source: mainline/uspace/lib/ext4/libext4_filesystem.c@ e5f8762

/*
 * 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_filesystem.c
 * @brief       TODO
 */

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

int ext4_filesystem_init(ext4_filesystem_t *fs, service_id_t service_id)
{
        int rc;
        ext4_superblock_t *temp_superblock;
        size_t block_size;
        uint32_t block_ids_per_block;
        int i;

        fs->device = service_id;

        // TODO what does constant 2048 mean?
        rc = block_init(EXCHANGE_SERIALIZE, fs->device, 2048);
        if (rc != EOK) {
                return rc;
        }

        /* Read superblock from device */
        rc = ext4_superblock_read_direct(fs->device, &temp_superblock);
        if (rc != EOK) {
                block_fini(fs->device);
                return rc;
        }

        /* Read block size from superblock and check */
        block_size = ext4_superblock_get_block_size(temp_superblock);
        if (block_size > EXT4_MAX_BLOCK_SIZE) {
                block_fini(fs->device);
                return ENOTSUP;
        }

        /* Initialize block caching */
        rc = block_cache_init(service_id, block_size, 0, CACHE_MODE_WT);
        if (rc != EOK) {
                block_fini(fs->device);
                return rc;
        }

        block_ids_per_block = block_size / sizeof(uint32_t);
        fs->inode_block_limits[0] = EXT4_INODE_DIRECT_BLOCK_COUNT;
        fs->inode_blocks_per_level[0] = 1;
        for (i = 1; i < 4; i++) {
                fs->inode_blocks_per_level[i] = fs->inode_blocks_per_level[i-1] *
                    block_ids_per_block;
                fs->inode_block_limits[i] = fs->inode_block_limits[i-1] +
                                fs->inode_blocks_per_level[i];
        }

        /* Return loaded superblock */
        fs->superblock = temp_superblock;

        return EOK;
}

int ext4_filesystem_fini(ext4_filesystem_t *fs, bool write_sb)
{
        int rc = EOK;
        if (write_sb) {
                rc = ext4_superblock_write_direct(fs->device, fs->superblock);
        }

        free(fs->superblock);
        block_fini(fs->device);

        return rc;
}

int ext4_filesystem_check_sanity(ext4_filesystem_t *fs)
{
        int rc;

        rc = ext4_superblock_check_sanity(fs->superblock);
        if (rc != EOK) {
                return rc;
        }

        return EOK;
}

int ext4_filesystem_check_features(ext4_filesystem_t *fs, bool *o_read_only)
{
        /* Feature flags are present in rev 1 and later */
        if (ext4_superblock_get_rev_level(fs->superblock) == 0) {
                *o_read_only = false;
                return EOK;
        }

        uint32_t incompatible_features;
        incompatible_features = ext4_superblock_get_features_incompatible(fs->superblock);
        incompatible_features &= ~EXT4_FEATURE_INCOMPAT_SUPP;
        if (incompatible_features > 0) {
                *o_read_only = true;
                return ENOTSUP;
        }

        uint32_t compatible_read_only;
        compatible_read_only = ext4_superblock_get_features_read_only(fs->superblock);
        compatible_read_only &= ~EXT4_FEATURE_RO_COMPAT_SUPP;
        if (compatible_read_only > 0) {
                *o_read_only = true;
        }

        return EOK;
}

int ext4_filesystem_get_block_group_ref(ext4_filesystem_t *fs, uint32_t bgid,
    ext4_block_group_ref_t **ref)
{
        int rc;
        aoff64_t block_id;
        uint32_t descriptors_per_block;
        size_t offset;
        ext4_block_group_ref_t *newref;

        newref = malloc(sizeof(ext4_block_group_ref_t));
        if (newref == NULL) {
                return ENOMEM;
        }

        descriptors_per_block = ext4_superblock_get_block_size(fs->superblock)
            / ext4_superblock_get_desc_size(fs->superblock);

        /* Block group descriptor table starts at the next block after superblock */
        block_id = ext4_superblock_get_first_data_block(fs->superblock) + 1;

