ref: 34dd7330431c99292c332c724e0e493b08e40bd6
dir: /lwext4/ext4_dir_idx.c/
/*
* Copyright (c) 2013 Grzegorz Kostka ([email protected])
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup lwext4
* @{
*/
/**
* @file ext4_dir_idx.c
* @brief Directory indexing procedures.
*/
#include <ext4_config.h>
#include <ext4_dir_idx.h>
#include <ext4_dir.h>
#include <ext4_blockdev.h>
#include <ext4_fs.h>
#include <ext4_super.h>
#include <ext4_hash.h>
#include <string.h>
#include <stdlib.h>
/**@brief Sort entry item.*/
struct ext4_dx_sort_entry {
uint32_t hash;
uint32_t rec_len;
void *dentry;
};
static int ext4_dir_dx_hash_string(struct ext4_hash_info *hinfo, int len,
const char *name)
{
return ext2_htree_hash(name, len, hinfo->seed, hinfo->hash_version,
&hinfo->hash, &hinfo->minor_hash);
}
uint8_t ext4_dir_dx_root_info_get_hash_version(
struct ext4_directory_dx_root_info *root_info)
{
return root_info->hash_version;
}
void ext4_dir_dx_root_info_set_hash_version(
struct ext4_directory_dx_root_info *root_info, uint8_t v)
{
root_info->hash_version = v;
}
uint8_t ext4_dir_dx_root_info_get_info_length(
struct ext4_directory_dx_root_info *root_info)
{
return root_info->info_length;
}
void ext4_dir_dx_root_info_set_info_length(
struct ext4_directory_dx_root_info *root_info, uint8_t len)
{
root_info->info_length = len;
}
uint8_t ext4_dir_dx_root_info_get_indirect_levels(
struct ext4_directory_dx_root_info *root_info)
{
return root_info->indirect_levels;
}
void ext4_dir_dx_root_info_set_indirect_levels(
struct ext4_directory_dx_root_info *root_info, uint8_t lvl)
{
root_info->indirect_levels = lvl;
}
uint16_t ext4_dir_dx_countlimit_get_limit(
struct ext4_directory_dx_countlimit *climit)
{
return to_le16(climit->limit);
}
void ext4_dir_dx_countlimit_set_limit(
struct ext4_directory_dx_countlimit *climit, uint16_t limit)
{
climit->limit = to_le16(limit);
}
uint16_t ext4_dir_dx_countlimit_get_count(
struct ext4_directory_dx_countlimit *climit)
{
return to_le16(climit->count);
}
void ext4_dir_dx_countlimit_set_count(
struct ext4_directory_dx_countlimit *climit, uint16_t count)
{
climit->count = to_le16(count);
}
uint32_t ext4_dir_dx_entry_get_hash(
struct ext4_directory_dx_entry *entry)
{
return to_le32(entry->hash);
}
void ext4_dir_dx_entry_set_hash(
struct ext4_directory_dx_entry *entry, uint32_t hash)
{
entry->hash = to_le32(hash);
}
uint32_t ext4_dir_dx_entry_get_block(
struct ext4_directory_dx_entry *entry)
{
return to_le32(entry->block);
}
void ext4_dir_dx_entry_set_block(
struct ext4_directory_dx_entry *entry, uint32_t block)
{
entry->block = to_le32(block);
}
/****************************************************************************/
int ext4_dir_dx_init(struct ext4_inode_ref *dir)
{
/* Load block 0, where will be index root located */
uint32_t fblock;
int rc = ext4_fs_get_inode_data_block_index(dir, 0,
&fblock);
if (rc != EOK)
return rc;
struct ext4_block block;
rc = ext4_block_get(dir->fs->bdev, &block, fblock);
if (rc != EOK)
return rc;
/* Initialize pointers to data structures */
struct ext4_directory_dx_root *root = (void *)block.data;
struct ext4_directory_dx_root_info *info = &(root->info);
/* Initialize root info structure */
uint8_t hash_version = ext4_get8(&dir->fs->sb, default_hash_version);
ext4_dir_dx_root_info_set_hash_version(info, hash_version);
ext4_dir_dx_root_info_set_indirect_levels(info, 0);
ext4_dir_dx_root_info_set_info_length(info, 8);
/* Set limit and current number of entries */
