diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 7669d154c05e..e57054bdc5fd 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4111,10 +4111,10 @@ insert_hole:
  *
  * Need to be called with
  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
- * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
+ * (ie, flags is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
  *
  * return > 0, number of blocks already mapped/allocated
- *          if create == 0 and these are pre-allocated blocks
+ *          if flags doesn't contain EXT4_GET_BLOCKS_CREATE and these are pre-allocated blocks
  *          	buffer head is unmapped
  *          otherwise blocks are mapped
  *
@@ -4218,7 +4218,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 
 	/*
 	 * requested block isn't allocated yet;
-	 * we couldn't try to create block if create flag is zero
+	 * we couldn't try to create block if flags doesn't contain EXT4_GET_BLOCKS_CREATE
 	 */
 	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
 		ext4_lblk_t len;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 2ccf3b5e3a7c..537803250ca9 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -465,9 +465,10 @@ static void ext4_map_blocks_es_recheck(handle_t *handle,
  * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
  * based files
  *
- * On success, it returns the number of blocks being mapped or allocated.  if
- * create==0 and the blocks are pre-allocated and unwritten, the resulting @map
- * is marked as unwritten. If the create == 1, it will mark @map as mapped.
+ * On success, it returns the number of blocks being mapped or allocated.
+ * If flags doesn't contain EXT4_GET_BLOCKS_CREATE the blocks are
+ * pre-allocated and unwritten, the resulting @map is marked as unwritten.
+ * If the flags contain EXT4_GET_BLOCKS_CREATE, it will mark @map as mapped.
  *
  * It returns 0 if plain look up failed (blocks have not been allocated), in
  * that case, @map is returned as unmapped but we still do fill map->m_len to
@@ -589,8 +590,7 @@ found:
 	 * Returns if the blocks have already allocated
 	 *
 	 * Note that if blocks have been preallocated
-	 * ext4_ext_get_block() returns the create = 0
-	 * with buffer head unmapped.
+	 * ext4_ext_map_blocks() returns with buffer head unmapped
 	 */
 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
 		/*
diff --git a/fs/ext4/mballoc-test.c b/fs/ext4/mballoc-test.c
index f94901fd3835..044ca5238f41 100644
--- a/fs/ext4/mballoc-test.c
+++ b/fs/ext4/mballoc-test.c
@@ -5,6 +5,7 @@
 
 #include <kunit/test.h>
 #include <kunit/static_stub.h>
+#include <linux/random.h>
 
 #include "ext4.h"
 
@@ -20,41 +21,135 @@ struct mbt_ctx {
 };
 
 struct mbt_ext4_super_block {
-	struct super_block sb;
+	struct ext4_super_block es;
+	struct ext4_sb_info sbi;
 	struct mbt_ctx mbt_ctx;
 };
 
-#define MBT_CTX(_sb) (&(container_of((_sb), struct mbt_ext4_super_block, sb)->mbt_ctx))
+#define MBT_SB(_sb) (container_of((_sb)->s_fs_info, struct mbt_ext4_super_block, sbi))
+#define MBT_CTX(_sb) (&MBT_SB(_sb)->mbt_ctx)
 #define MBT_GRP_CTX(_sb, _group) (&MBT_CTX(_sb)->grp_ctx[_group])
 
+static const struct super_operations mbt_sops = {
+};
+
+static void mbt_kill_sb(struct super_block *sb)
+{
+	generic_shutdown_super(sb);
+}
+
+static struct file_system_type mbt_fs_type = {
+	.name			= "mballoc test",
+	.kill_sb		= mbt_kill_sb,
+};
+
+static int mbt_mb_init(struct super_block *sb)
+{
+	ext4_fsblk_t block;
+	int ret;
+
+	/* needed by ext4_mb_init->bdev_nonrot(sb->s_bdev) */
+	sb->s_bdev = kzalloc(sizeof(*sb->s_bdev), GFP_KERNEL);
+	if (sb->s_bdev == NULL)
+		return -ENOMEM;
+
+	sb->s_bdev->bd_queue = kzalloc(sizeof(struct request_queue), GFP_KERNEL);
+	if (sb->s_bdev->bd_queue == NULL) {
+		kfree(sb->s_bdev);
+		return -ENOMEM;
+	}
+
+	/*
+	 * needed by ext4_mb_init->ext4_mb_init_backend-> sbi->s_buddy_cache =
+	 * new_inode(sb);
+	 */
+	INIT_LIST_HEAD(&sb->s_inodes);
+	sb->s_op = &mbt_sops;
+
+	ret = ext4_mb_init(sb);
+	if (ret != 0)
+		goto err_out;
+
+	block = ext4_count_free_clusters(sb);
+	ret = percpu_counter_init(&EXT4_SB(sb)->s_freeclusters_counter, block,
+				  GFP_KERNEL);
+	if (ret != 0)
+		goto err_mb_release;
+
+	ret = percpu_counter_init(&EXT4_SB(sb)->s_dirtyclusters_counter, 0,
+				  GFP_KERNEL);
+	if (ret != 0)
+		goto err_freeclusters;
+
+	return 0;
+
+err_freeclusters:
+	percpu_counter_destroy(&EXT4_SB(sb)->s_freeclusters_counter);
+err_mb_release:
+	ext4_mb_release(sb);
+err_out:
+	kfree(sb->s_bdev->bd_queue);
+	kfree(sb->s_bdev);
+	return ret;
+}
+
+static void mbt_mb_release(struct super_block *sb)
+{
+	percpu_counter_destroy(&EXT4_SB(sb)->s_dirtyclusters_counter);
+	percpu_counter_destroy(&EXT4_SB(sb)->s_freeclusters_counter);
+	ext4_mb_release(sb);
+	kfree(sb->s_bdev->bd_queue);
+	kfree(sb->s_bdev);
+}
+
+static int mbt_set(struct super_block *sb, void *data)
+{
+	return 0;
+}
+
 static struct super_block *mbt_ext4_alloc_super_block(void)
 {
-	struct ext4_super_block *es = kzalloc(sizeof(*es), GFP_KERNEL);
-	struct ext4_sb_info *sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	struct mbt_ext4_super_block *fsb = kzalloc(sizeof(*fsb), GFP_KERNEL);
+	struct mbt_ext4_super_block *fsb;
+	struct super_block *sb;
+	struct ext4_sb_info *sbi;
 
