bcachefs: bch_member.btree_allocated_bitmap

This adds a small (64 bit) per-device bitmap that tracks ranges that
have btree nodes, for accelerating btree node scan if it is ever needed.

- New helpers, bch2_dev_btree_bitmap_marked() and
  bch2_dev_bitmap_mark(), for checking and updating the bitmap

- Interior btree update path updates the bitmaps when required

- The check_allocations pass has a new fsck_err check,
  btree_bitmap_not_marked

- New on disk format version, mi_btree_mitmap, which indicates the new
  bitmap is present

- Upgrade table lists the required recovery pass and expected fsck error

- Btree node scan uses the bitmap to skip ranges if we're on the new
  version

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/bcachefs/super_types.h b/fs/bcachefs/super_types.h
index ec784d975f66..11bcef170c2c 100644
--- a/fs/bcachefs/super_types.h
+++ b/fs/bcachefs/super_types.h
@@ -37,6 +37,8 @@ struct bch_member_cpu {
 	u8			durability;
 	u8			freespace_initialized;
 	u8			valid;
+	u8			btree_bitmap_shift;
+	u64			btree_allocated_bitmap;
 };
 
 #endif /* _BCACHEFS_SUPER_TYPES_H */