bcachefs: btree_ptr_v2

Add a new btree ptr type which contains the sequence number (random 64
bit cookie, actually) for that btree node - this lets us verify that
when we read in a btree node it really is the btree node we wanted.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bcachefs_format.h

@@ -343,7 +343,8 @@ static inline void bkey_init(struct bkey *k)
 	x(stripe,		14)			\
 	x(reflink_p,		15)			\
 	x(reflink_v,		16)			\
-	x(inline_data,		17)
+	x(inline_data,		17)			\
+	x(btree_ptr_v2,		18)
 
 enum bch_bkey_type {
 #define x(name, nr) KEY_TYPE_##name	= nr,
@@ -599,6 +600,19 @@ struct bch_btree_ptr {
 	struct bch_extent_ptr	start[];
 } __attribute__((packed, aligned(8)));
 
+struct bch_btree_ptr_v2 {
+	struct bch_val		v;
+
+	__u64			mem_ptr;
+	__le64			seq;
+	__le16			sectors_written;
+	/* In case we ever decide to do variable size btree nodes: */
+	__le16			sectors;
+	struct bpos		min_key;
+	__u64			_data[0];
+	struct bch_extent_ptr	start[];
+} __attribute__((packed, aligned(8)));
+
 struct bch_extent {
 	struct bch_val		v;
 
@@ -630,7 +644,8 @@ struct bch_reservation {
 
 /* Btree pointers don't carry around checksums: */
 #define BKEY_BTREE_PTR_VAL_U64s_MAX				\
-	((sizeof(struct bch_extent_ptr)) / sizeof(u64) * BCH_REPLICAS_MAX)
+	((sizeof(struct bch_btree_ptr_v2) +			\
+	  sizeof(struct bch_extent_ptr) * BCH_REPLICAS_MAX) / sizeof(u64))
 #define BKEY_BTREE_PTR_U64s_MAX					\
 	(BKEY_U64s + BKEY_BTREE_PTR_VAL_U64s_MAX)
 
@@ -1299,7 +1314,8 @@ LE64_BITMASK(BCH_SB_ERASURE_CODE,	struct bch_sb, flags[3],  0, 16);
 	x(new_siphash,			7)	\
 	x(inline_data,			8)	\
 	x(new_extent_overwrite,		9)	\
-	x(incompressible,		10)
+	x(incompressible,		10)	\
+	x(btree_ptr_v2,			11)
 
 enum bch_sb_feature {
 #define x(f, n) BCH_FEATURE_##f,

fs/bcachefs/bkey.h

@@ -573,6 +573,7 @@ BKEY_VAL_ACCESSORS(stripe);
 BKEY_VAL_ACCESSORS(reflink_p);
 BKEY_VAL_ACCESSORS(reflink_v);
 BKEY_VAL_ACCESSORS(inline_data);
+BKEY_VAL_ACCESSORS(btree_ptr_v2);
 
 /* byte order helpers */
 

fs/bcachefs/btree_cache.h

@@ -40,6 +40,8 @@ static inline u64 btree_ptr_hash_val(const struct bkey_i *k)
 	switch (k->k.type) {
 	case KEY_TYPE_btree_ptr:
 		return *((u64 *) bkey_i_to_btree_ptr_c(k)->v.start);
+	case KEY_TYPE_btree_ptr_v2:
+		return bkey_i_to_btree_ptr_v2_c(k)->v.seq;
 	default:
 		return 0;
 	}

fs/bcachefs/btree_io.c

@@ -734,6 +734,15 @@ static int validate_bset(struct bch_fs *c, struct btree *b,
 			bch2_bpos_swab(&b->data->max_key);
 		}
 
+		if (b->key.k.type == KEY_TYPE_btree_ptr_v2) {
+			struct bch_btree_ptr_v2 *bp =
+				&bkey_i_to_btree_ptr_v2(&b->key)->v;
+
+			btree_err_on(bkey_cmp(b->data->min_key, bp->min_key),
+				     BTREE_ERR_MUST_RETRY, c, b, NULL,
+				     "incorrect min_key");
+		}
+
 		btree_err_on(bkey_cmp(b->data->max_key, b->key.k.p),
 			     BTREE_ERR_MUST_RETRY, c, b, i,
 			     "incorrect max key");
@@ -897,6 +906,15 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct btree *b, bool have_retry
 		     BTREE_ERR_MUST_RETRY, c, b, NULL,
 		     "bad btree header");
 
