From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/f2fs/hash.c | 137 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 137 insertions(+) create mode 100644 fs/f2fs/hash.c (limited to 'fs/f2fs/hash.c') diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c new file mode 100644 index 000000000..049ce50ce --- /dev/null +++ b/fs/f2fs/hash.c @@ -0,0 +1,137 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/f2fs/hash.c + * + * Copyright (c) 2012 Samsung Electronics Co., Ltd. + * http://www.samsung.com/ + * + * Portions of this code from linux/fs/ext3/hash.c + * + * Copyright (C) 2002 by Theodore Ts'o + */ +#include +#include +#include +#include +#include + +#include "f2fs.h" + +/* + * Hashing code copied from ext3 + */ +#define DELTA 0x9E3779B9 + +static void TEA_transform(unsigned int buf[4], unsigned int 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 unsigned char *msg, size_t len, + unsigned int *buf, int num) +{ + unsigned 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; +} + +static u32 TEA_hash_name(const u8 *p, size_t len) +{ + __u32 in[8], buf[4]; + + /* Initialize the default seed for the hash checksum functions */ + buf[0] = 0x67452301; + buf[1] = 0xefcdab89; + buf[2] = 0x98badcfe; + buf[3] = 0x10325476; + + while (1) { + str2hashbuf(p, len, in, 4); + TEA_transform(buf, in); + p += 16; + if (len <= 16) + break; + len -= 16; + } + return buf[0] & ~F2FS_HASH_COL_BIT; +} + +/* + * Compute @fname->hash. For all directories, @fname->disk_name must be set. + * For casefolded directories, @fname->usr_fname must be set, and also + * @fname->cf_name if the filename is valid Unicode and is not "." or "..". + */ +void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname) +{ + const u8 *name = fname->disk_name.name; + size_t len = fname->disk_name.len; + + WARN_ON_ONCE(!name); + + if (is_dot_dotdot(name, len)) { + fname->hash = 0; + return; + } + +#if IS_ENABLED(CONFIG_UNICODE) + if (IS_CASEFOLDED(dir)) { + /* + * If the casefolded name is provided, hash it instead of the + * on-disk name. If the casefolded name is *not* provided, that + * should only be because the name wasn't valid Unicode or was + * "." or "..", so fall back to treating the name as an opaque + * byte sequence. Note that to handle encrypted directories, + * the fallback must use usr_fname (plaintext) rather than + * disk_name (ciphertext). + */ + WARN_ON_ONCE(!fname->usr_fname->name); + if (fname->cf_name.name) { + name = fname->cf_name.name; + len = fname->cf_name.len; + } else { + name = fname->usr_fname->name; + len = fname->usr_fname->len; + } + if (IS_ENCRYPTED(dir)) { + struct qstr tmp = QSTR_INIT(name, len); + + fname->hash = + cpu_to_le32(fscrypt_fname_siphash(dir, &tmp)); + return; + } + } +#endif + fname->hash = cpu_to_le32(TEA_hash_name(name, len)); +} -- cgit v1.2.3