bcachefs: Fix marking reflink pointers to missing indirect extents

reflink pointers to missing indirect extents aren't deleted, they just
have an error bit set - in case the indirect extent somehow reappears.

fsck/mark and sweep thus needs to ignore these errors.

Also, they can be marked AUTOFIX now.

Reported-by: Roland Vet <vet.roland@protonmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Author: Kent Overstreet

fs/bcachefs/reflink.c

@@ -381,6 +381,8 @@ static s64 gc_trigger_reflink_p_segment(struct btree_trans *trans,
 not_found:
 	if (flags & BTREE_TRIGGER_check_repair) {
 		ret = bch2_indirect_extent_missing_error(trans, p, *idx, next_idx, false);
+		if (ret == -BCH_ERR_missing_indirect_extent)
+			ret = 0;
 		if (ret)
 			goto err;
 	}

fs/bcachefs/sb-errors_format.h

@@ -180,9 +180,9 @@ enum bch_fsck_flags {
 	x(ptr_crc_nonce_mismatch,				162,	0)		\
 	x(ptr_stripe_redundant,					163,	0)		\
 	x(reservation_key_nr_replicas_invalid,			164,	0)		\
-	x(reflink_v_refcount_wrong,				165,	0)		\
+	x(reflink_v_refcount_wrong,				165,	FSCK_AUTOFIX)	\
 	x(reflink_v_pos_bad,					292,	0)		\
-	x(reflink_p_to_missing_reflink_v,			166,	0)		\
+	x(reflink_p_to_missing_reflink_v,			166,	FSCK_AUTOFIX)	\
 	x(reflink_refcount_underflow,				293,	0)		\
 	x(stripe_pos_bad,					167,	0)		\
 	x(stripe_val_size_bad,					168,	0)		\