Re: [PATCH] Btrfs: fix compressed write corruption on enospc

From: Hugo Mills <hugo@carfax.org.uk>
To: Martin Steigerwald <Martin@lichtvoll.de>
Cc: Liu Bo <bo.li.liu@oracle.com>,
	linux-btrfs@vger.kernel.org, Chris Mason <clm@fb.com>
Subject: Re: [PATCH] Btrfs: fix compressed write corruption on enospc
Date: Wed, 6 Aug 2014 11:29:19 +0100	[thread overview]
Message-ID: <20140806102918.GA3968@carfax.org.uk> (raw)
In-Reply-To: <3143412.n5KSJct7YP@merkaba>

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On Wed, Aug 06, 2014 at 12:21:59PM +0200, Martin Steigerwald wrote:
> It basically happened on about the first heavy write I/O occasion after
> the BTRFS trees filled the complete device:
> 
> I am now balancing the trees down to lower sizes manually with
> 
> btrfs balance start -dusage=10 /home
> 
> btrfs balance start -musage=10 /home

   Note that balance has nothing to do with balancing the metadata
trees. The tree structures are automatically balanced as part of their
normal operation. A "btrfs balance start" is a much higher-level
operation. It's called balance because the overall effect is to
balance the data usage evenly across multiple devices. (Actually, to
balance the available space evenly).

   Also note that the data part isn't tree-structured, so referring to
"balancing the trees" with a -d flag is doubly misleading. :)

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
  PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
   --- You know... I'm sure this code would seem a lot better if I ---   
                         never tried running it.                         

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