bcachefs: Prep work for variable size btree node buffers

bcachefs btree nodes are big - typically 256k - and btree roots are
pinned in memory. As we're now up to 18 btrees, we now have significant
memory overhead in mostly empty btree roots.

And in the future we're going to start enforcing that certain btree node
boundaries exist, to solve lock contention issues - analagous to XFS's
AGIs.

Thus, we need to start allocating smaller btree node buffers when we
can. This patch changes code that refers to the filesystem constant
c->opts.btree_node_size to refer to the btree node buffer size -
btree_buf_bytes() - where appropriate.

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

1 files changed, 0 insertions, 5 deletions

diff --git a/fs/bcachefs/bcachefs.h b/fs/bcachefs/bcachefs.h
index dac383e37181..b80c6c9efd8c 100644
--- a/fs/bcachefs/bcachefs.h
+++ b/fs/bcachefs/bcachefs.h
@@ -1204,11 +1204,6 @@ static inline unsigned block_sectors(const struct bch_fs *c)
 	return c->opts.block_size >> 9;
 }
 
-static inline size_t btree_sectors(const struct bch_fs *c)
-{
-	return c->opts.btree_node_size >> 9;
-}
-
 static inline bool btree_id_cached(const struct bch_fs *c, enum btree_id btree)
 {
 	return c->btree_key_cache_btrees & (1U << btree);