-	if (fsb == NULL || sbi == NULL || es == NULL)
+	fsb = kzalloc(sizeof(*fsb), GFP_KERNEL);
+	if (fsb == NULL)
+		return NULL;
+
+	sb = sget(&mbt_fs_type, NULL, mbt_set, 0, NULL);
+	if (IS_ERR(sb))
 		goto out;
 
-	sbi->s_es = es;
-	fsb->sb.s_fs_info = sbi;
-	return &fsb->sb;
+	sbi = &fsb->sbi;
 
+	sbi->s_blockgroup_lock =
+		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
+	if (!sbi->s_blockgroup_lock)
+		goto out_deactivate;
+
+	bgl_lock_init(sbi->s_blockgroup_lock);
+
+	sbi->s_es = &fsb->es;
+	sb->s_fs_info = sbi;
+
+	up_write(&sb->s_umount);
+	return sb;
+
+out_deactivate:
+	deactivate_locked_super(sb);
 out:
 	kfree(fsb);
-	kfree(sbi);
-	kfree(es);
 	return NULL;
 }
 
 static void mbt_ext4_free_super_block(struct super_block *sb)
 {
-	struct mbt_ext4_super_block *fsb =
-		container_of(sb, struct mbt_ext4_super_block, sb);
+	struct mbt_ext4_super_block *fsb = MBT_SB(sb);
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 
-	kfree(sbi->s_es);
-	kfree(sbi);
+	kfree(sbi->s_blockgroup_lock);
+	deactivate_super(sb);
 	kfree(fsb);
 }
 
@@ -82,6 +177,9 @@ static void mbt_init_sb_layout(struct super_block *sb,
 	sbi->s_clusters_per_group = layout->blocks_per_group >>
 				    layout->cluster_bits;
 	sbi->s_desc_size = layout->desc_size;
+	sbi->s_desc_per_block_bits =
+		sb->s_blocksize_bits - (fls(layout->desc_size) - 1);
+	sbi->s_desc_per_block = 1 << sbi->s_desc_per_block_bits;
 
 	es->s_first_data_block = cpu_to_le32(0);
 	es->s_blocks_count_lo = cpu_to_le32(layout->blocks_per_group *
@@ -91,9 +189,13 @@ static void mbt_init_sb_layout(struct super_block *sb,
 static int mbt_grp_ctx_init(struct super_block *sb,
 			    struct mbt_grp_ctx *grp_ctx)
 {
+	ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
+
 	grp_ctx->bitmap_bh.b_data = kzalloc(EXT4_BLOCK_SIZE(sb), GFP_KERNEL);
 	if (grp_ctx->bitmap_bh.b_data == NULL)
 		return -ENOMEM;
+	mb_set_bits(grp_ctx->bitmap_bh.b_data, max, sb->s_blocksize * 8 - max);
+	ext4_free_group_clusters_set(sb, &grp_ctx->desc, max);
 
 	return 0;
 }
@@ -112,6 +214,13 @@ static void mbt_ctx_mark_used(struct super_block *sb, ext4_group_t group,
 	mb_set_bits(grp_ctx->bitmap_bh.b_data, start, len);
 }
 
+static void *mbt_ctx_bitmap(struct super_block *sb, ext4_group_t group)
+{
+	struct mbt_grp_ctx *grp_ctx = MBT_GRP_CTX(sb, group);
+
+	return grp_ctx->bitmap_bh.b_data;
+}
+
 /* called after mbt_init_sb_layout */
 static int mbt_ctx_init(struct super_block *sb)
 {
@@ -133,6 +242,8 @@ static int mbt_ctx_init(struct super_block *sb)
 	 * block which will fail ext4_sb_block_valid check.
 	 */
 	mb_set_bits(ctx->grp_ctx[0].bitmap_bh.b_data, 0, 1);
+	ext4_free_group_clusters_set(sb, &ctx->grp_ctx[0].desc,
+				     EXT4_CLUSTERS_PER_GROUP(sb) - 1);
 
 	return 0;
 out:
@@ -167,6 +278,13 @@ static int ext4_wait_block_bitmap_stub(struct super_block *sb,
 				       ext4_group_t block_group,
 				       struct buffer_head *bh)
 {
+	/*
+	 * real ext4_wait_block_bitmap will set these flags and
+	 * functions like ext4_mb_init_cache will verify the flags.
+	 */
+	set_buffer_uptodate(bh);
+	set_bitmap_uptodate(bh);
+	set_buffer_verified(bh);
 	return 0;
 }
 
@@ -232,6 +350,14 @@ static int mbt_kunit_init(struct kunit *test)
 	kunit_activate_static_stub(test,
 				   ext4_mb_mark_context,
 				   ext4_mb_mark_context_stub);
+
+	/* stub function will be called in mbt_mb_init->ext4_mb_init */
+	if (mbt_mb_init(sb) != 0) {
+		mbt_ctx_release(sb);
+		mbt_ext4_free_super_block(sb);
+		return -ENOMEM;
+	}
+
 	return 0;
 }
 
