bcachefs: Assorted ec fixes

- The backpointer that ec_stripe_update_ptrs() uses now needs to include
  the snapshot ID, which means we have to change where we add the
  backpointer to after getting the snapshot ID for the new extents

- ec_stripe_update_ptrs() needs to be calling bch2_trans_begin()

- improve error message in bch2_mark_stripe()

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

fs/bcachefs/btree_gc.c

@@ -699,6 +699,7 @@ static int bch2_gc_mark_key(struct bch_fs *c, enum btree_id btree_id,
 		BTREE_TRIGGER_INSERT|
 		BTREE_TRIGGER_GC|
 		(initial ? BTREE_TRIGGER_NOATOMIC : 0);
+	char buf[200];
 	int ret = 0;
 
 	if (initial) {
@@ -717,8 +718,9 @@ static int bch2_gc_mark_key(struct bch_fs *c, enum btree_id btree_id,
 
 		if (test_bit(BCH_FS_REBUILD_REPLICAS, &c->flags) ||
 		    fsck_err_on(!bch2_bkey_replicas_marked(c, *k), c,
-				"superblock not marked as containing replicas (type %u)",
-				k->k->type)) {
+				"superblock not marked as containing replicas\n"
+				"  while marking %s",
+				(bch2_bkey_val_to_text(&PBUF(buf), c, *k), buf))) {
 			ret = bch2_mark_bkey_replicas(c, *k);
 			if (ret) {
 				bch_err(c, "error marking bkey replicas: %i", ret);

fs/bcachefs/buckets.c

@@ -1007,8 +1007,13 @@ static int bch2_mark_stripe(struct bch_fs *c,
 	BUG_ON(gc && old_s);
 
 	if (!m || (old_s && !m->alive)) {
-		bch_err_ratelimited(c, "error marking nonexistent stripe %zu",
-				    idx);
+		char buf1[200], buf2[200];
+
+		bch2_bkey_val_to_text(&PBUF(buf1), c, old);
+		bch2_bkey_val_to_text(&PBUF(buf2), c, new);
+		bch_err_ratelimited(c, "error marking nonexistent stripe %zu while marking\n"
+				    "old %s\n"
+				    "new %s", idx, buf1, buf2);
 		bch2_inconsistent_error(c);
 		return -1;
 	}

fs/bcachefs/ec.c

@@ -837,8 +837,9 @@ static int ec_stripe_update_ptrs(struct bch_fs *c,
 	bch2_trans_iter_init(&trans, &iter, BTREE_ID_extents,
 			     bkey_start_pos(pos),
 			     BTREE_ITER_INTENT);
-
-	while ((k = bch2_btree_iter_peek(&iter)).k &&
+retry:
+	while (bch2_trans_begin(&trans),
+	       (k = bch2_btree_iter_peek(&iter)).k &&
 	       !(ret = bkey_err(k)) &&
 	       bkey_cmp(bkey_start_pos(k.k), pos->p) < 0) {
 		struct bch_extent_ptr *ptr, *ec_ptr = NULL;
@@ -874,11 +875,11 @@ static int ec_stripe_update_ptrs(struct bch_fs *c,
 					BTREE_INSERT_NOFAIL);
 		if (!ret)
 			bch2_btree_iter_set_pos(&iter, next_pos);
-		if (ret == -EINTR)
-			ret = 0;
 		if (ret)
 			break;
 	}
+	if (ret == -EINTR)
+		goto retry;
 	bch2_trans_iter_exit(&trans, &iter);
 
 	bch2_trans_exit(&trans);
@@ -1069,16 +1070,14 @@ void *bch2_writepoint_ec_buf(struct bch_fs *c, struct write_point *wp)
 	return ob->ec->new_stripe.data[ob->ec_idx] + (offset << 9);
 }
 
-void bch2_ec_add_backpointer(struct bch_fs *c, struct write_point *wp,
-			     struct bpos pos, unsigned sectors)
+void bch2_ob_add_backpointer(struct bch_fs *c, struct open_bucket *ob,
+			     struct bkey *k)
 {
-	struct open_bucket *ob = ec_open_bucket(c, &wp->ptrs);
-	struct ec_stripe_new *ec;
+	struct ec_stripe_new *ec = ob->ec;
 
