[svn-r11022] Purpose:

    Bug fix & code cleanup

Description:
    Don't unmount child files from a parent file if the parent file is
being held open by an object.

    Also, moved the mounting routines into their own source file and the
superblock routines into their own file also.

Solution:
    Moved the code for unmounting child files down in the H5F_close routine
and also add checks to the file and group mounting code to unmount child
files when the last object holding open a file closes.

Platforms tested:
    FreeBSD 4.11 (sleipnir)
    h5committest

1 files changed, 646 insertions, 0 deletions

diff --git a/src/H5Fsuper.c b/src/H5Fsuper.c
new file mode 100644
index 0000000..4cb1646
--- /dev/null
+++ b/src/H5Fsuper.c
@@ -0,0 +1,646 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+#define H5F_PACKAGE		/*suppress error about including H5Fpkg	  */
+
+/* Interface initialization */
+#define H5_INTERFACE_INIT_FUNC	H5F_init_super_interface
+
+
+/* Packages needed by this file... */
+#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 "H5Pprivate.h"		/* Property lists			*/
+
+/* PRIVATE PROTOTYPES */
+
+
+/*--------------------------------------------------------------------------
+NAME
+   H5F_init_super_interface -- Initialize interface-specific information
+USAGE
+    herr_t H5T_init_super_interface()
+   
+RETURNS
+    Non-negative on success/Negative on failure
+DESCRIPTION
+    Initializes any interface-specific data or routines.  (Just calls
+    H5F_init_iterface currently).
+
+--------------------------------------------------------------------------*/
+static herr_t
+H5F_init_super_interface(void)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5F_init_super_interface)
+
+    FUNC_LEAVE_NOAPI(H5F_init())
+} /* H5F_init_super_interface() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5F_read_superblock
+ *
+ * Purpose:     Reads the superblock from the file or from the BUF. If
+ *              ADDR is a valid address, then it reads it from the file.
+ *              If not, then BUF must be non-NULL for it to read from the
+ *              BUF.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  Bill Wendling
+ *              wendling@ncsa.uiuc.edu
+ *              Sept 12, 2003
+ *
+ * Modifications:
+ *              Raymond Lu
+ *              May 24, 2005
+ *              Started to check if driver(only family and multi drivers) 
+ *              matches driver information saved in the superblock.  Wrong
+ *              driver will result in a failure.
+ * 
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_read_superblock(H5F_t *f, hid_t dxpl_id, H5G_entry_t *root_ent, haddr_t addr, uint8_t *buf, size_t buf_size)
+{
+    haddr_t             stored_eoa;         /*relative end-of-addr in file  */
+    haddr_t             eof;                /*end of file address           */
+    uint8_t            *q;                  /*ptr into temp I/O buffer      */
+    size_t              sizeof_addr = 0;
+    size_t              sizeof_size = 0;
+    const size_t        fixed_size = 24;    /*fixed sizeof superblock       */
+    unsigned            sym_leaf_k = 0;
+    size_t              variable_size;      /*variable sizeof superblock    */
+    unsigned            btree_k[H5B_NUM_BTREE_ID];  /* B-tree internal node 'K' values */
+    H5F_file_t         *shared = NULL;      /* shared part of `file'        */
+    H5FD_t             *lf = NULL;          /* file driver part of `shared' */
+    uint8_t            *p;                  /* Temporary pointer into encoding buffers */
+    uint8_t            *start_p;            /* Start of encoding buffers    */
+    unsigned            i;                  /* Index variable               */
+    unsigned            chksum;             /* Checksum temporary variable  */
+    size_t              driver_size;        /* Size of driver info block, in bytes */
+    char                driver_name[9];     /* Name of driver, for driver info block */
+    unsigned            super_vers;         /* Super block version          */
+    unsigned            freespace_vers;     /* Freespace info version       */
+    unsigned            obj_dir_vers;       /* Object header info version   */
+    unsigned            share_head_vers;    /* Shared header info version   */
+    uint8_t             sbuf[H5F_SUPERBLOCK_SIZE];     /* Local buffer                 */
+    H5P_genplist_t     *c_plist;            /* File creation property list  */
+    herr_t              ret_value = SUCCEED;
+
+    /* Decoding */
+    FUNC_ENTER_NOAPI(H5F_read_superblock, FAIL)
+
+    /* Short cuts */
+    shared = f->shared;
+    lf = shared->lf;
+
+    /* Get the shared file creation property list */