struct ext4_directory_dx_countlimit *countlimit =
(struct ext4_directory_dx_countlimit *) &root->entries;
ext4_dir_dx_countlimit_set_count(countlimit, 1);
uint32_t block_size =
ext4_sb_get_block_size(&dir->fs->sb);
uint32_t entry_space =
block_size - 2 * sizeof(struct ext4_directory_dx_dot_entry) -
sizeof(struct ext4_directory_dx_root_info);
uint16_t root_limit = entry_space / sizeof(struct ext4_directory_dx_entry);
ext4_dir_dx_countlimit_set_limit(countlimit, root_limit);
/* Append new block, where will be new entries inserted in the future */
uint32_t iblock;
rc = ext4_fs_append_inode_block(dir, &fblock, &iblock);
if (rc != EOK) {
ext4_block_set(dir->fs->bdev, &block);
return rc;
}
struct ext4_block new_block;
rc = ext4_block_get(dir->fs->bdev, &new_block, fblock);
if (rc != EOK) {
ext4_block_set(dir->fs->bdev, &block);
return rc;
}
/* Fill the whole block with empty entry */
struct ext4_directory_entry_ll *block_entry = (void *)new_block.data;
ext4_dir_entry_ll_set_entry_length(block_entry, block_size);
ext4_dir_entry_ll_set_inode(block_entry, 0);
new_block.dirty = true;
rc = ext4_block_set(dir->fs->bdev, &new_block);
if (rc != EOK) {
ext4_block_set(dir->fs->bdev, &block);
return rc;
}
/* Connect new block to the only entry in index */
struct ext4_directory_dx_entry *entry = root->entries;
ext4_dir_dx_entry_set_block(entry, iblock);
block.dirty = true;
return ext4_block_set(dir->fs->bdev, &block);
}
/**@brief Initialize hash info structure necessary for index operations.
* @param hinfo Pointer to hinfo to be initialized
* @param root_block Root block (number 0) of index
* @param sb Pointer to superblock
* @param name_len Length of name to be computed hash value from
* @param name Name to be computed hash value from
* @return Standard error code
*/
static int ext4_dir_hinfo_init(struct ext4_hash_info *hinfo,
struct ext4_block *root_block, struct ext4_sblock *sb, size_t name_len,
const char *name)
{
struct ext4_directory_dx_root *root =
(struct ext4_directory_dx_root *) root_block->data;
if ((root->info.hash_version != EXT2_HTREE_LEGACY) &&
(root->info.hash_version != EXT2_HTREE_HALF_MD4) &&
(root->info.hash_version != EXT2_HTREE_TEA))
return EXT4_ERR_BAD_DX_DIR;
/* Check unused flags */
if (root->info.unused_flags != 0)
return EXT4_ERR_BAD_DX_DIR;
/* Check indirect levels */
if (root->info.indirect_levels > 1)
return EXT4_ERR_BAD_DX_DIR;
/* Check if node limit is correct */
uint32_t block_size = ext4_sb_get_block_size(sb);
uint32_t entry_space = block_size;
entry_space -= 2 * sizeof(struct ext4_directory_dx_dot_entry);
entry_space -= sizeof(struct ext4_directory_dx_root_info);
entry_space = entry_space / sizeof(struct ext4_directory_dx_entry);
uint16_t limit = ext4_dir_dx_countlimit_get_limit(
(struct ext4_directory_dx_countlimit *) &root->entries);
if (limit != entry_space)
return EXT4_ERR_BAD_DX_DIR;
/* Check hash version and modify if necessary */
hinfo->hash_version =
ext4_dir_dx_root_info_get_hash_version(&root->info);
if ((hinfo->hash_version <= EXT2_HTREE_TEA) &&
(ext4_sb_check_flag(sb, EXT4_SUPERBLOCK_FLAGS_UNSIGNED_HASH))) {
/* Use unsigned hash */
hinfo->hash_version += 3;
}
/* Load hash seed from superblock */
hinfo->seed = ext4_get8(sb, hash_seed);
/* Compute hash value of name */
if (name)
return ext4_dir_dx_hash_string(hinfo, name_len, name);
return EOK;
}
/**@brief Walk through index tree and load leaf with corresponding hash value.
