bcachefs: Check for accounting keys with bversion=0

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

Author: Kent Overstreet

fs/bcachefs/bkey.h

@@ -214,9 +214,9 @@ static __always_inline int bversion_cmp(struct bversion l, struct bversion r)
 #define ZERO_VERSION	((struct bversion) { .hi = 0, .lo = 0 })
 #define MAX_VERSION	((struct bversion) { .hi = ~0, .lo = ~0ULL })
 
-static __always_inline int bversion_zero(struct bversion v)
+static __always_inline bool bversion_zero(struct bversion v)
 {
-	return !bversion_cmp(v, ZERO_VERSION);
+	return bversion_cmp(v, ZERO_VERSION) == 0;
 }
 
 #ifdef CONFIG_BCACHEFS_DEBUG

fs/bcachefs/disk_accounting.c

@@ -134,6 +134,10 @@ int bch2_accounting_validate(struct bch_fs *c, struct bkey_s_c k,
 	void *end = &acc_k + 1;
 	int ret = 0;
 
+	bkey_fsck_err_on(bversion_zero(k.k->bversion),
+			 c, accounting_key_version_0,
+			 "accounting key with version=0");
+
 	switch (acc_k.type) {
 	case BCH_DISK_ACCOUNTING_nr_inodes:
 		end = field_end(acc_k, nr_inodes);

fs/bcachefs/sb-errors_format.h

@@ -293,7 +293,8 @@ enum bch_fsck_flags {
 	x(accounting_key_replicas_nr_devs_0,			278,	FSCK_AUTOFIX)	\
 	x(accounting_key_replicas_nr_required_bad,		279,	FSCK_AUTOFIX)	\
 	x(accounting_key_replicas_devs_unsorted,		280,	FSCK_AUTOFIX)	\
-	x(MAX,							282,	0)
+	x(accounting_key_version_0,				282,	FSCK_AUTOFIX)	\
+	x(MAX,							283,	0)
 
 enum bch_sb_error_id {
 #define x(t, n, ...) BCH_FSCK_ERR_##t = n,