bcachefs: improve checksum error messages

new helpers:
 - bch2_csum_to_text()
 - bch2_csum_err_msg()

standardize our checksum error messages a bit, and print out the
checksums a bit more nicely.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_io.c

@@ -1042,8 +1042,8 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 
 			nonce = btree_nonce(i, b->written << 9);
 
-			csum_bad = bch2_crc_cmp(b->data->csum,
-				csum_vstruct(c, BSET_CSUM_TYPE(i), nonce, b->data));
+			struct bch_csum csum = csum_vstruct(c, BSET_CSUM_TYPE(i), nonce, b->data);
+			csum_bad = bch2_crc_cmp(b->data->csum, csum);
 			if (csum_bad)
 				bch2_io_error(ca, BCH_MEMBER_ERROR_checksum);
 
@@ -1051,7 +1051,10 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 				     -BCH_ERR_btree_node_read_err_want_retry,
 				     c, ca, b, i,
 				     bset_bad_csum,
-				     "invalid checksum");
+				     "%s",
+				     (printbuf_reset(&buf),
+				      bch2_csum_err_msg(&buf, BSET_CSUM_TYPE(i), b->data->csum, csum),
+				      buf.buf));
 
 			ret = bset_encrypt(c, i, b->written << 9);
 			if (bch2_fs_fatal_err_on(ret, c,
@@ -1080,8 +1083,8 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 				     "unknown checksum type %llu", BSET_CSUM_TYPE(i));
 
 			nonce = btree_nonce(i, b->written << 9);
-			csum_bad = bch2_crc_cmp(bne->csum,
-				csum_vstruct(c, BSET_CSUM_TYPE(i), nonce, bne));
+			struct bch_csum csum = csum_vstruct(c, BSET_CSUM_TYPE(i), nonce, bne);
+			csum_bad = bch2_crc_cmp(bne->csum, csum);
 			if (csum_bad)
 				bch2_io_error(ca, BCH_MEMBER_ERROR_checksum);
 
@@ -1089,7 +1092,10 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 				     -BCH_ERR_btree_node_read_err_want_retry,
 				     c, ca, b, i,
 				     bset_bad_csum,
-				     "invalid checksum");
+				     "%s",
+				     (printbuf_reset(&buf),
+				      bch2_csum_err_msg(&buf, BSET_CSUM_TYPE(i), bne->csum, csum),
+				      buf.buf));
 
 			ret = bset_encrypt(c, i, b->written << 9);
 			if (bch2_fs_fatal_err_on(ret, c,

fs/bcachefs/checksum.h

@@ -45,6 +45,29 @@ struct bch_csum bch2_checksum(struct bch_fs *, unsigned, struct nonce,
 	bch2_checksum(_c, _type, _nonce, _start, vstruct_end(_i) - _start);\
 })
 
+static inline void bch2_csum_to_text(struct printbuf *out,
+				     enum bch_csum_type type,
+				     struct bch_csum csum)
+{
+	const u8 *p = (u8 *) &csum;
+	unsigned bytes = type < BCH_CSUM_NR ? bch_crc_bytes[type] : 16;
+
+	for (unsigned i = 0; i < bytes; i++)
+		prt_hex_byte(out, p[i]);
+}
+
+static inline void bch2_csum_err_msg(struct printbuf *out,
+				     enum bch_csum_type type,
+				     struct bch_csum expected,
+				     struct bch_csum got)
+{
+	prt_printf(out, "checksum error: got ");
+	bch2_csum_to_text(out, type, got);
+	prt_str(out, " should be ");
+	bch2_csum_to_text(out, type, expected);
+	prt_printf(out, " type %s", bch2_csum_types[type]);
+}
+
 int bch2_chacha_encrypt_key(struct bch_key *, struct nonce, void *, size_t);
 int bch2_request_key(struct bch_sb *, struct bch_key *);
 #ifndef __KERNEL__

fs/bcachefs/io_read.c

@@ -642,12 +642,17 @@ static void __bch2_read_endio(struct work_struct *work)
 		goto out;
 	}
 
+	struct printbuf buf = PRINTBUF;
+	buf.atomic++;
+	prt_str(&buf, "data ");
+	bch2_csum_err_msg(&buf, crc.csum_type, rbio->pick.crc.csum, csum);
+
 	bch_err_inum_offset_ratelimited(ca,
 		rbio->read_pos.inode,
 		rbio->read_pos.offset << 9,
-		"data checksum error: expected %0llx:%0llx got %0llx:%0llx (type %s)",
-		rbio->pick.crc.csum.hi, rbio->pick.crc.csum.lo,
-		csum.hi, csum.lo, bch2_csum_types[crc.csum_type]);
+		"data %s", buf.buf);
+	printbuf_exit(&buf);
+
 	bch2_io_error(ca, BCH_MEMBER_ERROR_checksum);
 	bch2_rbio_error(rbio, READ_RETRY_AVOID, BLK_STS_IOERR);
 	goto out;

fs/bcachefs/journal_io.c

@@ -27,11 +27,15 @@ static struct nonce journal_nonce(const struct jset *jset)
 	}};
 }
 
