bcachefs: improved rw_aux_tree_bsearch()

shouldn't be any reason for an actual binary search here

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

diff --git a/fs/bcachefs/bset.c b/fs/bcachefs/bset.c
index faf58b4c0eb4593383bbdc6aa11d4f51dd8d3acf..a74e93a7215cb27a38825843c24f9536ed434ee8 100644 (file)
--- a/fs/bcachefs/bset.c
+++ b/fs/bcachefs/bset.c
@@ -614,28 +614,30 @@ static unsigned rw_aux_tree_bsearch(struct btree *b,
                                    struct bset_tree *t,
                                    unsigned offset)
 {
-       unsigned l = 0, r = t->size;
+       unsigned bset_offs = offset - btree_bkey_first_offset(t);
+       unsigned bset_u64s = t->end_offset - btree_bkey_first_offset(t);
+       unsigned idx = bset_u64s ? bset_offs * t->size / bset_u64s : 0;
 
        EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
+       EBUG_ON(!t->size);
+       EBUG_ON(idx > t->size);
 
-       while (l < r) {
-               unsigned m = (l + r) >> 1;
+       while (idx < t->size &&
+              rw_aux_tree(b, t)[idx].offset < offset)
+               idx++;
 
-               if (rw_aux_tree(b, t)[m].offset < offset)
-                       l = m + 1;
-               else
-                       r = m;
-       }
+       while (idx &&
+              rw_aux_tree(b, t)[idx - 1].offset >= offset)
+               idx--;
 
-       EBUG_ON(l < t->size &&
-               rw_aux_tree(b, t)[l].offset < offset);
-       EBUG_ON(l &&
-               rw_aux_tree(b, t)[l - 1].offset >= offset);
-
-       EBUG_ON(l > r);
-       EBUG_ON(l > t->size);
+       EBUG_ON(idx < t->size &&
+               rw_aux_tree(b, t)[idx].offset < offset);
+       EBUG_ON(idx && rw_aux_tree(b, t)[idx - 1].offset >= offset);
+       EBUG_ON(idx + 1 < t->size &&
+               rw_aux_tree(b, t)[idx].offset ==
+               rw_aux_tree(b, t)[idx + 1].offset);
 
-       return l;
+       return idx;
 }
 
 static inline unsigned bfloat_mantissa(const struct bkey_float *f,
@@ -1150,13 +1152,9 @@ static void bch2_bset_fix_lookup_table(struct btree *b,
        if (!bset_has_rw_aux_tree(t))
                return;
 
+       /* returns first entry >= where */
        l = rw_aux_tree_bsearch(b, t, where);
 
-       /* l is first >= than @where */
-
-       EBUG_ON(l < t->size && rw_aux_tree(b, t)[l].offset < where);
-       EBUG_ON(l && rw_aux_tree(b, t)[l - 1].offset >= where);
-
        if (!l) /* never delete first entry */
                l++;
        else if (l < t->size &&

diff --git a/fs/bcachefs/btree_types.h b/fs/bcachefs/btree_types.h
index 2ca3b1f0236f86abc250e9bcb6f60008699f1abf..fcd660470e52181950514d11da5cb65fba846707 100644 (file)
--- a/fs/bcachefs/btree_types.h
+++ b/fs/bcachefs/btree_types.h
@@ -371,6 +371,11 @@ __btree_node_offset_to_key(const struct btree *b, u16 k)
        return (void *) ((u64 *) b->data + k + 1);
 }
 
+static inline unsigned btree_bkey_first_offset(const struct bset_tree *t)
+{
+       return t->data_offset + offsetof(struct bset, _data) / sizeof(u64);
+}
+
 #define btree_bkey_first(_b, _t)       (bset(_b, _t)->start)
 
 #define btree_bkey_last(_b, _t)                                                \