[PATCH 059/119] xfs: account for the refcount btree in the alloc/free log reservation

Darrick J. Wong
2016-06-17T01:24:16Z

Every time we allocate or free an extent, we might need to split the
refcount btree. Reserve some blocks in the transaction to handle
this possibility.

(Reproduced by generic/167 over NFS atop XFS)

Signed-off-by: Christoph Hellwig <hch@lst.de>
[darrick.wong@oracle.com: add commit message]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_trans_resv.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
index 7c840e1..a59838f 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.c
+++ b/fs/xfs/libxfs/xfs_trans_resv.c
@@ -67,7 +67,8 @@ xfs_calc_buf_res(
* Per-extent log reservation for the btree changes involved in freeing or
* allocating an extent. In classic XFS there were two trees that will be
* modified (bnobt + cntbt). With rmap enabled, there are three trees
- * (rmapbt). The number of blocks reserved is based on the formula:
+ * (rmapbt). With reflink, there are four trees (refcountbt). The number of
+ * blocks reserved is based on the formula:
*
* num trees * ((2 blocks/level * max depth) - 1)
*
@@ -83,6 +84,8 @@ xfs_allocfree_log_count(
blocks = num_ops * 2 * (2 * mp->m_ag_maxlevels - 1);
if (xfs_sb_version_hasrmapbt(&mp->m_sb))
blocks += num_ops * (2 * mp->m_rmap_maxlevels - 1);
+ if (xfs_sb_version_hasreflink(&mp->m_sb))
+ blocks += num_ops * (2 * mp->m_refc_maxlevels - 1);

return blocks;
}