diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c
index 1f9ed117e78b..f9d6a4f9ca92 100644
--- a/fs/ocfs2/move_extents.c
+++ b/fs/ocfs2/move_extents.c
@@ -685,7 +685,7 @@ static int ocfs2_move_extent(struct ocfs2_move_extents_context *context,
 	}
 
 	ret = ocfs2_block_group_set_bits(handle, gb_inode, gd, gd_bh,
-					 goal_bit, len);
+					 goal_bit, len, 0, 0);
 	if (ret) {
 		ocfs2_rollback_alloc_dinode_counts(gb_inode, gb_bh, len,
 					       le16_to_cpu(gd->bg_chain));
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 7aebdbf5cc0a..c93689b568fe 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -883,7 +883,8 @@ struct ocfs2_group_desc
 	__le16	bg_free_bits_count;     /* Free bits count */
 	__le16   bg_chain;               /* What chain I am in. */
 /*10*/	__le32   bg_generation;
-	__le32	bg_reserved1;
+	__le16   bg_contig_free_bits;   /* max contig free bits length */
+	__le16   bg_reserved1;
 	__le64   bg_next_group;          /* Next group in my list, in
 					   blocks */
 /*20*/	__le64   bg_parent_dinode;       /* dinode which owns me, in
diff --git a/fs/ocfs2/resize.c b/fs/ocfs2/resize.c
index d65d43c61857..c4a4016d3866 100644
--- a/fs/ocfs2/resize.c
+++ b/fs/ocfs2/resize.c
@@ -91,6 +91,8 @@ static int ocfs2_update_last_group_and_inode(handle_t *handle,
 	u16 cl_bpc = le16_to_cpu(cl->cl_bpc);
 	u16 cl_cpg = le16_to_cpu(cl->cl_cpg);
 	u16 old_bg_clusters;
+	u16 contig_bits;
+	__le16 old_bg_contig_free_bits;
 
 	trace_ocfs2_update_last_group_and_inode(new_clusters,
 						first_new_cluster);
@@ -122,6 +124,11 @@ static int ocfs2_update_last_group_and_inode(handle_t *handle,
 		le16_add_cpu(&group->bg_free_bits_count, -1 * backups);
 	}
 
+	contig_bits = ocfs2_find_max_contig_free_bits(group->bg_bitmap,
+					le16_to_cpu(group->bg_bits), 0);
+	old_bg_contig_free_bits = group->bg_contig_free_bits;
+	group->bg_contig_free_bits = cpu_to_le16(contig_bits);
+
 	ocfs2_journal_dirty(handle, group_bh);
 
 	/* update the inode accordingly. */
@@ -160,6 +167,7 @@ static int ocfs2_update_last_group_and_inode(handle_t *handle,
 		le16_add_cpu(&group->bg_free_bits_count, backups);
 		le16_add_cpu(&group->bg_bits, -1 * num_bits);
 		le16_add_cpu(&group->bg_free_bits_count, -1 * num_bits);
+		group->bg_contig_free_bits = old_bg_contig_free_bits;
 	}
 out:
 	if (ret)
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 166c8918c825..1a7b53fd468d 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -50,6 +50,10 @@ struct ocfs2_suballoc_result {
 	u64		sr_blkno;	/* The first allocated block */
 	unsigned int	sr_bit_offset;	/* The bit in the bg */
 	unsigned int	sr_bits;	/* How many bits we claimed */
+	unsigned int	sr_max_contig_bits; /* The length for contiguous
+					     * free bits, only available
+					     * for cluster group
+					     */
 };
 
 static u64 ocfs2_group_from_res(struct ocfs2_suballoc_result *res)
@@ -1272,6 +1276,26 @@ static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh,
 	return ret;
 }
 
+u16 ocfs2_find_max_contig_free_bits(void *bitmap,
+			 u16 total_bits, u16 start)
+{
+	u16 offset, free_bits;
+	u16 contig_bits = 0;
+
+	while (start < total_bits) {
+		offset = ocfs2_find_next_zero_bit(bitmap, total_bits, start);
+		if (offset == total_bits)
+			break;
+
+		start = ocfs2_find_next_bit(bitmap, total_bits, offset);
+		free_bits = start - offset;
+		if (contig_bits < free_bits)
+			contig_bits = free_bits;
+	}
+
+	return contig_bits;
+}
+
 static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb,
 					     struct buffer_head *bg_bh,
 					     unsigned int bits_wanted,
@@ -1280,6 +1304,7 @@ static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb,
 {
 	void *bitmap;
 	u16 best_offset, best_size;
+	u16 prev_best_size = 0;
 	int offset, start, found, status = 0;
 	struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
 
