source: mainline/uspace/lib/ext4/libext4_directory_index.c@ ac92b85

/*
 * Copyright (c) 2011 Frantisek Princ
 * 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 libext4
 * @{
 */ 

/**
 * @file        libext4_directory_index.c
 * @brief       Ext4 directory index operations.
 */

#include <byteorder.h>
#include <errno.h>
#include <malloc.h>
#include <sort.h>
#include <string.h>
#include "libext4.h"


uint8_t ext4_directory_dx_root_info_get_hash_version(
                ext4_directory_dx_root_info_t *root_info)
{
        return root_info->hash_version;
}

void ext4_directory_dx_root_info_set_hash_version(
                ext4_directory_dx_root_info_t *root_info, uint8_t version)
{
        root_info->hash_version = version;
}

uint8_t ext4_directory_dx_root_info_get_info_length(
                ext4_directory_dx_root_info_t *root_info)
{
        return root_info->info_length;
}

void ext4_directory_dx_root_info_set_info_length(
                ext4_directory_dx_root_info_t *root_info, uint8_t info_length)
{
        root_info->info_length = info_length;
}

uint8_t ext4_directory_dx_root_info_get_indirect_levels(
                ext4_directory_dx_root_info_t *root_info)
{
        return root_info->indirect_levels;
}

void ext4_directory_dx_root_info_set_indirect_levels(
                ext4_directory_dx_root_info_t *root_info, uint8_t levels)
{
        root_info->indirect_levels = levels;
}

uint16_t ext4_directory_dx_countlimit_get_limit(
                ext4_directory_dx_countlimit_t *countlimit)
{
        return uint16_t_le2host(countlimit->limit);
}

void ext4_directory_dx_countlimit_set_limit(
                ext4_directory_dx_countlimit_t *countlimit, uint16_t limit)
{
        countlimit->limit = host2uint16_t_le(limit);
}

uint16_t ext4_directory_dx_countlimit_get_count(
                ext4_directory_dx_countlimit_t *countlimit)
{
        return uint16_t_le2host(countlimit->count);
}

void ext4_directory_dx_countlimit_set_count(
                ext4_directory_dx_countlimit_t *countlimit, uint16_t count)
{
        countlimit->count = host2uint16_t_le(count);
}

uint32_t ext4_directory_dx_entry_get_hash(ext4_directory_dx_entry_t *entry)
{
        return uint32_t_le2host(entry->hash);
}

void ext4_directory_dx_entry_set_hash(ext4_directory_dx_entry_t *entry,
                uint32_t hash)
{
        entry->hash = host2uint32_t_le(hash);
}

uint32_t ext4_directory_dx_entry_get_block(ext4_directory_dx_entry_t *entry)
{
        return uint32_t_le2host(entry->block);
}

void ext4_directory_dx_entry_set_block(ext4_directory_dx_entry_t *entry,
                uint32_t block)
{
        entry->block = host2uint32_t_le(block);
}


/**************************************************************************/


static int ext4_directory_hinfo_init(ext4_hash_info_t *hinfo, block_t *root_block,
                ext4_superblock_t *sb, size_t name_len, const char *name)
{

        ext4_directory_dx_root_t *root = (ext4_directory_dx_root_t *)root_block->data;

        if (root->info.hash_version != EXT4_HASH_VERSION_TEA &&
                        root->info.hash_version != EXT4_HASH_VERSION_HALF_MD4 &&
                        root->info.hash_version != EXT4_HASH_VERSION_LEGACY) {
                return EXT4_ERR_BAD_DX_DIR;
        }

        // Check unused flags
        if (root->info.unused_flags != 0) {
                EXT4FS_DBG("ERR: unused_flags = \%u", root->info.unused_flags);
                return EXT4_ERR_BAD_DX_DIR;
        }

        // Check indirect levels
        if (root->info.indirect_levels > 1) {
                EXT4FS_DBG("ERR: indirect_levels = \%u", root->info.indirect_levels);
                return EXT4_ERR_BAD_DX_DIR;
        }

        uint32_t block_size = ext4_superblock_get_block_size(sb);

        uint32_t entry_space = block_size;
        entry_space -= 2 * sizeof(ext4_directory_dx_dot_entry_t);
        entry_space -= sizeof(ext4_directory_dx_root_info_t);
    entry_space = entry_space / sizeof(ext4_directory_dx_entry_t);

