/* * Copyright (c) 2012 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_balloc.c * @brief Physical block allocator. */ #include #include #include "libext4.h" /** Convert block address to relative index in block group. * * @param sb superblock pointer * @param block_addr block number to convert * @return relative number of block */ static uint32_t ext4_balloc_blockaddr2_index_in_group(ext4_superblock_t *sb, uint32_t block_addr) { uint32_t blocks_per_group = ext4_superblock_get_blocks_per_group(sb); uint32_t first_block = ext4_superblock_get_first_data_block(sb); // First block == 0 or 1 if (first_block == 0) { return block_addr % blocks_per_group; } else { return (block_addr - 1) % blocks_per_group; } } /** Convert relative block number to absolute. * * @param sb superblock pointer * @param index relative index of block in group * @param bgid index of block group * @return absolute number of block */ static uint32_t ext4_balloc_index_in_group2blockaddr(ext4_superblock_t *sb, uint32_t index, uint32_t bgid) { uint32_t blocks_per_group = ext4_superblock_get_blocks_per_group(sb); if (ext4_superblock_get_first_data_block(sb) == 0) { return bgid * blocks_per_group + index; } else { return bgid * blocks_per_group + index + 1; } } /** Compute number of block group from block address. * * @param sb superblock pointer * @param block_addr absolute address of block * @return block group index */ static uint32_t ext4_balloc_get_bgid_of_block(ext4_superblock_t *sb, uint32_t block_addr) { uint32_t blocks_per_group = ext4_superblock_get_blocks_per_group(sb); uint32_t first_block = ext4_superblock_get_first_data_block(sb); // First block == 0 or 1 if (first_block == 0) { return block_addr / blocks_per_group; } else { return (block_addr - 1) / blocks_per_group; } } /** Free block. * * @param inode_ref inode, where the block is allocated * @param block_addr absolute block address to free * @return error code */ int ext4_balloc_free_block(ext4_inode_ref_t *inode_ref, uint32_t block_addr) { int rc; ext4_filesystem_t *fs = inode_ref->fs; ext4_superblock_t *sb = fs->superblock; // Compute indexes uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, block_addr); uint32_t index_in_group = ext4_balloc_blockaddr2_index_in_group(sb, block_addr); // Load block group reference ext4_block_group_ref_t *bg_ref; rc = ext4_filesystem_get_block_group_ref(fs, block_group, &bg_ref); if (rc != EOK) { EXT4FS_DBG("error in loading bg_ref \%d", rc); return rc; } // Load block with bitmap uint32_t bitmap_block_addr = ext4_block_group_get_block_bitmap( bg_ref->block_group, sb); block_t *bitmap_block; rc = block_get(&bitmap_block, fs->device, bitmap_block_addr, 0); if (rc != EOK) { EXT4FS_DBG("error in loading bitmap \%d", rc); return rc; } // Modify bitmap ext4_bitmap_free_bit(bitmap_block->data, index_in_group); bitmap_block->dirty = true; // Release block with bitmap rc = block_put(bitmap_block); if (rc != EOK) { // Error in saving bitmap ext4_filesystem_put_block_group_ref(bg_ref); EXT4FS_DBG("error in saving bitmap \%d", rc); return rc; } uint32_t block_size = ext4_superblock_get_block_size(sb); // Update superblock free blocks count uint32_t sb_free_blocks = ext4_superblock_get_free_blocks_count(sb); sb_free_blocks++; ext4_superblock_set_free_blocks_count(sb, sb_free_blocks); // Update inode blocks count uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode); ino_blocks -= block_size / EXT4_INODE_BLOCK_SIZE; ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks); inode_ref->dirty = true; // Update block group free blocks count uint32_t free_blocks = ext4_block_group_get_free_blocks_count( bg_ref->block_group, sb); free_blocks++; ext4_block_group_set_free_blocks_count(bg_ref->block_group, sb, free_blocks); bg_ref->dirty = true; // Release block group reference rc = ext4_filesystem_put_block_group_ref(bg_ref); if (rc != EOK) { EXT4FS_DBG("error in saving bg_ref \%d", rc); return rc; } return EOK; } /** Free continuous set of blocks. * * @param inode_ref inode, where the blocks are allocated * @param first first block to release * @param count number of blocks to release */ int ext4_balloc_free_blocks(ext4_inode_ref_t *inode_ref, uint32_t first, uint32_t count) { int rc; ext4_filesystem_t *fs = inode_ref->fs; ext4_superblock_t *sb = fs->superblock; // Compute indexes uint32_t block_group_first = ext4_balloc_get_bgid_of_block(sb, first); uint32_t block_group_last = ext4_balloc_get_bgid_of_block(sb, first + count - 1); assert(block_group_first == block_group_last); // Load block group reference ext4_block_group_ref_t *bg_ref; rc = ext4_filesystem_get_block_group_ref(fs, block_group_first, &bg_ref); if (rc != EOK) { EXT4FS_DBG("error in loading bg_ref \%d", rc); return rc; } uint32_t index_in_group_first = ext4_balloc_blockaddr2_index_in_group(sb, first); // Load block with bitmap uint32_t bitmap_block_addr = ext4_block_group_get_block_bitmap( bg_ref->block_group, sb); block_t *bitmap_block; rc = block_get(&bitmap_block, fs->device, bitmap_block_addr, 0); if (rc != EOK) { EXT4FS_DBG("error in loading bitmap \%d", rc); return rc; } // Modify bitmap ext4_bitmap_free_bits(bitmap_block->data, index_in_group_first, count); bitmap_block->dirty = true; // Release block with bitmap rc = block_put(bitmap_block); if (rc != EOK) { // Error in saving bitmap ext4_filesystem_put_block_group_ref(bg_ref); EXT4FS_DBG("error in saving bitmap \%d", rc); return rc; } uint32_t block_size = ext4_superblock_get_block_size(sb); // Update superblock free blocks count uint32_t sb_free_blocks = ext4_superblock_get_free_blocks_count(sb); sb_free_blocks += count; ext4_superblock_set_free_blocks_count(sb, sb_free_blocks); // Update inode blocks count uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode); ino_blocks -= count * (block_size / EXT4_INODE_BLOCK_SIZE); ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks); inode_ref->dirty = true; // Update block group free blocks count uint32_t free_blocks = ext4_block_group_get_free_blocks_count( bg_ref->block_group, sb); free_blocks += count; ext4_block_group_set_free_blocks_count(bg_ref->block_group, sb, free_blocks); bg_ref->dirty = true; // Release block group reference rc = ext4_filesystem_put_block_group_ref(bg_ref); if (rc != EOK) { EXT4FS_DBG("error in saving bg_ref \%d", rc); return rc; } return EOK; } /** Compute first block for data in block group. * * @param sb pointer to superblock * @param bg pointer to block group * @param bgid index of block group * @return absolute block index of first block */ static uint32_t ext4_balloc_get_first_data_block_in_group( ext4_superblock_t *sb, ext4_block_group_t *bg, uint32_t bgid) { uint32_t block_group_count = ext4_superblock_get_block_group_count(sb); uint32_t inode_table_first_block = ext4_block_group_get_inode_table_first_block( bg, sb); uint16_t inode_table_item_size = ext4_superblock_get_inode_size(sb); uint32_t inodes_per_group = ext4_superblock_get_inodes_per_group(sb); uint32_t block_size = ext4_superblock_get_block_size(sb); uint32_t inode_table_bytes; if (bgid < block_group_count - 1) { inode_table_bytes = inodes_per_group * inode_table_item_size; } else { // last block group could be smaller uint32_t inodes_count_total = ext4_superblock_get_inodes_count(sb); inode_table_bytes = (inodes_count_total - ((block_group_count - 1) * inodes_per_group)) * inode_table_item_size; } uint32_t inode_table_blocks = inode_table_bytes / block_size; if (inode_table_bytes % block_size) { inode_table_blocks++; } return inode_table_first_block + inode_table_blocks; } /** Compute 'goal' for allocation algorithm. * * @param inode_ref reference to inode, to allocate block for * @return goal block number */ static uint32_t ext4_balloc_find_goal(ext4_inode_ref_t *inode_ref) { int rc; uint32_t goal = 0; ext4_superblock_t *sb = inode_ref->fs->superblock; uint64_t inode_size = ext4_inode_get_size(sb, inode_ref->inode); uint32_t block_size = ext4_superblock_get_block_size(sb); uint32_t inode_block_count = inode_size / block_size; if (inode_size % block_size != 0) { inode_block_count++; } // If inode has some blocks, get last block address + 1 if (inode_block_count > 0) { rc = ext4_filesystem_get_inode_data_block_index(inode_ref, inode_block_count - 1, &goal); if (rc != EOK) { return 0; } if (goal != 0) { goal++; return goal; } // if goal == 0, sparse file -> continue } // Identify block group of inode uint32_t inodes_per_group = ext4_superblock_get_inodes_per_group(sb); uint32_t block_group = (inode_ref->index - 1) / inodes_per_group; block_size = ext4_superblock_get_block_size(sb); // Load block group reference ext4_block_group_ref_t *bg_ref; rc = ext4_filesystem_get_block_group_ref(inode_ref->fs, block_group, &bg_ref); if (rc != EOK) { return 0; } // Compute indexes uint32_t block_group_count = ext4_superblock_get_block_group_count(sb); uint32_t inode_table_first_block = ext4_block_group_get_inode_table_first_block( bg_ref->block_group, sb); uint16_t inode_table_item_size = ext4_superblock_get_inode_size(sb); uint32_t inode_table_bytes; // Check for last block group if (block_group < block_group_count - 1) { inode_table_bytes = inodes_per_group * inode_table_item_size; } else { // last block group could be smaller uint32_t inodes_count_total = ext4_superblock_get_inodes_count(sb); inode_table_bytes = (inodes_count_total - ((block_group_count - 1) * inodes_per_group)) * inode_table_item_size; } uint32_t inode_table_blocks = inode_table_bytes / block_size; if (inode_table_bytes % block_size) { inode_table_blocks++; } goal = inode_table_first_block + inode_table_blocks; ext4_filesystem_put_block_group_ref(bg_ref); return goal; } /** Data block allocation algorithm. * * @param inode_ref inode to allocate block for * @param fblock allocated block address * @return error code */ int ext4_balloc_alloc_block( ext4_inode_ref_t *inode_ref, uint32_t *fblock) { int rc; uint32_t allocated_block = 0; uint32_t bitmap_block_addr; block_t *bitmap_block; uint32_t rel_block_idx = 0; // Find GOAL uint32_t goal = ext4_balloc_find_goal(inode_ref); if (goal == 0) { // no goal found => partition is full EXT4FS_DBG("ERRORR (goal == 0)"); return ENOSPC; } ext4_superblock_t *sb = inode_ref->fs->superblock; // Load block group number for goal and relative index uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, goal); uint32_t index_in_group = ext4_balloc_blockaddr2_index_in_group(sb, goal); // Load block group reference ext4_block_group_ref_t *bg_ref; rc = ext4_filesystem_get_block_group_ref(inode_ref->fs, block_group, &bg_ref); if (rc != EOK) { EXT4FS_DBG("initial BG ref not loaded"); return rc; } // Compute indexes uint32_t first_in_group = ext4_balloc_get_first_data_block_in_group(sb, bg_ref->block_group, block_group); uint32_t first_in_group_index = ext4_balloc_blockaddr2_index_in_group( sb, first_in_group); if (index_in_group < first_in_group_index) { index_in_group = first_in_group_index; } // Load block with bitmap bitmap_block_addr = ext4_block_group_get_block_bitmap(bg_ref->block_group, sb); rc = block_get(&bitmap_block, inode_ref->fs->device, bitmap_block_addr, 0); if (rc != EOK) { ext4_filesystem_put_block_group_ref(bg_ref); EXT4FS_DBG("initial bitmap not loaded"); return rc; } // Check if goal is free if (ext4_bitmap_is_free_bit(bitmap_block->data, index_in_group)) { ext4_bitmap_set_bit(bitmap_block->data, index_in_group); bitmap_block->dirty = true; rc = block_put(bitmap_block); if (rc != EOK) { EXT4FS_DBG("goal check: error in saving bitmap \%d", rc); ext4_filesystem_put_block_group_ref(bg_ref); return rc; } allocated_block = goal; goto success; } uint32_t blocks_in_group = ext4_superblock_get_blocks_in_group(sb, block_group); uint32_t end_idx = (index_in_group + 63) & ~63; if (end_idx > blocks_in_group) { end_idx = blocks_in_group; } // Try to find free block near to goal for (uint32_t tmp_idx = index_in_group + 1; tmp_idx < end_idx; ++tmp_idx) { if (ext4_bitmap_is_free_bit(bitmap_block->data, tmp_idx)) { ext4_bitmap_set_bit(bitmap_block->data, tmp_idx); bitmap_block->dirty = true; rc = block_put(bitmap_block); if (rc != EOK) { EXT4FS_DBG("near blocks: error in saving initial bitmap \%d", rc); return rc; } allocated_block = ext4_balloc_index_in_group2blockaddr( sb, tmp_idx, block_group); goto success; } } // Find free BYTE in bitmap rc = ext4_bitmap_find_free_byte_and_set_bit(bitmap_block->data, index_in_group, &rel_block_idx, blocks_in_group); if (rc == EOK) { bitmap_block->dirty = true; rc = block_put(bitmap_block); if (rc != EOK) { EXT4FS_DBG("free byte: error in saving initial bitmap \%d", rc); return rc; } allocated_block = ext4_balloc_index_in_group2blockaddr( sb, rel_block_idx, block_group); goto success; } // Find free bit in bitmap rc = ext4_bitmap_find_free_bit_and_set(bitmap_block->data, index_in_group, &rel_block_idx, blocks_in_group); if (rc == EOK) { bitmap_block->dirty = true; rc = block_put(bitmap_block); if (rc != EOK) { EXT4FS_DBG("free bit: error in saving initial bitmap \%d", rc); return rc; } allocated_block = ext4_balloc_index_in_group2blockaddr( sb, rel_block_idx, block_group); goto success; } // No free block found yet block_put(bitmap_block); ext4_filesystem_put_block_group_ref(bg_ref); // Try other block groups uint32_t block_group_count = ext4_superblock_get_block_group_count(sb); uint32_t bgid = (block_group + 1) % block_group_count; uint32_t count = block_group_count; while (count > 0) { rc = ext4_filesystem_get_block_group_ref(inode_ref->fs, bgid, &bg_ref); if (rc != EOK) { EXT4FS_DBG("ERROR: unable to load block group \%u", bgid); return rc; } // Load block with bitmap bitmap_block_addr = ext4_block_group_get_block_bitmap( bg_ref->block_group, sb); rc = block_get(&bitmap_block, inode_ref->fs->device, bitmap_block_addr, 0); if (rc != EOK) { ext4_filesystem_put_block_group_ref(bg_ref); EXT4FS_DBG("ERROR: unable to load bitmap block"); return rc; } // Compute indexes first_in_group = ext4_balloc_get_first_data_block_in_group( sb, bg_ref->block_group, bgid); index_in_group = ext4_balloc_blockaddr2_index_in_group(sb, first_in_group); blocks_in_group = ext4_superblock_get_blocks_in_group(sb, bgid); first_in_group_index = ext4_balloc_blockaddr2_index_in_group( sb, first_in_group); if (index_in_group < first_in_group_index) { index_in_group = first_in_group_index; } // Try to find free byte in bitmap rc = ext4_bitmap_find_free_byte_and_set_bit(bitmap_block->data, index_in_group, &rel_block_idx, blocks_in_group); if (rc == EOK) { bitmap_block->dirty = true; rc = block_put(bitmap_block); if (rc != EOK) { EXT4FS_DBG("ERROR: unable to save bitmap block"); return rc; } allocated_block = ext4_balloc_index_in_group2blockaddr( sb, rel_block_idx, bgid); goto success; } // Try to find free bit in bitmap rc = ext4_bitmap_find_free_bit_and_set(bitmap_block->data, index_in_group, &rel_block_idx, blocks_in_group); if (rc == EOK) { bitmap_block->dirty = true; rc = block_put(bitmap_block); if (rc != EOK) { EXT4FS_DBG("ERROR: unable to save bitmap block"); return rc; } allocated_block = ext4_balloc_index_in_group2blockaddr( sb, rel_block_idx, bgid); goto success; } block_put(bitmap_block); ext4_filesystem_put_block_group_ref(bg_ref); // Goto next group bgid = (bgid + 1) % block_group_count; count--; } return ENOSPC; success: ; // Empty command - because of syntax uint32_t block_size = ext4_superblock_get_block_size(sb); // Update superblock free blocks count uint32_t sb_free_blocks = ext4_superblock_get_free_blocks_count(sb); sb_free_blocks--; ext4_superblock_set_free_blocks_count(sb, sb_free_blocks); // Update inode blocks (different block size!) count uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode); ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE; ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks); inode_ref->dirty = true; // Update block group free blocks count uint32_t bg_free_blocks = ext4_block_group_get_free_blocks_count( bg_ref->block_group, sb); bg_free_blocks--; ext4_block_group_set_free_blocks_count(bg_ref->block_group, sb, bg_free_blocks); bg_ref->dirty = true; ext4_filesystem_put_block_group_ref(bg_ref); *fblock = allocated_block; return EOK; } /** Try to allocate concrete block. * * @param inode_ref inode to allocate block for * @param fblock block address to allocate * @param free output value - if target block is free * @return error code */ int ext4_balloc_try_alloc_block(ext4_inode_ref_t *inode_ref, uint32_t fblock, bool *free) { int rc = EOK; ext4_filesystem_t *fs = inode_ref->fs; ext4_superblock_t *sb = fs->superblock; // Compute indexes uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, fblock); uint32_t index_in_group = ext4_balloc_blockaddr2_index_in_group(sb, fblock); // Load block group reference ext4_block_group_ref_t *bg_ref; rc = ext4_filesystem_get_block_group_ref(fs, block_group, &bg_ref); if (rc != EOK) { EXT4FS_DBG("error in loading bg_ref \%d", rc); return rc; } // Load block with bitmap uint32_t bitmap_block_addr = ext4_block_group_get_block_bitmap( bg_ref->block_group, sb); block_t *bitmap_block; rc = block_get(&bitmap_block, fs->device, bitmap_block_addr, 0); if (rc != EOK) { EXT4FS_DBG("error in loading bitmap \%d", rc); return rc; } // Check if block is free *free = ext4_bitmap_is_free_bit(bitmap_block->data, index_in_group); // Allocate block if possible if (*free) { ext4_bitmap_set_bit(bitmap_block->data, index_in_group); bitmap_block->dirty = true; } // Release block with bitmap rc = block_put(bitmap_block); if (rc != EOK) { // Error in saving bitmap ext4_filesystem_put_block_group_ref(bg_ref); EXT4FS_DBG("error in saving bitmap \%d", rc); return rc; } // If block is not free, return if (!(*free)) { goto terminate; } uint32_t block_size = ext4_superblock_get_block_size(sb); // Update superblock free blocks count uint32_t sb_free_blocks = ext4_superblock_get_free_blocks_count(sb); sb_free_blocks--; ext4_superblock_set_free_blocks_count(sb, sb_free_blocks); // Update inode blocks count uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode); ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE; ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks); inode_ref->dirty = true; // Update block group free blocks count uint32_t free_blocks = ext4_block_group_get_free_blocks_count( bg_ref->block_group, sb); free_blocks--; ext4_block_group_set_free_blocks_count(bg_ref->block_group, sb, free_blocks); bg_ref->dirty = true; terminate: rc = ext4_filesystem_put_block_group_ref(bg_ref); if (rc != EOK) { EXT4FS_DBG("error in saving bg_ref \%d", rc); return rc; } return rc; } /** * @} */