Update flex_bg free blocks and free inodes counters when resizing.

This fixes a bug which prevented the newly created inodes after a
resize from being used on filesystems with flex_bg.
Signed-off-by: Frederic Bohe <frederic.bohe@bull.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/resize.c

@@ -929,6 +929,15 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
 	percpu_counter_add(&sbi->s_freeinodes_counter,
 			   EXT4_INODES_PER_GROUP(sb));
 
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
+		ext4_group_t flex_group;
+		flex_group = ext4_flex_group(sbi, input->group);
+		sbi->s_flex_groups[flex_group].free_blocks +=
+			input->free_blocks_count;
+		sbi->s_flex_groups[flex_group].free_inodes +=
+			EXT4_INODES_PER_GROUP(sb);
+	}
+
 	ext4_journal_dirty_metadata(handle, sbi->s_sbh);
 	sb->s_dirt = 1;
 

fs/ext4/super.c

@@ -1507,7 +1507,10 @@ static int ext4_fill_flex_info(struct super_block *sb)
 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
 	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
 
-	flex_group_count = (sbi->s_groups_count + groups_per_flex - 1) /
+	/* We allocate both existing and potentially added groups */
+	flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) +
+			    ((sbi->s_es->s_reserved_gdt_blocks +1 ) <<
+			      EXT4_DESC_PER_BLOCK_BITS(sb))) /
 			   groups_per_flex;
 	sbi->s_flex_groups = kzalloc(flex_group_count *
 				     sizeof(struct flex_groups), GFP_KERNEL);