* @param hinfo Initialized hash info structure
* @param inode_ref Current i-node
* @param root_block Root block (iblock 0), where is root node located
* @param dx_block Pointer to leaf node in dx_blocks array
* @param dx_blocks Array with the whole path from root to leaf
* @return Standard error code
*/
static int ext4_dir_dx_get_leaf(struct ext4_hash_info *hinfo,
struct ext4_inode_ref *inode_ref, struct ext4_block *root_block,
struct ext4_directory_dx_block **dx_block,
struct ext4_directory_dx_block *dx_blocks)
{
struct ext4_directory_dx_block *tmp_dx_block = dx_blocks;
struct ext4_directory_dx_root *root =
(struct ext4_directory_dx_root *) root_block->data;
struct ext4_directory_dx_entry *entries =
(struct ext4_directory_dx_entry *) &root->entries;
uint16_t limit = ext4_dir_dx_countlimit_get_limit(
(struct ext4_directory_dx_countlimit *) entries);
uint8_t indirect_level =
ext4_dir_dx_root_info_get_indirect_levels(&root->info);
struct ext4_block *tmp_block = root_block;
struct ext4_directory_dx_entry *p;
struct ext4_directory_dx_entry *q;
struct ext4_directory_dx_entry *m;
struct ext4_directory_dx_entry *at;
/* Walk through the index tree */
while (true) {
uint16_t count = ext4_dir_dx_countlimit_get_count(
(struct ext4_directory_dx_countlimit *) entries);
if ((count == 0) || (count > limit))
return EXT4_ERR_BAD_DX_DIR;
/* Do binary search in every node */
p = entries + 1;
q = entries + count - 1;
while (p <= q) {
m = p + (q - p) / 2;
if (ext4_dir_dx_entry_get_hash(m) > hinfo->hash)
q = m - 1;
else
p = m + 1;
}
at = p - 1;
/* Write results */
memcpy(&tmp_dx_block->block, tmp_block, sizeof(struct ext4_block));
tmp_dx_block->entries = entries;
tmp_dx_block->position = at;
/* Is algorithm in the leaf? */
if (indirect_level == 0) {
*dx_block = tmp_dx_block;
return EOK;
}
/* Goto child node */
uint32_t next_block = ext4_dir_dx_entry_get_block(at);
indirect_level--;
uint32_t fblock;
int rc = ext4_fs_get_inode_data_block_index(inode_ref,
next_block, &fblock);
if (rc != EOK)
return rc;
rc = ext4_block_get(inode_ref->fs->bdev, tmp_block, fblock);
if (rc != EOK)
return rc;
entries = ((struct ext4_directory_dx_node *) tmp_block->data)->entries;
limit = ext4_dir_dx_countlimit_get_limit(
(struct ext4_directory_dx_countlimit *) entries);
uint16_t entry_space =
ext4_sb_get_block_size(&inode_ref->fs->sb) -
sizeof(struct ext4_fake_directory_entry);
entry_space = entry_space / sizeof(struct ext4_directory_dx_entry);
if (limit != entry_space) {
ext4_block_set(inode_ref->fs->bdev, tmp_block);
return EXT4_ERR_BAD_DX_DIR;
}
++tmp_dx_block;
}
/* Unreachable */
return EOK;
}
/**@brief Check if the the next block would be checked during entry search.
