bcachefs: Improve bch2_bkey_ptrs_to_text()

Print bucket:offset when the filesystem is online; this makes debugging
easier when correlating with alloc updates.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/extents.c

@@ -953,15 +953,21 @@ void bch2_bkey_ptrs_to_text(struct printbuf *out, struct bch_fs *c,
 		switch (__extent_entry_type(entry)) {
 		case BCH_EXTENT_ENTRY_ptr:
 			ptr = entry_to_ptr(entry);
+			ca = c && ptr->dev < c->sb.nr_devices && c->devs[ptr->dev]
+				? bch_dev_bkey_exists(c, ptr->dev)
+				: NULL;
 
+			if (!ca) {
 				pr_buf(out, "ptr: %u:%llu gen %u%s", ptr->dev,
 				       (u64) ptr->offset, ptr->gen,
 				       ptr->cached ? " cached" : "");
+			} else {
+				u32 offset;
+				u64 b = sector_to_bucket_and_offset(ca, ptr->offset, &offset);
 
-			if (c) {
-				ca = ptr->dev < c->sb.nr_devices && c->devs[ptr->dev]
-					? bch_dev_bkey_exists(c, ptr->dev)
-					: NULL;
+				pr_buf(out, "ptr: %u:%llu:%u gen %u%s", ptr->dev,
+				       b, offset, ptr->gen,
+				       ptr->cached ? " cached" : "");
 
 				if (ca && ptr_stale(ca, ptr))
 					pr_buf(out, " stale");

fs/bcachefs/super.h

@@ -26,6 +26,12 @@ static inline sector_t bucket_remainder(const struct bch_dev *ca, sector_t s)
 	return remainder;
 }
 
+static inline size_t sector_to_bucket_and_offset(const struct bch_dev *ca, sector_t s,
+						 u32 *offset)
+{
+	return div_u64_rem(s, ca->mi.bucket_size, offset);
+}
+
 static inline bool bch2_dev_is_online(struct bch_dev *ca)
 {
 	return !percpu_ref_is_zero(&ca->io_ref);