bcachefs: Simplify resuming of journal position

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

fs/bcachefs/journal_io.c

@@ -1089,6 +1089,13 @@ static int journal_read_bucket(struct bch_dev *ca,
 			goto err;
 		}
 
+		if (le64_to_cpu(j->seq) > ja->highest_seq_found) {
+			ja->highest_seq_found = le64_to_cpu(j->seq);
+			ja->cur_idx = bucket;
+			ja->sectors_free = ca->mi.bucket_size -
+				bucket_remainder(ca, offset) - sectors;
+		}
+
 		/*
 		 * This happens sometimes if we don't have discards on -
 		 * when we've partially overwritten a bucket with new
@@ -1157,8 +1164,6 @@ static CLOSURE_CALLBACK(bch2_journal_read_device)
 	struct bch_fs *c = ca->fs;
 	struct journal_list *jlist =
 		container_of(cl->parent, struct journal_list, cl);
-	struct journal_replay *r, **_r;
-	struct genradix_iter iter;
 	struct journal_read_buf buf = { NULL, 0 };
 	unsigned i;
 	int ret = 0;
@@ -1178,47 +1183,6 @@ static CLOSURE_CALLBACK(bch2_journal_read_device)
 			goto err;
 	}
 
-	ja->sectors_free = ca->mi.bucket_size;
-
-	mutex_lock(&jlist->lock);
-	genradix_for_each_reverse(&c->journal_entries, iter, _r) {
-		r = *_r;
-
-		if (!r)
-			continue;
-
-		darray_for_each(r->ptrs, i)
-			if (i->dev == ca->dev_idx) {
-				unsigned wrote = bucket_remainder(ca, i->sector) +
-					vstruct_sectors(&r->j, c->block_bits);
-
-				ja->cur_idx = i->bucket;
-				ja->sectors_free = ca->mi.bucket_size - wrote;
-				goto found;
-			}
-	}
-found:
-	mutex_unlock(&jlist->lock);
-
-	if (ja->bucket_seq[ja->cur_idx] &&
-	    ja->sectors_free == ca->mi.bucket_size) {
-#if 0
-		/*
-		 * Debug code for ZNS support, where we (probably) want to be
-		 * correlated where we stopped in the journal to the zone write
-		 * points:
-		 */
-		bch_err(c, "ja->sectors_free == ca->mi.bucket_size");
-		bch_err(c, "cur_idx %u/%u", ja->cur_idx, ja->nr);
-		for (i = 0; i < 3; i++) {
-			unsigned idx = (ja->cur_idx + ja->nr - 1 + i) % ja->nr;
-
-			bch_err(c, "bucket_seq[%u] = %llu", idx, ja->bucket_seq[idx]);
-		}
-#endif
-		ja->sectors_free = 0;
-	}
-
 	/*
 	 * Set dirty_idx to indicate the entire journal is full and needs to be
 	 * reclaimed - journal reclaim will immediately reclaim whatever isn't

fs/bcachefs/journal_types.h

@@ -327,6 +327,7 @@ struct journal_device {
 
 	/* for bch_journal_read_device */
 	struct closure		read;
+	u64			highest_seq_found;
 };
 
 /*