* @param inode_ref Directory i-node
* @param hash Hash value to check
* @param dx_block Current block
* @param dx_blocks Array with path from root to leaf node
* @return Standard Error codee
*/
static int ext4_dir_dx_next_block(struct ext4_inode_ref *inode_ref,
uint32_t hash, struct ext4_directory_dx_block *dx_block,
struct ext4_directory_dx_block *dx_blocks)
{
uint32_t num_handles = 0;
struct ext4_directory_dx_block *p = dx_block;
/* Try to find data block with next bunch of entries */
while (true) {
p->position++;
uint16_t count = ext4_dir_dx_countlimit_get_count(
(struct ext4_directory_dx_countlimit *) p->entries);
if (p->position < p->entries + count)
break;
if (p == dx_blocks)
return EOK;
num_handles++;
p--;
}
/* Check hash collision (if not occured - no next block cannot be used)*/
uint32_t current_hash = ext4_dir_dx_entry_get_hash(p->position);
if ((hash & 1) == 0) {
if ((current_hash & ~1) != hash)
return 0;
}
/* Fill new path */
while (num_handles--) {
uint32_t block_idx =
ext4_dir_dx_entry_get_block(p->position);
uint32_t block_addr;
int rc = ext4_fs_get_inode_data_block_index(inode_ref,
block_idx, &block_addr);
if (rc != EOK)
return rc;
struct ext4_block block;
rc = ext4_block_get(inode_ref->fs->bdev, &block, block_addr);
if (rc != EOK)
return rc;
p++;
/* Don't forget to put old block (prevent memory leak) */
ext4_block_set(inode_ref->fs->bdev, &p->block);
memcpy(&p->block, &p->block, sizeof(block));
p->entries = ((struct ext4_directory_dx_node *) block.data)->entries;
p->position = p->entries;
}
return ENOENT;
}
int ext4_dir_dx_find_entry(struct ext4_directory_search_result * result,
struct ext4_inode_ref *inode_ref, size_t name_len, const char *name)
{
/* Load direct block 0 (index root) */
uint32_t root_block_addr;
int rc = ext4_fs_get_inode_data_block_index(inode_ref, 0,
&root_block_addr);
if (rc != EOK)
return rc;
struct ext4_fs *fs = inode_ref->fs;
struct ext4_block root_block;
rc = ext4_block_get(fs->bdev, &root_block, root_block_addr);
if (rc != EOK)
return rc;
/* Initialize hash info (compute hash value) */
struct ext4_hash_info hinfo;
rc = ext4_dir_hinfo_init(&hinfo, &root_block, &fs->sb,
name_len, name);
if (rc != EOK) {
ext4_block_set(fs->bdev, &root_block);
return EXT4_ERR_BAD_DX_DIR;
}
/*
* Hardcoded number 2 means maximum height of index tree,
* specified in the Linux driver.
*/
struct ext4_directory_dx_block dx_blocks[2];
struct ext4_directory_dx_block *dx_block;
struct ext4_directory_dx_block *tmp;
rc = ext4_dir_dx_get_leaf(&hinfo, inode_ref, &root_block,
&dx_block, dx_blocks);
if (rc != EOK) {
ext4_block_set(fs->bdev, &root_block);
return EXT4_ERR_BAD_DX_DIR;
}
do {
/* Load leaf block */
uint32_t leaf_block_idx =
ext4_dir_dx_entry_get_block(dx_block->position);
uint32_t leaf_block_addr;
rc = ext4_fs_get_inode_data_block_index(inode_ref,
leaf_block_idx, &leaf_block_addr);
if (rc != EOK)
goto cleanup;
struct ext4_block leaf_block;
rc = ext4_block_get(fs->bdev, &leaf_block, leaf_block_addr);
if (rc != EOK)
goto cleanup;
/* Linear search inside block */
struct ext4_directory_entry_ll *res_dentry;
rc = ext4_dir_find_in_block(&leaf_block, &fs->sb,
name_len, name, &res_dentry);
/* Found => return it */
if (rc == EOK) {
result->block = leaf_block;
result->dentry = res_dentry;
goto cleanup;
}
/* Not found, leave untouched */
ext4_block_set(fs->bdev, &leaf_block);
if (rc != ENOENT)
goto cleanup;
/* check if the next block could be checked */
rc = ext4_dir_dx_next_block(inode_ref, hinfo.hash,
dx_block, &dx_blocks[0]);
if (rc < 0)
goto cleanup;
} while (rc == ENOENT);
/* Entry not found */
rc = ENOENT;
cleanup:
/* The whole path must be released (preventing memory leak) */
tmp = dx_blocks;
while (tmp <= dx_block) {
ext4_block_set(fs->bdev, &tmp->block);
++tmp;
}
return rc;
}
/**@brief Compare function used to pass in quicksort implementation.
