/*
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* This file is part of UBIFS.
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*
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* Copyright (C) 2006-2008 Nokia Corporation.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* Authors: Artem Bityutskiy (Битюцкий Артём)
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* Adrian Hunter
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*/
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/*
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* This header contains various key-related definitions and helper function.
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* UBIFS allows several key schemes, so we access key fields only via these
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* helpers. At the moment only one key scheme is supported.
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*
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* Simple key scheme
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* ~~~~~~~~~~~~~~~~~
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*
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* Keys are 64-bits long. First 32-bits are inode number (parent inode number
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* in case of direntry key). Next 3 bits are node type. The last 29 bits are
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* 4KiB offset in case of inode node, and direntry hash in case of a direntry
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* node. We use "r5" hash borrowed from reiserfs.
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*/
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#ifndef __UBIFS_KEY_H__
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#define __UBIFS_KEY_H__
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/**
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* key_mask_hash - mask a valid hash value.
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* @val: value to be masked
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*
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* We use hash values as offset in directories, so values %0 and %1 are
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* reserved for "." and "..". %2 is reserved for "end of readdir" marker. This
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* function makes sure the reserved values are not used.
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*/
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static inline uint32_t key_mask_hash(uint32_t hash)
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{
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hash &= UBIFS_S_KEY_HASH_MASK;
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if (unlikely(hash <= 2))
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hash += 3;
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return hash;
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}
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/**
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* key_r5_hash - R5 hash function (borrowed from reiserfs).
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* @s: direntry name
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* @len: name length
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*/
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static inline uint32_t key_r5_hash(const char *s, int len)
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{
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uint32_t a = 0;
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const signed char *str = (const signed char *)s;
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while (*str) {
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a += *str << 4;
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a += *str >> 4;
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a *= 11;
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str++;
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}
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return key_mask_hash(a);
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}
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/**
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* key_test_hash - testing hash function.
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* @str: direntry name
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* @len: name length
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*/
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static inline uint32_t key_test_hash(const char *str, int len)
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{
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uint32_t a = 0;
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len = min_t(uint32_t, len, 4);
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memcpy(&a, str, len);
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return key_mask_hash(a);
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}
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/**
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* ino_key_init - initialize inode key.
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* @c: UBIFS file-system description object
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* @key: key to initialize
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* @inum: inode number
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*/
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static inline void ino_key_init(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum)
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{
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key->u32[0] = inum;
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key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
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}
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/**
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* ino_key_init_flash - initialize on-flash inode key.
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* @c: UBIFS file-system description object
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* @k: key to initialize
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* @inum: inode number
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*/
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static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
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ino_t inum)
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{
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union ubifs_key *key = k;
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key->j32[0] = cpu_to_le32(inum);
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key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
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memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
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}
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/**
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* lowest_ino_key - get the lowest possible inode key.
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* @c: UBIFS file-system description object
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* @key: key to initialize
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* @inum: inode number
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*/
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static inline void lowest_ino_key(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum)
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{
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key->u32[0] = inum;
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key->u32[1] = 0;
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}
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/**
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* highest_ino_key - get the highest possible inode key.
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* @c: UBIFS file-system description object
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* @key: key to initialize
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* @inum: inode number
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*/
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static inline void highest_ino_key(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum)
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{
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key->u32[0] = inum;
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key->u32[1] = 0xffffffff;
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}
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/**
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* dent_key_init - initialize directory entry key.
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* @c: UBIFS file-system description object
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* @key: key to initialize
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* @inum: parent inode number
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* @nm: direntry name and length
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*/
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static inline void dent_key_init(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum,
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const struct qstr *nm)
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{
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uint32_t hash = c->key_hash(nm->name, nm->len);
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ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
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key->u32[0] = inum;
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key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
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}
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/**
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* dent_key_init_hash - initialize directory entry key without re-calculating
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* hash function.
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* @c: UBIFS file-system description object
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* @key: key to initialize
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* @inum: parent inode number
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* @hash: direntry name hash
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*/
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static inline void dent_key_init_hash(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum,
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uint32_t hash)
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{
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ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
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key->u32[0] = inum;
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key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
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}
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/**
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* dent_key_init_flash - initialize on-flash directory entry key.
