bcachefs: Also print out in-memory gen on stale dirty pointer

We're trying to track down a bug that shows itself as newly-created
extents having stale dirty pointers - possibly due to the in memory gen
and the btree gen being inconsistent. This patch changes the error
message to also print out the in memory bucket gen when this happens.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/buckets.c

@@ -699,49 +699,51 @@ static int check_bucket_ref(struct bch_fs *c,
 			    struct bkey_s_c k,
 			    const struct bch_extent_ptr *ptr,
 			    s64 sectors, enum bch_data_type ptr_data_type,
-			    u8 bucket_gen, u8 bucket_data_type,
+			    u8 b_gen, u8 bucket_data_type,
 			    u16 dirty_sectors, u16 cached_sectors)
 {
-	size_t bucket_nr = PTR_BUCKET_NR(bch_dev_bkey_exists(c, ptr->dev), ptr);
+	struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
+	size_t bucket_nr = PTR_BUCKET_NR(ca, ptr);
 	u16 bucket_sectors = !ptr->cached
 		? dirty_sectors
 		: cached_sectors;
 	char buf[200];
 
-	if (gen_after(ptr->gen, bucket_gen)) {
+	if (gen_after(ptr->gen, b_gen)) {
 		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
 			"bucket %u:%zu gen %u data type %s: ptr gen %u newer than bucket gen\n"
 			"while marking %s",
-			ptr->dev, bucket_nr, bucket_gen,
+			ptr->dev, bucket_nr, b_gen,
 			bch2_data_types[bucket_data_type ?: ptr_data_type],
 			ptr->gen,
 			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));
 		return -EIO;
 	}
 
-	if (gen_cmp(bucket_gen, ptr->gen) > BUCKET_GC_GEN_MAX) {
+	if (gen_cmp(b_gen, ptr->gen) > BUCKET_GC_GEN_MAX) {
 		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
 			"bucket %u:%zu gen %u data type %s: ptr gen %u too stale\n"
 			"while marking %s",
-			ptr->dev, bucket_nr, bucket_gen,
+			ptr->dev, bucket_nr, b_gen,
 			bch2_data_types[bucket_data_type ?: ptr_data_type],
 			ptr->gen,
 			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));
 		return -EIO;
 	}
 
-	if (bucket_gen != ptr->gen && !ptr->cached) {
+	if (b_gen != ptr->gen && !ptr->cached) {
 		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
-			"bucket %u:%zu gen %u data type %s: stale dirty ptr (gen %u)\n"
+			"bucket %u:%zu gen %u (mem gen %u) data type %s: stale dirty ptr (gen %u)\n"
 			"while marking %s",
-			ptr->dev, bucket_nr, bucket_gen,
+			ptr->dev, bucket_nr, b_gen,
+			*bucket_gen(ca, bucket_nr),
 			bch2_data_types[bucket_data_type ?: ptr_data_type],
 			ptr->gen,
 			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));
 		return -EIO;
 	}
 
-	if (bucket_gen != ptr->gen)
+	if (b_gen != ptr->gen)
 		return 1;
 
 	if (bucket_data_type && ptr_data_type &&
@@ -749,7 +751,7 @@ static int check_bucket_ref(struct bch_fs *c,
 		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
 			"bucket %u:%zu gen %u different types of data in same bucket: %s, %s\n"
 			"while marking %s",
-			ptr->dev, bucket_nr, bucket_gen,
+			ptr->dev, bucket_nr, b_gen,
 			bch2_data_types[bucket_data_type],
 			bch2_data_types[ptr_data_type],
 			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));
@@ -760,7 +762,7 @@ static int check_bucket_ref(struct bch_fs *c,
 		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
 			"bucket %u:%zu gen %u data type %s sector count overflow: %u + %lli > U16_MAX\n"
 			"while marking %s",
-			ptr->dev, bucket_nr, bucket_gen,
+			ptr->dev, bucket_nr, b_gen,
 			bch2_data_types[bucket_data_type ?: ptr_data_type],
 			bucket_sectors, sectors,
 			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));