* It can compare two entries by hash value.
* @param arg1 First entry
* @param arg2 Second entry
* @param dummy Unused parameter, can be NULL
*
* @return Classic compare result
* (0: equal, -1: arg1 < arg2, 1: arg1 > arg2)
*/
static int ext4_dir_dx_entry_comparator(const void *arg1, const void *arg2)
{
struct ext4_dx_sort_entry *entry1 = (void *)arg1;
struct ext4_dx_sort_entry *entry2 = (void *)arg2;
if (entry1->hash == entry2->hash)
return 0;
if (entry1->hash < entry2->hash)
return -1;
else
return 1;
}
/**@brief Insert new index entry to block.
* Note that space for new entry must be checked by caller.
* @param index_block Block where to insert new entry
* @param hash Hash value covered by child node
* @param iblock Logical number of child block
*
*/
static void ext4_dir_dx_insert_entry(
struct ext4_directory_dx_block *index_block, uint32_t hash,
uint32_t iblock)
{
struct ext4_directory_dx_entry *old_index_entry = index_block->position;
struct ext4_directory_dx_entry *new_index_entry = old_index_entry + 1;
struct ext4_directory_dx_countlimit *countlimit =
(struct ext4_directory_dx_countlimit *) index_block->entries;
uint32_t count = ext4_dir_dx_countlimit_get_count(countlimit);
struct ext4_directory_dx_entry *start_index = index_block->entries;
size_t bytes = (void *) (start_index + count) - (void *) (new_index_entry);
memmove(new_index_entry + 1, new_index_entry, bytes);
ext4_dir_dx_entry_set_block(new_index_entry, iblock);
ext4_dir_dx_entry_set_hash(new_index_entry, hash);
ext4_dir_dx_countlimit_set_count(countlimit, count + 1);
index_block->block.dirty = true;
}
/**@brief Split directory entries to two parts preventing node overflow.
* @param inode_ref Directory i-node
* @param hinfo Hash info
* @param old_data_block Block with data to be split
* @param index_block Block where index entries are located
* @param new_data_block Output value for newly allocated data block
*/
static int ext4_dir_dx_split_data(struct ext4_inode_ref *inode_ref,
struct ext4_hash_info *hinfo, struct ext4_block *old_data_block,
struct ext4_directory_dx_block *index_block,
struct ext4_block *new_data_block)
{
int rc = EOK;
/* Allocate buffer for directory entries */
uint32_t block_size =
ext4_sb_get_block_size(&inode_ref->fs->sb);
void *entry_buffer = malloc(block_size);
if (entry_buffer == NULL)
return ENOMEM;
/* dot entry has the smallest size available */
uint32_t max_entry_count =
block_size / sizeof(struct ext4_directory_dx_dot_entry);
/* Allocate sort entry */
struct ext4_dx_sort_entry *sort_array =
malloc(max_entry_count * sizeof(struct ext4_dx_sort_entry));
if (sort_array == NULL) {
free(entry_buffer);
return ENOMEM;
}
uint32_t idx = 0;
uint32_t real_size = 0;
/* Initialize hinfo */
struct ext4_hash_info tmp_hinfo;
memcpy(&tmp_hinfo, hinfo, sizeof(struct ext4_hash_info));
/* Load all valid entries to the buffer */
struct ext4_directory_entry_ll *dentry = (void *)old_data_block->data;
