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From: David Sterba <dsterba@suse.cz>
To: dsterba@suse.cz, Zygo Blaxell <ce3g8jdj@umail.furryterror.org>,
	linux-btrfs@vger.kernel.org
Subject: Re: Regression in v5.14-rc1: f2165627319f btrfs: compression: don't try to compress if we don't have enough pages
Date: Thu, 26 Aug 2021 21:36:02 +0200	[thread overview]
Message-ID: <20210826193602.GR3379@twin.jikos.cz> (raw)
In-Reply-To: <20210823111715.GW5047@twin.jikos.cz>

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:
> > 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.

      reply	other threads:[~2021-08-26 19:38 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-22  5:51 Regression in v5.14-rc1: f2165627319f btrfs: compression: don't try to compress if we don't have enough pages Zygo Blaxell
2021-08-22  6:02 ` Zygo Blaxell
2021-08-23 11:17 ` David Sterba
2021-08-26 19:36   ` David Sterba [this message]

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