bcachefs: Fix gc of stale ptr gens

Awhile back, gcing of stale pointers was split out from full
mark-and-sweep gc - but, the bit to actually drop those stale pointers
wasn't implemnted. Whoops.

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

diff --git a/fs/bcachefs/btree_gc.c b/fs/bcachefs/btree_gc.c
index 4b20817402f6b6f824910ee685425f9f05fa785c..2774f10054a928843a24f853092d24e81bf10aef 100644 (file)
--- a/fs/bcachefs/btree_gc.c
+++ b/fs/bcachefs/btree_gc.c
@@ -8,6 +8,7 @@
 #include "alloc_background.h"
 #include "alloc_foreground.h"
 #include "bkey_methods.h"
+#include "bkey_on_stack.h"
 #include "btree_locking.h"
 #include "btree_update_interior.h"
 #include "btree_io.h"
@@ -890,40 +891,77 @@ out:
        return ret;
 }
 
+static bool gc_btree_gens_key(struct bch_fs *c, struct bkey_s_c k)
+{
+       struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+       const struct bch_extent_ptr *ptr;
+
+       percpu_down_read(&c->mark_lock);
+       bkey_for_each_ptr(ptrs, ptr) {
+               struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
+               struct bucket *g = PTR_BUCKET(ca, ptr, false);
+
+               if (gen_after(g->mark.gen, ptr->gen) > 16) {
+                       percpu_up_read(&c->mark_lock);
+                       return true;
+               }
+       }
+
+       bkey_for_each_ptr(ptrs, ptr) {
+               struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
+               struct bucket *g = PTR_BUCKET(ca, ptr, false);
+
+               if (gen_after(g->gc_gen, ptr->gen))
+                       g->gc_gen = ptr->gen;
+       }
+       percpu_up_read(&c->mark_lock);
+
+       return false;
+}
+
 /*
  * For recalculating oldest gen, we only need to walk keys in leaf nodes; btree
  * node pointers currently never have cached pointers that can become stale:
  */
-static int bch2_gc_btree_gens(struct bch_fs *c, enum btree_id id)
+static int bch2_gc_btree_gens(struct bch_fs *c, enum btree_id btree_id)
 {
        struct btree_trans trans;
        struct btree_iter *iter;
        struct bkey_s_c k;
-       int ret;
+       struct bkey_on_stack sk;
+       int ret = 0;
 
+       bkey_on_stack_init(&sk);
        bch2_trans_init(&trans, c, 0, 0);
 
-       for_each_btree_key(&trans, iter, id, POS_MIN, BTREE_ITER_PREFETCH, k, ret) {
-               struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
-               const struct bch_extent_ptr *ptr;
+       iter = bch2_trans_get_iter(&trans, btree_id, POS_MIN,
+                                  BTREE_ITER_PREFETCH);
 
-               percpu_down_read(&c->mark_lock);
-               bkey_for_each_ptr(ptrs, ptr) {
-                       struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
-                       struct bucket *g = PTR_BUCKET(ca, ptr, false);
+       while ((k = bch2_btree_iter_peek(iter)).k &&
+              !(ret = bkey_err(k))) {
+               if (gc_btree_gens_key(c, k)) {
+                       bkey_on_stack_reassemble(&sk, c, k);
+                       bch2_extent_normalize(c, bkey_i_to_s(sk.k));
 
-                       if (gen_after(g->gc_gen, ptr->gen))
-                               g->gc_gen = ptr->gen;
+                       bch2_btree_iter_set_pos(iter, bkey_start_pos(&sk.k->k));
 
-                       if (gen_after(g->mark.gen, ptr->gen) > 32) {
-                               /* rewrite btree node */
+                       bch2_trans_update(&trans, iter, sk.k, 0);
 
+                       ret = bch2_trans_commit(&trans, NULL, NULL,
+                                               BTREE_INSERT_NOFAIL);
+                       if (ret == -EINTR)
+                               continue;
+                       if (ret) {
+                               break;
                        }
                }
-               percpu_up_read(&c->mark_lock);
+
+               bch2_btree_iter_next(iter);
        }
 
        bch2_trans_exit(&trans);
+       bkey_on_stack_exit(&sk, c);
+
        return ret;
 }