    uint16_t limit = ext4_directory_dx_countlimit_get_limit((ext4_directory_dx_countlimit_t *)&root->entries);
    if (limit != entry_space) {
        return EXT4_ERR_BAD_DX_DIR;
        }

        hinfo->hash_version = ext4_directory_dx_root_info_get_hash_version(&root->info);
        if ((hinfo->hash_version <= EXT4_HASH_VERSION_TEA)
                        && (ext4_superblock_has_flag(sb, EXT4_SUPERBLOCK_FLAGS_UNSIGNED_HASH))) {
                // 3 is magic from ext4 linux implementation
                hinfo->hash_version += 3;
        }

        hinfo->seed = ext4_superblock_get_hash_seed(sb);

        if (name) {
                ext4_hash_string(hinfo, name_len, name);
        }

        return EOK;
}

static int ext4_directory_dx_get_leaf(ext4_hash_info_t *hinfo,
                ext4_filesystem_t *fs, ext4_inode_t *inode, block_t *root_block,
                ext4_directory_dx_block_t **dx_block, ext4_directory_dx_block_t *dx_blocks)
{
        int rc;

        ext4_directory_dx_block_t *tmp_dx_block = dx_blocks;

        ext4_directory_dx_root_t *root = (ext4_directory_dx_root_t *)root_block->data;
        ext4_directory_dx_entry_t *entries = (ext4_directory_dx_entry_t *)&root->entries;

        uint16_t limit = ext4_directory_dx_countlimit_get_limit((ext4_directory_dx_countlimit_t *)entries);
        uint8_t indirect_level = ext4_directory_dx_root_info_get_indirect_levels(&root->info);

        block_t *tmp_block = root_block;
        ext4_directory_dx_entry_t *p, *q, *m, *at;
        while (true) {

                uint16_t count = ext4_directory_dx_countlimit_get_count((ext4_directory_dx_countlimit_t *)entries);
                if ((count == 0) || (count > limit)) {
                        return EXT4_ERR_BAD_DX_DIR;
                }

                p = entries + 1;
                q = entries + count - 1;

                while (p <= q) {
                        m = p + (q - p) / 2;
                        if (ext4_directory_dx_entry_get_hash(m) > hinfo->hash) {
                                q = m - 1;
                        } else {
                                p = m + 1;
                        }
                }

                at = p - 1;

                tmp_dx_block->block = tmp_block;
                tmp_dx_block->entries = entries;
                tmp_dx_block->position = at;

        if (indirect_level == 0) {
                *dx_block = tmp_dx_block;
                return EOK;
        }

                uint32_t next_block = ext4_directory_dx_entry_get_block(at);

        indirect_level--;

        uint32_t fblock;
        rc = ext4_filesystem_get_inode_data_block_index(fs, inode, next_block, &fblock);
        if (rc != EOK) {
                return rc;
        }

        rc = block_get(&tmp_block, fs->device, fblock, BLOCK_FLAGS_NONE);
        if (rc != EOK) {
                return rc;
        }

                entries = ((ext4_directory_dx_node_t *) tmp_block->data)->entries;
                limit = ext4_directory_dx_countlimit_get_limit((ext4_directory_dx_countlimit_t *)entries);

        uint16_t entry_space = ext4_superblock_get_block_size(fs->superblock)
                        - sizeof(ext4_directory_dx_dot_entry_t);
        entry_space = entry_space / sizeof(ext4_directory_dx_entry_t);


                if (limit != entry_space) {
                        block_put(tmp_block);
                return EXT4_ERR_BAD_DX_DIR;
                }

                ++tmp_dx_block;
        }

        // Unreachable
        return EOK;
}


static int ext4_directory_dx_find_dir_entry(block_t *block,
                ext4_superblock_t *sb, size_t name_len, const char *name,
                ext4_directory_entry_ll_t **res_entry, aoff64_t *block_offset)
{

        aoff64_t offset = 0;
        ext4_directory_entry_ll_t *dentry = (ext4_directory_entry_ll_t *)block->data;
        uint8_t *addr_limit = block->data + ext4_superblock_get_block_size(sb);

        while ((uint8_t *)dentry < addr_limit) {

                if ((uint8_t*) dentry + name_len > addr_limit) {
                        break;
                }

                if (dentry->inode != 0) {
                        if (name_len == ext4_directory_entry_ll_get_name_length(sb, dentry)) {
                                // Compare names
                                if (bcmp((uint8_t *)name, dentry->name, name_len) == 0) {
                                        *block_offset = offset;
                                        *res_entry = dentry;
                                        return 1;
                                }
                        }
                }


