bcache: Don't touch bucket gen for dirty ptrs

Unnecessary since a bucket that has dirty pointers pointing to it can
never be invalidated - and skipping it is a measurable performance
boost, since the bucket gen will usually be a cache miss.

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

2 files changed, 7 insertions, 2 deletions

diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c
index 16958704af3b..e51a739f7514 100644
--- a/drivers/md/bcache/bset.c
+++ b/drivers/md/bcache/bset.c
@@ -176,10 +176,14 @@ bool bch_ptr_bad(struct btree *b, const struct bkey *k)
             bch_ptr_invalid(b, k))
                 return true;
 
-        for (i = 0; i < KEY_PTRS(k); i++) {
+        for (i = 0; i < KEY_PTRS(k); i++)
                 if (!ptr_available(b->c, k, i))
                         return true;
 
+        if (!expensive_debug_checks(b->c) && KEY_DIRTY(k))
+                return false;
+
+        for (i = 0; i < KEY_PTRS(k); i++) {
                 g = PTR_BUCKET(b->c, k, i);
                 stale = ptr_stale(b->c, k, i);
 
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 5878cdb39529..59b3d6df100b 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -630,7 +630,8 @@ static void bch_cache_read_endio(struct bio *bio, int error)
 
         if (error)
                 s->iop.error = error;
-        else if (ptr_stale(s->iop.c, &b->key, 0)) {
+        else if (!KEY_DIRTY(&b->key) &&
+                 ptr_stale(s->iop.c, &b->key, 0)) {
                 atomic_long_inc(&s->iop.c->cache_read_races);
                 s->iop.error = -EINTR;
         }