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f2fs: add core directory operations
this adds core functions to find, add, delete, and link dentries. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
This commit is contained in:
Jaegeuk Kim
parent
57397d86c6
commit
6b4ea0160a
672
fs/f2fs/dir.c
Normal file
672
fs/f2fs/dir.c
Normal file
@ -0,0 +1,672 @@
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/**
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* fs/f2fs/dir.c
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*
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* Copyright (c) 2012 Samsung Electronics Co., Ltd.
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* http://www.samsung.com/
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/fs.h>
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#include <linux/f2fs_fs.h>
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#include "f2fs.h"
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#include "acl.h"
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static unsigned long dir_blocks(struct inode *inode)
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{
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return ((unsigned long long) (i_size_read(inode) + PAGE_CACHE_SIZE - 1))
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>> PAGE_CACHE_SHIFT;
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}
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static unsigned int dir_buckets(unsigned int level)
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{
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if (level < MAX_DIR_HASH_DEPTH / 2)
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return 1 << level;
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else
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return 1 << ((MAX_DIR_HASH_DEPTH / 2) - 1);
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}
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static unsigned int bucket_blocks(unsigned int level)
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{
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if (level < MAX_DIR_HASH_DEPTH / 2)
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return 2;
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else
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return 4;
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}
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static unsigned char f2fs_filetype_table[F2FS_FT_MAX] = {
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[F2FS_FT_UNKNOWN] = DT_UNKNOWN,
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[F2FS_FT_REG_FILE] = DT_REG,
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[F2FS_FT_DIR] = DT_DIR,
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[F2FS_FT_CHRDEV] = DT_CHR,
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[F2FS_FT_BLKDEV] = DT_BLK,
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[F2FS_FT_FIFO] = DT_FIFO,
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[F2FS_FT_SOCK] = DT_SOCK,
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[F2FS_FT_SYMLINK] = DT_LNK,
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};
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#define S_SHIFT 12
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static unsigned char f2fs_type_by_mode[S_IFMT >> S_SHIFT] = {
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[S_IFREG >> S_SHIFT] = F2FS_FT_REG_FILE,
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[S_IFDIR >> S_SHIFT] = F2FS_FT_DIR,
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[S_IFCHR >> S_SHIFT] = F2FS_FT_CHRDEV,
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[S_IFBLK >> S_SHIFT] = F2FS_FT_BLKDEV,
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[S_IFIFO >> S_SHIFT] = F2FS_FT_FIFO,
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[S_IFSOCK >> S_SHIFT] = F2FS_FT_SOCK,
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[S_IFLNK >> S_SHIFT] = F2FS_FT_SYMLINK,
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};
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static void set_de_type(struct f2fs_dir_entry *de, struct inode *inode)
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{
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mode_t mode = inode->i_mode;
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de->file_type = f2fs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
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}
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static unsigned long dir_block_index(unsigned int level, unsigned int idx)
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{
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unsigned long i;
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unsigned long bidx = 0;
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for (i = 0; i < level; i++)
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bidx += dir_buckets(i) * bucket_blocks(i);
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bidx += idx * bucket_blocks(level);
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return bidx;
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}
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static bool early_match_name(const char *name, int namelen,
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f2fs_hash_t namehash, struct f2fs_dir_entry *de)
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{
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if (le16_to_cpu(de->name_len) != namelen)
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return false;
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if (le32_to_cpu(de->hash_code) != namehash)
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return false;
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return true;
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}
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static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
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const char *name, int namelen, int *max_slots,
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f2fs_hash_t namehash, struct page **res_page)
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{
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struct f2fs_dir_entry *de;
