3 files changed, 28 insertions, 16 deletions

diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c
index 4a7113236034..7f8a7bd21503 100644
--- a/drivers/md/bcache/bset.c
+++ b/drivers/md/bcache/bset.c
@@ -773,6 +773,33 @@ static void bch_bset_fix_lookup_table(struct btree_keys *b,
                 }
 }
 
+/*
+ * Tries to merge l and r: l should be lower than r
+ * Returns true if we were able to merge. If we did merge, l will be the merged
+ * key, r will be untouched.
+ */
+bool bch_bkey_try_merge(struct btree_keys *b, struct bkey *l, struct bkey *r)
+{
+        if (!b->ops->key_merge)
+                return false;
+
+        /*
+         * Generic header checks
+         * Assumes left and right are in order
+         * Left and right must be exactly aligned
+         */
+        if (KEY_U64s(l) != KEY_U64s(r) ||
+            KEY_DELETED(l) != KEY_DELETED(r) ||
+            KEY_CACHED(l) != KEY_CACHED(r) ||
+            KEY_VERSION(l) != KEY_VERSION(r) ||
+            KEY_CSUM(l) != KEY_CSUM(r) ||
+            bkey_cmp(l, &START_KEY(r)))
+                return false;
+
+        return b->ops->key_merge(b, l, r);
+}
+EXPORT_SYMBOL(bch_bkey_try_merge);
+
 void bch_bset_insert(struct btree_keys *b, struct bkey *where,
                      struct bkey *insert)
 {
diff --git a/drivers/md/bcache/bset.h b/drivers/md/bcache/bset.h
index 759df830bb14..487373057c09 100644
--- a/drivers/md/bcache/bset.h
+++ b/drivers/md/bcache/bset.h
@@ -287,6 +287,7 @@ void bch_btree_keys_init(struct btree_keys *, const struct btree_keys_ops *,
 void bch_bset_init_next(struct btree_keys *, struct bset *, uint64_t);
 void bch_bset_build_written_tree(struct btree_keys *);
 void bch_bset_fix_invalidated_key(struct btree_keys *, struct bkey *);
+bool bch_bkey_try_merge(struct btree_keys *, struct bkey *, struct bkey *);
 void bch_bset_insert(struct btree_keys *, struct bkey *, struct bkey *);
 unsigned bch_btree_insert_key(struct btree_keys *, struct bkey *,
                               struct bkey *);
@@ -299,17 +300,6 @@ enum {
         BTREE_INSERT_STATUS_FRONT_MERGE,
 };
 
-/*
- * Tries to merge l and r: l should be lower than r
- * Returns true if we were able to merge. If we did merge, l will be the merged
- * key, r will be untouched.
- */
-static inline bool bch_bkey_try_merge(struct btree_keys *b,
-                                      struct bkey *l, struct bkey *r)
-{
-        return b->ops->key_merge ?  b->ops->key_merge(b, l, r) : false;
-}
-
 /* Btree key iteration */
 
 struct btree_iter {
diff --git a/drivers/md/bcache/extents.c b/drivers/md/bcache/extents.c
index d6de3c76a87b..7d73d8625522 100644
--- a/drivers/md/bcache/extents.c
+++ b/drivers/md/bcache/extents.c
@@ -575,11 +575,6 @@ static bool bch_extent_merge(struct btree_keys *bk, struct bkey *l, struct bkey
         if (key_merging_disabled(b->c))
                 return false;
 
-        if (KEY_PTRS(l) != KEY_PTRS(r) ||
-            KEY_DIRTY(l) != KEY_DIRTY(r) ||
-            bkey_cmp(l, &START_KEY(r)))
-                return false;
-
         for (i = 0; i < KEY_PTRS(l); i++)
                 if (l->ptr[i] + PTR(0, KEY_SIZE(l), 0) != r->ptr[i] ||
                     PTR_BUCKET_NR(b->c, l, i) != PTR_BUCKET_NR(b->c, r, i))