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From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	xfs@oss.sgi.com
Subject: Re: block allocations for the refcount btree
Date: Fri, 12 Feb 2016 11:10:46 -0800	[thread overview]
Message-ID: <20160212191046.GA28421@infradead.org> (raw)
In-Reply-To: <20160210214058.GN14668@dastard>

On Thu, Feb 11, 2016 at 08:40:58AM +1100, Dave Chinner wrote:
> I run into that from time to time (maybe once a month) on a vanilla
> kernel.
> 
> IIRC, the problem is the delayed allocation extent split runs out of
> it's reserved block count if you split it enough times. The case
> I've seen is that  the indlen calculated in xfs_bmap_worst_indlen()
> ends up too small for a subsequent allocation after we've called
> xfs_bmap_del_extent() to delete the middle of a delalloc extent too
> many times.
> 
> Brian had some patches that attempted to solve it - we may have
> simply dropped the ball on this (again).
> 
> http://oss.sgi.com/archives/xfs/2014-09/msg00337.html

I'm pretty sure that is a separate issue.  With the refcount btree we may
allocate an extent (or rather just a single block) in xfs_alloc_ag_vextent
as called from xfs_refcountbt_alloc_block.  The reservation helps us to
ensure this block is always available, but we still need to account for
that in xfs_trans_reserve(), which we currently don't do for itruncate
transactions.  

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  parent reply	other threads:[~2016-02-12 19:10 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-10  9:30 block allocations for the refcount btree Christoph Hellwig
2016-02-10  9:50 ` Darrick J. Wong
2016-02-10 19:07   ` Christoph Hellwig
2016-02-10 21:40     ` Dave Chinner
2016-02-11 14:09       ` Brian Foster
2016-02-11 20:21         ` Dave Chinner
2016-02-12 19:10       ` Christoph Hellwig [this message]
2016-02-13  2:33         ` Dave Chinner
2016-02-13  4:44           ` Darrick J. Wong
2016-02-13  8:02             ` Christoph Hellwig
2016-02-13  7:48           ` Christoph Hellwig
2016-02-14  0:21             ` Dave Chinner
2016-03-01 18:18         ` Darrick J. Wong
2016-03-01 20:40           ` Christoph Hellwig
2016-03-02  5:24             ` Darrick J. Wong
2016-03-02  9:59               ` Christoph Hellwig
2016-03-02 16:41                 ` Darrick J. Wong
2016-03-02 16:57                   ` Christoph Hellwig
2016-03-02 21:21                     ` Darrick J. Wong
2016-03-03 14:05                       ` Christoph Hellwig
2016-03-04  1:36                         ` Darrick J. Wong

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