@@ -239,6 +365,7 @@ static void mbt_kunit_exit(struct kunit *test)
 {
 	struct super_block *sb = (struct super_block *)test->priv;
 
+	mbt_mb_release(sb);
 	mbt_ctx_release(sb);
 	mbt_ext4_free_super_block(sb);
 }
@@ -246,14 +373,19 @@ static void mbt_kunit_exit(struct kunit *test)
 static void test_new_blocks_simple(struct kunit *test)
 {
 	struct super_block *sb = (struct super_block *)test->priv;
-	struct inode inode = { .i_sb = sb, };
+	struct inode *inode;
 	struct ext4_allocation_request ar;
 	ext4_group_t i, goal_group = TEST_GOAL_GROUP;
 	int err = 0;
 	ext4_fsblk_t found;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 
-	ar.inode = &inode;
+	inode = kunit_kzalloc(test, sizeof(*inode), GFP_KERNEL);
+	if (!inode)
+		return;
+
+	inode->i_sb = sb;
+	ar.inode = inode;
 
 	/* get block at goal */
 	ar.goal = ext4_group_first_block_no(sb, goal_group);
@@ -297,6 +429,436 @@ static void test_new_blocks_simple(struct kunit *test)
 		"unexpectedly get block when no block is available");
 }
 