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unsigned long bit_pos, end_pos, next_pos;
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struct f2fs_dentry_block *dentry_blk = kmap(dentry_page);
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int slots;
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bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
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NR_DENTRY_IN_BLOCK, 0);
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while (bit_pos < NR_DENTRY_IN_BLOCK) {
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de = &dentry_blk->dentry[bit_pos];
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slots = (le16_to_cpu(de->name_len) + F2FS_NAME_LEN - 1) /
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F2FS_NAME_LEN;
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if (early_match_name(name, namelen, namehash, de)) {
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if (!memcmp(dentry_blk->filename[bit_pos],
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name, namelen)) {
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*res_page = dentry_page;
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goto found;
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}
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}
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next_pos = bit_pos + slots;
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bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
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NR_DENTRY_IN_BLOCK, next_pos);
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if (bit_pos >= NR_DENTRY_IN_BLOCK)
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end_pos = NR_DENTRY_IN_BLOCK;
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else
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end_pos = bit_pos;
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if (*max_slots < end_pos - next_pos)
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*max_slots = end_pos - next_pos;
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}
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de = NULL;
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kunmap(dentry_page);
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found:
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return de;
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}
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static struct f2fs_dir_entry *find_in_level(struct inode *dir,
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unsigned int level, const char *name, int namelen,
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f2fs_hash_t namehash, struct page **res_page)
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{
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int s = (namelen + F2FS_NAME_LEN - 1) / F2FS_NAME_LEN;
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unsigned int nbucket, nblock;
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unsigned int bidx, end_block;
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struct page *dentry_page;
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struct f2fs_dir_entry *de = NULL;
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bool room = false;
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int max_slots = 0;
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BUG_ON(level > MAX_DIR_HASH_DEPTH);
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nbucket = dir_buckets(level);
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nblock = bucket_blocks(level);
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bidx = dir_block_index(level, namehash % nbucket);
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end_block = bidx + nblock;
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for (; bidx < end_block; bidx++) {
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/* no need to allocate new dentry pages to all the indices */
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dentry_page = find_data_page(dir, bidx);
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if (IS_ERR(dentry_page)) {
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room = true;
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continue;
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}
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de = find_in_block(dentry_page, name, namelen,
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&max_slots, namehash, res_page);
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if (de)
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break;
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if (max_slots >= s)
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room = true;
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f2fs_put_page(dentry_page, 0);
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}
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if (!de && room && F2FS_I(dir)->chash != namehash) {
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F2FS_I(dir)->chash = namehash;
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F2FS_I(dir)->clevel = level;
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}
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return de;
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}
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/*
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* Find an entry in the specified directory with the wanted name.
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* It returns the page where the entry was found (as a parameter - res_page),
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* and the entry itself. Page is returned mapped and unlocked.
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* Entry is guaranteed to be valid.
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*/
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struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
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struct qstr *child, struct page **res_page)
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{
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const char *name = child->name;
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int namelen = child->len;
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unsigned long npages = dir_blocks(dir);
