1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
4 * Copyright (C) 2002, 2003 Cluster File Systems, Inc.
6 * This file is part of Lustre, http://www.lustre.org.
8 * Lustre is free software; you can redistribute it and/or
9 * modify it under the terms of version 2 of the GNU General Public
10 * License as published by the Free Software Foundation.
12 * Lustre is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with Lustre; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #define DEBUG_SUBSYSTEM S_CLASS
24 #include <linux/kmod.h> /* for request_module() */
25 #include <linux/module.h>
26 #include <obd_class.h>
27 #include <linux/random.h>
28 #include <linux/slab.h>
29 #include <linux/pagemap.h>
31 #include <liblustre.h>
32 #include <obd_class.h>
35 #include <lprocfs_status.h>
36 #include <lustre/lustre_idl.h>
39 #include <linux/jbd.h>
41 #include <linux/ldiskfs_fs.h>
43 static int mea_last_char_hash(int count, char *name, int namelen)
47 c = name[namelen - 1];
49 CWARN("looks like wrong len is passed\n");
54 static int mea_all_chars_hash(int count, char *name, int namelen)
58 while (--namelen >= 0)
65 /* This hash calculate method must be same as the lvar hash method */
67 #define LVAR_HASH_SANDWICH (0)
68 #define LVAR_HASH_TEA (1)
69 #define LVAR_HASH_R5 (0)
70 #define LVAR_HASH_PREFIX (0)
72 static __u32 hash_build0(const char *name, int namelen)
78 if (strncmp(name, ".", 1) == 0 && namelen == 1)
80 if (strncmp(name, "..", 2) == 0 && namelen == 2)
83 if (LVAR_HASH_PREFIX) {
85 strncpy((void *)&result,
86 name, min(namelen, (int)sizeof result));
88 struct ldiskfs_dx_hash_info hinfo;
91 hinfo.hash_version = LDISKFS_DX_HASH_TEA;
93 hinfo.hash_version = LDISKFS_DX_HASH_R5;
95 ldiskfsfs_dirhash(name, namelen, &hinfo);
97 if (LVAR_HASH_SANDWICH) {
100 hinfo.hash_version = LDISKFS_DX_HASH_TEA;
102 ldiskfsfs_dirhash(name, namelen, &hinfo);
103 result2 = hinfo.hash;
104 result = (0xfc000000 & result2) | (0x03ffffff & result);
112 HASH_GRAY_AREA = 1024
115 static __u32 hash_build(const char *name, int namelen)
119 hash = (hash_build0(name, namelen) << 1) & MAX_HASH_SIZE;
120 if (hash > MAX_HASH_SIZE - HASH_GRAY_AREA)
121 hash &= HASH_GRAY_AREA - 1;
125 static int mea_hash_segment(int count, const char *name, int namelen)
129 LASSERT(IS_PO2(MAX_HASH_SIZE + 1));
131 hash = hash_build(name, namelen) / (MAX_HASH_SIZE / count);
132 LASSERTF(hash < count, "hash %x count %d \n", hash, count);
137 static int mea_hash_segment(int count, char *name, int namelen)
139 #warning "fix for liblustre"
143 int raw_name2idx(int hashtype, int count, const char *name, int namelen)
147 LASSERT(namelen > 0);
152 case MEA_MAGIC_LAST_CHAR:
153 c = mea_last_char_hash(count, (char *)name, namelen);
155 case MEA_MAGIC_ALL_CHARS:
156 c = mea_all_chars_hash(count, (char *)name, namelen);
158 case MEA_MAGIC_HASH_SEGMENT:
159 c = mea_hash_segment(count, (char *)name, namelen);
162 CERROR("Unknown hash type 0x%x\n", hashtype);
169 int mea_name2idx(struct lmv_stripe_md *mea, const char *name, int namelen)
173 LASSERT(mea && mea->mea_count);
175 c = raw_name2idx(mea->mea_magic, mea->mea_count, name, namelen);
177 LASSERT(c < mea->mea_count);