+	if (b->key.k.type == KEY_TYPE_btree_ptr_v2) {
+		struct bch_btree_ptr_v2 *bp =
+			&bkey_i_to_btree_ptr_v2(&b->key)->v;
+
+		btree_err_on(b->data->keys.seq != bp->seq,
+			     BTREE_ERR_MUST_RETRY, c, b, NULL,
+			     "got wrong btree node");
+	}
+
 	while (b->written < c->opts.btree_node_size) {
 		unsigned sectors, whiteout_u64s = 0;
 		struct nonce nonce;
@@ -1004,15 +1022,15 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct btree *b, bool have_retry
 	i = &b->data->keys;
 	for (k = i->start; k != vstruct_last(i);) {
 		struct bkey tmp;
-		struct bkey_s_c u = bkey_disassemble(b, k, &tmp);
-		const char *invalid = bch2_bkey_val_invalid(c, u);
+		struct bkey_s u = __bkey_disassemble(b, k, &tmp);
+		const char *invalid = bch2_bkey_val_invalid(c, u.s_c);
 
 		if (invalid ||
 		    (inject_invalid_keys(c) &&
 		     !bversion_cmp(u.k->version, MAX_VERSION))) {
 			char buf[160];
 
-			bch2_bkey_val_to_text(&PBUF(buf), c, u);
+			bch2_bkey_val_to_text(&PBUF(buf), c, u.s_c);
 			btree_err(BTREE_ERR_FIXABLE, c, b, i,
 				  "invalid bkey %s: %s", buf, invalid);
 
@@ -1025,6 +1043,12 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct btree *b, bool have_retry
 			continue;
 		}
 
+		if (u.k->type == KEY_TYPE_btree_ptr_v2) {
+			struct bkey_s_btree_ptr_v2 bp = bkey_s_to_btree_ptr_v2(u);
+
+			bp.v->mem_ptr = 0;
+		}
+
 		k = bkey_next_skip_noops(k, vstruct_last(i));
 	}
 

fs/bcachefs/btree_update_interior.c

@@ -332,7 +332,11 @@ static struct btree *__bch2_btree_node_alloc(struct bch_fs *c,
 		goto retry;
 	}
 
-	bkey_btree_ptr_init(&tmp.k);
+	if (c->sb.features & (1ULL << BCH_FEATURE_btree_ptr_v2))
+		bkey_btree_ptr_v2_init(&tmp.k);
+	else
+		bkey_btree_ptr_init(&tmp.k);
+
 	bch2_alloc_sectors_append_ptrs(c, wp, &tmp.k, c->opts.btree_node_size);
 
 	bch2_open_bucket_get(c, wp, &ob);
@@ -354,14 +358,13 @@ static struct btree *bch2_btree_node_alloc(struct btree_update *as, unsigned lev
 {
 	struct bch_fs *c = as->c;
 	struct btree *b;
+	int ret;
 
 	BUG_ON(level >= BTREE_MAX_DEPTH);
 	BUG_ON(!as->reserve->nr);
 
 	b = as->reserve->b[--as->reserve->nr];
 
-	BUG_ON(bch2_btree_node_hash_insert(&c->btree_cache, b, level, as->btree_id));
-
 	set_btree_node_accessed(b);
 	set_btree_node_dirty(b);
 	set_btree_node_need_write(b);
@@ -372,7 +375,16 @@ static struct btree *bch2_btree_node_alloc(struct btree_update *as, unsigned lev
 	b->data->flags = 0;
 	SET_BTREE_NODE_ID(b->data, as->btree_id);
 	SET_BTREE_NODE_LEVEL(b->data, level);
-	b->data->ptr = bkey_i_to_btree_ptr(&b->key)->v.start[0];
+	b->data->ptr = bch2_bkey_ptrs_c(bkey_i_to_s_c(&b->key)).start->ptr;
+
+	if (b->key.k.type == KEY_TYPE_btree_ptr_v2) {
+		struct bkey_i_btree_ptr_v2 *bp = bkey_i_to_btree_ptr_v2(&b->key);
+
+		bp->v.mem_ptr		= 0;
+		bp->v.seq		= b->data->keys.seq;
+		bp->v.sectors_written	= 0;
+		bp->v.sectors		= cpu_to_le16(c->opts.btree_node_size);
+	}
 
 	if (c->sb.features & (1ULL << BCH_FEATURE_new_extent_overwrite))
 		SET_BTREE_NODE_NEW_EXTENT_OVERWRITE(b->data, true);
@@ -385,10 +397,26 @@ static struct btree *bch2_btree_node_alloc(struct btree_update *as, unsigned lev
 
 	btree_node_will_make_reachable(as, b);
 