                // Goto next entry
                uint16_t dentry_len = ext4_directory_entry_ll_get_entry_length(dentry);

        if (dentry_len == 0) {
                // TODO error
                return -1;
        }

                offset += dentry_len;
                dentry = (ext4_directory_entry_ll_t *)((uint8_t *)dentry + dentry_len);
        }

        return 0;
}

static int ext4_directory_dx_next_block(ext4_filesystem_t *fs, ext4_inode_t *inode, uint32_t hash,
                ext4_directory_dx_block_t *handle, ext4_directory_dx_block_t *handles)
{
        int rc;


    uint32_t num_handles = 0;
    ext4_directory_dx_block_t *p = handle;

    while (1) {

        p->position++;
        uint16_t count = ext4_directory_dx_countlimit_get_count((ext4_directory_dx_countlimit_t *)p->entries);

        if (p->position < p->entries + count) {
                break;
        }

        if (p == handles) {
                return 0;
        }

        num_handles++;
        p--;
    }

    uint32_t current_hash = ext4_directory_dx_entry_get_hash(p->position);

    if ((hash & 1) == 0) {
        if ((current_hash & ~1) != hash) {
                return 0;
        }
    }


    while (num_handles--) {

        uint32_t block_idx = ext4_directory_dx_entry_get_block(p->position);
        uint32_t block_addr;
        rc = ext4_filesystem_get_inode_data_block_index(fs, inode, block_idx, &block_addr);
        if (rc != EOK) {
                return rc;
        }

        block_t *block;
        rc = block_get(&block, fs->device, block_addr, BLOCK_FLAGS_NONE);
        if (rc != EOK) {
                return rc;
        }

        p++;

        block_put(p->block);
        p->block = block;
        p->entries = ((ext4_directory_dx_node_t *) block->data)->entries;
        p->position = p->entries;
    }

    return 1;

}

int ext4_directory_dx_find_entry(ext4_directory_iterator_t *it,
                ext4_filesystem_t *fs, ext4_inode_ref_t *inode_ref, size_t len, const char *name)
{
        int rc;

        // get direct block 0 (index root)
        uint32_t root_block_addr;
        rc = ext4_filesystem_get_inode_data_block_index(fs, inode_ref->inode, 0, &root_block_addr);
        if (rc != EOK) {
                return rc;
        }

        block_t *root_block;
        rc = block_get(&root_block, fs->device, root_block_addr, BLOCK_FLAGS_NONE);
        if (rc != EOK) {
                it->current_block = NULL;
                return rc;
        }

        ext4_hash_info_t hinfo;
        rc = ext4_directory_hinfo_init(&hinfo, root_block, fs->superblock, len, name);
        if (rc != EOK) {
                block_put(root_block);
                return EXT4_ERR_BAD_DX_DIR;
        }

        // Hardcoded number 2 means maximum height of index tree !!!
        ext4_directory_dx_block_t dx_blocks[2];
        ext4_directory_dx_block_t *dx_block;
        rc = ext4_directory_dx_get_leaf(&hinfo, fs, inode_ref->inode, root_block, &dx_block, dx_blocks);
        if (rc != EOK) {
                block_put(root_block);
                return EXT4_ERR_BAD_DX_DIR;
        }


        do {

                uint32_t leaf_block_idx = ext4_directory_dx_entry_get_block(dx_block->position);
                uint32_t leaf_block_addr;
        rc = ext4_filesystem_get_inode_data_block_index(fs, inode_ref->inode, leaf_block_idx, &leaf_block_addr);
        if (rc != EOK) {
                return EXT4_ERR_BAD_DX_DIR;
        }

        block_t *leaf_block;
                rc = block_get(&leaf_block, fs->device, leaf_block_addr, BLOCK_FLAGS_NONE);
                if (rc != EOK) {
                        return EXT4_ERR_BAD_DX_DIR;
                }

                aoff64_t block_offset;
                ext4_directory_entry_ll_t *res_dentry;
                rc = ext4_directory_dx_find_dir_entry(leaf_block, fs->superblock, len, name,
                                &res_dentry, &block_offset);

                // Found => return it
                if (rc == 1) {
                        it->fs = fs;
                        it->inode_ref = inode_ref;
                        it->current_block = leaf_block;
                        it->current_offset = block_offset;
                        it->current = res_dentry;
                        return EOK;
                }

                block_put(leaf_block);

