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authorQuincey Koziol <koziol@hdfgroup.org>2011-02-22 19:37:06 (GMT)
committerQuincey Koziol <koziol@hdfgroup.org>2011-02-22 19:37:06 (GMT)
commit727b687ae6c80c9854cb53814fa1c12f27c2994c (patch)
treefabe359aaddbe3b4d1e2bb58ceb3b94311d66a1c /src/H5Fefc.c
parent25486d50895fa4a30809d289b9aff4de583a9b84 (diff)
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[svn-r20146] Description:
Bring r19714:20145 from trunk to revise_chunks branch. Tested on: FreeBSD/32 6.3 (duty) in debug mode FreeBSD/64 6.3 (liberty) w/C++ & FORTRAN, in debug mode Linux/32 2.6 (jam) w/PGI compilers, w/default API=1.8.x, w/C++ & FORTRAN, w/threadsafe, in debug mode Linux/64-amd64 2.6 (amani) 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, w/threadsafe, in production mode Linux/PPC 2.6 (heiwa) w/C++ & FORTRAN, w/threadsafe, in debug mode Linux/64-amd64 2.6 (abe) w/parallel, w/FORTRAN, in debug mode Mac OS X/32 10.6.6 (amazon) in debug mode Mac OS X/32 10.6.6 (amazon) w/C++ & FORTRAN, w/threadsafe, in production mode
Diffstat (limited to 'src/H5Fefc.c')
-rw-r--r--src/H5Fefc.c951
1 files changed, 951 insertions, 0 deletions
diff --git a/src/H5Fefc.c b/src/H5Fefc.c
new file mode 100644
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--- /dev/null
+++ b/src/H5Fefc.c
@@ -0,0 +1,951 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group. *
+ * 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://hdfgroup.org/HDF5/doc/Copyright.html. If you do not have *
+ * access to either file, you may request a copy from help@hdfgroup.org. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created: H5Defc.c
+ * December 13, 2010
+ * Neil Fortner <nfortne2@hdfgroup.org>
+ *
+ * Purpose: External file caching routines - implements a
+ * cache of external files to minimize the number of
+ * file opens and closes.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#define H5F_PACKAGE /*suppress error about including H5Fpkg */
+
+
+/* Packages needed by this file... */
+#include "H5private.h" /* Generic Functions */
+#include "H5Eprivate.h" /* Error handling */
+#include "H5Fpkg.h" /* File access */
+#include "H5MMprivate.h" /* Memory management */
+#include "H5Pprivate.h" /* Property lists */
+
+
+/* Special values for the "tag" field below */
+#define H5F_EFC_TAG_DEFAULT -1
+#define H5F_EFC_TAG_LOCK -2
+#define H5F_EFC_TAG_CLOSE -3
+#define H5F_EFC_TAG_DONTCLOSE -4
+
+/* Structure for each entry in a file's external file cache */
+typedef struct H5F_efc_ent_t {
+ char *name; /* Name of the file */
+ H5F_t *file; /* File object */
+ struct H5F_efc_ent_t *LRU_next; /* Next item in LRU list */
+ struct H5F_efc_ent_t *LRU_prev; /* Previous item in LRU list */
+ unsigned nopen; /* Number of times this file is currently opened by an EFC client */
+} H5F_efc_ent_t;
+
+/* Structure for a shared file struct's external file cache */
+struct H5F_efc_t {
+ H5SL_t *slist; /* Skip list of cached external files */
+ H5F_efc_ent_t *LRU_head; /* Head of LRU list. This is the least recently used file */
+ H5F_efc_ent_t *LRU_tail; /* Tail of LRU list. This is the most recently used file */
+ unsigned nfiles; /* Size of the external file cache */
+ unsigned max_nfiles; /* Maximum size of the external file cache */
+ unsigned nrefs; /* Number of times this file appears in another file's EFC */
+ int tag; /* Temporary variable used by H5F_efc_try_close() */
+ H5F_file_t *tmp_next; /* Next file in temporary list used by H5F_efc_try_close() */
+};
+
+/* Private prototypes */
+static herr_t H5F_efc_remove_ent(H5F_efc_t *efc, H5F_efc_ent_t *ent);
+static void H5F_efc_try_close_tag1(H5F_file_t *sf, H5F_file_t **tail);
+static void H5F_efc_try_close_tag2(H5F_file_t *sf, H5F_file_t **tail);
+
+/* Free lists */
+H5FL_DEFINE_STATIC(H5F_efc_ent_t);
+H5FL_DEFINE_STATIC(H5F_efc_t);
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_efc_create
+ *
+ * Purpose: Allocate and initialize a new external file cache object,
+ * which can the be used to cache open external files.