+#define TEST_RANGE_COUNT 8
+
+struct test_range {
+	ext4_grpblk_t start;
+	ext4_grpblk_t len;
+};
+
+static void
+mbt_generate_test_ranges(struct super_block *sb, struct test_range *ranges,
+			 int count)
+{
+	ext4_grpblk_t start, len, max;
+	int i;
+
+	max = EXT4_CLUSTERS_PER_GROUP(sb) / count;
+	for (i = 0; i < count; i++) {
+		start = get_random_u32() % max;
+		len = get_random_u32() % max;
+		len = min(len, max - start);
+
+		ranges[i].start = start + i * max;
+		ranges[i].len = len;
+	}
+}
+
+static void
+validate_free_blocks_simple(struct kunit *test, struct super_block *sb,
+			    ext4_group_t goal_group, ext4_grpblk_t start,
+			    ext4_grpblk_t len)
+{
+	void *bitmap;
+	ext4_grpblk_t bit, max = EXT4_CLUSTERS_PER_GROUP(sb);
+	ext4_group_t i;
+
+	for (i = 0; i < ext4_get_groups_count(sb); i++) {
+		if (i == goal_group)
+			continue;
+
+		bitmap = mbt_ctx_bitmap(sb, i);
+		bit = mb_find_next_zero_bit(bitmap, max, 0);
+		KUNIT_ASSERT_EQ_MSG(test, bit, max,
+				    "free block on unexpected group %d", i);
+	}
+
+	bitmap = mbt_ctx_bitmap(sb, goal_group);
+	bit = mb_find_next_zero_bit(bitmap, max, 0);
+	KUNIT_ASSERT_EQ(test, bit, start);
+
+	bit = mb_find_next_bit(bitmap, max, bit + 1);
+	KUNIT_ASSERT_EQ(test, bit, start + len);
+}
+
+static void
+test_free_blocks_simple_range(struct kunit *test, ext4_group_t goal_group,
+			      ext4_grpblk_t start, ext4_grpblk_t len)
+{
+	struct super_block *sb = (struct super_block *)test->priv;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct inode *inode;
+	ext4_fsblk_t block;
+
+	inode = kunit_kzalloc(test, sizeof(*inode), GFP_KERNEL);
+	if (!inode)
+		return;
+	inode->i_sb = sb;
+
+	if (len == 0)
+		return;
+
+	block = ext4_group_first_block_no(sb, goal_group) +
+		EXT4_C2B(sbi, start);
+	ext4_free_blocks_simple(inode, block, len);
+	validate_free_blocks_simple(test, sb, goal_group, start, len);
+	mbt_ctx_mark_used(sb, goal_group, 0, EXT4_CLUSTERS_PER_GROUP(sb));
+}
+
+static void test_free_blocks_simple(struct kunit *test)
+{
+	struct super_block *sb = (struct super_block *)test->priv;
+	ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
+	ext4_group_t i;
+	struct test_range ranges[TEST_RANGE_COUNT];
+
+	for (i = 0; i < ext4_get_groups_count(sb); i++)
+		mbt_ctx_mark_used(sb, i, 0, max);
+
+	mbt_generate_test_ranges(sb, ranges, TEST_RANGE_COUNT);
+	for (i = 0; i < TEST_RANGE_COUNT; i++)
+		test_free_blocks_simple_range(test, TEST_GOAL_GROUP,
+			ranges[i].start, ranges[i].len);
+}
+
+static void
+test_mark_diskspace_used_range(struct kunit *test,
+			       struct ext4_allocation_context *ac,
+			       ext4_grpblk_t start,
+			       ext4_grpblk_t len)
+{
+	struct super_block *sb = (struct super_block *)test->priv;
+	int ret;
+	void *bitmap;
+	ext4_grpblk_t i, max;
+
+	/* ext4_mb_mark_diskspace_used will BUG if len is 0 */
+	if (len == 0)
+		return;
+
+	ac->ac_b_ex.fe_group = TEST_GOAL_GROUP;
+	ac->ac_b_ex.fe_start = start;
+	ac->ac_b_ex.fe_len = len;
+
+	bitmap = mbt_ctx_bitmap(sb, TEST_GOAL_GROUP);
+	memset(bitmap, 0, sb->s_blocksize);
+	ret = ext4_mb_mark_diskspace_used(ac, NULL, 0);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	max = EXT4_CLUSTERS_PER_GROUP(sb);
+	i = mb_find_next_bit(bitmap, max, 0);
+	KUNIT_ASSERT_EQ(test, i, start);
+	i = mb_find_next_zero_bit(bitmap, max, i + 1);
+	KUNIT_ASSERT_EQ(test, i, start + len);
+	i = mb_find_next_bit(bitmap, max, i + 1);
+	KUNIT_ASSERT_EQ(test, max, i);
+}
+
+static void test_mark_diskspace_used(struct kunit *test)
+{
+	struct super_block *sb = (struct super_block *)test->priv;
+	struct inode *inode;
+	struct ext4_allocation_context ac;
+	struct test_range ranges[TEST_RANGE_COUNT];
+	int i;
+
+	mbt_generate_test_ranges(sb, ranges, TEST_RANGE_COUNT);
+
+	inode = kunit_kzalloc(test, sizeof(*inode), GFP_KERNEL);
+	if (!inode)
+		return;
+	inode->i_sb = sb;
+
+	ac.ac_status = AC_STATUS_FOUND;
+	ac.ac_sb = sb;
+	ac.ac_inode = inode;
+	for (i = 0; i < TEST_RANGE_COUNT; i++)
+		test_mark_diskspace_used_range(test, &ac, ranges[i].start,
+					       ranges[i].len);
+}
+
+static void mbt_generate_buddy(struct super_block *sb, void *buddy,
+			       void *bitmap, struct ext4_group_info *grp)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	uint32_t order, off;
+	void *bb, *bb_h;
+	int max;
+
+	memset(buddy, 0xff, sb->s_blocksize);
+	memset(grp, 0, offsetof(struct ext4_group_info,
+				 bb_counters[MB_NUM_ORDERS(sb)]));
+
+	bb = bitmap;
+	max = EXT4_CLUSTERS_PER_GROUP(sb);
+	bb_h = buddy + sbi->s_mb_offsets[1];
+
+	off = mb_find_next_zero_bit(bb, max, 0);
+	grp->bb_first_free = off;
+	while (off < max) {
+		grp->bb_counters[0]++;
+		grp->bb_free++;
+
+		if (!(off & 1) && !mb_test_bit(off + 1, bb)) {
+			grp->bb_free++;
+			grp->bb_counters[0]--;
+			mb_clear_bit(off >> 1, bb_h);
+			grp->bb_counters[1]++;
+			grp->bb_largest_free_order = 1;
+			off++;
+		}
+
+		off = mb_find_next_zero_bit(bb, max, off + 1);
+	}
+
+	for (order = 1; order < MB_NUM_ORDERS(sb) - 1; order++) {
+		bb = buddy + sbi->s_mb_offsets[order];
+		bb_h = buddy + sbi->s_mb_offsets[order + 1];
+		max = max >> 1;
+		off = mb_find_next_zero_bit(bb, max, 0);
+
+		while (off < max) {
+			if (!(off & 1) && !mb_test_bit(off + 1, bb)) {
+				mb_set_bits(bb, off, 2);
+				grp->bb_counters[order] -= 2;
+				mb_clear_bit(off >> 1, bb_h);
+				grp->bb_counters[order + 1]++;
+				grp->bb_largest_free_order = order + 1;
+				off++;
+			}
+
+			off = mb_find_next_zero_bit(bb, max, off + 1);
+		}
+	}
+
+	max = EXT4_CLUSTERS_PER_GROUP(sb);
+	off = mb_find_next_zero_bit(bitmap, max, 0);
+	while (off < max) {
+		grp->bb_fragments++;
+
+		off = mb_find_next_bit(bitmap, max, off + 1);
+		if (off + 1 >= max)
+			break;
+
+		off = mb_find_next_zero_bit(bitmap, max, off + 1);
+	}
+}
+
+static void
+mbt_validate_group_info(struct kunit *test, struct ext4_group_info *grp1,
+			struct ext4_group_info *grp2)
+{
+	struct super_block *sb = (struct super_block *)test->priv;
+	int i;
+
+	KUNIT_ASSERT_EQ(test, grp1->bb_first_free,
+			grp2->bb_first_free);
+	KUNIT_ASSERT_EQ(test, grp1->bb_fragments,
+			grp2->bb_fragments);
+	KUNIT_ASSERT_EQ(test, grp1->bb_free, grp2->bb_free);
+	KUNIT_ASSERT_EQ(test, grp1->bb_largest_free_order,
+			grp2->bb_largest_free_order);
+
+	for (i = 1; i < MB_NUM_ORDERS(sb); i++) {
+		KUNIT_ASSERT_EQ_MSG(test, grp1->bb_counters[i],
+				    grp2->bb_counters[i],
+				    "bb_counters[%d] diffs, expected %d, generated %d",
+				    i, grp1->bb_counters[i],
+				    grp2->bb_counters[i]);
+	}
+}
+
