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diff --git a/src/ext4_balloc.c b/src/ext4_balloc.c
new file mode 100644
index 0000000..2980e26
--- /dev/null
+++ b/src/ext4_balloc.c
@@ -0,0 +1,654 @@
+/*
+ * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
+ *
+ * HelenOS:
+ * Copyright (c) 2012 Martin Sucha
+ * 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 lwext4
+ * @{
+ */
+/**
+ * @file  ext4_balloc.c
+ * @brief Physical block allocator.
+ */
+
+#include "ext4_config.h"
+#include "ext4_balloc.h"
+#include "ext4_super.h"
+#include "ext4_crc32.h"
+#include "ext4_block_group.h"
+#include "ext4_fs.h"
+#include "ext4_bitmap.h"
+#include "ext4_inode.h"
+
+/**@brief Compute number of block group from block address.
+ * @param sb superblock pointer.
+ * @param baddr Absolute address of block.
+ * @return Block group index
+ */
+uint32_t ext4_balloc_get_bgid_of_block(struct ext4_sblock *s,
+				       uint64_t baddr)
+{
+	if (ext4_get32(s, first_data_block) && baddr)
+		baddr--;
+
+	return (uint32_t)(baddr / ext4_get32(s, blocks_per_group));
+}
+
+/**@brief Compute the starting block address of a block group
+ * @param sb   superblock pointer.
+ * @param bgid block group index
+ * @return Block address
+ */
+uint64_t ext4_balloc_get_block_of_bgid(struct ext4_sblock *s,
+				       uint32_t bgid)
+{
+	uint64_t baddr = 0;
+	if (ext4_get32(s, first_data_block))
+		baddr++;
+
+	baddr += bgid * ext4_get32(s, blocks_per_group);
+	return baddr;
+}
+
+#if CONFIG_META_CSUM_ENABLE
+static uint32_t ext4_balloc_bitmap_csum(struct ext4_sblock *sb,
+					void *bitmap)
+{
+	uint32_t checksum = 0;
+	if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
+		uint32_t blocks_per_group = ext4_get32(sb, blocks_per_group);
+
+		/* First calculate crc32 checksum against fs uuid */
+		checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
+				sizeof(sb->uuid));
+		/* Then calculate crc32 checksum against block_group_desc */
+		checksum = ext4_crc32c(checksum, bitmap, blocks_per_group / 8);
+	}
+	return checksum;
+}
+#else
+#define ext4_balloc_bitmap_csum(...) 0
+#endif
+
+void ext4_balloc_set_bitmap_csum(struct ext4_sblock *sb,
+				 struct ext4_bgroup *bg,
+				 void *bitmap __unused)
+{
+	int desc_size = ext4_sb_get_desc_size(sb);
+	uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
+	uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
+		 hi_checksum = to_le16(checksum >> 16);
+
+	if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
+		return;
+
+	/* See if we need to assign a 32bit checksum */
+	bg->block_bitmap_csum_lo = lo_checksum;
+	if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
+		bg->block_bitmap_csum_hi = hi_checksum;
+
+}
+
+#if CONFIG_META_CSUM_ENABLE
+static bool
+ext4_balloc_verify_bitmap_csum(struct ext4_sblock *sb,
+			       struct ext4_bgroup *bg,
+			       void *bitmap __unused)
+{
+	int desc_size = ext4_sb_get_desc_size(sb);
+	uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
+	uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
+		 hi_checksum = to_le16(checksum >> 16);
+
+	if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
+		return true;
+
+	if (bg->block_bitmap_csum_lo != lo_checksum)
+		return false;
+
+	if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
+		if (bg->block_bitmap_csum_hi != hi_checksum)
+			return false;
+
+	return true;
+}
+#else
+#define ext4_balloc_verify_bitmap_csum(...) true
+#endif
+
+int ext4_balloc_free_block(struct ext4_inode_ref *inode_ref, ext4_fsblk_t baddr)
+{
+	struct ext4_fs *fs = inode_ref->fs;
+	struct ext4_sblock *sb = &fs->sb;
+
+	uint32_t bg_id = ext4_balloc_get_bgid_of_block(sb, baddr);
+	uint32_t index_in_group = ext4_fs_addr_to_idx_bg(sb, baddr);
+
+	/* Load block group reference */
+	struct ext4_block_group_ref bg_ref;
+	int rc = ext4_fs_get_block_group_ref(fs, bg_id, &bg_ref);
+	if (rc != EOK)
+		return rc;
+
+	struct ext4_bgroup *bg = bg_ref.block_group;
+
+	/* Load block with bitmap */
+	ext4_fsblk_t bitmap_block_addr =
+	    ext4_bg_get_block_bitmap(bg, sb);
+
+	struct ext4_block bitmap_block;
+
+	rc = ext4_trans_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
+	if (rc != EOK) {
+		ext4_fs_put_block_group_ref(&bg_ref);
+		return rc;
+	}
+
+	if (!ext4_balloc_verify_bitmap_csum(sb, bg, bitmap_block.data)) {
+		ext4_dbg(DEBUG_BALLOC,
+			DBG_WARN "Bitmap checksum failed."