+ * the object must be freed with H5F_efc_destroy.
+ *
+ * Return: Pointer to new external file cache object on success
+ * NULL on failure
+ *
+ * Programmer: Neil Fortner
+ * Tuesday, December 14, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+H5F_efc_t *
+H5F_efc_create(unsigned max_nfiles)
+{
+ H5F_efc_t *efc = NULL; /* EFC object */
+ H5F_efc_t *ret_value; /* Return value */
+
+ FUNC_ENTER_NOAPI(H5F_efc_create, NULL)
+
+ /* Sanity checks */
+ HDassert(max_nfiles > 0);
+
+ /* Allocate EFC struct */
+ if(NULL == (efc = H5FL_CALLOC(H5F_efc_t)))
+ HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+
+ /* Initialize maximum number of files */
+ efc->max_nfiles = max_nfiles;
+
+ /* Initialize temporary ref count */
+ efc->tag = H5F_EFC_TAG_DEFAULT;
+
+ /* Set the return value */
+ ret_value = efc;
+
+done:
+ if(ret_value == NULL && efc)
+ efc = H5FL_FREE(H5F_efc_t, efc);
+
+ FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_efc_create() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_efc_open
+ *
+ * Purpose: Opens a file using the external file cache. The target
+ * file is added to the external file cache of the parent
+ * if it is not already present. If the target file is in
+ * the parent's EFC, simply returns the target file. When
+ * the file object is no longer in use, it should be closed
+ * with H5F_efc_close (will not actually close the file
+ * until it is evicted from the EFC).
+ *
+ * Return: Pointer to open file on success
+ * NULL on failure
+ *
+ * Programmer: Neil Fortner
+ * Tuesday, December 14, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+H5F_t *
+H5F_efc_open(H5F_t *parent, const char *name, unsigned flags, hid_t fcpl_id,
+ hid_t fapl_id, hid_t dxpl_id)
+{
+ H5F_efc_t *efc = NULL; /* External file cache for parent file */
+ H5F_efc_ent_t *ent = NULL; /* Entry for target file in efc */
+ hbool_t open_file = FALSE; /* Whether ent->file needs to be closed in case of error */
+ H5F_t *ret_value; /* Return value */
+
+ FUNC_ENTER_NOAPI_NOINIT(H5F_efc_open)
+
+ /* Sanity checks */
+ HDassert(parent);
+ HDassert(parent->shared);
+ HDassert(name);
+
+ /* Get external file cache */
+ efc = parent->shared->efc;
+
+ /* Check if the EFC exists. If it does not, just call H5F_open(). We
+ * support this so clients do not have to make 2 different calls depending
+ * on the state of the efc. */
+ if(!efc) {
+ if(NULL == (ret_value = H5F_open(name, flags, fcpl_id, fapl_id,
+ dxpl_id)))
+ HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "can't open file")
+
+ /* Increment the number of open objects to prevent the file from being
+ * closed out from under us - "simulate" having an open file id. Note
+ * that this behaviour replaces the calls to H5F_incr_nopen_objs() and
+ * H5F_decr_nopen_objs() in H5L_extern_traverse(). */
+ ret_value->nopen_objs++;
+
+ HGOTO_DONE(ret_value)
+ } /* end if */
+
+ /* Search the skip list for name if the skip list exists, create the skip
+ * list otherwise */
+ if(efc->slist) {
+ if(efc->nfiles > 0)
+ ent = (H5F_efc_ent_t *)H5SL_search(efc->slist, name);
+ } /* end if */
+ else {
+ HDassert(efc->nfiles == 0);
+ if(NULL == (efc->slist = H5SL_create(H5SL_TYPE_STR)))
+ HGOTO_ERROR(H5E_FILE, H5E_CANTCREATE, NULL, "can't create skip list")
+ } /* end else */
+
+ /* If we found the file update the LRU list and return the cached file,
+ * otherwise open the file and cache it */
+ if(ent) {
+ HDassert(efc->LRU_head);
+ HDassert(efc->LRU_tail);
+
+ /* Move ent to the head of the LRU list, if it is not already there */
+ if(ent->LRU_prev) {
+ HDassert(efc->LRU_head != ent);
+
+ /* Remove from current position. Note that once we touch the LRU