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* @c: UBIFS file-system description object
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* @k: key to initialize
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* @inum: parent inode number
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* @nm: direntry name and length
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*/
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static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
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ino_t inum, const struct qstr *nm)
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{
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union ubifs_key *key = k;
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uint32_t hash = c->key_hash(nm->name, nm->len);
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ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
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key->j32[0] = cpu_to_le32(inum);
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key->j32[1] = cpu_to_le32(hash |
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(UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
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memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
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}
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/**
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* lowest_dent_key - get the lowest possible directory entry key.
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* @c: UBIFS file-system description object
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* @key: where to store the lowest key
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* @inum: parent inode number
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*/
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static inline void lowest_dent_key(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum)
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{
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key->u32[0] = inum;
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key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
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}
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/**
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* xent_key_init - initialize extended attribute entry key.
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* @c: UBIFS file-system description object
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* @key: key to initialize
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* @inum: host inode number
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* @nm: extended attribute entry name and length
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*/
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static inline void xent_key_init(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum,
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const struct qstr *nm)
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{
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uint32_t hash = c->key_hash(nm->name, nm->len);
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ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
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key->u32[0] = inum;
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key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
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}
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/**
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* xent_key_init_flash - initialize on-flash extended attribute entry key.
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* @c: UBIFS file-system description object
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* @k: key to initialize
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* @inum: host inode number
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* @nm: extended attribute entry name and length
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*/
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static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
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ino_t inum, const struct qstr *nm)
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{
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union ubifs_key *key = k;
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uint32_t hash = c->key_hash(nm->name, nm->len);
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ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
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key->j32[0] = cpu_to_le32(inum);
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key->j32[1] = cpu_to_le32(hash |
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(UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
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memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
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}
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/**
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* lowest_xent_key - get the lowest possible extended attribute entry key.
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* @c: UBIFS file-system description object
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* @key: where to store the lowest key
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* @inum: host inode number
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*/
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static inline void lowest_xent_key(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum)
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{
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key->u32[0] = inum;
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key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
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}
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/**
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* data_key_init - initialize data key.
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* @c: UBIFS file-system description object
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* @key: key to initialize
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* @inum: inode number
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* @block: block number
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*/
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static inline void data_key_init(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum,
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unsigned int block)
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{
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ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
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key->u32[0] = inum;
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key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
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}
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/**
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* highest_data_key - get the highest possible data key for an inode.
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* @c: UBIFS file-system description object
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* @key: key to initialize
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* @inum: inode number
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*/
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static inline void highest_data_key(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum)
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{
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data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
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}
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/**
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* trun_key_init - initialize truncation node key.
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* @c: UBIFS file-system description object
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* @key: key to initialize
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* @inum: inode number
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*
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* Note, UBIFS does not have truncation keys on the media and this function is
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* only used for purposes of replay.
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*/
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static inline void trun_key_init(const struct ubifs_info *c,
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union ubifs_key *key, ino_t inum)
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{
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key->u32[0] = inum;
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key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
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}
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/**
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* invalid_key_init - initialize invalid node key.
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* @c: UBIFS file-system description object
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* @key: key to initialize
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*
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* This is a helper function which marks a @key object as invalid.
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*/
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static inline void invalid_key_init(const struct ubifs_info *c,
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union ubifs_key *key)
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{
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key->u32[0] = 0xDEADBEAF;
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key->u32[1] = UBIFS_INVALID_KEY;
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}
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/**
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* key_type - get key type.
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* @c: UBIFS file-system description object
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* @key: key to get type of
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*/
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static inline int key_type(const struct ubifs_info *c,
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const union ubifs_key *key)
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{
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return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
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}
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/**
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* key_type_flash - get type of a on-flash formatted key.
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* @c: UBIFS file-system description object
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* @k: key to get type of
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*/
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static inline int key_type_flash(const struct ubifs_info *c, const void *k)
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{
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const union ubifs_key *key = k;
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return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
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}
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/**
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* key_inum - fetch inode number from key.
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* @c: UBIFS file-system description object
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* @k: key to fetch inode number from
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*/
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static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
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{
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const union ubifs_key *key = k;
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return key->u32[0];
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}
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/**
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* key_inum_flash - fetch inode number from an on-flash formatted key.
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* @c: UBIFS file-system description object
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* @k: key to fetch inode number from
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*/
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static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
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{
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const union ubifs_key *key = k;
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return le32_to_cpu(key->j32[0]);
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}
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/**
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* key_hash - get directory entry hash.
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* @c: UBIFS file-system description object
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* @key: the key to get hash from
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*/
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static inline uint32_t key_hash(const struct ubifs_info *c,
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const union ubifs_key *key)
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{
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return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
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}
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/**
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* key_hash_flash - get directory entry hash from an on-flash formatted key.