+			"Group: %" PRIu32"\n",
+			bg_ref.index);
+	}
+
+	/* Modify bitmap */
+	ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
+	ext4_balloc_set_bitmap_csum(sb, bg, bitmap_block.data);
+	ext4_trans_set_block_dirty(bitmap_block.buf);
+
+	/* Release block with bitmap */
+	rc = ext4_block_set(fs->bdev, &bitmap_block);
+	if (rc != EOK) {
+		/* Error in saving bitmap */
+		ext4_fs_put_block_group_ref(&bg_ref);
+		return rc;
+	}
+
+	uint32_t block_size = ext4_sb_get_block_size(sb);
+
+	/* Update superblock free blocks count */
+	uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
+	sb_free_blocks++;
+	ext4_sb_set_free_blocks_cnt(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_bg_get_free_blocks_count(bg, sb);
+	free_blocks++;
+	ext4_bg_set_free_blocks_count(bg, sb, free_blocks);
+
+	bg_ref.dirty = true;
+
+	rc = ext4_trans_try_revoke_block(fs->bdev, baddr);
+	if (rc != EOK) {
+		bg_ref.dirty = false;
+		ext4_fs_put_block_group_ref(&bg_ref);
+		return rc;
+	}
+	ext4_bcache_invalidate_lba(fs->bdev->bc, baddr, 1);
+	/* Release block group reference */
+	return ext4_fs_put_block_group_ref(&bg_ref);
+}
+
+int ext4_balloc_free_blocks(struct ext4_inode_ref *inode_ref,
+			    ext4_fsblk_t first, uint32_t count)
+{
+	int rc = EOK;
+	struct ext4_fs *fs = inode_ref->fs;
+	struct ext4_sblock *sb = &fs->sb;
+
+	/* Compute indexes */
+	uint32_t bg_first = ext4_balloc_get_bgid_of_block(sb, first);
+
+	/* Compute indexes */
+	uint32_t bg_last = ext4_balloc_get_bgid_of_block(sb, first + count - 1);
+
+	if (!ext4_sb_feature_incom(sb, EXT4_FINCOM_FLEX_BG)) {
+		/*It is not possible without flex_bg that blocks are continuous
+		 * and and last block belongs to other bg.*/
+		if (bg_last != bg_first) {
+			ext4_dbg(DEBUG_BALLOC, DBG_WARN "FLEX_BG: disabled & "
+				"bg_last: %"PRIu32" bg_first: %"PRIu32"\n",
+				bg_last, bg_first);
+		}
+	}
+
+	/* Load block group reference */
+	struct ext4_block_group_ref bg_ref;
+	while (bg_first <= bg_last) {
+
+		rc = ext4_fs_get_block_group_ref(fs, bg_first, &bg_ref);
+		if (rc != EOK)
+			return rc;
+
+		struct ext4_bgroup *bg = bg_ref.block_group;
+
+		uint32_t idx_in_bg_first;
+		idx_in_bg_first = ext4_fs_addr_to_idx_bg(sb, first);
+
+		/* Load block with bitmap */
+		ext4_fsblk_t bitmap_blk = ext4_bg_get_block_bitmap(bg, sb);
+
+		struct ext4_block blk;
+		rc = ext4_trans_block_get(fs->bdev, &blk, bitmap_blk);
+		if (rc != EOK) {
+			ext4_fs_put_block_group_ref(&bg_ref);
+			return rc;
+		}
+
+		if (!ext4_balloc_verify_bitmap_csum(sb, bg, blk.data)) {
+			ext4_dbg(DEBUG_BALLOC,
+				DBG_WARN "Bitmap checksum failed."