+	ret = bch2_btree_node_hash_insert(&c->btree_cache, b, level, as->btree_id);
+	BUG_ON(ret);
+
 	trace_btree_node_alloc(c, b);
 	return b;
 }
 
+static void btree_set_min(struct btree *b, struct bpos pos)
+{
+	if (b->key.k.type == KEY_TYPE_btree_ptr_v2)
+		bkey_i_to_btree_ptr_v2(&b->key)->v.min_key = pos;
+	b->data->min_key = pos;
+}
+
+static void btree_set_max(struct btree *b, struct bpos pos)
+{
+	b->key.k.p = pos;
+	b->data->max_key = pos;
+}
+
 struct btree *__bch2_btree_node_alloc_replacement(struct btree_update *as,
 						  struct btree *b,
 						  struct bkey_format format)
@@ -397,11 +425,12 @@ struct btree *__bch2_btree_node_alloc_replacement(struct btree_update *as,
 
 	n = bch2_btree_node_alloc(as, b->c.level);
 
-	n->data->min_key	= b->data->min_key;
-	n->data->max_key	= b->data->max_key;
-	n->data->format		= format;
 	SET_BTREE_NODE_SEQ(n->data, BTREE_NODE_SEQ(b->data) + 1);
 
+	btree_set_min(n, b->data->min_key);
+	btree_set_max(n, b->data->max_key);
+
+	n->data->format		= format;
 	btree_node_set_format(n, format);
 
 	bch2_btree_sort_into(as->c, n, b);
@@ -431,10 +460,9 @@ static struct btree *__btree_root_alloc(struct btree_update *as, unsigned level)
 {
 	struct btree *b = bch2_btree_node_alloc(as, level);
 
-	b->data->min_key = POS_MIN;
-	b->data->max_key = POS_MAX;
+	btree_set_min(b, POS_MIN);
+	btree_set_max(b, POS_MAX);
 	b->data->format = bch2_btree_calc_format(b);
-	b->key.k.p = POS_MAX;
 
 	btree_node_set_format(b, b->data->format);
 	bch2_btree_build_aux_trees(b);
@@ -1263,10 +1291,8 @@ static struct btree *__btree_split_node(struct btree_update *as,
 
 	BUG_ON(!prev);
 
-	n1->key.k.p = bkey_unpack_pos(n1, prev);
-	n1->data->max_key = n1->key.k.p;
-	n2->data->min_key =
-		btree_type_successor(n1->c.btree_id, n1->key.k.p);
+	btree_set_max(n1, bkey_unpack_pos(n1, prev));
+	btree_set_min(n2, btree_type_successor(n1->c.btree_id, n1->key.k.p));
 
 	set2->u64s = cpu_to_le16((u64 *) vstruct_end(set1) - (u64 *) k);
 	set1->u64s = cpu_to_le16(le16_to_cpu(set1->u64s) - le16_to_cpu(set2->u64s));
@@ -1749,10 +1775,9 @@ void __bch2_foreground_maybe_merge(struct bch_fs *c,
 
 	n = bch2_btree_node_alloc(as, b->c.level);
 
-	n->data->min_key	= prev->data->min_key;
-	n->data->max_key	= next->data->max_key;
+	btree_set_min(n, prev->data->min_key);
+	btree_set_max(n, next->data->max_key);
 	n->data->format		= new_f;
-	n->key.k.p		= next->key.k.p;
 
 	btree_node_set_format(n, new_f);
 
@@ -2202,8 +2227,8 @@ void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
 	bch2_btree_build_aux_trees(b);
 
 	b->data->flags = 0;
-	b->data->min_key = POS_MIN;
-	b->data->max_key = POS_MAX;
+	btree_set_min(b, POS_MIN);
+	btree_set_max(b, POS_MAX);
 	b->data->format = bch2_btree_calc_format(b);
 	btree_node_set_format(b, b->data->format);
 

fs/bcachefs/buckets.c

@@ -1194,6 +1194,7 @@ int bch2_mark_key_locked(struct bch_fs *c,
 		ret = bch2_mark_alloc(c, k, fs_usage, journal_seq, flags);
 		break;
 	case KEY_TYPE_btree_ptr:
+	case KEY_TYPE_btree_ptr_v2:
 		sectors = !(flags & BTREE_TRIGGER_OVERWRITE)
 			?  c->opts.btree_node_size
 			: -c->opts.btree_node_size;
@@ -1729,6 +1730,7 @@ int bch2_trans_mark_key(struct btree_trans *trans, struct bkey_s_c k,
 