void *entry_buffer_ptr = entry_buffer;
while ((void *)dentry < (void *)(old_data_block->data + block_size)) {
/* Read only valid entries */
if (ext4_dir_entry_ll_get_inode(dentry) && dentry->name_length) {
uint8_t len = ext4_dir_entry_ll_get_name_length(
&inode_ref->fs->sb, dentry);
rc = ext4_dir_dx_hash_string(&tmp_hinfo, len, (char*)dentry->name);
if(rc != EOK) {
free(sort_array);
free(entry_buffer);
return rc;
}
uint32_t rec_len = 8 + len;
if ((rec_len % 4) != 0)
rec_len += 4 - (rec_len % 4);
memcpy(entry_buffer_ptr, dentry, rec_len);
sort_array[idx].dentry = entry_buffer_ptr;
sort_array[idx].rec_len = rec_len;
sort_array[idx].hash = tmp_hinfo.hash;
entry_buffer_ptr += rec_len;
real_size += rec_len;
idx++;
}
dentry = (void *) dentry +
ext4_dir_entry_ll_get_entry_length(dentry);
}
/* Sort all entries */
qsort(sort_array, idx, sizeof(struct ext4_dx_sort_entry),
ext4_dir_dx_entry_comparator);
/* Allocate new block for store the second part of entries */
uint32_t new_fblock;
uint32_t new_iblock;
rc = ext4_fs_append_inode_block(inode_ref, &new_fblock,
&new_iblock);
if (rc != EOK) {
free(sort_array);
free(entry_buffer);
return rc;
}
/* Load new block */
struct ext4_block new_data_block_tmp;
rc = ext4_block_get(inode_ref->fs->bdev, &new_data_block_tmp,
new_fblock);
if (rc != EOK) {
free(sort_array);
free(entry_buffer);
return rc;
}
/*
* Distribute entries to two blocks (by size)
* - compute the half
*/
uint32_t new_hash = 0;
uint32_t current_size = 0;
uint32_t mid = 0;
uint32_t i;
for ( i = 0; i < idx; ++i) {
if ((current_size + sort_array[i].rec_len) > (block_size / 2)) {
new_hash = sort_array[i].hash;
mid = i;
break;
}
current_size += sort_array[i].rec_len;
}
/* Check hash collision */
uint32_t continued = 0;
if (new_hash == sort_array[mid-1].hash)
continued = 1;
uint32_t offset = 0;
void *ptr;
/* First part - to the old block */
for (i = 0; i < mid; ++i) {
ptr = old_data_block->data + offset;
memcpy(ptr, sort_array[i].dentry, sort_array[i].rec_len);
struct ext4_directory_entry_ll *tmp = ptr;
if (i < (mid - 1))
ext4_dir_entry_ll_set_entry_length(tmp,
sort_array[i].rec_len);
else
ext4_dir_entry_ll_set_entry_length(tmp,
block_size - offset);
offset += sort_array[i].rec_len;
}
/* Second part - to the new block */
offset = 0;
for (i = mid; i < idx; ++i) {
ptr = new_data_block_tmp.data + offset;
memcpy(ptr, sort_array[i].dentry, sort_array[i].rec_len);
struct ext4_directory_entry_ll *tmp = ptr;
if (i < (idx - 1))
ext4_dir_entry_ll_set_entry_length(tmp,
sort_array[i].rec_len);
else
ext4_dir_entry_ll_set_entry_length(tmp,
block_size - offset);
offset += sort_array[i].rec_len;
}
/* Do some steps to finish operation */
old_data_block->dirty = true;
new_data_block_tmp.dirty = true;
free(sort_array);
free(entry_buffer);
ext4_dir_dx_insert_entry(index_block, new_hash + continued,
new_iblock);
*new_data_block = new_data_block_tmp;
return EOK;
}
/**@brief Split index node and maybe some parent nodes in the tree hierarchy.
