staging: erofs: avoid loop in submit chains
As reported by erofs-utils fuzzer, 2 conditions
can happen in corrupted images, which can cause
unexpected behaviors.
- access the same pcluster one more time;
- access the tail end pcluster again, e.g.
_ access again (will trigger tail merging)
|
1 2 3 1 2 -> 1 2 3 1
|_ tail end of the chain \___/ (unexpected behavior)
Let's detect and avoid them now.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190821030908.40282-1-gaoxiang25@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>