From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, xfs@oss.sgi.com
Subject: Re: reflink log reservations
Date: Thu, 4 Feb 2016 14:31:33 +0100 [thread overview]
Message-ID: <20160204133133.GA28701@lst.de> (raw)
In-Reply-To: <20160204081620.GL20038@birch.djwong.org>
On Thu, Feb 04, 2016 at 12:16:20AM -0800, Darrick J. Wong wrote:
> On Thu, Feb 04, 2016 at 08:46:17AM +0100, Christoph Hellwig wrote:
> > Hi Darrick,
> >
> > I'm running into the following log reservation assert after a few
> > xfstests runs over NFS. I'll try to understand the reservation
> > calculations, but in case this is still fresh in your head here's
> > a headsup:
>
> Hmm, interesting, I haven't seen /that/ one... my guess is that the
> block reservation needs to be bumped up for the refcount tree.
This seems to fix it for me:
---
>From 6e27eb42ece3a25f610690487b403a0091cafa26 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Thu, 4 Feb 2016 13:50:16 +0100
Subject: xfs: account for the refcount btree in the alloc/free log reservation
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/libxfs/xfs_trans_resv.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
index d495f82..f4c2648 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.c
+++ b/fs/xfs/libxfs/xfs_trans_resv.c
@@ -65,12 +65,15 @@ xfs_calc_buf_res(
/*
* Per-extent log reservation for the allocation btree changes
- * involved in freeing or allocating an extent. When rmap is not enabled,
- * there are only two trees that will be modified (free space trees), and when
- * rmap is enabled there will be three (freespace + rmap trees). The number of
- * blocks reserved is based on the formula:
+ * involved in freeing or allocating an extent.
*
- * num trees * ((2 blocks/level * max depth) - 1)
+ * There are at least two trees that will be modified (free space trees), when
+ * rmap is enabled there will be an additional rmap tree, and when reflinks
+ * are enabled there will be a refcount btree as well
+ *
+ * The number of blocks reserved is based on the formula:
+ *
+ * num trees * ((2 blocks/level * max depth) - 1)
*/
static uint
xfs_allocfree_log_count(
@@ -81,6 +84,8 @@ xfs_allocfree_log_count(
if (xfs_sb_version_hasrmapbt(&mp->m_sb))
num_trees++;
+ if (xfs_sb_version_hasreflink(&mp->m_sb))
+ num_trees++;
return num_ops * num_trees * (2 * mp->m_ag_maxlevels - 1);
}
--
2.1.4
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next prev parent reply other threads:[~2016-02-04 13:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-04 7:46 reflink log reservations Christoph Hellwig
2016-02-04 8:16 ` Darrick J. Wong
2016-02-04 13:31 ` Christoph Hellwig [this message]
2016-02-04 18:05 ` Darrick J. Wong
2016-02-09 16:31 ` Christoph Hellwig
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