+ * list we cannot revert to the previous state. Make sure there can
+ * be no errors between when we first touch the LRU list and when
+ * the cache is in a consistent state! */
+ if(ent->LRU_next)
+ ent->LRU_next->LRU_prev = ent->LRU_prev;
+ else {
+ HDassert(efc->LRU_tail == ent);
+ efc->LRU_tail = ent->LRU_prev;
+ } /* end else */
+ ent->LRU_prev->LRU_next = ent->LRU_next;
+
+ /* Add to head of LRU list */
+ ent->LRU_next = efc->LRU_head;
+ ent->LRU_next->LRU_prev = ent;
+ ent->LRU_prev = NULL;
+ efc->LRU_head = ent;
+ } /* end if */
+
+ /* Mark the file as open */
+ ent->nopen++;
+ } /* end if */
+ else {
+ /* Check if we need to evict something */
+ if(efc->nfiles == efc->max_nfiles) {
+ /* Search for an unopened file from the tail */
+ for(ent = efc->LRU_tail; ent && ent->nopen; ent = ent->LRU_prev);
+
+ /* Evict the file if found, otherwise just open the target file and
+ * do not add it to cache */
+ if(ent) {
+ if(H5F_efc_remove_ent(efc, ent) < 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTREMOVE, NULL, "can't remove entry from external file cache")
+
+ /* Do not free ent, we will recycle it below */
+ } /* end if */
+ else {
+ /* Cannot cache file, just open file and return */
+ if(NULL == (ret_value = H5F_open(name, flags, fcpl_id, fapl_id,
+ dxpl_id)))
+ HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "can't open file")
+
+ /* Increment the number of open objects to prevent the file from
+ * being closed out from under us - "simulate" having an open
+ * file id */
+ ret_value->nopen_objs++;
+
+ HGOTO_DONE(ret_value)
+ } /* end else */
+ } /* end if */
+ else
+ /* Allocate new entry */
+ if(NULL == (ent = H5FL_MALLOC(H5F_efc_ent_t)))
+ HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+
+ /* Build new entry */
+ if(NULL == (ent->name = H5MM_strdup(name)))
+ HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+
+ /* Open the file */
+ if(NULL == (ent->file = H5F_open(name, flags, fcpl_id, fapl_id,
+ dxpl_id)))
+ HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "can't open file")
+ open_file = TRUE;
+
+ /* Increment the number of open objects to prevent the file from being
+ * closed out from under us - "simulate" having an open file id */
+ ent->file->nopen_objs++;
+
+ /* Add the file to the cache */
+ /* Skip list */
+ if(H5SL_insert(efc->slist, ent, ent->name) < 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTINSERT, NULL, "can't insert entry into skip list")
+
+ /* Add to head of LRU list and update tail if necessary */
+ ent->LRU_next = efc->LRU_head;
+ if(ent->LRU_next)
+ ent->LRU_next->LRU_prev = ent;
+ ent->LRU_prev = NULL;
+ efc->LRU_head = ent;
+ if(!efc->LRU_tail) {
+ HDassert(!ent->LRU_next);
+ efc->LRU_tail = ent;
+ } /* end if */
+
+ /* Mark the file as open */
+ ent->nopen = 1;
+
+ /* Update nfiles and nrefs */
+ efc->nfiles++;
+ if(ent->file->shared->efc)
+ ent->file->shared->efc->nrefs++;
+ } /* end else */
+
+ HDassert(ent);
+ HDassert(ent->file);
+ HDassert(ent->name);
+ HDassert(ent->nopen);
+
+ /* Set the return value */
+ ret_value = ent->file;
+
+done:
+ if(!ret_value)
+ if(ent) {
+ if(open_file) {
+ ent->file->nopen_objs--;
+ if(H5F_try_close(ent->file) < 0)
+ HDONE_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, NULL, "can't close external file")
+ } /* end if */
+ ent->name = (char *)H5MM_xfree(ent->name);
+ ent = H5FL_FREE(H5F_efc_ent_t, ent);
+ } /* end if */
+
+ FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_efc_open() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_efc_close
+ *
+ * Purpose: Closes (unlocks) a file opened using the external file
+ * cache. The target file is not immediately closed unless
+ * there is no external file cache for the parent file.