+static void
+do_test_generate_buddy(struct kunit *test, struct super_block *sb, void *bitmap,
+			   void *mbt_buddy, struct ext4_group_info *mbt_grp,
+			   void *ext4_buddy, struct ext4_group_info *ext4_grp)
+{
+	int i;
+
+	mbt_generate_buddy(sb, mbt_buddy, bitmap, mbt_grp);
+
+	for (i = 0; i < MB_NUM_ORDERS(sb); i++)
+		ext4_grp->bb_counters[i] = 0;
+	/* needed by validation in ext4_mb_generate_buddy */
+	ext4_grp->bb_free = mbt_grp->bb_free;
+	memset(ext4_buddy, 0xff, sb->s_blocksize);
+	ext4_mb_generate_buddy(sb, ext4_buddy, bitmap, TEST_GOAL_GROUP,
+			       ext4_grp);
+
+	KUNIT_ASSERT_EQ(test, memcmp(mbt_buddy, ext4_buddy, sb->s_blocksize),
+			0);
+	mbt_validate_group_info(test, mbt_grp, ext4_grp);
+}
+
+static void test_mb_generate_buddy(struct kunit *test)
+{
+	struct super_block *sb = (struct super_block *)test->priv;
+	void *bitmap, *expected_bb, *generate_bb;
+	struct ext4_group_info *expected_grp, *generate_grp;
+	struct test_range ranges[TEST_RANGE_COUNT];
+	int i;
+
+	bitmap = kunit_kzalloc(test, sb->s_blocksize, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bitmap);
+	expected_bb = kunit_kzalloc(test, sb->s_blocksize, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, expected_bb);
+	generate_bb = kunit_kzalloc(test, sb->s_blocksize, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, generate_bb);
+	expected_grp = kunit_kzalloc(test, offsetof(struct ext4_group_info,
+				bb_counters[MB_NUM_ORDERS(sb)]), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, expected_grp);
+	generate_grp = ext4_get_group_info(sb, TEST_GOAL_GROUP);
+	KUNIT_ASSERT_NOT_NULL(test, generate_grp);
+
+	mbt_generate_test_ranges(sb, ranges, TEST_RANGE_COUNT);
+	for (i = 0; i < TEST_RANGE_COUNT; i++) {
+		mb_set_bits(bitmap, ranges[i].start, ranges[i].len);
+		do_test_generate_buddy(test, sb, bitmap, expected_bb,
+				       expected_grp, generate_bb, generate_grp);
+	}
+}
+
+static void
+test_mb_mark_used_range(struct kunit *test, struct ext4_buddy *e4b,
+			ext4_grpblk_t start, ext4_grpblk_t len, void *bitmap,
+			void *buddy, struct ext4_group_info *grp)
+{
+	struct super_block *sb = (struct super_block *)test->priv;
+	struct ext4_free_extent ex;
+	int i;
+
+	/* mb_mark_used only accepts non-zero len */
+	if (len == 0)
+		return;
+
+	ex.fe_start = start;
+	ex.fe_len = len;
+	ex.fe_group = TEST_GOAL_GROUP;
+
+	ext4_lock_group(sb, TEST_GOAL_GROUP);
+	mb_mark_used(e4b, &ex);
+	ext4_unlock_group(sb, TEST_GOAL_GROUP);
+
+	mb_set_bits(bitmap, start, len);
+	/* bypass bb_free validatoin in ext4_mb_generate_buddy */
+	grp->bb_free -= len;
+	memset(buddy, 0xff, sb->s_blocksize);
+	for (i = 0; i < MB_NUM_ORDERS(sb); i++)
+		grp->bb_counters[i] = 0;
+	ext4_mb_generate_buddy(sb, buddy, bitmap, 0, grp);
+
+	KUNIT_ASSERT_EQ(test, memcmp(buddy, e4b->bd_buddy, sb->s_blocksize),
+			0);
+	mbt_validate_group_info(test, grp, e4b->bd_info);
+}
+
+static void test_mb_mark_used(struct kunit *test)
+{
+	struct ext4_buddy e4b;
+	struct super_block *sb = (struct super_block *)test->priv;
+	void *bitmap, *buddy;
+	struct ext4_group_info *grp;
+	int ret;
+	struct test_range ranges[TEST_RANGE_COUNT];
+	int i;
+
+	/* buddy cache assumes that each page contains at least one block */
+	if (sb->s_blocksize > PAGE_SIZE)
+		kunit_skip(test, "blocksize exceeds pagesize");
+
+	bitmap = kunit_kzalloc(test, sb->s_blocksize, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bitmap);
+	buddy = kunit_kzalloc(test, sb->s_blocksize, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buddy);
+	grp = kunit_kzalloc(test, offsetof(struct ext4_group_info,
+				bb_counters[MB_NUM_ORDERS(sb)]), GFP_KERNEL);
+
+	ret = ext4_mb_load_buddy(sb, TEST_GOAL_GROUP, &e4b);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	grp->bb_free = EXT4_CLUSTERS_PER_GROUP(sb);
+	mbt_generate_test_ranges(sb, ranges, TEST_RANGE_COUNT);
+	for (i = 0; i < TEST_RANGE_COUNT; i++)
+		test_mb_mark_used_range(test, &e4b, ranges[i].start,
+					ranges[i].len, bitmap, buddy, grp);
+
+	ext4_mb_unload_buddy(&e4b);
+}
+
+static void
+test_mb_free_blocks_range(struct kunit *test, struct ext4_buddy *e4b,
+			  ext4_grpblk_t start, ext4_grpblk_t len, void *bitmap,
+			  void *buddy, struct ext4_group_info *grp)
+{
+	struct super_block *sb = (struct super_block *)test->priv;
+	int i;
+
+	/* mb_free_blocks will WARN if len is 0 */
+	if (len == 0)
+		return;
+
+	ext4_lock_group(sb, e4b->bd_group);
+	mb_free_blocks(NULL, e4b, start, len);
+	ext4_unlock_group(sb, e4b->bd_group);
+
+	mb_clear_bits(bitmap, start, len);
+	/* bypass bb_free validatoin in ext4_mb_generate_buddy */
+	grp->bb_free += len;
+	memset(buddy, 0xff, sb->s_blocksize);
+	for (i = 0; i < MB_NUM_ORDERS(sb); i++)
+		grp->bb_counters[i] = 0;
+	ext4_mb_generate_buddy(sb, buddy, bitmap, 0, grp);
+
+	KUNIT_ASSERT_EQ(test, memcmp(buddy, e4b->bd_buddy, sb->s_blocksize),
+			0);
+	mbt_validate_group_info(test, grp, e4b->bd_info);
+
+}
+
+static void test_mb_free_blocks(struct kunit *test)
+{
+	struct ext4_buddy e4b;
+	struct super_block *sb = (struct super_block *)test->priv;
+	void *bitmap, *buddy;
+	struct ext4_group_info *grp;
+	struct ext4_free_extent ex;
+	int ret;
+	int i;
+	struct test_range ranges[TEST_RANGE_COUNT];
+
+	/* buddy cache assumes that each page contains at least one block */
+	if (sb->s_blocksize > PAGE_SIZE)
+		kunit_skip(test, "blocksize exceeds pagesize");
+
+	bitmap = kunit_kzalloc(test, sb->s_blocksize, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bitmap);
+	buddy = kunit_kzalloc(test, sb->s_blocksize, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buddy);
+	grp = kunit_kzalloc(test, offsetof(struct ext4_group_info,
+				bb_counters[MB_NUM_ORDERS(sb)]), GFP_KERNEL);
+
+	ret = ext4_mb_load_buddy(sb, TEST_GOAL_GROUP, &e4b);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	ex.fe_start = 0;
+	ex.fe_len = EXT4_CLUSTERS_PER_GROUP(sb);
+	ex.fe_group = TEST_GOAL_GROUP;
+
+	ext4_lock_group(sb, TEST_GOAL_GROUP);
+	mb_mark_used(&e4b, &ex);
+	ext4_unlock_group(sb, TEST_GOAL_GROUP);
+
+	grp->bb_free = 0;
+	memset(bitmap, 0xff, sb->s_blocksize);
+
+	mbt_generate_test_ranges(sb, ranges, TEST_RANGE_COUNT);
+	for (i = 0; i < TEST_RANGE_COUNT; i++)
+		test_mb_free_blocks_range(test, &e4b, ranges[i].start,
+					  ranges[i].len, bitmap, buddy, grp);
+
+	ext4_mb_unload_buddy(&e4b);
+}
+
 static const struct mbt_ext4_block_layout mbt_test_layouts[] = {
 	{
 		.blocksize_bits = 10,
@@ -334,6 +896,11 @@ KUNIT_ARRAY_PARAM(mbt_layouts, mbt_test_layouts, mbt_show_layout);
 
