-specific data */
-            if(H5FD_sb_encode(f->shared->lf, driver_name, dbuf + H5F_DRVINFOBLOCK_HDR_SIZE) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information")
-
-            /* Store driver name (set in 'H5FD_sb_encode' call above) */
-            HDmemcpy(p, driver_name, (size_t)8);
-
-            /* Advance buffer pointer past name & variable-sized portion of driver info */
-            /* (for later use in computing the superblock size) */
-            p += 8 + driver_size;
-        } /* end if */
-    } /* end if */
-    else {
-        uint32_t        chksum;                 /* Checksum temporary variable      */
-        H5O_loc_t       *root_oloc;             /* Pointer to root group's object location */
-
-        /* Size of file addresses & offsets, and status flags */
-        HDassert(H5F_SIZEOF_ADDR(f) <= 255);
-        *p++ = (uint8_t)H5F_SIZEOF_ADDR(f);
-        HDassert(H5F_SIZEOF_SIZE(f) <= 255);
-        *p++ = (uint8_t)H5F_SIZEOF_SIZE(f);
-        *p++ = f->shared->status_flags;
-
-        /* Base, superblock extension & end of file addresses */
-        H5F_addr_encode(f, &p, f->shared->base_addr);
-        H5F_addr_encode(f, &p, f->shared->extension_addr);
-        rel_eoa = H5FD_get_eoa(f->shared->lf, H5FD_MEM_SUPER);
-        H5F_addr_encode(f, &p, (rel_eoa + f->shared->base_addr));
-
-        /* Retrieve information for root group */
-        if(NULL == (root_oloc = H5G_oloc(f->shared->root_grp)))
-            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to retrieve root group information")
-
-        /* Encode address of root group's object header */
-        H5F_addr_encode(f, &p, root_oloc->addr);
-
-        /* Compute superblock checksum */
-        chksum = H5_checksum_metadata(buf, (H5F_SUPERBLOCK_SIZE(super_vers, f) - H5F_SIZEOF_CHKSUM), 0);
-
-        /* Superblock checksum */
-        UINT32ENCODE(p, chksum);
-
-        /* Sanity check */
-        HDassert((size_t)(p - buf) == H5F_SUPERBLOCK_SIZE(super_vers, f));
-    } /* end else */
-
-    /* Retrieve the total size of the superblock info */
-    H5_ASSIGN_OVERFLOW(superblock_size, (p - buf), int, size_t);
-
-    /* Double check we didn't overrun the block (unlikely) */
-    HDassert(superblock_size <= sizeof(buf));
-
-    /* Write superblock (always at relative offset 0) */
-    if(H5FD_write(f->shared->lf, dxpl_id, H5FD_MEM_SUPER, (haddr_t)0, superblock_size, buf) < 0)
-        HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write superblock")
-
-    /* Check for newer version of superblock format & superblock extension */
-    if(super_vers >= HDF5_SUPERBLOCK_VERSION_2 && H5F_addr_defined(f->shared->extension_addr)) {
-        /* Check for driver info message */
-        H5_ASSIGN_OVERFLOW(driver_size, H5FD_sb_size(f->shared->lf), hsize_t, size_t);
-        if(driver_size > 0) {
-            H5O_drvinfo_t drvinfo;      /* Driver info */
-            uint8_t dbuf[H5F_MAX_DRVINFOBLOCK_SIZE];  /* Driver info block encoding buffer */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-            /* Sanity check */
-            HDassert(driver_size <= H5F_MAX_DRVINFOBLOCK_SIZE);
+    FUNC_ENTER_NOAPI(H5F_super_dirty, FAIL)
 
-            /* Encode driver-specific data */
-            if(H5FD_sb_encode(f->shared->lf, drvinfo.name, dbuf) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information")
+    /* Sanity check */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->sblock);
 
-            /* Write driver info information to the superblock extension */
-            drvinfo.len = driver_size;
-            drvinfo.buf = dbuf;
-	    if(H5F_super_ext_write_msg(f, dxpl_id, &drvinfo, H5O_DRVINFO_ID, FALSE) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_WRITEERROR, FAIL, "unable to update driver info header message")
-        } /* end if */
-    } /* end if */
+    /* Mark superblock dirty in cache, so change to EOA will get encoded */
+    if(H5AC_mark_pinned_or_protected_entry_dirty(f, f->shared->sblock) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTMARKDIRTY, FAIL, "unable to mark superblock as dirty")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F_super_write() */
+} /* H5F_super_dirty() */
 
