On Mon 14-06-21 15:38:57, Andreas Dilger wrote:

quoted

On Jun 14, 2021, at 3:28 PM, Jan Kara [off-list ref] wrote:

When adding or removing journal from a filesystem, we also need to add /
remove journal blocks from overhead stored in the superblock.  Otherwise
total number of blocks in the filesystem as reported by statfs(2) need
not match reality and could lead to odd results like negative number of
used blocks reported by df(1).

Signed-off-by: Jan Kara <jack@suse.cz>

You could add:

Fixes: 9046b4dfd0ce ("mke2fs: set overhead in super block")

and

Reviewed-by: Andreas Dilger <redacted>

Thanks!

That also makes me wonder if resize2fs also needs to recalculate or
invalidate the s_overhead_clusters field when adding new block groups.
It *looks* like that is done correctly in adjust_fs_info() already?

Yes. From a quick look I had when doing this tune2fs patch I've noticed
that adjust_fs_info() just zeros s_overhead_clusters which makes the kernel
compute the overhead instead...

								Honza

-- 
Jan Kara [off-list ref]
SUSE Labs, CR