+    if (NULL == (c_plist = H5I_object(shared->fcpl_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "can't get property list")
+
+    /* Read the superblock if it hasn't been read before. */
+    if (addr == HADDR_UNDEF) {
+        if (HADDR_UNDEF == (shared->super_addr=H5F_locate_signature(lf,dxpl_id)))
+            HGOTO_ERROR(H5E_FILE, H5E_NOTHDF5, FAIL, "unable to find file signature")
+    } else {
+        shared->super_addr = addr;
+    }
+
+    if (!buf) {
+        start_p = p = sbuf;
+        buf_size=sizeof(sbuf);
+
+        if (H5FD_set_eoa(lf, shared->super_addr + fixed_size) < 0 ||
+                H5FD_read(lf, H5FD_MEM_SUPER, dxpl_id, shared->super_addr, fixed_size, p) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_READERROR, FAIL, "unable to read superblock")
+    } else {
+        start_p = p = buf;
+    }
+
+    /* Signature, already checked */
+    p += H5F_SIGNATURE_LEN;
+
+    /* Superblock version */
+    super_vers = *p++;
+    if (super_vers > HDF5_SUPERBLOCK_VERSION_MAX) 
+        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")
+
+    /* Freespace version */
+    freespace_vers = *p++;
+    if (HDF5_FREESPACE_VERSION != freespace_vers) 
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad free space version number")
+    if (H5P_set(c_plist, H5F_CRT_FREESPACE_VERS_NAME, &freespace_vers) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to free space version")
+
+    /* Root group version number */
+    obj_dir_vers = *p++;
+    if (HDF5_OBJECTDIR_VERSION != obj_dir_vers) 
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad object directory version number")
+    if (H5P_set(c_plist, H5F_CRT_OBJ_DIR_VERS_NAME, &obj_dir_vers) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set object directory version")
+
+    /* Skip over reserved byte */
+    p++;
+
+    /* Shared header version number */
+    share_head_vers = *p++;
+    if (HDF5_SHAREDHEADER_VERSION != share_head_vers) 
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad shared-header format version number")
+    if (H5P_set(c_plist, H5F_CRT_SHARE_HEAD_VERS_NAME, &share_head_vers) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set shared-header format version")
+
+    /* 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 consistency flags. Not really used yet */
+    UINT32DECODE(p, shared->consist_flags);
+    assert(((size_t)(p - start_p)) == fixed_size);
+
+    /* Decode the variable-length part of the superblock... */
+    variable_size = (super_vers>0 ? 4 : 0) +    /* Potential indexed storage B-tree internal 'K' value */
+                    H5F_SIZEOF_ADDR(f) +        /*base addr*/
+                    H5F_SIZEOF_ADDR(f) +        /*global free list*/
+                    H5F_SIZEOF_ADDR(f) +        /*end-of-address*/
+                    H5F_SIZEOF_ADDR(f) +        /*reserved address*/
+                    H5G_SIZEOF_ENTRY(f);        /*root group ptr*/
+    assert(fixed_size + variable_size <= buf_size);
+
+    /* The buffer (buf) is either passed in or the "local_buf" variable now */
+    if(!buf) {
+        if (H5FD_set_eoa(lf, shared->super_addr + fixed_size+variable_size) < 0 ||
+                H5FD_read(lf, H5FD_MEM_SUPER, dxpl_id, shared->super_addr + fixed_size,
+                          variable_size, p) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to read superblock")
+    } /* end if */
+
+    /*
+     * If the superblock version # is greater than 0, read in the indexed
+     * storage B-tree internal 'K' value
+     */
+    if (super_vers > 0) {
+        UINT16DECODE(p, btree_k[H5B_ISTORE_ID]);
+        p += 2;   /* reserved */
+    }
+    else
+        btree_k[H5B_ISTORE_ID] = HDF5_BTREE_ISTORE_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 */
+
+    H5F_addr_decode(f, (const uint8_t **)&p, &shared->base_addr/*out*/);
+    H5F_addr_decode(f, (const uint8_t **)&p, &shared->freespace_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*/);
+    if (H5G_ent_decode(f, (const uint8_t **)&p, root_ent/*out*/) < 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(shared->super_addr,shared->base_addr)) {
+        /* Check if the superblock moved earlier in the file */
+        if (H5F_addr_lt(shared->super_addr, shared->base_addr))
+            stored_eoa -= (shared->base_addr - shared->super_addr);
+        else
+            /* The superblock moved later in the file */
+            stored_eoa += (shared->super_addr - shared->base_addr);
+
+        shared->base_addr = shared->super_addr;
+    } /* end if */
+
+    /* Compute super block checksum */
+    assert(sizeof(chksum) == sizeof(shared->super_chksum));
+    for (q = (uint8_t *)&chksum, chksum = 0, i = 0; i < fixed_size + variable_size; ++i)
+        q[i % sizeof(shared->super_chksum)] ^= start_p[i];
