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>
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 4392e3f..b60afbc 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -929,6 +929,15 @@
 	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;