bcache: PRECEDING_KEY()

btree_insert_key() was open coding this, this is just refactoring.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

2 files changed, 20 insertions, 7 deletions

diff --git a/drivers/md/bcache/bset.h b/drivers/md/bcache/bset.h
index e67386001814..bc9975526aa1 100644
--- a/drivers/md/bcache/bset.h
+++ b/drivers/md/bcache/bset.h
@@ -353,12 +353,30 @@ void bch_bset_fix_lookup_table(struct btree *, struct bkey *);
 struct bkey *__bch_bset_search(struct btree *, struct bset_tree *,
                            const struct bkey *);
 
+/*
+ * Returns the first key that is strictly greater than search
+ */
 static inline struct bkey *bch_bset_search(struct btree *b, struct bset_tree *t,
                                            const struct bkey *search)
 {
         return search ? __bch_bset_search(b, t, search) : t->data->start;
 }
 
+#define PRECEDING_KEY(_k)                                       \
+({                                                              \
+        struct bkey *_ret = NULL;                               \
+                                                                \
+        if (KEY_INODE(_k) || KEY_OFFSET(_k)) {                  \
+                _ret = &KEY(KEY_INODE(_k), KEY_OFFSET(_k), 0);  \
+                                                                \
+                if (!_ret->low)                                 \
+                        _ret->high--;                           \
+                _ret->low--;                                    \
+        }                                                       \
+                                                                \
+        _ret;                                                   \
+})
+
 bool bch_bkey_try_merge(struct btree *, struct bkey *, struct bkey *);
 void bch_btree_sort_lazy(struct btree *);
 void bch_btree_sort_into(struct btree *, struct btree *);
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 7dff73ba1b71..773b0e929ff4 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1844,19 +1844,14 @@ static bool btree_insert_key(struct btree *b, struct btree_op *op,
 
         if (!b->level) {
                 struct btree_iter iter;
-                struct bkey search = KEY(KEY_INODE(k), KEY_START(k), 0);
 
                 /*
                  * bset_search() returns the first key that is strictly greater
                  * than the search key - but for back merging, we want to find
-                 * the first key that is greater than or equal to KEY_START(k) -
-                 * unless KEY_START(k) is 0.
+                 * the previous key.
                  */
-                if (KEY_OFFSET(&search))
-                        SET_KEY_OFFSET(&search, KEY_OFFSET(&search) - 1);
-
                 prev = NULL;
-                m = bch_btree_iter_init(b, &iter, &search);
+                m = bch_btree_iter_init(b, &iter, PRECEDING_KEY(&START_KEY(k)));
 
                 if (fix_overlapping_extents(b, k, &iter, replace_key)) {
                         op->insert_collision = true;