bcachefs: Have fsck check for stripe pointers matching stripe

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

fs/bcachefs/btree_gc.c

@@ -223,6 +223,11 @@ static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
 					"pointer to nonexistent stripe %llu",
 					(u64) p.ec.idx))
 				do_update = true;
+
+			if (fsck_err_on(!bch2_ptr_matches_stripe_m(m, p), c,
+					"pointer does not match stripe %llu",
+					(u64) p.ec.idx))
+				do_update = true;
 		}
 	}
 
@@ -274,8 +279,22 @@ static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
 				if (extent_entry_type(entry) == BCH_EXTENT_ENTRY_stripe_ptr) {
 					struct stripe *m = genradix_ptr(&c->stripes[true],
 									entry->stripe_ptr.idx);
+					union bch_extent_entry *next_ptr;
+
+					bkey_extent_entry_for_each_from(ptrs, next_ptr, entry)
+						if (extent_entry_type(next_ptr) == BCH_EXTENT_ENTRY_ptr)
+							goto found;
+					next_ptr = NULL;
+found:
+					if (!next_ptr) {
+						bch_err(c, "aieee, found stripe ptr with no data ptr");
+						continue;
+					}
 
-					if (!m || !m->alive) {
+					if (!m || !m->alive ||
+					    !__bch2_ptr_matches_stripe(&m->ptrs[entry->stripe_ptr.block],
+								       &next_ptr->ptr,
+								       m->sectors)) {
 						bch2_bkey_extent_entry_drop(new, entry);
 						goto again;
 					}

fs/bcachefs/buckets.c

@@ -1215,6 +1215,8 @@ static int bch2_mark_stripe(struct bch_fs *c,
 			m->block_sectors[i] =
 				stripe_blockcount_get(new_s, i);
 			m->blocks_nonempty += !!m->block_sectors[i];
+
+			m->ptrs[i] = new_s->ptrs[i];
 		}
 
 		bch2_bkey_to_replicas(&m->r.e, new);

fs/bcachefs/ec.c

@@ -151,7 +151,8 @@ static int bkey_matches_stripe(struct bch_stripe *s,
 
 	bkey_for_each_ptr(ptrs, ptr)
 		for (i = 0; i < nr_data; i++)
-			if (__bch2_ptr_matches_stripe(s, ptr, i))
+			if (__bch2_ptr_matches_stripe(&s->ptrs[i], ptr,
+						      le16_to_cpu(s->sectors)))
 				return i;
 
 	return -1;

fs/bcachefs/ec.h

@@ -84,27 +84,42 @@ static inline void stripe_csum_set(struct bch_stripe *s,
 	memcpy(stripe_csum(s, block, csum_idx), &csum, bch_crc_bytes[s->csum_type]);
 }
 
-static inline bool __bch2_ptr_matches_stripe(const struct bch_stripe *s,
-					     const struct bch_extent_ptr *ptr,
-					     unsigned block)
+static inline bool __bch2_ptr_matches_stripe(const struct bch_extent_ptr *stripe_ptr,
+					     const struct bch_extent_ptr *data_ptr,
+					     unsigned sectors)
+{
+	return  data_ptr->dev    == stripe_ptr->dev &&
+		data_ptr->gen    == stripe_ptr->gen &&
+		data_ptr->offset >= stripe_ptr->offset &&
+		data_ptr->offset  < stripe_ptr->offset + sectors;
+}
+
+static inline bool bch2_ptr_matches_stripe(const struct bch_stripe *s,
+					   struct extent_ptr_decoded p)
 {
 	unsigned nr_data = s->nr_blocks - s->nr_redundant;
 
-	if (block >= nr_data)
+	BUG_ON(!p.has_ec);
+
+	if (p.ec.block >= nr_data)
 		return false;
 
-	return  ptr->dev    == s->ptrs[block].dev &&
-		ptr->gen    == s->ptrs[block].gen &&
-		ptr->offset >= s->ptrs[block].offset &&
-		ptr->offset  < s->ptrs[block].offset + le16_to_cpu(s->sectors);
+	return __bch2_ptr_matches_stripe(&s->ptrs[p.ec.block], &p.ptr,
+					 le16_to_cpu(s->sectors));
 }
 
-static inline bool bch2_ptr_matches_stripe(const struct bch_stripe *s,
-					   struct extent_ptr_decoded p)
+static inline bool bch2_ptr_matches_stripe_m(const struct stripe *m,
+					     struct extent_ptr_decoded p)
 {
+	unsigned nr_data = m->nr_blocks - m->nr_redundant;
+
 	BUG_ON(!p.has_ec);
 
-	return __bch2_ptr_matches_stripe(s, &p.ptr, p.ec.block);
+	if (p.ec.block >= nr_data)
+		return false;
+
+	return __bch2_ptr_matches_stripe(&m->ptrs[p.ec.block], &p.ptr,
+					 m->sectors);
 }
 
 struct bch_read_bio;

fs/bcachefs/ec_types.h

@@ -22,6 +22,7 @@ struct stripe {
 	unsigned		on_heap:1;
 	u8			blocks_nonempty;
 	u16			block_sectors[BCH_BKEY_PTRS_MAX];
+	struct bch_extent_ptr	ptrs[BCH_BKEY_PTRS_MAX];
 
 	struct bch_replicas_padded r;
 };