                // ERROR - corrupted index
                if (rc == -1) {
                        // TODO cleanup
                        return EXT4_ERR_BAD_DX_DIR;
                }

                rc = ext4_directory_dx_next_block(fs, inode_ref->inode, hinfo.hash, dx_block, &dx_blocks[0]);
                if (rc < 0) {
                        // TODO cleanup
                        return EXT4_ERR_BAD_DX_DIR;
                }

        } while (rc == 1);

        return ENOENT;
}

typedef struct ext4_dx_sort_entry {
        uint32_t hash;
        ext4_directory_entry_ll_t *dentry;
} ext4_dx_sort_entry_t;

static int dx_entry_comparator(void *arg1, void *arg2, void *dummy)
{
        ext4_dx_sort_entry_t *entry1 = arg1;
        ext4_dx_sort_entry_t *entry2 = arg2;

        if (entry1->hash == entry2->hash) {
                return 0;
        }

        if (entry1->hash < entry2->hash) {
                return -1;
        } else {
                return 1;
        }

}

static int ext4_directory_dx_split_data(ext4_filesystem_t *fs,
                ext4_inode_ref_t *inode_ref, ext4_hash_info_t *hinfo,
                block_t *data_block, ext4_directory_dx_block_t *index_block)
{
        int rc;

        uint32_t block_size = ext4_superblock_get_block_size(fs->superblock);
        void *entry_buffer = malloc(block_size);
        if (entry_buffer == NULL) {
                return ENOMEM;
        }

        // Copy data to buffer
        memcpy(entry_buffer, index_block->block->data, block_size);

        ext4_directory_dx_countlimit_t *countlimit =
                        (ext4_directory_dx_countlimit_t *)index_block->entries;
        uint32_t entry_count = ext4_directory_dx_countlimit_get_count(countlimit);
        ext4_dx_sort_entry_t *sort_array = malloc(entry_count);
        if (sort_array == NULL) {
                free(entry_buffer);
                return ENOMEM;
        }

        ext4_directory_entry_ll_t *dentry = data_block->data;

        int idx = 0;
        while ((void *)dentry < data_block->data + block_size) {
                char *name = (char *)dentry->name;
                uint8_t len = ext4_directory_entry_ll_get_name_length(fs->superblock, dentry);
                uint32_t hash = ext4_hash_string(hinfo, len, name);

                sort_array[idx].dentry = dentry;
                sort_array[idx].hash = hash;

                idx++;
                dentry = (void *)dentry + ext4_directory_entry_ll_get_entry_length(dentry);
        }

        qsort(sort_array, entry_count, sizeof(ext4_dx_sort_entry_t), dx_entry_comparator, NULL);

        // TODO split to two groups (by size, NOT by count)

        uint32_t new_fblock;
        rc = ext4_directory_append_block(fs, inode_ref, &new_fblock);
        if (rc != EOK) {
                free(sort_array);
                free(entry_buffer);
                return rc;
        }

        // TODO load new_block

        // TODO write splitted entries to two blocks

        // TODO add new entry to index block

        return EOK;
}


int ext4_directory_dx_add_entry(ext4_filesystem_t *fs,
                ext4_inode_ref_t *parent, ext4_inode_ref_t *child,
                size_t name_size, const char *name)
{
        int rc;

        // get direct block 0 (index root)
        uint32_t root_block_addr;
        rc = ext4_filesystem_get_inode_data_block_index(fs, parent->inode, 0, &root_block_addr);
        if (rc != EOK) {
                return rc;
        }

        block_t *root_block;
        rc = block_get(&root_block, fs->device, root_block_addr, BLOCK_FLAGS_NONE);
        if (rc != EOK) {
                return rc;
        }

        ext4_hash_info_t hinfo;
        rc = ext4_directory_hinfo_init(&hinfo, root_block, fs->superblock, name_size, name);
        if (rc != EOK) {
                block_put(root_block);
                return EXT4_ERR_BAD_DX_DIR;
        }

        // Hardcoded number 2 means maximum height of index tree !!!
        ext4_directory_dx_block_t dx_blocks[2];
        ext4_directory_dx_block_t *dx_block;
        rc = ext4_directory_dx_get_leaf(&hinfo, fs, parent->inode, root_block, &dx_block, dx_blocks);
        if (rc != EOK) {
                block_put(root_block);
                return EXT4_ERR_BAD_DX_DIR;
        }