+
+    /* Set the super block checksum */
+    shared->super_chksum = chksum;
+
+    /* 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)) {
+        haddr_t drv_addr = shared->base_addr + shared->driver_addr;
+        uint8_t dbuf[H5F_DRVINFOBLOCK_SIZE];     /* Local buffer                 */
+        size_t dbuf_size;               /* Size available for driver info */
+        const uint8_t *driver_p;        /* Remember beginning of driver info block */
+
+        if(!buf) {
+            driver_p = p = dbuf;
+            dbuf_size=sizeof(dbuf);
+
+            if (H5FD_set_eoa(lf, drv_addr + 16) < 0 ||
+                    H5FD_read(lf, H5FD_MEM_SUPER, dxpl_id, drv_addr, (size_t)16, p) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to read driver information block")
+        } /* end if */
+        else {
+            driver_p = p;
+            dbuf_size=buf_size-(p-start_p);
+        } /* end else */
+
+        /* Version number */
+        if (HDF5_DRIVERINFO_VERSION != *p++)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "bad driver information block version number")
+
+        p += 3; /* reserved */
+
+        /* Driver info size */
+        UINT32DECODE(p, driver_size);
+
+        /* Driver name and/or version */
+        HDstrncpy(driver_name, (const char *)p, (size_t)8);
+        driver_name[8] = '\0';
+        p += 8; /* advance past name/version */
+
+        /* Read driver information and decode */
+        assert((driver_size + 16) <= dbuf_size);
+
+        if(!buf) {
+            if (H5FD_set_eoa(lf, drv_addr + 16 + driver_size) < 0 ||
+                    H5FD_read(lf, H5FD_MEM_SUPER, dxpl_id, drv_addr+16, driver_size, p) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to read file driver information")
+        } /* end if */
+
+        /* 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(driver_name, "NCSAfami", 8) && HDstrcmp(lf->cls->name, "family"))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "family driver should be used")
+        if(!HDstrncmp(driver_name, "NCSAmult", 8) && HDstrcmp(lf->cls->name, "multi"))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "multi driver should be used")
+           
+        if (H5FD_sb_decode(lf, driver_name, p) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to decode driver information")
+
+        /* Compute driver info block checksum */
+        assert(sizeof(chksum) == sizeof(shared->drvr_chksum));
+        for (q = (uint8_t *)&chksum, chksum = 0, i = 0; i < (driver_size + 16); ++i)
+            q[i % sizeof(shared->drvr_chksum)] ^= driver_p[i];
+
+        /* Set the driver info block checksum */
+        shared->drvr_chksum = chksum;
+    } /* end if */
+    
+    /*
+     * 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 usr block 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")
+
+#ifdef H5_HAVE_FPHDF5
+    if (!H5FD_is_fphdf5_driver(lf) || H5FD_fphdf5_is_captain(lf))
+#endif  /* !H5_HAVE_FPHDF5 */
+        if (eof < 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.
+     */
+    if (H5FD_set_eoa(lf, stored_eoa) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to set end-of-address marker for file")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5F_init_superblock
+ *
+ * Purpose:     Allocates the superblock for the file and initializes
+ *              information about the superblock in memory.  Does not write
+ *              any superblock information to the file.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  Quincey Koziol
+ *              koziol@ncsa.uiuc.edu
+ *              Sept 15, 2003
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+hsize_t
+H5F_init_superblock(const H5F_t *f, hid_t dxpl_id)
+{
+    hsize_t         userblock_size = 0;         /* Size of userblock, in bytes */
+    size_t          superblock_size;            /* Size of superblock, in bytes     */
+    size_t          driver_size;                /* Size of driver info block (bytes)*/
+    unsigned        super_vers;                 /* Super block version              */
+    haddr_t         addr;                       /* Address of superblock            */
+    H5P_genplist_t *plist;                      /* Property list                    */
+    hsize_t         ret_value;
+
+    /* Encoding */
+    FUNC_ENTER_NOAPI(H5F_init_superblock, UFAIL)
+
+    /* Get the shared file creation property list */
+    if (NULL == (plist = H5I_object(f->shared->fcpl_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, UFAIL, "not a property list")
+
+    /*
+     * The superblock starts immediately after the user-defined
+     * header, which we have already insured is a proper size. The
+     * base address is set to the same thing as the superblock for
+     * now.
