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Diffstat (limited to 'fs/btrfs/free-space-cache.c')
-rw-r--r--fs/btrfs/free-space-cache.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 0be7a8742a43..c8090f18c217 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1356,6 +1356,8 @@ static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
+ max_bitmaps = max(max_bitmaps, 1);
+
BUG_ON(ctl->total_bitmaps > max_bitmaps);
/*
@@ -1636,10 +1638,14 @@ static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
}
/*
- * some block groups are so tiny they can't be enveloped by a bitmap, so
- * don't even bother to create a bitmap for this
+ * The original block groups from mkfs can be really small, like 8
+ * megabytes, so don't bother with a bitmap for those entries. However
+ * some block groups can be smaller than what a bitmap would cover but
+ * are still large enough that they could overflow the 32k memory limit,
+ * so allow those block groups to still be allowed to have a bitmap
+ * entry.
*/
- if (BITS_PER_BITMAP * ctl->unit > block_group->key.offset)
+ if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
return false;
return true;