+ *
+ * Return: Non-negative on success
+ * Negative on failure
+ *
+ * Programmer: Neil Fortner
+ * Wednesday, December 15, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_efc_close(H5F_t *parent, H5F_t *file)
+{
+ H5F_efc_t *efc = NULL; /* External file cache for parent file */
+ H5F_efc_ent_t *ent = NULL; /* Entry for target file in efc */
+ herr_t ret_value = SUCCEED; /* Return value */
+
+ FUNC_ENTER_NOAPI_NOINIT(H5F_efc_close)
+
+ /* Sanity checks */
+ HDassert(parent);
+ HDassert(parent->shared);
+ HDassert(file);
+ HDassert(file->shared);
+
+ /* Get external file cache */
+ efc = parent->shared->efc;
+
+ /* Check if the EFC exists. If it does not, just call H5F_try_close(). We
+ * support this so clients do not have to make 2 different calls depending
+ * on the state of the efc. */
+ if(!efc) {
+ file->nopen_objs--;
+ if(H5F_try_close(file) < 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "can't close external file")
+
+ HGOTO_DONE(SUCCEED)
+ } /* end if */
+
+ /* Scan the parent's LRU list from the head to file file. We do this
+ * instead of a skip list lookup because the file will almost always be at
+ * the head. In the unlikely case that the file is not found, just call
+ * H5F_try_close(). This could happen if the EFC was full of open files
+ * when the file was opened. */
+ for(ent = efc->LRU_head; ent && ent->file != file; ent = ent->LRU_next);
+ if(!ent) {
+ file->nopen_objs--;
+ if(H5F_try_close(file) < 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "can't close external file")
+ } /* end if */
+ else
+ /* Reduce the open count on this entry */
+ ent->nopen--;
+
+done:
+ FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_efc_close() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_efc_max_nfiles
+ *
+ * Purpose: Returns the maximum number of files in the provided
+ * external file cache.
+ *
+ * Return: Maximum number of files (never fails)
+ *
+ * Programmer: Neil Fortner
+ * Wednesday, December 15, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+unsigned
+H5F_efc_max_nfiles(H5F_efc_t *efc)
+{
+ FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5F_efc_max_nfiles)
+
+ HDassert(efc);
+ HDassert(efc->max_nfiles > 0);
+
+ FUNC_LEAVE_NOAPI(efc->max_nfiles)
+} /* end H5F_efc_max_nfiles */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_efc_release
+ *
+ * Purpose: Releases the external file cache, potentially closing any
+ * cached files unless they are held open from somewhere
+ * else (or are currently opened by a client).
+ *
+ * Return: Non-negative on success
+ * Negative on failure
+ *
+ * Programmer: Neil Fortner
+ * Wednesday, December 15, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_efc_release(H5F_efc_t *efc)
+{
+ H5F_efc_ent_t *ent = NULL; /* EFC entry */
+ H5F_efc_ent_t *prev_ent = NULL; /* Previous EFC entry */
+ herr_t ret_value = SUCCEED; /* Return value */
+
+ FUNC_ENTER_NOAPI_NOINIT(H5F_efc_release)
+
+ /* Sanity checks */
+ HDassert(efc);
+
+ /* Lock the EFC to prevent manipulation of the EFC wile we are releasing it.
+ * The EFC should never be locked when we enter this function because that
+ * would require a cycle, a cycle would necessarily invoke
+ * H5F_efc_try_close(), and that function checks the status of the lock
+ * before calling this one. */
+ HDassert((efc->tag == H5F_EFC_TAG_DEFAULT)
+ || (efc->tag == H5F_EFC_TAG_CLOSE));
+ efc->tag = H5F_EFC_TAG_LOCK;
+
+ /* Walk down the LRU list, releasing any files that are not opened by an EFC
+ * client */
+ ent = efc->LRU_head;
+ while(ent)
+ if(!ent->nopen) {
+ if(H5F_efc_remove_ent(efc, ent) < 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTREMOVE, FAIL, "can't remove entry from external file cache")
+
+ /* Free the entry and move to next entry in LRU list */
+ prev_ent = ent;
+ ent = ent->LRU_next;
+ prev_ent = H5FL_FREE(H5F_efc_ent_t, prev_ent);
+ } /* end if */
+ else
+ /* Can't release file because it's open; just advance the pointer */
+ ent = ent->LRU_next;
+
+ /* Reset tag. No need to reset to CLOSE if that was the original tag, as in
+ * that case the file must be getting closed anyways. */
+ efc->tag = H5F_EFC_TAG_DEFAULT;
+
+done:
+ FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5F_efc_release() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_efc_destroy
+ *
+ * Purpose: Frees an external file cache object, releasing it first
+ * if necessary. If it cannot be fully released, for example
+ * if there are open files, returns an error.
