bcachefs: Limit pointers to being in only one stripe

This make the disk accounting code saner, and it's not clear why we'd
ever want the same data to be in multiple stripes simultaneously.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/buckets.c

@@ -1027,7 +1027,6 @@ static int bch2_mark_extent(struct bch_fs *c, struct bkey_s_c k,
 	struct extent_ptr_decoded p;
 	struct bch_replicas_padded r;
 	s64 dirty_sectors = 0;
-	unsigned i;
 	int ret;
 
 	r.e.data_type	= data_type;
@@ -1047,17 +1046,15 @@ static int bch2_mark_extent(struct bch_fs *c, struct bkey_s_c k,
 			if (!stale)
 				update_cached_sectors(c, fs_usage, p.ptr.dev,
 						      disk_sectors);
-		} else if (!p.ec_nr) {
+		} else if (!p.has_ec) {
 			dirty_sectors	       += disk_sectors;
 			r.e.devs[r.e.nr_devs++]	= p.ptr.dev;
 		} else {
-			for (i = 0; i < p.ec_nr; i++) {
-				ret = bch2_mark_stripe_ptr(c, p.ec[i],
+			ret = bch2_mark_stripe_ptr(c, p.ec,
 					data_type, fs_usage,
 					disk_sectors, flags);
 			if (ret)
 				return ret;
-			}
 
 			r.e.nr_required = 0;
 		}
@@ -1564,7 +1561,6 @@ static int bch2_trans_mark_extent(struct btree_trans *trans,
 	struct bch_replicas_padded r;
 	s64 dirty_sectors = 0;
 	bool stale;
-	unsigned i;
 	int ret;
 
 	r.e.data_type	= data_type;
@@ -1589,16 +1585,14 @@ static int bch2_trans_mark_extent(struct btree_trans *trans,
 			if (!stale)
 				update_cached_sectors_list(trans, p.ptr.dev,
 							   disk_sectors);
-		} else if (!p.ec_nr) {
+		} else if (!p.has_ec) {
 			dirty_sectors	       += disk_sectors;
 			r.e.devs[r.e.nr_devs++]	= p.ptr.dev;
 		} else {
-			for (i = 0; i < p.ec_nr; i++) {
-				ret = bch2_trans_mark_stripe_ptr(trans, p.ec[i],
+			ret = bch2_trans_mark_stripe_ptr(trans, p.ec,
 					disk_sectors, data_type);
 			if (ret)
 				return ret;
-			}
 
 			r.e.nr_required = 0;
 		}

fs/bcachefs/ec.c

@@ -433,10 +433,9 @@ int bch2_ec_read_extent(struct bch_fs *c, struct bch_read_bio *rbio)
 
 	closure_init_stack(&cl);
 
-	BUG_ON(!rbio->pick.idx ||
-	       rbio->pick.idx - 1 >= rbio->pick.ec_nr);
+	BUG_ON(!rbio->pick.has_ec);
 
-	stripe_idx = rbio->pick.ec[rbio->pick.idx - 1].idx;
+	stripe_idx = rbio->pick.ec.idx;
 
 	buf = kzalloc(sizeof(*buf), GFP_NOIO);
 	if (!buf)

fs/bcachefs/extents.c

@@ -66,7 +66,7 @@ unsigned bch2_bkey_nr_dirty_ptrs(struct bkey_s_c k)
 static unsigned bch2_extent_ptr_durability(struct bch_fs *c,
 					   struct extent_ptr_decoded p)
 {
-	unsigned i, durability = 0;
+	unsigned durability = 0;
 	struct bch_dev *ca;
 
 	if (p.ptr.cached)
@@ -77,16 +77,16 @@ static unsigned bch2_extent_ptr_durability(struct bch_fs *c,
 	if (ca->mi.state != BCH_MEMBER_STATE_FAILED)
 		durability = max_t(unsigned, durability, ca->mi.durability);
 
