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>
38 static int mea_last_char_hash(int count, char *name, int namelen)
42 c = name[namelen - 1];
44 CWARN("looks like wrong len is passed\n");
49 static int mea_all_chars_hash(int count, char *name, int namelen)
53 while (--namelen >= 0)
59 /* This hash calculate method must be same as the lvar hash method */
60 static int mea_hash_segment(int count, char *name, int namelen)
63 __u32 hash_segment = MAX_HASH_SIZE / count;
65 strncpy((void *)&result, name, min(namelen, (int)sizeof result));
67 result = (result << 1) & 0x7fffffff;
69 return result / hash_segment;
72 int raw_name2idx(int hashtype, int count, const char *name, int namelen)
81 case MEA_MAGIC_LAST_CHAR:
82 c = mea_last_char_hash(count, (char *) name, namelen);
84 case MEA_MAGIC_ALL_CHARS:
85 c = mea_all_chars_hash(count, (char *) name, namelen);
87 case MEA_MAGIC_HASH_SEGMENT:
88 c = mea_hash_segment(count, (char *) name, namelen);
91 CERROR("unknown hash type 0x%x\n", hashtype);
97 int mea_name2idx(struct lmv_stripe_md *mea, char *name, int namelen)
101 LASSERT(mea && mea->mea_count);
103 c = raw_name2idx(mea->mea_magic, mea->mea_count, name, namelen);
105 LASSERT(c < mea->mea_count);