+     */
+    if(H5P_get(plist, H5F_CRT_USER_BLOCK_NAME, &userblock_size) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, UFAIL, "unable to get user block size")
+    f->shared->super_addr = userblock_size;
+    f->shared->base_addr = f->shared->super_addr;
+    f->shared->consist_flags = 0x03;
+
+    /* Grab superblock version from property list */
+    if (H5P_get(plist, H5F_CRT_SUPER_VERS_NAME, &super_vers) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, UFAIL, "unable to get super block version")
+
+    /* Compute the size of the superblock */
+    superblock_size=H5F_SIGNATURE_LEN   /* Signature length (8 bytes) */
+        + 16                            /* Length of required fixed-size portion */
+        + ((super_vers>0) ? 4 : 0)      /* Version specific fixed-size portion */
+        + 4 * H5F_sizeof_addr(f)        /* Variable-sized addresses */
+        + H5G_SIZEOF_ENTRY(f);          /* Size of root group symbol table entry */
+
+    /* Compute the size of the driver information block. */
+    H5_ASSIGN_OVERFLOW(driver_size, H5FD_sb_size(f->shared->lf), hsize_t, size_t);
+    if (driver_size > 0)
+	driver_size += 16; /* Driver block header */
+
+    /*
+     * Allocate space for the userblock, superblock, and driver info
+     * block. We do it with one allocation request because the
+     * userblock and superblock need to be at the beginning of the
+     * file and only the first allocation request is required to
+     * return memory at format address zero.
+     */
+
+    H5_CHECK_OVERFLOW(f->shared->base_addr, haddr_t, hsize_t);
+    addr = H5FD_alloc(f->shared->lf, H5FD_MEM_SUPER, dxpl_id,
+                      ((hsize_t)f->shared->base_addr + superblock_size + driver_size));
+
+    if (HADDR_UNDEF == addr)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, UFAIL,
+                    "unable to allocate file space for userblock and/or superblock")
+
+    if (0 != addr)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, UFAIL,
+                    "file driver failed to allocate userblock and/or superblock at address zero")
+
+    /*
+     * The file driver information block begins immediately after the
+     * superblock.
+     */
+    if (driver_size > 0)
+        f->shared->driver_addr = superblock_size;
+
+    /* Return the size of the super block+driver info block */
+    ret_value=superblock_size+driver_size;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_init_superblock() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5F_write_superblock
+ *
+ * Purpose:     Writes (and optionally allocates) the superblock for the file.
+ *              If BUF is non-NULL, then write the serialized superblock
+ *              information into it. It should be a buffer of size
+ *              H5F_SUPERBLOCK_SIZE + H5F_DRVINFOBLOCK_SIZE or larger.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  Bill Wendling
+ *              wendling@ncsa.uiuc.edu
+ *              Sept 12, 2003
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_write_superblock(H5F_t *f, hid_t dxpl_id, uint8_t *buf)
+{
+    uint8_t         sbuf[H5F_SUPERBLOCK_SIZE];  /* Superblock encoding buffer       */
+    uint8_t         dbuf[H5F_DRVINFOBLOCK_SIZE];/* Driver info block encoding buffer*/
+    uint8_t        *p = NULL;                   /* Ptr into encoding buffers        */
+    unsigned        i;                          /* Index variable                   */
+    unsigned        chksum;                     /* Checksum temporary variable      */
+    size_t          superblock_size;            /* Size of superblock, in bytes     */
+    size_t          driver_size;                /* Size of driver info block (bytes)*/
+    char            driver_name[9];             /* Name of driver, for driver info block */
+    unsigned        super_vers;                 /* Super block version              */
+    unsigned        freespace_vers;             /* Freespace info version           */
+    unsigned        obj_dir_vers;               /* Object header info version       */
+    unsigned        share_head_vers;            /* Shared header info version       */
+    H5P_genplist_t *plist;                      /* Property list                    */
+    herr_t          ret_value = SUCCEED;
+
+    /* Encoding */
+    FUNC_ENTER_NOAPI(H5F_write_superblock, FAIL)
+
+    /* Get the shared file creation property list */
+    if (NULL == (plist = 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 super block version")
