From 615f996fb8185a0bc02812ebd72cb77ded5645f1 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Tue, 19 Aug 2008 19:21:57 +0100 Subject: [PATCH] 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 Signed-off-by: Chris Mason --- fs/btrfs/Makefile | 2 +- fs/btrfs/hash.c | 112 ---------------------------------------------- fs/btrfs/hash.h | 7 ++- 3 files changed, 7 insertions(+), 114 deletions(-) delete mode 100644 fs/btrfs/hash.c diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile index 75f8818cbfee..8213bba1de9f 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 21037cfca9bd..000000000000 --- 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 -#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 868ee17ca77a..2a020b276768 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