XFS: fix zoned gc threshold math for 32-bit arches
xfs_zoned_need_gc makes use of mult_frac() to calculate the threshold
for triggering the zoned garbage collector, but, turns out mult_frac()
doesn't properly work with 64-bit data types and this caused build
failures on some 32-bit architectures.
Fix this by essentially open coding mult_frac() in a 64-bit friendly
way.
Notice we don't need to bother with counters underflow here because
xfs_estimate_freecounter() will always return a positive value, as it
leverages percpu_counter_read_positive to read such counters.
Fixes: 845abeb1f06a ("xfs: add tunable threshold parameter for triggering zone GC")
diff --git a/fs/xfs/xfs_zone_gc.c b/fs/xfs/xfs_zone_gc.c
index 8c541ca..81c94dd 100644
--- a/fs/xfs/xfs_zone_gc.c
+++ b/fs/xfs/xfs_zone_gc.c
@@ -170,7 +170,8 @@ bool
xfs_zoned_need_gc(
struct xfs_mount *mp)
{
- s64 available, free;
+ s64 available, free, threshold;
+ s32 remainder;
if (!xfs_group_marked(mp, XG_TYPE_RTG, XFS_RTG_RECLAIMABLE))
return false;
@@ -183,7 +184,12 @@ xfs_zoned_need_gc(
return true;
free = xfs_estimate_freecounter(mp, XC_FREE_RTEXTENTS);
- if (available < mult_frac(free, mp->m_zonegc_low_space, 100))
+
+ threshold = div_s64_rem(free, 100, &remainder);
+ threshold = threshold * mp->m_zonegc_low_space +
+ remainder * div_s64(mp->m_zonegc_low_space, 100);
+
+ if (available < threshold)
return true;
return false;