+ *
+ * Return: Non-negative on success
+ * Negative on failure
+ *
+ * Programmer: Neil Fortner
+ * Wednesday, December 15, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_efc_destroy(H5F_efc_t *efc)
+{
+ herr_t ret_value = SUCCEED; /* Return value */
+
+ FUNC_ENTER_NOAPI_NOINIT(H5F_efc_destroy)
+
+ /* Sanity checks */
+ HDassert(efc);
+
+ if(efc->nfiles > 0) {
+ /* Release (clear) the efc */
+ if(H5F_efc_release(efc) < 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "can't release external file cache")
+
+ /* If there are still cached files, return an error */
+ if(efc->nfiles > 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't destroy EFC after incomplete release")
+ } /* end if */
+
+ HDassert(efc->nfiles == 0);
+ HDassert(efc->LRU_head == NULL);
+ HDassert(efc->LRU_tail == NULL);
+
+ /* Close skip list */
+ if(efc->slist)
+ if(H5SL_close(efc->slist) < 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't close skip list")
+
+ /* Free EFC object */
+ (void)H5FL_FREE(H5F_efc_t, efc);
+
+done:
+ FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5F_efc_destroy() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_efc_remove_ent
+ *
+ * Purpose: Removes the specified entry from the specified EFC,
+ * closing the file if requested. Does not free the entry.
+ *
+ * Return: Non-negative on success
+ * Negative on failure
+ *
+ * Programmer: Neil Fortner
+ * Wednesday, December 15, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5F_efc_remove_ent(H5F_efc_t *efc, H5F_efc_ent_t *ent)
+{
+ herr_t ret_value = SUCCEED; /* Return value */
+
+ FUNC_ENTER_NOAPI_NOINIT(H5F_efc_remove_ent)
+
+ /* Sanity checks */
+ HDassert(efc);
+ HDassert(efc->slist);
+ HDassert(ent);
+
+ /* Remove from skip list */
+ if(ent != H5SL_remove(efc->slist, ent->name))
+ HGOTO_ERROR(H5E_FILE, H5E_CANTDELETE, FAIL, "can't delete entry from skip list")
+
+ /* Remove from LRU list */
+ if(ent->LRU_next)
+ ent->LRU_next->LRU_prev = ent->LRU_prev;
+ else {
+ HDassert(efc->LRU_tail == ent);
+ efc->LRU_tail = ent->LRU_prev;
+ } /* end else */
+ if(ent->LRU_prev)
+ ent->LRU_prev->LRU_next = ent->LRU_next;
+ else {
+ HDassert(efc->LRU_head == ent);
+ efc->LRU_head = ent->LRU_next;
+ } /* end else */
+
+ /* Update nfiles and nrefs */
+ efc->nfiles--;
+ if(ent->file->shared->efc)
+ ent->file->shared->efc->nrefs--;
+
+ /* Free the name */
+ ent->name = (char *)H5MM_xfree(ent->name);
+
+ /* Close the file. Note that since H5F_t structs returned from H5F_open()
+ * are *always* unique, there is no need to reference count this struct.
+ * However we must still manipulate the nopen_objs field to prevent the file
+ * from being closed out from under us. */
+ ent->file->nopen_objs--;
+ if(H5F_try_close(ent->file) < 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "can't close external file")
+ ent->file = NULL;
+
+done:
+ FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_efc_remove_ent() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_efc_try_close_tag1
+ *
+ * Purpose: Recursively traverse the EFC tree, keeping a temporary
+ * reference count on each file that assumes all reachable
+ * files will eventually be closed.
+ *
+ * Return: void (never fails)
+ *
+ * Programmer: Neil Fortner
+ * Monday, January 10, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static void
+H5F_efc_try_close_tag1(H5F_file_t *sf, H5F_file_t **tail)
+{
+ H5F_efc_ent_t *ent = NULL; /* EFC entry */
+ H5F_file_t *esf; /* Convenience pointer to ent->file->shared */
+
+ FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5F_efc_try_close_tag1)
+
+ /* Sanity checks */
+ HDassert(sf);
+ HDassert(sf->efc);
+ HDassert((sf->efc->tag > 0) || (sf->nrefs == sf->efc->nrefs));
+ HDassert(sf->efc->tag != H5F_EFC_TAG_LOCK);
+ HDassert(tail);
+ HDassert(*tail);
+
+ /* Recurse into this file's cached files */
+ for(ent = sf->efc->LRU_head; ent; ent = ent->LRU_next) {
+ esf = ent->file->shared;
+
+ if(esf->efc) {
+ /* If tag were 0, that would mean there are more actual references
+ * than are counted by nrefs */
+ HDassert(esf->efc->tag != 0);
+
+ /* If tag has been set, we have already visited this file so just
+ * decrement tag and continue */
+ if(esf->efc->tag > 0)
+ esf->efc->tag--;
+ /* If there are references that are not from an EFC, it will never
+ * be possible to close the file. Just continue. Also continue if
+ * the EFC is locked or the file is open (through the EFC). Note
+ * that the reference counts will never match for the root file, but
+ * that's ok because the root file will always have a tag and enter
+ * the branch above. */
+ else if((esf->nrefs == esf->efc->nrefs)
+ && (esf->efc->tag != H5F_EFC_TAG_LOCK) && !(ent->nopen)) {
+ /* If we get here, this file's "tmp_next" pointer must be NULL
+ */
+ HDassert(esf->efc->tmp_next == NULL);
+
+ /* If nrefs > 1, Add this file to the list of files with nrefs >
+ * 1 and initialize tag to the number of references (except this
+ * one) */
+ if(esf->nrefs > 1) {
+ (*tail)->efc->tmp_next = esf;
+ *tail = esf;
+ esf->efc->tag = (int)esf->nrefs - 1;
+ } /* end if */
+
+ /* Recurse into the entry */
+ H5F_efc_try_close_tag1(ent->file->shared, tail);
+ } /* end if */
+ } /* end if */
+ } /* end for */
+
+ FUNC_LEAVE_NOAPI_VOID
+} /* end H5F_efc_try_close_tag1() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_efc_try_close_tag2
+ *
+ * Purpose: Recuresively mark all files reachable through this one as
+ * uncloseable, and add newly uncloseable files to the tail
+ * of the provided linked list.
