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authorDavid Woodhouse <David.Woodhouse@intel.com>2008-08-19 19:21:57 +0100
committerChris Mason <chris.mason@oracle.com>2008-09-25 11:04:06 -0400
commit615f996fb8185a0bc02812ebd72cb77ded5645f1 (patch)
tree0e97c4fd52b44d603e589e41c90892739e6f5a30 /fs/btrfs
parent76fcef19c40328499a2f6d59d76b72fd03d2cc82 (diff)
Switch btrfs_name_hash() to crc32c
Date: Tue, 19 Aug 2008 19:21:57 +0100 Using a 64-bit hash as the readdir cookie is just asking for trouble. And gets it, when we try to export the file system by NFS. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/Makefile2
-rw-r--r--fs/btrfs/hash.c112
-rw-r--r--fs/btrfs/hash.h7
3 files changed, 7 insertions, 114 deletions
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index 75f8818cbfe..8213bba1de9 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -3,7 +3,7 @@ ifneq ($(KERNELRELEASE),)
obj-m := btrfs.o
btrfs-y := super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
- hash.o file-item.o inode-item.o inode-map.o disk-io.o \
+ file-item.o inode-item.o inode-map.o disk-io.o \
transaction.o bit-radix.o inode.o file.o tree-defrag.o \
extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \
extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \
diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c
deleted file mode 100644
index 21037cfca9b..00000000000
--- a/fs/btrfs/hash.c
+++ /dev/null
@@ -1,112 +0,0 @@
-/*
- * Copyright (C) 2007 Oracle. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License v2 as published by the Free Software Foundation.
- *
- * 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 for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 021110-1307, USA.
- */
-
-/*
- * Original copy from:
- * linux/fs/ext3/hash.c
- *
- * Copyright (C) 2002 by Theodore Ts'o
- *
- * This file is released under the GPL v2.
- *
- * This file may be redistributed under the terms of the GNU Public
- * License.
- */
-
-#include <linux/types.h>
-#include "hash.h"
-#define DELTA 0x9E3779B9
-
-static void TEA_transform(__u32 buf[2], __u32 const in[])
-{
- __u32 sum = 0;
- __u32 b0 = buf[0], b1 = buf[1];
- __u32 a = in[0], b = in[1], c = in[2], d = in[3];
- int n = 16;
-
- do {
- sum += DELTA;
- b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
- b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
- } while(--n);
-
- buf[0] += b0;
- buf[1] += b1;
-}
-
-static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
-{
- __u32 pad, val;
- int i;
-
- pad = (__u32)len | ((__u32)len << 8);
- pad |= pad << 16;
-
- val = pad;
- if (len > num*4)
- len = num * 4;
- for (i=0; i < len; i++) {
- if ((i % 4) == 0)
- val = pad;
- val = msg[i] + (val << 8);
- if ((i % 4) == 3) {
- *buf++ = val;
- val = pad;
- num--;
- }
- }
- if (--num >= 0)
- *buf++ = val;
- while (--num >= 0)
- *buf++ = pad;
-}
-
-u64 btrfs_name_hash(const char *name, int len)
-{
- __u32 hash;
- __u32 minor_hash = 0;
- const char *p;
- __u32 in[8], buf[4];
- u64 hash_result;
-
- if (len == 1 && *name == '.') {
- return 1;
- } else if (len == 2 && name[0] == '.' && name[1] == '.') {
- return 2;
- }
-
- /* Initialize the default seed for the hash checksum functions */
- buf[0] = 0x67452301;
- buf[1] = 0xefcdab89;
- buf[2] = 0x98badcfe;
- buf[3] = 0x10325476;
-
- p = name;
- while (len > 0) {
- str2hashbuf(p, len, in, 4);
- TEA_transform(buf, in);
- len -= 16;
- p += 16;
- }
- hash = buf[0];
- minor_hash = buf[1];
- hash_result = buf[0];
- hash_result <<= 32;
- hash_result |= buf[1];
- return hash_result;
-}
diff --git a/fs/btrfs/hash.h b/fs/btrfs/hash.h
index 868ee17ca77..2a020b27676 100644
--- a/fs/btrfs/hash.h
+++ b/fs/btrfs/hash.h
@@ -18,5 +18,10 @@
#ifndef __HASH__
#define __HASH__
-u64 btrfs_name_hash(const char *name, int len);
+
+#include "crc32c.h"
+static inline u64 btrfs_name_hash(const char *name, int len)
+{
+ return btrfs_crc32c((u32)~1, name, len);
+}
#endif