 static struct kunit_case mbt_test_cases[] = {
 	KUNIT_CASE_PARAM(test_new_blocks_simple, mbt_layouts_gen_params),
+	KUNIT_CASE_PARAM(test_free_blocks_simple, mbt_layouts_gen_params),
+	KUNIT_CASE_PARAM(test_mb_generate_buddy, mbt_layouts_gen_params),
+	KUNIT_CASE_PARAM(test_mb_mark_used, mbt_layouts_gen_params),
+	KUNIT_CASE_PARAM(test_mb_free_blocks, mbt_layouts_gen_params),
+	KUNIT_CASE_PARAM(test_mark_diskspace_used, mbt_layouts_gen_params),
 	{}
 };
 
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index e4f7cf9d89c4..12b3f196010b 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3015,8 +3015,8 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
 {
 	struct super_block *sb = pde_data(file_inode(seq->file));
 	ext4_group_t group = (ext4_group_t) ((unsigned long) v);
-	int i;
-	int err, buddy_loaded = 0;
+	int i, err;
+	char nbuf[16];
 	struct ext4_buddy e4b;
 	struct ext4_group_info *grinfo;
 	unsigned char blocksize_bits = min_t(unsigned char,
@@ -3043,23 +3043,26 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
 	if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
 		err = ext4_mb_load_buddy(sb, group, &e4b);
 		if (err) {
-			seq_printf(seq, "#%-5u: I/O error\n", group);
+			seq_printf(seq, "#%-5u: %s\n", group, ext4_decode_error(NULL, err, nbuf));
 			return 0;
 		}
-		buddy_loaded = 1;
+		ext4_mb_unload_buddy(&e4b);
 	}
 
+	/*
+	 * We care only about free space counters in the group info and
+	 * these are safe to access even after the buddy has been unloaded
+	 */
 	memcpy(&sg, grinfo, i);
-
-	if (buddy_loaded)
-		ext4_mb_unload_buddy(&e4b);
-
 	seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
 			sg.info.bb_fragments, sg.info.bb_first_free);
 	for (i = 0; i <= 13; i++)
 		seq_printf(seq, " %-5u", i <= blocksize_bits + 1 ?
 				sg.info.bb_counters[i] : 0);
-	seq_puts(seq, " ]\n");
+	seq_puts(seq, " ]");
+	if (EXT4_MB_GRP_BBITMAP_CORRUPT(&sg.info))
+		seq_puts(seq, " Block bitmap corrupted!");
+	seq_puts(seq, "\n");
 
 	return 0;
 }
@@ -3829,8 +3832,7 @@ void ext4_mb_release(struct super_block *sb)
 }
 
 static inline int ext4_issue_discard(struct super_block *sb,
-		ext4_group_t block_group, ext4_grpblk_t cluster, int count,
-		struct bio **biop)
+		ext4_group_t block_group, ext4_grpblk_t cluster, int count)
 {
 	ext4_fsblk_t discard_block;
 