+ *
+ * Return: void (never fails)
+ *
+ * Programmer: Neil Fortner
+ * Monday, January 10, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static void
+H5F_efc_try_close_tag2(H5F_file_t *sf, H5F_file_t **tail)
+{
+ H5F_efc_ent_t *ent = NULL; /* EFC entry */
+ H5F_file_t *esf; /* Convenience pointer to ent->file->shared */
+
+ FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5F_efc_try_close_tag2)
+
+ /* Sanity checks */
+ HDassert(sf);
+ HDassert(sf->efc);
+
+ /* Recurse into this file's cached files */
+ for(ent = sf->efc->LRU_head; ent; ent = ent->LRU_next) {
+ esf = ent->file->shared;
+
+ /* Only recurse if the file is tagged CLOSE or DEFAULT. If it is tagged
+ * DONTCLOSE, we have already visited this file *or* it will be the
+ * start point of another iteration. No files should be tagged with a
+ * nonegative value at this point. If it is tagged as DEFAULT, we must
+ * apply the same conditions as in cb1 above for recursion in order to
+ * make sure we do not go off into somewhere cb1 didn't touch. The
+ * root file should never be tagged DEFAULT here, so the reference check
+ * is still appropriate. */
+ if((esf->efc) && ((esf->efc->tag == H5F_EFC_TAG_CLOSE)
+ || ((esf->efc->tag == H5F_EFC_TAG_DEFAULT)
+ && (esf->nrefs == esf->efc->nrefs) && !(ent->nopen)))) {
+ /* tag should always be CLOSE is nrefs > 1 or DEFAULT if nrefs == 1
+ * here */
+ HDassert(((esf->nrefs > 1)
+ && ((esf->efc->tag == H5F_EFC_TAG_CLOSE)))
+ || ((esf->nrefs == 1)
+ && (esf->efc->tag == H5F_EFC_TAG_DEFAULT)));
+
+ /* If tag is set to DONTCLOSE, we have already visited this file
+ * *or* it will be the start point of another iteration so just
+ * continue */
+ if(esf->efc->tag != H5F_EFC_TAG_DONTCLOSE) {
+ /* If tag is CLOSE, set to DONTCLOSE and add to the list of
+ * uncloseable files. */
+ if(esf->efc->tag == H5F_EFC_TAG_CLOSE) {
+ esf->efc->tag = H5F_EFC_TAG_DONTCLOSE;
+ esf->efc->tmp_next = NULL;
+ (*tail)->efc->tmp_next = esf;
+ *tail = esf;
+ } /* end if */
+
+ /* Recurse into the entry */
+ H5F_efc_try_close_tag2(esf, tail);
+ } /* end if */
+ } /* end if */
+ } /* end for */
+
+ FUNC_LEAVE_NOAPI_VOID
+} /* end H5F_efc_try_close_tag2() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_efc_try_close
+ *
+ * Purpose: Attempts to close the provided (shared) file by checking
+ * to see if the releasing the EFC would cause its reference
+ * count to drop to 0. Necessary to handle the case where
+ * chained EFCs form a cycle. Note that this function does
+ * not actually close the file (though it closes all children
+ * as appropriate), as that is left up to the calling
+ * function H5F_try_close().
