From: Kent Overstreet <kent.overstreet@gmail.com>
Date: Tue, 19 Jul 2022 18:51:52 +0000 (-0400)
Subject: bcachefs: Prevent a btree iter overflow in alloc path
X-Git-Tag: v6.7-rc1~201^2~868
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=90cecb921cfe95858a32995019f11c20b6339607;p=thirdparty%2Fkernel%2Flinux.git

bcachefs: Prevent a btree iter overflow in alloc path

In bch2_bucket_alloc_trans(), we're iterating over buckets - but not
directly with an iterator, since we're iterating over the freespace
btree.

This means that we need to clear iter->path->preserve, otherwise we'll
end up retaining a btree_path for every alloc key we touched - which is
not what we want here.

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

diff --git a/fs/bcachefs/alloc_foreground.c b/fs/bcachefs/alloc_foreground.c
index 39e3bb5205ca1..a9f893361c73e 100644
--- a/fs/bcachefs/alloc_foreground.c
+++ b/fs/bcachefs/alloc_foreground.c
@@ -351,6 +351,7 @@ static struct open_bucket *try_alloc_bucket(struct btree_trans *trans, struct bc
 	if (!ob)
 		iter.path->preserve = false;
 err:
+	set_btree_iter_dontneed(&iter);
 	bch2_trans_iter_exit(trans, &iter);
 	printbuf_exit(&buf);
 	return ob;