bcache: PRECEDING_KEY()

[linux-2.6-block.git] / drivers / md / bcache / bset.h

diff --git a/drivers/md/bcache/bset.h b/drivers/md/bcache/bset.h
index e67386001814bde493c9fd038f7d6e9df2e3e969..bc9975526aa15fbef5781cb9e93c3ff7de765acf 100644 (file)
--- 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 *);