On Mon, Aug 23, 2021 at 01:17:15PM +0200, David Sterba wrote:

On Sun, Aug 22, 2021 at 01:51:15AM -0400, Zygo Blaxell wrote:

quoted

Before this commit:

	# head /dev/zero -c 4095 > inline
	# compsize inline
	Type       Perc     Disk Usage   Uncompressed Referenced  
	TOTAL        0%       18B         3.9K         3.9K       
	zstd         0%       18B         3.9K         3.9K       

After this commit:

	# head /dev/zero -c 4095 > inline                                                                        
	# compsize inline                                                                                        
	Processed 1 file, 1 regular extents (1 refs), 0 inline.                                                                                      
	Type       Perc     Disk Usage   Uncompressed Referenced                                                                                     
	TOTAL      100%      4.0K         4.0K         4.0K                                                                                          
	none       100%      4.0K         4.0K         4.0K                                                                                          

This change makes the metadata sizes of trees of small files (e.g. source
checkouts) blow up.

It looks like we need to look at the offset of the extent, as well as
its length.

Thanks for the report, my bad, I'll look into it.

The patch has been reverted in Linus' tree so it'll be in 5.14 final and
will be in the upcoming stable updates according to their release
schedule.