        /* Find the block containing the descriptor we are looking for */
        block_id += bgid / descriptors_per_block;
        offset = (bgid % descriptors_per_block) * ext4_superblock_get_desc_size(fs->superblock);

        rc = block_get(&newref->block, fs->device, block_id, 0);
        if (rc != EOK) {
                free(newref);
                return rc;
        }

        newref->block_group = newref->block->data + offset;
        newref->dirty = false;

        *ref = newref;

        return EOK;
}

int ext4_filesystem_put_block_group_ref(ext4_block_group_ref_t *ref)
{
        int rc;

        if (ref->dirty) {
                ref->block->dirty = true;
        }

        rc = block_put(ref->block);
        free(ref);

        return rc;
}

int ext4_filesystem_get_inode_ref(ext4_filesystem_t *fs, uint32_t index,
    ext4_inode_ref_t **ref)
{
        int rc;
        aoff64_t block_id;
        uint32_t block_group;
        uint32_t offset_in_group;
        uint32_t byte_offset_in_group;
        size_t offset_in_block;
        uint32_t inodes_per_group;
        uint32_t inode_table_start;
        uint16_t inode_size;
        uint32_t block_size;
        ext4_block_group_ref_t *bg_ref;
        ext4_inode_ref_t *newref;

        newref = malloc(sizeof(ext4_inode_ref_t));
        if (newref == NULL) {
                return ENOMEM;
        }

        inodes_per_group = ext4_superblock_get_inodes_per_group(fs->superblock);

        /* inode numbers are 1-based, but it is simpler to work with 0-based
         * when computing indices
         */
        index -= 1;
        block_group = index / inodes_per_group;
        offset_in_group = index % inodes_per_group;

        rc = ext4_filesystem_get_block_group_ref(fs, block_group, &bg_ref);
        if (rc != EOK) {
                free(newref);
                return rc;
        }

        inode_table_start = ext4_block_group_get_inode_table_first_block(
            bg_ref->block_group, fs->superblock);

        rc = ext4_filesystem_put_block_group_ref(bg_ref);
        if (rc != EOK) {
                free(newref);
                return rc;
        }

        inode_size = ext4_superblock_get_inode_size(fs->superblock);
        block_size = ext4_superblock_get_block_size(fs->superblock);

        byte_offset_in_group = offset_in_group * inode_size;

        block_id = inode_table_start + (byte_offset_in_group / block_size);
        offset_in_block = byte_offset_in_group % block_size;

        rc = block_get(&newref->block, fs->device, block_id, 0);
        if (rc != EOK) {
                free(newref);
                return rc;
        }

        newref->inode = newref->block->data + offset_in_block;
        /* we decremented index above, but need to store the original value
         * in the reference
         */
        newref->index = index+1;
        newref->dirty = false;

        *ref = newref;

        return EOK;
}


int ext4_filesystem_put_inode_ref(ext4_inode_ref_t *ref)
{
        int rc;

        if (ref->dirty) {
                ref->block->dirty = true;
        }

        rc = block_put(ref->block);
        free(ref);

        return rc;
}

int ext4_filesystem_free_inode(ext4_filesystem_t *fs, ext4_inode_ref_t *inode_ref)
{
        int rc;
        // release all indirect blocks

        uint32_t fblock;

        // 1) Single indirect
        fblock = ext4_inode_get_indirect_block(inode_ref->inode, 0);
        if (fblock != 0) {
                rc = ext4_balloc_free_block(fs, inode_ref, fblock);
                if (rc != EOK) {
                        // TODO error
                }

                ext4_inode_set_indirect_block(inode_ref->inode, 0, 0);
        }

        block_t *block;
        uint32_t block_size = ext4_superblock_get_block_size(fs->superblock);
        uint32_t count = block_size / sizeof(uint32_t);

        // 2) Double indirect
        fblock = ext4_inode_get_indirect_block(inode_ref->inode, 1);
        if (fblock != 0) {
                rc = block_get(&block, fs->device, fblock, BLOCK_FLAGS_NONE);
                if (rc != EOK) {
                        // TODO error
                }

                uint32_t ind_block;
                for (uint32_t offset = 0; offset < count; ++offset) {
                        ind_block = uint32_t_le2host(((uint32_t*)block->data)[offset]);