* @param inode_ref Directory i-node
* @param dx_blocks Array with path from root to leaf node
* @param dx_block Leaf block to be split if needed
* @return Error code
*/
static int ext4_dir_dx_split_index(struct ext4_inode_ref *inode_ref,
struct ext4_directory_dx_block *dx_blocks,
struct ext4_directory_dx_block *dx_block,
struct ext4_directory_dx_block **new_dx_block)
{
struct ext4_directory_dx_entry *entries;
if (dx_block == dx_blocks)
entries =
((struct ext4_directory_dx_root *) dx_block->block.data)->entries;
else
entries =
((struct ext4_directory_dx_node *) dx_block->block.data)->entries;
struct ext4_directory_dx_countlimit *countlimit =
(struct ext4_directory_dx_countlimit *) entries;
uint16_t leaf_limit =
ext4_dir_dx_countlimit_get_limit(countlimit);
uint16_t leaf_count =
ext4_dir_dx_countlimit_get_count(countlimit);
/* Check if is necessary to split index block */
if (leaf_limit == leaf_count) {
size_t levels = dx_block - dx_blocks;
struct ext4_directory_dx_entry *root_entries =
((struct ext4_directory_dx_root *) dx_blocks[0].block.data)->entries;
struct ext4_directory_dx_countlimit *root_countlimit =
(struct ext4_directory_dx_countlimit *) root_entries;
uint16_t root_limit =
ext4_dir_dx_countlimit_get_limit(root_countlimit);
uint16_t root_count =
ext4_dir_dx_countlimit_get_count(root_countlimit);
/* Linux limitation */
if ((levels > 0) && (root_limit == root_count))
return ENOSPC;
/* Add new block to directory */
uint32_t new_fblock;
uint32_t new_iblock;
int rc = ext4_fs_append_inode_block(inode_ref,
&new_fblock, &new_iblock);
if (rc != EOK)
return rc;
/* load new block */
struct ext4_block new_block;
rc = ext4_block_get(inode_ref->fs->bdev, &new_block,
new_fblock);
if (rc != EOK)
return rc;
struct ext4_directory_dx_node *new_node = (void *)new_block.data;
struct ext4_directory_dx_entry *new_entries = new_node->entries;
memset(&new_node->fake, 0, sizeof(struct ext4_fake_directory_entry));
uint32_t block_size =
ext4_sb_get_block_size(&inode_ref->fs->sb);
new_node->fake.entry_length = block_size;
/* Split leaf node */
if (levels > 0) {
uint32_t count_left = leaf_count / 2;
uint32_t count_right = leaf_count - count_left;
uint32_t hash_right =
ext4_dir_dx_entry_get_hash(entries + count_left);
/* Copy data to new node */
memcpy((void *) new_entries, (void *) (entries + count_left),
count_right * sizeof(struct ext4_directory_dx_entry));
/* Initialize new node */
struct ext4_directory_dx_countlimit *left_countlimit =
(struct ext4_directory_dx_countlimit *) entries;
struct ext4_directory_dx_countlimit *right_countlimit =
(struct ext4_directory_dx_countlimit *) new_entries;
ext4_dir_dx_countlimit_set_count(left_countlimit, count_left);
ext4_dir_dx_countlimit_set_count(right_countlimit, count_right);
uint32_t entry_space =
block_size - sizeof(struct ext4_fake_directory_entry);
uint32_t node_limit =
entry_space / sizeof(struct ext4_directory_dx_entry);
ext4_dir_dx_countlimit_set_limit(right_countlimit, node_limit);
/* Which index block is target for new entry */
uint32_t position_index = (dx_block->position - dx_block->entries);
if (position_index >= count_left) {
dx_block->block.dirty = true;
struct ext4_block block_tmp = dx_block->block;
dx_block->block = new_block;
dx_block->position =
new_entries + position_index - count_left;
dx_block->entries = new_entries;
new_block = block_tmp;
}
/* Finally insert new entry */
ext4_dir_dx_insert_entry(dx_blocks, hash_right, new_iblock);
dx_blocks[0].block.dirty = true;
dx_blocks[1].block.dirty = true;
new_block.dirty = true;
return ext4_block_set(inode_ref->fs->bdev, &new_block);
} else {
/* Create second level index */
/* Copy data from root to child block */
memcpy((void *) new_entries, (void *) entries,
leaf_count * sizeof(struct ext4_directory_dx_entry));
