bcachefs: New backpointers helpers

- bch2_backpointer_del()
- bch2_backpointer_maybe_flush()

Kill a bit of open coding and make sure we're properly handling the
btree write buffer.

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

diff --git a/fs/bcachefs/backpointers.c b/fs/bcachefs/backpointers.c
index 620fa67db7a6cd3f964c554478fbb8b47cf6b4d5..cfd9b9ead473048d319214cd36460d61dc3ea546 100644 (file)
--- a/fs/bcachefs/backpointers.c
+++ b/fs/bcachefs/backpointers.c
@@ -199,6 +199,22 @@ err:
        return ret;
 }
 
+static int bch2_backpointer_del(struct btree_trans *trans, struct bpos pos)
+{
+       return likely(!bch2_backpointers_no_use_write_buffer)
+              ? bch2_btree_delete_at_buffered(trans, BTREE_ID_backpointers, pos)
+              : bch2_btree_delete(trans, BTREE_ID_backpointers, pos, 0);
+}
+
+static int bch2_backpointers_maybe_flush(struct btree_trans *trans,
+                                        struct bkey_s_c visiting_k,
+                                        struct bkey_buf *last_flushed)
+{
+       return likely(!bch2_backpointers_no_use_write_buffer)
+               ? bch2_btree_write_buffer_maybe_flush(trans, visiting_k, last_flushed)
+               : 0;
+}
+
 static void backpointer_target_not_found(struct btree_trans *trans,
                                         struct bkey_s_c_backpointer bp,
                                         struct bkey_s_c target_k)
@@ -300,9 +316,12 @@ err:
        return b;
 }
 
-static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_iter *bp_iter,
-                                       struct bkey_s_c k)
+static int bch2_check_backpointer_has_valid_bucket(struct btree_trans *trans, struct bkey_s_c k,
+                                                  struct bkey_buf *last_flushed)
 {
+       if (k.k->type != KEY_TYPE_backpointer)
+               return 0;
+
        struct bch_fs *c = trans->c;
        struct btree_iter alloc_iter = { NULL };
        struct bkey_s_c alloc_k;
@@ -311,10 +330,14 @@ static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_
 
        struct bpos bucket;
        if (!bp_pos_to_bucket_nodev_noerror(c, k.k->p, &bucket)) {
+               ret = bch2_backpointers_maybe_flush(trans, k, last_flushed);
+               if (ret)
+                       goto out;
+
                if (fsck_err(trans, backpointer_to_missing_device,
                             "backpointer for missing device:\n%s",
                             (bch2_bkey_val_to_text(&buf, c, k), buf.buf)))
-                       ret = bch2_btree_delete_at(trans, bp_iter, 0);
+                       ret = bch2_backpointer_del(trans, k.k->p);
                goto out;
        }
 
@@ -323,13 +346,16 @@ static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_
        if (ret)
                goto out;
 
-       if (fsck_err_on(alloc_k.k->type != KEY_TYPE_alloc_v4,
-                       trans, backpointer_to_missing_alloc,
-                       "backpointer for nonexistent alloc key: %llu:%llu:0\n%s",
-                       alloc_iter.pos.inode, alloc_iter.pos.offset,
-                       (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
-               ret = bch2_btree_delete_at(trans, bp_iter, 0);
-               goto out;
+       if (alloc_k.k->type != KEY_TYPE_alloc_v4) {
+               ret = bch2_backpointers_maybe_flush(trans, k, last_flushed);
+               if (ret)
+                       goto out;
+
+               if (fsck_err(trans, backpointer_to_missing_alloc,
+                            "backpointer for nonexistent alloc key: %llu:%llu:0\n%s",
+                            alloc_iter.pos.inode, alloc_iter.pos.offset,
+                            (bch2_bkey_val_to_text(&buf, c, k), buf.buf)))
+                       ret = bch2_backpointer_del(trans, k.k->p);
        }
 out:
 fsck_err:
@@ -341,11 +367,17 @@ fsck_err:
 /* verify that every backpointer has a corresponding alloc key */
 int bch2_check_btree_backpointers(struct bch_fs *c)
 {
+       struct bkey_buf last_flushed;
+       bch2_bkey_buf_init(&last_flushed);
+       bkey_init(&last_flushed.k->k);
+
        int ret = bch2_trans_run(c,
                for_each_btree_key_commit(trans, iter,
                        BTREE_ID_backpointers, POS_MIN, 0, k,
                        NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
-                 bch2_check_btree_backpointer(trans, &iter, k)));
+                 bch2_check_backpointer_has_valid_bucket(trans, k, &last_flushed)));
+
+       bch2_bkey_buf_exit(&last_flushed, c);
        bch_err_fn(c, ret);
        return ret;
 }
@@ -874,7 +906,7 @@ static int check_one_backpointer(struct btree_trans *trans,
                return ret;
 
        if (!k.k) {
-               ret = bch2_btree_write_buffer_maybe_flush(trans, bp.s_c, last_flushed);
+               ret = bch2_backpointers_maybe_flush(trans, bp.s_c, last_flushed);
                if (ret)
                        goto out;
 
@@ -882,7 +914,7 @@ static int check_one_backpointer(struct btree_trans *trans,
                             "backpointer for missing %s\n  %s",
                             bp.v->level ? "btree node" : "extent",
                             (bch2_bkey_val_to_text(&buf, c, bp.s_c), buf.buf))) {
-                       ret = bch2_btree_delete_at_buffered(trans, BTREE_ID_backpointers, bp.k->p);
+                       ret = bch2_backpointer_del(trans, bp.k->p);
                        goto out;
                }
        }