                        if (ind_block != 0) {
                                rc = ext4_balloc_free_block(fs, inode_ref, ind_block);
                                if (rc != EOK) {
                                        // TODO error
                                }
                        }
                }

                block_put(block);
                rc = ext4_balloc_free_block(fs, inode_ref, fblock);
                if (rc != EOK) {
                        // TODO error
                }

                ext4_inode_set_indirect_block(inode_ref->inode, 1, 0);
        }


        // 3) Tripple indirect
        block_t *subblock;
        fblock = ext4_inode_get_indirect_block(inode_ref->inode, 2);
        if (fblock != 0) {
                rc = block_get(&block, fs->device, fblock, BLOCK_FLAGS_NONE);
                if (rc != EOK) {
                        // TODO error
                }

                uint32_t ind_block;
                for (uint32_t offset = 0; offset < count; ++offset) {
                        ind_block = uint32_t_le2host(((uint32_t*)block->data)[offset]);

                        if (ind_block != 0) {
                                rc = block_get(&subblock, fs->device, ind_block, BLOCK_FLAGS_NONE);
                                if (rc != EOK) {
                                        // TODO error
                                }

                                uint32_t ind_subblock;
                                for (uint32_t suboffset = 0; suboffset < count; ++suboffset) {
                                        ind_subblock = uint32_t_le2host(((uint32_t*)subblock->data)[suboffset]);

                                        if (ind_subblock != 0) {
                                                rc = ext4_balloc_free_block(fs, inode_ref, ind_subblock);
                                                if (rc != EOK) {
                                                        // TODO error
                                                }
                                        }

                                }
                                block_put(subblock);

                        }

                        rc = ext4_balloc_free_block(fs, inode_ref, ind_block);
                        if (rc != EOK) {
                                // TODO error
                        }


                }

                block_put(block);
                rc = ext4_balloc_free_block(fs, inode_ref, fblock);
                if (rc != EOK) {
                        // TODO error
                }

                ext4_inode_set_indirect_block(inode_ref->inode, 2, 0);
        }

        inode_ref->dirty = true;

        // Free inode
        rc = ext4_ialloc_free_inode(fs, inode_ref);
        if (rc != EOK) {
                return rc;
        }

        return EOK;
}

int ext4_filesystem_truncate_inode(ext4_filesystem_t *fs,
                ext4_inode_ref_t *inode_ref, aoff64_t new_size)
{
        aoff64_t old_size;
        aoff64_t size_diff;

        if (! ext4_inode_can_truncate(fs->superblock, inode_ref->inode)) {
                // Unable to truncate
                return EINVAL;
        }

        old_size = ext4_inode_get_size(fs->superblock, inode_ref->inode);

        if (old_size == new_size) {
                // Nothing to do
                return EOK;
        }

        uint32_t block_size;
        uint32_t blocks_count, total_blocks;
        uint32_t i;

        block_size  = ext4_superblock_get_block_size(fs->superblock);

        if (old_size < new_size) {
                // Currently not supported to expand the file
                // TODO
                EXT4FS_DBG("trying to expand the file");
                return EINVAL;
        }

        size_diff = old_size - new_size;
        blocks_count = size_diff / block_size;
        if (size_diff % block_size != 0) {
                blocks_count++;
        }

        total_blocks = old_size / block_size;
        if (old_size % block_size != 0) {
                total_blocks++;
        }

        // starting from 1 because of logical blocks are numbered from 0
        for (i = 1; i <= blocks_count; ++i) {
                // TODO check retval
                ext4_filesystem_release_inode_block(fs, inode_ref, total_blocks - i);
        }

        ext4_inode_set_size(inode_ref->inode, new_size);

        inode_ref->dirty = true;

        return EOK;
}

int ext4_filesystem_get_inode_data_block_index(ext4_filesystem_t *fs, ext4_inode_t* inode,
    aoff64_t iblock, uint32_t* fblock)
{
        int rc;
        uint32_t offset_in_block;
        uint32_t current_block;
        aoff64_t block_offset_in_level;
        int i;
        int level;
        block_t *block;

        /* Handle inode using extents */
        if (ext4_superblock_has_feature_compatible(fs->superblock, EXT4_FEATURE_INCOMPAT_EXTENTS) &&
                        ext4_inode_has_flag(inode, EXT4_INODE_FLAG_EXTENTS)) {
                current_block = ext4_inode_get_extent_block(inode, iblock, fs->device);
                *fblock = current_block;
                return EOK;