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struct f2fs_dir_entry *de = NULL;
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f2fs_hash_t name_hash;
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unsigned int max_depth;
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unsigned int level;
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if (npages == 0)
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return NULL;
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*res_page = NULL;
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name_hash = f2fs_dentry_hash(name, namelen);
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max_depth = F2FS_I(dir)->i_current_depth;
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for (level = 0; level < max_depth; level++) {
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de = find_in_level(dir, level, name,
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namelen, name_hash, res_page);
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if (de)
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break;
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}
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if (!de && F2FS_I(dir)->chash != name_hash) {
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F2FS_I(dir)->chash = name_hash;
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F2FS_I(dir)->clevel = level - 1;
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}
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return de;
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}
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struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
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{
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struct page *page = NULL;
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struct f2fs_dir_entry *de = NULL;
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struct f2fs_dentry_block *dentry_blk = NULL;
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page = get_lock_data_page(dir, 0);
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if (IS_ERR(page))
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return NULL;
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dentry_blk = kmap(page);
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de = &dentry_blk->dentry[1];
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*p = page;
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unlock_page(page);
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return de;
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}
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ino_t f2fs_inode_by_name(struct inode *dir, struct qstr *qstr)
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{
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ino_t res = 0;
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struct f2fs_dir_entry *de;
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struct page *page;
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de = f2fs_find_entry(dir, qstr, &page);
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if (de) {
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res = le32_to_cpu(de->ino);
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kunmap(page);
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f2fs_put_page(page, 0);
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}
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return res;
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}
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void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
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struct page *page, struct inode *inode)
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{
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struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
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mutex_lock_op(sbi, DENTRY_OPS);
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lock_page(page);
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wait_on_page_writeback(page);
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de->ino = cpu_to_le32(inode->i_ino);
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set_de_type(de, inode);
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kunmap(page);
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set_page_dirty(page);
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dir->i_mtime = dir->i_ctime = CURRENT_TIME;
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mark_inode_dirty(dir);
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f2fs_put_page(page, 1);
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mutex_unlock_op(sbi, DENTRY_OPS);
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}
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void init_dent_inode(struct dentry *dentry, struct page *ipage)
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{
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struct inode *dir = dentry->d_parent->d_inode;
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struct f2fs_node *rn;
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if (IS_ERR(ipage))
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return;
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wait_on_page_writeback(ipage);
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/* copy dentry info. to this inode page */
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rn = (struct f2fs_node *)page_address(ipage);
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rn->i.i_pino = cpu_to_le32(dir->i_ino);
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rn->i.i_namelen = cpu_to_le32(dentry->d_name.len);
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memcpy(rn->i.i_name, dentry->d_name.name, dentry->d_name.len);
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set_page_dirty(ipage);
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}
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static int init_inode_metadata(struct inode *inode, struct dentry *dentry)
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{
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struct inode *dir = dentry->d_parent->d_inode;
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if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