+				"Group: %" PRIu32"\n",
+				bg_ref.index);
+		}
+		uint32_t free_cnt;
+		free_cnt = ext4_sb_get_block_size(sb) * 8 - idx_in_bg_first;
+
+		/*If last block, free only count blocks*/
+		free_cnt = count > free_cnt ? free_cnt : count;
+
+		/* Modify bitmap */
+		ext4_bmap_bits_free(blk.data, idx_in_bg_first, free_cnt);
+		ext4_balloc_set_bitmap_csum(sb, bg, blk.data);
+		ext4_trans_set_block_dirty(blk.buf);
+
+		count -= free_cnt;
+		first += free_cnt;
+
+		/* Release block with bitmap */
+		rc = ext4_block_set(fs->bdev, &blk);
+		if (rc != EOK) {
+			ext4_fs_put_block_group_ref(&bg_ref);
+			return rc;
+		}
+
+		uint32_t block_size = ext4_sb_get_block_size(sb);
+
+		/* Update superblock free blocks count */
+		uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
+		sb_free_blocks += free_cnt;
+		ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
+
+		/* Update inode blocks count */
+		uint64_t ino_blocks;
+		ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
+		ino_blocks -= free_cnt * (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;
+		free_blocks = ext4_bg_get_free_blocks_count(bg, sb);
+		free_blocks += free_cnt;
+		ext4_bg_set_free_blocks_count(bg, sb, free_blocks);
+		bg_ref.dirty = true;
+
+		/* Release block group reference */
+		rc = ext4_fs_put_block_group_ref(&bg_ref);
+		if (rc != EOK)
+			break;
+
+		bg_first++;
+	}
+
+	uint32_t i;
+	for (i = 0;i < count;i++) {
+		rc = ext4_trans_try_revoke_block(fs->bdev, first + i);
+		if (rc != EOK)
+			return rc;
+
+	}
+
+	ext4_bcache_invalidate_lba(fs->bdev->bc, first, count);
+	/*All blocks should be released*/
+	ext4_assert(count == 0);
+	return rc;
+}
+
+int ext4_balloc_alloc_block(struct ext4_inode_ref *inode_ref,
+			    ext4_fsblk_t goal,
+			    ext4_fsblk_t *fblock)
+{
+	ext4_fsblk_t alloc = 0;
+	ext4_fsblk_t bmp_blk_adr;
+	uint32_t rel_blk_idx = 0;
+	uint64_t free_blocks;
+	int r;
+	struct ext4_sblock *sb = &inode_ref->fs->sb;
+
+	/* Load block group number for goal and relative index */
+	uint32_t bg_id = ext4_balloc_get_bgid_of_block(sb, goal);
+	uint32_t idx_in_bg = ext4_fs_addr_to_idx_bg(sb, goal);
+
+	struct ext4_block b;
+	struct ext4_block_group_ref bg_ref;
+
+	/* Load block group reference */
+	r = ext4_fs_get_block_group_ref(inode_ref->fs, bg_id, &bg_ref);
+	if (r != EOK)
+		return r;
+
+	struct ext4_bgroup *bg = bg_ref.block_group;
+
+	free_blocks = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
+	if (free_blocks == 0) {
+		/* This group has no free blocks */
+		goto goal_failed;
+	}
+
+	/* Compute indexes */
+	ext4_fsblk_t first_in_bg;
+	first_in_bg = ext4_balloc_get_block_of_bgid(sb, bg_ref.index);
+
+	uint32_t first_in_bg_index;
+	first_in_bg_index = ext4_fs_addr_to_idx_bg(sb, first_in_bg);
+
+	if (idx_in_bg < first_in_bg_index)
+		idx_in_bg = first_in_bg_index;
+
+	/* Load block with bitmap */
+	bmp_blk_adr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
+
+	r = ext4_trans_block_get(inode_ref->fs->bdev, &b, bmp_blk_adr);
+	if (r != EOK) {
+		ext4_fs_put_block_group_ref(&bg_ref);
+		return r;
+	}
+
+	if (!ext4_balloc_verify_bitmap_csum(sb, bg, b.data)) {
+		ext4_dbg(DEBUG_BALLOC,
+			DBG_WARN "Bitmap checksum failed."