+    if (H5P_get(plist, H5F_CRT_FREESPACE_VERS_NAME, &freespace_vers) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get free space version")
+    if (H5P_get(plist, H5F_CRT_OBJ_DIR_VERS_NAME, &obj_dir_vers) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get object directory version")
+    if (H5P_get(plist, H5F_CRT_SHARE_HEAD_VERS_NAME, &share_head_vers) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get shared-header format version")
+
+    /* Encode the file super block */
+    p = sbuf;
+    HDmemcpy(p, H5F_SIGNATURE, (size_t)H5F_SIGNATURE_LEN);
+    p += H5F_SIGNATURE_LEN;
+    *p++ = (uint8_t)super_vers;
+    *p++ = (uint8_t)freespace_vers;
+    *p++ = (uint8_t)obj_dir_vers;
+    *p++ = 0;   /* reserved*/
+    *p++ = (uint8_t)share_head_vers;
+    assert (H5F_SIZEOF_ADDR(f) <= 255);
+    *p++ = (uint8_t)H5F_SIZEOF_ADDR(f);
+    assert (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, f->shared->consist_flags);    
+
+    /*
+     * Versions of the superblock >0 have the indexed storage B-tree
+     * internal 'K' value stored
+     */
+    if (super_vers > 0) {
+        UINT16ENCODE(p, f->shared->btree_k[H5B_ISTORE_ID]);
+        *p++ = 0;   /*reserved */
+        *p++ = 0;   /*reserved */
+    }
+
+    H5F_addr_encode(f, &p, f->shared->base_addr);
+    H5F_addr_encode(f, &p, f->shared->freespace_addr);
+    H5F_addr_encode(f, &p, H5FD_get_eoa(f->shared->lf));
+    H5F_addr_encode(f, &p, f->shared->driver_addr);
+    if(H5G_ent_encode(f, &p, H5G_entof(f->shared->root_grp))<0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode root group information")
+
+    H5_ASSIGN_OVERFLOW(superblock_size, p - sbuf, int, size_t);
+
+    /* Double check we didn't overrun the block (unlikely) */
+    assert(superblock_size <= sizeof(sbuf));
+
+    /* Encode the driver information block. */
+    H5_ASSIGN_OVERFLOW(driver_size, H5FD_sb_size(f->shared->lf), hsize_t, size_t);
+
+    if (driver_size > 0) {
+	driver_size += 16; /* Driver block header */
+
+        /* Double check we didn't overrun the block (unlikely) */
+	assert(driver_size <= sizeof(dbuf));
+
+        /* Encode the driver information block */
+	p = dbuf;
+
+	*p++ = HDF5_DRIVERINFO_VERSION; /* Version */
+	*p++ = 0; /* reserved */
+	*p++ = 0; /* reserved */
+	*p++ = 0; /* reserved */
+
+	/* Driver info size, excluding header */
+	UINT32ENCODE(p, driver_size - 16);
+
+	/* Encode driver-specific data */
+	if (H5FD_sb_encode(f->shared->lf, driver_name, dbuf + 16) < 0)
+	    HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information")
+
+	/* Driver name */
+	HDmemcpy(dbuf + 8, driver_name, (size_t)8);
+    } /* end if */
+
+    /* Compute super block checksum */
+    assert(sizeof(chksum) == sizeof(f->shared->super_chksum));
+
+    for (p = (uint8_t *)&chksum, chksum = 0, i = 0; i < superblock_size; ++i)
+        p[i % sizeof(f->shared->super_chksum)] ^= sbuf[i];
+
+    /* Compare with current checksums */
+    if (chksum != f->shared->super_chksum) {
+        /* Write superblock */
+        if (H5FD_write(f->shared->lf, H5FD_MEM_SUPER, dxpl_id,
+                       f->shared->super_addr, superblock_size, sbuf) < 0)
+            HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write superblock")
+
+        /* Update checksum information if different */
+        f->shared->super_chksum = chksum;
+    } /* end if */
+
+    /* Check for driver info block */
+    if (HADDR_UNDEF != f->shared->driver_addr) {
+        /* Compute driver info block checksum */
+        assert(sizeof(chksum) == sizeof(f->shared->drvr_chksum));
+
+        for (p = (uint8_t *)&chksum, chksum = 0, i = 0; i < driver_size; ++i)
+            p[i % sizeof(f->shared->drvr_chksum)] ^= dbuf[i];
+
+        /* Compare with current checksums */
+        if (chksum != f->shared->drvr_chksum) {
+            /* Write driver information block */
+            if (H5FD_write(f->shared->lf, H5FD_MEM_SUPER, dxpl_id,
+                           f->shared->base_addr + f->shared->driver_addr, driver_size, dbuf) < 0)
+                HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write driver information block")
+
+            /* Update checksum information if different */
+            f->shared->drvr_chksum = chksum;
+        } /* end if */
+    } /* end if */
+
+    /* Update the user's buffer, if given */
+    if (buf) {
+        HDmemcpy(buf, sbuf, superblock_size);
+        HDmemcpy(&buf[superblock_size], dbuf, driver_size);
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+