[PATCH] ext4: recalculate s_blockfile_groups during resize2fs

[Eric Sandeen <sandeen@redhat.com>]

s_blockfile_groups is used to limit allocations for non-extent
files to block groups with block numbers less than 2^32.
However, it's not updated when the filesystem is resized online,
so the new groups are unavailable to non-extent files until a remount.

Fix this by updating the value in ext4_update_super() at
resize time.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index c169477..1357260 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1341,6 +1341,8 @@ static void ext4_update_super(struct super_block *sb,
 
 	/* Update the global fs size fields */
 	sbi->s_groups_count += flex_gd->count;
+	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
+			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
 
 	/* Update the reserved block counts only once the new group is
 	 * active. */