+			"Group: %" PRIu32"\n",
+			bg_ref.index);
+	}
+
+	/* Check if goal is free */
+	if (ext4_bmap_is_bit_clr(b.data, idx_in_bg)) {
+		ext4_bmap_bit_set(b.data, idx_in_bg);
+		ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
+					    b.data);
+		ext4_trans_set_block_dirty(b.buf);
+		r = ext4_block_set(inode_ref->fs->bdev, &b);
+		if (r != EOK) {
+			ext4_fs_put_block_group_ref(&bg_ref);
+			return r;
+		}
+
+		alloc = ext4_fs_bg_idx_to_addr(sb, idx_in_bg, bg_id);
+		goto success;
+	}
+
+	uint32_t blk_in_bg = ext4_blocks_in_group_cnt(sb, bg_id);
+
+	uint32_t end_idx = (idx_in_bg + 63) & ~63;
+	if (end_idx > blk_in_bg)
+		end_idx = blk_in_bg;
+
+	/* Try to find free block near to goal */
+	uint32_t tmp_idx;
+	for (tmp_idx = idx_in_bg + 1; tmp_idx < end_idx; ++tmp_idx) {
+		if (ext4_bmap_is_bit_clr(b.data, tmp_idx)) {
+			ext4_bmap_bit_set(b.data, tmp_idx);
+
+			ext4_balloc_set_bitmap_csum(sb, bg, b.data);
+			ext4_trans_set_block_dirty(b.buf);
+			r = ext4_block_set(inode_ref->fs->bdev, &b);
+			if (r != EOK)
+				return r;
+
+			alloc = ext4_fs_bg_idx_to_addr(sb, tmp_idx, bg_id);
+			goto success;
+		}
+	}
+
+	/* Find free bit in bitmap */
+	r = ext4_bmap_bit_find_clr(b.data, idx_in_bg, blk_in_bg, &rel_blk_idx);
+	if (r == EOK) {
+		ext4_bmap_bit_set(b.data, rel_blk_idx);
+		ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group, b.data);
+		ext4_trans_set_block_dirty(b.buf);
+		r = ext4_block_set(inode_ref->fs->bdev, &b);
+		if (r != EOK)
+			return r;
+
+		alloc = ext4_fs_bg_idx_to_addr(sb, rel_blk_idx, bg_id);
+		goto success;
+	}
+
+	/* No free block found yet */
+	r = ext4_block_set(inode_ref->fs->bdev, &b);
+	if (r != EOK) {
+		ext4_fs_put_block_group_ref(&bg_ref);
+		return r;
+	}
+
+goal_failed:
+
+	r = ext4_fs_put_block_group_ref(&bg_ref);
+	if (r != EOK)
+		return r;
+
+	/* Try other block groups */
+	uint32_t block_group_count = ext4_block_group_cnt(sb);
+	uint32_t bgid = (bg_id + 1) % block_group_count;
+	uint32_t count = block_group_count;
+
+	while (count > 0) {
+		r = ext4_fs_get_block_group_ref(inode_ref->fs, bgid, &bg_ref);
+		if (r != EOK)
+			return r;
+
+		struct ext4_bgroup *bg = bg_ref.block_group;
+		free_blocks = ext4_bg_get_free_blocks_count(bg, sb);
+		if (free_blocks == 0) {
+			/* This group has no free blocks */
+			goto next_group;
+		}
+
+		/* Load block with bitmap */
+		bmp_blk_adr = ext4_bg_get_block_bitmap(bg, sb);
+		r = ext4_trans_block_get(inode_ref->fs->bdev, &b, bmp_blk_adr);
+		if (r != EOK) {
+			ext4_fs_put_block_group_ref(&bg_ref);
+			return r;
+		}
+
+		if (!ext4_balloc_verify_bitmap_csum(sb, bg, b.data)) {
+			ext4_dbg(DEBUG_BALLOC,
+				DBG_WARN "Bitmap checksum failed."