@@ -1308,6 +1333,7 @@ static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb,
 			/* got a zero after some ones */
 			found = 1;
 			start = offset + 1;
+			prev_best_size = best_size;
 		}
 		if (found > best_size) {
 			best_size = found;
@@ -1320,6 +1346,8 @@ static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb,
 		}
 	}
 
+	/* best_size will be allocated, we save prev_best_size */
+	res->sr_max_contig_bits = prev_best_size;
 	if (best_size) {
 		res->sr_bit_offset = best_offset;
 		res->sr_bits = best_size;
@@ -1337,11 +1365,15 @@ int ocfs2_block_group_set_bits(handle_t *handle,
 					     struct ocfs2_group_desc *bg,
 					     struct buffer_head *group_bh,
 					     unsigned int bit_off,
-					     unsigned int num_bits)
+					     unsigned int num_bits,
+					     unsigned int max_contig_bits,
+					     int fastpath)
 {
 	int status;
 	void *bitmap = bg->bg_bitmap;
 	int journal_type = OCFS2_JOURNAL_ACCESS_WRITE;
+	unsigned int start = bit_off + num_bits;
+	u16 contig_bits;
 
 	/* All callers get the descriptor via
 	 * ocfs2_read_group_descriptor().  Any corruption is a code bug. */
@@ -1373,6 +1405,28 @@ int ocfs2_block_group_set_bits(handle_t *handle,
 	while(num_bits--)
 		ocfs2_set_bit(bit_off++, bitmap);
 
+	/*
+	 * this is optimize path, caller set old contig value
+	 * in max_contig_bits to bypass finding action.
+	 */
+	if (fastpath) {
+		bg->bg_contig_free_bits = cpu_to_le16(max_contig_bits);
+	} else if (ocfs2_is_cluster_bitmap(alloc_inode)) {
+		/*
+		 * Usually, the block group bitmap allocates only 1 bit
+		 * at a time, while the cluster group allocates n bits
+		 * each time. Therefore, we only save the contig bits for
+		 * the cluster group.
+		 */
+		contig_bits = ocfs2_find_max_contig_free_bits(bitmap,
+				    le16_to_cpu(bg->bg_bits), start);
+		if (contig_bits > max_contig_bits)
+			max_contig_bits = contig_bits;
+		bg->bg_contig_free_bits = cpu_to_le16(max_contig_bits);
+	} else {
+		bg->bg_contig_free_bits = 0;
+	}
+
 	ocfs2_journal_dirty(handle, group_bh);
 
 bail:
@@ -1486,7 +1540,12 @@ static int ocfs2_cluster_group_search(struct inode *inode,
 
 	BUG_ON(!ocfs2_is_cluster_bitmap(inode));
 
-	if (gd->bg_free_bits_count) {
+	if (le16_to_cpu(gd->bg_contig_free_bits) &&
+	    le16_to_cpu(gd->bg_contig_free_bits) < bits_wanted)
+		return -ENOSPC;
+
+	/* ->bg_contig_free_bits may un-initialized, so compare again */
+	if (le16_to_cpu(gd->bg_free_bits_count) >= bits_wanted) {
 		max_bits = le16_to_cpu(gd->bg_bits);
 
 		/* Tail groups in cluster bitmaps which aren't cpg
@@ -1555,7 +1614,7 @@ static int ocfs2_block_group_search(struct inode *inode,
 	BUG_ON(min_bits != 1);
 	BUG_ON(ocfs2_is_cluster_bitmap(inode));
 
-	if (bg->bg_free_bits_count) {
+	if (le16_to_cpu(bg->bg_free_bits_count) >= bits_wanted) {
 		ret = ocfs2_block_group_find_clear_bits(OCFS2_SB(inode->i_sb),
 							group_bh, bits_wanted,
 							le16_to_cpu(bg->bg_bits),
@@ -1715,7 +1774,8 @@ static int ocfs2_search_one_group(struct ocfs2_alloc_context *ac,
 	}
 