-	for (i = 0; i < p.ec_nr; i++) {
+	if (p.has_ec) {
 		struct stripe *s =
-			genradix_ptr(&c->stripes[0], p.ec[i].idx);
+			genradix_ptr(&c->stripes[0], p.ec.idx);
 
 		if (WARN_ON(!s))
-			continue;
+			goto out;
 
 		durability = max_t(unsigned, durability, s->nr_redundant);
 	}
-
+out:
 	return durability;
 }
 
@@ -205,10 +205,10 @@ int bch2_bkey_pick_read_device(struct bch_fs *c, struct bkey_s_c k,
 			p.idx++;
 
 		if (force_reconstruct_read(c) &&
-		    !p.idx && p.ec_nr)
+		    !p.idx && p.has_ec)
 			p.idx++;
 
-		if (p.idx >= p.ec_nr + 1)
+		if (p.idx >= (unsigned) p.has_ec + 1)
 			continue;
 
 		if (ret > 0 && !ptr_better(c, p, *pick))
@@ -1543,7 +1543,6 @@ void bch2_extent_ptr_decoded_append(struct bkey_i *k,
 	struct bch_extent_crc_unpacked crc =
 		bch2_extent_crc_unpack(&k->k, NULL);
 	union bch_extent_entry *pos;
-	unsigned i;
 
 	if (!bch2_crc_unpacked_cmp(crc, p->crc)) {
 		pos = ptrs.start;
@@ -1562,9 +1561,9 @@ void bch2_extent_ptr_decoded_append(struct bkey_i *k,
 	p->ptr.type = 1 << BCH_EXTENT_ENTRY_ptr;
 	__extent_entry_insert(k, pos, to_entry(&p->ptr));
 
-	for (i = 0; i < p->ec_nr; i++) {
-		p->ec[i].type = 1 << BCH_EXTENT_ENTRY_stripe_ptr;
-		__extent_entry_insert(k, pos, to_entry(&p->ec[i]));
+	if (p->has_ec) {
+		p->ec.type = 1 << BCH_EXTENT_ENTRY_stripe_ptr;
+		__extent_entry_insert(k, pos, to_entry(&p->ec));
 	}
 }
 

fs/bcachefs/extents.h

@@ -228,7 +228,7 @@ struct bkey_ptrs {
 	__label__ out;							\
 									\
 	(_ptr).idx	= 0;						\
-	(_ptr).ec_nr	= 0;						\
+	(_ptr).has_ec	= false;					\
 									\
 	__bkey_extent_entry_for_each_from(_entry, _end, _entry)		\
 		switch (extent_entry_type(_entry)) {			\
@@ -242,7 +242,8 @@ struct bkey_ptrs {
 					entry_to_crc(_entry));		\
 			break;						\
 		case BCH_EXTENT_ENTRY_stripe_ptr:			\
-			(_ptr).ec[(_ptr).ec_nr++] = _entry->stripe_ptr;	\
+			(_ptr).ec = _entry->stripe_ptr;			\
+			(_ptr).has_ec	= true;				\
 			break;						\
 		}							\
 out:									\

fs/bcachefs/extents_types.h

@@ -21,10 +21,10 @@ struct bch_extent_crc_unpacked {
 
 struct extent_ptr_decoded {
 	unsigned			idx;
-	unsigned			ec_nr;
+	bool				has_ec;
 	struct bch_extent_crc_unpacked	crc;
 	struct bch_extent_ptr		ptr;
-	struct bch_extent_stripe_ptr	ec[4];
+	struct bch_extent_stripe_ptr	ec;
 };
 
 struct bch_io_failures {

fs/bcachefs/replicas.c

@@ -84,10 +84,8 @@ static void extent_to_replicas(struct bkey_s_c k,
 		if (p.ptr.cached)
 			continue;
 
-		if (p.ec_nr) {
+		if (p.has_ec)
 			r->nr_required = 0;
-			break;
-		}
 
 		r->devs[r->nr_devs++] = p.ptr.dev;
 	}