struct ext4_directory_dx_countlimit *new_countlimit =
(struct ext4_directory_dx_countlimit *) new_entries;
uint32_t entry_space =
block_size - sizeof(struct ext4_fake_directory_entry);
uint32_t node_limit =
entry_space / sizeof(struct ext4_directory_dx_entry);
ext4_dir_dx_countlimit_set_limit(new_countlimit, node_limit);
/* Set values in root node */
struct ext4_directory_dx_countlimit *new_root_countlimit =
(struct ext4_directory_dx_countlimit *) entries;
ext4_dir_dx_countlimit_set_count(new_root_countlimit, 1);
ext4_dir_dx_entry_set_block(entries, new_iblock);
((struct ext4_directory_dx_root *)
dx_blocks[0].block.data)->info.indirect_levels = 1;
/* Add new entry to the path */
dx_block = dx_blocks + 1;
dx_block->position = dx_blocks->position - entries + new_entries;
dx_block->entries = new_entries;
dx_block->block = new_block;
*new_dx_block = dx_block;
dx_blocks[0].block.dirty = true;
dx_blocks[1].block.dirty = true;
}
}
return EOK;
}
int ext4_dir_dx_add_entry(struct ext4_inode_ref *parent,
struct ext4_inode_ref *child, const char *name)
{
int rc2 = EOK;
/* Get direct block 0 (index root) */
uint32_t root_block_addr;
int rc = ext4_fs_get_inode_data_block_index(parent, 0,
&root_block_addr);
if (rc != EOK)
return rc;
struct ext4_fs *fs = parent->fs;
struct ext4_block root_block;
rc = ext4_block_get(fs->bdev, &root_block, root_block_addr);
if (rc != EOK)
return rc;
/* Initialize hinfo structure (mainly compute hash) */
uint32_t name_len = strlen(name);
struct ext4_hash_info hinfo;
rc = ext4_dir_hinfo_init(&hinfo, &root_block, &fs->sb,
name_len, name);
if (rc != EOK) {
ext4_block_set(fs->bdev, &root_block);
return EXT4_ERR_BAD_DX_DIR;
}
/*
* Hardcoded number 2 means maximum height of index
* tree defined in Linux.
*/
struct ext4_directory_dx_block dx_blocks[2];
struct ext4_directory_dx_block *dx_block;
struct ext4_directory_dx_block *dx_it;
rc = ext4_dir_dx_get_leaf(&hinfo, parent, &root_block,
&dx_block, dx_blocks);
if (rc != EOK) {
rc = EXT4_ERR_BAD_DX_DIR;
goto release_index;
}
/* Try to insert to existing data block */
uint32_t leaf_block_idx =
ext4_dir_dx_entry_get_block(dx_block->position);
uint32_t leaf_block_addr;
rc = ext4_fs_get_inode_data_block_index(parent, leaf_block_idx,
&leaf_block_addr);
if (rc != EOK)
goto release_index;
/*
* Check if there is needed to split index node
* (and recursively also parent nodes)
*/
rc = ext4_dir_dx_split_index(parent, dx_blocks, dx_block, &dx_block);
if (rc != EOK)
goto release_target_index;
struct ext4_block target_block;
rc = ext4_block_get(fs->bdev, &target_block, leaf_block_addr);
if (rc != EOK)
goto release_index;
/* Check if insert operation passed */
rc = ext4_dir_try_insert_entry(&fs->sb, &target_block, child,
name, name_len);
if (rc == EOK)
goto release_target_index;
/* Split entries to two blocks (includes sorting by hash value) */
struct ext4_block new_block;
rc = ext4_dir_dx_split_data(parent, &hinfo, &target_block,
dx_block, &new_block);
if (rc != EOK) {
rc2 = rc;
goto release_target_index;
}
/* Where to save new entry */
uint32_t new_block_hash =
ext4_dir_dx_entry_get_hash(dx_block->position + 1);
if (hinfo.hash >= new_block_hash)
rc = ext4_dir_try_insert_entry(&fs->sb, &new_block,
child, name, name_len);
else
rc = ext4_dir_try_insert_entry(&fs->sb, &target_block,
child, name, name_len);
/* Cleanup */
rc = ext4_block_set(fs->bdev, &new_block);
if (rc != EOK)
return rc;
/* Cleanup operations */
release_target_index:
rc2 = rc;
rc = ext4_block_set(fs->bdev, &target_block);
if (rc != EOK)
return rc;
release_index:
if (rc != EOK)
rc2 = rc;
dx_it = dx_blocks;
while (dx_it <= dx_block) {
rc = ext4_block_set(fs->bdev, &dx_it->block);
if (rc != EOK)
return rc;
dx_it++;
}
return rc2;
}
/**
* @}
*/