+ *
+ * Because H5F_try_close() has no way of telling if it is
+ * called recursively from within this function, this
+ * function serves as both the root of iteration and the
+ * "callback" for the final pass (the one where the files are
+ * actually closed). The code for the callback case is at
+ * the top of this function; luckily it only consists of a
+ * (possible) call to H5F_efc_release().
+ *
+ * The algorithm basically consists of 3 passes over the EFC
+ * tree. The first pass assumes that every reachable file is
+ * closed, and keeps track of what the final reference count
+ * would be for every reachable file. The files are then
+ * tagged as either closeable or uncloseable based on whether
+ * this reference count drops to 0.
+ *
+ * The second pass initiates a traversal from each file
+ * marked as uncloseable in the first pass, and marks every
+ * file reachable from the initial uncloseable file as
+ * uncloseable. This eliminates files that were marked as
+ * closeable only because the first pass assumed that an
+ * uncloseable file would be closed.
+ *
+ * The final pass exploits the H5F_efc_release()->
+ * H5F_efc_remove_ent()->H5F_try_close()->H5F_efc_try_close()
+ * calling chain to recursively close the tree, but only the
+ * files that are still marked as closeable. All files
+ * marked as closeable have their EFCs released, and will
+ * eventually be closed when their last parent EFC is
+ * released (the last part is guaranteed to be true by the
+ * first 2 passes).
+ *
+ * Return: Non-negative on success
+ * Negative on failure
+ *
+ * Programmer: Neil Fortner
+ * Thursday, January 6, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_efc_try_close(H5F_t *f)
+{
+ H5F_file_t *tail; /* Tail of linked list of found files. Head will be f->shared. */
+ H5F_file_t *uncloseable_head = NULL; /* Head of linked list of files found to be uncloseable by the first pass */
+ H5F_file_t *uncloseable_tail = NULL; /* Tail of linked list of files found to be uncloseable by the first pass */
+ H5F_file_t *sf; /* Temporary file pointer */
+ H5F_file_t *next; /* Temporary file pointer */
+ herr_t ret_value = SUCCEED; /* Return value */
+
+ FUNC_ENTER_NOAPI_NOINIT(H5F_efc_try_close)
+
+ /* Sanity checks */
+ HDassert(f);
+ HDassert(f->shared);
+ HDassert(f->shared->efc);
+ HDassert(f->shared->nrefs > f->shared->efc->nrefs);
+ HDassert(f->shared->nrefs > 1);
+ HDassert(f->shared->efc->tag < 0);
+
+ if(f->shared->efc->tag == H5F_EFC_TAG_CLOSE) {
+ /* We must have reentered this function, and we should close this file.
+ * In actuality, we just release the EFC, the recursion should
+ * eventually reduce this file's reference count to 1 (though possibly
+ * not from this call to H5F_efc_release()). */
+ if(H5F_efc_release(f->shared->efc) < 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "can't release external file cache")
+
+ /* If we marked the file as closeable, there must be no open files in
+ * its EFC. This is because, in order to close an open child file, the
+ * client must keep a copy of the parent file open. The algorithm
+ * detect that the parent file is open (directly or through an EFC) and
+ * refuse to close it. Verify that all files were released from this
+ * EFC (i.e. none were open). */
+ HDassert(f->shared->efc->nfiles == 0);
+
+ HGOTO_DONE(SUCCEED)
+ } /* end if */
+
+ /* Conditions where we should not do anything and just return immediately */
+ /* If there are references that are not from an EFC or f, it will never
+ * be possible to close the file. Just return. Note that this holds true
+ * for the case that this file is being closed through H5F_efc_release()
+ * because that function (through H5F_efc_remove_ent()) decrements the EFC
+ * reference count before it calls H5F_try_close(). This may occur if this
+ * function is reentered. */
+ /* If the tag is H5F_EFC_TAG_DONTCLOSE, then we have definitely reentered
+ * this function, and this file has been marked as uncloseable, so we should
+ * not close/release it */
+ /* If nfiles is 0, then there is nothing to do. Just return. This may also
+ * occur on reentry (for example if this file was previously released). */