 	switch (k.k->type) {
 	case KEY_TYPE_btree_ptr:
+	case KEY_TYPE_btree_ptr_v2:
 		sectors = !(flags & BTREE_TRIGGER_OVERWRITE)
 			?  c->opts.btree_node_size
 			: -c->opts.btree_node_size;

fs/bcachefs/buckets.h

@@ -97,7 +97,8 @@ static inline struct bucket *PTR_BUCKET(struct bch_dev *ca,
 static inline enum bch_data_type ptr_data_type(const struct bkey *k,
 					       const struct bch_extent_ptr *ptr)
 {
-	if (k->type == KEY_TYPE_btree_ptr)
+	if (k->type == KEY_TYPE_btree_ptr ||
+	    k->type == KEY_TYPE_btree_ptr_v2)
 		return BCH_DATA_BTREE;
 
 	return ptr->cached ? BCH_DATA_CACHED : BCH_DATA_USER;

fs/bcachefs/extents.c

@@ -748,6 +748,7 @@ void bch2_bkey_append_ptr(struct bkey_i *k,
 
 	switch (k->k.type) {
 	case KEY_TYPE_btree_ptr:
+	case KEY_TYPE_btree_ptr_v2:
 	case KEY_TYPE_extent:
 		EBUG_ON(bkey_val_u64s(&k->k) >= BKEY_EXTENT_VAL_U64s_MAX);
 
@@ -1030,6 +1031,8 @@ const char *bch2_bkey_ptrs_invalid(const struct bch_fs *c, struct bkey_s_c k)
 
 	if (k.k->type == KEY_TYPE_btree_ptr)
 		size_ondisk = c->opts.btree_node_size;
+	if (k.k->type == KEY_TYPE_btree_ptr_v2)
+		size_ondisk = le16_to_cpu(bkey_s_c_to_btree_ptr_v2(k).v->sectors);
 
 	bkey_extent_entry_for_each(ptrs, entry) {
 		if (__extent_entry_type(entry) >= BCH_EXTENT_ENTRY_MAX)

fs/bcachefs/extents.h

@@ -225,6 +225,13 @@ static inline struct bkey_ptrs_c bch2_bkey_ptrs_c(struct bkey_s_c k)
 			bkey_val_end(r),
 		};
 	}
+	case KEY_TYPE_btree_ptr_v2: {
+		struct bkey_s_c_btree_ptr_v2 e = bkey_s_c_to_btree_ptr_v2(k);
+		return (struct bkey_ptrs_c) {
+			to_entry(&e.v->start[0]),
+			to_entry(extent_entry_last(e))
+		};
+	}
 	default:
 		return (struct bkey_ptrs_c) { NULL, NULL };
 	}
@@ -372,6 +379,13 @@ void bch2_btree_ptr_to_text(struct printbuf *, struct bch_fs *,
 	.swab		= bch2_ptr_swab,			\
 }
 
+#define bch2_bkey_ops_btree_ptr_v2 (struct bkey_ops) {		\
+	.key_invalid	= bch2_btree_ptr_invalid,		\
+	.key_debugcheck	= bch2_btree_ptr_debugcheck,		\
+	.val_to_text	= bch2_btree_ptr_to_text,		\
+	.swab		= bch2_ptr_swab,			\
+}
+
 /* KEY_TYPE_extent: */
 
 const char *bch2_extent_invalid(const struct bch_fs *, struct bkey_s_c);
@@ -416,6 +430,7 @@ static inline bool bkey_extent_is_direct_data(const struct bkey *k)
 {
 	switch (k->type) {
 	case KEY_TYPE_btree_ptr:
+	case KEY_TYPE_btree_ptr_v2:
 	case KEY_TYPE_extent:
 	case KEY_TYPE_reflink_v:
 		return true;

fs/bcachefs/recovery.c

@@ -1010,6 +1010,7 @@ int bch2_fs_recovery(struct bch_fs *c)
 		c->disk_sb.sb->version = le16_to_cpu(bcachefs_metadata_version_current);
 		c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_new_siphash;
 		c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_new_extent_overwrite;
+		c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_btree_ptr_v2;
 		write_sb = true;
 	}
 

fs/bcachefs/replicas.c

@@ -112,6 +112,7 @@ void bch2_bkey_to_replicas(struct bch_replicas_entry *e,
 
 	switch (k.k->type) {
 	case KEY_TYPE_btree_ptr:
+	case KEY_TYPE_btree_ptr_v2:
 		e->data_type = BCH_DATA_BTREE;
 		extent_to_replicas(k, e);
 		break;