        }

        /* Handle simple case when we are dealing with direct reference */
        if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
                current_block = ext4_inode_get_direct_block(inode, (uint32_t)iblock);
                *fblock = current_block;
                return EOK;
        }

        /* Determine the indirection level needed to get the desired block */
        level = -1;
        for (i = 1; i < 4; i++) {
                if (iblock < fs->inode_block_limits[i]) {
                        level = i;
                        break;
                }
        }

        if (level == -1) {
                return EIO;
        }

        /* Compute offsets for the topmost level */
        block_offset_in_level = iblock - fs->inode_block_limits[level-1];
        current_block = ext4_inode_get_indirect_block(inode, level-1);
        offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];

        if (current_block == 0) {
                *fblock = 0;
                return EOK;
        }

        /* Navigate through other levels, until we find the block number
         * or find null reference meaning we are dealing with sparse file
         */
        while (level > 0) {
                rc = block_get(&block, fs->device, current_block, 0);
                if (rc != EOK) {
                        return rc;
                }

                current_block = uint32_t_le2host(((uint32_t*)block->data)[offset_in_block]);

                rc = block_put(block);
                if (rc != EOK) {
                        return rc;
                }

                if (current_block == 0) {
                        /* This is a sparse file */
                        *fblock = 0;
                        return EOK;
                }

                level -= 1;

                /* If we are on the last level, break here as
                 * there is no next level to visit
                 */
                if (level == 0) {
                        break;
                }

                /* Visit the next level */
                block_offset_in_level %= fs->inode_blocks_per_level[level];
                offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];
        }

        *fblock = current_block;

        return EOK;
}


int ext4_filesystem_set_inode_data_block_index(ext4_filesystem_t *fs,
                ext4_inode_ref_t *inode_ref, aoff64_t iblock, uint32_t fblock)
{

        int rc;
        uint32_t offset_in_block;
        uint32_t current_block, new_block_addr;
        uint32_t block_size;
        aoff64_t block_offset_in_level;
        int i;
        int level;
        block_t *block, *new_block;

        /* Handle inode using extents */
        if (ext4_superblock_has_feature_compatible(fs->superblock, EXT4_FEATURE_INCOMPAT_EXTENTS) &&
                        ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS)) {
                // TODO
                return ENOTSUP;
        }

        /* Handle simple case when we are dealing with direct reference */
        if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
                ext4_inode_set_direct_block(inode_ref->inode, (uint32_t)iblock, fblock);
                inode_ref->dirty = true;
                return EOK;
        }

        /* Determine the indirection level needed to get the desired block */
        level = -1;
        for (i = 1; i < 4; i++) {
                if (iblock < fs->inode_block_limits[i]) {
                        level = i;
                        break;
                }
        }

        if (level == -1) {
                return EIO;
        }

        block_size = ext4_superblock_get_block_size(fs->superblock);

        /* Compute offsets for the topmost level */
        block_offset_in_level = iblock - fs->inode_block_limits[level-1];
        current_block = ext4_inode_get_indirect_block(inode_ref->inode, level-1);
        offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];

        if (current_block == 0) {
                rc = ext4_balloc_alloc_block(fs, inode_ref, &new_block_addr);
                if (rc != EOK) {
                        // TODO error
                        EXT4FS_DBG("error in allocation");
                }
//              EXT4FS_DBG("AAA: new addr \%u, level = \%u", new_block_addr, level);

                ext4_inode_set_indirect_block(inode_ref->inode, level - 1, new_block_addr);

                inode_ref->dirty = true;

                rc = block_get(&new_block, fs->device, new_block_addr, BLOCK_FLAGS_NOREAD);
                if (rc != EOK) {
                        EXT4FS_DBG("block load error");
                        // TODO error
                }

                memset(new_block->data, 0, block_size);
                new_block->dirty = true;

                rc = block_put(new_block);
                if (rc != EOK) {
                        EXT4FS_DBG("block put error");
                }