 	ret = ocfs2_block_group_set_bits(handle, alloc_inode, gd, group_bh,
-					 res->sr_bit_offset, res->sr_bits);
+					 res->sr_bit_offset, res->sr_bits,
+					 res->sr_max_contig_bits, 0);
 	if (ret < 0) {
 		ocfs2_rollback_alloc_dinode_counts(alloc_inode, ac->ac_bh,
 					       res->sr_bits,
@@ -1849,7 +1909,9 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
 					    bg,
 					    group_bh,
 					    res->sr_bit_offset,
-					    res->sr_bits);
+					    res->sr_bits,
+					    res->sr_max_contig_bits,
+					    0);
 	if (status < 0) {
 		ocfs2_rollback_alloc_dinode_counts(alloc_inode,
 					ac->ac_bh, res->sr_bits, chain);
@@ -2163,7 +2225,9 @@ int ocfs2_claim_new_inode_at_loc(handle_t *handle,
 					 bg,
 					 bg_bh,
 					 res->sr_bit_offset,
-					 res->sr_bits);
+					 res->sr_bits,
+					 res->sr_max_contig_bits,
+					 0);
 	if (ret < 0) {
 		ocfs2_rollback_alloc_dinode_counts(ac->ac_inode,
 					       ac->ac_bh, res->sr_bits, chain);
@@ -2382,11 +2446,13 @@ static int ocfs2_block_group_clear_bits(handle_t *handle,
 					struct buffer_head *group_bh,
 					unsigned int bit_off,
 					unsigned int num_bits,
+					unsigned int max_contig_bits,
 					void (*undo_fn)(unsigned int bit,
 							unsigned long *bmap))
 {
 	int status;
 	unsigned int tmp;
+	u16 contig_bits;
 	struct ocfs2_group_desc *undo_bg = NULL;
 	struct journal_head *jh;
 
@@ -2433,6 +2499,20 @@ static int ocfs2_block_group_clear_bits(handle_t *handle,
 				   num_bits);
 	}
 
+	/*
+	 * TODO: even 'num_bits == 1' (the worst case, release 1 cluster),
+	 * we still need to rescan whole bitmap.
+	 */
+	if (ocfs2_is_cluster_bitmap(alloc_inode)) {
+		contig_bits = ocfs2_find_max_contig_free_bits(bg->bg_bitmap,
+				    le16_to_cpu(bg->bg_bits), 0);
+		if (contig_bits > max_contig_bits)
+			max_contig_bits = contig_bits;
+		bg->bg_contig_free_bits = cpu_to_le16(max_contig_bits);
+	} else {
+		bg->bg_contig_free_bits = 0;
+	}
+
 	if (undo_fn)
 		spin_unlock(&jh->b_state_lock);
 
@@ -2459,6 +2539,7 @@ static int _ocfs2_free_suballoc_bits(handle_t *handle,
 	struct ocfs2_chain_list *cl = &fe->id2.i_chain;
 	struct buffer_head *group_bh = NULL;
 	struct ocfs2_group_desc *group;
+	__le16 old_bg_contig_free_bits = 0;
 
 	/* The alloc_bh comes from ocfs2_free_dinode() or
 	 * ocfs2_free_clusters().  The callers have all locked the
@@ -2483,9 +2564,11 @@ static int _ocfs2_free_suballoc_bits(handle_t *handle,
 
 	BUG_ON((count + start_bit) > le16_to_cpu(group->bg_bits));
 
+	if (ocfs2_is_cluster_bitmap(alloc_inode))
+		old_bg_contig_free_bits = group->bg_contig_free_bits;
 	status = ocfs2_block_group_clear_bits(handle, alloc_inode,
 					      group, group_bh,
-					      start_bit, count, undo_fn);
+					      start_bit, count, 0, undo_fn);
 	if (status < 0) {
 		mlog_errno(status);
 		goto bail;
@@ -2496,7 +2579,8 @@ static int _ocfs2_free_suballoc_bits(handle_t *handle,
 	if (status < 0) {
 		mlog_errno(status);
 		ocfs2_block_group_set_bits(handle, alloc_inode, group, group_bh,
-				start_bit, count);
+				start_bit, count,
+				le16_to_cpu(old_bg_contig_free_bits), 1);
 		goto bail;
 	}
 
diff --git a/fs/ocfs2/suballoc.h b/fs/ocfs2/suballoc.h
index 9c74eace3adc..b481b834857d 100644
--- a/fs/ocfs2/suballoc.h
+++ b/fs/ocfs2/suballoc.h
@@ -79,12 +79,16 @@ void ocfs2_rollback_alloc_dinode_counts(struct inode *inode,
 			 struct buffer_head *di_bh,
 			 u32 num_bits,
 			 u16 chain);
+u16 ocfs2_find_max_contig_free_bits(void *bitmap,
+			 u16 total_bits, u16 start);
 int ocfs2_block_group_set_bits(handle_t *handle,
 			 struct inode *alloc_inode,
 			 struct ocfs2_group_desc *bg,
 			 struct buffer_head *group_bh,
 			 unsigned int bit_off,
-			 unsigned int num_bits);
+			 unsigned int num_bits,
+			 unsigned int max_contig_bits,
+			 int fastpath);
 
 int ocfs2_claim_metadata(handle_t *handle,
 			 struct ocfs2_alloc_context *ac,