@@ -3839,13 +3841,8 @@ static inline int ext4_issue_discard(struct super_block *sb,
 	count = EXT4_C2B(EXT4_SB(sb), count);
 	trace_ext4_discard_blocks(sb,
 			(unsigned long long) discard_block, count);
-	if (biop) {
-		return __blkdev_issue_discard(sb->s_bdev,
-			(sector_t)discard_block << (sb->s_blocksize_bits - 9),
-			(sector_t)count << (sb->s_blocksize_bits - 9),
-			GFP_NOFS, biop);
-	} else
-		return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
+
+	return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
 }
 
 static void ext4_free_data_in_buddy(struct super_block *sb,
@@ -5169,10 +5166,16 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
 			.fe_len = ac->ac_orig_goal_len,
 		};
 		loff_t orig_goal_end = extent_logical_end(sbi, &ex);
+		loff_t o_ex_end = extent_logical_end(sbi, &ac->ac_o_ex);
 
-		/* we can't allocate as much as normalizer wants.
-		 * so, found space must get proper lstart
-		 * to cover original request */
+		/*
+		 * We can't allocate as much as normalizer wants, so we try
+		 * to get proper lstart to cover the original request, except
+		 * when the goal doesn't cover the original request as below:
+		 *
+		 * orig_ex:2045/2055(10), isize:8417280 -> normalized:0/2048
+		 * best_ex:0/200(200) -> adjusted: 1848/2048(200)
+		 */
 		BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
 		BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
 
@@ -5184,7 +5187,7 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
 		 * 1. Check if best ex can be kept at end of goal (before
 		 *    cr_best_avail trimmed it) and still cover original start
 		 * 2. Else, check if best ex can be kept at start of goal and
-		 *    still cover original start
+		 *    still cover original end
 		 * 3. Else, keep the best ex at start of original request.
 		 */
 		ex.fe_len = ac->ac_b_ex.fe_len;
@@ -5194,7 +5197,7 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
 			goto adjust_bex;
 
 		ex.fe_logical = ac->ac_g_ex.fe_logical;
-		if (ac->ac_o_ex.fe_logical < extent_logical_end(sbi, &ex))
+		if (o_ex_end <= extent_logical_end(sbi, &ex))
 			goto adjust_bex;
 
 		ex.fe_logical = ac->ac_o_ex.fe_logical;
@@ -5202,7 +5205,6 @@ adjust_bex:
 		ac->ac_b_ex.fe_logical = ex.fe_logical;
 
 		BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
-		BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
 		BUG_ON(extent_logical_end(sbi, &ex) > orig_goal_end);
 	}
 
@@ -6487,8 +6489,14 @@ do_more:
 	} else {
 		if (test_opt(sb, DISCARD)) {
 			err = ext4_issue_discard(sb, block_group, bit,
-						 count_clusters, NULL);
-			if (err && err != -EOPNOTSUPP)
+						 count_clusters);
+			/*
+			 * Ignore EOPNOTSUPP error. This is consistent with
+			 * what happens when using journal.
+			 */
+			if (err == -EOPNOTSUPP)
+				err = 0;
+			if (err)
 				ext4_msg(sb, KERN_WARNING, "discard request in"
 					 " group:%u block:%d count:%lu failed"
 					 " with %d", block_group, bit, count,
@@ -6738,7 +6746,7 @@ __acquires(bitlock)
 	 */
 	mb_mark_used(e4b, &ex);
 	ext4_unlock_group(sb, group);
-	ret = ext4_issue_discard(sb, group, start, count, NULL);
+	ret = ext4_issue_discard(sb, group, start, count);
 	ext4_lock_group(sb, group);
 	mb_free_blocks(NULL, e4b, start, ex.fe_len);
 	return ret;
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 4d4a5a32e310..0ba9837d65ca 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1602,7 +1602,8 @@ exit_journal:
 		int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 		int gdb_num_end = ((group + flex_gd->count - 1) /
 				   EXT4_DESC_PER_BLOCK(sb));
-		int meta_bg = ext4_has_feature_meta_bg(sb);
+		int meta_bg = ext4_has_feature_meta_bg(sb) &&
+			      gdb_num >= le32_to_cpu(es->s_first_meta_bg);
 		sector_t padding_blocks = meta_bg ? 0 : sbi->s_sbh->b_blocknr -
 					 ext4_group_first_block_no(sb, 0);
 
@@ -2084,7 +2085,7 @@ retry:
 		}
 	}
 
-	if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
+	if ((!resize_inode && !meta_bg && n_desc_blocks > o_desc_blocks) || n_blocks_count == o_blocks_count) {
 		err = ext4_convert_meta_bg(sb, resize_inode);
 		if (err)
 			goto out;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f5e5a44778cf..cfb8449c731f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4421,22 +4421,6 @@ static int ext4_handle_clustersize(struct super_block *sb)
 		}
 		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
 			le32_to_cpu(es->s_log_block_size);
-		sbi->s_clusters_per_group =
-			le32_to_cpu(es->s_clusters_per_group);
-		if (sbi->s_clusters_per_group > sb->s_blocksize * 8) {
-			ext4_msg(sb, KERN_ERR,
-				 "#clusters per group too big: %lu",
-				 sbi->s_clusters_per_group);
-			return -EINVAL;
-		}
-		if (sbi->s_blocks_per_group !=
-		    (sbi->s_clusters_per_group * (clustersize / sb->s_blocksize))) {
-			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
-				 "clusters per group (%lu) inconsistent",
-				 sbi->s_blocks_per_group,
-				 sbi->s_clusters_per_group);
-			return -EINVAL;
-		}
 	} else {
 		if (clustersize != sb->s_blocksize) {
 			ext4_msg(sb, KERN_ERR,
@@ -4450,9 +4434,21 @@ static int ext4_handle_clustersize(struct super_block *sb)
 				 sbi->s_blocks_per_group);
 			return -EINVAL;
 		}
-		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
 		sbi->s_cluster_bits = 0;
 	}
+	sbi->s_clusters_per_group = le32_to_cpu(es->s_clusters_per_group);
+	if (sbi->s_clusters_per_group > sb->s_blocksize * 8) {
+		ext4_msg(sb, KERN_ERR, "#clusters per group too big: %lu",
+			 sbi->s_clusters_per_group);
+		return -EINVAL;
+	}
+	if (sbi->s_blocks_per_group !=
+	    (sbi->s_clusters_per_group * (clustersize / sb->s_blocksize))) {
+		ext4_msg(sb, KERN_ERR,
+			 "blocks per group (%lu) and clusters per group (%lu) inconsistent",
+			 sbi->s_blocks_per_group, sbi->s_clusters_per_group);
+		return -EINVAL;
+	}
 	sbi->s_cluster_ratio = clustersize / sb->s_blocksize;
 
