bcachefs: Add an .invalid method for bch2_btree_ptr_v2

It was using the method for btree_ptr_v1, but that wasn't checking all
the fields.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/extents.c

@@ -157,7 +157,7 @@ int bch2_bkey_pick_read_device(struct bch_fs *c, struct bkey_s_c k,
 
 const char *bch2_btree_ptr_invalid(const struct bch_fs *c, struct bkey_s_c k)
 {
-	if (bkey_val_u64s(k.k) > BKEY_BTREE_PTR_VAL_U64s_MAX)
+	if (bkey_val_u64s(k.k) > BCH_REPLICAS_MAX)
 		return "value too big";
 
 	return bch2_bkey_ptrs_invalid(c, k);
@@ -169,6 +169,22 @@ void bch2_btree_ptr_to_text(struct printbuf *out, struct bch_fs *c,
 	bch2_bkey_ptrs_to_text(out, c, k);
 }
 
+const char *bch2_btree_ptr_v2_invalid(const struct bch_fs *c, struct bkey_s_c k)
+{
+	struct bkey_s_c_btree_ptr_v2 bp = bkey_s_c_to_btree_ptr_v2(k);
+
+	if (bkey_val_bytes(k.k) <= sizeof(*bp.v))
+		return "value too small";
+
+	if (bkey_val_u64s(k.k) > BKEY_BTREE_PTR_VAL_U64s_MAX)
+		return "value too big";
+
+	if (bp.v->min_key.snapshot)
+		return "invalid min_key.snapshot";
+
+	return bch2_bkey_ptrs_invalid(c, k);
+}
+
 void bch2_btree_ptr_v2_to_text(struct printbuf *out, struct bch_fs *c,
 			    struct bkey_s_c k)
 {

fs/bcachefs/extents.h

@@ -371,6 +371,7 @@ const char *bch2_btree_ptr_invalid(const struct bch_fs *, struct bkey_s_c);
 void bch2_btree_ptr_to_text(struct printbuf *, struct bch_fs *,
 			    struct bkey_s_c);
 
+const char *bch2_btree_ptr_v2_invalid(const struct bch_fs *, struct bkey_s_c);
 void bch2_btree_ptr_v2_to_text(struct printbuf *, struct bch_fs *,
 			    struct bkey_s_c);
 void bch2_btree_ptr_v2_compat(enum btree_id, unsigned, unsigned,
@@ -383,7 +384,7 @@ void bch2_btree_ptr_v2_compat(enum btree_id, unsigned, unsigned,
 }
 
 #define bch2_bkey_ops_btree_ptr_v2 (struct bkey_ops) {		\
-	.key_invalid	= bch2_btree_ptr_invalid,		\
+	.key_invalid	= bch2_btree_ptr_v2_invalid,		\
 	.val_to_text	= bch2_btree_ptr_v2_to_text,		\
 	.swab		= bch2_ptr_swab,			\
 	.compat		= bch2_btree_ptr_v2_compat,		\