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int err;
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err = new_inode_page(inode, dentry);
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if (err)
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return err;
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if (S_ISDIR(inode->i_mode)) {
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err = f2fs_make_empty(inode, dir);
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if (err) {
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remove_inode_page(inode);
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return err;
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}
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}
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err = f2fs_init_acl(inode, dir);
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if (err) {
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remove_inode_page(inode);
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return err;
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}
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} else {
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struct page *ipage;
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ipage = get_node_page(F2FS_SB(dir->i_sb), inode->i_ino);
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if (IS_ERR(ipage))
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return PTR_ERR(ipage);
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init_dent_inode(dentry, ipage);
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f2fs_put_page(ipage, 1);
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}
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if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK)) {
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inc_nlink(inode);
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f2fs_write_inode(inode, NULL);
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}
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return 0;
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}
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static void update_parent_metadata(struct inode *dir, struct inode *inode,
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unsigned int current_depth)
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{
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bool need_dir_update = false;
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if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
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if (S_ISDIR(inode->i_mode)) {
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inc_nlink(dir);
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need_dir_update = true;
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}
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clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);
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}
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dir->i_mtime = dir->i_ctime = CURRENT_TIME;
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if (F2FS_I(dir)->i_current_depth != current_depth) {
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F2FS_I(dir)->i_current_depth = current_depth;
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need_dir_update = true;
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}
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if (need_dir_update)
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f2fs_write_inode(dir, NULL);
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else
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mark_inode_dirty(dir);
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if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))
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clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
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}
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static int room_for_filename(struct f2fs_dentry_block *dentry_blk, int slots)
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{
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int bit_start = 0;
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int zero_start, zero_end;
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next:
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zero_start = find_next_zero_bit_le(&dentry_blk->dentry_bitmap,
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NR_DENTRY_IN_BLOCK,
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bit_start);
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if (zero_start >= NR_DENTRY_IN_BLOCK)
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return NR_DENTRY_IN_BLOCK;
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zero_end = find_next_bit_le(&dentry_blk->dentry_bitmap,
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NR_DENTRY_IN_BLOCK,
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zero_start);
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if (zero_end - zero_start >= slots)
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return zero_start;
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bit_start = zero_end + 1;
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if (zero_end + 1 >= NR_DENTRY_IN_BLOCK)
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return NR_DENTRY_IN_BLOCK;
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goto next;
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}
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int f2fs_add_link(struct dentry *dentry, struct inode *inode)
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{
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unsigned int bit_pos;
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unsigned int level;
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unsigned int current_depth;
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unsigned long bidx, block;
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f2fs_hash_t dentry_hash;
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struct f2fs_dir_entry *de;
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unsigned int nbucket, nblock;
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struct inode *dir = dentry->d_parent->d_inode;
