bcachefs: Fix journal entry repair code

When we detect bad keys in the journal that have to be dropped, the flow
control was wrong - we ended up not checking the next key in that entry.
Oops.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/journal_io.c

@@ -160,6 +160,8 @@ static void journal_entry_null_range(void *start, void *end)
 #define journal_entry_err_on(cond, c, msg, ...)				\
 	((cond) ? journal_entry_err(c, msg, ##__VA_ARGS__) : false)
 
+#define FSCK_DELETED_KEY	5
+
 static int journal_validate_key(struct bch_fs *c, struct jset *jset,
 				struct jset_entry *entry,
 				unsigned level, enum btree_id btree_id,
@@ -172,33 +174,42 @@ static int journal_validate_key(struct bch_fs *c, struct jset *jset,
 	int ret = 0;
 
 	if (journal_entry_err_on(!k->k.u64s, c,
-			"invalid %s in journal entry %llu offset %zi: k->u64s 0",
+			"invalid %s in jset %llu offset %zi/%u entry offset %zi/%u: k->u64s 0",
 			type, le64_to_cpu(jset->seq),
-			(u64 *) entry - jset->_data)) {
+			(u64 *) entry - jset->_data,
+			le32_to_cpu(jset->u64s),
+			(u64 *) k - entry->_data,
+			le16_to_cpu(entry->u64s))) {
 		entry->u64s = cpu_to_le16((u64 *) k - entry->_data);
 		journal_entry_null_range(vstruct_next(entry), next);
-		return 0;
+		return FSCK_DELETED_KEY;
 	}
 
 	if (journal_entry_err_on((void *) bkey_next(k) >
 				(void *) vstruct_next(entry), c,
-			"invalid %s in journal entry %llu offset %zi: extends past end of journal entry",
+			"invalid %s in jset %llu offset %zi/%u entry offset %zi/%u: extends past end of journal entry",
 			type, le64_to_cpu(jset->seq),
-			(u64 *) entry - jset->_data)) {
+			(u64 *) entry - jset->_data,
+			le32_to_cpu(jset->u64s),
+			(u64 *) k - entry->_data,
+			le16_to_cpu(entry->u64s))) {
 		entry->u64s = cpu_to_le16((u64 *) k - entry->_data);
 		journal_entry_null_range(vstruct_next(entry), next);
-		return 0;
+		return FSCK_DELETED_KEY;
 	}
 
 	if (journal_entry_err_on(k->k.format != KEY_FORMAT_CURRENT, c,
-			"invalid %s in journal entry %llu offset %zi: bad format %u",
+			"invalid %s in jset %llu offset %zi/%u entry offset %zi/%u: bad format %u",
 			type, le64_to_cpu(jset->seq),
 			(u64 *) entry - jset->_data,
+			le32_to_cpu(jset->u64s),
+			(u64 *) k - entry->_data,
+			le16_to_cpu(entry->u64s),
 			k->k.format)) {
-		le16_add_cpu(&entry->u64s, -k->k.u64s);
+		le16_add_cpu(&entry->u64s, -((u16) k->k.u64s));
 		memmove(k, bkey_next(k), next - (void *) bkey_next(k));
 		journal_entry_null_range(vstruct_next(entry), next);
-		return 0;
+		return FSCK_DELETED_KEY;
 	}
 
 	if (!write)
@@ -212,15 +223,18 @@ static int journal_validate_key(struct bch_fs *c, struct jset *jset,
 		char buf[160];
 
 		bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(k));
-		mustfix_fsck_err(c, "invalid %s in journal entry %llu offset %zi: %s\n%s",
+		mustfix_fsck_err(c, "invalid %s in jset %llu offset %zi/%u entry offset %zi/%u: %s\n%s",
 				 type, le64_to_cpu(jset->seq),
 				 (u64 *) entry - jset->_data,
+				 le32_to_cpu(jset->u64s),
+				 (u64 *) k - entry->_data,
+				 le16_to_cpu(entry->u64s),
 				 invalid, buf);
 
-		le16_add_cpu(&entry->u64s, -k->k.u64s);
+		le16_add_cpu(&entry->u64s, -((u16) k->k.u64s));
 		memmove(k, bkey_next(k), next - (void *) bkey_next(k));
 		journal_entry_null_range(vstruct_next(entry), next);
-		return 0;
+		return FSCK_DELETED_KEY;
 	}
 
 	if (write)
@@ -236,15 +250,17 @@ static int journal_entry_validate_btree_keys(struct bch_fs *c,
 					     struct jset_entry *entry,
 					     int write)
 {
-	struct bkey_i *k;
+	struct bkey_i *k = entry->start;
 
-	vstruct_for_each(entry, k) {
+	while (k != vstruct_last(entry)) {
 		int ret = journal_validate_key(c, jset, entry,
 					       entry->level,
 					       entry->btree_id,
 					       k, "key", write);
-		if (ret)
-			return ret;
+		if (ret == FSCK_DELETED_KEY)
+			continue;
+
+		k = bkey_next(k);
 	}
 
 	return 0;