 
 /*-------------------------------------------------------------------------
@@ -1143,6 +638,7 @@ done:
  *
  * Programmer:  Vailin Choi
  *              July 11, 2007
+ *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -1154,34 +650,23 @@ H5F_super_size(H5F_t *f, hid_t dxpl_id, hsize_t *super_size, hsize_t *super_ext_
 
     /* Sanity check */
     HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->sblock);
 
     /* Set the superblock size */
-    if(super_size) {
-        H5P_genplist_t *plist;           	/* File creation property list */
-        unsigned        super_vers;       	/* Superblock version          */
-
-        /* Get the shared file creation property list */
-        if(NULL == (plist = (H5P_genplist_t *)H5I_object(f->shared->fcpl_id)))
-            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list")
-
-        /* Grab values from property list */
-        if(H5P_get(plist, H5F_CRT_SUPER_VERS_NAME, &super_vers) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get superblock version")
-
-        /* Set the superblock size */
-	*super_size = H5F_SUPERBLOCK_SIZE(super_vers, f);
-    } /* end if */
+    if(super_size)
+	*super_size = H5F_SUPERBLOCK_SIZE(f->shared->sblock->super_vers, f);
 
     /* Set the superblock extension size */
     if(super_ext_size) {
-        if(H5F_addr_defined(f->shared->extension_addr)) {
+        if(H5F_addr_defined(f->shared->sblock->ext_addr)) {
             H5O_loc_t ext_loc;                  /* "Object location" for superblock extension */
             H5O_info_t oinfo;                   /* Object info for superblock extension */
 
             /* Set up "fake" object location for superblock extension */
             H5O_loc_reset(&ext_loc);
             ext_loc.file = f;
-            ext_loc.addr = f->shared->extension_addr;
+            ext_loc.addr = f->shared->sblock->ext_addr;
 
             /* Get object header info for superblock extension */
             if(H5O_get_info(&ext_loc, dxpl_id, FALSE, &oinfo) < 0)
@@ -1211,24 +696,31 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
+herr_t
 H5F_super_ext_write_msg(H5F_t *f, hid_t dxpl_id, void *mesg, unsigned id, hbool_t may_create)
 {
+    hbool_t     sblock_dirty = FALSE;   /* Whether superblock was dirtied */
     H5O_loc_t 	ext_loc; 	/* "Object location" for superblock extension */
     htri_t 	status;       	/* Indicate whether the message exists or not */
     herr_t 	ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5F_super_ext_write_msg)
 
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->sblock);
+
     /* Open/create the superblock extension object header */
-    if(H5F_addr_defined(f->shared->extension_addr)) {
-	if(H5F_super_ext_open(f, &ext_loc) < 0)
+    if(H5F_addr_defined(f->shared->sblock->ext_addr)) {
+	if(H5F_super_ext_open(f, f->shared->sblock->ext_addr, &ext_loc) < 0)
 	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, FAIL, "unable to open file's superblock extension")
     } /* end if */
     else {
         HDassert(may_create);
 	if(H5F_super_ext_create(f, dxpl_id, &ext_loc) < 0)
 	    HGOTO_ERROR(H5E_FILE, H5E_CANTCREATE, FAIL, "unable to create file's superblock extension")
+        sblock_dirty = TRUE;
     } /* end else */
     HDassert(H5F_addr_defined(ext_loc.addr));
 
@@ -1259,6 +751,11 @@ H5F_super_ext_write_msg(H5F_t *f, hid_t dxpl_id, void *mesg, unsigned id, hbool_
 	HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "unable to close file's superblock extension")
 
 done:
+    /* Mark superblock dirty in cache, if necessary */
+    if(sblock_dirty)
+        if(H5AC_mark_pinned_or_protected_entry_dirty(f, f->shared->sblock) < 0)
+            HDONE_ERROR(H5E_FILE, H5E_CANTMARKDIRTY, FAIL, "unable to mark superblock as dirty")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5F_super_ext_write_msg() */