 	/* Do we have standard group size of clustersize * 8 blocks ? */
@@ -6864,6 +6860,10 @@ static int ext4_write_dquot(struct dquot *dquot)
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 	ret = dquot_commit(dquot);
+	if (ret < 0)
+		ext4_error_err(dquot->dq_sb, -ret,
+			       "Failed to commit dquot type %d",
+			       dquot->dq_id.type);
 	err = ext4_journal_stop(handle);
 	if (!ret)
 		ret = err;
@@ -6880,6 +6880,10 @@ static int ext4_acquire_dquot(struct dquot *dquot)
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 	ret = dquot_acquire(dquot);
+	if (ret < 0)
+		ext4_error_err(dquot->dq_sb, -ret,
+			      "Failed to acquire dquot type %d",
+			      dquot->dq_id.type);
 	err = ext4_journal_stop(handle);
 	if (!ret)
 		ret = err;
@@ -6899,6 +6903,10 @@ static int ext4_release_dquot(struct dquot *dquot)
 		return PTR_ERR(handle);
 	}
 	ret = dquot_release(dquot);
+	if (ret < 0)
+		ext4_error_err(dquot->dq_sb, -ret,
+			       "Failed to release dquot type %d",
+			       dquot->dq_id.type);
 	err = ext4_journal_stop(handle);
 	if (!ret)
 		ret = err;
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 82dc5e673d5c..b67a176bfcf9 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1565,46 +1565,49 @@ ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
 /*
  * Add value of the EA in an inode.
  */
-static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
-					  const void *value, size_t value_len,
-					  struct inode **ret_inode)
+static struct inode *ext4_xattr_inode_lookup_create(handle_t *handle,
+		struct inode *inode, const void *value, size_t value_len)
 {
 	struct inode *ea_inode;
 	u32 hash;
 	int err;
 
+	/* Account inode & space to quota even if sharing... */
+	err = ext4_xattr_inode_alloc_quota(inode, value_len);
+	if (err)
+		return ERR_PTR(err);
+
 	hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
 	ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
 	if (ea_inode) {
 		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
-		if (err) {
-			iput(ea_inode);
-			return err;
-		}
-
-		*ret_inode = ea_inode;
-		return 0;
+		if (err)
+			goto out_err;
+		return ea_inode;
 	}
 
 	/* Create an inode for the EA value */
 	ea_inode = ext4_xattr_inode_create(handle, inode, hash);
-	if (IS_ERR(ea_inode))
-		return PTR_ERR(ea_inode);
+	if (IS_ERR(ea_inode)) {
+		ext4_xattr_inode_free_quota(inode, NULL, value_len);
+		return ea_inode;
+	}
 
 	err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
 	if (err) {
 		if (ext4_xattr_inode_dec_ref(handle, ea_inode))
 			ext4_warning_inode(ea_inode, "cleanup dec ref error %d", err);
-		iput(ea_inode);
-		return err;
+		goto out_err;
 	}
 
 	if (EA_INODE_CACHE(inode))
 		mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
 				      ea_inode->i_ino, true /* reusable */);
-
-	*ret_inode = ea_inode;
-	return 0;
+	return ea_inode;
+out_err:
+	iput(ea_inode);
+	ext4_xattr_inode_free_quota(inode, NULL, value_len);
+	return ERR_PTR(err);
 }
 
 /*
@@ -1712,16 +1715,11 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
 	if (i->value && in_inode) {
 		WARN_ON_ONCE(!i->value_len);
 
-		ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
-		if (ret)
-			goto out;
-
-		ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
-						     i->value_len,
-						     &new_ea_inode);
-		if (ret) {
+		new_ea_inode = ext4_xattr_inode_lookup_create(handle, inode,
+					i->value, i->value_len);
+		if (IS_ERR(new_ea_inode)) {
+			ret = PTR_ERR(new_ea_inode);
 			new_ea_inode = NULL;
-			ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
 			goto out;
 		}
 	}
@@ -2160,17 +2158,6 @@ getblk_failed:
 						      ENTRY(header(s->base)+1));
 			if (error)
 				goto getblk_failed;
-			if (ea_inode) {
-				/* Drop the extra ref on ea_inode. */
-				error = ext4_xattr_inode_dec_ref(handle,
-								 ea_inode);
-				if (error)
-					ext4_warning_inode(ea_inode,
-							   "dec ref error=%d",
-							   error);
-				iput(ea_inode);
-				ea_inode = NULL;
-			}
 
 			lock_buffer(new_bh);
 			error = ext4_journal_get_create_access(handle, sb,