bcachefs: Issue a transaction restart after commit in repair

bcachefs: Issue a transaction restart after commit in repair

transaction commits invalidate pointers to btree values, and they also
downgrade intent locks.

This breaks the interior btree update path, which takes intent locks and
then calls into the allocator.

This isn't an ideal solution: we can't unconditionally issue a restart
after a transaction commit, because that would break other codepaths.

Reported-by: syzbot+78d82470c16a49702682@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>