//              EXT4FS_DBG("allocated indirect block for level \%u, during setting iblock \%u", level, (uint32_t)iblock);

                current_block = new_block_addr;
        }

        /* Navigate through other levels, until we find the block number
         * or find null reference meaning we are dealing with sparse file
         */
        while (level > 0) {

                rc = block_get(&block, fs->device, current_block, 0);
                if (rc != EOK) {
                        return rc;
                }

                current_block = uint32_t_le2host(((uint32_t*)block->data)[offset_in_block]);

                if ((level > 1) && (current_block == 0)) {
                        rc = ext4_balloc_alloc_block(fs, inode_ref, &new_block_addr);
                        if (rc != EOK) {
                                // TODO error
                                EXT4FS_DBG("allocation error");
                        }
//                      EXT4FS_DBG("BBB: new addr \%u, offset = \%u, level = \%u", new_block_addr, offset_in_block, level);

                        rc = block_get(&new_block, fs->device, new_block_addr, BLOCK_FLAGS_NOREAD);
                        if (rc != EOK) {
                                // TODO error

                                EXT4FS_DBG("BBB: error block loading");

                        }
                        memset(new_block->data, 0, block_size);
                        new_block->dirty = true;

                        rc = block_put(new_block);
                        if (rc != EOK) {
                                EXT4FS_DBG("BBB: error indirect block saving");
                        }

                        ((uint32_t*)block->data)[offset_in_block] = host2uint32_t_le(new_block_addr);
                        block->dirty = true;
                        current_block = new_block_addr;
                }

                if (level == 1) {
                        ((uint32_t*)block->data)[offset_in_block] = host2uint32_t_le(fblock);
                        block->dirty = true;
                }

                rc = block_put(block);
                if (rc != EOK) {
                        return rc;
                }

                level -= 1;

                /* If we are on the last level, break here as
                 * there is no next level to visit
                 */
                if (level == 0) {
                        break;
                }

                /* Visit the next level */
                block_offset_in_level %= fs->inode_blocks_per_level[level];
                offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];
        }

        return EOK;
}

int ext4_filesystem_release_inode_block(ext4_filesystem_t *fs,
                ext4_inode_ref_t *inode_ref, uint32_t iblock)
{
        int rc;
        uint32_t fblock;
        int i;
        int level;
        aoff64_t block_offset_in_level;
        uint32_t current_block;
        uint32_t offset_in_block;
        block_t *block;
        ext4_inode_t *inode = inode_ref->inode;

        /* TODO handle extents */


        /* Handle simple case when we are dealing with direct reference */
        if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
                fblock = ext4_inode_get_direct_block(inode, iblock);
                // Sparse file
                if (fblock == 0) {
                        return EOK;
                }

                ext4_inode_set_direct_block(inode, iblock, 0);
                return ext4_balloc_free_block(fs, inode_ref, fblock);
        }


        /* Determine the indirection level needed to get the desired block */
        level = -1;
        for (i = 1; i < 4; i++) {
                if (iblock < fs->inode_block_limits[i]) {
                        level = i;
                        break;
                }
        }

        if (level == -1) {
                return EIO;
        }

        /* Compute offsets for the topmost level */
        block_offset_in_level = iblock - fs->inode_block_limits[level-1];
        current_block = ext4_inode_get_indirect_block(inode, level-1);
        offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];

        /* Navigate through other levels, until we find the block number
         * or find null reference meaning we are dealing with sparse file
         */
        while (level > 0) {
                rc = block_get(&block, fs->device, current_block, 0);
                if (rc != EOK) {
                        return rc;
                }

                current_block = uint32_t_le2host(((uint32_t*)block->data)[offset_in_block]);

                // Set zero
                if (level == 1) {
                        ((uint32_t*)block->data)[offset_in_block] = host2uint32_t_le(0);
                        block->dirty = true;
                }

                rc = block_put(block);
                if (rc != EOK) {
                        return rc;
                }

                level -= 1;

                /* If we are on the last level, break here as
                 * there is no next level to visit
                 */
                if (level == 0) {
                        break;
                }

                /* Visit the next level */
                block_offset_in_level %= fs->inode_blocks_per_level[level];
                offset_in_block = block_offset_in_level / fs->inode_blocks_per_level[level-1];
        }

        fblock = current_block;

        if (fblock == 0) {
                return EOK;
        }

        return ext4_balloc_free_block(fs, inode_ref, fblock);

}

/**
 * @}
 */