+				"Group: %" PRIu32"\n",
+				bg_ref.index);
+		}
+
+		/* Compute indexes */
+		first_in_bg = ext4_balloc_get_block_of_bgid(sb, bgid);
+		idx_in_bg = ext4_fs_addr_to_idx_bg(sb, first_in_bg);
+		blk_in_bg = ext4_blocks_in_group_cnt(sb, bgid);
+		first_in_bg_index = ext4_fs_addr_to_idx_bg(sb, first_in_bg);
+
+		if (idx_in_bg < first_in_bg_index)
+			idx_in_bg = first_in_bg_index;
+
+		r = ext4_bmap_bit_find_clr(b.data, idx_in_bg, blk_in_bg,
+				&rel_blk_idx);
+		if (r == EOK) {
+			ext4_bmap_bit_set(b.data, rel_blk_idx);
+			ext4_balloc_set_bitmap_csum(sb, bg, b.data);
+			ext4_trans_set_block_dirty(b.buf);
+			r = ext4_block_set(inode_ref->fs->bdev, &b);
+			if (r != EOK) {
+				ext4_fs_put_block_group_ref(&bg_ref);
+				return r;
+			}
+
+			alloc = ext4_fs_bg_idx_to_addr(sb, rel_blk_idx, bgid);
+			goto success;
+		}
+
+		r = ext4_block_set(inode_ref->fs->bdev, &b);
+		if (r != EOK) {
+			ext4_fs_put_block_group_ref(&bg_ref);
+			return r;
+		}
+
+	next_group:
+		r = ext4_fs_put_block_group_ref(&bg_ref);
+		if (r != EOK) {
+			return r;
+		}
+
+		/* Goto next group */
+		bgid = (bgid + 1) % block_group_count;
+		count--;
+	}
+
+	return ENOSPC;
+
+success:
+    /* Empty command - because of syntax */
+    ;
+
+	uint32_t block_size = ext4_sb_get_block_size(sb);
+
+	/* Update superblock free blocks count */
+	uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
+	sb_free_blocks--;
+	ext4_sb_set_free_blocks_cnt(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 fb_cnt = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
+	fb_cnt--;
+	ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, fb_cnt);
+
+	bg_ref.dirty = true;
+	r = ext4_fs_put_block_group_ref(&bg_ref);
+
+	*fblock = alloc;
+	return r;
+}
+
+int ext4_balloc_try_alloc_block(struct ext4_inode_ref *inode_ref,
+				ext4_fsblk_t baddr, bool *free)
+{
+	int rc;
+
+	struct ext4_fs *fs = inode_ref->fs;
+	struct ext4_sblock *sb = &fs->sb;
+
+	/* Compute indexes */
+	uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
+	uint32_t index_in_group = ext4_fs_addr_to_idx_bg(sb, baddr);
+
+	/* Load block group reference */
+	struct ext4_block_group_ref bg_ref;
+	rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
+	if (rc != EOK)
+		return rc;
+
+	/* Load block with bitmap */
+	ext4_fsblk_t bmp_blk_addr;
+	bmp_blk_addr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
+
+	struct ext4_block b;
+	rc = ext4_trans_block_get(fs->bdev, &b, bmp_blk_addr);
+	if (rc != EOK) {
+		ext4_fs_put_block_group_ref(&bg_ref);
+		return rc;
+	}
+
+	if (!ext4_balloc_verify_bitmap_csum(sb, bg_ref.block_group, b.data)) {
+		ext4_dbg(DEBUG_BALLOC,
+			DBG_WARN "Bitmap checksum failed."
+			"Group: %" PRIu32"\n",
+			bg_ref.index);
+	}
+
+	/* Check if block is free */
+	*free = ext4_bmap_is_bit_clr(b.data, index_in_group);
+
+	/* Allocate block if possible */
+	if (*free) {
+		ext4_bmap_bit_set(b.data, index_in_group);
+		ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group, b.data);
+		ext4_trans_set_block_dirty(b.buf);
+	}
+
+	/* Release block with bitmap */
+	rc = ext4_block_set(fs->bdev, &b);
+	if (rc != EOK) {
+		/* Error in saving bitmap */
+		ext4_fs_put_block_group_ref(&bg_ref);
+		return rc;
+	}
+
+	/* If block is not free, return */
+	if (!(*free))
+		goto terminate;
+
+	uint32_t block_size = ext4_sb_get_block_size(sb);
+
+	/* Update superblock free blocks count */
+	uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
+	sb_free_blocks--;
+	ext4_sb_set_free_blocks_cnt(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 fb_cnt = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
+	fb_cnt--;
+	ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, fb_cnt);
+
+	bg_ref.dirty = true;
+
+terminate:
+	return ext4_fs_put_block_group_ref(&bg_ref);
+}
+
+/**
+ * @}
+ */