-	if (!ob)
+	if (!ec)
 		return;
 
-	ec = ob->ec;
 	mutex_lock(&ec->lock);
 
 	if (bch2_keylist_realloc(&ec->keys, ec->inline_keys,
@@ -1088,8 +1087,8 @@ void bch2_ec_add_backpointer(struct bch_fs *c, struct write_point *wp,
 	}
 
 	bkey_init(&ec->keys.top->k);
-	ec->keys.top->k.p	= pos;
-	bch2_key_resize(&ec->keys.top->k, sectors);
+	ec->keys.top->k.p	= k->p;
+	ec->keys.top->k.size	= k->size;
 	bch2_keylist_push(&ec->keys);
 
 	mutex_unlock(&ec->lock);

fs/bcachefs/ec.h

@@ -193,8 +193,8 @@ struct ec_stripe_head {
 int bch2_ec_read_extent(struct bch_fs *, struct bch_read_bio *);
 
 void *bch2_writepoint_ec_buf(struct bch_fs *, struct write_point *);
-void bch2_ec_add_backpointer(struct bch_fs *, struct write_point *,
-			     struct bpos, unsigned);
+void bch2_ob_add_backpointer(struct bch_fs *, struct open_bucket *,
+			     struct bkey *);
 
 void bch2_ec_bucket_written(struct bch_fs *, struct open_bucket *);
 void bch2_ec_bucket_cancel(struct bch_fs *, struct open_bucket *);

fs/bcachefs/io.c

@@ -470,6 +470,7 @@ static int bch2_write_index_default(struct bch_write_op *op)
 {
 	struct bch_fs *c = op->c;
 	struct bkey_buf sk;
+	struct open_bucket *ec_ob = ec_open_bucket(c, &op->open_buckets);
 	struct keylist *keys = &op->insert_keys;
 	struct bkey_i *k = bch2_keylist_front(keys);
 	struct btree_trans trans;
@@ -513,6 +514,9 @@ static int bch2_write_index_default(struct bch_write_op *op)
 		if (ret)
 			break;
 
+		if (ec_ob)
+			bch2_ob_add_backpointer(c, ec_ob, &sk.k->k);
+
 		if (bkey_cmp(iter.pos, k->k.p) >= 0)
 			bch2_keylist_pop_front(&op->insert_keys);
 		else
@@ -950,7 +954,6 @@ static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp,
 	struct bio *src = &op->wbio.bio, *dst = src;
 	struct bvec_iter saved_iter;
 	void *ec_buf;
-	struct bpos ec_pos = op->pos;
 	unsigned total_output = 0, total_input = 0;
 	bool bounce = false;
 	bool page_alloc_failed = false;
@@ -1120,9 +1123,6 @@ static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp,
 
 	dst->bi_iter.bi_size = total_output;
 do_write:
-	/* might have done a realloc... */
-	bch2_ec_add_backpointer(c, wp, ec_pos, total_input >> 9);
-
 	*_dst = dst;
 	return more;
 csum_err:

fs/bcachefs/move.c

@@ -8,6 +8,7 @@
 #include "btree_update_interior.h"
 #include "buckets.h"
 #include "disk_groups.h"
+#include "ec.h"
 #include "inode.h"
 #include "io.h"
 #include "journal_reclaim.h"
@@ -135,6 +136,7 @@ int bch2_migrate_index_update(struct bch_write_op *op)
 	struct btree_iter iter;
 	struct migrate_write *m =
 		container_of(op, struct migrate_write, op);
+	struct open_bucket *ec_ob = ec_open_bucket(c, &op->open_buckets);
 	struct keylist *keys = &op->insert_keys;
 	struct bkey_buf _new, _insert;
 	int ret = 0;
@@ -252,6 +254,8 @@ int bch2_migrate_index_update(struct bch_write_op *op)
 		if (!ret) {
 			bch2_btree_iter_set_pos(&iter, next_pos);
 			atomic_long_inc(&c->extent_migrate_done);
+			if (ec_ob)
+				bch2_ob_add_backpointer(c, ec_ob, &insert->k);
 		}
 err:
 		if (ret == -EINTR)