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* @c: UBIFS file-system description object
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* @k: the key to get hash from
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*/
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static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
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{
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const union ubifs_key *key = k;
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return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
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}
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/**
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* key_block - get data block number.
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* @c: UBIFS file-system description object
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* @key: the key to get the block number from
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*/
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static inline unsigned int key_block(const struct ubifs_info *c,
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const union ubifs_key *key)
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{
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return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
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}
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/**
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* key_block_flash - get data block number from an on-flash formatted key.
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* @c: UBIFS file-system description object
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* @k: the key to get the block number from
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*/
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static inline unsigned int key_block_flash(const struct ubifs_info *c,
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const void *k)
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{
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const union ubifs_key *key = k;
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return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
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}
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/**
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* key_read - transform a key to in-memory format.
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* @c: UBIFS file-system description object
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* @from: the key to transform
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* @to: the key to store the result
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*/
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static inline void key_read(const struct ubifs_info *c, const void *from,
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union ubifs_key *to)
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{
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const union ubifs_key *f = from;
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to->u32[0] = le32_to_cpu(f->j32[0]);
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to->u32[1] = le32_to_cpu(f->j32[1]);
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}
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/**
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* key_write - transform a key from in-memory format.
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* @c: UBIFS file-system description object
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* @from: the key to transform
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* @to: the key to store the result
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*/
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static inline void key_write(const struct ubifs_info *c,
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const union ubifs_key *from, void *to)
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{
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union ubifs_key *t = to;
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t->j32[0] = cpu_to_le32(from->u32[0]);
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t->j32[1] = cpu_to_le32(from->u32[1]);
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memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
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}
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/**
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* key_write_idx - transform a key from in-memory format for the index.
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* @c: UBIFS file-system description object
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* @from: the key to transform
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* @to: the key to store the result
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*/
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static inline void key_write_idx(const struct ubifs_info *c,
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const union ubifs_key *from, void *to)
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{
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union ubifs_key *t = to;
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t->j32[0] = cpu_to_le32(from->u32[0]);
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t->j32[1] = cpu_to_le32(from->u32[1]);
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}
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/**
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* key_copy - copy a key.
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* @c: UBIFS file-system description object
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* @from: the key to copy from
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* @to: the key to copy to
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*/
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static inline void key_copy(const struct ubifs_info *c,
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const union ubifs_key *from, union ubifs_key *to)
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{
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to->u64[0] = from->u64[0];
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}
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/**
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* keys_cmp - compare keys.
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* @c: UBIFS file-system description object
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* @key1: the first key to compare
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* @key2: the second key to compare
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*
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* This function compares 2 keys and returns %-1 if @key1 is less than
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* @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
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*/
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static inline int keys_cmp(const struct ubifs_info *c,
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const union ubifs_key *key1,
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const union ubifs_key *key2)
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{
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if (key1->u32[0] < key2->u32[0])
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return -1;
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if (key1->u32[0] > key2->u32[0])
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return 1;
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if (key1->u32[1] < key2->u32[1])
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return -1;
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if (key1->u32[1] > key2->u32[1])
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return 1;
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return 0;
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}
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/**
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* keys_eq - determine if keys are equivalent.
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* @c: UBIFS file-system description object
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* @key1: the first key to compare
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* @key2: the second key to compare
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*
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* This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
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* %0 if not.
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*/
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static inline int keys_eq(const struct ubifs_info *c,
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const union ubifs_key *key1,
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const union ubifs_key *key2)
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{
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if (key1->u32[0] != key2->u32[0])
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return 0;
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if (key1->u32[1] != key2->u32[1])
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return 0;
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return 1;
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}
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/**
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* is_hash_key - is a key vulnerable to hash collisions.
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* @c: UBIFS file-system description object
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* @key: key
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*
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* This function returns %1 if @key is a hashed key or %0 otherwise.
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*/
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static inline int is_hash_key(const struct ubifs_info *c,
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const union ubifs_key *key)
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{
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int type = key_type(c, key);
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return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
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}
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/**
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* key_max_inode_size - get maximum file size allowed by current key format.
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* @c: UBIFS file-system description object
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*/
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static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
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{
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switch (c->key_fmt) {
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case UBIFS_SIMPLE_KEY_FMT:
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return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
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default:
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return 0;
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}
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}
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#endif /* !__UBIFS_KEY_H__ */
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