bcachefs: Data update path won't accidentaly grow replicas

Previously, there was a bug where if an extent had greater durability
than required (because we needed to move a durability=1 pointer and
ended up putting it on a durability 2 device), we would submit a write
for replicas=2 - the durability of the pointer being rewritten - instead
of the number of replicas required to bring it back up to the
data_replicas option.

This, plus the allocation path sometimes allocating on a greater
durability device than requested, meant that extents could continue
having more and more replicas added as they were being rewritten.

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

1 files changed, 5 insertions, 53 deletions

diff --git a/fs/bcachefs/move.c b/fs/bcachefs/move.c
index 71f865352816..3b0a501b6baf 100644
--- a/fs/bcachefs/move.c
+++ b/fs/bcachefs/move.c
@@ -229,49 +229,6 @@ void bch2_move_stats_init(struct bch_move_stats *stats, char *name)
 	scnprintf(stats->name, sizeof(stats->name), "%s", name);
 }
 
-static int bch2_extent_drop_ptrs(struct btree_trans *trans,
-				 struct btree_iter *iter,
-				 struct bkey_s_c k,
-				 struct data_update_opts data_opts)
-{
-	struct bch_fs *c = trans->c;
-	struct bkey_i *n;
-	int ret;
-
-	n = bch2_bkey_make_mut_noupdate(trans, k);
-	ret = PTR_ERR_OR_ZERO(n);
-	if (ret)
-		return ret;
-
-	while (data_opts.kill_ptrs) {
-		unsigned i = 0, drop = __fls(data_opts.kill_ptrs);
-		struct bch_extent_ptr *ptr;
-
-		bch2_bkey_drop_ptrs(bkey_i_to_s(n), ptr, i++ == drop);
-		data_opts.kill_ptrs ^= 1U << drop;
-	}
-
-	/*
-	 * If the new extent no longer has any pointers, bch2_extent_normalize()
-	 * will do the appropriate thing with it (turning it into a
-	 * KEY_TYPE_error key, or just a discard if it was a cached extent)
-	 */
-	bch2_extent_normalize(c, bkey_i_to_s(n));
-
-	/*
-	 * Since we're not inserting through an extent iterator
-	 * (BTREE_ITER_ALL_SNAPSHOTS iterators aren't extent iterators),
-	 * we aren't using the extent overwrite path to delete, we're
-	 * just using the normal key deletion path:
-	 */
-	if (bkey_deleted(&n->k))
-		n->k.size = 0;
-
-	return bch2_trans_relock(trans) ?:
-		bch2_trans_update(trans, iter, n, BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
-		bch2_trans_commit(trans, NULL, NULL, BTREE_INSERT_NOFAIL);
-}
-
 int bch2_move_extent(struct moving_context *ctxt,
 		     struct move_bucket_in_flight *bucket_in_flight,
 		     struct btree_iter *iter,
@@ -341,19 +298,11 @@ int bch2_move_extent(struct moving_context *ctxt,
 	io->rbio.bio.bi_iter.bi_sector	= bkey_start_offset(k.k);
 	io->rbio.bio.bi_end_io		= move_read_endio;
 
-	ret = bch2_data_update_init(trans, ctxt, &io->write, ctxt->wp,
+	ret = bch2_data_update_init(trans, iter, ctxt, &io->write, ctxt->wp,
 				    io_opts, data_opts, iter->btree_id, k);
-	if (ret && ret != -BCH_ERR_unwritten_extent_update)
+	if (ret)
 		goto err_free_pages;
 
-	if (ret == -BCH_ERR_unwritten_extent_update) {
-		bch2_update_unwritten_extent(trans, &io->write);
-		move_free(io);
-		return 0;
-	}
-
-	BUG_ON(ret);
-
 	io->write.op.end_io = move_write_done;
 
 	if (ctxt->rate)
@@ -397,6 +346,9 @@ err_free_pages:
 err_free:
 	kfree(io);
 err:
+	if (ret == -BCH_ERR_data_update_done)
+		return 0;
+
 	this_cpu_inc(c->counters[BCH_COUNTER_move_extent_alloc_mem_fail]);
 	trace_move_extent_alloc_mem_fail2(c, k);
 	return ret;