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Diffstat (limited to 'fs/btrfs/block-group.c')
-rw-r--r--fs/btrfs/block-group.c18
1 files changed, 11 insertions, 7 deletions
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 0dcf7fecaf55..91440ef79a26 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1678,6 +1678,17 @@ void btrfs_reclaim_bgs_work(struct work_struct *work)
up_write(&space_info->groups_sem);
goto next;
}
+
+ /*
+ * Cache the zone_unusable value before turning the block group
+ * to read only. As soon as the block group is read only it's
+ * zone_unusable value gets moved to the block group's read-only
+ * bytes and isn't available for calculations anymore. We also
+ * cache it before unlocking the block group, to prevent races
+ * (reports from KCSAN and such tools) with tasks updating it.
+ */
+ zone_unusable = bg->zone_unusable;
+
spin_unlock(&bg->lock);
/*
@@ -1693,13 +1704,6 @@ void btrfs_reclaim_bgs_work(struct work_struct *work)
goto next;
}
- /*
- * Cache the zone_unusable value before turning the block group
- * to read only. As soon as the blog group is read only it's
- * zone_unusable value gets moved to the block group's read-only
- * bytes and isn't available for calculations anymore.
- */
- zone_unusable = bg->zone_unusable;
ret = inc_block_group_ro(bg, 0);
up_write(&space_info->groups_sem);
if (ret < 0)