/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=8:tabstop=8:
*
- * Copyright (C) 2002, 2003 Cluster File Systems, Inc.
+ * GPL HEADER START
*
- * This file is part of Lustre, http://www.lustre.org.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
- * Lustre is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
*
- * Lustre is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
*
- * You should have received a copy of the GNU General Public License
- * along with Lustre; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc. All rights reserved
+ * Use is subject to license terms.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
*/
#define DEBUG_SUBSYSTEM S_CLASS
+#include <obd_class.h>
#ifdef __KERNEL__
#include <linux/kmod.h> /* for request_module() */
#include <linux/module.h>
-#include <linux/obd_class.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
-#else
+#else
#include <liblustre.h>
-#include <linux/obd_class.h>
-#include <linux/obd.h>
+#include <obd.h>
#endif
-#include <linux/lprocfs_status.h>
+#include <lprocfs_status.h>
+#include <lustre/lustre_idl.h>
-
-int mea_name2idx(struct mea *mea, char *name, int namelen)
+#ifdef __KERNEL__
+#include <linux/jbd.h>
+#ifdef HAVE_SERVER_SUPPORT
+/* LDISKFS_SB() */
+#include <linux/ldiskfs_fs.h>
+#endif
+#endif
+static int mea_last_char_hash(int count, char *name, int namelen)
{
unsigned int c;
- /* just to simplify caller code */
- if (mea == NULL)
- return 0;
+ c = name[namelen - 1];
+ if (c == 0)
+ CWARN("looks like wrong len is passed\n");
+ c = c % count;
+ return c;
+}
- if (mea->mea_count == 0)
- return 0;
+static int mea_all_chars_hash(int count, char *name, int namelen)
+{
+ unsigned int c = 0;
- /* FIXME: real hash calculation here */
- c = name[namelen - 1];
- c = c % mea->mea_count;
-
- LASSERT(c < mea->mea_count);
+ while (--namelen >= 0)
+ c += name[namelen];
+ c = c % count;
return c;
}
-int raw_name2idx(int count, const char *name, int namelen)
+#ifdef __KERNEL__
+/* This hash calculate method must be same as the lvar hash method */
+
+#define LVAR_HASH_SANDWICH (0)
+#define LVAR_HASH_TEA (1)
+#define LVAR_HASH_R5 (0)
+#define LVAR_HASH_PREFIX (0)
+
+static __u32 hash_build0(const char *name, int namelen)
{
- unsigned int c;
+ __u32 result;
+
+ if (namelen == 0)
+ return 0;
+ if (strncmp(name, ".", 1) == 0 && namelen == 1)
+ return 1;
+ if (strncmp(name, "..", 2) == 0 && namelen == 2)
+ return 2;
+
+ if (LVAR_HASH_PREFIX) {
+ result = 0;
+ strncpy((void *)&result,
+ name, min(namelen, (int)sizeof result));
+ } else {
+ struct ldiskfs_dx_hash_info hinfo;
+
+ if (LVAR_HASH_TEA)
+ hinfo.hash_version = LDISKFS_DX_HASH_TEA;
+ else
+ hinfo.hash_version = LDISKFS_DX_HASH_R5;
+ hinfo.seed = 0;
+ ldiskfsfs_dirhash(name, namelen, &hinfo);
+ result = hinfo.hash;
+ if (LVAR_HASH_SANDWICH) {
+ __u32 result2;
+
+ hinfo.hash_version = LDISKFS_DX_HASH_TEA;
+ hinfo.seed = 0;
+ ldiskfsfs_dirhash(name, namelen, &hinfo);
+ result2 = hinfo.hash;
+ result = (0xfc000000 & result2) | (0x03ffffff & result);
+ }
+ }
+
+ return result;
+}
+
+enum {
+ HASH_GRAY_AREA = 1024
+};
+
+static __u32 hash_build(const char *name, int namelen)
+{
+ __u32 hash;
+
+ hash = (hash_build0(name, namelen) << 1) & MAX_HASH_SIZE_32;
+ if (hash > MAX_HASH_SIZE_32 - HASH_GRAY_AREA)
+ hash &= HASH_GRAY_AREA - 1;
+ return hash;
+}
+
+static int mea_hash_segment(int count, const char *name, int namelen)
+{
+ __u32 hash;
+
+ LASSERT(IS_PO2(MAX_HASH_SIZE_32 + 1));
+
+ hash = hash_build(name, namelen) / (MAX_HASH_SIZE_32 / count);
+ LASSERTF(hash < count, "hash %x count %d \n", hash, count);
+
+ return hash;
+}
+#else
+static int mea_hash_segment(int count, char *name, int namelen)
+{
+ return 0;
+}
+#endif
+int raw_name2idx(int hashtype, int count, const char *name, int namelen)
+{
+ unsigned int c = 0;
LASSERT(namelen > 0);
if (count <= 1)
return 0;
-
- /* FIXME: real hash calculation here */
- c = name[namelen - 1];
- c = c % count;
+ switch (hashtype) {
+ case MEA_MAGIC_LAST_CHAR:
+ c = mea_last_char_hash(count, (char *)name, namelen);
+ break;
+ case MEA_MAGIC_ALL_CHARS:
+ c = mea_all_chars_hash(count, (char *)name, namelen);
+ break;
+ case MEA_MAGIC_HASH_SEGMENT:
+ c = mea_hash_segment(count, (char *)name, namelen);
+ break;
+ default:
+ CERROR("Unknown hash type 0x%x\n", hashtype);
+ }
+ LASSERT(c < count);
return c;
}
+int mea_name2idx(struct lmv_stripe_md *mea, const char *name, int namelen)
+{
+ unsigned int c;
+
+ LASSERT(mea && mea->mea_count);
+
+ c = raw_name2idx(mea->mea_magic, mea->mea_count, name, namelen);
+
+ LASSERT(c < mea->mea_count);
+ return c;
+}