[PATCH 1/2] xfs_repair: adjust btree bulkloading slack computations to match online repair

Darrick J. Wong
2024-03-26T03:20:35Z

From: Darrick J. Wong <djwong@kernel.org>

Adjust the lowspace threshold in the new btree block slack computation
code to match online repair, which uses a straight 10% instead of magic
shifting to approximate that without division. Repairs aren't that
frequent in the kernel; and userspace can always do u64 division.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>
---
repair/bulkload.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/repair/bulkload.c b/repair/bulkload.c
index 8dd0a0c3908b..0117f69416cf 100644
--- a/repair/bulkload.c
+++ b/repair/bulkload.c
@@ -106,9 +106,10 @@ bulkload_claim_block(
* exceptions to this rule:
*
* (1) If someone turned one of the debug knobs.
- * (2) The AG has less than ~9% space free.
+ * (2) The AG has less than ~10% space free.
*
- * Note that we actually use 3/32 for the comparison to avoid division.
+ * In the latter case, format the new btree blocks almost completely full to
+ * minimize space usage.
*/
void
bulkload_estimate_ag_slack(
@@ -124,8 +125,8 @@ bulkload_estimate_ag_slack(
bload->leaf_slack = bload_leaf_slack;
bload->node_slack = bload_node_slack;

- /* No further changes if there's more than 3/32ths space left. */
- if (free >= ((sc->mp->m_sb.sb_agblocks * 3) >> 5))
+ /* No further changes if there's more than 10% space left. */
+ if (free >= sc->mp->m_sb.sb_agblocks / 10)
return;

/*