-static bool jset_csum_good(struct bch_fs *c, struct jset *j)
+static bool jset_csum_good(struct bch_fs *c, struct jset *j, struct bch_csum *csum)
 {
-	return bch2_checksum_type_valid(c, JSET_CSUM_TYPE(j)) &&
-		!bch2_crc_cmp(j->csum,
-			      csum_vstruct(c, JSET_CSUM_TYPE(j), journal_nonce(j), j));
+	if (!bch2_checksum_type_valid(c, JSET_CSUM_TYPE(j))) {
+		*csum = (struct bch_csum) {};
+		return false;
+	}
+
+	*csum = csum_vstruct(c, JSET_CSUM_TYPE(j), journal_nonce(j), j);
+	return !bch2_crc_cmp(j->csum, *csum);
 }
 
 static inline u32 journal_entry_radix_idx(struct bch_fs *c, u64 seq)
@@ -934,6 +938,7 @@ static int journal_read_bucket(struct bch_dev *ca,
 	u64 offset = bucket_to_sector(ca, ja->buckets[bucket]),
 	    end = offset + ca->mi.bucket_size;
 	bool saw_bad = false, csum_good;
+	struct printbuf err = PRINTBUF;
 	int ret = 0;
 
 	pr_debug("reading %u", bucket);
@@ -966,7 +971,7 @@ static int journal_read_bucket(struct bch_dev *ca,
 				 * found on a different device, and missing or
 				 * no journal entries will be handled later
 				 */
-				return 0;
+				goto out;
 			}
 
 			j = buf->data;
@@ -983,12 +988,12 @@ static int journal_read_bucket(struct bch_dev *ca,
 				ret = journal_read_buf_realloc(buf,
 							vstruct_bytes(j));
 				if (ret)
-					return ret;
+					goto err;
 			}
 			goto reread;
 		case JOURNAL_ENTRY_NONE:
 			if (!saw_bad)
-				return 0;
+				goto out;
 			/*
 			 * On checksum error we don't really trust the size
 			 * field of the journal entry we read, so try reading
@@ -997,7 +1002,7 @@ static int journal_read_bucket(struct bch_dev *ca,
 			sectors = block_sectors(c);
 			goto next_block;
 		default:
-			return ret;
+			goto err;
 		}
 
 		/*
@@ -1007,20 +1012,28 @@ static int journal_read_bucket(struct bch_dev *ca,
 		 * bucket:
 		 */
 		if (le64_to_cpu(j->seq) < ja->bucket_seq[bucket])
-			return 0;
+			goto out;
 
 		ja->bucket_seq[bucket] = le64_to_cpu(j->seq);
 
-		csum_good = jset_csum_good(c, j);
+		enum bch_csum_type csum_type = JSET_CSUM_TYPE(j);
+		struct bch_csum csum;
+		csum_good = jset_csum_good(c, j, &csum);
+
 		if (bch2_dev_io_err_on(!csum_good, ca, BCH_MEMBER_ERROR_checksum,
-				       "journal checksum error"))
+				       "%s",
+				       (printbuf_reset(&err),
+					prt_str(&err, "journal "),
+					bch2_csum_err_msg(&err, csum_type, j->csum, csum),
+					err.buf)))
 			saw_bad = true;
 
 		ret = bch2_encrypt(c, JSET_CSUM_TYPE(j), journal_nonce(j),
 			     j->encrypted_start,
 			     vstruct_end(j) - (void *) j->encrypted_start);
 		bch2_fs_fatal_err_on(ret, c,
-				"error decrypting journal entry: %i", ret);
+				"error decrypting journal entry: %s",
+				bch2_err_str(ret));
 
 		mutex_lock(&jlist->lock);
 		ret = journal_entry_add(c, ca, (struct journal_ptr) {
@@ -1039,7 +1052,7 @@ static int journal_read_bucket(struct bch_dev *ca,
 		case JOURNAL_ENTRY_ADD_OUT_OF_RANGE:
 			break;
 		default:
-			return ret;
+			goto err;
 		}
 next_block:
 		pr_debug("next");
@@ -1048,7 +1061,11 @@ static int journal_read_bucket(struct bch_dev *ca,
 		j = ((void *) j) + (sectors << 9);
 	}
 
-	return 0;
+out:
+	ret = 0;
+err:
+	printbuf_exit(&err);
+	return ret;
 }
 
 static CLOSURE_CALLBACK(bch2_journal_read_device)

fs/bcachefs/super-io.c

@@ -612,7 +612,6 @@ int bch2_sb_from_fs(struct bch_fs *c, struct bch_dev *ca)
 
 static int read_one_super(struct bch_sb_handle *sb, u64 offset, struct printbuf *err)
 {
-	struct bch_csum csum;
 	size_t bytes;
 	int ret;
 reread:
@@ -653,17 +652,16 @@ static int read_one_super(struct bch_sb_handle *sb, u64 offset, struct printbuf
 		goto reread;
 	}
 
-	if (BCH_SB_CSUM_TYPE(sb->sb) >= BCH_CSUM_NR) {
+	enum bch_csum_type csum_type = BCH_SB_CSUM_TYPE(sb->sb);
+	if (csum_type >= BCH_CSUM_NR) {
 		prt_printf(err, "unknown checksum type %llu", BCH_SB_CSUM_TYPE(sb->sb));
 		return -BCH_ERR_invalid_sb_csum_type;
 	}
 
 	/* XXX: verify MACs */
-	csum = csum_vstruct(NULL, BCH_SB_CSUM_TYPE(sb->sb),
-			    null_nonce(), sb->sb);
-
+	struct bch_csum csum = csum_vstruct(NULL, csum_type, null_nonce(), sb->sb);
 	if (bch2_crc_cmp(csum, sb->sb->csum)) {
-		prt_printf(err, "bad checksum");
+		bch2_csum_err_msg(err, csum_type, sb->sb->csum, csum);
 		return -BCH_ERR_invalid_sb_csum;
 	}