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struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
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const char *name = dentry->d_name.name;
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int namelen = dentry->d_name.len;
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struct page *dentry_page = NULL;
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struct f2fs_dentry_block *dentry_blk = NULL;
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int slots = (namelen + F2FS_NAME_LEN - 1) / F2FS_NAME_LEN;
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int err = 0;
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int i;
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dentry_hash = f2fs_dentry_hash(name, dentry->d_name.len);
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level = 0;
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current_depth = F2FS_I(dir)->i_current_depth;
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if (F2FS_I(dir)->chash == dentry_hash) {
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level = F2FS_I(dir)->clevel;
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F2FS_I(dir)->chash = 0;
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}
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start:
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if (current_depth == MAX_DIR_HASH_DEPTH)
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return -ENOSPC;
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/* Increase the depth, if required */
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if (level == current_depth)
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++current_depth;
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nbucket = dir_buckets(level);
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nblock = bucket_blocks(level);
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bidx = dir_block_index(level, (dentry_hash % nbucket));
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for (block = bidx; block <= (bidx + nblock - 1); block++) {
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mutex_lock_op(sbi, DENTRY_OPS);
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dentry_page = get_new_data_page(dir, block, true);
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if (IS_ERR(dentry_page)) {
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mutex_unlock_op(sbi, DENTRY_OPS);
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return PTR_ERR(dentry_page);
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}
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dentry_blk = kmap(dentry_page);
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bit_pos = room_for_filename(dentry_blk, slots);
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if (bit_pos < NR_DENTRY_IN_BLOCK)
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goto add_dentry;
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kunmap(dentry_page);
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f2fs_put_page(dentry_page, 1);
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mutex_unlock_op(sbi, DENTRY_OPS);
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}
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/* Move to next level to find the empty slot for new dentry */
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++level;
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goto start;
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add_dentry:
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err = init_inode_metadata(inode, dentry);
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if (err)
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goto fail;
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wait_on_page_writeback(dentry_page);
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de = &dentry_blk->dentry[bit_pos];
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de->hash_code = cpu_to_le32(dentry_hash);
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de->name_len = cpu_to_le16(namelen);
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memcpy(dentry_blk->filename[bit_pos], name, namelen);
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de->ino = cpu_to_le32(inode->i_ino);
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set_de_type(de, inode);
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for (i = 0; i < slots; i++)
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test_and_set_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
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set_page_dirty(dentry_page);
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update_parent_metadata(dir, inode, current_depth);
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fail:
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kunmap(dentry_page);
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f2fs_put_page(dentry_page, 1);
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mutex_unlock_op(sbi, DENTRY_OPS);
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||||
return err;
|
||||
}
|
||||
|
||||
/**
|
||||
* It only removes the dentry from the dentry page,corresponding name
|
||||
* entry in name page does not need to be touched during deletion.
|
||||
*/
|
||||
void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
|
||||
struct inode *inode)
|
||||
{
|
||||
struct f2fs_dentry_block *dentry_blk;
|
||||
unsigned int bit_pos;
|
||||
struct address_space *mapping = page->mapping;
|
||||
struct inode *dir = mapping->host;
|
||||
struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
|
||||
int slots = (le16_to_cpu(dentry->name_len) + F2FS_NAME_LEN - 1) /
|
||||
F2FS_NAME_LEN;
|
||||
void *kaddr = page_address(page);
|
||||
int i;
|
||||
|
||||
mutex_lock_op(sbi, DENTRY_OPS);
|
||||
|
||||
lock_page(page);
|
||||
wait_on_page_writeback(page);
|
||||
|
||||
dentry_blk = (struct f2fs_dentry_block *)kaddr;
|
||||
bit_pos = dentry - (struct f2fs_dir_entry *)dentry_blk->dentry;
|
||||
for (i = 0; i < slots; i++)
|
||||
test_and_clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
|
||||
|
||||
/* Let's check and deallocate this dentry page */
|
||||
bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
|
||||
NR_DENTRY_IN_BLOCK,
|
||||
0);
|
||||
kunmap(page); /* kunmap - pair of f2fs_find_entry */
|
||||
set_page_dirty(page);
|
||||
|
||||
