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| author | Darrick J. Wong <darrick.wong@oracle.com> | 2016-10-03 19:11:19 +0300 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2016-10-03 19:11:19 +0300 |
| commit | f310bd2ecd37b17bf0042c9d1595329057970eb6 (patch) | |
| tree | 50b6ae5b0f6465de86ddd81b1b95a1d7f12f15fa /fs/xfs/libxfs/xfs_trans_resv.c | |
| parent | ac4fef69386afb1c25d6b900fe1fcf77b96ea567 (diff) | |
| download | linux-f310bd2ecd37b17bf0042c9d1595329057970eb6.tar.xz | |
xfs: account for the refcount btree in the alloc/free log reservation
Every time we allocate or free a data extent, we might need to split
the refcount btree. Reserve some blocks in the transaction to handle
this possibility. Even though the deferred refcount code can roll a
transaction to avoid overloading the transaction, we can still exceed
the reservation.
Certain pathological workloads (1k blocks, no cowextsize hint, random
directio writes), cause a perfect storm wherein a refcount adjustment
of a large range of blocks causes full tree splits in two separate
extents in two separate refcount tree blocks; allocating new refcount
tree blocks causes rmap btree splits; and all the allocation activity
causes the freespace btrees to split, blowing the reservation.
(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>
Diffstat (limited to 'fs/xfs/libxfs/xfs_trans_resv.c')
| -rw-r--r-- | fs/xfs/libxfs/xfs_trans_resv.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c index 7c840e1c8bb6..a59838f1627b 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; } |