static struct ext4_directory_dx_countlimit *
ext4_dir_dx_get_countlimit(struct ext4_inode_ref *inode_ref,
struct ext4_directory_entry_ll *dirent,
int *offset)
{
struct ext4_directory_entry_ll *dp;
struct ext4_directory_dx_root *root;
struct ext4_sblock *sb = &inode_ref->fs->sb;
int count_offset;
if (ext4_dir_entry_ll_get_entry_length(dirent) ==
ext4_sb_get_block_size(sb))
count_offset = 8;
else if (ext4_dir_entry_ll_get_entry_length(dirent) == 12) {
root = (struct ext4_directory_dx_root *)dirent;
dp = (struct ext4_directory_entry_ll *)&root->dots[1];
if (ext4_dir_entry_ll_get_entry_length(dp) !=
ext4_sb_get_block_size(sb) - 12)
return NULL;
if (root->info.reserved_zero ||
root->info.info_length != sizeof(struct ext4_directory_dx_root_info))
return NULL;
count_offset = 32;
} else
return NULL;
if (offset)
*offset = count_offset;
return (struct ext4_directory_dx_countlimit *)(((char *)dirent) + count_offset);
}
uint32_t ext4_num_base_meta_clusters(struct ext4_sblock *s,
uint32_t block_group)
{
uint32_t num;
uint32_t dsc_per_block =
ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
num = ext4_sb_is_super_in_bg(s, block_group);
if (!ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG) ||
block_group < ext4_sb_first_meta_bg(s) * dsc_per_block) {
if (num) {
num += ext4_bg_num_gdb(s, block_group);
num += ext4_get16(s, s_reserved_gdt_blocks);
}
} else {
num += ext4_bg_num_gdb(s, block_group);
}
uint32_t clustersize = 1024 << ext4_get32(s, log_cluster_size);
uint32_t cluster_ratio = clustersize / ext4_sb_get_block_size(s);
uint32_t v =
(num + cluster_ratio - 1) >> ext4_get32(s, log_cluster_size);
return v;
}
static void
ext4_dir_set_dx_checksum(struct ext4_inode_ref *inode_ref,
struct ext4_directory_entry_ll *dirent)
{
int count_offset, limit, count;
struct ext4_sblock *sb = &inode_ref->fs->sb;
if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
struct ext4_directory_dx_countlimit *countlimit =
ext4_dir_dx_get_countlimit(inode_ref, dirent, &count_offset);
if (!countlimit) {
/* Directory seems corrupted. */
return;
}
struct ext4_directory_dx_tail *t;
limit = ext4_dir_dx_countlimit_get_limit(countlimit);
count = ext4_dir_dx_countlimit_get_count(countlimit);
if (count_offset + (limit * sizeof(struct ext4_directory_dx_entry)) >
ext4_sb_get_block_size(sb) -
sizeof(struct ext4_directory_dx_tail)) {
/* There is no space to hold the checksum */
return;
}
t = (struct ext4_directory_dx_tail *)
(((struct ext4_directory_dx_entry *)countlimit) + limit);
t->checksum =
to_le32(ext4_dir_dx_checksum(inode_ref, dirent, count_offset, count, t));
}
}
/**@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);
if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
entry_space -= sizeof(struct ext4_directory_dx_tail);
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;
}
uint32_t ext4_bg_num_gdb(struct ext4_sblock *s, uint32_t group)
{
uint32_t dsc_per_block =
ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
uint32_t first_meta_bg = ext4_sb_first_meta_bg(s);
uint32_t metagroup = group / dsc_per_block;
if (!ext4_sb_feature_incom(s,EXT4_FINCOM_META_BG) ||
metagroup < first_meta_bg)
return ext4_bg_num_gdb_nometa(s, group);
return ext4_bg_num_gdb_meta(s, group);
}
static uint32_t ext4_bg_num_gdb_meta(struct ext4_sblock *s, uint32_t group)
{
uint32_t dsc_per_block =
ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
uint32_t metagroup = group / dsc_per_block;
uint32_t first = metagroup * dsc_per_block;
uint32_t last = first + dsc_per_block - 1;
if (group == first || group == first + 1 || group == last)
return 1;
return 0;
}
static uint32_t ext4_bg_num_gdb_nometa(struct ext4_sblock *s, uint32_t group)
{
if (!ext4_sb_is_super_in_bg(s, group))
return 0;
uint32_t dsc_per_block =
ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
uint32_t db_count =
(ext4_block_group_cnt(s) + dsc_per_block - 1) / dsc_per_block;
if (ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG))
return ext4_sb_first_meta_bg(s);
return db_count;
}
/**@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--;
ext4_fsblk_t fblock;
int rc = ext4_fs_get_inode_data_block_index(
inode_ref, next_block, &fblock, false);
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);
if (ext4_sb_feature_ro_com(&inode_ref->fs->sb,
EXT4_FRO_COM_METADATA_CSUM))
entry_space -= sizeof(struct ext4_directory_dx_tail);
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;
}
int ext4_dir_dx_init(struct ext4_inode_ref *dir, struct ext4_inode_ref *parent)
{
/* Load block 0, where will be index root located */
ext4_fsblk_t fblock;
uint32_t iblock;
struct ext4_sblock *sb = &dir->fs->sb;
int rc = ext4_fs_append_inode_block(dir, &fblock, &iblock);
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 dot entries */
ext4_dir_write_entry(&dir->fs->sb,
(struct ext4_directory_entry_ll *)root->dots,
12,
dir,
".",
strlen("."));
ext4_dir_write_entry(&dir->fs->sb,
(struct ext4_directory_entry_ll *)(root->dots + 1),
ext4_sb_get_block_size(sb) - 12,
parent,
"..",
strlen(".."));
/* 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);
if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
entry_space -= sizeof(struct ext4_directory_dx_tail);
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 */
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;
if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
ext4_dir_entry_ll_set_entry_length(block_entry,
block_size -
sizeof(struct ext4_directory_entry_tail));
ext4_dir_entry_ll_set_name_length(sb,
block_entry,
0);
ext4_dir_entry_ll_set_inode_type(sb,
block_entry,
EXT4_DIRENTRY_UNKNOWN);
initialize_dir_tail(EXT4_DIRENT_TAIL(block_entry,
ext4_sb_get_block_size(sb)));
ext4_dir_set_checksum(dir,
(struct ext4_directory_entry_ll *)new_block.data);
} else {
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);
ext4_dir_set_dx_checksum(dir,
(struct ext4_directory_entry_ll *)block.data);
block.dirty = true;
return ext4_block_set(dir->fs->bdev, &block);
}