+ if((f->shared->nrefs != f->shared->efc->nrefs + 1)
+ || (f->shared->efc->tag == H5F_EFC_TAG_DONTCLOSE)
+ || (f->shared->efc->nfiles == 0))
+ /* We must have reentered this function, and we should not close this
+ * file. Just return. */
+ HGOTO_DONE(SUCCEED)
+
+ /* If the file EFC were locked, that should always mean that there exists
+ * a reference to this file that is not in an EFC (it may have just been
+ * removed from an EFC), and should have been caught by the above check */
+ /* If we get here then we must be beginning a new run. Make sure that the
+ * temporary variables in f->shared->efc are at the default value */
+ HDassert(f->shared->efc->tag == H5F_EFC_TAG_DEFAULT);
+ HDassert(f->shared->efc->tmp_next == NULL);
+
+ /* Set up linked list for traversal into EFC tree. f->shared is guaranteed
+ * to always be at the head. */
+ tail = f->shared;
+
+ /* Set up temporary reference count on root file */
+ f->shared->efc->tag = (int)f->shared->efc->nrefs;
+
+ /* First Pass: simulate closing all files reachable from this one, use "tag"
+ * field to keep track of final reference count for each file (including
+ * this one). Keep list of files with starting reference count > 1 (head is
+ * f->shared). */
+ H5F_efc_try_close_tag1(f->shared, &tail);
+
+ /* Check if f->shared->efc->tag dropped to 0. If it did not,
+ * we cannot close anything. Just reset temporary values and return. */
+ if(f->shared->efc->tag > 0) {
+ sf = f->shared;
+ while(sf) {
+ next = sf->efc->tmp_next;
+ sf->efc->tag = H5F_EFC_TAG_DEFAULT;
+ sf->efc->tmp_next = NULL;
+ sf = next;
+ } /* end while */
+ HGOTO_DONE(SUCCEED)
+ } /* end if */
+
+ /* Run through the linked list , separating into two lists, one with tag ==
+ * 0 and one with tag > 0. Mark them as either H5F_EFC_TAG_CLOSE or
+ * H5F_EFC_TAG_DONTCLOSE as appropriate. */
+ sf = f->shared;
+ tail = NULL;
+ while(sf) {
+ HDassert(sf->efc->tag >= 0);
+ next = sf->efc->tmp_next;
+ if(sf->efc->tag > 0) {
+ /* Remove from main list */
+ HDassert(tail);
+ tail->efc->tmp_next = sf->efc->tmp_next;
+ sf->efc->tmp_next = NULL;
+
+ /* Add to uncloseable list */
+ if(!uncloseable_head)
+ uncloseable_head = sf;
+ else
+ uncloseable_tail->efc->tmp_next = sf;
+ uncloseable_tail = sf;
+
+ /* Mark as uncloseable */
+ sf->efc->tag = H5F_EFC_TAG_DONTCLOSE;
+ } /* end if */
+ else {
+ sf->efc->tag = H5F_EFC_TAG_CLOSE;
+ tail = sf;
+ } /* end else */
+ sf = next;
+ } /* end while */
+
+ /* Second pass: Determine which of the reachable files found in pass 1
+ * cannot be closed by releasing the root file's EFC. Run through the
+ * uncloseable list, for each item traverse the files reachable through the
+ * EFC, mark the file as uncloseable, and add it to the list of uncloseable
+ * files (for cleanup). Use "tail" to store the original uncloseable tail
+ * so we know when to stop. We do not need to keep track of the closeable
+ * list any more. */
+ sf = uncloseable_head;
+ if(sf) {
+ tail = uncloseable_tail;
+ HDassert(tail);
+ while(sf != tail->efc->tmp_next) {
+ H5F_efc_try_close_tag2(sf, &uncloseable_tail);
+ sf = sf->efc->tmp_next;
+ } /* end while */
+ } /* end if */
+
+ /* If the root file's tag is still H5F_EFC_TAG_CLOSE, release its EFC. This
+ * should start the recursive release that should close all closeable files.
+ * Also, see the top of this function. */
+ if(f->shared->efc->tag == H5F_EFC_TAG_CLOSE) {
+ if(H5F_efc_release(f->shared->efc) < 0)
+ HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "can't release external file cache")
+
+ /* Make sure the file's reference count is now 1 and will be closed by
+ * H5F_dest(). */
+ HDassert(f->shared->nrefs == 1);
+ } /* end if */
+
+ /* Clean up uncloseable files (reset tag and tmp_next). All closeable files
+ * should have been closed, and therefore do not need to be cleaned up. */
+ if(uncloseable_head) {
+ sf = uncloseable_head;
+ while(sf) {
+ next = sf->efc->tmp_next;
+ HDassert(sf->efc->tag == H5F_EFC_TAG_DONTCLOSE);
+ sf->efc->tag = H5F_EFC_TAG_DEFAULT;
+ sf->efc->tmp_next = NULL;
+ sf = next;
+ } /* end while */
+ } /* end if */
+
+done:
+ FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_efc_try_close() */
+