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
|
||||
|
||||
if (inode && S_ISDIR(inode->i_mode)) {
|
||||
drop_nlink(dir);
|
||||
f2fs_write_inode(dir, NULL);
|
||||
} else {
|
||||
mark_inode_dirty(dir);
|
||||
}
|
||||
|
||||
if (inode) {
|
||||
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
|
||||
drop_nlink(inode);
|
||||
if (S_ISDIR(inode->i_mode)) {
|
||||
drop_nlink(inode);
|
||||
i_size_write(inode, 0);
|
||||
}
|
||||
f2fs_write_inode(inode, NULL);
|
||||
if (inode->i_nlink == 0)
|
||||
add_orphan_inode(sbi, inode->i_ino);
|
||||
}
|
||||
|
||||
if (bit_pos == NR_DENTRY_IN_BLOCK) {
|
||||
loff_t page_offset;
|
||||
truncate_hole(dir, page->index, page->index + 1);
|
||||
clear_page_dirty_for_io(page);
|
||||
ClearPageUptodate(page);
|
||||
dec_page_count(sbi, F2FS_DIRTY_DENTS);
|
||||
inode_dec_dirty_dents(dir);
|
||||
page_offset = page->index << PAGE_CACHE_SHIFT;
|
||||
f2fs_put_page(page, 1);
|
||||
} else {
|
||||
f2fs_put_page(page, 1);
|
||||
}
|
||||
mutex_unlock_op(sbi, DENTRY_OPS);
|
||||
}
|
||||
|
||||
int f2fs_make_empty(struct inode *inode, struct inode *parent)
|
||||
{
|
||||
struct page *dentry_page;
|
||||
struct f2fs_dentry_block *dentry_blk;
|
||||
struct f2fs_dir_entry *de;
|
||||
void *kaddr;
|
||||
|
||||
dentry_page = get_new_data_page(inode, 0, true);
|
||||
if (IS_ERR(dentry_page))
|
||||
return PTR_ERR(dentry_page);
|
||||
|
||||
kaddr = kmap_atomic(dentry_page);
|
||||
dentry_blk = (struct f2fs_dentry_block *)kaddr;
|
||||
|
||||
de = &dentry_blk->dentry[0];
|
||||
de->name_len = cpu_to_le16(1);
|
||||
de->hash_code = 0;
|
||||
de->ino = cpu_to_le32(inode->i_ino);
|
||||
memcpy(dentry_blk->filename[0], ".", 1);
|
||||
set_de_type(de, inode);
|
||||
|
||||
de = &dentry_blk->dentry[1];
|
||||
de->hash_code = 0;
|
||||
de->name_len = cpu_to_le16(2);
|
||||
de->ino = cpu_to_le32(parent->i_ino);
|
||||
memcpy(dentry_blk->filename[1], "..", 2);
|
||||
set_de_type(de, inode);
|
||||
|
||||
test_and_set_bit_le(0, &dentry_blk->dentry_bitmap);
|
||||
test_and_set_bit_le(1, &dentry_blk->dentry_bitmap);
|
||||
kunmap_atomic(kaddr);
|
||||
|
||||
set_page_dirty(dentry_page);
|
||||
f2fs_put_page(dentry_page, 1);
|
||||
return 0;
|
||||
}
|
||||
|
||||
bool f2fs_empty_dir(struct inode *dir)
|
||||
{
|
||||
unsigned long bidx;
|
||||
struct page *dentry_page;
|
||||
unsigned int bit_pos;
|
||||
struct f2fs_dentry_block *dentry_blk;
|
||||
unsigned long nblock = dir_blocks(dir);
|
||||
|
||||
for (bidx = 0; bidx < nblock; bidx++) {
|
||||
void *kaddr;
|
||||
dentry_page = get_lock_data_page(dir, bidx);
|
||||
if (IS_ERR(dentry_page)) {
|
||||
if (PTR_ERR(dentry_page) == -ENOENT)
|
||||
continue;
|
||||
else
|
||||
return false;
|
||||
}
|
||||
|
||||
kaddr = kmap_atomic(dentry_page);
|
||||
dentry_blk = (struct f2fs_dentry_block *)kaddr;
|
||||
if (bidx == 0)
|
||||
bit_pos = 2;
|
||||
else
|
||||
bit_pos = 0;
|
||||
bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
|
||||
NR_DENTRY_IN_BLOCK,
|
||||
bit_pos);
|
||||
kunmap_atomic(kaddr);
|
||||
|
||||
f2fs_put_page(dentry_page, 1);
|
||||
|
||||
if (bit_pos < NR_DENTRY_IN_BLOCK)
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
static int f2fs_readdir(struct file *file, void *dirent, filldir_t filldir)
|
||||
{
|
||||
unsigned long pos = file->f_pos;
|
||||
struct inode *inode = file->f_dentry->d_inode;
|
||||
unsigned long npages = dir_blocks(inode);
|
||||
unsigned char *types = NULL;
|
||||
unsigned int bit_pos = 0, start_bit_pos = 0;
|
||||
int over = 0;
|
||||
struct f2fs_dentry_block *dentry_blk = NULL;
|
||||
struct f2fs_dir_entry *de = NULL;
|
||||
struct page *dentry_page = NULL;
|
||||
unsigned int n = 0;
|
||||
unsigned char d_type = DT_UNKNOWN;
|
||||
int slots;
|
||||
|
||||
types = f2fs_filetype_table;
|
||||
bit_pos = (pos % NR_DENTRY_IN_BLOCK);
|
||||
n = (pos / NR_DENTRY_IN_BLOCK);
|
||||
|
||||
for ( ; n < npages; n++) {
|
||||
dentry_page = get_lock_data_page(inode, n);
|
||||
if (IS_ERR(dentry_page))
|
||||
continue;
|
||||
|
||||
start_bit_pos = bit_pos;
|
||||
dentry_blk = kmap(dentry_page);
|
||||
while (bit_pos < NR_DENTRY_IN_BLOCK) {
|
||||
d_type = DT_UNKNOWN;
|
||||
bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
|
||||
NR_DENTRY_IN_BLOCK,
|
||||
bit_pos);
|
||||
if (bit_pos >= NR_DENTRY_IN_BLOCK)
|
||||
break;
|
||||
|
||||
de = &dentry_blk->dentry[bit_pos];
|
||||
if (types && de->file_type < F2FS_FT_MAX)
|
||||
d_type = types[de->file_type];
|
||||
|
||||
over = filldir(dirent,
|
||||
dentry_blk->filename[bit_pos],
|
||||
le16_to_cpu(de->name_len),
|
||||
(n * NR_DENTRY_IN_BLOCK) + bit_pos,
|
||||
le32_to_cpu(de->ino), d_type);
|
||||
if (over) {
|
||||
file->f_pos += bit_pos - start_bit_pos;
|
||||
goto success;
|
||||
}
|
||||
slots = (le16_to_cpu(de->name_len) + F2FS_NAME_LEN - 1)
|
||||
/ F2FS_NAME_LEN;
|
||||
bit_pos += slots;
|
||||
}
|
||||
bit_pos = 0;
|
||||
file->f_pos = (n + 1) * NR_DENTRY_IN_BLOCK;
|
||||
kunmap(dentry_page);
|
||||
f2fs_put_page(dentry_page, 1);
|
||||
dentry_page = NULL;
|
||||
}
|
||||
success:
|
||||
if (dentry_page && !IS_ERR(dentry_page)) {
|
||||
kunmap(dentry_page);
|
||||
f2fs_put_page(dentry_page, 1);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
const struct file_operations f2fs_dir_operations = {
|
||||
.llseek = generic_file_llseek,
|
||||
.read = generic_read_dir,
|
||||
.readdir = f2fs_readdir,
|
||||
.fsync = f2fs_sync_file,
|
||||
.unlocked_ioctl = f2fs_ioctl,
|
||||
};
|
||||
98
fs/f2fs/hash.c
Normal file
98
fs/f2fs/hash.c
Normal file
@ -0,0 +1,98 @@
|
||||
/**
|
||||
* 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
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License version 2 as
|
||||
* published by the Free Software Foundation.
|
||||
*/
|
||||
#include <linux/types.h>
|
||||
#include <linux/fs.h>
|
||||
#include <linux/f2fs_fs.h>
|
||||
#include <linux/cryptohash.h>
|
||||
#include <linux/pagemap.h>
|
||||
|
||||
#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 char *msg, int 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;
|
||||
}
|
||||
|
||||
f2fs_hash_t f2fs_dentry_hash(const char *name, int len)
|
||||
{
|
||||
__u32 hash, minor_hash;
|
||||
f2fs_hash_t f2fs_hash;
|
||||
const char *p;
|
||||
__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;
|
||||
|
||||
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];
|
||||
|
||||
f2fs_hash = hash;
|
||||
f2fs_hash &= ~F2FS_HASH_COL_BIT;
|
||||
return f2fs_hash;
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user