        // Try to insert to existing data block
        uint32_t leaf_block_idx = ext4_directory_dx_entry_get_block(dx_block->position);
        uint32_t leaf_block_addr;
        rc = ext4_filesystem_get_inode_data_block_index(fs, parent->inode, leaf_block_idx, &leaf_block_addr);
        if (rc != EOK) {
                return EXT4_ERR_BAD_DX_DIR;
        }


        block_t *target;
        rc = block_get(&target, fs->device, leaf_block_addr, BLOCK_FLAGS_NONE);
        if (rc != EOK) {
                return EXT4_ERR_BAD_DX_DIR;
        }

        uint32_t block_size = ext4_superblock_get_block_size(fs->superblock);
        uint16_t required_len = 8 + name_size + (4 - name_size % 4);

        ext4_directory_entry_ll_t *de = target->data;
        ext4_directory_entry_ll_t *stop = target->data + block_size;

        while (de < stop) {

                uint32_t de_inode = ext4_directory_entry_ll_get_inode(de);
                uint16_t de_rec_len = ext4_directory_entry_ll_get_entry_length(de);

                if ((de_inode == 0) && (de_rec_len >= required_len)) {
                        ext4_directory_write_entry(fs->superblock, de, de_rec_len,
                                child, name, name_size);
                                target->dirty = true;
                                rc = block_put(target);
                                if (rc != EOK) {
                                        return EXT4_ERR_BAD_DX_DIR;
                                }
                                return EOK;
                }

                if (de_inode != 0) {
                        uint16_t used_name_len = ext4_directory_entry_ll_get_name_length(
                                        fs->superblock, de);

                        uint16_t used_space = 8 + used_name_len;
                        if ((used_name_len % 4) != 0) {
                                used_space += 4 - (used_name_len % 4);
                        }
                        uint16_t free_space = de_rec_len - used_space;

                        if (free_space >= required_len) {

                                EXT4FS_DBG("rec_len = \%u, used_space = \%u, free space = \%u", de_rec_len, used_space, free_space);

                                // Cut tail of current entry
                                ext4_directory_entry_ll_set_entry_length(de, used_space);
                                ext4_directory_entry_ll_t *new_entry = (void *)de + used_space;
                                ext4_directory_write_entry(fs->superblock, new_entry,
                                        free_space, child, name, name_size);
                                target->dirty = true;
                                rc = block_put(target);
                                if (rc != EOK) {
                                        return EXT4_ERR_BAD_DX_DIR;
                                }
                                return EOK;

                        }

                }

                de = (void *)de + de_rec_len;
        }

    EXT4FS_DBG("no free space found");

        ext4_directory_dx_entry_t *entries = ((ext4_directory_dx_node_t *) dx_block->block->data)->entries;
        uint16_t leaf_limit = ext4_directory_dx_countlimit_get_limit((ext4_directory_dx_countlimit_t *)entries);
        uint16_t leaf_count = ext4_directory_dx_countlimit_get_count((ext4_directory_dx_countlimit_t *)entries);

        ext4_directory_dx_entry_t *root_entries = ((ext4_directory_dx_node_t *) dx_blocks[0].block->data)->entries;

        if (leaf_limit == leaf_count) {
                EXT4FS_DBG("need to split index block !!!");

                unsigned int levels = dx_block - dx_blocks;

                uint16_t root_limit = ext4_directory_dx_countlimit_get_limit((ext4_directory_dx_countlimit_t *)root_entries);
                uint16_t root_count = ext4_directory_dx_countlimit_get_count((ext4_directory_dx_countlimit_t *)root_entries);

                if ((levels > 0) && (root_limit == root_count)) {
                        EXT4FS_DBG("Directory index is full");

                        // ENOSPC - cleanup !!!
                        return ENOSPC;
                }

                uint32_t fblock;
                rc =  ext4_directory_append_block(fs, parent, &fblock);
                if (rc != EOK) {
                        // TODO error
                }

                // New block allocated
                block_t * new_block;
                rc = block_get(&new_block, fs->device, fblock, BLOCK_FLAGS_NOREAD);
                if (rc != EOK) {
                        // TODO error
                }

                memset(new_block->data, 0, block_size);

                if (levels > 0) {
                        EXT4FS_DBG("split index");
                } else {
                        EXT4FS_DBG("create second level");
                }
        }

        rc = ext4_directory_dx_split_data(fs, parent, &hinfo, target, dx_block);
        if (rc != EOK) {
                // TODO error
        }


        // TODO
        return EOK;

}


/**
 * @}
 */